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Sample records for th232 u238 u233

  1. Delayed Fission Gamma-ray Characteristics of Th-232 U-233 U-235 U-238 and Pu-239

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Taylor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    Delayed fission gamma-rays play an important role in determining the time dependent ioniz- ing dose for experiments in the central irradiation cavity of the Annular Core Research Reactor (ACRR). Delayed gamma-rays are produced from both fission product decay and from acti- vation of materials in the core, such as cladding and support structures. Knowing both the delayed gamma-ray emission rate and the time-dependent gamma-ray energy spectrum is nec- essary in order to properly determine the dose contributions from delayed fission gamma-rays. This information is especially important when attempting to deconvolute the time-dependent neutron, prompt gamma-ray, and delayed gamma-ray contribution to the response of a diamond photo-conducting diode (PCD) or fission chamber in time frames of milliseconds to seconds following a reactor pulse. This work focused on investigating delayed gamma-ray character- istics produced from fission products from thermal, fast, and high energy fission of Th-232, U-233, U-235, U-238, and Pu-239. This work uses a modified version of CINDER2008, a transmutation code developed at Los Alamos National Laboratory, to model time and energy dependent photon characteristics due to fission. This modified code adds the capability to track photon-induced transmutations, photo-fission, and the subsequent radiation caused by fission products due to photo-fission. The data is compared against previous work done with SNL- modified CINDER2008 [ 1 ] and experimental data [ 2 , 3 ] and other published literature, includ- ing ENDF/B-VII.1 [ 4 ]. The ability to produce a high-fidelity (7,428 group) energy-dependent photon fluence at various times post-fission can improve the delayed photon characterization for radiation effects tests at research reactors, as well as other applications.

  2. Measurement of neutron-induced fission cross-sections of Th232, U238, U233 and Np237 relative to U235 from 1 MeV to 200 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbakov, O.A.; Laptev, A.B.; Petrov, G.A. [Petersburg Nuclear Physics Inst., Gatchina, Leningrad district (Russian Federation); Fomichev, A.V.; Donets, A.Y.; Osetrov, O.I.

    1998-11-01

    The measurements of neutron-induced cross-section ratios for Th232, U238, U233 and Np237 relative to U235 have been carried out in the energy range from 1 MeV up to 200 MeV using the neutron time-of-flight spectrometer GNEIS based on 1 GeV proton synchrocyclotron. Below 20 MeV, the results of present measurements are roughly in agreement with evaluated data though there are some discrepances to be resolved. (author)

  3. ADSORPTION OF Th-232 AND U-238 BY γ- Al2O3-HUMATE AT SINGLE AND COMPETITIVE SYSTEMS

    Directory of Open Access Journals (Sweden)

    Muzakky Muzakky

    2010-06-01

    Full Text Available The calculation experiments of adsorption capacities of Th-232 and U-238 in γ- Al2O3-humate at single system and competitive with Freundlich method has been done. The purpose of the research is (1 to characterize γ- Al2O3-humat functional groups, (2 to know γ- Al2O3-humat solubility and (3 to predict adsorption capacities of U-238 and of Th-232 at adsorbent γ-Al2O3-humate. The characterization of functional groups γ- Al2O3-humate is done by Fourier Transform Infra red (FTIR Spectrometry. Based on perception results of functional spectra characteristic of γ-Al2O3-humate is similar with humic substance with decrease at stretching -OH at 3400 - 3300 cm-1, and C=O stretching of COOH spectra, C=C aromatic or hydrogen bond of C=O at 1725-1720 cm-1spectra. The solubility testing of γ-Al2O3-humate indicated that the compound it's effective used as adsorption U-238 and of Th-232 at pH 1 to 4 conditions. At single adsorption system with 1000 mg/L of U-238 or Th-232 feed, 0.001 g up to 0.1 g weight of γ-Al2O3-humate were got for U-238 balanced to 992.15 mg/L and 980.66 mg/L for Th-232.  By using regression line curve between ln C and ln x/m, adsorption capacities of U-238 and Th-232 at single system can be calculated as 3.63 mg/g and 2.93 mg/g, respectively, while adsorption capacity of Th-232 was increases to 8.08 mg/g and U-238 decreases to 0.91 mg/g at competitive system.   Keywords: U-238, Th-232, adsorption Freundlich, Spectrometry Fourier Transform Infra Red

  4. Distribution of Natural (U-238, Th-232, Ra-226) and Technogenic (Sr-90, Cs-137) Radionuclides in Soil-Plants Complex Near Issyk-Kul Lake, Kyrgyzstan

    Science.gov (United States)

    Jovanovic, L.; Kaldybaev, B.; Djenbaev, B.; Tilenbaev, A.

    2012-04-01

    Researches on radionuclides distribution in the soil-plants complex provide essential information in understanding human exposure to natural and technogenic sources of radiation. It is necessary in establishing regulation relating to radiation protection. The aim of this study was the radiochemical analysis of the content natural radionuclides 238U, 232Th,226Ra and technogenic radionuclides content (90Sr, 137Cs) in soils near Issyk-Kul lake (Kyrgyzstan). Results of radiochemical analyses have shown, that the concentrations of thorium-232 are fluctuating in the limits (11.7-84.1)-10-4% in the soils. The greatest concentration of thorium-232 has been found in the light chestnut soils. The content of uranium-238 in the soils near Issyk-Kul lake is fluctuating from 2.8 up to 12.7-10-4%. Radium-226 has more migration ability in comparison with other heavy natural radionuclides. According to our research the concentrations of radium-226 are fluctuating in the limits (9.4-43.0)-10-11%. The greatest concentration of radium-226 (43,0±2,8)-10-11% has been determined in the light chestnut soil. In connection with global migration of contaminating substances, including radioactive, the special attention is given long-lived radionuclides strontium-90 and caesium-137 in food-chains, and agroecosystems. Results of radiochemical analyses have shown, that specific activity of strontium-90 is fluctuating in the range of 2.9 up to 11.1 Bq/kg, and caesium-137 from 3.7 up to 14,3 Bq/kg in the soil of agroecosystems in the region of Issyk-Kul. In soil samples down to 1 meter we have observed vertical migration of these radionuclides, they were found to accumulate on the surface of soil horizon (0-5 cm) and their specific activity sharply decreases with depth. In addition in high-mountain pastures characterized by horizontal migration of cattle in profiles of soil, it was discovered that specific activity of radionuclides are lower on the slope than at the foot of the mountain. The content of natural radionuclides (238U, 232Th, 226Ra ) and technogenic radionuclides (90Sr, 137Cs) in the soils depend on many factors: the type and mechanical composition of soil, capacity of absorption, acidity, concentration of exchange forms of carbonates, organic substances. The radionuclides accumulation process in the plants depend on a specific accumulation ability of plants. During the researches it has been found that radionuclides accumulate in vegetative organs more than in reproductive parts of plants. According to the accumulation degrees of natural radionuclides plants taking place in the following decreasing series: sugar beet > potatoes > lucerne > clover > oats > perennial herbs > wheat > annual grass crops > barley > corn. Radiochemical analysis of the technogenic radionuclides in the plants has been determined that specific activity of strontium-90 is increased in leguminous plants (cobs of corn, lucerne) in comparison with other cultures. Caesium-137 is accumulated in beet roots, cobs of corn and lucerne. Key words: natural radionuclides, technogenic radionuclides, soil-plants complex, Issyk-Kul lake, Kyrgyzstan

  5. Total Kinetic Energy and Fragment Mass Distribution of Neutron-Induced Fission of U-233

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, Daniel James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schmitt, Kyle Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tovesson, Fredrik [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-09-29

    Properties of fission in U-233 were studied at the Los Alamos Neutron Science Center (LANSCE) at incident neutron energies from thermal to 40 MeV at both the Lujan Neutron Scattering Center flight path 12 and at WNR flight path 90-Left from Dec 2016 to Jan 2017. Fission fragments are observed in coincidence using a twin ionization chamber with Frisch grids. The average total kinetic energy (TKE) released from fission and fragment mass distributions are calculated from observations of energy deposited in the detector and conservation of mass and momentum. Accurate experimental measurements of these parameters are necessary to better understand the fission process and obtain data necessary for calculating criticality. The average TKE released from fission has been well characterized for several isotopes at thermal neutron energy, however, few measurements have been made at fast neutron energies. This experiment expands on previous successful experiments using an ionization chamber to measure TKE and fragment mass distributions of U-235, U-238, and Pu-239. This experiment requires the full spectrum of neutron energies and can therefore only be performed at a small number of facilities in the world. The required full neutron energy spectrum is obtained by combining measurements from WNR 90L and Lujan FP12 at LANSCE.

  6. Determination of natural radionuclides, U, Th-232, Ra-226, Ra-228, Pb-210 and K-40 in sediments from CananÉIa-Iguape System, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Gleyka J.D.; Chiozzini, Vitor G.; Saueia, Cátia H.R.; Nisti, Marcelo B.; Braga, Elisabete S.; Fávaro, Deborah I.T., E-mail: gjdjesus@ipen.br, E-mail: chsaueia@ipen.br, E-mail: mbnisti@ipen.br, E-mail: defavaro@ipen.br, E-mail: vitor.chio@usp.br, E-mail: edsbraga@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Universidade de São Paulo (USP), SP (Brazil). Instituto Oceanográfico

    2017-07-01

    The Cananéia-Iguape estuarine-lagoon complex, located in the south of São Paulo State, Brazil, is a protected area recognized by UNESCO as part of the Biosphere Reserve, due to its importance as a natural ecosystem. However, along the years, the mining activities in the region affected the river basin, to such an extent that contamination was observed for As, Cu, Pb and Zn. Since the mining activities can also enhance the levels of natural radioactivity in the sediments, this study aimed to determine the activity concentration of the natural radionuclides (K-40, U, Ra-226, Pb-210, Th-232 and Ra-228) in 34 bottom sediments samples collected in the Cananéia-Iguape system. The samples were measured by gamma spectrometry, using a HPGe for the determination of K-40, Ra-226, Pb-210 and Ra-228. The concentration of U and Th-232 was determined by instrumental neutron activation analysis. The activity concentration of K-40 varied from 119 ± 17 to 522 ± 74 Bq kg{sup -1}; U-238 varied from 0.31 ± 0.05 to 5.8 ± 0.3 mg kg{sup -1}; Ra-226 varied from 3.7 ± 0.3 to 43.3 ± 1.5 Bq kg{sup -1}; Pb-210 varied from 5.8 ± 2.6 to 118 ± 12 Bq kg{sup -1}; Th-232 varied from 0.67 ± 0.02 to 16.6 ± 0.4 mg kg{sup -1} and Ra-228 varied from 3.5 ± 0.6 to 64.9 ± 2.4 Bq kg{sup -1}. These results were compared with literature values for the region, indicating that they are the background of the region and no contamination was observed from NORM (Naturally Occurring Radioactive Material) industries. (author)

  7. Th/U-233 multi-recycle in PWRs.

    Energy Technology Data Exchange (ETDEWEB)

    Yun, D.; Kim, T. K.; Taiwo, T. A.; Nuclear Engineering Division

    2010-09-07

    The use of thorium in current or advanced light water reactors (LWRs) has been of interest in recent years. These interests have been associated with the need to increase nuclear fuel resources and the perceived non-proliferation advantages of the utilization of thorium in the fuel cycle. Various options have been considered for the use of thorium in the LWR fuel cycle including: (1) its use in a once-through fuel cycle to replace non-fissile uranium or to extend fuel burnup due to its attractive fertile material conversion, (2) its use for fissile plutonium burning in limited recycle cores, and (3) its advantage in limiting the transuranic elements to be disposed off in a repository (if only Th/U-233 fuel is used). The possibility for thorium utilization in multirecycle system has also been considered by various researchers, primarily because of the potential for near breeders with Th/U-233 in the thermal energy range. The objective of this project is to evaluate the potential of the Th/U-233 fuel multirecycle in current LWRs, with focus this year on pressurized water reactors (PWRs). In this work, approaches for ensuring a sustainable multirecycle without the need for external source of makeup fissile material have been investigated. The intent is to achieve a design that allows existing PWRs to be used with minimal modifications. In all cases including homogeneous and heterogeneous assembly designs, the assembly pitch is kept consistent with that of the current PWRs (21.5 cm used). Because of design difficulties associated with using the same geometry and dimensions as a PWR core, the potential modifications (other than assembly pitch) that would be needed for PWRs to ensure a sustainable multirecycle system have been investigated and characterized. Additionally, the implications of the use of thorium on the LWR fuel cycle are discussed. In Section 2, background information on studies evaluating the use of thorium in the fuel cycle is provided, but focusing on

  8. 450,000 years of groundwater (234U/238U)0 variations in SW Nevada, USA

    Science.gov (United States)

    Wendt, Kathleen A.; Moseley, Gina E.; Pythoud, Mathieu; Dublyansky, Yuri; Edwards, R. Lawrence; Spötl, Christoph

    2017-04-01

    Subaqueous speleothems represent a unique archive for geochemical variations in regional groundwater systems. Devils Hole 2 cave, located in SW Nevada, USA, is an open fault zone intersecting the Ash Meadows groundwater flow system. Speleothem layers that coat the submerged walls of Devils Hole 2 cave record the isotopic composition of groundwater uranium at the time of precipitation. Past variations of 234U/238U initial activity ratios in groundwater may provide insight into paleohydrological conditions, such as changes to groundwater flow rates or source inputs. We aim to reconstruct 450 ka of groundwater (234U/238U)0 variations at Devils Hole 2 cave. To do so, an 80 cm-long core was drilled from the cave wall. Over 100 (234U/238U) and U-Th ages were measured in order to calculate initial activity ratios. Despite relatively constant uranium concentrations and growth rates throughout the core, preliminary results show a range in values (2.851 -2.616) deviating from modern day groundwater (234U/238U)0 which we measured to 2.762 (±0.002). (234U/238U)0 variations appear to follow interglacial-glacial cycles from 450 ka to present day, such that maximum (234U/238U)0 ratios identified at roughly 43, 185, 289, 374, and 449 ka correspond to glacial periods, while minimum (234U/238U)0 ratios at roughly 5, 121, 239, 336 and 422 ka correspond to interglacial periods. Focusing on the last 200 ka, we observe increasing (234U/238U)0 ratios coupled with depleted Devils Hole 2 δ18O values and water table high-stands (Moseley et al. 2016, Science 2016). We suggest that (234U/238U)0 variations are positively correlated to precipitation amount, contrary to dripstone speleothem records in the Great Basin region. Mechanisms driving the fluctuation in (234U/238U)0 values are still uncertain, but may be due to increased inputs of additional minor groundwater sources to the Ash Meadows flow system during pluvial periods.

  9. New explanation for extreme u-234 u-238 disequilibria in a dolomitic aquifer

    CSIR Research Space (South Africa)

    Kronfeld, J

    1994-05-01

    Full Text Available High U-234/U-238 activity ratios are found in the shallow groundwater of the phreatic Transvaal Dolomite Aquifer. The aquifer is uranium poor, while the waters are oxygen rich and young. Tritium and C-14 are used to show that the disequilibrium...

  10. 234U/238U as a ground-water tracer, SW Nevada-SE California

    Science.gov (United States)

    Ludwig, K. R.; Peterman, Z.E.; Simmons, K.R.; Gutentag, E.D.

    1993-01-01

    The 234U/238U ratio of uranium in oxidizing ground waters is potentially an excellent ground-water tracer because of its high solubility and insensitivity to chemical reactions. Moreover, recent advances in analytical capability have made possible very precise uranium-isotopic analyses on modest (approx.100 ml) amounts of normal ground water. Preliminary results on waters from SW Nevada/Se California indicate two main mixing trends, but in detail indicate significant complexity requiring three or more main components.

  11. Research on the reliability of measurement of natural radioactive nuclide concentration of U-238

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Seok Ki; Kim, Gee Hyun [Dept. of Nuclear engineering, Univ. of SeJong, Seoul (Korea, Republic of); Joo, Sun Dong; Lee, Hoon [KoFONS, Seongnam (Korea, Republic of)

    2016-12-15

    Naturally occurred radioactive materials (NORM) can be found all around us and people are exposed to this no matter what they do or where they live. In this study, two indirect measurement methods of NORM U-238 has been reviewed; one that has used HPGe on the basis of the maintenance, and the other is disequilibrium theory of radioactive equilibrium relationships of mother and daughter nuclide at Decay-chain of NORM U-238. For this review, complicated pre-processing process (Breaking->Fusion->Chromatography->Electron deposit) has been used , and then carried out a comparative research with direct measurement method that makes use of and measures Alpha spectrometer. Through the experiment as above, we could infer the daughter nuclide whose radioactive equilibrium has been maintained with U-238. Therefore, we could find out that the daughter nuclide suitable to be applied to Gamma indirect measurement method was Th-234. Due to Pearson Correlation statistics, we could find out the reliability of the result value that has been analyzed by using Th-234.

  12. Water Ingress Testing of the Turbula Jar and U-233 Lead Pig Containers

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Kirk Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karns, Tristan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Paul Herrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-02

    Understanding the water ingress behavior of containers used at the TA-55 Plutonium Facility has significant implications for criticality safety. The purpose of this report is to document the water ingress behavior of the Turbula Jar with Bakelite lid and Viton gaskets (Turbula Jar) used in oxide blending operations and the U-233 lead pig container used to store and transport U-233 material. The technical basis for water resistant containers at TA-55 is described in LA-UR-15-22781, “Water Resistant Container Technical Basis Document for the TA-55 Criticality Safety Program.” Testing of the water ingress behavior of various containers is described in LA-CP-13-00695, “Water Penetration Tests on the Filters of Hagan and SAVY Containers,” LA-UR-15-23121, “Water Ingress into Crimped Convenience Containers under Flooding Conditions,” and in LA-UR- 16-2411, “Water Ingress Testing for TA-55 Containers.” Water ingress criteria are defined in TA55-AP-522 “TA-55 Criticality Safety Program”, and in PA-RD-01009 “TA55 Criticality Safety Requirements.” The water ingress criteria for submersion is no more than 50 ml of water ingress at a 6” water column height for a period of 2 hours.

  13. Temporal Variations in 234U/238U Activity Ratios in Four Mississippi River Tributaries

    Science.gov (United States)

    Grzymko, T. J.; Marcantonio, F.

    2005-05-01

    In 2004 we sampled the four tributaries that are the major contributors to the Mississippi River in terms of water discharge, i.e., the Arkansas, Missouri, Upper Mississippi, and Ohio rivers. Each river was sampled four times over the course of the year at variable levels of discharge in an attempt to constrain the causes of the temporal variations of 234U/238U activity ratios in the lower Mississippi River at New Orleans. The tributary uranium data support the idea that lower river uranium isotope and elemental systematics are controlled by a simple mass balance of the source tributary discharges. Furthermore, the uranium isotope ratios of the individual tributaries show coherent patterns of variability. Specifically, the data obtained from the four sampling trips yielded similar patterns of temporal variation in the 234U/238U activity ratios of all of the rivers, although the absolute values of these ratios were distinctly different from one river to the next. The pattern was such that the highest 234U/238U activity ratios were observed during the highest flow associated with the spring freshet while the lowest ratios occurred during the summer. For example, in the Missouri River, the 234U/238U activity ratios varied from 1.51 (February 12) to 1.37 (April 14) to 1.34 (July 16) to 1.37 (November 12), while in the Ohio River the same ratios varied from 1.36 (February 12) to 1.29 (April 14) to 1.21 (July 16) to 1.23 (November 12). The apparent seasonal pattern of these ratios in each tributary has led to several ideas as to the causes of the observed trends. The first, and most obvious, is that in each individual drainage basin there are various source tributaries that contribute to the uranium isotope systematics of the main stem of the tributary of interest. It follows that the variations in the uranium activity ratios may be caused by spatial variations in the source rock chemistry of the drainage basin. Other more complex scenarios can also be envisioned and

  14. Depth profile of 236U/238U in soil samples in La Palma, Canary Islands

    Science.gov (United States)

    Srncik, M.; Steier, P.; Wallner, G.

    2011-01-01

    The vertical distribution of the 236U/238U isotopic ratio was investigated in soil samples from three different locations on La Palma (one of the seven Canary Islands, Spain). Additionally the 240Pu/239Pu atomic ratio, as it is a well establish tool for the source identification, was determined. The radiochemical procedure consisted of a U separation step by extraction chromatography using UTEVA® Resin (Eichrom Technologies, Inc.). Afterwards Pu was separated from Th and Np by anion exchange using Dowex 1x2 (Dow Chemical Co.). Furthermore a new chemical procedure with tandem columns to separate Pu and U from the matrix was tested. For the determination of the uranium and plutonium isotopes by alpha spectrometry thin sources were prepared by microprecipitation techniques. Additionally these fractions separated from the soil samples were measured by Accelerator Mass Spectrometry (AMS) to get information on the isotopic ratios 236U/238U, 240Pu/239Pu and 236U/239Pu, respectively. The 236U concentrations [atoms/g] in each surface layer (∼2 cm) were surprisingly high compared to deeper layers where values around two orders of magnitude smaller were found. Since the isotopic ratio 240Pu/239Pu indicated a global fallout signature we assume the same origin as the probable source for 236U. Our measured 236U/239Pu value of around 0.2 is within the expected range for this contamination source. PMID:21481502

  15. Crustal subsidence rate off Hawaii determined from 234U/238U ages of drowned coral reefs

    Science.gov (United States)

    Ludwig, K. R.; Szabo, B. J.; Moore, J.G.; Simmons, K.R.

    1991-01-01

    A series of submerged coral reefs off northwestern Hawaii was formed during (largely glacial) intervals when the rate of local sea-level rise was less than the maximum upward growth rate of the reefs. Mass-spectrometric 234U/238U ages for samples from six such reefs range from 17 to 475 ka and indicate that this part of the Hawaiian Ridge has been subsiding at a roughly uniform rate of 2.6 mm/yr for the past 475 ka. The 234U/238U ages are in general agreement with model ages of reef drowning (based on estimates of paleo-sea-level stands derived from oxygen-isotope ratios of deep-sea sediments), but there are disagreements in detail. The high attainable precision (??10 ka or better on samples younger than ~800 ka), large applicable age range, relative robustness against open-system behavior, and ease of analysis for this technique hold great promise for future applications of dating of 50-1000 ka coral. -Authors

  16. Development of fast measurements of concentration of NORM U-238 by HPGe

    Science.gov (United States)

    Cha, Seokki; Kim, Siu; Kim, Geehyun

    2017-02-01

    Naturally Occureed Radioactive Material (NORM) generated from the origin of earth can be found all around us and even people who are not engaged in the work related to radiation have been exposed to unnecessary radiation. This NORM has a potential risk provided that is concentrated or transformed by artificial activities. Likewise, a development of fast measruement method of NORM is emerging to prevent the radiation exposure of the general public and person engaged in the work related to the type of business related thereto who uses the material in which NORM is concentrated or transfromed. Based on such a background, many of countries have tried to manage NORM and carried out regulatory legislation. To effienctly manage NORM, there is need for developing new measurement to quickly and accurately analyze the nuclide and concentration. In this study, development of the fast and reliable measurement was carried out. In addition to confirming the reliability of the fast measurement, we have obtained results that can suggest the possibility of developing another fast measurement. Therefore, as a follow-up, it is possible to develop another fast analytical measurement afterwards. The results of this study will be very useful for the regulatory system to manage NORM. In this study, a review of two indirect measurement methods of NORM U-238 that has used HPGe on the basis of the equilibrium theory of relationships of mother and daughter nuclide at decay-chain of NORM U-238 has been carried out. For comparative study(in order to know reliabily), direct measurement that makes use of alpha spectrometer with complicated pre-processing process was implemented.

  17. Assessment of uranium exposure from total activity and 234U:238U activity ratios in urine.

    Science.gov (United States)

    Nicholas, T; Bingham, D

    2011-03-01

    Radiation workers at Atomic Weapons Establishment (AWE) are monitored for uranium exposure by routine bioassay sampling (primarily urine sampling). However, the interpretation of uranium in urine and faecal results in terms of occupational intakes is difficult because of the presence of uranium due to intakes from environmental (dietary) sources. For uranium in urine data obtained using current analytical techniques at AWE, the mean, median and standard deviation of excreted uranium concentrations were 0.006, 0.002 and 0.012 μg per g creatinine, respectively. These values are consistent with what might be expected from local dietary intakes and the knowledge that occupational exposures at AWE are likely to be very low. However, some samples do exceed derived investigation levels (DILs), which have been set up taking account of the likely contribution from environmental sources. We investigate how the activity and isotopic composition of uranium in the diet affects the sensitivity of uranium in urine monitoring for occupational exposures. We conclude that DILs based on both total uranium in urine activity and also (234)U:(238)U ratios are useful given the likely variation in dietary contribution for AWE workers. Assuming a background excretion rate and that the enrichment of the likely exposure is known, it is possible to assess exposures using (234)U:(238)U ratios and/or total uranium activity. The health implications of internalised uranium, enriched to 235)U, centre on its nephrotoxicity; the DILs for bioassay samples at AWE are an order of magnitude below the conservative recommendations made by the literature.

  18. Neutron Productions from thin Be target irradiated by 50 MeV/u 238U beam

    Directory of Open Access Journals (Sweden)

    Lee Hee-Seock

    2017-01-01

    Full Text Available Neutrons generated from thin beryllium target by 50 MeV/u 238U beam were measured using activation analysis at 15, 30, 45, and 90 degrees from the beam direction. A 0.085 mm-thick Be stripper of RIBF was used as the neutron generating target. Activation detectors of bismuth, cobalt, and aluminum were placed out of the stripper chamber. The threshold reactions of 209Bi(n, xn210-xBi(x=4~8, 59Co(n, xn60-xCO(x=2~5, 59Co(n, 2nα54Mn, 27Al(n, α24Na, and 27Al(n,2nα22Na were applied to measure the production rates of radionuclides. The neutron spectra were obtained using an unfolding method with the SAND-II code. All of production rates and neutron spectra were compared with the calculated results using Monte Carlo codes, the PHITS and the FLUKA. The FLUKA results showed better agreement with the measurements than the PHITS. The discrepancy between the measurements and the calculations were discussed.

  19. Depth profiling of residual activity of U237 fragments as a range verification technique for U238 primary ion beam

    Science.gov (United States)

    Strašík, I.; Chetvertkova, V.; Mustafin, E.; Pavlovič, M.; Belousov, A.

    2012-07-01

    Experimental and simulation data concerning fragmentation of U238 ion beam in aluminum, copper, and stainless-steel targets with the initial energy 500 and 950MeV/u are collected in the paper. A range-verification technique based on depth profiling of residual activity is presented. The irradiated targets were constructed in the stacked-foil geometry and analyzed using gamma-ray spectroscopy. One of the purposes of these experiments was depth profiling of residual activity of induced nuclides and projectile fragments. Among the projectile fragments, special attention is paid to the U237 isotope that has a range very close to the range of the primary U238 ions. Therefore, the depth profiling of the U237 isotope can be utilized for experimental verification of the U238 primary-beam range, which is demonstrated and discussed in the paper. The experimental data are compared with computer simulations by FLUKA, SRIM, and ATIMA, as well as with complementary experiments.

  20. 234U/238U evidence for local recharge and patterns of groundwater flow in the vicinity of Yucca Mountain, Nevada, USA

    Science.gov (United States)

    Paces, J.B.; Ludwig, K. R.; Peterman, Z.E.; Neymark, L.A.

    2002-01-01

    Uranium concentrations and 234U/238U ratios in saturated-zone and perched ground water were used to investigate hydrologic flow and downgradient dilution and dispersion in the vicinity of Yucca Mountain, a potential high-level radioactive waste disposal site. The U data were obtained by thermal ionization mass spectrometry on more than 280 samples from the Death Valley regional flow system. Large variations in both U concentrations (commonly 0.6-10 ??g 1-1) and 234U/238U activity ratios (commonly 1.5-6) are present on both local and regional scales; however, ground water with 234U/238U activity ratios from 7 up to 8.06 is restricted largely to samples from Yucca Mountain. Data from ground water in the Tertiary volcanic and Quaternary alluvial aquifers at and adjacent to Yucca Mountain plot in 3 distinct fields of reciprocal U concentration versus 234U/238U activity ratio correlated to different geographic areas. Ground water to the west of Yucca Mountain has large U concentrations and moderate 234U/238U whereas ground water to the east in the Fortymile flow system has similar 234U/238U, but distinctly smaller U concentrations. Ground water beneath the central part of Yucca Mountain has intermediate U concentrations but distinctive 234U/238U activity ratios of about 7-8. Perched water from the lower part of the unsaturated zone at Yucca Mountain has similarly large values of 234U/238U. These U data imply that the Tertiary volcanic aquifer beneath the central part of Yucca Mountain is isolated from north-south regional flow. The similarity of 234U/238U in both saturated- and unsaturated-zone ground water at Yucca Mountain further indicates that saturated-zone ground water beneath Yucca Mountain is dominated by local recharge rather than regional flow. The distinctive 234U/238U signatures also provide a natural tracer of downgradient flow. Elevated 234U/238U in ground water from two water-supply wells east of Yucca Mountain are interpreted as the result of induced

  1. Uranium contents and (235)U/(238)U atom ratios in soil and earthworms in western Kosovo after the 1999 war.

    Science.gov (United States)

    Di Lella, L A; Nannoni, F; Protano, G; Riccobono, F

    2005-01-20

    The uranium content and (235)U/(238)U atom ratio were determined in soils and earthworms of an area of Kosovo (Djakovica garrison), heavily shelled with depleted uranium (DU) ammunition during the 1999 war. The aim of the study was to reconstruct the small-scale distribution of uranium and assess the influence of the DU added to the surface environment. The total uranium concentration and the (235)U/(238)U ratio of topsoils showed great variability and were inversely correlated. The highest uranium levels (up to 31.47 mg kg(-1)) and lowest (235)U/(238)U ratios (minimum 0.002147) were measured in topsoils collected inside, or very close to, the clusters of DU penetrator holes. Regarding the fractionation of uranium in the surface soils, the uranium concentrations in the soluble and exchangeable fractions increased as the total uranium concentration of the topsoils increased. High and rather uniform percentage contents of uranium (24-36%) were associated with the poorly crystalline iron oxide phases of soils. In the U-enriched soils the elevated levels of the element were probably due to the presence of very small, unevenly distributed oxidized DU particles. The total uranium concentration in earthworms was in the range 0.142-0.656 mg kg(-1), with the highest concentrations in Lumbricus terrestris. The juveniles of all three studied species seemed to accumulate uranium more than adults, probably due to age-related differences in metabolism. The (235)U/(238)U ratio in the earthworms was variable (0.005241-0.007266) and independent of both the total uranium contents in soils and the absolute uranium levels in the animals. Bioconcentration was greater at lower U concentrations in soil, probably due to an increasing rate of elimination of uranium by the earthworms as the soil contents of the element increase. The results of this study clearly indicate that DU was added to the soil of the study area. Nevertheless, the phenomenon was very limited spatially and the total

  2. Effect of U-238 and U-235 cross sections on nuclear characteristics of fast and thermal reactors

    Energy Technology Data Exchange (ETDEWEB)

    Akie, Hiroshi; Takano, Hideki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kaneko, Kunio

    1997-03-01

    Benchmark calculation has been made for fast and thermal reactors by using ENDF/B-VI release 2(ENDF/B-VI.2) and JENDL-3.2 nuclear data. Effective multiplication factors (k{sub eff}s) calculated for fast reactors calculated with ENDF/B-VI.2 becomes about 1% larger than the results with JENDL-3.2. The difference in k{sub eff} is caused mainly from the difference in inelastic scattering cross section of U-238. In all thermal benchmark cores, ENDF/B-VI.2 gives smaller multiplication factors than JENDL-3.2. In U-235 cores, the difference is about 0.3%dk and it becomes about 0.6% in TCA U cores. The difference in U-238 data is also important in thermal reactors, while there are found 0.1-0.3% different v values of U isotopes in thermal energy between ENDF/B-VI.2 and JENDL-3.2. (author)

  3. INDEPENDENT AND CUMULATIVE YIELDS OF VERY NEUTRON-RICH NUCLEI IN 20 MEV P-INDUCED AND 18-41 MEV D-INDUCED FISSION OF U-238

    NARCIS (Netherlands)

    LEINO, M; JAUHO, PP; AYSTO, J; DECROCK, P; DENDOOVEN, P; ESKOLA, K; HUYSE, M; JOKINEN, A; PARMONEN, JM; PENTTILA, H; REUSEN, G; TASKINEN, P; VANDUPPEN, P; WAUTERS, J

    Independent and cumulative yields in nearly symmetric fission have been measured for the first time by bombarding U-238 with 20-MeV protons and with 18-, 25-, and 41-MeV deuterons. Isobaric charge dispersion has been determined in the A = 110, A = 112, and A = 114 mass chains and, from asymmetric

  4. Determination of extremely low (236)U/(238)U isotope ratios in environmental samples by sector-field inductively coupled plasma mass spectrometry using high-efficiency sample introduction.

    Science.gov (United States)

    Boulyga, Sergei F; Heumann, Klaus G

    2006-01-01

    A method by inductively coupled plasma mass spectrometry (ICP-MS) was developed which allows the measurement of (236)U at concentration ranges down to 3 x 10(-14)g g(-1) and extremely low (236)U/(238)U isotope ratios in soil samples of 10(-7). By using the high-efficiency solution introduction system APEX in connection with a sector-field ICP-MS a sensitivity of more than 5,000 counts fg(-1) uranium was achieved. The use of an aerosol desolvating unit reduced the formation rate of uranium hydride ions UH(+)/U(+) down to a level of 10(-6). An abundance sensitivity of 3 x 10(-7) was observed for (236)U/(238)U isotope ratio measurements at mass resolution 4000. The detection limit for (236)U and the lowest detectable (236)U/(238)U isotope ratio were improved by more than two orders of magnitude compared with corresponding values by alpha spectrometry. Determination of uranium in soil samples collected in the vicinity of Chernobyl nuclear power plant (NPP) resulted in that the (236)U/(238)U isotope ratio is a much more sensitive and accurate marker for environmental contamination by spent uranium in comparison to the (235)U/(238)U isotope ratio. The ICP-MS technique allowed for the first time detection of irradiated uranium in soil samples even at distances more than 200 km to the north of Chernobyl NPP (Mogilev region). The concentration of (236)U in the upper 0-10 cm soil layers varied from 2 x 10(-9)g g(-1) within radioactive spots close to the Chernobyl NPP to 3 x 10(-13)g g(-1) on a sampling site located by >200 km from Chernobyl.

  5. Nuclear orientation in the reaction S34+U238 and synthesis of the new isotope Hs268

    Science.gov (United States)

    Nishio, K.; Hofmann, S.; Heßberger, F. P.; Ackermann, D.; Antalic, S.; Aritomo, Y.; Comas, V. F.; Düllmann, Ch. E.; Gorshkov, A.; Graeger, R.; Hagino, K.; Heinz, S.; Heredia, J. A.; Hirose, K.; Ikezoe, H.; Khuyagbaatar, J.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R.; Mitsuoka, S.; Nagame, Y.; Nishinaka, I.; Ohtsuki, T.; Popeko, A. G.; Saro, S.; Schädel, M.; Türler, A.; Watanabe, Y.; Yakushev, A.; Yeremin, A. V.

    2010-08-01

    The synthesis of isotopes of the element hassium was studied using the reaction S34+U238→Hs272*. At a kinetic energy of 163.0 MeV in the center-of-mass system we observed one α-decay chain starting at the isotope Hs267. The cross section was 1.8-1.5+4.2 pb. At 152.0 MeV one decay of the new isotope Hs268 was observed. It decays with a half-life of 0.38-0.17+1.8 s by 9479±16 keV α-particle emission. Spontaneous fission of the daughter nucleus Sg264 was confirmed. The measured cross section was 0.54-0.45+1.3 pb. In-beam measurements of fission-fragment mass distributions were performed to obtain information on the fusion probability at various orientations of the deformed target nucleus. The distributions changed from symmetry to asymmetry when the beam energy was changed from above-barrier to sub-barrier values, indicating orientation effects on fusion and/or quasifission. It was found that the distribution of symmetric mass fragments originates not only from fusion-fission, but has a strong component from quasifission. The result was supported by a calculation based on a dynamical description using the Langevin equation, in which the mass distributions for fusion-fission and quasifission fragments were separately determined.

  6. On monitoring anthropogenic airborne uranium concentrations and (235)U/(238)U isotopic ratio by Lichen - bio-indicator technique.

    Science.gov (United States)

    Golubev, A V; Golubeva, V N; Krylov, N G; Kuznetsova, V F; Mavrin, S V; Aleinikov, A Yu; Hoppes, W G; Surano, K A

    2005-01-01

    Lichens are widely used to assess the atmospheric pollution by heavy metals and radionuclides. However, few studies are available in publications on using lichens to qualitatively assess the atmospheric pollution levels. The paper presents research results applying epiphytic lichens as bio-monitors of quantitative atmospheric contamination with uranium. The observations were conducted during 2.5 years in the natural environment. Two experimental sites were used: one in the vicinity of a uranium contamination source, the other one - at a sufficient distance away to represent the background conditions. Air and lichens were sampled at both sites monthly. Epiphytic lichens Hypogimnia physodes were used as bio-indicators. Lichen samples were taken from various trees at about 1.5m from the ground. Air was sampled with filters at sampling stations. The uranium content in lichen and air samples as well as isotopic mass ratios (235)U/(238)U were measured by mass-spectrometer technique after uranium pre-extraction. Measured content of uranium were 1.45 mgkg(-1) in lichen at 2.09 E-04 microgm(-3) in air and 0.106 mgkg(-1) in lichen at 1.13 E-05 microgm(-3) in air. The relationship of the uranium content in atmosphere and that in lichens was determined, C(AIR)=exp(1.1 x C(LICHEN)-12). The possibility of separate identification of natural and man-made uranium in lichens was demonstrated in principle.

  7. Storage and disposition of weapons usable fissile materials (FMD) PEIS: Blending of U-233 to {lt}12% or {lt}5% enrichment at the Idaho National Engineering Laboratory. Data report, Draft: Version 1

    Energy Technology Data Exchange (ETDEWEB)

    Shaber, E.L.

    1995-08-01

    Uranium-233 (U-233), a uranium isotope, is a fissionable material capable of fueling nuclear reactors or being utilized in the manufacturing of nuclear weapons. As such, it is controlled as a special nuclear material. The Idaho National Engineering Laboratory (INEL) and Oak Ridge National Laboratory (ORNL) currently store the Department of Energy`s (DOE`s) supply of unirradiated U-233 fuel materials. Irradiated U-233 is covered by the national spent nuclear fuel (SNF) program and is not in the scope of this report. The U-233 stored at ORNL is relatively pure uranium oxide in the form of powder or monolithic solids. This material is currently stored in stainless steel canisters of variable lengths measuring about 3 inches in diameter. The ORNL material enrichment varies with some material containing considerable amounts of U-235. The INEL material is fuel from the Light Water Breeder Reactor (LWBR) Program and consists of enriched uranium and thorium oxides in zircaloy cladding. The DOE inventory of U-233 contains trace quantities of U-232, and daughter products from the decay of U-232 and U-233, resulting in increased radioactivity over time. These increased levels of radioactivity generally result in the need for special handling considerations.

  8. 234U/238U Disequilibria along sedimentary discontinuities in a deep formation: late diagenetic U-relocation processes vs. large scale fluid circulation evidence ?

    Science.gov (United States)

    Deschamps, P.; Hillaire-Marcel, C.; Michelot, J.-L.; Doucelance, R.; Ghaleb, B.

    2003-04-01

    This work is part of geological investigations undertaken by the French Agency for Nuclear Waste Management (ANDRA) in order to study the safety of radioactive waste repository in deep geological clay layers. The target formation, from Mesozoic sedimentary rocks of the eastern Paris basin (France), is a thick (130--145 m), 400--500 m deep, Callovo-Oxfordian argilite unit, that is over- and underlain by Oxfordian and Bathonian limestones, respectively. Borehole core samples have been analysed for their uranium content and 234U/238U isotopic composition in order to examine the state of radioactive equilibrium existing between these two radionuclides naturally occurring in the rock. Any observations of disequilibrium should allow i) to document the mobility of these actinides in such deposits, and ii) to constrain the time scale of the geological phenomena responsible for it. Highly precise and accurate (234U/238U) analyses were obtained using Multiple Collector Inductively Coupled Plasma Mass Spectrometry. The overall reproducibility, including both chemical separation and spectrometric measurement, is about 0.15% (2σ). Most samples of the target formation and its bounding rocks display secular equilibrium. However, in the Bathonian formation near the interface with the argilite layer, significant (234U/238U) disequilibria are observed along sub-horizontal sedimentary discontinuities, identified as styloliths, indicating that the process involved has been active during the last Ma. Isotopic and elemental compositions of uranium have been determined along a transect, perpendicular to a major discontinuity. The transect exhibits a symmetric pattern relative to this discontinuity with: (1) an increase of the U-concentration towards the stylolitic joint and (2) a sharp transition between significant (234U/238U) < 1 disequilibria in the stylolith to an excess of 234U ((234U/238U) = 1.05) in the vicinity of the joint, followed by a smooth decrease of the activity ratio

  9. CREATING THE KULTUK POLYGON FOR EARTHQUAKE PREDICTION: VARIATIONS OF (234U/238U) AND 87SR/86SR IN GROUNDWATER FROM ACTIVE FAULTS AT THE WESTERN SHORE OF LAKE BAIKAL

    OpenAIRE

    S. V. Rasskazov; E. P. Chebykin; A. M. Ilyasova; E. N. Vodneva; I. S. Chuvashova; S. A. Bornyakov; A. K. Seminsky; S. V. Snopkov; V. V. Chechel'nitsky; N. A. Gileva

    2015-01-01

    Introduction. Determinations of (234U/238U) in groundwater samples are used for monitoring current deformations in active faults (parentheses denote activity ratio units). The cyclic equilibrium of activity ratio 234U/238U≈≈(234U/238U)≈γ≈1 corresponds to the atomic ratio ≈5.47×10–5. This parameter may vary due to higher contents of 234U nuclide in groundwater as a result of rock deformation. This effect discovered by P.I. Chalov and V.V. Cherdyntsev was described in [Cherdyntsev, 1969, 1973; ...

  10. Trace element distribution and 235U/238U ratios in Euphrates waters and in soils and tree barks of Dhi Qar province (southern Iraq).

    Science.gov (United States)

    Riccobono, Francesco; Perra, Guido; Pisani, Anastasia; Protano, Giuseppe

    2011-09-01

    To assess the quality of the environment in southern Iraq after the Gulf War II, a geochemical survey was carried out. The survey provided data on the chemistry of Euphrates waters, as well as the trace element contents, U and Pb isotopic composition, and PAH levels in soil and tree bark samples. The trace element concentrations and the (235)U/(238)U ratio values in the Euphrates waters were within the usual natural range, except for the high contents of Sr due to a widespread presence of gypsum in soils of this area. The trace element contents in soils agreed with the common geochemistry of soils from floodplain sediments. Some exceptions were the high contents of Co, Cr and Ni, which had a natural origin related to ophiolitic outcrops in the upper sector of the Euphrates basin. The high concentrations of S and Sr were linked to the abundance of gypsum in soils. A marked geochemical homogeneity of soil samples was suggested by the similar distribution pattern of rare earth elements, while the (235)U/(238)U ratio was also fairly homogeneous and within the natural range. The chemistry of the tree bark samples closely reflected that of the soils, with some notable exceptions. Unlike the soils, some tree bark samples had anomalous values of the (235)U/(238)U ratio due to mixing of depleted uranium (DU) with the natural uranium pool. Moreover, the distribution of some trace elements (such as REEs, Th and Zr) and the isotopic composition of Pb in barks clearly differed from those of the nearby soils. The overall results suggested that significant external inputs occurred implying that once formed the DU-enriched particles could travel over long distances. The polycyclic aromatic hydrocarbon concentrations in tree bark samples showed that phenanthrene, fluoranthene and pyrene were the most abundant components, indicating an important role of automotive traffic. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Evaluation and compilation of fission product yields 1993

    Energy Technology Data Exchange (ETDEWEB)

    England, T.R.; Rider, B.F.

    1995-12-31

    This document is the latest in a series of compilations of fission yield data. Fission yield measurements reported in the open literature and calculated charge distributions have been used to produce a recommended set of yields for the fission products. The original data with reference sources, and the recommended yields axe presented in tabular form. These include many nuclides which fission by neutrons at several energies. These energies include thermal energies (T), fission spectrum energies (F), 14 meV High Energy (H or HE), and spontaneous fission (S), in six sets of ten each. Set A includes U235T, U235F, U235HE, U238F, U238HE, Pu239T, Pu239F, Pu241T, U233T, Th232F. Set B includes U233F, U233HE, U236F, Pu239H, Pu240F, Pu241F, Pu242F, Th232H, Np237F, Cf252S. Set C includes U234F, U237F, Pu240H, U234HE, U236HE, Pu238F, Am241F, Am243F, Np238F, Cm242F. Set D includes Th227T, Th229T, Pa231F, Am241T, Am241H, Am242MT, Cm245T, Cf249T, Cf251T, Es254T. Set E includes Cf250S, Cm244S, Cm248S, Es253S, Fm254S, Fm255T, Fm256S, Np237H, U232T, U238S. Set F includes Cm243T, Cm246S, Cm243F, Cm244F, Cm246F, Cm248F, Pu242H, Np237T, Pu240T, and Pu242T to complete fission product yield evaluations for 60 fissioning systems in all. This report also serves as the primary documentation for the second evaluation of yields in ENDF/B-VI released in 1993.

  12. 234U/238U Disequilibrium along stylolitic discontinuities in deep Mesozoic limestone formations of the Eastern Paris basin: evidence for discrete uranium mobility over the last 1–2 million years

    Directory of Open Access Journals (Sweden)

    P. Deschamps

    2004-01-01

    Full Text Available The (234U/238 equilibrium state of borehole core samples from the deep, low-permeability limestone formations surrounding the target argilite layer of the Meuse/Haute-Marne experimental site of the French agency for nuclear waste management -ANDRA- (Agence nationale pour la gestion des déchets radioactifs was examined to improve understanding of naturally occurring radionuclide behaviour in such geological settings. Highly precise, accurate MC-ICP-MS measurements of the (234U/238U activity ratio show that limestone samples characterised by pressure dissolution structures (stylolites or dissolution seams display systematic (234U/238U disequilibria, while the pristine carbonate samples remain in the secular equilibrium state. The systematic feature is observed throughout the zones marked by pressure dissolution structures: (i the material within the seams shows a deficit of 234U over 238U ((234U/238U down to 0.80 and (ii the surrounding carbonate matrix is characterised by an activity ratio greater than unity (up to 1.05. These results highlight a centimetric-scale uranium remobilisation in the limestone formations along these sub-horizontal seams. Although their nature and modalities are not fully understood, the driving processes responsible for these disequilibria were active during the last 1–2 Ma. Keywords: uranium isotopes, multiple-collector ICP-MS, waste management, remobilisation, migration

  13. Decay of Bk246* formed in similar entrance channel reactions of B11+U235 and N14+Th232 at low energies using the dynamical cluster-decay model

    Science.gov (United States)

    Singh, Birbikram; Sharma, Manoj K.; Gupta, Raj K.

    2008-05-01

    The decay of the Bk246* nucleus, formed in entrance channel reactions B11+U235 and N14+Th232 at different incident energies, is studied by using the dynamical cluster-decay model (DCM) extended to include the deformations and orientations of nuclei. The main decay mode here is fission. The other (weaker) decay channels are the light particles evaporation (A⩽4) and intermediate mass fragments (5⩽A⩽20). All decay products are calculated as emissions of preformed clusters through the interaction barriers. The calculated fission cross sections σfiss, taken as a sum of the energetically favored symmetric and near symmetric fragments (ACN/2±7 and A=106-110 plus complementary fragments) show an excellent agreement with experimental data at all experimental incident c.m. energies for both reactions, except for the top three energies in the case of the B11+U235 reaction. The disagreement between the DCM calculations and data at higher incident c.m. energies for the B11+U235 entrance channel is associated with the presence of additional effects of noncompound, quasifission (qf) components, in contradiction with the measured anisotropy effects which indicate the other entrance channel N14+Th232 to contain the noncompound nucleus contribution. The prediction of two fission windows, the symmetric fission (SF) and near symmetric or heavy mass fragments (HMFs), suggests the presence of a fine structure of fission fragments, which also need an experimental verification. The only parameter of the model is the neck length parameter ▵R whose value is shown to depend strongly on limiting angular momentum, which in turn depends on the use of sticking or nonsticking moment of inertia for angular momentum effects.

  14. 234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California, USA

    Science.gov (United States)

    Drexler, Judith Z.; Paces, James B.; Alpers, Charles N.; Windham-Myers, Lisamarie; Neymark, Leonid; Bullen, Thomas D.; Taylor, Howard E.

    2013-01-01

    The purpose of this study was to determine the history of paleosalinity over the past 6000+ years in the Sacramento-San Joaquin Delta (the Delta), which is the innermost part of the San Francisco Estuary. We used a combination of Sr and U concentrations, d87Sr values, and 234U/238U activity ratios (AR) in peat as proxies for tracking paleosalinity. Peat cores were collected in marshes on Browns Island, Franks Wetland, and Bacon Channel Island in the Delta. Cores were dated using 137Cs, the onset of Pb and Hg contamination from hydraulic gold mining, and 14C. A proof of concept study showed that the dominant emergent macrophyte and major component of peat in the Delta, Schoenoplectus spp., incorporates Sr and U and that the isotopic composition of these elements tracks the ambient water salinity across the Estuary. Concentrations and isotopic compositions of Sr and U in the three main water sources contributing to the Delta (seawater, Sacramento River water, and San Joaquin River water) were used to construct a three-end-member mixing model. Delta paleosalinity was determined by examining variations in the distribution of peat samples through time within the area delineated by the mixing model. The Delta has long been considered a tidal freshwater marsh region, but only peat samples from Franks Wetland and Bacon Channel Island have shown a consistently fresh signal (Browns Island) has alternated between fresh and oligohaline (0.5-5 ppt).

  15. Energy dependence of fission product yields from 235U, 238U, and 239Pu with monoenergetic neutrons between thermal and 14.8 MeV

    Science.gov (United States)

    Gooden, Matthew; Arnold, Charles; Bhike, Megha; Bredeweg, Todd; Fowler, Malcolm; Krishichayan; Tonchev, Anton; Tornow, Werner; Stoyer, Mark; Vieira, David; Wilhelmy, Jerry

    2017-09-01

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements has been performed. The energy dependence of a number of cumulative fission product yields (FPY) have been measured using quasi-monoenergetic neutron beams for three actinide targets, 235U, 238U and 239Pu, between 0.5 and 14.8 MeV. The FPYs were measured by a combination of fission counting using specially designed dual-fission chambers and γ-ray counting. Each dual-fission chamber is a back-to-back ionization chamber encasing an activation target in the center with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activation target with no reference to the fission cross-section, thus reducing uncertainties. γ-ray counting of the activation target was performed on well-shielded HPGe detectors over a period of two months post irradiation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 3.6, 4.6, 5.5, 7.5, 8.9 and 14.8 MeV. Preliminary results from thermal irradiations at the MIT research reactor will also be presented and compared to present data and evaluations. This work was performed under the auspices of the U.S. Department of Energy by Los Alamos National Security, LLC under contract DE-AC52-06NA25396, Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344 and by Duke University and Triangle Universities Nuclear Laboratory through NNSA Stewardship Science Academic Alliance grant No. DE-FG52-09NA29465, DE-FG52-09NA29448 and Office of Nuclear Physics Grant No. DE-FG02-97ER41033.

  16. Evolution of groundwater chemistry in coastal aquifers of the south-eastern White Sea area (NW Russia) using14C and234U-238U dating.

    Science.gov (United States)

    Malov, A I

    2018-03-01

    The specific objectives of the study are to clarify the sources and characteristics of groundwater in the aquifers along the coast of the White Sea in northwestern Russia, and on this basis to perform a broad 14 C and 234 U/ 238 U dating of all their types, taking into account the mixing processes. Investigation of an evolution of the groundwater chemistry revealed that the main evolutionary trends are the following: (1) Mixing Late Pleistocene brackish water end member (brackish1) and Mikulino seawater end member with strongly brackish and salty water in the Vpd aquifer (salty Vpd) formation. Groundwater dating showed the "brackish1" residence time in the aquifer of 32.96±2.3ka. Recharge of "brackish1" could have occurred in MIS 3. (2) Mixing Late Pleistocene freshwater end member (fresh LP) and "salty Vpd" end member with brackish water (brackish2) formation. Groundwater dating showed the "brackish2" residence time in the aquifer from 25.1±0.7 to 39.2±6.3ka. Recharge of "fresh LP" could have occurred ~ in MIS 3 also. (3) Mixing Middle Pleistocene-Holocene freshwater of melting glaciers (fresh MP-H) end member and brine end member with the strongly brackish and salty water in Vmz aquifer (salty Vmz) formation. Recharge of "fresh MP-H" could have occurred in Middle Pleistocene-Holocene during MIS 12-MIS 1. As a result of intensive and rapid recharge after the glacial melting, glacial fluids have penetrated at depth to >200m. The results of this study provide a better understanding of the interrelationship of various groundwater flows near the coasts and contribute to a more justified and efficient use of them for drinking water supply in large cities, balneological treatment and industrial extraction of iodine waters. They also allow assessment of the risks of dumping saline drainage water into the environment. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. CREATING THE KULTUK POLYGON FOR EARTHQUAKE PREDICTION: VARIATIONS OF (234U/238U AND 87SR/86SR IN GROUNDWATER FROM ACTIVE FAULTS AT THE WESTERN SHORE OF LAKE BAIKAL

    Directory of Open Access Journals (Sweden)

    S. V. Rasskazov

    2015-01-01

    Full Text Available Introduction. Determinations of (234U/238U in groundwater samples are used for monitoring current deformations in active faults (parentheses denote activity ratio units. The cyclic equilibrium of activity ratio 234U/238U≈≈(234U/238U≈γ≈1 corresponds to the atomic ratio ≈5.47×10–5. This parameter may vary due to higher contents of 234U nuclide in groundwater as a result of rock deformation. This effect discovered by P.I. Chalov and V.V. Cherdyntsev was described in [Cherdyntsev, 1969, 1973; Chalov, 1975; Chalov et al., 1990; Faure, 1989]. In 1970s and 1980s, only quite laborious methods were available for measuring uranium isotopic ratios. Today it is possible to determine concentrations and isotopic ration of uranium by express analytical techniques using inductively coupled plasma mass spectrometry (ICP‐MS [Halicz et al., 2000; Shen et al., 2002; Cizdziel et al., 2005; Chebykin et al., 2007]. Sets of samples canbe efficiently analysed by ICP‐MS, and regularly collected uranium isotope values can be systematized at a new quality level for the purposes of earthquake prediction. In this study of (234U/238U in groundwater at the Kultuk polygon, we selected stations of the highest sensitivity, which can ensure proper monitoring of the tectonic activity of the Obruchev and Main Sayan faults. These two faults that limit the Sharyzhalgai block of the crystalline basement of the Siberian craton in the south are conjugated in the territory of the Kultuk polygon (Fig 1. Forty sets of samples taken from 27 June 2012 to 28 January 2014 were analysed, and data on 170 samples are discussed in this paper.Methods. Isotope compositions of uranium and strontium were determined by methods described in [Chebykin et al., 2007; Pin et al., 1992] with modifications. Analyses of uranium by ISP‐MS technique were performed using an Agilent 7500ce quadrapole mass spectrometer of the Ultramicroanalysis Collective Use Centre; analyses of

  18. Temporal and Petrogenetic Constraints on Volcanic Accretionary Processes at 9-10 Degrees North East Pacific Rise

    Science.gov (United States)

    2010-06-01

    Sims, S. Weyer , and J. Schweiters (2008), Measurement of 234U/238U and 230Th/232Th in volcanic rocks using the Neptune PIMMS, J. Anal. At. Spectrom...doi:10.1029/2002GC000419. Ball, L., K. Sims, S. Weyer , and J. Schweiters (2008), Measurement of 234U/238U and 230Th/232Th in volcanic rocks using

  19. A year-by-year record of 236-U/238-U in coral as a step towards establishing 236-U from nuclear weapons testing fall-out as oceanic tracer

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Stephan; Steier, Peter [University of Vienna, Faculty of Physics, Vienna (Austria); Carilli, Jessica [Australian Nuclear Science and Technology Organisation, Lucas Heights (Australia)

    2012-07-01

    Since uranium is known to behave conservatively in ocean waters, 236-U has great potential in application as oceanic tracer. 236-U (t1/2=23.4 Ma) was introduced into the oceans by atmospheric nuclear weapon testing with amount estimates ranging from 700 kg to 1500 kg. Thus a resulting initial average 236-U/238-U ratio of at least 5e-9 is expected for an oceanic mixed layer depth of 100 m. This ratio is already higher than the natural pre-nuclear background, which is expected to be at 10e-14 levels. Even the elevated ratios of global stratospheric fall-out are beyond the capabilities of ICPMS and TIMS methods. However, the exceptional sensitivity and ultra-low background for 236-U of the Vienna Environmental Research Accelerator's Accelerator Mass Spectrometry system allows us to measure down to 10-13 detection limits. We present a year-by-year record of 236-U/238-U for a Caribbean coral core covering years 1944 to 2006, thus allowing to us put constraints on the oceanic input of 236-U by atmospheric testing. Moreover modeling of the results also demonstrates the capabilities of 236-U as oceanic tracer.

  20. Systems Requirement Document for the MSRE U-233 Conversion System

    Energy Technology Data Exchange (ETDEWEB)

    Aigner, R.D.

    2001-01-11

    The fissile material reclamation activities for the MSRE remediation project include the removal and recovery of uranium from the off-gas system, from the stored fuel salt, and finally, from the uranium-laden charcoal in the Auxiliary Charcoal Bed (ACB). Each of these operations produces an uranium/fluoride compound that is not suitable for long-term storage. The uranium-fluoride compounds can be stored for a limited period of time in pressure vessels. The interim-storage vessels are designed to handle the internal pressure buildup from gases formed by radiolysis of the uranium-fluoride compounds. The conversion process will take the pressurized vessels from interim storage and process the materials in a hot cell located at Building 4501. The gas in the vessels will be vented through chemical traps and then the traps will be processed to convert the various uranium-fluoride compounds to a stable uranium oxide form. This will be done one trap at a time. The chemical form of uranium being extracted from the off-gas system and from fuel salt fluorination process is uranium hexafluoride UF{sub 6}. During the operations at MSRE, the UF{sub 6} is chemisorbed onto sodium fluoride (NaF) traps where it forms the complex, 2NaF{center_dot}UF{sub 6}. The conversion process that will be installed in the Building 4501 Hot Cell D will recover the UF{sub 6} from the NaF traps by decomposition of the binary complex at elevated temperatures (>300 C). After the uranium is extracted from the NaF traps, it is collected in the conversion process reaction vessel. The reaction vessel is then hydrolized and heated through several step operations up to 900 C in order to convert the material to a stable uranium oxide. The ACB at MSRE contains uranium-laden charcoal with unstable C{sub x}F compounds. After extraction at MSRE, this material will be delivered to Building 4501 Hot Cell D for processing to a stable oxide. The charcoal conversion process is still under development, with mockup and full scale testing of the proposed flow sheet funded in FY 99 and FY 00. The uranium-laden charcoal has been pre-treated with ammonia to prevent the deflagration of the C{sub x}F if localized heating (>{approximately}150 C) occurs during the charcoal removal process. Prior to removal, the treatment will be performed a second time to denature the 1 to 5% reformation of C{sub x}F that has occurred due to radiolysis of NH{sub 4}F. The uranium-laden charcoal will be physically extracted and stored in several pressure vessels at MSRE until the conversion process is designed and installed in Hot Cell A in Building 4501.

  1. Ojo Joshua (19)

    African Journals Online (AJOL)

    DELL

    Permanent Address: Department of Physics and Engineering Physics, Obafemi Awolowo University, Ile-Ife 220001,. Osun State, Nigeria. (Corresponding Author: jojo@oauife.edu.ng) th th. (Received: 6 Aug. ... Specific activities of the naturally- occurring radioactive series U-238, Th-232 and K-40 were determined, after the ...

  2. Certified reference material for radionuclides in fish flesh sample IAEA-414 (mixed fish from the Irish Sea and North Sea)

    DEFF Research Database (Denmark)

    Pham, M.K.; Sanchez-Cabeza, J.A.; Povinec, P.P.

    2006-01-01

    A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides (K-40, Cs-137, Th-232, U-234, U-235, U-238, Pu-238, Pu239+240 and Am-241) were ...

  3. Preliminary analyses of natural radionuclides in selected Turkish power plant lignites

    Energy Technology Data Exchange (ETDEWEB)

    Ozturk, N.; Ozdogan, Z.S. [Cekmece Nuclear Research & Training Center, Istanbul (Turkey). Dept. of Chemistry

    2004-07-01

    This preliminary study presents the experimental results concerning the concentrations of selected radionuclides (K-40, U-238, Ra-226, Th-232) in Afsin-Elbistan, Can, Cayirhan, Erzurum, Goynuk, Kangal, Orhaneli, Saray, Seyitomer, Soma, Tuncbilek, Yatagan and Yenikoy lignites, which are primarily utilized as fuel for thermal power plants in Turkey. Gamma-spectrometry of 39 representative lignite samples gave results with the following concentration ranges: 8 to 296 Bq/kg for U-238, 3 to 79 Bq/kg for Th-232, 17 to 360 Bq/kg for K-40, and 5 to 130 Bq/kg for Ra-226. The U-238 results reported here are higher than other literature values for various world coals, earth's crust and world average.

  4. On the use of a molten salt fast reactor to apply an idealized transmutation scenario for the nuclear phase out.

    Science.gov (United States)

    Merk, Bruno; Rohde, Ulrich; Glivici-Cotruţă, Varvara; Litskevich, Dzianis; Scholl, Susanne

    2014-01-01

    In the view of transmutation of transuranium (TRU) elements, molten salt fast reactors (MSFRs) offer certain advantages compared to solid fuelled reactor types like sodium cooled fast reactors (SFRs). In the first part these advantages are discussed in comparison with the SFR technology, and the research challenges are analyzed. In the second part cycle studies for the MSFR are given for different configurations--a core with U-238 fertile, a fertile free core, and a core with Th-232 as fertile material. For all cases, the transmutation potential is determined and efficient transmutation performance for the case with thorium as a fertile material as well as for the fertile free case is demonstrated and the individual advantages are discussed. The time evolution of different important isotopes is analyzed. In the third part a strategy for the optimization of the transmutation efficiency is developed. The final aim is dictated by the phase out decision of the German government, which requests to put the focus on the determination of the maximal transmutation efficiency and on an as much as possible reduced leftover of transuranium elements at the end of the reactor life. This minimal leftover is achieved by a two step procedure of a first transmuter operation phase followed by a second deep burning phase. There the U-233, which is bred in the blanket of the core consisting of thorium containing salt, is used as feed. It is demonstrated, that transmutation rates up to more than 90% can be achieved for all transuranium isotopes, while the production of undesired high elements like californium is very limited. Additionally, the adaptations needed for the simulation of a MSFR, and the used tool HELIOS 1.10 is described.

  5. Analysis on fuel breeding capability of FBR core region based on minor actinide recycling doping

    Science.gov (United States)

    Permana, Sidik; Novitrian, Waris, Abdul; Ismail, Suzuki, Mitsutoshi; Saito, Masaki

    2014-09-01

    Nuclear fuel breeding based on the capability of fuel conversion capability can be achieved by convertion rasio of some fertile materials into fissile materials during nuclear reaction processes such as main fissile materials of U-233, U-235, Pu-239 and Pu-241 and for fertile materials of Th-232, U-238, and Pu-240 as well as Pu-238. Minor actinide (MA) loading option which consists of neptunium, americium and curium will gives some additional contribution from converted MA into plutonium such as conversion Np-237 into Pu-238 and it's produced Pu-238 converts to Pu-239 via neutron capture. Increasing composition of Pu-238 can be used to produce fissile material of Pu-239 as additional contribution. Trans-uranium (TRU) fuel (Mixed fuel loading of MOX (U-Pu) and MA composition) and mixed oxide (MOX) fuel compositions are analyzed for comparative analysis in order to show the effect of MA to the plutonium productions in core in term of reactor criticality condition and fuel breeding capability. In the present study, neptunium (Np) nuclide is used as a representative of MAin trans-uranium (TRU) fuel composition as Np-MOX fuel type. It was loaded into the core region gives significant contribution to reduce the excess reactivity in comparing to mixed oxide (MOX) fuel and in the same time it contributes to increase nuclear fuel breeding capability of the reactor. Neptunium fuel loding scheme in FBR core region gives significant production of Pu-238 as fertile material to absorp neutrons for reducing excess reactivity and additional contribution for fuel breeding.

  6. On the use of a molten salt fast reactor to apply an idealized transmutation scenario for the nuclear phase out.

    Directory of Open Access Journals (Sweden)

    Bruno Merk

    Full Text Available In the view of transmutation of transuranium (TRU elements, molten salt fast reactors (MSFRs offer certain advantages compared to solid fuelled reactor types like sodium cooled fast reactors (SFRs. In the first part these advantages are discussed in comparison with the SFR technology, and the research challenges are analyzed. In the second part cycle studies for the MSFR are given for different configurations--a core with U-238 fertile, a fertile free core, and a core with Th-232 as fertile material. For all cases, the transmutation potential is determined and efficient transmutation performance for the case with thorium as a fertile material as well as for the fertile free case is demonstrated and the individual advantages are discussed. The time evolution of different important isotopes is analyzed. In the third part a strategy for the optimization of the transmutation efficiency is developed. The final aim is dictated by the phase out decision of the German government, which requests to put the focus on the determination of the maximal transmutation efficiency and on an as much as possible reduced leftover of transuranium elements at the end of the reactor life. This minimal leftover is achieved by a two step procedure of a first transmuter operation phase followed by a second deep burning phase. There the U-233, which is bred in the blanket of the core consisting of thorium containing salt, is used as feed. It is demonstrated, that transmutation rates up to more than 90% can be achieved for all transuranium isotopes, while the production of undesired high elements like californium is very limited. Additionally, the adaptations needed for the simulation of a MSFR, and the used tool HELIOS 1.10 is described.

  7. On the Use of a Molten Salt Fast Reactor to Apply an Idealized Transmutation Scenario for the Nuclear Phase Out

    Science.gov (United States)

    Merk, Bruno; Rohde, Ulrich; Glivici-Cotruţă, Varvara; Litskevich, Dzianis; Scholl, Susanne

    2014-01-01

    In the view of transmutation of transuranium (TRU) elements, molten salt fast reactors (MSFRs) offer certain advantages compared to solid fuelled reactor types like sodium cooled fast reactors (SFRs). In the first part these advantages are discussed in comparison with the SFR technology, and the research challenges are analyzed. In the second part cycle studies for the MSFR are given for different configurations – a core with U-238 fertile, a fertile free core, and a core with Th-232 as fertile material. For all cases, the transmutation potential is determined and efficient transmutation performance for the case with thorium as a fertile material as well as for the fertile free case is demonstrated and the individual advantages are discussed. The time evolution of different important isotopes is analyzed. In the third part a strategy for the optimization of the transmutation efficiency is developed. The final aim is dictated by the phase out decision of the German government, which requests to put the focus on the determination of the maximal transmutation efficiency and on an as much as possible reduced leftover of transuranium elements at the end of the reactor life. This minimal leftover is achieved by a two step procedure of a first transmuter operation phase followed by a second deep burning phase. There the U-233, which is bred in the blanket of the core consisting of thorium containing salt, is used as feed. It is demonstrated, that transmutation rates up to more than 90% can be achieved for all transuranium isotopes, while the production of undesired high elements like californium is very limited. Additionally, the adaptations needed for the simulation of a MSFR, and the used tool HELIOS 1.10 is described. PMID:24690768

  8. Distribution of Th-232 and Th-228 in Santos and Sao Vicente Estuary, Sao Paulo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, P.S.C.; Mazzilli, B.P.; Favaro, D.I.T. [Instituto de Pesquisas Energeticas e Nucleares, Av. Lineu Prestes, 2242, Caixa Postal 05508-000, Cidade Universitaria, Sao Paulo (Brazil)]. e-mail: Pscsilva@ipen.br

    2004-07-01

    In the last decades considerable attention has been given to technologically enhanced natural occurring radioactive material (TENORM). Within this frame, of particular concern is the phosphate fertilizer industry. Santos Basin, located in Southwest Brazil, Sao Paulo State, comprising Santos and Sao Vicente estuarine system, is considered the most important industrial region of the country. Among the industrial activities present, phosphate fertilizer plants are responsible for the production of 69 millions tons of phosphogypsum waste, which is stockpiled in the surrounding environment. This waste concentrates radionuclides of the natural series originally present in the phosphate rock used as raw material. This study aims to evaluate the environmental impact of such activities in the sediments of the estuarine system. {sup 232} Th and {sup 228} Th concentrations in Santos and San Vicente estuary sediments were determined by Neutron activation analysis and Gamma spectrometry, respectively. {sup 232} Th concentration ranged from 6.5 to 198 Bq kg{sup -1} with mean value of 57 {+-} 39 Bq kg{sup -1}, for 42 samples. {sup 228} Th content varied from 12 to 110 Bq kg{sup -1} with a mean value of 74 {+-} 23 Bq kg{sup -1}, for 18 samples. It can be seen that the amount of {sup 232} Th is higher in the rivers close to the phosphogypsum piles, at least five points were identified as being affected by anthropogenic factor. (Author)

  9. Neutron-induced fission fragment angular distribution at CERN n TOF: The Th-232 case

    CERN Document Server

    Tarrio, Diego; Paradela, Carlos

    This thesis work was done in the frame of the study of the neutron-induced fission of actinides and subactinides at the CERN n TOF facility using a fast Parallel Plate Avalanche Counters (PPACs) setup. This experimental setup provide us with an intense neutron beam with a white spectrum from thermal to 1 GeV and with an outstanding high resolution provided by its flight path of 185 m. In our experiment, fission events were identified by detection of both fission fragments in time coincidence in the two PPAC detectors flanking the corresponding target. This technique allowed us to discriminate the fission events from the background produced by α disintegration of radioactive samples and by particles produced in spallation reactions. Because PPAC detectors are insensitive to the γ flash, it is possible to reach energies as high as 1 GeV. The stripped cathodes provide the spatial position of the hits in the detectors, so that the emission angle of the fission fragments can be measured. Inside the reaction cham...

  10. Adsorption of Cs-137 and U-238 in semi-arid soils; Adsorcion de Cs-137 y U-238 en suelos semiaridos

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez T, U. O. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, 52140 Metepec, Estado de Mexico (Mexico); Monroy G, F.; Anguiano A, J. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Fernandez R, E., E-mail: uohtrejo@gmail.com [Universidad Politecnica del Valle de Toluca, Carretera Toluca-Almoloya de Juarez Km. 5.6, Santiaguito Tlalcilalcali, Estado de Mexico (Mexico)

    2013-10-15

    Is of great importance to determine the adsorption properties of the soils where radioactive wastes are stored, fundamentally of the radioisotopes contained in these wastes, with the purpose of knowing like will be their behavior in the event of happening radionuclide migration toward the surrounding means. Therefore, in this work the adsorption properties of {sup 137}Cs{sup +} and {sup 238}UO{sub 2}{sup 2+} in soils coming from the Storage Center of Radioactive Wastes are studied. Was studied the effect of the soil type and the particle size of the soil in the adsorption properties of Cs (I) and U (Vi). 13 soil samples and six different particle sizes were analyzed. The adsorption studies were carried out by the radiotracers technique in static way. The results indicate an important adsorption affinity toward the Cs-137 and a very vulnerable affinity for the {sup 238}UO{sub 2}{sup 2+}. (author)

  11. Weathering and transport of sediments in the Bolivian Andes : time constraints from uranium-series isotopes

    OpenAIRE

    Dosseto, A.; Bourdon, B.; Gaillardet, J.; Maurice Bourgoin, Laurence; Allegre, C.J.

    2006-01-01

    Rivers from the upper Rio Madeira basin (Bolivia) have been studied with uranium-series isotopes in order to constrain the timescales of weathering and sediment transfer from the Andes through the Amazon tropical plain. Uranium (U), thorium, (Th) and radium (Ra) isotopes (U-238-U-234-Th-230-Ra-226 and Th-232) have been analyzed in the suspended load (> 0.2 mu m) of rivers. Increasing Th-230 excesses relative to U-238 in suspended particles from the Andes to the tropical plain is interpreted a...

  12. The European Expression Of Interest For High Purity U-233 Materials

    Energy Technology Data Exchange (ETDEWEB)

    Giaquinto, Joseph M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Younkin, James R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-04-01

    The purpose of this letter report is to document the response for an Expression of Interest (EOI) sent to the European Safeguards and research and development (R&D) scientific communities for the distribution of small amounts of high purity 233U materials for use in safeguards, nonproliferation, and basic R&D in the nuclear disciplines. The intent for the EOI was to gauge the level of international interest for these materials from government and research institutions with programmatic missions in the nuclear security or nuclear R&D arena. The information contained herein is intended to provide information to assist key decision makers in DOE as to the ultimate disposition path for the high purity materials currently being recovered at Oak Ridge National Laboratory (ORNL) and only those items for which there is no United States (U.S.) sponsor identified.

  13. Comparative assessment of natural radioactivity in fallout samples from Patras, and Megalopolis, Greece

    Energy Technology Data Exchange (ETDEWEB)

    Papaefthymiou, H.; Kritidis, P.; Anousis, J.; Sarafidou, J. [University of Patras, Patras (Greece). Dept. of Chemistry

    2005-07-01

    Bulk deposition samples were collected simultaneously from two Greek cities, Patras and Megalopolis, with different emission sources of natural radioactivity, on a monthly basis, during a whole year. Gross {beta}-activity and U-238- and Th-232-activities were determined in a total of 95 samples of deposited dust. The results were statistically analyzed in order to determine the natural radioactivity levels and their variations in the above cities. No significant difference was found in deposited dust amount between the two cities, while the values of gross {beta}- U-238- and Th-232-activities were about 3, 71 and 4 times higher in Megalopolis than in Patras, respectively. This was attributed to the operation of lignite power plants A and B in the vicinity of the city of Megalopolis, while natural radioactivity concentrations in Patras' fallout samples were of natural sources.

  14. Analysis of TPC Single Sextant U-238/U-235 Engineering In-Beam Data

    Energy Technology Data Exchange (ETDEWEB)

    Tony Hill

    2012-09-01

    The Time Projection Chamber is a collaborative effort to implement an innovative approach and deliver unprecedented fission measurements to DOE programs. This 4p- detector system will provide unrivaled 3-D data about the fission process. This TPC has been shipped and installed at LANSCE and is collecting further engineering data for the full system scale up next year.

  15. Distribution of U-235 and U-238 in food(II)

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yong Woo; Lee, Jeong Min; Oh, Hyun Kyun; Han, Man Joong [KORTIC, Taejon (Korea, Republic of)

    2004-02-15

    To accomplish the objective of this work, analyses of uranium concentration in 100 food samples (fruit and vegetables) were carried out. The surveillance results on uranium isotope concentrations in food of Korea will be used as a basis of estimating the annual effective dose to the public by uranium and a baseline data to establish a national recommend value for the protection from radiation of food.

  16. Beta decay heat following U-235, U-238 and Pu-239 neutron fission

    Science.gov (United States)

    Li, Shengjie

    1997-09-01

    This is an experimental study of beta-particle decay heat from 235U, 239Pu and 238U aggregate fission products over delay times 0.4-40,000 seconds. The experimental results below 2s for 235U and 239Pu, and below 20s for 238U, are the first such results reported. The experiments were conducted at the UMASS Lowell 5.5-MV Van de Graaff accelerator and 1-MW swimming-pool research reactor. Thermalized neutrons from the 7Li(p,n)7Be reaction induced fission in 238U and 239Pu, and fast neutrons produced in the reactor initiated fission in 238U. A helium-jet/tape-transport system rapidly transferred fission fragments from a fission chamber to a low background counting area. Delay times after fission were selected by varying the tape speed or the position of the spray point relative to the beta spectrometer that employed a thin-scintillator-disk gating technique to separate beta-particles from accompanying gamma-rays. Beta and gamma sources were both used in energy calibration. Based on low-energy(<1 MeV) internal-conversion electron studies, a set of trial responses for the spectrometer was established and spanned electron energies 0-10 MeV. Measured beta spectra were unfolded for their energy distributions by the program FERD, and then compared to other measurements and summation calculations based on ENDF/B-VI fission-product data performed on the LANL Cray computer. Measurements of the beta activity as a function of decay time furnished a relative normalization. Results for the beta decay heat are presented and compared with other experimental data and the summation calculations.

  17. Initial Eccentricity in Deformed 197Au+197Au and 238U+238U Collisions at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Filip, Peter; Lednicky, Richard; Masui, Hiroshi; Xu, Nu

    2010-07-07

    Initial eccentricity and eccentricity fluctuations of the interaction volume created in relativistic collisions of deformed {sup 197}Au and {sup 238}U nuclei are studied using optical and Monte-Carlo (MC) Glauber simulations. It is found that the non-sphericity noticeably influences the average eccentricity in central collisions and eccentricity fluctuations are enhanced due to deformation. Quantitative results are obtained for Au+Au and U+U collisions at energy {radical}s{sub NN} = 200 GeV.

  18. Determination of 235U/238U Ratio on Urine by ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Collins, L; Gobaleza, A; Langston, R; Radev, R; Than, C; Wong, C; Wood-Zika, A

    2011-10-19

    LLNL Internal Dosimetry Program - The new procedure satisfies the requirement to determine {sup 235}U/{sup 238}U ratio in bioassay urine samples. MDA - The L{sub C} and MDA{sub 95} for {sup 235}U are well below the required detection limit of 0.00035 {mu}g/L. Turn around time - Analysis of 10 samples plus 2 QCs can be completed in one work day (8 hours).

  19. Reaction paths and host phases of uranium isotopes (235U; 238U), Saanich Inlet

    Science.gov (United States)

    Amini, M.; Holmden, C. E.; Francois, R. H.

    2009-12-01

    In recent times, Uranium has become increasingly the focus of stable isotope fractionation studies. Variations in 238U/235U have been reported as a result of redox reactions [1,2] from the nuclear field shift effect [3], and a mass-dependent, microbially-mediated, kinetic isotope effect [4]. The 238U/235U variability caused by changes in environmental redox conditions leads to an increase in the 238U/235U ratios of the reduced U species sequestered into marine sediments. This points to U isotope variability as a new tool to study ancient ocean redox changes. However, the process by which reduced sediments become enriched in the heavy isotopes of U is not yet known, and hence the utility of 238U/235U as a redox tracer remains to be demonstrated. In order to further constrain sedimentary U enrichment and related isotope effect, we are investigating U isotopic compositions of water samples and fresh surface sediment grab samples over a range of redox conditions in the seasonally anoxic Saanich Inlet, on the east coast of Vancouver Island. U was sequentially extracted from sediments in order to characterize specific fractions for their isotopic composition. The measurements were carried out by MC-ICPMS using 233U/236U-double spike technique. The data are reported as δ238U relative to NBL 112a with a 238U/235U ratio of 137.88 (2sd). External precision is better than 0.10‰ (2sd). Fifteeen analyses of seawater yielded δ238U of -0.42±0.08‰ (2sd). The results for the water samples indicate a homogenous δ238U value throughout the Saanich Inlet water column that matches the global seawater signature. All of the water samples from above and below average -0.42±0.05‰ (2sd). In contrast, a plankton net sample yielded a distinctly different, (about 0.5‰ lighter) isotope value. Bacterial reduction experiments [4] have also shown isotope enrichment factors of about -0.3‰. In addition, metal isotope fractionation occurs during adsorption with the light isotope being preferentially adsorbed [5]. Whether plankton mediated chemical reduction or scavenging causes this fractionation will be further investigated by leaching experiments on sediment trap samples. By contrast, weak acidic leachates (at pH 6) of suboxic bottom sediments, tend towards higher δ238U values. For oxic sediments, U contents of this fraction were below detection limit. Stronger leaching at pH 3 removed most of the uranium from suboxic and oxic sediments. For oxic sediments, this fraction yields the seawater δ238U signature, while the U released from the suboxic sample is about 0.2‰ heavier. This matches the value for previously reported bulk analyses of suboxic sediments [1] implying that the reduced sedimentary U is released by this treatment,. Major and trace element analyses and XRD patterns will help relating this fraction to a specific mineral or reactive phase. [1] Weyer et al. (2007) GCA 72, 345-399. [2] Stirling et al. (2007) EPSL 264, 208-225. [3] Schauble (2007) GCA 71, 2170-2189. [4] Rademacher et al. (2006) Environ. Sci. Technol. 40,6943-6948. [5] Wasylenki (2009) GCA A1419.

  20. Validation of the U-238 inelastic scattering neutron cross section through the EXCALIBUR dedicated experiment

    Science.gov (United States)

    Leconte, Pierre; Bernard, David

    2017-09-01

    EXCALIBUR is an integral transmission experiment based on the fast neutron source produced by the bare highly enriched fast burst reactor CALIBAN, located in CEA/DAM Valduc (France). Two experimental campaigns have been performed, one using a sphere of diameter 17 cm and one using two cylinders of 17 cm diameter 9 cm height, both made of metallic Uranium 238. A set of 15 different dosimeters with specific threshold energies have been employed to provide information on the neutron flux attenuation as a function of incident energy. Measurements uncertainties are typically in the range of 0.5-3% (1σ). The analysis of these experiments is performed with the TRIPOLI4 continuous energy Monte Carlo code. A calculation benchmark with validated simplifications is defined in order to improve the statistical convergence under 2%. Various 238U evaluations have been tested: JEFF-3.1.1, ENDF/B-VII.1 and the IB36 evaluation from IAEA. A sensitivity analysis is presented to identify the contribution of each reaction cross section to the integral transmission rate. This feedback may be of interest for the international effort on 238U, through the CIELO project.

  1. Influence of moderator to fuel ratio (MFR) on burning thorium in a subcritical assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wojciechowski, Andrzej, E-mail: andrzej.wojciechowski@ncbj.gov.pl [National Center for Nuclear Research, Otwock-Swierk (Poland); Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2014-10-15

    The conversion ratio (CR) of Th-232 to U-233 calculation results for a subcritical reactor assembly is presented as a function of MFR, burnup, power density (PD) and fissile concentration. The calculated model is based on subcritical assembly which makes configuration of fuel rods and volumes of moderator and coolant changes possible. This comfortable assembly enables investigation of CR in a thorium cycle for different value of MFR. Additionally, the calculation results of U-233 saturation concentration are explained by mathematical model. The value of MFR main influences the saturation concentration of U-233 and fissile and the fissile concentration dependence of CR. The saturation value of CR is included in the range CR ∈ (0.911, 0.966) and is a slowly increasing function of MFR. The calculations were done with a MCNPX 2.7 code.

  2. The quest for narrow e{sup +}e{sup -} cumulative energy distributions heavy ion collisions. The GSI e{sup +}e{sup -} puzzle; Die Suche nach schmalen e{sup +}e{sup -} Summenenergieverteilungen in Schwerionenkollisionen. Das GSI e{sup +}e{sup -}-Puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Ganz, R.

    1995-12-01

    The examination of electron-positron pairs which are emitted in heavy-ion collisions at the Coulomb barrier was continued with the newly designed EPoS II spectrometer at the UNILAC accelerator. The objective of the experiments was to further analyse the narrow line structures in the positron-electron cumulative energy distributions, which were observed in preceding measurements examining the collision systems U 238 + Th 232 and U 238 + Ta181 with the EPOS I spectrometer. By means of a reproduction experiment, the existence of the lines was statistically verified relying on a large data pool. [Deutsch] Die Untersuchung von Elektron- Positron Paaren, die bei Schwerionenkol lisionen an der Coulombbarriere emittiert werden, wurde mit dem neu kon zipierten EPoS II Spektrometer am UNILAC- Beschleuniger fortgesetzt. D ie Motivation der Experimente war die weitere Untersuchung der schmale n Linienstrukturen in den Positron- Elektron- Summenenergieverteilunge n, die in vorangegangenen Messungen der Stosssysteme U 238+ Th 232 un d U 238+ Ta 181 mit dem EPOS I Spektrometer beobachtet wurden. Durch ei ne Reproduktion wurde die Existenz der Linien anhand einer grossen Date nmenge statistisch sicher geprueft.

  3. Разработка Култукского сейсмопрогностического полигона: вариации ( 234U/ 238U) и 87Sr/ 86Sr в подземных водах из активных разломов западного побережья Байкала

    OpenAIRE

    РАССКАЗОВ СЕРГЕЙ ВАСИЛЬЕВИЧ; ЧЕБЫКИН ЕВГЕНИЙ ПАВЛОВИЧ; ИЛЬЯСОВА АЙГУЛЬ МАРАТОВНА; ВОДНЕВА ЕЛЕНА НИКОЛАЕВНА; ЧУВАШОВА ИРИНА СЕРГЕЕВНА; БОРНЯКОВ СЕРГЕЙ АЛЕКСАНДРОВИЧ; СЕМИНСКИЙ АЛЕКСАНДР КОНСТАНТИНОВИЧ; СНОПКОВ СЕРГЕЙ ВИКТОРОВИЧ; ЧЕЧЕЛЬНИЦКИЙ ВЛАДИМИР ВАСИЛЬЕВИЧ; ГИЛЁВА НАДЕЖДА АЛЕКСЕЕВНА

    2015-01-01

    Введение. Для отслеживания текущих деформаций в зонах активных разломов перспективны определения ( 234U/ 238U) в подземных водах (скобки обозначают единицы активности). Циклическое равновесие отношения активностей 234U/ 238U≈( 234U/ 238U)≈γ≈1 соответствует атомному отношению ≈5.47×10 -5. Вариации этого параметра могут быть обусловлены эффектом Чалова-Чердынцева обогащением подземных вод нуклидом 234U в результате деформаций пород [ Cherdyntsev, 1969, 1973; Chalov, 1975; Chalov et al., 1990; F...

  4. Revisiting the U-238 thermal capture cross section and gamma-raymission probabilities from Np-239 decay

    Energy Technology Data Exchange (ETDEWEB)

    Trkov, A.; Molnar, G.L.; Revay, Zs.; Mughabghab, S.F.; Firestone,R.B.; Pronyaev, V.G.; Nichols, A.L.; Moxon, M.C.

    2005-03-03

    The precise value of the thermal capture cross section of238U is uncertain, and evaluated cross sections from various sourcesdiffer by more than their assigned uncertainties. A number of theoriginal publications have been reviewed to assess the discrepant data,corrections were made for more recent standard cross sections andotherconstants, and one new measurement was analyzed. Due to the strongcorrelations in activation measurements, the gamma-ray emissionprobabilities from the beta decay of 239Np were also analyzed. As aresult of the analysis, a value of 2.683 +- 0.012 barns was derived forthe thermal capture cross section of 238U. A new evaluation of thegamma-ray emission probabilities from 239Np decay was alsoundertaken.

  5. Internal tides and sediment dynamics in the deep sea-Evidence from radioactive Th-234/U-238 disequilibria

    Energy Technology Data Exchange (ETDEWEB)

    Turnewitsch, R. [Scottish Assoc Marine Sci, Dunstaffnage Marine Lab, Oban PA37 1QA, Argyll (United Kingdom); Turnewitsch, R.; Waniek, J.J. [Balt Sea Res Inst Warnemunde, D-18119 Rostock (Germany); Reyss, J.L. [Lab Sci Climat and Environm, F-91198 Gif Sur Yvette (France); Nycander, J. [Stockholm Univ, Dept Meteorol, S-10691 Stockholm (Sweden); Lampitt, R.S. [Natl Oceanog Ctr, Southampton SO14 3ZH, Hants (United Kingdom)

    2008-07-01

    Residual flow, baro-tropic tides and internal (baro-clinic) tides interact in a number of ways with kilometer-scale sea floor topography such as abyssal hills and sea mounts. Because of their likely impact on vertical mixing such interactions are potentially important for ocean circulation and the mechanisms and the geometry of these interactions are a matter of ongoing studies. In addition, very little is known about how these interactions are reflected in the sedimentary record. This multi-year study investigates if flow/topography interactions are reflected in distributional patterns of the natural short-lived (half-life: 24.1 d) particulate-matter tracer {sup 234}Th relative to its conservative (non-particle-reactive) and very long-lived parent nuclide {sup 238}U. The sampling sites were downstream of, or surrounded by, fields of short sea mounts and, therefore, very likely to be influenced by nearby flow/topography interactions. At the sampling sites between about 200 and 1000 m above the sea floor recurrent 'fossil' disequilibria were detected. 'Fossil' disequilibria are defined by clearly detectable {sup 234}Th/{sup 238}U disequilibria (total {sup 234}Th radioactivity {<=}{sup 238}U radioactivity, indicating a history of intense particulate {sup 234}Th scavenging and particulate-matter settling from the sampled parcel of water) and conspicuously low particle-associated {sup 234}Th activities. 'Fossil' disequilibria were centered at levels in the water column that correspond to the average height of the short sea mounts near the sampling sites. This suggests the 'fossil' disequilibria are formed on the sea mount slopes. Moreover, the magnitude of the 'fossil' disequilibria suggests that the slopes of the short sea mounts in the study region are characterized by particularly vigorous fluid dynamics. Since 'fossil' disequilibria already occurred at {approx} O (1-10 km) away from the sea mount slopes it is likely that these vigorous fluid dynamics rapidly decay away from the slopes on scales of O (1-10 km). These conclusions are supported by the horizontal distribution and magnitude of the modeled total (baro-tropic + baro-clinic) tidal current velocities of the predominating tidal M{sub 2} constituent: on (near-)critical sea mount slopes baro-clinic tides lead to localized [{approx} O (1 km)] increases of the overall tidal current velocity by a factor of {approx} 2, thereby pushing the total current velocity well above the threshold for sediment erosion. The results of this and a previous study show that kilometer-scale flow/topography interactions leave a marine geochemical imprint.This imprint may help develop new sediment proxies for there construction of past changes of fluid dynamics in the deep sea, including residual and tidal flow. Sedimentary records controlled by kilometer-scale sea floor elevations are promising systems for there construction of paleo-changes of deep-ocean fluid dynamics. For the sediment-based reconstruction of paleo-parameters other than physical oceanographic ones it may be advisable to avoid kilometer-scale topography altogether. (authors)

  6. Natural radioisotopes. The ''atomic clock'' for the age determination of rocks and archeological discoveries; Natuerliche Radioisotope. Die ''Atomuhr'' fuer die Bestimmung des absoluten Alters von Gesteinen und archaeologischen Funden

    Energy Technology Data Exchange (ETDEWEB)

    Heuel-Fabianek, Burkhard [Forschungszentrum Juelich (Germany)

    2017-04-01

    The contribution describes the fundamentals of radiometric age determination based on natural radionuclides. Organic (carbon containing) materials can be dated up to an age of 60.000 years using C-14. The methods used for radiometric dating of rocks and minerals include the radioactive decay series of U-238, U-235, Th -232, but also the beta decay of Rb-87 to Sr-87 or K-40 to Ar-40. The absolute age of rocks is not necessarily identical with the radiometric dating result, since geological processes could influence the radionuclide ratio.

  7. Evaluation of Ra-226, Th-232 and K-40 activities concentrations and radium equivalent index in several Brazilian economic wall paints

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Leandro M.; Pecequilo, Brigitte R.S., E-mail: lmfonseca@ipen.br, E-mail: brigitte@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The titanium dioxide used as the white pigment in paints is produced from the processing of ilmenite minerals. As monazite, the main ilmenite radioactive contaminant, contains 1 to 20% thorium dioxide and also some uranium traces, so, eventually, wall paints can contain radioactivity. Activity concentrations of the naturally occurring radionuclides {sup 226}Ra, {sup 232}Th and {sup 40}K were determined in 15 Brazilian economic wall paints samples, by high resolution gamma-ray spectrometry. The activities concentrations in the studied samples ranged from 1.3 ± 0.2 Bq/kg to 23.4 ± 0.7 Bq/kg for {sup 226}Ra; from 2.5 ± 0.4 Bq/kg to 45.8 ± 1.5 Bq/kg for {sup 232}Th and from 5.8 ± 2.1 Bq/kg to 157 ± 22 Bq/kg for {sup 40}K. The radium equivalent index, calculated from the {sup 226}Ra, {sup 232}Th and {sup 40}K concentrations, varied from 1.30 Bq/kg up to 95.9 Bq/kg, below the value of 370 Bq/kg recommended by OECD for a safety use in residential building applications. (author)

  8. Natural radioactivity in rocks from Paraiba Sertao, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Damascena, Kennedy F.R.; Santos Junior, Jose A. dos; Amaral, Romilton dos S.; Bezerra, Jairo D.; Rojas, Lino V.; Medeiros, Nilson V. da S.; Silva, Alberto A. da; Santos, Josineide M. do N.; Santos Junior, Otavio P. dos, E-mail: kennedy.eng.ambiental@gmail.com, E-mail: jaraujo@ufpe.br, E-mail: romilton@ufpe.br, E-mail: alberto.silva@barreiros.ifpe.edu.br, E-mail: linomarvic@gmail.com, E-mail: otavio.santos@vitoria.ifpe.edu.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco (IFPE), Barreiros, PE (Brazil); Centro de Aplicaciones Tecnologicas y Dessarrollo Nuclear (CEADEN), La Habana (Cuba)

    2017-11-01

    Northeastern Brazil is a region with a large number of natural radioactive occurrences. Monitoring studies carried out over the last 30 years have identified a hundred anomalous points, especially in the State of Paraiba, more specifically the region of Serido Ocidental Paraibano, geologically characterized by the presence of rocky outcrops with radioactive materials associated with granites and pegmatites. Regions with differentiated levels of natural radioactivity and, consequently, greater radioecological relevance, have been the constant object of radiometric and dosimetric studies. Considering their relevance, the present study aimed to evaluate the levels of natural radioactivity in rocks located in the Riacho da Serra and Serra dos Porcos, previously unmonitored, located in the municipalities of Sao Jose do Sabugi and Santa Luzia, in Paraiba, Northeast of Brazil. The radiometric evaluation was performed by measuring the specific activities of U-238, Th-232 and K-40 in rock samples using a high resolution gamma spectrometry system. The mean specific activities of U-238, Th-232 and K-40 were: 2562.30 ± 672.22; 180.68 ± 672.22 and 1374.13 ± 36.90 Bq/kg, respectively. The monitored radionuclides presented high values of specific activity, being 1.6; 4.1 and 71.2 times higher than the mean values for the earth's crust. (author)

  9. Performance analysis of gamma ray spectrometric parameters on digital signal and analog signal processing based MCA systems using NaI(Tl) detector.

    Science.gov (United States)

    Kukreti, B M; Sharma, G K

    2012-05-01

    Accurate and speedy estimations of ppm range uranium and thorium in the geological and rock samples are most useful towards ongoing uranium investigations and identification of favorable radioactive zones in the exploration field areas. In this study with the existing 5 in. × 4 in. NaI(Tl) detector setup, prevailing background and time constraints, an enhanced geometrical setup has been worked out to improve the minimum detection limits for primordial radioelements K(40), U(238) and Th(232). This geometrical setup has been integrated with the newly introduced, digital signal processing based MCA system for the routine spectrometric analysis of low concentration rock samples. Stability performance, during the long counting hours, for digital signal processing MCA system and its predecessor NIM bin based MCA system has been monitored, using the concept of statistical process control. Monitored results, over a time span of few months, have been quantified in terms of spectrometer's parameters such as Compton striping constants and Channel sensitivities, used for evaluating primordial radio element concentrations (K(40), U(238) and Th(232)) in geological samples. Results indicate stable dMCA performance, with a tendency of higher relative variance, about mean, particularly for Compton stripping constants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Decay heat curve evaluation test

    Science.gov (United States)

    Akiyama, M.; Doda, K.; Ida, T.; Hashidura, H.; Oka, M.; Yasu, N.

    1981-03-01

    Fission-product decay energy release rates were measured for fast neutron fissions of U-235, Pu-239, U-238, Th-232 and natural uranium for gamma-ray, and U-235 and Pu-239 for beta-ray. Gamma-ray energy spectra were measured using a NaI scintillation detector and beta ray energy spectra were obtained using a plastic scintillation detector combined with a transmission type proportional counter to eliminate gamma-ray effects. The measuremens were made covering times following irradiations from 19 to 24,000 seconds. The spectra data were integrated to provide total energy release rates as a function of time after fission. The present data of beta ray energy release rates are preliminary due to current carrying out of the data analyses. Typical uncertainties in the present data are approximately 5 percent (1 sigma) except for Th-232, and approximately 8 percent for Th-232. The present results were compared with the results of summation calculations using the TASAKA, ENDF/B-IV and JNDC decay data files.

  11. Mini Fission-Fusion-Fission Explosions (Mini-Nukes). A Third Way Towards the Controlled Release of Nuclear Energy by Fission and Fusion

    Science.gov (United States)

    Winterberg, F.

    2004-06-01

    Chemically ignited nuclear microexplosions with a fissile core, a DT reflector and U238 (Th232) pusher, offer a promising alternative to magnetic and inertial confinement fusion, not only burning DT, but in addition U238 (or Th232), and not depending on a large expensive laser of electric pulse power supply. The prize to be paid is a gram size amount of fissile material for each microexplosion, but which can be recovered by breeding in U238. In such a "mini-nuke" the chemical high explosive implodes a spherical metallic shell onto a smaller shell, with the smaller shell upon impact becoming the source of intense black body radiation which vaporizes the ablator of a spherical U238 (Th232) pusher, with the pusher accelerated to a velocity of ˜200 km/s, sufficient to ignite the DT gas placed in between the pusher and fissile core, resulting in a fast fusion neutron supported fission reaction in the core and pusher. Estimates indicate that a few kg of high explosives are sufficient to ignite such a "mini-nuke", with a gain of ˜103, releasing an energy equivalent to a few tons of TNT, still manageable for the microexplosion to be confined in a reactor vessel. A further reduction in the critical mass is possible by replacing the high explosive with fast moving solid projectiles. For light gas gun driven projectiles with a velocity of ˜ 10 km/s, the critical mass is estimated to be 0.25 g, and for magnetically accelerated 25 km/s projectiles it is as small as ˜ 0.05 g. With the much larger implosion velocities, reached by laser- or particle beam bombardment of the outer shell, the critical mass can still be much smaller with the fissile core serving as a fast ignitor. Increasing the implosion velocity decreases the overall radius of the fission-fusion assembly in inverse proportion to this velocity, for the 10 km/s light gas gun driven projectiles from 10 cm to 5 cm, for the 25 km/s magnetically projectiles down to 2 cm, and still more for higher implosion velocities.

  12. Effect of precipitation, sorption and stable of isotope on maximum release rates of radionuclides from engineered barrier system (EBS) in deep repository.

    Science.gov (United States)

    Malekifarsani, A; Skachek, M A

    2009-10-01

    shown that the concentrations of the following radionuclides are limited by solubility and precipitate around the waste and buffer: U, Np, Ra, Sm, Zr, Se, Tc, and Pd. The Sensitivity of maximum release rates in case precipitation shows that some nuclides such as Cs-135, Nb-94, Nb-93 m, Zr-93, Sn-126, Th-230, Pu-240, Pu-242, Pu-239, Cm-245, Am-243, Cm-245, U-233, Ac-227, Pb-210, Pa-231 and Th-229 are very little changed in case the maximum release rate from EBS corresponding to eliminate precipitation in buffer material. Some nuclides such as Se-79, Tc-99, Pd-107, Th-232, U-236, U-233, Ra-226, Np-237 U-235, U-234, and U-238 are virtually changed in the maximum release rate compared to case that taking account precipitation. In Sensitivity of maximum release rates in case to taking account stable isotopes (according to the table of inventory) there are only some nuclides with their stable isotopes in the vitrified waste. And calculation shows that Pd-107 and Se-79 are very increase in case eliminate stable isotope. The Sensitivity of maximum release rates in case retardation with sorption shows that some nuclides such as Pu-240, Pu-241, Pu-239, Cm-245, Am-241, Cm-246, and Am-243 are increased in some time in case maximum release rate from EBS corresponding to eliminate retardation in buffer material. Some nuclides such as U-235, U-233 and U-236 have a little decrease in case maximum release because their parents have short live and before decay to their daughter will released from the EBS. If the characteristic time taken for a nuclide to diffuse across the buffer exceeds its half-life, then the release rate of that nuclide from the EBS will be attenuated by radioactive decay. Thus, the retardation of the diffusion process due to sorption tends to reduce the release rates of short-lived nuclides more effectively than for the long-lived ones. For example, release rates of Pu-240, Cm-246 and Am-241, which are relatively short-lived and strongly sorbing, are very small

  13. Investigation of the radioactivity in air, water and soil in the Estado de Chihuahua; Investigacion de la radiactividad en aire, agua y suelo en el Estado de Chihuahua

    Energy Technology Data Exchange (ETDEWEB)

    Montero C, M.E.; Renteria V, M.; Herrera P, E.F.; Villalba, M.L. [Centro de Investigacion en Materiales Avanzados, S. C., Miguel de Cervantes 120, Complejo Industrial Chihuahua, C.P. 31109, Chihuahua (Mexico); Colmenero S, L.H. [CIMAV e Instituto Tecnologico de Chihuahua, Av. de las Industrias 11101, Chihuahua (Mexico)]. e-mail: elena.montero@cimav.edu.mx

    2004-07-01

    The results of the determinations of activities of the series of U-238, Th-232 and the K-40 in soils, of the Rn-222 in the air of the domiciles, and in underground water are presented, as well as the total uranium activity in underground water, product of an extensive sampling in the state of Chihuahua. In two of the aquifers a positive correlation was obtained among the concentration of total uranium and the Rn-222 dissolved in the water of each well. Also it was finds a positive tendency among the averages of the concentration of U-238 in the soil and of the concentration of Rn-222 in the air of the domiciles in different towns, and among the averages of the concentration of U-238 in the floor and of the concentration of the Rn-222 dissolved in the well water in different aquifer. It is suggested that the constitution for rocks more or less uraniferous of the alluvial valleys gives explanation to the observed correlations. (Author)

  14. Assessment of natural and artificial radioactivity levels and radiation hazards and their relation to heavy metals in the industrial area of Port Said city, Egypt.

    Science.gov (United States)

    Attia, T E; Shendi, E H; Shehata, M A

    2015-02-01

    A detailed gamma ray spectrometry survey was carried out to make an action in environmental impact assessment of urbanization and industrialization on Port Said city, Egypt. The concentrations of the measured radioelements U-238, Th-232 in ppm, and K-40 %, in addition to the total counts of three selected randomly dumping sites (A, B, and C) were mapped. The concentration maps represent a base line for the radioactivity in the study area in order to detect any future radioactive contamination. These concentrations are ranging between 0.2 and 21 ppm for U-238 and 0.01 to 13.4 ppm for Th-232 as well as 0.15 to 3.8 % for K-40, whereas the total count values range from 8.7 to 123.6 uR. Moreover, the dose rate was mapped using the same spectrometer and survey parameters in order to assess the radiological effect of these radioelements. The dose rate values range from 0.12 to 1.61 mSv/year. Eighteen soil samples were collected from the sites with high radioelement concentrations and dose rates to determine the activity concentrations of Ra-226, Th-232, and K-40 using HPGe spectrometer. The activity concentrations of Ra-226, Th-232, and K-40 in the measured samples range from 18.03 to 398.66 Bq kg(-1), 5.28 to 75.7 Bq kg(-1), and 3,237.88 to 583.12 Bq kg(-1), respectively. In addition to analyze heavy metal for two high reading samples (a 1 and a 10) which give concentrations of Cd and Zn elements (a 1 40 ppm and a 10 42 ppm) and (a 1 0.90 ppm and a 10 0.97 ppm), respectively, that are in the range of phosphate fertilizer products that suggested a dumped man-made waste in site A. All indicate that the measured values for the soil samples in the two sites of three falls within the world ranges of soil in areas with normal levels of radioactivity, while site A shows a potential radiological risk for human beings, and it is important to carry out dose assessment program with a specifically detailed monitoring program periodically.

  15. Reexamining the heavy-ion reactions 238U+238U and 238U+248Cm and actinide production close to the barrier

    Science.gov (United States)

    Kratz, J. V.; Schädel, M.; Gäggeler, H. W.

    2013-11-01

    Recent theoretical work has renewed interest in radiochemically determined isotope distributions in reactions of 238U projectiles with heavy targets that had previously been published only in parts. These data are being reexamined. The cross sections σ(Z) below the uranium target have been determined as a function of incident energy in thick-target bombardments. These are compared to predictions by a diffusion model whereby consistency with the experimental data is found in the energy intervals 7.65-8.30 MeV/u and 6.06-7.50 MeV/u. In the energy interval 6.06-6.49 MeV/u, the experimental data are lower by a factor of 5 compared to the diffusion model prediction indicating a threshold behavior for massive charge and mass transfer close to the barrier. For the intermediate energy interval, the missing mass between the primary fragment masses deduced from the generalized Qgg systematics including neutron pair-breaking corrections and the centroid of the experimental isotope distributions as a function of Z have been used to determine the average excitation energy as a function of Z. From this, the Z dependence of the average total kinetic-energy loss (TKEL¯) has been determined. This is compared to that measured in a thin-target counter experiment at 7.42 MeV/u. For small charge transfers, the values of TKEL¯ of this work are typically about 30 MeV lower than in the thin-target experiment. This difference is decreasing with increasing charge transfer developing into even slightly larger values in the thick-target experiment for the largest charge transfers. This is the expected behavior which is also found in a comparison of the partial cross sections for quasielastic and deep-inelastic reactions in both experiments. The cross sections for surviving heavy actinides, e.g., 98Cf, 99Es, and 100Fm indicate that these are produced in the low-energy tails of the dissipated energy distributions, however, with a low-energy cutoff at about 35 MeV. Excitation functions show that identical isotope distributions are populated independent of the bombarding energy indicating that the same bins of excitation energy are responsible for the production of these fissile isotopes. A comparison of the survival probabilities of the residues of equal charge and neutron transfers in the reactions of 238U projectiles with either 238U or 248Cm targets is consistent with such a cutoff as evaporation calculations assign the surviving heavy actinides to the 3n and/or 4n evaporation channels.

  16. Reliability of using 238U/235U and 234U/238U ratios from alpha spectrometry as qualitative indicators of enriched uranium contamination.

    Science.gov (United States)

    Minteer, Mark; Winkler, Paul; Wyatt, Bill; Moreland, Scott; Johnson, Jamie; Winters, Tim

    2007-05-01

    Alpha spectrometry is a commonly used technique for the measurement of uranium isotopes in environmental samples because it is widely available at a relatively low cost. For natural uranium the (234)U to (238)U activity ratio should be 1 and the (238)U to (235)U activity ratio should be 21.7. However, a lower (238)U to (235)U ratio is usually observed in alpha spectrometric analysis of environmental soil samples. This observation has led to the conclusion that soils from nuclear weapons facilities were contaminated with highly enriched uranium. This study was undertaken to test the reliability of using activity ratios from alpha spectrometry to infer the presence of highly enriched uranium in soil samples. The results of these experiments indicate that the (238)U to (235)U activity ratio is not a reliable indicator, but that the (234)U to (238)U activity ratio can be used to qualitatively indicate the presence of highly enriched uranium at concentrations near 10 ng g(-1) and above.

  17. Characterization of phosphogypsum wastes associated with phosphoric acid and fertilizers production.

    Science.gov (United States)

    El Afifi, E M; Hilal, M A; Attallah, M F; El-Reefy, S A

    2009-05-01

    The present work is directed to characterize the phosphogypsum (PG) wastes associated with phosphoric acid produced by the wet process in industrial facility for the production of fertilizers and chemicals in Egypt. The PG waste samples were characterized in terms of spectroscopic analysis (X-ray diffraction, X-ray fluorescence, IR spectra) and radiometric analysis (gamma- and alpha-measurements). The gamma-ray measurements showed that the average activity concentrations are 140+/-12.6, 459+/-36.7, 323+/-28.4, 8.3+/-0.76 and 64.3+/-4.1 Bq/kg for U-238, Ra-226, Pb-210, Th-232 and K-40, respectively. The alpha-particle measurements of uranium isotopes showed that the average activity concentrations of U-238, U-235 and U-234 were 153+/-9.8, 7+/-0.38, 152+/-10.4 Bq/kg, respectively. The average radiochemical recovery (%) of the destructive alpha-particle measurements is approximately 70% with a resolution (FWHM) of approximately 30 keV. Activity ratios of U-238/Ra-226 and U-238/Pb-210 were less than unity (i.e., 370 Bq/kg), total absorbed gamma dose rate (D(gamma r)>5 nGy/h) and radon emanation fraction (Rn-EF>20%). Uncertainty of the sample counting was 95% confidence level of sigma. The results indicated the necessity to find suitable routes to decrease and/or redistribute the radionuclide of environmental interest (i.e., Ra-226) in PG wastes, consequently to reduce its radiation impacts in the surrounding environment.

  18. Special Analysis for the Disposal of the Idaho National Laboratory Unirradiated Light Water Breeder Reactor Rods and Pellets Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-08-31

    The purpose of this special analysis (SA) is to determine if the Idaho National Laboratory (INL) Unirradiated Light Water Breeder Reactor (LWBR) Rods and Pellets waste stream (INEL103597TR2, Revision 2) is suitable for disposal by shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS). The INL Unirradiated LWBR Rods and Pellets waste stream consists of 24 containers with unirradiated fabricated rods and pellets composed of uranium oxide (UO2) and thorium oxide (ThO2) fuel in zirconium cladding. The INL Unirradiated LWBR Rods and Pellets waste stream requires an SA because the 229Th, 230Th, 232U, 233U, and 234U activity concentrations exceed the Nevada National Security Site (NNSS) Waste Acceptance Criteria (WAC) Action Levels.

  19. Occupational exposure to natural radioactivity in a zircon sand milling plant

    Energy Technology Data Exchange (ETDEWEB)

    Ballesteros, Luisa [Laboratorio de Radioactividad Ambiental, Universidad Politecnica de Valencia, Apartado 22012, E-46071 Valencia (Spain)], E-mail: lballest@upvnet.upv.es; Zarza, Isidoro [Laboratorio de Radioactividad Ambiental, Universidad Politecnica de Valencia, Apartado 22012, E-46071 Valencia (Spain)], E-mail: iszarpe@upvnet.upv.es; Ortiz, Josefina [Laboratorio de Radioactividad Ambiental, Universidad Politecnica de Valencia, Apartado 22012, E-46071 Valencia (Spain)], E-mail: jortiz@iqn.upv.es; Serradell, Vicente [Laboratorio de Radioactividad Ambiental, Universidad Politecnica de Valencia, Apartado 22012, E-46071 Valencia (Spain)], E-mail: vserradell@iqn.upv.es

    2008-10-15

    Raw zirconium sand is one of the substances (naturally occurring radioactive material, NORM) which is widely used in the ceramic industry. This sand contains varying concentrations of natural radionuclides: mostly U-238 but also Th-232 and U-235, together with their daughters, and therefore may need to be regulated by Directive 96/29/EURATOM. This paper describes the method used to perform the radiological study on a zircon sand milling plant and presents the results obtained. Internal and external doses were evaluated using radioactivity readings from sand, airborne dust, intermediate materials and end products. The results on total effective dose show the need for this type of industry to be carefully controlled, since values near to 1 mSv were obtained.

  20. True coincidence summing corrections for an extended energy range HPGe detector

    Energy Technology Data Exchange (ETDEWEB)

    Venegas-Argumedo, Y. [Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de Cervantes 120, Chihuahua, Chih 31109 (Mexico); M.S. Student at CIMAV (Mexico); Montero-Cabrera, M. E., E-mail: elena.montero@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de Cervantes 120, Chihuahua, Chih 31109 (Mexico)

    2015-07-23

    True coincidence summing (TCS) effect for natural radioactive families of U-238 and Th-232 represents a problem when an environmental sample with a close source-detector geometry measurement is performed. By using a certified multi-nuclide standard source to calibrate an energy extended range (XtRa) HPGe detector, it is possible to obtain an intensity spectrum slightly affected by the TCS effect with energies from 46 to 1836 keV. In this work, the equations and some other considerations required to calculate the TCS correction factor for isotopes of natural radioactive chains are described. It is projected a validation of the calibration, performed with the IAEA-CU-2006-03 samples (soil and water)

  1. Calculation of the radiation doses occurring in the human body for inadvertent ingestion of soil and other soil exposure pathways

    Science.gov (United States)

    Oner, F.; Okumuolu, N.

    2003-11-01

    We estimate the radiation doses in the human body, in the Gudalore region in India, following the inadvertent ingestion of soil and exposure to other soil pathways by measuring Th-232, U-238, and K-40. We estimate the equivalent dose in eleven different organs and the absorbed dose calculations for the whole body. The annual effective doses are calculated, the lowest is in Kariyasolai at 7.8 x 10(-3) mSv whereas the highest is in Ponnur at 8.9 x 10(-2) mSv. In all regions, the lowest equivalent doses through inadvertent soil ingestion are calculated in the kidney and thyroid whereas the highest doses are in the red marrow and on the bone surface.

  2. The role of nano-perovskite in the negligible thorium release in seawater from Greek bauxite residue (red mud)

    DEFF Research Database (Denmark)

    Gkamaletsos, Platon; Godelitsas, Athanasios; Kasama, Takeshi

    2016-01-01

    . The bulk chemical analyses showed considerable levels of Th (111 mu g g(-1)), along with minor U (15 mu g g(-1)), which are responsible for radioactivity (355 and 133 Bq kg(-1) for Th-232 and U-238, respectively) with a total dose rate of 295 nGy h(-1). Leaching experiments, in conjunction with SF...... incorporation into an insoluble perovskite-type phase with major composition of Ca0.8Na0.2TiO3 and crystallites observed in nanoscale. The Th L-III-edge EXAFS spectra demonstrated that Th4+ ions, which are hosted in this novel nano-perovskite of BR, occupy Ca2+ sites, rather than Ti4+ sites. That is most likely...

  3. Scintillation gamma spectrometer for analysis of hydraulic fracturing waste products.

    Science.gov (United States)

    Ying, Leong; O'Connor, Frank; Stolz, John F

    2015-01-01

    Flowback and produced wastewaters from unconventional hydraulic fracturing during oil and gas explorations typically brings to the surface Naturally Occurring Radioactive Materials (NORM), predominantly radioisotopes from the U238 and Th232 decay chains. Traditionally, radiological sampling are performed by sending collected small samples for laboratory tests either by radiochemical analysis or measurements by a high-resolution High-Purity Germanium (HPGe) gamma spectrometer. One of the main isotopes of concern is Ra226 which requires an extended 21-days quantification period to allow for full secular equilibrium to be established for the alpha counting of its progeny daughter Rn222. Field trials of a sodium iodide (NaI) scintillation detector offers a more economic solution for rapid screenings of radiological samples. To achieve the quantification accuracy, this gamma spectrometer must be efficiency calibrated with known standard sources prior to field deployments to analyze the radioactivity concentrations in hydraulic fracturing waste products.

  4. Simultaneous determination of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry INa(Ti), in solid samples.; Determinacion de U (Natural), Th (Natural) y Ra-226 en diversos materiales, mediante espectrometria con INa (TI)

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, S.; Navarro, T.; Alvarez, A.

    1991-07-01

    A method has been developed to determine activities of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry. The measurement system has been calibrated using standards specially prepared at the laboratory. It is necessary to assume secular equilibrium in the samples, between Ra-226 and Th-232 and its daughters nuclides, and between U-238 and its immediate daughter Th-234, as the photo peaks measured are those of the daughters. The results obtained indicate that this method can of ter replace the radiochemical techniques used to measure activities in this type of sample. The method has been successfully used to determine these natural isotopes in samples from uranium mills. (Author) 9 refs.

  5. Natural radioactivity in stream sediments of Oltet River, Romania

    Science.gov (United States)

    Ion, Adriana

    2017-04-01

    The concentration of naturally occurring radionuclides (U-238, Th-232 and K-40) in stream sediments of the Oltet River was measured in order to establish the primary sources of radionuclides, the transport pathways and the geochemical factors favouring their mobilisation and concentration in the existing geological context. The Oltet River has a length of 185 Km and crosses the southern central part of the country, being the right tributary of the Olt River. The range in elevation of the watercourse varies between 1963 m in the springs area (Parîng Mountains) and 200 m at the confluence with the Olt River, whereas the relief of the Oltet Basin has a varied character, manifested by the presence of diverse forms of relief, starting with major mountainous heights and ending with low-lying plains regions. In cross section from North to South, the Olteț River cuts metamorphic rocks (schist, gneisses, quartzite, marble, mica-schist's), magmatic rocks (granite and granitoid massifs - intruded by veins of microgranite, aplite, pegmatite and lamprophyre) and limestone, followed by deposits composed of clays, marls, sands and gravels, that are characterized by the presence of lignite seams. 44 stream sediment samples were collected in summer of 2016 from sampling points distributed along the river with an equidistance of about 4 - 5 km. The activity concentrations of the U-238, Th-232 and K-40 were measured by gamma ray spectrometry using HPGe detector (ORTEC) with 26% relative efficiency in multilayer shielding. The reference materials used were IAEA - RGK-1 and IAEA - 314. Analysis was performed on the geochemical process the amounts of thorium and potassium released are modest, leaching of uranium being the dominant feature (uranyl ion). The downstream lignite seams are the secondary geochemical barriers in accumulation of uranium; the radiometric data obtained for stream sediments emphasize this enrichment.

  6. Minimization of the fission product waste by using thorium based fuel instead of uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Galahom, A. Abdelghafar, E-mail: Agalahom@yahoo.com

    2017-04-01

    This research discusses the neutronic characteristics of VVER-1200 assembly fueled with five different fuel types based on thorium. These types of fuel based on mixing thorium as a fertile material with different fissile materials. The neutronic characteristics of these fuels are investigated by comparing their neutronic characteristics with the conventional uranium dioxide fuel using the MCNPX code. The objective of this study is to reduce the production of long-lived actinides, get rid of plutonium component and to improve the fuel cycle economy while maintaining acceptable values of the neutronic safety parameters such as moderator temperature coefficient, Doppler coefficient and effective delayed neutrons (β). The thorium based fuel has a more negative Doppler coefficient than uranium dioxide fuel. The moderator temperature coefficient (MTC) has been calculated for the different proposed fuels. Also, the fissile inventory ratio has been calculated at different burnup step. The use of Th-232 as a fertile material instead of U-238 in a nuclear fuel is the most promising fuel in VVER-1200 as it is the ideal solution to avoid the production of more plutonium components and long-lived minor actinides. The reactor grade plutonium accumulated in light water reactor with burnup can be recycled by mixing it with Th-232 to fuel the VVER-1200 assembly. The concentrations of Xe-135 and Sm-151 have been investigated, due to their high thermal neutron absorption cross section.

  7. Determination of specific activities of U-238, Ra-226, Ra-228 e Th-228 in samples of mineral fertilizers with phosphorus; Determinacao das atividades especificas de U-238, Ra-226, Ra-228 e Th-228 em amostras de fertilizantes minerais com fosforo

    Energy Technology Data Exchange (ETDEWEB)

    Garcez, R.W.D.; Lopes, J.M.; Silva, A.X. da, E-mail: rgarcez@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharoa (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Domingues, A.M.; Lima, M.A.F. [Universidade Federal Fluminense (UFF),Niteroi, RJ (Brazil)

    2016-07-01

    Samples were analyzed by gamma spectrometry mineral fertilizers with the HPGe detector and aid LabSOCS software for calculating the detection efficiency curve. Specific activities found for Pa-234m, Ra-226, Ra-228 and Th-228 in samples of phosphate fertilizers were 505 Bq.kg{sup -1}, 458 Bq.kg{sup -1}, 450 Bq.kg{sup -1} and 394 Bq.kg{sup -1}, respectively. And for the NPK fertilizer samples were found average values of 390 Bq.kg{sup -1}, 252 Bq.kg{sup -1}, 280 Bq.kg{sup -1} and 268 Bq.kg{sup -1}, respectively. (author)

  8. Absorbed dose rate due to intake of natural radionuclides by Tilapia fish (Tilapia nilotica, Linnaeus, 1758) estimated near uranium anomaly at Santa Quiteria, Ceara, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Wagner de [Industrias Nucleares do Brasil S.A. (INB), Pocos de Caldas, MG (Brazil). Coordenacao de Protecao Radiologica. Unidade de Tratamento de Minerios], E-mail: wspereira@inb.gov.br; Kelecom, Alphonse [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-graduacao em Ciencia Ambiental; Py Junior, Delcy de Azevedo [Industrias Nucleares do Brasil S.A. (INB), Caetite, BA (Brazil). Coordenacao de Protecao Radiologica. Unidade de Concentrado de Uranio], E-mail: Delcy@inb.gov.br

    2007-07-01

    The uranium mining at Santa Quiteria (Santa Quiteria Unit - USQ) is in its environmental licensing phase. Aiming to estimate the radiological environmental impact of the USQ, a monitoring program is underway. However, radioprotection of biota is not explicitly mentioned in Brazilian norms. In order to preserve the biota of the deleterious effects from radiation and to behave in a pro-active way as expected by licensing organs, the present work aims to use an environmental protection methodology, based on the calculation of absorbed dose rate in biota. Thus, selected biomarker was the fish tilapia (Tilapia nilotica, Linnaeus, 1758) and the radionuclides were: uranium (U-238), thorium (Th-232), radium (Ra-226 and Ra-228) and lead (Pb-210). Since there are no exposition limits for biota, in Brazil, the value proposed by the Department of Energy (DOE) of the United States of 3.5 x 10{sup 3} {mu}Gy/y has been used. The derived absorbed dose rate calculated for tilapia was 2.76 x 10{sup 0} {mu}Gy/y, that is less than 0.1 % of the limit established by DOE. The critical radionuclide was U-238, with 99% of the absorbed dose rate. This value of 0.1% of the limit allows to state that in pre-operational conditions analyzed natural radionuclides do not represent a radiological problem to the biota. (author)

  9. Development of the NIST bone ash standard reference material for environmental radioactivity measurement.

    Science.gov (United States)

    Lin, Z; Inn, K G; Altzitzoglou, T; Arnold, D; Cavadore, D; Ham, G J; Korun, M; Wershofen, H; Takata, Y; Young, A

    1998-01-01

    The bone ash standard reference material (SRM), a blend of 4% contaminated human bone and 96% diluent bovine bone, has been developed for radiochemical method validation and quality control for radio-bone analysis. The massic activities of 90Sr, 226Ra, 230Th, 232Th, 234U, 235U, 238U, 238Pu, (239 + 240)Pu and (243 + 244)Cm were certified using a variety of radiochemical procedures and detection methods. Measurements confirmed undetectable radionuclide heterogeneity down to a sample size of 5 g. thereby implying adequate blending of particulate materials with dilution factors of up to 17,900. The results among most of the intercomparison laboratories and their methods were consistent. Disequilibrium was observed for decay chains: 234U(0.67 mBq/g)-230Th(0.47 mBq/g)-226Ra(15.1 mBq/g)-210Pb(23 mBq/g)-210Po(13 mBq/g) and 232Th(0.99 mBq/g)-228 Ra(6.1 mBq/g)-228Th(7.1 mBq/g). The disequilibria were the results of mixing occupationally contaminated human bone with natural bovine bone and the fractionation during internal biological processes. The massic activity of 210Pb, 228Th and 241Am were not certified because of insufficient 228Ra and 241Pu data and lack of knowledge in how 222Rn and its daughters will be fractionated in the SRM bottle over time.

  10. Study of the radiological impact of the construction materials in Argentina; Estudio del impacto radiologico de los materiales de la construccion en Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Quintana, E.; Serdeiro, G.; Fernandez, J.; Ciallella, H. [ARN, Av. Del Liberatdor 8250, Buenos Aires (1429) (Argentina)]. e-mail: equintan@cae.arn.gov.ar

    2006-07-01

    Some countries have established specific regulations on the radioactivity content of the construction materials (MC), while others are considering if its are necessary specific regulations. The purpose of limiting these radioactivity levels, it is to restrict the exposure to the radiation due to the natural or increased content of the natural radionuclides. All the used materials for the construction possess variable quantities of natural radionuclides. The materials derived of the rocks and soils contain mainly the radionuclides of the natural chains of the U-238 and of the Th-232 and the K-40 radionuclide. The Nuclear Regulatory Authority is carrying out studies of the concentration of Ra-226, Th-232 and K-40 in different MC with the final purpose of providing recommendations that apply its to control the levels of radioactivity of the same ones. However, it should be kept in mind that restrictions on the use of certain MC could have important economic, environmental or social consequences so much in the regional as national confines. Such consequences should be evaluated and considered together with the radioactivity levels when establishing recommendations or regulations. The exposure to the radiation coming from the MC can be divided in external and internal. The external exposure is caused by direct gamma irradiation, coming from the radioactive decay of the natural radionuclides. The internal irradiation is caused by the inhalation of Rn-222 (radon), Rn-220 (thoron) and its offspring. The radon is part of the decay series of the uranium that is present in the MC. The biggest source of radon production is undoubtedly the soil, but in some cases the MC can to produce an outstanding contribution. These can also be an important source of thoron production when they contain high concentrations of Thorium. In this work the results of the measurements of Ra-226, Th-232 and K-40 carried out in leader trademarks of cements and plasters of national origin that are

  11. Correlation of radioactive waste treatment costs and the environmental impact of waste effluents in the nuclear fuel cycle: reprocessing of high-temperature gas-cooled reactor fuel containing U-233 and thorium

    Energy Technology Data Exchange (ETDEWEB)

    Davis, W. Jr.; Blanco, R.E.; Finney, B.C.; Hill, G.S.; Moore, R.E.; Witherspoon, J.P.

    1976-05-01

    A cost/benefit study was made to determine the cost and effectiveness of various radioactive waste (radwaste) treatment systems for decreasing the release of radioactive materials from a model high-temperature gas-cooled reactor (HTGR) fuel reprocessing plant and to determine the radiological impact (dose commitment) of the released materials on the environment. The study is designed to assist the U. S. Nuclear Regulatory Commission in defining the term as low as reasonably achievable as it applies to this nuclear facility. The base case is representative of conceptual, developing technology of head-end graphite-burning operations and of extensions of solvent-extraction technology of current designs for light-water-reactor (LWR) fuel reprocessing plants. The model plant has an annual capacity of 450 metric tons of heavy metal (MTHM, where heavy metal is uranium plus thorium), as charged to about fifty 1000-MW(e) HTGRs. Additional radwaste treatment systems are added to the base-case plant in a series of case studies to decrease the amounts of radioactive materials released and to reduce the radiological dose commitment to the population in the surrounding area. The capital and annual costs for the added waste treatment operations and the corresponding reductions in dose commitments are calculated for each case. In the final analysis, the cost/benefit of each case, calculated as additional cost of radwaste system divided by the reduction in dose commitment, is tabulated or the dose commitment is plotted with cost as the variable. The status of each of the radwaste treatment methods used in the case studies is discussed.

  12. REAKTOR INNOVATIVE MOLTEN SALT (IMSR DENGAN SISTEM KESELAMATAN PASIF MENYELURUH

    Directory of Open Access Journals (Sweden)

    Andang Widiharto

    2015-04-01

    Full Text Available Pengembangan Teknologi Reaktor Nuklir pada masa mendatang mengarah pada peningkatan aspek keselamatan, peningkatan pendayagunaan bahan bakar, reduksi limbah radioaktif, ketahanan terhadap proliferasi bahan-bakar nuklir dan peningkatan aspek ekonomi. reaktor Innovative Molten Salt (IMSR adalah reaktor nuklir yang menggunakan bahan bakar cair berupa garam lebur fluoride (7LiF-ThF4-UF4-MaFx. Reaktor IMSR didesain sebagai reaktor pembiak termal, yaitu membiakkan U-233 dari Th-232. Hal ini untuk menjawab permasalahan sustainabilitas ketersedian sumber daya bahan bakar nuklir dan reduksi limbah radioaktif. Dalam aspek keselamatan, desain reaktor IMSR memiliki sifat inherent safe, yaitu koefisien umpan balik daya yang negatif serta memiliki fitur-fitur keselamatan pasif. Fitur-fitur keselamatan pasif terdiri dari sistem shutdown pasif, sistem pendinginan pasif pasca shutdown serta sistem pendinginan pasif untuk produk fisi. Kecelakaan yang berpotensi terjadi pada IMSR, yaitu kecelakaan kehilangan aliran bahan bakar, kecelakaan kehilangan aliran pendingin, kecelakaan kehilangan kemampuan pengambilan kalor serta kecelakaan kerusakan integritas sistem reaktor, dapat ditangani sepenuhnya secara pasif hingga mencapai kondisi shutdown selamat. Kata kunci: keselamatan pasif, inherent safe, IMSR   The next Nuclear Reactor Technology developments are directed to the increasing of the aspects of safety, fuel utility, radioactive waste reduction, proliferation retention and economy. Innovative Molten Salt Reactor (IMSR is a nuclear reactor design that uses fluoride molten salt (7LiF-ThF4-UF4-MaFx. IMSR is designed as a thermal breeder reactor, i.e. to produce U-233 from Th-232. This is the answer of natural nuclear fuel sustainability and radioactive waste problems. In term of safety aspect, IMSR design has inherent safe characteristics, i.e. negative power feedback coefficient, and passive safety features. The passive safety features are passive shutdown

  13. Natural radioactivity of some spring and bottled mineral waters from several central Balkan sites, as a way of their characterization

    Directory of Open Access Journals (Sweden)

    SCEPAN S. MILJANIC

    2007-06-01

    Full Text Available In this work, a study of the radioactive content of some spring and bottled mineral waters originating frommetamorphic rock areas was carried out.Ahigh content of radium isotopes (226Ra, 228Ra, was found by radiometric analysis in the spring waters: Studenica (226Ra: 289 mBq/L, ^ibutkovica (226Ra: 92, 4 mBq/L, 228Ra: 610 mBq/L, and Crni Guber (226Ra: 120 mBq/L, 228Ra: 1170 mBq/L. On the other hand, the radiochemical results showed a higher concentration of 238U in the bottled mineral water samples (dissolved uranium concentrations were from 0.21 mBq/L, for "Kopaonik" to 71.5mBq/L fo "Skadarska" than in the spring water samples (dissolved uranium concentrations were very low » 10 mBq/L. The concentrations of all the present naturally occuring radionuclides: 238U, 234U, 232Th, 230Th, 228Th, 228Ra and 226Ra were determined by alpha/gamma spectrometric analysis. The activity ratios 234U/238U, 226Ra/230Th and 228Th/232Th, 228Ra/228Th were calculated and are discussed as an indication of the radioactive disequilibrium in bothe the 238U and 232Th radioactive series. The high contents of radium isotopes with respect to the equilibrium values expected from the respective parents 232Th/(232Th series and 230Th (238U series found in the spring water samples is the main evidence for the existence of significant radioactive disequilibrium in both the radioactive series.

  14. Ionizing radiation dose due to the use of agricultural fertilizers;Dose de radiacao ionizante decorrente do uso de fertilizantes agricolas

    Energy Technology Data Exchange (ETDEWEB)

    Umisedo, Nancy Kuniko

    2007-07-01

    Among several agents that exist in the environment which can expose to different risks and effects, there is the ionizing radiation whose knowledge of dose is of importance to the effective control and prevention of possible damages to human beings and to the environment. The transfer of radionuclides from fertilizers to/and soils to the foodstuffs can result as an increment in the internal dose when they are consumed by the human beings. This work evaluates the contribution of fertilizers to the ionizing radiation dose in the environment and in the human being. Samples of fertilizers, soils and vegetables produced in fertilized soils were analysed through gamma spectrometry with the use of a hyper pure germanium detector. Measurements of ambient dose with thermoluminescent dosimeters were also performed. In the fertilized soil samples values of specific activities from 36 to 342 Bq/kg for K-40, from 42 to 142 Bq/kg for U-238 and from 36 to 107 Bq/kg for Th-232 were obtained. In the vegetables the values varied from 21 to 118 Bq/kg for K-40 and for the elements of uranium and thorium series the values were less than 2 Bq/kg. In fertilizers the maximum value of 5800 Bq/kg was obtained for K-40, 430 Bq/kg for U-238 and 230 Bq/kg for Th-232. The average values of soil to plant transfer factor were not significantly different among the types of vegetables. The annual committed effective dose of 0.882 muSv due to the ingestion of K-40 from the analysed vegetables is very small if compared to the reference value of 170 muv given by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000). The thermoluminescent dosimetry provided the annual ambient dose equivalent from 1.5 to 1.8 mSv without differences between cultivated and non cultivated fields. Through the results obtained, it was not observed a significant transfer of radionuclides from fertilizers to soils and to foodstuffs in the conditions adopted in this work and consequently there

  15. Transport and exchange of U-series nuclides between suspended material, dissolved load and colloids in rivers draining basaltic terrains

    Science.gov (United States)

    Pogge von Strandmann, Philip A. E.; Burton, Kevin W.; Porcelli, Don; James, Rachael H.; van Calsteren, Peter; Gislason, Sigurður R.

    2011-01-01

    This study presents uranium and thorium concentrations and activity ratios for all riverine phases (bedload, suspended load, dissolved load and colloids) from basaltic terrains in Iceland and the Azores. Small basaltic islands, such as these, are thought to account for ~ 25% of CO2 consumed by global silicate weathering, and for ~ 45% of the flux of suspended material to the oceans. These data indicate that [U] and [Th] in the dissolved and colloidal fractions are strongly controlled by pH, and to a much lesser extent by levels of dissolved organic carbon (which are low in these environments). At high pH, basalt glass dissolution is enhanced, and secondary mineral formation (e.g. Fe-oxyhydroxides and allophane) is suppressed, resulting in high dissolved [U], and low colloidal [U] and [Th], indicating a direct chemical weathering control on elemental abundances. When the dissolved (234U/238U) activity ratio is >~1.3 (i.e. when physical weathering, groundwater contribution or soil formation are high), there is little isotope exchange between dissolved and colloidal fractions. At lower activity ratios, the dissolved load and colloids have indistinguishable activity ratios, suggesting that when chemical weathering rates are high, secondary clay formation is also high, and colloids rapidly adsorb dissolved U. Many of the suspended sediment samples have (234U/238U) activity ratios of > 1, which suggests that uptake of U onto the suspended load is important. Identical (230Th/232Th) in suspended, dissolved and colloidal samples suggests that Th, like U, is exchanged or sorbed rapidly between all riverine phases. This particle-reactivity, combined with poorly constrained contributions from groundwater and hydrothermal water, and short-term variations in input to soils (volcanic and glacial), suggests that U-series nuclides in riverine material from such basaltic terrains are unlikely to reflect steady state erosion processes.

  16. Current status of JENDL-3.3

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Akira [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Current status of JENDL-3.3 is presented. Reevaluation work toward JENDL-3.3 has started last April for three years project to supply a consolidated new versions of JENDL by JAERI NDC (Nuclear Data center) with the cooperation of JNDC (Japanese Nuclear Data Committee). The working schedule has been fixed by the careful review of the summary report, `The problems of JENDL-3.2`, submitted to JNDC last March after one year discussions by a small advisory group: `Identifying the problems of JENDL-3.2`. To cope with the problems, two new subgroups are set up in the Subcommittee of Nuclear Data of JNDC. One is Heavy Mass Elements Evaluation Working Group for the re-evaluation of major actinides (Th-232, U-233,235,236,238, Pu-236,239,241,242). The other is Intermediate Mass Elements Evaluation Working Group for solving the inconsistencies between calculations and integral experiments relating to the fields of fusion neutronics and shielding applications as well as new evaluations such as Er elements. Supplying covariance data for important nuclides are one of the main feature of JENDL-3.3. Re-evaluated data will be released as JENDL-3.3 in the individual bases after the reviewing process by the experts. (author)

  17. LWR First Recycle of TRU with Thorium Oxide for Transmutation and Cross Sections

    Energy Technology Data Exchange (ETDEWEB)

    Andrea Alfonsi; Gilles Youinou

    2012-07-01

    Thorium has been considered as an option to uranium-based fuel, based on considerations of resource utilization (thorium is approximately three times more plentiful than uranium) and as a result of concerns about proliferation and waste management (e.g. reduced production of plutonium, etc.). Since the average composition of natural Thorium is dominated (100%) by the fertile isotope Th-232, Thorium is only useful as a resource for breeding new fissile materials, in this case U-233. Consequently a certain amount of fissile material must be present at the start-up of the reactor in order to guarantee its operation. The thorium fuel can be used in both once-through and recycle options, and in both fast and thermal spectrum systems. The present study has been aimed by the necessity of investigating the option of using reprocessed plutonium/TRU, from a once-through reference LEU scenario (50 GWd/ tIHM), mixed with natural thorium and the need of collect data (mass fractions, cross-sections etc.) for this particular fuel cycle scenario. As previously pointed out, the fissile plutonium is needed to guarantee the operation of the reactor. Four different scenarios have been considered: • Thorium – recycled Plutonium; • Thorium – recycled Plutonium/Neptunium; • Thorium – recycled Plutonium/Neptunium/Americium; • Thorium – recycled Transuranic. The calculations have been performed with SCALE6.1-TRITON.

  18. LWR First Recycle of TRU with Thorium Oxide for Transmutation and Cross Sections

    Energy Technology Data Exchange (ETDEWEB)

    Andrea Alfonsi; Gilles Youinou; Sonat Sen

    2013-02-01

    Thorium has been considered as an option to uranium-based fuel, based on considerations of resource utilization (thorium is approximately three times more plentiful than uranium) and as a result of concerns about proliferation and waste management (e.g. reduced production of plutonium, etc.). Since the average composition of natural Thorium is dominated (100%) by the fertile isotope Th-232, Thorium is only useful as a resource for breeding new fissile materials, in this case U-233. Consequently a certain amount of fissile material must be present at the start-up of the reactor in order to guarantee its operation. The thorium fuel can be used in both once-through and recycle options, and in both fast and thermal spectrum systems. The present study has been aimed by the necessity of investigating the option of using reprocessed plutonium/TRU, from a once-through reference LEU scenario (50 GWd/ tIHM), mixed with natural thorium and the need of collect data (mass fractions, cross-sections etc.) for this particular fuel cycle scenario. As previously pointed out, the fissile plutonium is needed to guarantee the operation of the reactor. Four different scenarios have been considered: • Thorium – recycled Plutonium; • Thorium – recycled Plutonium/Neptunium; • Thorium – recycled Plutonium/Neptunium/Americium; • Thorium – recycled Transuranic. The calculations have been performed with SCALE6.1-TRITON.

  19. Shippingport LWBR (Th/U Oxide) Fuel Characteristics for Disposal Criticality Analysis

    Energy Technology Data Exchange (ETDEWEB)

    L. L. Taylor; H. H. Loo

    1999-09-01

    Department of Energy (DOE)-owned spent nuclear fuels encompass many fuel types. In an effort to facilitate criticality analysis for these various fuel types, they were categorized into eight characteristic fuel groups with emphasis on fuel matrix composition. Out of each fuel group, a representative fuel type was chosen for analysis as a bounding case within that fuel group. Generally, burnup data, fissile enrichments, and total fuel and fissile mass govern the selection of the representative or candidate fuel within that group. The Shippingport Light Water Breeder Reactor (LWBR) fuels incorporate more of the conventional materials (zirconium cladding/heavy metal oxides) and fabrication details (rods and spacers) that make them comparable to a typical commercial fuel assembly. The LWBR seed/blanket configuration tested a light-water breeder concept with Th-232/U-233 binary fuel matrix. Reactor design used several assembly configurations at different locations within the same core . The seed assemblies contain the greatest fissile mass per (displaced) unit volume, but the blanket assemblies actually contain more fissile mass in a larger volume; the atom-densities are comparable.

  20. Fusion-fission-fusion fast ignition plasma focus [rapid communication

    Science.gov (United States)

    Winterberg, F.

    2005-03-01

    A crucial advancement in the problem for the controlled release of energy by nuclear fusion appears possible by an autocatalytic fusion-fission-fusion microexplosion, where the deuterium-tritium (DT) fusion reaction of a dense magnetized DT plasma placed inside a thin liner made up of U238, Th232 (perhaps B10) releases a sufficient number of 14 MeV fusion neutrons which by fission reactions in the liner implode the liner on the DT plasma. The liner implosion increases the DT plasma density and with it the neutron output accelerating the fast fission reactions. Following the fast fission assisted ignition, a thermonuclear detonation wave can propagate into unburnt DT to reach a high gain. The simplest way for the realization of this concept appears to be the dense plasma focus configuration, amended with a nested high voltage magnetically insulated transmission line for the heating of the DT. The large magnetic field needed for the α-particle entrapment of the DT fusion reaction is here generated by the thermomagnetic Nernst effect, amplifying the magnetic field of the plasma focus current sheet.

  1. Autocatalytic Fusion-Fission Burn in the Focus of Two Magnetically Insulated Transmission Lines

    Science.gov (United States)

    Winterberg, F.

    2003-11-01

    A configuration made up of two nested magnetically insulated transmission lines, the inner one carrying a high voltage lower current - and the outer one a high current lower voltage - pulse, was in a previous communication proposed for the ignition of a magnetic field assisted thermonuclear detonation wave. Unlike the fast ignition concept, it does not require the compression of the DT fusion fuel to densities in excess of the solid state. Here I show that with the same configuration, but by surrounding the DT fusion fuel with a blanket of solid U238, Th232 or B10, the ignition of a thermonuclear detonation wave is possible with densities of the DT fuel less than solid state densities, because the DT fusion neutrons can make a sufficient number of fission reactions, greatly increasing the pressure in the blanket, compressing the DT to high densities, launching a magnetic field assisted thermonuclear detonation wave. This autocatalytic fusion-fission burn has the further advantage that it can burn natural uranium, thorium and even boron.

  2. Results of the Interlaboratory Exercise CNS/CIEMAT-2008 among Environmental Radioactivity Laboratories (Phosphogypsum); Evaluacion de la Intercomparacion CSN/CIEMAT-2008 entre Laboratorios Nacionales de Radiactividad Ambiental (Fosfoyeso)

    Energy Technology Data Exchange (ETDEWEB)

    Romero, M. L.; Barrera, M.; Valino, F.

    2010-05-27

    The document describes the outcome of the CSN/CIEMAT-2008 interlaboratory test comparison among environmental radioactivity laboratories. The exercise was organised according to the ISO-43 and the ISO/IUPAC/AOAC. Aphosphogypsum material was used as a test sample, in an attempt to evaluate the performance of the laboratories analyzing NORM (Naturally-Occurring Radioactive Materials). The analysis required were: U-238, Th-234, U-234, Th-230, Ra-226, Pb-214, Bi-214, Pb-210, Po-210, Th-232 and U-235, and also gross alpha and gross beta activities. Reference values have been established according to the method of consensus of expert laboratories, with four international laboratories of credited experience: IAEA Seibersdorf, IAEA MEL, IRSN-Orsay and Sta.Teresa ENEA. The results of the exercise were computed for 34 answering laboratories and their analytical performance was assessed using the z-score. Robust statistics of the participants results was applied to obtain the median and standard deviation, to achieve a more complete and objective study of the laboratories performance. The exercise has shown an homogeneous behaviour of laboratories, being statistical parameters from the results close to the assigned Reference Values. Participant laboratories have demonstrated their ability to determine natural radionuclides in phosphogypsum samples (NORM material) with a satisfactory quality level. The scheme has also allowed examining the capability of laboratories to determine the activities of natural radionuclides at the equilibrium. (Author) 10 refs.

  3. Radiometric research in soils cultivated with sugar cane in Pernambuco - Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Santos Junior, Otavio P. dos; Santos Junior, Jose A. dos; Amaral, Romilton dos S.; Menezes, Romulo S.C.; Santos, Josineide M.N. dos; Silva, Arykerne N.C. da; Fernandez, Zahily H.; Rojas, Lino A.V.; Damascena, Kennedy F.R.; Silva, Rafael R.; Milan, Marvic O., E-mail: rodriguesrs19@gmail.com, E-mail: otavio.santos@vitoria.ifpe.edu.br, E-mail: lino.valcarcel@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco (IFPE), Vitoria de Santo Antao, PE (Brazil); Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear, La Habana (Cuba); Instituto Superior de Tecnologias y Ciencias Aplicadas Quinta de los Molinos, La Habana (Cuba)

    2017-11-01

    The state of Pernambuco is representative of Northeastern Brazil, with respect to the variability of climatic conditions, soil types, soil cover, as well as land use. The state is subdivided into five regions: Recife Metropolitan Region, Sao Francisco, Sertao, Agreste and Zona da Mata (Atlantic Forest Region). Each region presents peculiar climatic and economic activities. The Atlantic Forest region, the focus of this study, presents a humid tropical climate and is characterized by large farms and the monoculture of sugarcane. In this scenario, a radioecological investigation was carried out to determine the radiometric potential from the analysis of forty-five soil samples, collected in five soil profiles, to a depth of 60 cm. A non-destructive method was adopted for the radiometric analysis, using High- Resolution Gamma Spectrometry with an HPGe-Be type detector. This method allowed the determination of specific activities of U-238, Th-232 and K-40 in the soil samples. The results will be used as a basis for the determination of a reference value for the natural radioactivity of these soils, to predict the existence of possible environmental impacts resulting from their use for the cultivation of sugar cane, as well as to contribute to guarantee the safety of food crops cultivated in this region. (author)

  4. Knowledge gaps in relation to radionuclide levels and transfer to wild plants and animals, in the context of environmental impact assessments, and a strategy to fill them

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J.E. (ed.); Gjelsvik, R. (Norwegian Radiation Protection Authority (Norway)); Saxen, R.; Mattila, J. (STUK - Radiation and Nuclear Safety Authority (Finland))

    2009-01-15

    International activities with regards the development of methods for assessing impacts on the environment from ionising radiation have been substantial in recent years. In developing these methods, there are requirements (i) to determine the transfer of radionuclides within ecosystems and (ii) to determine background dose-rates arising from the presence of naturally occurring radionuclides, in a satisfactory manner. It has quickly become evident that fulfilling these 2 requirements is not entirely straightforward reflecting a lack of data in many cases. This report specifies exactly where these data-gaps lie through analyses of data generated from the most recent studies conducted internationally on this topic. It is evident that information is limited for numerous radionuclides from U-238 and Th-232 decay series and notably, in view of its importance as a contributor to dose-rates in plants and animals, Po-210. The simple way to rectify these data deficiencies is to organise target field campaigns focusing on particular species and radionuclides where information is lacking. To this end, field sampling has been conducted in a semi-natural mountain ecosystem in Norway and freshwater aquatic systems in Finland. It is envisaged that the data derived from the studies briefly described in this report will provide fundamental information for our understanding of the behaviour and fate of natural decay series radionuclides in terrestrial and aquatic systems and provide the basis for more robust way. (au)

  5. Estimate on external effective doses received by the Iranian population from environmental gamma radiation sources

    Energy Technology Data Exchange (ETDEWEB)

    Roozitalab, J.; Reza deevband, M.; Rastkhah, N. [National Radiation Protection Dept. Atomic Energy Organization (Iran, Islamic Republic of); Sohrabi, M. [Intenatinal atomic Energy Agency, Vienna (Austria)

    2006-07-01

    Concentration of natural radioactive materials, especially available U 238, Ra 226, Th 232, and K 40 in construction materials and soil, as well as absorb dose from cosmic rays, is the most important source of the people for effective doses from the environment radiation. In order to evaluate external effective dose, it has been carried out more than 1000 measurements in 36 cities by sensitive dosimeters to environmental gamma radiation for indoor and outdoor conditions in residential areas; which its results show that range of gamma exposure for inside of buildings in Iran is 8.7-20.5 {mu}R/h, and outdoor environments of different cities is 7.9-20.6 {mu}R/h, which their mean value are 14.33 and 12.62 {mu}R/h respectively. Meanwhile, it has been estimated that beam-absorbing ratio between indoor and outdoor in measured environments is 1.55, except contribution of cosmic rays. This studies show that average effective dose for each Iranian person from environmental gamma is 96.9 n Sv/h, and annually effective dose for every person is 0.848 mSv. (authors)

  6. Geothermie

    Science.gov (United States)

    Zahoransky, Richard; Allelein, Hans-Josef; Bollin, Elmar; Oehler, Helmut; Schelling, Udo

    Mit zunehmender Tiefe nimmt die Erdtemperatur zu. Im flüssigen inneren Erdkern herrschen Temperaturen von 3000 bis 6000 K. Durch Wärmeleitung entsteht ein Wärmestrom zur kalten Erdoberfläche. Nur an wenigen Stellen in der oberen Erdkruste wird Erdwärme durch Wasserund Dampfströmungen an die Oberfläche befördert. Die vom Erdkern abgegebene Wärme wird zu etwa 60 % durch den im Kern ablaufenden radioaktiven Zerfall, im Wesentlichen der Elemente Kalium K-40, Thorium Th-232, Uran U-235 und U-238, gespeist. Der Rest der Wärme zählt zur Ursprungswärme, die einmal bei der Erdentstehung entstand und zum anderen durch umgewandelte kinetische Energie großer Meteoriteneinschläge sowie permanent durch die Erstarrung des Erdkernmaterials in der Übergangszone vom flüssigen zum festen Kern freigesetzt wird. Die Erstarrung setzt Kristallisationswärme (Latentwärme) frei. Die Geothermie ist für menschliche Zeitvorstellungen unerschöpflich, obwohl sich langfristig die Erde abkühlt.

  7. Radionuclide inventories for the F- and H-area seepage basin groundwater plumes

    Energy Technology Data Exchange (ETDEWEB)

    Hiergesell, Robert A [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kubilius, Walter P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-01

    Within the General Separations Areas (GSA) at the Savannah River Site (SRS), significant inventories of radionuclides exist within two major groundwater contamination plumes that are emanating from the F- and H-Area seepage basins. These radionuclides are moving slowly with groundwater migration, albeit more slowly due to interaction with the soil and aquifer matrix material. The purpose of this investigation is to quantify the activity of radionuclides associated with the pore water component of the groundwater plumes. The scope of this effort included evaluation of all groundwater sample analyses obtained from the wells that have been established by the Environmental Compliance & Area Completion Projects (EC&ACP) Department at SRS to monitor groundwater contamination emanating from the F- and H-Area Seepage Basins. Using this data, generalized groundwater plume maps for the radionuclides that occur in elevated concentrations (Am-241, Cm-243/244, Cs-137, I-129, Ni-63, Ra-226/228, Sr-90, Tc-99, U-233/234, U-235 and U-238) were generated and utilized to calculate both the volume of contaminated groundwater and the representative concentration of each radionuclide associated with different plume concentration zones.

  8. Radio-Ecological Situation in the Area of the Priargun Production Mining and Chemical Association - 13522

    Energy Technology Data Exchange (ETDEWEB)

    Semenova, M.P.; Seregin, V.A.; Kiselev, S.M.; Titov, A.V. [FSBI SRC A.I. Burnasyan Federal Medical Biophysical Center of FMBA of Russia, Zhivopisnaya Street, 46, Moscow (Russian Federation); Zhuravleva, L.A. [FSHE ' Centre of Hygiene and Epidemiology no. 107' under FMBA of Russia (Russian Federation); Marenny, A.M. [Ltd ' Radiation and Environmental Researches' (Russian Federation)

    2013-07-01

    'The Priargun Production Mining and Chemical Association' (hereinafter referred to as PPMCA) is a diversified mining company which, in addition to underground mining of uranium ore, carries out refining of such ores in hydrometallurgical process to produce natural uranium oxide. The PPMCA facilities are sources of radiation and chemical contamination of the environment in the areas of their location. In order to establish the strategy and develop criteria for the site remediation, independent radiation hygienic monitoring is being carried out over some years. In particular, this monitoring includes determination of concentration of the main dose-forming nuclides in the environmental media. The subjects of research include: soil, grass and local foodstuff (milk and potato), as well as media of open ponds (water, bottom sediments, water vegetation). We also measured the radon activity concentration inside surface workshops and auxiliaries. We determined the specific activity of the following natural radionuclides: U-238, Th-232, K-40, Ra-226. The researches performed showed that in soil, vegetation, groundwater and local foods sampled in the vicinity of the uranium mines, there is a significant excess of {sup 226}Ra and {sup 232}Th content compared to areas outside the zone of influence of uranium mining. The ecological and hygienic situation is as follows: - at health protection zone (HPZ) gamma dose rate outdoors varies within 0.11 to 5.4 μSv/h (The mean value in the reference (background) settlement (Soktui-Molozan village) is 0.14 μSv/h); - gamma dose rate in workshops within HPZ varies over the range 0.14 - 4.3 μSv/h. - the specific activity of natural radionuclides in soil at HPZ reaches 12800 Bq/kg and 510 Bq/kg for Ra-226 and Th-232, respectively. - beyond HPZ the elevated values for {sup 226}Ra have been registered near Lantsovo Lake - 430 Bq/kg; - the radon activity concentration in workshops within HPZ varies over the range 22 - 10800 Bq

  9. Studies of transport pathways of Th, U, rare earths, Ra-228, and Ra-226 from soil to plants and farm animals: Final progress report, 1983-1988

    Energy Technology Data Exchange (ETDEWEB)

    Linsalata, P

    1988-07-01

    This report consists of three parts. Part 1 discusses a field study conducted in an area of enhanced, natural radioactivity to assess the soil to edible vegetable concentration ratios (CR = concentration in dry vegetable/concentration in dry soil) of Th-232, Th-230, Ra-226, Ra-228, and the light rare earth elements (REE's), La, Ce, and Nd. Twenty-eight soil, and approximately 42 vegetable samples consisting of relatively equal numbers of seven varieties, were obtained from 11 farms on the Pocos de Caldas Plateau in the state of Minas Gerais, Brazil. This region is the site of a major natural analogue study to assess the mobilization and retardation processes affecting thorium and the REE's at the Morro do Ferro ore body, and uranium series radionuclides at the Osamu Utsumi open pit uranium mine. Thorium (IV) serves as a chemical analogue for quadrivalent plutonium, the light REE's (III) as chemical analogues for trivalent americium and curium, and uranium (VI) as an analogue for transuranics with stable oxidation states above IV, e.g., Pu(VI). Part 2 includes our final measurement results for naturally occurring light rare earth elements (REE's include La, Ce, Nd, and SM), U-series and Th-series radionuclides in adult farm animal tissues, feeds and soils. Our findings on soil-to-tissue concentration ratios (CR's) and the comparative behavior of these elements in farm animals raised under natural conditions by local farmers are presented. Part 3 summarizes our findings to date on the distribution and mobilization of Th-232, light rare earth elements (LREE), U-238 and Ra-228 in the MF basin. Estimates of first order, present day, mobilization rate constants resulting from ground water solubilization and seepage/stream transport are calculated using revised inventory estimates for the occurrence of these elements in the ore body and annual flux estimates for the transport of these elements away from the ore body. 151 refs., 20 figs., 40 tabs.

  10. Orientating investigation to Polonium-210 and other radionuclides in Dutch aquatic ecosystems. Orienterend onderzoek naar Polonium-210 en andere radionucliden in Nederlandse aquatische ecosystemen

    Energy Technology Data Exchange (ETDEWEB)

    Koester, H.W.; Marwitz, P.A. (Rijksinstituut voor Volksgezondheid en Milieuhygiene, Bilthoven (Netherlands)); Berger, G.W. (Netherlands Inst. for Sea Research, Den Burg (Netherlands)); Weers, A.W. van (Netherlands Energy Research Foundation, Petten (Netherlands)); Hagel, P. (RIVO (Netherlands)); Nieuwenhuize, J. (DIHO (Netherlands))

    1990-08-01

    In 1985/86 reconnaissance investigations were carried out of Po-210, Pb-210, Ra-226, Th-230 of the U-238 series, and of Th-232 and its daughter Th-228. In the lower reaches of the Rhine, Westerschelde, and Hoogoven(furnace)-channel concentrations were markedly elevated. The average Po-210 concentrations of these waters were between 3-4 Bq.m{sup -3} dissolved in water, between 200-500 Bq.kg{sup -1} in dry suspended matter, between 300-400 Bq.kg{sup -1} in mussels dry matter. These elevated levels could be ascribed to emissions on these waters by the phosphate rock and iron-ore-processing industries. In bottom sediment of waterways or of docks close to these industries Pb-210 and Po-210 concentrations varied from 150 to 750 Bq.kg{sup -1} dry sediment. The lowest average Po-210 concentrations were found in the Oosterschelde: 0.8 Bq.m{sup -3} dissolved in water, 70 Bq.kg{sup -1} in dry suspended matter, 100 Bq.kg{sup -1} in mussels dry matter. It was found that several organisms incorporate Po-210 more strongly than the other natural radionuclides. Po-210 also contributes most to the radiation burden caused by the consumption of fish products, in particular mussels and shrimps. Consumption of 1 kg. a{sup -1} of shrimps from the Oosterschelde or from the coastal area causes respectively a radiation exposure of 10 {mu}Sv.a{sup -1} or 30 {mu}Sv.a{sup -1}. This study points out the necessity for further studies of the emissions of Po-210 and other U-238 daughters and their dispersal and/or accumulation in the aquatic environment. Furthermore it is important to identify critical groups with respect to the radiation exposure caused by the consumption of mussels and other fish products, and the contribution to this radiation exposure by the industries. (author). 43 refs.; 58 figs.; 52 tabs.

  11. Depletion Analysis of Modular High Temperature Gas-cooled Reactor Loaded with LEU/Thorium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sonat Sen; Gilles Youinou

    2013-02-01

    Thorium based fuel has been considered as an option to uranium-based fuel, based on considerations of resource utilization (Thorium is more widely available when compared to Uranium). The fertile isotope of Thorium (Th-232) can be converted to fissile isotope U-233 by neutron capture during the operation of a suitable nuclear reactor such as High Temperature Gas-cooled Reactor (HTGR). However, the fertile Thorium needs a fissile supporter to start and maintain the conversion process such as U-235 or Pu-239. This report presents the results of a study that analyzed the thorium utilization in a prismatic HTGR, namely Modular High Temperature Gas-Cooled Reactor (MHTGR) that was designed by General Atomics (GA). The collected for the modeling of this design come from Chapter 4 of MHTGR Preliminary Safety Information Document that GA sent to Department of Energy (DOE) on 1995. Both full core and unit cell models were used to perform this analysis using SCALE 6.1 and Serpent 1.1.18. Because of the long mean free paths (and migration lengths) of neutrons in HTRs, using a unit cell to represent a whole core can be non-trivial. The sizes of these cells were set to match the spectral index between unit cell and full core domains. It was found that for the purposes of this study an adjusted unit cell model is adequate. Discharge isotopics and one-group cross-sections were delivered to the transmutation analysis team. This report provides documentation for these calculations

  12. Evaluation of High Energy Nuclear Data of Importance for Use in Accelerator and Space Technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Ouk

    2005-10-15

    New evaluation were performed for neutron- and proton-induced reactions for energies up to 250 400 MeV on C-12, N-14, O-16, Al-27, Si-28, Ca-40, Ar-40, Fe-54,58, Ni-64, Cu-63,65, Zr-90, Pb-208, Th-232, U-233,234,236, and Cm-243246. The evaluated results are then applied to the accelerator and space technology. A set of optical model parameters were optimized by searching a number of adjustable coefficients with the Simulated Annealing(SA) method for the spherical nuclei. A parameterization of the empirical formula was proposed to describe the proton-nucleus non-elastic cross sections of high-priority elements for space shielding purpose for proton energies from reaction threshold up to 400 MeV, which was then implemented into the fast scoping space shielding code CHARGE, based on the results of the optical model analysis utilizing up-to-date measurements. For proton energies up to 400 MeV covering most of the incident spectrum for trapped protons and solar energetic particle events, energy-angle spectra of secondary neutrons produced from the proton-induced neutron production reaction were prepared. The evaluated cross section set was applied to the thick target yield (TTY) and promp radiation benchmarks for the accelerator shielding. As for the assessment of the radiological impact of the accelerator to the environment, relevant nuclear reaction cross sections for the activation of the air were recommended among the author's evaluations and existing library based on the available measurements.

  13. Fuel Summary Report: Shippingport Light Water Breeder Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Illum, D.B.; Olson, G.L.; McCardell, R.K.

    1999-01-01

    The Shippingport Light Water Breeder Reactor (LWBR) was a small water cooled, U-233/Th-232 cycle breeder reactor developed by the Pittsburgh Naval Reactors to improve utilization of the nation's nuclear fuel resources in light water reactors. The LWBR was operated at Shippingport Atomic Power Station (APS), which was a Department of Energy (DOE) (formerly Atomic Energy Commission)-owned reactor plant. Shippingport APS was the first large-scale, central-station nuclear power plant in the United States and the first plant of such size in the world operated solely to produce electric power. The Shippingport LWBR was operated successfully from 1977 to 1982 at the APS. During the five years of operation, the LWBR generated more than 29,000 effective full power hours (EFPH) of energy. After final shutdown, the 39 core modules of the LWBR were shipped to the Expended Core Facility (ECF) at Naval Reactors Facility at the Idaho National Engineering and Environmental Laboratory (INEEL). At ECF, 12 of the 39 modules were dismantled and about 1000 of more than 17,000 rods were removed from the modules of proof-of-breeding and fuel performance testing. Some of the removed rods were kept at ECF, some were sent to Argonne National Laboratory-West (ANL-W) in Idaho and some to ANL-East in Chicago for a variety of physical, chemical and radiological examinations. All rods and rod sections remaining after the experiments were shipped back to ECF, where modules and loose rods were repackaged in liners for dry storage. In a series of shipments, the liners were transported from ECF to Idaho Nuclear Technology Engineering Center (INTEC), formerly the Idaho Chemical Processing Plant (ICPP). The 47 liners containing the fully-rodded and partially-derodded core modules, the loose rods, and the rod scraps, are now stored in underground dry wells at CPP-749.

  14. Activity of natural radionuclides and their contribution to the absorbed dose in the fish cubera snapper (lutjanus cyanopterus, cuvier, 1828 on the coast of Ceara, Brazil

    Directory of Open Access Journals (Sweden)

    Wagner de S. Pereira

    2010-01-01

    Full Text Available A methodology was developed for converting the activity concentration of radionuclides (Bq kg-1 into absorbed dose rate (Gy y-1, aiming an approach to environmental radioprotection based on the concept of standard dose limit. The model considers only the internal absorbed dose rate. This methodology was applied to the cubera snapper fish (Lutjanus cyanopterus, Cuvier, 1828 caught off the coast of Ceará. The natural radionuclides considered were uranium-238, radium-226, lead-210, thorium-232 and radium-228. The absorbed dose rates were calculated for individual radionuclides and the type of emitted radiation. The average dose rate due to these radionuclides was 5.36 µGy y-1, a value six orders of magnitude smaller than the threshold value of absorbed dose rate used in this study (3.65 10³ mGy y-1, and similar to that found in the literature for benthic fish. Ra-226 and U-238 contributed 67% and 22% of the absorbed dose rate, followed by Th-232 with 10%. Ra-228 and Pb-210, in turn, accounted for less than 1% of the absorbed dose rate. This distribution is somewhat different from that reported in the literature, where the Ra-226 accounts for 86% of the absorbed dose rate.Visando a radioproteção ambiental, baseada no conceito de limite de taxa de dose absorvida, foi desenvolvida uma metodologia de conversão da concentração de atividade de radionuclídeos (Bq kg-1 em taxa de dose absorvida (Gy a-1. O modelo considera apenas a taxa de dose absorvida interna. Essa metodologia foi aplicada ao peixe vermelho-caranho (Lutjanus cyanopterus, Cuvier, 1828 capturado na costa do Ceará e aos radionuclídeos naturais: urânio-238, rádio-226, chumbo-210, tório-232 e rádio-228. As taxas de dose absorvidas foram calculadas por radionuclídeo e por tipo de radiação emitida. A taxa de dose média devida a esses radionuclídeos foi de 5.36 µGy a-1, valor seis ordens de grandeza menor que o valor de limite de taxa de dose absorvida utilizada no presente

  15. Role of radiation dating technique - one example

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Shigueo [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica; Etchevarne, Carlos A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Fac. de Filosofia e Ciencias Humanas. Dept. Antropologia e Etnologia; Cano, Nilo F.; Munita, C.S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-07-01

    Full text: The great majority of archaeological or geological dating technique is based on radiation effect. The so called radioactivity method uses radioactive decays of elements. This is the case of the well known radiocarbon or carbon-14 method. Also the method of relating daughter nucleus to decaying nucleus, as in K-40/Ar-40, Th- 230/U-234, etc. Here we will concentrate in the method based on energy deposition in a solid by radiation from the disintegration of U-series and Th-series. {beta}-rays emitted by the decay of K-40 into Ca-40 (80%) and Ar-40 (11%) also contributes. The role of {alpha}, {beta} and {gamma} radiation emitted by radionuclides in the U-238 and Th-232 series and of {beta} rays from the decay of K-40, all of them in the soil irradiate anything in their course. For dating, we can have sediments as well as potteries produced by ancient people and became buried. The important process consists in transferring a fraction of the energy of radiation to the solid, mainly liberating electrons from valence band to conduction band and from there to traps. In many case the energy of the radiation is used to create defects which in turn create energy levels (traps) in the forbidden gap (or energy gap). There are three ways to recover the energy stored in the solid: (1) by emission of light optically stimulated (OSL), (2) by emission of light thermally stimulated (TL), (3) by microwave absorption (EPR or ESR). Using these techniques among several applications, we will present one to find the first settlers in the northeaster region of Brazil. (author)

  16. Phosphategypsum wastes in Venice lagoon. Radiological impact; Le discariche di fosfogessi nella laguna di Venezia. Valutazioni preliminari dell'impatto radiologico

    Energy Technology Data Exchange (ETDEWEB)

    Belli, M; Blasi, M; Guogang, J.; Rosamilia, S.; Sansone, U. [Agenzia Nazionale per la Protezione dell' Ambiente, Rome (Italy); Biancotto, R.; Bidoli, P.; Sepulcri, D. [Agenzia Regionale di Prevenzione e Protezione del Veneto, Venice (Italy). Dipt. provinciale di Venezia; Cavolo, F. [Smilax, Mira, VE (Italy)

    2000-07-01

    The phosphoric minerals utilized in phosphoric acid production, presents high concentrations of radioactive materials: U238, Th 232, K 40. The phosphogypsum is the waste material obtained in the phosphoric acid production in wet process. This type of production method is employed for many years in Venice lagoon (Porto Marghera chemical plants). In this paper are reported evaluations of radiological impact on aquatic environment of lagoon. [Italian] Con il termine di fosfogessi si intende comunemente il materiale di risulta che si ottiene nella produzione di acido fosforico attraverso la via umida (attacco acido). Questa tipologia di produzione che ha operato per diversi decenni a Porto Marghera, e' finalizzata allo scopo di ottenere acido fosforico principalmente per l'industria dei fertilizzanti e quindi come prodotto intermedio per la chimica e per le preparazioni alimentari. Il fosforo, elemento principale della reazione, era ricavato da rocce fosfatiche di origine sedimentaria marina provenienti per lo piu' dall'Africa settentrionale. Il sistema produttivo utilizzato negli impianti di Porto Marghera era basato su una reazione principale, che partendo dal minerale attraverso un attacco acido, produceva acido fosforico: Ca{sub 3}(PO{sub 4}){sub 2} (Minerale Fosforico) + 3H{sub 2}SO{sub 4} (Acido Solforico) + 3H{sub 2}O (Acqua) {yields} 2H{sub 3}PO{sub 4} (Acido fosforico) + 3CaSO{sub 4}H{sub 2}O (Solfato di calcio (gesso)). In particolare il minerale era preventivamente macinato e vagliato, quindi si procedeva alla sua miscelazione con l'acido fosforico ed alla successiva reazione del composto ottenuto.

  17. High resolution analysis of uranium and thorium concentration as well as U-series isotope distributions in a Neanderthal tooth from Payre (Ardèche, France) using laser ablation ICP-MS

    Science.gov (United States)

    Grün, Rainer; Aubert, Maxime; Joannes-Boyau, Renaud; Moncel, Marie-Hélène

    2008-11-01

    We have mapped U ( 238U) and Th ( 232Th) elemental concentrations as well as U-series isotope distributions in a Neanderthal tooth from the Middle Palaeolithic site of Payre using laser ablation ICP-MS. The U-concentrations in an enamel section varied between 1 and 1500 ppb. The U-concentration maps show that U-migration through the external enamel surface is minute, the bulk of the uranium having migrated internally via the dentine into the enamel. The uranium migration and uptake is critically dependent on the mineralogical structure of the enamel. Increased U-concentrations are observed along lineaments, some of which are associated with cracks, and others may be related to intra-prismatic zones or structural weaknesses reaching from the dentine into the enamel. The uranium concentrations in the dentine vary between about 25,000 and 45,000 ppb. Our systematic mapping of U-concentration and U-series isotopes provides insight into the time domain of U-accumulation. Most of the uranium was accumulated in an early stage of burial, with some much later overprints. None of the uranium concentration and U-series profiles across the root of the tooth complied with a single stage diffusion-adsorption (D-A) model that is used for quality control in U-series dating of bones and teeth. Nevertheless, in the domains that yielded the oldest apparent U-series age estimates, U-leaching could be excluded. This means that the oldest apparent U-series ages of around 200 ka represent a minimum age for this Neanderthal specimen. This is in good agreement with independent age assessments (200-230 ka) for the archaeological layer, in which it was found. The Th elemental concentrations in the dental tissues were generally low (between about 1 and 20 ppb), and show little relationship with the nature of the tissue.

  18. Ecosystem element transport model for Lake Eckarfjaerden

    Energy Technology Data Exchange (ETDEWEB)

    Konovalenko, L.; Bradshaw, C. [The Department of Ecology, Environment and Plant Sciences, Stockholm University (Sweden); Andersson, E.; Kautsky, U. [Swedish Nuclear Fuel and Waste Management Co. - SKB (Sweden)

    2014-07-01

    The ecosystem transport model of elements was developed for Lake Eckarfjaerden located in the Forsmark area in Sweden. Forsmark has currently a low level repository (SFR) and a repository for spent fuel is planned. A large number of data collected during site-investigation program 2002-2009 for planning the repository were available for the creation of the compartment model based on carbon circulation, physical and biological processes (e.g. primary production, consumption, respiration). The model is site-specific in the sense that the food web model is adapted to the actual food web at the site, and most estimates of biomass and metabolic rates for the organisms and meteorological data originate from site data. The functional organism groups of Lake Eckarfjaerden were considered as separate compartments: bacterio-plankton, benthic bacteria, macro-algae, phytoplankton, zooplankton, fish, benthic fauna. Two functional groups of bacteria were taken into account for the reason that they have the highest biomass of all functional groups during the winter, comprising 36% of the total biomass. Effects of ecological parameters, such as bacteria and algae biomass, on redistribution of a hypothetical radionuclide release in the lake were examined. The ecosystem model was used to estimate the environmental transfer of several elements (U, Th, Ra) and their isotopes (U-238, U-234,Th-232, Ra-226) to various aquatic organisms in the lake, using element-specific distribution coefficients for suspended particle and sediment. Results of chemical analyses of the water, sediment and biota were used for model validation. The model gives estimates of concentration factors for fish based on modelling rather on in situ measurement, which reduces the uncertainties for many radionuclides with scarce of data. Document available in abstract form only. (authors)

  19. Illicit Trafficking of Natural Radionuclides

    Science.gov (United States)

    Friedrich, Steinhäusler; Lyudmila, Zaitseva

    2008-08-01

    Natural radionuclides have been subject to trafficking worldwide, involving natural uranium ore (U 238), processed uranium (yellow cake), low enriched uranium (20% U 235), radium (Ra 226), polonium (Po 210), and natural thorium ore (Th 232). An important prerequisite to successful illicit trafficking activities is access to a suitable logistical infrastructure enabling an undercover shipment of radioactive materials and, in case of trafficking natural uranium or thorium ore, capable of transporting large volumes of material. Covert en route diversion of an authorised uranium transport, together with covert diversion of uranium concentrate from an operating or closed uranium mines or mills, are subject of case studies. Such cases, involving Israel, Iran, Pakistan and Libya, have been analyzed in terms of international actors involved and methods deployed. Using international incident data contained in the Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO) and international experience gained from the fight against drug trafficking, a generic Trafficking Pathway Model (TPM) is developed for trafficking of natural radionuclides. The TPM covers the complete trafficking cycle, ranging from material diversion, covert material transport, material concealment, and all associated operational procedures. The model subdivides the trafficking cycle into five phases: (1) Material diversion by insider(s) or initiation by outsider(s); (2) Covert transport; (3) Material brokerage; (4) Material sale; (5) Material delivery. An Action Plan is recommended, addressing the strengthening of the national infrastructure for material protection and accounting, development of higher standards of good governance, and needs for improving the control system deployed by customs, border guards and security forces.

  20. Scoping survey of perceived concerns, issues, and problems for near-surface disposal of FUSRAP waste

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.E.; Gilbert, T.L.

    1982-12-01

    This report is a scoping summary of concerns, issues, and perceived problems for near-surface disposal of radioactive waste, based on a survey of the current literature. Near-surface disposal means land burial in or within 15 to 20 m of the earth's surface. It includes shallow land burial (burial in trenches, typically about 6 m deep with a 2-m cap and cover) and some intermediate-depth land burial (e.g., trenches and cap similar to shallow land burial, but placed below 10 to 15 m of clean soil). Proposed solutions to anticipated problems also are discussed. The purpose of the report is to provide a better basis for identifying and evaluating the environmental impacts and related factors that must be analyzed and compared in assessing candidate near-surface disposal sites for FUSRAP waste. FUSRAP wastes are of diverse types, and their classification for regulatory purposes is not yet fixed. Most of it may be characterized as low-activity bulk solid waste, and is similar to mill tailings, but with somewhat lower average specific activity. It may also qualify as Class A segregated waste under the proposed 10 CFR 61 rules, but the parent radionuclides of concern in FUSRAP (primarily U-238 and Th-232) have longer half-lives than do the radionuclides of concern in most low-level waste. Most of the references reviewed deal with low-level waste or mill tailings, since there is as yet very little literature in the public domain on FUSRAP per se.

  1. Improved Fission Neutron Data Base for Active Interrogation of Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Pozzi, Sara; Czirr, J. Bart; Haight, Robert; Kovash, Michael; Tsvetkov, Pavel

    2013-11-06

    This project will develop an innovative neutron detection system for active interrogation measurements. Many active interrogation methods to detect fissionable material are based on the detection of neutrons from fission induced by fast neutrons or high-energy gamma rays. The energy spectrum of the fission neutrons provides data to identify the fissionable isotopes and materials such as shielding between the fissionable material and the detector. The proposed path for the project is as follows. First, the team will develop new neutron detection systems and algorithms by Monte Carlo simulations and bench-top experiments. Next, They will characterize and calibrate detection systems both with monoenergetic and white neutron sources. Finally, high-fidelity measurements of neutron emission from fissions induced by fast neutrons will be performed. Several existing fission chambers containing U-235, Pu-239, U-238, or Th-232 will be used to measure the neutron-induced fission neutron emission spectra. The challenge for making confident measurements is the detection of neutrons in the energy ranges of 0.01 – 1 MeV and above 8 MeV, regions where the basic data on the neutron energy spectrum emitted from fission is least well known. In addition, improvements in the specificity of neutron detectors are required throughout the complete energy range: they must be able to clearly distinguish neutrons from other radiations, in particular gamma rays and cosmic rays. The team believes that all of these challenges can be addressed successfully with emerging technologies under development by this collaboration. In particular, the collaboration will address the area of fission neutron emission spectra for isotopes of interest in the advanced fuel cycle initiative (AFCI).

  2. Quantifying rind formation and chemical weathering rates in weathering clasts with uranium-series isotopes: a case study from Basse-Terre Island, Guadeloupe

    Science.gov (United States)

    Ma, L.; Chabaux, F. J.; Pelt, E.; Granet, M.; Sak, P. B.; Gaillardet, J.; Lebedeva, M.; Brantley, S. L.

    2011-12-01

    Weathering of tropical volcanic islands is rapid because of the reactive nature of the volcanic rock and the hot humid climate. In the tropics, rock fragments in the regolith zone commonly form alteration rinds. Weathering rinds are excellent samples to understand key chemical weathering processes. To quantify rock weathering rates in a tropical climate and to understand the environmental factors that control these rates, we combined a novel U-series isotopic technique with chemical and electron microprobe analyses to study weathering rinds formed at Basse-Terre Island, Guadeloupe. U-series isotopes and element concentrations were analyzed in a basaltic/andesitic weathering rind collected from the Bras David watershed on Basse-Terre Island. From the clast, core and rind samples were obtained by drilling along two linear profiles. Elemental profiles reveal that elemental loss varies in the order of Ca, Na, Sr > K, Mg, Rb > Mn > Si > Ba > Al > Fe, and Ti =0 across the core-rind interface, consistent with relative reactivity of phases in the clast from plagioclase ≈ pyroxene ≈ glass matrix > apatite > ilmenite. Elemental profiles also reveal conservative behavior of Th and external addition of U into the rind during clast weathering. Measured (234U/238U) activity ratios of the rind samples (1.001 to 1.031) are mostly higher than the core samples (average at ~1.003). Measured (238U/232Th) and (230Th/232Th) activity ratios of the core and rind samples range from 0.973 to 1.817, and 0.971 to 1.375, respectively. Most importantly, both (238U/232Th) and (230Th/232Th) activity ratios increase systematically from the core into the weathering rind for the two profiles. The elemental profiles and electronic microprobe observations suggest that weathering reactions include dissolution of pyroxene, plagioclase, and glass matrix, and formation of Fe oxyhydroxides, gibbsite and minor kaolinite. The dissolution of plagioclase leads to significant porosity growth within the rind

  3. Performance assessment requirements for the identification and tracking of transuranic waste intended for disposal at the Waste Isolation Pilot Plant

    Energy Technology Data Exchange (ETDEWEB)

    Snider, C.A. [Department of Energy, Carlsbad, NM (United States); Weston, W.W. [Westinghouse Electric Corp., Carlsbad, NM (United States)

    1997-11-01

    To demonstrate compliance with environmental radiation protection standards for management and disposal of transuranic (TRU) radioactive wastes, a performance assessment (PA) of the Waste Isolation Pilot Plant (WIPP) was made of waste-waste and waste-repository interactions and impacts on disposal system performance. An estimate of waste components and accumulated quantities was derived from a roll-up of the generator/storage sites` TRU waste inventories. Waste components of significance, and some of negligible effect, were fixed input parameters in the model. The results identified several waste components that require identification and tracking of quantities to ensure that repository limits are not exceeded. The rationale used to establish waste component limits based on input estimates is discussed. The distinction between repository limits and waste container limits is explained. Controls used to ensure that no limits are exceeded are identified. For waste components with no explicit repository based limits, other applicable limits are contained in the WIPP Waste Acceptance Criteria (WAC). The 10 radionuclides targeted for identification and tracking on either a waste container or a waste stream basis include Am-241, Pu-238, Pu-239, Pu-240, Pu-242, U-233, U-234, U-238, Sr-90, and Cs-137. The accumulative activities of these radionuclides are to be inventoried at the time of emplacement in the WIPP. Changes in inventory curie content as a function of radionuclide decay and ingrowth over time will be calculated and tracked. Due to the large margin of compliance demonstrated by PA with the 10,000 year release limits specified, the quality assurance objective for radioassay of the 10 radionuclides need to be no more restrictive than those already identified for addressing the requirements imposed by transportation and WIPP disposal operations in Section 9 of the TRU Waste Characterization Quality Assurance Program Plan. 6 refs.

  4. U-series constraints on the Holocene human presence in the Cuatro Cienegas basin, Mexico

    Science.gov (United States)

    Noble, S. R.; Felstead, N.; Gonzalez, S.; Leng, M. J.; Metcalfe, S. E.; Patchett, P. J.

    2010-12-01

    tracer calibrated against gravimetric solutions prepared from Ames high-purity Th metal crystal and CRM 112a U metal ingot rather than natural materials of assumed secular equilibrium. ICP-MS mass bias and Faraday-SEM gain was monitored using CRM 112a and an in-house 229Th-230Th-232Th solution. Most samples have relatively high U contents (~2 ppm U), moderate [230Th/232Th] = 29-44, and initial [234U/238U] ~ 1.92. We obtain an age of 7.24 ± 0.13 ka BP for this trackway based on an average of two samples of the uppermost tufa surface. Depth profiling of one sample shows consistently increasing age downwards (~370 a/cm). [1] Gonzalez, A.H.G. et al., 2006, Ichnos 16, 12-24;[2] Souza, V. et al., 2006, PNAS 103, 6565-6570; [3] Johannesson, K.H. et al., 2004, J.S.Am.Earth Sci. 17, 171-180; [4] Meyer, E. 1973, Ecology 54, 982-995; [5] Minckley, T.A. & Jackson, S. 2008. J. Biogeography 35, 188-190; [6] Edwards, R.L. et al., 1987, EPSL 81, 175-192; [8] Cheng, H. et al., 2000, Chem. Geol. 169, 17-33; [8] Potter, E.K. et al., 2005, EPSL 247, 10-17.

  5. Fe-Mn substance in ocean as reason of regulation radionuclide pollution

    Science.gov (United States)

    Asavin, Alex; Martynov, Konstantin; Konstantinova, Lia

    2013-04-01

    Distribution of radionuclide in marine sediments as yet little studied [Choppin & Wong 1998]. The work mainly focused on effects of nuclear test fallout. In the works are examined isotopes of Pu - 238; Th - 232; U -234;238; Pu - 239,240,241; Am - 241; Np - 237; Cm -244 [Holm 1995]. It has been shown that seems to accumulate radionuclides in marine sediments. In particular, the importance attached to carbonate complexes (corals, etc.). But questions about the possibility of re-mobilization of radionuclide, forms their concentration, their participation in global geochemical cycles in the ocean, remain open. We believe a major factor controlling the distribution of heavy metals is the formation of ocean ferromanganese crusts and nodules hydrogenic at the bottom of the ocean and seamounts. It is likely that the process of formation of Fe-manganese hydrogenic can play a major role in the control of radioactive contamination in the oceanic sediment. At least for the U number of works on the subject [Sherman et al. 2008]. The high sensitivity of the Fe-manganese crust is known to the isotopic composition of lead [Loranger & Zayed 1994, Collen et al 2011]. Recent work [Wilkins etal 2006, Renshaw etal 2009] show a large role; Fe (III)-and Mn (IV)-reducing organisms that anaerobic bacteria in oxidation and therefore changes in mobility systems U and Pu. So much interest is data for sorption of radionuclide on hydroxides Fe and Mn. Unfortunately we are not aware of works on the subject. We have therefore taken their own experimental studies on sorption of radionuclide on natural Fe-Mn crusts (sample from Magellan seamount Pacific ocean) [Martynov et al 2012]. The results showed high sorption ability of material crusts for fixation of radionuclides: U-233, Np-237, Pu-238, Am-241. For all radionuclide experiment absorption has been reached already in the first hour it was 96.0% of total substance radionuclide absorbed from the solution, and after the first day it was reached

  6. 76 FR 31379 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

    Science.gov (United States)

    2011-05-31

    ...-232 (Th-232) and radium-226 (Ra-226) are provided in the revised DP. Small quantities of Th-232 and Ra... Soil DCGLs Addendum Soil DCGLs for Thorium and Radium). The revised DP does not change any previously... area soils. The same isotopes that were present in the Facility's non-FUSRAP areas (namely, those...

  7. Khazar Iodine Production Plant Site Remediation in Turkmenistan. NORM Contaminated Waste Repository Establishment - 12398

    Energy Technology Data Exchange (ETDEWEB)

    Gelbutovskiy, Alexander B.; Cheremisin, Peter I.; Troshev, Alexander V.; Egorov, Alexander J.; Boriskin, Mikhail M.; Bogod, Mikhail A. [JSC ' ECOMET-S' , Sosnoviy Bor, Leningrad region, 188540 (Russian Federation)

    2012-07-01

    Radiation safety provisions for NORM contaminated areas are in use in a number of the former Soviet republics. Some of these areas were formed by absorbed radionuclides at the iodine and bromine extraction sites. As a rule, there are not any plant radiation monitoring systems nor appropriate services to ensure personnel, population and environmental radiation safety. The most hazardous sites are those which are situated in the Caspian Sea coastal zone. The bulk of the accumulated waste is represented by a loose mixture of sand and charcoal, which was basically used as the iodine extraction sorbent. The amounts of these wastes were estimated to be approximately 20,000 metric tons. The waste contamination is mainly composed of Ra-226 (U-238 decay series) and Ra-224, Ra-228 (Th-232 decay series). In 2009, the 'ECOMET-S', a Closed Joint-Stock Company from St. Petersburg, Russian Federation, was authorized by the Turkmenistan government to launch the rehabilitation project. The project includes D and D activities, contaminated areas remediation, collected wastes safe transportation to the repository and its disposal following repository closure. The work at the Khazar chemical plant started in September, 2010. Comprehensive radiological surveys to estimate the waste quantities were carried out in advance. In course of the rehabilitation work at the site of the Khazar chemical plant additional waste quantities (5,000 MT, 10,000 m{sup 3}) were discovered after the sludge was dumped and drained. Disposal volumes for this waste was not provided initially. The additional volume of the construction wastes was required in order to accommodate all the waste to be disposed. For the larger disposal volume the project design enterprise VNIPIET, offered to erect a second wall outside the existing one and this solution was adopted. As of May, 2011, 40,575 m{sup 3} of contaminated waste were collected and disposed safely. This volume represents 96.6% of the initial

  8. DETERMINATION OF REPORTABLE RADIONUCLIDES FOR DWPF SLUDGE BATCH 5 (MACROBATCH 6)

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C.; Bibler, N.; Diprete, D.

    2010-02-04

    The Waste Acceptance Product Specifications (WAPS) 1.2 require that ''The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115''. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production through the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the heel from Tank 40 (Sludge Batch 4 (SB4)), Sludge Batch 5 (SB5) that was transferred to Tank 40 from Tank 51, and H-Canyon Np transfers completed after the start of processing. The blend of sludge in Tank 40 is also referred to as Macrobatch 6 (MB6). This report develops the list of reportable radionuclides and associated activities and determines the radionuclide activities as a function of time

  9. DETERMINATION OF REPORTABLE RADIONUCLIDES FOR DWPF SLUDGE BATCH 4 MACROBATCH 5

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C; Ned Bibler, N; David Diprete, D

    2008-05-30

    The Waste Acceptance Product Specifications (WAPS)1 1.2 require that 'The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115'. As part of the strategy to meet WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production through the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP)2 and Waste Form Qualification Report (WQR)3. However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the previous contents of Tank 40 (Sludge Batch 3) and the sludge that was transferred to Tank 40 from Tank 51. The blend of sludge from Tank 51 and Tank 40 defines Sludge Batch 4 (also referred to as Macrobatch 5 (MB5)). This report develops the list of reportable radionuclides and associated activities and determines the radionuclide activities as a function of time. The DWPF will use this list and the activities

  10. कार्ल्सवर्ग पर्वतश्रेणी के तलछट की विशेषता

    Digital Repository Service at National Institute of Oceanography (India)

    Valsangkar, A.B.

    The sediment coverage in the Carlsberg Ridge is similar in appearance to those in the Mid-Atlantic Ridge. The Carlsberg Ridge sediments show that their sources are continental, biogenic and diagenetic. The sedimentation rate determined by Th232...

  11. Thorium exposure during tungsten inert gas welding with thoriated tungsten electrodes

    DEFF Research Database (Denmark)

    Gäfvert, T.; Pagels, J.; Holm, E.

    2003-01-01

    The exposure to Th-232 from TIG welding with thoriated electrodes has been determined at five different workshops. Welding with both alternating and direct current was investigated. The exposure levels of Th-232 were generally below 10 mBq m(-3) in the breathing zone of the welders. Two samples...... from AC welding showed significant higher exposure levels, probably due to maladjustment of the TIG welding power source. Samples of the respirable fraction of Th-232 from grinding thoriated electrodes were also collected showing exposure levels of 5 mBq m(-3) or lower. A dose estimate has been made...... for two scenarios, one realistic and one with conservative assumptions, showing that the annual committed effective dose from inhalation of Th-232, Th-230, Th-228 and Ra-228, for a full-time TIG welder, in the realistic case is below 0.3 mSv and with conservative assumptions around 1 mSv or lower...

  12. Relativistic Coulomb fission

    Science.gov (United States)

    Norbury, John W.

    Nuclear fission reactions induced by the electromagnetic field of relativistic nuclei are studied for energies relevant to present and future relativistic heavy ion accelerators. Cross sections are calculated for U-238 and Pu-239 fission induced by C-12, Si-28, Au-197, and U-238 projectiles. It is found that some of the cross sections can exceed 10 b.

  13. A certified reference material for radionuclides in the water sample from Irish Sea (IAEA-443)

    DEFF Research Database (Denmark)

    Pham, M.K.; Betti, M.; Povinec, P.P.

    2011-01-01

    A new certified reference material (CRM) for radionuclides in sea water from the Irish sea (IAEA-443) is described and the results of the certification process are presented. Ten radionuclides (3H, 40K, 90Sr, 137Cs, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) have been certified, and informatio...

  14. Исследование фракционирования изотопов урана (234U, 238U) в процессе образования кристаллов льда

    OpenAIRE

    ЯКОВЛЕВ Е.Ю.; КИСЕЛЁВ Г.П.; ДРУЖИНИН С.В.; ЗЫКОВ С.Б.

    2016-01-01

    С момента открытия явления фракционирования четных изотопов урана (эффект Чердынцева-Чалова) среди ряда исследователей сложилось устойчивое убеждение, что разделения изотопной пары урана 234U и 238U в минеральных системах не происходит, и фракционирование возможно только при переходе из твердой фазы в жидкую по причине различной подвижности изотопов. Наблюдаемые избытки изотопа 234U в суммарном уране различных минералов и горных пород, возраст которых значительно превышает период установления...

  15. Total lead (Pb) concentration in oil shale ash samples based on correlation to isotope Pb-210 gamma-spectrometric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Vaasma, T.; Kiisk, M.; Tkaczyk, A.H. [University of Tartu (Estonia); Bitjukova, L. [Tallinn University of Technology (Estonia)

    2014-07-01

    Estonian oil shale consists of organic matter and mineral material and contains various amounts of heavy metals as well as natural radionuclides (from the U-238 and Th-232 series and K-40). Previous research has shown that burning oil shale in the large power plants causes these radionuclides to become enriched in different ash fractions and be partially emitted to the atmosphere via fly ash and flue gases. The activity concentrations (Bq/kg) of these nuclides in different oil shale ash fractions vary significantly. This is influenced by the boiler parameters and combustion conditions - prevailing temperatures, pressure, ash circulating mechanisms, fly ash particle size, chemical composition of ash and coexistence of macro and micro components. As with radionuclides, various heavy metals remain concentrated in the ash fractions and are released to the atmosphere (over 20 tons of Pb per year from Estonian oil shale power plants). Lead is a heavy metal with toxic influence on the nervous system, reproductive system and different organs in human body. Depending on the exposure pathways, lead could pose a long term health hazard. Ash samples are highly heterogeneous and exhibit great variability in composition and particle size. Determining the lead concentration in ash samples by modern methods like inductively coupled plasma mass spectroscopy (ICP-MS), flame atomic absorption spectrometry (FAAS), graphite furnace atomic absorption spectroscopy (GFAAS) and other techniques often requires time consuming, multistage and complex chemical sample preparation. The list of possible methods to use is lengthy, but it is a challenge to choose a suitable one to meet measurement needs and practical considerations. The detection limits, capital costs and maintenance expenses vary between the instruments. This work presents the development of an alternative measurement technique for our oil shale ash samples. Oil shale ash was collected from different boilers using pulverized fuel

  16. Status of Geothermal Research and Development in the World Situation mondiale de la Recherche et du Développement géothermiques

    Directory of Open Access Journals (Sweden)

    Fanelli M.

    2006-11-01

    Full Text Available The heat flow observed on the earth's surface (on averageof 59 mW/m2 mainly derives from the heat generated by the decay of radioactive elements (U238, U235, Th232, K40 in the crust. The distribution of heat flow values is closely tied to the phenomena described in theplate tectonicstheory: most of the surface geothermal anomalies and, consequently, the industrially exploitable geothermal areas, are located in correspondence to spreading ridges (geothermal fields of lceland, Kenya, Ethiopia, etc. and subduction zones (Indonesia Japon, Indian and Chinese Himalayas, Chile, etc. . However, geothermal fields can also be found in intraplate zones in areas with a normal heat flow value (e. g. , Paris basin or slightly higher (e. g. Hungarian basin. Generally these fields produce a low-enthalpy fluid that can be used for non-electric exploitation. The best-known geothermal systems, and the only ones exploited so far, belong to the 'hydrothermal convective' type. These occur wherever a fluid circulation, mainly of meteoric origin, is able to develop in sufficiently permeable rocks near a heat source (such as a magmatic intrusion or at depths at which it can be heated by the normal geothermal gradian. This type of system is usually divided intowater-dominatedsystems, where the continuous fluid phase in the reservoir is liquid andvapour dominatedsystems where steam is the continuous phase. Other geothermal systems have still to be utilized and probably will be exploited as progress is made in technology. These are: a geopressured systems, found in some subsident sedimentary basins containing high-temperature connate waters of near lithostatic pressure; b the so-called 'hot dry rocks', which can be used ta create artificial systems by artificial fracturing of the high-temperature rocks and induced circulation of closed-circuit fluids. Geothermal energy is exploited: a To generate electricity. The total installed geothermoelectric capacity throughout the

  17. Direct uranium isotope ratio analysis of single micrometer-sized glass particles

    Science.gov (United States)

    Kappel, Stefanie; Boulyga, Sergei F.; Prohaska, Thomas

    2012-01-01

    We present the application of nanosecond laser ablation (LA) coupled to a ‘Nu Plasma HR’ multi collector inductively coupled plasma mass spectrometer (MC-ICP-MS) for the direct analysis of U isotope ratios in single, 10–20 μm-sized, U-doped glass particles. Method development included studies with respect to (1) external correction of the measured U isotope ratios in glass particles, (2) the applied laser ablation carrier gas (i.e. Ar versus He) and (3) the accurate determination of lower abundant 236U/238U isotope ratios (i.e. 10−5). In addition, a data processing procedure was developed for evaluation of transient signals, which is of potential use for routine application of the developed method. We demonstrate that the developed method is reliable and well suited for determining U isotope ratios of individual particles. Analyses of twenty-eight S1 glass particles, measured under optimized conditions, yielded average biases of less than 0.6% from the certified values for 234U/238U and 235U/238U ratios. Experimental results obtained for 236U/238U isotope ratios deviated by less than −2.5% from the certified values. Expanded relative total combined standard uncertainties Uc (k = 2) of 2.6%, 1.4% and 5.8% were calculated for 234U/238U, 235U/238U and 236U/238U, respectively. PMID:22595724

  18. The alpha-recoil effects of uranium in the Oklo reactor

    Science.gov (United States)

    Sheng, Z. Z.; Kuroda, P. K.

    1984-12-01

    A series of acid-leaching experiments have been carried out on a sample of uranium ore from reactor zone number 10 of the Oklo mines in Gabon. Anomalously high U-234/U-238 ratios were observed accompanied by modestly increased U-235/U-238 ratios in uranium fractions. These results, which can be interpreted as being due to the alpha-recoil effects of U-238 and Pu-239, provide a convenient way of calculating the conversion factor (the fraction of uranium atoms converted to plutonium) of the natural reactors from radiochemical data, obviating the necessity for mass-spectrometric measurements.

  19. Power level effects on thorium-based fuels in pressure-tube heavy water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bromley, B.P.; Edwards, G.W.R., E-mail: blair.bromley@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Sambavalingam, P. [Univ. of Ontario Inst. of Technology, Oshawa, Ontario (Canada)

    2016-06-15

    Lattice and core physics modeling and calculations have been performed to quantify the impact of power/flux levels on the reactivity and achievable burnup for 35-element fuel bundles made with Pu/Th or U-233/Th. The fissile content in these bundles has been adjusted to produce on the order of 20 MWd/kg burnup in homogeneous cores in a 700 MWe-class pressure-tube heavy water reactor, operating on a once-through thorium cycle. Results demonstrate that the impact of the power/flux level is modest for Pu/Th fuels but significant for U-233/Th fuels. In particular, high power/flux reduces the breeding and burnup potential of U-233/Th fuels. Thus, there may be an incentive to operate reactors with U-233/Th fuels at a lower power density or to develop alternative refueling schemes that will lower the time-average specific power, thereby increasing burnup.(author)

  20. Determination of Reportable Radionuclides for DWPF Sludge Batch 3 (Macrobatch 4)

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C

    2005-05-01

    The Waste Acceptance Product Specifications (WAPS) 1.2 require that ''The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115''. As part of the strategy to meet WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production through the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, IAEA Safeguards Reporting for HLW, requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The Defense Waste Processing Facility (DWPF) is receiving radioactive sludge slurry from High Level Waste Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the previous contents of Tank 40 (Sludge Batch 2) and the sludge that was transferred to Tank 40 from Tank 51. The blend of sludge from Tank 51 and Tank 40 defines Macrobatch 4 (also referred to as Sludge Batch 3). This report develops the list of reportable radionuclides and associated activities and determines the radionuclide activities as a function of time. The DWPF will use this list and the activities as one of

  1. REPORTABLE RADIONUCLIDES IN DWPF SLUDGE BATCH 7A (MACROBATCH 8)

    Energy Technology Data Exchange (ETDEWEB)

    Reboul, S.; Diprete, D.; Click, D.; Bannochie, C.

    2011-12-20

    The Waste Acceptance Product Specifications (WAPS) 1.2 require that the waste producer 'shall report the curie inventory of radionuclides that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115.' As part of the strategy to meet WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type all radionuclides that have half-lives longer than 10 years and contribute greater than 0.01 percent of the total curie inventory from the time of production through the 1100 year period from 2015 through 3115. The initial list of radionuclides to be reported is based on the design-basis glass identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report. However, it is required that the list be expanded if other radionuclides with half-lives greater than 10 years are identified that meet the 'greater than 0.01% of the curie inventory' criterion. Specification 1.6 of the WAPS, International Atomic Energy Agency Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, and U-238; and Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. Therefore, the complete list of reportable radionuclides must also include these sets of U and Pu isotopes - and the U and Pu isotopic mass distributions must be identified. The DWPF receives HLW sludge slurry from Savannah River Site (SRS) Tank 40. For Sludge Batch 7a (SB7a), the waste in Tank 40 contained a blend of the heel from Sludge Batch 6 (SB6) and the Sludge Batch 7 (SB7) material transferred to Tank 40 from Tank 51. This sludge blend is also referred to as Macrobatch 8. Laboratory analyses of a Tank 40 sludge sample were performed to quantify the concentrations of pertinent radionuclides in the SB7a waste. Subsequently

  2. Determination of uranium concentration and burn-up of irradiated reactor fuel in contaminated areas in Belarus using uranium isotopic ratios in soil samples

    OpenAIRE

    Mironov, V. P.; Matusevich, J. L.; Kudrjashov, V. P.; Ananich, P. I.; Zhuravkov, V. V.; Boulyga, S. F.; Becker, J. S.

    2005-01-01

    An analytical method is described for the estimation of uranium concentrations, of U-235/U-238 and U-236/U-238 isotope ratios and burn-up of irradiated reactor uranium in contaminated soil samples by inductively coupled plasma mass spectrometry. Experimental results obtained at 12 sampling sites situated on northern and western radioactive fallout tails 4 to 53 km distant from Chernobyl nuclear power plant (NPP) are presented. Concentrations of irradiated uranium in the upper 0-10cm soil laye...

  3. Magnetic mirror fusion-fission early history and applicability to other systems

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R

    2009-08-24

    these wastes in specially designed fission machines. Fusion can produce U-233 along with over 2.4%U-232 making the material largely nonproliferating and this material can in effect add neutrons to a fission reactor that would otherwise be short of reactivity to burn wastes. Similar ideas apply to Pu production. Unlike enrichment, producing U-233 does not burden the system with lots of U-238 with its source of more actinide wastes. The idea is fission plants are already designed and proven to fission at impressive power density and safety whereas fusion machines will have a harder time showing workability with thin walls separating the awkward geometry of the high curie inventory from the vacuum chamber that will get lots of radiation damage.

  4. Determination Of Reportable Radionuclides For DWPF Sludge Batch 7B (Macrobatch 9)

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. L.; DiPrete, D. P.

    2013-08-22

    The Waste Acceptance Product Specifications (WAPS) 1.2 require that “The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115”. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production through the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the heel from Sludge Batch 7a (SB7a) and Sludge Batch 7b (SB7b) that was transferred to Tank 40 from Tank 51. The blend of sludge in Tank 40 is also referred to as Macrobatch 9 (MB9). This report develops the list of reportable radionuclides and associated activities as a function of time. The DWPF will use this list and the activities as one of the inputs for the development of the Production Records that relate to

  5. DETERMINATION OF REPORTABLE RADIONUCLIDES FOR DWPF SLUDGE BATCH 6 (MACROBATCH 7)

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C.; Diprete, D.

    2011-06-01

    The Waste Acceptance Product Specifications (WAPS) 1.2 require that 'The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115'. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production through the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the heel from Sludge Batch 5 (SB5) with H-Canyon Np transfers completed after the start of processing SB5, and Sludge Batch 6 (SB6) that was transferred to Tank 40 from Tank 51. The blend of sludge in Tank 40 is also referred to as Macrobatch 7 (MB7). This report develops the list of reportable radionuclides and associated activities as a function of time. The DWPF will use this list and the activities as one of

  6. DETERMINATION OF REPORTABLE RADIONUCLIDES FOR DWPF SLUDGE BATCH 7B (MACROBATCH 9)

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. L.; Diprete, D. P.

    2014-05-01

    The Waste Acceptance Product Specifications (WAPS) 1.2 require that “The Producer shall report the inventory of radionuclides (in Curies) that have half-lives longer than 10 years and that are, or will be, present in concentrations greater than 0.05 percent of the total inventory for each waste type indexed to the years 2015 and 3115”. As part of the strategy to comply with WAPS 1.2, the Defense Waste Processing Facility (DWPF) will report for each waste type, all radionuclides (with half-lives greater than 10 years) that have concentrations greater than 0.01 percent of the total inventory from time of production through the 1100 year period from 2015 through 3115. The initial listing of radionuclides to be included is based on the design-basis glass as identified in the Waste Form Compliance Plan (WCP) and Waste Form Qualification Report (WQR). However, it is required that this list be expanded if other radionuclides with half-lives greater than 10 years are identified that may meet the greater than 0.01% criterion for Curie content. Specification 1.6 of the WAPS, International Atomic Energy Agency (IAEA) Safeguards Reporting for High Level Waste (HLW), requires that the ratio by weights of the following uranium and plutonium isotopes be reported: U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, and Pu- 242. Therefore, the complete set of reportable radionuclides must also include this set of U and Pu isotopes. The DWPF is receiving radioactive sludge slurry from HLW Tank 40. The radioactive sludge slurry in Tank 40 is a blend of the heel from Sludge Batch 7a (SB7a) and Sludge Batch 7b (SB7b) that was transferred to Tank 40 from Tank 51. The blend of sludge in Tank 40 is also referred to as Macrobatch 9 (MB9). This report develops the list of reportable radionuclides and associated activities as a function of time. The DWPF will use this list and the activities as one of the inputs for the development of the Production Records that relate to

  7. Fission Fragment Angular Distribution of 232Th(n,f) at the CERN n_TOF Facility

    CERN Document Server

    Tarrío, D; Audouin, L; Duran, I.; Paradela, C.; Tassan-Got, L; Altstadt, S; Andrzejewski, J; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Langer, C; Lederer, C; Leeb, H; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Massimi, C; Mastinu, P F; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Tagliente, G; Tain, J L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T J; Žugec, P

    2014-01-01

    The angular distribution of fragments emitted in neutron-induced fission of Th-232 was measured in the white spectrum neutron beam at the n\\_TOF facility at CERN. A reaction chamber based on Parallel Plate Avalanche Counters (PPAC) was used, where the detectors and the targets have been tilted 45 degrees with respect to the neutron beam direction in order to cover the full angular range of the fission fragments. A GEANT4 simulation has been developed to study the setup efficiency. The data analysis and the preliminary results obtained for the Th-232(n,f) between fission threshold and 100 MeV are presented here.

  8. In situ radiometric mapping as a proxy of sediment contamination : Assessment of the underlying geochemical and -physical principles

    NARCIS (Netherlands)

    van der Graaf, E. R.; Koomans, R. L.; Limburg, J.; de Vries, K.

    Correlations between sediment contaminants like heavy metals or organic micro-compounds and natural or anthropogenic radionuclides (K-40, (238)u, Th-232, (CS)-C-137) facilitates in situ mapping of the contaminated sediment using gamma-ray detectors. These maps can be male quickly and economically

  9. Reference material for radionuclides in sediment IAEA-384 (Fangataufa Lagoon sediment)

    DEFF Research Database (Denmark)

    Povinec, P.P.; Pham, M.K.; Sanchez-Cabeza, J.A.

    2007-01-01

    -238, Pu239+240 and Am-241). Information values are given for 12 radionuclides (Sr-90, Cs-137, Pb-210 (Po-210), Ra-226, Ra-228, Th-232, U-234, U-235, Pu-239, Pu-240 and Pu-241). Less reported radionuclides include Th-228, U-236, Np-239 and Pu-242. The reference material may be used for quality...

  10. GAMMA DETECTOR RESPONSE/SOIL CONCENTRATION CORRELATION STUDY AT THE AAR MANUFACTURING, INC. SITE, LIVONIA, MICHIGAN

    Energy Technology Data Exchange (ETDEWEB)

    ALTIC, NICK A

    2013-03-22

    At the NRC's request, ORAU conducted surveys of the AAR Manufacturing site during the period of September 25 through September 27, 2012. The survey activities included walkover surveys and sampling activities. Once the survey team was onsite, the NRC personnel decided to forgo survey activities in the New Addition and the pickling area. Areas of the planned study boundary were inaccessible due to overgrowth/large pieces of concrete covering the soil surface; therefore, the study boundary was redefined. Gamma walkover scans of the site boundary and front yard identified multiple areas of elevated gamma radiation. As a result, two judgmental samples were collected. Sample results were above thorium background levels The answer to the PSQ relating to the relationship between thorium concentration in soil and NaI instrument response is Yes. NaI instrument response can be used as a predictor of Th-232 concentration in the 0 to 1 m layer. An R2 value of 0.79 was determined for the surface soil relationship, thus satisfying the DQOs. Moreover, the regression was cross-checked by comparing the predicted Th-232 soil core concentration to the average Th-232 concentration (Section 5.3.2). Based on the cross-check, the regression equation provides a reasonable estimate for the Th-232 concentration at the judgmental locations. Consideration must be given when applying this equation to other soil areas of the site. If the contamination was heterogeneously distributed, and not distributed in a discrete layer as it was in the study area, then using the regression equation to predict Th-232 concentration would not be applicable.

  11. Use of uranium isotopes as a temporal and spatial tracer of nuclear contamination in the environment.

    Science.gov (United States)

    Tortorello, R; Widom, E; Renwick, W H

    2013-10-01

    The Fernald Feed Materials Production Center (FFMPC) was established in 1951 to process natural uranium (U) ore, enriched uranium (EU) and depleted uranium (DU). This study tests the utility of U isotopic ratios in sediment cores and lichens as indicators of the aerial extent, degree and timing of anthropogenic U contamination, using the FFMPC as a test case. An 80-cm-long sediment core was extracted from an impoundment located approximately 6.7 km southwest of the FFMPC. Elemental concentrations of thorium (2.7-6.2 μg g(-1)) and U (0.33-1.33 μg g(-1)) as well as major and minor U isotopes were analyzed in the core. The lack of measurable (137)Cs in the deepest sample as well as a natural (235)U/(238)U signature and no measurable (236)U, are consistent with pre-FFMPC activity. Anomalously elevated U with respect to Th concentrations occur in seven consecutive samples immediately above the base of the core (62-76 cm depth). Samples with elevated U concentrations also show variable (235)U/(238)U (0.00645-0.00748), and all contain measurable (236)U ((236)U/(238)U = 2.1 × 10(-6)-3.6 × 10(-5)). Correspondence between the known releases of U dust from the FFMPC through time and variations in sediment core U concentrations, (235)U/(238)U and (236)U/(238)U ratios provide evidence for distinct releases of both DU and EU. Furthermore, these relationships demonstrate that the sediment core serves as a robust archive of past environmental U contamination events. Samples in the upper 40 cm display natural (235)U/(238)U, but measurable (236)U/(238)U ((236)U/(238)U = 5.68 × 10(-6)-1.43 × 10(-5)), further indicating the continued presence of anthropogenic U in present-day sediment. Three local lichen samples were also analyzed, and all display either EU or DU signatures coupled with elevated (236)U/(238)U, recording airborne U contamination from the FFMPC. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Contribution to the study of {sup 233}U production with MOX-ThPu fuel in PWR reactor. Transition scenarios towards Th/{sup 233}U iso-generating concepts in thermal spectrum. Development of the MURE fuel evolution code; Contribution a l'etude de la production d'{sup 233}U en combustible MOX-ThPu en reacteur a eau sous pression. Scenarios de transition vers des concepts isogenerateurs Th/{sup 233}U en spectre thermique. Developpement du code MURE d'evolution du combustible

    Energy Technology Data Exchange (ETDEWEB)

    Michel-Sendis, F

    2006-12-15

    If nuclear power is to provide a significant fraction of the growing world energy demand, only through the breeding concept can the development of sustainable nuclear energy become a reality. The study of such a transition, from present-day nuclear technologies to future breeding concepts is therefore pertinent. Among these future concepts, those using the thorium cycle Th/U-233 in a thermal neutron spectrum are of particular interest; molten-salt type thermal reactors would allow for breeding while requiring comparatively low initial inventories of U-233. The upstream production of U-233 can be obtained through the use of thorium-plutonium mixed oxide fuel in present-day light water reactors. This work presents, firstly, the development of the MURE evolution code system, a C++ object-oriented code that allows the study, through Monte Carlo (M.C.) simulation, of nuclear reactors and the evolution of their fuel under neutron irradiation. The M.C. methods are well-suited for the study of any reactor, whether it'd be an existing reactor using a new kind of fuel or a future concept altogether, the simulation is only dependent on nuclear data. Exact and complex geometries can be simulated and continuous energy particle transport is performed. MURE is an interface with MCNP, the well-known and validated transport code, that allows, among other functionalities, to simulate constant power and constant reactivity evolutions. Secondly, the study of MOX ThPu fuel in a conventional light water reactor (REP) is presented; it explores different plutonium concentrations and isotopic qualities in order to evaluate their safety characteristics. Simulation of their evolution allows us to quantify the production of U-233 at the end of burnup. Last, different french scenarios validating a possible transition towards a park of thermal Th/U-233 breeders, are presented. In these scenarios, U-233 is produced in ThPu moxed light water reactors. (author)

  13. Neutronics of a mixed-flow gas-core reactor

    Energy Technology Data Exchange (ETDEWEB)

    Soran, P.D.; Hansen, G.E.

    1977-11-01

    The study was made to investigate the neutronic feasibility of a mixed-flow gas-core reactor. Three reactor concepts were studied: four- and seven-cell radial reactors and a seven-cell scallop reactor. The reactors were fueled with UF/sub 6/ (either U-233 or U-235) and various parameters were varied. A four-cell reactor is not practical nor is the U-235 fueled seven-cell radial reactor; however, the 7-cell U-233 radial and scallop reactors can satisfy all design criteria. The mixed flow gas core reactor is a very attractive reactor concept and warrants further investigation.

  14. Special Analysis for the Disposal of the Consolidated Edison Uranium Solidification Project Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Management

    2013-01-31

    The purpose of this Special Analysis (SA) is to determine if the Oak Ridge (OR) Consolidated Edison Uranium Solidification Project (CEUSP) uranium-233 (233U) waste stream (DRTK000000050, Revision 0) is acceptable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). The CEUSP 233U waste stream requires a special analysis because the concentrations of thorium-229 (229Th), 230Th, 232U, 233U, and 234U exceeded their NNSS Waste Acceptance Criteria action levels. The acceptability of the waste stream is evaluated by determining if performance assessment (PA) modeling provides a reasonable expectation that SLB disposal is protective of human health and the environment. The CEUSP 233U waste stream is a long-lived waste with unique radiological hazards. The SA evaluates the long-term acceptability of the CEUSP 233U waste stream for near-surface disposal as a two tier process. The first tier, which is the usual SA process, uses the approved probabilistic PA model to determine if there is a reasonable expectation that disposal of the CEUSP 233U waste stream can meet the performance objectives of U.S. Department of Energy Manual DOE M 435.1-1, “Radioactive Waste Management,” for a period of 1,000 years (y) after closure. The second tier addresses the acceptability of the OR CEUSP 233U waste stream for near-surface disposal by evaluating long-term site stability and security, by performing extended (i.e., 10,000 and 60,000 y) modeling analyses, and by evaluating the effect of containers and the depth of burial on performance. Tier I results indicate that there is a reasonable expectation of compliance with all performance objectives if the OR CEUSP 233U waste stream is disposed in the Area 5 RWMS SLB disposal units. The maximum mean and 95th percentile PA results are all less than the performance objective for 1,000 y. Monte Carlo uncertainty analysis indicates that there is a high likelihood of

  15. Model of the long-term transfer of radionuclides in forests

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Rodolfo [Facilia AB, Bromma (Sweden)

    2006-05-15

    This report describes a model of the long-term behaviour in temperate and boreal forests of radionuclides entering the ecosystem with subsurface water. The model can be applied for most radionuclides that are of relevance in safety assessment of repositories for high-level radioactive waste. The model can be used for estimating radionuclide concentrations in soil, trees, understorey plants, mushrooms and forest mammals. A recommended (nominal) value and an interval of variation are provided for each model parameter and a classification of parameters by the degree of confidence in the values is given. Model testing against existing empirical data showing satisfactory results is also presented. Forests can play an important role in the spatial and temporal distribution of radionuclides in the environment. Despite of this, forest ecosystems have not been addressed in previous safety assessments. This can be explained by the fact that a suitable model of the long-term transfer of a wide range of radionuclides in forests has not been readily available. The objective of this work was to develop a forest model applicable for a wide range of radionuclides of relevance for high level radioactive waste management (Am-241, Cl-36, Cs-135, I-129, Ni-59, Np-237, Pu-239, Ra-226, Sr-90, Tc-99, Th-232, U-238) that can potentially enter the ecosystem with contaminated groundwater. The model assumes that biomass growth, precipitation and evapo-transpiration drive the radionuclide cycling in the system by influencing the uptake of radionuclides by vegetation and their export from the system via runoff. The mathematical model of radionuclide transfer consists of a system of ordinary differential describing the mass balance in different forest compartments, taking into account the fluxes in and out from the compartment and the radionuclides decay. The fluxes between compartments are calculated by multiplying a transfer coefficient (TC) by the radionuclide inventory in the compartment

  16. Occurrence of selected radionuclides in ground water used for drinking water in the United States; a reconnaissance survey, 1998

    Science.gov (United States)

    Focazio, Michael J.; Szabo, Zoltan; Kraemer, Thomas F.; Mullin, Ann H.; Barringer, Thomas H.; dePaul, Vincent T.

    2001-01-01

    concentration of 72.3 pCi/L measured in water from a non-transient, noncommunity, public-supply well in Maryland.Radium-224, which is a decay product of Ra-228 in the Th-232 decay series, was significantly correlated with Ra-228 (Spearman?s rank correlation coefficient ?r? equals 0.82) and to a lesser degree with Ra-226 (r equals 0.69), which is an isotope in the U-238 decay series. The rank correlation coefficient between Ra-226 and Ra-228 was 0.63. The high correlation between Ra-224 and Ra-228 concentrations and the corresponding isotopic ratios of the two (about 1:1 in 90 percent of the samples) indicates that the two radionuclides occur in approximately equal concentrations in most ground water sampled. Thus, Ra-228 can be considered as a reasonable proxy indicator for the occurrence of Ra-224 in ground water.The maximum concentration of Po-210 was 4.85 pCi/L and exceeded 1 pCi/L in only two samples. The maximum concentration of Pb-210 was 4.14 pCi/L, and about 10 percent of the samples exceeded 1 pCi/L. Areas with known, or suspected, elevated concentrations of polonium and lead were not targeted in this survey.Three major implications are drawn for future radionuclide monitoring on the basis of this information: (1) grossalpha particle analyses of ground water should be done within about 48?72 hours after collection to determine the presence of the short-lived, alpha-particle emitting isotopes, such as Ra-224, which was detected in elevated concentrations in many of the samples collected for this survey; (2) the isotope ratios of Ra-224 to Ra-228 in ground water are variable on a national scale, but the two radioisotopes generally occur in ratios near 1:1, therefore, the more commonly measured Ra-228 can be used as an indicator of Ra-224 occurrence for some general purposes other than compliance; and (3) the isotopic ratios of Ra-226 to Ra-228 were less than 3:2 in many samples. These ratios corroborate results of previous studies that have shown the presence of Ra-228

  17. Improving the accuracy and precision of TIMS U-series ages of modern corals from the Great Barrier Reef, Australia

    Science.gov (United States)

    Clark, Tara; Zhao, Jian-Xin; Feng, Yuexing; Done, Terry; Jupiter, Stacy; Lough, Janice; Matson, Eric; Pandolfi, John; Roff, George

    2010-05-01

    The main limiting factor in obtaining precise and accurate Uranium-series ages of modern corals (e.g. since European settlement of northern Australia around 1850 AD), is the ability to constrain and correct for initial or non-radiogenic 230Th. This is becoming particularly important in paleoecological research where accurate chronologies are required to pinpoint changes in community structure and the timing of mortality events in order to identify possible drivers. In this study, thermal ionisation mass spectrometry (TIMS) Uranium-series dating of 61 samples collected from living and non-living Porites spp. from the near shore region of the GBR was performed to spatially constrain initial 230Th/232Th (230Th/232Th0) variability. In the living Porites corals, the majority of 230Th/232Th0 values were higher than the bulk-Earth value (~4.4×10-6) generally assumed for non-radiogenic 230Th corrections where the primary source of initial thorium is terrestrially derived. Despite samples being taken from regions adjacent to contrasting levels of land modification, no apparent difference was found in 230Th/232Th0 between regions exposed to varying levels of sedimentation during runoff events. However, 230Th/232Th0 variability is evident between reefs within each region. Overall, most samples across the entire region give 230Th/232Th0 values in the range of 6±1×10-6. An examination of 232Th/238U versus 230Th/238U from living and non-living corals revealed mainly two components contributing to initial 230Th in the non-living coral samples. High 232Th concentrations found in the majority of non-living coral samples suggest that a significant amount of Th may have been incorporated into the coral skeleton through post-mortem non-carbonate sediment infiltration. The results of this study demonstrate that accurate U-series ages cannot be achieved where single non-radiogenic thorium correction values are used interchangeably for samples taken from different hydrological

  18. Effect of ultra high temperature ceramics as fuel cladding materials on the nuclear reactor performance by SERPENT Monte Carlo code

    Energy Technology Data Exchange (ETDEWEB)

    Korkut, Turgay; Kara, Ayhan; Korkut, Hatun [Sinop Univ. (Turkey). Dept. of Nuclear Energy Engineering

    2016-12-15

    Ultra High Temperature Ceramics (UHTCs) have low density and high melting point. So they are useful materials in the nuclear industry especially reactor core design. Three UHTCs (silicon carbide, vanadium carbide, and zirconium carbide) were evaluated as the nuclear fuel cladding materials. The SERPENT Monte Carlo code was used to model CANDU, PWR, and VVER type reactor core and to calculate burnup parameters. Some changes were observed at the same burnup and neutronic parameters (keff, neutron flux, absorption rate, and fission rate, depletion of U-238, U-238, Xe-135, Sm-149) with the use of these UHTCs. Results were compared to conventional cladding material zircalloy.

  19. Independent Verification Final Summary Report for the David Witherspoon, Inc. 1630 Site Knoxville, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    P.C. Weaver

    2009-04-29

    The primary objective of the independent verification was to determine if BJC performed the appropriate actions to meet the specified “hot spot” cleanup criteria of 500 picocuries per gram (pCi/g) uranium-238 (U-238) in surface soil. Specific tasks performed by the independent verification team (IVT) to satisfy this objective included: 1) performing radiological walkover surveys, and 2) collecting soil samples for independent analyses. The independent verification (IV) efforts were designed to evaluate radioactive contaminants (specifically U-238) in the exposed surfaces below one foot of the original site grade, given that the top one foot layer of soil on the site was removed in its entirety.

  20. CTC Sentinel. Volume 7, Issue 7

    Science.gov (United States)

    2014-07-01

    thorium was used with plutonium -U-233 devices tested in 1955.15 The yield of the detonation was less than anticipated.16 The process of transmuting...instructor teaching in the Chemistry and Life Science Department at the U.S. Military Academy, West Point. CPT Hummel previously served in both Iraq and

  1. A small, 1400 deg Kelvin, reactor for Brayton space power systems

    Science.gov (United States)

    Lantz, E.; Mayo, W.

    1972-01-01

    A preliminary cost estimate for a small reactor in Brayton space power systems with (u-233)n or (pu-239)n as the fuel in the T-111 fuel elements totaled to about four million dollars; considered is a 22.8 in. diameter reactor with 247 fuel elements.

  2. 10 CFR 110.21 - General license for the export of special nuclear material.

    Science.gov (United States)

    2010-01-01

    ..., U-233 or U-235, or 10 kilograms of 1 percent enriched uranium), not to exceed 0.1 effective kilogram... the following to any country not listed in § 110.28: (1) Low-enriched uranium as residual... and Pu-238, in sensing components in instruments, if no more than 3 grams of enriched uranium or 0.1...

  3. 10 CFR 110.41 - Executive Branch review.

    Science.gov (United States)

    2010-01-01

    ... source material or low-enriched uranium to EURATOM and Japan for enrichment up to 5 percent in the isotope uranium-235, and those categories of exports approved in advance by the Executive Branch as... facility. (2) More than one effective kilogram of high-enriched uranium or 10 grams of plutonium or U-233...

  4. 10 CFR 73.60 - Additional requirements for physical protection at nonpower reactors.

    Science.gov (United States)

    2010-01-01

    ... licensee uranium-235 (contained in uranium enriched to 20 percent or more in the U-235 isotope), uranium... manufacturing process, contained in 30-gallon or larger containers, with a uranium-235 content of less than 0.25... formula, grams=(grams contained U-235)+2.5 (grams U-233+grams plutonium), shall protect the special...

  5. 10 CFR 110.40 - Commission review.

    Science.gov (United States)

    2010-01-01

    ... plutonium, except for exports of source material or low-enriched uranium to EURATOM or Japan for enrichment up to 5 percent in the isotope uranium-235, and those categories of exports which the Commission has... kilogram of high-enriched uranium, plutonium or U-233. (3) Nuclear grade graphite for nuclear end use. (4...

  6. Low lying states of Th229

    DEFF Research Database (Denmark)

    Andersen, Torkild; Maack Bisgård, K.; Hansen, P.Gregers

    1961-01-01

    The decay of 1.6 × 105y U233 has been studied by means of a six gap beta-ray spectrometer, a xenon filled proportional counter and scintillation spectrometers. Internal conversion electrons having energies below 100 keV were measured. The mixing ratios for the 42 keV and the 55 keV transitions ag...

  7. Hyperdeformation and clusterization in the actinide region

    NARCIS (Netherlands)

    Krasznahorkay, A; Habs, D; Hunyadi, M; Gassmann, D; Csatlos, M; Eisermann, Y; Faestermann, T; Graw, G; Gulyas, J; Hertenberger, R; Maier, HJ; Mate, Z; Metz, A; Ott, J; Thirolf, PG; van der Werf, SY

    2001-01-01

    The U-233(d,pf)U-234, and the U-235(d,pf)U-236 reactions have been studied with high energy resolution. The observed fission resonances were described as members of rotational bands with rotational parameters characteristic of hyperdeformed nuclear shapes. Information on the K values of the bands

  8. Development of a “Fission-proxy” Method for the Measurement of 14-MeV Neutron Fission Yields at CAMS

    Energy Technology Data Exchange (ETDEWEB)

    Gharibyan, Narek [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-25

    Relative fission yield measurements were made for 50 fission products from 25.6±0.5 MeV alpha-induced fission of Th-232. Quantitative comparison of these experimentally measured fission yields with the evaluated fission yields from 14-MeV neutron-induced fission of U-235 demonstrates the feasibility of the proposed fission-proxy method. This new technique, based on the Bohr-independence hypothesis, permits the measurement of fission yields from an alternate reaction pathway (Th-232 + 25.6 MeV α → U-236* vs. U-235 + 14-MeV n → U-236*) given that the fission process associated with the same compound nucleus is independent of its formation. Other suitable systems that can potentially be investigated in this manner include (but are not limited to) Pu-239 and U-237.

  9. The natural radioactivity contents in feed coals from the lignite-fired power plants in Western Anatolia, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Cam, N.F.; Yaprak, G.; Eren, E. [Ege University, Izmir (Turkey). Faculty of Science

    2010-12-15

    Lignite burning is one of the sources of technologically enhanced exposure to humans from natural radionuclides. In the preliminary study, part of the survey, the activity concentrations of Ra-226, Th-232 and K-40 in 112 samples of feed lignites from seven lignite-fired power plants in Western Anatolia (Seyitomer, Tuncbilek, Orhaneli, Soma, Yatagan, Yenikoy and Kemerkoy) were, therefore, determined by scintillation gamma spectrometry. The ranges of the relevant radionuclides in the lignite samples are as follows: Ra-226, 23-291 Bq kg{sup -1}; Th-232, 12-68 Bq kg{sup -1}; and K-40, 67-284 Bq kg{sup -1}. Taking the coefficient of variation (CV) as a measure of the variability, the CV is also calculated for the natural radionuclides in the feed lignites. Furthermore, the dose rates in the coal-handling areas due to external gamma radiation are found to be within the range specified by UNSCEAR (2000) report.

  10. Thorium-232 fission induced by light charged particles up to 70 MeV

    Science.gov (United States)

    Métivier, Vincent; Duchemin, Charlotte; Guertin, Arnaud; Michel, Nathalie; Haddad, Férid

    2017-09-01

    Studies have been devoted to the production of alpha emitters for medical application in collaboration with the GIP ARRONAX that possesses a high energy and high intensity multi-particle cyclotron. The productions of Ra-223, Ac-225 and U-230 have been investigated from the Th-232(p,x) and Th-232(d,x) reactions using the stacked-foils method and gamma spectrometry measurements. These reactions have led to the production of several fission products, including some with a medical interest like Mo-99, Cd-115g and I-131. This article presents cross section data of fission products obtained from these undedicated experiments. These data have been also compared with the TALYS code results.

  11. DHS Summary Report -- Robert Weldon

    Energy Technology Data Exchange (ETDEWEB)

    Weldon, Robert A. [Los Alamos National Laboratory

    2012-07-31

    fission multiplicity was included to provide a separate capability for computing multiplicity as well as including several new features not already included in MCNPX. These new features include: (1) prompt gamma emission/multiplicity from neutron-induced fission; (2) neutron multiplicity and gamma emission/multiplicity from photofission; and (3) an option to enforce energy correlation for gamma neutron multiplicity emission. These new capabilities allow correlated signal detection for identifying presence of special nuclear material (SNM). Therefore, these new capabilities help meet the missions of the Domestic Nuclear Detection Office (DNDO), which is tasked with developing nuclear detection strategies for identifying potential radiological and nuclear threats, by providing new simulation capability for detection strategies that leverage the new available physics in the LLNL multiplicity capability. Two types of tests were accomplished this summer to test the default LLNL neutron multiplicity capability: neutron-induced fission tests and spontaneous fission tests. Both cases set the 6th entry on the PHYS:N card to 5 (i.e. use LLNL multiplicity). The neutron-induced fission tests utilized a simple 0.001 cm radius sphere where 0.0253 eV neutrons were released at the sphere center. Neutrons were forced to immediately collide in the sphere and release all progeny from the sphere, without further collision, using the LCA card, LCA 7j -2 (therefore density and size of the sphere were irrelevant). Enough particles were run to ensure that the average error of any specific multiplicity did not exceed 0.36%. Neutron-induced fission multiplicities were computed for U-233, U-235, Pu-239, and Pu-241. The spontaneous fission tests also used the same spherical geometry, except: (1) the LCA card was removed; (2) the density of the sphere was set to 0.001 g/cm3; and (3) instead of emitting a thermal neutron, the PAR keyword was set to PAR=SF. The purpose of the small density was to

  12. Superasymmetric fission at intermediate energy and production of neutron-rich nuclei with A

    NARCIS (Netherlands)

    Huhta, M; Dendooven, P; Honkanen, A; Jokinen, A; Lhersonneau, G; Oinonen, M; Penttila, H; Perajarvi, K; Rubchenya, VA; Aysto, J

    1997-01-01

    The yields of neutron-rich Ni, Cu, Zn, Ga and Ge-isotopes were measured in 25 MeV proton induced fission of U-238 using the ion guide-based isotope separator technique. The results indicate enhancement for superasymmetric mass division at intermediate excitation energy of the fissioning nucleus and

  13. The precise measurements of integral (over spectrum of Cf-252) total neutron cross-sections and transmission coefficients for the testing of differential total cross-section

    Energy Technology Data Exchange (ETDEWEB)

    Guzhovskii, B.Ya.; Grebennikov, A.N.; Gorelov, V.P.; Farafontov, G.G.; Rudnev, V.S. [Russian Federal Nuclear Center, Arzamas (Russian Federation)

    1994-12-31

    The integral total cross-sections of nuclei Be, C, Al, Fe, Ni, Cu, Nb, Mo, Ta, W and U-238 were measured on Cf-252 spontaneous fission neutron spectrum and compared by calculated values from various libraries of evaluated neutron data.

  14. Reference material for radionuclides in sediment IAEA-384 (Fangataufa Lagoon sediment)

    NARCIS (Netherlands)

    Povinec, P.P.; Pham, M.K.; Sanchez-Cabeza, J.A.; Barci-Funel, G.; Bojanowski, R.; Boshkova, T.; Burnett, W.C.; Carvalho, F.; Chapeyron, B.; Cunha, I.L.; Dahlgaard, H.; Galabov, N.; FiField, L.K.; Gastaud, J.; Geering, J.J.; Gomez, I.F.; Green, N.; Hamilton, T.; Ibanez, F.L.; Ibn Majah, M.; John, M.; Kanisch, G.; Kenna, T.C.; Kloster, M.; Korun, M.; Liong Wee Kwong, L.; Rosa, la J.; Lee, S.H.; Levy-Palomo, I.; Malatova, M.; Maruo, Y.; Mitchell, P.; Murciano, I.V.; Nelson, R.; Nouredine, A.; Oh, J.S.; Origioni, B.; Petit, le G.; Petterson, H.B.L.; Reineking, A.; Smedley, P.A.; Suckow, A.; Struijs, van der T.D.B.; Voors, P.I.; Yoshimizu, K.; Wyse, E.

    2007-01-01

    A reference material designed for the determination of anthropogenic and natural radionuclides in sediment, IAEA-384 (Fangataufa Lagoon sediment), is described and the results of certification are presented. The material has been certified for 8 radionuclides (40K, 60Co, 155Eu, 230Th, 238U, 238Pu,

  15. First spatial separation of a heavy ion isomeric beam with amultiple-reflection time-of-flight mass spectrometer

    NARCIS (Netherlands)

    Dickel, T.; Plass, W. R.; Andres, S. Ayet San; Ebert, J.; Geissel, H.; Haettner, E.; Hornung, C.; Miskun, I.; Pietri, S.; Purushothaman, S.; Reiter, M. P.; Rink, A. -K.; Scheidenberger, C.; Weick, H.; Dendooven, P.; Diwisch, M.; Greiner, F.; Heisse, F.; Knoebel, R.; Lippert, W.; Moore, I. D.; Pohjalainen, I.; Prochazka, A.; Ranjan, M.; Takechi, M.; Winfield, J. S.; Xu, X.

    2015-01-01

    Po-211 ions in the ground and isomeric states were produced via U-238 projectile fragmentation at 1000 MeV/u. The Po-211 ions were spatially separated in flight from the primary beam and other reaction products by the fragment separator FRS. The ions were energy-bunched, slowed-down and thermalized

  16. First experimental results of a cryogenic stopping cell with short-lived, heavy uranium fragments produced at 1000 MeV/u

    NARCIS (Netherlands)

    Purushothaman, S.; Reiter, M. P.; Haettner, E.; Dendooven, P.; Dickel, T.; Geissel, H.; Ebert, J.; Jesch, C.; Plass, W. R.; Ranjan, M.; Weick, H.; Amjad, F.; Ayet, S.; Diwisch, M.; Estrade, A.; Farinon, F.; Greiner, F.; Kalantar-Nayestanaki, N.; Knoebel, R.; Kurcewicz, J.; Lang, J.; Moore, I. D.; Mukha, I.; Nociforo, C.; Petrick, M.; Pfuetzner, M.; Pietri, S.; Prochazka, A.; Rink, A. -K.; Rinta-Antila, S.; Scheidenberger, C.; Takechi, M.; Tanaka, Y. K.; Winfield, J. S.; Yavor, M. I.

    2013-01-01

    A cryogenic stopping cell (CSC) has been commissioned with U-238 projectile fragments produced at 1000 MeV/u. The spatial isotopic separation in flight was performed with the FRS applying a monoenergetic degrader. For the first time, a stopping cell was operated with exotic nuclei at cryogenic

  17. Formation and decay of hot nuclei in 475 MeV, 2 GeV proton- and 2 GeV He-3-induced reactions on Ag, Bi, An, and U

    NARCIS (Netherlands)

    Ledoux, [No Value; Bohlen, HG; Cugnon, J; Fuchs, H; Galin, J; Gatty, B; Gebauer, B; Guerreau, D; Hilscher, D; Jacquet, D; Jahnke, U; Josset, M; Leray, S; Lott, B; Morjean, M; Quednau, BM; Roschert, G; Rossner, H; Peghaire, A; Pienkowski, L; Siemssen, RH; Stephan, C

    The formation and decay of hot nuclei generated in the interaction of light projectiles (475 MeV and 2 GeV protons and 2 GeV He-3) on a series of targets (Ag-107, Au-197, Bi-209, and U-238) are studied with an apparatus combining the efficient detection of neutrons in 4 pi sr and an accurate

  18. 10 CFR Appendix B to Part 30 - Quantities 1 of Licensed Material Requiring Labeling

    Science.gov (United States)

    2010-01-01

    ... Uranium (natural) 2 100 Uranium-233 .01 Uranium-234—Uranium-235 .01 Vanadium-48 10 Xenon-131m 1,000 Xenon... alpha disintegration rate of U-238, U-234, and U-235. Note: For purposes of § 20.303, where there is...

  19. A simple method for determination of natural and depleted uranium in surface soil samples.

    Science.gov (United States)

    Vukanac, I; Novković, D; Kandić, A; Djurasević, M; Milosević, Z

    2010-01-01

    A simple and efficient method for determination of uranium content in surface soil samples contaminated with depleted uranium, by gamma ray spectrometry is presented. The content of natural uranium and depleted uranium, as well as the activity ratio (235)U/(238)U of depleted uranium, were determined in contaminated surface soil samples by application of this method. Copyright 2009 Elsevier Ltd. All rights reserved.

  20. Synthesis of uranyl acetylacetonate free of thorium 234

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Rendon, R.; Solache R, M.; Tenorio, D. (Instituto Nacional de Investigaciones Nucleares, Mexico City)

    1983-01-01

    A technique is described for synthesizing uranyl acetylacetonate free of thorium-234, and the method utilized in identifying it. The aim in the preparation of the thorium-234 free compound was to study the chemical effects produced by U-238 decay by means of detection only of the thorium-234 decay product.

  1. Uranium isotopes in the Greenland ice-sheet

    Science.gov (United States)

    Koide, M.; Goldberg, E. D.

    1983-11-01

    The U-234/U-238 activity ratio was measured in dated strata of the Dye-3 Greenland ice-sheet. Values were generally less than unity, indicating a source in weathered crustal rock debris. Three levels showed elevated ratios which are attributed to entry of debris from the aborted Russian satellite Cosmos 954 following residence in the stratosphere.

  2. Neutrons as Party Animals: An Analogy for Understanding Heavy-Element Fissility

    Science.gov (United States)

    Reed, B. Cameron

    2012-01-01

    I teach a general education class on the history of nuclear physics and the Manhattan Project. About halfway through the course we come to the discovery of fission and Niels Bohr's insight that it is the rare isotope of uranium, U-235, which fissions under slow-neutron bombardment as opposed to the much more common U-238 isotope. As an…

  3. Superdeformation, hyperdeformation and clustering in the actinide region

    NARCIS (Netherlands)

    Krasznahorkay, A; Habs, D; Hunyadi, M; Gassmann, D; Csatlos, M; Eisermann, Y; Faestermann, T; Graw, G; Gulyas, J; Hertenberger, R; Maier, HJ; Mate, Z; Metz, A; Ott, J; Thirolf, P; van der Werf, SY

    Excited states in the second minimum of Pu-240 were populated by the U-238(alpha, 2n) reaction at E-alpha=25 MeV. Conversion electrons from electromagnetic transitions preceding the fission of the 3.7 ns Pu-240f Shape isomer have been measured. In a combined analysis of e(-) and high resolution

  4. U-Sr isotopic speedometer: Fluid flow and chemical weatheringrates inaquifers

    Energy Technology Data Exchange (ETDEWEB)

    Maher, Kate; DePaolo, Donald J.; Christensen, John N.

    2005-12-27

    Both chemical weathering rates and fluid flow are difficultto measure in natural systems. However, these parameters are critical forunderstanding the hydrochemical evolution of aquifers, predicting thefate and transport of contaminants, and for water resources/water qualityconsiderations. 87Sr/86Sr and (234U/238U) activity ratios are sensitiveindicators of water-rock interaction, and thus provide a means ofquantifying both flow and reactivity. The 87Sr/86Sr values in groundwaters are controlled by the ratio of the dissolution rate to the flowrate. Similarly, the (234U/238U) ratio of natural ground waters is abalance between the flow rate and the dissolution of solids, andalpha-recoil loss of 234U from the solids. By coupling these two isotopesystems it is possible to constrain both the long-term (ca. 100's to1000's of years) flow rate and bulk dissolution rate along the flow path.Previous estimates of the ratio of the dissolution rate to theinfiltration flux from Sr isotopes (87Sr/86Sr) are combined with a modelfor (234U/238U) to constrain the infiltration flux and dissolution ratefor a 70-m deep vadose zone core from Hanford, Washington. The coupledmodel for both (234U/238U) ratios and the 87Sr/86Sr data suggests aninfiltration flux of 5+-2 mm/yr, and bulk silicate dissolution ratesbetween 10-15.7 and 10-16.5 mol/m2/s. The process of alpha-recoilenrichment, while primarily responsible for the observed variation in(234U/238U) of natural systems, is difficult to quantify. However, therate of this process in natural systems affects the interpretation ofmost U-series data. Models for quantifying the alpha-recoil loss fractionbased on geometric predictions, surface area constraints, and chemicalmethods are also presented. The agreement between the chemical andtheoretical methods, such as direct measurement of (234U/238U) of thesmall grain size fraction and geometric calculations for that sizefraction, is quite good.

  5. Fabrication of fuel rods containing /sup 233/U pelletized oxide fuels (LWBR Development Program)

    Energy Technology Data Exchange (ETDEWEB)

    Frankhouser, W.L.; Crain, H.H.; Fischer, R.L.; Suldan, J.H.; Eyler, J.H.; Speer, E.L.

    1967-02-01

    Approximately 13 kg of U-233 were fabricated into 1 wt % UO/sub 2/-ThO/sub 2/ and 26 wt % UO/sub 2/-ZrO/sub 2/ pellets and enclosed in Zircaloy-2 cladding tubes as 1299 blanket and 377 seed rods. The U-233 contained 38 ppM of U-232, and was purified as two batches of liquid UO/sub 2/(NO/sub 3/)/sub 2/ immediately prior to processing into powder form. All fuel rods were completed within 95 days of this initial solvent extraction of the nitrate. Overall U yield of nitrate to usable materials was over 90%, and only 14 rods were rejected in welding and all without loss of contained fuel. (NSA 21: 14872)

  6. Safety analysis of thorium-based fuels in the General Electric Standard BWR

    Energy Technology Data Exchange (ETDEWEB)

    Colby, M.J.; Townsend, D.B.; Kunz, C.L.

    1980-06-01

    A denatured (U-233/Th)O/sub 2/ fuel assembly has been designed which is energy equivalent to and hardware interchangeable with a modern boiling water reactor (BWR) reference reload assembly. Relative to the reference UO/sub 2/ fuel, the thorium fuel design shows better performance during normal and transient reactor operation for the BWR/6 product line and will meet or exceed current safety and licensing criteria. Power distributions are flattened and thermal operating margins are increased by reduced steam void reactivity coefficients caused by U-233. However, a (U-233/Th)O/sub 2/-fueled BWR will likely have reduced operating flexibility. A (U-235/Th)O/sub 2/-fueled BWR should perform similar to a UO/sub 2/-fueled BWR under all operating conditions. A (Pu/Th)O/sub 2/-fueled BWR may have reduced thermal margins and similar accident response and be less stable than a UO/sub 2/-fueled BWR. The assessment is based on comparisions of point model and infinite lattice predictions of various nuclear reactivity parameters, including void reactivity coefficients, Doppler reactivity coefficients, and control blade worths.

  7. Determination of uranium transfer factors from soils contaminated with natural uranium along the Vereinigten Mulde in Zwickau; Bestimmung von Transferfaktoren von Uran aus natuerlich belasteten Boeden entlang der Zwickauer und Vereinigten Mulde

    Energy Technology Data Exchange (ETDEWEB)

    Brand, Andreas

    2011-07-01

    According to IAEA the food chain soil-plants-human is the predominant radionuclide ingestion path. The consumption of contaminated vegetarian food causes a continuous radiation exposure. In this context the problem of contaminated meadows in the Zwickauer and Vereinigten Mulde that is used for agriculture is of predominant interest. In this area intensive uranium mining has caused severe environmental contamination. The agricultural crop land and the grass land were studied with respect to the radionuclides U-238 and U-234. Following the radiochemical separation using ion chromatography the samples were analyzed by alpha-spectrometry. Compared to non-contaminated areas significant specific activities were measured. The transfer factors of the radionuclides U-238 and U-234 were determined for different plant parts. The transfer factors decrease with increasing radioactive contamination of the soils.

  8. Calculation of 230Th U isochrons, ages, and errors

    Science.gov (United States)

    Ludwig, K. R.; Titterington, D.M.

    1994-01-01

    If analytical errors are responsible for the scatter of points on a 230Th-234U-238U isochron diagram, the isochron should be fitted by a technique that 1. (1) weights the points according to their analytical errors and error correlations, and 2. (2) either takes into account the presence of some of the same data in two coupled XY isochrons or (equivalently) uses a single, three-dimensional XYZ isochron. A method based on maximum-likelihood estimation is presented that fulfills these requirements, and the relevant equations for errors in age and initial 234U 238U are given. Equations for estimating the necessary isotope-ratio errors and error-correlations for both alpha-spectrometric and mass-spectrometric data are also developed. ?? 1994.

  9. BetaScint{trademark} fiber-optic sensor for detecting strontium-90 and uranium-238 in soil. Innovative technology summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    Accurate measurements of radioactivity in soils contaminated with Strontium-90 (Sr-90) or Uranium-238 (U-238) are essential for many DOE site remediation programs. These crucial measurements determine if excavation and soil removal is necessary, where remediation efforts should be focused, and/or if a site has reached closure. Measuring soil contamination by standard EPA laboratory methods typically takes a week (accelerated analytical test turnaround) or a month (standard analytical test turnaround). The time delay extends to operations involving heavy excavation equipment and associated personnel which are the main costs of remediation. This report describes an application of the BetaScint{trademark} fiber-optic sensor that measures Sr-90 or U-238 contamination in soil samples on site in about 20 minutes, at a much lower cost than time-consuming laboratory methods, to greatly facilitate remediation. This report describes the technology, its performance, its uses, cost, regulatory and policy issues, and lessons learned.

  10. Assessing depleted uranium (DU) contamination of soil, plants and earthworms at UK weapons testing sites.

    Science.gov (United States)

    Oliver, Ian W; Graham, Margaret C; MacKenzie, Angus B; Ellam, Robert M; Farmer, John G

    2007-07-01

    Depleted uranium (DU) weapons testing programmes have been conducted at two locations within the UK. An investigation was therefore carried out to assess the extent of any environmental contamination arising from these test programmes using both alpha spectrometry and mass spectrometry techniques. Uranium isotopic signatures indicative of DU contamination were observed in soil, plant and earthworm samples collected in the immediate vicinity of test firing points and targets, but contamination was found to be localised to these areas. This paper demonstrates the superiority of the (235)U : (238)U ratio over the (234)U : (238)U ratio for identifying and quantifying DU contamination in environmental samples, and also describes the respective circumstances under which alpha spectrometry or mass spectrometry may be the more appropriate analytical tool.

  11. Measuring Uranium Decay Rates for Advancement of Nuclear Forensics and Geochronology

    Energy Technology Data Exchange (ETDEWEB)

    Parsons-Davis, Tashi [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-31

    Radioisotopic dating techniques are highly valuable tools for understanding the history of physical and chemical processes in materials related to planetary sciences and nuclear forensics, and rely on accurate knowledge of decay constants and their uncertainties. The decay constants of U-238 and U-235 are particularly important to Earth science, and often the measured values with lowest reported uncertainties are applied, although they have not been independently verified with similar precision. New direct measurements of the decay constants of U-238, Th-234, U-235, and U-234 were completed, using a range of analytical approaches. An overarching goal of the project was to ensure the quality of results, including metrological traceability to facilitate implementation across diverse disciplines. This report presents preliminary results of these experiments, as a few final measurements and calculations are still in progress.

  12. Uranium series dating of Allan Hills ice

    Science.gov (United States)

    Fireman, E. L.

    1986-01-01

    Uranium-238 decay series nuclides dissolved in Antarctic ice samples were measured in areas of both high and low concentrations of volcanic glass shards. Ice from the Allan Hills site (high shard content) had high Ra-226, Th-230 and U-234 activities but similarly low U-238 activities in comparison with Antarctic ice samples without shards. The Ra-226, Th-230 and U-234 excesses were found to be proportional to the shard content, while the U-238 decay series results were consistent with the assumption that alpha decay products recoiled into the ice from the shards. Through this method of uranium series dating, it was learned that the Allen Hills Cul de Sac ice is approximately 325,000 years old.

  13. Canyon transfer neutron absorber to fissile material ratio analysis. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Clemmons, J.S.

    1994-03-04

    Waste tank fissile material and non-fissile material estimates are used to evaluate criticality safety for the existing sludge inventory and batches of sludge sent to Extended Sludge Processing (ESP). This report documents the weight ratios of several non-fissile waste constituents to fissile waste constituents from canyon reprocessing waste streams. Weight ratios of Fe, Mn, Al, Mi, and U-238 to fissile material are calculated from monthly loss estimates from the F and H Canyon Low Heat Waste (LHW) and High Heat Waste (HHW) streams. The monthly weight ratios for Fe, Mn and U-238 are then compared to calculated minimum safe weight ratios. Documented minimum safe weight ratios for Al and Ni to fissile material are currently not available. Total mass data for the subject sludge constituents is provided along with scatter plots of the monthly weight ratios for each waste stream.

  14. Plutonium age dating (production date measurement) by inductively coupled plasma mass spectrometry

    OpenAIRE

    Varga, Zsolt; Nicholl, Adrian; Wallenius, Maria; Mayer, Klaus

    2015-01-01

    This paper describes rapid methods for the determination of the production date (age dating) of plutonium (Pu) materials by inductively coupled plasma mass spectrometry (ICP-MS) for nuclear forensic and safeguards purposes. One of the presented methods is a rapid, direct measurement without chemical separation using 235U/239Pu and 236U/240Pu chronometers. The other method comprises a straightforward extraction chromatographic separation, followed by ICP-MS measurement for the 234U/238Pu, 235U...

  15. Absolute measurement of rates of capture of neutrons in 238U and fission in 239Pu

    Science.gov (United States)

    Dulin, V. A.

    1981-04-01

    The absolute rate of capture of neutrons in U-238 was measured in terms of the Np-239 activity found (gamma radiation), using a calibrated Am-243 source to determine the efficiency of gamma recording in the detector. The absolute rate of fission of Pu-239 was determined by means of a fission chamber with a known number of Pu-239 nuclei, and the efficiency of fission fragment recording in the chamber was calculated.

  16. Basalt Petrogenesis Beneath Slow - and Ultraslow-Spreading Arctic Mid-Ocean Ridges

    Science.gov (United States)

    2009-02-01

    spectrometry (TIMS) at Los Alamos National Laboratory (LANL), New Mexico using methods described in Sims et al. (1999a; 1995) and Goldstein et al. (1989...isotopic compositions from Faure and Mensing (2005). The heavy black line shows a mixing trajectory between sample 1093 (the Kolbeinsey sample with...234U/238U) nearest to equilibrium) and seawater. U and Sr concentrations in seawater also from Faure and Mensing (2005). 60 Figure 5

  17. Basic characterization of highly enriched uranium by gamma spectrometry

    OpenAIRE

    Nguyen, Cong Tam; Zsigrai, Jozsef

    2005-01-01

    Gamma-spectrometric methods suitable for the characterization of highly enriched uranium samples encountered in illicit trafficking of nuclear materials are presented. In particular, procedures for determining the 234U, 235U, 238U, 232U and 236U contents and the age of highly enriched uranium are described. Consequently, the total uranium content and isotopic composition can be calculated. For determining the 238U and 232U contents a low background chamber was used. In addition, age dating of...

  18. Precise and accurate isotopic analysis of microscopic uranium-oxide grains using LA-MC-ICP-MS

    OpenAIRE

    Lloyd, Nicholas S.; Parrish, Randall R.; Horstwood, Matthew S.A.; Chenery, Simon R.N.

    2009-01-01

    Uranium isotope (235U, 236U, 238U) ratios were determined for microscopic uranium-oxide grains using laser-ablation multi-collector inductively-coupled-plasma mass-spectrometry (LA-MC-ICP-MS). The grains were retrieved from contaminated soil and dust samples. The analytical technique utilised is rapid, requires minimal sample preparation, and is well suited for nuclear forensic applications. Precision and accuracy were assessed by replicate analyses of natural uraninite grains: relative uncer...

  19. Measurement of the 238U Radiative Capture Cross Section with C6D6 at the CERN n_TOF Facility

    CERN Document Server

    Mingrone, F; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Berthoumieux, E; Billowes, J; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Cano-Ott, D; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Giubrone, G; Gonçalves, I F; González-Romero, E; Griesmayer, E; Guerrero, C; Gunsing, F; Hernández-Prieto, A; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Krtička, M; Kroll, J; Lampoudis, C; Langer, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L S; Losito, R; Mallick, A; Manousos, A; Marganiec, J; Martínez, T; Mastinu, P F; Mastromarco, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Robles, M S; Rubbia, C; Sabaté-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T; Žugec, P

    2014-01-01

    We present the preliminary results of the U-238(n,gamma) reaction cross section measurement, performed on April 2012 at the CERN n\\_TOF facility using C6D6 scintillation detectors over an energy range from thermal to 1 MeV. The goal of this measurement, which is part of a larger proposal, is to reach an uncertainty of 2\\% in the cross section. The experimental set-up and the methods used to obtain this result are described.

  20. A Review of Depleted Uranium Biological Effects: In Vitro Studies (Briefing charts)

    Science.gov (United States)

    2010-11-01

    U-238 What is “Depleted Uranium” Enrichment process Reduced U234, no daughter products, radium , radon DU is Radioactive: Alpha Particle Emitter... Isotopes (natural and depleted) * Specific DU Natural Uranium Activity SA by WT% Isotope ( Ci/g) ( Ci/g) ( Ci/g) Total...2007. 1. Radiation-specific Damage - Dicentric Chromosomes Uranium Isotopes : Rad Activity Chem Tox DU 0.43 1.0 238U 0.33 1.0 Does DU Cause Radiation

  1. Monitoring for thorium intakes by means of thoron (RN-220) in breath measurement; Inkorporationsueberwachung auf Thorium mittels RN-220-Exhalationsanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Eisenmenger, A.; Riedel, W. [Freie Univ. Berlin (Germany). Universitaetsklinikum Benjamin Franklin; Brose, J.; Scheler, R. [Bundesamt fuer Strahlenschutz, Berlin (Germany)

    1998-12-31

    Thoron (Rn-220) in Breath Measurement is a sensitive method for routine monitoring of inhaled thorium intakes. Decay products of exhaled thoron (Po-216 and Pb-212), emanating from Thorium body burdens, are collected electrostatically and their progeny (esp. Po-212) are measured subsequently by alpha-spectrometry. The method has been optimized in respect to chamber volume, collection head geometry and position, supplied high voltage, breathing rate, humidity and counting time. Actually the method is capable to detect Th-228 in the lungs at a level as high as 3% of an Annual Limit on Intake, corresponding to 6 Bq of inhaled Th-228 (class W), as required by the German radiation protection monitoring guidelines. First measurements at occupationally exposed subjects in germany showed burdens up to 7,4 Bq Thorium in lungs derived from an exhalation rate of 3,7%. The amount of Th-232 results from the ratio of Th-228/Th-232 of the handeled material. Corresponding urine excretion analysis showed similar results. With in-vivo measurements no result above detection limit was found at all. (orig.) [Deutsch] Rn-220 Exhalationsmessungen sind eine sensible Methode zur Routineueberwachung von (inhalativen) Thoriuminkorporationen. Zerfallsprodukte des aus Thoriumkoerperdepots abgeatmeten Rn-220 (Po-216 und Pb-212) werden elektrostatisch gesammelt und deren Folgeprodukte dann alpha-spektrometrisch gemessen (spez. Po-212). Die Methode wurde in bezug auf das Sammelkammervolumen, die Sammelkopfgeometrie und -position, die angelegte Hochspannung, die Atemrate, die Atemfeuchtigkeit und die Messzeit optimiert. Derzeit ist es moeglich, mit dieser Methode 3% einer Jahresaktivitaetszufuhr ueber Inhalation in Bezug auf Th-228, entsprechend 6 Bq (Klasse W), nachzuweisen. Erste Messungen an beruflich Exponierten der Thorium-verarbeitenden Industrie in Deutschland zeigten Ergebnisse von bis 7,4 Bq Th-228 Lungendepots bei einer zugrunde gelegten Abatemrate von 3.7%. Der Th-232 Anteil ergibt sich

  2. Distribution of Th-230 and Th-228 in foods(II)

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hee Dong; Kim, Wan; Lim, S. K.; Lee, S. A.; Choi, M. S.; Zheng, Y. C. [Kyungpook National Univ., Daegu (Korea, Republic of); Kim, Do Sung [Daegu Univ., Daegu (Korea, Republic of)

    2004-02-15

    Natural radioisotopes contained in foods can enter the human body by ingestion and contribute to internal doses to the population. It is necessary to measure the concentration of natural radioisotopes especially thorium in Korean foods and estimate the internal doses. In this study, we have established the thorium measuring process based on the thorium extraction chemical process and alpha spectroscopic method. The concentration of Th-228, Th-230 and Th-232 in Korean vegetables (potato, sweet potato, radish, cabbage, hot pepper, garlic, onion and pumpkin) and fruits(apple, persimmon, orange, pear, grape) are measured and their internal doses are estimated.

  3. Distribution of Th-230 and Th-228 in food (I)

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hee Dong; Kim, Wan; Lim, X. J.; Choi, M. S.; Kim, C. J.; Zheng, Y. Z. [Kyungpook National Univ., Daegu (Korea, Republic of); Kim, Do Sung [Daegu Univ., Daegu (Korea, Republic of)

    2003-03-15

    Natural radioisotopes contained in foods can enter the human body by ingestion and contribute to internal doses to the population. It is necessary to measure the concentration of natural radioisotopes especially thorium in Korean foods and estimate the internal doses. In this study, we have established the thorium measuring process based on the thorium extraction chemical process and alpha spectroscopic method. The concentration of Th-228, Th-230 and Th-232 in Korean milk, meats(pork, beef and chicken) and grain (wheat, bean and rice) are measured and internal doses are estimated.

  4. Information Gathering Document 0321-1437-30-R-OG

    Energy Technology Data Exchange (ETDEWEB)

    Hollister, R

    2009-07-15

    Fines and turnings from machining depleted uranium (Dep-U), natural uranium (Nat-U), and Thorium-232, and stainless steel and aluminum. This IGO allows only small, oxidizable pieces of Dep-U/Nat-U/Th-232, with regulated metal contaminants below regulatory limits. Fines and turnings will be in 30 gallon vented drums immersed in mineral oil. The 30 gallon drums will be overpacked in 55 gallon vented drums. The waste will be stored on site until sent for stabilization & disposal with approved TSOFs.

  5. Determination of uranium concentration in ground water samples of Northern Greece

    Directory of Open Access Journals (Sweden)

    Pashalidis I.

    2012-04-01

    Full Text Available The activity concentration of 238U and 234U has been determined in groundwater samples of hot springs and deep wells from the region of Northern Greece. The analysis was performed by alpha spectroscopy after pre-concentration and separation of uranium by cation exchange (Chelex 100 resin and finally its electro-deposition on stainless steel discs. The uranium concentration in deep wells and springs varies strongly between 0.15 and 7.66 μg l−1. Generally the springs present higher uranium concentration than the deep wells, except of the Apol-lonia spring, which has shown the lowest value of 0.15 mg l−1. 238U and 234U activity concentration ranged between 1.8–95.3 mBq l−1 and 1.7–160.1 mBq l−1, respectively. The obtained isotopic ratio 234U/238U varies between 0.95 and 1.74 which means that the two isotopes are not in radioactive equilibrium. The highest 234U/238U activity ratio values correspond to the Langada springs, indicating most probably old-type waters. On the other hand, ground waters from wells with relatively low uranium activity concentration and low 234U/238U isotopic ratios, point to the presence of younger waters with a stronger contribution of a local recharge component to the groundwater.

  6. Prospects for improved understanding of isotopic reactor antineutrino fluxes

    Science.gov (United States)

    Gebre, Y.; Littlejohn, B. R.; Surukuchi, P. T.

    2018-01-01

    Predictions of antineutrino fluxes produced by fission isotopes in a nuclear reactor have recently received increased scrutiny due to observed differences in predicted and measured inverse beta decay (IBD) yields, referred to as the "reactor antineutrino flux anomaly." In this paper, global fits are applied to existing IBD yield measurements to produce constraints on antineutrino production by individual plutonium and uranium fission isotopes. We find that fits including measurements from highly U 235 -enriched cores and fits including Daya Bay's new fuel evolution result produce discrepant best-fit IBD yields for U 235 and Pu 239 . This discrepancy can be alleviated in a global analysis of all data sets through simultaneous fitting of Pu 239 , U 235 , and U 238 yields. The measured IBD yield of U 238 in this analysis is (7.02 ±1.65 )×10-43 cm2/fission , nearly two standard deviations below existing predictions. Future hypothetical IBD yield measurements by short-baseline reactor experiments are examined to determine their possible impact on the global understanding of isotopic IBD yields. It is found that future improved short-baseline IBD yield measurements at both high-enriched and low-enriched cores can significantly improve constraints for U 235 , U 238 , and Pu 239 , providing comparable or superior precision to existing conversion- and summation-based antineutrino flux predictions. Systematic and experimental requirements for these future measurements are also investigated.

  7. Depleted uranium analysis in blood by inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Todorov, T.I.; Xu, H.; Ejnik, J.W.; Mullick, F.G.; Squibb, K.; McDiarmid, M.A.; Centeno, J.A.

    2009-01-01

    In this study we report depleted uranium (DU) analysis in whole blood samples. Internal exposure to DU causes increased uranium levels as well as change in the uranium isotopic composition in blood specimen. For identification of DU exposure we used the 235U/238U ratio in blood samples, which ranges from 0.00725 for natural uranium to 0.002 for depleted uranium. Uranium quantification and isotopic composition analysis were performed by inductively coupled plasma mass spectrometry. For method validation we used eight spiked blood samples with known uranium concentrations and isotopic composition. The detection limit for quantification was determined to be 4 ng L-1 uranium in whole blood. The data reproduced within 1-5% RSD and an accuracy of 1-4%. In order to achieve a 235U/238U ratio range of 0.00698-0.00752% with 99.7% confidence limit a minimum whole blood uranium concentration of 60 ng L??1 was required. An additional 10 samples from a cohort of veterans exposed to DU in Gulf War I were analyzed with no knowledge of their medical history. The measured 235U/ 238U ratios in the blood samples were used to identify the presence or absence of DU exposure within this patient group. ?? 2009 The Royal Society of Chemistry.

  8. Chemical and radiochemical characterization of depleted uranium (DU) in Kosovo soils.

    Science.gov (United States)

    Desideri, Donatella; Meli, Maria Assunta; Roselli, Carla; Testa, Corrado

    2002-04-01

    As is well known ammunitions containing depleted uranium (DU) were used by NATO during the Balkan war. The paper deals with the determination of uranium alpha emitting radiosotopes in Kosovo soils by chemical separation and alpha spectrometry. The samples were collected by CISAM (Centro Interforze Studi ed Applicazioni Militari, S. Piero a Grado, Livorno) in the period November 1999-April 2000. The DU distribution in soil appeared very disomogeneous; the isotope weight percentages for U-238, U-235 and U-234 resulted 99.76, 0.24 and 7.24.10(-4) respectively; consequently the activity distribution was 86.42%, 1.31%, 11.63% and the isotope ratios were 1.52.10(-2) and 0.134 for U-235/U-238 and U-234/U-238 showing clearly the presence of DU. A small peak at 4.49 MeV (U-236) in the alpha spectrum indicated that the used DU was the by-product of exhausted uranium reprocessing. In order to determine the chemical and physiological solubility of uranium a fractionation study was carried out by using the Tessier method: 55% of uranium showed a fair solubility, but 45% was solubilized only by 8 M HNO3.

  9. Dissolved uranium, radium and radon evolution in the Continental Intercalaire aquifer, Algeria and Tunisia.

    Science.gov (United States)

    Elliot, Trevor; Bonotto, Daniel Marcos; Andrews, John Napier

    2014-11-01

    Natural, dissolved (238)U-series radionuclides (U, (226)Ra, (222)Rn) and activity ratios (A.R.s: (234)U/(238)U; (228)Ra/(226)Ra) in Continental Intercalaire (CI) groundwaters and limited samples from the overlying Complexe Terminal (CT) aquifers of Algeria and Tunisia are discussed alongside core measurements for U/Th (and K) in the contexts of radiological water quality, geochemical controls in the aquifer, and water residence times. A redox barrier is characterised downgradient in the Algerian CI for which a trend of increasing (234)U/(238)U A.R.s with decreasing U-contents due to recoil-dominated (234)U solution under reducing conditions allows residence time modelling ∼500 ka for the highest enhanced A.R. = 3.17. Geochemical modelling therefore identifies waters towards the centre of the Grand Erg Oriental basin as palaeowaters in line with reported (14)C and (36)Cl ages. A similar (234)U/(238)U trend is evidenced in a few of the Tunisian CI waters. The paleoage status of these waters is affirmed by both noble gas recharge temperatures and simple modelling of dissolved, radiogenic (4)He-contents both for sampled Algerian and Tunisian CI and CT waters. For the regions studied these waters therefore should be regarded as "fossil" waters and treated effectively as a non-renewable resource. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. The distribution of depleted uranium contamination in Colonie, NY, USA.

    Science.gov (United States)

    Lloyd, N S; Chenery, S R N; Parrish, R R

    2009-12-20

    Uranium oxide particles were dispersed into the environment from a factory in Colonie (NY, USA) by prevailing winds during the 1960s and '70s. Uranium concentrations and isotope ratios from bulk soil samples have been accurately measured using inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) without the need for analyte separation chemistry. The natural range of uranium concentrations in the Colonie soils has been estimated as 0.7-2.1 microg g(-1), with a weighted geometric mean of 1.05 microg g(-1); the contaminated soil samples comprise uranium up to 500+/-40 microg g(-1). A plot of (236)U/(238)U against (235)U/(238)U isotope ratios describes a mixing line between natural uranium and depleted uranium (DU) in bulk soil samples; scatter from this line can be accounted for by heterogeneity in the DU particulate. The end-member of DU compositions aggregated in these bulk samples comprises (2.05+/-0.06) x 10(-3)(235)U/(238)U, (3.2+/-0.1)x10(-5)(236)U/(238)U, and (7.1+/-0.3) x 10(-6)(234)U/(238)U. The analytical method is sensitive to as little as 50 ng g(-1) DU mixed with the natural uranium occurring in these soils. The contamination footprint has been mapped northward from site, and at least one third of the uranium in a soil sample from the surface 5 cm, collected 5. 1km NNW of the site, is DU. The distribution of contamination within the surface soil horizon follows a trend of exponential decrease with depth, which can be approximated by a simple diffusion model. Bioturbation by earthworms can account for dispersal of contaminant from the soil surface, in the form of primary uranium oxide particulates, and uranyl species that are adsorbed to organic matter. Considering this distribution, the total mass of uranium contamination emitted from the factory is estimated to be c. 4.8 tonnes.

  11. Uranium isotopes in tree bark as a spatial tracer of environmental contamination near former uranium processing facilities in southwest Ohio.

    Science.gov (United States)

    Conte, Elise; Widom, Elisabeth; Kuentz, David

    2017-11-01

    HHM transects exhibit increasing U concentrations within ∼5 and ∼10 km, respectively of the FFMPC. The 236U/238U isotopic ratios in tree bark from both transects increase progressively towards the FFMPC with values as high as 2.00 × 10-4 at the FFMPC. Tree bark sampled within 1 km of the FFMPC exhibits clear evidence for both enriched and depleted uranium with 235U/238U values from 0.00461 to 0.00736, with 234U/238U activity ratio ranging from 0.53 to 0.96, and 236U/238U from 6.05 × 10-5 to 1.05 × 10-4. Tree bark from transect #1 between 1 and 30 km from the FFMPC exhibits depleted and natural 235U/238U values ranging from 0.00552 to 0.00726 [234U/238U activity ratio: 0.69-1.04; 236U/238U: 2.49 × 10-6 - 2.00 × 10-4]. Tree bark from transect #2 sampled between 1 and ∼20 km away from the FFMPC exhibits evidence of enriched and depleted U in the environment with 235U/238U ranging from 0.00635 to 0.00738 [234U/238U activity ratio: 0.83-0.98; 236U/238U: 1.43 × 10-5 - 2.00 × 10-4]. Results from scanning electron microscopy with energy dispersive spectrometry provides evidence for U-rich particles as the source of contamination found in tree bark growing within 1-3 km of the former FFMPC. Such observations are consistent with the previously observed 14 μm U-rich particle identified in tree bark sampled within 1 km of the FFMPC (Conte et al., 2015). Overall, this study shows the usefulness of a tree bark sample transect to assess the areal extent of atmospheric contaminant U stemming from nuclear facilities. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Battelle-Northwest monthly activities report, March 1965

    Energy Technology Data Exchange (ETDEWEB)

    1965-04-15

    This report covers progress in the following areas: production reactor support; plutonium recycle program; PRTR HPD core; corrosion and water quality; PRTR pressure tubes; reactor components development; plutonium ceramics research; ceramics (uranium) fuel research; swelling studies; irradiation damage to reactor materials; ATR gas loop studies; graphite studies; metallic fuel development; plutonium and U-233 fueling of a fast compact reactor; FFTF studies; radiation effects on metals; customer work (support of HTLTR and EBWR); physics and instruments; chemistry; biology; radiation protection; and technical and other services.

  13. RADIOACTIVE WASTE STREAMS FROM VARIOUS POTENTIAL NUCLEAR FUEL CYCLE OPTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Nick Soelberg; Steve Piet

    2010-11-01

    Five fuel cycle options, about which little is known compared to more commonly known options, have been studied in the past year for the United States Department of Energy. These fuel cycle options, and their features relative to uranium-fueled light water reactor (LWR)-based fuel cycles, include: • Advanced once-through reactor concepts (Advanced Once-Through, or AOT) – intended for high uranium utilization and long reactor operating life, use depleted uranium in some cases, and avoid or minimize used fuel reprocessing • Fission-fusion hybrid (FFH) reactor concepts – potential variations are intended for high uranium or thorium utilization, produce fissile material for use in power generating reactors, or transmute transuranic (TRU) and some radioactive fission product (FP) isotopes • High temperature gas reactor (HTGR) concepts - intended for high uranium utilization, high reactor thermal efficiencies; they have unique fuel designs • Molten salt reactor (MSR) concepts – can breed fissile U-233 from Th fuel and avoid or minimize U fuel enrichment, use on-line reprocessing of the used fuel, produce lesser amounts of long-lived, highly radiotoxic TRU elements, and avoid fuel assembly fabrication • Thorium/U-233 fueled LWR (Th/U-233) concepts – can breed fissile U-233 from Th fuel and avoid or minimize U fuel enrichment, and produce lesser amounts of long-lived, highly radiotoxic TRU elements. These fuel cycle options could result in widely different types and amounts of used or spent fuels, spent reactor core materials, and waste streams from used fuel reprocessing, such as: • Highly radioactive, high-burnup used metal, oxide, or inert matrix U and/or Th fuels, clad in Zr, steel, or composite non-metal cladding or coatings • Spent radioactive-contaminated graphite, SiC, carbon-carbon-composite, metal, and Be reactor core materials • Li-Be-F salts containing U, TRU, Th, and fission products • Ranges of separated or un-separated activation

  14. The late-stage "ferruginization" of the Ediacara Member (Rawnsley Quartzite, South Australia): Insights from uranium isotopes.

    Science.gov (United States)

    Tarhan, L G; Planavsky, N J; Wang, X; Bellefroid, E J; Droser, M L; Gehling, J G

    2018-01-01

    The paleoenvironmental setting in which the Ediacara Biota lived, died, and was preserved in the eponymous Ediacara Member of the Rawnsley Quartzite of South Australia is an issue of long-standing interest and recent debate. Over the past few decades, interpretations have ranged from deep marine to shallow marine to terrestrial. One of the key features invoked by adherents of the terrestrial paleoenvironment hypothesis is the presence of iron oxide coatings, inferred to represent the upper horizons of paleosols, along fossiliferous sandstone beds of the Ediacara Member. We find that these surficial oxides are characterized by ( 234 U/ 238 U) values which are not in secular equilibrium, indicating extensive fluid-rich alteration of these surfaces within the past approximately 2 million years. Specifically, the oxide coatings are characterized by ( 234 U/ 238 U) values >1, indicating interaction with high-( 234 U/ 238 U) fluids derived from alpha-recoil discharge. These oxides are also characterized by light "stable" δ 238/235 U values, consistent with a groundwater U source. These U isotope data thus corroborate sedimentological observations that ferric oxides along fossiliferous surfaces of the Ediacara Member consist of surficial, non-bedform-parallel staining, and sharply irregular patches, strongly reflecting post-depositional, late-stage processes. Therefore, both sedimentological and geochemical evidence indicate that Ediacara iron oxides do not reflect synsedimentary ferruginization and that the presence of iron oxides cannot be used to either invoke a terrestrial paleoenvironmental setting for or reconstruct the taphonomic pathways responsible for preservation of the Ediacara Biota. These findings demonstrate that careful assessment of paleoenvironmental parameters is essential to the reconstruction of the habitat of the Ediacara Biota and the factors that led to the fossilization of these early complex ecosystems. © 2017 John Wiley & Sons Ltd.

  15. Solid matrix transformation and tracer addition using molten ammonium bifluoride salt as a sample preparation method for laser ablation inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Grate, Jay W; Gonzalez, Jhanis J; O'Hara, Matthew J; Kellogg, Cynthia M; Morrison, Samuel S; Koppenaal, David W; Chan, George C-Y; Mao, Xianglei; Zorba, Vassilia; Russo, Richard E

    2017-09-08

    Solid sampling and analysis methods, such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), are challenged by matrix effects and calibration difficulties. Matrix-matched standards for external calibration are seldom available and it is difficult to distribute spikes evenly into a solid matrix as internal standards. While isotopic ratios of the same element can be measured to high precision, matrix-dependent effects in the sampling and analysis process frustrate accurate quantification and elemental ratio determinations. Here we introduce a potentially general solid matrix transformation approach entailing chemical reactions in molten ammonium bifluoride (ABF) salt that enables the introduction of spikes as tracers or internal standards. Proof of principle experiments show that the decomposition of uranium ore in sealed PFA fluoropolymer vials at 230 °C yields, after cooling, new solids suitable for direct solid sampling by LA. When spikes are included in the molten salt reaction, subsequent LA-ICP-MS sampling at several spots indicate that the spikes are evenly distributed, and that U-235 tracer dramatically improves reproducibility in U-238 analysis. Precisions improved from 17% relative standard deviation for U-238 signals to 0.1% for the ratio of sample U-238 to spiked U-235, a factor of over two orders of magnitude. These results introduce the concept of solid matrix transformation (SMT) using ABF, and provide proof of principle for a new method of incorporating internal standards into a solid for LA-ICP-MS. This new approach, SMT-LA-ICP-MS, provides opportunities to improve calibration and quantification in solids based analysis. Looking forward, tracer addition to transformed solids opens up LA-based methods to analytical methodologies such as standard addition, isotope dilution, preparation of matrix-matched solid standards, external calibration, and monitoring instrument drift against external calibration standards.

  16. Modeling non-steady state radioisotope transport in the vadose zone - A case study using uranium isotopes at Peña Blanca, Mexico

    Science.gov (United States)

    Ku, T. L.; Luo, S.; Goldstein, S. J.; Murrell, M. T.; Chu, W. L.; Dobson, P. F.

    2009-10-01

    Current models using U- and Th-series disequilibria to study radioisotope transport in groundwater systems mostly consider a steady-state situation. These models have limited applicability to the vadose zone (UZ) where the concentration and migratory behavior of radioisotopes in fluid are often transitory. We present here, as a first attempt of its kind, a model simulating the non-steady state, intermittent fluid transport in vadose layers. It provides quantitative constraints on in-situ migration of dissolved and colloidal radioisotopes in terms of retardation factor and rock-water interaction (or water transit) time. For uranium, the simulation predicts that intermittent flushing in the UZ leads to a linear relationship between reciprocal U concentration and 234U/ 238U ratio in percolating waters, with the intercept and slope bearing information on the rates of dissolution and α-recoil of U isotopes, respectively. The general validity of the model appears to be borne out by the measurement of uranium isotopes in UZ waters collected at various times over a period during 1995-2006 from a site in the Peña Blanca mining district, Mexico, where the Nopal I uranium deposit is located. Enhanced 234U/ 238U ratios in vadose-zone waters resulting from lengthened non-flushing time as prescribed by the model provide an interpretative basis for using 234U/ 238U in cave calcites to reconstruct the regional changes in hydrology and climate. We also provide a theoretical account of the model's potential applications using radium isotopes.

  17. Uranium-series dating of pedogenic silica and carbonate, Crater Flat, Nevada

    Science.gov (United States)

    Ludwig, K. R.; Paces, J.B.

    2002-01-01

    A 230Th-234U-238U dating study on pedogenic silica-carbonate clast rinds and matrix laminae from alluvium in Crater Flat, Nevada was conducted using small-sample thermal-ionization mass spectrometry (TIMS) analyses on a large suite of samples. Though the 232Th content of these soils is not particularly low (mostly 0.1-9 ppm), the high U content of the silica component (mostly 4-26 ppm) makes them particularly suitable for 230Th/U dating on single, 10 to 200 mg totally-digested samples using TIMS. We observed that (1) both micro- (within-rind) and macro-stratigraphic (mappabe deposit) order of the 230Th/U ages were preserved in all cases; (2) back-calculated initial 234U/238U fall in a restricted range (typically 1.67??0.19), so that 234U/238U ages with errors of about 100 kyr (2??) could be reliably determined for the oldest, 400 to 1000 ka rinds: and (3) though 13 of the samples were >350 ka, only three showed evidence for an open-system history, even though the sensitivity of such old samples to isotopic disruption is very high. An attempt to use leach-residue techniques to separate pedogenic from detrital U and Th failed, yielding corrupt 230Th/U ages. We conclude that 230Th/U ages determined from totally dissolved, multiple sub-mm size subsamples provide more reliable estimates of soil chronology than methods employing larger samples, chemical enhancement of 238U/232Th, or isochrons. Copyright ?? 2002 Elsevier Science Ltd.

  18. Determination of plutonium-239, thorium-232, and natural uranium isotopic concentrations in biological samples using photofission track analysis

    Science.gov (United States)

    Parry, James Roswell

    Fission track analysis (FTA) has many uses in the scientific community including but not limited to geological dating, neutron flux mapping, and dose reconstruction. The common method of fission for FTA is through neutrons from a nuclear reactor. This dissertation investigates the use of bremsstrahlung radiation produced from an electron linear accelerator to induce fission in FTA samples. This provides a means of simultaneously measuring the amount of Pu-239, U-nat, and Th-232 in a single sample. The benefit of measuring the three isotopes simultaneously is the possible elimination of costly and time consuming chemical processing for dose reconstruction samples. Samples containing the three isotopes were irradiated in two different bremsstrahlung spectra and a neutron spectrum to determine the amount of Pu-239, U-nat, and Th-232 in the samples. The reaction rate from the calibration samples and the counted fission tracks on the samples were used in determining the concentration of each isotope in the samples. The results were accurate to within a factor of two or three, showing that the method can work to predict the concentrations of multiple isotopes in a sample. The limitations of current accelerators and detectors limits the application of this specific procedure to higher concentrations of isotopes. The method detection limits for Pu-239, U-nat, and Th-232 are 20 pCi, 1 fCi, and 0.4 flCI respectively. Analysis of extremely low concentrations of isotopes would require the use of different detectors such as quartz due to the embrittlement encountered in the Lexan at high exposures. Cracking of the Texan detectors started to appear at a fluence of about 2 x 1018 electrons from the accelerator. This may be partly due to the beam stop not being an adequate thickness. The procedure is likely limited to specialty applications for the near term. However, with the world concerns of exposure to depleted uranium, this procedure may find applications in this area since

  19. High-precision Measurement of the 238U(n,γ) Cross Section with the Total Absorption Calorimeter (TAC) at n_TOF, CERN

    CERN Document Server

    Wright, T; Billowes, J; Ware, T; Cano-Ott, D; Mendoza, E; Massimi, C; Mingrone, F; Gunsing, F; Berthoumieux, E; Lampoudis, C; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Bécares, V; Bečvář, F; Belloni, F; Boccone, V; Bosnar, D; Brugger, M; Calviani, M; Calviño, F; Carrapiço, C; Cerutti, F; Chiaveri, E; Chin, M; Colonna, N; Cortés, G; Cortés-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Dzysiuk, N; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; García, A R; Gómez-Hornillos, M B; Gonçalves, I F; González-Romero, E; Griesmayer, E; Giubrone, G; Gurusamy, P; Jenkins, D G; Jericha, E; Kadi, Y; Käppeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Korschinek, G; Krtička, M; Kroll, J; Langer, C; Lederer, C; Leeb, H; Leong, L S; Losito, R; Manousos, A; Marganiec, J; Martínez, T; Mastinu, P F; Mastromarco, M; Meaze, M; Mengoni, A; Milazzo, P M; Mirea, M; Mondelaers, W; Paradela, C; Pavlik, A; Perkowski, J; Pignatari, M; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Weigand, M; Weiß, C; Žugec, P

    2014-01-01

    The neutron capture cross section of U-238 is fundamental to the design and operation of current reactors and future fast nuclear reactors, and thus must be measured to a high level of accuracy. An experiment has been performed at the CERN n TOF facility using a 4 pi Total Absorption Calorimeter (TAC) to measure the capture cross section in the resolved resonance region between 1 eV and 25 keV. A preliminary analysis of the TAC data is presented with particular emphasis to the experimental background in this energy region of interest.

  20. Stability of a nanofiltration membrane after contact with a low-level liquid radioactive waste

    Directory of Open Access Journals (Sweden)

    Elizabeth Eugenio de Mello Oliveira

    2013-01-01

    Full Text Available This study investigated the treatment of a liquid radioactive waste containing uranium (235U + 238U using nanofiltration membranes. The membranes were immersed in the waste for 24-5000 h, and their transport properties were evaluated before and after the immersion. Surface of the membranes changed after immersion in the waste. The SW5000 h specimen lost its coating layer of polyvinyl alcohol, and its rejection of sulfate ions and uranium decreased by about 35% and 30%, respectively. After immersion in the waste, the polyamide selective layer of the membranes became less thermally stable than that before immersion.

  1. Studies of the Vertical Distribution of Cs-134, Cs-137, Pu-238, Pu-239,240, Pu-241, Am-241 and Pb-210 in ombrogenous mires in Ireland

    Science.gov (United States)

    McGarry, A. T.; Mitchell, P. I.

    The technique of using Pb-210, a member of the naturally occurring U-238 chain, as a dating tool, has been widely used since the 1960's and has been shown to be reliable when applied to ombrotrophic peat bogs. Its application rests on two fundamental assumptions (a) that the flux of Pb-210 is constant when averaged over periods of at least a few years and (b) that Pb-210 is essentially immobile in peat over the range of natural conditions usually encountered…

  2. Progress and Expectations for the NIFFTE Fission TPC

    Science.gov (United States)

    Seilhan, Brandon

    2012-11-01

    The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) aims to improve current neutron-induced fission cross-section measurements through the use of a purpose-built Time Projection Chamber (TPC). Recent improvements to the fission TPC, including a sixfold increase in instrumented area and the capability to determine neutron time-of-flight, improve the ability of the fission TPC to precisely measure fission cross-sections. The current status including updates on the measurement of the cross section ratio for U-238 to U-235 and Pu-239 to U-235 will be discussed.

  3. Electrodeposition of selected alpha-emitting nuclides from ammonium acetate electrolyte

    Science.gov (United States)

    Lee, Shan C.; Choi, Jae G.; Hodge, Vernon F.

    1994-10-01

    The experimentally optimal conditions of the electrodeposition of selected alpha particle-emitting radionuclides, including Po-208, Ra-226, Th-228, U-238, Pu-239, Am-241 and Cm-(243, 244) with ammonium acetate electrolyte have been determined. This simple method could be used for the determination of the most important actinides in radiological waste and could be applicable to waste treatment. In addition, this method could be used for radium determination instead of the traditional radon emanation technique, which requires approximately 30 days.

  4. Copper and manganese in loggerhead turtles (Caretta caretta tissues in the Mediterranean

    Directory of Open Access Journals (Sweden)

    Z.K. ANTONIOU

    2004-06-01

    Full Text Available The natural radionuclides 238U ,234Th, 40K and the main man-made 137Cs, have been studied inMytilus galloprovincialis (Lamarck, 1819 sampled in the Thermaikos gulf – North Aegean Sea, considered as a bioindicator for radiological assessment in the Mediterranean. The ratio 234U/238U has also been determined. In terms of 137Cs, the activity concentrations in seawater from the studied area have been measured as well, and the concentration factors of 137Cs in Mytilus galloprovincialis are given as a parameter of the organism response to radioactive pollution.

  5. Eclogite-high-pressure granulite metamorphism records early collision in West Gondwana: new data from the Southern Brasilia Belt, Brazil

    DEFF Research Database (Denmark)

    Reno II, Barry Len; Brown, Michael; Kobayashi, Katsura

    2009-01-01

    constrain the age of. (1) retrograded eclogite from a block along the tectonic contact beneath the uppermost nappe in a stack of passive margin-derived nappes; (2) high-pressure granulite-facies metamorphism in the uppermost passive margin-derived nappe; (3) high-pressure granulite-facies metamorphism...... in the overlying arc-derived nappe. Rare zircons from a retrograded eclogite yield a Pb-206/U-238 age of 678 +/- 29 Ma. which we interpret as most likely to (late close-to-peak-P metamorphism and to provide a minimum age for detachment of the overlying passive margin-derived nappe from the subducting plate. Zircon...

  6. Isomeric decay spectroscopy of the Bi217 isotope

    Science.gov (United States)

    Gottardo, A.; Valiente-Dobón, J. J.; Benzoni, G.; Lunardi, S.; Gadea, A.; Algora, A.; Al-Dahan, N.; de Angelis, G.; Ayyad, Y.; Bazzacco, D.; Benlliure, J.; Boutachkov, P.; Bowry, M.; Bracco, A.; Bruce, A. M.; Bunce, M.; Camera, F.; Casarejos, E.; Cortes, M. L.; Crespi, F. C. L.; Corsi, A.; Denis Bacelar, A. M.; Deo, A. Y.; Domingo-Pardo, C.; Doncel, M.; Engert, T.; Eppinger, K.; Farrelly, G. F.; Farinon, F.; Farnea, E.; Geissel, H.; Gerl, J.; Goel, N.; Górska, M.; Grebosz, J.; Gregor, E.; Habermann, T.; Hoischen, R.; Janik, R.; John, P. R.; Klupp, S.; Kojouharov, I.; Kurz, N.; Lenzi, S. M.; Leoni, S.; Mandal, S.; Menegazzo, R.; Mengoni, D.; Million, B.; Modamio, V.; Morales, A. I.; Napoli, D. R.; Naqvi, F.; Nicolini, R.; Nociforo, C.; Pfützner, M.; Pietri, S.; Podolyák, Zs.; Prochazka, A.; Prokopowicz, W.; Recchia, F.; Regan, P. H.; Reed, M. W.; Rudolph, D.; Sahin, E.; Schaffner, H.; Sharma, A.; Sitar, B.; Siwal, D.; Steiger, K.; Strmen, P.; Swan, T. P. D.; Szarka, I.; Ur, C. A.; Walker, P. M.; Weick, H.; Wieland, O.; Wollersheim, H.-J.

    2014-09-01

    The structure of the neutron-rich bismuth isotope Bi217 has been studied for the first time. The fragmentation of a primary U238 beam at the FRS-RISING setup at GSI was exploited to perform γ-decay spectroscopy, since μs isomeric states were expected in this nucleus. Gamma rays following the decay of a t1/2=3 μs isomer were observed, allowing one to establish the low-lying structure of Bi217. The level energies and the reduced electric quadrupole transition probability B (E2) from the isomeric state are compared to large-scale shell-model calculations.

  7. Weld Development for Aluminum Fission Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Cross, Carl Edward [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez, Jesse Norris [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-16

    The Sigma welding team was approached to help fabricate a small fission chamber (roughly ½ inch dia. x ½ inch tall cylinder). These chambers are used as radiation sensors that contain small traces of radionuclides (Cf 252, U 235, and U 238) that serve to ionize gas atoms in addition to external radiation. When a voltage is applied within the chamber, the resulting ion flow can be calibrated and monitored. Aluminum has the advantage of not forming radioactive compounds when exposed to high external radiation (except from minor Na alloy content). Since aluminum has not been used before in this application, this presented an unexplored challenge.

  8. Modeling multi-nucleon transfer in symmetric collisions of massive nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Welsh, T.; Loveland, W.; Yanez, R.; Barrett, J. S.; McCutchan, E. A.; Sonzogni, A. A.; Johnson, T.; Zhu, S.; Greene, J. P.; Ayangeakaa, A. D.; Carpenter, M. P.; Lauritsen, T.; Harker, J. L.; Walters, W. B.; Amro, B. M. S.; Copp, P.

    2017-08-01

    Symmetric collisions of massive nuclei, such as U-238 + Cm-248, have been proposed as ways to make new n-rich heavy nuclei via multi-nucleon transfer (MNT) reactions. We have measured the yields of several projectile-like and target-like fragments from the reaction of 1360 MeV Hg-204 + Pt-198. We find that current models for this symmetric collision (GRAZING, DNS, ImQMD) significantly underestimate the yields of these transfer products, even for small transfers. (C) 2017 The Author(s). Published by Elsevier B.V.

  9. 2004 Initial Assessments of Closure for the S-SX Tank Farm: Numerical Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z F; Freedman, Vicky L; Waichler, Scott R; White, Mark D

    2004-04-01

    In support of CH2M HILL Hanford Group, Inc.'s (CHG) preparation of a Field Investigative Report (FIR) for the closure of the Hanford Site Single-Shell Tank (SST) Waste Management Area (WMA) tank farms, a set of numerical simulations of flow and solute transport was executed to investigate different potential contaminant source scenarios that may pose long-term risks to groundwater from the closure of the S-SX Tank Farm. This report documents the simulation of 7 cases (plus two verification) involving two-dimensional cross sections through the S Tank Farm (Tanks S-101, S102, and S-103) and the simulation of one case involving three-dimensional domain of the S Tank Farm. Using a unit release scenario at Tank S-103, three different types of leaks were simulated. These simulations assessed the effect of leaks during retrieval as well as residual wastes and ancillary equipment after closure. Two transported solutes were considered: uranium-238 (U-238) and technetium-99 (Tc 99). To evaluate the effect of sorption on contaminant transport, six different sorption coefficients were simulated for U 238. Overall, simulations results for the S Tank Farm showed that only a small fraction (< 0.4%) of the U-238 with sorption coefficients 0.6 mL/g migrated from the vadose zone in all of the cases. For the conservative solute, Tc-99, results showed that the simulations investigating leaks during retrieval demonstrated the highest peak concentrations and the earliest arrival times due to the high infiltration rate before water was added and surface barriers installed. Residual leaks were investigated with different release rate models, including uniform release, advection-dominated, diffusion-dominated, and saltcake (solubility-controlled) release models. Of the four models, peak concentrations were lowest and arrival times later for the uniform release model due to the lower release rate of the residual tank waste solids; similar high peak concentrations occurred for the

  10. Study Of Thorium As A Nuclear Fuel.

    Directory of Open Access Journals (Sweden)

    Prakash Humane

    2017-10-01

    Full Text Available Conventional fuel sources for power generation are to be replacing by nuclear power sources like nuclear fuel Uranium. But Uranium-235 is the only fissile fuel which is in 0.72 found in nature as an isotope of Uranium-238. U-238 is abundant in nature which is not fissile while U-239 by alpha decay naturally converted to Uranium- 235. For accompanying this nuclear fuel there is another nuclear fuel Thorium is present in nature is abundant can be used as nuclear fuel and is as much as safe and portable like U-235.

  11. CHEMICAL TOXICITY OF URANIUM

    Directory of Open Access Journals (Sweden)

    Sermin Cam

    2007-06-01

    Full Text Available Uranium, occurs naturally in the earth’s crust, is an alpha emitter radioactive element from the actinide group. For this reason, U-235 and U-238, are uranium isotopes with long half lives, have got radiological toxicity. But, for natural-isotopic-composition uranium (NatU, there is greater risk from chemical toxicity than radiological toxicity. When uranium is get into the body with anyway, also its chemical toxicity must be thought. [TAF Prev Med Bull 2007; 6(3.000: 215-220

  12. A preliminary evaluation of naturally occurring radioactivity concentration levels across the State of Kuwait.

    Science.gov (United States)

    Shams, H; Bajoga, A D; Alazemi, N; Bradley, D A; Regan, P H

    2016-03-01

    An evaluation of naturally occurring radioactive materials has been undertaken as part of a systematic study to provide a surface radiological map of the State of Kuwait. Soil samples were collected from twelve locations across Kuwait and analysed using high-resolution gamma-ray spectrometry. The (226)Ra and (235)U specific activity concentrations have been determined and used to estimate the (235)U/(238)U isotopic ratios which are found to be comparable to that expected for naturally occurring uranium material. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. $\\beta$-decay study of $^{77}$Cu

    CERN Document Server

    Patronis, N; Górska, M; Huyse, M; Kruglov, K; Pauwels, D; Van de Vel, K; Van Duppen, P; Van Roosbroeck, J; Thomas, J-C; Franchoo, S; Cederkäll, J; Fedosseev, V; Fynbo, H; Georg, U; Jonsson, O; Köster, U; Materna, T; Mathieu, L; Serot, O; Weissman, L; Müller, W F; Mishin, V I; Fedorov, D

    2009-01-01

    A beta-decay study of Cu-77 has been performed at the ISOLDE mass separator with the aim to deduce its beta-decay properties and to obtain spectroscopic information on Zn-77. Neutron-rich copper isotopes were produced by means of proton- or neutron-induced fission reactions on U-238. After the production, Cu-77 was selectively laser ionized, mass separated and sent to different detection systems where beta-gamma and beta-n coincidence data were collected. We report on the deduced half-live, decay scheme, and possible spin assignment of 77Cu.

  14. Uranium isotopes and dissolved organic carbon in loess permafrost: Modeling the age of ancient ice

    Science.gov (United States)

    Ewing, Stephanie A.; Paces, James B.; O'Donnell, J.A.; Jorgenson, M.T.; Kanevskiy, M.Z.; Aiken, George R.; Shur, Y.; Harden, Jennifer W.; Striegl, Robert G.

    2015-01-01

    The residence time of ice in permafrost is an indicator of past climate history, and of the resilience and vulnerability of high-latitude ecosystems to global change. Development of geochemical indicators of ground-ice residence times in permafrost will advance understanding of the circumstances and evidence of permafrost formation, preservation, and thaw in response to climate warming and other disturbance. We used uranium isotopes to evaluate the residence time of segregated ground ice from ice-rich loess permafrost cores in central Alaska. Activity ratios of 234U vs. 238U (234U/238U) in water from thawed core sections ranged between 1.163 and 1.904 due to contact of ice and associated liquid water with mineral surfaces over time. Measured (234U/238U) values in ground ice showed an overall increase with depth in a series of five neighboring cores up to 21 m deep. This is consistent with increasing residence time of ice with depth as a result of accumulation of loess over time, as well as characteristic ice morphologies, high segregated ice content, and wedge ice, all of which support an interpretation of syngenetic permafrost formation associated with loess deposition. At the same time, stratigraphic evidence indicates some past sediment redistribution and possibly shallow thaw among cores, with local mixing of aged thaw waters. Using measures of surface area and a leaching experiment to determine U distribution, a geometric model of (234U/238U) evolution suggests mean ages of up to ∼200 ky BP in the deepest core, with estimated uncertainties of up to an order of magnitude. Evidence of secondary coatings on loess grains with elevated (234U/238U) values and U concentrations suggests that refinement of the geometric model to account for weathering processes is needed to reduce uncertainty. We suggest that in this area of deep ice-rich loess permafrost, ice bodies have been preserved from the last glacial period (10–100 ky BP), despite subsequent

  15. The fusion-supported decentralized nuclear energy system

    Science.gov (United States)

    Jassby, D. L.

    1981-01-01

    A decentralized nuclear energy system is proposed comprising mass-produced pressurized water reactors in the size range 10 to 300 MW (thermal), to be used for the production of process heat, space heat, and electricity in applications where petroleum and natural gas are presently used. Special attention is given to maximizing the refueling interval with no interim batch shuffling in order to minimize fuel transport, reactor downtime, and opportunity for fissile diversion. The smallest reactors could be deployed as “nuclear batteries,” kept in the equivalent of spent-fuel shipping casks and returned to nuclear fuel centers for refueling. These objectives demand a substantial fissile enrichment (7 to 15%). The preferred fissile fuel is U-233, which offers an order of magnitude savings in ore requirements (compared with U-235 fuel), and whose higher conversion ratio in thermal reactors serves to extend the period of useful reactivity and relieve demand on the fissile breeding plants (compared with Pu-239 fuel). Application of the neutral-beam-driven tokamak fusion-neutron source to a U-233 breeding pilot plant is examined. This scheme can be extended in part to a decentralized fusion energy system, wherein remotely located large fusion reactors supply excess tritium to a distributed system of relatively small nonbreeding D-T reactors.

  16. Gas core reactors for actinide transmutation and breeder applications. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Clement, J.D.; Rust, J.H.

    1978-04-01

    This work consists of design power plant studies for four types of reactor systems: uranium plasma core breeder, uranium plasma core actinide transmuter, UF6 breeder and UF6 actinide transmuter. The plasma core systems can be coupled to MHD generators to obtain high efficiency electrical power generation. A 1074 MWt UF6 breeder reactor was designed with a breeding ratio of 1.002 to guard against diversion of fuel. Using molten salt technology and a superheated steam cycle, an efficiency of 39.2% was obtained for the plant and the U233 inventory in the core and heat exchangers was limited to 105 Kg. It was found that the UF6 reactor can produce high fluxes (10 to the 14th power n/sq cm-sec) necessary for efficient burnup of actinide. However, the buildup of fissile isotopes posed severe heat transfer problems. Therefore, the flux in the actinide region must be decreased with time. Consequently, only beginning-of-life conditions were considered for the power plant design. A 577 MWt UF6 actinide transmutation reactor power plant was designed to operate with 39.3% efficiency and 102 Kg of U233 in the core and heat exchanger for beginning-of-life conditions.

  17. Simulation on reactor TRIGA Puspati core kinetics fueled with thorium (Th) based fuel element

    Science.gov (United States)

    Mohammed, Abdul Aziz; Pauzi, Anas Muhamad; Rahman, Shaik Mohmmed Haikhal Abdul; Zin, Muhamad Rawi Muhammad; Jamro, Rafhayudi; Idris, Faridah Mohamad

    2016-01-01

    In confronting global energy requirement and the search for better technologies, there is a real case for widening the range of potential variations in the design of nuclear power plants. Smaller and simpler reactors are attractive, provided they can meet safety and security standards and non-proliferation issues. On fuel cycle aspect, thorium fuel cycles produce much less plutonium and other radioactive transuranic elements than uranium fuel cycles. Although not fissile itself, Th-232 will absorb slow neutrons to produce uranium-233 (233U), which is fissile. By introducing Thorium, the numbers of highly enriched uranium fuel element can be reduced while maintaining the core neutronic performance. This paper describes the core kinetic of a small research reactor core like TRIGA fueled with a Th filled fuel element matrix using a general purpose Monte Carlo N-Particle (MCNP) code.

  18. Shallow and deep crustal control on differentiation of calc-alkaline and tholeiitic magma

    Science.gov (United States)

    Hora, John M.; Singer, Brad S.; Wörner, Gerhard; Beard, Brian L.; Jicha, Brian R.; Johnson, Clark M.

    2009-07-01

    The role of changing crustal interaction and plumbing geometry in modulating calc-alkaline vs. tholeiitic magma affinity is well illustrated by the influence of 70 km thick crust beneath Volcán Parinacota. Changes in petrologic affinity correlate with periods of cone-building, sector collapse, and rebuilding of the volcano over the last 52 ka, and are well explained by changes in magma recharge regime. With increasing recharge and magma output, lavas transition from low-Fe, strongly calc-alkaline, phenocryst-rich silicic compositions to medium-Fe, near-tholeiitic, mafic, and aphanitic characteristics. Strontium isotope data show that the change in magma regime did not affect all parts of the system simultaneously; these are characterized by distinctive 87Sr/ 86Sr ratios, which suggest an initially compartmentalized system. Relatively high ( 230Th/ 232Th) activity ratios of ~ 0.72 in early-erupted calc-alkaline lavas are consistent with interaction with high-U upper crust. Low ( 230Th/ 232Th) activity ratios of ~ 0.55 and up to 33% Th-excess in younger near-tholeiitic lavas correlate with steep REE patterns, indicating lower-crustal interaction. Thorium-excesses at the time of eruption approach the maximum that can be generated via small-degree garnet-residual melting in the lower crust or mantle and imply that transit time through the crustal column for the most tholeiitic magmas had to be short, on the order of secular equilibrium, suggesting stagnation times > 3 × 10 5 yr in the upper crust. In addition to more traditional explanations tied to magma source, expression of low-Fe 'calc-alkaline' (CA) vs. medium-Fe 'near-tholeiitic' (TH) magma series at the scale of individual volcanoes is likely to be modulated by transitions from compartmentalized, stagnant, assimilation-prone 'dirty' systems (CA) to 'clean' systems (TH) that are characterized by rapid magma throughput and minimal opportunity for upper-crustal contamination.

  19. Radioactivity in wastes generated from shale gas exploration and production - North-Eastern Poland.

    Science.gov (United States)

    Jodłowski, Paweł; Macuda, Jan; Nowak, Jakub; Nguyen Dinh, Chau

    2017-09-01

    In the present study, the K-40, U-238, Ra-226, Pb-210, Ra-228 and Th-228 activity concentrations were measured in 64 samples of wastes generated from shale gas exploration in North-Eastern Poland. The measured samples consist of drill cuttings, solid phase of waste drilling muds, fracking fluids, return fracking fluids and waste proppants. The measured activity concentrations in solid samples vary in a wide range from 116 to around 1100 Bq/kg for K-40, from 14 to 393 Bq/kg for U-238, from 15 to 415 Bq/kg for Ra-226, from 12 to 391 Bq/kg for Pb-210, from a few Bq/kg to 516 Bq/kg for Ra-228 and from a few Bq/kg to 515 Bq/kg for Th-228. Excluding the waste proppants, the measured activity concentrations in solid samples oscillate around their worldwide average values in soil. In the case of the waste proppants, the activity concentrations of radionuclides from uranium and thorium decay series are significantly elevated and equal to several hundreds of Bq/kg but it is connected with the mineralogical composition of proppants. The significant enhancement of Ra-226 and Ra-228 activity concentrations after fracking process was observed in the case of return fracking fluids, but the radium isotopes content in these fluids is comparable with that in waste waters from copper and coal mines in Poland. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The U-Th isotopic composition of Australian aeolian deposits: implications for weathering and sediment transport timescales

    Science.gov (United States)

    Handley, Heather; Turner, Simon; Hesse, Paul; Othayoth Suresh, Puthiyaveetil; Turner, Michael

    2017-04-01

    In order to quantify how fast a landscape responds to tectonic, climatic and human factors, accurate weathering rates and soil and/or sediment ages are required. The uranium-series (U-series) isotopes are a valuable tool for deriving the timescales of weathering and erosion processes. The impact of dust on calculated U-series isotope residence timescales of soil and fluvial sediment has received little attention to date, despite the fact that the typical grain size of aeolian material overlaps with that of interest in such studies, particularly for the comminution approach (Australia. We show that there is significant isotopic disequilibria in the samples, which are characterised by (230Th/238U) activity ratios > 1 and (234U/238U) activity ratios < 1. The finer-grained fractions (<5 microns) have higher (230Th/238U) but comparable (234U/238U) to the coarser-grained fractions (5-53 microns) of the same samples. This study shows that the aeolian component cannot be assumed to be in isotopic equilibrium and needs to be considered when calculating weathering and erosion timescales.

  1. Comparison of new geochemical proxies in a stalagmite from sub tropical Mexico

    Science.gov (United States)

    Ernesto, H.; Bernal, J.; Lounejeva, E.; McCulloch, M.; Morales, P.; Cienfuegos, E.

    2007-05-01

    The mexican subtropics represent an interesting area to understand past climate change and variability since it is located within the current northern limit of the Inter Tropical Convergence Zone(ITCZ). Consequently, the area is very sensitive to changes in the average position of the ITCZ. We have collected a 33cm stalagmite from Cuetzalan, Pue. Mex (20°00'N, 97°32'W), that grew between 24.08 to 22.35 ky B.P. The stalagmite was analyzed for Sr/Ca, Ba/Ca, Mg/Ca, U/Ca molar ratios, δ13C, δ18O, [234U/238U], and other trace elements, and represents the first stalagmite record from tropical Mexico. Significant variations in the [234U/238U] in the stalagmite, suggest changes in the local weathering rates that are not reflected in other geochemical proxies. However, comparison of the E/Ca and δ18O with records from Hulu (China) and Botuvera (Brazil) caves suggest that the climate in the area was in line with the global climate system.

  2. Migration behavior of naturally occurring radionuclides at the Nopal I uranium deposit, Chihuahua, Mexico

    Science.gov (United States)

    Prikryl, James D.; Pickett, David A.; Murphy, William M.; Pearcy, English C.

    1997-04-01

    Oxidation of pyrite at the Nopal I uranium deposit, Peña Blanca district, Chihuahua, Mexico has resulted in the formation of Fe-oxides/hydroxides. Anomalous U concentrations (i.e. several hundred to several thousand ppm) measured in goethite, hematite, and amorphous Fe-oxyhydroxides in a major fracture that crosscuts the deposit and the absence of U minerals in the fracture suggest that U was retained during secondary mineral growth or sorbed on mineral surfaces. Mobilization and transport of U away from the deposit is suggested by decreasing U concentrations in fracture-infilling materials and in goethite and hematite with distance from the deposit. Greater than unity {234U}/{238U} activity ratios measured in fracture-infilling materials indicate relatively recent ( < 1 Ma) U uptake from fluids that carried excess 234U. Systematic decreases in {234U}/{238U} activity ratios of fracture materials with distance from the deposit suggest a multistage mobilization process, such as remobilization of U from 234U-enriched infill minerals or differential or diminished transport of U-bearing solutions containing excess 234U.

  3. Results of The Excreta Bioassay Quality Control Program For April 1, 2010 Through March 31, 2011

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Cheryl L.

    2012-07-19

    A total of 76 urine samples and 10 spiked fecal samples were submitted during the report period (April 1, 2010 through March 31, 2011) to GEL Laboratories, LLC in South Carolina by the Hanford Internal Dosimetry Program (IDP) to check the accuracy, precision, and detection levels of their analyses. Urine analyses for 14C, Sr, for 238Pu, 239Pu, 241Am, 243Am, 235U, 238U, 238U-mass and fecal analyses for 241Am, 238Pu and 239Pu were tested this year. The number of QC urine samples submitted during the report period represented 1.1% of the total samples submitted. In addition to the samples provided by IDP, GEL was also required to conduct their own QC program, and submit the results of analyses to IDP. About 31% of the analyses processed by GEL during the first year of contract 112512 were quality control samples. GEL tested the performance of 23 radioisotopes, all of which met or exceeded the specifications in the Statement of Work within statistical uncertainty except the slightly elevated relative bias for 243,244Cm (Table 4).

  4. Non-destructive determination of uranium, thorium and 40K in tobacco and their implication on radiation dose levels to the human body.

    Science.gov (United States)

    Landsberger, S; Lara, R; Landsberger, S G

    2015-11-01

    The naturally occurring radionuclides of (235)U, (238)U and (232)Th and their daughter products are a potential major source of anthropogenic radiation to tobacco smokers. Often overlooked is the presence of (40)K in tobacco and its implication to radiation dose accumulation in the human body. In this study, these three radiation sources have been determined in four typical US cigarettes using neutron activation analysis (NAA). The NAA reactions of (238)U(n,γ)(239)U, (232)Th(n,γ)(233)Th and (41)K(n,γ)(42)K were used to determine (235)U, (238)U and (232)Th and (40)K, respectively. The activity of (238)U can easily be determined by epithermal NAA of the (238)U(n,γ)(239)U reaction, and the activity of (235, 234)U can easily be deduced. Using isotopic ratios, the activity due to (40)K was found by the determined concentrations of (41)K (also by epithermal neutrons) in the bulk material. Each gram of total potassium yields 30 Bq of (40)K. The annual effective dose for smokers using 20 cigarettes per day was calculate to be 14.6, 137 and 9 μSv y(-1) for (238,235,) (234)U, (232)Th and (40)K, respectively. These values are significantly lower that the dose received from (210)Po except for (232)Th. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Uranium-Series Disequilibria in the Groundwater of the Shihongtan Sandstone-Hosted Uranium Deposit, NW China

    Directory of Open Access Journals (Sweden)

    Xinjian Peng

    2015-12-01

    Full Text Available Uranium (U concentration and the activities of 238U, 234U, and 230Th were determined for groundwaters, spring waters, and lake water collected from the Shihongtan sandstone-hosted U ore district and in the surrounding area, NW China. The results show that the groundwaters from the oxidizing aquifer with high dissolved oxygen concentration (O2 and oxidation-reduction potential (Eh are enriched in U. The high U concentration of groundwaters may be due to the interaction between these oxidizing groundwaters and U ore bodies, which would result in U that is not in secular equilibrium. Uranium is re-precipitated as uraninite on weathered surfaces and organic material, forming localized ore bodies in the sandstone-hosted aquifer. The 234U/238U, 230Th/234U, and 230Th/238U activity ratios (ARs for most water samples show obvious deviations from secular equilibrium (0.27–2.86, indicating the presence of water-rock/ore interactions during the last 1.7 Ma and probably longer. The 234U/238U AR generally increases with decreasing U concentrations in the groundwaters, suggesting that mixing of two water sources may occur in the aquifer. This is consistent with the fact that most of the U ore bodies in the deposit have a tabular shape originati from mixing between a relatively saline fluid and a more rapidly flowing U-bearing meteoric water.

  6. Plutonium, 137Cs and uranium isotopes in Mongolian surface soils.

    Science.gov (United States)

    Hirose, K; Kikawada, Y; Igarashi, Y; Fujiwara, H; Jugder, D; Matsumoto, Y; Oi, T; Nomura, M

    2017-01-01

    Plutonium (238Pu and 239,240Pu), 137Cs and plutonium activity ratios (238Pu/239,240Pu) as did uranium isotope ratio (235U/238U) were measured in surface soil samples collected in southeast Mongolia. The 239,240Pu and 137Cs concentrations in Mongolian surface soils (<53 μm of particle size) ranged from 0.42 ± 0.03 to 3.53 ± 0.09 mBq g-1 and from 11.6 ± 0.7 to 102 ± 1 mBq g-1, respectively. The 238Pu/239,240Pu activity ratios in the surface soils (0.013-0.06) coincided with that of global fallout. The 235U/238U atom ratios in the surface soil show the natural one. There was a good correlation between the 239,240Pu and 137Cs concentrations in the surface soils. We introduce the migration depth to have better understanding of migration behaviors of anthropogenic radionuclides in surface soil. We found a difference of the migration behavior between 239,240Pu and 137Cs from 137Cs/239,240Pu - 137Cs plots for the Mongolian and Tsukuba surface soils; plutonium in surface soil is migrated easier than 137Cs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Uranium ((234)U, (235)U and (238)U) contamination of the environment surrounding phosphogypsum waste heap in Wiślinka (northern Poland).

    Science.gov (United States)

    Olszewski, Grzegorz; Boryło, Alicja; Skwarzec, Bogdan

    2015-08-01

    The aim of this work was to determine the uranium concentration ((234)U, (235)U and (238)U) and values of the activity ratio (234)U/(238)U in soil samples collected near phosphogypsum waste heap in Wiślinka (northern Poland). On the basis of the studies it was found that the values of the (234)U/(238)U activity ratio in the analyzed soils collected in the vicinity of phosphogypsum dump in Wiślinka are in most cases close to one and indicate the phosphogypsum origin of the analyzed nuclides. The obtained results of uranium concentrations are however much lower than in previous years before closing of the phosphogypsum stockpile. After this process and covering the phosphogypsum stockpile in Wiślinka with sewage sludge, phosphogypsum particles are successfully immobilized. In the light of the results the use of phosphate fertilizers seems to be a major problem. Prolonged and heavy rains can cause leaching accumulated uranium isotopes in the phosphogypsum stockpile, which will be washed into the Martwa Wisła and on the fields in the immediate vicinity of this storage. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Measurement of uranium and its isotopes at trace levels in environmental samples using mass spectrometry

    Science.gov (United States)

    Sahoo, S. K.

    2009-06-01

    Actinides have widely entered the environment as a result of nuclear accidents and atmospheric weapon testing. These radionuclides, especially uranium, are outstanding radioactive pollutants, due to their high radiotoxicity and long half-lives. In addition to this, since depleted uranium (DU) has been used in the Balkan conflict in 1999, there has been a concern about the possible consequences of its use for the people and environment. Therefore, accurate, precise and simple determination methods are necessary in order to evaluate the human dose and the concentration and effects of these nuclides in the environment. The principal isotopes of uranium e.g. 235U and 238U are of primordial origin and 234U present in radioactive equilibrium with 238U. 236U occurs in nature at ultra trace concentrations with a 236U: 238U atom ratio of 10-14. Concentrations of uranium in soil samples were determined using inductively coupled plasma mass spectrometry (ICP-MS) and isotope ratios of uranium were measured using a thermal ionisation mass spectrometer. Radioactive dis-equilibrium of 234/238U, depletion of 235/238U and significant evidence of 236U/238U were noticed in soil samples.

  9. Practical resolution of angle dependency of multigroup resonance cross sections using parametrized spectral superhomogenization factors

    Directory of Open Access Journals (Sweden)

    Hansol Park

    2017-09-01

    Full Text Available Based on the observation that ignoring the angle dependency of multigroup resonance cross sections within a fuel pellet would result in nontrivial underestimation of the spatial self-shielding of flux, a parametrized spectral superhomogenization (SPH factor library (PSSL method is developed as a practical means of resolving the problem. Region-wise spectral SPH factors are calculated by the normal and transport corrected SPH iterations after ultrafine group slowing down calculations over various light water reactor pin-cell configurations. The parametrization is done with fuel temperature, U-238 number density, fuel radius, moderator source represented by ΣmodVmod, and the number density ratio of resonance nuclides to that of U-238 in a form of resonance interference correction factors. The parametrization is successful in that the root mean square errors of the interpolated SPH factors over the fuel regions of various pin-cells are within 0.1%. The improvement in reactivity error of the PSSL method is shown to be superior to that by the original SPH method in that the reactivity bias of −200 pcm to −300 pcm vanishes almost completely. It is demonstrated that the environment effect takes only about 4% in the reactivity improvement so that the pin-cell based PSSL method is effective in the assembly problems.

  10. Kajian Sebaran Radioaktif Gamma dalam Lingkungan Airtanah di Sisi Selatan Gunungapi Merapi, Desa Wukirsari, Kecamatan Cangkringan, Kabupaten Sleman

    Directory of Open Access Journals (Sweden)

    Andreas R. P. Lakafi

    2016-10-01

    Full Text Available ABSTRAK Penelitian ini dilakukan di Desa Wukirsari Kecamatan Cangkringan Kabupaten Sleman. Radioaktif alam adalah radioaktif yang berasal dari radiasi yang ada di bumi. Radionuklida alam penyumbang terbesar terhadap besarnya paparan gamma ke manusia adalah anak luruh Uranium-238 (U-238. Radionuklida tersebut akan sangat berbahaya bagi manusia jika mencemari airtanah yang akan digunakan manusia.  Penelitian ini bertujuan untuk mengkaji persebaran radioaktivitas gamma dalam airtanah bebasdi daerah penelitianakibat erupsi Gunungapi Merapi 2010 dan merumuskan upaya strategik pengelolaan lingkungan untuk menangani permasalahan potensi terkontaminasinya airtanah oleh radioaktif. Penelitian ini menggunakan metode survey.Metode sistematik berdasarkan grid untuk menentukan titik sampel dan pola aliran airtanah. Untuk memperoleh data kualitas airtanah menggunakan metode purposif dengan mempertimbangkan titik sampel yang diambil harus berada pada satu jalur aliran airtanah yang ditunjukkan dalam pola aliran airtanah. Data yang diperoleh berupa data aktivitas radioaktif dan dosis efektif. Tujuan kedua dicapai dengan metode deskriptif kualitatif dengan menggunakan data sebaran dosis efektif sebagai acuan alternatif strategi pengelolaan lingkungan yang diberikan. Hasil penelitian menunjukkan bahwa, aktivitas radioaktif gamma U-238 pada airtanah dilokasi penelitian masih aman karena masih di bawah baku mutu berdasarkan Keputusan Kepala Badan Pengawas Tenaga Nuklir nomor: 02/Ka-BAPETEN/V-99 tentang baku tingkat radioaktivitas lingkungan yaitu 1x103 Bq/liter untuk syarat aktivitas U-238 di air. Dari hasil pengujian didapati bahwa, aktivitas U-238 rentang  yaitu 0,123±0,04 Bq/liter sampai 0,283±0,011 Bq/liter. Untuk dosis efektif didapati bahwa sebaran dosis efektif di daerah penelitian juga masih sangat rendah dan aman yaitu berada pada 4,00 µSv/tahun hingga 8,14 µSv/tahun. Dosis efektif di daerah penelitian masih jauh di bawah batas ambang yang ditentukan

  11. Rate equation model of laser induced bias in uranium isotope ratios measured by resonance ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Isselhardt, B. H.; Prussin, S. G.; Savina, M. R.; Willingham, D. G.; Knight, K. B.; Hutcheon, I. D.

    2016-01-01

    Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process between uranium atoms and potential isobars without the aid of chemical purification and separation. The use of broad bandwidth lasers with automated feedback control of wavelength was applied to the measurement of the U-235/U-238 ratio to decrease laser-induced isotopic fractionation. In application, isotope standards are used to identify and correct bias in measured isotope ratios, but understanding laser-induced bias from first-principles can improve the precision and accuracy of experimental measurements. A rate equation model for predicting the relative ionization probability has been developed to study the effect of variations in laser parameters on the measured isotope ratio. The model uses atomic data and empirical descriptions of laser performance to estimate the laser-induced bias expected in experimental measurements of the U-235/U-238 ratio. Empirical corrections are also included to account for ionization processes that are difficult to calculate from first principles with the available atomic data. Development of this model has highlighted several important considerations for properly interpreting experimental results.

  12. IAEA-447: a new certified reference material for environmental radioactivity measurements.

    Science.gov (United States)

    Shakhashiro, A; Tarjan, S; Ceccatelli, A; Kis-Benedek, G; Betti, M

    2012-08-01

    The environment program of the International Atomic Energy Agency (IAEA) includes activities to produce and certify reference materials for environmental radioactivity measurements. This paper describes methodologies applied in preparation and certification of the new IAEA-447 moss-soil certified reference material. In this work, the massic activities and associated standard uncertainties of (40)K, (90)Sr, (137)Cs, (208)Tl, (210)Pb, (210)Po, (212)Pb, (214)Pb, (214)Bi, (226)Ra, (228)Ac, (234)Th, (234)U, (238)U, (238)Pu, (239+240)Pu, (241)Pu and (241)Am were established. Details of the analytical methods including radiochemical procedures were reported. Analytical challenges and lessons learned from the reported results in the worldwide IAEA proficiency test using this material was summarized and best analytical practices to improve the performance for environmental radioactivity determinations were recommended. IAEA-447 is an important reference material for quality control and method validation of gamma-ray spectrometry and radiochemical analytical procedures. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Nationwide occurrence of radon and other natural radioactivity in public water supplies

    Energy Technology Data Exchange (ETDEWEB)

    Horton, T. R.

    1985-10-01

    The nationwide study, which began in November of 1980, was designed to systematically sample water supplies in all 48 contiguous states. The results of the study will be used, in cooperation with EPA's Office of Drinking Water, to estimate population exposures nationwide and to support possible future standards for radon, uranium, and other natural radioactivity in public water supplies. Samples from more than 2500 public water supplies representing 35 states were collected. Although we sampled only about five percent of the total number of groundwater supplies in the 48 contiguous states of the US, those samples represent nearly 45 percent of the water consumed by US groundwater users in the 48 contiguous states. Sample results are summarized by arithmetic mean, geometric mean, and population weighted arithmetic mean for each state and the entire US. Results include radon, gross alpha, gross beta, Ra-226, Ra-228, total Ra, U-234, U-238, total U, and U-234/U-238 ratios. Individual public water supply results are found in the appendices. 24 refs., 91 figs., 51 tabs.

  14. Experimental investigation of uranium-series isotope mobility in a basaltic weathering profile

    Science.gov (United States)

    Dosseto, Anthony; Menozzi, Davide; Kinsley, Leslie

    2015-04-01

    The measurement of uranium (U)-series isotopes in regolith can be used to determine the formation rate of weathering profiles. This approach aims at following how the U-series isotope composition of primary minerals (i.e. those derived from the parent material) vary during the development of the weathering profile. Nevertheless, regolith samples are a complex mixture of primary minerals, secondary minerals that are the residue of primary mineral weathering, secondary minerals that precipitate from pore water, minerals derived from atmospheric deposition and organic matter. In this study, firstly we aim at isolating primary minerals and the secondary minerals derived from them, by evaluating a sequential extraction procedure designed to eliminate carbonates, Fe-Mn oxides and organic matter. Secondly, we investigate the behaviour of U-series isotopes during primary mineral dissolution by applying a mild HF/HCl etching solution to the residues of the sequential extraction. These experiments were performed on bedrock, saprolite and soil derived from a basaltic weathering profile in south-eastern Australia. Results show that up to 50% of U is removed during sequential extraction, suggesting that (i) there is a large pool of labile U in the bedrock and (ii) secondary phases and organic matter account for a large fraction of the U budget in bulk saprolite and soil. Sequential extraction has little impact on the (234U/238U) activity ratio of bedrock and saprolite, whilst it shows a decrease in soil. This suggests that the pool of U removed from bedrock and saprolite has a (234U/238U) similar to that of primary minerals; but in the soil, the U removed (mostly from organic matter) is enriched in 234U. This is expected as organic matter uptakes U from pore solutions, which are generally enriched in 234U. During HF/HCl etching, the (234U/238U) of bedrock and saprolite is greater than 1. Sheng and Kuroda [1] previously proposed that (234U/238U) >1 in rocks could be explained by

  15. Measuring and predicting the transport of actinides and fission product contaminants in unsaturated prairie soil

    Science.gov (United States)

    Sims, D. J.

    Soil samples have been taken in 2001 from the area of a 1951 release from an underground storage tank of 6.7 L of an aqueous solution of irradiated uranium (360 GBq). A simulation of the dispersion of the actinides and fission products was conducted in the laboratory using irradiated natural uranium, non-irradiated natural uranium and metal standards dissolved in acidic aqueous solutions and added to soil columns containing uncontaminated prairie soil. The lab soil columns were allowed 12 to 14 months for contaminant transport. Soil samples were analyzed using gamma-ray spectroscopy, neutron activation analysis (NAA) and liquid scintillation counting (LSC) to determine the elemental concentrations of U, Cs and Sr. Diffusion coefficients from the 50 year soil samples and the lab soil samples were determined. The measured diffusion coefficients from the field samples were 3.0 x 10-4 cm2 s-1 (Cs-137), 1.8 x 10-5 cm2 s-1 (U-238) and 2.6 x 10-3 cm2 s-1 (Sr-90) and the values determined from lab simulation were 5 x 10-6 cm 2 s-1 (Cs-137), 3 x 10-5 cm2 s-1 (U-238) and 1.9 x 10-5 cm 2 s-1 (Sr-90). The differences between the sets of diffusion coefficients can be attributed to differences in retardation effects, weather effects and changes in the soil characteristics when transporting, such as porosity. The analytical work showed that Cs-137 content of soil can be determined effectively using gamma-ray spectroscopy; U-238 content can be measured using NAA; and Sr-90 content can be measured using LSC. For non- and low-radioactive species, it was shown that both flame atomic absorption spectrometry (FAAS) and inductively-coupled plasma-mass spectrometry (ICP-MS) gave comparable results for Sr, Cs and Sm, with the average values ranging from 0.5 to 4.5 ppm of each other. The U-238 content results from NAA and from ICP-MS showed general agreement with an average difference of 81.3 ppm on samples having concentrations up to 988.2 ppm. The difference may have been due to matrix

  16. Permafrost thaw in upland catchments of central Alaska: groundwater connection and landscape evolution as discerned from U isotopes and dissolved organic carbon

    Science.gov (United States)

    Ewing, S. A.; O'Donnell, J. A.; Paces, J. B.; Jorgenson, M. T.; Kanevskiy, M. Z.; Harden, J. W.; Aiken, G.; Striegl, R. G.

    2009-12-01

    Permafrost thaw mobilizes carbon and transforms hydrologic flowpaths, with the potential for large feedback effects on climate. Permafrost thaw also results in poorly quantified geomorphic effects that depend on ground ice volumes, sediment texture, and thermal effects of thaw waters. Here we use 234U/238U activity ratios (ARs) to indicate the influence of deep groundwater following fire-induced permafrost thaw in geologically distinct upland catchments in central Alaska. The 234U/238U AR in water or ice increases as a function of contact time with sediment, at a rate that depends on sediment and water U concentrations, surface area, and sediment/water ratio. Combining U series data with solute concentrations for soil porewaters, shallow permafrost and surface streams, we make inferences about the influence of recent thaw (last 100 y) on landscapes, hydrology and dissolved organic carbon (DOC) dynamics in central Alaska. In a loess-dominated catchment where ice-rich silt is present to depths of up to 25 m, the depth of fire-induced thaw is limited to ~50 cm. DOC concentrations in surface waters and soil porewaters showed little seasonal or spatial variation (40±7 ppm in spring and fall 2008) and were positively correlated with solutes indicating mineral contact in fall 2008. In soil porewaters, surface waters and upper permafrost (2 m depth), 234U/238U ARs (1.15-1.27) were lower than those in deep permafrost (up to 1.55) and groundwater (1.54), suggesting no deep thaw or connection to deeper groundwater regardless of time-since-fire. Shallow thaw and soil wetting allowed for post-fire recovery of shallow permafrost and hence black spruce communities on the order of 100 y. Yet we observed landscape responses to thaw including thermokarst pits and channels, bank collapse, and stream incision, suggesting longer-term landscape equilibration. By contrast, in a colluvium-dominated catchment, gravelly textures allow better drainage of thaw water, resulting in deep thaw

  17. Characterization Investigation Study: Volume 3, Radiological survey of surface soils

    Energy Technology Data Exchange (ETDEWEB)

    Solow, A.J.; Phoenix, D.R.

    1987-12-01

    The Feed Materials Production Center was constructed to produce high purity uranium metal for use at various Department of Energy facilities. The waste products from these operations include general uncontaminated scrap and refuse, contaminated and uncontaminated metal scrap, waste oils, low-level radioactive waste, co-contaminated wastes, mixed waste, toxic waste, sludges from water treatment, and fly ash from the steam plant. This material is estimated to total more than 350,000 cubic meters. Other wastes stored in this area include laboratory chemicals and other combustible materials in the burn pit; fine waste stream sediments in the clear well; fly ash and waste oils in the two fly ash areas; lime-alum sludges and boiler plant blowdown in the lime sludge ponds; and nonradioactive sanitary waste, construction rubble, and asbestos in the sanitary landfill. A systematic survey of the surface soils throughout the Waste Storage Area, associated on-site drainages, and the fly ash piles was conducted using a Field Instrument for Detecting Low-Energy Radiation (FIDLER). Uranium is the most prevalent radioactive element in surface soil; U-238 is the principal radionuclide, ranging from 2.2 to 1790 pCi/g in the general Waste Storage Area. The maximum values for the next highest activity concentrations in the same area were 972 pCi/g for Th-230 and 298 pCi/g for U-234. Elevated activity concentrations of Th-230 were found along the K-65 slurry line, the maximum at 3010 pCi/g. U-238 had the highest value of 761 pCi/g in the drainage just south of pit no. 5. The upper fly ash area had the highest radionuclide activity concentrations in the surface soils with the maximum values for U-238 at 8600 pCi/g, U-235 at 2190 pCi/g, U-234 at 11,400 pCi/g, Tc-99 at 594 pCi/g, Ra-226 at 279 pCi/g, and Th-230 at 164 pCi/g.

  18. Tracing the Sources and History of Subsurface Contamination at the Hanford Site in Washington Using High-Precision Uranium Isotopic Measurements

    Science.gov (United States)

    Christensen, J. N.; Dresel, P. E.; Conrad, M. E.; Maher, K.; Depaolo, D. J.

    2003-12-01

    Groundwater contamination at the Hanford Site, Washington, resulted from decades of nuclear fuel production and processing. Understanding the fate and transport of contaminants has been complicated by the presence of multiple potential sources within relatively small areas. The contrasts in isotopic composition between natural and anthropogenic uranium promotes the measurement of uranium isotopic composition as a fingerprint and tracer of uranium contamination in the environment. In this study we focused on a uranium groundwater plume and two vadose zone U plumes associated with the B-BX-BY waste management area, used since the late 1940's for the storage of high-level radioactive waste. Groundwater U contamination was first detected in monitoring wells in the early 1990's. The groundwater plume (>30 ppb U) is currently approximately 250 m wide, at least 900 m long with U concentrations up to 525 ppb. The exact origin and history of this contamination is not well understood, since a number of tanks and incidents are potential sources. Using multiple collector ICPMS (Micromass IsoProbe) high precision uranium isotopic analyses were conducted of samples of vadose zone contamination and of groundwater. The measured isotopic compositions (234U/238U, 235U/238U and 236U/238U) are used to distinguish contaminant sources, and are compared to a history of processed U fuel rod compositions. Based on the isotopic data, the groundwater plume appears to be related to a tank overflow event in 1951 that spilled high-level waste into the vadose zone. A second zone of identified vadose zone contamination does not seem to be an important contributor to the groundwater U plume. The variation in U isotopic composition of the groundwater samples is a result of mixing of contaminant U from the 1951 event and natural background U. The identified vadose zone contamination source is horizontally displaced from the initial locus of groundwater contamination, indicating that lateral

  19. Preliminary studies of groundwater flow and migration of uranium isotopes around the Oklo natural reactors (Gabon)

    Science.gov (United States)

    Toulhoat, Pierre; Gallien, Jean Paul; Louvat, Didier; Moulin, Valérie; l'Henoret, Pascal; Guérin, Roland; Ledoux, Emmanuel; Gurban, Ioana; Smellie, John A. T.; Winberg, Anders

    1996-02-01

    In specific zones of the Oklo uranium deposit, critically was naturally reached 2 Ga ago. This site thus provides a unique opportunity to show whether the stable nuclear reaction end-products have remained or not in the vicinity of the reactor zones after the termination of nuclear reactions. In addition, the evaluation of the stability of the uraninite matrix over very long periods of time provides information on the possible long-term stability of waste forms such as spent fuel. The Commission of the European Communities initiated in 1991 the Oklo Natural Analogue Programme, a part of which is devoted to present-day migration studies. The Swedish Nuclear Fuel and Waste Management Company (SKB) supports this programme, with special interest in the Bangombe reactor, a shallow reaction zone possibly affected by surficial alteration processes. The Oklo study comprises hydrogeology, groundwater chemistry, isotopic analyses (environmental isotopes, U series, 235U/ 238U), and modelling. Two sites are being thoroughly investigated: the less perturbed OK84 reactor zone in Okelobondo (200 m south from Oklo) and the Bangombe reactor zone, 30 km south of Oklo. We focus our study on uranium migration from these reactor zones, using tracers such as the 235U/ 238U isotope ratio. After preliminary field campaigns, a conceptual model was constructed, both for Okelobondo and Bangombe. For this purpose, groundwaters have been characterised for three years in different areas around Oklo: Okelobondo groundwaters in mines and boreholes and surface waters, and Bangombe, both in boreholes and surface waters. Detailed investigations were then conducted in order to validate our conceptual models, and finally to enabling us to model U migration from the reaction zones, and to evaluate the performance assessment of deep geological disposal of radioactive wastes. After the presentation of regional and local geology and hydrogeology, we give a complete description and interpretation of

  20. 2003 Initial Assessments of Closure for the C Tank Farm Field Investigation Report (FIR):Numerical Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.; Freedman, Vicky L.; White, Mark D.

    2003-07-15

    In support of CH2M HILL Hanford Group, Inc.'s (CHG) preparation of a Field Investigative Report (FIR) for the closure of the Hanford Site Single-Shell Tank (SST) Waste Management Area (WMA) tank farms, a set of numerical simulations of flow and solute transport was executed to predict the performance of surface barriers for reducing long-term risks from potential groundwater contamination at the C Farm WMA. This report documents the simulation of 14 cases (and two verification cases) involving two-dimensional cross sections through the C Farm WMA tanks C-103 – C-112. Utilizing a unit release scenario at Tank C-112, four different types of leaks were simulated. These simulations assessed the impact of leakage during retrieval, past leaks, and tank residual wastes and tank ancillary equipment following closure activities. . Two transported solutes were considered: uranium-238 (U-238) and technetium-99 (Tc-99). To evaluate the impact of sorption to the subsurface materials, six different retardation coefficients were simulated for U-238. Overall, simulations results for the C Farm WMA showed that only a small fraction of the U-238 with retardation factors greater than 0.6 migrated from the vadose zone in all of the cases. For the conservative solute, Tc-99, results showed that the simulations investigating leakages during retrieval demonstrated the highest WMA peak concentrations and the earliest arrival times due to the high infiltration rate before the use of surface barriers and the addition of water into the system. Simulations investigating past leaks showed similar peaks and arrival times as the retrieval leak cases. Several different release rates were used to investigate contaminant transport from residual tank wastes. All showed similar peak concentrations and arrival times, except for the lowest initial release rate, which was 1,000 times slower than the highest release rate. Past leaks were also investigated with different release rate models

  1. Estimation of uranium migration parameters in sandstone aquifers.

    Science.gov (United States)

    Malov, A I

    2016-03-01

    The chemical composition and isotopes of carbon and uranium were investigated in groundwater samples that were collected from 16 wells and 2 sources in the Northern Dvina Basin, Northwest Russia. Across the dataset, the temperatures in the groundwater ranged from 3.6 to 6.9 °C, the pH ranged from 7.6 to 9.0, the Eh ranged from -137 to +128 mV, the total dissolved solids (TDS) ranged from 209 to 22,000 mg L(-1), and the dissolved oxygen (DO) ranged from 0 to 9.9 ppm. The (14)C activity ranged from 0 to 69.96 ± 0.69 percent modern carbon (pmC). The uranium content in the groundwater ranged from 0.006 to 16 ppb, and the (234)U:(238)U activity ratio ranged from 1.35 ± 0.21 to 8.61 ± 1.35. The uranium concentration and (234)U:(238)U activity ratio increased from the recharge area to the redox barrier; behind the barrier, the uranium content is minimal. The results were systematized by creating a conceptual model of the Northern Dvina Basin's hydrogeological system. The use of uranium isotope dating in conjunction with radiocarbon dating allowed the determination of important water-rock interaction parameters, such as the dissolution rate:recoil loss factor ratio Rd:p (a(-1)) and the uranium retardation factor:recoil loss factor ratio R:p in the aquifer. The (14)C age of the water was estimated to be between modern and >35,000 years. The (234)U-(238)U age of the water was estimated to be between 260 and 582,000 years. The Rd:p ratio decreases with increasing groundwater residence time in the aquifer from n × 10(-5) to n × 10(-7) a(-1). This finding is observed because the TDS increases in that direction from 0.2 to 9 g L(-1), and accordingly, the mineral saturation indices increase. Relatively high values of R:p (200-1000) characterize aquifers in sandy-clayey sediments from the Late Pleistocene and the deepest parts of the Vendian strata. In samples from the sandstones of the upper part of the Vendian strata, the R:p value is ∼ 24, i.e., sorption processes are

  2. Characterization of DWPF recycle condensate materials

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Adamson, D. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); King, W. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-04-01

    A Defense Waste Processing Facility (DWPF) Recycle Condensate Tank (RCT) sample was delivered to the Savannah River National Laboratory (SRNL) for characterization with particular interest in the concentration of I-129, U-233, U-235, total U, and total Pu. Since a portion of Salt Batch 8 will contain DWPF recycle materials, the concentration of I-129 is important to understand for salt batch planning purposes. The chemical and physical characterizations are also needed as input to the interpretation of future work aimed at determining the propensity of the RCT material to foam, and methods to remediate any foaming potential. According to DWPF the Tank Farm 2H evaporator has experienced foaming while processing DWPF recycle materials. The characterization work on the RCT samples has been completed and is reported here.

  3. Split-core heat-pipe reactors for out-of-pile thermionic power systems.

    Science.gov (United States)

    Niederauer, G.; Lantz, E.; Breitweiser, R.

    1971-01-01

    Description of the concept of splitting a heat-pipe reactor for out-of-core thermionics into two identical halves and using the resulting center gap for reactivity control. Short Li-W reactor heat pipes penetrate the axial reflectors and form a heat exchanger with long heat pipes which wind through the shield to the thermionic diodes. With one reactor half anchored to the shield, the other is attached to a long arm with a pivot behind the shield and swings through a small arc for reactivity control. A safety shim prevents large reactivity inputs, and a fueled control arm drive shaft acts as a power stabilizer. Reactors fueled with U-235C and with U-233C have been studied.-

  4. Assessment of alternatives for management of ORNL retrievable transuranic waste. Nuclear Waste Program: transuranic waste (Activity No. AR 05 15 15 0; ONL-WT04)

    Energy Technology Data Exchange (ETDEWEB)

    1980-10-01

    Since 1970, solid waste with TRU or U-233 contamination in excess of 10 ..mu..Ci per kilogram of waste has been stored in a retrievable fashion at ORNL, such as in ss drums, concrete casks, and ss-lined wells. This report describes the results of a study performed to identify and evaluate alternatives for management of this waste and of the additional waste projected to be stored through 1995. The study was limited to consideration of the following basic strategies: Strategy 1: Leave waste in place as is; Strategy 2: Improve waste confinement; and Strategy 3: Retrieve waste and process for shipment to a Federal repository. Seven alternatives were identified and evaluated, one each for Strategies 1 and 2 and five for Strategy 3. Each alternative was evaluated from the standpoint of technical feasibility, cost, radiological risk and impact, regulatory factors and nonradiological environmental impact.

  5. Thorium as a Fuel for Accelerator Driven Subcritical Electronuclear Systems

    CERN Document Server

    Barashenkov, V S; Singh, V

    2000-01-01

    Neutron yield and energy production in a very large, practically infinite, uranium and thorium target-blocks irradiated by protons with energies in the range 0.1-2 GeV are studied by Monte Carlo method. Though the comparison of uranium and thorium targets shows that the neutron yield in the latter is 30-40 % less and the energy gain is approximatelly two times smaller, accelerator Driven subcritical Systems (ADS) with thorium fuel are very perspective at the bombarding energies higher than several hundreds MeV. An admixture of fissile elements U^{233}, U^{235}, Pu^{239} in the set-up gives larger neutron multiplication which in turn shows better energy amplification. It is argued that due to the practically complete burning of the fuel in such set-up there is no need of technology of conversion of the exhaust fuel.

  6. REDUPP First Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Zetterstrom Evins, L. [Svensk Kaernbraenslehantering AB (SKB), Stockholm (Sweden); Vahanen, M. (eds.)

    2012-06-15

    The REDUPP project aims to investigate how surfaces of solids with a fluorite structure change with time during dissolution. Laboratory experiments are performed to monitor dissolution of CaF{sub 2}, CeO{sub 2}, ThO{sub 2} and UO{sub 2}, in connection with ab initio calculations. Another aspect of the project involves investigating if using natural groundwater in the leaching tests has an effect on the measured dissolution rate of UO{sub 2}. The preliminary results after one project year are documented here. Samples have been prepared as sintered pellets with similar microstructures as UO{sub 2}. For the UO{sub 2} study, pellets doped with U-233 are used. Preliminary dissolution data show the expected trends for pH and temperature dissolution kinetics dependence. Studies on CeO{sub 2} monolith samples indicate that there is a crystallographic control on leaching, and that the grain boundaries are preferentially attacked. Measurable Th concentrations are achieved in pre-tests for ThO{sub 2} dissolution where the effect of carbonate complexation is also observed. The preliminary results of the studies performed on U-233-doped UO{sub 2} samples in natural groundwater are in agreement with previous results, and show no observable effect of trace elements or level of alpha radiolysis. In the modelling work, the stabilities of surfaces corresponding to different crystal planes have been computed, and work is in progress to develop a model involving stepped surfaces. Preliminary results show that only a few energies of reference planes need to be computed, and all other surface energies can be accurately estimated from a linear relation. The goal is to develop a model of how the surfaces of fluorite-structures evolve during dissolution. (orig.)

  7. Advanced fuel cycles for use in PHWRs

    Science.gov (United States)

    Gupta, H. P.; Menon, S. V. G.; Banerjee, S.

    2008-12-01

    Pressurized heavy water reactors (PHWRs) were originally designed for employing once through fuel cycles with natural uranium. The excellent neutron economy and on-line fueling due to limited excess reactivity are important characteristics of these reactors. However, PHWRs have the main drawback of low burn-up, approximately 7500 MWd/T, due to the use of natural uranium. Use of neutron absorbers for control and power flattening further deteriorates the burn-up. All these aspects, specific to PHWRs, also lead to management of large quantities of: (i) initial fuel (ii) irradiated fuel, and (iii) radioactive wastes. Some of these drawbacks can be alleviated with high burn-up fuel, which also improves fuel utilization. Slightly enriched uranium and plutonium have been under consideration for this purpose. In situ production of U 233, by using thorium along with appropriate fissile feed, is one possibility. Alternatively, U 233 can be generated externally in fast breeder reactors. It has been recognized that, when used along with thorium, PHWRs can also serve as efficient burners of excess plutonium accumulated over the years. Fuel cycles have been designed so as to completely reverse the isotopic composition (fissile to fertile ratio) which exists at the beginning of a cycle. These cycles also envisage producing proliferation resistant fuels containing high gamma-active decay products. Most of the reactor physics aspects of the various fuel cycles can be analyzed using simple methods of neutron physics and fuel burn-up. Multi-group techniques and explicit representations of the PHWR cluster geometry are essential. However, core physics and fuel management calculations can be simplified at an exploratory stage. Nevertheless, it is necessary to make sure, using core analyses, that the new fuel cycles do satisfy all the constraints of flux peaking, controllability, coolant void reactivity, etc. The main aim in this paper is to provide a comparative evaluation of the

  8. Characterization of DWPF recycle condensate tank materials

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-01-01

    A Defense Waste Processing Facility (DWPF) Recycle Condensate Tank (RCT) sample was delivered to the Savannah River National Laboratory (SRNL) for characterization with particular interest in the concentration of I-129, U-233, U-235, total U, and total Pu. Since a portion of Salt Batch 8 will contain DWPF recycle materials, the concentration of I-129 is important to undertand for salt batch planning purposes. The chemical and physical characterizations are also needed as input to the interpretation of future work aimed at determining the propensity of the RCT material to foam, and methods to remediate any foaming potential. According to DWPF the Tank Farm 2H evaporator has experienced foaming while processing DWPF recycle materials. The characterization work on the RCT samples has been completed and is reported here. The composition of the Sludge Batch 8 (SB8) RCT material is largely a low base solution of 0.2M NaNO2 and 0.1M NaNO3 with a small amount of formate present. Insoluble solids comprise only 0.05 wt.% of the slurry. The solids appear to be largely sludge-like solids based on elemental composition and SEM-EDS analysis. The sample contains an elevated concentration of I-129 (38x) and substantial 59% fraction of Tc-99, as compared to the incoming SB8 Tank 40 feed material. The Hg concentration is 5x, when compared to Fe, of that expected based on sludge carryover. The total U and Pu concentrations are reduced significantly, 0.536 wt.% TS and 2.42E-03 wt.% TS, respectively, with the fissile components, U-233, U-235, Pu-239, and Pu-241, an order of magnitude lower in concentration than those in the SB8 Tank 40 DWPF feed material. This report will be revised to include the foaming study requested in the TTR and outlined in the TTQAP when that work is concluded.

  9. Assessing and modeling sediment mobility in estuarine and coastal settings due to extreme climate events from natural short-lived isotope distribution

    Science.gov (United States)

    Ghaleb, Bassam; Hillaire-Marcel, Claude; Ruiz Fernandez, Ana-Carolina; Sanchez Cabeza, Joan-Albert

    2016-04-01

    Climatic events (e.g. floods, storminess) and management activities (e.g. dredging) may result in the burial or removal and re-suspension of sediments in estuaries and coastal areas. When such sediments are contaminated, such processes may either help restoring better chemical environments or lead to their long-term contamination. Geochemical signatures in surface sediments may help identifying such sedimentological events. However, short-lived isotope data are generally required to set time-constraints on their occurrence. Whereas 210Pb and radioactive fallout isotope contents can help setting time constraints at ~50 to ~100 yr-time scales, natural disequilibria in the 232Th-228Ra-228Th sequence do provide information on processes which occurred within the last 30 yrs, as illustrated in the present study. Box-cored sediments from the Saguenay Fjord and lower estuary of the St. Lawrence (Canada) as well as from estuaries and lagoons from the Sinaloa Coast (Mexico) are used to document the behavior of these isotopes either under relatively steady conditions (St. Lawrence estuary) or under high-frequency extreme climate events (storms and floods; Saguenay Fjord, Coastal Sinaloa). 228Th/232Th activity ratios were determined by chemical extraction of Th and alpha counting of unspiked samples, rapidly after sampling (228Th/232Th). The activity of the intermediate isotope 228Ra was then estimated based on replicate measurements on aliquot samples made a few years later. Under steady conditions, core-top sediment shows an excess in 228Th vs 232Th (AR ~ 1.6), whereas the intermediate 228Ra depicts a deficit vs its parent 232Th (AR ~0.6). Downcore, radioactive decay carries rapidly 228Th-activities to those of the parent 228Ra within about 10 yrs (i.e., ~ 5 half-lives of 228Th), then both move during the next ~20 yrs (~ i.e., ~ 5 half-lives of 228Ra, when added to the 10 yrs of 228Th-excess) towards secular equilibrium with the parent long-lived 232Th. A few algorithms

  10. Application of multi-way partial least squares calibration for simultaneous determination of radioisotopes by liquid scintillation technique

    Directory of Open Access Journals (Sweden)

    Mahani Mohamad

    2012-01-01

    Full Text Available Three-way partial last squares (3-PLS2, as a multi-way calibration method was applied for determining the 235U/238U isotope ratio to overcome problems with spectral interferences in liquid scintillation spectra of these radioisotopes. The alpha energy spectra of samples in different energy channels and different cocktail to sample ratios were used as input data for 3-PLS2. The model was applied to a prediction set and satisfactory results were obtained. The 3-way PLS2 prediction results were compared with 2-way PLS2 and it was shown that 3-way PLS2 results are more accurate than the results of PLS2. Thermal ionization-mass spectrometry was used as a reference method for calculating the accuracy of our method.

  11. Nondestructive Analysis of MET-5 Paint Can at TA35 Building 2 A-Wing Vault

    Energy Technology Data Exchange (ETDEWEB)

    Desimone, David J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vo, Duc Ta [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-03

    In Building 2 A-wing vault MET-5 has some drums and other packages they wanted NEN-1 help identifying nondestructively. Measurements using a mechanically cooled portable high-purity germanium HPGe Ortec detective were taken of a paint can container labeled DU-2A to determine if any radioactive material was inside. The HPGe detector measures the gamma rays emitted by radioactive material and displays it as a spectrum. The spectrum is used to identify this radioactive material by using appropriate analysis software and identifying the gamma ray peaks. A paint can container, DU-2A, was analyzed with PeakEasy 4.84 and FRAM 5.2. The FRAM report is shown. The enrichment is 0.091% U235 and 99.907% U238. This material is depleted uranium. The measurement was performed in the near field, and to extract a mass a far field measurement will need to be taken.

  12. Role of Multichance Fission in the Description of Fission-Fragment Mass Distributions at High Energies

    Science.gov (United States)

    Hirose, K.; Nishio, K.; Tanaka, S.; Léguillon, R.; Makii, H.; Nishinaka, I.; Orlandi, R.; Tsukada, K.; Smallcombe, J.; Vermeulen, M. J.; Chiba, S.; Aritomo, Y.; Ohtsuki, T.; Nakano, K.; Araki, S.; Watanabe, Y.; Tatsuzawa, R.; Takaki, N.; Tamura, N.; Goto, S.; Tsekhanovich, I.; Andreyev, A. N.

    2017-12-01

    Fission-fragment mass distributions were measured for U 237 - 240 , Np 239 - 242 , and Pu 241 - 244 populated in the excitation-energy range from 10 to 60 MeV by multinucleon transfer channels in the reaction O 18 +U 238 at the Japan Atomic Energy Agency tandem facility. Among them, the data for U 240 and Np 240 ,241 ,242 were observed for the first time. It was found that the mass distributions for all the studied nuclides maintain a double-humped shape up to the highest measured energy in contrast to expectations of predominantly symmetric fission due to the washing out of nuclear shell effects. From a comparison with the dynamical calculation based on the fluctuation-dissipation model, this behavior of the mass distributions was unambiguously attributed to the effect of multichance fission.

  13. Noble gases in the howardites Bholghati and Kapoeta

    Science.gov (United States)

    Swindle, T. D.; Hohenberg, C. M.; Nickols, R. H.; Olinger, C.; Garrison, D. H.; Goswami, J. N.

    1990-01-01

    Analyses of noble gases in whole rock samples of the howardites Bholghati and Kapoeta and grain-size separates of Kapoeta yield evidence for excesses of the Xe isotopes Xe-129 , Xe-131, Xe-132, Xe-134, and Xe-136 in a low-temperture component, similar to lunar excess fission Xe. Such a component may be able to provide chronometric information if the relative abundances of radioactive progenitors (I-129, Pu-244, and U-238) can be determined, but the isotopic spectra obtained are not sufficiently precise to do so. Eucritic clast BH-5 in Bholghati contains Xe produced in situ by the decay of Pu-244. Calculated fission Xe retention ages are 30-70 Ma after the formation of the solar system, consistent with the apparent presence of Sm-146 decay products. Both the clast and the matrix of Bholghati have K-Ar ages of about 2 Ga, suggesting a common thermal event at least that recently.

  14. Sequential Injection Method for Rapid and Simultaneous Determination of 236U, 237Np, and Pu Isotopes in Seawater

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Steier, Peter

    2013-01-01

    target analytes, whereupon plutonium and neptunium were simultaneously isolated and purified on TEVA, while uranium was collected on UTEVA. The separation behavior of U, Np, and Pu on TEVA–UTEVA columns was investigated in detail in order to achieve high chemical yields and complete purification...... for the radionuclides of interest. 242Pu was used as a chemical yield tracer for both plutonium and neptunium. 238U was quantified in the sample before the separation for deducing the 236U concentration from the measured 236U/238U atomic ratio in the separated uranium target using accelerator mass spectrometry....... Plutonium isotopes and 237Np were measured using inductively coupled plasma mass spectrometry after separation. The analytical results indicate that the developed method is robust and efficient, providing satisfactory chemical yields (70–100%) of target analytes and relatively short analytical time (8 h/sample)....

  15. Des analogues naturels de sites de stockage de déchets nucléaires vieux de 2 milliards d'années : les réacteurs de fission nucléaire naturels du Gabon (Afrique)

    Science.gov (United States)

    Gauthier-Lafaye, François

    2002-10-01

    Two billion years ago, the increase of oxygen in atmosphere and the high 235U/ 238U uranium ratio (>3%) made possible the occurrence of natural nuclear reactors on Earth. These reactors are considered to be a good natural analogue for nuclear waste disposal. Their preservation during such a long period of time is mainly due to the geological stability of the site, the occurrence of clays surrounding the reactors and acting as an impermeable shield, and the occurrence of organic matter that maintained the environment in reducing conditions, favourable for the stability of uraninite. Hydrogeochemical studies and modelling have shown the complexity of the geochemical system at Oklo and Bangombé (Gabon) and the lack of precise data about uranium and fission products retention and migration mechanisms in geological environments. To cite this article: F. Gauthier-Lafaye, C. R. Physique 3 (2002) 839-849.

  16. 230Th/U ages Supporting Hanford Site-Wide Probabilistic Seismic Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Paces, James B. [U.S. Geological Survey

    2014-08-31

    This product represents a USGS Administrative Report that discusses samples and methods used to conduct uranium-series isotope analyses and resulting ages and initial 234U/238U activity ratios of pedogenic cements developed in several different surfaces in the Hanford area middle to late Pleistocene. Samples were collected and dated to provide calibration of soil development in surface deposits that are being used in the Hanford Site-Wide probabilistic seismic hazard analysis conducted by AMEC. The report includes description of sample locations and physical characteristics, sample preparation, chemical processing and mass spectrometry, analytical results, and calculated ages for individual sites. Ages of innermost rinds on a number of samples from five sites in eastern Washington are consistent with a range of minimum depositional ages from 17 ka for cataclysmic flood deposits to greater than 500 ka for alluvium at several sites.

  17. Dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources

    Science.gov (United States)

    Barty, Christopher P.J.

    2013-02-05

    A dual isotope notch observer for isotope identification, assay and imaging with mono-energetic gamma-ray sources includes a detector arrangement consists of three detectors downstream from the object under observation. The latter detector, which operates as a beam monitor, is an integrating detector that monitors the total beam power arriving at its surface. The first detector and the middle detector each include an integrating detector surrounding a foil. The foils of these two detectors are made of the same atomic material, but each foil is a different isotope, e.g., the first foil may comprise U235 and second foil may comprise U238. The integrating detectors surrounding these pieces of foil measure the total power scattered from the foil and can be similar in composition to the final beam monitor. Non-resonant photons will, after calibration, scatter equally from both foils.

  18. Group Constants Generation of the Pseudo Fission Products for Fast Reactor Burnup Calculations

    Science.gov (United States)

    Gil, Choong-Sup; Kim, Do Heon; Chang, Jonghwa

    2005-05-01

    The pseudo fission products for the burnup calculations of the liquid metal fast reactor were generated. The cross-section data and fission product yield data of ENDF/B-VI were used for the pseudo fission product data of U-235, U-238, Pu-239, Pu-240, Pu-241, and Pu-242. The pseudo fission product data can be used with the KAFAX-F22 or -E66, which are the MATXS-format libraries for analyses of the liquid metal fast reactor at KAERI and were distributed through the OECD/NEA. The 80-group MATXS-format libraries of the 172 fission products were generated and the burnup chains for generation of the pseudo fission products were prepared.

  19. The Gas Handling System Assembly for the NIFFTE TPC

    Science.gov (United States)

    Duke, Dana

    2010-11-01

    The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) uses a Time Projection Chamber (TPC) to obtain more accurate measurements of the fission cross sections of radioactive isotopes such as Pu-239, U-235, U-238, etc. Past cross-section measurements have used various detection methods such as the parallel plate ionization chamber, but by using a TPC, accuracy levels can be improved to sub 1% error. Analysis of TPC data will improve the current understanding of fission dynamics and the fission process. The NIFFTE TPC is located at the 90L beam line at LANSCE-WNR where targets are bombarded with fast neutrons to induce fission. The resulting fission fragments are tracked using gas ionization within the TPC. Gas handling system function and assembly is examined and justified. Major components of the system include solenoid valves, pressure transducers, and mass flow controllers. This gas handling system has the capability of remotely controlling the flow of multiple gas sources into the TPC.

  20. β decay of Cd129 and excited states in In129

    Energy Technology Data Exchange (ETDEWEB)

    Taprogge, J.; Jungclaus, A.; Grawe, H.; Nishimura, S.; Doornenbal, P.; Lorusso, G.; Simpson, G. S.; Söderström, P. -A.; Sumikama, T.; Xu, Z. Y.; Baba, H.; Browne, F.; Fukuda, N.; Gernhäuser, R.; Gey, G.; Inabe, N.; Isobe, T.; Jung, H. S.; Kameda, D.; Kim, G. D.; Kim, Y. -K.; Kojouharov, I.; Kubo, T.; Kurz, N.; Kwon, Y. K.; Li, Z.; Sakurai, H.; Schaffner, H.; Steiger, K.; Suzuki, H.; Takeda, H.; Vajta, Zs.; Watanabe, H.; Wu, J.; Yagi, A.; Yoshinaga, K.; Benzoni, G.; Bönig, S.; Chae, K. Y.; Coraggio, L.; Covello, A.; Daugas, J. -M.; Drouet, F.; Gadea, A.; Gargano, A.; Ilieva, S.; Kondev, F. G.; Kröll, T.; Lane, G. J.; Montaner-Pizá, A.; Moschner, K.; Mücher, D.; Naqvi, F.; Niikura, M.; Nishibata, H.; Odahara, A.; Orlandi, R.; Patel, Z.; Podolyák, Zs.; Wendt, A.

    2015-05-01

    The beta decay of Cd-129, produced in the relativistic fission of a U-238 beam, was experimentally studied at the RIBF facility at the RIKEN Nishina Center. From the gamma radiation emitted after the beta decays, a level scheme of In-129 was established comprising 31 excited states and 69 gamma-ray transitions. The experimentally determined level energies are compared to state-of-the-art shell-model calculations. The half-lives of the two beta-decaying states in Cd-129 were deduced and the beta feeding to excited states in In-129 were analyzed. It is found that, as in most cases in the Z < 50, N <= 82 region, both decays are dominated by the nu 0g(7/2) -> pi 0g(9/2) Gamow-Teller transition, although the contribution of first-forbidden transitions cannot be neglected.

  1. Comparative Analysis on Nuclear Fuel Sustainability Aspect of FBR

    Science.gov (United States)

    Permana, Sidik; Irwanto, Dwi; Suzuki, Mitsutoshi; Saito, Masaki

    2017-01-01

    Recycle program of spent nuclear fuel (SNF) will have some challanges in term of fuel cycle capability and its facilities as well as nuclear non-proliferation concern of special nuclear materials. A different analysis approach as a comparative study have been analyzed based on breeding ratio and heavy metal inventory ratio concepts in fast breeder reactor (FBR) type. Breeding ratio and heavy metal inventory obtain higher than unity which shows breeding gain or surplus inventory of heavy metals are obtained. Breeding ratio indicates the fuel conversion capability from conversion process of fertile materials into fissile material such as fertile materials of U-238, Pu-238, Pu-240 and fissile materials of Pu-239 and Pu-241. Inventory ratio approaches are appropriate to estimate some selected actinide as a mass inventory production such as plutonium inventory ratio which estimate the surplus mass inventory from the ratio of produced plutonium at the net of operation to the initial inventory ratio.

  2. Measurements of gamma-ray production cross sections for shielding materials of space nuclear systems

    Science.gov (United States)

    Orphan, V. J.; John, J.; Hoot, C. G.

    1972-01-01

    Measurements of secondary gamma ray production from neutron interactions have been made over the entire energy range of interest in shielding applications. The epithermal capture gamma ray yields for both resolved gamma ray lines and continuum have been measured from thermal energies to 100 KeV for natural tungsten and U-238, two important candidate shield materials in SNAP reactor systems. Data are presented to illustrate the variation of epithermal capture gamma ray yields with neutron energy. The gamma ray production cross sections from (n,xy) reactions have been measured for Fe and Al from the threshold energies for inelastic scattering to approximately 16 MeV. Typical Fe and Al cross sections obtained with high-neutron energy resolution and averaged over broad neutron-energy groups are presented.

  3. Neutron-induced cross sections of actinides via the surrogate-reaction method

    Directory of Open Access Journals (Sweden)

    Ducasse Q.

    2013-12-01

    Full Text Available The surrogate-reaction method is an indirect way of determining cross sections for reactions that proceed through a compound nucleus. This technique may enable neutron-induced cross sections to be extracted for short-lived nuclei that otherwise cannot be measured. However, the validity of the surrogate method has to be investigated. In particular, the absence of a compound nucleus formation and the Jπ dependence of the decay probabilities may question the method. In this work we study the reactions 238U(d,p239U, 238U(3He,t238Np, 238U(3He,4He237U as surrogates for neutron-induced reactions on 238U, 237Np and 236U, respectively, for which good quality data exist. The experimental set-up enabled the measurement of fission and gamma-decay probabilities. The first results are hereby presented.

  4. Comparative analysis between measured and calculated concentrations of major actinides using destructive assay data from Ohi-2 PWR

    Directory of Open Access Journals (Sweden)

    Oettingen Mikołaj

    2015-09-01

    Full Text Available In the paper, we assess the accuracy of the Monte Carlo continuous energy burnup code (MCB in predicting final concentrations of major actinides in the spent nuclear fuel from commercial PWR. The Ohi-2 PWR irradiation experiment was chosen for the numerical reconstruction due to the availability of the final concentrations for eleven major actinides including five uranium isotopes (U-232, U-234, U-235, U-236, U-238 and six plutonium isotopes (Pu-236, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242. The main results were presented as a calculated-to-experimental ratio (C/E for measured and calculated final actinide concentrations. The good agreement in the range of ±5% was obtained for 78% C/E factors (43 out of 55. The MCB modeling shows significant improvement compared with the results of previous studies conducted on the Ohi-2 experiment, which proves the reliability and accuracy of the developed methodology.

  5. Activation of accelerator construction materials by heavy ions

    Science.gov (United States)

    Katrík, P.; Mustafin, E.; Hoffmann, D. H. H.; Pavlovič, M.; Strašík, I.

    2015-12-01

    Activation data for an aluminum target irradiated by 200 MeV/u 238U ion beam are presented in the paper. The target was irradiated in the stacked-foil geometry and analyzed using gamma-ray spectroscopy. The purpose of the experiment was to study the role of primary particles, projectile fragments, and target fragments in the activation process using the depth profiling of residual activity. The study brought information on which particles contribute dominantly to the target activation. The experimental data were compared with the Monte Carlo simulations by the FLUKA 2011.2c.0 code. This study is a part of a research program devoted to activation of accelerator construction materials by high-energy (⩾200 MeV/u) heavy ions at GSI Darmstadt. The experimental data are needed to validate the computer codes used for simulation of interaction of swift heavy ions with matter.

  6. Origin of uranium isotope variations in early solar nebula condensates.

    Science.gov (United States)

    Tissot, François L H; Dauphas, Nicolas; Grossman, Lawrence

    2016-03-01

    High-temperature condensates found in meteorites display uranium isotopic variations ((235)U/(238)U), which complicate dating the solar system's formation and whose origin remains mysterious. It is possible that these variations are due to the decay of the short-lived radionuclide (247)Cm (t 1/2 = 15.6 My) into (235)U, but they could also be due to uranium kinetic isotopic fractionation during condensation. We report uranium isotope measurements of meteoritic refractory inclusions that reveal excesses of (235)U reaching ~+6% relative to average solar system composition, which can only be due to the decay of (247)Cm. This allows us to constrain the (247)Cm/(235)U ratio at solar system formation to (1.1 ± 0.3) × 10(-4). This value provides new clues on the universality of the nucleosynthetic r-process of rapid neutron capture.

  7. Analysis of the FIC detector data at the n_TOF facility

    CERN Document Server

    Karadimos, D; Papachristodoulou, C; Vlachoudis, V; Assimakopoulos, P; Ioannides, K; Vlastou, R; Karamanis, D; Tsagas, N; Cennini, P; Konovalov, V; Ketlerov, V

    2010-01-01

    Fission cross-section measurements with the Fast Ionization Chamber (FIC) at the CERN n\\_TOF facility were challenged by intense signals due to gamma-rays and ultra-relativistic particles from the impact of the 20 GeV proton pulses on the neutron spallation target. A method for analyzing the data taken with Flash Analog to Digital Converters (FADC) was developed to treat these problems in an automated way to provide a reliable background subtraction and a fit routine for identifying fission events even at high energies. The analysis is illustrated at the example of the fission cross-section of U-238 relative to that of U-235 in the energy range from 40 key to 300 MeV. (C) 2010 Elsevier B.V. All rights reserved.

  8. New Fe-56 Evaluation for the CIELO project

    Energy Technology Data Exchange (ETDEWEB)

    Nobre, G P [Brookhaven National Laboratory (BNL); Herman, Micheal W [Brookhaven National Laboratory (BNL); Brown, D A [Brookhaven National Laboratory (BNL); Capote, R. [International Atomic Energy Agency (IAEA), Vienna / Austria and Universidad de Sevilla, Spain; Trkov, A. [International Atomic Energy Agency (IAEA); Leal, Luiz C [ORNL; Plompen, A. [Institute for Reference Materials and Measurements (IRMM), Geel, Belgium; Danon, Y. [Rensselaer Polytechnic Institute (RPI); Qian, Jing [China Nuclear Data Center; Ge, Zhigang [China Nuclear Data Center; Liu, Tingjin [China Nuclear Data Center; Lu, Hnalin [China Institute of Atomic Energy (CIAE); Ruan, Xichao [China Institute of Atomic Energy (CIAE)

    2016-01-01

    The Collaborative International Evaluated Library Organisation (CIELO) aims to provide revised and updated evaluations for Pu-239, U-238,U-235, Fe-56, O-16, and H-1 through international collaboration. This work, which is part of the CIELO project, presents the initial results for the evaluation of the Fe-56 isotope, with neutron-incident energy ranging from 0 to 20 MeV. The Fe-56(n,p) cross sections were fitted to reproduce the ones from IRDFF dosimetry file. Our preliminary file provides good cross-section agreements for the main angle-integrated reactions, as well as a reasonable overall agreement for angular distributions and double-differential spectra, when compared to previous evaluations.

  9. Current estimates of the energy released following the fission of actinide nuclides

    Science.gov (United States)

    Sonzogni, Alejandro; McCutchan, Elizabeth

    2017-09-01

    We calculate the energy released following the neutron induced fission of the main fuel nuclides in a reactor, 235U, 238U, 239Pu and 241Pu. These energies are used in a number of fields, but we were particularly motivated by their application in the recent measurements of reactor antineutrinos spectra and yields. The calculations are performed using the best estimates of cumulative fission yields for long-lived fission products and the recently released 2016 Atomic Mass Evaluation by Wang et al. Additionally, we obtain more precise values of the energy taken away by antineutrinos by using the latest Total Absorption Gamma Spectroscopy (TAGS) results. An important part of this project is also to obtain realistic estimates of the uncertainties. A comparison with earlier calculations will be presented. Work at Brookhaven National Laboratory was sponsored by the Office of Nuclear Physics, Office of Science of the U.S. Department of Energy under Contract No. DE-AC0298CH10886.

  10. Implications from Luna 24 sample 24170 to U-Pb evolution in the lunar mantle

    Science.gov (United States)

    Unruh, D. M.; Tatsumoto, M.

    1978-01-01

    The concentrations of U, Th and Pb, as well as the Pb isotopic composition, have been determined for a Luna 24 sample from the Mare Crisium area. A relatively recent disturbance to the U-Pb system during meteorite impact or burial in hot ejecta is suggested by the findings. According to three-stage U-Pb evolution model calculations, the source cumulates of the Luna 24 basalt evolved in a U-238/Pb-204 environment much lower than that of the Apollo mare basalts. A laterally heterogeneous lunar magma ocean, U-Pb fractionation during cumulate formation, and/or lack of KREEP addition to the Luna 24 basalt are also reflected in the calculations.

  11. Description and user manual of the WIMSLIC, FIXER and COMPA programs; Descripcion y manual del usuario de los programas WIMSLIC, FIXER y COMPA

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar H, F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    1992-08-15

    In this work the WIMS library and those WIMSLIC, FIXER and COMPA codes that are used to give him maintenance or to create a new one, the way to use them and its scopes are described. The objective of WIMSLIC, is the one of generating data nuclear with the WIMS code format, uses those results obtained with the NJOY system and the one POWR module, the FIXER function is to generate a new WIMS library or to already modify an existent, using the results of the one WIMSLIC code or those obtained with NJOY and WIMSR, while the COMPA function is to compare data groups with WIMS format. In the Appendix 1 the files of data are had that would use to generate a new library of WIMS that contain nuclear data for U-235, U-238, H-1, 0-16 and Al-27. In the Appendix 2 one has the listing of the programs before mentioned. (Author)

  12. Study of Photon Strength Functions of Actinides: the case of U-235, Np-238 and Pu-241

    CERN Document Server

    Guerrero, C; Cano-Ott, D; Martinez, T; Mendoza, E; Villamarin, D; Colonna, N; Meaze, M H; Marrone, S; Tagliente, G; Terlizzi, R; Belloni, F; Abbondanno, U; Fujii, K; Milazzo, P M; Moreau, C; Aerts, G; Berthoumieux, E; Dridi, W; Gunsing, F; Pancin, J; Perrot, L; Plukis, A; Alvarez, H; Duran, I; Paradela, C; Andriamonje, S; Calviani, M; Chiaveri, E; Gonzalez-Romero, E; Kadi, Y; Vicente, M C; Vlachoudis, V; Andrzejewski, J; Marganiec, J; Assimakopoulos, P; Karadimos, D; Karamanis, D; Papachristodoulou, C; Patronis, N; Audouin, L; David, S; Ferrant, L; Isaev, S; Stephan, C; Tassan-Got, L; Badurek, G; Jericha, E; Leeb, H; Oberhummer, H; Pigni, M T; Baumann, P; Kerveno, M; Lukic, S; Rudolf, G; Becvar, F; Krticka, M; Calvino, F; Capote, R; Carrillo De Albornoz, A; Marques, L; Salgado, J; Tavora, L; Vaz, P; Cennini, P; Dahlfors, M; Ferrari, A; Gramegna, F; Herrera-Martinez, A; Mastinu, P; Praena, J; Sarchiapone, L; Wendler, H; Chepel, V; Ferreira-Marques, R; Goncalves, I; Lindote, A; Lopes, I; Neves, F; Cortes, G; Poch, A; Pretel, C; Couture, A; Cox, J; O'brien, S; Wiescher, M; Dillman, I; Kappeler, F; Mosconi, M; Plag, R; Voss, F; Walter, S; Wisshak, K; Dolfini, R; Rubbia, C; Domingo-Pardo, C; Tain, J L; Eleftheriadis, C; Savvidis, I; Frais-Koelbl, H; Griesmayer, E; Furman, W; Konovalov, V; Goverdovski, A; Ketlerov, V; Haas, B; Haight, R; Reifarth, R; Heil, M; Igashira, M; Koehler, P; Kossionides, E; Lampoudis, C; Lozano, M; Quesada, J; Massimi, C; Vannini, G; Mengoni, A; Oshima, M; Papadopoulos, C; Vlastou, R; Pavlik, A; Pavlopoulos, P; Plompen, A; Rullhusen, P; Rauscher, T; Rosetti, M; Ventura, A

    2011-01-01

    The decay from excited levels in medium and heavy nuclei can be described in a statistical approach by means of Photon Strength Functions and Level Density distributions combined with the theory of the compound. The study of electromagnetic cascades following neutron capture by means of high efficiency detectors has been shown to be well suited for probing the properties of the Photon Strength Function of heavy (high level density) and/or radioactive (high background) nuclei. In this work we have investigated for the first time the validity of the recommended PSF for actinides, in particular 235U, 238Np and 241Pu. Our study includes the search for resonance structures in the PSF below Sn and draws conclusions regarding their existence and their characteristics in terms of energy, width and electromagnetic nature.

  13. Estimated dose to man from uranium milling via the terrestrial food-chain pathway

    Energy Technology Data Exchange (ETDEWEB)

    Rayno, D.R.

    1982-01-01

    One of the major pathways of radiological exposure to man from uranium milling operations is through the terrestrial food chain. Studies by various investigators have shown the extent of uptake and distribution of U-238, U-234, Th-230, Ra-226, Pb-210, and Po-210 in plants and animals. These long-lived natural radioisotopes, all nuclides of the uranium decay series, are found in concentrated amounts in uranium mill tailings. Data from these investigations are used to estimate the dose to man from consumption of beef and milk contaminated by the tailings. This dose estimate from this technologically enhanced source is compared with that from average normal dietary intake of these radionuclides from natural sources.

  14. Rapid Multisample Analysis for Simultaneous Determination of Anthropogenic Radionuclides in Marine Environment

    DEFF Research Database (Denmark)

    Qiao, Jixin; Shi, Keliang; Hou, Xiaolin

    2014-01-01

    of nearly quantitative dissolution of uranium in 6 mol/L sodium hydroxide solution. Automated extraction (TEVA for technetium and UTEVA for uranium) and anion exchange (AGMP-1 M for plutonium and neptunium) chromatographic separations were performed for further purification of each analyte within the FI...... Bq/m(3) (0.010 fg/L), 84 mu Bq/m(3) (0.010 fg/L) and 0.6 mBq/m(3) (0.048 ng/L) for Tc-99, Np-237, Pu-239, Pu-240 and U-238 for 200 L seawater, respectively. The unique feature of multiradionuclide and multisample simultaneous processing vitalizes the developed method as a powerful tool in obtaining...

  15. Analysis of solid uranium samples using a small mass spectrometer

    Science.gov (United States)

    Kahr, Michael S.; Abney, Kent D.; Olivares, José A.

    2001-07-01

    A mass spectrometer for isotopic analysis of solid uranium samples has been constructed and evaluated. This system employs the fluorinating agent chlorine trifluoride (ClF 3) to convert solid uranium samples into their volatile uranium hexafluorides (UF 6). The majority of unwanted gaseous byproducts and remaining ClF 3 are removed from the sample vessel by condensing the UF 6 and then pumping away the unwanted gases. The UF 6 gas is then introduced into a quadrupole mass spectrometer and ionized by electron impact ionization. The doubly charged bare metal uranium ion (U 2+) is used to determine the U 235/U 238 isotopic ratio. Precision and accuracy for several isotopic standards were found to be better than 12%, without further calibration of the system. The analysis can be completed in 25 min from sample loading, to UF 6 reaction, to mass spectral analysis. The method is amenable to uranium solid matrices, and other actinides.

  16. Investigating uranium distribution in surface sediments and waters: a case study of contamination from the Juniper Uranium Mine, Stanislaus National Forest, CA.

    Science.gov (United States)

    Kayzar, Theresa M; Villa, Adam C; Lobaugh, Megan L; Gaffney, Amy M; Williams, Ross W

    2014-10-01

    The uranium concentrations and isotopic compositions of waters, sediment leachates and sediments from Red Rock Creek in the Stanislaus National Forest of California were measured to investigate the transport of uranium from a point source (the Juniper Uranium Mine) to a natural surface stream environment. The ((234)U)/((238)U) composition of Red Rock Creek is altered downstream of the Juniper Mine. As a result of mine-derived contamination, water ((234)U)/((238)U) ratios are 67% lower than in water upstream of the mine (1.114-1.127 ± 0.009 in the contaminated waters versus 1.676 in the clean branch of the stream), and sediment samples have activity ratios in equilibrium in the clean creek and out of equilibrium in the contaminated creek (1.041-1.102 ± 0.007). Uranium concentrations in water, sediment and sediment leachates are highest downstream of the mine, but decrease rapidly after mixing with the clean branch of the stream. Uranium content and compositions of the contaminated creek headwaters relative to the mine tailings of the Juniper Mine suggest that uranium has been weathered from the mine and deposited in the creek. The distribution of uranium between sediment surfaces (leachable fraction) and bulk sediment suggests that adsorption is a key element of transfer along the creek. In clean creek samples, uranium is concentrated in the sediment residues, whereas in the contaminated creek, uranium is concentrated on the sediment surfaces (∼70-80% of uranium in leachable fraction). Contamination only exceeds the EPA maximum contaminant level (MCL) for drinking water in the sample with the closest proximity to the mine. Isotopic characterization of the uranium in this system coupled with concentration measurements suggest that the current state of contamination in Red Rock Creek is best described by mixing between the clean creek and contaminated upper branch of Red Rock Creek rather than mixing directly with mine sediment. Published by Elsevier Ltd.

  17. Uranium and plutonium in anoxic marine sediments of the Santiago River mouth (Eastern Pacific, Mexico).

    Science.gov (United States)

    Almazán-Torres, María Guadalupe; Ordóñez-Regil, Eduardo; Ruiz-Fernández, Ana Carolina

    2016-11-01

    The uranium (U) and plutonium (Pu) content with depth in a sediment core collected in the continental shelf off the mouth of the Santiago River in the Mexican Pacific was studied to evaluate the contamination effects of the effluent of the Santiago-Lerma River as it moves into the sea. The large mass of terrestrial detritus delivered by the river influences the physicochemical and geochemical processes in the seafloor. Abnormal concentrations of U and Pu in sediments were examined as indicative of the effects of anoxic conditions. One of the indicators of pollution of seawater is the bacterial activity of the shallow seabed layer; and among the prevailing bacteria, the magnetotactic ones induce the formation of euhedral and framboidal shapes (pyrite). These pyrite entities are by-products of anoxic environments loaded with decomposing detrital material and are very abundant in the surface layers of the sediment core analyzed. The pyrite formation is the result of a biochemical reaction between iron and organic sulphur reduced by bacteria, and the pyrite entities precipitate to the seafloor. In the same upper zone of the profile, 238 U is readily immobilized, while 234 U is oxidized and dissolved in seawater by the effect of hot atom chemistry. This may cause the activity ratio (AR) 234 U/ 238 U disequilibrium (near 0.41). Furthermore, in the shallow layer of the sediment core, an abnormally high concentration of 239+240 Pu was detected. In this upper layer, the activity concentrations found were 3.19 Bq kg -1 for 238 U, 1.32 kg -1 for 234 U and 2.78 Bq kg -1 for 239+240 Pu. In the lower fractions of the sediment core, normal values of AR 234 U/ 238 U (≈1) were found, with traces of 239+240 Pu. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Air and radon pathways screenings methodologies for the next revision of the E-area PA

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, J. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-10-31

    The strategic plan for the next E-Area Low-Level Waste Facility Performance Assessment includes recommended changes to the screening criteria used to reduce the number of radioisotopes that are to be considered in the air and radon pathways incorporated into the GoldSim® atmospheric release model (ARM). For the air pathway, a revised screening methodology was developed based on refinement of previous E-Area PA screening approaches and consideration of the strategic plan recommendations. The revised methodology has three sequential screening steps for each radioisotope: (1) volatility test using the Periodic Table of the Elements, (2) stability test based on half-life, and (3) stability test based on volatility as measured by the Henry’s Law constant for the assumed dominant gaseous species or vapor pressure in the case of tritiated water. Of the 1252 radioisotopes listed in the International Commission on Radiological Protection Publication 107, only the 10 that satisfied all three steps of the revised screening methodology will be included in the ARM. They are: Ar-37, Ar-39, Ar-42, C-14, H-3, Hg-194, Hg-203, Kr-81, Kr-85, and Xe-127. For the radon pathway, a revised screening methodology was developed that also has three sequential steps: (1) identify all decay chains that terminate at Rn-222, (2) screen out parents that decay through U-238 because of its 4.5-billion-year primordial half-life, and (3) eliminate remaining parents whose half-life is shorter than one day. Of the 86 possible decay chains leading to Rn-222, six decay chains consist of 15 unique radioisotopes that will be incorporated into the ARM. The 15 radioisotopes are: U-238, Th-234, Pa-234m, Pu-238, U-234, Th-230, Ra-226, Cf-246, Cm-242, Am-242m, Am-242, Np-238, Np-234, Pa-230, and Rn-222.

  19. The chronology for the d18O record from Devils Hole, Nevada, extended into the Mid-Holocene

    Science.gov (United States)

    Landwehr, J.M.; Sharp, W.D.; Coplen, T.B.; Ludwig, K. R.; Winograd, I.J.

    2011-01-01

    This report presents the numeric values for the chronology of the paleoclimatically relevant mid-to-late Pleistocene record of the ratios of stable oxygen isotope (delta18O) in vein calcite from Devils Hole, Nev., which recently had been extended into the mid-Holocene. Dating was obtained using 230Th-234U-238U thermal ionization mass spectrometry. Devils Hole is a subaqueous cave of tectonic origin, which developed in the discharge zone of a regional aquifer in south-central Nevada. The primary groundwater recharge source area is the Spring Mountains, the highest mountain range in southern Nevada [altitude 3,630 meters (m)], approximately 80 kilometers to the east of the cavern. The walls of the open fault zone comprising the cave system are coated with dense vein calcite precipitated from the through-flowing groundwater. The calcite, up to 40 centimeters (cm) thick, contains a continuous record of the sequential variation of the composition of stable oxygen isotopes in the ground water over time. The vein calcite has also proven to be a suitable material for precise uranium-series dating via thermal ionization mass spectrometry utilizing the 230Th-234U-238U decay clock. Earlier work has presented data from the Devils Hole core DH-11, a 36-cm-long core of vein calcite recovered from a depth of about 30 m below the water table (about 45 m beneath the ground surface). The DH-11 core provided a continuous record of isotopic oxygen variation from 567,700 to 59,800 years before present. Recent work has extended this record up to 4,500 years before present, into the mid-Holocene epoch.

  20. Uranium comminution age tested by the eolian deposits on the Chinese Loess Plateau

    Science.gov (United States)

    Li, Le; Liu, Xiangjun; Li, Tao; Li, Laifeng; Zhao, Liang; Ji, Junfeng; Chen, Jun; Li, Gaojun

    2017-06-01

    The 234U/238U ratio of fine particles can record the time since their separation from bed rock because of the disruption of uranium series equilibrium introduced by the recoil of daughter 234Th nuclei (precursor of 234U) out of particle surfaces during the decay of 238U. Application of the uranium comminution age method, which has great potential in tracing production and transportation of sediments is however complicated by the weathering dissolution of 234U depleted particle surfaces, the difficulty in determining the fraction of recoiled nuclei, and the precipitation of exogenetic 234U. Here we minimize these complications by using a newly developed precise size separation using electroformed sieve, and a chemical protocol that involves reductive and oxidative leaching. Eolian deposits collected from the Chinese Loess Plateau (CLP) were used to test the validity of our method. Possible effects of weathering dissolution were also evaluated by comparing samples with different weathering intensities. The results show decreasing 234U/238U ratios in fine eolian particles with increasing sedimentation age, agreeing well with the theoretical prediction of the comminution age model. This successful application of the uranium comminution age approach to the eolian deposits on the CLP is also aided by a stable dust source, the low weathering intensity, the lack of consolidation, and the well-defined age model of the deposits. A transportation time of 242 ± 18 ka was calculated for the eolian deposits, which indicates a long residence time, and thus extensive mixing, of the dust particles in source regions, partly explaining the stable and homogeneous composition of the eolian dust over glacial-interglacial cycles.

  1. Vertical distribution of236U in the North Pacific Ocean.

    Science.gov (United States)

    Eigl, R; Steier, P; Sakata, K; Sakaguchi, A

    2017-04-01

    The first extensive study on 236 U in the North Pacific Ocean has been conducted. The vertical distribution of 236 U/ 238 U isotopic ratios and the 236 U concentrations were analysed on seven depth profiles, and large variations with depth were found. The range of 236 U/ 238 U isotopic ratios was from (0.09 ± 0.03) × 10 -10 to (14.1 ± 2.2) × 10 -10 , which corresponds to 236 U concentrations of (0.69 ± 0.24) × 10 5 atoms/kg and (119 ± 21) × 10 5 atoms/kg, respectively. The variations in 236 U concentrations could mainly be attributed to the different water masses in the North Pacific Ocean and their formation processes. Uranium-236 inventories on the water column of each sampling station were calculated and varied between (3.89 ± 0.08) × 10 12 atoms/m 2 and (7.03 ± 0.50) × 10 12 atoms/m 2 , which is lower than in former studies on comparable latitudes in the North Atlantic Ocean and the Sea of Japan. The low inventories of 236 U found for the North Pacific Ocean in this study can be explained by the lack of additional input sources of artificial radionuclides, apart from global and regional/local fallout. This study expands the use of 236 U as oceanographic circulation tracer to yet another ocean basin and shows that this isotope can be used for tracing circulation patterns of water masses in the Pacific Ocean. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Uranium isotopes in well water samples as drinking sources in some settlements around the Semipalatinsk Nuclear Test Site, Kazakhstan.

    Science.gov (United States)

    Yamamoto, Masayoshi; Tomita, Junpei; Sakaguchi, Aya; Ohtsuka, Yoshihito; Hoshi, Masaharu; Apsalikov, Kazbek N

    Radiochemical results of U isotopes (234U, 235U and 238U) and their activity ratios are reported for well waters as local sources of drinking waters collected from the ten settlements around the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan. The results show that 238U varies widely from 3.6 to 356 mBq/L (0.3-28.7 μg/L), with a factor of about 100. The 238U concentrations in some water samples from Dolon, Tailan, Sarzhal and Karaul settlements are comparable to or higher than the World Health Organization's restrictive proposed guideline of 15 μg (U)/L. The 234U/238U activity ratios in the measured water samples are higher than 1, and vary between 1.1 and 7.9, being mostly from 1.5 to 3. The measured 235U/238U activity ratios are around 0.046, indicating that U in these well waters is of natural origin. It is probable that the elevated concentration of 238U found in some settlements around the SNTS is not due to the close-in fallout from nuclear explosions at the SNTS, but rather to the intensive weathering of rocks including U there. The calculated effective doses to adults resulting from consumption of the investigated waters are in the range 1.0-18.7 μSv/y. Those doses are lower than WHO and IAEA reference value (100 μSv/y) for drinking water.

  3. Determination of uranium isotope ratios using a liquid sampling atmospheric pressure glow discharge/Orbitrap mass spectrometer system.

    Science.gov (United States)

    Hoegg, Edward D; Marcus, R Kenneth; Koppenaal, David W; Irvahn, Jan; Hager, George J; Hart, Garret L

    2017-09-30

    The field of highly accurate and precise isotope ratio analysis, for use in nonproliferation, has been dominated by thermal ionization and inductively coupled plasma mass spectrometry. While these techniques are considered the gold standard for isotope ratio analysis, a downsized instrument capable of accurately and precisely measuring uranium (U) isotope ratios is desirable for field studies or in laboratories with limited infrastructure. The developed system interfaces the liquid sampling, an atmospheric pressure glow discharge (LS-APGD) ion source, with a high-resolution Exactive Orbitrap mass spectrometer. With this experimental setup certified U isotope standards and unknown samples were analyzed. The accuracy and precision of the system were then determined. The LS-APGD/Exactive instrument measured a certified reference material of natural U (235 U/238 U = 0.007261) with a 235 U/238 U ratio of 0.007065 and a % relative standard uncertainty of 0.082, meeting the International Target Values for the destructive analysis of U. In addition, when three unknowns were measured and these measurements were compared with the results from an ICP multi-collector instrument, there were no statistical differences between the two instruments. The LS-APGD/Orbitrap system, while still in the preliminary stages of development, offers highly accurate and precise isotope ratio results that suggest a potential paradigm shift in the world of isotope ratio analysis. Furthermore, the portability of the LS-APGD as an elemental ion source, combined with the small size and smaller operating demands of the Orbitrap, suggests that the instrumentation is capable of being field-deployable. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Investigating Pu and U isotopic compositions in sediments: a case study in Lake Obuchi, Rokkasho Village, Japan using sector-field ICP-MS and ICP-QMS.

    Science.gov (United States)

    Zheng, Jian; Yamada, Masatoshi

    2005-08-01

    The objectives of the present work were to study isotope ratios and the inventory of plutonium and uranium isotope compositions in sediments from Lake Obuchi, which is in the vicinity of several nuclear fuel facilities in Rokkasho, Japan. Pu and its isotopes were determined using sector-field ICP-MS and U and its isotopes were determined with ICP-QMS after separation and purification with a combination of ion-exchange and extraction chromatography. The observed (240)Pu/(239)Pu atom ratio (0.186 +/- 0.016) was similar to that of global fallout, indicating that the possible early tropospheric fallout Pu did not deliver Pu from the Pacific Proving Ground to areas above 40 degrees N. The previously reported higher Pu inventory in the deep water area of Lake Obuchi could be attributed to the lateral transportation of Pu deposited in the shallow area which resulted from the migration of deposited global fallout Pu from the land into the lake by river runoff and from the Pacific Ocean by tide movement and sea water scavenging, as well as from direct soil input by winds. The (235)U/(238)U atom ratios ranged from 0.00723 to 0.00732, indicating the natural origin of U in the sediments. The average (234)U/(238)U activity ratio of 1.11 in a sediment core indicated a significant sea water U contribution. No evidence was found for the release of U containing wastes from the nearby nuclear facilities. These results will serve as a reference baseline on the levels of Pu and U in the studied site so that any further contamination from the spent nuclear fuel reprocessing plants, the radioactive waste disposal and storage facilities, and the uranium enrichment plant can be identified, and the impact of future release can be rapidly assessed.

  5. Radiological exposure assessment from soil, underground and surface water in communities along the coast of a shallow water offshore oilfield in Ghana.

    Science.gov (United States)

    Kpeglo, D O; Mantero, J; Darko, E O; Emi-Reynolds, G; Akaho, E H K; Faanu, A; Garcia-Tenorio, R

    2015-02-01

    Radiometric determinations have been carried out to assess public exposure to radioactivity for communities along the coast of a shallow water offshore oilfield in Ghana (which started their operations recently) in order to establish baseline data using alpha spectrometry after radiochemical separation and non-destructive gamma spectrometry. The average activity concentrations of (234)U, (238)U, (230)Th and (232)Th by alpha-particle spectrometry and of (226)Ra, (228)Ra, (228)Th, (40)K, (210)Pb, (234)Th and (137)Cs by gamma-ray spectrometry were determined in the soil samples. The activity concentrations of (234)U, (238)U, (230)Th and (232)Th were determined in the water samples by alpha-particle spectrometry and of (226)Ra by liquid scintillation counting. The total annual effective dose to the public was estimated from the measured activity concentrations and this was clearly below the International Commission on Radiological Protection (ICRP) reference level of 1 mSv y(-1) for public exposure control. In addition, the estimated values of Raeq, Hex and Hin were all lower than the recommended acceptable values and the mean values of gross alpha and gross beta determinations performed for all the water samples give values that were all below the Ghana Standards Authority and World Health Organization recommended guideline values for drinking water quality. The results obtained show insignificant public exposure to radioactivity. However, this study provides important information for future studies on subsequent evaluations of the possible future environmental contamination due to activities of the oil industry in Ghana. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Natural uranium and strontium isotope tracers of water sources and surface water-groundwater interactions in arid wetlands: Pahranagat Valley, Nevada, USA

    Science.gov (United States)

    Paces, James B.; Wurster, Frederic C.

    2014-01-01

    Near-surface physical and chemical process can strongly affect dissolved-ion concentrations and stable isotope compositions of water in wetland settings, especially under arid climate conditions. In contrast, heavy radiogenic isotopes of strontium (87Sr/86Sr) and uranium (234U/238U) remain largely unaffected and can be used to help identify unique signatures from different sources and quantify end-member mixing that would otherwise be difficult to determine. The utility of combined Sr and U isotopes are demonstrated in this study of wetland habitats on the Pahranagat National Wildlife Refuge, which depend on supply from large-volume springs north of the Refuge, and from small-volume springs and seeps within the Refuge. Water budgets from these sources have not been quantified previously. Evaporation, transpiration, seasonally variable surface flow, and water management practices complicate the use of conventional methods for determining source contributions and mixing relations. In contrast, 87Sr/86Sr and 234U/238U remain unfractionated under these conditions, and compositions at a given site remain constant. Differences in Sr- and U-isotopic signatures between individual sites can be related by simple two- or three-component mixing models. Results indicate that surface flow constituting the Refuge’s irrigation source consists of a 65:25:10 mixture of water from two distinct regionally sourced carbonate aquifer springs, and groundwater from locally sourced volcanic aquifers. Within the Refuge, contributions from the irrigation source and local groundwater are readily determined and depend on proximity to those sources as well as water management practices.

  7. Tracing Anthropogenic Salinity Inputs to the Semi-arid Rio Grande River: A Multi-isotope Tracer (U, S, B and Sr) Approach

    Science.gov (United States)

    Garcia, S.; Nyachoti, S. K.; Ma, L.; Szynkiewicz, A.; McIntosh, J. C.

    2015-12-01

    High salinity in the Rio Grande has led to severe reductions in crop productivity and accumulation of salts in soils. These pressing issues exist for other arid rivers worldwide. Salinity contributions to the Rio Grande have not been adequately quantified, especially from agriculture, urban activities, and geological sources. Here, we use major element concentrations and U, S, B, Sr isotopic signatures to fingerprint the salinity sources. Our study area focuses on a 200 km long stretch of the Rio Grande from Elephant Butte Reservoir, NM to El Paso, TX. River samples were collected monthly from 2014 to 2015. Irrigation drains, groundwater wells, city drains and wastewater effluents were sampled as possible anthropogenic salinity end-members. Major element chemistry, U, S and Sr isotope ratios in the Rio Grande waters suggest multiple salinity inputs from geological, agricultural, and urban sources. Natural upwelling of groundwater is significant for the Rio Grande near Elephant Butte, as suggested by high TDS values and high (234U/238U), 87Sr/86Sr, δ34S ratios. Agricultural activities (e.g. flood irrigation, groundwater pumping, fertilizer use) are extensive in the Mesilla Valley. Rio Grande waters from this region have characteristic lower (234U/238U), 87Sr/86Sr, and δ34S ratios, with possible agricultural sources from use of fertilizers and gypsum. Agricultural practices during flood irrigation also intensify evaporation of Rio Grande surface water and considerably increase water salinity. Shallow groundwater signatures were also identified at several river locations, possibly due to the artificial pumping of local groundwater for irrigation. Impacts of urban activities to river chemistry (high NO3 and B concentrations) were evident for locations downstream to Las Cruces and El Paso wastewater treatment plants, supporting the use of the B isotope as an urban salinity tracer. This study improves our understanding of human impacts on water quality and elemental

  8. Do pyrotechnics contain radium?

    Energy Technology Data Exchange (ETDEWEB)

    Steinhauser, Georg; Musilek, Andreas, E-mail: georg.steinhauser@ati.ac.a [Vienna University of Technology, Atominstitut der Oesterreichischen Universitaeten, Stadionallee 2, A-1020 Wien (Austria)

    2009-07-15

    Many pyrotechnic devices contain barium nitrate which is used as an oxidizer and colouring agent primarily for green-coloured fireworks. Similarly, strontium nitrate is used for red-coloured pyrotechnic effects. Due to their chemical similarities to radium, barium and strontium ores can accumulate radium, causing a remarkable activity in these minerals. Radium in such contaminated raw materials can be processed together with the barium or strontium, unless extensive purification of the ores was undertaken. For example, the utilization of 'radiobarite' for the production of pyrotechnic ingredients can therefore cause atmospheric pollution with radium aerosols when the firework is displayed, resulting in negative health effects upon inhalation of these aerosols. In this study, we investigated the occurrence of gamma-photon-emitting radionuclides in several pyrotechnic devices. The highest specific activities were due to K-40 (up to 20 Bq g{sup -1}, average value 14 Bq g{sup -1}). Radium-226 activities were in the range of 16-260 mBq g{sup -1} (average value 81 mBq g{sup -1}). Since no uranium was found in any of the samples, indeed, a slight enrichment of Ra-226 in coloured pyrotechnics can be observed. Radioactive impurities stemming from the Th-232 decay chain were found in many samples as well. In the course of novel developments aiming at the 'greening' of pyrotechnics, the potential radioactive hazard should be considered as well.

  9. 1982 US-CEC neutron personnel dosimetry intercomparison study

    Energy Technology Data Exchange (ETDEWEB)

    Swaja, R.E.; Sims, C.S.; Greene, R.T.; Schraube, H.; Burger, G.

    1983-11-01

    A neutron personnel dosimetry intercomparison study was conducted during April 19-23, 1982, as a joint effort between the United States and the Commission of European Communities. Dosimeters from 48 participating agencies were mounted on cylindrical phantoms and exposed to a range of low-level dose equivalents (0.48-13.91 mSv neutron and 0.02-1.32 mSv gamma) in nine different radiation fields. Exposure conditions considered in this study included four mixed-field spectra produced using the Health Physics Research Reactor, four monoenergetic neutron fields generated by accelerators, and one 15-cm D/sub 2/O-moderated californium source spectrum. In general, neutron results reported by the participating agencies were consistent with expected dosimeter performance based on energy response characteristics of the detection systems. Albedo dosimeters, which were the most popular neutron monitoring systems used in this study, provided the best overall accuracy for all exposure conditions. Film, Cr-39 recoil track, and Th-232 fission track systems generally underestimated dose equivalents relative to reference values. Associated gamma measurements showed that TLD monitors produced more accurate results than film dosimeters although both systems overestimated gamma dose equivalents in mixed radiation fields. 24 references, 10 figures, 19 tables.

  10. [Marie Curie, née Maria Sklodowska (1867-1934)--contribution to the development of radiology].

    Science.gov (United States)

    Babić, Rade R; Babić, Gordana Stanković

    2011-01-01

    Marie Curie, née Maria Sklodowska, was born on November 7, 1867 in Warsaw (Poland). She suffered from leukaemia and died on June 4, 1934. She was buried with full honours at Pantheon. Marie Curie and her husband Pierre Curie discovered the radioactive elements Polonium (84Po210), Thorium (90Th232) and Radium (88Ra226). Marie Curie introduced the term radioactivity into science. She was the first woman who got Ph.D. in France, the first woman professor at Sorbonne, Paris and Medical Academy. Of all the women who have ever won the Nobel Prize, Marie Curie was the only who received it twice. During World War I Marie Curie designed a mobile x-ray room "radiologic car". Marie Curie had an x-ray machine installed into a car and demonstrated how to use its dynamo for electric power production necessary for the x-ray machine to work. She had 20 cars with moving radiological lab made and trained 150 people to work on them. She brought something radically new into military medicine--mobile x-ray diagnostics. With the discovery of radioactive elements a new medical branch, radiotherapy, was developed.

  11. The tragic history of thorotrast

    Energy Technology Data Exchange (ETDEWEB)

    Cuperschmid, Ethel Mizrahy [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Faculdade de Medicina. Centro de Memoria da Medicina], e-mail: ethelmizrahy@yahoo.com.br, e-mail: cememor@yahoor.com.br; Campos, Tarcisio Passos Ribeiro de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares], e-mail: campos@nuclear.ufmg.br

    2009-07-01

    Thorotrast, a colloidal solution of dioxide of natural thorium, slightly radioactive, had been applied on fluoroscopy applied since 1928 to the purpose of pielography, accomplishment for retrograde road, and to the contrast studies on the liver and on the spleen. The half-life of the thorium dioxide is 1,4 x 1010 years. Its biological half-life can be taken from the International Commission on Radiological Protection (ICRP) as 8,000 days in bone, with, bone uptake of 70%; 700 days in the liver with 4% of liver uptake; 700 days in all other tissues and organs, in which 16% of uptake . The remaining 10% has been assumed to be excreted with a halflife of 0.5 days. Its Th-232 disintegration produces a series of radionuclides following a emission of alpha and beta particles ending on Pb208, a stable nuclide. However, the whole thorium dioxide is almost retained in the organism, keeping 70% deposited in the liver, 20% in the spleen and the remaining in the bony medulla and in the peripheral linfonodes. Thorotrast became the choice of the majority of the neurosurgeries at that time, as Egas Moniz, that rejected the sodium iodine at 25% concentration to adopt Thorotrast. That contrast had been used unrestrictly until 1950. The present article presents the medical discuss about Throtrast and investigates its oncology effects on human. (author)

  12. Improved Limits on Axionlike-Particle-Mediated P , T -Violating Interactions between Electrons and Nucleons from Electric Dipole Moments of Atoms and Molecules

    Science.gov (United States)

    Stadnik, Y. V.; Dzuba, V. A.; Flambaum, V. V.

    2018-01-01

    In the presence of P , T -violating interactions, the exchange of axionlike particles between electrons and nucleons in atoms and molecules induces electric dipole moments (EDMs) of atoms and molecules. We perform calculations of such axion-exchange-induced atomic EDMs using the relativistic Hartree-Fock-Dirac method including electron core polarization corrections. We present analytical estimates to explain the dependence of these induced atomic EDMs on the axion mass and atomic parameters. From the experimental bounds on the EDMs of atoms and molecules, including Cs 133 , Tl 205 , Xe 129 , Hg 199 , Yb 171 F 19 , Hf 180 F+ 19 , and Th 232 O 16 , we constrain the P , T -violating scalar-pseudoscalar nucleon-electron and electron-electron interactions mediated by a generic axionlike particle of arbitrary mass. Our limits improve on existing laboratory bounds from other experiments by many orders of magnitude for ma≳10-2 eV . We also place constraints on C P violation in certain types of relaxion models.

  13. Radioactive wastes management in a radiochemistry laboratory; Gerencia de rejeitos radioativos em um laboratorio de radioquimica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ana C.A., E-mail: anasilva@inb.gov.b [Universidade Federal de Alfenas (UNIFAL), Pocos de Caldas, MG (Brazil). Curso de Bacharelado em Ciencia e Tecnologia; Pereira, Wagner de S; Py Junior, Delcy de A.; Antunes, Ivan M., E-mail: wspereira@inb.gov.b, E-mail: delcy@inb.gov.b, E-mail: ivan@inb.gov.b [Industrias Nucleares do Brazil (INB), Pocos de Caldas, MG (Brazil). Unidade de Tratamento de Minerios. Coordenacao de Protecao Radiologica; Kelecom, Alphonse, E-mail: kelecom@uol.com.b [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Biologia Marinha. Curso de Pos-Graduacao em Biologia Marinha

    2009-07-01

    The Laboratorio de Monitoracao Ambiental (AMB) of the Unidade de Tratamento de Minerio (UTM) belonging to the Industrias Nucleares do Brasil is a chemical, radiochemical and radiometric laboratory, that analyses the natural radionuclides present in samples coming from the various installation of Industrias Nucleares do Brasil (INB). To minimize the radiological environmental impact, that laboratory has adopted a washing system of the chapel exhausting, that recirculate the washing water. These water can accumulate the radionuclides coming from the samples, that are liberated together the exhaustion gases from the chapels. Also, the water coming from the analyses and the sample releases (environmental and of the process) represent the liquid effluents of the AMB. The release of this effluent must pass by chemical and radiological criteria. From the radiological viewpoint, that release must be based on the Brazilian Nuclear Energy Commission (CNEN) regulations. This work try to establish the monitoring frequency, the radionuclides to be analysed, the form of liberation of those effluents, and the analytical techniques to be used. The radionuclides to be analysed will be U-nat, Ra-226 and Pb-210, of the uranium series, and the Th-232 and Ra-228, of the thorium series. The effluents must be monitored either before the release or, at least, twice a year. The effluents considered radioactive wastes, will be send to waste dam by the radioprotection service, or to the effluent treatment for controlled liberation for the environment

  14. Fission fragments mass distributions of nuclei populated by the multinucleon transfer channels of the 18O+232Th reaction

    Directory of Open Access Journals (Sweden)

    R. Léguillon

    2016-10-01

    Full Text Available It is shown that the multinucleon transfer reactions is a powerful tool to study fission of exotic neutron-rich actinide nuclei, which cannot be accessed by particle-capture or heavy-ion fusion reactions. In this work, multinucleon transfer channels of the 18O+232Th reaction are used to study fission of fourteen nuclei 231,232,233,234Th, 232,233,234,235,236Pa, and 234,235,236,237,238U. Identification of fissioning nuclei and of their excitation energy is performed on an event-by-event basis, through the measurement of outgoing ejectile particle in coincidence with fission fragments. Fission fragment mass distributions are measured for each transfer channel, in selected bins of excitation energy. In particular, the mass distributions of 231,234Th and 234,235,236Pa are measured for the first time. Predominantly asymmetric fission is observed at low excitation energies for all studied cases, with a gradual increase of the symmetric mode towards higher excitation energy. The experimental distributions are found to be in general agreement with predictions of the fluctuation–dissipation model.

  15. Filling Knowledge Gaps with Five Fuel Cycle Studies

    Energy Technology Data Exchange (ETDEWEB)

    Steven J. Piet; Jess Gehin; William Halsey; Temitope Taiwo

    2010-11-01

    During FY 2010, five studies were conducted of technology families’ applicability to various fuel cycle strategies to fill in knowledge gaps in option space and to better understand trends and patterns. Here, a “technology family” is considered to be defined by a type of reactor and by selection of which actinides provide fuel. This report summarizes the higher-level findings; the detailed analyses and results are documented in five individual reports, as follows: • Advanced once through with uranium fuel in fast reactors (SFR), • Advanced once through (uranium fuel) or single recycle (TRU fuel) in high temperature gas cooled reactors (HTGR), • Sustained recycle with Th/U-233 in light water reactors (LWRs), • Sustained recycle with Th/U-233 in molten salt reactors (MSR), and • Several fuel cycle missions with Fusion-Fission Hybrid (FFH). Each study examined how the designated technology family could serve one or more designated fuel cycle missions, filling in gaps in overall option space. Each study contains one or more illustrative cases that show how the technology family could be used to meet a fuel cycle mission, as well as broader information on the technology family such as other potential fuel cycle missions for which insufficient information was available to include with an illustrative case. None of the illustrative cases can be considered as a reference, baseline, or nominal set of parameters for judging performance; the assessments were designed to assess areas of option space and were not meant to be optimized. There is no implication that any of the cases or technology families are necessarily the best way to meet a given fuel cycle mission. The studies provide five examples of 1-year fuel cycle assessments of technology families. There is reasonable coverage in the five studies of the performance areas of waste management and uranium utilization. The coverage of economics, safety, and proliferation resistance and physical protection in

  16. Graphic and algebraic solutions of the discordant lead-uranium age problem

    Science.gov (United States)

    Stieff, L.R.; Stern, T.W.

    1961-01-01

    Uranium-bearing minerals that give lead-uranium and lead-lead ages that are essentially in agreement, i.e. concordant, generally are considered to have had a relatively simple geologic history and to have been unaltered since their deposition. The concordant ages obtained on such materials are, therefore, assumed to approach closely the actual age of the minerals. Many uranium-bearing samples, particularly uranium ores, give the following discordant age sequences; Pb206 U238 older generation of radiogenic lead. The evaluation of discordant lead isotope age data may be separated into two operations. The first operation, with which this paper is concerned, is mechanical in nature and involves the calculation of the different possible concordant ages corresponding to the various processes assumed to have produced the discordant ages. The second operation is more difficult to define and requires, in part, some personal judgement. It includes a synthesis of the possible concordant age solutions with other independent geologic and isotopic evidence. The concordant age ultimately chosen as most acceptable should be consistent not only with the known events in the geologic history of the area, the age relations of the enclosing rocks, and the mineralogic and paragenetic evidence, but also with other independent age measurements and the isotopic data obtained on the lead in related or associated non-radioactive minerals. The calculation of the possible concordant ages from discordant age data has been greatly simplified by Wetherill's graphical method of plotting the mole ratios of radiogenic Pb206 U238 ( N206 N238) vs. radiogenic Pb207 U235 ( N207 N235) after correcting for the contaminating common Pb206 and Pb207. The linear relationships noted in this graphical procedure have been extended to plots of the mole ratios of total Pb206 U238 ( tN206 N238) vs. total Pb207 U235 ( tN207 N235). This modification permits the calculation of concordant ages for unaltered samples

  17. Uranium-Thorium evolution of extrasolar silicate worlds

    Science.gov (United States)

    Frank, Elizabeth A.; Mojzsis, Stephen J.

    2013-04-01

    nuclides generated by each process and then used the resulting proportions to constrain the heat they generate in a solar system given its age. Sensitivity tests indicate that of the constraints, the 235U/238U and 232Th/238U production ratios have the most significant effect on the results. By comparison, our predictions are relatively insensitive to the age of the galaxy. The 235U/238U production ratio is particularly fickle due to the relatively short half-life of 235U compared to 238U. For a galaxy age of 12.5 Gyr, the 235U/238U production ratio can only provide a minimum production ratio, found to be 1.42, whereas the allowable spectrum of the 232Th/238U production ratio is found to be 1.02 to 1.64, the higher values of which are consistent with published ratios. To ground-truth our model, we compared predicted Th/U ratios to published observations of ancient, metal-poor halo stars. Despite the wide error bars for the calculated ages of these stars due to observational limitations, our model predicts Th/U ratios consistent with observations. As such, in addition to making predictions for heat production in extrasolar systems, our model may also be used to constrain stellar ages.

  18. Variations in the uranium isotopic compositions of uranium ores from different types of uranium deposits

    Science.gov (United States)

    Uvarova, Yulia A.; Kyser, T. Kurt; Geagea, Majdi Lahd; Chipley, Don

    2014-12-01

    Variations in 238U/235U and 234U/238U ratios were measured in uranium minerals from a spectrum of uranium deposit types, as well as diagenetic phosphates in uranium-rich basins and peraluminous rhyolites and associated autunite mineralisation from Macusani Meseta, Peru. Mean δ238U values of uranium minerals relative to NBL CRM 112-A are 0.02‰ for metasomatic deposits, 0.16‰ for intrusive, 0.18‰ for calcrete, 0.18‰ for volcanic, 0.29‰ for quartz-pebble conglomerate, 0.29‰ for sandstone-hosted, 0.44‰ for unconformity-type, and 0.56‰ for vein, with a total range in δ238U values from -0.30‰ to 1.52‰. Uranium mineralisation associated with igneous systems, including low-temperature calcretes that are sourced from U-rich minerals in igneous systems, have low δ238U values of ca. 0.1‰, near those of their igneous sources, whereas uranium minerals in basin-hosted deposits have higher and more variable values. High-grade unconformity-related deposits have δ238U values around 0.2‰, whereas lower grade unconformity-type deposits in the Athabasca, Kombolgie and Otish basins have higher δ238U values. The δ234U values for most samples are around 0‰, in secular equilibrium, but some samples have δ234U values much lower or higher than 0‰ associated with addition or removal of 234U during the past 2.5 Ma. These δ238U and δ234U values suggest that there are at least two different mechanisms responsible for 238U/235U and 234U/238U variations. The 234U/238U disequilibria ratios indicate recent fluid interaction with the uranium minerals and preferential migration of 234U. Fractionation between 235U and 238U is a result of nuclear-field effects with enrichment of 238U in the reduced insoluble species (mostly UO2) and 235U in oxidised mobile species as uranyl ion, UO22+, and its complexes. Therefore, isotopic fractionation effects should be reflected in 238U/235U ratios in uranium ore minerals formed either by reduction of uranium to UO2 or chemical

  19. Using U-series Isotopes To Determine Sources Of Pedogenic Carbonates: Comparison Of Natural And Agricultural Soils In The Semi-arid Southern New Mexico And Western Texas

    Science.gov (United States)

    Nyachoti, S. K.; Ma, L.; Borrok, D. M.; Jin, L.; Tweedie, C. E.

    2012-12-01

    Pedogenic carbonates commonly precipitate from infiltrating soil water in arid and semi-arid lands and are observed in soils of southern New Mexico and western Texas. These carbonates could form an impermeable layer in the soil horizons impairing water infiltration, thus affecting crop growth and yield. It is important to determine the source of C and Ca in these carbonates and to understand conditions favoring their formation, kinetics and precipitation rates. In this study, major elements and U-series isotopes in bulk calcic soils, and weak acid leachates and residues were measured from one irrigated alfalfa site in the Hueco basin near El Paso, TX and one natural shrubland site on the USDA Jornada experimental range in southern NM. The combined geochemical and isotopic results allow us to determine the formation ages of the carbonates; investigate the mobility of U, Th, and major elements in these soils; and infer for the effects of irrigation on carbonate formation in agricultural soils. Our results show distinctive U and Th isotope systems in the two soil profiles analyzed. For example, (234U/238U) ratios in the Jornada bulk soils decrease from ~1.01 to 0.96 towards the surface, consistent with a preferential loss of 234U over 238U during chemical weathering. At the Jornada site, (238U/232Th) ratios decrease while (230Th/238U) increase towards the surface, consistent with a general depletion of U and the immobility of Th in the natural soils. By contrast at the Alfalfa site, (234U/238U) ratios of bulk soils increase from ~ 0.97 to 1.02 towards the surface, suggesting an additional source of external uranium, most likely the irrigation water from Rio Grande which has a (234U/238U) ratio of ~ 1.5 near El Paso. The (238U/232Th) and (230Th/238U) ratios also imply leaching of U from shallower soils but precipitation in greater depths at Alfalfa site; suggests that partial dissolution and re-precipitation of younger carbonates occur. Calculated carbonate ages from U

  20. The Effect of Redox Mechanisms on the Fractionation of Uranium `Stable' Isotopes

    Science.gov (United States)

    Kaltenbach, A.; Stirling, C. H.; Porcelli, D.; Hilton, D. R.; Kulongoski, J. T.

    2010-12-01

    Uranium is the heaviest naturally occurring element. It consists of three natural isotopes, 238U, 235U and 234U and has four oxidation states, U(III)-U(VI), of which only U(IV) and U(VI) are common. In the oxidized, hexavalent condition, U(VI) exists as uranyl ion (UO22+), which forms soluble, non-reactive complexes with carbonates. In the reduced condition, tetravalent U(IV) forms immobile minerals with hydroxides, fluorides and phosphates that are removed from the water column. In the recent years, isotopic fractionation between 235U and 238U has been detected in a range of terrestrial environments. Changes to U concentrations in natural waters occur due to biological uptake, adsorption/desorption to/from particulates and surfaces, diffusion into sediments, and chemically and biologically induced redox mechanisms (Swarzenski et al., 1999, Mar. Chem. 67, 181). The largest isotopic shifts evidently occur during the reduction of U(VI) to U(IV) in waters, during which precipitation changes the dissolved U concentration. However, the exact mechanisms controlling 235U/238U fractionation remain unclear. Some results implicate mass-dependent zero-point energy effects (preferential removal of 235U over 238U) (Rademacher et al., 2006, Environ. Sci. Technol. 40, 6943) as the main cause for the isotopic variations measured, while others suggest volume-dependent nuclear field shift effects (preferential removal of 238U over 235U) (Weyer et al., 2008, GCA 72, 345, Bopp et al., 2010, Environ. Sci. Technol. 44, 5927), which are predicted to be of the opposite sign and up to three times larger than mass-dependent effects. In this study, profiles of two different water masses were examined for their uranium concentration and their 235U/238U isotopic composition to determine the magnitude of the natural isotopic shifts as well as their origins. One set of samples was collected from a 160 m depth profile in the Framvaren Fjord, an anoxic basin. In this basin, the biogeochemical

  1. Precise and accurate measurement of U and Th isotopes via ICP-MS using a single solution

    Science.gov (United States)

    Mertz-Kraus, R.; Sharp, W. D.; Ludwig, K. R.

    2012-04-01

    U-series isotope measurements by ICP-MS commonly utilize separate runs for U and Th and standard-sample bracketing to determine correction factors for mass fractionation and ion counter yields. Here we present an approach where all information necessary to calculate an age (aside from background/baseline levels) is determined while analyzing a single solution containing both U and Th. This internally calibrated procedure should reduce any bias caused by distinct behavior of sample versus standard solutions during analysis and offers advantages including simplicity of operation, calculation of preliminary ages in real time, and simplified analysis of errors and their sources. Hellstrom (2003) developed a single-solution, internally-calibrated technique for an ICP-MS with multiple ion counters, but to our knowledge no such technique is available for an ICP-MS with a single ion counter. We use a Thermo Neptune Plus multi-collector ICP-MS with eight movable Faraday cups and a fixed center cup/ion counter equipped with a high abundance-sensitivity filter (RPQ). We use Faraday cups to measure all masses except 230 and 234, which are measured on the ion counter with the RPQ detuned (i.e., Suppressor voltage = 9950 V). 238U is maintained in a cup throughout the analysis to avoid reflections and is used to normalize signal instabilities related to sample introduction. Each analysis has a three-part structure, i.e. 1) background/baseline levels, 2) sample composition, and 3) peak-tails are sequentially determined. In step 1, multiplier dark noise/Faraday baselines plus background intensities at each mass are determined while aspirating running solution. During sample measurement in step 2, ion counter yields for Th and U are determined using signals of 300-400 kcps for 229Th and 233U by measuring 229Th/238U and 233U/238U ratios first with the minor masses on the ion counter and then with both masses in cups. Mass bias can be determined using the 233U/236U ratio of the spike

  2. Transportation and Power Requirements for He3 Mining of the Jovian Planets

    Science.gov (United States)

    Kammash, Terry; Tang, Ricky

    2008-01-01

    A bi-modal fusion propulsion system that can be used for transportation to and the mining of He3 from the Jovian planets is proposed. It consists of the Gasdynamic Mirror (GDM) fusion reactor which is analyzed for utilization as a propulsion device, as well as for use as a surface power system. The fusion reactions in the device are initiated by the heating provided by the fission fragments and the annihilation products produced by the ``at rest'' annihilation of antiprotons in uranium U238 target nuclei. The energetic pions and muons of the antiproton-proton (or neutron) annihilation in the U238 nucleus can heat a suitable fusion fuel to several keV temperature during their short lifetime, while the remaining heating to ignition is provided by the fission fragments. We examine the use of such a system to travel to Jupiter, for instance, to mine the He3 which is known to exist to the tune of 350 trillion tons in its atmosphere. Such a rich source of this isotope can readily meet the needs of a fusion-powered global industrial energy consumption estimated at 5400 tons annually, for an indefinite length of time. Although He3 exists to a much lesser degree in the lunar regolith, the power requirements for its extraction, estimated at 270 GJ per kg, may render its economic viability very much in question. It is suggested that mining the planets at a power requirement 30 times less than its lunar counterpart may be more desirable in spite of the distances involved, if a reasonably rapid transportation system can be devised. In its propulsive mode, the GDM device is shown to be capable of traveling to Jupiter and bringing back the annual world need of He3 in about six months. Based on such performance, it is quite reasonable to envision a space tanker employing the proposed propulsion system to fly from Earth to the outer planet of choice, spend a period of time in the planet's atmosphere extracting He3, or loading it from an extractor plant already in place, and then

  3. Tier II Analysis of Vadose Zone Sediments from UPRS 200-E-81 and 200-E-86

    Energy Technology Data Exchange (ETDEWEB)

    Valenta, Michelle M.; Geiszler, Keith N.; Bjornstad, Bruce N.; Schaef, Herbert T.; Brown, Christopher F.

    2009-04-01

    The overall goals of the Tank Farm Vadose Zone Project, led by Washington River Protection Solutions, are to define risks from past and future single-shell tank farm activities; identify and evaluate the efficacy of interim measures; and aid, via collection of geochemical information and data, the future decisions that must be made by the U.S. Department of Energy (DOE) regarding the near-term operations, future waste retrieval, and final closure activities for the single-shell tank waste management areas (WMAs). To meet the investigative goals of the Tank Farm Vadose Zone Project, the Environmental Sciences Laboratory performed geochemical analyses on vadose zone sediments collected within Waste Management Area C. Tier one analyses of UPR-200-E-86, which includes direct push probe holes C5952, C5958 and C5960, were performed between 3/25/08 and 4/14/08. Preliminary results were presented to CH2M Hill Hanford Group on 6/5/08. As a result of the tier one investigations, further tier two analyses were requested. Tier two investigations include particle size and mineralogy analyses on samples collected between 80 to 120 feet below ground surface that were found to contain high concentrations of chloride and sulfate. Tier one analyses on sediments retrieved near UPR-200-E-81, direct push probe hole C6394, were performed between 6/20/08 and 7/22/08. Preliminary results of the tier one analyses were presented on 8/15/08. As a result of the tier one investigations, further tier two analyses were requested. Tier two analyses include determining whether U-236 exists in samples at approximately 42 feet below the ground surface. Confirmation of U-236 will determine whether the U-238 seen in the leaches performed on samples at that depth is a result of contamination and not from leaching natural uranium. Using the water and acid extract U-238 concentrations from the tier one analysis, equilibrium Kd values were requested to be calculated. Additional tier two analysis includes

  4. Sediment residence times constrained by uranium-series isotopes: A critical appraisal of the comminution approach

    Science.gov (United States)

    Handley, Heather K.; Turner, Simon; Afonso, Juan C.; Dosseto, Anthony; Cohen, Tim

    2013-02-01

    Quantifying the rates of landscape evolution in response to climate change is inhibited by the difficulty of dating the formation of continental detrital sediments. We present uranium isotope data for Cooper Creek palaeochannel sediments from the Lake Eyre Basin in semi-arid South Australia in order to attempt to determine the formation ages and hence residence times of the sediments. To calculate the amount of recoil loss of 234U, a key input parameter used in the comminution approach, we use two suggested methods (weighted geometric and surface area measurement with an incorporated fractal correction) and typical assumed input parameter values found in the literature. The calculated recoil loss factors and comminution ages are highly dependent on the method of recoil loss factor determination used and the chosen assumptions. To appraise the ramifications of the assumptions inherent in the comminution age approach and determine individual and combined comminution age uncertainties associated to each variable, Monte Carlo simulations were conducted for a synthetic sediment sample. Using a reasonable associated uncertainty for each input factor and including variations in the source rock and measured (234U/238U) ratios, the total combined uncertainty on comminution age in our simulation (for both methods of recoil loss factor estimation) can amount to ±220-280 ka. The modelling shows that small changes in assumed input values translate into large effects on absolute comminution age. To improve the accuracy of the technique and provide meaningful absolute comminution ages, much tighter constraints are required on the assumptions for input factors such as the fraction of α-recoil lost 234Th and the initial (234U/238U) ratio of the source material. In order to be able to directly compare calculated comminution ages produced by different research groups, the standardisation of pre-treatment procedures, recoil loss factor estimation and assumed input parameter values

  5. Conceptual design of a large Spectral Shift Controlled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Matzie, R A; Menzel, G P

    1979-08-01

    Within the framework of the Nonproliferation Alternative Systems Assessment Program (NASAP), the US Department of Energy (DOE) has sponsored the development of a conceptual design of a large Spectral Shift Controlled Reactor (SSCR). This report describes the results of the development program and assesses the performance of the conceptual SSCR on the basis of fuel resource utilization and total power costs. The point of departure of the design study was a 1270 MW(e) PWR using Combustion Engineering's System 80/sup TM/ reactor and Stone and Webster's Reference Plant Design. The initial phase of the study consisted of establishing an optimal core design for both the once-through uranium cycle and the denatured U-235/thorium cycle with uranium recycle. The performance of the SSCR was then also assessed for the denatured U-233/thorium cycle with uranium recycle and for the plutonium/thorium cycle with plutonium recycle. After the optimal core design was established, the design of the NSSS and balance of plant was developed.

  6. Neutron- and proton-induced nuclear data evaluation of thorium, uranium and curium isotopes for energies up to 250 MeV

    CERN Document Server

    Young, Ouk Lee; Jonghwa, Chang; Konobeyev, A Yu

    2004-01-01

    The evaluation of neutron- and proton nuclear data for thorium-232, U-233,234,236, and Cm-243,244,245,246 isotopes have been performed at energies up to 250 MeV. Neutron data was evaluated at energies from 20 MeV to 250 MeV, and combined with the JENDL-3.3 data at 20 MeV while proton data was obtained for energies from 1 to 250 MeV. Nuclear model parameters are largely based on the IAEA-RIPL recommendation, and adjusted to better reproduce the available measurements. The coupled channel optical model was applied to calculate the total, reaction, elastic, and direct inelastic cross sections, and to obtain the transmission coefficients. Decay of excited nuclei was described with the Hauser-Feshbach and exciton models using the GNASH code to simultaneously handle neutron, proton, deuteron, triton, helium-3, alpha , gamma emissions and fissions. Special attention was paid on the fission cross sections for energies where experimental data are scant, using appropriate systematics and fittings. Particles and gamma e...

  7. Additional Information for E-Area Vault Performance Assessment, Appendix I `Suspect Soil Performance` - Results of Modeling the Effects of Organic Matter on the Mobility of Radionuclides as it Relates to the Disposal of Wood Products in E-Area Slit Trenches

    Energy Technology Data Exchange (ETDEWEB)

    Serkiz, S.M. [Westinghouse Savannah River Company, AIKEN, SC (United States); Myers, J.L.

    1996-04-24

    Numerous laboratory and field studies have shown that the chemical form (i.e., speciation) of many metals and radionuclides is affected by the presence of naturally occurring organic matter (OM) and its degradation products. The effects of OM (e.g., wood products) on the speciation and, therefore, the mobility of Am, Bk, Cf, Cm, Cs, Ni, NpO{sub 2}, Rb, Sr. UO{sub 2}, and Zr were estimated through use of geochemical and groundwater flow modeling. Due to the complex mixture nature of naturally occurring OM, the OM system was simplified through use of surrogate compounds (citric acid and ethylenedinitrilotetraacetic acid (EDTA)) to estimate effects of OM on radionuclide mobility. Using this approach, OM was found to have no effect on the inventory limits for Cs, NpO{sub 2}, Rb and Zr. The inventory limits for the isotopes of Am, Bk, Cf, Cm, Ni, Pd, PuO{sub 2}, Sr, and UO{sub 2} calculated in the presence of OM decreased over a range of 26 percent for U-233 to 48 percent for Pu-240. The information in this report will be included in the next revision of the E-Area Vaults Performance Assessment.

  8. The Spallator and APEX Nuclear Fuel Cycle a New Option for Nuclear Power

    Science.gov (United States)

    Steinberg, M.

    1983-02-01

    A new nuclear fuel cycle is described which provides a long term supply of nuclear fuel for the thermal LWR nuclear power reactors and eliminates the need for long-term storage of radioactive waste. Fissile fuel is produced by the Spallator which depends on the production of spallation neutrons by the interaction of high energy (1 to 2 GeV) protons on a heavy metal target. The neutrons are absorbed in a surrounding natural uranium or thorium blanket in which fissile Pu-239 or U-233 is produced. Advances in linear accelerator technology makes it possible to design and construct a high beam current continuous wave proton linac for production purposes. The target is similar to a sub-critical reactor and produces heat which is converted to electricity for supplying the linac. The Spallator is a self-sufficient fuel producer, which can compete with the fast breeder. The APEX fuel cycle depends on recycling the transuranics and long-lived fission products while extracting the stable and short-lived fission products when reprocessing the fuel. Transmutation and decay within the fuel cycle and decay of the short-lived fission products external to the fuel cycle eliminates the need for long-term geological age storage of fission product waste.

  9. Using Uranium-series isotopes to understand processes of rapid soil formation in tropical volcanic settings: an example from Basse-Terre, French Guadeloupe

    Science.gov (United States)

    Ma, Lin

    2015-04-01

    Lin Ma1, Yvette Pereyra1, Peter B Sak2, Jerome Gaillardet3, Heather L Buss4 and Susan L Brantley5, (1) University of Texas at El Paso, El Paso, TX, United States, (2) Dickinson College, Carlisle, PA, United States, (3) Institute de Physique d Globe Paris, Paris, France, (4) University of Bristol, Bristol, United Kingdom, (5) Pennsylvania State University Main Campus, University Park, PA, United States Uranium-series isotopes fractionate during chemical weathering and their activity ratios can be used to determine timescales and rates of soil formation. Such soil formation rates provide important information to understand processes related to rapid soil formation in tropical volcanic settings, especially with respect to their fertility and erosion. Recent studies also highlighted the use of U-series isotopes to trace and quantify atmospheric inputs to surface soils. Such a process is particularly important in providing mineral nutrients to ecosystems in highly depleted soil systems such as the tropical soils. Here, we report U-series isotope compositions in thick soil profiles (>10 m) developed on andesitic pyroclastic flows in Basse-Terre Island of French Guadeloupe. Field observations have shown heterogeneity in color and texture in these thick profiles. However, major element chemistry and mineralogy show some general depth trends. The main minerals present throughout the soil profile are halloysite and gibbsite. Chemically immobile elements such as Al, Fe, and Ti show a depletion profile relative to Th while elements such as K, Mn, and Si show a partial depletion profile at depth. Mobile elements such as Ca, Mg, and Sr have undergone intensive weathering at depths, and an addition profile near the surface, most likely related to atmospheric inputs. (238U/232Th) activity ratios in one soil profile from the Brad David watershed in this study ranged from 0.374 to 1.696, while the (230Th/232Th) ratios ranged from 0.367 to 1.701. A decrease of (238U/232Th) in the

  10. Long-Term Slip Rate on the Southern San Andreas Fault Determined by Th-230/U Dating of Pedogenic Carbonate.

    Science.gov (United States)

    Fletcher, K. E.; Johnson, G.; Kendrick, K. J.; Hudnut, K. W.; Sharp, W. D.

    2006-12-01

    Determinations of long-term slip rates are limited, in part, by our ability to accurately estimate the age of offset landforms. U-series dating on pedogenic carbonate provides a relatively novel way of dating landforms, with strengths that complement more widely applied cosmogenic (CRN) techniques. We present new Th-230/U dates for pedogenic carbonate coatings on pebbles of the Biskra Palms fan, near Indio, California, which is offset by the southern San Andreas fault. Small, carefully chosen samples of dense pedogenic carbonate analyzed by mass spectrometry, have 3-10 ppm uranium and low common thorium (Th-232), making them highly favorable for U-series dating. Only minor corrections for initial Th-230 are necessary, and are made using Th-232 as an index isotope with propagation of uncertainties. Samples of early-formed carbonate collected from depths of about 2 m in fan soils typically consist of dense coatings 200-500 microns thick. Such coatings from 6 pebbles from 3 different locations within the fan yield apparent ages between 30 ± 2 ka and 46 ± 2 ka (all errors 2 sigma), with a median age of 38.4 ka (n= 11). Each age averages over the sampled interval of coating growth, hence the spread of ages reflects clast-to-clast variation in coating accumulation rates. All ages are therefore minimum ages for the stabilization of the fan because the time lag between stabilization and carbonate pedogenesis at Biskra Palms is, as yet, unknown. Sub-samples of individual clast-coatings yield ages in good agreement-- e.g., 45.0 ± 0.8 ka, 46.0 ± 1.8 ka, 44.8 ± 1.0 ka, 45.7 ± 0.9 ka (MSWD = 0.88), demonstrating closed U-Th systems. Van der Woerd et al (2006) reported an average CRN age of 35.5 ± 2.5 ka for the fan surface and an offset of 565 ± 80 m, for a slip rate of 15.9 ± 3.4 mm/a. Using their offset, and our oldest mean age of 45.3 ± 0.5 Ma (n=4, ages above) as the minimum landform age, we estimate a maximum slip rate of 12.5 ± 1.8 mm/a. This maximum average

  11. Recycling of crystal mush-derived melts and short magma residence times revealed by U-series disequilibria at Stromboli volcano

    Science.gov (United States)

    Bragagni, Alessandro; Avanzinelli, Riccardo; Freymuth, Heye; Francalanci, Lorella

    2014-10-01

    The presence of crystal mushes in the feeding system of active volcanoes is generally revealed by antecrysts, representing the crystalline portion of old magmas recycled in the juvenile material, but very little is known about the fate of interstitial liquid hosted within the crystal-rich mush (i.e. antemelt). U-series disequilibria measured in magmas erupted in the past 18 years at Stromboli volcano provide the first geochemical evidence of the involvement of antemelt and help constraining the timescales of the processes occurring in the plumbing system of the volcano. Despite almost constant major and trace element composition, significant variations in isotope ratios are observed. (230Th/232Th) decreases with time, whilst (238U/232Th), (226Ra/230Th) and 87Sr/86Sr are different in the two types of magma erupted. Magma with low phenocryst content (lp) is erupted as pumices during paroxysm and is thought to belong to a deep reservoir. Highly porphyritic magma (hp) is erupted during the normal ;Strombolian; activity as scoria and during the effusive events as lavas, and it is considered to derive from the former one within a shallow reservoir through degassing-driven crystallisation, mixing and incorporation of antecrysts. The distinct (238U/232Th) of lp and hp magma requires the involvement of a component with high 87Sr/86Sr and (238U/232Th) deriving from older magmas erupted earlier in the volcano history (up to 2.5 ka). The incompatibility of U and Th in major mineral phases limits the possible effect of antecrysts, hence requiring the involvement of a U- and Th-rich antemelt. The decrease of 226Ra-excess from lp to hp magmas provides further and independent evidence for the involvement of a few thousands years old antemelt. The variation with time of (230Th/232Th) within lp and hp magmas is exploited to constrain the residence time of magmas in the deep and shallow reservoir of the volcano to < 55 yrs (inferred reservoir volume < 0.5 km3) and 2-10 yrs (inferred

  12. 230Th/U dating of Last Interglacial brain corals from Bonaire (southern Caribbean) using bulk and theca wall material

    Science.gov (United States)

    Obert, J. Christina; Scholz, Denis; Felis, Thomas; Brocas, William M.; Jochum, Klaus P.; Andreae, Meinrat O.

    2016-04-01

    We compared the suitability of two skeletal materials of the Atlantic brain coral Diploria strigosa for 230Th/U-dating: the commonly used bulk material comprising all skeletal elements and the denser theca wall material. Eight fossil corals of presumably Last Interglacial age from Bonaire, southern Caribbean Sea, were investigated, and several sub-samples were dated from each coral. For four corals, both the ages and the activity ratios of the bulk material and theca wall agree within uncertainty. Three corals show significantly older ages for their bulk material than for their theca wall material as well as substantially elevated 232Th content and (230Th/238U) ratios. The bulk material samples of another coral show younger ages and lower (230Th/238U) ratios than the corresponding theca wall samples. This coral also contains a considerable amount of 232Th. The application of the available open-system models developed to account for post-depositional diagenetic effects in corals shows that none of the models can successfully be applied to the Bonaire corals. The most likely explanation for this observation is that the assumptions of the models are not fulfilled by our data set. Comparison of the theca wall and bulk material data enables us to obtain information about the open-system processes that affected the corals. The corals showing apparently older ages for their bulk material were probably affected by contamination with a secondary (detrital) phase. The most likely source of the detrital material is carbonate sand. The higher (230Th/232Th) ratio of this material implies that detrital contamination would have a much stronger impact on the ages than a contaminant with a bulk Earth (230Th/232Th) ratio and that the threshold for the commonly applied 232Th reliability criterion would be much lower than the generally used value of 1 ng g-1. The coral showing apparently younger ages for its bulk material was probably influenced by more than one diagenetic process. A

  13. Measurement of natural radioactivity in Chahbahar – Sistan and Blouchestan in Iran

    Directory of Open Access Journals (Sweden)

    Seyyed Abbas Hosseini

    2014-05-01

    Full Text Available Background: Natural radioactivity exposes radiation so that it goes whole body through different ways and causes diseases leading to death, if it is more than standard amount by ICRP. The aim of this study was to measure the amount of radioactivity in the soil, water and air of Chabahar city in Sistan and Baluchestan province, Iran. Material and Methods: A few locations of city were chosen as a sampling station. The study of drinking water radioactivity was performed in Bandargah and city square. Soil’ radioactivity tested in Tiss village and Shillat. Radioactivity measurement of air was performed in the above-mention places. The radioactivity of drinking water and soil were measured by using a coaxial detector Germanium with high purity. Results: Average concentrations of Ra-228, Th-222 and K-40 in soil and Ra-228 in piping drinking water and in consumed plant were 450±34.5 Bq/Kg, 28.5±2.5 Bq/Kg, 24.3±2.6 Bq/Kg and <2 Bq/L, respectively. The overall results demonstrated low levels of radioactivity (<2 mBq/L, and less levels of K-40, Ra-228 and Th-232 in soil. The Ra-228 concentrations measured in piping and underground water were generally below the detection limit. As there was lower radioactivity in comparison with international standards, there was not probably any disease. Absorbed dose in air was 485.5±20 nanoGy/h and effective dose was 596±24.5, 5 µSv. Conclusion: It is found that there is a significant difference in average of 228Ra, 40K and 232Th in the area relative to some points in the world that may be because of organic matter and microbial biomass. Different factors effect on radioactivity of samples. This region shows the least ionizing radiation.

  14. Radionuclide distribution of Holocene sediments and its effects on the habitat of recent foraminifers: A case study from the Western Marmara Sea (Turkey)

    Science.gov (United States)

    Ünal Yumun, Zeki; Kam, Erol; Murat Kılıc, Ali

    2017-04-01

    ABSTRACT Radionuclides cause radioactive contamination in aquatic environments just as other non-biodegradable pollutants, such as heavy metals, sink to the seafloor and accumulate in the sediments. These radioactive pollutants especially affect benthic foraminifera living on the sediment surface or in the sediments in the seafloor. Foraminifera were used as bioindicators to analyze the effect of radioactivity pollution on ecosystems. In this study, we have investigated natural and artificial radionuclide (232Th, 226Ra, 40K and 137Cs) distribution in sediment samples taken in the living areas of benthic foraminifera in the Western Marmara Sea by means of gamma spectrometry. Accordingly, 29 core samples taken in 2016 from depths of about 20-35 m close to the shores of the Marmara Sea were used. Core samples representing the pollution of the study area were collected at locations such as discharge points for domestic and industrial areas, port locations, and others. Other samples were taken from areas unaffected or less affected by pollution. The radionuclide concentration activity values in the sediment samples obtained from the locations, in Bq/kg, were 137Cs, 0.9-9.4; 232Th, 18.9-86; 226Ra, 10-50; 40K, 24.4-670. These values were compared with the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) data, and an environmental analysis was carried out. The 226Ra series, the 232Th series, and the 40K radionuclides accumulate naturally, and they are also increasing continuously due to anthropogenic pollution. Although the 226Ra values obtained throughout the study areas remained within normal limits according to the UNSCEAR values, the 40K and 232Th series values were found to be higher in almost all locations. According to these results, the main causes of radioactive pollution in the investigation area are agricultural and mining activities. Keywords: Ra-226, Th-232, K-40, Cs-137, radionuclide, Western Marmara Sea, Foraminifera

  15. Niger River Discharge and the Connection to the West African Monsoon Over the Last 25 kyr

    Science.gov (United States)

    Patten, J.; Marcantonio, F.; Slowey, N. C.; Schmidt, M. W.; Parker, A. O.; Thomas, D. J.

    2016-12-01

    The intensity of the West African monsoon is directly tied to the shifting of the Inter-Tropical Convergence Zone and global-scale climate variability. As the West African monsoon varies through time, it affects the precipitation that occurs within the Niger River basin and the Niger River's discharge into the eastern equatorial Atlantic Ocean. The accumulation of marine sediments on the continental slope offshore of the Niger Delta reflects these processes. We seek to better understand how related environmental processes have varied as climate and sea level changed during the latter part of the last glacial-interglacial cycle. Here we present results from our ongoing investigation of sediments collected offshore of the Niger Delta that reflect such changes. The concentrations of 230Th, 232Th, and 234U in the sediments have been measured and combined with ages from radiocarbon dates and planktonic foraminiferal δ18O stratigraphies to estimate how the rate of sediment accumulation has varied through time. This record is considered together with measurements of sediment CaCO3 content and grain-size distribution to better understand the relative importance of environmental processes that control the flux of sediments and thorium to the seafloor - scavenging by particles settling through the water column versus the transport of sediments downslope by turbidity flows. We present xs230Th-derived 232Th fluxes that we suggest approximate the amount of fine-grained detrital material delivered from the Niger River to our sites. We anticipate that the importance of these competing processes will vary as climate/sea-level change influences the flux of sediments from the Niger River and the transport of these sediments to the slope.

  16. Natural radioactivity content in groundwater of Mt. Etna’s eastern flank and gamma background of surrounding rocks.

    Directory of Open Access Journals (Sweden)

    Beata Kozłowska

    2016-02-01

    Full Text Available Waters of Mt. Etna are the main source of drinking water for the local population and are also distributed in municipal supply systems to neighbouring areas. Radioactivity in underground waters and surrounding rocks from the eastern flank of Mt.Etnawas investigated on the basis of 9 water and 8 rocks samples from 12 localities altogether. Three samples were from water drainage galleries and six from water wells. All water intakes are used for consumption. Activity concentration of uranium isotopes 234,238U, radium isotopes 226,228Ra and radon 222Rn were determined with the use different nuclear spectrometry techniques. The determination of uranium isotopes was carried out with the use of alpha spectrometry. The measurements of radium and radon activity concentration in water were performed with the use of a liquid scintillation technique. Additionally, rocks surrounding the intakes were examined with gamma spectrometry. All water samples showed uranium concentration above Minimum Detectable Activity (MDA, with the highest total uranium (234U + 238U activity concentration equal to 149.2±6 mBq/L. Conversely, all samples showed radium isotopes activity concentrations below MDA. Radon activity concentration was within the range from 2.91±0.36 to 21.21±1.10 Bq/L, hence these waters can be classified as low – radon waters. Gamma natural background of the rocks surrounding the water sampling sites was found on the same levels as other volcanic rocks of Italy.

  17. Final report: survey and removal of radioactive surface contamination at environmental restoration sites, Sandia National Laboratories/New Mexico. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, K.A.; Mitchell, M.M. [Brown and Root Environmental, Albuquerque, NM (United States); Jean, D. [MDM/Lamb, Inc., Albuquerque, NM (United States); Brown, C. [Environmental Dimensions, Inc., Albuquerque, NM 87109 (United States); Byrd, C.S. [Sandia National Labs., Albuquerque, NM (United States)

    1997-09-01

    This report describes the survey and removal of radioactive surface contamination at Sandia`s Environmental Restoration (ER) sites. Radiological characterization was performed as a prerequisite to beginning the Resource Conservation and Recovery Act (RCRA) corrective action process. The removal of radioactive surface contamination was performed in order to reduce potential impacts to human health and the environment. The predominant radiological contaminant of concern was depleted uranium (DU). Between October 1993 and November 1996 scanning surface radiation surveys, using gamma scintillometers, were conducted at 65 sites covering approximately 908 acres. A total of 9,518 radiation anomalies were detected at 38 sites. Cleanup activities were conducted between October 1994 and November 1996. A total of 9,122 anomalies were removed and 2,072 waste drums were generated. The majority of anomalies not removed were associated with a site that has subsurface contamination beyond the scope of this project. Verification soil samples (1,008 total samples) were collected from anomalies during cleanup activities and confirm that the soil concentration achieved in the field were far below the target cleanup level of 230 pCi/g of U-238 (the primary constituent of DU) in the soil. Cleanup was completed at 21 sites and no further radiological action is required. Seventeen sites were not completed since cleanup activities wee precluded by ongoing site activity or were beyond the original project scope.

  18. Comparative study of X-ray emission from plasma focus relative to different preionization schemes

    Science.gov (United States)

    Ahmad, S.; Qayyum, A.; Hassan, M.; Zakaullah, M.

    2017-07-01

    A 2.7-kJ Mather-type plasma focus has been investigated for X-ray emission with preionization produced by an α-source, a β-source, and a shunt resistor. Time-resolved and time integrated measurements are carried out using a PIN-diode-based X-ray spectrometer and pinhole camera. The β-source (28Ni63) assisted preionization enhances the X-ray emission up to 25%, while preionization induced by depleted uranium (92U238) increases both Cu-Kα and total X-ray yield of about 100%. The preionization caused by the optimum shunt resistor enhances the Cu-Kα and total X-ray yield of about 53%. It is found that preionization also broadens the working pressure range for the high X-ray yield and improves the shot-to-shot reproducibility of the system. Pinhole images reveal that the X-ray emission from the anode tip is dominant owing to impact of electron bombardment, while the X-ray emission from hot spots is also visible.

  19. Performance-assessment progress for the Rozan low-level waste disposal facility

    Energy Technology Data Exchange (ETDEWEB)

    Smietanski, L.; Mitrega, J.; Frankowski, Z. [Polish Geological Institute, Warsaw (Poland)] [and others

    1995-12-31

    The paper presents a condensed progress report on the performance assessment of Poland`s low-level waste disposal facility which is operating since 1961. The Rozan repository is of near-surface type with facilities which are the concrete fortifications built about 1910. Site characterization activities supplied information on regional geology, geohydrology, climatic and hydrologic conditions and terrain surface evolution due to geodynamic processes. Field surveys enabled to decode lithological, hydrogeological and geochemical site specific conditions. From the laboratory tests the data on groundwater chemistry and soil geochemical and hydraulic characteristics were obtained. The site geohydrologic main vulnerable element is the upmost directly endangered unconfined aquifer which is perched in relation to the region-wide hydraulic system. Heterogeneity of this system reflects in a wide range of hydraulic conductivity and thickness variations. It strongly affects velocity and flow directions. The chemistry of groundwater is unstable due to large sensitivity to external impacts. Modeling of the migration of the critical long-lived radionuclides Tc-99, U-238 and Pu-239 showed that the nearly 20 m thick unsaturated zone plays crucial role as an effective protective barrier. These radionuclides constitute minor part of the total inventory. Modeling of the development of the H-3 plume pointed out the role the macrodispersion plays in the unsaturated zone beneath the repository.

  20. Results Assessment of Intercomparison Exercise CSN/CIEMAT-2013 among Spanish National Laboratories of Environmental Radioactivity (Air); Evaluación de la Intercomparación CSN/CIEMAT-2013 entre los Laboratorios Nacionales de Radiactividad Ambiental (Aire)

    Energy Technology Data Exchange (ETDEWEB)

    Trinidad, J. A.; Gascó, C.; Llauradó, M.

    2015-07-01

    This report describes the results assessment of the intercomparsion exercise among environmental radioactivity laboratories, organised by Spanish Regulatory Institution (CSN) and prepared and evaluated by UB and CIEMAT respectively. The exercise has been carried out following the international standards ISO-43 and ISO/IUPAC that provide a useful guide to perform proficiency tests and inter-laboratories comparisons. The selected matrix for this year (2013) was filters, which was enriched with artificial radionuclides (137Cs, 60Co and 57Co) and contained natural radionuclides (234U, 238U, U-natural 230Th, 226Ra, 210Pb, 234Th, 214Bi and 214Pb) at environmental level of activity concentration. Three commonly used filters (47 mm diameter, 44x44 cm2 and 20x25 cm2) were prepared. Two 47 mm diameter filter were prepared to separate 226Ra and 210Pb analysis. The z-score test was applied to determine how much the laboratories differ from the reference value. The reference value for this exercise was the median of the results from the different laboratories and their standard deviations to achieve a more complete and objective study of the laboratories performance. The participant laboratories have demonstrated a satisfactory quality level for measuring the natural and artificial radionuclides content in this matrix. The study has showed a homogeneous behaviour of the laboratories.

  1. Isotopic tracers of paleohydrologic change in large lakes of the Bolivian Altiplano

    Science.gov (United States)

    Placzek, Christa J.; Quade, Jay; Patchett, P. Jonathan

    2011-01-01

    We have developed an 87Sr/ 86Sr, 234U/ 238U, and δ 18O data set from carbonates associated with late Quaternary paleolake cycles on the southern Bolivian Altiplano as a tool for tracking and understanding the causes of lake-level fluctuations. Distinctive groupings of 87Sr/ 86Sr ratios are observed. Ratios are highest for the Ouki lake cycle (120-95 ka) at 0.70932, lowest for Coipasa lake cycle (12.8-11.4 ka) at 0.70853, and intermediate at 0.70881 to 0.70884 for the Salinas (95-80 ka), Inca Huasi (~ 45 ka), Sajsi (24-20.5 ka), and Tauca (18.1-14.1 ka) lake cycles. These Sr ratios reflect variable contributions from the eastern and western Cordilleras. The Laca hydrologic divide exerts a primary influence on modern and paleolake 87Sr/ 86Sr ratios; waters show higher 87Sr/ 86Sr ratios north of this divide. Most lake cycles were sustained by slightly more rainfall north of this divide but with minimal input from Lake Titicaca. The Coipasa lake cycle appears to have been sustained mainly by rainfall south of this divide. In contrast, the Ouki lake cycle was an expansive lake, deepest in the northern (Poópo) basin, and spilling southward. These results indicate that regional variability in central Andean wet events can be reconstructed using geochemical patterns from this lake system.

  2. Behavior and environmental impacts of radionuclides during the hydrometallurgy of calcareous and argillaceous rocks, southwestern Sinai, Egypt.

    Science.gov (United States)

    El Aassy, Ibrahim E; Nada, Afaf A; El Galy, Mohamed M; El Feky, Mohamed G; Abd El Maksoud, Thanaa M; Talaat, Shadia M; Ibrahim, Eman M

    2012-06-01

    The hydrometallurgy of radionuclides means getting the radioelements from the rocks into solution by leaching, getting the radionuclides from the solution by extraction process, and then precipitation of the desired elements to obtain concentrate. The follow-up of the radionuclides during these processes is the main target of this work to identify the identity of the original samples, pregnant solutions (leachates), residuals and the concentrate. Six samples were chosen to achieve this work. The leaching process was carried out under the conditions; 20-30% acid (H(2)SO(4)) concentration, 1:3 solid/liquid ratios, 60 min stirring time at room temperature. The activity concentrations of (238)U, (235)U, (234)U, (226)Ra, (214)Pb, (214)Bi, (232)Th and (40)K were measured in the original samples, residuals and U-concentrate (Bq/kg), and leachates (Bq/ℓ). The results indicate that, the radionuclides before (226)Ra in the (238)U decay series are more leachable (released) than those from (226)Ra to (214)Bi in the order; (234)U>(238)U=(235)U > (226)Ra>(214)Pb>(214)Bi. (232)Th and (40)K are immobile under the present conditions. The radiological hazards of natural radioactivity in the original samples, leachates, residuals and U-concentrate were calculated and compared with the internationally recommended values and were found to be much higher than the world average values. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Transuranic contaminated waste functional definition and implementation

    Energy Technology Data Exchange (ETDEWEB)

    Kniazewycz, B.G.

    1980-03-01

    The purpose of this report is to examine the problem(s) of TRU waste classification and to document the development of an easy-to-apply standard(s) to determine whether or not this waste package should be emplaced in a geologic repository for final disposition. Transuranic wastes are especially significant because they have long half-lives and some are rather radiotoxic. Transuranic radionuclides are primarily produced by single or multiple neutron capture by U-238 in fuel elements during the operation of a nuclear reactor. Reprocessing of spent fuel elements attempts to remove plutonium, but since the separation is not complete, the resulting high-activity liquids still contain some plutonium as well as other transuranics. Likewise, transuranic contamination of low-activity wastes also occurs when the transuranic materials are handled or processed, which is primarily at federal facilities involved in R and D and nuclear weapons production. Transuranics are persistent in the environment and, as a general rule, are strongly retained by soils. They are not easily transported through most food chains, although some reconcentration does take place in the aquatic food chain. They pose no special biological hazard to humans upon ingestion because they are weakly absorbed from the gastrointestional tract. A greater hazard results from inhalation since they behave like normal dust and fractionate accordingly.

  4. Studies of Limits on Uncontrolled Heavy Ion Beam Losses for Allowing Hands-On Maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Reginald M. Ronningen; Igor Remec

    2010-09-11

    Dose rates from accelerator components activated by 1 W/m beam losses are obtained semiempirically for a 1 GeV proton beam and by use of Monte Carlo transport codes for the proton beam and for 777 MeV/u 3He, 500 MeV/u 48Ca, 86Kr, 136Xe, and 400 MeV/u 238U ions. The dose rate obtained by the semi-empirical method, 0.99 mSv/h (99 mrem/h) at 30 cm, 4 h after 100 d irradiation by a 1-GeV proton beam, is consistent with studies at several accelerator facilities and with adopted hands-on maintenance dose rate limits. Monte Carlo simulations verify this result for protons and extend studies to heavy ion beam losses in drift-tube linac and superconducting linac accelerating structures. The studies indicate that the 1 W/m limit imposed on uncontrolled beam losses for high-energy proton beams might be relaxed for heavy ion beams. These studies further suggest that using the ratio of neutrons produced by a heavy ion beam to neutrons produced by a proton beam along with the dose rate from the proton beam (for thin-target scenarios) should allow an estimate of the dose rates expected from heavy ion beam losses.

  5. Covariance generation and uncertainty propagation for thermal and fast neutron induced fission yields

    Science.gov (United States)

    Terranova, Nicholas; Serot, Olivier; Archier, Pascal; De Saint Jean, Cyrille; Sumini, Marco

    2017-09-01

    Fission product yields (FY) are fundamental nuclear data for several applications, including decay heat, shielding, dosimetry, burn-up calculations. To be safe and sustainable, modern and future nuclear systems require accurate knowledge on reactor parameters, with reduced margins of uncertainty. Present nuclear data libraries for FY do not provide consistent and complete uncertainty information which are limited, in many cases, to only variances. In the present work we propose a methodology to evaluate covariance matrices for thermal and fast neutron induced fission yields. The semi-empirical models adopted to evaluate the JEFF-3.1.1 FY library have been used in the Generalized Least Square Method available in CONRAD (COde for Nuclear Reaction Analysis and Data assimilation) to generate covariance matrices for several fissioning systems such as the thermal fission of U235, Pu239 and Pu241 and the fast fission of U238, Pu239 and Pu240. The impact of such covariances on nuclear applications has been estimated using deterministic and Monte Carlo uncertainty propagation techniques. We studied the effects on decay heat and reactivity loss uncertainty estimation for simplified test case geometries, such as PWR and SFR pin-cells. The impact on existing nuclear reactors, such as the Jules Horowitz Reactor under construction at CEA-Cadarache, has also been considered.

  6. Pathways analysis and radiation-dose estimates for radioactive residues at formerly utilized MED/AEC sites

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, T.L.; Chee, P.C.; Knight, M.J.; Peterson, J.M.; Roberts, C.J.; Robinson, J.E.; Tsai, S.Y.H.; Yuan, Y.C.

    1983-03-01

    Methods of analysis are developed for estimating the largest individual radiation dose that could result from residual radioactivity at sites identified by the Formerly Utilized Sites Remedial Action Program (FUSRAP) of the US Department of Energy. Two unique aspects of the methods are (1) a systematic structuring of the radiation pathways analysis into source terms, source-to-exposure analysis, and exposure-to-dose analysis, and (2) the systematic use of data on the average concentrations of naturally occurring radionuclides in soil, food, and the human body in order to assess the validity of model calculations and obtain more realistic values. The methods are applied to a typical FUSRAP site in order to obtain generic source-to-dose (D/S) conversion factors for estimating the radiation dose to the maximally exposed individual from a known concentration of radionuclides in the soil. The D/S factors are used to derive soil guidelines, i.e., the limiting concentrations of radionuclides at a typical FUSRAP site that are unlikely to result in individual dose limits that exceed generally accepted radiation protection standards. The results lead to the conclusion that the soil guidelines should not exceed 17, 75, and 300 pCi/g for Ra-226, U-238, and Th-230, respectively.

  7. Simplified dynamic simulation of a traveling wave nuclear reactor; Simulacion dinamica simplificada de un reactor nuclear de onda viajera

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez M, H.; Espinosa P, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Area de Ingenieria en Recursos Energeticos, San Rafael Atlixco No. 186, Col. Vicentina, 09340 Ciudad de Mexico (Mexico); Francois, J. L. [UNAM, Facultad de Ingenieria, Paseo Cuauhnahuac 8532, Jiutepec 62550, Morelos (Mexico); Lopez S, R., E-mail: heribertosanchez7@hotmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2016-09-15

    In this work the nuclear fuel burn wave in a fast traveling wave reactor (TWR) is presented, using the reduced model of the neutron diffusion equation, considering only the axial component, and the equations of the transuranic dynamics of U-Pu and a radionuclide of Pu. Two critical zones of the reactor are considered, one enriched with U-Pu called ignition zone and the other impoverished zone or of U-238, named breeding zone. Occupying Na as refrigerant within TWR, and Fe as structural material; both are present in the ignition and breeding zones. Considering as a fissile material the Pu, since by neutron capture the U is transformed into Pu, thus increasing the quantity of Pu more than that of U; in this way the fuel burn stability with the wave dynamics is understood. The calculation of the results was approached numerically to determine the temporal space evolution of the neutron flux in this system and of the main isotopes involved in the burning process. (Author)

  8. The design of a source to simulate the gamma-ray spectrum emitted by a radioisotope thermoelectric generator

    Science.gov (United States)

    Reier, M.

    1972-01-01

    A simulated source was designed to duplicate the gamma spectrum of a uniform cylindrical 2200-watt Pu02 radioisotope thermoelectric generator containing 81% Pu-238 and 1.2 ppm Pu-236. Gamma rays from the decay of Pu-238, Am-241, Pu-239, and the 0-18(alpha,n)Ne-21 reaction were catalogued in broad energy groups. Two 46- and one 22-mc Th-228 sources provided simulation at various times in the life of the fuel capsule up to 18 years, which covers the time span of an outer planet mission. Emission from Th-228 represents the overwhelming contribution of the gamma spectrum after the first few years. The sources, in the form of 13-inch rods, were placed in a concentric hole in a cylinder of depleted uranium, which provided shielding equivalent to the self-shielding of the fuel capsule. The thickness of the U-238 cylinder (0.55cm) was determined by Monte Carlo calculations to insure that the spectrum emerging from the simulated source matched that of the fuel capsule.

  9. Photonuclear cross sections of Pu-239 using neutron capture gamma rays, near threshold

    Science.gov (United States)

    Antonio, Marco; de Moraes, P. V.; Cesar, Marilia F.

    1993-04-01

    The photofission and photoneutron cross sections of Pu-239 have been measured by using monochromatic and discrete photons produced by thermal neutron capture gamma rays in several targets placed at the core of the IEA-R1 reactor in the energy interval from 5.43 MeV to 9.72 MeV. Analysing the photofission and photoneutron data we have observed similarities between the cross sections obtained for Pu-239 in comparison with the data obtained by other authors. From the photofission cross sections obtained and according to the liquid drop model, the height of the simple fission barrier was determined: F.B. = (5.7 ± 0.2) MeV. The relative fissionability to U-238 was also determined and shown to be energy independent: F.R. = (3.32 ± 0.41). For the competition between the photoneutron and the photofission emission (Γn/Γf) a constant value was found: (0.44 ± 0.05). By using this result the following nuclear temperature for Pu-239 was determined on basis of Nuclear Constant Temperature model of level density: T = (0.49 ± 0.05) MeV. The total photoabsorption cross sections were calculated as well as the photofission branching ratio (Γf/ΓA), or fission probability Pf. A constant value was also found: Pf = (0.70 ± 0.06).

  10. The Oklo natural reactors - Cumulative fission yields and nuclear characteristics of Reactor Zone 9

    Science.gov (United States)

    Loss, R. D.; de Laeter, J. R.; Rosman, K. J. R.; Benjamin, T. M.; Curtis, D. B.

    1988-07-01

    The isotopic composition of Mo, Ru, Pd, Ag, Cd, Sn, Te, Nd, and U have been measured by solid source mass spectrometry in eight uraninite samples from Reactor Zone 9 at the Oklo natural reactors. Cumulative fission yields for most of these elements have been derived after correcting for the primordial component of the element concerned. Neutron capture reactions on a number of nuclides with significant thermal cross sections, and fission chains in which one of the precursor nuclides has a lengthy half-life, are examined to provide information on the relative mobilities of the elements involved. The proportions of U-235, U-238, and Pu-239 are found to be 88, 8, and 4 percent, respectively. It is shown that almost half of the fissioning U-235 nuclides were produced from the alpha-decay of Pu-239. The integrated neutron flux in the zone was calculated to be about 3.6 X 10 to the 20th n/cu cm.

  11. Radiation damage in nuclear fuel materials: The "rim'' effect in UO2 and damage in inert matrices for transmutation of actinides

    Science.gov (United States)

    Matzke, Hj.

    1996-08-01

    Polygonization or grain subdivision at high damage levels (often referred to as "rim effect") is gaining increasing importance for UO 2 which is the fuel of nuclear electricity producing power stations. Also, recently, the concept of replacing U-238, and hence replacing natural UO 2, by "inert matrices" for fissile U-235 or Pu-239, or also for transmutation of higher actinides (Np, Am, Cm) is being studied. High energy ion implantation was used to simulate fission damage in both UO 2 and in such matrices (e.g. Al 2O 3, MgAl 2O 4 etc.). The energy of implanted ions was varied between 40 keV and 2.6 GeV. Emphasis is given to the search for possible dose rate effects. Results on damage formation in UO 2 exist now for dose rate variations by more than a factor of 10 10. The implications for the technological application of inert matrix materials are briefly discussed.

  12. Time-Spectral Analysis Methods for Spent Fuel Assay Using Lead Slowing-Down Spectroscopy

    Science.gov (United States)

    Smith, L. Eric; Anderson, Kevin K.; Ressler, Jennifer J.; Shaver, Mark W.

    2010-08-01

    Nondestructive techniques for measuring the mass of fissile isotopes in spent nuclear fuel is a considerable challenge in the safeguarding of nuclear fuel cycles. A nondestructive assay technology that could provide direct measurement of fissile mass, particularly for the plutonium (Pu) isotopes, and improve upon the uncertainty of today's confirmatory methods is needed. Lead slowing-down spectroscopy (LSDS) has been studied for the spent fuel application previously, but the nonlinear effects of assembly self shielding (of the interrogating neutron population) have led to discouraging assay accuracy for realistic pressurized water reactor fuels. In this paper, we describe the development of time-spectral analysis algorithms for LSDS intended to overcome these self-shielding effects. The algorithm incorporates the tabulated energy-dependent cross sections from key fissile and absorbing isotopes, but leaves their mass as free variables. Multi-parameter regression analysis is then used to directly calculate not only the mass of fissile isotopes in the fuel assembly (e.g., Pu-239, U-235, and Pu-241), but also the mass of key absorbing isotopes such as Pu-240 and U-238. Modeling-based assay results using this self-shielding relationship indicate that LSDS has the potential to directly measure fissile isotopes with less than 5% average relative error for pressurized water reactor assemblies with burnup as high as 60 GWd/MTU. Shortcomings in the initial self-shielding model and potential improvements to the formulation are described.

  13. FY16 Safeguards Technology Cart-Portable Mass Spectrometer Project Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Cyril V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Whitten, William B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-02-01

    The Oak Ridge National Laboratory project for the Next Generation Safeguards Initiative Safeguards Technology Development Subprogram has been involved in the development of a cart portable mass spectrometer based on a Thermo ITQ ion trap mass spectrometer (referred to simply as the ITQ) for the field analysis of 235U/238U ratios in UF6. A recent discovery of the project was that combining CO2 with UF6 and introducing the mixture to the mass spectrometer (MS) appeared to increase the ionization efficiency and, thus, reduce the amount of UF6 needed for an analysis while also reducing the corrosive effects of the sample. However, initial experimentation indicated that mixing parameters should be closely controlled to ensure reproducible results. To this end, a sample manifold (SM) that would ensure the precise mixing of UF6 and CO2 was designed and constructed. A number of experiments were outlined and conducted to determine optimum MS and SM conditions which would provide the most stable isotope ratio analysis. The principal objective of the project was to provide a retrofit ITQ mass spectrometer operating with a SM capable of achieving a variation in precision of less than 1% over 1 hour of sampling. This goal was achieved by project end with a variation in precision of 0.5 to 0.8% over 1 hour of sampling.

  14. Propagation of neutron-reaction uncertainties through multi-physics models of novel LWR's

    Science.gov (United States)

    Hernandez-Solis, Augusto; Sjöstrand, Henrik; Helgesson, Petter

    2017-09-01

    The novel design of the renewable boiling water reactor (RBWR) allows a breeding ratio greater than unity and thus, it aims at providing for a self-sustained fuel cycle. The neutron reactions that compose the different microscopic cross-sections and angular distributions are uncertain, so when they are employed in the determination of the spatial distribution of the neutron flux in a nuclear reactor, a methodology should be employed to account for these associated uncertainties. In this work, the Total Monte Carlo (TMC) method is used to propagate the different neutron-reactions (as well as angular distributions) covariances that are part of the TENDL-2014 nuclear data (ND) library. The main objective is to propagate them through coupled neutronic and thermal-hydraulic models in order to assess the uncertainty of important safety parameters related to multi-physics, such as peak cladding temperature along the axial direction of an RBWR fuel assembly. The objective of this study is to quantify the impact that ND covariances of important nuclides such as U-235, U-238, Pu-239 and the thermal scattering of hydrogen in H2O have in the deterministic safety analysis of novel nuclear reactors designs.

  15. Study on the Impact of Thermal Agitation on Doppler Coefficient in Epithermal Range for Gd-Bearing Fuel

    Directory of Open Access Journals (Sweden)

    Satoshi Takeda

    2016-01-01

    Full Text Available The impact of thermal agitation on Doppler coefficient for Gd-bearing fuel was analyzed. It was found through the analysis that the impact increases when a small amount of Gd2O3 is added to pure UO2 fuel although the impact decreases for a large amount of Gd2O3. This tendency was discussed with the usage of simplified expression for the difference of Doppler coefficient. The simplified expression was used to consider the tendency, and it was revealed that the tendency mainly comes from the rapid decrement of multiplication factor and the relatively slow decrement of the magnitude of sensitivity coefficient of U-238 capture cross section at low Gd2O3 concentration. Similar tendency which shows a maximum impact on Doppler coefficient at interior concentration is expected for other UO2 fuel with a slight content of strong absorber. This indicates that Doppler coefficient of UO2 fuel system with low content of strong absorber should be analyzed carefully by considering thermal agitation in epithermal range.

  16. Radiological impact of natural radioactivity in Egyptian phosphate rocks, phosphogypsum and phosphate fertilizers.

    Science.gov (United States)

    El-Bahi, S M; Sroor, A; Mohamed, Gehan Y; El-Gendy, N S

    2017-05-01

    In this study, the activity concentrations of the natural radionuclides in phosphate rocks and its products were measured using a high- purity germanium detector (HPGe). The obtained activity results show remarkable wide variation in the radioactive contents for the different phosphate samples. The average activity concentration of (235)U, (238)U, (226)Ra, (232)Th and (40)K was found as (45, 1031, 786, 85 and 765Bq/kg) for phosphate rocks, (28, 1234, 457, 123 and 819Bq/kg) for phosphate fertilizers, (47, 663, 550, 79 and 870Bq/kg) for phosphogypsum and (25, 543, 409, 54 and 897Bq/kg) for single super phosphate respectively. Based on the measured activities, the radiological parameters (activity concentration index, absorbed gamma dose rate in outdoor and indoor and the corresponding annual effective dose rates and total excess lifetime cancer risk) were estimated to assess the radiological hazards. The total excess lifetime cancer risk (ELCR) has been calculated and found to be high in all samples, which related to high radioactivity, representing radiological risk for the health of the population. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Results of the Excreta Bioassay Quality Control Program for April 1, 2009 through March 31, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Cheryl L.

    2012-07-19

    A total of 58 urine samples and 10 fecal samples were submitted during the report period (April 1, 2009 through March 31, 2010) to General Engineering Laboratories, South Carolina by the Hanford Internal Dosimetry Program (IDP) to check the accuracy, precision, and detection levels of their analyses. Urine analyses for Sr, 238Pu, 239Pu, 241Am, 243Am 235U, 238U, elemental uranium and fecal analyses for 241Am, 238Pu and 239Pu were tested this year as well as four tissue samples for 238Pu, 239Pu, 241Am and 241Pu. The number of QC urine samples submitted during the report period represented 1.3% of the total samples submitted. In addition to the samples provided by IDP, GEL was also required to conduct their own QC program, and submit the results of analyses to IDP. About 33% of the analyses processed by GEL during the third year of this contract were quality control samples. GEL tested the performance of 21 radioisotopes, all of which met or exceeded the specifications in the Statement of Work within statistical uncertainty (Table 4).

  18. Lichens as biomonitors of uranium and other trace elements in an area of Kosovo heavily shelled with depleted uranium rounds

    Science.gov (United States)

    Di Lella, Luigi A.; Frati, Luisa; Loppi, Stefano; Protano, Giuseppe; Riccobono, Francesco

    This paper reports the results of a study using lichens as biomonitors to investigate the small-scale environmental distribution of uranium and other trace elements in an area of Kosovo (Djakovica) heavily shelled with depleted uranium (DU) anti-tank ammunition. The results of total uranium concentrations showed great variability and species-specific differences, mainly due to differences in the exposed surface area of the lichens. The uranium concentrations in lichen samples were rather similar at a site heavily shelled with DU ammunition and at a control site. Unexpectedly, the highest uranium concentrations were found at the control site. The observed U distribution can be explained by contamination of lichen thalli by soil particles. The soil geochemistry was similar at the two sampling sites. The 235U/ 238U ratios in the soil samples suggested a modest DU contribution only at the heavily shelled site. Measurements of U isotopes in lichens did not reveal DU pollution at the control site. The U isotopic ratios in lichens at the shelled site showed variable figures; only two samples were clearly contaminated by DU. There were no signs of contamination by other trace elements.

  19. Uranium isotopes in groundwater occurring at Amazonas State, Brazil.

    Science.gov (United States)

    da Silva, Márcio Luiz; Bonotto, Daniel Marcos

    2015-03-01

    This paper reports the behavior of the dissolved U-isotopes (238)U and (234)U in groundwater providing from 15 cities in Amazonas State, Brazil. The isotope dilution technique accompanied by alpha spectrometry were utilized for acquiring the U content and (234)U/(238)U activity ratio (AR) data, 0.01-1.4µgL(-1) and 1.0-3.5, respectively. These results suggest that the water is circulating in a reducing environment and leaching strata containing minerals with low uranium concentration. A tendency to increasing ARs values following the groundwater flow direction is identified in Manaus city. The AR also increases according to the SW-NE directions: Uarini→Tefé; Manacapuru→Manaus; Presidente Figueiredo→São Sebastião do Uatumã; and Boa Vista do Ramos→Parintins. Such trends are possibly related to several factors, among them the increasing acid character of the waters. The waters analyzed are used for human consumption and the highest dissolved U content is much lower than the maximum established by the World Health Organization. Therefore, in view of this radiological parameter they can be used for drinking purposes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Empirical calibration of uranium releases in the terrestrial environment of nuclear fuel cycle facilities.

    Science.gov (United States)

    Pourcelot, Laurent; Masson, Olivier; Saey, Lionel; Conil, Sébastien; Boulet, Béatrice; Cariou, Nicolas

    2017-05-01

    In the present paper the activity of uranium isotopes measured in plants and aerosols taken downwind of the releases of three nuclear fuel settlements was compared between them and with the activity measured at remote sites. An enhancement of 238U activity as well as 235U/238U anomalies and 236U are noticeable in wheat, grass, tree leaves and aerosols taken at the edge of nuclear fuel settlements, which show the influence of uranium chronic releases. Further plants taken at the edge of the studied sites and a few published data acquired in the same experimental conditions show that the 238U activity in plants is influenced by the intensity of the U atmospheric releases. Assuming that 238U in plant is proportional to the intensity of the releases, we proposed empirical relationships which allow to characterize the chronic releases on the ground. Other sources of U contamination in plants such as accidental releases and "delayed source" of uranium in soil are also discussed in the light of uranium isotopes signatures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. In situ U-series dating by laser-ablation multi-collector ICPMS: new prospects for Quaternary geochronology

    Science.gov (United States)

    Eggins, Stephen M.; Grün, Rainer; McCulloch, Malcolm T.; Pike, Alistair W. G.; Chappell, John; Kinsley, Les; Mortimer, Graham; Shelley, Michael; Murray-Wallace, Colin V.; Spötl, Christoph; Taylor, Lois

    2005-12-01

    The capabilities and potential applications of in situ dating of Quaternary materials using laser ablation-MC-ICPMS are explored. 234U/ 238U and 230Th/ 234U can be measured with precision sufficient for dating at a spatial resolution of 100 μm or better in samples that contain as a little as 1 ppm uranium. Moreover, U and Th concentrations and U-series isotope ratios can be continuously profiled to determine changes in age that occur with sample growth (e.g. in speleothems). These capabilities additionally permit the dating of bones, teeth and possibly molluscs, which are subject to post-mortem open-system behaviour of U-series isotopes, and can be employed to elucidate processes of U-series migration during weathering and diagenesis. A drawback of laser ablation-MC-ICPMS is that it cannot in general provide U-series age estimates with the high precision and accuracy of conventional TIMS or solution MC-ICPMS methods. However, sample preparation is straightforward, the amount of sample consumed negligible, and it can be used to rapidly characterise or screen and select samples from which more precise and accurate dates can be obtained using conventional methods. Given further instrumental developments and the establishment of suitable matrix-matched standards for carbonates and other materials, we foresee that laser ablation-MC-ICPMS will play an increasingly important role in Quaternary dating research.

  2. EBIS/T charge breeding for intense rare isotope beams at MSU

    CERN Document Server

    Schwarz, S; Marrs, R E; Kittimanapun, K; Lapierre, A; Mendez, A J; Ames, F; Beene, J R; Lindroos, M; Ahle, L E; Stracener, D W; Kester, O; Wenander, F; Lopez-Urrutia, J R Crespo; Dilling, J; Bollen, G

    2010-01-01

    Experiments with reaccelerated beams are an essential component of the science program of existing and future rare isotope beam facilities. NSCL is currently constructing ReA3, a reaccelerator for rare isotopes that have been produced by projectile fragmentation and in-flight fission and that have been thermalized in a gas stopper. The resulting low-energy beam will be brought to an Electron Beam Ion Source/Trap (EBIS/T) in order to obtain highly charged ions at an energy of 12 keV/u. This charge breeder is followed by a compact linear accelerator with a maximum beam energy of 3MeV/u for U-238 and higher energies for lighter isotopes. Next-generation rare isotope beam facilities like the Facility for Rare Isotope Beams FRIB, but also existing Isotope Separator On-line (ISOL) facilities are expected to provide rare-isotope beam rates in the order of 10(11) particles per second for reacceleration. At present the most promising scheme to efficiently start the reacceleration of these intense beams is the use of a...

  3. Comparison of thick-target (alpha,n yield calculation codes

    Directory of Open Access Journals (Sweden)

    Fernandes Ana C.

    2017-01-01

    Full Text Available Neutron production yields and energy distributions from (α,n reactions in light elements were calculated using three different codes (SOURCES, NEDIS and USD and compared with the existing experimental data in the 3.5-10 MeV alpha energy range. SOURCES and NEDIS display an agreement between calculated and measured yields in the decay series of 235U, 238U and 232Th within ±10% for most materials. The discrepancy increases with alpha energy but still an agreement of ±20% applies to all materials with reliable elemental production yields (the few exceptions are identified. The calculated neutron energy distributions describe the experimental data, with NEDIS retrieving very well the detailed features. USD generally underestimates the measured yields, in particular for compounds with heavy elements and/or at high alpha energies. The energy distributions exhibit sharp peaks that do not match the observations. These findings may be caused by a poor accounting of the alpha particle energy loss by the code. A big variability was found among the calculated neutron production yields for alphas from Sm decay; the lack of yield measurements for low (~2 MeV alphas does not allow to conclude on the codes’ accuracy in this energy region.

  4. Comparison of thick-target (alpha,n) yield calculation codes

    Science.gov (United States)

    Fernandes, Ana C.; Kling, Andreas; Vlaskin, Gennadiy N.

    2017-09-01

    Neutron production yields and energy distributions from (α,n) reactions in light elements were calculated using three different codes (SOURCES, NEDIS and USD) and compared with the existing experimental data in the 3.5-10 MeV alpha energy range. SOURCES and NEDIS display an agreement between calculated and measured yields in the decay series of 235U, 238U and 232Th within ±10% for most materials. The discrepancy increases with alpha energy but still an agreement of ±20% applies to all materials with reliable elemental production yields (the few exceptions are identified). The calculated neutron energy distributions describe the experimental data, with NEDIS retrieving very well the detailed features. USD generally underestimates the measured yields, in particular for compounds with heavy elements and/or at high alpha energies. The energy distributions exhibit sharp peaks that do not match the observations. These findings may be caused by a poor accounting of the alpha particle energy loss by the code. A big variability was found among the calculated neutron production yields for alphas from Sm decay; the lack of yield measurements for low ( 2 MeV) alphas does not allow to conclude on the codes' accuracy in this energy region.

  5. A Simple Formula for Local Burnup and Isotope Distributions Based on Approximately Constant Relative Reaction Rate

    Directory of Open Access Journals (Sweden)

    Cenxi Yuan

    2016-01-01

    Full Text Available A simple and analytical formula is suggested to solve the problems of the local burnup and the isotope distributions. The present method considers two extreme conditions of neutrons penetrating the fuel rod. Based on these considerations, the formula is obtained to calculate the reaction rates of 235U, 238U, and 239Pu and straightforward the local burnup and the isotope distributions. Starting from an initial burnup level, the parameters of the formula are fitted to the reaction rates given by a Monte Carlo (MC calculation. Then the present formula independently gives very similar results to the MC calculation from the starting to high burnup level but takes just a few minutes. The relative reaction rates are found to be almost independent of the radius (except (n,γ of  238U and the burnup, providing a solid background for the present formula. A more realistic examination is also performed when the fuel rods locate in an assembly. A combination of the present formula and the MC calculation is expected to have a nice balance between the numerical accuracy and time consumption.

  6. Results Assessment of Intercomparison Exercise CSN/CIEMAT-2012 among Spanish National Laboratories of Environmental Radioactivity (Soil); Evaluación de la Intercomparación CSN/CIEMAT-2012 entre los Laboratorios Nacionales de Radiactividad Ambiental (Suelo)

    Energy Technology Data Exchange (ETDEWEB)

    Trinidad, J. A.; Gascó, C.; Llauradó, M.

    2015-07-01

    This report describes the results assessment of the intercomparsion exercise among environmental radioactivity laboratories, organised by Spanish Regulatory Institution (CSN) and prepared and evaluated by UB and CIEMAT respectively. The exercise has been carried out following the international standards ISO-43 and ISO/IUPAC that provide a useful guide to perform proficiency tests and inter-laboratories comparisons. The selected matrix for this year (2012) was soil, that was enriched with artificial radionuclides (137Cs, 60Co, 55Fe, 63Ni, 90Sr, 241Am, 239+240Pu and 238Pu) and contained natural radionuclides (234U, 238U, U-natural 230Th, 226Ra, 210Pb, 228Ra, 228Ac, 234Th, 214Bi, 214Pb, 212Pb, 208Tl and 40K) at environmental level of activity concentration. Two soil matrixes were prepared in order to separate 55Fe and 63Ni analysis. The z-score test was applied to determine how much the laboratories differ from the reference value. The reference value for this exercise was the median of the results from the different laboratories and their standard deviations to achieve a more complete and objective study of the laboratories performance. The participant laboratories have demonstrated a satisfactory quality level for measuring the natural and artificial radionuclides content in this matrix. The study has showed a homogeneous behaviour of the laboratories.

  7. Uranium: A Dentist's perspective.

    Science.gov (United States)

    Toor, R S S; Brar, G S

    2012-01-01

    Uranium is a naturally occurring radionuclide found in granite and other mineral deposits. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). On an average, 1% - 2% of ingested uranium is absorbed in the gastrointestinal tract in adults. The absorbed uranium rapidly enters the bloodstream and forms a diffusible ionic uranyl hydrogen carbonate complex (UO2HCO3+) which is in equilibrium with a nondiffusible uranyl albumin complex. In the skeleton, the uranyl ion replaces calcium in the hydroxyapatite complex of the bone crystal. Although in North India, there is a risk of radiological toxicity from orally ingested natural uranium, the principal health effects are chemical toxicity. The skeleton and kidney are the primary sites of uranium accumulation. Acute high dose of uranyl nitrate delays tooth eruption, and mandibular growth and development, probably due to its effect on target cells. Based on all previous research and recommendations, the role of a dentist is to educate the masses about the adverse effects of uranium on the overall as well as the dental health. The authors recommended that apart from the discontinuation of the addition of uranium to porcelain, the Public community water supplies must also comply with the Environmental Protection Agency (EPA) standards of uranium levels being not more than 30 ppb (parts per billion).

  8. Investigation of Space and Energy Distributions of Neutrons Generated in Lead Target and Uranium Blanket of the Electronuclear System "Energy plus Transmutation" under Irradiation with Protons at 1.5 GeV

    CERN Document Server

    Zhuk, I V; Krivopustov, M I; Sosnin, A N; Chultem, D; Vestmaer, V; Tumendelger, T; Zaveryukha, O S; Pavlyuk, A B

    2002-01-01

    The work contains the results of space-energy distributions of neutrons in U/Pb assembly, consisting of extended lead target and the model of natural uranium blanket irradiated with relativistic protons at 1.5 GeV. The research is carried out in the framework of a series of experiments using the model of subcritical heterogeneous electronuclear system at the Laboratory of High Energies, JINR, Dubna ("Investigation of Physical Aspects of Electronuclear Method of Energy Production and Transmutation of Radioactive Waste Using Beams from JINR Synchrophasotron/Nuclotron" - project "Energy plus Transmutation"). The results of measurements and calculations of ^{235}U, ^{238}U and ^{232}Th fission rate distributions as well as threshold spectral indexes {\\bar\\sigma_f^{^{232}Th}}/{\\bar\\sigma_f^{^{235}U}} and {\\bar\\sigma_f^{^{238}U}}/{\\bar\\sigma_f^{^{235}U}} along the radius of the target and model uranium blanket are presented. The results of measurements and calculations of ^{234}U, ^{236}U and ^{237}Np fission rate ...

  9. Uranium comparison by means of AMS and ICP-MS and Pu and 137Cs results around an Italian Nuclear Power Plant

    Science.gov (United States)

    De Cesare, M.; Tims, S. G.; Fifield, L. K.

    2015-04-01

    Italy built and commissioned 4 nuclear power plants between 1958-1978, which delivered a total of 1500 MW. All four were closed down after the Chernobyl accident following a referendum in 1987. One of the plants was Garigliano, commissioned in 1959. This plant used a 160 MW BWR1 (SEU of 2.3 %) and was operational from 1964 to 1979, when it was switched off for maintenance. It was definitively stopped in 1982, and is presently being decommissioned. We report here details on the chemistry procedure and on the measurements for soil samples, collected up to 4.5 km from the Nuclear Plant. A comparison between uranium (238U) concentration as determined by means of AMS (Accelerator Mass Spectrometry) and by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) techniques respectively at the ANU (Australian National University) and at the Ecowise company in Canberra, Australia, is reported, as well as 236U and 239;240Pu concentration results detected by AMS. 236U/238U and 240Pu/239Pu isotopic ratios by means of AMS are also provided. A contamination from Chernobyl is visible in the 137Cs/239+240Pu activity ratio measurements.

  10. Modification of Fe-B based metallic glasses using swift heavy ions

    Directory of Open Access Journals (Sweden)

    Kirby N.

    2012-10-01

    Full Text Available We report on small-angle x-ray scattering (SAXS measurements of amorphous Fe80B20, Fe85B15, Fe81B13.5Si3.5C2, and Fe40Ni40B20 metallic alloys irradiated with 11.1 MeV/u 132Xe, 152Sm, 197Au, and 8.2 MeV/u 238U ions. SAXS experiments are nondestructive and give evidence for ion track formation including quantitative information about the size of the track radius. The measurements also indicate a cylindrical track structure with a sharp transition to the undamaged surrounding matrix material. Results are compared with calculations using an inelastic thermal spike model to deduce the critical energy loss for the track formation threshold. The damage recovery of ion tracks produced in Fe80B20 by 11.1 MeV/u 197Au ions was studied by means of isochronal annealing yielding an activation energy of 0.4 ± 0.1 eV

  11. Calibration factor determination for solid nuclear track detectors CR-39 type exposed to Rn-222; Determinacao do fator de calibracao para detectores solidos de tracos nucleares tipo CR-39 expostos a Rn-222

    Energy Technology Data Exchange (ETDEWEB)

    Cazula, Camila Dias; Campos, Marcia Pires de; Mazzilli, Barbara Paci, E-mail: cdcazula@ipen.br, E-mail: mpcampos@ipen.br, E-mail: mazzilli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    In the detection method with solid nuclear track detector, when a heavy particle rests on the detector surface, causes a breakdown in their molecular structure forming a trace. One of the typical applications of these detectors is the measurement of the concentration of Rn -222 in air, a noble radioactive gas, part of the U-238 series, emitting alpha particles and important in epidemiological studies to protect individuals from natural radiation. To determine the concentration of Rn -222 in the air in a room is necessary to know the density of lines (traces / cm{sup 2}) on the detector surface, the exposure time and the calibration factor. The determination of the calibration factor for CR-39 detectors was taken from the exposure of these to a known concentration of Rn-222. Therefore, the detectors were placed inside a cell of Lucas adapted and subsequently exposed to a concentration of Rn-222 15 kBq / m{sup 3}, by means of the apparatus RN-150 Pylon Electronics Incorporation, which has a source of Ra-226 and releases known concentrations of Rn-222. Six calibration factor determinations were performed, the average value obtained was 0.0534 ±0.0021 (traces / cm{sup 2} per Bq / m{sup 3} day). The results are consistent with literature values for the same type of detector and showed good reproducibility.

  12. Controlling Pu behavior on Titania: Implications for LEU Fission-Based Mo-99 Production

    Energy Technology Data Exchange (ETDEWEB)

    Youker, Amanda J. [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States; Brown, M. Alex [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States; Heltemes, Thad A. [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States; Vandegrift, George F. [Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States

    2017-09-29

    Molybdenum-99 is the parent isotope of the most widely used isotope, technetium-99m, in all diagnostic nuclear medicine procedures. Due to proliferation concerns associated with the use of highly enriched uranium (HEU), the preferred method of fission-based Mo-99 production uses low enriched uranium (LEU) targets. Using LEU versus HEU for Mo-99 production produces similar to 30 times more Pu-239, due to neutron capture on U-238 to produce Np-239, which ultimately decays to Pu-239 (t(1/2) = 24,110 yr). Argonne National Laboratory is supporting a potential US Mo-99 producer in their efforts to produce Mo-99 from an LEU solution. In order to mitigate the generation of large volumes of greater-than-class-C (GTCC) low level waste (Pu-239 concentrations greater than 1 nCi/g), we have focused our efforts on the separation chemistry of Pu and Mo with a titania sorbent in sulfate media. Results from batch and column experiments show that temperature and acid wash concentration can be used to control Pu behavior on titania.

  13. Development of a standard data base for FBR core nuclear design. 10. Reevaluation of atomic number density of JOYO Mk-II core

    Energy Technology Data Exchange (ETDEWEB)

    Numata, Kazuyuki; Sato, Wakaei [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Ishikawa, Makoto; Arii, Yoshio [Nuclear Energy System Incorporation, Tokyo (Japan)

    1999-07-01

    The material composition of JOYO Mk-II core components in its initial core was reevaluated as a part of the effort for developing a standard data base for FBR core nuclear design. The special feature of the reevaluation is to treat the decay of Pu-241 isotope, so that the atomic number densities of Pu-241 and Am-241 in fuel assemblies can be exactly evaluated on the initial critical date, Nov. 22nd, 1982. Further, the atomic number densities of other core components were also evaluated to improve the analytical accuracy. Those include the control rods which were not so strictly evaluated in the past, and the dummy fuels and the neutron sources which were not treated in the analytical model so far. The results of the present reevaluation were as follows: (1) The changes of atomic number densities of the major nuclides such as Pu-239, U-235 and U-238 were about {+-}0.2 to 0.3%. On the other hand, the number density of Pu-241, which was the motivation of the present work, was reduced by 12%. From the fact, the number densities in the past analysis might be based on the isotope measurement of the manufacturing point of time without considering the decay of Pu-241. (2) As the other core components, the number densities of control rods and outer reflector-type A were largely improved. (author)

  14. Propagation of neutron-reaction uncertainties through multi-physics models of novel LWR's

    Directory of Open Access Journals (Sweden)

    Hernandez-Solis Augusto

    2017-01-01

    Full Text Available The novel design of the renewable boiling water reactor (RBWR allows a breeding ratio greater than unity and thus, it aims at providing for a self-sustained fuel cycle. The neutron reactions that compose the different microscopic cross-sections and angular distributions are uncertain, so when they are employed in the determination of the spatial distribution of the neutron flux in a nuclear reactor, a methodology should be employed to account for these associated uncertainties. In this work, the Total Monte Carlo (TMC method is used to propagate the different neutron-reactions (as well as angular distributions covariances that are part of the TENDL-2014 nuclear data (ND library. The main objective is to propagate them through coupled neutronic and thermal-hydraulic models in order to assess the uncertainty of important safety parameters related to multi-physics, such as peak cladding temperature along the axial direction of an RBWR fuel assembly. The objective of this study is to quantify the impact that ND covariances of important nuclides such as U-235, U-238, Pu-239 and the thermal scattering of hydrogen in H2O have in the deterministic safety analysis of novel nuclear reactors designs.

  15. The Graphite Isotope Ratio Method (GIRM): A Plutonium Production Verification Tool

    Energy Technology Data Exchange (ETDEWEB)

    JP McNeece; BD Reid; TW Wood

    1999-01-01

    Over the lifetime of a production reactor, neutrons from the fission process not only convert U-238 into plutonium but also bring about changes in the elements of the reactor's core components. Components such as shielding, pressure vessels, coolant piping, control rods, structural supports, and, in the case of graphite moderated reactors, the solid graphite moderator are all affected. Because a reactor's total plutonium production is directly related to total neutron fluence, and, likewise, changes in the elements and isotopes of a reactor's core components are directly related to fluence; it was argued that measuring these changes could provide an accurate estimate of a reactor's total plutonium production. The U.S. Department of Energy funds a project at Pacific Northwest National Laboratory (PNNL) to develop this concept into a practical plutonium production verification tool for graphite moderated reactors. The following sections describe the GIRM project development process. The purpose of this document is to provide a simple, concise description of the graphite isotope ratio method (GIRM) for use as a verification tool in estimating a graphite-moderated reactor's total plutonium production. The description covers the theory behind the technique and how the method is actually applied.

  16. Uranium comparison by means of AMS and ICP-MS and Pu and 137Cs results around an Italian Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    De Cesare M.

    2015-01-01

    Full Text Available Italy built and commissioned 4 nuclear power plants between 1958-1978, which delivered a total of 1500 MW. All four were closed down after the Chernobyl accident following a referendum in 1987. One of the plants was Garigliano, commissioned in 1959. This plant used a 160 MW BWR1 (SEU of 2.3 % and was operational from 1964 to 1979, when it was switched off for maintenance. It was definitively stopped in 1982, and is presently being decommissioned. We report here details on the chemistry procedure and on the measurements for soil samples, collected up to 4.5 km from the Nuclear Plant. A comparison between uranium (238U concentration as determined by means of AMS (Accelerator Mass Spectrometry and by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry techniques respectively at the ANU (Australian National University and at the Ecowise company in Canberra, Australia, is reported, as well as 236U and 239;240Pu concentration results detected by AMS. 236U/238U and 240Pu/239Pu isotopic ratios by means of AMS are also provided. A contamination from Chernobyl is visible in the 137Cs/239+240Pu activity ratio measurements.

  17. The Efficiency of the BC-720 Scintillator in a High-Energy (20--800 MeV) Accelerator Neutron Field

    Energy Technology Data Exchange (ETDEWEB)

    Miles, Leslie H. [Univ. of Missouri, Columbia, MO (United States)

    2005-12-01

    High-energy neutron doses (>20 MeV) are of little importance to most radiation workers. However, space and flight crews, and people working around medical and scientific accelerators receive over half of their radiation dose from high-energy neutrons. Unfortunately, neutrons are difficult to measure, and no suitable dosimetry has yet been developed to measure this radiation. In this paper, basic high-energy neutron interactions, characteristics of high-energy neutron environments, present neutron dosimetry, and quantities used in neutron dosimetry are discussed before looking into the potential of the BC-720 scintillator to improve dosimetry. This research utilized 800 MeV protons impinging upon the WNR Facility spallation neutron source at Los Alamos National Laboratory. Time-of-flight methods and a U-238 Fission Chamber were used to aid evaluation of the efficiency of the BC-720. Results showed that the efficiency is finite over the 20–650 MeV energy region studied, although it decreases by a factor of ten between 40 and 100 MeV. This limits the use of this dosimeter to measure doses at sitespecific locations. It also encourages modifications to use this dosimeter for any unknown neutron field. As such, this dosimeter has the potential for a small, lightweight, real-time dose measurement, which could impact neutron dosimetry in all high-energy neutron environments.

  18. Results of the Interlaboratory Exercise CSN/CIEMAT-02 Among Environmental Radioactivity Laboratories (Sea Fish); Resultados del Ejercicio Interlaboratorios de Radiactividad Ambiental CSN/CIEMAT-02 (Fauna Marina)

    Energy Technology Data Exchange (ETDEWEB)

    Romero gonzalez, M. L.

    2003-07-01

    The document describes the outcome of the CSN/CIEMAT-02 interlaboratory test comparison among environmental radioactivity laboratories. The exercise was organised according to the ISO-43 and the ISO/IUPAC/AOAC Harmonized Protocol for the proficiency testing of analytical laboratories. The test sample was a reference materials provided by the IAEA-MEL (IAE Marine Environmental Laboratory, Monaco), a sea fish containing environmental levels of U-238, U-234, K-40, Pb-210, Ra-226, Sr-90, Cs-137, Co-60, Pu-(239+240), Am-241 and Tc-99. The results of the exercise were computed for 32 participating laboratories, and their analytical performance was assessed using the z-score approach. A raised percentage of satisfactory laboratory performance has been obtained for all the analysis, being the best performance in gamma measurements. The laboratories have made an effort to calculate the combined uncertainty of the radiochemical determinations. Most of the laboratories have demonstrated its competence in performing the study analysis and also the adequate measuring capability of their detection equipment even in conditions close to detection limits. The study has shown the capacity of participant laboratories to perform radioactive determinations in environmental sea fish samples with satisfactory quality levels. (Author) 6 refs.

  19. Results from the Argonne, Los Alamos, JAERI collaboration

    Energy Technology Data Exchange (ETDEWEB)

    Meadows, J.; Smith, D.; Greenwood, L. [Argonne National Lab., IL (United States); Haight, R. [Los Alamos National Lab., NM (United States); Ikeda, Y.; Konno, C. [Japan Atomic Energy Research Inst., Ibaraki (Japan)

    1993-07-01

    Four sample packets containing elemental Ti, Fe, Ni, Cu, Nb, Ag, Eu, Tb and Hf have been irradiated in three distinct accelerator neutron fields, at Argonne National Laboratory and Los Alamos National Laboratory, USA, and Japan Atomic Energy Research Institute, Tokai, Japan. The acquired experimental data include differential cross sections and integral cross sections for the continuum neutron spectrum produced by 7-MeV deuterons incident on thick Be-metal target. The U-238(n,f) cross section was also measured at 10.3 MeV as a consistency check on the experimental technique. This the third progress report on a project which has been carried out under the auspices of an IAEA Coordinated Research Program entitled ``Activation Cross Sections for the Generation Of Long-lived Radionuclides of Importance in Fusion Reactor Technology``. The present report provides the latest results from this work. Comparison is made between the 14.7-MeV cross-section values obtained from the separate investigations at Argonne and JAERI. Generally, good agreement observed within the experimental errors when consistent sample parameters, radioactivity decay data and reference cross values are employed. A comparison is also made between the experimental results and those derived from calculations using a nuclear model. Experimental neutron information on the Be(d,n) neutron spectrum was incorporated in the comparisons for the integral results. The agreement is satisfactory considering the various uncertainties that are involved.

  20. Uranium and radium activities measurements and calculation of effective doses in some drinking water samples in Morocco

    Directory of Open Access Journals (Sweden)

    Oum Keltoum Hakam

    2015-09-01

    Full Text Available Purpose: As a way of prevention, we have measured the activities of uranium and radium isotopes (234U, 238U, 226Ra, 228Ra for 30 drinking water samples collected from 11 wells, 9 springs (6 hot and 3 cold, 3 commercialised mineral water, and 7 tap water samples. Methods: Activities of the Ra isotopes were measured by ultra-gamma spectrometry using a low background and high efficiency well type germanium detector. The U isotopes were counted in an alpha spectrometer.Results: The measured Uranium and radium activities are similar to those published for other non-polluting regions of the world. Except in one commercialised gaseous water sample, and in two hot spring water samples, the calculated effective doses during one year are inferior to the reference level of 0.1 mSv/year recommended by the International Commission on Radiological Protection. Conclusion: These activities don't present any risk for public health in Morocco. The sparkling water of Oulmes is occasionally consumed as table water and waters of warm springs are not used as main sources of drinking water.  

  1. Results of The Excreta Bioassay Quality Control Program For April 1, 2008 through March 31, 2009

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Cheryl L.

    2010-06-01

    A total of 62 urine samples and 6 spiked fecal samples were submitted during the report period (April 1, 2008 through March 31, 2009) to General Engineering Laboratories, South Carolina by the Hanford Internal Dosimetry Program (IDP) to check the accuracy, precision, and detection levels of their analyses. Urine analyses for Sr, 238Pu, 239Pu, 241Am, 243Am 235U, 238U, elemental uranium and fecal analyses for 241Am, 238Pu and 239Pu were tested this year. The number of QC urine samples submitted during the report period represented 1.3% of the total samples submitted. In addition to the samples provided by IDP, GEL was also required to conduct their own QC program, and submit the results of analyses to IDP. About 34% of the analyses processed by GEL during the third year of this contract were quality control samples. GEL tested the performance of 21 radioisotopes, all of which met or exceeded the specifications in the Statement of Work within statistical uncertainty. IDP concluded that GEL was performing well for all analyses tested, and concerns identified earlier were satisfactorily resolved (see section on Follow-up on Concerns During the Fourth Contract Year).

  2. Radium and radon in water supplies from the Texas Gulf coastal aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Cech, I.; Lemma, M.; Prichard, H.M.; Kreitler, C.W.

    1988-01-01

    A sampling of the domestic water for two isotopes of the uranium (U)-238 series, radium (Ra)-226 and radon (Rn)-222, was conducted in parts of the Texas Gulf Coast to understand the distribution patterns of these radioisotopes in residential and commercial water supplies. Samples were obtained from consumers' taps, as well as at well heads to evaluate variation due to location and depth of water sources. Computer mapping and statistical analyses were used to depict patterns of Ra and Rn distribution. The concentrations varied depending on water source. No measurable Ra or Rn were found in surface water supplies, whereas up to 23 pCi l/sup -1/ of Ra and 3300 pCi l/sup -1/ of Rn were observed in some of the wells in northwest and southwest Harris County. The Rn concentrations were observed to increase with depth, but for Ra peak concentrations were found between 180 and 320 m below the surface. High concentrations of Ra and Rn were associated with wells developed on the flanks of piercement-type salt domes, along faults, and near streams

  3. Results Assessment of Intercomparison Exercise CSN/CIEMAT-2011 among Spanish National Laboratories of Environmental Radioactivity (Water); Evaluación de la Intercomparación CSN/CIEMAT-2011 entre los Laboratorios Nacionales de Radiactividad Ambiental (Agua)

    Energy Technology Data Exchange (ETDEWEB)

    Gascó, C.; Trinidad, J. A.; Llauradó, M.

    2015-07-01

    This report describes the results assessment of the intercomparsion exercise among environmental radioactivity laboratories, organised by Spanish Regulatory Institution (CSN) and prepared and evaluated by UAB and CIEMAT respectively. The exercise has been carried out following the international standards ISO-43 and ISO/IUPAC that provide a useful guide to perform proficiency tests and inter-laboratories comparisons. The selected matrix for this year (2011) was deionized water, simulating drinking water, that was enriched with artificial radionuclides (Cs-137, Co-60, Fe-55, Ni-63, Sr-90, Am-241 and Pu-238) and contained natural radionuclides (U-234, U-238, U-natural, Pb-210, Po-210, Th-230, Ra-226 and K-40) at environmental level of activity concentration. A second matrix of deionized water was prepared with I-129 and C-14. The z-score test was applied to determine how much the laboratories differ from the reference value. The reference value for this exercise was the median of the results from the different laboratories and their standard deviations to achieve a more complete and objective study of the laboratories performance. The participant laboratories have demonstrated a satisfactory quality level for measuring the natural and artificial radionuclides content in this matrix. The study has showed a homogeneous behaviour of the laboratories.

  4. Evaluation of the use of reverse osmosis to eliminate natural radionuclides from water samples.

    Science.gov (United States)

    Nieto, Antonio; Palomo, Marta; Ruana, Josep; Peñalver, Alejandra; Aguilar, Carme; Borrull, Francesc

    2013-12-01

    The objective of drinking water treatment plants (DWTP) is to supply the population with tap water that is in optimal condition and in compliance with water quality regulations. In the DWTP of L'Ampolla (Tarragona, Spain), slightly high values of gross alpha activity and the amount of salts in the raw water have been observed. Conventional treatment has reduced these levels only minimally. This study tested a tertiary treatment based on reverse osmosis is tested in an industrial pilot plant (240 m3/day) The efficiency of this pilot plant to reduce the gross alpha and beta activities and the activity of some individual radioisotopes (U(238), U(234), U(235) and Ra(226)) was tested. Results showed that the elimination of alpha emitters was greater than 90%, whereas the elimination of beta emitters was about 35%. Overall, the data provided evidence that the pilot plant is effective for removing different radionuclides that can be present in the incoming water treated. Therefore, tertiary treatment based on reverse osmosis has a positive effect in water quality.

  5. IXth millenium B.C. ceramics from Niger: detection of a U-series disequilibrium and TL dating

    Science.gov (United States)

    Guibert, P.; Schvoerer, M.; Etcheverry, M. P.; Szepertyski, B.; Ney, C.

    A set of pottery sherds collected from two ancient neolithic sites in Niger (Tagalagal and Adrar Bous 10) has been dated by thermoluminescence. The natural radioactivity of these ceramics and of their surrounding sediments was measured using low background gamma spectrometry and atomic emission plasma spectrometry. With gamma spectrometry, the comparison between the activity of 238U (deduced from the 235U and 234Th gamma emissions) and that of 226Ra (deduced from 214Pb and 214Bi γ emissions in equilibrium with 222Rn) shows a significant disequilibrium of the U-series. The activity ratio {38U}/{226Ra}, which is greater than unity in this case, is interpreted as a result of either uranium enrichment ( 234U, 235U, 238U) or radium impoverishment that has been occurring since the burying of the archaeological artefacts. The effects of the changes in radiochemical composition on the annual dose are discussed and various determinations of the annual dose are analysed according to different hypotheses of disequilibrium (either permanent state or recent occurrence). The TL results: Tagalagal — 9820±780-10, 180±780 years/1993, Adrar Bous 10 — 9530±750-10,500±730 years/1993, are consistent with the radiocarbon dates obtained from charcoals collected at the same locations (the uncalibrated 14C dates belong to the 9100-9370 BP range). These results are of fundamental interest for the chronology of early neolithic cultures.

  6. Characteristic differences of LEU and HEU cores at the German FRJ-2 research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nabbi, R.; Wolters, J.; Damm, G. [Central Research Reactor Division, Forschungszentrum Juelich, 52425 Juelich (Germany)

    2002-07-01

    As a sophisticated computational method for reactor physics analysis and fuel management an MCNP model in very high fidelity was developed and coupled with a depletion code and applied to the HEU-LEU core conversion study. The analysis show that as a consequence of the high amount of U-238, the amount of U-235 in the LEU core is about 14% higher than in the HEU core. The reduction of the thermal flux varies between 16% (core) and 5% in the reflector zone. The rate of U-235 burnup in the LEU core is approx. 11.5% lower which allows an extension of irradiation time. Due to the effect of neutron spectrum the worth of the absorber system decreases in an LEU core by 17% resulting in a decrease of shutdown and excess reactivity. The kinetic parameters of the core are slightly reduced causing changes in the reactivity values and transient behavior of the core. The moderator coefficient is decreased by 18% and the Doppler coefficient is increased by 63%. Due to shortening of the absorption length of the fission neutrons the prompt neutron lifetime is reduced by 7%. (author)

  7. Magnetic identification of climatic signals in turbiditic sediments of the Galician Bank, NW Iberian Margin

    Science.gov (United States)

    Mohamed-Falcon, K. J.; Rey, D.; Rubio, B.

    2010-12-01

    The Galician Bank, on the NW Iberian margin, receives a limited supply of local continental sediments due to the existence of the Galician Interior basin, which traps most of the local detrital sediments discharged in the area, potentially allowing the preservation of signals of global or regional significance. High resolution magnetic analyses of a suite of gravity cores recovered from the flanks of the Galician bank indicate that these sediments are composed of three main sources; local turbiditic sequences, which comprise most of the sedimentary record, hemipelagic sediments dominated by biogenic carbonates, and ice-rafted debris with magnetic characteristics compatible with Heinrich events. Combination of the magnetic properties with geochemical data confirms the preservation of a climatic signal carried by detrital sediments in the hemipelagic facies. The transport time of these sediments, as determined by the departure from secular equilibrium of the 234U/238U ratio caused by α-recoil ejection 234U confirms a remote origin for the detrital particles in these hemipelagites, whereas shorter transport time in the turbidites is consistent with a local origin. These results confirm the utility of magnetic properties, in combination with geochemical analyses as a rapid and sensitive tool to identify climatic signals in turbiditic sediments.

  8. Using of the natural radioactive elements for determining Ge-detector efficiencies

    CERN Document Server

    Tertyshnik, E G

    2012-01-01

    A method is proposed to use of the mixture of Uran oxide and non-active matrix (e.g., NaCl) and also potassium and lanthanum for determining Ge-detector efficiencies. The preparations containing of known amouts of the U or K, or La were measured by means of the Ge-detector, which a efficiency curve has been obtained through the reference solutions of 241Am, 109Cd, 57Co, 139Ce, 137Cs, 60Co. Results the measurements were compared the activities of the preparations calculated from mass of 235U, 238U, 138La, 40K in the samples, its natural abundance, half lives and intensities of gamma lines. Discrepancy of the activities in the energy range between 163 and 1461 keV does not exeed 7 %. For correct comparison of the activities the coefficients {\\omega} were calculated, which took into consideration a varied sorption of gamma-rays in water and in mixture of the Uran oxide and matrix.

  9. Analysis of the VENUS out-of-core activation measurements using MCBEND

    Energy Technology Data Exchange (ETDEWEB)

    Blaise, P.D.; Wouters, R.M. de [Tractebel Energy Engineering, Brussels (Belgium); Abderrahim, H.A. [SCK-CEN, Mol (Belgium). Fuel Research Div.

    1994-12-31

    The VENUS-1 critical assembly simulates a UO2-loaded core and the internal structures from the core baffle to the neutron pad, in a generic 3-loop plant. VENUS-2 contained mixed oxide PuO2--UO2 fuel pins in the eight outer rows. Several out-of-core threshold activation rates (In-115, Np-237, Zn-64, Al-27, Ni-58, U-238, Rh-103) have been measured at numerous locations in water zones and steel structures. From these measurements, equivalent fission fluxes have been established by dividing the activation rates by cross-sections weighted by the U-235 fission spectrum. Calculations of equivalent fission fluxes have been carried out with the Monte Carlo transport program (MCBEND). The average ratio calculation/experiment (C/E) in the core barrel, with 80 dosimeters and 7 types of reactions, is 1.02 {+-} 0.03 ({sigma}). Further away from the core, the average C/E in the neutron pad from 13 measurements is 1.01 {+-} 0.08 ({sigma}).

  10. Uncertainty in the delayed neutron fraction in fuel assembly depletion calculations

    Directory of Open Access Journals (Sweden)

    Aures Alexander

    2017-01-01

    Full Text Available This study presents uncertainty and sensitivity analyses of the delayed neutron fraction of light water reactor and sodium-cooled fast reactor fuel assemblies. For these analyses, the sampling-based XSUSA methodology is used to propagate cross section uncertainties in neutron transport and depletion calculations. Cross section data is varied according to the SCALE 6.1 covariance library. Since this library includes nu-bar uncertainties only for the total values, it has been supplemented by delayed nu-bar uncertainties from the covariance data of the JENDL-4.0 nuclear data library. The neutron transport and depletion calculations are performed with the TRITON/NEWT sequence of the SCALE 6.1 package. The evolution of the delayed neutron fraction uncertainty over burn-up is analysed without and with the consideration of delayed nu-bar uncertainties. Moreover, the main contributors to the result uncertainty are determined. In all cases, the delayed nu-bar uncertainties increase the delayed neutron fraction uncertainty. Depending on the fuel composition, the delayed nu-bar values of uranium and plutonium in fact give the main contributions to the delayed neutron fraction uncertainty for the LWR fuel assemblies. For the SFR case, the uncertainty of the scattering cross section of U-238 is the main contributor.

  11. Unique challenges for storage and disposal of DOE-owned SNF at the INEEL

    Energy Technology Data Exchange (ETDEWEB)

    Mathews, T.A.

    1998-03-01

    Non-commercial Spent Nuclear Fuel (SNF) owned by the Department of Energy presents some unique challenges for interim storage as well as ultimate disposal in a repository. There is an important link between Yucca Mountain Repository work and the future needs of the DOE SNF program. Close coordination and early definition of acceptance criteria are essential. Much of the Yucca Mountain Repository work has focused on commercial SNF which has very high structural integrity and a well documented set of characteristics and burn-up histories. In contrast, DOE non-commercial SNF at the Idaho National Environmental and Engineering Laboratory (INEEL) represents over two hundred fifty fuel types, much of which is degraded. Fuel designs by DOE were centered around various test objectives in experimental reactors. The result was a proliferation of fuel types. Interest in enhanced heat transfer led to use of sodium as a bond between the fuel and cladding. The desire for smaller more compact reactors with higher power densities led to a variety of enrichments from less than 20% to greater than 90%. INEEL has most of the US U-233 spent nuclear fuel, which came from breeder reactor concepts and consideration of a thorium fuel cycle. These various fuel types now must be placed in safe, stable interim dry storage. Emphasis is being placed on the use of commercially available dry storage designs and independent spent fuel storage installations licensed under NRC criteria. A lot of technological development is being done to characterize fuels that do not have the documented fabrication and operational histories of commercial LWR fuels. Program objectives are safe interim storage and least cost transition to geological repository storage.

  12. New perspectives for undoped CaF2 scintillator as a threshold activation neutron detector

    Directory of Open Access Journals (Sweden)

    Sibczynski Pawel

    2018-01-01

    Full Text Available In this paper we present the prompt photofission neutron detection performance of undoped CaF2 scintillator using Threshold Activation Detection (TAD. The study is carried out in the frame of C-BORD Horizon 2020 project, during which an efficient toolbox for high volume freight non-intrusive inspection (NII is under development. Technologies for radiation monitoring are the part of the project. Particularly, detection of various radiological threats on country borders plays an important significant role in Homeland Security applications. Detection of illegal transfer of Special Nuclear Material (SNM - 235U, 233U and 239Pu - is particular due to the potential use for production of nuclear weapon as well as radiological dispersal device (RDD V known also as a “dirty bomb”. This technique relies on activation of 19F nuclei in the scintillator medium by fast neutrons and registration of high-energy β particles and γ-rays from the decay of reaction products. The radiation from SNM is detected after irradiation in order to avoid detector blinding. Despite the low 19F(n,α16N or 19F(n,p19O reaction cross-section, the method could be a good solution for detection of shielded nuclear material. Results obtained with the CaF2 detector were compared with the previous study done for BaF2 and 3He detector. These experimental results were obtained using 252Cf source and 9 MeV Varian Linatron M9 linear accelerator (LINAC. Finally, performance of the prompt neutron detection system based on CaF2 will be validated at Rotterdam Seaport during field trails in 2018.

  13. Mini-MITEE: Ultra Small, Ultra Light NTP Engines for Robotic Science and Manned Exploration Missions

    Science.gov (United States)

    Powell, James; Maise, George; Paniagua, John

    2006-01-01

    A compact, ultra lightweight Nuclear Thermal Propulsion (NTP) engine design is described with the capability to carry out a wide range of unique and important robotic science missions that are not possible using chemical or Nuclear Electric Propulsion (NEP). The MITEE (MInature ReacTor EnginE) reactor uses hydrogeneous moderator, such as solid lithium-7 hydride, and high temperature cermet tungsten/UO2 nuclear fuel. The reactor is configured as a modular pressure tube assembly, with each pressure tube containing an outer annual shell of moderator with an inner annular region of W/UO2 cermet fuel sheets. H2 propellant flows radially inwards through the moderator and fuel regions, exiting at ~3000 K into a central channel that leads to a nozzle at the end of the pressure tube. Power density in the fuel region is 10 to 20 megawatts per liter, depending on design, producing a thrust output on the order of 15,000 Newtons and an Isp of ~1000 seconds. 3D Monte Carlo neutronic analyses are described for MITEE reactors utilizing various fissile fuel options (U-235, U-233, and Am242m) and moderators (7LiH and BeH2). Reactor mass ranges from a maximum of 100 kg for the 7LiH/U-235 option to a minimum of 28 kg for the BeH2/Am-242 m option. Pure thrust only and bi-modal (thrust plus electric power generation) MITEE designs are described. Potential unique robotic science missions enabled by the MITEE engine are described, including landing on Europa and exploring the ice sheet interior with return of samples to Earth, hopping to and exploring multiple sites on Mars, unlimited ramjet flight in the atmospheres of Jupiter, Saturn, Uranus, and Neptune and landing on, and sample return from Pluto.

  14. The Thorium-Cycle: safe, abundant power for the new millennium

    Science.gov (United States)

    Don, May; George, Kim; Peter, Mcintyre; Charles, Meitzler; Robert, Rogers; Akhdior, Sattarov; Mustafa, Yavuz

    2001-10-01

    A design has been developed for using accelerator-driven thorium fission to produce electric power. A thorium-cycle reactor works by electro-breeding. A pattern of thorium fuel rods is supported in a vessel containing molten lead. A beam of high-energy (1 GeV) protons is targeted in the center of the vessel, and produces a copious flux of energetic neutrons by spallation. The neutrons transmute the thorium nuclei two steps up the periodic table to U233, which fissions rapidly to produce thermal energy. The lead serves as the spallation target, the moderator, and the heat exchange medium to transfer heat from the core to steam exchangers above the core. The thorium cycle has several important advantages over current uranium-cycle fission technology: it is intrinsically stable it cannot melt down; it eats its own waste; it cannot produce bomb-grade isotopes; and there are sufficient thorium reserves to supply the entire Earth’s energy economy for the next millennium. The concept of a thorium-cycle power reactor was first proposed by Rubbia in 1995. Key problems in the original concept were the proton injector (15 MW beam power), reliability of accelerator systems, and parasitic absorption of neutrons by fission products during the life of the core. We have addressed all three problems in a design for a flux-coupled stack of isochronous cyclotrons, delivering a pattern of 7 independent beams to the core. An interdisciplinary collaboration is being formed to develop the concept to a serious design.

  15. Nuclear Safeguards Considerations For The Pebble Bed Modular Reactor (PBMR)

    Energy Technology Data Exchange (ETDEWEB)

    Phillip Casey Durst; David Beddingfield; Brian Boyer; Robert Bean; Michael Collins; Michael Ehinger; David Hanks; David L. Moses; Lee Refalo

    2009-10-01

    High temperature reactors (HTRs) have been considered since the 1940s, and have been constructed and demonstrated in the United Kingdom (Dragon), United States (Peach Bottom and Fort Saint Vrain), Japan (HTTR), Germany (AVR and THTR-300), and have been the subject of conceptual studies in Russia (VGM). The attraction to these reactors is that they can use a variety of reactor fuels, including abundant thorium, which upon reprocessing of the spent fuel can produce fissile U-233. Hence, they could extend the stocks of available uranium, provided the fuel is reprocessed. Another attractive attribute is that HTRs typically operate at a much higher temperature than conventional light water reactors (LWRs), because of the use of pyrolytic carbon and silicon carbide coated (TRISO) fuel particles embedded in ceramic graphite. Rather than simply discharge most of the unused heat from the working fluid in the power plant to the environment, engineers have been designing reactors for 40 years to recover this heat and make it available for district heating or chemical conversion plants. Demonstrating high-temperature nuclear energy conversion was the purpose behind Fort Saint Vrain in the United States, THTR-300 in Germany, HTTR in Japan, and HTR-10 and HTR-PM, being built in China. This resulted in nuclear reactors at least 30% or more thermodynamically efficient than conventional LWRs, especially if the waste heat can be effectively utilized in chemical processing plants. A modern variant of high temperature reactors is the Pebble Bed Modular Reactor (PBMR). Originally developed in the United States and Germany, it is now being redesigned and marketed by the Republic of South Africa and China. The team examined historical high temperature and high temperature gas reactors (HTR and HTGR) and reviewed safeguards considerations for this reactor. The following is a preliminary report on this topic prepared under the ASA-100 Advanced Safeguards Project in support of the NNSA Next

  16. New perspectives for undoped CaF2 scintillator as a threshold activation neutron detector

    Science.gov (United States)

    Sibczynski, Pawel; Dziedzic, Andrzej; Grodzicki, Krystian; Iwanowska-Hanke, Joanna; Moszyński, Marek; Swiderski, Lukasz; Syntfeld-Każuch, Agnieszka; Wolski, Dariusz; Carrel, Frédérick; Grabowski, Amélie; Hamel, Matthieu; Laine, Frederic; Sari, Adrien; Iovene, Alessandro; Tintori, Carlo; Fontana, Cristiano; Pino, Felix

    2018-01-01

    In this paper we present the prompt photofission neutron detection performance of undoped CaF2 scintillator using Threshold Activation Detection (TAD). The study is carried out in the frame of C-BORD Horizon 2020 project, during which an efficient toolbox for high volume freight non-intrusive inspection (NII) is under development. Technologies for radiation monitoring are the part of the project. Particularly, detection of various radiological threats on country borders plays an important significant role in Homeland Security applications. Detection of illegal transfer of Special Nuclear Material (SNM) - 235U, 233U and 239Pu - is particular due to the potential use for production of nuclear weapon as well as radiological dispersal device (RDD) V known also as a "dirty bomb". This technique relies on activation of 19F nuclei in the scintillator medium by fast neutrons and registration of high-energy β particles and γ-rays from the decay of reaction products. The radiation from SNM is detected after irradiation in order to avoid detector blinding. Despite the low 19F(n,α)16N or 19F(n,p)19O reaction cross-section, the method could be a good solution for detection of shielded nuclear material. Results obtained with the CaF2 detector were compared with the previous study done for BaF2 and 3He detector. These experimental results were obtained using 252Cf source and 9 MeV Varian Linatron M9 linear accelerator (LINAC). Finally, performance of the prompt neutron detection system based on CaF2 will be validated at Rotterdam Seaport during field trails in 2018.

  17. India's baseline plan for nuclear energy self-sufficiency.

    Energy Technology Data Exchange (ETDEWEB)

    Bucher, R .G.; Nuclear Engineering Division

    2009-01-01

    outlined in a seminal paper by Drs. H. J. Bhabha and N. B. Prasad presented at the Second United Nations Conference on the Peaceful Uses of Atomic Energy in 1958. The paper described a three stage plan for a sustainable nuclear energy program consistent with India's limited uranium but abundant thorium natural resources. In the first stage, natural uranium would be used to fuel graphite or heavy water moderated reactors. Plutonium extracted from the spent fuel of these thermal reactors would drive fast reactors in the second stage that would contain thorium blankets for breeding uranium-233 (U-233). In the final stage, this U-233 would fuel thorium burning reactors that would breed and fission U-233 in situ. This three stage blueprint still reigns as the core of India's civil nuclear power program. India's progress in the development of nuclear power, however, has been impacted by its isolation from the international nuclear community for its development of nuclear weapons and consequent refusal to sign the Nuclear Nonproliferation Treaty (NPT). Initially, India was engaged in numerous cooperative research programs with foreign countries; for example, under the 'Atoms for Peace' program, India acquired the Cirus reactor, a 40 MWt research reactor from Canada moderated with heavy water from the United States. India was also actively engaged in negotiations for the NPT. But, on May 18, 1974, India conducted a 'peaceful nuclear explosion' at Pokharan using plutonium produced by the Cirus reactor, abruptly ending the era of international collaboration. India then refused to sign the NPT, which it viewed as discriminatory since it would be required to join as a non-nuclear weapons state. As a result of India's actions, the Nuclear Suppliers Group (NSG) was created in 1975 to establish guidelines 'to apply to nuclear transfers for peaceful purposes to help ensure that such transfers would not be diverted to unsafeguarded nuclear fuel

  18. ANALISIS PERUBAHAN MASSA BAHAN FISIL DAN NON FISIL DALAM TERAS PWR 1000 MWe DENGAN ORIGEN-ARP 5.1

    Directory of Open Access Journals (Sweden)

    Anis Rohanda

    2015-03-01

    Full Text Available Teras reaktor merupakan tempat terjadinya reaksi pembelahan (fisi yang terkendali. Komponen reaktor seperti bahan bakar, kelongsong (cladding dan air pendingin memiliki peranan penting dalam keberlangsungan reaksi fisi. Reaksi fisi mengakibatkan terbentuknya sejumlah nuklida hasil fisi dan hasil aktivasi. Hasil fisi berasal dari reaksi tangkapan neutron termal dengan bahan fisil sedangkan hasil aktivasi berasal dari interaksi bahan non fisil seperti material kelongsong dan pendingin oleh neutron dan gamma. Pada setiap pengoperasian suatu reaktor, informasi perubahan massa bahan fisil dan non fisil sangat berguna untuk manajemen bahan bakar dalam teras, seperti pengaturan reaktivitas, optimasi dan pemuatan bahan bakar. Untuk itu perlu dilakukan penelitian mengenai perubahan bahan fisil dan non fisil tersebut dalam teras reaktor. Hal ini dapat dilakukan dengan mengamati perubahan massa dari material dalam teras reaktor. Penelitian ini memiliki tujuan untuk mengetahui perubahan massa unsur penyusun material dalam teras, seperti massa dari unsur penyusun elemen bahan bakar nuklir, kelongsong dan air pendingin setelah digunakan dalam teras. Dari perubahan massa tersebut dapat diketahui fraksi bakar atau tingkat konsumsi bahan bakar yang digunakan. Penelitian dilakukan pada basis reaktor PLTN tipe PWR buatan pabrikan asal Amerika Serikat berdaya 1000 MWe dengan menggunakan code penghitung inventori hasil fisi ORIGEN-ARP 5.1, yaitu versi terbaru dari ORIGEN dengan library khusus reaktor daya. Hasil analisis menunjukkan bahwa bahan fisil U-235 mengalami pengurangan massa hingga 58% atau lebih dari separuhnya dari massa U-235 awal untuk tiap kali siklus operasi. Bahan fertil U-238 hanya mengalami pengurangan massa sekitar 2% dari massa awalnya tiap kali siklus operasi. Lain halnya dengan bahan non fisil yang mengalami perubahan massa yang berbeda-beda untuk tiap kali siklus operasinya yang tergantung pada tampang lintang aktivasi serta laju peluruhan dan

  19. Current Status of the Transmutation Reactor Technology and Preliminary Evaluation of Transmutation Performance of the KALIMER Core

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Ser Gi; Sim, Yoon Sub; Kim, Yeong Il; Kim, Young Gyum; Lee, Byung Woon; Song, Hoon; Lee, Ki Bog; Jang, Jin Wook; Lee, Dong Uk

    2005-08-15

    Recently the most countries using the nuclear power plants for electricity generation have been faced with the problem of the preparation of the repository for the disposition of the nuclear waste generated from LWR. It was well-known that the issues related with long term risk of the radioactive wastes for the future generations are due only to 1% of the total waste. This small fraction of 1% consists of transuranic (TRU) nuclides such as Pu, Np, Am, Cm and the long lived fission products such as Tc and I. For the transuranic (TRU) nuclides, their half lives range from several years to several hundred thousands years and hence their radioactive toxicity can be lasted over very long time period. This has made the change of the rule of the fast spectrum reactor from the economical use of uranium resource through breeding to the reduction of the nuclear waste through the transmutation. The purpose of this study is to obtain the basic knowledge on the nuclear transmutation technology and to suggest the technical solution ways for the future technology development and enhancement through a survey of the state-of-art of the international research on the nuclear transmutation. The increase of the transmutation rate requires the reduction of the breeding ratio. In fact, the transmutation rate is determined by the breeding ratio. The reduction of the breeding ratio can be achieved by reducing the U-238 content in fuel or increasing the neutron leakage through core boundary or absorbing the neutrons by using some absorbers. However, the reduction of the U-238 content results in the degradation of the fuel Doppler coefficient that is one of the most important safety-related parameters and the reduction of the effective delayed neutron fraction that is related with the controllability of the reactor core. Also, the increase of the transmutation rate can lead to the increase of the coolant void reactivity worth unless some ways to reduce the coolant void reactivity are not

  20. Effects of glacial/post-glacial weathering compared with hydrothermal alteration - implications for matrix diffusion. Results from drillcore studies in porphyritic quartz monzodiorite from Aespoe SE Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Landstroem, Ove [Studsvik Eco and Safety AB, Nykoeping (Sweden); Tullborg, Eva-Lena [Terralogica AB, Graabo (Sweden); Eriksson, Gunda; Sandell, Yvonne [Studsvik Nuclear AB, Nykoeping (Sweden)

    2001-08-01

    The effects of hydrothermal + subsequent low temperature alteration and glacial/post-glacial weathering have been studied in two cores of quartz monzodiorite. One core (YA 1192) was drilled into the hydrothermally altered wall rock of a water-conducting fracture exposed at 170 m depth in the access tunnel to the Aespoe Hard Rock Laboratory. The other one (Bas 1) was drilled from an outcrop with a glacially polished surface, 1 km north of the YA 1192 site. Both drill cores were sectioned into mm-thick slices perpendicular to the core axis. The fracture filling of the YA 1192 core, the weathered surface of the BAS 1 core and the different slices were analysed for major and trace elements and isotopes of U and Th. The altered zone of the YA 1192 core extends to approx. 2.5 cm from the fracture surface. The alteration (mainly plagioclase {yields} albite + sericite + epidote) has resulted in a higher porosity and formation of sorbing secondary minerals (e.g. sericite), favouring matrix diffusion. Increased Br concentrations in the altered zone are indicative of saline water in pores and micro fractures i.e. the presence of a diffusion medium. 234U/238U activity ratios > 1 and increased Cs in the altered zone are then interpreted as diffusion of U and Cs from fracture groundwater and subsequent sorption. The U migration is geologically recent (< 1 Ma). The 2.5 cm altered zone (corresponding to the zone of active matrix diffusion) significantly exceeds the visible red staining zone (0.5 cm) caused by hematite/FeOOH micrograins, emphasizing the need of microscopy to identify zones of alteration. The conspicuous weathering at the BAS 1 site is confined to a narrow rim of the bedrock surface (approx. 0.2-0.5 cm thick). Mass balance calculations for this rim (based on immobility of K) indicate that mechanical erosion has dominated over chemical dissolution processes (is roughly 10 times greater). The chemical weathering has affected mainly plagioclase and chlorite resulting

  1. 2005 Closure Assessments for WMA-C Tank Farms: Numerical Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Freedman, Vicky L; Zhang, Z F; Waichler, Scott R; Wurstner, Signe K

    2005-09-20

    In support of CH2M HILL Hanford Group, Inc.'s (CHG) closure of the Hanford Site Single-Shell Tank (SST) Waste Management Area (WMA) tank farms, numerical simulations of flow and solute transport were executed to investigate different potential contaminant source scenarios that may pose long-term risks to groundwater from the closure of the C Tank Farm. These simulations were based on the initial assessment effort (Zhang et al., 2003), but implemented a revised approach that examined a range of key parameters and multiple base cases. Four different potential source types were identified to represent the four base cases, and included past leaks, diffusion releases from residual wastes, leaks during retrieval, and ancillary equipment sources. Using a two-dimensional cross section through the C Tank Farm (Tanks C-103–C-112) and a unit release from Tank C-112, two solutes (uranium-238 (U-238) and technetium-99 (Tc 99)) were transported through the problem domain. To evaluate the effect of sorption on contaminant transport, seven different sorption coefficients were simulated for U 238. Apart from differences in source releases, all four base cases utilized the same median parameter values to describe flow and contaminant transport at the WMA C. Forty-six additional cases were also run that examined individual transport responses to the upper and lower limits of the median parameter values implemented in the base case systems. For the conservative solute, Tc-99, results amongst the base cases showed that the simulations investigating past leaks demonstrated the highest peak concentrations and the earliest arrival times (48 years) due to the proximity of the plume to the water table and the high recharge rate before surface barriers were installed. Simulations investigating leaks during retrieval predicted peak concentrations ~60 times smaller than the past leak cases, and corresponding arrival times that occurred ~70 years later. The diffusion release base case

  2. Bioconcentration of artificial radionuclides in edible mushrooms: in situ and in vitro studies

    Energy Technology Data Exchange (ETDEWEB)

    Dementyev, Dmitry V.; Manukovsky, Nikolai S.; Bolsunovsky, Alexander Ya.; Alexandrova, Yuliyana V. [Institute of Biophysics, Siberian Branch of the Russian Academy of Sciences, 660036, Krasnoyarsk (Russian Federation)

    2014-07-01

    Some areas of the Yenisei River basin are affected by the operation of the Mining-and-Chemical Combine (MCC), producing weapons-grade plutonium. Flood plain soils of the Yenisei contain a wide range of artificial radionuclides, including transuranium elements, which can be accumulated by living organisms. Concentrations of artificial radionuclides and heavy metals accumulated by mushrooms may be several orders of magnitude higher than those accumulated by plants, and, thus, mushrooms may be used as bio-concentrators of radionuclides and heavy metals for bioremediation of contaminated areas. The purposes of this study were to investigate 1) species specificity of accumulation of artificial radionuclides by edible mushrooms in radioactively contaminated areas of the Yenisei River flood plain and 2) accumulation rates of artificial radionuclides, including transuranium elements, in mushrooms under laboratory conditions. Species specificity of accumulation of artificial radionuclides and uranium by mushrooms was analyzed for 12 species of edible mushrooms. The study was performed at the sites affected by MCC operation, which were divided into two groups: 1) the sites only affected by aerosol-bound radionuclides and 2) the sites that also received waterborne radionuclides. Field studies showed great interspecific variations in Cs-137 accumulation by mushrooms. Activity concentrations of Cs-137 in bioindicator species Suillus granulatus and S. Luteus reached 10 kBq/kg dry weight. S. granulatus and S. luteus are concentrators of Cs-137, as suggested by the analysis of concentration factors (CFs), which reached 0.7-16 for these mushroom species. The CF of U-238 in fruiting bodies of the mushrooms was no greater than 0.11. Yenisei flood plain soils contain a wide range of transuranium elements, which can accumulate in environmental objects. Laboratory experiments on accumulation of Am-241 from solution by mycelium and Am-241 accumulation by fruiting bodies of mushrooms

  3. The discovery and character of Pleistocene calcrete uranium deposits in the Southern High Plains of west Texas, United States

    Science.gov (United States)

    Van Gosen, Bradley S.; Hall, Susan M.

    2017-12-18

    This report describes the discovery and geology of two near-surface uranium deposits within calcareous lacustrine strata of Pleistocene age in west Texas, United States. Calcrete uranium deposits have not been previously reported in the United States. The west Texas uranium deposits share characteristics with some calcrete uranium deposits in Western Australia—uranium-vanadium minerals hosted by nonpedogenic calcretes deposited in saline lacustrine environments.In the mid-1970s, Kerr-McGee Corporation conducted a regional uranium exploration program in the Southern High Plains province of the United States, which led to the discovery of two shallow uranium deposits (that were not publicly reported). With extensive drilling, Kerr-McGee delineated one deposit of about 2.1 million metric tons of ore with an average grade of 0.037 percent U3O8 and another deposit of about 0.93 million metric tons of ore averaging 0.047 percent U3O8.The west-Texas calcrete uranium-vanadium deposits occur in calcareous, fine-grained sediments interpreted to be deposited in saline lakes formed during dry interglacial periods of the Pleistocene. The lakes were associated with drainages upstream of a large Pleistocene lake. Age determinations of tephra in strata adjacent to one deposit indicate the host strata is middle Pleistocene in age.Examination of the uranium-vanadium mineralization by scanning-electron microscopy indicated at least two generations of uranium-vanadium deposition in the lacustrine strata identified as carnotite and a strontium-uranium-vanadium mineral. Preliminary uranium-series results indicate a two-component system in the host calcrete, with early lacustrine carbonate that was deposited (or recrystallized) about 190 kilo-annum, followed much later by carnotite-rich crusts and strontium-uranium-vanadium mineralization in the Holocene (about 5 kilo-annum). Differences in initial 234U/238U activity ratios indicate two separate, distinct fluid sources.

  4. Sediment transport time measured with U-Series isotopes: Resultsfrom ODP North Atlantic Drill Site 984

    Energy Technology Data Exchange (ETDEWEB)

    DePaolo, Donald J.; Maher, Kate; Christensen, John N.; McManus,Jerry

    2006-06-05

    High precision uranium isotope measurements of marineclastic sediments are used to measure the transport and storage time ofsediment from source to site of deposition. The approach is demonstratedon fine-grained, late Pleistocene deep-sea sediments from Ocean DrillingProgram Site 984A on the Bjorn Drift in the North Atlantic. The sedimentsare siliciclastic with up to 30 percent carbonate, and dated by sigma 18Oof benthic foraminifera. Nd and Sr isotopes indicate that provenance hasoscillated between a proximal source during the last three interglacialperiods volcanic rocks from Iceland and a distal continental sourceduring glacial periods. An unexpected finding is that the 234U/238Uratios of the silicate portion of the sediment, isolated by leaching withhydrochloric acid, are significantly less than the secular equilibriumvalue and show large and systematic variations that are correlated withglacial cycles and sediment provenance. The 234U depletions are inferredto be due to alpha-recoil loss of234Th, and are used to calculate"comminution ages" of the sediment -- the time elapsed between thegeneration of the small (<_ 50 mu-m) sediment grains in the sourceareas by comminution of bedrock, and the time of deposition on theseafloor. Transport times, the difference between comminution ages anddepositional ages, vary from less than 10 ky to about 300 to 400 ky forthe Site 984A sediments. Long transport times may reflect prior storagein soils, on continental shelves, or elsewhere on the seafloor. Transporttime may also be a measure of bottom current strength. During the mostrecent interglacial periods the detritus from distal continental sourcesis diluted with sediment from Iceland that is rapidly transported to thesite of deposition. The comminution age approach could be used to dateQuaternary non-marine sediments, soils, and atmospheric dust, and may beenhanced by concomitant measurement of 226Ra/230Th, 230Th/234U, andcosmogenic nuclides.

  5. Image segmentation for uranium isotopic analysis by SIMS: Combined adaptive thresholding and marker controlled watershed approach

    Energy Technology Data Exchange (ETDEWEB)

    Willingham, David G.; Naes, Benjamin E.; Heasler, Patrick G.; Zimmer, Mindy M.; Barrett, Christopher A.; Addleman, Raymond S.

    2016-05-31

    A novel approach to particle identification and particle isotope ratio determination has been developed for nuclear safeguard applications. This particle search approach combines an adaptive thresholding algorithm and marker-controlled watershed segmentation (MCWS) transform, which improves the secondary ion mass spectrometry (SIMS) isotopic analysis of uranium containing particle populations for nuclear safeguards applications. The Niblack assisted MCWS approach (a.k.a. SEEKER) developed for this work has improved the identification of isotopically unique uranium particles under conditions that have historically presented significant challenges for SIMS image data processing techniques. Particles obtained from five NIST uranium certified reference materials (CRM U129A, U015, U150, U500 and U850) were successfully identified in regions of SIMS image data 1) where a high variability in image intensity existed, 2) where particles were touching or were in close proximity to one another and/or 3) where the magnitude of ion signal for a given region was count limited. Analysis of the isotopic distributions of uranium containing particles identified by SEEKER showed four distinct, accurately identified 235U enrichment distributions, corresponding to the NIST certified 235U/238U isotope ratios for CRM U129A/U015 (not statistically differentiated), U150, U500 and U850. Additionally, comparison of the minor uranium isotope (234U, 235U and 236U) atom percent values verified that, even in the absence of high precision isotope ratio measurements, SEEKER could be used to segment isotopically unique uranium particles from SIMS image data. Although demonstrated specifically for SIMS analysis of uranium containing particles for nuclear safeguards, SEEKER has application in addressing a broad set of image processing challenges.

  6. Geochemistry and hydrology of perched groundwater springs: assessing elevated uranium concentrations at Pigeon Spring relative to nearby Pigeon Mine, Arizona (USA)

    Science.gov (United States)

    Beisner, Kimberly R.; Paretti, Nicholas; Tillman, Fred; Naftz, David L.; Bills, Donald; Walton-Day, Katie; Gallegos, Tanya J.

    2017-01-01

    The processes that affect water chemistry as the water flows from recharge areas through breccia-pipe uranium deposits in the Grand Canyon region of the southwestern United States are not well understood. Pigeon Spring had elevated uranium in 1982 (44 μg/L), compared to other perched springs (2.7–18 μg/L), prior to mining operations at the nearby Pigeon Mine. Perched groundwater springs in an area around the Pigeon Mine were sampled between 2009 and 2015 and compared with material from the Pigeon Mine to better understand the geochemistry and hydrology of the area. Two general groups of perched groundwater springs were identified from this study; one group is characterized by calcium sulfate type water, low uranium activity ratio 234U/238U (UAR) values, and a mixture of water with some component of modern water, and the other group by calcium-magnesium sulfate type water, higher UAR values, and radiocarbon ages indicating recharge on the order of several thousand years ago. Multivariate statistical principal components analysis of Pigeon Mine and spring samples indicate Cu, Pb, As, Mn, and Cd concentrations distinguished mining-related leachates from perched groundwater springs. The groundwater potentiometric surface indicates that perched groundwater at Pigeon Mine would likely flow toward the northwest away from Pigeon Spring. The geochemical analysis of the water, sediment and rock samples collected from the Snake Gulch area indicate that the elevated uranium at Pigeon Spring is likely related to a natural source of uranium upgradient from the spring and not likely related to the Pigeon Mine.

  7. Comparison of radon levels in building basements and above- ground floors

    Energy Technology Data Exchange (ETDEWEB)

    Cazula, C.; Campos, M.; Mazzilli, B. [IPEN/CNEN-SP, Sao Paulo (Brazil)

    2014-07-01

    Radon-222, a decay product of Ra-226, is a natural radioactive noble gas that can be found in soil, water and air. Radon and its short-lived decay products in the atmosphere are the most important contributors to human exposure from natural sources. Radon is recognized as the second most significant risk for lung cancer after tobacco smoking. The World Health Organization established a concentration of 100 Bq m{sup -3} for radon in air, in order to limit its hazards. The main source of radon exposition indoors comes from Ra-226, a decay product of the U-238 natural series, present in rocks and soils underneath the building and, to a lesser extent, in the building materials. The dynamics of radon production in rocks and soil and its subsequent indoors emanation is quite complex. It is controlled by factors such as soil permeability and water content, meteorological variability, building foundation characteristics and the usual positive differential pressure between the soil and the indoor environment. This is normally sufficient to bring soil gas from the ground into the building. Radon gas can enter a building by several mechanisms, but the most significant ones are diffusion and pressure-driven flow from the ground. Usually, cracks and holes in the floor and walls and gaps around service pipes are the main entrance for the radon gas. Studies indicated that indoor radon concentration present significant variation on the basement, ground floor and upper floors. The aim of this study is to determine the radon levels in building basements and above- ground floors in the city of Sao Paulo. Radon measurements were carried out through the passive method with solid-state nuclear- track detectors (CR-39), because of their simplicity and long-term integrated read-out. The exposure period was, at least, three months, covering one year minimum, in order to determine the seasonal variation of indoor radon concentration. Document available in abstract form only. (authors)

  8. Results of the Interlaboratory Exercise CNS/CIEMAT-05 among Environmental Radioactivity Laboratories (Vegetable Ash); Evaluacion de la Intercomparacion CSN/CIEMAT-2005 entre Laboratorios Nacionales Radiactividad Ambiental (Ceniza Vegetal)

    Energy Technology Data Exchange (ETDEWEB)

    Romero Gonzalez, M. L.; Barrera Izquierdo, M.; Valino Garcia, F.

    2006-07-01

    The document describes the outcome of the CSN/CIEMAT-05 interlaboratory test comparison among environmental radioactivity laboratories. The exercise was organised according to the ISO-43 and the IUPAC {sup I}nternational harmonised protocol for the proficiency testing of analytical chemistry laboratories{sup .} The exercise has been designed to evaluate the capability of national laboratories to determine environmental levels of radionuclides in vegetable ash samples. The sample has been prepared by the Environmental Radiation Laboratory, from the University of Barcelona, and it contains the following radionuclides: Sr-90, Pu-238, Am-241, Th-230, Pb-210, U-238, Ra-226, K-40, Ra-228, TI-208, Cs- 137 and Co-60. Reference values have been established TROUGH the kind collaboration of three international laboratories of recognized experience: IAEA MEL and IRSN-Orsay. The results of the exercise were computed for 35 participating laboratories and their analytical performance was assessed using the z-score approach. Robust statistics of the participant's results was applied to obtain the median and standard deviation, to achieve a more complete and objetiva study of the laboratories' performance. Some difficulties encountered to dissolve the test sample caused a lower response of analyses involving radiochemical separation, thus some laboratories couldn't apply their routine methods and no conclusions on PU-238, Am-241 and Th-230 performances have been obtained. The exercise has revealed an homogeneous behaviour of laboratories, being statistical parameters from the results close to the reference values. The study has shown that participant laboratories perform radioactive determinations in vegetable ash samples with satisfactory quality levels. (Author) 6 refs.

  9. Results Assessment of Intercomparison Exercise CSN/CIEMAT-2010 among Spanish National Laboratories of Environmental Radioactivity (Diet Ashes); Evaluacion de la Intercomparacion CSN/CIEMAT-2010 entre los Laboratorios Nacionales de Radiactividad Ambiental (Ceniza de Dieta)

    Energy Technology Data Exchange (ETDEWEB)

    Gasco, C.; Trinidad, J. A.; Llaurado, M.; Suarez, J. A.

    2012-06-08

    This report describes the results assessment of the intercomparison exercise among environmental radioactivity laboratories, organised by Spanish Regulatory Institution (CSN) and prepared and evaluated by UAB and CIEMAT respectively. The exercise has been carried out following the international standards ISO-43 and ISO/IUPAC that provide a useful guide to perform proficiency tests and inter-laboratories comparisons. The selected matrix for this year (2010) was a diet ash obtained from the ashing of a whole fresh diet (breakfast, lunch and dinner), that was enriched with artificial radionuclides (Cs-137, Co-60,Fe-55,Ni-63,Sr-90,Am-241,Pu-238,Pu-239,240 y C-14) and contained natural radionuclides (U-234, U-238, U-natural Th-230, Th-234, Ra-226, Ra-228, Pb-210, Pb-212, Pb-214, Bi-214, Ac-228, Tl-208, K-40) at environmental level of activity concentration. The z-score test was applied to determine how much the laboratories differ from the reference value. The reference value for this exercise was the median of the results from the different laboratories and their standard deviations to achieve a more complete and objective study of the laboratories performance. The participant laboratories have demonstrated a satisfactory quality level for measuring the natural and artificial radionuclides content in this matrix. The reference values obtained through the medians show a negative bias for Pb-210 and Th-234 when comparing to the given values of external qualified laboratories from ENEA and IRSN and positive one for K-40. (Author)

  10. Neutronic analysis stochastic distribution of fuel particles in Very High Temperature Gas-Cooled Reactors

    Science.gov (United States)

    Ji, Wei

    The Very High Temperature Gas-Cooled Reactor (VHTR) is a promising candidate for Generation IV designs due to its inherent safety, efficiency, and its proliferation-resistant and waste minimizing fuel cycle. A number of these advantages stem from its unique fuel design, consisting of a stochastic mixture of tiny (0.78mm diameter) microspheres with multiple coatings. However, the microsphere fuel regions represent point absorbers for resonance energy neutrons, resulting in the "double heterogeneity" for particle fuel. Special care must be taken to analyze this fuel in order to predict the spatial and spectral dependence of the neutron population in a steady-state reactor configuration. The challenges are considerable and resist brute force computation: there are over 1010 microspheres in a typical reactor configuration, with no hope of identifying individual microspheres in this stochastic mixture. Moreover, when individual microspheres "deplete" (e.g., burn the fissile isotope U-235 or transmute the fertile isotope U-238 (eventually) to Pu-239), the stochastic time-dependent nature of the depletion compounds the difficulty posed by the stochastic spatial mixture of the fuel, resulting in a prohibitive computational challenge. The goal of this research is to develop a methodology to analyze particle fuel randomly distributed in the reactor, accounting for the kernel absorptions as well as the stochastic depletion of the fuel mixture. This Ph.D. dissertation will address these challenges by developing a methodology for analyzing particle fuel that will be accurate enough to properly model stochastic particle fuel in both static and time-dependent configurations and yet be efficient enough to be used for routine analyses. This effort includes creation of a new physical model, development of a simulation algorithm, and application to real reactor configurations.

  11. Subsidence and volcanism of the Haleakala Ridge, Hawaii

    Science.gov (United States)

    Moore, J.G.; Clague, D.A.; Ludwig, K. R.; Mark, R.K.

    1990-01-01

    Side-looking sonar (GLORIA) mapping has revealed a series of four arcuate bands of high sonic backscatter on the crest of the Haleakala Ridge, a major rift-zone ridge extending 135 km east of the island of Maui. Dredge recovery indicates that the shallowest of these bands is a drowned coral reef, and the deeper bands are also inferred to be coral reefs. The reefs occur above a prominent submarine bench 1500-2500 m deep on the ridge (H-terrace) that marks the shoreline at the end of vigorous shield building of Haleakala volcano when lava flows ceased crossing and reworking the shoreline. Since their growth these reefs have subsided as much as 2200 m and have tilted systematically about 20 m/km southward as a result of post-reef volcanic loading on the island of Hawaii, whose center of mass is about directly south of the Haleakala Ridge. The 234U/238U age of the dredged coral is 750 ?? 13 ka, in reasonable agreement with an age of 850 ka for the underlying H terrace previously estimated from its relationship to other dated reefs to the southwest. Basalt glass fragments dredged from the Haleakala Ridge below the H terrace are tholeiitic and contain high sulfur indicative of eruption in water deeper than 200 m. Basalt glass fragments associated with the reefs above the H terrace are dominantly tholeiitic and contain intermediate sulfur contents, indicative of subaqueous eruption in shallow, near-shore conditions. One alkalic glass fragment was recovered above the H terrace. These relations indicate that the morphologic end of shield building as recorded by construction of the H terrace was not accompanyed by a change from tholeiitic to alkalic basalt; instead tholeiite eruptions continued for some time before the erupted lava became alkalic. ?? 1990.

  12. Phantom Archean crust in Mangaia hotspot lavas and the meaning of heterogeneous mantle

    Science.gov (United States)

    Herzberg, C.; Cabral, R. A.; Jackson, M. G.; Vidito, C.; Day, J. M. D.; Hauri, E. H.

    2014-06-01

    Lavas from Mangaia in the Cook-Austral island chain, Polynesia, define an HIMU (or high μ, where μ=U238/Pb204) global isotopic end-member among ocean island basalts (OIB) with the highest 206,207,208Pb/204Pb. This geochemical signature is interpreted to reflect a recycled oceanic crust component in the mantle source. Mass independently fractionated (MIF) sulfur isotopes indicate that Mangaia lavas sampled recycled Archean material that was once at the Earth's surface, likely hydrothermally-modified oceanic crust. Recent models have proposed that crust that is subducted and then returned to the surface in a mantle plume is expected to transform to pyroxenite/eclogite during transit through the mantle. Here we examine this hypothesis for Mangaia using high-precision electron microprobe analysis on olivine phenocrysts. Contrary to expectations of a crustal component and, hence pyroxenite, results show a mixed peridotite and pyroxenite source, with peridotite dominating. If the isotopic compositions were inherited from subduction of recycled oceanic crust, our work shows that this source has phantom-like properties in that it can have its lithological identity destroyed while its isotope ratios are preserved. This may occur by partial melting of the pyroxenite and injection of its silicic melts into the surrounding mantle peridotite, yielding a refertilized peridotite. Evidence from one sample reveals that not all pyroxenite in the melting region was destroyed. Identification of source lithology using olivine phenocryst chemistry can be further compromised by magma chamber fractional crystallization, recharge, and mixing. We conclude that the commonly used terms mantle “heterogeneities” and “streaks” are ambiguous, and distinction should be made of its lithological and isotopic properties.

  13. Analysis of C/E results of fission rate ratio measurements in several fast lead VENUS-F cores

    Directory of Open Access Journals (Sweden)

    Kochetkov Anatoly

    2017-01-01

    Full Text Available During the GUINEVERE FP6 European project (2006–2011, the zero-power VENUS water-moderated reactor was modified into VENUS-F, a mock-up of a lead cooled fast spectrum system with solid components that can be operated in both critical and subcritical mode. The Fast Reactor Experiments for hybrid Applications (FREYA FP7 project was launched in 2011 to support the designs of the MYRRHA Accelerator Driven System (ADS and the ALFRED Lead Fast Reactor (LFR. Three VENUS-F critical core configurations, simulating the complex MYRRHA core design and one configuration devoted to the LFR ALFRED core conditions were investigated in 2015. The MYRRHA related cores simulated step by step design peculiarities like the BeO reflector and in pile sections. For all of these cores the fuel assemblies were of a simple design consisting of 30% enriched metallic uranium, lead rodlets to simulate the coolant and Al2O3 rodlets to simulate the oxide fuel. Fission rate ratios of minor actinides such as Np-237, Am-241 as well as Pu-239, Pu-240, Pu-242 and U-238 to U-235 were measured in these VENUS-F critical assemblies with small fission chambers in specially designed locations, to determine the spectral indices in the different neutron spectrum conditions. The measurements have been analyzed using advanced computational tools including deterministic and stochastic codes and different nuclear data sets like JEFF-3.1, JEFF-3.2, ENDF/B7.1 and JENDL-4.0. The analysis of the C/E discrepancies will help to improve the nuclear data in the specific energy region of fast neutron reactor spectra.

  14. Geochemical investigations by the U.S. Geological Survey on uranium mining, milling, and environmental restoration

    Science.gov (United States)

    Landa, Edward R.; Cravotta, Charles A.; Naftz, David L.; Verplanck, Philip L.; Nordstrom, D. Kirk; Zielinski, Robert A.

    2000-01-01

    Recent research by the U.S. Geological Survey has characterized contaminant sources and identified important geochemical processes that influence transport of radionuclides from uranium mining and milling wastes. 1) Selective extraction studies indicated that alkaline earth sulfates and hydrous ferric oxides are important hosts of 226Ra in uranium mill tailings. The action of sulfate-reducing and ironreducing bacteria on these phases was shown to enhance release of radium, and this adverse result may temper decisions to dispose of uranium mill tailings in anaerobic environments. 2) Field studies have shown that although surface-applied sewage sludge/wood chip amendments aid in revegetating pyritic spoil, the nitrogen in sludge leachate can enhance pyrite oxidation, acidification of groundwater, and the consequent mobilization of metals and radionuclides. 3) In a U.S. Environmental Protection Agencyfunded study, three permeable reactive barriers consisting of phosphate-rich material, zero-valent iron, or amorphous ferric oxyhydroxide have been installed at an abandoned uranium upgrader facility near Fry Canyon, UT. Preliminary results indicate that each of the permeable reactive barriers is removing the majority of the uranium from the groundwater. 4) Studies on the geochemistry of rare earth elements as analogues for actinides such as uranium and thorium in acid mine drainage environments indicate high mobility under acid-weathering conditions but measurable attenuation associated with iron and aluminum colloid formation. Mass balances from field and laboratory studies are being used to quantify the amount of attenuation. 5) A field study in Colorado demonstrated the use of 234U/238U isotopic ratio measurements to evaluate contamination of shallow groundwater with uranium mill effluent.

  15. Heavy ion linear accelerator for radiation damage studies of materials

    Energy Technology Data Exchange (ETDEWEB)

    Kutsaev, Sergey V.; Mustapha, Brahim; Ostroumov, Peter N.; Nolen, Jerry; Barcikowski, Albert; Pellin, Michael; Yacout, Abdellatif

    2017-03-01

    A new eXtreme MATerial (XMAT) research facility is being proposed at Argonne National Laboratory to enable rapid in situ mesoscale bulk analysis of ion radiation damage in advanced materials and nuclear fuels. This facility combines a new heavy-ion accelerator with the existing high-energy X-ray analysis capability of the Argonne Advanced Photon Source. The heavy-ion accelerator and target complex will enable experimenters to emulate the environment of a nuclear reactor making possible the study of fission fragment damage in materials. Material scientists will be able to use the measured material parameters to validate computer simulation codes and extrapolate the response of the material in a nuclear reactor environment. Utilizing a new heavy-ion accelerator will provide the appropriate energies and intensities to study these effects with beam intensities which allow experiments to run over hours or days instead of years. The XMAT facility will use a CW heavy-ion accelerator capable of providing beams of any stable isotope with adjustable energy up to 1.2 MeV/u for U-238(50+) and 1.7 MeV for protons. This energy is crucial to the design since it well mimics fission fragments that provide the major portion of the damage in nuclear fuels. The energy also allows damage to be created far from the surface of the material allowing bulk radiation damage effects to be investigated. The XMAT ion linac includes an electron cyclotron resonance ion source, a normal-conducting radio-frequency quadrupole and four normal-conducting multi-gap quarter-wave resonators operating at 60.625 MHz. This paper presents the 3D multi-physics design and analysis of the accelerating structures and beam dynamics studies of the linac.

  16. Validation of CENDL and JEFF evaluated nuclear data files for TRIGA calculations through the analysis of integral parameters of TRX and BAPL benchmark lattices of thermal reactors

    Energy Technology Data Exchange (ETDEWEB)

    Uddin, M.N. [Department of Physics, Jahangirnagar University, Dhaka (Bangladesh); Sarker, M.M. [Reactor Physics and Engineering Division, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, GPO Box 3787, Dhaka 1000 (Bangladesh); Khan, M.J.H. [Reactor Physics and Engineering Division, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, GPO Box 3787, Dhaka 1000 (Bangladesh)], E-mail: jahirulkhan@yahoo.com; Islam, S.M.A. [Department of Physics, Jahangirnagar University, Dhaka (Bangladesh)

    2009-10-15

    The aim of this paper is to present the validation of evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 through the analysis of the integral parameters of TRX and BAPL benchmark lattices of thermal reactors for neutronics analysis of TRIGA Mark-II Research Reactor at AERE, Bangladesh. In this process, the 69-group cross-section library for lattice code WIMS was generated using the basic evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 with the help of nuclear data processing code NJOY99.0. Integral measurements on the thermal reactor lattices TRX-1, TRX-2, BAPL-UO{sub 2}-1, BAPL-UO{sub 2}-2 and BAPL-UO{sub 2}-3 served as standard benchmarks for testing nuclear data files and have also been selected for this analysis. The integral parameters of the said lattices were calculated using the lattice transport code WIMSD-5B based on the generated 69-group cross-section library. The calculated integral parameters were compared to the measured values as well as the results of Monte Carlo Code MCNP. It was found that in most cases, the values of integral parameters show a good agreement with the experiment and MCNP results. Besides, the group constants in WIMS format for the isotopes U-235 and U-238 between two data files have been compared using WIMS library utility code WILLIE and it was found that the group constants are identical with very insignificant difference. Therefore, this analysis reflects the validation of evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 through benchmarking the integral parameters of TRX and BAPL lattices and can also be essential to implement further neutronic analysis of TRIGA Mark-II research reactor at AERE, Dhaka, Bangladesh.

  17. Pb-210 deposition measured in rainfall in Sao Paulo, SP-Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Damatto, Sandra R.; Frujuele, Jonatan V.; Souza, Joseilton M.; Santos, Levi F., E-mail: damatto@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Lab. de Radiometria Ambiental

    2013-07-01

    Pb-210 (T{sub 1/2} = 22.3 y), a natural radionuclide from U-238 serie can be found in the atmosphere, as a product of {sup 222}Rn decay that emanates from the ground, where its atoms become rapidly fixed to aerosols and return to the earth as dry fallout or are washed out in the rain. This natural radionuclide has been widely used as an atmospheric tracer, to determine the aerosol residence time as well as chronometers in the environment. Pb-210 was measured during a period of two years, 2011 to 2013, in samples of rainfall in all the rainy events that occurred at the Instituto de Pesquisas Energeticas e Nucleares (IPEN) campus (23 deg 33’59.24” S - 46 deg 44’15.63” O at 760 m above sea level) which is located in the city of Sao Paulo, in the state of Sao Paulo, Brazil. Pb-210 concentration was measured in a total of 123 rainy events by beta gross counting in a low background gas flow proportional detector, after radiochemistry procedure. The results obtained were correlated to seasons and rainfall. The concentrations of {sup 210}Pb in rainfall varied from the minimum detectable activity, 4.9 mBq L{sup -1} to 1408± 43 mBq L{sup -1}. The highest concentrations were obtained in the months of winter and the lowest in summer. The monthly depositional flux of {sup 210}Pb, varied from 4.03 Bq m{sup -2} month{sup -1} to 46.4 Bq m{sup -2} month{sup -1}presenting a strong correlation with the amount of precipitation and hence showing seasonal trends. (author)

  18. Uranium uptake history, open-system behaviour and uranium-series ages of fossil Tridacna gigas from Huon Peninsula, Papua New Guinea

    Science.gov (United States)

    Ayling, Bridget F.; Eggins, Stephen; McCulloch, Malcolm T.; Chappell, John; Grün, Rainer; Mortimer, Graham

    2017-09-01

    Molluscs incorporate negligible uranium into their skeleton while they are living, with any uranium uptake occurring post-mortem. As such, closed-system U-series dating of molluscs is unlikely to provide reliable age constraints for marine deposits. Even the application of open-system U-series modelling is challenging, because uranium uptake and loss histories can affect time-integrated uranium distributions and are difficult to constrain. We investigate the chemical and isotopic distribution of uranium in fossil Tridacna gigas (giant clams) from Marine Isotope Stage (MIS) 5e (128-116 ka) and MIS 11 (424-374 ka) reefs at Huon Peninsula in Papua New Guinea. The large size of the clams enables detailed chemical and isotopic mapping of uranium using LA-ICPMS and LA-MC-ICPMS techniques. Within each fossil Tridacna specimen, marked differences in uranium concentrations are observed across the three Tridacna growth zones (outer, inner, hinge), with the outer and hinge zones being relatively enriched. In MIS 5e and MIS 11 Tridacna, the outer and hinge zones contain approximately 1 ppm and 5 ppm uranium respectively. In addition to uptake of uranium, loss of uranium appears prevalent, especially in the MIS 11 specimens. The effect of uranium loss is to elevate measured [230Th/238U] values with little effect on [234U/238U] values. Closed-system age estimates are on average 50% too young for the MIS 5e Tridacna, and 25% too young for the MIS 11 Tridacna. A complex, multi-stage uptake and loss history is interpreted for the fossil Tridacna and we demonstrate that they cannot provide independent, reliable geochronological controls on the timing of past reef growth at Huon Peninsula.

  19. Evaluation of total effective dose due to certain environmentally placed naturally occurring radioactive materials using a procedural adaptation of RESRAD code.

    Science.gov (United States)

    Beauvais, Z S; Thompson, K H; Kearfott, K J

    2009-07-01

    Due to a recent upward trend in the price of uranium and subsequent increased interest in uranium mining, accurate modeling of baseline dose from environmental sources of radioactivity is of increasing interest. Residual radioactivity model and code (RESRAD) is a program used to model environmental movement and calculate the dose due to the inhalation, ingestion, and exposure to radioactive materials following a placement. This paper presents a novel use of RESRAD for the calculation of dose from non-enhanced, or ancient, naturally occurring radioactive material (NORM). In order to use RESRAD to calculate the total effective dose (TED) due to ancient NORM, a procedural adaptation was developed to negate the effects of time progressive distribution of radioactive materials. A dose due to United States' average concentrations of uranium, actinium, and thorium series radionuclides was then calculated. For adults exposed in a residential setting and assumed to eat significant amounts of food grown in NORM concentrated areas, the annual dose due to national average NORM concentrations was 0.935 mSv y(-1). A set of environmental dose factors were calculated for simple estimation of dose from uranium, thorium, and actinium series radionuclides for various age groups and exposure scenarios as a function of elemental uranium and thorium activity concentrations in groundwater and soil. The values of these factors for uranium were lowest for an adult exposed in an industrial setting: 0.00476 microSv kg Bq(-1) y(-1) for soil and 0.00596 microSv m(3) Bq(-1) y(-1) for water (assuming a 1:1 234U:238U activity ratio in water). The uranium factors were highest for infants exposed in a residential setting and assumed to ingest food grown onsite: 34.8 microSv kg Bq(-1) y(-1) in soil and 13.0 microSv m(3) Bq(-1) y(-1) in water.

  20. Analysis of C/E results of fission rate ratio measurements in several fast lead VENUS-F cores

    Science.gov (United States)

    Kochetkov, Anatoly; Krása, Antonín; Baeten, Peter; Vittiglio, Guido; Wagemans, Jan; Bécares, Vicente; Bianchini, Giancarlo; Fabrizio, Valentina; Carta, Mario; Firpo, Gabriele; Fridman, Emil; Sarotto, Massimo

    2017-09-01

    During the GUINEVERE FP6 European project (2006-2011), the zero-power VENUS water-moderated reactor was modified into VENUS-F, a mock-up of a lead cooled fast spectrum system with solid components that can be operated in both critical and subcritical mode. The Fast Reactor Experiments for hybrid Applications (FREYA) FP7 project was launched in 2011 to support the designs of the MYRRHA Accelerator Driven System (ADS) and the ALFRED Lead Fast Reactor (LFR). Three VENUS-F critical core configurations, simulating the complex MYRRHA core design and one configuration devoted to the LFR ALFRED core conditions were investigated in 2015. The MYRRHA related cores simulated step by step design peculiarities like the BeO reflector and in pile sections. For all of these cores the fuel assemblies were of a simple design consisting of 30% enriched metallic uranium, lead rodlets to simulate the coolant and Al2O3 rodlets to simulate the oxide fuel. Fission rate ratios of minor actinides such as Np-237, Am-241 as well as Pu-239, Pu-240, Pu-242 and U-238 to U-235 were measured in these VENUS-F critical assemblies with small fission chambers in specially designed locations, to determine the spectral indices in the different neutron spectrum conditions. The measurements have been analyzed using advanced computational tools including deterministic and stochastic codes and different nuclear data sets like JEFF-3.1, JEFF-3.2, ENDF/B7.1 and JENDL-4.0. The analysis of the C/E discrepancies will help to improve the nuclear data in the specific energy region of fast neutron reactor spectra.

  1. Evaluation of diffusive gradients in thin-films using a Diphonix® resin for monitoring dissolved uranium in natural waters.

    Science.gov (United States)

    Turner, Geraldine S C; Mills, Graham A; Burnett, Jonathan L; Amos, Sean; Fones, Gary R

    2015-01-07

    Commercially available Diphonix(®) resin (TrisKem International) was evaluated as a receiving phase for use with the diffusive gradients in thin-films (DGT) passive sampler for measuring uranium. This resin has a high partition coefficient for actinides and is used in the nuclear industry. Other resins used as receiving phases with DGT for measuring uranium have been prone to saturation and significant chemical interferences. The performance of the device was evaluated in the laboratory and in field trials. In laboratory experiments uptake of uranium (all 100% efficiency) by the resin was unaffected by varying pH (4-9), ionic strength (0.01-1.00 M, as NaNO3) and varying aqueous concentrations of Ca(2+) (100-500 mg L(-1)) and HCO3(-) (100-500 mg L(-1)). Due to the high partition coefficient of Diphonex(®), several elution techniques for uranium were evaluated. The optimal eluent mixture was 1M NaOH/1M H2O2, eluting 90% of the uranium from the resin. Uptake of uranium was linear (R(2)=0.99) over time (5 days) in laboratory experiments using artificial freshwater showing no saturation effects of the resin. In field deployments (River Lambourn, UK) the devices quantitatively accumulated uranium for up to 7 days. In both studies uptake of uranium matched that theoretically predicted for the DGT. Similar experiments in seawater did not follow the DGT theoretical uptake and the Diphonix(®) appeared to be capacity limited and also affected by matrix interferences. Isotopes of uranium (U(235)/U(238)) were measured in both environments with a precision and accuracy of 1.6-2.2% and 1.2-1.4%, respectively. This initial study shows the potential of using Diphonix(®)-DGT for monitoring of uranium in the aquatic environment. Copyright © 2014. Published by Elsevier B.V.

  2. The radiochemical contamination (210Po and 238U of zone around phosphogypsum waste heap in Wiślinka (northern Poland

    Directory of Open Access Journals (Sweden)

    Boryło A.

    2013-04-01

    Full Text Available The aim of this work was the determination of the impact of phosphogypsum waste heap in Wiślinka (northern Poland for radiological protection of zone around waste heap. The activity of 210Po, 234U, and 238U were measured using an alpha spectrometer. The values of uranium and polonium concentration in water with immediate area of waste heap are considerably higher than in the waters of the Martwa Wisła river. The values of activity ratio 234U/238U are approximately about one in the phosphogypsum (0.97±0.05 and in the water of retention reservoir and pumping station (0.92±0.01 and 0.99±0.08, while in the water from the Martwa Wisła river they are slightly higher than one (1.03±0.07 and 1.17±0.06. In the analyzed plants species the highest amounts of polonium and uranium were found in ruderal plants samples as well as hygrophilous plant samples. The more amounts of 210Po and 238U radionuclides were accumulated mainly in the roots of the analyzed plant species. The significant source of polonium and uranium in the natural environment is dry and wet atmospheric fallout in the immediate vicinity of phosphogypsum waste heap and the transfer via root for distant areas. The general conclusion of realized study is higher influence of phosphogypsum on radioactive contamination of environmental zone around heap waste in Wiślinka (northern Poland.

  3. Validation of minor actinides fission neutron cross-sections

    Directory of Open Access Journals (Sweden)

    Pešić Milan P.

    2015-01-01

    Full Text Available Verification of neutron fission cross-sections of minor actinides from some recently available evaluated nuclear data libraries was carried out by comparison of the reaction rates calculated by the MCNP6.1 computer code to the experimental values. The experimental samples, containing thin layers of 235U, 237Np, 238,239,240,241Pu, 242mAm, 243Cm, 245Cm, and 247Cm, deposited on metal support and foils of 235U (pseudo-alloy 27Al + 235U, 238U, natIn, 64Zn, 27Al, and multi-component sample alloy 27Al + 55Mn + natCu + natLu + 197Au, were irradiated in the channels of the tank containing fluorine salts 0.52NaF + 0.48ZrF4, labelled as the Micromodel Salt Blanket, inserted in the lattice centre of the MAKET heavy water critical assembly at the Institute for Theoretical and Experimental Physics, Moscow. This paper is a continuation of earlier initiated scientific-research activities carried out for validation of the evaluated fission cross-sections of actinides that were supposed to be used for the quality examination of the fuel design of the accelerator driven systems or fast reactors, and consequently, determination of transmutation rates of actinides, and therefore, determination of operation parameters of these reactor facilities. These scientific-research activities were carried out within a frame of scientific projects supported by the International Science and Technology Center and the International Atomic Energy Agency co-ordinated research activities, from 1999 to 2010. Obtained results confirm that further research is needed in evaluations in order to establish better neutron cross-section data for the minor actinides and selected nuclides which could be used in the accelerator driven systems or fast reactors.

  4. The last interglacial period at Guantanamo Bay, Cuba and an estimate of late Quaternary tectonic uplift rate in a strike-slip regime

    Science.gov (United States)

    Schweig, E. S.; Muhs, D. R.; Simmons, K. R.; Halley, R. B.

    2015-12-01

    Guantanamo Bay, Cuba is an area dominated by a strike-slip tectonic regime and is therefore expected to have very low Quaternary uplift rates. We tested this hypothesis by study of an unusually well preserved emergent reef terrace around the bay. Up to 12 m of unaltered, growth-position reef corals are exposed at about 40 sections examined around ˜40 km of coastline. Maximum reef elevations in the protected, inner part of the bay are ˜11-12 m, whereas outer-coast shoreline angles of wave-cut benches are as high as ˜14 m. Fifty uranium-series analyses of unrecrystallized corals from six localities yield ages ranging from ˜134 ka to ˜115 ka, when adjusted for small biases due to slightly elevated initial 234U/238U values. Thus, ages of corals correlate this reef to the peak of the last interglacial period, marine isotope stage (MIS) 5.5. Previously, we dated the Key Largo Limestone to the same high-sea stand in the tectonically stable Florida Keys. Estimates of paleo-sea level during MIS 5.5 in the Florida Keys are ~6.6 to 8.3 m above present. Assuming a similar paleo-sea level in Cuba, this yields a long-term tectonic uplift rate of 0.04-0.06 m/ka over the past ~120 ka. This estimate supports the hypothesis that the tectonic uplift rate should be low in this strike-slip regime. Nevertheless, on the southeast coast of Cuba, east of our study area, we have observed flights of multiple marine terraces, suggesting either (1) a higher uplift rate or (2) an unusually well-preserved record of pre-MIS 5.5 terraces not observed at Guantanamo Bay.

  5. GENERAL CHARACTERISTICS OF SELECTED BOTTLED MINERAL WATERS, MINERAL AND THERAPEUTIC WATERS IN BELARUS

    Directory of Open Access Journals (Sweden)

    Natalia Ushko

    2017-04-01

    Full Text Available This work presents the physical properties, chemical composition, natural radionuclides’ concentrations and the relative values of δ18O, δ2H of selected bottled mineral, mineral and therapeutic waters of some water intakes localized at different therapeutic centers in Belarus. The water samples were collected in the period from January 2012 to June 2015 and analyzed at the Faculty of Geology, Geophysics and Environmental Protection and Faculty of Physics and Applied Computer Science laboratories, AGH University of Science and Technology in Kraków Poland. The results show that the dominating ions in the majority of waters are Cl-, SO42-, Na+ and Ca2+ , the total dissolved solids (TDS of the investigated waters ranges from several hundred mg/L to near 150 g/L, pH from 6.6 to 9.2 and Eh from -283 to 259 mV. The radium isotopes concentration ranges from below the limit of detection to 17 Bq/L, and the specific activity of 228Ra is often higher than those of 226Ra. The uranium concentration range from below 0.5 mBq/L to 75 mBq/L for 238U and to 300 mBq/L for 234U. In some waters the uranium activity ratio (234U/238U is very high. The tritium concentrations are below 1.1 UT, δ18O range from -10.9‰ to -7.8‰ and δ2H from -84‰ to -59.4‰. These values indicate that groundwaters are dominated by components which were recharged during the Holocene. Due to the presence of specific elements such as iron, bromine and radon, as well as hydrogen sulfide, some mineral waters are classified as therapeutic.

  6. Geochemical Analyses of Rock, Sediment, and Water from the Region In and Around the Tuba City Landfill, Tuba City, Arizona

    Science.gov (United States)

    Johnson, Raymond H.; Wirt, Laurie

    2009-01-01

    The Tuba City Landfill (TCL) started as an unregulated waste disposal site in the 1940s and was administratively closed in 1997. Since the TCL closure, radionuclides have been detected in the shallow ground water. In 2006, the Bureau of Indian Affairs (BIA) contracted with the U.S. Geological Survey (USGS) to better understand the source of radionuclides in the ground water at the TCL compared to the surrounding region. This report summarizes those data and presents interpretations that focus on the geochemistry in the rocks and water from the Tuba City region. The TCL is sited on Navajo Sandstone above the contact with the Kayenta Formation. These formations are not rich in uranium but generally are below average crustal abundance values for uranium. Uranium ores in the area were mined nearby in the Chinle Formation and processed at the Rare Metals mill (RMM). Regional samples of rock, sediment, leachates, and water were collected in and around the TCL site and analyzed for major and minor elements, 18O, 2H, 3H, 13C, 14C,34S, 87Sr, and 234U/238U, as appropriate. Results of whole rock and sediment samples, along with leachates, suggest the Chinle Formation is a major source of uranium and other trace elements in the area. Regional water samples indicate that some of the wells within the TCL site have geochemical signatures that are different from the regional springs and surface water. The geochemistry from these TCL wells is most similar to leachates from the Chinle Formation rocks and sediments. Isotope samples do not uniquely identify TCL-derived waters, but they do provide a useful indicator for shallow compared to deep ground-water flow paths and general rock/water interaction times. Information in this report provides a comparison between the geochemistry within the TCL and in the region as a whole.

  7. Influence of particle composition on thorium cycling along the U.S. GEOTRACES North Atlantic Section

    Science.gov (United States)

    Lerner, Paul; Marchal, Olivier; Lam, Phoebe

    2017-04-01

    Our current knowledge about the behaviour of particle-reactive substances in the ocean stems largely from measurements of thorium radio-isotopes (Th-228, Th-230, Th-234) on seawater samples. The oceanic Th database has increased dramatically over the recent years, thanks in particular to the GEOTRACES program, an international study of the marine biogeochemical cycles of trace elements and their isotopes. Here we present an analysis of data collected at several stations of the U.S. GEOTRACES North Atlantic section (section GA03). Data originating from eleven stations situated west and east of the Middle-Atlantic Ridge are analyzed. First, at each station, the rate parameters of a single-particle class model of Th and particle cycling in the ocean water column are estimated from a least-squares fit to an eclectic data set, including (i) measurements of Th-228, Th-230, Th-234 activities in different size fractions, (ii) measurements of particle concentration, and (iii) measurements, or observational estimates, of the activities of the radio-active parents Ra-228, U-234, and U-238. Among our most salient results is a significant decrease in the apparent rate constant of Th adsorption (k1) with depth, with maxima in the meso-pelagic zone (ca. 100 - 1000 m) and minima below, at most stations. Second, we explore whether our k1 estimates can be related to changes in particle composition, both along the water column and laterally along GA03. We apply (i) multiple linear regression to quantify the amount of variance in k1 that can be explained by linear regression against particle composition data, and (ii) relative importance analysis to determine the relative contribution of different particulate phases to the explained variance in k1. Finally, the implications of our results for the interpretation of field Th isotope data and for the description of particle scavenging in ocean-biogeochemistry models are clarified.

  8. Determination of natural radioactivity in irrigation water of drilled wells in northwestern Saudi Arabia.

    Science.gov (United States)

    Alkhomashi, N; Al-Hamarneh, Ibrahim F; Almasoud, Fahad I

    2016-02-01

    The levels of natural radiation in bedrock groundwater extracted from drilled wells in selected farms in the northwestern part of Saudi Arabia were addressed. The investigated waters form a source of irrigation for vegetables, agricultural crops, wheat, and alfalfa to feed livestock consumed by the general public. Information about water radioactivity in this area is not available yet. Therefore, this study strives to contribute to the quality assessment of the groundwater of these wells that are drilled into the non-renewable Saq sandstone aquifer. Hence, gross alpha and beta activities as well as the concentrations of (224)Ra, (226)Ra, (228)Ra, (234)U, (238)U, and U(total) were measured, compared to national and international limits and contrasted with data quoted from the literature. Correlations between the activities of the analyzed radionuclides were discussed. The concentrations of gross alpha and beta activities as well as (228)Ra were identified by liquid scintillation counting whereas alpha spectrometry was used to determine (224)Ra, (226)Ra, (234)U and (238)U after separation from the matrix by extraction chromatography. The mean activity concentrations of gross α and β were 3.15 ± 0.26 Bq L(-1) and 5.39 ± 0.44 Bq L(-1), respectively. Radium isotopes ((228)Ra and (226)Ra) showed mean concentrations of 3.16 ± 0.17 Bq L(-1) and 1.12 ± 0.07 Bq L(-1), respectively, whereas lower levels of uranium isotopes ((234)U and (238)U) were obtained. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Radioactivity in honey of the central Italy.

    Science.gov (United States)

    Meli, Maria Assunta; Desideri, Donatella; Roselli, Carla; Feduzi, Laura; Benedetti, Claudio

    2016-07-01

    Natural radionuclides and (137)Cs in twenty seven honeys produced in a region of the Central Italy were determined by alpha ((235)U, (238)U, (210)Po, (232)Th and (228)Th) and gamma spectrometry ((137)Cs, (40)K, (226)Ra and (228)Ra). The study was carried out in order to estimate the background levels of natural ((40)K, (238)U and (232)Th and their progeny) and artificial radionuclides ((137)Cs) in various honey samples, as well as to compile a data base for radioactivity levels in that region. (40)K showed a mean activity of 28.1±23.0Bqkg(-1) with a range of 7.28-101Bqkg(-1). The mean of (210)Po activity resulted 0.40±0.46Bqkg(-1) with a range of 0.03-1.98Bqkg(-1). The mean of (238)U activity resulted 0.020±0.010Bqkg(-1). (226)Ra and (228)Ra resulted always <0.34 and <0.57Bqkg(-1) respectively, (235)U, (228)Th and (232)Th were always <0.007Bqkg(-1). (137)Cs resulted <0.10Bqkg(-1) in all samples. The committed effective doses due to (210)Po from ingestion of honey for infants, children and adults account for 0.002-5.13% of the natural radiation exposure in Italy. The honeys produced in Central Italy were of good quality in relation to the studied parameters, confirming the general image of a genuine and healthy food associated to this traditional products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Thermal History of the Felsite Unit, Geysers Geothermal Field, From Thermal Modeling of 40Ar/39Ar Incremental Heating Data

    Energy Technology Data Exchange (ETDEWEB)

    T. M. Harrison (U of California); G. B. Dalrymple (Oregon State U); J. B. Hulen (U of Utah); M. A. Lanphere; M. Grove; O. M. Lovera

    1999-08-19

    An Ar-40/Ar-39 and U-Pb study was performed of the Geysers plutonic complex of the Geysers Geothermal Field in California. Sixty-nine ion microprobe spot analyses of zircons from four granite samples from the plutonic complex that underlies the Geysers geothermal field yielded Pb-207/Pb-206 vs. U-238/Pb-206 concordia ages ranging from 1.13 {+-} 0.04 Ma to 1.25 {+-} 0.04 Ma. The U-Pb ages coincide closely with Ar-40/Ar-39 age spectrum plateau and ''terminal'' ages from coexisting K-feldspars and with the eruption ages of overlying volcanic rocks. The data indicate that the granite crystallized at 1.18 Ma and had cooled below 350 C by {approximately}0.9-1.0 Ma. Interpretation of the feldspar Ar-40/Ar-39 age data using multi-diffusion domain theory indicates that post-emplacement rapid cooling was succeeded either by slower cooling from 350-300 C between 1.0 and 0.4 Ma or transitory reheating to 300-350 C at about 0.4-0.6 Ma. Heat flow calculations constrained with K-feldspar thermal histories and the pre sent elevated regional heal flow anomaly demonstrate that appreciable heat input from sources external to the known Geysers plutonic complex is required to maintain the geothermal system. This requirement is satisfied by either a large, underlying, convecting magma chamber (now solidified) emplaced at 1.2 Ma or episodic intrusion of smaller bodies from 1.2-0.6 Ma.

  11. Uranium-series comminution ages of continental sediments: Case study of a Pleistocene alluvial fan

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Victoria E.; DePaolo, Donald J.; Christensen, John N.

    2010-04-30

    Obtaining quantitative information about the timescales associated with sediment transport, storage, and deposition in continental settings is important but challenging. The uranium-series comminution age method potentially provides a universal approach for direct dating of Quaternary detrital sediments, and can also provide estimates of the sediment transport and storage timescales. (The word"comminution" means"to reduce to powder," reflecting the start of the comminution age clock as reduction of lithic parent material below a critical grain size threshold of ~;;50 mu m.) To test the comminution age method as a means to date continental sediments, we applied the method to drill-core samples of the glacially-derived Kings River Fan alluvial deposits in central California. Sediments from the 45 m core have independently-estimated depositional ages of up to ~;;800 ka, based on paleomagnetism and correlations to nearby dated sediments. We characterized sequentially-leached core samples (both bulk sediment and grain size separates) for U, Nd, and Sr isotopes, grain size, surface texture, and mineralogy. In accordance with the comminution age model, where 234U is partially lost from small sediment grains due to alpha recoil, we found that (234U/238U) activity ratios generally decrease with age, depth, and specific surface area, with depletions of up to 9percent relative to radioactive equilibrium. The resulting calculated comminution ages are reasonable, although they do not exactly match age estimates from previous studies and also depend on assumptions about 234U loss rates. The results indicate that the method may be a significant addition to the sparse set of available tools for dating detrital continental sediments, following further refinement. Improving the accuracy of the method requires more advanced models or measurements for both the recoil loss factor fa and weathering effects. We discuss several independent methods for obtaining fa on individual samples

  12. Isotope ratio characteristics and sensitivity for uranium determinations using a liquid sampling-atmospheric pressure glow discharge ion source coupled to an Orbitrap mass analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Hoegg, Edward D.; Barinaga, Charles J.; Hager, George J.; Hart, Garret L.; Koppenaal, David W.; Marcus, R. Kenneth

    2016-01-01

    Abstract The continued development of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma as an ion source for diverse, elemental/isotopic analysis applications continues. To this end, characterization of the capabilities in performing precise and accurate isotope ratio (IR) determinations is essential. Based on past experience with the Thermo Exactive Orbitrap mass analyzer, the LS-APGD was interfaced with this instrument for these tests. While the Orbitrap platform has demonstrated excellent mass resolution and accuracy in “organic” mass spectrometry (MS) applications, work using an Orbitrap for IR analysis is very sparse. These efforts build off previous work in this coupling, where the importance of a few of the LS-APGD discharge parameters and Orbitrap data acquisition methods on IR precision and accuracy were probed. Presented here are the results of a study that evaluated the analytical precision for natural uranium sample (assumed 235U/238U = 0.0072) determinations. The instrumental parameters evaluated include the number of microscans and scans making up a data acquisition set, uranium concentration/signal level, sample make-up, and Fourier transform digitization window. Ultimately, a precision of 0.41% relative standard deviation (RSD) can be achieved for a single determination, with a reproducibility of 1.63 %RSD over 10 separate analytical measurements. A preliminary study of matrix effects on IR measurements of U is presented, highlighting the importance of pre-mass selection before injection into the Orbitrap. The analytical system sensitivity is suggested with the ability to produce a calibration function having an R2 value of >0.99 over a range of 4 orders of magnitude of concentration (~1 – 1000 ng mL-1). These efforts demonstrate the very promising pairing of the LS-APGD ionization source and the Orbitrap, pointing as well to definitive paths forward to better utilize both components in high quality isotope ratio

  13. U-series vs 14C ages of deep-sea corals from the southern Labrador Sea: Sporadic development of corals and geochemical processes hampering estimation of ambient water ventilation ages

    Science.gov (United States)

    Hillaire-Marcel, Claude; Maccali, Jenny; Ménabréaz, Lucie; Ghaleb, Bassam; Blénet, Aurélien; Edinger, Evan

    2017-04-01

    Deep-sea scleractinian corals were collected with the remotely operated ROPOS vehicle off Newfounland. Fossil specimens of Desmophyllum dianthus were raised from coral graveyards at Orphan Knoll (˜1700m depth) and Flemish cap (˜2200 m depth), while live specimens were collected directly in overlying steep rock slopes. D. dianthus has an aragonitic skeleton and is thus particularly suited for U-Th dating. We obtained > 70 U-series ages along with > 20 14C measurements. Results display a discrete age distribution with two age clusters: a Bølling-Allerød and Holocene cluster with > 20 samples, and a Marine Isotope Stage (MIS) 5c cluster with ˜50 samples. Only two samples lay outside these clusters, at ˜ 64 ka and at ˜181 ka. Contrary to the New England seamounts where coral presence seems to have been continue through the last 70 ka, Orphan Knoll and Flemish Cap graveyards are marked by the absence of preserved specimens from MIS 2 to MIS 4 and throughout MIS 6. For filter-feeding deep-sea corals, access to food-rich waters is essential. Hence the Holocene and MIS 5 clusters observed in the Labrador basin might represent intervals linked to high food availability, either through production in the overlying water column, more effectively in relation to particulate and dissolved organic carbon transport via an active Western Boundary Undercurrent. Comparison of 230Th-ages vs 14C-ages in order to document changes in ventilation ages of the ambient water masses is equivocal due to the presence of some diagenetic and/or initial 230Th-excess. In addition, discrete diagenetic U-fluxes can be documented from 234U/238U vs 230Th/238U data. They point to a recent winnowing of sediment overlying the fossil corals that we link to the Holocene intensification of the Western Boundary Undercurrent, which resulted in driving Fe-Mn coatings.

  14. Timescales of magma ascent and degassing and the role of crustal assimilation at Merapi volcano (2006-2010), Indonesia: Constraints from uranium-series and radiogenic isotopic compositions

    Science.gov (United States)

    Handley, H. K.; Reagan, M.; Gertisser, R.; Preece, K.; Berlo, K.; McGee, L. E.; Barclay, J.; Herd, R.

    2018-02-01

    We present new 238U-230Th-226Ra-210Pb-210Po, 87Sr/86Sr and 143Nd/144Nd isotopic data of whole-rock samples and plagioclase separates from volcanic deposits of the 2006 and 2010 eruptions at Merapi volcano, Java, Indonesia. These data are combined with available eruption monitoring, petrographic, mineralogical and Pb isotopic data to assess current theories on the cause of a recent transition from effusive dome-building (2006) to explosive (2010) activity at the volcano, as well as to further investigate the petrogenetic components involved in magma genesis and evolution. Despite the significant difference in eruption style, the 2006 and 2010 volcanic rocks show no significant difference in (238U/232Th), (230Th/232Th) and (226Ra/230Th) activity ratios, with all samples displaying U and Ra excesses. The 226Ra and 210Pb excesses observed in plagioclase separates from the 2006 and 2010 eruptions indicate that a proportion of the plagioclase grew within the decades preceding eruption. The 2006 and 2010 samples were depleted in 210Po relative to 210Pb ((210Po/210Pb)i < 1) at the time of eruption but were variably degassed (69%-100%), with the degree of 210Pb degassing strongly related to sample texture and eruption phase. In good agreement with several activity monitoring parameters, 210Po ingrowth calculations suggest that initial intrusion into the shallow magma plumbing system occurred several weeks to a few months prior to the initial 2010 eruption. The 2006 and 2010 samples show a wide range in (210Pb/226Ra) activity ratio within a single eruption at Merapi and are largely characterised by 210Pb deficits ((210Pb/226Ra) < 1). Assuming a model of complete radon degassing, the 210Pb deficits in the 2006 volcanic rocks indicate relatively longer degassing timescales of ∼2-4 years than those given by the 2010 samples of ∼0-3 years. The uranium-series and radiogenic isotopic data do not support greater crustal assimilation of carbonate material as the explanation for

  15. Chronology of Late Pleistocene glacier advances in the Rı´o Mendoza Valley, Argentina

    Science.gov (United States)

    Espizua, Lydia E.

    1999-10-01

    The Rı´o Mendoza valley at 33°S latitude has been repeatedly invaded by glaciers during the Late Pleistocene. Relative-age criteria, U-series ages, and thermoluminescense dating, permitted the glacial deposits to be separated into three mappable units, each less extensive than its predecessor, designed from oldest to youngest, Penitentes, Horcones and Almacenes drifts. Previous studies have shown that during the Penitentes advance the glacier system terminated at 2500 m, while during the subsequent Horcones advance, ice terminated at 2750 m and the Almacenes moraine reached 3250 m. A travertine layer overlying Penitentes till yielded 230Th/ 232Th ages of 38,300±5300, 24,200±2000 and 22,800±3100 yr B.P. This study focuses on dating interstadial sediments in the upper Rı´o Mendoza valley in order to constrain the ages of the drifts. A date was obtained from a composite stratigraphic profile based on exposures along the east side of the Rı´o de los Horcones Inferior valley, a tributary of the Rı´o de las Cuevas valley, which includes the Penitentes and Horcones tills separated by nonglacial sediments (silt, fine sand and clay), and are interpreted as representing the Penitentes-Horcones nonglacial interval. The fine quartz grains (4-11 μm) of these sediments were TL dated as 31,000±3100 yr. All these dates, which are minimum ages for the underlying Penitentes till, imply that the Penitentes ice advanced prior to the last glacial maximum and sometime before ca. 40,000 years ago. A minimum date for Horcones till comes from an exposure on the east side of the Rı´o de los Horcones Inferior valley where the Horcones and Almacenes tills are separated by sediments of nonglacial origin. The fine quartz grains (4-11 μm) of these sediments have been dated by TL as 15,000±2100 years ago. Almacenes till is inferred to represent a standstill or a readvance that occurred late during the Horcones glacier advance. These dates imply that the Penitentes advance may

  16. A radiological study of some ornamental stones: the bluish granites from Extremadura (Spain)

    Science.gov (United States)

    Pereira, D.; Neves, L.; Pereira, A.; Peinado, M.; Blanco, J. A.; Tejado, J. J.

    2012-02-01

    In the area of Trujillo (Extremadura, Spain) we have found a variety of striking bluish and secondary yellow granites outcropping within the Plasenzuela pluton. They are all quarried under different names and are characterized by leucocratic minerals in which a bluish phosphate is dispersed throughout the rock. Their physical and mechanical properties make these granites a perfect option for most applications as ornamental rocks. Within the pluton the radiological background is fairly homogeneous, with no significant differences between the gamma ray fluxes of the different facies. U (6.4 ± 0.51 ppm), Th (2.9 ± 0.47 ppm) and K2O (4.32 ± 0.26%) contents determined in the laboratory by gamma-ray spectrometry from representative samples are in good accordance with fast in situ measurements carried out with the same technique and also with conventional chemical analysis. Estimated activities for K-40, Ra-226 and Th-232 were, on average, 1022 ± 36 Bq kg-1, 84 ± 9 Bq kg-1 and 6.8 ± 1.6 Bq kg-1. On the basis of these results, the I index of EU technical document 112 was determined, with an average result of 0.66 ± 0.03. This suggests that the rock can be used with no restrictions for all types of construction purposes. Striking differences were observed between the blue facies and the yellow facies in radon exhalation tests from crushed material (0.03 Bq kg-1 vs. 0.20 Bq kg-1). Since both granites have similar uranium contents (6.3 ppm and 6.5 ppm, respectively), these results can probably be explained in terms of important differences in the mineralogical distribution of this chemical element, radon emanation being enhanced in the yellow facies. However, due to the ordinary use as ornamental stone, the yellow facies does not present a radiological risk in terms of excess effective dose due to internal exposure to radon.

  17. A radiological study of some ornamental stones: the bluish granites from Extremadura (Spain

    Directory of Open Access Journals (Sweden)

    D. Pereira

    2012-02-01

    Full Text Available In the area of Trujillo (Extremadura, Spain we have found a variety of striking bluish and secondary yellow granites outcropping within the Plasenzuela pluton. They are all quarried under different names and are characterized by leucocratic minerals in which a bluish phosphate is dispersed throughout the rock. Their physical and mechanical properties make these granites a perfect option for most applications as ornamental rocks. Within the pluton the radiological background is fairly homogeneous, with no significant differences between the gamma ray fluxes of the different facies. U (6.4 ± 0.51 ppm, Th (2.9 ± 0.47 ppm and K2O (4.32 ± 0.26% contents determined in the laboratory by gamma-ray spectrometry from representative samples are in good accordance with fast in situ measurements carried out with the same technique and also with conventional chemical analysis. Estimated activities for K-40, Ra-226 and Th-232 were, on average, 1022 ± 36 Bq kg−1, 84 ± 9 Bq kg−1 and 6.8 ± 1.6 Bq kg−1. On the basis of these results, the I index of EU technical document 112 was determined, with an average result of 0.66 ± 0.03. This suggests that the rock can be used with no restrictions for all types of construction purposes. Striking differences were observed between the blue facies and the yellow facies in radon exhalation tests from crushed material (0.03 Bq kg−1 vs. 0.20 Bq kg−1. Since both granites have similar uranium contents (6.3 ppm and 6.5 ppm, respectively, these results can probably be explained in terms of important differences in the mineralogical distribution of this chemical element, radon emanation being enhanced in the yellow facies. However, due to the ordinary use as ornamental stone, the yellow facies does not present a radiological risk in terms of excess effective dose due to internal exposure to radon.

  18. Boron isotope variations in Tonga-Kermadec-New Zealand arc lavas: Implications for the origin of subduction components and mantle influences

    Science.gov (United States)

    Leeman, William P.; Tonarini, Sonia; Turner, Simon

    2017-03-01

    The Tonga-Kermadec-New Zealand volcanic arc is an end-member of arc systems with fast subduction suggesting that the Tonga sector should have the coolest modern slab thermal structure on Earth. New data for boron concentration and isotopic composition are used to evaluate the contrasting roles of postulated subduction components (sediments and oceanic slab lithologies) in magma genesis. Major observations include: (a) Tonga-Kermadec volcanic front lavas are enriched in B (as recorded by B/Nb and similar ratios) and most have relatively high δ11B (>+4‰), whereas basaltic lavas from New Zealand have relatively low B/Nb and δ11B (back-arc, as observed elsewhere; and (d) low δ11B is observed in volcanic front samples from Ata, an anomalous sector where the back-arc Valu Fa Spreading Center impinges on the arc and the Louisville Seamount Chain is presently subducting. Otherwise, volcanic front lavas exhibit positive correlations for both B/Nb and δ11B with other plausible indicators of slab-derived fluid contributions (e.g., Ba/Nb, U/Th, (230Th/232Th) and 10Be/9Be), and with estimated degree of melting to produce the mafic lavas. Inferred B-enrichments in the arc magma sources are likely dominated by serpentinite domains deeper within the subducting slab (±altered oceanic crust), and B systematics are consistent with dominant transport by slab-derived aqueous fluids. Effects of this process are amplified by mantle wedge source depletion due to prior melt extraction.Plain Language SummaryBoron isotope and other geochemical data are used to evaluate contributions from subducted materials to magma sources for volcanoes of the Tonga-Kermadec-New Zealand volcanic arc. The data are used to estimate the composition of modified mantle sources for the arc magmas as well as the extent of melting to produce them. It is shown that the mantle was previously depleted in melt components, and then overprinted by B and other components from the subducting slab, predominantly by

  19. Subalkaline andesite from Valu Fa Ridge, a back-arc spreading center in southern Lau Basin: petrogenesis, comparative chemistry, and tectonic implications

    Science.gov (United States)

    Vallier, T.L.; Jenner, G.A.; Frey, F.A.; Gill, J.B.; Davis, A.S.; Volpe, A.M.; Hawkins, J.W.; Morris, J.D.; Cawood, Peter A.; Morton, J.L.; Scholl, D. W.; Rautenschlein, M.; White, W.M.; Williams, Ross W.; Stevenson, A.J.; White, L.D.

    1991-01-01

    Tholeiitic andesite was dredged from two sites on Valu Fa Ridge (VFR), a back-arc spreading center in Lau Basin. Valu Fa Ridge, at least 200 km long, is located 40-50 km west of the active Tofua Volcanic Arc (TVA) axis and lies about 150 km above the subducted oceanic plate. One or more magma chambers, traced discontinuously for about 100 km along the ridge axis, lie 3-4 km beneath the ridge. The mostly aphyric and glassy lavas had high volatile contents, as shown by the abundance and large sizes of vesicles. An extensive fractionation history is inferred from the high SiO2 contents and FeO* MgO ratios. Chemical data show that the VFR lavas have both volcanic arc and back-arc basin affinities. The volcanic arc characteristics are: (1) relatively high abundances of most alkali and alkaline earth elements; (2) low abundances of high field strength elements Nb and Ta; (3) high U/Th ratios; (4) similar radiogenic isotope ratios in VFR and TVA lavas, in particular the enrichment of 87Sr 86Sr relative to 206Pb 204Pb; (5) high 238U 230Th, 230Th 232Th, and 226Ra 230Th activity ratios; and (6) high ratios of Rb/Cs, Ba/Nb, and Ba/La. Other chemical characteristics suggest that the VFR lavas are related to MORB-type back-arc basin lavas. For example, VFR lavas have (1) lower 87Sr 86Sr ratios and higher 143Nd 144Nd ratios than most lavas from the TVA, except samples from Ata Island, and are similar to many Lau Basin lavas; (2) lower Sr/REE, Rb/Zr, and Ba/Zr ratios than in arc lavas; and (3) higher Ti, Fe, and V, and higher Ti/V ratios than arc lavas generally and TVA lavas specifically. Most characteristics of VFR lavas can be explained by mixing depleted mantle with either small amounts of sediment and fluids from the subducting slab and/or an older fragment of volcanic arc lithosphere. The eruption of subalkaline andesite with some arc affinities along a back-arc spreading ridge is not unique. Collision of the Louisville and Tonga ridges probably activated back-arc extension

  20. Distinguishing lower and upper crustal processes in magmas erupted during the buildup to the 7.7 ka climactic eruption of Mount Mazama, Crater Lake, Oregon, using 238U-230Th disequilibria

    Science.gov (United States)

    Ankney, Meagan E.; Johnson, Clark M.; Bacon, Charles R.; Beard, Brian L.; Jicha, Brian R.

    2013-08-01

    Uranium-series isotope ratios determined for 35 volcanic rocks and 4 glass separates erupted from ~36 to 4.8 ka at Mt. Mazama, Crater Lake, Oregon, identify both 230Th-excess and 238U-excess components. U-Th isotope compositions cover a wide range, exceeding those previously measured for the Cascade arc. Age-corrected (230Th/232Th) and (238U/232Th) activity ratios range from 1.113 to 1.464 and from 0.878 to 1.572 (44.4 % 230Th-excess to 8.8 % 238U-excess), respectively. The most distinctive aspect of the data set is the contrast in U-Th isotope ratios between low and high Sr (LSr, HSr) components that have been previously identified in products of the 7.7 ka caldera-forming climactic eruption and preclimactic rhyodacite lavas. The LSr component exclusively contains 238U-excess, but the HSr component, as well as more primitive lavas, are marked by 230Th-excess. 230Th-excesses such as those recorded at Mt. Mazama are commonly observed in the Cascades. Melting models suggest that high 230Th-excesses observed in the more primitive lavas evolved through mixing of a mantle melt with a partial melt of a mafic lower crustal composition that contained garnet in the residuum that was produced through dehydration melting of amphibolite that was initially garnet free. Dehydration melting in the lower crust offers a solution to the "hot-slab paradox" of the Cascades, where low volatile contents are predicted due to high slab temperatures, yet higher water contents than expected have been documented in erupted lavas. The 238U-excess observed at Mt. Mazama is rare in Cascade lavas, but occurs in more than half of the samples analyzed in this study. Traditionally, 238U-excess in arc magmas is interpreted to reflect slab fluid fluxing. Indeed, 238U-excess in arcs is common and likely masks 230Th-excess resulting from lower crustal interaction. Isotopic and trace element data, however, suggest a relatively minor role for slab fluid fluxing in the Cascades. We propose that 238U

  1. Recycling, Remobilization, and Eruption of Crystals from the Lassen Volcanic Center

    Science.gov (United States)

    Schrecengost, K.; Cooper, K. M.; Kent, A. J.; Huber, C.; Clynne, M. A.

    2016-12-01

    The Lassen Volcanic Center recently produced two relatively small dacitic eruptions (0.03 km3 -1.4 km3) with a complex mixing history. Preliminary data for the 1915 Lassen Peak (LP) and the 1103±13 ybp Chaos Crags (CC) eruptions indicate complex mixing between a remobilized crystal mush (hornblende, biotite, sodic plagioclase, quartz) and basalt or basaltic andesite. U-series bulk ages represent crystallization of plagioclase at an average age of either a single event or a mixture of different plagioclase populations that crystallized during distinct crystallization events separated in time. We present 238U-230Th disequilibria for the LP light dacite and black dacite along with three stages (upper pyroclastic flow deposit, Dome B, and Dome F) of the CC eruption. Initial 230Th/232Th activity ratios for the LP plagioclase are higher than the LP host liquid and modeled equilibrium zero-age plagioclase towards the CC host liquid composition. The LP plagioclase data are inconsistent with crystallization from the LP host liquid. Therefore, at least a portion of the plagioclase carried by the LP eruptive products are antecrystic originating from an older and/or isotopically distinct host liquid composition. Moreover, LP bulk plagioclase is consistent with crystallization from the CC host liquid, suggesting that both eruptions are sourced from a similar host reservoir (i.e., crystal mush). Hornblende and biotite from the LP eruption have isotopic ratios that are consistent with zero age crystallization from the LP liquid composition, suggesting that they are younger and originate from a different magma than the plagioclase, with mixing between the magmas prior to eruption. However, it is more likely that hornblende, biotite, and plagioclase with varying average crystal ages were remobilized and erupted from a common crystal mush reservoir during the LP and CC eruptions. These data are consistent with zircon 238U-230Th model ages [1] that emphasize the importance of local

  2. Assessment of environmental radioactivity in soil, water and foods consumed in the northeastern state of Sergipe - Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, L.X.; Souza, S.O., E-mail: fiseandro@yahoo.com.br, E-mail: susanasouzalalic@gmail.com [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil). Dept. de Fisica; Cardoso, S.N.M.; Alhanati, C.E., E-mail: sergion@eletronuclear.gov.br, E-mail: alhanat@eletronuclear.gov.br [Eletrobras Termonuclear S.A. (ELETRONUCLEAR), Paraty, RJ (Brazil). Div. de Meio Ambiente e Seguranca do Trabalho; Ciolini, R., E-mail: r.ciolini@ing.unipi.it [University of Pisa (UNIPI), Largo Lazzarino, Pisa (Italy)

    2013-07-01

    Measurements of radioactivity in the environment are of great importance in monitoring and control of radiation levels to which humans are exposed directly or indirectly. Two nuclear power plants are planned in the northeast Brazilian region by the Ministry of Mines and Energy under the National Energy Plan 2030. Even without defining the exact location where these new plants would be built, there is great speculation that new units will be built along the banks of the San Francisco River. This region is extremely poor in studies from the standpoint of determining the radioactivity in the environment, being practically non-existent in the literature data on the state of Sergipe. This study aimed to contribute to analysis of the occurrence of natural and artificial radioactive material in soil, water and food products of the State of Sergipe, focusing primarily on Neopolis Plateau region, which is located the banks of the Rio San Francisco. For this purpose, radionuclides found in all samples collected from soil and cement, fertilizer and food chain products were analyzed by gamma spectrometry, whose activity was measured employing an HPGe detector. The ingestion of contaminated food is a potentially important form of internal exposure. The internal dose due to ingestion depends on the concentration of radionuclides in food and their effective half-life. This study also presents new data for the activity of several natural radionuclides in some aliments produced in the region and the corresponding effective dose due to their intake. Be-7 was detected in organic fertilizers and lemon peel and Th-232 found in samples of soil and cement, both unprecedented results in the literature. The committed effective dose by radionuclides and the total average effective dose calculated for food and the activities of radionuclides measured in all kind of samples were below the Brazilian radioprotection law dose limits. However, it was also detected Cs-137 in some samples, due to

  3. In-situ tracer tests and models developed to understand flow paths in a shear zone at the Grimsel Test Site, Switzerland

    Science.gov (United States)

    Blechschmidt, I.; Martin, A. J.

    2012-12-01

    The Grimsel Test Site (www.grimsel.com) is an international underground research laboratory excavated at a depth of 450m below the surface in the crystalline Aare Massif of southern Switzerland in 1984. It is operated and owned by the National Cooperative for the Disposal of Radioactive Waste of Switzerland (NAGRA) which is the organization responsible for managing and researching the geological disposal of all types of radioactive wastes originating in Switzerland. One experiment, the Colloid Formation and Migration test (CFM*), is an ongoing in-situ migration test started in 2004 to study colloid facilitated transport behavior of radionuclides through a shear zone. The importance of colloid transport in the context of a radioactive waste repository is that it provides a mechanism for potentially enhancing the advective transport of radionuclides. The montmorillonite clays that are planned to be used as an engineered barrier around the radioactive waste in many repository concepts may be a source of such colloids under specific hydraulic and/or chemical boundary conditions. The CFM project includes an integrated programme of field testing, laboratory studies and modelling/interpretation. The field tests are performed in a shear zone where the natural outflow has been controlled by a tunnel packer system and flow is monitored with an array of boreholes drilled for CFM and previous experiments at the site. The flow field is controlled by a low-rate extraction from a surface packer. The controlled low-rate extraction creates a region of low hydraulic gradients and fluid velocity within the shear zone, suitable for study under repository-relevant or other geo-resource relevant conditions. Here we present a summary of the migration tracer tests carried out so far to understand the hydraulic properties and transport characteristics of the shear zone using both stable and radioactive (Na-22, Cs-137, Ba-133, Th-232, Np-237, Am-243, Pu-242) tracers as well as colloids, and

  4. U-series disequilibria in MORB from the Garrett Transform and implications for mantle melting

    Science.gov (United States)

    Tepley, Frank J.; Lundstrom, Craig C.; Sims, Kenneth W. W.; Hékinian, Roger

    2004-06-01

    Here, we report 238U- 230Th- 231Pa- 226Ra disequilibria and 87Sr/ 86Sr measurements in 11 mid-ocean ridge basalt (MORB) glasses from the Garrett Transform (˜13°30'S latitude on the East Pacific Rise [EPR]) whose compositions range from primitive, depleted high-MgO basalts to evolved basalts. U and Th concentrations of samples range between 3 and 75 ppb and between 6 and 220 ppb, respectively, with a corresponding large variation in Th/U (1.5-2.9). ( 230Th)/( 232Th) varies from 1.2 to 1.6 such that ( 230Th)/( 238U) range from ˜15% excess 230Th in a high-Th/U evolved sample to ˜25% excess 238U in a high-MgO sample with low Th/U. Out of 11 samples, 7 have 238U excess, an unusual feature for MORB. All samples have 226Ra excesses, with ( 226Ra)/( 230Th) varying between 1.3 and 3.8 constraining ages since eruption to Siqueiros Transform shows a remarkable correspondence between sample setting, composition and disequilibria systematics. Both settings produce linear trends of ( 230Th)/( 238U) as a function of Th/U, consistent with mixing between two melts derived from different depths in the melting column. The mixing relationships are identical in both locations: The most incompatible rich samples with the highest Th/U and 230Th excess come from the ridge-transform intersection (RTI), whereas the most incompatible element poor basalts with the lowest ( 230Th)/( 238U) and Th/U are erupted along leaky transform faults. Samples with intermediate Th/U and ( 230Th)/( 238U) all come from within intra-transform spreading centers, consistent with the spreading centers acting to homogenize these diverse magmas. The cause of variation in Th/U could reflect either melting processes or different long-lived sources. No clear indication exists within these data.

  5. Thoron Mitigation System based on charcoal bed for applications in thorium fuel cycle facilities (part 2): Development, characterization, and performance evaluation.

    Science.gov (United States)

    Sudeep Kumara, K; Sahoo, B K; Gaware, J J; Sapra, B K; Mayya, Y S; Karunakara, N

    2017-06-01

    Exposure due to thoron ( 220 Rn) gas and its decay products in a thorium fuel cycle facility handling thorium or 232 U/ 233 U mixture compounds is an important issue of radiological concern requiring control and mitigation. Adsorption in a flow-through charcoal bed offers an excellent method of alleviating the release of 220 Rn into occupational and public domain. In this paper, we present the design, development, and characterization of a Thoron Mitigation System (TMS) for industrial application. Systematic experiments were conducted in the TMS for examining the 220 Rn mitigation characteristics with respect to a host of parameters such as flow rate, pressure drop, charcoal grain size, charcoal mass and bed depth, water content, and heat of the carrier gas. An analysis of the experimental data shows that 220 Rn attenuation in a flow through charcoal bed is not exponential with respect to the residence time, L/U a (L: bed depth; U a : superficial velocity), but follows a power law behaviour, which can be attributed to the occurrence of large voids due to wall channeling in a flow through bed. The study demonstrates the regeneration of charcoal adsorption capacity degraded due to moisture adsorption, by hot air blowing technique. It is found that the mitigation factor (MF), which is the ratio of the inlet 220 Rn concentration (C in ) to the outlet 220 Rn concentration (C out ), of more than 10 4 for the TMS is easily achievable during continuous operation (>1000 h) at a flow rate of 40 L min -1 with negligible (<1 cm of water column) pressure drop. The Thoron Mitigation System based on adsorption on charcoal bed offers a compact and effective device to remove 220 Rn from affluent air streams in a space constrained domain. The prototype system has been installed in a thorium fuel cycle facility where it is being evaluated for its long-term performance and overall effectiveness in mitigating 220 Rn levels in the workplace. Copyright © 2017 Elsevier Ltd. All

  6. CHRONOLOGICAL CONSTRAINTS ON FLUID CIRCULATION IN MESOZOIC FORMATIONS OF THE EASTERN PART OF THE PARIS BASIN INFERRED FROM U-Pb DATING OF SECONDARY INFILLING CARBONATES

    Science.gov (United States)

    Pisapia, C.; Deschamps, P.; Hamelin, B.; Buschaert, S.

    2009-12-01

    equilibrium composition, indicating that the precipitation phase was older than 650 ky. U-Pb measurements were performed on a VG sector Thermal Ionization Mass Spectrometer (TIMS) using a 205Pb-236U-233U-229Th spike. Pb contents are generally very low, between 3 and 20 ppb, while U contents are more variable, leading to μ = 238U/204Pb up to ~600. Sub-samples with high μ show radiogenic 206Pb/204Pb ratio, but at this stage isochrons generally show high scatter. These U-Pb data however are consistent with an Eocene-Oligocene period for the late carbonates precipitation phase. We will discuss the different processes that may be responsible for these errorchrons (i.e. heterogeneities in the initial isotopic composition; multi-stage growth) as well as the chronological constraints that can be drawn from these data.

  7. MITEE: A Compact Ultralight Nuclear Thermal Propulsion Engine for Planetary Science Missions

    Science.gov (United States)

    Powell, J.; Maise, G.; Paniagua, J.

    2001-01-01

    A new approach for a near-term compact, ultralight nuclear thermal propulsion engine, termed MITEE (Miniature Reactor Engine) is described. MITEE enables a wide range of new and unique planetary science missions that are not possible with chemical rockets. With U-235 nuclear fuel and hydrogen propellant the baseline MITEE engine achieves a specific impulse of approximately 1000 seconds, a thrust of 28,000 newtons, and a total mass of only 140 kilograms, including reactor, controls, and turbo-pump. Using higher performance nuclear fuels like U-233, engine mass can be reduced to as little as 80 kg. Using MITEE, V additions of 20 km/s for missions to outer planets are possible compared to only 10 km/s for H2/O2 engines. The much greater V with MITEE enables much faster trips to the outer planets, e.g., two years to Jupiter, three years to Saturn, and five years to Pluto, without needing multiple planetary gravity assists. Moreover, MITEE can utilize in-situ resources to further extend mission V. One example of a very attractive, unique mission enabled by MITEE is the exploration of a possible subsurface ocean on Europa and the return of samples to Earth. Using MITEE, a spacecraft would land on Europa after a two-year trip from Earth orbit and deploy a small nuclear heated probe that would melt down through its ice sheet. The probe would then convert to a submersible and travel through the ocean collecting samples. After a few months, the probe would melt its way back up to the MITEE lander, which would have replenished its hydrogen propellant by melting and electrolyzing Europa surface ice. The spacecraft would then return to Earth. Total mission time is only five years, starting from departure from Earth orbit. Other unique missions include Neptune and Pluto orbiter, and even a Pluto sample return. MITEE uses the cermet Tungsten-UO2 fuel developed in the 1960's for the 710 reactor program. The W-UO2 fuel has demonstrated capability to operate in 3000 K hydrogen for

  8. Space and Terrestrial Power System Integration Optimization Code BRMAPS for Gas Turbine Space Power Plants With Nuclear Reactor Heat Sources

    Science.gov (United States)

    Juhasz, Albert J.

    2007-01-01

    In view of the difficult times the US and global economies are experiencing today, funds for the development of advanced fission reactors nuclear power systems for space propulsion and planetary surface applications are currently not available. However, according to the Energy Policy Act of 2005 the U.S. needs to invest in developing fission reactor technology for ground based terrestrial power plants. Such plants would make a significant contribution toward drastic reduction of worldwide greenhouse gas emissions and associated global warming. To accomplish this goal the Next Generation Nuclear Plant Project (NGNP) has been established by DOE under the Generation IV Nuclear Systems Initiative. Idaho National Laboratory (INL) was designated as the lead in the development of VHTR (Very High Temperature Reactor) and HTGR (High Temperature Gas Reactor) technology to be integrated with MMW (multi-megawatt) helium gas turbine driven electric power AC generators. However, the advantages of transmitting power in high voltage DC form over large distances are also explored in the seminar lecture series. As an attractive alternate heat source the Liquid Fluoride Reactor (LFR), pioneered at ORNL (Oak Ridge National Laboratory) in the mid 1960's, would offer much higher energy yields than current nuclear plants by using an inherently safe energy conversion scheme based on the Thorium --> U233 fuel cycle and a fission process with a negative temperature coefficient of reactivity. The power plants are to be sized to meet electric power demand during peak periods and also for providing thermal energy for hydrogen (H2) production during "off peak" periods. This approach will both supply electric power by using environmentally clean nuclear heat which does not generate green house gases, and also provide a clean fuel H2 for the future, when, due to increased global demand and the decline in discovering new deposits, our supply of liquid fossil fuels will have been used up. This is

  9. Monte Carlo analysis of experiments on the reactivity temperature coefficient for UO{sub 2} and MOX light water moderated lattices

    Energy Technology Data Exchange (ETDEWEB)

    Erradi, L.; Chetaine, A. [Faculte des Sciences, Groupe de Physique des Reacteurs, Rabat Maroc (Morocco); Chakir, E.; Kharchaf, A. [Faculte des sciences de Kenitra, Dept. de physique (Morocco); Elbardouni, T. [Faculte des Sciences de Tetouan, Dept. de Physique (Morocco); Elkhoukhi, T. [CNESTEN, Rabat (Morocco)

    2005-07-01

    In a previous work, we have analysed the main French experiments available on the reactivity temperature coefficient (RTC): CREOLE and MISTRAL experiments. In these experiments, the RTC has been measured in both UO{sub 2} and UO{sub 2}-PuO{sub 2} PWR type lattices. Our calculations, using APOLLO2 code with CEA93 library based on JEF2.2 evaluation, have shown that the calculation error in UO{sub 2} lattices is less than 1 pcm/C degrees which is considered as the target accuracy. On the other hand the calculation error in the MOX lattices is more significant in both low and high temperature ranges: an average error of -2 {+-} 0.5 pcm/C degrees is observed in low temperatures and an error of +3 {+-} 2 pcm/C degrees is obtained for temperatures higher than 250 C degrees. In the present work, we analysed additional experimental benchmarks on the RTC of UO{sub 2} and MOX light water moderated lattices. To analyze these benchmarks and with the aim of minimizing uncertainties related to modelling of the experimental set up, we chose the Monte Carlo method which has the advantage of taking into account in the most exact manner the geometry of the experimental configurations. This analysis shows for the UO{sub 2} lattices, a maximum experiment-calculation deviation of about 0,7 pcm/C degrees, which is below the target accuracy for this type of lattices. For the KAMINI experiment, which relates to the measurement of the RTC in a light water moderated lattice using U-233 as fuel our analysis shows that the ENDF/B6 library gives the best result, with an experiment-calculation deviation of the order of -0,16 pcm/C degrees. The analysis of the benchmarks using MOX fuel made it possible to highlight a discrepancy between experiment and calculation on the RTC of about -0.7 pcm/C degrees (for a range of temperatures going from 20 to 248 C degrees) and -1,2 pcm/C degrees (for a range of temperatures going from 20 to 80 C degrees). This result, in particular the tendency which has the

  10. Application of a gamma spectroscopy system to the measurement of neutron cross sections necessary to the development of nuclear energy; Mise au point d'un systeme de spectroscopie pour mesurer des sections efficaces neutroniques applicables a un possible developpement du nucleaire comme source d'energie

    Energy Technology Data Exchange (ETDEWEB)

    Deruelle, O

    2002-09-01

    This work concerns the development of nuclear energy and nuclear waste management in particular. Two parts of this study can be distinguished. In the first part (theoretical), a thorium-plutonium fuel based on MOX and dedicated for PWR was investigated in order to transmute plutonium in a potentially low waste fuel cycle. It was shown that this type of fuel is not regenerative but could be used for a transition to the industrial thorium fuel cycle without building new reactors. Thanks to moderated neutron spectra and high loaded actinide mass in the core, U-233 is quickly created ({approx}300 kg/y) for a loss of about {approx}1200 kg of fissile plutonium. In the second part (experimental), we have developed and built a new reaction chamber to measure neutron cross sections of actinides by alpha-gamma spectroscopy. This experimental device (in principle transportable) was commissioned in the high flux reactor of ILL Grenoble. Neutron flux was measured by gamma spectroscopy of irradiated Al and Co samples and was found to be of the order of 6,0. 10{sup 14} n.cm{sup -2}.s{sup -1} (4%). By the irradiation of 11{mu}g of Am-243 and Pu-242, corresponding capture cross sections were measured in the thermal neutron flux at 50 deg C. These are the results: {sup 243}Am(n,{gamma}) {sup 244fond.}Am = 4,72{+-}1,42b; {sup 243}Am(n,{gamma}) {sup 244total}Am = 74,8{+-}3,25b; {sup 242}Pu (n,{gamma}){sup 243}Pu = 22,7{+-}1,09b. Uncertainties of the measurements are mostly due to the determination of the neutron flux, efficiency of the electronics and ambiguities related to the definition of the area under {alpha}-{gamma} spectra. Although our measured cross sections deviate (by 10-30%) from the corresponding values widely used in evaluated data libraries such as ENDF, JEF and JENDL, in this work we have demonstrated the feasibility and principle of our experimental method. Furthermore, the value for the 243-americium capture cross-section is in very good agreement with the last two

  11. Natural Isotopic Fractionation of 238U/235U in the Water Column of the Black Sea

    Science.gov (United States)

    Romaniello, S. J.; Brennecka, G.; Anbar, A. D.; Colman, A. S.

    2009-12-01

    The natural fractionation of long-lived uranium isotopes (238U, 235U) is being explored as a paleoredox proxy. While uranium behaves conservatively in oxic seawater, it is readily removed to sediments under reducing conditions. Measurements of δ238/235U in black shales and marine sediments deposited under sulfidic conditions suggest that uranium removed in such environments is isotopically heavy. However, this fractionation process has not been directly demonstrated in a present-day marine environment, nor is the specific mechanism of fractionation known. The euxinic water column of the Black Sea provides an ideal laboratory for studying uranium isotope fractionation. Uranium in Black Sea sediments is 0.35-0.84‰ heavy in δ238/235U relative to open ocean seawater (Weyer et al. 2008). We therefore expect that dissolved uranium in the Black Sea water column should be correspondingly light. Furthermore, direct measurements of δ238/235U versus depth could be used in combination with sediment δ238/235U to infer the dominant locations of U removal and constrain specific mechanisms of fractionation. Here we present the first δ238/235U depth profile from the water column of the Black Sea. The measurements were made on a Neptune MC-ICP-MS, using a 236U-233U double spike to correct for instrumental mass bias, following preconcentration and purification with UTEVA resin. With this method, we are able to measure δ238/235U with a 2σ precision of 0.07‰ on 100 ng samples. Our results show that δ238/235U decreases monotonically with depth (Fig. 1). At the surface, δ238/235U values are similar to those in the open ocean. At 2000m, δ238/235U is 0.28‰ lighter than open ocean seawater, while uranium concentrations are depleted by ~44% relative to conservative mixing. As expected, δ238/235U in the water column is always lighter than the underlying sediments, confirming that 238U is preferentially removed to marine sediments under sulfidic conditions. Fig 1. (left) Depth

  12. Tank 40 final sludge batch 9 chemical and fissile radionuclide characterization results

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Kubilius, W. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Pareizs, J. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-06-26

    carbon/total organic carbon (TIC/TOC) analyses. Weighted dilutions of slurry were submitted for IC, TIC/TOC, and total base/free OH-/other base analyses. Activities for U-233, U-235, and Pu-239 were determined from the ICP-MS data for the aqua regia digestions of the SB9 WAPS slurry using the specific activity of each isotope. The Pu-241 value was determined from a Pu-238/-241 method developed by SRNL AD and previously described.v

  13. Radioactive and chemical contamination of the water resources in the former uranium mining and milling sites of Mailuu Suu (Kyrgyzstan).

    Science.gov (United States)

    Corcho Alvarado, J A; Balsiger, B; Röllin, S; Jakob, A; Burger, M

    2014-12-01

    An assessment of the radioactive and chemical contamination of the water resources at the former uranium mines and processing sites of Mailuu-Suu, in Kyrgyzstan, was carried out. A large number of water samples were collected from the drinking water distribution system (DWDS), rivers, shallow aquifers and drainage water from the mine tailings. Radionuclides and trace metal contents in water from the DWDS were low in general, but were extremely high for Fe, Al and Mn. These elements were associated with the particle fractions in the water and strongly correlated with high turbidity levels. Overall, these results suggest that water from the DWDS does not represent a serious radiological hazard to the Mailuu Suu population. However, due to the high turbidities and contents of some elements, this water is not good quality drinking water. Water from artesian and dug wells were characterized by elevated levels of U (up to 10 μg/L) and some trace elements (e.g. As, Se, Cr, V and F) and anions (e.g. Cl(-), NO3(-), SO4(2-)). In two artesian wells, the WHO guideline value of 10 μg/L for As in water was exceeded. As the artesian wells are used as a source of drinking water by a large number of households, special care should be taken in order to stay within the WHO recommended guidelines. Drainage water from the mine tailings was as expected highly contaminated with many chemicals (e.g. As) and radioactive contaminants (e.g. U). The concentrations of U were more than 200 times the WHO guideline value of 30 μg/L for U in drinking water. A large variation in (234)U/(238)U isotopic ratios in water was observed, with values near equilibrium at the mine tailings and far from equilibrium outside this area (reaching ratios of 2.3 in the artesian well). This result highlights the potential use of this ratio as an indicator of the origin of U contamination in Mailuu Suu. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. El radón: ¿riesgo para la salud?

    Directory of Open Access Journals (Sweden)

    Juan Miguel Barros Dios

    2011-12-01

    Full Text Available El radón (Rn222 es un gas noble radiactivo que procede directamente del radio (Ra226 cuando este emite una partícula alfa (dos protones y dos neutrones o núcleo de helio, y que a su vez se transforma en otro elemento radiactivo (Po218 al desprenderse de otra partícula alfa. Desde hace varias décadas se conoce su efecto como factor de riesgo del cáncer primario pulmonar, primero en mineros del uranio y posteriormente en la población general expuesta al radón residencial en hogares construidos sobre suelos de rocas ricas en uranio (U238, elemento inicial de la cadena de degradación radiactiva de la que procede el radón. Áreas geológicamente constituidas por granitos o pizarras, como son las de gran parte de Galicia y todo el noroeste y oeste de la península ibérica, han sido catalogadas como de alto riesgo de exhalación de radón al interior de edificios y domicilios. En numerosos países de América y Europa existen desde hace varios lustros, políticas de prevención del cáncer pulmonar en aquellas zonas de riesgo basadas en programas de reducción de radón en los domicilios y edificios públicos. Desde finales de los años 80, la radiación alfa procedente del radón y sus descen- dientes de vida media corta han sido clasificados como agentes cancerígenos por la Internacional Agency of Research on Cancer (Lyon, 1988 y el Nacional Research Council (BEIR IV, 1988, constituyendo la segunda causa de cáncer pulmonar después del tabaco, y responsable del 10 al 15 % de todas las muertes por esa neoplasia. Estudios realizados en Galicia confirman esta evidencia, con riesgos de 2 a 3 en expuestos a concentraciones del gas en domicilios y la responsabilidad directa del 9% de todos los casos de cáncer pulmonar del área estudiada y una interacción radón/tabaco que multiplica por 45 el riesgo.

  15. Radioactivity monitoring of the P.P

    Energy Technology Data Exchange (ETDEWEB)

    Joksic, J.; Todorovic, D.; Radenkovic, M. [VINCA Institute of Nuclear Sciences, Radiation and Enviro nmental Protecti on Lab., Belgrade (Serbia and Montenegro)

    2006-07-01

    The radioactivity monitoring in the 'Nikola Tesla' thermo-electric power plant environment comprised the analysis of soil, waters, flying ash, slag and plants. Soil, plant and water samples were taken in the environment of the 'Tent A', 'Tent B', 'Kolubara' and 'Morava' power plants during the two years period 2003-2004 and analyzed b y standard radiometric methods. Naturally occurring radionuclides 226 Ra, 232 Th, 40 K, 235 U, 238 U, 210 Pb are determined by gamma spectrometry using H.P. Ge detector, relative efficiency of 23% and energy resolution of 1.8 keV (1332.5 keV). Ceied reference materials: soil matrix with 55 Na, 57 Co, 60 Co, 89 Y, 133 Ba and 137 Cs (MIX-OMHSZ, National Office of Measures) and grass with 134 Cs, 137 Cs, 40 K and 90 Sr (IAEA-373) were used for calibration. The gross alpha and gross beta activity measurements are carried out using low-level background alpha-beta proportional gas counter. Radiochemical analyzes of soil samples have shown the naturally occurring radionuclides: 226 Ra 35-60 Bq/kg, 232 Th 35-49 Bq/kg, 40 K 513-711 Bq/kg, 210 Pb 14-69 Bq/kg, 238 U 25-80 Bq/kg and 235 U 1.1-4.5 Bq/kg. The 137 Cs was found in concentration 10-57 Bq/kg. Radiochemical analyzes of plant samples have shown the naturally occurring radionuclides: 226 Ra 0.7-6.1 Bq/kg, 232 Th 1-4.8 Bq/kg, 40 K 392-1132 Bq/kg, 210 Pb 5.6-97 Bq/kg, 238 U 2.3-7.4 Bq/kg and 235 U 0.2-0.7 Bq/kg. The 137 Cs was found in concentration 0.13-2.8 Bq/kg. The water samples were within the range of recommended values for drinking waters in Serbia and Montenegro. Total alpha activity was below the lowest limit of detection and total beta activities were up to 0.35 Bq/l. The results of measured radionuclides in soil, plant and water samples do not show any significant radioactive environmental pollution. (authors)

  16. Radiological risk from consuming fish and wildlife to Native Americans on the Hanford Site (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Delistraty, Damon, E-mail: DDEL461@ecy.wa.gov [Washington State Department of Ecology, N. 4601 Monroe, Spokane, WA 99205-1295 (United States); Verst, Scott Van [Washington State Department of Health, Olympia, WA (United States); Rochette, Elizabeth A. [Washington State Department of Ecology, Richland, WA (United States)

    2010-02-15

    Historical operations at the Hanford Site (Washington State, USA) have released a wide array of non-radionuclide and radionuclide contaminants into the environment. As a result of stakeholder concerns, Native American exposure scenarios have been integrated into Hanford risk assessments. Because its contribution to radiological risk to Native Americans is culturally and geographically specific but quantitatively uncertain, a fish and wildlife ingestion pathway was examined in this study. Adult consumption rates were derived from 20 Native American scenarios (based on 12 studies) at Hanford, and tissue concentrations of key radionuclides in fish, game birds, and game mammals were compiled from the Hanford Environmental Information System (HEIS) database for a recent time interval (1995-2007) during the post-operational period. It was assumed that skeletal muscle comprised 90% of intake, while other tissues accounted for the remainder. Acknowledging data gaps, median concentrations of eight radionuclides (i.e., Co-60, Cs-137, Sr-90, Tc-99, U-234, U-238, Pu-238, and Pu-239/240) in skeletal muscle and other tissues were below 0.01 and 1 pCi/g wet wt, respectively. These radionuclide concentrations were not significantly different (Bonferroni P>0.05) on and off the Hanford Site. Despite no observed difference between onsite and offsite tissue concentrations, radiation dose and risk were calculated for the fish and wildlife ingestion pathway using onsite data. With median consumption rates and radionuclide tissue concentrations, skeletal muscle provided 42% of the dose, while other tissues (primarily bone and carcass) accounted for 58%. In terms of biota, fish ingestion was the largest contributor to dose (64%). Among radionuclides, Sr-90 was dominant, accounting for 47% of the dose. At median intake and radionuclide levels, estimated annual dose (0.36 mrem/yr) was below a dose limit of 15 mrem/yr recommended by the United States Environmental Protection Agency (USEPA

  17. A Record of Uranium-Series Transport in Fractured, Unsaturated Tuff at Nopal I, Sierra Peña Blanca, Chihuahua, Mexico

    Science.gov (United States)

    Denton, J.; Goldstein, S. J.; Paviet, P.; Nunn, A. J.; Amato, R. S.; Hinrichs, K. A.

    2015-12-01

    In this study we utilize U-series disequilibria measurements to investigate mineral fluid interactions and the role fractures play in the geochemical evolution of an analogue for a high level nuclear waste repository, the Nopal I uranium ore deposit. Samples of fracture-fill materials have been collected from a vertical drill core and surface fractures. High uranium concentrations in these materials (12-7700 ppm) indicate U mobility and transport from the deposit in the past. U concentrations generally decrease with horizontal distance away from the ore deposit but show no trend with depth. Isotopic activity ratios indicate a complicated geochemical evolution in terms of the timing and extent of actinide mobility, possibly due to changing environmental (redox) conditions over the history of the deposit. 234U/238U activity ratios are generally distinct from secular equilibrium and indicate some degree of open system U behavior during the past 1.2 Ma. However, calculated closed system 238U-234U-230Th model ages are generally >313 ka and >183 ka for the surface fracture and drill core samples respectively, suggesting closed system behavior for U and Th over this most recent time period. Whole rock isochrons drawn for the drill core samples show that at two of three depths fractures have remained closed with respect to U and Th mobility for >200 ka. However, open system behavior for U in the last 350 ka is suggested at 67 m depth. 231Pa/235U activity ratios within error of unity suggest closed system behavior for U and Pa for at least the past 185 ka. 226Ra/230Th activity ratios are typically <1 (0.7-1.2), suggesting recent (<8 ka) radium loss and mobility due to ongoing fluid flow in the fractures. Overall, the mainly closed system behavior of U-Th-Pa over the past ~200 ka provides one indicator of the geochemical immobility of these actinides over long time-scales for potential nuclear waste repositories sited in fractured, unsaturated tuff.

  18. Deposition of vaporized species onto glassy fallout from a near-surface nuclear test

    Science.gov (United States)

    Weisz, David G.; Jacobsen, Benjamin; Marks, Naomi E.; Knight, Kim B.; Isselhardt, Brett H.; Matzel, Jennifer E.; Weber, Peter K.; Prussin, Stan G.; Hutcheon, Ian D.

    2017-03-01

    In a near-surface nuclear explosion where the resultant fireball can interact with the surface, vaporized materials from the nuclear device can be incorporated into molten soil and other carrier materials from that surface. This mixed material becomes a source of glassy fallout upon quenching and is locally deposited. Fallout formation models have been proposed; however, the specific mechanisms and physical conditions by which soil and other carrier materials interact in the fireball, as well as the subsequent incorporation of device materials with carrier materials, are not well constrained. We observe a surface deposition layer preserved at interfaces where two aerodynamic fallout glasses agglomerated and fused, and characterized 11 such boundaries using spatial analyses to better understand the vaporization and condensation behavior of species in the fireball. Using nanoscale secondary ion mass spectrometry (NanoSIMS), we identify higher enrichments of uranium from the device (235U/238U ratio >7.5) in 8 of the interface layers. Major element analysis of the interfaces reveals the deposition layer to be enriched in Fe, Ca, Mg, Mn, and Na-bearing species and depleted in Ti and Al-bearing species. Most notably, the Fe and Ca-bearing species are enriched approximately 50% at the interface layer relative to the average concentrations measured within the fallout glasses, while Ti and Al-bearing species are depleted by approximately 20%. SiO2 is found to be relatively invariable across the samples and interfaces (∼3% standard deviation). The notable depletion of Al, a refractory oxide abundant in the soil, together with the enrichment of 235U and Fe, suggests an anthropogenic source of the enriched species or an unexpected vaporization/condensation behavior. The presence of both refractory (e.g., Ca and U) and volatile (e.g., Na) species approximately co-located in most of the observed layers (within 1.5 μm) suggests a continuous condensation process may also be

  19. Terrace Geochemistry at the Shiprock, New Mexico, Disposal Site - WM2017-17232 Initial Phase

    Energy Technology Data Exchange (ETDEWEB)

    Kautsky, Mark [USDOE Office of Legacy Management, Washington, DC (United States); Ranalli, Tony [Navarro Research and Engineering, Oak Ridge, TN (United States); Dander, David [Navarro Research and Engineering, Oak Ridge, TN (United States); Miller, David [Navarro Research and Engineering, Oak Ridge, TN (United States)

    2017-03-08

    The objective of this investigation was to identify and differentiate potential non- mill-related water inputs to a shallow terrace groundwater system through the use of aqueous chemical and isotopic tracers at a former uranium- and vanadium-ore processing facility. Terrace groundwater in the vicinity of the Shiprock, New Mexico, site is hypothesized to be largely anthropogenic because natural rates of recharge in the terrace are likely insufficient to sustain a continuous water table in the terrace alluvial system, as observed in several analogue terrace locations east of the site and in response to post-mill dewatering efforts across the site. The terrace is composed of alluvial sand and gravel and weathered and unweathered Mancos Shale. Terrace groundwater exists and flows in the alluvium and to a much less extent in the Mancos Shale. Historical data established that in both the terrace and floodplain below the terrace, mill-derived uranium and sulfate is found primarily in the alluvium and the upper portion of the weathered Mancos Shale. Groundwater extraction is being conducted in the vicinity of former mill operations and in washes and seeps to dewater the formation and remove contamination, thus eliminating these exposure pathways and minimizing movement to the floodplain. However, past and present contribution of non-mill anthropogenic water sources may be hindering the dewatering effort, resulting in reduced remedy effectiveness. Groundwater source signatures can be determined based on chemical and isotopic ratios and are used to help identify and delineate both mill and non-mill water contributions. Aqueous chemical and isotopic tracers, such as 234U/238U activity ratios and uranium concentrations, δ34S sulfate and sulfate concentrations, tritium concentrations, and δ2Hwater and δ18O water are being used in this Phase I study. The aqueous chemical and isotopic analysis has identified areas on the terrace where groundwater is derived from mill

  20. Nuclear Data Sheets for A = 168

    Science.gov (United States)

    Baglin, Coral M.

    2010-07-01

    Nuclear structure data pertaining to all nuclei with mass A=168 (Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt) have been evaluated and incorporated into the ENSDF data file. This evaluation supersedes the previous publication (V.S. Shirley, Nuclear Data Sheets 71, 261 (1994) (literature cutoff date July 1993)) and subsequent ENSDF file revisions for Tb and Dy (C. Baglin, literature cutoff date of 15 June 1999) and Hf (B. Singh, literature cutoff date of 30 April 2001), and includes literature available by 15 June 2010. Since the above evaluations, the first excited states in 168Pt have been identified (1998Ki20, 2009Go16) and α decay from 172Hg has been observed (2009Sa27, 2004Ke06, 1999Se14). New levels in 168Dy have been excited using the 170Er( 82Se, 84Kr γ) reaction (2010So03). (HI,xn γ) studies have significantly expanded our knowledge of level structure in 168Lu (1999Ka17, 2002Ha33), 168Ta (2008QiZZ), 168Yb (1995Fi01), 168Tm (2007CaZW), 168Hf (2009Ya21), 168Os (2001Jo11, 2009Od02) and, for 168Tm, important information has come also from (d,2n γ) and ( α,n γ) reactions (1995Si20). Revised decay schemes are available following new studies of 168Hf ɛ decay (6.7 min) (1997Ba26), 168Lu ɛ decay (1999Ba65), 168Ta ɛ decay (2007Mc08) and 172Au α decay (2009Ha42). Significant new information for 168Er is available from (p,t) (2006Bu09), (d,p) and (t,d) (1996Ma50), ( γ, γ') (1996Ma18), (136Xe, X γ) (2010Dr02), ( 238U, 238Uγ) (2003Wu07) and (n, nγ) (1998Be20, 1998Be62) reactions, and the availability of γγ coin data (1994Ju02, 1996Gi09) for the (n, γ) E=thermal reaction has resulted in some significant level scheme revisions.

  1. Americium, plutonium and uranium contamination and speciation in well waters, streams and atomic lakes in the Sarzhal region of the Semipalatinsk Nuclear Test Site, Kazakhstan.

    Science.gov (United States)

    León Vintró, L; Mitchell, P I; Omarova, A; Burkitbayev, M; Jiménez Nápoles, H; Priest, N D

    2009-04-01

    New data are reported on the concentrations, isotopic composition and speciation of americium, plutonium and uranium in surface and ground waters in the Sarzhal region of the Semipalatinsk Test Site, and an adjacent area including the settlement of Sarzhal. The data relate to filtered water and suspended particulate from (a) streams originating in the Degelen Mountains, (b) the Tel'kem 1 and Tel'kem 2 atomic craters, and (c) wells on farms located within the study area and at Sarzhal. The measurements show that (241)Am, (239,240)Pu and (238)U concentrations in well waters within the study area are in the range 0.04-87mBq dm(-3), 0.7-99mBq dm(-3), and 74-213mBq dm(-3), respectively, and for (241)Am and (239,240)Pu are elevated above the levels expected solely on the basis of global fallout. Concentrations in streams sourced in the Degelen Mountains are similar, while concentrations in the two water-filled atomic craters are somewhat higher. Suspended particulate concentrations in well waters vary considerably, though median values are very low, at 0.01mBq dm(-3), 0.08mBq dm(-3) and 0.32mBq dm(-3) for (241)Am, (239,240)Pu and (238)U, respectively. The (235)U/(238)U isotopic ratio in almost all well and stream waters is slightly elevated above the 'best estimate' value for natural uranium worldwide, suggesting that some of the uranium in these waters is of test-site provenance. Redox analysis shows that on average most of the plutonium present in the microfiltered fraction of these waters is in a chemically reduced form (mean 69%; 95% confidence interval 53-85%). In the case of the atomic craters, the proportion is even higher. As expected, all of the americium present appears to be in a reduced form. Calculations suggest that annual committed effective doses to individual adults arising from the daily ingestion of these well waters are in the range 11-42microSv (mean 21microSv). Presently, the ground water feeding these wells would not appear to be contaminated with

  2. Transuranium radionuclide pollution in the waters of the La Maddalena National Marine Park

    Energy Technology Data Exchange (ETDEWEB)

    Aumento, F. [Marine Environmental Sciences, La Tuscia University, Largo dell' Universita, 01100 Viterbo (Italy)]. E-mail: faumento@tiscali.it; Le Donne, K. [Marine Environmental Sciences, La Tuscia University, Largo dell' Universita, 01100 Viterbo (Italy); Eroe, K. [Marine Environmental Sciences, La Tuscia University, Largo dell' Universita, 01100 Viterbo (Italy)

    2005-07-01

    Following the grounding and subsequent explosion, in October 2003, of a nuclear submarine in the waters of the La Maddalena National Marine Park, fears arose of possible radioactive leakages. However, isotopic analyses on algae showed that the gamma-ray emitting artificial radionuclides that one might expect to leak from a damaged nuclear reactor (such as U-235, I-131, Cs-137) were absent, and that U-238/U-234 activities were in equilibrium with values typical of sea water; this excluded any direct anthropogenic contamination as a result of the accident. We used alpha autoradiographic techniques to detect possible traces of transuranium radionuclides; 160 samples of algae, granites, sea urchins, gastropods, limpets, cuttlefish and jellyfish were collected from the area, as well as from other Mediterranean coastlines and the Baltic Sea. All samples were autoradiographed, and selected samples further analysed by alpha spectrometry. There were no alpha track concentrations above background levels in our control Mediterranean specimens. In the samples from the La Maddalena and Baltic areas two different track distributions were observed:-those homogeneously distributed over the surfaces examined; -groups (10 to over 500) of radially distributed alpha tracks (forming 'star' bursts, or 'hot spots') emanating from point sources. By comparing radionuclide activities measured by alpha spectroscopy with alpha track densities, we extrapolated Pu activities for all samples. About 74% of algae had Pu activities of less than 1Bq/kg and 0.25Bq/kg, 16% had accumulated Pu to levels between 1 and 2Bq/kg, and a very few specimens had concentrations between 2 and 6Bq/kg. Plots showed that alpha tracks and stars concentrate around the northern and eastern margins of the Rada (Basin) di Santo Stefano, sites facing the nuclear submarine base on the eastern shore of the island of Santo Stefano. What is the source of these nuclides: last century's atmospheric

  3. U isotopes distribution in the Lower Rhone River and its implication on radionuclides disequilibrium within the decay series.

    Science.gov (United States)

    Zebracki, Mathilde; Cagnat, Xavier; Gairoard, Stéphanie; Cariou, Nicolas; Eyrolle-Boyer, Frédérique; Boulet, Béatrice; Antonelli, Christelle

    2017-11-01

    The large rivers are main pathways for the delivery of suspended sediments into coastal environments, affecting the biogeochemical fluxes and the ecosystem functioning. The radionuclides from 238U and 232Th-series can be used to understand the dynamic processes affecting both catchment soil erosion and sediment delivery to oceans. Based on annual water discharge the Rhone River represents the largest river of the Mediterranean Sea. The Rhone valley also represents the largest concentration in nuclear power plants in Europe. A radioactive disequilibrium between particulate 226Ra(p) and 238U(p) was observed in the suspended sediment discharged by the Lower Rhone River (Eyrolle et al. 2012), and a fraction of particulate 234Th was shown to derive from dissolved 238U(d) (Zebracki et al. 2013). This extensive study has investigated the dissolved U isotopes distribution in the Lower Rhone River and its implication on particulate radionuclides disequilibrium within the decay series. The suspended sediment and filtered river waters were collected at low and high water discharges. During the 4-months of the study, two flood events generated by the Rhone southern tributaries were monitored. In river waters, the total U(d) concentration and U isotopes distribution were obtained through Q-ICP-MS measurements. The Lower Rhone River has displayed non-conservative U-behavior, and the variations in U(d) concentration between southern tributaries were related to the differences in bedrock lithology. The artificially occurring 236U was detected in the Rhone River at low water discharges, and was attributed to the liquid releases from nuclear industries located along the river. The (235U/238U)(d) activity ratio (=AR) in river waters was representative of the 235U natural abundance on Earth. The (226Ra/238U)(p) AR in suspended sediment has indicated a radioactive disequilibrium (average 1.3 ± 0.1). The excess of 234Th in suspended sediment =(234Thxs(p)) was apparent solely at

  4. A Combined Radio- and Stable-Isotopic Study of a California Coastal Aquifer System

    Directory of Open Access Journals (Sweden)

    Michael Land

    2013-04-01

    Full Text Available Stable and radioactive tracers were utilized in concert to characterize geochemical processes in a complex coastal groundwater system and to provide constraints on the kinetics of rock/water interactions. Groundwater samples from wells within the Dominguez Gap region of Los Angeles County, California were analyzed for a suite of major cations (Na+, K+, Mg2+, Ca2+ and anions (Cl−, SO42−, silica, alkalinity, select trace elements (Ba, B, Sr, dissolved oxygen, stable isotopes of hydrogen (δD, oxygen (δ18O, dissolved inorganic carbon (δ13CDIC, and radioactive isotopes (3H, 222Rn and 223,224,226,228Ra. In the study area, groundwater may consist of a complex mixture of native groundwater, intruded seawater, non-native injected water, and oil-field brine water. In some wells, Cl− concentrations attained seawater-like values and in conjunction with isotopically heavier δ18O values, these tracers provide information on the extent of seawater intrusion and/or mixing with oil-field brines. Groundwater 3H above 1 tritium unit (TU was observed only in a few select wells close to the Dominguez Gap area and most other well groundwater was aged pre-1952