WorldWideScience

Sample records for radiators characteristics 238u

  1. A comparison on determining activities of 238U and 232Th based on transfer samples and some associations of ideas for some investigation passed of environment radiation

    International Nuclear Information System (INIS)

    Su Qiong; Cheng Jianping; Diao Lijun; Li Guiqun

    2006-01-01

    A comparison on determining activities of 238 U and 232 Th based on transfer samples is reported in the paper. Especially, disturbance of X-ray from out-sources i.e. non-nucleus-self are studied and more detailed. And other factors that influence this time comparison result are discussed too in the work. In the paper it is pointed out definitely that the characteristic peaks that are disturbed by characteristic X-rays from out-sources ought to be not adopted to determine activities of the samples. In final some associations of ideas for some investigation passed of environment radiation are also described. (authors)

  2. A comparison on determining activities of 238U and 232Th based on transfer samples and some associations of ideas for some investigation passed of environment radiation

    International Nuclear Information System (INIS)

    Su Qiong; Cheng Jianping; Diao Lijun; Li Guiqun

    2007-01-01

    A comparison on determining activities of 238 U and 232 Th based on transfer samples is reported in the paper. Especially, disturbance of X-ray from out-sources i.e. non-nucleus-self are studied and more detailed. And other factors that influence this time comparison result are discussed too in the work. In the paper it is pointed out definitely that the characteristic peaks that are disturbed by characteristic X-rays from out-sources ought to be not adopted to determine activities of the samples. In final some associations of ideas for some investigation passed of environment radiation are also described. (authors)

  3. parity assignment of the pronounced structure in the radiative capture of neutrons by 238U below 100 keV

    International Nuclear Information System (INIS)

    Moore, M.S.; Corvi, F.; Mewissen, L.; Poortmans, F.

    1981-01-01

    Some years ago, Perez and de Saussure reported evidence for intermediate structure in the radiative capture cross sections of 238 U. More recently, these and additional data, obtained by a different experimental technique but which showed the same non-statistical behavior, were analyzed by Perez et al. Under the assumption that the structure could be attributed to doorway states in the p/sup 3/2/ neutron channel. The results of an experimental determination of the parity of the structure, using neutron capture-gamma ray spectroscopy are reported. Much of the structure below 50 keV appears to be due to s-wave interactions. The magnitude of the fluctuations is much larger than can be calculated with the usual unresolved - resonance treatment unless the average neutron and radiative-capture widths are correlated. It is shown that such an apparent correlation can arise as a result of multiple-scattering enhancement of radiative capture in the samples used, and it is concluded that the evidence for intermediate structure in the capture of neutrons by 238 U is not yet firmly established

  4. The transport characteristics of {sup 238}U, {sup 232}Th, {sup 226}Ra, and {sup 40}K in the production cycle of phosphate rock

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yoon Hee; Lim, Jong Myoung; Ji, Young Yong; Chung, Kun Ho; Kang, Mun Ja [Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-03-15

    Phosphate rock and its by-product are widely used in various industries to produce phosphoric acid, gypsum, gypsum board, and fertilizer. Owing to its high level of natural radioactive nuclides (e.g., 238U and 226Ra), the radiological safety of workers who work with phosphate rock should be systematically managed. In this study, 238U, 232Th, 226Ra, and 40K levels were measured to analyze the transport characteristics of these radionuclides in the production cycle of phosphate rock. Energy dispersive X-ray fluorescence and gamma spectrometry were used to determine the activity of 238U, 232Th, 226Ra, and 40K. To evaluate the extent of secular disequilibrium, the analytical results were compared using statistical methods. Finally, the distribution of radioactivity across different stages of the phosphate rock production cycle was evaluated. The concentration ratios of 226Ra and 238U in phosphate rock were close to 1.0, while those found in gypsum and fertilizer were extremely different, reflecting disequilibrium after the chemical reaction process. The nuclide with the highest activity level in the production cycle of phosphate rock was 40K, and the median 40K activity was 8.972 Bq·g−1 and 1.496 Bq·g−1, respectively. For the 238U series, the activity of 238U and 226Ra was greatest in phosphate rock, and the distribution of activity values clearly showed the transport characteristics of the radionuclides, both for the byproducts of the decay sequences and for their final products. Although the activity of 40K in k-related fertilizer was relatively high, it made a relatively low contribution to the total radiological effect. However, the activity levels of 226Ra and 238U in phosphate rock were found to be relatively high, near the upper end of the acceptable limits. Therefore, it is necessary to systematically manage the radiological safety of workers engaged in phosphate rock processing.

  5. Characteristics of latent damage trails due to high energy 208Pb and 238U ions in CR-39 and muscovite mica

    International Nuclear Information System (INIS)

    Chohan, A.S.; Akhtar, S.M.

    1988-01-01

    Experiments have been performed to study the characteristics of latent damage trails produced by (a) 17.14 MeV/nucleon- 208 Pb ions in mica and CR-39 track detectors and (b) 13.7 MeV/nucleon- 238 U in CR-39 track detectors. The parameters studied include (a) V t , average etching velocity along the track, (b) thermal stability of the latent damage trails, (c) the total etchable ranges, and (d) V g the general etching velocity of CR-39 track detectors previously annealed at different temperatures. It has been observed that the latent damage trails in CR-39 are greatly affected at temperatures around 200 0 C in CR-39 track detectors. The general etching velocity of a CR-39 detector has been found to increase with increasing annealing temperatures. (author)

  6. The transport characteristics of "2"3"8U, "2"3"2Th, "2"2"6Ra, and "4"0K in the production cycle of phosphate rock

    International Nuclear Information System (INIS)

    Jung, Yoon Hee; Lim, Jong Myoung; Ji, Young Yong; Chung, Kun Ho; Kang, Mun Ja

    2017-01-01

    Phosphate rock and its by-product are widely used in various industries to produce phosphoric acid, gypsum, gypsum board, and fertilizer. Owing to its high level of natural radioactive nuclides (e.g., 238U and 226Ra), the radiological safety of workers who work with phosphate rock should be systematically managed. In this study, 238U, 232Th, 226Ra, and 40K levels were measured to analyze the transport characteristics of these radionuclides in the production cycle of phosphate rock. Energy dispersive X-ray fluorescence and gamma spectrometry were used to determine the activity of 238U, 232Th, 226Ra, and 40K. To evaluate the extent of secular disequilibrium, the analytical results were compared using statistical methods. Finally, the distribution of radioactivity across different stages of the phosphate rock production cycle was evaluated. The concentration ratios of 226Ra and 238U in phosphate rock were close to 1.0, while those found in gypsum and fertilizer were extremely different, reflecting disequilibrium after the chemical reaction process. The nuclide with the highest activity level in the production cycle of phosphate rock was 40K, and the median 40K activity was 8.972 Bq·g−1 and 1.496 Bq·g−1, respectively. For the 238U series, the activity of 238U and 226Ra was greatest in phosphate rock, and the distribution of activity values clearly showed the transport characteristics of the radionuclides, both for the byproducts of the decay sequences and for their final products. Although the activity of 40K in k-related fertilizer was relatively high, it made a relatively low contribution to the total radiological effect. However, the activity levels of 226Ra and 238U in phosphate rock were found to be relatively high, near the upper end of the acceptable limits. Therefore, it is necessary to systematically manage the radiological safety of workers engaged in phosphate rock processing

  7. Measurement of activity concentrations of {sup 40}K, 2{sup 32T}h and {sup 238}U in TSP aerosols and the associated inhalation annual effective radiation dose to the public in Gosan site, Jeju

    Energy Technology Data Exchange (ETDEWEB)

    Han, Chung Hun; Park, Youn Hyun; Park, Jae Woo [Jeju National University, Jeju (Korea, Republic of)

    2016-10-15

    Gamma radiation emitted from naturally occurring radioisotopes, such as 40K and the radionuclides from the {sup 232}Th and {sup 238}U series and their decay products, which exist at trace levels in all ground formations, represents the main external source of irradiation to the human body. The objective of the current study is to determine the activity concentrations of 40K, {sup 232}Th and {sup 238}U in airborne TSP and the associated internal radiation dose to the public due to inhalation in Gosan site, Jeju Island, Korea. The atmospheric total suspended particulates (TSP) aerosols were collected at Gosan site of Jeju Island, which is one of the background sites of Korea, during January to April 2013. This study analyzed using ICP-DRC-MS the concentrations of potassium, uranium and thorium, and evaluated the annual effective dose by breathing from the results. The correlations between the studied natural isotopes is a good positive correlation between {sup 232}Th and {sup 238}U, supporting the conclusion that they originated from the same source, mostly the crust. The backward trajectory analysis has confirmed that the 40K, {sup 238}U and {sup 232}Th are delivered as the air masses have moved from the China continent. The inhalation annual effective radiation dose (default mode F) to the public due to natural isotopes of the airborne TSP was in the range 16.195 - 77.051 nSv/y, depending on the age group. Jeju Island with less pollution source and low population density is also one of the best places as a background area in Asia.

  8. Characterization of bauxite residue (red mud) for 235U, 238U, 232Th and 40K using neutron activation analysis and the radiation dose levels as modeled by MCNP.

    Science.gov (United States)

    Landsberger, S; Sharp, A; Wang, S; Pontikes, Y; Tkaczyk, A H

    2017-07-01

    This study employs thermal and epithermal neutron activation analysis (NAA) to quantitatively and specifically determine absorption dose rates to various body parts from uranium, thorium and potassium. Specifically, a case study of bauxite residue (red mud) from an industrial facility was used to demonstrate the feasibility of the NAA approach for radiological safety assessment, using small sample sizes to ascertain the activities of 235 U, 238 U, 232 Th and 40 K. This proof-of-concept was shown to produce reliable results and a similar approach could be used for quantitative assessment of other samples with possible radiological significance. 238 U and 232 Th were determined by epithermal and thermal neutron activation analysis, respectively. 235 U was determined based on the known isotopic ratio of 238 U/ 235 U. 40 K was also determined using epithermal neutron activation analysis to measure total potassium content and then subtracting its isotopic contribution. Furthermore, the work demonstrates the application of Monte Carlo Neutral-Particle (MCNP) simulations to estimate the radiation dose from large quantities of red mud, to assure the safety of humans and the surrounding environment. Phantoms were employed to observe the dose distribution throughout the human body demonstrating radiation effects on each individual organ. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. A remarkable systemic error in calibration methods of γ spectrometer used for determining activity of 238U

    International Nuclear Information System (INIS)

    Su Qiong; Cheng Jianping; Diao Lijun; Li Guiqun

    2006-01-01

    A remarkable systemic error which was unknown in past long time has been indicated. The error appears in the calibration methods of determining activity of 238 U is used with γ-spectrometer with high resolution. When the γ-ray of 92.6 keV as the characteristic radiation from 238 U is used to determine the activity of 238 U in natural environment samples, the disturbing radiation produced by external excitation (or called outer sourcing X-ray radiation) is the main problem. Because the X-ray intensity is changed with many indefinite factors, it is advised that the calibration methods should be put away. As the influence of the systemic errors has been left in some past research papers, the authors suggest that the data from those papers should be cited carefully and if possible the data ought to be re-determined. (authors)

  10. Quasifree electrofission of 238U

    International Nuclear Information System (INIS)

    Likhachev, V.P.; Deppman, A.; Hussein, M.S.; Mesa, J.; Arruda-Neto, J.D.T.; Carlson, B.V.; Nesterenko, V.O.; Garcia, F.; Rodriguez, O.

    2002-01-01

    We present the result of a theoretical study of the quasifree electrofission of 238 U. The exclusive differential cross sections for the quasifree scattering reaction stage have been calculated in plane wave impulse approximation, using a macroscopic-microscopic approach for the description of the proton bound states. The nuclear shape was parametrized in terms of Cassinian ovoids. The equilibrium deformation parameters have been calculated by minimizing the total nuclear energy. In the calculation the axially deformed Woods-Saxon single-particle potential was used. The obtained single-particle momentum distributions were averaged over the nuclear symmetry axis direction. The occupation numbers were calculated in the BCS approach. The fissility for the single-hole excited states of the residual nucleus 237 Pa was calculated on the statistical theory grounds, both without taking into account the preequilibrium emission of the particle and with preequilibrium emission in the framework of the exciton model

  11. Internal radiation due to bioaccumulated natural radionuclides ({sup 238}U and {sup 226}Ra) in some wild plants sampled from Singhbhum Thrust Belt

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V K [Co-operative College, Jamshedpur (India). Botany Dept.; Geeta, [Jamshedpur Women` s College, Jamshedpur (India). Botany Dept.

    1995-01-01

    Estimation of radioactivity (Bq/Kg dry Wt.) due to bioaccumulated {sup 238}U,{sup 226}Ra was carried out in six species of native plants growing in the non-occupational settings of Singhbhum Thrust Belt (STB). Due to medicinal and other economic values, these plants are used by the local people in their day to day life. Among the six species, Echinops echinatus excelled in the pick-up process of radionuclides. The rank decreased in the order: Echinops>Vitex>Cleistanthus>Ocimum>Holorrhoena>Lantana. (author). 14 refs., 2 tabs.

  12. {sup 238}U and {sup 232}Th concentrations in various foodstuffs in Morocco and resulting radiation doses to the members of the public; Concentrations en {sup 238}U et {sup 232}Th dans differents aliments au Maroc et doses de radiations en resultant pour les membres du public

    Energy Technology Data Exchange (ETDEWEB)

    Misdaq, M.A.; Elamyn, H.; Erramli, H. [Cadi Ayyad Univ., Nuclear Physics and Techniques Lab., Faculty of Sciences Semlalia, Marrakech (Morocco)

    2008-04-15

    Uranium ({sup 238}U) and thorium ({sup 232}Th) concentrations were measured in different foods widely consumed in Morocco by using C.R.-39 and L.R.-115 type II solid state nuclear track detectors (S.S.N.T.D.). Data obtained were compared to those obtained by using isotope dilution mass spectrometry (I.D.M.S.). Total daily intakes of {sup 238}U and {sup 232}Th for a typical food basket were estimated to be 1.3 {+-} 0.1 mBq d{sup -1} and 0.98 {+-} 0.08 mBq d{sup -1}, 1.4 {+-} 0.1 mBq d{sup -1} and 1.06 {+-} 0.08 mBq d{sup -1}, 1.7 {+-} 0.1 mBq d{sup -1} and 1.26 {+-} 0.08 mBq d{sup -1} and 2.0 {+-} 0.1 mBq d{sup -1} and 1.5 {+-} 0.1 Bq d{sup -1} for the 2-7 years, 7-12 years, 12-17 years and adult's age groups, respectively. Alpha-activities due to annual {sup 238}U and {sup 232}Th intakes from the ingestion of the studied foodstuffs were determined in different organs and tissues of the human body of members of the public by using the ICRP gastrointestinal tract and systemic part models for these radionuclides. Committed equivalent doses due to annual intakes of {sup 238}U and {sup 232}Th were evaluated in the human body organs and tissues for different age groups of the Moroccan population by exploiting data obtained for alpha-doses deposited by 1 Bq of {sup 238}U and 1 Bq of {sup 232}Th in the considered human organs and tissues. The influence of the mass of the target tissue and activities due to {sup 238}U and {sup 232}Th on the committed equivalent doses due to annual intakes of these radionuclides in the organs and tissues of the human body was studied. (authors)

  13. 238U content in soils of Byelorussia

    International Nuclear Information System (INIS)

    Shagalova, Eh.D.

    1986-01-01

    Results of detection in Byelorussian soils of a heavy natural radionuclide 238 U and its content in humus horizons of the soils on map-schemes are presented. 238 U content is determined by complete decomposition of soils by acids, isolation from thorium using EhDEh-10 P anionite and subsequent solution colorimetry. It is shown that the content of uranium-238 in soils decreases from the North to the South. Its maximum amount (>2x10 -4 %) is detected in turfy-podsolic soils in lake-glacier loams; the minimum one ( -4 %)- in peatymarshy soils. The map-scheme of 238 U content is a background base. Using the background base it is possible to trace the change in uranium content in soils under conditions of technogenic effect and to substantiate the efficiency of environment protection measures

  14. Optimization of the binary breeder reactor. VIII annular core fueled with 233U - 238U and Pu-238U

    International Nuclear Information System (INIS)

    Nascimento, J.A. do; Ishiguro, Y.

    1988-04-01

    First cycle burnup characteristics of a 1200 MWe binary breeder reactor with annular core fueled with metallic 233 U- 238 U-Zr, Pu- 238 U-Zr and Th in the blankets have been analysed. The Doppler effect is small as expected in a metal fueled fast reactor. The sodium void reactivity is, in general, smaller than in metal fueled homogeneous fast reactors of 1 m core height. The estimates of the required and available control rod worths show a large shutdown margin throughout the operational cycle. There are flexibilities in the blanket fueling and well balanced breeding in the two cycles, uranium and thorium, with doubling times of about 20 years are possible. (author) [pt

  15. Ingestion dose from 238U, 232Th, 226Ra, 40K and 137CS in cereals, pulses and drinking water to adult population in a high background radiation area, Odisha (India)

    International Nuclear Information System (INIS)

    Lenka, P.; Sahoo, S. K.; Mohapatra, S.; Patra, A. C.; Dubey, J. S.; Vidyasagar, D.; Tripathi, R. M.; Puranik, V. D.

    2013-01-01

    A natural high background radiation area is located in Chhatrapur, Odisha in the eastern part of India. The inhabitants of this area are exposed to external radiation levels higher than the global average background values, due to the presence of uranium, thorium and its decay products in the monazite sands bearing placer deposits in its beaches. The concentrations of 232 Th, 238 U, 226 Ra, 40 K and 137 Cs were determined in cereals (rice and wheat), pulses and drinking water consumed by the population residing around this region and the corresponding annual ingestion dose was calculated. The annual ingestion doses from cereals, pulses and drinking water varied in the range of 109.4-936.8, 10.2-307.5 and 0.5-2.8 μSv y -1 , respectively. The estimated total annual average effective dose due to the ingestion of these radionuclides in cereals, pulses and drinking water was 530 μSv y -1 . The ingestion dose from cereals was the highest mainly due to a high consumption rate. The highest contribution of dose was found to be from 226 Ra for cereals and drinking water and 40 K was the major dose contributor from the intake of pulses. The contribution of man-made radionuclide 137 Cs to the total dose was found to be minimum. 226 Ra was found to be the largest contributor to ingestion dose from all sources. (authors)

  16. Sub-barrier photofission of 238U

    International Nuclear Information System (INIS)

    Bhandari, B.S.

    Photofission cross section of 238 U below threshold have been calculated using a double humped potential barrier parameterized by smoothly joining four parabolas, and a coulomb potential at and beyond the scission point. Relative strength in the fission channel has been calculated and an attempt has been made to interpret the apparent resonance structures observed recently in photofission experiments of 238 U as excited states of the fission isomer. A set of parameters for a double humped barrier are found which are consistent with known spontaneous fission and isomeric fission half lives. In addition to reproducing satisfactorily the observed resonance structure near threshold, the calculation also predicts several low energy resonances in the cross sections [pt

  17. 238U + n resolved resonance energies

    International Nuclear Information System (INIS)

    Olsen, D.K.; de Saussure, G.; Perez, R.B.; Difilippo, F.C.; Ingle, R.W.

    1978-01-01

    Neutron transmission measurements from 100 eV to 170 keV at 150 m through four 238 U samples are reported. The energy calibration is described, and the resultant 233 U resolved resonance energies are found to be intermediate between those from other workers. In addition, some energies for sharp resonances in 23 Na, 27 Al, 32 S, and 206 Pb are given

  18. Environmental 238U and 232Th concentration measurements in an area of high level natural background radiation at Palong, Johor, Malaysia.

    Science.gov (United States)

    Ramli, A Termizi; Hussein, A Wahab M A; Wood, A Khalik

    2005-01-01

    Concentrations of uranium-238 and thorium-232 in soil, water, grass, moss and oil-palm fruit samples collected from an area of high background radiation were determined using neutron activation analysis (NAA). U-238 concentration in soil ranged from 4.9 mg kg(-1) (58.8 Bq kg(-1)) to 40.4 mg kg(-1) (484.8 Bq kg(-1)), Th-232 concentration ranged from 14.9 mg kg(-1) (59.6 Bq kg(-1)) to 301.0 mg kg(-1) (1204 Bq kg(-1)). The concentration of U-238 in grass samples ranged from below the detection limit to 0.076 mg kg(-1) (912 mBq kg(-1)), and Th-232 ranged from 0.008 mg kg(-1) (32 mBq kg(-1)) to 0.343 mg kg(-1) (1.372 Bq kg(-1)). U-238 content in water samples ranged from 0.33 mg kg(-1) (4.0 Bq L(-1)) to 1.40 mg kg(-1) (16.8 Bq L(-1)), and Th-232 ranged from 0.19 mg kg(-1) (0.76 Bq L(-1)) to 0.66 mg kg(-1) (2.64 Bq L(-1)). It can be said that the concentrations of environmental U-238 and Th-232 in grass and water samples in the study area are insignificant. Mosses were found to be possible bio-radiological indicators due to their high absorption of the heavy radioelements from the environment.

  19. Phosphate fertilizer influence on {sup 238} U content in vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Lauria D, C.; Rodrigues S, J.I. [Instituto de Radioprotecao e Dosimetria (IRD/CNEN), Av. Salvador Allende s/n, Rio de Janeiro-RJ (Brazil); Ribeiro, F.C.A. [Centro Regional de Ciencias Nucleares (CRCN/CNEN) Av. Prof. Luiz Freire 200 Cidade Universitaria Recife-PE (Brazil)]. e-mail: dejanira@ird.gov.br

    2006-07-01

    Uranium is a naturally radioactive element, which is usually found in soils, superficial and ground water, vegetables and animals. After ingestion by human beings, most is excreted in few days by feces and urine, without reaching the bloodstream. However, a small part circulates through the body, being accumulated in the soft tissues, as kidneys. A minor fraction can remain in bones per some years, being able through the radioactive decay to irradiate adjacent tissues. Phosphate fertilizers used in conventional crop management can present variable amounts of uranium. In accordance with origin and use, the fertilizer can raise the content of this element in vegetables, and consequently to increase the human exposure for radiation due the consumption of vegetables. It is estimated that the use of phosphate fertilizer has at least doubled the prolonged exposure of humans from ingestion of food. This work aims to evaluate the contribution of organic and chemical fertilizer on the concentration of {sup 238} U in vegetable samples. An experiment with black beans (a very important vegetable for Brazilian people) was conducted in a field which soil has never been fertilized with any sort of fertilizer, located near to the Rio de Janeiro city. On the organic management, bovine manure was used, while on conventional management urea, potassium chloride and superphosphate were used. Simultaneously, black bean samples from not fertilized management were collected. In addition, lettuce and carrot samples from organic and conventional managements were collected in Nova Friburgo farms (the most important vegetable supplier of Rio de Janeiro city market). The analyses of {sup 238} U have been carried out by conventional fluorimetric method. The geometric mean of {sup 238} U concentrations in the carrot and lettuce samples from conventional management were similar with those from organic management, while for beans the conventional samples had higher values than those ones found in

  20. Phosphate fertilizer influence on 238 U content in vegetables

    International Nuclear Information System (INIS)

    Lauria D, C.; Rodrigues S, J.I.; Ribeiro, F.C.A.

    2006-01-01

    Uranium is a naturally radioactive element, which is usually found in soils, superficial and ground water, vegetables and animals. After ingestion by human beings, most is excreted in few days by feces and urine, without reaching the bloodstream. However, a small part circulates through the body, being accumulated in the soft tissues, as kidneys. A minor fraction can remain in bones per some years, being able through the radioactive decay to irradiate adjacent tissues. Phosphate fertilizers used in conventional crop management can present variable amounts of uranium. In accordance with origin and use, the fertilizer can raise the content of this element in vegetables, and consequently to increase the human exposure for radiation due the consumption of vegetables. It is estimated that the use of phosphate fertilizer has at least doubled the prolonged exposure of humans from ingestion of food. This work aims to evaluate the contribution of organic and chemical fertilizer on the concentration of 238 U in vegetable samples. An experiment with black beans (a very important vegetable for Brazilian people) was conducted in a field which soil has never been fertilized with any sort of fertilizer, located near to the Rio de Janeiro city. On the organic management, bovine manure was used, while on conventional management urea, potassium chloride and superphosphate were used. Simultaneously, black bean samples from not fertilized management were collected. In addition, lettuce and carrot samples from organic and conventional managements were collected in Nova Friburgo farms (the most important vegetable supplier of Rio de Janeiro city market). The analyses of 238 U have been carried out by conventional fluorimetric method. The geometric mean of 238 U concentrations in the carrot and lettuce samples from conventional management were similar with those from organic management, while for beans the conventional samples had higher values than those ones found in organic management

  1. Search for surviving actinides and superheavy nuclei in damped collisions of 238U with 238U and 248Cm

    International Nuclear Information System (INIS)

    Kratz, J.V.

    1980-03-01

    In the present talk aspects of the reaction mechanism related to the survival probability of the heaviest fragments in 238 U + 238 U collisions are discussed first. This is followed by a description of the experiments that have been performed to search for surviving superheavy fragments in the 238 U + 238 U reaction and by a presentation of the results obtained so far. In a third section our recent first attempts with the 238 U + 248 Cm reaction are described and preliminary results are discussed. (orig.)

  2. Modelling of the radioactive daughter elements in soil to assess radiation impact due to contaminated irrigation water by parents of 231Pa, 226Ra, 238U, 237Np and 239Pu

    International Nuclear Information System (INIS)

    Bela Kanyar; Katalin Eged; Tunde Katona; Gerhard Proehl; Ulla Bergstroem; Bengt Hallberg; Shelly Mobbs; Geert Olyslaegers; Theo Zeevaert; Palome Pinedo; Inmaculade Simon

    2004-01-01

    Radioactive wastes may contain both parent and daughter radionuclides. In some cases the transfer parameters of the daughter radio-elements differ significantly from that of the parent ones and therefore the dose contributions in the different pathways might be important to assess separately. The present work has compared 5 different site specific models by a scenario, using contaminated water for drinking and irrigation. Altogether 5 radionuclides from the investigated 10 ones contained radioactive daughter elements. In general, for long term studies in biosphere the steady-state formulations of processes are adequate to assess the contamination, except the infiltration into the deeper soil and sediment layers. According to the results of the modelling and computer simulations, the following daughters are to be assessed separately from their parents with respect to the radiation impact: for parent 231 Pa the daughter 227 Ac, for parent 226 Ra the daughters 222 Rn, 210 Pb and 210 Po and for parent 237 Np the daughter 233 Pa. The dose contributions of the daughters from parents 238 U and 239 Pu are less significant during the considered 100-10000 years. In case of contamination of irrigation water with 1 Bq x m -3 of the parent radionuclide 231 Pa, more than 90% of the external dose from soil exposure comes from the daughter 227 Ac (annually 15 nSv). By a similar contamination with 226 Ra as a parent radionuclide, 60% of the ingestion dose is due to food contamination with the daughters 210 Pb and 210 Po (approximately 150 nSv x a -1 ). (author)

  3. Neutron data evaluation of {sup 238}U

    Energy Technology Data Exchange (ETDEWEB)

    Maslov, V.M.; Porodzinskij, Y.V.; Hasegawa, Akira; Shibata, Keiichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-08-01

    Cross sections for neutron-induced reactions on {sup 238}U are calculated by using the Hauser-Feshbach-Moldauer theory, the coupled channel model and the double-humped fission barrier model. The direct excitation of ground state band levels is calculated with a rigid-rotator model. The direct excitation of vibrational octupole and K = 2{sup +} quadrupole bands is included using a soft (deformable) rotator model. The competition of inelastic scattering to fission reaction is shown to be sensitive to the target nucleus level density at excitations above the pairing gap. As for fission, (n,2n), (n,3n), and (n,4n) reactions, secondary neutron spectra data are consistently reproduced. Pre-equilibrium emission of first neutron is included. Shell effects in the level densities are shown to be important for estimation of energy dependence of non-emissive fission cross section. (author). 105 refs.

  4. Internal dose assessment of 238U contaminated soils based on in-vitro gastrointestinal protocol

    Science.gov (United States)

    Perama, Yasmin Mohd Idris; Rashid, Nur Shahidah Abdul; Majid, Amran Ab.; Siong, Khoo Kok

    2017-01-01

    Human exposure to natural radioactive uranium has been a great interest as more industrial rapidly growing contributes to radiation risks. The aim of this case study was to determine the internal dose in humans incorporated with ingestion of 238U contaminated soils. A gastrointestinal analogue test was employed to simulate the human digestive tract. In-vitro approach via German DIN 19738 model was developed in order to estimate the internal exposure of 238U due to ingestion of different types of soils. Synthetic gastrointestinal fluids assay via in-vitro method were produced to determine the concentration of 238U in various soils using ICP-MS. Based on the results, concentration of 238U in BRIS, laterite, peat and alluvium soils were in ranged between (0.0061 ± 0.0057 - 0.0488 ± 0.0148) ppm and (0.0005 ± 0.0004 - 0.0046 ± 0.0007) ppm in gastric and gastrointestinal phase respectively. Types of soil compositions and pH medium were some of the factors that influence mobilization and solubility of 238U contaminanted soil into the digestive juices that resembles human gastrointestinal tract. For the purpose of internal dose assessment, the committed efective dose from 238U intake in soils ranged between 1.237 × 10-11 - 9.8993 × 10-11 Sv y-1 for gastric phase and 1.0184 × 10-12 - 9.3294 × 10-12 Sv y-1 for gastric-intestinal phase. The internal dose measurements from this study were much lower from the recommended values. Hence, ingestion of 238U contaminated soils would not be expected to pose major health risk to humans.

  5. Intake of 210Po, 234U and 238U radionuclides with beer in Poland

    International Nuclear Information System (INIS)

    Skwarzec, B.; Struminska, D.I.; Borylo, A.; Falandysz, J.

    2004-01-01

    238 U, 234 U and 210 Po activity concentrations were determined in beer in Poland by alpha-spectrometry with low-level activity silicon detectors. The results revealed that the mean concentrations of 238 U, 234 U and 210 Po in the analyzed beer samples were 4.63, 4.11 and 4.94 mBq x dm -3 , respectively, the highest in Tyskie (5.71 for 210 Po, 5.06 for 234 U and 6.11 for 238 U) and the lowest in Lech (2.49 for 210 Po). The effective radiation dose due to uranium and polonium ingestions by beer was calculated and were compared to the effective radiation dose from drinking water. (author)

  6. The metrological activity determination of 238 U and 230 Th by gamma spectrometry to industrial fuel-cycle application

    International Nuclear Information System (INIS)

    Almeida M, M.C. de; Delgado, J.U.; Poledna, R.

    2006-01-01

    This work describes the difficulty for determining the activity of 238 U and 230 Th using gamma spectrometry due to the low gamma-ray emission probabilities of 92 and 67 keV, and, mainly, the associated high uncertainties about 13 and 11%, respectively. 230 Th is a 238 U daughter and it is product from uranium mills and refineries. 230 Th decays to 226 Ra and this decay has to be measured because these radionuclides are not in secular equilibrium with their daughter products, besides the gamma-energies have high uncertainties in the emission probabilities. These radionuclides, mostly 238 U, are important in the nuclear fuel-cycle, since the mining of uranium ore, where the nominal isotopic content of natural uranium is 99.27% of 238 U, until the irradiated fuel reprocessing, where this isotope, a fertile material, is recovered to be used again. The uranium and thorium are considered safeguarded nuclear materials and the metrology tries to calibrate and standardize these materials to improve the activity determination techniques applied in different fuel-cycle scopes. The essential characteristics of the safeguarded materials are low gamma energies (less than 100 keV) and emission probabilities but with high uncertainties. In this way, the metrology can contribute to homeland security defense against illicit nuclear trafficking with the identification and quantification of the safeguarded radionuclides such as uranium and thorium, using specific gamma window energy and high resolution planar or coaxial germanium detector. The efficiency curve is obtained from the reference source spectrum considering the photopeak areas corresponding the standard activities. This curve depends on radiation energy, sample geometry, photon attenuation (sample absorption and material absorption between sample-detector), dead time and sample-detector position. The metrological activity determinations of 238 U solid sources, and of 230 Th, in solution (5 ml flask), were performed using

  7. Neutron capture cross-section measurements for 238U between 0.4 and 1.4 MeV

    Science.gov (United States)

    Krishichayan, Fnu; Finch, S. W.; Howell, C. R.; Tonchev, A. P.; Tornow, W.

    2017-09-01

    Neutron-induced radiative-capture cross-section data of 238U are crucial for fundamental nuclear physics as well as for Stewardship Science, for advanced-fuel-cycle calculations, and for nuclear astrophysics. Based on different techniques, there are a large number of 238U(n, γ) 239U cross-section data available in the literature. However, there is a lack of systematic and consistent measurements in the 0.1 to 3.0 MeV energy range. The goal of the neutron-capture project at TUNL is to provide accurate 238U(n, γ) 239U cross-section data in this energy range. The 238U samples, sandwiched between gold foils of the same size, were irradiated for 8-14 hours with monoenergetic neutrons. To avoid any contribution from thermal neutrons, the 238U and 197Au targets were placed inside of a thin-walled pill-box made of 238U. Finally, the whole pill-box was wrapped in a gold foil as well. After irradiation, the samples were gamma-counted at the TUNL's low-background counting facility using high-efficient HPGe detectors. The 197Au monitor foils were used to calculate the neutron flux. The experimental technique and 238U(n, γ) 239U cross-section results at 6 energies will be discussed during the meeting.

  8. Comparison of the BNAB-78 and ENDF/B-V evaluated 238U radiative capture data in the energy range from 0.5 to 15 MeV

    International Nuclear Information System (INIS)

    Tolstikov, V.A.

    1991-01-01

    Evaluations of the 238 U capture cross-section as given in the BNAB-78 and ENDF/B-V evaluated data libraries are intercompared and their values compared to recently published data which had not been included in these evaluations. It is concluded that there is a need to re-assess the earlier experimental data, particularly those based on activation measurements, taking secondary neutron reactions and scattering effects into account. It is recommended that a precision measurement of the capture cross-section and its dependence on energy be done in the 1-7 MeV energy range. (author). 18 refs, 1 fig

  9. Absolute measurement of the cross sections of neutron radiative capture for 23Na, Cr, 55Mn, Fe, Ni, 103Rh, Ta, 197Au and 238U in the 10-600keV energy range

    International Nuclear Information System (INIS)

    Le Rigoleur, Claude; Arnaud, Andre; Taste, Jean.

    1976-10-01

    The total energy weighting technique has been applied to measuring absolute neutron capture cross sections for 23 Na, Cr, 55 Mn, Fe, Ni, 103 Rh, Ta, 197 Au, 238 U in the 10-600keV energy range. A non hydrogeneous liquid scintillator was used to detect the gamma from the cascade. The neutron flux was measured with a 10 B INa(Tl) detector or a 6 Li glass scintillator of well known efficiency. The fast time-of-flight technique was used with on line digital computer data processing [fr

  10. Delayed neutron yield from fast neutron induced fission of 238U

    International Nuclear Information System (INIS)

    Piksaikin, V.M.; Kazakov, L.E.; Isaev, S.G.; Roshchenko, V.A.; Goverdovski, A.A.; Tertytchnyi, R.G.

    2002-01-01

    The measurements of the total delayed neutron yield from fast neutron induced fission of 238 U were made. The experimental method based on the periodic irradiation of the fissionable sample by neutrons from a suitable nuclear reaction had been employed. The preliminary results on the energy dependence of the total delayed neutron yield from fission of 238 U are obtained. According to the comparison of experimental data with our prediction based on correlation properties of delayed neutron characteristics, it is concluded that the value of the total delayed neutron yield near the threshold of (n,f) reaction is not a constant. (author)

  11. Multimode approximation for {sup 238}U photofission at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Demekhina, N. A., E-mail: demekhina@lnr.jinr.ru [Yerevan Physics Institute (Armenia); Karapetyan, G. S. [Yerevan State University (Armenia)

    2008-01-15

    The yields of products originating from {sup 238}U photofission are measured at the bremsstrahlung endpoint energies of 50 and 3500 MeV. Charge and mass distributions of fission fragments are obtained. Symmetric and asymmetric channels in {sup 238}U photofission are singled out on the basis of the model of multimode fission. This decomposition makes it possible to estimate the contributions of various fission components and to calculate the fissilities of {sup 238}U in the photon-energy regions under study.

  12. Electron scattering from the octupole band in 238U

    International Nuclear Information System (INIS)

    Hirsch, A.; Creswell, C.; Bertozzi, W.; Heisenberg, J.; Hynes, M.V.; Kowalski, S.; Miska, H.; Norum, B.; Rad, F.N.; Sargent, C.P.; Sasanuma, T.; Turchinetz, W.

    1978-01-01

    A simple model for nuclear surface vibrations in permanently deformed nuclei does well in reproducing electron scattering cross sections of rotational levels built on a K/sup π/= 0 - intrinsic octupole vibration in 238 U

  13. Present status of radiochemical double β decay study (238U)

    International Nuclear Information System (INIS)

    Chevallier, A.; Chevallier, J.; Escoubes, B.; Schulz, N.; Sens, J.C.; Madic, C.; Maillard, C.

    1989-01-01

    The reasons for which the 238 U is a suitable candidate for the β β decay processes are explained. The strategy adopted for the radiochemical separation of the 234 U is given. A chemical system based on extraction chromatography is applied. The Pu IV breakthrough curves obtained at 40C during 238 Pu/ 238 U separation cycles are presented. A short description of the chromatographic facility is given. The solution adopted for the low background α spectrometer is explained

  14. Photofission product yields of {sup 238}U and {sup 239}Pu with 22-MeV bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Xianfei; Yang, Haori, E-mail: haori.yang@oregonstate.edu

    2016-06-11

    In homeland security and nuclear safeguards applications, non-destructive techniques to identify and quantify special nuclear materials are in great demand. Although nuclear materials naturally emit characteristic radiation (e.g. neutrons, γ-rays), their intensity and energy are normally low. Furthermore, such radiation could be intentionally shielded with ease or buried in high-level background. Active interrogation techniques based on photofission have been identified as effective assay approaches to address this issue. In designing such assay systems, nuclear data, like photofission product yields, plays a crucial role. Although fission yields for neutron-induced reactions have been well studied and readily available in various nuclear databases, data on photofission product yields is rather scarce. This poses a great challenge to the application of photofission techniques. In this work, short-lived high-energy delayed γ-rays from photofission of {sup 238}U were measured in between linac pulses. In addition, a list-mode system was developed to measure relatively long-lived delayed γ-rays from photofission of {sup 238}U and {sup 239}Pu after the irradiation. Time and energy information of each γ-ray event were simultaneously recorded by this system. Cumulative photofission product yields were then determined using the measured delayed γ-ray spectra.

  15. 238U, 234U and 232Th in seawater

    International Nuclear Information System (INIS)

    Chen, J.H.; Edwards, R.L.; Wasserburg, G.J.

    1986-01-01

    We have developed techniques to determine 238 U, 234 U and 232 Th concentrations in seawater by isotope dilution mass spectrometry. Using these techniques, we have measured 238 U, 234 U and 232 Th in vertical profiles of unfiltered, acidified seawater from the Atlantic and 238 U and 234 U in vertical profiles from the Pacific. Determinations of 234 U/ 238 U at depths ranging from 0 to 4900 m in the Atlantic (7 0 44'N, 40 0 43'W) and the Pacific (14 0 41'N, 160 0 01'W) Oceans are the same within experimental error (±5per mille, 2σ). The average of these 234 U/ 238 U measurements is 144±2per mille (2σ) higher than the equilibrium ratio of 5.472 x 10 -5 . U concentrations, normalized to 35per mille salinity, range from 3.162 to 3.281 ng/g, a range of 3.8%. The average concentration of the Pacific samples (31 0 4'N, 159 0 1'W) is ∝1% higher than that of the Atlantic (7 0 44'N, 40 0 43'W and 31 0 49'N, 64 0 6'W). 232 Th concentrations from an Atlantic profile range from 0.092 to 0.145 pg/g. The observed constancy of the 234 U/ 238 U ratio is consistent with the predicted range of 234 U/ 238 U using a simple two-box model and the residence time of deep water in the ocean determined from 14 C. The variation in salinity-normalized U concentrations suggests that U may be much more reactive in the marine environment than previously thought. (orig./WB)

  16. Heterogeneity in the 238U/235U Ratios of Angrites.

    Science.gov (United States)

    Tissot, F.; Dauphas, N.; Grove, T. L.

    2016-12-01

    Angrites are differentiated meteorites of basaltic composition, of either volcanic or plutonic origin, that display minimal post-crystallization alteration, metamorphism, shock or impact brecciation. Because quenched angrites cooled very rapidly, all radiochronometric systems closed simultaneously in these samples. Quenched angrites are thus often used as anchors for cross-calibrating short-lived dating methods (e.g., 26Al-26Mg) and the absolute dating techniques (e.g, Pb-Pb). Due to the constancy of the 238U/235U ratio in natural samples, Pb-Pb ages have long been calculated using a "consensus" 238U/235U ratio, but the discovery of resolvable variations in the 238U/235U ratio of natural samples, means that the U isotopic composition of the material to date also has to be determined in order to obtain high-precision Pb-Pb ages. We set out (a) to measure at high-precision the 238U/235U ratio of a large array of angrites to correct their Pb-Pb ages, and (b) to identify whether all angrites have a similar U isotopic composition, and, if not, what were the processes responsible for this variability. Recently, Brennecka & Wadhwa (2012) suggested that the angrite-parent body had a homogeneous 238U/235U ratio. They reached this conclusion partly because they propagated the uncertainties of the U isotopic composition of the various U double spikes that they used onto the final 238U/235U ratio the sample. Because this error is systematic (i.e., it affects all samples similarly), differences in the δ238U values of samples corrected by the same double spike are better known than one would be led to believe if uncertainties on the spike composition are propagated. At the conference, we will present the results of the high-precision U isotope analyses for six angrite samples: NWA 4590, NWA 4801, NWA 6291, Angra dos Reis, D'Orbigny, and Sahara 99555. We will show that there is some heterogeneity in the δ238U values of the angrites and will discuss the possible processes by

  17. Behavior of uranium along Jucar River (Eastern Spain). Determination of 234U/238U and 235U/238U ratios

    International Nuclear Information System (INIS)

    Rodriguez-Alvarez, M.J.; Sanchez, F.

    1995-01-01

    The uranium concentration and the 234 U/ 238 U, 235 U/ 238 U activity ratios were studied in water samples from Jucar River, using low-level α-spectrometry. The effects of pH, temperature and salinity were considered and more detailed sampling was done in the neighbourhood of Cofrentes Nuclear Plant (Valencia, Spain). Changes were observed in the uranium concentration with the salinity and the 234 U/ 238 U activity ratio was found to vary with pH. Leaching and dilution, which depend on pH and salinity, are the probable mechanisms for these changes in the concentration of uranium and the activity ratios. (author) 25 refs.; 4 figs.; 1 tab

  18. 238U, 234U and 230Th in uranium miners' lungs

    International Nuclear Information System (INIS)

    Singh, N.P.; Wrenn, M.E.; Bennett, D.B.; Archer, V.; Saccomanno, G.

    1982-01-01

    Fourteen uranium miners' lungs from the Colorado Plateau were collected at autopsy and the concentrations of 238 U, 234 U and 230 Th were determined by radiochemical procedures utilizing solvent extraction and alpha spectrometric techniques. The uranium and thorium isotopes are in near equilibrium with average concentrations of 238 U, 234 U and 230 Th being 89.3, 95.2, and 91.1 pCi/kg respectively. The combined average radiation dose rate to lung from these three isotopes is about 24.1 mrad/year at death excluding the unmeasured contribution from the 226 Ra and daughters. The average concentration of 230 Th is about 65 times higher than the mean concentration of 230 Th in lungs of non-miners from the same region dying at comparable ages

  19. 238U, 234U and 230Th in uranium miners' lungs

    International Nuclear Information System (INIS)

    Singh, M.P.; Wrenn, M.E.; Archer, V.E.; Saccomanno, G.

    1981-01-01

    Fourteen uranium miners' lungs from Colorado plateau were collected at autopsy and the concentrations of 238 U, 234 U and 230 Th were determined by radiochemical procedures utilizing solvent extraction - alpha spectrometric techniques. The uranium and thorium isotopes are in near equilibrium with average concentrations of 238 U, 234 U and 230 Th being 89.3, 95.2 and 91.1 pCi/kg respectively. The combined average radiation dose rate to lung from these three isotopes is about 24.2 mrad/year at death excluding the unmeasured contribution from the 226 Ra and daughters. The average concentration of 230 Th is about 65 times higher than the mean concentration of 230 Th in lungs of non-miners dying at comparable ages from the same region

  20. Precise measurement and calculation of 238U neutron transmissions

    International Nuclear Information System (INIS)

    Olsen, D.K.; de Saussure, G.; Silver, E.G.; Perez, R.B.

    1975-01-01

    The total neutron cross section of 238 U has been measured above 0.5 eV in precise transmission experiments and results are compared with ENDF/B-IV. Emphasis has been on measuring transmissions through thick samples in order to obtain accurate total cross sections in the potential-resonance interference regions between resonances. 4 figures, 1 table

  1. 238U subthreshold neutron induced fission cross section

    International Nuclear Information System (INIS)

    Difilippo, F.C.; Perez, R.B.; De Saussure, G.; Olsen, D.K.; Ingle, R.W.

    1976-01-01

    High resolution measurements of the 238 U neutron induced fission cross section are reported for neutron energies between 600 eV and 2 MeV. The average subthreshold fission cross section between 10 and 100 keV was found to be 44 +- 6 μb

  2. Evaluation of covariance for 238U cross sections

    International Nuclear Information System (INIS)

    Kawano, Toshihiko; Nakamura, Masahiro; Matsuda, Nobuyuki; Kanda, Yukinori

    1995-01-01

    Covariances of 238 U are generated using analytic functions for representation of the cross sections. The covariances of the (n,2n) and (n,3n) reactions are derived with a spline function, while the covariances of the total and the inelastic scattering cross section are estimated with a linearized nuclear model calculation. (author)

  3. The metrological activity determination of {sup 238} U and {sup 230} Th by gamma spectrometry to industrial fuel-cycle application

    Energy Technology Data Exchange (ETDEWEB)

    Almeida M, M.C. de; Delgado, J.U.; Poledna, R. [Instituto de Radioprotecao e Dosimetria- IRD/SEMRA, CNEN, Av. Salvador Allende s/n, Recreio, CEP 22780-160, Rio de Janeiro (Brazil)]. e-mail: marcandida@yahoo.com.br

    2006-07-01

    This work describes the difficulty for determining the activity of {sup 238} U and {sup 230} Th using gamma spectrometry due to the low gamma-ray emission probabilities of 92 and 67 keV, and, mainly, the associated high uncertainties about 13 and 11%, respectively. {sup 230} Th is a {sup 238} U daughter and it is product from uranium mills and refineries. {sup 230} Th decays to {sup 226} Ra and this decay has to be measured because these radionuclides are not in secular equilibrium with their daughter products, besides the gamma-energies have high uncertainties in the emission probabilities. These radionuclides, mostly {sup 238} U, are important in the nuclear fuel-cycle, since the mining of uranium ore, where the nominal isotopic content of natural uranium is 99.27% of {sup 238} U, until the irradiated fuel reprocessing, where this isotope, a fertile material, is recovered to be used again. The uranium and thorium are considered safeguarded nuclear materials and the metrology tries to calibrate and standardize these materials to improve the activity determination techniques applied in different fuel-cycle scopes. The essential characteristics of the safeguarded materials are low gamma energies (less than 100 keV) and emission probabilities but with high uncertainties. In this way, the metrology can contribute to homeland security defense against illicit nuclear trafficking with the identification and quantification of the safeguarded radionuclides such as uranium and thorium, using specific gamma window energy and high resolution planar or coaxial germanium detector. The efficiency curve is obtained from the reference source spectrum considering the photopeak areas corresponding the standard activities. This curve depends on radiation energy, sample geometry, photon attenuation (sample absorption and material absorption between sample-detector), dead time and sample-detector position. The metrological activity determinations of {sup 238} U solid sources, and of

  4. Inclusive quasifree electrofission cross section for 238U

    International Nuclear Information System (INIS)

    Likhachev, V.P.; Carvalho, W.R. Jr.; Deppman, A.; Hussein, M.S.; Macedo, L.F.R.; Mesa, J.; Vaudeluci, M.S.; Arruda-Neto, J.D.T.; Evseev, I.G.; Pashchuk, S.A.; Schelin, H.R.; Garcia, F.; Rodriguez, O.; Margaryan, A.; Nesterenko, V.O.

    2003-01-01

    We present results from a joint theoretical and experimental study of inclusive quasifree electrofission of 238 U. The off-shell cross sections for the quasifree reaction stage have been calculated within the plane wave impulse approximation with distortion corrections included in the effective momentum approximation. Proton and neutron single-particle momentum distributions were calculated in the macroscopic-microscopic approach. The fissility for proton and neutron single hole excited states of the residual nuclei 237 Pa and 237,238 U was calculated within the compound nucleus model. Final state interaction corrections to residual nucleus excitation energy were calculated using the imaginary part of the optical potential. The total inclusive electrofission cross section was measured with high absolute precision, and all principal partial contributions are analyzed, in particular, the quasifree one

  5. 230Th-238U disequilibria in historical lavas from Iceland

    International Nuclear Information System (INIS)

    Condomines, M.; Morand, P.; Alleegre, C.J.; Sigvaldason, G.

    1981-01-01

    The 230 Th- 238 U disequilibrium studies on historical lavas from Iceland show a relative homogeneity for Th/U ratios and also a variation for ( 230 Th/ 232 Th) activity ratios at the scale of the island. The ( 230 Th/ 238 U) disequilibrium ratio is always greater than 1 which indicates that partial melting produces magmas with Th/U ratios greater than those of the mantle source. Furthermore, there seems to be a correlation between the variations of ( 230 Th/ 232 Th) (and delta 18 O) ratios and the geographical location of the samples along the active zones of Iceland. We develop and discuss several models in order to explain these variations. (orig.)

  6. Detection limit of 238U by gamma spectrometry

    International Nuclear Information System (INIS)

    Tartaglione, A.; Blostein, J.; Mayer, R

    2004-01-01

    The detection limit of 238 U was determined by gamma spectra measurements of a depleted uranium sample using four NaI(Tl) scintillators in a compact arrangement.The sample was shielded with 5 and 10 cm of lead.Two different methods for data processing were used and compared.It was established that an appropriate array of 40 detectors could establish the presence of 220 g of this material in only 5 minutes [es

  7. Delayed fission of the 238U muonic atom

    International Nuclear Information System (INIS)

    Ganzorig, Dz.; Krogulski, T.; Kuznetsov, V.D.; Polikanov, S.M.; Sabirov, B.M.

    1975-01-01

    The time distributions of fission and muon free decay events with respect to the moment of the muon-stop event have been measured for double and triple coincidences between these three events. The triple-coincidence time distributions give an indication of the o-curence of two new effects: the delayed fission of muonic 238 U atom and conversion of muons from the fission fragments

  8. The evaluation for reference fission yield of 238U fission

    International Nuclear Information System (INIS)

    Liang Qichang; Liu Tingjin

    1998-01-01

    In the fission yield data evaluation and measurement, the reference yield is very important, good or poor recommended or measurement values depend upon the reference data to a great extent. According to the CRP's requirement, the evaluation of reference fission yields have been and will be carried out in CNDC, as a part of the whole work (contract No.9504/R 0 /Regular Budget Fund), the evaluation for 29 reference fission yields of 15 product nuclides from 238 U fission have been completed

  9. Effects on elevating cancer risk in population exposed to natural radionuclide 226Ra if parent radionuclide 238U is entered the body by inhalation or ingestion

    International Nuclear Information System (INIS)

    Zupunski, Lj.; Trobok, M.; Gordanic, V.; Spasic-Jokic, V.; Sovilj, P.

    2009-01-01

    People have always been exposed to ionizing radiation originating from natural radionuclides including 238 U, 40 K, 232 Th that exist in earths crust. Although received doses are small, due to the fact that threshold does not exist, there is a certain risk of developing cancer. Purpose of this study was to measure 238 U concentrations in soil of Bela Crkva territory. Based on these measurements, risks of developing cancers are calculated using Monte Carlo method.(author) [sr

  10. Doppler-free two-photon excitation of 238U

    International Nuclear Information System (INIS)

    Hodgkinson, D.P.; Wort, D.J.H.

    1981-04-01

    A theory of resonantly enhanced two-photon absorption is presented and tested in a number of experiments in which 238 U vapour is excited by two continuous wave dye lasers. Good quantitative agreement between theory and experiment is found. In particular the central prediction of the theory, that antiparallel laser beams of modest intensity can pump an appreciable fraction of the Maxwell velocity distribution, has been checked directly by measuring the spectral width of the fluorescence from the two-photon excited level. (author)

  11. Charge-pickup of 238U at relativistic energies

    International Nuclear Information System (INIS)

    Rubehn, T.; Bassini, R.; Blaich, T.; Imme, G.; Iori, I.; Kunze, W.D.; Lindenstruth, V.; Lynen, U.; Moehlenkamp, T.; Moretto, L.G.; Ocker, B.; Pochodzalla, J.; Raciti, G.; Schuettauf, A.; Serfling, V.; Trautmann, W.; Trzcinski, A.; Verde, G.; Woerner, A.; Zude, E.; Zwieglinski, B.

    1995-10-01

    Cross sections for the charge-pickup of 238 U projectiles were measured at E/A=600 and 1000 MeV for seven different targets (Be, C, Al, Cu, In, Au and U). Events with two fission fragments with a sum charge of 93 in the exit channel were selected. Due to the significant excitation energy, the dominant part of produced Np nuclei fission instead of decaying to the ground state by evaporation. The observed cross sections can be well reproduced by intranuclear-cascade-plus-evaporation calculations and, therefore, confirm recent results that no exotic processes are needed to explain charge-pickup processes. (orig.)

  12. Database for 238U inelastic scattering cross section evaluation

    International Nuclear Information System (INIS)

    Kanda, Yukinori; Fujikawa, Noboru; Kawano, Toshihiko

    1993-10-01

    There are discrepancies among evaluated neutron inelastic scattering cross sections for 238 U in the evaluated nuclear data files, JENDL-3, ENDF/B-VI, JEF-2, BROND-2 and CENDL-2. Re-evaluating them is internationally being discussed to obtain the best outcome which can be accepted in common at the present by experts in the world. This report has been compiled to review the discrepancies among the evaluations in the present data files and to provide a common database for the re-evaluation work (author)

  13. Evaluation of the 238U neutron total cross section

    International Nuclear Information System (INIS)

    Smith, A.; Poenitz, W.P.; Howerton, R.J.

    1982-12-01

    Experimental energy-averaged neutron total cross sections of 238 U were evaluated from 0.044 to 20.0 MeV using regorous numerical methods. The evaluated results are presented together with the associated uncertainties and correlation matrix. They indicate that this energy-averaged neutron total cross section is known to better than 1% over wide energy regions. There are somwewhat larger uncertainties at low energies (e.g., less than or equal to 0.2 MeV), near 8 MeV and above 15 MeV. The present evaluation is compard with values given in ENDF/B-V

  14. Present status of radiochemical double beta decay study (238U)

    International Nuclear Information System (INIS)

    Madic, C.; Maillard, C.; Chevallier, A.; Chevallier, J.; Escoubes, B.; Schulz, N.; Sens, J.C.

    1989-01-01

    A sensitive experiment has been designed that will be able to measure an assumed half-life of 1.9x10 22 yr. This double beta corresponds to the activity of 27000 238 Pu nuclei formed during a year, in a 200 m deep mine, from 300 kg of 238 U, giving 210 alpha decays per year. Plutonium 238 et 239 will be determined by alpha spectroscopy after extraction chromatography. Experimental studies were undertaken to select the best conditions for running the extraction chromatography cycles

  15. Characterization of {sup 238}U, {sup 232}Th, {sup 40}K, and {sup 226}Ra in NORM and Air Particulate Occurring from Phosphate Processing Facility

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yoon Hee; Lim, Jong Myoung; Ji, Young Yong; Kim, Hyun Cheol; Kim, Chang Jong; Park, Ji Yong; Chung, Kun Ho; Kang, Mun Ja [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In this study, radio-activities of {sup 238}U, {sup 232}Th, {sup 40}K, and {sup 226}Ra occurring in raw materials and by-products at phosphate processing facility were complementally determined using ED-XRF, γ-spectrometry and ICP-MS method. Although the degree of immersion in the human body varies depending on the particle size and density, the particle size is especially used as a key factor in assessing dose. Thus, size distribution characteristics of {sup 238}U concentrations in airborne particulates collected at the phosphate processing facility were also evaluated. The naturally occurring radioactive materials (NORM) are widely spread throughout the environment, it occupies the largest part of public radioactivity exposure. According to report of the US National Academy of Sciences, 82% of the human radiation dose received annually comes from the natural radionuclides. Radiation exposure doses from natural radionuclides is not significantly concerned level compared to those from artificial radionuclides which could be released into the environment by nuclear tests and power plant accident. It could make a serious risk problem to unspecific public when exposed to the natural radionuclides during long-term period at high activity concentration levels. Therefore, it is essential to make a professional and systematic approach for the proper handling and diminution.

  16. Precise 238U(n,2n)237U reaction cross-section measurements using the activation facility at TUNL

    Science.gov (United States)

    Krishichayan, Fnu; Bhike, M.; Tornow, W.

    2014-09-01

    Accurate neutron-induced 238U(n,2n)237U reaction data are required for many practical applications, especially in the field of nuclear energy, including advanced heavy water reactors, where 238U is used as the breeding material to regenerate the fissile material 239Pu. Precise (n,2n) cross-section measurements of 238U are underway at TUNL with mono-energetic neutrons in the 8.0 to 14.0 MeV energy range in steps of 0.25 MeV using the activation technique. After activation of the 0.5 inch diameter and 442 mg 238U foil, the activity of the 208 keV characteristic γ-line is tracked for 6 weeks with a high efficient HPGe clover detector to determine the initial activity needed for the cross-section determination. Results of the cross-section measurements, determined relative to 27Al and 197Au neutron activation monitor foils, and the comparison with theoretical models will be presented during the meeting.

  17. 238U-series radionuclides in Finnish groundwater-based drinking water and effective doses

    International Nuclear Information System (INIS)

    Vesterbacka, P.

    2005-09-01

    The thesis deals with the occurrence of 238 U-series radionuclides and particle-bound 210 Pb and 210 Po in Finnish groundwater-based drinking water, methods used for removing 234 U, 238 U, 210 Pb and 210 Po, and the annual effective doses caused by 238 U-series radionuclides in drinking water. In order to reduce radiation exposure and avoid high doses, it is important to examine the activity levels of natural radionuclides in groundwater. In this work, the activity concentrations of radon ( 222 Rn), radium ( 226 Ra), uranium ( 238 U and 234 U), lead ( 210 Pb) and polonium ( 210 Po) were determined from 472 private wells, which were selected randomly from across Finland. On the basis of the results, the activity concentrations in groundwater and the radiation exposure from drinking water of people living outside the public water supply in Finland was specified. The efficiency of 238 U, 234 U, 210 Pb and 210 Po removal from drinking water was examined at ten private homes. In order to obtain accurate results and correct estimates of effective doses, attention was paid to the sampling of 222 Rn and 210 Pb, and the determination of 210 Pb. The results revealed that the median activity concentrations of natural radionuclides were as much as ten times higher in drilled wells than in wells dug in soil. The average activity concentration of 222 Rn in drilled wells was 460 Bq/l and in dug wells 50 Bq/l. The highest activity concentrations were found in Southern Finland. In addition, occasional high activity concentrations were found all over Finland. The average activity concentrations of 234 U and 238 U in drilled wells were 0.35 and 0.26 Bq/l and in dug wells 0.020 and 0.015 Bq/l, respectively. The spatial distribution of 234 U, 238 U, 210 Pb and 210 Po was essentially similar to that of 222 Rn. In contrast to other natural radionuclides, the highest 226 Ra activity concentrations were found in coastal areas, since drilled well water near the sea has a higher salinity

  18. 226Ra/238U disequilibrium in an upland organic soil exhibiting elevated natural radioactivity

    International Nuclear Information System (INIS)

    Dowdall, M.; O'Dea, J.

    2002-01-01

    This paper presents the results of a study into the anomalous 226 Ra/ 238 U disequilibrium ( 226 Ra/ 238 U of 0.5-9) exhibited by an upland organic soil in Co. Donegal, Ireland. Radiochemical speciation of 226 Ra, 238 U and 228 Ra indicates that in this organic soil the high 226 Ra/ 238 U ratio is due to loss of 238 U relative to 226 Ra via oxidation and mobilisation of 238 U in the upper layers of the soil and subsequent loss in solution. At the lower, more reducing depths of the soil profile, 238 U and 226 Ra are essentially in equilibrium. Loss of 238 U appears to occur primarily from the easily oxidised organic and iron oxide fractions of the soil, samples exhibiting high 226 Ra/ 238 U ratios displaying significantly lower 238 U levels in these fractions than samples whose ratio is below the average value for the soil of the valley. Selective enrichment of 226 Ra by plants or preferential leaching of 226 Ra from the underlying rock is not supported by the results of this study

  19. Determination of specific concentrations of 40K, 238U and 232Th in mineral fertilizer samples

    International Nuclear Information System (INIS)

    Garcez, Ricardo W.D.; Lopes, Jose M.; Silva, Ademir X.

    2015-01-01

    The use of fertilizer is an established practice worldwide to promote agricultural productivity increased without increasing the planted area, resulting in native forests protection and increase of the food availability. Some kinds of fertilizer have in their chemical composition some radionuclides due the origin of its feedstock, such as 238 U, the 232 Th, and their descendants, beyond 40 K. Knowledge of the radioactivity levels in the environment is great importance to know the gamma radiation dose that the human being is exposed. For identification and quantitation of radionuclides, it was used gamma spectrometry where HPGe detector was used to obtain the spectra, and LabSOCS software for calculating the detection efficiency for each energy. The values of 232 Th specific concentrations ranged from 4.1 to 368.1 Bq.Kg -1 , the values of 238 U specific concentrations ranged from 16.0 to 647.7 Bq.Kg -1 and 40 K specific concentrations ranged from 19.1 to 12713 Bq.Kg -1 . Concentrations of values are consistent with those found in literature. (author)

  20. New evaluation of 238U neutron resonance parameters

    International Nuclear Information System (INIS)

    Derrien, Herve; Leal, Luiz C.; Larson, Nancy M.

    2003-01-01

    The neutron resonance parameters of 238 U were obtained in the energy range 1 keV to 20 keV from a SAMMY Reich-Moore analysis of high resolution transmission measurements performed at ORELA. In the energy range 1 keV to 10 keV, the analysis used as prior values the ENDF/B-VI resonance parameters. The analysis in the energy range 10 keV to 20 keV resulted in the creation of a set of resonance parameters for the representation of the cross section in this energy range. The results are compared to the ENDF/B-VI evaluation. Some statistical properties of the new resonance parameters are examined. (author)

  1. Neutron Induced Capture and Fission Processes on 238U

    Directory of Open Access Journals (Sweden)

    Oprea Cristiana

    2016-01-01

    Full Text Available Nuclear data on Uranium isotopes are of crucial interest for new generation of nuclear reactors. Processes of interest are the nuclear reactions induced by neutrons and in this work mainly the capture and the fission process on 238U will be analyzed in a wide energy interval. For slow and resonant neutrons the many levels Breit – Wigner formalism is necessary. In the case of fast and very fast neutrons up to 200 MeV the nuclear reaction mechanism implemented in Talys will be used. The present evaluations are necessary in order to obtain the field of neutrons in the design of nuclear reactors and they are compared with experimental data from literature obtained from capture and (n,xn processes.

  2. Light nuclides produced in the proton-induced spallation of {sup 238}U at 1 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardi, M.V.; Armbruster, P. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Benlliure, J. [Universidad de Santiago de Compostela (ES)] [and others

    2005-09-01

    The production of light and intermediate-mass nuclides formed in the reaction {sup 1}H+{sup 238}U at 1 GeV was measured at the fragment separator (FRS) at GSI, Darmstadt. The experiment was performed in inverse kinematics, shooting a 1 A GeV {sup 238}U beam on a thin liquid-hydrogen target. 254 isotopes of all elements in the range 7{<=}Z{<=}37 were unambiguously identified, and the velocity distributions of the produced nuclides were determined with high precision. The results show that the nuclides are produced in a very asymmetric binary decay of heavy nuclei originating from the spallation of uranium. All the features of the produced nuclides merge with the characteristics of the fission products as their mass increases. (orig.)

  3. 238U-230Th radioactive disequilibria in the volcanic products from Izu arc volcanoes, Japan

    International Nuclear Information System (INIS)

    Kurihara, Yuichi; Takahashi, Masaomi; Sato, Jun

    2007-01-01

    The timescale of magmatic processes of Izu arc volcanoes, Japan, was estimated by the 238 U- 230 Th disequilibria in the volcanic products from the volcanoes. The majority of the 230 Th/ 238 U activity ratios of the products were less than unity, being enriched in 238 U relative to 230 Th. The ( 230 Th/ 232 Th)-( 238 U/ 232 Th)diagram for younger Fuji and Izu-Oshima volcanoes formed a whole rock isochrons, and the ages were 1x10 4 and 2x10 4 years, respectively. The ( 230 Th/ 232 Th) - ( 238 U/ 232 Th) data set for younger Fuji volcano formed a cluster on the diagram, while those of Izu-Oshima formed another cluster apparently apart from each other, suggesting that the concentration of U and Th may possibly be un-uniform in the mantle beneath Izu arc. (author)

  4. Isotopic resolution of fission fragments from 238U + 12C transfer and fusion reactions

    International Nuclear Information System (INIS)

    Caamano, M.; Rejmund, F.; Derkx, X.; Schmidt, K. H.; Andouin, L.; Bacri, C. O.; Barreau, G.; Benlliure, J.; Casarejos, E.; Fernandez-Dominguez, B.; Gaudefroy, L.; Golabek, C.; Jurado, B.; Lemasson, A.; Navin, A.; Rejmund, M.; Roger, T.; Shrivastava, A.; Schmitt, C.; Taieb, J.

    2010-01-01

    Recent results from an experiment at GANIL, performed to investigate the main properties of fission-fragment yields and energy distributions in different fissioning nuclei as a function of the excitation energy, in a neutron-rich region of actinides, are presented. Transfer reactions in inverse kinematics between a 238 U beam and a 12 C target produced different actinides, within a range of excitation energy below 30 MeV. These fissioning nuclei are identified by detecting the target-like recoil, and their kinetic and excitation energy are determined from the reconstruction of the transfer reaction. The large-acceptance spectrometer VAMOS was used to identify the mass, atomic number and charge state of the fission fragments in flight. As a result, the characteristics of the fission-fragment isotopic distributions of a variety of neutron-rich actinides are observed for the first time over the complete range of fission fragments. (authors)

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

    International Nuclear Information System (INIS)

    Nicholas, T.; Bingham, D.

    2011-01-01

    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. (authors)

  6. 238 U, 232 Th and 40 K in wheat flour samples of Iraq markets

    Directory of Open Access Journals (Sweden)

    Ali Abid Abojassim

    2015-05-01

    Full Text Available Introduction. Wheat flour is a nutritious type of food that is widely consumed by various age groups in Iraq. This study investigates the presence of long-lived gamma emitters in different type of wheat flour in Iraqi market. Materials and methods. Uranium (238 U, Thorium (232 Th and Potassium (40 K specific activity in (Bq/kg were measured in (12 different types of wheat flours that are available in Iraqi markets. The gamma spectrometry method with a NaI(Tl detector has been used for radiometric measurements. Also in this study we have calculated the internal hazard index, radium equivalent and absorbed dose rate in all samples. Results and discussion. It is found that the specific activity in wheat flour samples were varied from (1.086±0.0866 Bq/kg to (12.532±2.026 Bq/kg with an average (6.6025 Bq/kg for 238 U, For 232 Th From (0.126±0.066 Bq/kg to (4.298±0.388 Bq/kg with an average (1.9465Bq/kg and for 40 K from (41.842±5.875 Bq/kg to (264.729±3.843 Bq/kg with an average (133.097 Bq/kg. Also, it is found that the radium equivalent and the internal hazard index in wheat flour samples ranged from (3.4031 Bq/kg to (35.1523 Bq/kg with an average (19.6346 Bq/kg and from (0.0091 to (0.1219 with an average (0.0708 respectively. Conclusion. This study prove that the natural radioactivity and radiation hazard indices were lower than the safe.

  7. Determination of 238U in marine organisms by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Ishii, Toshiaki; Nakahara, Motokazu; Matsuba, Mitsue; Ishikawa, Masafumi

    1991-01-01

    Determination of 238 U in fifty-five species of marine organisms was carried out by inductively coupled plasma mass spectrometry which showed some advantages such as high sensitivity, wide dynamic range and small interferences from matrices for the analysis of high mass elements. The concentrations of 238 U in soft tissues of marine animals ranged from 0.076 to 5000 ng/g wet wt. Especially, the branchial heart of cephalopod molluscs showed the specific accumulation of 238 U. The concentration factor of the branchial heart of Octopus vulgaris, which indicated the highest value, was calculated to be about 10 3 by comparing it with the concentration of 238 U (3.2±0.2 ng/ml) in coastal seawaters of Japan. The concentrations of 238 U in hard tissues of marine invertebrates were similar to those in soft tissues. In contrast, hard tissues like bone, scale, fin, etc. of fishes showed much higher concentrations of 238 U than soft tissues like muscle and liver. The concentrations of 238 U of twenty species of algae ranged from 10 to 3700 ng/g dry wt. (author)

  8. Limitations on the precision of 238U/235U measurements and implications for environmental monitoring

    International Nuclear Information System (INIS)

    Russ III, G.P.

    1997-01-01

    The ability to determine the isotopic composition of uranium in environmental samples is an important component of the International Atomic Energy Agency's (IAEA) safeguards program, and variations in the isotopic ratio 238 U/ 235 U provide the most direct evidence of isotopic enrichment activities. The interpretation of observed variations in 238 U/ 235 U depends on the ability to distinguish enrichment from instrumental biases and any variations occurring in the environment but not related to enrichment activities. Instrumental biases that have historically limited the accuracy of 238 U/ 235 U determinations can be eliminated by the use of the 233 U/ 236 U double-spike technique. With this technique, it is possible to determine the 238 U/ 235 U in samples to an accuracy equal to the precision of the measurement, ca. 0.1% for a few 10's of nanograms of uranium. Given an accurate determination of 238 U/ 235 U, positive identification of enrichment activities depends on the observed value being outside the range of 238 U/ 235 U's expected as a result of natural or environmental variations. Analyses of a suite of soil samples showed no variation beyond 0.2% in 238 U/ 235 U

  9. Determination of the isotopic ratio 234 U/238 U and 235 U/238 U in uranium commercial reagents by alpha spectroscopy

    International Nuclear Information System (INIS)

    Iturbe G, J.L.

    1990-02-01

    In this work the determination of the isotope ratio 234 U/ 238 U and 235 U/ 238 U obtained by means of the alpha spectroscopy technique in uranium reagents of commercial marks is presented. The analyzed uranium reagents were: UO 2 (*) nuclear purity, UO 3 (*) poly-science, metallic uranium, uranyl nitrate and uranyl acetate Merck, uranyl acetate and uranyl nitrate Baker, uranyl nitrate (*) of the Refinement and Conversion Department of the ININ, uranyl acetate (*) Medi-Lab Sigma of Mexico and uranyl nitrate Em Science. The obtained results show that the reagents that are suitable with asterisk (*) are in radioactive balance among the one 234 U/ 238 U, since the obtained value went near to the unit. In the case of the isotope ratio 235 U/ 238 U the near value was also obtained the one that marks the literature that is to say 0.04347, what indicates that these reagents contain the isotope of 235 U in the percentage found in the nature of 0.71%. The other reagents are in radioactive imbalance among the 234 U/ 238 U, the found values fluctuated between 0.4187 and 0.1677, and for the quotient of activities 235 U/ 238 U its were of 0.0226, and the lowest of 0.01084. Also in these reagents it was at the 236 U as impurity. The isotope of 236 U is an isotope produced artificially, for what is supposed that the reagents that are in radioactive imbalance were synthesized starting from irradiated fuel. (Author)

  10. Dissolution behaviour of 238U, 234U and 230Th deposited on filters from personal dosemeters.

    Science.gov (United States)

    Becková, Vera; Malátová, Irena

    2008-01-01

    Kinetics of dissolution of (238)U, (234)U and (230)Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultrafiltrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolní Rozínka' at Rozná, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h(-1) and the sampling period is typically 1 month. Studied filters contained 125 +/- 6 mBq (238)U in equilibrium with (234)U and (230)Th; no (232)Th series nuclides were found. Half-time of rapid dissolution of 1.4 d for (238)U and (234)U and slow dissolution half-times of 173 and 116 d were found for (238)U and (234)U, respectively. No detectable dissolution of (230)Th was found.

  11. Dissolution behaviour of 238U, 234U and 230Th deposited on filters from personal dosemeters

    International Nuclear Information System (INIS)

    Beckova, V.; Malatova, I.

    2008-01-01

    Kinetics of dissolution of 238 U, 234 U and 230 Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultra-filtrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolni Rozinka' at Rozna, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h -1 and the sampling period is typically 1 month. Studied filters contained 125 ± 6 mBq 238 U in equilibrium with 234 U and 230 Th; no 232 Th series nuclides were found. Half-time of rapid dissolution of 1.4 d for 238 U and 234 U and slow dissolution half-times of 173 and 116 d were found for 238 U and 234 U, respectively. No detectable dissolution of 230 Th was found. (authors)

  12. 238U photonuclear studies with 5-10 MeV photons

    International Nuclear Information System (INIS)

    Hawkes, N.P.

    1986-02-01

    The 238 U photofission and photoneutron cross sections, and the mean number -ν of prompt neutrons per fission, have been measured between 5 and 10 MeV. The experiment was carried out using bremsstrahlung from the electron linear accelerator HELIOS at Harwell. Neutrons from (γ,f) and (γ,n) reactions on 238 U were detected, and neutron multiplicity distributions recorded. Photoneutron events were separated from photofission events by means of their different multiplicities. (author)

  13. Evaluation of neutron-induced reactions in 48Ti and 238U

    International Nuclear Information System (INIS)

    Carlson, B.V.; Fiorentino, J.; Frederico, T.; Isidro Filho, M.P.; Mastroleo, R.C.; Rego, R.A.

    1984-05-01

    Preliminary results of the evaluation of neutron-induced reactions in 48 Ti and 238 U are presented. Calculated cross sections for the reactions (n,γ), (n,n'), (n, 2n) and (n,p) as well as for (n,f) in 238 U are given. Comparisons with available experimental data are made and possible changes in the parameters are discussed. (Author) [pt

  14. Experimental determination of the antineutrino spectrum of the fission products of 238U

    International Nuclear Information System (INIS)

    Haag, Nils-Holger

    2013-01-01

    Fission of 238 U contributes about 10 % to the antineutrino emission of a pressurized water reactor. In the present thesis, the beta spectrum of the fission products of 238 U was determined in an experiment at the neutron source FRM II. This beta spectrum was subsequently converted into an antineutrino spectrum. This first measurement of the antineutrino spectrum supports all current and future reactor antineutrino experiments.

  15. Experimental determination of the antineutrino spectrum of the fission products of {sup 238}U

    Energy Technology Data Exchange (ETDEWEB)

    Haag, Nils-Holger

    2013-10-09

    Fission of {sup 238}U contributes about 10 % to the antineutrino emission of a pressurized water reactor. In the present thesis, the beta spectrum of the fission products of {sup 238}U was determined in an experiment at the neutron source FRM II. This beta spectrum was subsequently converted into an antineutrino spectrum. This first measurement of the antineutrino spectrum supports all current and future reactor antineutrino experiments.

  16. 238U and 237Np nuclear fission by 90-270 MeV electrons

    International Nuclear Information System (INIS)

    Kuznetsov, V.L.; Nedorezov, V.G.; Nikitina, N.V.; Noga, V.I.; Ranyuk, Yu.N.; Telegin, Yu.N.; Smirnov, A.N.; Ehjsmont, V.P.

    1981-01-01

    A technique for measuring cross sections of 238 U and 237 Np nuclei fission caused by 90-270 MeV electrons is described. Measurement results are given. The results obtained are discussed on the basis of the virtual photon method. It is shown that the difference in cross sections of 238 U and 237 Np electrofission is due to the different contribution of the giant resonance [ru

  17. Effect of 222Rn emanation from crystals on their 206Pb/238U age dating

    International Nuclear Information System (INIS)

    Barretto, Paulo M.C.

    2009-01-01

    The escape of radon from certain minerals with high uranium is of particular interest to those concerned with the determination of ages of rocks, minerals and tectonic events. To the extent that radon escapes, these minerals are not closed systems from the thermodynamic point of view and, more particularly, from the geochronological point of view. This investigation aimed to determine the radon escape from zircon crystals and how this fit into the severe isotopic constraints of the concordia dating model. To evaluate the consequences of radon loss on 238 U/ 206 Pb age dating methods, 20 zircon concentrates were analyzed. The observed range of relative percentage of radon loss was of 0.2-12 % and correlations with weathering of the crystals with natural alpha dose and with U-Pb age discordances were found. These correlations indicate relationships between the amount of lattice damage by radiation, the radon leakage out of the crystal and Pb mobility. Some of the stochastic complexities in specific age determinations are also discussed. (author)

  18. Probing the role of Skyrme interactions on the fission dynamics of the {sup 6}Li + {sup 238}U reaction

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ishita; Kumar, Raj; Sharma, Manoj K. [Thapar University, School of Physics and Materials Science, Patiala (India)

    2017-06-15

    The performance of selected five Skyrme forces (out of a set of 240), tested by Dutra et al., is analyzed in view of fusion-fission dynamics. These forces are assumed to perform better for neutron-rich systems, so the choice of the reaction is accordingly made by opting for a neutron-rich target in {sup 6}Li + {sup 238}U reaction. This reaction is diagnosed further in reference to fusion hindrance within the dynamical approach of the cluster-decay model (DCM). In order to reduce the computational time, three Skyrme forces are figured out with the criteria that these forces cover the barrier characteristics of the remaining two forces as well. The fission cross-sections are successfully addressed at low energies for the {sup 6}Li + {sup 238}U reaction. However, at relatively higher energies, the excitation functions show theoretical suppression with respect to experimental data, which may be associated with the possible existence of incomplete fusion (ICF). For ICF, we have considered that the {sup 6}Li broke into {sup 4}He + {sup 2}H, as mentioned in the experimental work. The calculations of ICF are carried out for the {sup 4}He + {sup 238}U reaction with the selected Skyrme forces at E{sub c.m.} = 26.20 and 27.51 MeV. These forces address the data nicely for the compound nucleus (CN) as well as ICF processes. Here, the NRAPR force seems to require lesser barrier modification as compared to the other forces, therefore it can be used as an alternate choice for calculating the interaction potential. Additionally, the prediction of cross-sections at lower energies has been done with DCM using the NRAPR force. The l-dependent % barrier modification of the Skyrme forces undertaken is also worked out in reference to fusion hindrance at below barrier energies. (orig.)

  19. Energy spectra of neutrons accompanying the emission fission of 238U

    International Nuclear Information System (INIS)

    Smirenkin, G.N.; Lovchikova, G.N.; Trufanov, A.M.; Svirin, M.I.; Polyakov, A.V.; Vinogradov, V.A.; Dmitriev, V.D.; Boykov, G.S.

    1996-01-01

    The spectra of fission neutrons emitted from 238U are measured for the first time by the time-of-flight method at incident-neutron energies of 16.0 and 17.7 MeV. Analysis of the neutron spectra shows that experimental results at incident-neutron energies of 14.7, 16.0, and 17.7 MeV (above the threshold of chance fission) differ significantly from those obtained at a neutron energy of 2.9 MeV (below the threshold of chance fission). Owing to the prefission emission of neutrons, the observed spectra of neutrons from emission fission exhibit a characteristic growth of the neutron yield in both hard and soft sections of the spectrum of secondary neutrons. This growth manifests itself as a step in the first case and as a rise in the second case, where it results in a noticeable excess of neutrons over the statistical-model predictions for E<2 MeV. The first feature in the spectra of neutrons from emission fission can be associated with the nonequilibrium decay of an excited fissile nucleus. On the contrary, the origin of the second feature has yet to be clarified. Additional measurements of angular distributions of secondary neutrons may prove helpful in this respect

  20. Determination of specific concentrations of {sup 40}K, {sup 238}U and {sup 232}Th in mineral fertilizer samples

    Energy Technology Data Exchange (ETDEWEB)

    Garcez, Ricardo W.D.; Lopes, Jose M.; Silva, Ademir X., E-mail: r.w.o.g@fisica.if.uff.br, E-mail: ademir@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Domingues, Alessandro M.; Lima, Marco F. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil)

    2015-07-01

    The use of fertilizer is an established practice worldwide to promote agricultural productivity increased without increasing the planted area, resulting in native forests protection and increase of the food availability. Some kinds of fertilizer have in their chemical composition some radionuclides due the origin of its feedstock, such as {sup 238}U, the {sup 232}Th, and their descendants, beyond {sup 40}K. Knowledge of the radioactivity levels in the environment is great importance to know the gamma radiation dose that the human being is exposed. For identification and quantitation of radionuclides, it was used gamma spectrometry where HPGe detector was used to obtain the spectra, and LabSOCS software for calculating the detection efficiency for each energy. The values of {sup 232}Th specific concentrations ranged from 4.1 to 368.1 Bq.Kg{sup -1}, the values of {sup 238}U specific concentrations ranged from 16.0 to 647.7 Bq.Kg{sup -1} and {sup 40}K specific concentrations ranged from 19.1 to 12713 Bq.Kg{sup -1}. Concentrations of values are consistent with those found in literature. (author)

  1. Assay of Uranium Isotopic Ratios 234U/238U, 235U/238U in Bottom Sediment Samples Using Destructive and Non Destructive Techniques (Nasser Lake)

    International Nuclear Information System (INIS)

    Agha, A.R.; El-Mongy, S.A.; Kandel, A.E.

    2011-01-01

    Nasser Lake is the greatest man-made lake in the World. It is considered as the main source of water where the Nile water is impounded behind the Aswan high dam.. Uranium has three naturally occurring isotopes 234 U, 235 U and 238 U with isotopic abundance 0.00548, 0.7200 and 99.2745 atom percent. Dissolved uranium in the lake is primary due to weathering process. Monitoring of the isotopic ratios of uranium is used as a good indicator to trace and evaluate the origin and activities associated with any variation of uranium in the lake environment. The main objective of the present study is to clarify any potential variation of natural uranium 234 U/ 238 U, 235 U/ 238 U ratios in sediment samples of Nasser Lake by using destructive alpha and non destructive gamma- techniques. The results show that the uranium isotopic activity ratios are very close to the natural values. This study can also be used for radiological protection and safety evaluation purposes.

  2. 230Th-238U disequilibrium and the melting processes beneath ridge axes

    International Nuclear Information System (INIS)

    McKenzie, D.

    1985-01-01

    The activity ratio ( 230 Th/ 238 U) is calculated for a simple model of melting, for which the melt fraction in chemical and radioactive equilibrium with the solid residium remains constant as melting proceeds. The activity ratio in the melt is only significantly different from unity if the melting is slow compared with the half-life of 230 Th and if the melt fraction present at any time does not exceed a few percent. The observation that ( 230 Th/ 238 U) is about 1.25 for many ocean ridge basalts is therefore most easily explained if the melt fraction in the source region is less than 2% and if the melting occurs in a broad region more than 100 km wide beneath the ridge axis. These results are compatible with other geophysical observations. Measurements of ( 226 Ra/ 238 U) might provide useful constraints on the time required to reach chemical equilibrium between the melt and the matrix. (orig.)

  3. Light nuclides observed in the fission and fragmentation of 238U

    International Nuclear Information System (INIS)

    Ricciardi, M.V.; Schmidt, K.H.; Benlliure, J.

    2001-05-01

    Light nuclides produced in collisions of 1 A.GeV 238 U with protons and titanium have been fully identified with a high-resolution forward magnetic spectrometer, the fragment separator (FRS), at GSI, and for each nuclide an extremely precise determination of the velocity has been performed. The so-obtained information on the velocity shows that the very asymmetric fission of uranium, in the 238 U + p reaction, produces neutron-rich isotopes of elements down to around charge 10. New important features of the fragmentation of 238 U, concerning the velocity and the N/Z-ratio of these light fragments, and a peculiar even-odd structure in N=Z nuclei, have also been observed. (orig.)

  4. Mass spectrometric 230Th-234U-238U dating of the Devils Hole calcite vein

    International Nuclear Information System (INIS)

    Ludwig, K.R.; Simmons, K.R.; Szabo, B.J.; Riggs, A.C.; Winograd, I.J.; Landwehr, J.M.; Hoffman, R.J.

    1992-01-01

    The Devils Hole calcite vein contains a long-term climatic record, but requires accurate chronologic control for its interpretation. Mass-spectrometric U-series ages for samples from core DH-11 yielding 230 Th ages with precisions ranging from less than 1,000 years (2σ) for samples younger than ∼140 ka (thousands of years ago) to less than 50,000 years for the oldest samples (∼566 ka). The 234 U/ 238 U ages could be determined to a precision of ∼20,000 years for all ages. Calcite accumulated continuously from 566 ka until ∼60 ka at an average rate of 0.7 millimeter per 10 3 years. The precise agreement between replicate analyses and the concordance of the 230 Th/ 238 U and 234 U/ 238 U ages for the oldest samples indicate that the DH-11 samples were closed systems and validate the dating technique in general

  5. Determination of the isotopic ratio {sup 234} U/{sup 238} U and {sup 235} U/{sup 238} U in uranium commercial reagents by alpha spectroscopy; Determinacion de la relacion isotopica {sup 234} U/{sup 238} U y {sup 235} U/{sup 238} U en reactivos comerciales de uranio por espectrometria alfa

    Energy Technology Data Exchange (ETDEWEB)

    Iturbe G, J L

    1990-02-15

    In this work the determination of the isotope ratio {sup 234} U/{sup 238} U and {sup 235} U/{sup 238} U obtained by means of the alpha spectroscopy technique in uranium reagents of commercial marks is presented. The analyzed uranium reagents were: UO{sub 2} (*) nuclear purity, UO{sub 3} (*) poly-science, metallic uranium, uranyl nitrate and uranyl acetate Merck, uranyl acetate and uranyl nitrate Baker, uranyl nitrate (*) of the Refinement and Conversion Department of the ININ, uranyl acetate (*) Medi-Lab Sigma of Mexico and uranyl nitrate Em Science. The obtained results show that the reagents that are suitable with asterisk (*) are in radioactive balance among the one {sup 234} U/{sup 238} U, since the obtained value went near to the unit. In the case of the isotope ratio {sup 235} U/{sup 238} U the near value was also obtained the one that marks the literature that is to say 0.04347, what indicates that these reagents contain the isotope of {sup 235} U in the percentage found in the nature of 0.71%. The other reagents are in radioactive imbalance among the {sup 234} U/{sup 238} U, the found values fluctuated between 0.4187 and 0.1677, and for the quotient of activities {sup 235} U/{sup 238} U its were of 0.0226, and the lowest of 0.01084. Also in these reagents it was at the {sup 236} U as impurity. The isotope of {sup 236} U is an isotope produced artificially, for what is supposed that the reagents that are in radioactive imbalance were synthesized starting from irradiated fuel. (Author)

  6. Sensitivity of 238U resonance absorption to library multigroup structure as calculated by WIMS-AECL

    International Nuclear Information System (INIS)

    Laughton, P.J.; Donnelly, J.V.

    1995-01-01

    In simulations of the TRX-1 experimental lattice, WIMS-AECL overpredicts, relative to MCNP, resonance absorption in neutron-energy groups containing the three large, low-lying resonances of 238 U when a standard ENDF/B-V-based library is used. A total excess in these groups of 4.0 neutron captures by 238 U per thousand fission neutrons has been observed. Similar comparisons are made in this work for the MIT-4 experimental lattice and simplified CANDU lattice cells containing 37-element fuel, with and without heavy-water coolant. Eleven different 89-group cross-section libraries were constructed for WIMS-AECL from ENDF/B-V data: only the neutron-energy-group boundaries used in generating multigroup cross sections and the Goldstein-Cohen correction factors differ from one library to the next. The first library uses the original 89-group structure, and the other ten involve energy groups of varying widths centred on the three large, low-lying resonances of 238 U. For TRX-1, some reduction in total discrepancy in 238 U capture can be achieved by using a new structure, although the improvement is small. The discrepancies in 238 U capture are of the same order for the MIT-4 case as those observed for TRX-1 for both the original group structure and the ten new structures. The WIMS-AECL calculation of 238 U resonance absorption in the same ranges of energy for the simplified CANDU 37-element lattice are in better agreement with MCNP than they are for TRX-1 and MIT-4: when the original structure is used, WIMS-AECL underpredicts total capture rate by 238 U in the energy range of interest by only 0.56 per thousand fission neutrons (coolant present) and 0.88 per thousand fission neutrons (voided coolant channel). The discrepancies are reduced when some of the new structures are used. For almost all of the cases considered here-TRX-1, MIT-4 and CANDU with coolant-better group-by-group agreement of 238 U capture around the 6.67-eV resonance is achieved by using a new library

  7. 222Rn content and 234U/238U activity ratio in groundwaters

    International Nuclear Information System (INIS)

    Olguin, M.T.; Segovia, N.; Ordonez, E.; Iturbe, J.L.; Bulbulian, S.; Carrillo, J.

    1990-01-01

    Geochemical radioanalytical studies of ground water were perfomed in the valleys of Villa de Reyes and San Luis Potosi, Mexico. The experiments were designed to measure radon and uranium content and 234 U/ 238 U activity ratio in ground water samples taken from wells in these sites and at the Nuclear Center of Salazar, Mexico. 222 Rn content varied depending on the sample source, reaching a maximum value of 235 pCi/l; uranium concentration results were less than 1 μg/l and 234 U/ 238 U activity ratios were close to equilibrium. (author) 9 refs.; 1 fig.; 1 tab

  8. 238 U 92 radionuclide handbook. Natural Uranium and environment

    International Nuclear Information System (INIS)

    Garnier-Laplace, J.; Colle, C.; Morello, M.

    2001-01-01

    This handbook summarizes the behaviour of the chemical element in the main compartments of land and aquatic ecosystems, under the two following assumptions: isotopic discrimination is negligible (this is validated for most of the examined elements); when the element possesses stable isotopes, the behaviour analogy between its stable and radioactive isotopes is implicitly admitted, knowing that, for elements existing at the natural state, the chemical form and the emitting media of the anthropic effluents are susceptible of implying other transfer processes than those identified for the natural stable element. The handbook gives information on the chemical and nuclear characteristics of the element, its origins, the concentrations in the environment, the mobility and bio-availability in land ecosystems (soils, plants, animals) and aquatic ecosystems (waters, sediments, plants, animals)

  9. 238U (n,f) measurements below 30 keV

    International Nuclear Information System (INIS)

    Slovacek, R.E.; Cramer, D.S.; Bean, E.B.; Hockenbury, R.W.; Valentine, J.R.; Block, R.C.

    1975-01-01

    The 238 U (n,f) cross section has been measured from 3 eV to about 30 keV with the lead slowing down spectrometer at the RPI Linac. Four fission ionization chambers containing a total of about 0.8 gm of 238 U (4.1 ppm 235 U) were used for the measurements. The fission widths of the 6.67, 20.9, and the 36.8 eV resonances were measured as (10 +- 1), (58 +- 9), and (12 +- 2) nanoelectron-volts respectively. The fission cross section integrated over the two subthreshold groups at 720 and 1210 eV and the average fission cross section from 10 to 30 keV are in agreement with a previous time of flight measurement. The fission width at 6.67 eV is 20 times smaller than an upper limit set by the only reported measurement in this energy region; the fission widths obtained in the present investigation are consistent with the (30 +- 50) nanoelectronvolt average width previously obtained for the resonances between 37 and 327 eV in a time of flight measurement using a nuclear device. From the measured fission widths, the 238 U thermal fission cross section was determined to be 2.7 +- 0.3 μ barns. The resonance fission integral was also obtained from the data as 1.33 +- 0.15 mbarns for 238 U. (4 figures, 4 tables) (U.S.)

  10. Two types of adakites revealed by 238U-230Th disequilibrium from Daisen volcano, southwestern Japan

    International Nuclear Information System (INIS)

    Tokunaga, Saimi; Nakai, Shun'ichi; Orihashi, Yuji

    2010-01-01

    Daisen volcano is located on the Quaternary volcanic front in southwestern Japan. The volcano is composed mainly of andesite and dacite, which chemically resemble adakites, with high Al 2 O 3 and Sr/Y, steep REE patterns, and no negative Eu anomaly. ( 238 U/ 230 Th) disequilibrium (herein, a ratio in parentheses denotes the activity ratio) and trace element analyses of adakites from two volcanic domes, Karasugasen and Misen, indicate two adakite types. Adakite from Karasugasen is characterized by excess ( 230 Th) over ( 238 U), typical of most adakites, whereas adakite from Misen is characterized by excess ( 238 U) over ( 230 Th). The latter is consistent with enrichment in fluid-mobile elements relative to fluid immobile elements compared to rocks from Karasugasen. The values of ( 230 Th/ 232 Th) of adakites from Karasugasen and Misen are, respectively, around 0.75 and 0.81. These low ( 230 Th/ 232 Th) ratios result from the incorporation of subducted sedimentary material. The ratios, nevertheless, are higher than that for the estimate of lower crustal material suggesting significant incorporation of lower crust is unlikely. As adakites from Misen have ( 238 U) excess over ( 230 Th), adakite magma must have interacted with wedge mantle metasomatized by a slab-derived fluid, confirming the presence of a fluid-metasomatized mantle beneath Daisen volcano. (author)

  11. Isotope shift of 234U, 236U, 238U in U I

    International Nuclear Information System (INIS)

    Gagne, J.M.; Nguyen Van, S.; Saint-Dizier, J.P.; Pianarosa, P.

    1976-01-01

    New and very accurate data of isotope shifts and relative isotope shifts in 234 U, 236 U, 238 U are presented. The invariance of the relative isotope shift, for the transitions we have investigated, supports the hypothesis that the so called specific mass effect is negligible in uranium

  12. Energy distribution of neutrons from the (n,2n) reaction in 238U

    International Nuclear Information System (INIS)

    Misulovin, A.

    1978-12-01

    Energy distribution of the first and second neutrons from (n,2n) scattering event in 238 U was evaluated according to the consistent compound nucleus model recently proposed by Segev. The law for deriving the energy distribution of secondary neutrons from a (n,2n) scattering event, depends on whether the reaction is considered as a simultaneous emission of two neutrons from one compound nucleus, or a successive emission of neutrons from different compound nuclei. Segev has presented a means of calculating the energy distribution assuming the latter model. The laws presented in the ENDF/B data files suggest the former model. The evaluation was based on inelastic level excitation and evaporation data for 238 U and 237 U. Data was retrieved from ENDF/B files. The evaporation data for 237 U was based on (γ,n) reaction 238 U. The inelastic level excitation data for 237 U was evaluated at the Soreq Nuclear Research Centre. It is concluded from the application of Segev's model to 238 U, that the energetic spectrum of secondary neutrons, is harder in the high range of energy than the one predicted by the use of the distribution law presented in ENDF/B data files. The spectrum of secondary (n,2n) neutrons, resulting from the interaction of 14 MeV neutrons in 238 U calculated with Segev's model, is compared with the corresponding spectrum of the LLL library, ENDF/B library and the recent evaluation of BNWL. It is found that the spectrum evaluated by LLL and BNWL is harder than that evaluated with Segev's model

  13. 238U, and its decay products, in grasses from an abandoned uranium mine

    Science.gov (United States)

    Childs, Edgar; Maskall, John; Millward, Geoffrey

    2016-04-01

    Bioaccumulation of radioactive contaminants by plants is of concern particularly where the sward is an essential part of the diet of ruminants. The abandoned South Terras uranium mine, south west England, had primary deposits of uraninite (UO2) and pitchblende (U3O8), which contained up to 30% uranium. When the mine was active uranium and radium were extracted but following closure it was abandoned without remediation. Waste rock and gangue, consisting of inefficiently processed minerals, were spread around the site, including a field where ruminants are grazed. Here we report the activity concentrations of 238U, 235U 214,210Pb, and the concentrations of selected metals in the soils, roots and leaves of grasses taken from the contaminated field. Soil samples were collected at the surface, and at 30 cm depth, using an auger along a 10-point transect in the field from the foot of a waste heap. Whole, individual grass plants were removed with a spade, ensuring that their roots were intact. The soils and roots and grass leaves were freeze-dried. Activity concentrations of the radionuclides were determined by gamma spectroscopy, following 30 days incubation for development of secular equilibrium. Dried soils, roots and grasses were also digested in aqua regia and the concentrations of elements determined by ICP techniques. Maximum activity concentrations of 238U, 235U, 214Pb and 210Pb surface soils were 63,300, 4,510, 23,300 and 49,400 Bq kg-1, respectively. The mean 238U:235U ratio was 11.8 ± 1.8, an order of magnitude lower than the natural value of 138, indicating disequilibrium within the decay chain due to mineral processing. Radionuclides in the roots had 5 times lower concentration and only grass leaves in the vicinity of the waste heap had measureable values. The mean soil to root transfer factor for 238U was 36%, the mean root to leaf was 3% and overall only 0.7% of 238U was transferred from the soil to the leaves. The roots contained 0.8% iron, possibly as

  14. Measurement and resonance analysis of neutron transmissions through four samples of 238U

    International Nuclear Information System (INIS)

    Olsen, D.K.; de Saussure, G.; Perez, R.B.; Difilippo, F.C.; Ingle, R.W.

    1977-01-01

    Accurate total and partial cross sections for 238 U are important for nuclear reactor design. In the resolved resonance region, energies below 4.0 keV, these cross sections are described in terms of individual resonance parameters of which the neutron widths in the 1.5 to 4.0 keV region from various workers appear discrepant. In order to determine these widths, (0.880 to 100.0 keV) neutron transmissions through 0.076, 0.254, 1.080, and 3.620 cm thick enriched 238 U samples were measured, and (0.880 to 100.0 keV) range transmissions were analyzed

  15. The Effect of Early Diagenesis on the 238U/235U Ratio of Platform Carbonates.

    Science.gov (United States)

    Tissot, F.; Chen, C.; Go, B. M.; Naziemiec, M.; Healy, G.; Swart, P. K.; Dauphas, N.

    2017-12-01

    In the past 15 years, the so-called non-traditional stable isotopes systems (e.g., Mg, Fe, Mo, U) have emerged as powerful tracers of both high-T and low-T geochemical processes (e.g., [1]). Of particular interest for paleoredox studies is the ratio of "stable" isotopes of U (238U/235U), which has the potential to track the global extent of oceanic anoxia (e.g., [2, 3]). Indeed, in the modern ocean, U exists in two main oxidation states, soluble U6+ and insoluble U4+, and has a mean residence time of 400 kyr ([4]), much longer than the global ocean mixing time (1-2 kyr). As such the salinity-normalized ocean is homogeneous with regards to both U concentrations and isotopes (δ238USW = -0.392±0.005 ‰, [2]). The value of δ238USW at any given time is therefore the balance between U input to the ocean, mainly from rivers, and U removal, mostly into biogenic carbonates, anoxic/euxinic sediments and suboxic/hypoxic sediments (e.g., [2, 5]). Because the 238U/235U ratio of the past ocean cannot be measured directly, it has to be estimated from the measurement of the 238U/235U ratio of a sedimentary rock and assuming a constant fractionation factor. Carbonates appear as a promising record since they span most of Earth's history, and the δ238U values of modern primary carbonate precipitates and well-preserved fossil aragonitic coral up to 600 ka are indistinguishable from that of seawater (e.g., [2, 6, 7]). Yet, the effect of secondary processes on the δ238U values of non-coral carbonates, which represent the bulk of the rock record, has only been studied in a handful of shallow samples (down to 40cm, [6]) and remains poorly understood. To investigate the effect of early diagenesis on the 238U/235U ratio of carbonates on the 30kyr to 1Myr timescale, we measured δ13C, δ18O, and δ238U in samples from a 220m long drill core from the Bahamas carbonate platform. In order to separate lattice bound U from secondary U we developed a leaching protocol applicable to carbonate

  16. 235U and 238U (n,xn gamma) cross-sections

    International Nuclear Information System (INIS)

    Bacquias, A.; Dessagne, Ph.; Kerveno, M.; Rudolf, G.; Thiry, J.C.; Borcea, C.; Negret, A.L.; Drohe, J.C.; Nankov, N.; Nyman, M.; Plompen, A.; Rouki, C.; Stanoiu, M.

    2014-01-01

    The (n,n') and (n,2n) are important processes in the energy domain of fission neutrons, but the cross-sections suffer from large uncertainties, not compatible with the objectives fixed for future and advanced nuclear reactors. This paper presents our experimental effort to improve 235 U and 238 U (n,xnγ) cross-section data. The experiments were performed at the GELINA facility (Belgium), which provides a pulsed (800 Hz) neutron beam covering a wide energy spectrum (from a few eV to about 20 MeV). The GRAPhEME set-up is designed for prompt gamma spectroscopy and time-of-flight measurement. The analysis methods are presented. Already published results on 235 U are shown, as well as results on 238 U. The interpretation and discussion rely on the comparison with TALYS and EMPIRE predictions. (authors)

  17. Nonradiative excitation of the muonic atom 238U as an inverse conversion process

    International Nuclear Information System (INIS)

    Karpeshin, F.F.; Nesterenko, V.U.

    1982-01-01

    The probabilities of nonradiation nuclear excitation are calculated for different muon transitions in the muonic atom 238 U. Microscopic nuclear wave functions, obtained within the quasiparticle-phonon nuclear model and the muonic conversion coefficients have been used. The probability of nonradiation nuclear excitation for the muonic transitions 2p → 1s and 3p → 1s has been found to be equal to 0.3. It is predicted that nonradiative E3 transitions 3d → 2p can take place with the probability 0.08-0.10. The dynamic effect of nuclear structure on the probability of nonradiative nuclear excitation is taken into account. The estimates of 238 U fissility fission branching at nonradiation transitions are also obtained

  18. Uranium 234U and 238U isotopes in the southern Baltic environment

    International Nuclear Information System (INIS)

    Borylo, A.; Skwarzec, B.

    2002-01-01

    The concentration and distribution of uranium in water and sediment of selected basins of the southern Baltic Sea have been analysed. It was observed that the concentration of uranium in sediments increases with core depth. This is probably connected to diffusion processes from sediments to water through interstitial water where uranium concentration is much higher than in bottom water. The measurements of 234 U/ 238 U activity ratios indicate that sedimentation of terrigenic material and transport through Vistula river are the major sources of uranium in sediments of the southern Baltic Sea. Estimation of the 234 U/ 238 U ratios in reduction areas of the Baltic Deep and the Bornholm Deep suggest that the processes of reduction of U(VI) to U(IV) and of removal of authogenic uranium from seawater to sediments do not play major roles in the Gdansk Deep. (author)

  19. Sensitivity coefficients for the 238U neutron-capture shielded-group cross sections

    International Nuclear Information System (INIS)

    Munoz-Cobos, J.L.; de Saussure, G.; Perez, R.B.

    1981-01-01

    In the unresolved resonance region cross sections are represented with statistical resonance parameters. The average values of these parameters are chosen in order to fit evaluated infinitely dilute group cross sections. The sensitivity of the shielded group cross sections to the choice of mean resonance data has recently been investigated for the case of 235 U and 239 Pu by Ganesan and by Antsipov et al; similar sensitivity studies for 238 U are reported

  20. A study of the differential cross section in subbarrier photofission of 238U

    International Nuclear Information System (INIS)

    Lindgren, L.J.; Sandell, A.

    1977-03-01

    A measurement of the angular distribution and yield of fission fragments from photofission of 238 U has been performed between 5.2 MeV and 6.4 MeV. As γ-source the bremsstrahlung from a microtron has been used. For the detection of the fission fragments solid state track detectors were used. The yield data were evaluated to approximate cross sections. The data were analyzed within the framework of the double hump barrier model. (Auth.)

  1. Evidence for contamination of recent Hawaiian lavas from 230Th-238U data

    International Nuclear Information System (INIS)

    Condomines, M.; Bernat, M.; Allegre, C.J.

    1976-01-01

    230 Th- 238 U radioactive disequilibrium was studied in the historical lava flows of the Mauna Loa and Kilauea, Hawaii. Large variations of the ( 230 Th/ 232 Th) ratio among lavas of the same volcano that were erupted at a few years' interval are interpreted as due to contamination. The contamination probably occurs by assimilation of zeolitic minerals formed by seawater interaction while the magma resides in a superficial chamber. (Auth.)

  2. Benchmark calculations on resonance absorption by 238U in a PWR pin-cell geometry

    International Nuclear Information System (INIS)

    Kruijf, W.J.M. de; Janssen, A.J.

    1993-12-01

    Very accurate Monte Carlo calculations with MCNP have been performed to serve as a reference for benchmark calculations on resonance absorption by 238 U in a typical PWR pin-cell geometry. Calculations with the energy-pointwise slowing down code ROLAIDS-CPM show that this code calculates the resonance absorption accurately. Calculations with the multigroup discrete ordinates code XSDRN show that accurate results can only be achieved with a very fine energy mesh. (orig.)

  3. Measurement of neutron inelastic scattering cross section of {sup 238}U

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Takako; Baba, Mamoru; Ibaraki, Masanobu; Sanami, Toshiya; Win, Than; Hirasawa, Yoshitaka; Matsuyama, Shigeo; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan)

    1998-03-01

    Neutron scattering from the 0{sup +}, 2{sup +} (1-st) and 4{sup +} (2nd) levels of {sup 238}U was measured for incident energies between 0.4 and 0.85 MeV at the Tohoku University 4.5 MV Dynamitron facility, using the time-of-flight (TOF) method with monoenergetic pulsed neutrons by the {sup 7}Li(p,n) reaction. The results are presented in comparison with other experimental data and evaluated data. (author)

  4. 234Th/238U disequilibrium in near-shore sediment: particle reworking and diagenetic time scales

    International Nuclear Information System (INIS)

    Aller, R.C.; Cochran, J.K.

    1976-01-01

    The distribution of 234 Th (tsub(1.2)=24.1 days) in excess of its parent 238 U in the upper layers of near-shore sediment makes possible the evaluation of short-term sediment reworking and diagenetic rates. 234 Th has a maximum residence time in Long Island Sound water of 1.4 days. Seasonal measurement of 234 Th/ 238 U disequilibrium in sediment at a single station in central Long Island Sound demonstrates rapid particle reworking and high 234 Thsub(XS)(>1 dpm/g) in the upper 4 cm of sediment with slower, irregular reworking and low 234 Thsub(XS) to at least 12 cm. The rate of rapid particle reworking varies seasonally and is highest in the fall. The rapidly mixed zone is characterized by steep gradients in sediment chemistry implying fast reactions spanned by 234 Th decay time scales. 238 U is depleted in the upper mixed zone and shows addition in reducing sediment at depth. (Auth.)

  5. Uranium contents and 234U/238U activity ratios of modern and fossil marine bivalle molluscan shells

    International Nuclear Information System (INIS)

    Mitsuda, Hiroshi

    1984-01-01

    Uranium contents and 234 U/ 238 U activity ratios in modern and fossil marine bivalle molluscan shells were measured by alpha-spectrometry. Uranium contents and 234 U/ 238 U activity ratios in modern shells were averaged to be 0.266 (dpm/g), and 1.18, respectively and those in fossil shells were averaged to be 0.747 (dpm/g), and 1.19, respectivily. Uranium contents in fossil shells were obviously higher than those in modern shells. It can be explained by the addition of uranium to shell during the deposition. In fossil shells, 234 U/ 238 U activity ratio decreases as 238 U content increases the same tendency is not found in modern shells. The author proposed a mechanism of selective loss of 238 U from the fossil shells for the explanation of this tendency. The height activity ratio of 234 U/ 238 U measured on the fossil shells than that measured on the modern shells, also support the selective loss of 238 U from the fossil shells. (author)

  6. Solubility of 238U radionuclide from various types of soil in synthetic gastrointestinal fluids using "US in vitro" digestion method

    Science.gov (United States)

    Rashid, Nur Shahidah Abdul; Sarmani, Sukiman; Majid, Amran Ab.; Mohamed, Faizal; Siong, Khoo Kok

    2015-04-01

    238U radionuclide is a naturally occuring radioactive material that can be found in soil. In this study, the solubility of 238U radionuclide obtained from various types of soil in synthetic gastrointestinal fluids was analysed by "US P in vitro" digestion method. The synthetic gastrointestinal fluids were added to the samples with well-ordered, mixed throughly and incubated according to the human physiology digestive system. The concentration of 238U radionuclide in the solutions extracted from the soil was measured using Induced Coupling Plasma Mass Spectrometer (ICP-MS). The concentration of 238U radionuclide from the soil samples in synthetic gastrointestinal fluids showed different values due to different homogenity of soil types and chemical reaction of 238U radionuclide. In general, the solubility of 238U radionuclide in gastric fluid was higher (0.050 - 0.209 ppm) than gastrointestinal fluids (0.024 - 0.050 ppm). It could be concluded that the US P in vitro digestion method is practicle for estimating the solubility of 238U radionuclide from soil materials and could be useful for monitoring and risk assessment purposes applying to environmental, health and contaminated soil samples.

  7. The estuarine chemistry and isotope systematics of 234,238U in the Amazon and Fly Rivers

    Science.gov (United States)

    Swarzenski, P.; Campbell, P.; Porcelli, D.; McKee, B.

    2004-01-01

    complexation reactions. In the Fly River estuary, 238U appears to exhibit a reasonably conservative distribution as a function of salinity. The absence of observed U removal does not necessarily imply non-reactivity, but instead may record an integration of concurrent U removal and release processes. There is not a linear correlation between ??234U vs. 1/ 238U that would imply simple two component mixing. It is likely that resuspension of bottom sediments, prolonged residence times in the lower reaches of the Fly River, and energetic particle-colloid interactions contribute to the observed estuarine U distribution. The supply of uranium discharged from humid, tropical river systems to the sea appears to be foremost influenced by particle/water interactions that are ultimately governed by the particular physiographic and hydrologic characteristics of an estuary. ?? 2004 Elsevier Ltd. All rights reserved.

  8. The estuarine chemistry and isotope systematics of 234,238U in the Amazon and Fly Rivers

    Science.gov (United States)

    Swarzenski, Peter; Campbell, Pamela; Porcelli, Don; McKee, Brent

    2004-12-01

    complexation reactions. In the Fly River estuary, 238U appears to exhibit a reasonably conservative distribution as a function of salinity. The absence of observed U removal does not necessarily imply non-reactivity, but instead may record an integration of concurrent U removal and release processes. There is not a linear correlation between δ234U vs. 1/238U that would imply simple two component mixing. It is likely that resuspension of bottom sediments, prolonged residence times in the lower reaches of the Fly River, and energetic particle-colloid interactions contribute to the observed estuarine U distribution. The supply of uranium discharged from humid, tropical river systems to the sea appears to be foremost influenced by particle/water interactions that are ultimately governed by the particular physiographic and hydrologic characteristics of an estuary.

  9. High energy resolution measurement of the sup 238 U neutron capture yield from 1 to 100 keV

    Energy Technology Data Exchange (ETDEWEB)

    Macklin, R.L. (Tennessee Univ., Knoxville, TN (United States). Dept. of Nuclear Engineering); Perez, R.B. (Tennessee Univ., Knoxville, TN (United States). Dept. of Nuclear Engineering Oak Ridge National Lab., TN (United States)); De Saussure, G.; Ingle, R.W. (Oak Ridge National Lab., TN (United States))

    1991-01-01

    The purpose of this work is the precise determination of the {sup 238}U neutron capture yield (i.e. the probability of neutron capture) as a function of neutron energy with the highest available neutron energy resolution. The motivation for this undertaking arises from the central role played by the {sup 238}U neutron capture process in the neutron balance of both thermal reactors and fast breeder reactors. The present measurement was performed using the Oak Ridge Electron Linear Accelerator (ORELA) facility. The pulsed beam of neutrons from the ORELA facility is collimated on a sample of {sup 238}U. The neutron capture rate in the sample is measured, as a function of neutron time-of-flight (TOF) by detecting the {gamma}-rays from the {sup 238}U(n, {gamma}){sup 239}U reaction with a large {gamma}-ray detector surrounding the {sup 238}U sample. At each energy, the capture yield is proportional to the observed capture rate divided by the measured intensity of the neutron beam. The constant of proportionality (the normalization constant) is obtained from the ratio of theoretical to experimentally measured areas under small {sup 238}U resonances where the resonance parameters have been determined from high-resolution {sup 238}U transmission measurements. The cross section for the reaction {sup 238}U(n,{gamma}){sup 239}U can be derived from the measured capture yield if one applies appropriate corrections for multiple scattering and resonance self-shielding. Some 200 {sup 238}U neutron resonances in the energy range from 250 eV to 10 keV have been observed which had not been detected in previous measurements. (author).

  10. The inflow of 234U and 238U from the River Odra drainage basin to the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Bogdan Skwarzec

    2010-12-01

    Full Text Available In this study the activity of uranium isotopes 234U and 238U in Odra river water samples, collected from October 2003 to July2004, was measured using alpha spectrometry. The uranium concentrations were different in each of the seasons analysed; the lowest values were recorded in summer. In all seasons, uranium concentrations were the highest in Bystrzyca river waters (from 27.81 ± 0.29Bq m-3 of 234U and 17.82 ± 0.23 Bq m-3 of 238U in spring to 194.76 ± 3.43 Bq m-3 of 234U and 134.88 ± 2.85 Bq m-3 of 238U in summer. The lowest concentrations were noted in the Mała Panew (from 1.33 ± 0.02 Bq m-3 of 234U and 1.06 ± 0.02 Bq m-3 of 238U in spring to 3.52 ± 0.05 Bq m-3 of 234U and 2.59± 0.04 Bq m-3 of 238U in autumn. The uranium radionuclides 234U and 238U in the water samples were not in radioactive equilibrium. The 234U / 238U activity ratios were the highest in Odra water samples collected at Głogów (1.84 in autumn, and the lowest in water from the Noteć (1.03 in winter and spring. The 234U / 238U activity ratio decreases along the main stream of the Odra, owing to changes in the salinity of the river's waters. Annually, 8.19 tons of uranium (126.29 G Bq of 234U and 100.80 G Bq of 238U flow into the Szczecin Lagoon with Odra river waters.

  11. IAEA CIELO Evaluation of Neutron-induced Reactions on 235U and 238U Targets

    Science.gov (United States)

    Capote, R.; Trkov, A.; Sin, M.; Pigni, M. T.; Pronyaev, V. G.; Balibrea, J.; Bernard, D.; Cano-Ott, D.; Danon, Y.; Daskalakis, A.; Goričanec, T.; Herman, M. W.; Kiedrowski, B.; Kopecky, S.; Mendoza, E.; Neudecker, D.; Leal, L.; Noguere, G.; Schillebeeckx, P.; Sirakov, I.; Soukhovitskii, E. S.; Stetcu, I.; Talou, P.

    2018-02-01

    Evaluations of nuclear reaction data for the major uranium isotopes 238U and 235U were performed within the scope of the CIELO Project on the initiative of the OECD/NEA Data Bank under Working Party on Evaluation Co-operation (WPEC) Subgroup 40 coordinated by the IAEA Nuclear Data Section. Both the mean values and covariances are evaluated from 10-5 eV up to 30 MeV. The resonance parameters of 238U and 235U were re-evaluated with the addition of newly available data to the existing experimental database. The evaluations in the fast neutron range are based on nuclear model calculations with the code EMPIRE-3.2 Malta above the resonance range up to 30 MeV. 235U(n,f), 238U(n,f), and 238U(n,γ) cross sections and 235U(nth,f) prompt fission neutron spectrum (PFNS) were evaluated within the Neutron Standards project and are representative of the experimental state-of-the-art measurements. The Standards cross sections were matched in model calculations as closely as possible to guarantee a good predictive power for cross sections of competing neutron scattering channels. 235U(n,γ) cross section includes fluctuations observed in recent experiments. 235U(n,f) PFNS for incident neutron energies from 500 keV to 20 MeV were measured at Los Alamos Chi-Nu facility and re-evaluated using all available experimental data. While respecting the measured differential data, several compensating errors in previous evaluations were identified and removed so that the performance in integral benchmarks was restored or improved. Covariance matrices for 235U and 238U cross sections, angular distributions, spectra and neutron multiplicities were evaluated using the GANDR system that combines experimental data with model uncertainties. Unrecognized systematic uncertainties were considered in the uncertainty quantification for fission and capture cross sections above the thermal range, and for neutron multiplicities. Evaluated files were extensively benchmarked to ensure good performance in

  12. Characteristics of synchrotron radiation

    International Nuclear Information System (INIS)

    Brown, G.S.

    1984-01-01

    The characteristics and production of synchrotron radiation are qualitatively discussed. The spectral properties of wigglers and undulators are briefly described. Possible applications in condensed matter physics are outlined. These include atomic and molecular studies, crystallography, impurities in solids and radiographic imaging

  13. Determination of sup 238 U in marine organisms by inductively coupled plasma mass spectrometry. Yudo ketsugo plasma shitsuryo bunsekiho ni yoru kaiyo seibutsuchu no sup 238 U no teiryo

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, T.; Nakahara, M; Matsuda, M.; Ishikawa, M. (National Institute of Radiological Sciences, Ibaraki (Japan))

    1991-05-25

    Since the {sup 238} U concentration in seawater is about 3ng/ml at the element level and the activity concentration is 40 {mu} Bq/ml which are considerably higher that those of other {alpha} radioactive materials, it is necessary to study the concentration levels of many marine organisms. After confirming that the inductively coupled plasma mass spectrometry as a new high sensitive analysis for multi-elements is effective to analyze heavy elements such as rare earth elements or uranium, etc., this method was applied to determine {sup 238} U in 55 species of marine organism. The {sup 238} U concentration in soft tissues of marine animal ranged from 0.076 to 5000ng/g wet weight and large difference of concentration was observed depending on the kind of animal and the tissue. Especially, the branchial heart of cephalopod molluscs showed the specific accumulation of {sup 238} U. The concentration factor of branchial heart of Octopus vulgaris which showed the highest value was calculated to be about 10 {sup 3} by comparing it with the concentration of {sup 238} U in Japanese coastal waterseas. The concentration of {sup 238} U in 20 species of algae ranged from 10 to 3700ng/g dry weight. 11 refs., 2 figs., 9 tabs.

  14. (e,e'f) coincidence experiments for fission decay of giant resonances in 235,238U

    International Nuclear Information System (INIS)

    Weber, T.; Heil, R.D.; Kneissl, U.; Pecho, W.; Wilke, W.; Emrich, H.J.; Kihm, T.; Knoepfle, K.T.

    1988-01-01

    Extending previous work on 238 U, 235 U(e,e'f) coincidence data were taken at 4 momentum transfers yielding both E1, E2/E0 and E3 form factors and the respective multipole strength distributions in the giant resonance region of 238 U (4 x x /Γ a is obtained as a function of excitation energy for separated multipoles. The giant E2 resonance exhibits an increased symmetric fission contribution compared to E1 and E3 resonances. (orig.)

  15. Neutron inelastic-scattering cross sections of 232Th, 233U, 235U, 238U, 239Pu and 240Pu

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.

    1982-01-01

    Differential-neutron-emission cross sections of 232 Th, 233 U, 235 U, 238 U, 239 Pu and 240 Pu are measured between approx. = 1.0 and 3.5 MeV with the angle and magnitude detail needed to provide angle-integrated emission cross sections to approx. 232 Th, 233 U, 235 U and 238 U inelastic-scattering values, poor agreement is observed for 240 Pu, and a serious discrepancy exists in the case of 239 Pu

  16. Radioactivity levels of 238U and 232Th, the α and β activities and associated dose rates from surface soil in Ulu Tiram, Malaysia

    International Nuclear Information System (INIS)

    Abdul Rahman, A.T.; Ramli, A.T.

    2007-01-01

    A survey was carried out to determine terrestrial gamma radiation dose rates, the concentration level of 238 U and 232 Th and α and β activities for the surface soil in Ulu Tiram, Malaysia. A 125 measurements were performed using a NaI(Tl) gamma-ray detector with crystal size of 1' x 1' on 15 soil samples collected from the site area about 102 km 2 . 238 U and 232 Th concentrations were determined in soils by using hyper pure germanium (HPGe) gamma-ray spectrometry. The activity of α and β from the surface soil was counted by using alpha beta counting system. The average value of 238 U and 232 Th concentrations in soil samples collected are 3.63±0.39 ppm within the range of 1.74±0.20 to 4.58±0.48 and 43.00±2.31 ppm within the range of 10.68±0.76 to 82.10±4.01 ppm, respectively. The average estimate of α and β activity in soil samples collected are 0.65±0.09 Bq x g -1 and 0.68±0.08 Bq x g -1 , respectively. The average of terrestrial gamma-radiation dose rates measured in Ulu Tiram was found to be 200 nGy x h -1 , within the range of 96 to 409 nGy x h -1 . The population weighted outdoor annual effective dose was 1.2 mSv. (author)

  17. Studies on 232Th and 238U levels in marine algae collected from the coast of Niigata Prefecture

    International Nuclear Information System (INIS)

    Kato, Kenji; Tonouchi, Shigemasa; Maruta, Fumiyuki; Ebata, Hidekazu

    2001-01-01

    To evaluate the properties of algae to concentrate radioactive elements, 14 species of algae like Sargassum were collected in the Prefecture and analyzed for their 232 Th and 238 U levels with Yokogawa HP4500 ICP-MS apparatus. The places of collection included those near the water discharge of an atomic power station. Mean 232 Th and 238 U levels were found to be 120 and 260 ng/g dry wt, respectively, and Phaeophyta showed more than several times higher 238 U level than Chlorophyta and Rhodophyta. There was no clear difference in 232 Th levels. No difference between places of collection was observed in Sargassum 232 Th or 238 U level. Adsorption of 232 Th particle to and incorporation of soluble 238 U into algae body were suggested. Mean 232 Th and 238 U radioactivities were found 73 and 510 μBq/g wet wt, respectively, and the respective annual committed effective doses, 0.2 and 0.3 μSv, calculated from those values were confirmed to be enough lower than the annual public dose limit, 1 mSv. (K.H.)

  18. Investigate the capability of INAA absolute method to determine the concentrations of 238U and 232Th in rock samples

    International Nuclear Information System (INIS)

    Alnour, I.A.

    2014-01-01

    This work aimed to study the capability of INAA absolute method in determining the elemental concentration of 238 U and 232 Th in the rock samples. The INAA absolute method was implemented in PUSPATI TRIGA Mark II research reactor, Malaysian Nuclear Agency (NM). The accuracy of INAA absolute method was performed by analyzing the IAEA certified reference material (CRM) Soil-7. The analytical results showed the deviations between experimental and certified values were mostly less than 10 % with Z-score in most cases less than 1. In general, the results of analysed CRM Soil-7 show a good agreement between certified and experimental results which mean that the INAA absolute method can be used accurately for elemental analysis of uranium and thorium in various types of samples. The concentration of 238 U and 232 Th ranged from 1.77 to 24.25 and 0.88 to 95.50 ppm respectively. The highest value of 238 U and 232 Th was recorded for granite rock sample G17 of 238 U and sample G9 of 232 Th, whereas the lower value was 1.77 ppm of 238 U recorded in sandstone rock and 0.88 ppm of 232 Th for gabbro. Moreover, a comparison of the 238 U and 232 Th results obtained by the INAA absolute method shows an acceptable level of consistency with those obtained by the INAA relative method. (author)

  19. Studies on {sup 232}Th and {sup 238}U levels in marine algae collected from the coast of Niigata Prefecture

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Kenji; Tonouchi, Shigemasa; Maruta, Fumiyuki; Ebata, Hidekazu [Niigata Prefectural Inst. of Public Health and Environmental Sciences (Japan)

    2001-12-01

    To evaluate the properties of algae to concentrate radioactive elements, 14 species of algae like Sargassum were collected in the Prefecture and analyzed for their {sup 232}Th and {sup 238}U levels with Yokogawa HP4500 ICP-MS apparatus. The places of collection included those near the water discharge of an atomic power station. Mean {sup 232}Th and {sup 238}U levels were found to be 120 and 260 ng/g dry wt, respectively, and Phaeophyta showed more than several times higher {sup 238}U level than Chlorophyta and Rhodophyta. There was no clear difference in {sup 232}Th levels. No difference between places of collection was observed in Sargassum {sup 232}Th or {sup 238}U level. Adsorption of {sup 232}Th particle to and incorporation of soluble {sup 238}U into algae body were suggested. Mean {sup 232}Th and {sup 238}U radioactivities were found 73 and 510 {mu}Bq/g wet wt, respectively, and the respective annual committed effective doses, 0.2 and 0.3 {mu}Sv, calculated from those values were confirmed to be enough lower than the annual public dose limit, 1 mSv. (K.H.)

  20. Origin of the {sup 238}U-{sup 230}Th disequilibrium in magmas from subduction zones: the Arenal example; Origine du desequilibre {sup 238}U-{sup 230}TH dans les magmas des zones de subduction: exemple de l`Arenal

    Energy Technology Data Exchange (ETDEWEB)

    Villemant, B [Paris-6 Univ., 75 (France)

    1997-12-31

    The existence in some volcanic products of strong excess of {sup 238}U with respect to {sup 230}Th is one of the characteristics of volcanic arc magmas. These excesses are generally attributed to fluid additions inside mantellic sources before magma segregation, differentiation and eruption. These fluids should be linked to the dehydration of the subducted rocks. These hypotheses are essentially based on correlations between {sup 10}Be, {sup 87}Sr anomalies, Ba/La ratios and on the distribution of volcanic centers with respect to the subduction zone. Recent studies suggest an evolution of the composition of volcanic sources in Central America from a depleted mantle type (MORB) in the North (Nicaragua) to a less transformed enriched type (OIB) in the South (Costa Rica). The Arenal volcano belongs to a transition zone between these two types. The preliminary study of trace elements and {sup 238}U-{sup 230}Th disequilibria in recent volcanic products (1968-1993) indicates a more complex situation. At least two different mantle sources were successively involved characterized by different Th/La and La/Yb ratios and very different to the OIB type. Also most lavas are in equilibrium with {sup 238}U/{sup 232}Th ratios of about 1.2 to 1.3. However, in eruptive cycle, some lavas are characterized by a strong {sup 238}U excess with respect to {sup 230}Th with cannot be linked to the sources, even when modified by fluids in depth. These results are interpreted in terms of heterogeneities of mantle sources and low depths late interactions with hydrothermal fluids during eruptions. Abstract only. (J.S.). 2 refs.

  1. Origin of the {sup 238}U-{sup 230}Th disequilibrium in magmas from subduction zones: the Arenal example; Origine du desequilibre {sup 238}U-{sup 230}TH dans les magmas des zones de subduction: exemple de l`Arenal

    Energy Technology Data Exchange (ETDEWEB)

    Villemant, B. [Paris-6 Univ., 75 (France)

    1996-12-31

    The existence in some volcanic products of strong excess of {sup 238}U with respect to {sup 230}Th is one of the characteristics of volcanic arc magmas. These excesses are generally attributed to fluid additions inside mantellic sources before magma segregation, differentiation and eruption. These fluids should be linked to the dehydration of the subducted rocks. These hypotheses are essentially based on correlations between {sup 10}Be, {sup 87}Sr anomalies, Ba/La ratios and on the distribution of volcanic centers with respect to the subduction zone. Recent studies suggest an evolution of the composition of volcanic sources in Central America from a depleted mantle type (MORB) in the North (Nicaragua) to a less transformed enriched type (OIB) in the South (Costa Rica). The Arenal volcano belongs to a transition zone between these two types. The preliminary study of trace elements and {sup 238}U-{sup 230}Th disequilibria in recent volcanic products (1968-1993) indicates a more complex situation. At least two different mantle sources were successively involved characterized by different Th/La and La/Yb ratios and very different to the OIB type. Also most lavas are in equilibrium with {sup 238}U/{sup 232}Th ratios of about 1.2 to 1.3. However, in eruptive cycle, some lavas are characterized by a strong {sup 238}U excess with respect to {sup 230}Th with cannot be linked to the sources, even when modified by fluids in depth. These results are interpreted in terms of heterogeneities of mantle sources and low depths late interactions with hydrothermal fluids during eruptions. Abstract only. (J.S.). 2 refs.

  2. Transfer Rates of 238U and 232Th for E. globulus, A. mearnsii, H. filipendula and Hazardous Effects of the Usage of Medicinal Plants From Around Gold Mine Dump Environs

    Directory of Open Access Journals (Sweden)

    Victor M. Tshivhase

    2015-12-01

    Full Text Available Medicinal plant consumption can be a source of human exposure to radioactive elements such as 238U and 232Th, which can lead to internal radiation doses. The uptake of 238U and 232Th from soils to the leaf samples of three different medicinal plant species (Eucalyptus globulus, Acacia mearnsii and Hyparrhenia filipendula from the purlieu of the Princess gold mine dump, an abandoned contaminated tailings storage site (TSS, located at longitude 27°55′00″E and latitude 26°09′30″S in Davidsonville (Roodepoort, west of Johannesburg, South Africa was measured. This was done using ICP-MS spectrometry and substantial differences were observed in the soil-plant transfer factor (TF values between these radionuclides. The plant species E. globulus exhibited the highest uptake of 238U, with an average TF of 3.97, while that of H. filipendula was 0.01 and the lowest TF of 0.15 × 10−2 was measured for A. mearnsii. However, in the case of 232Th, the highest average TF was observed for A. mearnsii (0.29, followed by E. globulus (0.10 and lowest was measured for H. filipendula (0.27 × 10−2. The ratio of TF average value i.e., 238U to 232Th in the soil-plant leaves was 38.05 for E. globulus, 0.01 for A. mearnsii and 4.38 for H. filipendula.

  3. Transfer Rates of 238U and 232Th for E. globulus, A. mearnsii, H. filipendula and Hazardous Effects of the Usage of Medicinal Plants From Around Gold Mine Dump Environs

    Science.gov (United States)

    Tshivhase, Victor M.; Njinga, Raymond L.; Mathuthu, Manny; Dlamini, Thulani C.

    2015-01-01

    Medicinal plant consumption can be a source of human exposure to radioactive elements such as 238U and 232Th, which can lead to internal radiation doses. The uptake of 238U and 232Th from soils to the leaf samples of three different medicinal plant species (Eucalyptus globulus, Acacia mearnsii and Hyparrhenia filipendula) from the purlieu of the Princess gold mine dump, an abandoned contaminated tailings storage site (TSS), located at longitude 27°55′00″E and latitude 26°09′30″S in Davidsonville (Roodepoort, west of Johannesburg, South Africa) was measured. This was done using ICP-MS spectrometry and substantial differences were observed in the soil-plant transfer factor (TF) values between these radionuclides. The plant species E. globulus exhibited the highest uptake of 238U, with an average TF of 3.97, while that of H. filipendula was 0.01 and the lowest TF of 0.15 × 10−2 was measured for A. mearnsii. However, in the case of 232Th, the highest average TF was observed for A. mearnsii (0.29), followed by E. globulus (0.10) and lowest was measured for H. filipendula (0.27 × 10−2). The ratio of TF average value i.e., 238U to 232Th in the soil-plant leaves was 38.05 for E. globulus, 0.01 for A. mearnsii and 4.38 for H. filipendula. PMID:26690462

  4. Measurement of 238U, 232Th and 40K concentrations in different regions of Colombia

    Science.gov (United States)

    Rodríguez, W.; Lizarazo, C.; Cortés, M. L.; Rodríguez, S. A.; Mendoza, E. F.; Cristancho, F.

    2012-02-01

    Taking into account the wide variety of geological structures in Colombia, we took a collection of samples both from sand beaches and high mountains systems and determined their concentration of 238U, 232Th and 40K using a high resolution gamma spectrometry system. The results show a variation of these concentrations for the different samples that we associate with the soil type and the environmental conditions of the chosen regions. We also compare our results with other studies carried out in regions with similar geological conditions.

  5. Decay of the isoscalar giant monopole resonance in 208Pb and 238U

    International Nuclear Information System (INIS)

    Woude, A. van der

    1985-01-01

    In this paper, the neutron decay of the giant monopole resonance (GMR) of 208 Pb and the alpha decay of the GMR of 238 U is studied. The GMR is excited by inelastic alpha-scattering at small angles (0-3deg) using 120 MeV alpha particles. The interference of other processes like the knock-out process with the particle decay of these resonances is considered. Coincidence neutron and alpha spectra are presented, as well as E2/E0 strength distributions. (Auth.)

  6. Angular distribution of photofission fragments in 238U at 5.43 MeV

    International Nuclear Information System (INIS)

    Kuniyoshi, S.; Mafra, O.Y.; Renner, C.; Goldemberg, J.

    1974-01-01

    The angular distribution of photofission fragments of 238 U, produced by 5.43 MeV monochromatic photons from the eta,γ reaction in sulphur, has been measured using glass plates as detectors. In the analysis of the results only the contributions from the (J sup(π), K) 1= (1 - ,0), (1 - ,1) and (2 + ,0) terms were considered. The coefficients of the angular distributions of the fission fragments were obtained. An analysis of the data available in the literature on the angular distribution near the photofission threshold is also presented

  7. Angular distribution of photofission fragments in 238U at 5.43 MeV

    International Nuclear Information System (INIS)

    Kuniyoshi, Susumo

    1973-01-01

    The angular distribution of photofission fragments of 238 U, produced by 5.43 MeV monochromatic photons from the η,γ reaction in sulphur, has been measured using glass plates as detectors. In the analysis of the results only the contributions from the (J π , K) 1= (1 - ,0), (1 - ,1) and (2 + ,0) terms were considered. The coefficients of the angular distributions of the fission fragments were obtained. An analysis of the data available in the literature on the angular distribution near the photofission threshold is also presented. (author)

  8. Activity disequilibrium between 234U and 238U isotopes in natural environment

    OpenAIRE

    Bory?o, Alicja; Skwarzec, Bogdan

    2014-01-01

    The aim of this work was to calculate the values of the 234U/238U activity ratio in natural environment (water, sediments, Baltic organisms and marine birds from various regions of the southern Baltic Sea; river waters (the Vistula and the Oder River); plants and soils collected near phosphogypsum waste heap in Wi?linka (Northern Poland) and deer-like animals from Northern Poland. On the basis of the studies it was found that the most important processes of uranium geochemical migration in th...

  9. A study on possible use of Urtica dioica (common nettle) plants as uranium (234U, 238U) contamination bioindicator near phosphogypsum stockpile.

    Science.gov (United States)

    Olszewski, Grzegorz; Boryło, Alicja; Skwarzec, Bogdan

    The aim of this study was to determine uranium concentrations in common nettle ( Urtica dioica ) plants and corresponding soils samples which were collected from the area of phosphogypsum stockpile in Wiślinka (northern Poland). The uranium concentrations in roots depended on its concentrations in soils. Calculated BCF and TF values showed that soils characteristics and air deposition affect uranium absorption and that different uranium species have different affinities to U . dioica plants. The values of 234 U/ 238 U activity ratio indicate natural origin of these radioisotopes in analyzed plants. Uranium concentration in plants roots is negatively weakly correlated with distance from phosphogypsum stockpile.

  10. A study on possible use of Urtica dioica (common nettle) plants as uranium (234U, 238U) contamination bioindicator near phosphogypsum stockpile

    International Nuclear Information System (INIS)

    Olszewski, Grzegorz; Borylo, Alicja; Skwarzec, Bogdan

    2016-01-01

    The aim of this study was to determine uranium concentrations in common nettle (Urtica dioica) plants and corresponding soils samples which were collected from the area of phosphogypsum stockpile in Wislinka (northern Poland). The uranium concentrations in roots depended on its concentrations in soils. Calculated BCF and TF values showed that soils characteristics and air deposition affect uranium absorption and that different uranium species have different affinities to U. dioica plants. The values of 234 U/ 238 U activity ratio indicate natural origin of these radioisotopes in analyzed plants. Uranium concentration in plants roots is negatively weakly correlated with distance from phosphogypsum stockpile. (author)

  11. Photon-induced Fission Product Yield Measurements on 235U, 238U, and 239Pu

    Science.gov (United States)

    Krishichayan, Fnu; Bhike, M.; Tonchev, A. P.; Tornow, W.

    2015-10-01

    During the past three years, a TUNL-LANL-LLNL collaboration has provided data on the fission product yields (FPYs) from quasi-monoenergetic neutron-induced fission of 235U, 238U, and 239Pu at TUNL in the 0.5 to 15 MeV energy range. Recently, we have extended these experiments to photo-fission. We measured the yields of fission fragments ranging from 85Kr to 147Nd from the photo-fission of 235U, 238U, and 239Pu using 13-MeV mono-energetic photon beams at the HIGS facility at TUNL. First of its kind, this measurement will provide a unique platform to explore the effect of the incoming probe on the FPYs, i.e., photons vs. neutrons. A dual-fission ionization chamber was used to determine the number of fissions in the targets and these samples (along with Au monitor foils) were gamma-ray counted in the low-background counting facility at TUNL. Details of the experimental set-up and results will be presented and compared to the FPYs obtained from neutron-induced fission at the same excitation energy of the compound nucleus. Work supported in part by the NNSA-SSAA Grant No. DE-NA0001838.

  12. Estimation of radionuclide concentration of 238U, 226Ra, 232Th in air in Wuhan city

    International Nuclear Information System (INIS)

    Shi Jinhua; Chen Changhua

    1989-01-01

    The concentrations of 238 U, 226 Ra and 232 Th in air in Wuhan area were estimated by assuming that they originate from resuspended particles of soil and investigating the dust content in air and the concentrations of these radionuclides in soil. 60 soil samples were collected from April to October, 1984, and 7346 air dust samples during 1981-1985. The estimated mean air concentrations of 238 U, 226 Ra and 232 Th were 24.0 x 10 -9 , 18.9 x 10 -9 and 28.7 x 10 -9 , Bq/L, respectively. Their highest values were observed of 30.4 x 10 -9 , 23.9 x 10 -9 and 36.2 x 10 -9 Bq/L in 1983. Seasonal change of the concentrations was clear as shown in the data of 1984 and 1985, which was related to the meterological conditions. Among the 6 districts of Wuhan city, the highest concentration was in Qingshan and the lowest in Wuchang

  13. (238)U and total radioactivity in drinking waters in Van province, Turkey.

    Science.gov (United States)

    Selçuk Zorer, Özlem; Dağ, Beşir

    2014-06-01

    As part of the national survey to evaluate natural radioactivity in the environment, concentration levels of total radioactivity and natural uranium have been analysed in drinking water samples. A survey to study natural radioactivity in drinking waters was carried out in the Van province, East Turkey. Twenty-three samples of drinking water were collected in the Van province and analysed for total α, total β and (238)U activity. The total α and total β activities were counted by using the α/β counter of the multi-detector low background system (PIC MPC-9604), and the (238)U concentrations were determined by inductively coupled plasma-mass spectrometry (Thermo Scientific Element 2). The samples were categorised according to origin: tap, spring or mineral supply. The activity concentrations for total α were found to range from 0.002 to 0.030 Bq L(-1) and for total β from 0.023 to 1.351 Bq L(-1). Uranium concentrations ranging from 0.562 to 14.710 μg L(-1) were observed in drinking waters. Following the World Health Organisation rules, all investigated waters can be used as drinking water.

  14. Delayed neutron kinetic functions for /sup 232/Th and /sup 238/U mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Ganich, P P; Goshovskij, M V; Lendel, A I; Lomonosov, V I; Sikora, D I; Sychev, S I

    1984-11-01

    In order to investigate the applicability of the method based on using kinetic functions, describing the emission of delayed neutrons by samples for determination of the content of fissionable nuclides in binary mixtures, the /sup 232/Th+/sup 238/U mixtures have been analyzed with the M-30 microtron. Fresh samples containing ThO/sub 2/, U/sub 3/O/sub 8/ and their mixtures are irradiated by bremstrahlung at the 15.5 MeV energy of accelerated electrons and 9 ..mu..A average current. The mass of samples is about 6 g. To determine the kinetic functions, temporal distributions of delayed neutron pulses are used, their maximum number for different samples being (1.7-3.0) x 10/sup 4/. In processing the data obtained two methods of normalization of the delayed neutron number in the kinetic functions are used: to the total yield of delayed neutrons and to the yield of /sup 133/I ..gamma..-quanta. The conclusion is drawn that the method investigated permits to determine relative /sup 238/U concentrations in the mixtures considered with 0.06-0.2 errors. Error reduction is achieved during the normalization of the number of delayed neutrons to the yield of /sup 130/I ..gamma..-quanta.

  15. Electric quadrupole giant resonance in the photofission of sup(238)U IFUSP-P--140

    International Nuclear Information System (INIS)

    Bhandari, B.S.; Arruda Neto, J.D.T.; Herdade, S.B.; Nascimento, I.C.

    1978-02-01

    The 238 U nucleus was studied measuring the electrofission yield and angular distributions of fission fragments, in the energy range of 5.5 to 28.3 MeV, using a new method of analysis. An E2 isoscalar giant resonance was found in the photofission cross section of 238 U. This resonance exhausts (71 + -7)% of the EWSR and is located at 9.9 + -0.2 MeV with a width of 6.8 + -0.4 MeV. The position of this resonance is in reasonable agreement with the Bohr and Mottelson prediction (58.Asup( - 1/3MeV). The width of 6.8 + -0.4 MeV is compatible with a possible triple splitting of the resonance. From the angular distributions of photofission fragments and yield measurements of multipoles other than E1, evidence of an M1 mixture in the energy region 6-7 MeV was found

  16. Measurements of 234U, 238U and 230Th in excreta of uranium-mill crushermen

    International Nuclear Information System (INIS)

    Fisher, D.R.; Jackson, P.O.; Brodacynski, G.G.; Scherpelz, R.I.

    1982-07-01

    Uranium and thorium levels in excreta of uranium mill crushermen who are routinely exposed to airborne uranium ore dust were measured. The purpose was to determine whether 230 Th was preferentially retained over either 234 U or 238 U in the body. Urine and fecal samples were obtained from fourteen active crushermen with long histories of exposure to uranium ore dust, plus four retired crushermen and three control individuals for comparison. Radiochemical procedures were used to separate out the uranium and thorium fractions, which were then electroplated on stainless steel discs and assayed by alpha spectrometry. Significantly greater activity levels of 234 U and 238 U were measured in both urine and fecal samples obtained from uranium mill crushermen, indicating that uranium in the inhaled ore dust was cleared from the body with a shorter biological half-time than the daughter product 230 Th. The measurements also indicated that uranium and thorium separate in vivo and have distinctly different metabolic pathways and transfer rates in the body. The appropriateness of current ICRP retention and clearance parameters for 230 Th in ore dust is questioned

  17. 232Th/238U in a uranium mobility estimate in an agricultural area in the municipality of Pedra-Pernambuco - Brazil

    International Nuclear Information System (INIS)

    Santos Junior, Jose Araujo dos; Amaral, Romilton dos Santos; Bezerra, Jairo Dias; Damascena, Kennedy Francys Rodrigues; Oliveira, Jose Valdez Monterazo de; Bispo, Rodrigo Cesar Bezerra; Silva, Cleomacio Miguel da; Rocha, Edilson Accioly

    2011-01-01

    The mobility of the radionuclides in soil depends primarily on the physic-chemical parameters. The uranium is easily oxidized in aqueous environment, which allows its characterization with higher mobility. The Thorium is practically insoluble, mainly if the environment has organic matter and sulfates. The geochemical characteristics of the rocks, associated with the weather and metamorphism produce alterations in the concentration diagrams of the natural radionuclides in different types of soil. The ratio 232 Th/ 238 U has been used as an indicator of oxidizing and reducing conditions. Th/U less than 2 suggests that the uranium is in its concentrated form abundantly when compared to the thorium. In reducing conditions, the value Th/U higher than 7 indicates a removal of the uranium. In this work it was possible to analyze the agricultural soil in the municipality of Pedra, Pernambuco, Brazil where there are uranium anomaly and thorium in rocky outcrops. Sixty-two samples of the horizon C soil were collected, in an area of 2 km 2 , where the main uranium occurrences are located. The analyses were done by High-Resolution Gamma-Spectroscopy. In the analyses the secular equilibrium was assumed and the 238 U and the 232 Th specific activities were used to estimate the oxidizing and reducing conditions defining the uranium mobility in the soil. The obtained findings show that the ratio Th/U varied from 0.3 to 13.4, with average of 4.6. The biggest 238 U fraction was fix (80.3%), with low mobility; the smallest fraction concentrated (6.6%) and a lixiviated intermediate fraction (13.1%). (author)

  18. Radioactive Contamination of Alluvial Soils in the Taiga Landscapes of Yakutia with 137Cs, 226Ra, and 238U

    Science.gov (United States)

    Chevychelov, A. P.; Sobakin, P. I.

    2017-12-01

    The concentrations and distribution of 137Cs in alluvial soils (Fluvisols) of the upper and middle reaches of the Markha River in the northwest of Yakutia and 226Ra and 238U in alluvial soils within the El'kon uranium ore deposit in the south of Yakutia have been studied. It is shown that the migration of radiocesium in the permafrost-affected soils of Yakutia owing to alluviation processes extends to more than 600 km from the source of the radioactive contamination. The migration of 137Cs with water flows is accompanied by its deposition in the buried horizons of alluvial soils during extremely high floods caused by ice jams. In the technogenic landscapes of southern Yakutia, active water migration of 238U and 226Ra from radioactive dump rocks. The leaching of 238U with surface waters from the rocks is more intense than the leaching of 226Ra. The vertical distribution patterns of 238U and 226Ra in the profiles of alluvial soils are complex. Uranium tends to accumulate in the surface humus horizon and in the buried soil horizons, whereas radium does not display any definite regularities of its distribution in the soil profiles. At present, the migration of 238U and 226Ra with river water and their accumulation in the alluvial soils extend to about 30 km from the source.

  19. Magmatic evolution of a volcano studied by 230Th-238U disequilibrium and trace elements systematics: the Etna case

    International Nuclear Information System (INIS)

    Condomines, M.; Allegre, C.J.; Tanguy, J.C.; Kieffer, G.

    1982-01-01

    Age determinations of several lava flows from Etna through 230 Th- 238 U disequilibrium (internal isochrons) yield a precise chronology of the volcano's history for the last 200,000 years, and emphasize the main episodes in the formation of this huge complex strato-volcano. Study of ( 230 Th/ 232 Th) 0 initial ratios of lavas together with their trace-element compositions yields a consistent model of magmatic evolution implying the existence, for 200,000 years, of a deep reservoir of alkalic magma periodically mixed with magmas of tholeiitic affinity. These short periods of mixing appear to be related to the formation of the large calderas of Etna. In addition to these processes affecting the deep reservoir, fractional crystallization also occurred in more superficial levels of the volcanic edifice, thereby yielding several series of differentiation of relatively short duration. As for its geochemistry, Etna's volcanism is of oceanic type but with its own characteristics and in a peculiar geodynamic context, at the edge of the African Plate. (author)

  20. Distribution of 238U, 232Th, 40K, and 137Cs concentrations in soil samples nearby a nuclear laboratory, Capao Island, Brazil

    Directory of Open Access Journals (Sweden)

    Oliveira Luciano S.R.

    2015-01-01

    Full Text Available Absolute soil concentrations of 238U, 232Th, 40K, and 137Cs samples were measured using high-resolution gamma spectrometry. The area of interest encompasses an embankment in a mangrove swamp in Guaratiba, Rio de Janeiro, called Capao Island, where nuclear, chemical and biological defense laboratories of the Brazilian Army Technology Center are in operation for more than 30 years. In order to ensure that no significant environmental impact has resulted from neutron physics experiments performed in a graphite exponential pile in addition to the operation of two cesium-driven irradiating facilities, radiation monitoring of the isotopes was carried out. A total of eight 250 ml soil samples were extracted within an area of 300 m x 300 m. No trace of 137Cs was detected and the measured levels of 238U were found to be close to the global mean. However, some data that slightly exceeded the expected normal range for 232Th (60 % of samples and 40K (20 % of samples should be attributed to the construction debris (cement, rocks, and sand used in the embankment at the site. Since there is no handling of those isotopes at that site or adjacent facilities that could affect their presence, it was concluded that no detectable contamination has occurred.

  1. Use of LabSOCS for determination of specific concentrations of 40K, 238U and 232Th in fertilizer samples

    International Nuclear Information System (INIS)

    Garcez, Ricardo Washington Dutra; Lopes, Jose Marques; Silva, Ademir Xavier da; Domingues, Alessandro Mariano; Lima, Marco Frota

    2015-01-01

    Use of fertilizer is an established practice worldwide to promote agricultural productivity increased without increasing the planted area, resulting in native forests protection and increase of the food availability. Some kinds of fertilizer have in their chemical composition some radionuclides due the origin of its feedstock, such as 238 U, the 232 Th, and their descendants, beyond 40 K. Knowledge of the radioactivity levels in the environment is great importance to know the gamma radiation dose that the human being is exposed. For identification and quantitation of radionuclides, it was used gamma spectrometry where HPGe detector was used to obtain the spectra, and LabSOCS software for calculating the detection efficiency for each energy. The values of 232 Th specific concentrations ranged from 4.1 to 368.1 Bq.Kg -1 , the values of 238 U specific concentrations ranged from 16.0 to 647.7 Bq.Kg -1 and 40 K specific concentrations ranged from 19.1 to 12713 Bq.Kg -1 . Concentrations of values are consistent with those found in literature. (author)

  2. Measurement of the 238U(n ,γ ) cross section up to 80 keV with the Total Absorption Calorimeter at the CERN n_TOF facility

    Science.gov (United States)

    Wright, T.; Guerrero, C.; Billowes, J.; Cano-Ott, D.; Mendoza, E.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Bécares, V.; Barbagallo, M.; Bečvář, F.; Belloni, F.; Berthoumieux, E.; Bosnar, D.; Brugger, M.; Calviño, F.; Calviani, M.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Dietz, M.; Domingo-Pardo, C.; Durán, I.; Dzysiuk, N.; Eleftheriadis, C.; Ferrari, A.; Fraval, K.; Furman, V.; Gómez-Hornillos, M. B.; Ganesan, S.; García, A. R.; Giubrone, G.; Gonçalves, I. F.; González-Romero, E.; Goverdovski, A.; Griesmayer, E.; Gunsing, F.; Gurusamy, P.; Heftrich, T.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Käppeler, F.; Kadi, Y.; Karadimos, D.; Katabuchi, T.; Ketlerov, V.; Khryachkov, V.; Koehler, P.; Kokkoris, M.; Kroll, J.; Krtička, M.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Leong, L. S.; Lerendegui-Marco, J.; Losito, R.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Paradela, C.; Pavlik, A.; Perkowski, J.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego-Perez, A.; Robles, M.; Roman, F.; Rubbia, C.; Ryan, J. A.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Sedyshev, P.; Tagliente, G.; Tain, J. L.; Tarifeño-Saldivia, A.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Valenta, S.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vermeulen, M. J.; Versaci, R.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiss, C.; Žugec, P.; n TOF Collaboration

    2017-12-01

    The radiative capture cross section of a highly pure (99.999%), 6.125(2) grams and 9.56(5)×10-4 atoms/barn areal density 238U sample has been measured with the Total Absorption Calorimeter (TAC) in the 185 m flight path at the CERN neutron time-of-flight facility n_TOF. This measurement is in response to the NEA High Priority Request list, which demands an accuracy in this cross section of less than 3% below 25 keV. These data have undergone careful background subtraction, with special care being given to the background originating from neutrons scattered by the 238U sample. Pileup and dead-time effects have been corrected for. The measured cross section covers an energy range between 0.2 eV and 80 keV, with an accuracy that varies with neutron energy, being better than 4% below 25 keV and reaching at most 6% at higher energies.

  3. Two-phonon giant resonances in 136Xe, 208Pb, and 238U

    International Nuclear Information System (INIS)

    Boretzky, K.; Gruenschloss, A.; Ilievski, S.; Adrich, P.; Aumann, T.; Bertulani, C.A.; Cub, J.; Dostal, W.; Eberlein, B.; Elze, T.W.; Emling, H.; Fallot, M.; Holeczek, J.; Holzmann, R.; Kozhuharov, C.; Kratz, J.V.; Kulessa, R.; Leifels, Y.; Leistenschneider, A.; Lubkiewicz, E.; Mordechai, S.; Ohtsuki, T.; Reiter, P.; Simon, H.; Stelzer, K.; Stroth, J.; Suemmerer, K.; Surowiec, A.; Wajda, E.; Walus, W.

    2003-07-01

    The excitation of the double-phonon giant dipole resonance was observed in heavy projectile nuclei impinging on targets of high nuclear charge with energies of 500-700 MeV/nucleon. New experimental data are presented for 136 Xe and 238 U together with further analysis of earlier data on 208 Pb. Differential cross sections dσ/dE * and dσ/dθ for electromagnetic excitations were deduced. Depending on the isotope, cross sections appear to be enhanced in comparison to those expected from a purely harmonic nuclear dipole response. The cumulative effect of excitations of two-phonon states composed of one dipole and one quadrupole phonon, of predicted anharmoniticies in the double-phonon dipole response, and of damping of the dipole resonance during the collision may account for the discrepancy. In addition, decay properties of two-phonon resonances were studied and compared to that of a statistical decay. (orig.)

  4. The evaluation of the mass distribution data for 238U, 239Pu and 242Pu fission

    International Nuclear Information System (INIS)

    Liu Tingjin

    2002-01-01

    The mass distribution data for 238 U at E n =1.5, 5.5, 8.3, 11.3, 14.9, 22.0, 27.5, 50.0, 99.5, 160.0 MeV, E p =20.0, 60.0 MeV 239 Pu at E n =0.17, 7.9, 14.5 MeV and 242 Pu at E n =15.1 MeV were evaluated and recommended based on the main available experimental data up to now. The experimental data were make necessary corrections and their errors were also made necessary adjustments. The problems concerned were discussed

  5. Possible evidence for shape isomeric γ-decay in μ- atoms of 238U

    International Nuclear Information System (INIS)

    Fromm, W.D.; Ortlepp, H.-G.; Polikanov, S.M.; Schmidt, U.; Zorin, G.N.; Arlt, R.; Musiol, G.

    1977-01-01

    A search for the γ-decay of the shape isomer in muonic 238 U excited by radiationless transitions has been performed. Seven delayed transitions in the energy region of 700 to 3200 keV have been observed with a large Ge(Li) detector. Two transitions with Esub(γ)=2215 and 3131 keV have been attributed to the decay of the shape isomeric state into levels in the first well. The isomeric shift of the second minimum Esub(II) approximately 600 keV in the presence of the muon and the decrease of the lifetime of the shape isomer to tau=12+-2 ns give arguments in favour of the connection of shape isomerism with large quadrupole deformations. (Auth.)

  6. 238U decay series nuclides in the northeastern Arabian Sea: scavenging rates and cycling processes

    International Nuclear Information System (INIS)

    Sarin, M.M.; Krishnaswami, S.; Ramesh, R.; Somayajulu, B.L.K.

    1994-01-01

    The extent of radioactive disequilibrium between 234 Th- 238 U, 210 Po- 210 Pb and 210 Pb- 226 Ra has been measured in four vertical profiles from the northeastern Arabian Sea, a region characterized by oxygen deficient and denitrification layers at intermediate depths. The most common feature of the data is that the dissolved concentrations of the daughter nuclides are considerably less than those of their parents, exceptions being the near equilibrium or excess concentrations of 210 Po (relative to 210 Pb) at ∼ 100 m and that of 210 Pb relative to 226 Ra in surface waters. These results suggest that scavenging of dissolved 234 Th, 210 Po and 210 Pb occurs throughout the water column in the northeastern Arabian Sea. (Author)

  7. Cluster decay channel in 238U + 40Ar (243 MeV)

    International Nuclear Information System (INIS)

    Pyatkov, Yu.V.; Penionzhkevich, Yu.Eh.; Osetrov, O.I.

    1999-01-01

    The reaction 238 U + 40 Ar (E lab = 243 MeV) was studied. For the first time a pronounced fine structure (FS) in the form of distinct peaks has been observed in the mass yields of the fragments of the 278 110 nuclear system decay at the initial excitation of about 60 MeV. The FS peaks are located in the vicinity of the mass numbers A ∼ 70, 100, 130, which are specific for magic nuclei (clusters) of Ni, Ge, Zr, Sn, Sr. The FS peaks contain only low-energy events linked with the very elongated prescission configurations of the system. Some events are observed which can be treated as an indication of ternary fission via such configurations with the appearance of two equal clusters. Hence presumably the collinear cluster tripartition channel is realized observed earlier in the spontaneous fission of 248 Cm and 252 Cf nuclei

  8. Independent Yields of Kr Isotopes at Photofission of $^{232}$Th and $^{238}$U

    CERN Document Server

    Gangrsky, Yu P; Zemlyanoi, S G; Maslova, N Yu; Myshinskii, G V; Norov, K S; Penionzhkevich, Yu E; Selesh, O

    2002-01-01

    The yields of the primary fission fragments - Kr isotopes - at the photofission of ^{232}Th and ^{238}U were measured. The experiments were performed at the microtron of FLNR, JINR, with the energy of the accelerated electrons 25 MeV. The methodic of fission fragments transportation by the gas flow through the capillary and condensation of the inert gases in the cryostat at the liquid nitrogen temperature was used. The fission fragments of other elements were stopped by the filter on the entrance of the capillary. The identification of the Kr isotopes was performed using the gamma-spectra of their daughter products. The mass distribution of the Kr isotopes independent yields was obtained and the comparison with yields at the prompt and thermal neutron fission was discussed.

  9. Inelastic neutron excitation of the ground state rotational band of 238U

    International Nuclear Information System (INIS)

    Guenther, P.; Smith, A.

    1975-01-01

    Cross sections for the neutron excitation of the 2+(45 keV), 4+(148 keV) and 6+(308 keV) states in 238 U were measured to incident energies of approximately 3.0 MeV. The experimental resolution was sufficient to resolve these components throughout the measured energy range. Particular attention was given to energies near threshold and in the few MeV range where direct reaction contributions were appreciable. The experimental results were compared with theoretical estimates based upon statistical and coupled-channel models deduced from comprehensive studies of neutron scattering from heavy-rotational-deformed nuclei. An evaluated inelastic scattering data set was derived from the present experimental and calculational results and previously reported experimental values and compared with respective values from the ENDF-IV file. 4 figures

  10. Electromagnetic fission of 238U at 600 and 1000 MeV per nucleon

    International Nuclear Information System (INIS)

    Rubehn, T.; Mueller, W.F.J.; Bassini, R.; Begemann-Blaich, M.; Blaich, T.; Gross, C.; Imme, G.; Iori, I.; Kunde, G.J.; Kunze, W.D.; Lindenstruth, V.; Lynen, U.; Moehlemkamp, T.; Moretto, L.G.; Ocker, B.; Pochodzalla, J.; Raciti, G.; Reito, S.; Sann, H.; Schuettauf, A.; Serfling, V.; Trautmann, W.; Trzcinski, A.; Verde, G.; Woerner, A.; Zude, E.; Zwieglinski, B.

    1995-05-01

    Electromagnetic fission of 238 U projectiles at E/A=600 and 1000 MeV was studied with the ALADIN spectrometer at the heavy-ion synchrotron SIS. Seven different targets (Be, C, Al, Cu, In, Au and U) were used. By considering only those fission events where the two charges added up to 92, most of the nuclear interactions were excluded. The nuclear contributions to the measured fission cross sections were determined by extrapolating from beryllium to the heavier targets with the concept of factorization. The obtained cross sections for electromagnetic fission are well reproduced by extended Weizsaecker-Williams calculations which include E1 and E2 excitations. The asymmetry of the fission fragments' charge distribution gives evidence for the excitation of the double giant-dipole resonance in uranium. (orig.)

  11. Influence of soil structure on the "Fv approach" applied to 238U and 226Ra.

    Science.gov (United States)

    Blanco Rodríguez, P; Vera Tomé, F; Lozano, J C

    2017-02-01

    The soil-to-plant transfer factors were determined in a granitic area for the two long-lived uranium series radionuclides 238 U and 226 Ra. With the aim to identify a physical fraction of soil whose concentration correlates linearly with the plant concentration, the soil compartment was analyzed in various stages. An initial study identified the soil compartments as being either bulk soil or its labile fraction. The bulk soil was subsequently divided into three granulometric fractions consisting of: coarse sand, fine sand, and silt and clay. The soil-to-plant transfer of radionuclides for each of these three texture fractions was analyzed. Lastly, the labile fraction was extracted from each textural part, and the activity concentration of the radionuclides 238 U and 226 Ra was measured. In order to assess the influence of soil texture on the soil-to-plant transfer process, we sought to identify possible correlations between the activity concentration in the plant compartment and those found in the different fractions within each soil compartment. The results showed that the soil-to-plant transfer process for uranium and radium depends on soil grain size, where the results for uranium showed a linear relationship between the activity concentration of uranium in the plant and the fine soil fraction. In contrast, a linear relation between the activity concentration of radium in the plant and the soil coarse-sand fraction was observed. Additionally, the presence of phosphate and calcium in the soil of all of the compartments studied affected the soil-to-plant transfer of uranium and radium, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Application of Energy Window Concept in Doppler Broadening of {sup 238}U Cross Section

    Energy Technology Data Exchange (ETDEWEB)

    Khassnov, Azamat; Choi, Soo Young; Lee, Deok Jung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-10-15

    Currently, the NJOY code is used for construction and Doppler broadening of microscopic cross sections. There exist several methods or formalisms to produce microscopic cross sections and there are also different methods of Doppler broadening. In this paper, Multi-Level Breit-Wigner (MLBW) formalism and the Psi method are used for generation and Doppler broadening of the resonance cross section. Accuracy of the energy window concept applied MLBW (EW MLBW) Doppler broadened cross section was compared with that of the cross section generated by conventional MLBW (Con MLBW) formalism for {sup 2}38U isotope using MATLAB. The conventional method requires Doppler broadening of all resonances, including resonances far from the target energy point, which do not change much with respect to the temperature change. The energy window concept makes Doppler broadening possible with a smaller number of resonances neighboring to the energy point we are interested in, and just adds up 0 K temperature cross sections of other resonances. Multi-level Breit-Wigner formalism and the Doppler broadening method were used to construct microscopic cross sections of {sup 238}U at different temperatures. The energy window concept was applied only for the 1st resonance energy region (4.5∼11.2 eV). The energy window concept demonstrates high competitiveness because the relative differences were less than 0.0016% for all types of cross sections. The advantage of the energy window concept is that the number of resonances broadened for every energy point is significantly reduced, which allows a reduction of computation time by almost 45 % of Doppler broadening time of the cross section generation at temperatures higher than 0 K.

  13. Possible viscosity effects in neutron-induced fission of 232Th and 238U

    International Nuclear Information System (INIS)

    Gindler, J.E.; Glendenin, L.E.; Wilkins, B.D.

    1979-01-01

    Fission yields induced in the 238 U(n,f) and 232 Th(n,f) reactions were determined as a function of incident neutron energy (E/sub n/). The ratio of 115 Cd-to- 140 Ba yields as a function of E/sub n/ is analyzed by means of the equation Y 1 /Y 2 = exp[2(a 1 (E/sub n/+E 1 )/sup 1/2/ -2(a 2 (E/sub n/+E 2 )/sup 1/2/] to give values of a/sub i/, the level density parameter, and E/sub i/, the excitation energy for E/sub n/=0. The energies E/sub i/ are interpreted on the basis of the liquid drop model with shell and pairing corrections. Values are deduced for the energy dissipated by viscosity effects in the descent from the saddle point to the point where masses are fixed in the fissioning nucleus. These values are 1.7 MeV for 232 Th(n,f) and 4.8 MeV for 238 U(n,f). These values are consistent with the experimental observation that anti ν/sub p/ is approx. 0.6 neutron greater for 239 U fission than for 233 Th fission and that strong odd--even (nucleon pairing) effects are found in the fragment total kinetic energy distribution for 230 Th fission but not for 234 U fission. The low dissipation energy values together with the low values of pre-scission kinetic energy deduced by Guet, et al., [Nucl. Phys. A134 (1971)1] indicate a shorter path from the saddle point of the fissioning nucleus to scission than is generally assumed in theoretical calculations. 31 references

  14. Performance evaluation of indigenous thermal ionization mass spectrometer for determination of 235U/238U atom ratios

    International Nuclear Information System (INIS)

    Alamelu, D.; Parab, A.R.; Sasi Bhushan, K.; Shah, Raju V.; Jagdish Kumar, S.; Rao, Radhika M.; Aggarwal, S.K.; Bhatia, R.K.; Yadav, V.K.; Sharma, Madhavi P.; Tulsyan, Puneet; Chavda, Pradip; Sriniwasan, P.

    2014-07-01

    A magnetic sector based Thermal Ionization Mass Spectrometer (TIMS) designed and developed at Technical Physics Division, B.A.R.C., was evaluated for its performance for the determination of 235 U/ 238 U atom ratios in uranium samples. This consisted of evaluating the precision and accuracy on the 235 U/ 238 U atom ratios in various isotopic reference materials as well as indigenously generated uranium samples. The results obtained by the indigenous TIMS were also compared with those obtained using a commercially available TIMS system. The internal and external precision were found to be around 0.1% for determining 235 U/ 238 U atom ratios close to those of natural uranium ( i.e. 0.00730). (author)

  15. Effect of nonaxial and hexadecapole deformation on the hyperfine splitting of energy levels in 238U muonic atoms

    International Nuclear Information System (INIS)

    Bagaev, V.I.; Mikhajlov, I.N.; Ortlepp, Kh.G.; Fromm, V.D.

    1979-01-01

    The effect of nonaxial and hexadecapole deformation on spectra of moun atoms is considered, the model of rigid nonaxial rotator being used. Experimental data on μ -238 U obtained on the JINR synchrocyclotron are presented. The effect of monopolar, quadrupolar and hexadecapolar parts of potential on muon spectrum is studied using a separated beam of negative 105 MeV/c muons, as the contribution of other harmonics is negligible. Wave functions of 238 U nucleus are determined in the framework of the Davydov-Filipov model. The values of charge distribution parameters obtained for 238 U are compared with available ones. The comparison shows that the effect of nuclear polarization on quadrupolar splitting of n→n-1 transitions decreases with the growth of n. Quadrupolar splitting of 4F→3D transitions is sufficiently large for experimental studies. Besides, vacuum polarization, radial charge distribution etc. produce an insignificant effect on the above transitions

  16. 238U-230Th-226Ra radioactive disequilibria in the products from 1707 eruption of Fuji volcano, Japan

    International Nuclear Information System (INIS)

    Kurihara, Yuichi; Takahashi, Masaomi; Sato, Jun

    2008-01-01

    Time scale of magmatic processes in the 1707 eruptive activity of Fuji volcano, Japan, was estimated by the 238 U- 230 Th- 226 Ra disequilibria observed in the 1707 volcanic products. The activity ratios of 226 Ra/ 230 Th in the products were larger than unity, being enriched in 226 Ra relative to 230 Th. The decay-corrected 226 Ra/ 230 Th activity ratio to the time of the eruption versus 238 U/ 230 Th activity ratio diagram for the 1707 volcanic products showed a positive correlation, suggesting that the 238 U/ 230 Th- 226 Ra disequilibria occurred during the magma genesis of Fuji volcano. The 230 Th- 226 Ra disequilibria in the 1707 volcanic products suggested that the time scale from the magma genesis to the eruption, including the melting of the mantle wedge, magma storage and magmatic differentiation from basalt to andesite, was less than 8000 years. (author)

  17. Angular distribution of fragments from neutron-induced fission of 238U in the intermediate energy region

    International Nuclear Information System (INIS)

    Carlsson, Magnus

    2004-06-01

    Areas ranging from nuclear structure models to accelerator-driven systems benefit from improved neutron-induced fission data in the intermediate energy region. In this Master's degree thesis, the fragment angular distribution from fission of 238 U, induced by 21-MeV neutrons, has been analysed from an experiment performed with the Medley/DIFFICILE setup at the The Svedberg Laboratory in Uppsala. The data have been corrected for low energy neutrons in the beam. The results agree with other experiments, as well as with model calculations. The data should be a starting point for further analysis with a goal to deduce the fission cross-section of 238 U

  18. Measurement of nuclide cross-sections of spallation residues in 1 A GeV 238U + proton collisions

    International Nuclear Information System (INIS)

    Taieb, J.; Tassan-Got, L.; Bernas, M.; Mustapha, B.; Rejmund, F.; Stephan, C.; Schmidt, K.H.; Armbruster, P.; Benlliure, J.; Enqvist, T.; Boudard, A.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W.; Casarejos, E.; Czajkowski, S.; Pravikoff, M.

    2003-02-01

    The production of heavy nuclides from the spallation-evaporation reaction of 238 U induced by 1 GeV protons was studied in inverse kinematics. The evaporation residues from tungsten to uranium were identified in-flight in mass and atomic number. Their production cross-sections and their momentum distributions were determined. The data are compared with empirical systematics. A comparison with previous results from the spallation of 208 Pb and 197 Au reveals the strong influence of fission in the spallation of 238 U. (orig.)

  19. 238U neutron-induced fission cross section for incident neutron energies between 5 eV and 3.5 MeV

    International Nuclear Information System (INIS)

    Difilippo, F.C.; Perez, R.B.; de Saussure, G.; Olsen, D.K.; Ingle, R.W.

    1979-01-01

    A measurement of the 238 U neutron-induced fission cross section was performed at the ORELA Linac facility in the neutron energy range between 5 eV and 3.5 MeV. The favorable signal-to-background ratio and high resolution of this experiment resulted in the identificaion of 85 subthreshold fission resonances or clusters of resonances in the neutron energy region between 5 eV and 200 keV. The fission data below 100 keV are characteristic of a weak coupling situation between Class I and Class II levels. The structure of the fission levels at the 720 eV and 1210 eV fission clusters is discussed. There is an apparent enhancement of the fission cross section at the opening of the 2 + neutron inelastic channel in 238 U at 45 keV. An enhancement of the subthreshold fission cross section between 100 keV and 200 keV is tentatively interpreted in terms of the presence of a Class II, partially damped vibrational level. There is a marked structure in the fission cross section above 200 keV up to and including the plateau between 2 and 3.5 MeV. 11 figures and 6 tables

  20. Angular distributions of target fragments from the reactions of 292 MeV - 25.2 GeV 12C with 197Au and 238U

    International Nuclear Information System (INIS)

    Morita, Y.

    1983-01-01

    The angular distributions of the 197 Au target fragments were all forwardly peaked. Extensively forward peaked angular distributions were observed at the non-relativistic projectile energies (292 MeV, 1.0 GeV). No obvious differences were observed in the angular distributions at the different relativistic projectile energies of 3.0 GeV, 12.0 GeV and 25.2 GeV. The characteristic angular distribution pattern from the relativistic projectile energy experiments was also observed in the non-relativistic energy experiments. Maximum degree of forward-peaking in the angular distributions at each projectile energy was observed at the product mass number (A) around 190 from the 292 MeV projectile energy, at A = 180 from 1.0 GeV and at A =175 from 3.0 GeV and 12.0 GeV. In general, two different types of angular distributions were observed in the relativistic projectile energy experiments with the 238 U target. Isotropic angular distributions were observed for the fission product nuclides. The angular distributions of the fission products at the intermediate (292 MeV) energy showed slightly forward peaked angular distributions. Because of the long projectile-target interaction time in the primary nuclear reaction, larger momentum was transferred from the projectile to the target nucleus. Steep forward-peaked angular distributions were also observed with the 238 U target

  1. Sequential fission process observed in the reaction (16.7 MeV/u) 238U + nat.Au using mica as dielectric track detector

    International Nuclear Information System (INIS)

    Shahzad, Muhammad Ikram; Qureshi, Imtinan Elahi; Manzoor, Shahid; Khan, Hameed Ahmed

    1999-01-01

    The evidence of sequential fission has been found in the heavy-ion reaction (16.7 MeV/u) 238 U + nat. Au, using muscovite mica as Dielectric Track Detector (DTD) placed in a 2π-geometry configuration. The reaction products originating from the interactions of 238 U ions with the atoms of gold were registered in the detector in the form of tracks and identified for performing a detailed kinematical analysis. For this purpose the spherical polar coordinates of the correlated tracks of the multipronged events have been analyzed on an event-by-event basis. Automatic, semi-automatic and manual measuring methods have been employed to collect and manipulate the track data. The known characteristics of binary and ternary events observed in the reaction have been used for the calibration of the detectors. The computed masses, Q-values and relative velocities of the reaction products determined in this analysis are compared with theoretical predictions based on sequential fission process. Agreement within one standard deviation with respect to the experimental values has been found for the majority of analyzed events. Therefore, it is concluded that three particles in the exit channel of the reaction are produced in two successive steps. In the first step of the reaction, two intermediate nuclei are formed as a result of an inelastic collision between projectile and target atoms while in the second step the fission of one of the intermediate nuclei of the previous step takes place. Furthermore no proximity effects have been observed

  2. Transfer of {sup 238}U, {sup 230}Th, {sup 226}Ra, and {sup 210}Pb from soils to tree and shrub species in a Mediterranean area

    Energy Technology Data Exchange (ETDEWEB)

    Blanco Rodriguez, P. [Natural Radioactivity Group, Facultad de Ciencias, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz (Spain); Vera Tome, F. [Natural Radioactivity Group, Facultad de Ciencias, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz (Spain)], E-mail: fvt@unex.es; Lozano, J.C. [Natural Radioactivity Group, Facultad de Ciencias, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz (Spain); Laboratorio de Radiaciones Ionizantes, Facultad de Ciencias, Universidad de Salamanca, 37008 Salamanca (Spain); Perez Fernandez, M.A. [Natural Radioactivity Group, Facultad de Ciencias, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz (Spain); Area de Ecologia, Universidad Pablo Olavide, Carretera de Utrera km. 1, 41013 Sevilla (Spain)

    2010-06-15

    The soil-to-plant transfer factors of natural uranium isotopes ({sup 238}U and {sup 234}U), {sup 230}Th, {sup 226}Ra, and {sup 210}Pb were studied in a disused uranium mine located in the Extremadura region in the south-west of Spain. The plant samples included trees (Quercus ilex, Quercus suber, and Eucalyptus cameldulensis) and one shrub (Cytisus multiflorus). All of them are characteristic of Mediterranean environments. The activity concentrations in leaves and fruit were determined for the tree species at different stages of growth. For the shrub, the total above-ground fraction was considered in three seasons. For old leaves and fruit, the highest activity concentrations were found in Eucalyptus cameldulensis for all the radionuclides studied, except in the case of {sup 230}Th that presented similar activity concentrations in all of the tree species studied. In every case, the transfer to fruit was less than the transfer to leaves. In the shrub, the results depended on the season of sampling, with the highest value obtained in spring and the lowest in autumn. Important correlations were obtained for {sup 238}U and {sup 226}Ra between the activity ratio in soils with that in leaves or fruit.

  3. Transfer of 238U, 230Th, 226Ra, and 210Pb from soils to tree and shrub species in a Mediterranean area

    International Nuclear Information System (INIS)

    Blanco Rodriguez, P.; Vera Tome, F.; Lozano, J.C.; Perez Fernandez, M.A.

    2010-01-01

    The soil-to-plant transfer factors of natural uranium isotopes ( 238 U and 234 U), 230 Th, 226 Ra, and 210 Pb were studied in a disused uranium mine located in the Extremadura region in the south-west of Spain. The plant samples included trees (Quercus ilex, Quercus suber, and Eucalyptus cameldulensis) and one shrub (Cytisus multiflorus). All of them are characteristic of Mediterranean environments. The activity concentrations in leaves and fruit were determined for the tree species at different stages of growth. For the shrub, the total above-ground fraction was considered in three seasons. For old leaves and fruit, the highest activity concentrations were found in Eucalyptus cameldulensis for all the radionuclides studied, except in the case of 230 Th that presented similar activity concentrations in all of the tree species studied. In every case, the transfer to fruit was less than the transfer to leaves. In the shrub, the results depended on the season of sampling, with the highest value obtained in spring and the lowest in autumn. Important correlations were obtained for 238 U and 226 Ra between the activity ratio in soils with that in leaves or fruit.

  4. Experimental and evaluated data on the discrete level excitation function of the 238U(n,n') reaction

    International Nuclear Information System (INIS)

    Simakov, S.P.

    1991-01-01

    Experimental data on the 238 U excitation function are compiled and analyzed. The experimental data are compared with the evaluated data from the BNAB, ENDF/B-IV and ENDL-78 evaluated data libraries. It is shown that the BNAB evaluated data are in good agreement with the existing experimental data, including new results from recent experiments. (author). 26 refs, 2 figs, 2 tabs

  5. Studies of projectile-like fragments in the 16O + 238U reaction at 20 MeV/u

    International Nuclear Information System (INIS)

    Dyer, P.; Awes, T.C.; Gelbke, C.K.; Back, B.B.; Mignerey, A.C.; Wolf, K.L.; Breuer, H.; Viola, V.E.; Meyer, W.G.

    1979-01-01

    Projectile residues were studied in coincidence with angle-correlated fission fragments resulting from reactions of 20-MeV/u 16 O ions on 238 U. Distributions of the missing parallel momentum are shown for different projectile residues, and the dependence of the average parallel recoil momentum on the average parallel momentum of the projectile residue is plotted. 2 figures

  6. Measurement of fast neutron induced fission cross sections of 232Th, 238U, 237Np and 243Am

    International Nuclear Information System (INIS)

    Kanda, Kazutaka; Sato, Osamu; Yoshida, Kazuo; Imaruoka, Hiromitsu; Terayama, Hiromichi; Yoshida, Masashi; Hirakawa, Naohiro

    1984-01-01

    Neutron induced fission cross sections of 232 Th, 238 U, 237 Np and 243 Am relative to 235 U were measured in the energy range from 1.5 to 6.6 MeV. The present results are compared with experimental results of others and evaluated data in JENDL-2 and ENDF/B-IV. (author)

  7. Anisotropy in angular distributions of 238U fission fragments by photons, produced in high energy electron interaction with Si monocrystal

    International Nuclear Information System (INIS)

    Kasilov, V.I.; Lapin, N.N.

    1981-01-01

    An enhancement is detected under the angle of 90 deg in the fission fragment yield from 238 U nuclei produced by photons emitted by high-energy electrons passing through a silicon monocrystal. The results enable one to select the most optimal conditions to obtain maximal yields of nuclear particles [ru

  8. Measurement of Fragment Mass Distributions in Neutron-induced Fission of 238U and 232Th at Intermediate Energies

    International Nuclear Information System (INIS)

    Simutkin, V.D.

    2008-01-01

    Conceptual analysis of accelerator-driven systems assumes extensive use of nuclear data on neutron-induced reactions at intermediate energies. In particular, information about the fission fragment yields from the 238 U(n,f) and 232 Th(n,f) reactions is of particular interest at neutron energies from 10 to 200 MeV. However, there is a lack of such data for both 238 U and 232 Th. Up to now, the intermediate energy measurements have been performed for 238 U only, and there are no data for the 232 Th(n,f) reaction. The aim of the work is to provide such data. Fission fragment mass distributions for the 232 Th(n,f) and 238 U(n,f) reactions have been measured for the incident neutron energies 32.8 MeV, 45.3 MeV and 59.9 MeV. The experiments have been performed at the neutron beam facility of the Universite Catholique de Louvain, Belgium. A multi-section Frisch-gridded ionization chamber has been used as a fission fragment detector. The data obtained have been interpreted in terms of the multimodal random neck-rupture model (MMRNRM). (authors)

  9. The effect of the 238U neutron strength function uncertainty on resonance structure calculations in unresolved regions

    International Nuclear Information System (INIS)

    Koshcheev, V.N.; Manturov, G.N.; Sinitsa, V.V.

    1991-01-01

    The effects of the neutron strength function uncertainties on the calculated values of the self-shielding factors and energy dependence of the total and capture 238 U cross-sections in the unresolved resonance region are investigated. (author). 26 refs, 5 figs

  10. Evaluation of daily intake of 238U and 232Th in a Korean mixed diet sample using RNAA

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Moon, Jong Hwa; Kim, Sun Ha; Park, Kwang Won; Kang, Sang Hoon; Cho, Seung Yeon

    2000-01-01

    To estimate the degree of intake of 238 U and 232 Th through daily diet, a Korean mixed diet sample was prepared after the investigation of the amount of consumption of the daily diet which corresponds to the age of 20 to 60 years. For the analysis of U and Th, the RNAA method was applied. Two standard reference materials were used for quality control and assurance and the analytical results were compared with a certified value. The determination of U and Th in the Korean mixed diet sample was carried out under the same analytical conditions and procedures with SRM. It is found that the concentration of U and Th in a Korean mixed diet was about 35.4 ppb and 3.4 ppb. From these results, the daily intake of 238 U and 232 Th by diet is evaluated to be 6.98 and 0.67 μg per day, respectively. Radioactivities related to the intake of 238 U and 232 Th were estimated to be about 86 mBq per person per day and the annual dose equivalents from 238 U and 232 Th revealed as 3.18 μSv and 0.29 μSv per person, respectively

  11. Influence of soil texture on the distribution and availability of 238U, 230Th, and 226Ra in soils

    International Nuclear Information System (INIS)

    Blanco Rodriguez, P.; Vera Tome, F.; Lozano, J.C.; Perez-Fernandez, M.A.

    2008-01-01

    The influence of soil texture on the distribution and availability of 238 U, 230 Th, and 226 Ra in soils was studied in soil samples collected at a rehabilitated uranium mine located in the Extremadura region in south-west Spain. The activity concentration (Bq kg -1 ) in the soils ranged from 60 to 750 for 238 U, from 60 to 260 for 230 Th, and from 70 to 330 for 226 Ra. The radionuclide distribution was determined in three soil fractions: coarse sand (0.5-2 mm), medium-fine sand (0.067-0.5 mm), and silt and clay ( 238 U, 230 Th, and 226 Ra between the activity concentration per fraction and the total activity concentration in the bulk soil. Thus, from the determination of the activity concentration in the bulk soil, one could estimate the activity concentration in each fraction. Correlations were also found for 238 U and 226 Ra between the labile activity concentration in each fraction and the total activity concentration in bulk soil. Assuming that there is some particle-size fraction that predominates in the process of soil-to-plant transfer, the parameters obtained in this study should be used as correction factors for the transfer factors determined from the bulk soil in previous studies

  12. Environmental control of U concentration and 234U/238U in speleothems at subannual resolution

    Science.gov (United States)

    Hu, C.; Henderson, G. M.

    2003-12-01

    Trace element and isotope variability in speleothems encodes a range of information about the past environment, although its interpretation is often problematic. U concentration and isotopes have frequently been analysed in speleothems in order to provide chronology, but their use as environmental proxies in their own right has not been comprehensively investigated. In this study, we have investigated the environmental controls of U in a stalagmite from the Central Yangtze Valley in China. This stalagmite grew rapidly throughout the Holocone and contains visible annual layers about 300microns thick. Analysis of a portion of the stalagmite corresponding to the 1970s by electron probe, LA-ICP-MS, and by physical subsampling indicate clear annual cycles in Sr/Ca, Mg/Ca, and Ba/Ca. The reasonably open cave structure and the correlation of Sr/Ca with Mg/Ca suggest that temperature exerts considerable control over these trace element variations. U/Ca also varies seasonally by up to 42 % and shows a clear anti-correlation with Mg/Ca (correlation coefficient -0.64). Based on the inverse relationship between U/Ca and temperature exhibited in other carbonates (e.g. corals) the speleothem U/Ca is suggested to be controlled primarily by temperature and may provide a paleo cave thermometer with less rainfall influence than Mg/Ca. Ongoing monitoring of the cave temperature and humidity will assess the robustness of this conclusion and the sensitivity of speleothem U/Ca to temperature. (234U/238U) in this stalagmite range from 1.733 to 1.872 during the Holocene. The U concentration is high enough (typically 0.48 ppm) and growth rate fast enough, that (234U/238U) can also be measured at a subannual resolution. The expected alpha-recoil control of excess 234U supply suggests that these measurements may provide a measure of the transit time of recharge waters to the stalagmite during the seasonal cycle. Such a proxy would enable deconvolution of temperature and recharge-rate control

  13. Contamination level of natural 238U and 232Th radionuclides in offshore of coal power plant (assessment at offshore of Panjang Island and Lada Bay, Banten)

    International Nuclear Information System (INIS)

    Sabam Parsaoran Situmorang; Harpasis Selamet Sanusi; June Mellawati

    2011-01-01

    This study had been carried out by collecting sample of the surficial sediments, sea water, seaweeds, anchovies (Stolephorus and Anchoa) and mussels (Codakia) from 4 locations in waters of Pulau Panjang and coastal of Lada Bay (as control/comparison site), Banten in June - July 2010. Natural radionuclides (Th) concentration in samples was measured using neutron activation analysis (NAA) method. The results showed that the total radionuclides concentration in sediment ( 238 U: 18.6160 - 35.0013 Bq/kg; 232 Th: 11.2020 - 35.6685 Bq/kg), seawater ( 238 U: undetected; 232 Th: 0.0790 - 0.1299 Bq/l), cultivation seaweeds ( 238 U: undetected; 232 Th: 3.6735 - 4.8345 Bq/kg), natural seaweeds ( 238 U: 3.6851 - 48.0430 Bq/kg; 232 Th: 3.9941 - 9.0788 Bq/kg), Stolephorus ( 238 U: undetected; 232 Th: 3.3078 Bq/kg) and Codakia ( 238 U: 6.8903 Bq/kg; 232 Th: 3.6023 Bq/kg) in Pulau Panjang, Banten around Suralaya coal power plant higher than control site that were around the Labuan coal power plant, namely in sediments ( 238 U: 10.4253 Bq/kg; 232 Th: 16.5952 Bq/kg), seawater( 238 U: undetected; 232 Th: 0.0671 Bq/l), cultivation seaweeds ( 238 U: undetected; 232 Th: 2.3005 Bq/kg), natural seaweeds ( 238 U: 19.5367 Bq/kg; 232 Th: 2.6729 Bq/kg) and Anchoa ( 238 U: undetected; 232 Th: 2.0603 Bq/kg). (author)

  14. EFFECTIVE SPECIFIC ACTIVITY OF NATURAL RADIONUCLIDES FOR THE NORM BELONGED TO 238U AND 232TH SERIES BEING IN THE STATE OF DISTURBED RADIOACTIVE EQUILIBRIUM

    Directory of Open Access Journals (Sweden)

    I. P. Stamat

    2008-01-01

    Full Text Available In the Sanitary Rules SR 2.6.1.1292-03 and SR 2.6.6.1169-02 classification of the industrial waste containing naturally occurring radioactive materials is adopted in accordance to the values of their effective specific activity Aeff. In a case of the disturbed equilibrium in 238U and 232Th series it is necessary to take into consideration actual contribution of the separate natural radionuclides of the mentioned series into the value of gamma dose rate of the waste. This will permit to avoid unjustified overestimating or understating of the waste category which prevents as unjustified expenditures on their treating so undertaking of the necessary measures providing radiation safety.

  15. High resolution photofission measurements in 238U and 232Th. Final report

    International Nuclear Information System (INIS)

    Lancman, H.

    1985-12-01

    A novel technique for measuring the photofission cross section with very high photon energy resolution has been developed. The photons are obtained from selected resonances in the (p,γ) reaction on various light nuclei. The photon energy resolution approaches 200 eV in favorable cases. The photon energy spread at each (p,γ) resonance is approx.20 keV on the average. Measurements of the photo-fission cross sections of 232 Th and 238 U have been carried out in the energy range from 5.8 to 12 MeV. Intermediate structure has been found in both nuclei at excitation energies around 6 MeV. Various properties of this structure, such as average areas of resonances, their spacing, width, and the underlying bakground, as well as the experimental fission probability averaged over the intermediate structure have been found to agree with theoretical predictions based on a double-humped fission barrier. In the case of 232 Th, the feature of this barrier, a rather high first hump and a deep secondary well, are quite different from those predicted by current theoretial barrier calculations. 13 refs., 4 figs., 3 tabs

  16. Bioaccumulation of uranium 234U and 238U in marine birds

    International Nuclear Information System (INIS)

    Borylo, A.; Skwarzec, B.

    2010-01-01

    In the paper was presented results of our study about uranium 234 U and 238 U radioactivity in the marine birds samples, collected in the Polish area of the southern Baltic Sea. We chose 11 species of sea birds: three species permanently residing at southern Baltic, four species of wintering birds and three species of migrating birds. The obtained results indicated that uranium is very irregularly distributed in organs and tissues of marine birds. The highest uranium content is characterized in liver, rest of viscera and feathers, the smallest in skin and muscles. The uranium concentration was higher for carnivorous species (long-tailed duck (C. hyemalis), common eider (S. mollissima), lower for species eating fish (great cormorant (P. carbo), common guillemot (U. aalge), red-throated diver (G. stellata) and razorbill (A. tarda)), but the biggest amounts for herbivorous species [tufted duck (A. fuligula) and eurasian coot (F. atra)]. About 63-67% of uranium, which was located in feathers of two species of marine birds: razorbill (A. tarda) and long-tailed duck (C. hymealis), was apparently adsorbed, which suggests that uranium adsorption on the feathers may be an important transfer from air to water. (author)

  17. Thermal flow in detectors of CNA-II with spontaneous fissions source of 238U

    International Nuclear Information System (INIS)

    Mascitti, J. A

    2012-01-01

    The thermal flux in the position of ex-core and in-core CNA-II Nuclear Power Plant (CNA-II) detectors is estimated considering neutron from the 238 U spontaneous fissions as the source, for the reactor cold state (isothermal state with both coolant and moderator at a temperature of 60 o C, a pressure of 35 ata and 15.46 ppm of natural Boron), and 24% inserted control rods (slightly sub-critical). Results are obtained for two different situations: with and without photo-neutrons due to the (γ,n) reaction in D 2 O. It is concluded that the thermal flux is under the detection limit of the boron trifluoride 104-SR or 282-IB detectors (≅10 -1 cm-2.s -1 ). These detectors are located in opposite positions in the inner concrete shielding, having the lowest detection limit among all ex-core detectors. A significant difference is verified in neutron fluxes between both cases, which suggest that photo-neutrons in large heavy water reactors such as CNA-II should not be ignored. The total neutron flux attenuation factor between the inner and outer region of the reactor pressure vessel was estimated to be 7.0 x 10 -7 . It should be mentioned that none of the results here presented has been affected by any correction factor. Each value has a percentage relative error representing the statistical uncertainty due to the probabilistic Monte Carlo method used to obtain it (author)

  18. 234U and 238U in the Carrizo Sandstone aquifer of South Texas

    International Nuclear Information System (INIS)

    Cowart, J.B.; Osmond, J.K.

    1974-01-01

    The waters of the Carrizo Sand formation of South Texas, United States of America, exhibit a pattern of uranium isotopic disequilibrium, described in terms of 234 U/ 238 U activity ratio ('A.R.') and uranium concentration, which may be a function of geochemical factors and the hydrologic history of the area. In terms of uranium, two regimes seem to exist. The first, including outcrop and near outcrop sample locations, has waters with relatively high concentration and low A.R. Somewhat downdip, the uranium concentration decreases sharply at the downdip limit of the oxidation environment, a zone of uranium precipitation. Recoil of daughter products from the precipitated uranium causes an increase of A.R. of the water. Water of low uranium concentration and high A.R. is found throughout the downdip regime. If a constant input of 234 U through time is assumed, the downdip decrease in A.R. after the initial introduction of 234 U into the water may be ascribed to radioactive decay of 234 U. However, this assumption leads to the calculation of a water flow rate one twentieth that determined by other means. Alternatively, this pattern may be an artifact of a change of climate from 20,000 years to 10,000 years ago. In this case, the decrease in A.R. downdip is a function of a varying input of 234 U as well as decay. (author)

  19. Space, energy and anisotropy effects on 238U effective capture cross sections in the resonance region

    International Nuclear Information System (INIS)

    Meftah, B.; Karam, R.A.

    1984-01-01

    Agreement between calculations and measurements within prescribed limits of error is always the test of engineering design analysis. Large and puzzling discrepancies do exist between several measured and calculated important integral reactor parameters. A thorough and exhaustive investigation of the methods used in reactor analysis revealed that in the generation of effective resonance cross sections no anisotropy effects are considered in the resonances. This is true in the integral transport and fundamental-mode codes. The neglect of anisotropy introduces errors at two levels: (1) the effective group cross sections such as σsub(c), σsub(f) and σsub(s); and (2) the diffusion coefficients and P 1 and higher components of the scattering cross sections. The study showed that the inclusion of linear scattering anisotropy increases, in general, the cell effective capture cross section of 238 U in both ZPR-6/5 and TRX-3 reactors. The increase was up to 2% in TRX-3 and 0.5% in ZPR-6/5. The effect on the multiplication factor was -0.003% Δk/k for ZPR-6/5 and -0.05% Δk/k for TRX-3. (author)

  20. Effect translational invariance in low-lying electric dipole excitations in 236U and 238U

    International Nuclear Information System (INIS)

    Ertugral, F.

    2005-01-01

    In this paper the translational invariant QRPA approach suggested by Pyatov [1] for the spherical nuclei has been extended to describe the 1 - states in deformed nuclei. The role of spurious centre-of-motion state on the Pygmy dipole resonance (PDR) has been investigated in the deformed 236 U and 238 U nuclei. It has been shown that the effect of taking into account the translational invariance of the Hamiltonians in the QRPA with separation of zero energy spurious solutions are noticeable in both the low energy density of 1 - states and in the PDR. Present investigation demonstrates the advantage of the translational invariant QRPA over the non translational invariant one. Within the translational invariant model the effect of removing spurious states on the E1 strength distribution is stronger than in none invariant QRPA (∼20%) for the states up to the neutron binding energy. It is found that the spurious state is spread over many levels, the largest admixture being situated in the region of the energy spacing between nuclear shells o w h . The giant resonance states contain, as a rule, very small admixtures of the spurious state

  1. Evaluation of correlating factors between 238U concentration measured in fine and course atmospheric particles

    International Nuclear Information System (INIS)

    Peixoto, Claudia Marques; Jacomino, Vanusa Maria Feliciano; Barreto, Alberto Avelar; Dias, Vagner Silva; Dias, Fabiana Ferrari

    2009-01-01

    Air quality is ever more important in function of the enormous proportion of human actions that have affected the environment over the last two centuries. Particulate material is one among many pollutants that can cause great risk to human health and the environment. It can be classified as: Total Suspended Particles (TSP), defined simply as particles with less than 50 μm aerodynamic diameter (one group of these particles can be inhaled and may cause health problems, while others may unfavorably affect the population's quality of life, interfering in environmental conditions and impairing normal community activities); and Inhalable Particles (PM 10 ), defined as those particles with less than 10 μm aerodynamic diameter. These particles penetrate the respiratory system and can reach pulmonary alveoli due to their small size, causing serious health damage. The Nuclear Technology Development Center (CDTN) has monitored air quality around its installations since 2000. CDTN's Environmental Monitoring Program (EMP) includes monitoring radioactivity levels contained in atmospheric TSP. In order to optimize its program, CDTN is carrying out a study to estimate the correlation between concentrations of particulate material measured in TSP and those measured in PM 10 , PI 2.5 and PI 1 , as well as determination of activity concentration for each controlled radionuclide in all parts. The objective of this study is to present preliminary results and report 238 U activity concentration results. (author)

  2. Short Lived Fission Product Yield Measurements in 235U, 238U and 239Pu

    Science.gov (United States)

    Silano, Jack; Tonchev, Anton; Tornow, Werner; Krishichayan, Fnu; Finch, Sean; Gooden, Matthew; Wilhelmy, Jerry

    2017-09-01

    Yields of short lived fission products (FPYs) with half lives of a few minutes to an hour contain a wealth of information about the fission process. Knowledge of short lived FPYs would contribute to existing data on longer lived FPY mass and charge distributions. Of particular interest are the relative yields between the ground states and isomeric states of FPYs since these isomeric ratios can be used to determine the angular momentum of the fragments. Over the past five years, a LLNL-TUNL-LANL collaboration has made precision measurements of FPYs from quasi-monoenergetic neutron induced fission of 235U, 238U and 239Pu. These efforts focused on longer lived FPYs, using a well characterized dual fission chamber and several days of neutron beam exposure. For the first time, this established technique will be applied to measuring short lived FPYs, with half lives of minutes to less than an hour. A feasibility study will be performed using irradiation times of < 1 hour, improving the sensitivity to short lived FPYs by limiting the buildup of long lived isotopes. Results from this exploratory study will be presented, and the implications for isomeric ratio measurements will be discussed. This work was performed under the auspices of US DOE by LLNL under Contract DE-AC52-07NA27344.

  3. Evaluating the distribution of the radioactive isotopes 226 Ra and 238 U in the ground water

    International Nuclear Information System (INIS)

    Bragea, M.

    2006-01-01

    By closing the mining activities huge quantities of waste rock stored in unprotected dump remained abandoned. As a result of the process of ore extraction, the waste rock and a very low percentage of metallic minerals were stored in tailing ponds, with a clay liner necessary to isolate the tailing from the rest of the aquifer. The migration of hazardous elements and radionuclides in groundwaters depends on the degree of their interaction with the surrounding rock material. This paper describes some of the experimental clay formations, to identify the main factors influencing the radioisotopes concentration and in a first approach to estimate the natural radionuclide intake levels by adult inhabitants of Ciudanovita region, Romania. Therefore we tried to study the extractive power of natural water in the existing depositing places. Several natural analogue laboratory models were set up, to study the dependence of washed quantity of radionuclides on the water amount washing the sample and mass of the samples. The effect of sorption on travel time was determined by comparing groundwater travel time (no sorption) with radionuclide travel time (includes sorption) The mechanism of releasing 226 Ra and 238 U from the minerals that compose the waste rock is influenced by the duration of the contact between the water and the waste rock, the composition of the water phase. Further on, the necessity of the paper is connected to the fact that the exchanges water-waste rock are complex processes, that depend on the environment conditions, each case can be a particular case. (author)

  4. Anomalies in the Charge Yields of Fission Fragments from the ^{238}U(n,f) Reaction.

    Science.gov (United States)

    Wilson, J N; Lebois, M; Qi, L; Amador-Celdran, P; Bleuel, D; Briz, J A; Carroll, R; Catford, W; De Witte, H; Doherty, D T; Eloirdi, R; Georgiev, G; Gottardo, A; Goasduff, A; Hadyńska-Klęk, K; Hauschild, K; Hess, H; Ingeberg, V; Konstantinopoulos, T; Ljungvall, J; Lopez-Martens, A; Lorusso, G; Lozeva, R; Lutter, R; Marini, P; Matea, I; Materna, T; Mathieu, L; Oberstedt, A; Oberstedt, S; Panebianco, S; Podolyák, Zs; Porta, A; Regan, P H; Reiter, P; Rezynkina, K; Rose, S J; Sahin, E; Seidlitz, M; Serot, O; Shearman, R; Siebeck, B; Siem, S; Smith, A G; Tveten, G M; Verney, D; Warr, N; Zeiser, F; Zielinska, M

    2017-06-02

    Fast-neutron-induced fission of ^{238}U at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency γ-ray spectrometer (MINIBALL) to an inverse-kinematics neutron source (LICORNE) to extract charge yields of fission fragments via γ-γ coincidence spectroscopy. Experimental data and fission models are compared and found to be in reasonable agreement for many nuclei; however, significant discrepancies of up to 600% are observed, particularly for isotopes of Sn and Mo. This indicates that these models significantly overestimate the standard 1 fission mode and suggests that spherical shell effects in the nascent fission fragments are less important for low-energy fast-neutron-induced fission than for thermal neutron-induced fission. This has consequences for understanding and modeling the fission process, for experimental nuclear structure studies of the most neutron-rich nuclei, for future energy applications (e.g., Generation IV reactors which use fast-neutron spectra), and for the reactor antineutrino anomaly.

  5. Developments in the modelling approach for radiological safety assessment of "2"3"8U-series radionuclides in waste disposal

    International Nuclear Information System (INIS)

    Perez-Sanchez, D.; Thorne, M.

    2014-01-01

    Human and environmental radiation exposures from sites or areas contaminated with radioactive substances need to be quantified as part of the risk assessment process and for developing long-term remediation strategies. In most radiological assessment models, simplistic, empirical ratios are used to simulate contaminant transfers between environmental compartments. These are favoured because they facilitate modelling. Their use, however, significantly increases the uncertainty of model predictions, because they do not account for the underlying processes that govern spatial and temporal variations in radionuclide concentrations. In relation to more explicit, process-based modelling, representation of the migration of radionuclides in the "2"3"8U decay series in soils and their uptake by plants is of interest in various contexts, including the disposal of radioactive wastes and the remediation of former sites of uranium mining and milling. The structures of models used to assess doses in the biosphere for long-term waste disposal assessments have not changed significantly in the last few years. Several aspects of the model representations of the biosphere are currently being debated in international forums, and these aspects would benefit from further investigation. The potential topics of interest include biogeochemical zonation of radionuclides in the sub-surface, caused by changes in the redox characteristics in response to a variable water table. It has been proposed that traditional model structures are not able to represent this aspect of the system adequately. Major improvements are needed to make models more process-based and capable of simulating the kinetics of contaminant transfers. A major challenge is to identify where the greatest advantages can be gained in reducing model uncertainty and understanding variability, developing criteria to identify if further research is required for parameterizing dynamic-mechanistic models, and identifying the level of

  6. Use of LabSOCS for determination of specific concentrations of {sup 40}K, {sup 238}U and {sup 232}Th in fertilizer samples; Uso de LabSOCS no calculo da eficiencia de detecao para determinacao da concentracao especifica de {sup 40}K, {sup 238}U e {sup 232}Th em amostras de fertilizantes

    Energy Technology Data Exchange (ETDEWEB)

    Garcez, Ricardo Washington Dutra; Lopes, Jose Marques; Silva, Ademir Xavier da, E-mail: rgarcez@con.ufrj.br, E-mail: marqueslopez@yahoo.com.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Domingues, Alessandro Mariano; Lima, Marco Frota, E-mail: slessandrodomingues@fisica.if.uff.br, E-mail: marcofrotalima@yahoo.com.br [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Biologia

    2015-07-01

    Use of fertilizer is an established practice worldwide to promote agricultural productivity increased without increasing the planted area, resulting in native forests protection and increase of the food availability. Some kinds of fertilizer have in their chemical composition some radionuclides due the origin of its feedstock, such as {sup 238}U, the {sup 232}Th, and their descendants, beyond {sup 40}K. Knowledge of the radioactivity levels in the environment is great importance to know the gamma radiation dose that the human being is exposed. For identification and quantitation of radionuclides, it was used gamma spectrometry where HPGe detector was used to obtain the spectra, and LabSOCS software for calculating the detection efficiency for each energy. The values of {sup 232}Th specific concentrations ranged from 4.1 to 368.1 Bq.Kg{sup -1} , the values of {sup 238}U specific concentrations ranged from 16.0 to 647.7 Bq.Kg{sup -1} and {sup 40}K specific concentrations ranged from 19.1 to 12713 Bq.Kg{sup -1} . Concentrations of values are consistent with those found in literature. (author)

  7. Application of the grey system theory for forecasting the content of 238U in soil near a uranium mine exhaust outlet

    International Nuclear Information System (INIS)

    Ye Yongjun; Ding Dexin; Li Xiangyang; Zhou Xinghuo; Liu Dong

    2008-01-01

    In order to forecast the content of 238 U in soil near a uranium mine exhaust outlet, a general GM(1,1) forecasting model was established based on grey system theory, analyzing association degree and residual error distinction. According to the measuring datum of the content of 238 U in soil near a uranium mine exhaust outlet from 2001 to 2006, used the model to forecast the content of 238 U in soil, The results show that the forecasting value agrees with the measuring results and the forecasting precision is higher; at the same time the content of 238 U in soil in 2007 is also forecasted based on the model, the relative error was 4.8%; which shows the GM(1,1) forecasting model has higher practical value, and is a effective method for forecasting the content of 238 U in soil near a uranium mine exhaust outlet. (authors)

  8. Seawater 234U/238U recorded by modern and fossil corals

    Science.gov (United States)

    Chutcharavan, Peter M.; Dutton, Andrea; Ellwood, Michael J.

    2018-03-01

    U-series dating of corals is a crucial tool for generating absolute chronologies of Late Quaternary sea-level change and calibrating the radiocarbon timescale. Unfortunately, coralline aragonite is susceptible to post-depositional alteration of its primary geochemistry. One screening technique used to identify unaltered corals relies on the back-calculation of initial 234U/238U activity (δ234Ui) at the time of coral growth and implicitly assumes that seawater δ234U has remained constant during the Late Quaternary. Here, we test this assumption using the most comprehensive compilation to date of coral U-series measurements. Unlike previous compilations, this study normalizes U-series measurements to the same decay constants and corrects for offsets in interlaboratory calibrations, thus reducing systematic biases between reported δ234U values. Using this approach, we reassess (a) the value of modern seawater δ234U, and (b) the evolution of seawater δ234U over the last deglaciation. Modern coral δ234U values (145.0 ± 1.5‰) agree with previous measurements of seawater and modern corals only once the data have been normalized. Additionally, fossil corals in the surface ocean display δ234Ui values that are ∼5-7‰ lower during the last glacial maximum regardless of site, taxon, or diagenetic setting. We conclude that physical weathering of U-bearing minerals exposed during ice sheet retreat drives the increase in δ234U observed in the oceans, a mechanism that is consistent with the interpretation of the seawater Pb-isotope signal over the same timescale.

  9. Evaluation of cross-section uncertainties using physical constraints for 238U, 239Pu

    International Nuclear Information System (INIS)

    De Saint Jean, Cyrille; Privas, Edwin; Archier, Pascal; Noguere, Gilles; Litaize, Olivier; Leconte, Pierre; Bernard, David

    2014-01-01

    Neutron-induced reactions between 0 eV and 20 MeV are based on various physical properties such as nuclear reaction models, microscopic and integral measurements. Most of the time, the evaluation work is done independently between the resolved resonance range and the continuum, giving rise to mismatches for the cross-sections, larger uncertainties on boundary and no cross-correlation between high-energy domain and resonance range. In addition the use of integral experiment is sometimes only related to central values (evaluation is 'working fine' on a dedicated set of benchmarks) and reductions of uncertainties are not straightforward on cross-sections themselves: working fine could be mathematically reflected by a reduced uncertainty. As the CIELO initiative is to bring experts in each field to propose/discuss these matters, after having presented the status of 238 U and 239 Pu cross-sections covariances evaluation (for JEFF-3.2 as well as the WPEC SG34 subgroup), this paper will present several methodologies that may be used to avoid such effects on covariances. A first idea based on the use of experiments overlapping two energy domains appeared in the near past. It was reviewed and extended to the use of systematic uncertainties (normalisation for example) and for integral experiments as well. In addition, we propose a methodology taking into account physical constraints on an overlapping energy domain where both nuclear reaction models are used (continuity of both cross-sections and derivatives for example). The use of Lagrange multiplier (related to these constraints) in a classical generalised least square procedure will be exposed. Some academic examples will then be presented for both point-wise and multi-group cross-sections to present the methodologies. In addition, new results for 239 Pu will be presented on resonance range and higher energies to reduce capture and fission cross-section uncertainties by using integral experiments (JEZEBEL experiment as

  10. Electromagnetic dissociation of 238U in heavy-ion collisions at 120 MeV/A

    International Nuclear Information System (INIS)

    Justice, M.L.

    1991-04-01

    This thesis describes a measurement of the heavy-ion induced electromagnetic dissociation of a 120 MeV/A 238 U beam incident on five targets: 9 Be, 27 Al, nat Cu, nat Ag, and nat U. Electromagnetic dissociation at this beam energy is essentially a two step process involving the excitation of a giant resonance followed by particle decay. At 120 MeV/A there is predicted to be a significant contribution of the giant quadrupole resonance to the EMD cross sections. The specific exit channel which was looked at was projectile fission. The two fission fragments were detected in coincidence by an array of solid-state ΔE-E detectors, allowing the changes of the fragments to be determined to within ± .5 units. The events were sorted on the basis of the sums of the fragments' charges, acceptance corrections were applied, and total cross sections for the most peripheral events were determined. Electromagnetic fission at the beam energy of this experiment always leads to a true charge sum of 92. Due to the imperfect resolution of the detectors, charge sums of 91 and 93 were included in order to account for all of the electromagnetic fission events. The experimentally observed cross sections are due to nuclear interaction processes as well as electromagnetic processes. Under the conditions of this experiment, the cross sections for the beryllium target are almost entirely due to nuclear processes. The nuclear cross sections for the other four targets were determined by extrapolation from the beryllium data using a geometrical scaling model. After subtraction of the nuclear cross sections, the resulting electromagnetic cross sections are compared to theoretical calculations based on the equivalent photon approximation. Systematic uncertainties are discussed and suggestions for improving the experiment are given

  11. Radionuclides (40K, 232Th and 238U) and Heavy Metals (Cr, Ni, Cu, Zn, As and Pb) Distribution Assessment at Renggam Landfill, Simpang Renggam, Johor, Malaysia

    Science.gov (United States)

    Zaidi, E.; FahrulRazi, MJ; Azhar, ATS; Hazreek, ZAM; Shakila, A.; Norshuhaila, MS; Omeje, M.

    2017-08-01

    The assessment of radioactivity levels and the distribution of heavy metals in soil samples at CEP Farm landfill, Renggam in Johor State was to determine the activity concentrations of naturally occurring radionuclides and heavy metal concentrations of this landfill. The background radiation was monitored to estimate the exposure level. The activity concentrations of radionuclides in soil samples were determined using HPGe gamma ray spectroscopy whereas the heavy metal concentration was measured using X-RF analysis. The mean exposure rate at the landfill site was 36.2±2.4 μR hr-1 and the annual effective dose rate at the landfill site was 3.19 ± 0.22 mSv yr-1. However, residential area has lower mean exposure dose rate of about 16.33±0.72 μR hr-1 and has an annual effective dose rate of 1.43±0.06 mSv yr-1 compared to landfill sites. The mean activity concentration of 40K, 238U and 232Th at landfill site were 239.95±15.89 Bq kg-1, 20.90±2.49 Bq kg-1 and 40.61±4.59 Bq kg-1, respectively. For heavy metal compositions, Cr, Ni and Cu have mean concentration of 232±10 ppm, 23±2 ppm, and 46±19 ppm, respectively. Whereas, Zn has concentration of 64±9 ppm and concentration of 12±1 ppm and 71±2 ppm was estimated for As and Pb respectively. The higher activity concentration of 40K down the slope through leaching process whereas the higher activity level of 238U content at the landfill site may be attributed to the soil disruption to local equilibrium.

  12. Comparison of measured and calculated 238U capture self-indication ratios from 4 to 10 keV

    International Nuclear Information System (INIS)

    Perez, R.B.; de Saussure, G.; Yang, J.T.; Munoz-Cobos, J.L.; Todd, J.H.

    1983-01-01

    From 4 keV to 149 keV the 238 U cross sections are represented in ENDF/B-V by unresolved-resonance parameters (URP). The purpose of this representation is to enable the calculation of resonance self-protection as a function of temperature and dilution. Since the URPs are not defined unambiguously by the cross-section data, it is important that the unresolved representation be tested with appropriate experiments, such as capture self-indication ratio (SIR) measurements. In this paper we compare 238 U capture SIR measurements in the 4- to 10-keV energy range with calculations done with ENDF/B-V and with recently published resolved resonance parameters

  13. Concentrations and biological availability of 238U and 230Th in the environs of a uranium milling operation

    International Nuclear Information System (INIS)

    Ibrahim, S.; Flot, S.; Whicker, F.W.

    1982-01-01

    This paper reports on a study whose objectives were to determine 238 U and 230 Th concentrations in soil and native plants from various sites around a conventional acid leach uranium milling operation in the Western US, and to estimate plant/soil concentration factors. Soil and vegetation samples were collected from exposed, weathered tailings; near the edge of a tailings pond; from a reclamation area; and at several native range background (control) locations. The results indicate that mean plant/soil concentration factors varied significantly among sites and between radionuclides, but no significant differences between plant groups were found. Concentration factors for 230 Th were greater than for 238 U for plants growing at the edge of the tailings pond. It is speculated that the lower concentration factors for uranium relative to thorium at this site may be due to the proportion of their contents in soil that is biologically available for plant uptake

  14. Measurement of the 235U/238U fission cross section ratio in the 235U fission neutron spectrum

    International Nuclear Information System (INIS)

    Azimi-Garakani, D.; Bagheri-Darbandi, M.

    1983-06-01

    Fission cross section ratio of 235 U to 238 U has been measured in the fast neutron field generated by the 235 U fission plate installed on the thermal column of the Tehran Research Reactor (TRR) with a Makrofol solid state nuclear track detector. The experiments were carried out with a set of total six enriched 235 U and depleted 238 U deposits with different masses and Makrofol films of 0.025mm and 0.060mm thicknesses. The chemically etched tracks were counted by an optical microscope. No significant differences were observed with the thin and the thick films. The results showed that the average fission cross section ratio is 3.83+-0.25. (author)

  15. Angular distribution of fragments from neutron-induced fission of {sup 238}U in the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Magnus

    2004-06-01

    Areas ranging from nuclear structure models to accelerator-driven systems benefit from improved neutron-induced fission data in the intermediate energy region. In this Master's degree thesis, the fragment angular distribution from fission of {sup 238}U, induced by 21-MeV neutrons, has been analysed from an experiment performed with the Medley/DIFFICILE setup at the The Svedberg Laboratory in Uppsala. The data have been corrected for low energy neutrons in the beam. The results agree with other experiments, as well as with model calculations. The data should be a starting point for further analysis with a goal to deduce the fission cross-section of {sup 238}U.

  16. Report to the 238U discrepancy task force on SIOB fits to the ORNL, CBNM, and JAERI transmission data

    International Nuclear Information System (INIS)

    Olsen, D.K.

    1984-05-01

    The computer code SIOB has been used to obtain least-squares simultaneous-sample shape fits to the recent 238 U transmission data of ORNL, CBNM, and JAERI over the energy regions 1460 to 1820 eV, 2470 to 2740 eV, and 3820 to 4000 eV. The fits indicate that much of the systematic discrepancy in the published neutron widths from these data arose in the data analysis procedure. Except for the 3820- to 4000-eV JAERI data, the systematic differences in the resulting neutron widths from the present widths are larger than those contained in any existing evaluation. These fits were performed as part of the work for the NEANDC ad hoc 238 U Discrepancy Task Force. 20 references

  17. 230Th/238U and 226Ra/230Th fractionation in young basaltic glasses from the East Pacific Rise

    International Nuclear Information System (INIS)

    Reinitz, I.; Turekian, K.K.

    1989-01-01

    Mid-ocean ridge basalt (MORB) glasses treated to remove manganese and iron oxyhydroxide coatings containing U and Th decay chain nuclides sequestered from the ambient aqueous environment show little fractionation of ( 230 Th) from ( 238 U), but extensive enrichment of ( 226 Ra) over ( 230 Th). Chronometry based on ( 230 Th)-( 238 U) disequilibrium yields a mean age of 151,000 ± 55,000 (2σ) years ago for Th-U fractionation, from a source region with Th/U (atom ratio) = 1.58 ± 0.43 (2σ). ( 226 Ra) excesses over ( 230 Th) indicate an enrichment event more recent than the fractionation of Th from U. ( 226 Ra/ 230 Th) correlates well with K/U, providing a rough means of estimating the age since eruption of MORB glasses. (orig.)

  18. Natural activities of 40K, 238U and 232Th in elephant grass (Pennisetum purpureum) in Ibadan metropolis, Nigeria

    International Nuclear Information System (INIS)

    Jibiri, N.N.; Ajao, A.O.

    2004-01-01

    Samples of elephant grass collected at some pasturing farmlands across different locations in Ibadan metropolis were analyzed for their natural radioactivity concentrations due to 40 K, 238 U and 232 Th radionuclides. Radioactivity measurements were carried out using γ-ray spectroscopy. The average radioactivity concentration of 40 K was found to be 64.5±8.1 Bq kg -1 , 25.7±5.5 Bq kg -1 for 238 U and 33.4±3.9 Bq kg -1 for 232 Th. The radiological health implication to the population that may result from these values is found to be very low and almost insignificant. No artificial radionuclide, however, was detected in any of the samples, hence, measurements have been taken as representing baseline values of these radionuclides in the grass in the metropolis

  19. Estimation of uncertainties in {sup 1}H, Zr and {sup 238}U nuclear data contained in JENDL-3.2

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Keiichi; Nakajima, Yutaka; Fukahori, Tokio; Chiba, Satoshi; Nakagawa, Tsuneo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kawano, Toshihiko

    1996-08-01

    Uncertainties have been estimated for the total, elastic scattering and capture cross sections of {sup 1}H, the capture, (n,2n) reaction and inelastic scattering cross sections of natural Zr, and the inelastic scattering cross sections and resolved resonance parameters of {sup 238}U. Considering the evaluation method taken for each data, standard deviations and correlation matrices were determined in 18 energy structure. (author). 50 refs.

  20. Estimation of uncertainties in resonance parameters of {sup 56}Fe, {sup 239}Pu, {sup 240}Pu and {sup 238}U

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Tsuneo; Shibata, Keiichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-05-01

    Uncertainties have been estimated for the resonance parameters of {sup 56}Fe, {sup 239}Pu, {sup 240}Pu and {sup 238}U contained in JENDL-3.2. Errors of the parameters were determined from the measurements which the evaluation was based on. The estimated errors have been compiled in the MF32 of the ENDF format. The numerical results are given in tables. (author)

  1. Triple-humped fission barrier model for a new {sup 238}U neutron cross-section evaluation and first validations

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Jimenez, M.J. [CEA/DIF/DPTA/Service de Physique Nucleaire, B.P. 12, F-91680 Bruyeres-le-Chatel (France); Morillon, B. [CEA/DIF/DPTA/Service de Physique Nucleaire, B.P. 12, F-91680 Bruyeres-le-Chatel (France); Romain, P. [CEA/DIF/DPTA/Service de Physique Nucleaire, B.P. 12, F-91680 Bruyeres-le-Chatel (France)]. E-mail: pascal.romain@cea.fr

    2005-01-15

    A new neutron-induced cross-section evaluation of {sup 238}U from 1 keV up to 200 MeV has been performed using only nuclear reactions models. A new fission penetrability model taking into account a triple humped barrier has been developed. A clear improvement has been observed for K-effective validation tests (up to 30 MeV) with this new evaluation. This improvement is mainly due to a better treatment of the inelastic exit channel.

  2. High-resolution photofission measurements in 238U and 232Th. Progress report, June 1, 1980-February 10, 1981

    International Nuclear Information System (INIS)

    Lancman, H.

    1981-02-01

    Intense proton beam currents from the Dynamitron at Brooklyn College have been used to generate gamma rays of variable energy from a number of (p,γ) resonances in various nuclei. Spectra of photofission fragments of 238 U and 232 Th have been measured with an average gamma ray energy resolution of approx. 300 eV. Structure in the photofission cross section of 232 Th was observed at approx. 6176 keV

  3. Projectile fission of 238U relativistic ions in a Pb target and discovery of new fission fragments

    International Nuclear Information System (INIS)

    Bernas, M.; Donzaud, C.; Dessagne, Ph.; Miehe, Ch.; Hanelt, E.; Heinz, A.

    1994-01-01

    With the 238 U beam accelerated at relativistic energies by the heavy ion synchrotron (SIS) at GSI, fission was investigated using inverse kinematics. This geometry is well suited for analyzing fragments with the fragment separator. The fragments are identified by in flight measurements of their energy loss and time of flight signals. More than forty new isotopes have been discovered focusing on the light branch of fission products. (K.A.) 12 refs., 5 figs., 1 tab

  4. Options for the deduction of target and intervention values for radon precursors of the 238U- and 232Th-series in soils

    International Nuclear Information System (INIS)

    Stoop, P.; Lembrechts, J.

    1993-04-01

    Radiation protection policy in the Netherlands applies to human activities in which ionizing radiation presents a hazard, not to naturally occurring sources of radiation. The risk levels (maximum permissible risk and negligible risk) apply to sources of radiation that cause an additional risk. Translation of these levels into practical environmental quality objectives therefore implies that both the extent and the origin of the risk are determined. The distinction between the natural and the additional radiation dose is of particular interest. In this report various possibilities are described for measuring, explaining and predicting the naturally occurring concentrations of the precursors of the element radon in the two radioactive decay series starting with 238 U and 232 Th. Several methods are given that may be used to derive environmental quality objectives for the soil with respect to these radionuclides. These environmental quality objectives are an important basis for among other things the soil sanitation policy. The nature of the radionuclides considered may have consequences for the choice of sanitation techniques. Because possible sources and cases of soil pollution may have important consequences for the Dutch policy on soil sanitation, a short overview is given of data published on these subjects. The foundation and the control of intervention levels requires insight in the relative importance of pollution pathways. As a result, pathways have been given ample attention. 9 figs., 17 tabs., 66 refs

  5. Sequential fission process observed in the reaction (16.7 MeV/u) {sup 238}U + {sup nat.}Au using mica as dielectric track detector

    Energy Technology Data Exchange (ETDEWEB)

    Shahzad, Muhammad Ikram; Qureshi, Imtinan Elahi; Manzoor, Shahid; Khan, Hameed Ahmed

    1999-01-04

    The evidence of sequential fission has been found in the heavy-ion reaction (16.7 MeV/u) {sup 238}U + {sup nat.}Au, using muscovite mica as Dielectric Track Detector (DTD) placed in a 2{pi}-geometry configuration. The reaction products originating from the interactions of {sup 238}U ions with the atoms of gold were registered in the detector in the form of tracks and identified for performing a detailed kinematical analysis. For this purpose the spherical polar coordinates of the correlated tracks of the multipronged events have been analyzed on an event-by-event basis. Automatic, semi-automatic and manual measuring methods have been employed to collect and manipulate the track data. The known characteristics of binary and ternary events observed in the reaction have been used for the calibration of the detectors. The computed masses, Q-values and relative velocities of the reaction products determined in this analysis are compared with theoretical predictions based on sequential fission process. Agreement within one standard deviation with respect to the experimental values has been found for the majority of analyzed events. Therefore, it is concluded that three particles in the exit channel of the reaction are produced in two successive steps. In the first step of the reaction, two intermediate nuclei are formed as a result of an inelastic collision between projectile and target atoms while in the second step the fission of one of the intermediate nuclei of the previous step takes place. Furthermore no proximity effects have been observed.

  6. Depth profiling of residual activity of ^{237}U fragments as a range verification technique for ^{238}U primary ion beam

    Directory of Open Access Journals (Sweden)

    I. Strašík

    2012-07-01

    Full Text Available Experimental and simulation data concerning fragmentation of ^{238}U ion beam in aluminum, copper, and stainless-steel targets with the initial energy 500 and 950  MeV/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 ^{237}U isotope that has a range very close to the range of the primary ^{238}U ions. Therefore, the depth profiling of the ^{237}U isotope can be utilized for experimental verification of the ^{238}U 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.

  7. Investigation of fission properties and evaporation residue measurement in the reactions using 238U target nucleus

    Directory of Open Access Journals (Sweden)

    Saro S.

    2011-10-01

    Full Text Available Fragment mass distributions for fission after full momentum transfer were measured in the reactions of 30Si,34,36 S,31P,40Ar + 238U at bombarding energies around the Coulomb barrier. Mass distributions change significantly as a function of incident beam energy. The asymmetric fission probability increases at sub-barrier energy. The phenomenon is interpreted as an enhanced quasifission probability owing to orientation effects on fusion and/or quasifission. The evaporation residue (ER cross sections were measured in the reactions of 30Si + 238U and 34S + 238U to obtain information on fusion. In the latter reaction, significant suppression of fusion was implied. This suggests that fission events different from compound nucleus are included in the masssymmetric fragments. The results are supported by a model calculation based on a dynamical calculation using Langevin equation, in which the mass distribution for fusion-fission and quasifission fragments are separately determined.

  8. Dynamics of Db isotopes formed in reactions induced by 238U, 248Cm, and 249Bk across the Coulomb barrier

    Science.gov (United States)

    Kaur, Gurjit; Sandhu, Kirandeep; Kaur, Amandeep; Sharma, Manoj K.

    2018-05-01

    The dynamical cluster decay model is employed to investigate the decay of *265Db and *267Db nuclei, formed in the 27Al+238U , 18O+249Bk , and 19F+248Cm hot fusion reactions at energies around the Coulomb barrier. First, the fission dynamics of the 27Al+238U reaction is explored by investigating the fragmentation and preformation yield of the reaction. The symmetric mass distribution of the fission fragments is observed for *265Db nucleus, when static β2 i deformations are used within hot optimum orientation approach. However, the mass split gets broaden for the use of β2 i-dynamical hot configuration of the fragments and becomes clearly asymmetric for the cold-static-deformed approach. Within the application of cold orientations of fragments, a new fission channel is observed at mass asymmetry η =0.29 . In addition to 238U-induced reaction, the work is carried out to address the fission and neutron evaporation cross sections of *267Db nucleus formed via 19F+248Cm and 18O+249Bk reactions, besides a comprehensive analysis of fusion and capture processes. Higher fusion cross sections and compound nucleus formation probabilities (PCN) are obtained for the 18O+249Bk reaction, as larger mass asymmetry in the entrance channel leads to reduced Coulomb factor. Finally, the role of sticking (IS) and nonsticking (INS) moments of inertia is analyzed for the 4 n and 5 n channels of *267Db nuclear system.

  9. Comparison of the simulated diffusion of 238U and 234U isotopes with profile data from granite fractures

    International Nuclear Information System (INIS)

    Latham, A.G.

    1991-01-01

    The observed profiles of uranium content and 234 U/ 238 U activity ratios as they vary with distance into the rock at a granite fracture wall have been interpreted using a simple diffusion-sorption model. For simplicity, the model assumes a linear reversible isotherm. Using simple constraints, it has been possible to estimate long-term values appropriate for the distribution coefficient, K d for uranium in granite. A potential constraint on the uranium K d value is provided by the 234 U/ 238 U activity ratio variations. However, natural 234 U/ 238 U activity ratios seldom change monotonically with distance and it is suspected that they are the result, to some extent, of later uranium removal. To take this approach further, corresponding physical rock property data and closer sampling in the fracture profiles would be required. Estimates of K d are in the range 0.1 to 10 m 3 kg -1 , and are in agreement with the upper part of the range obtained from laboratory experiments. (author)

  10. Solubility of 238U radionuclide from various types of soil in synthetic gastrointestinal fluids using “US in vitro” digestion method

    International Nuclear Information System (INIS)

    Rashid, Nur Shahidah Abdul; Sarmani, Sukiman; Majid, Amran Ab.; Mohamed, Faizal; Siong, Khoo Kok

    2015-01-01

    238U radionuclide is a naturally occuring radioactive material that can be found in soil. In this study, the solubility of 238U radionuclide obtained from various types of soil in synthetic gastrointestinal fluids was analysed by “US P in vitro” digestion method. The synthetic gastrointestinal fluids were added to the samples with well-ordered, mixed throughly and incubated according to the human physiology digestive system. The concentration of 238U radionuclide in the solutions extracted from the soil was measured using Induced Coupling Plasma Mass Spectrometer (ICP-MS). The concentration of 238U radionuclide from the soil samples in synthetic gastrointestinal fluids showed different values due to different homogenity of soil types and chemical reaction of 238U radionuclide. In general, the solubility of 238U radionuclide in gastric fluid was higher (0.050 – 0.209 ppm) than gastrointestinal fluids (0.024 – 0.050 ppm). It could be concluded that the US P in vitro digestion method is practicle for estimating the solubility of 238U radionuclide from soil materials and could be useful for monitoring and risk assessment purposes applying to environmental, health and contaminated soil samples

  11. Solubility of {sup 238}U radionuclide from various types of soil in synthetic gastrointestinal fluids using “US in vitro” digestion method

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Nur Shahidah Abdul; Sarmani, Sukiman; Majid, Amran Ab.; Mohamed, Faizal; Siong, Khoo Kok, E-mail: khoo@ukm.edu.my [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2015-04-29

    238U radionuclide is a naturally occuring radioactive material that can be found in soil. In this study, the solubility of 238U radionuclide obtained from various types of soil in synthetic gastrointestinal fluids was analysed by “US P in vitro” digestion method. The synthetic gastrointestinal fluids were added to the samples with well-ordered, mixed throughly and incubated according to the human physiology digestive system. The concentration of 238U radionuclide in the solutions extracted from the soil was measured using Induced Coupling Plasma Mass Spectrometer (ICP-MS). The concentration of 238U radionuclide from the soil samples in synthetic gastrointestinal fluids showed different values due to different homogenity of soil types and chemical reaction of 238U radionuclide. In general, the solubility of 238U radionuclide in gastric fluid was higher (0.050 – 0.209 ppm) than gastrointestinal fluids (0.024 – 0.050 ppm). It could be concluded that the US P in vitro digestion method is practicle for estimating the solubility of 238U radionuclide from soil materials and could be useful for monitoring and risk assessment purposes applying to environmental, health and contaminated soil samples.

  12. Sorption study of 226Ra(II) et 238U(VI) on to peat organic matter, in mining environment

    International Nuclear Information System (INIS)

    Bordelet, Gabrielle

    2014-01-01

    The environmental footprint of former uranium mining sites is a major concern for society. In order to guarantee the protection of ecosystems and thus a minimal radiological impact on the biosphere, it is important to understand and to be able to model the phenomena controlling the migration of uranium and its decay products, specially radium ( 226 Ra) (AREVA's Envir-at-Mines project). In the environment, among solid phases which can retain 238 U(VI) and 226 Ra(II), peat is known to have relevant affinity for U(VI). Because peat is usually composed at 90% dry weight of organic matter, the aim of this study was to qualify and quantify peat organic matter affinity for 238 U(VI) and 226 Ra(II). Peat samples extracted from Les Sagnes (close to a former uranium mining site in Limousin area, France) was characterised and batch adsorption/desorption experiments were conducted. The results indicate that 226 Ra(II) adsorption onto that peat is higher than 97% for pH ≥ 4-6 (depending on the organic/mineral ratio in dry peat) corresponding to K d values about 4500 ± 500 mL/g and 238 U(VI) adsorption is higher than 80% at pH ≥ 3 with K d maximal values reaching 11000 mL/g around pH 4.5. Only a little desorption was measured after one month. An ion exchange modelling for radium adsorption onto one type of organic matter sorption site was enough to fit the experimental adsorption K d for the peat over the whole range of pH. However, uranium sorption on peat can be modelled on that organic sorption site only from pH 1 to 5. From pH 5 to 10, to explain the experimental uranium adsorption K d values (close to 1500 mL/g), uranium sorption onto mineral phases (such as smectite and iron oxide in this study) has to be considered. An operational data set is given for both 238 U(VI) and 226 Ra(II) sorption onto Les Sagnes peat. Unlike usual peat, peat from Les Sagnes contains more than 10% dry weight of mineral matter. That is why it is necessary to model sorption of those two

  13. Using 238U/235U ratios to understand the formation and oxidation of reduced uranium solids in naturally reduced zones

    Science.gov (United States)

    Jemison, N.; Johnson, T. M.; Druhan, J. L.; Davis, J. A.

    2016-12-01

    Uranium occurs in groundwater primarily as soluble and mobile U(VI), which can be reduced to immobile U(IV), often observed in sediments as uraninite. Numerous U(VI)-contaminated sites, such as the DOE field site in Rifle, CO, contain naturally reduced zones (NRZ's) that have relatively high concentrations of organic matter. Reduction of heavy metals occurs within NRZ's, producing elevated concentrations of iron sulfides and U(IV). Slow, natural oxidation of U(IV) from NRZ's may prolong U(VI) contamination of groundwater. The reduction of U(VI) produces U(IV) with a higher 238U/235U ratio. Samples from two NRZ sediment cores recovered from the Rifle site revealed that the outer fringes of the NRZ contain U(IV) with a high 238U/235U ratio, while lower values are observed in the center . We suggest that as aqueous U(VI) was reduced in the NRZ, it was driven to lower 238U/235U values, such that U(IV) formed in the core of the NRZ reflects a lower 238U/235U. Two oxidation experiments were conducted by injecting groundwater containing between 14.9 and 21.2 mg/L dissolved O2 as an oxidant into the NRZ. The oxidation of U(IV) from this NRZ increased aqueous U(VI) concentrations and caused a shift to higher 238U/235U in groundwater as U(IV) was oxidized primarily on the outer fringes of the NRZ. In total these observations suggest that the stability of solid phase uranium is governed by coupled reaction and transport processes. To better understand various reactive transport scenarios we developed a model for the formation and oxidation of NRZ's utilizing the reactive transport software CrunchTope. These simulations suggest that the development of isotopically heterogeneous U(IV) within NRZ's is largely controlled by permeability of the NRZ and the U(VI) reduction rate. Oxidation of U(IV) from the NRZ's is constrained by the oxidation rate of U(IV) as well as iron sulfides, which can prevent oxidation of U(IV) by scavenging dissolved oxygen.

  14. Radiation characteristics of helical tomotherapy

    International Nuclear Information System (INIS)

    Jeraj, Robert; Mackie, Thomas R.; Balog, John; Olivera, Gustavo; Pearson, Dave; Kapatoes, Jeff; Ruchala, Ken; Reckwerdt, Paul

    2004-01-01

    Helical tomotherapy is a dedicated intensity modulated radiation therapy (IMRT) system with on-board imaging capability (MVCT) and therefore differs from conventional treatment units. Different design goals resulted in some distinctive radiation field characteristics. The most significant differences in the design are the lack of flattening filter, increased shielding of the collimators, treatment and imaging operation modes and narrow fan beam delivery. Radiation characteristics of the helical tomotherapy system, sensitivity studies of various incident electron beam parameters and radiation safety analyses are presented here. It was determined that the photon beam energy spectrum of helical tomotherapy is similar to that of more conventional radiation treatment units. The two operational modes of the system result in different nominal energies of the incident electron beam with approximately 6 MeV and 3.5 MeV in the treatment and imaging modes, respectively. The off-axis mean energy dependence is much lower than in conventional radiotherapy units with less than 5% variation across the field, which is the consequence of the absent flattening filter. For the same reason the transverse profile exhibits the characteristic conical shape resulting in a 2-fold increase of the beam intensity in the center. The radiation leakage outside the field was found to be negligible at less than 0.05% because of the increased shielding of the collimators. At this level the in-field scattering is a dominant source of the radiation outside the field and thus a narrow field treatment does not result in the increased leakage. The sensitivity studies showed increased sensitivity on the incident electron position because of the narrow fan beam delivery and high sensitivity on the incident electron energy, as common to other treatment systems. All in all, it was determined that helical tomotherapy is a system with some unique radiation characteristics, which have been to a large extent

  15. Measurement of the 234U/238U activity ratios in the organs and internal tissues of a domestic goat kid (Capra aegagrus hircus)

    International Nuclear Information System (INIS)

    Francesco De Santis; Massimo Esposito

    2015-01-01

    In this paper, we compare the 234 U/ 238 U activity ratios (ARs) in various internal tissues and organs of a goat kid with the ingested 234 U/ 238 U AR to assess isotopic fractionation. The results obtained from soft tissues (i.e., the kidneys, liver, lung, and bladder) that undergo indirect assimilation of uranium from the feed through the bloodstream suggest an increase in the 234 U/ 238 U AR. In contrast, the intestine, bones and feces had the same AR values as the feed. Finally, we broadly assess uranium transfer from the feed to the animal based on the concentration ratio and the feed transfer coefficient. (author)

  16. Uranium ("2"3"8U)-induced ROS and cell cycle perturbations, antioxidant responses and erythrocyte nuclear abnormalities in the freshwater iridescent shark fish Pangasius sutchi

    International Nuclear Information System (INIS)

    Annamalai, Sathesh Kumar; Arunachalam, Kantha Deivi

    2017-01-01

    Highlights: • Exposure to "2"3"8U deteriorated the antioxidant defenses like SOD, CAT and LPO. • Flow cytometric analysis revealed the increase in G2/M phase and S phase. • Micronucleus frequencies increased with Increased "2"3"8U exposure and time. • Exposure to waterborne "2"3"8U induces both chemical and radiotoxicity in P. sutchi. • ROS-mediated "2"3"8U toxic mechanism and the antioxidant responses has been proposed. - Abstract: The strategic plan of this study is to analyze any possible radiological impact on aquatic organisms from forthcoming uranium mining facilities around the Nagarjuna Sagar Dam in the future. The predominantly consumed and dominant fish species Pangasius sutchi, which is available year-round at Nagarjuna Sagar Dam, was selected for the study. To comprehend the outcome and to understand the mode of action of "2"3"8U, the fish species Pangasius sutchi was exposed to ¼ and ½ of the LC_5_0 doses of waterborne "2"3"8U in a static system in duplicate for 21 days. Blood and organs, including the gills, liver, brain and muscles, were collected at different time periods—0 h, 24 h, 48 h, 72 h, 96 h, 7, days 14 days and 21 days—using ICP-MS to determine the toxic effects of uranium and the accumulation of "2"3"8U concentrations. The bioaccumulation of "2"3"8U in P. sutchi tissues was dependent on exposure time and concentration. The accumulation of uranium was, in order of magnitude, measured as gills > liver > brain > tissue, with the highest accumulation in the gills. It was observed that exposure to "2"3"8U significantly reduced antioxidant enzymes such as superoxide dismutase, catalase, and lipid peroxidase. The analysis of DNA fragmentation by comet assay and cell viability by flow cytometry was performed at different time intervals. DNA histograms by flow cytometry analysis revealed an increase in the G2/M phase and the S phase. The long-term "2"3"8U exposure studies in fish showed increasing micronucleus frequencies in erythrocytes with greater exposure time. The higher the concentration of "2"3"8U is, the greater is the effect observed, suggesting a close relationship between accumulation and toxicity. A possible ROS-mediated "2"3"8U toxicity mechanism and antioxidant responses have been proposed.

  17. Uranium ({sup 238}U)-induced ROS and cell cycle perturbations, antioxidant responses and erythrocyte nuclear abnormalities in the freshwater iridescent shark fish Pangasius sutchi

    Energy Technology Data Exchange (ETDEWEB)

    Annamalai, Sathesh Kumar; Arunachalam, Kantha Deivi, E-mail: kanthad.arunachalam@gmail.com

    2017-05-15

    Highlights: • Exposure to {sup 238}U deteriorated the antioxidant defenses like SOD, CAT and LPO. • Flow cytometric analysis revealed the increase in G2/M phase and S phase. • Micronucleus frequencies increased with Increased {sup 238}U exposure and time. • Exposure to waterborne {sup 238}U induces both chemical and radiotoxicity in P. sutchi. • ROS-mediated {sup 238}U toxic mechanism and the antioxidant responses has been proposed. - Abstract: The strategic plan of this study is to analyze any possible radiological impact on aquatic organisms from forthcoming uranium mining facilities around the Nagarjuna Sagar Dam in the future. The predominantly consumed and dominant fish species Pangasius sutchi, which is available year-round at Nagarjuna Sagar Dam, was selected for the study. To comprehend the outcome and to understand the mode of action of {sup 238}U, the fish species Pangasius sutchi was exposed to ¼ and ½ of the LC{sub 50} doses of waterborne {sup 238}U in a static system in duplicate for 21 days. Blood and organs, including the gills, liver, brain and muscles, were collected at different time periods—0 h, 24 h, 48 h, 72 h, 96 h, 7, days 14 days and 21 days—using ICP-MS to determine the toxic effects of uranium and the accumulation of {sup 238}U concentrations. The bioaccumulation of {sup 238}U in P. sutchi tissues was dependent on exposure time and concentration. The accumulation of uranium was, in order of magnitude, measured as gills > liver > brain > tissue, with the highest accumulation in the gills. It was observed that exposure to {sup 238}U significantly reduced antioxidant enzymes such as superoxide dismutase, catalase, and lipid peroxidase. The analysis of DNA fragmentation by comet assay and cell viability by flow cytometry was performed at different time intervals. DNA histograms by flow cytometry analysis revealed an increase in the G2/M phase and the S phase. The long-term {sup 238}U exposure studies in fish showed increasing

  18. High energy resolution measurement of the 238U neutron capture yield in the energy region between 1 and 100 keV

    International Nuclear Information System (INIS)

    Machlin, R.L.; Perez, R.B.; de Saussure, G.; Ingle, R.W.

    1988-01-01

    A measurement of the 238 U neutron capture yield was performed at the 150 meter flight-path of the ORELA facility on two 238 U samples (0.01224 and 0.0031 atomsbarn). The capture yeild data were normalized by Moxon's small resonance method. The energy resolution achieved in this measurement frequently resulted in doublet and triplet splittings of what appeared to be single resonance in previous measurements. This resolution should allow extension of the resolved resonance energy region in 238 U from the present 4-keV limit up to 15 or 20 keV incident neutron energy. Some 200 small resonances of the ( 238 U /plus/ n) compound nucleus have been observed which had not been detected in transmission measurement, in the energy range from 250 eV to 10 keV

  19. Isotopic production cross-sections and recoil velocities of spallation-fission fragments in the reaction 238U(1A GeV)+e

    CERN Document Server

    Pereira, J; Wlazlo, W; Benlliure, J; Casarejos, E; Armbruster, P; Bernas, M; Enqvist, T; Legrain, R; Leray, S; Rejmund, F; Mustapha, B; Schmidt, K.-H; Stéphan, C; Taïeb, J; Tassan-Got, L; Volant, C; Boudard, A; Czajkowski, S; 10.1103/PhysRevC.75.014602

    2007-01-01

    Fission fragments of 1A GeV 238U nuclei interacting with a deuterium target have been investigatedwith the Fragment Separator (FRS) at GSI (Darmstadt) by measuring their isotopicproduction cross-sections and recoil velocities. The results, along with those obtained recently forspallation-evaporation fragments, provide a comprehensive analysis of the spallation nuclear productionsin the reaction 238U(1A GeV)+d. Details about experiment performance, data reductionand results will be presented.

  20. Dietary 232Th and 238U intakes for Japanese as obtained in a market basket study and contributions of imported foods to internal doses

    International Nuclear Information System (INIS)

    Shiraishi, K.

    1995-01-01

    Thorium-232 and 238 U contents in four food groups were measured by inductively coupled plasma mass spectrometry (ICP-MS). Daily intakes of 232 Th and 238 U for Japanese were estimated to 2.22 mBq and 15.5 mBq per person, respectively. Furthermore, preliminary estimations were made for the effects of imported foods on internal exposures for Japanese. (author). 16 refs., 1 fig., 3 tabs

  1. Measurement of double differential cross sections of secondary neutrons from 238U, 209Bi, Fe and 9Be around 10 MeV

    International Nuclear Information System (INIS)

    Qi Bujia; Tang Hongqing; Zhou Zuying

    1995-01-01

    Double differential cross sections of 238 U, 209 Bi, Fe and 9 Be around 10 MeV are measured at 5 or 6 or 8 angles between 35 degree and 120 degree by means of both normal and abnormal TOF spectrometers using T(d,n) neutron source. The present result of 9 Be is compared with existing experimental data. The data of 238 U and 209 Bi are compared with theoretical calculations. A good agreement is achieved

  2. Experimental Cross Sections for Reactions of Heavy Ions and 208Pb, 209Bi, 238U, and 248Cm Targets

    International Nuclear Information System (INIS)

    Patin, Joshua B.

    2002-01-01

    The study of the reactions between heavy ions and 208 Pb, 209 Bi, 238 U, and 248 Cm targets was performed to look at the differences between the cross sections of hot and cold fusion reactions. Experimental cross sections were compared with predictions from statistical computer codes to evaluate the effectiveness of the computer code in predicting production cross sections. Hot fusion reactions were studied with the MG system, catcher foil techniques and the Berkeley Gas-filled Separator (BGS). 3n- and 4n-exit channel production cross sections were obtained for the 238 U( 18 O,xn) 256-x Fm, 238 U( 22 Ne,xn) 260-x No, and 248 Cm( 15 N,xn) 263-x Lr reactions and are similar to previous experimental results. The experimental cross sections were accurately modeled by the predictions of the HIVAP code using the Reisdorf and Schaedel parameters and are consistent with the existing systematics of 4n exit channel reaction products. Cold fusion reactions were examined using the BGS. The 208 Pb( 48 Ca,xn) 256-x No, 208 Pb( 50 Ti,xn) 258-x Rf, 208 Pb( 51 V,xn) 259-x Db, 209 Bi( 50 Ti,xn) 259-x Db, and 209 Bi( 51 V,xn) 260-x Sg reactions were studied. The experimental production cross sections are in agreement with the results observed in previous experiments. It was necessary to slightly alter the Reisdorf and Schaedel parameters for use in the HIVAP code in order to more accurately model the experimental data. The cold fusion experimental results are in agreement with current 1n- and 2n-exit channel systematics

  3. 238U-230Th dating of chevkinite in high-silica rhyolites from La Primavera and Yellowstone calderas

    Science.gov (United States)

    Vazquez, Jorge A.; Velasco, Noel O.; Schmitt, Axel K.; Bleick, Heather A.; Stelten, Mark E.

    2014-01-01

    Application of 238U-230Th disequilibrium dating of accessory minerals with contrasting stabilities and compositions can provide a unique perspective on magmatic evolution by placing the thermochemical evolution of magma within the framework of absolute time. Chevkinite, a Th-rich accessory mineral that occurs in peralkaline and metaluminous rhyolites, may be particularly useful as a chronometer of crystallization and differentiation because its composition may reflect the chemical changes of its host melt. Ion microprobe 128U-230Th dating of single chevkinite microphenocrysts from pre- and post-caldera La Primavera, Mexico, rhyolites yields model crystallization ages that are within 10's of k.y. of their corresponding K-Ar ages of ca. 125 ka to 85 ka, while chevkinite microphenocrysts from a post-caldera Yellowstone, USA, rhyolite yield a range of ages from ca. 110 ka to 250 ka, which is indistinguishable from the age distribution of coexisting zircon. Internal chevkinite-zircon isochrons from La Primavera yield Pleistocene ages with ~5% precision due to the nearly two order difference in Th/U between both minerals. Coupling chevkinite 238U-230Th ages and compositional analyses reveals a secular trend of Th/U and rare earth elements recorded in Yellowstone rhyolite, likely reflecting progressive compositional evolution of host magma. The relatively short timescale between chevkinite-zircon crystallization and eruption suggests that crystal-poor rhyolites at La Primavera were erupted shortly after differentiation and/or reheating. These results indicate that 238U-230Th dating of chevkinite via ion microprobe analysis may be used to date crystallization and chemical evolution of silicic magmas.

  4. Evaluation of covariances for resolved resonance parameters of 235U, 238U, and 239Pu in JENDL-3.2

    International Nuclear Information System (INIS)

    Kawano, Toshihiko; Shibata, Keiichi

    2003-02-01

    Evaluation of covariances for resolved resonance parameters of 235 U, 238 U, and 239 Pu was carried out. Although a large number of resolved resonances are observed for major actinides, uncertainties in averaged cross sections are more important than those in resonance parameters in reactor calculations. We developed a simple method which derives a covariance matrix for the resolved resonance parameters from uncertainties in the averaged cross sections. The method was adopted to evaluate the covariance data for some important actinides, and the results were compiled in the JENDL-3.2 covariance file. (author)

  5. Fission-residues produced in the spallation reaction 238U + p at 1 A GeV

    International Nuclear Information System (INIS)

    Bernas, M.; Armbruster, P.; Benlliure, J.; Boudard, A.; Casarejos, E.; Czajkowski, S.; Enqvist, T.; Legrain, R.; Leray, S.; Mustapha, B.; Napolitani, P.; Pereira, J.; Rejmund, F.; Ricciardi, M.V.; Schmidt, K.H.; Stephan, C.; Taieb, J.; Tassan-Got, L.; Volant, C.

    2003-04-01

    Fission fragments from 1 A GeV 238 U projectiles irradiating a hydrogen target were investigated by using the fragment separator FRS for magnetic selection of reaction products including ray-tracing and ΔE-ToF techniques. The momentum spectra of identified fragments were analysed to provide isotopic production cross sections, fission-fragment velocities and recoil momenta of the fissioning parent nuclei. Besides their general relevance, these quantities are also demanded for applications. Calculations and simulations with codes commonly used and recently developed or improved are compared to the data. (orig.)

  6. Transfer of 210Po, 210Pb and 238U from some medicinal plants to their essential oils

    International Nuclear Information System (INIS)

    Al-Masri, M.S.; Amin, Y.; Ibrahim, S.; Nassri, M.

    2015-01-01

    Essential oils were extracted from 35 medicinal plants used by Syrians, organic compounds were determined in these oils and concentrations of 210 Po 210 Pb and 238 U were determined in the original plants and in the essential oils. The results showed that the highest activity concentrations of 210 Po and 210 Pb were found in leaves with large surfaces and in Sage were as high as 73.5 Bq kg −1 and 73.2 Bq kg −1 , respectively. The activity concentration of 238 U was as high as 4.26 Bq kg −1 in Aloe. On the other hand, activity concentrations of 210 Po ranged between 0.2 and 71.1 Bq kg −1 in extracted essential oils for Rosemary and False yellowhead, respectively. The activity concentration of 210 Pb reached 63.7 Bq kg −1 in Aloe oil. The activity concentrations of 238 U were very low in all extracted oils; the highest value was 0.31 Bq kg −1 in peel of Orange oil. The transfer of 210 Po and 210 Pb from plant to its oil was the highest for Eugenia; 7.1% and 5.5% for 210 Po and 210 Pb, respectively. A linear relationship was found between the transfer factor of radionuclides from plant to its essential oil and the chemical content of this oil. - Highlights: • Natural radionuclides 210 Po, 210 Pb and 238 U were determined in 35 medicinal plants and their essential oils. • The highest activity concentration of 210 Po and 210 Pb were 73.5 Bq kg −1 and 73.2 Bq kg −1 in Sage, respectively. • The transfer of 210 Po and 210 Pb from Eugenia plant to its oil was the highest amongst other plants. • The data obtained in this study can be considered the first reported data for medicinal plants and their oils in Syria

  7. Neutron and gamma-ray emission in the proton induced fission of {sup 238}U and {sup 242}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Kniajeva, G.N.; Krupa, L.; Bogachev, A.A.; Chubarian, G.G.; Dorvaux, O.; Itkis, I.M.; Itkis, M.G.; Kliman, J.; Khlebnikov, S.; Kondratiev, N.A.; Kozulin, E.M.; Lyapin, V.; Materna, T.; Pokrovsky, I.V.; Rubchenya, V.A.; Trzaska, W.H.; Vakhtin, D.; Voskressenski, V.M

    2004-04-05

    Average prescission M{sup pre}{sub n} and postscission M{sup post}{sub n} neutron multiplicities as well as average {gamma}-ray multiplicity , average energy emitted by {gamma}-rays as a function of mass and total kinetic energy (TKE) of fission fragments were measured in proton induced reactions p+{sup 242}Pu{yields}{sup 243}Am, p+{sup 238}U{yields}{sup 239}Np at proton energy E{sub p}=13, 20 and 55 MeV.

  8. Fission Product Yields for 14 MeV Neutrons on 235U, 238U and 239Pu

    International Nuclear Information System (INIS)

    Mac Innes, M.; Chadwick, M.B.; Kawano, T.

    2011-01-01

    We report cumulative fission product yields (FPY) measured at Los Alamos for 14 MeV neutrons on 235 U, 238 U and 239 Pu. The results are from historical measurements made in the 1950s–1970s, not previously available in the peer reviewed literature, although an early version of the data was reported in the Ford and Norris review. The results are compared with other measurements and with the ENDF/B-VI England and Rider evaluation. Compared to the Laurec (CEA) data and to ENDF/B-VI evaluation, good agreement is seen for 235 U and 238 U, but our FPYs are generally higher for 239 Pu. The reason for the higher plutonium FPYs compared to earlier Los Alamos assessments reported by Ford and Norris is that we update the measured values to use modern nuclear data, and in particular the 14 MeV 239 Pu fission cross section is now known to be 15–20% lower than the value assumed in the 1950s, and therefore our assessed number of fissions in the plutonium sample is correspondingly lower. Our results are in excellent agreement with absolute FPY measurements by Nethaway (1971), although Nethaway later renormalized his data down by 9% having hypothesized that he had a normalization error. The new ENDF/B-VII.1 14 MeV FPY evaluation is in good agreement with our data.

  9. Neutron induced fission cross sections for 232Th, 235,238U, 237Np, and 239Pu

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Ullmann, J.L.; Balestrini, S.J.; Hill, N.W.; Carlson, A.D.; Wasson, O.A.

    1989-01-01

    Neutron-induced fission cross section ratios for samples of 232 Th, 235,238 U, 237 Np and 239 Pu have been measured from 1 to 400 MeV. The fission reaction rate was determined for all samples simultaneously using a fast parallel plate ionization chamber at a 20-m flight path. A well characterized annular proton recoil telescope was used to measure the neutron fluence from 3 to 30 MeV. Those data provided the shape of the 235 U(n,f) cross section relative to the hydrogen scattering cross section. That shape was then normalized to the very accurately known value for 235 U(n,f) at 14.178 MeV. From 30 to 400 MeV cross section values were determined using the neutron fluence measured with a plastic scintillator. Cross section values of 232 Th, 235,238 U, 237 Np and 239 Pu were computed from the ratio data using the authors' values for 235 U(n,f). In addition to providing new results at high neutron energies, these data highlight several areas of deficiency in the evaluated nuclear data files and provide new information for the 235 U(n,f) standard

  10. Uranium concentrations and 234U/238U activity ratios in fault-associated groundwater as possible earthquake precursors

    International Nuclear Information System (INIS)

    Finkel, R.C.

    1981-01-01

    In order to assess the utility of uranium isotopes as fluid phase earthquake precursors, uranium concentrations and 234 U/ 238 U activity ratios have been monitored on a monthly or bimonthly basis in water from 24 wells and springs associated with Southern California fault zones. Uranium concentrations vary from 0.002 ppb at Indian Canyon Springs on the San Jacinto fault to 8.3 ppb at Lake Hughes well on the San Andreas fault in the Palmdale area. 234 U/ 238 U activity ratios vary from 0.88 at Agua Caliente Springs on the Elsinore fault to 5.4 at Niland Slab well on the San Andreas fault in the Imperial Valley. There was one large earthquake in the study area during 1979, the 15 October 1979 M = 6.6 Imperial Valley earthquake. Correlated with this event, uranium concentrations varied by a factor of more than 60 and activity ratios by a factor of 3 at the Niland Slab site, about 70 km from the epicenter. At the other sites monitored, uranium concentrations varied in time, but with no apparent pattern, while uranium activity ratios remained essentially constant throughout the monitoring period

  11. A dispersive optical model potential for nucleon induced reactions on 238U and 232Th nuclei with full coupling

    Directory of Open Access Journals (Sweden)

    Chiba Satoshi

    2013-03-01

    Full Text Available A dispersive coupled-channel optical model potential (DCCOMP that couples the ground-state rotational and low-lying vibrational bands of 238U and 232Th nuclei is studied. The derived DCCOMP couples almost all excited levels below 1 MeV of excitation energy of the corresponding even-even actinides. The ground state, octupole, beta, gamma, and non-axial bands are coupled. The first two isobar analogue states (IAS populated in the quasi-elastic (p,n reaction are also coupled in the proton induced calculation, making the potential approximately Lane consistent. The coupled-channel potential is based on a soft-rotor description of the target nucleus structure, where dynamic vibrations are considered as perturbations of the rigid rotor underlying structure. Matrix elements required to use the proposed structure model in Tamura coupled-channel scheme are derived. Calculated ratio R(U238/Th232 of the total cross-section difference to the averaged σT for 238U and 232Th nuclei is shown to be in excellent agreement with measured data.

  12. DEVELOPMENT OF ENRICHMENT VERIFICATION ASSAY BASED ON THE AGE AND 235U AND 238U ACTIVITIES OF THE SAMPLES

    International Nuclear Information System (INIS)

    AL-YAMAHI, H.; EL-MONGY, S.A.

    2008-01-01

    Development of the enrichment verification methods is the backbone of the nuclear materials safeguards skeleton. In this study, the 235U percentage of depleted , natural and very slightly enriched uranium samples were estimated based on the sample age and the measured activity of 235U and 238U. The HpGe and NaI spectrometry were used for samples assay. A developed equation was derived to correlate the sample age and 235U and 238U activities with the enrichment percentage (E%). The results of the calculated E% by the deduced equation and the target E% values were found to be similar and within 0.58 -1.75% bias in the case of HpGe measurements. The correlation between them was found to be very sharp. The activity was also calculated based on the measured sample count rate and the efficiency at the gamma energies of interest. The correlation between the E% and the 235U activity was estimated and found to be linearly sharp. The results obtained by NaI was found to be less accurate than these obtained by HpGe. The bias in the case of NaI assay was in the range from 6.398% to 22.8% for E% verification

  13. Environmental geochemistry of 238U, 232Th, 40K and some heavy metals in River Nile sediments

    International Nuclear Information System (INIS)

    Siddeeg, S. M. B.

    2007-06-01

    Environmental geochemistry is concerned with the abundance, distribution, and mobility of chemical elements in surface materials at the surface of earth crust. This study aimed at better understanding of geochemical behavior of 238 U, 23 '2Th and 40 K in river sediments and some heavy elements with emphasis on Mg, Ca, Mn, Fe, Ni, Cu, Zn and Pb. The analysis was conducted for a total of 33 bulk sediment samples from White Nile, Blue Nile and River Nile within Khartoum, the samples were fractionated into seven grain sizes each (2000-1000, 1000-500, 500-250, 250-200, 200-125, 125-100 and > 100 μm), using high resolution gamma spectrometer for radionuclides measurements, whereas Particle Induced X-ray Emission (PIXE) was used for heavy metals analysis. On the average, the activity concentration of 238 U, 232 Th and 40 K were 17.90±5.23, 16.38±5.34 and 379.82±107.76 Bq -1 Kg in White Nile, 19.56±5.04, 17.72±4.69, and 494.36±105.79 Bq -1 Kg in Blue Nile and 19.27±2.88, 17.48±2.78, 359.50±83.15 Bq -1 Kg in the River Nile sediments. Results revealed inverse relationship between activity concentration and grain size in White and Blue Nile, while the trend is not clear in the River Nile. In general, the variation of the measured values within single grain size was smaller in White Nile compare to Blue and River Nile sediments, and it was observed that the data are highly scattered in grain size (200-125μm). The ratio between 238 U/ 232 Th is grater than unity in the three rivers indicating that there is relative enrichment of 238 U in the surface sediments. The activity concentration of the fallout radionuclide 137 Cs is one order of magnitude lower in the White Nile sediments (0.89±0.96) Bq -1 Kg compared to values in the Blue Nile sediments (3.60±1.55) Bq -1 Kg. Comparison of the values obtained for natural radionuclides and the fallout radionuclide ( 137 Cs in the three sites with the global data reflect low and /or insignificant difference. For heavy metal

  14. An alternative route for the preparation of the medical isotope 99Mo from the 238U(γ, f) and 100Mo(γ, n) reactions

    International Nuclear Information System (INIS)

    Naik, H.; Goswami, A.; Suryanarayana, S.V.; Jagadeesan, K.C.; Thakare, S.V.; Joshi, P.V.; Nimje, V.T.; Mittal, K.C.; Venugopal, V.; Kailas, S.

    2013-01-01

    The radionuclide 99 Mo, which has a half-life of 65.94 h was produced from 238 U(γ, f) and 100 Mo(γ, n) reactions using a 10 MeV electron linac at EBC, Kharghar Navi-Mumbai, India. This has been investigated since the daughter product 99m Tc is very important from a medical point of view and can be produced in a generator from the parent 99 Mo. The activity of 99 Mo was analyzed by a γ-ray spectrometric technique using a HPGe detector. From the detected γ-rays activity of 140.5 and 739.8 keV, the amount of 99 Mo produced was determined. For comparison, the amount of 99 Mo from 238 U(γ, f) and 100 Mo(γ, n) reactions was also estimated using the experimental photon flux from 197 Au(γ, n) 196 Au reaction. The amount of 99 Mo from the detected γ-lines is in agreement with the estimated value for 238 U(γ, f) and 100 Mo(γ, n) reactions. The production of 99 Mo activity from 238 U(γ, f) and 100 Mo(γ, n) reactions is a relevant and novel approach, which provides alternative routes to 235,238 U(n, f) and 98 Mo(n, γ) reactions, circumventing the need for a reactor. The viability and practicality of the 99 Mo production from the 238 U(γ, f) and 100 Mo(γ, n) reactions alternative to 235,238 U(n, f) and 98 Mo(n, γ) reactions has been emphasize. An estimate has been also arrived based on the experimental data of present work to fulfill the requirement of DOE. (author)

  15. The presence of radioactive materials in soil, sand and sediment samples of Potenga sea beach area, Chittagong, Bangladesh: Geological characteristics and environmental implication

    Science.gov (United States)

    Yasmin, Sabina; Barua, Bijoy Sonker; Uddin Khandaker, Mayeen; Kamal, Masud; Abdur Rashid, Md.; Abdul Sani, S. F.; Ahmed, H.; Nikouravan, Bijan; Bradley, D. A.

    2018-03-01

    Accurate quantification of naturally occurring radioactive materials in soil provides information on geological characteristics, possibility of petroleum and mineral exploration, radiation hazards to the dwelling populace etc. Of practical significance, the earth surface media (soil, sand and sediment) collected from the densely populated coastal area of Chittagong city, Bangladesh were analysed using a high purity germanium γ-ray spectrometer with low background radiation environment. The mean activities of 226Ra (238U), 232Th and 40K in the studied materials show higher values than the respective world average of 33, 36 and 474 Bq/kg reported by the UNSCEAR (2000). The deduced mass concentrations of the primordial radionuclides 238U, 232Th and 40K in the investigated samples are corresponding to the granite rocks, crustal minerals and typical rocks respectively. The estimated mean value of 232Th/238U for soil (3.98) and sediment (3.94) are in-line with the continental crustal average concentration of 3.82 for typical rock range reported by the National Council on Radiation Protection and Measurements (NCRP). But the tonalites and more silicic rocks elevate the mean value of 232Th/238U for sand samples amounting to 4.69. This indicates a significant fractionation during weathering or associated with the metasomatic activity in the investigated area of sand collection.

  16. Assessment of natural radionuclides concentration from 238U and 232Th series in Virginia and Burley varieties of Nicotiana tabacum L

    International Nuclear Information System (INIS)

    Silva, Carolina Fernanda da

    2015-01-01

    Brazil is the largest exporter and second largest producer of tobacco worldwide, according to the crop production of 2013/2014. The tobacco plant (Nicotiana tabacum L.) is used to manufacture all derivatives and the chemical composition of the resulting tobacco products varies with the type of tobacco leaves, how they are grown, the region where they are cultivated, the characteristics of preparation (compression, filter and paper) and the temperature variations resulting from the incomplete combustion of tobacco. Tobacco products are extensively used throughout the world, and the most consumed are cigarettes, cigars and narghile. The damaging effects that these products cause to human health are discussed globally, and many surveys are performed with the aim of relating the use of these products with various illnesses. There is a lack of information about the radiological characterization of the tobacco plant both in international and Brazilian literature. The objective of this study was to determine the concentration of radionuclides 238 U, 234 U, 230 Th, 22 '6Ra, 210 Pb and 210 Po, members from the 238 U decay series, and the radionuclides 232 Th and 228 Ra members of the 232 Th decay series in the varieties Burley and Virginia, which are the most cultivated in Brazil. Plants from these varieties were cultivated in pots with organic substrate and fertilizer and also acquired from the producers and analyzed by alpha spectrometry for U and Th isotopes and 210 Po determination, and gross alpha and beta counting, 228 Ra, 226 Ra and 210 Pb determination. The whole plant, from both places, was analyzed; root, stem, leaves, as well as the organic substrate, the fertilizers, and the soil. The results for U and Th isotopes presented values below the detection limits of the methods to the leaves and stems of all plants analyzed, with measurable results only in roots, soil, and substrate. The radionuclides 226 Ra, 228 Ra, 210 Pb, and 210 Po, were determined in most

  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

    .5 mkg/l concentrations of uranium (components from the Medlyanka river and Kultuchnaya river, respectively. The U abundances reflect relatively reduced conditions in group 1 and more oxidized in group 2. The higher (234U/238U in the surface water with intermediate concentrations of uranium (0.009–0.500 mkg/l may indicate the admixture of a groundwater component (Fig. 3. Figure 4 shows relations between surface water and groundwater components in the Kultuk polygon in terms of U content. In Figure 5, the field of data points of U and Sr isotope ratios in groundwater from the Kultuk polygon is contoured by curved lines that meet with each other at compositions corresponding to the end members E (87Sr/86Sr=0.7205, 234U/238U=1.0 and NE (87Sr/86Sr=0.70534, 234U/238U=3.3. Uranium ratios of the former and the latter components show equilibrium and the most nonequilibrium compositions, respectively. The field is characteristic of water samples from the rocks of the southern suture zone of the Siberian craton. Shift of the data points of water from stations 26 and 1310 to the right of this data field (i.e. with relative increasing 87Sr/86Sr is due to lateral transition from the rocks of the suture zone to the Archean rocks of the Sharyzhalgai block (Fig. 6. The isotope systematics of uranium and strontium in the strongly nonequilibrium uranium segment is supplemented by the systematics of uranium in (234U/238U vs. 1/U diagram (Fig. 7. The U composition in water from station 40 reflects a combination of processes that take place at station 27 (i.e. in the central part of the deformation system and at station 38 (i.e. at its periphery. Approximately equal contents of uranium at the three above‐mentioned stations may reflect similar oxidization levels of the medium. In the Southern Baikal basin, the Irkutsk Seismic Station recorded an earthquake of class 11.2 on 08 January 2013 [Map…, 2013]. The earthquake epicentre was located near Listvyanka settlement (51.85° N, 105°16

  18. The distribution of {sup 236}U/{sup 238}U in the North Atlantic and adjacent oceans; Die Verteilung von {sup 236}U/{sup 238}U im Nordatlantik und den angrenzenden Ozeanen

    Energy Technology Data Exchange (ETDEWEB)

    Christl, Marcus; Casacuberta, Nuria; Lachner, Johannes; Maxeiner, Sascha; Vockenhuber, Christof; Synal, Hans-Arno [Labor fuer Ionenstrahlphysik, ETH Zuerich (Switzerland); Herrmann, Juergen [Bundesamt fuer Seeschifffahrt und Hydroghraphie, Hamburg (Germany); Castrillejo, Maxi; Masque, Pere [Universitat Autonoma de Barcelona (Spain); Rutgers van der Loeff, Michiel [Alfred-Wegener-Institut, Bremerhaven (Germany)

    2015-07-01

    The technical developments of recent years, such as the introduction of helium as a stripping gas, make compact AMS systems probably among the most sensitive analyzers available for ultra-trace analyzes of actinides in the environment. Such systems are particularly suitable for the trace analysis of {sup 236}U since conventional mass spectrometry does not provide the necessary suppression of the substrate caused by molecules or neighboring masses. Over the past few years, unique data sets of {sup 236}U/{sup 238}U have been produced at the AMS System Tandy of the ETH Zurich in the Atlantic and Arctic Ocean as well as in the Mediterranean and the North Sea. This lecture will provide a brief overview of the latest technical developments in the field of heavy ion analysis at compact AMS plants at ETH Zurich. In the second part, the produced data sets are then assembled and the current understanding of this new ocean tracer discussed. [German] Die technischen Entwicklungen der letzten Jahre, wie zum Beispiel die Einfuehrung von Helium als stripper Gas, machen kompakte AMS Systeme wahrscheinlich zu den sensitivsten verfuegbaren Analysegeraeten fuer Ultra-Spurenstoffanalysen von Aktiniden in der Umwelt. Solche Systeme eignen sich im Besonderen zur Spurenanalyse von {sup 236}U, da konventionelle Massenspektrometrie hier nicht die erforderliche Unterdrueckung des durch Molekuele oder Nachbarmassen verursachten Untergrundes bietet. Am AMS System Tandy der ETH Zuerich wurden waehrend der letzten Jahre einzigartige Datensaetze von {sup 236}U/{sup 238}U im Atlantischen und Arktischen Ozean, sowie im Mittelmeer und der Nordsee produziert. In diesem Vortrag soll zunaechst ein kurzer Ueberblick ueber die neuesten technischen Entwicklungen im Bezug auf Schwerionen Analysen an kompakten AMS Anlagen der ETH Zuerich gegeben werden. Im zweiten Teil werden dann die produzierten Datensaetze zusammengefuegt und das gegenwaertige Verstaendnis dieses neuen Ozean-Tracers diskutiert.

  19. Neutron capture cross section measurement of 238U at the n TOF CERN facility with C6D6 scintillation detectors in the energy region from 1 eV to 700 keV

    CERN Document Server

    Mingrone, F.

    2017-01-01

    The aim of this work is to provide a precise and accurate measurement of the 238U(n,g) reaction cross section in the energy region from 1 eV to 700 keV. This reaction is of fundamental importance for the design calculations of nuclear reactors, governing the behaviour of the reactor core. In particular, fast reactors, which are experiencing a growing interest for their ability to burn radioactive waste, operate in the high energy region of the neutron spectrum. In this energy region most recent evaluations disagree due to inconsistencies in the existing measurements of up to 15%. In addition, the assessment of nuclear data uncertainty performed for innovative reactor systems shows that the uncertainty in the radiative capture cross-section of 238U should be further reduced to 1-3% in the energy region from 20 eV to 25 keV. To this purpose, addressed by the Nuclear Energy Agency as a priority nuclear data need, complementary experiments, one at the GELINA and two at the n_TOF facility, were proposed and carrie...

  20. Neutron capture cross section measurement of $^{238}$U at the n_TOF CERN facility in the energy region from 1 eV to 700 keV

    CERN Document Server

    Mingrone, F; Vannini, G; Colonna, N; Gunsing, F; Zugec, P; Altstadt, S; Andrzejewski, J; Audouin, L; Barbagallo, M; Becares, V; Becvavr, F; Belloni, F; Berthoumieux, E; Billowes, J; Bosnar, D; Brugger, M; Calviani, M; Calvino, F; Cano-Ott, D; Carrapico, C; Cerutti, F; Chiaveri, E; Chin, M; Cortes, G; Cortes-Giraldo, M A; Diakaki, M; Domingo-Pardo, C; Duran, I; Dressler, R; Eleftheriadis, C; Ferrari, A; Fraval, K; Ganesan, S; Garcia, A R; Giubrone, G; Goncalves, I F; Gonzalez-Romero, E; Griesmayer, E; Guerrero, C; Hernandez-Prieto, A; Jenkins, D G; Jericha, E; Kadi, Y; Kappeler, F; Karadimos, D; Kivel, N; Koehler, P; Kokkoris, M; Krticka, M; Kroll, J; Lampoudis, C; Langer, C; Leal-Cidoncha, E; Lederer, C; Leeb, H; Leong, L S; Lo Meo, S; Losito, R; Mallick, A; Manousos, A; Marganiec, J; Martinez, T; Mastinu, P F; Mastromarco, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mirea Horia, 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; Sabate-Gilarte, M; Sarmento, R; Saxena, A; Schillebeeckx, P; Schmidt, S; Schumann, D; Tagliente, G; LTain, J; Tarrio, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Variale, V; Vaz, P; Ventura, A; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiss, C; Wright, T

    2016-01-01

    The aim of this work is to provide a precise and accurate measurement of the $^{238}$U(n,$\\gamma$) reaction cross section in the energy region from 1 eV to 700 keV. This reaction is of fundamental importance for the design calculations of nuclear reactors, governing the behaviour of the reactor core. In particular, fast reactors, which are experiencing a growing interest for their ability to burn radioactive waste, operate in the high energy region of the neutron spectrum. In this energy region most recent evaluations disagree due to inconsistencies in the existing measurements of up to 15%. In addition, the assessment of nuclear data uncertainty performed for innovative reactor systems shows that the uncertainty in the radiative capture cross-section of $^{238}$U should be further reduced to 1-3% in the energy region from 20 eV to 25 keV. To this purpose, addressed by the Nuclear Energy Agency as a priority nuclear data need, complementary experiments, one at the GELINA and two at the n_TOF facility, were pr...

  1. ENDF/B-IV representation of the 238U total neutron cross section in the resolved resonance energy region

    International Nuclear Information System (INIS)

    de Saussure, G.; Olsen, D.K.; Perez, R.B.

    1976-01-01

    The ENDF/B-IV prescription fails to represent correctly the 238 U total (and scattering) cross section between the levels of the resolved range. It is shown how this representation can be improved by properly accounting for the contribution of levels outside the resolved region to the cross section at energies inside the resolved region, and by substituting the more precise multilevel Breit-Wigner formula for the presently used single-level formula. The importance of computing accurately the minima in the total cross section is illustrated by comparing values of the self-shielded capture resonance integral computed with ENDF/B-IV and with a more accurate cross section model

  2. New approximations for the interference term applied to the calculation of scattering cross section of the {sup 238} U isotope

    Energy Technology Data Exchange (ETDEWEB)

    Palma, Daniel Artur Pinheiro [Centro Federal de Educacao Tecnologica de Quimica de Nilopolis, RJ (Brazil)]. E-mails: dpalma@cefeteq.br; Martinez, Aquilino Senra; Goncalves, Alessandro C. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE). Programa de Engenharia Nuclear]. E-mail: agoncalves@con.ufrj.br; aquilino@lmp.ufrj.br

    2008-07-01

    The calculation of the Doppler broadening function and the interference term are very important in the generation of nuclear data. Recent papers have proposed analytical formulations for both functions and, despite their being simple and precise, they contain the error function with a complex argument. With the intention of simplifying the mathematical treatment two approximations are proposed in this paper. The first one consists of using an expansion in the form of series to treat the error function. The other approximation is based on simplifications in the differential equations that govern the Doppler broadening function. For validation purpose the result obtained is compared to the one obtained in the calculation of the cross sections for isotope {sup 238}U for different resonances. Results obtained have proved satisfactory from the standpoint of accuracy. (author)

  3. New approximations for the interference term applied to the calculation of scattering cross section of the 238 U isotope

    International Nuclear Information System (INIS)

    Palma, Daniel Artur Pinheiro; Martinez, Aquilino Senra; Goncalves, Alessandro C.

    2008-01-01

    The calculation of the Doppler broadening function and the interference term are very important in the generation of nuclear data. Recent papers have proposed analytical formulations for both functions and, despite their being simple and precise, they contain the error function with a complex argument. With the intention of simplifying the mathematical treatment two approximations are proposed in this paper. The first one consists of using an expansion in the form of series to treat the error function. The other approximation is based on simplifications in the differential equations that govern the Doppler broadening function. For validation purpose the result obtained is compared to the one obtained in the calculation of the cross sections for isotope 238 U for different resonances. Results obtained have proved satisfactory from the standpoint of accuracy. (author)

  4. Study of 236U/238U ratio at CIRCE using a 16-strip silicon detector with a TOF system

    Science.gov (United States)

    De Cesare, M.; De Cesare, N.; D'Onofrio, A.; Gialanella, L.; Terrasi, F.

    2015-04-01

    Accelerator Mass Spectrometry (AMS) is presently the most sensitive technique for the measurement of long-lived actinides, e.g. 236U and xPu isotopes. A new actinide AMS system, based on a 3-MV pelletron tandem accelerator, is operated at the Center for Isotopic Research on Cultural and Environmental Heritage (CIRCE) in Caserta, Italy. In this paper we report on the procedure adopted to increase the 236U abundance sensitivity as low as possible. The energy and position determinations of the 236U ions, using a 16-strip silicon detector have been obtained. A 236U/238U isotopic ratio background level of about 2.9×10-11 was obtained, summing over all the strips, using a Time of Flight-Energy (TOF-E) system with a 16-strip silicon detector (4.9×10-12 just with one strip).

  5. Study of 236U/238U ratio at CIRCE using a 16-strip silicon detector with a TOF system

    Directory of Open Access Journals (Sweden)

    De Cesare M.

    2015-01-01

    Full Text Available Accelerator Mass Spectrometry (AMS is presently the most sensitive technique for the measurement of long-lived actinides, e.g. 236U and xPu isotopes. A new actinide AMS system, based on a 3-MV pelletron tandem accelerator, is operated at the Center for Isotopic Research on Cultural and Environmental Heritage (CIRCE in Caserta, Italy. In this paper we report on the procedure adopted to increase the 236U abundance sensitivity as low as possible. The energy and position determinations of the 236U ions, using a 16-strip silicon detector have been obtained. A 236U/238U isotopic ratio background level of about 2.9×10−11 was obtained, summing over all the strips, using a Time of Flight-Energy (TOF-E system with a 16-strip silicon detector (4.9×10−12 just with one strip.

  6. Fission product yields from 6 to 9 MeV neutron induced fission of 235U and 238U

    International Nuclear Information System (INIS)

    Chapman, T.C.

    1978-01-01

    The yields of 28 mass chains have been measured for fission of 235 U and 238 U induced by neutrons at four different energies from 6.0 to 9.1 MeV. This is the first experimental measurement where sufficient energy resolution was obtained to observe the effect of the onset of second-chance fission in the case of symmetric fission. The 111 Ag results are compared with measurements at other neutron energies and with previous theoretical predictions. Several of the nuclide results are presented in graphical form, and all nuclide results are presented in tabular form, as a function of neutron energy. The mass chains measured range from 84 to 156, and their half-lives range from 18 minutes to 30 years

  7. Fission Product Yield Study of 235U, 238U and 239Pu Using Dual-Fission Ionization Chambers

    Science.gov (United States)

    Bhatia, C.; Fallin, B.; Howell, C.; Tornow, W.; Gooden, M.; Kelley, J.; Arnold, C.; Bond, E.; Bredeweg, T.; Fowler, M.; Moody, W.; Rundberg, R.; Rusev, G.; Vieira, D.; Wilhelmy, J.; Becker, J.; Macri, R.; Ryan, C.; Sheets, S.; Stoyer, M.; Tonchev, A.

    2014-05-01

    To resolve long-standing differences between LANL and LLNL regarding the correct fission basis for analysis of nuclear test data [M.B. Chadwick et al., Nucl. Data Sheets 111, 2891 (2010); H. Selby et al., Nucl. Data Sheets 111, 2891 (2010)], a collaboration between TUNL/LANL/LLNL has been established to perform high-precision measurements of neutron induced fission product yields. The main goal is to make a definitive statement about the energy dependence of the fission yields to an accuracy better than 2-3% between 1 and 15 MeV, where experimental data are very scarce. At TUNL, we have completed the design, fabrication and testing of three dual-fission chambers dedicated to 235U, 238U, and 239Pu. The dual-fission chambers were used to make measurements of the fission product activity relative to the total fission rate, as well as for high-precision absolute fission yield measurements. The activation method was employed, utilizing the mono-energetic neutron beams available at TUNL. Neutrons of 4.6, 9.0, and 14.5 MeV were produced via the 2H(d,n)3He reaction, and for neutrons at 14.8 MeV, the 3H(d,n)4He reaction was used. After activation, the induced γ-ray activity of the fission products was measured for two months using high-resolution HPGe detectors in a low-background environment. Results for the yield of seven fission fragments of 235U, 238U, and 239Pu and a comparison to available data at other energies are reported. For the first time results are available for neutron energies between 2 and 14 MeV.

  8. Reactive transport of uranium in a groundwater bioreduction study: Insights from high-temporal resolution 238U/235U data

    Science.gov (United States)

    Shiel, A. E.; Johnson, T. M.; Lundstrom, C. C.; Laubach, P. G.; Long, P. E.; Williams, K. H.

    2016-08-01

    We conducted a detailed investigation of U isotopes in conjunction with a broad geochemical investigation during field-scale biostimulation and desorption experiments. This investigation was carried out in the uranium-contaminated alluvial aquifer of the Rifle field research site. In this well-characterized setting, a more comprehensive understanding of U isotope geochemistry is possible. Our results indicate that U isotope fractionation is consistently observed across multiple experiments at the Rifle site. Microbially-mediated reduction is suggested to account for most or all of the observed fractionation as abiotic reduction has been demonstrated to impart much smaller, often near-zero, isotopic fractionation or isotopic fractionation in the opposite direction. Data from some time intervals are consistent with a simple model for transport and U(VI) reduction, where the fractionation factor (ε = +0.65‰ to +0.85‰) is consistent with experimental studies. However, during other time intervals the observed patterns in our data indicate the importance of other processes in governing U concentrations and 238U/235U ratios. For instance, we demonstrate that departures from Rayleigh behavior in groundwater systems arise from the presence of adsorbed species. We also show that isotope data are sensitive to the onset of oxidation after biostimulation ends, even in the case where reduction continues to remove contaminant uranium downstream. Our study and the described conceptual model support the use of 238U/235U ratios as a tool for evaluating the efficacy of biostimulation and potentially other remedial strategies employed at Rifle and other uranium-contaminated sites.

  9. Implementation of new integrated evaporation equipment for the preparation of 238U targets and improvement of the deposition process

    Science.gov (United States)

    Vanleeuw, D.; Lewis, D.; Moens, A.; Sibbens, G.; Wiss, T.

    2018-05-01

    Measurement of neutron cross section data is a core activity of the JRC-Directorate G for Nuclear Safety and Security in Geel. After a period of reduced activity and in line with a renewed interest for nuclear data required for GenIV reactors and waste minimization, the demand for high quality actinide targets increased. Physical vapour deposition by thermal evaporation is a key technique to prepare homogeneous thin actinide layers, but due to ageing effects the earlier in-house developed equipment can no longer provide the required quality. Because of a current lack of experience and human resources cooperation with private companies is required for the development of new deposition equipment directly integrated in a glove box. In this paper we describe the design, implementation and validation of the first commercial actinide evaporator in a glove box as well as the optimization of the deposition process. Highly enriched 238U3O8 was converted to 238UF4 powder and several deposition runs were performed on different substrates. The deposition parameters were varied and defined in order to guarantee physical and chemical stable homogeneous UF4 layers, even on polished substrates which was not longer feasible with the older equipment. The stability problem is discussed in view of the thin layer growth by physical vapour deposition and the influence of the deposition parameters on the layer quality. The deposits were characterized for the total mass by means of substitution weighing and for the areal density of 238U by means of alpha particle counting and thermal ionization mass spectrometry (TIMS). The quality of the layer was visually evaluated and by means of stereo microscopy and auto radiography.

  10. Measurement of the 238U subthreshold fission cross section for incident neutron energies between 0.6 and 100 keV

    International Nuclear Information System (INIS)

    Difilippo, F.C.; Perez, R.B.; de Saussure, G.; Olsen, D.K.; Ingle, R.W.

    1977-01-01

    The neutron-induced 238 U subthreshold fission cross section has been measured in the neutron energy range between 0.6 and 100 keV. A total of 28 fission clusters were identified. The well-known clusters at 721 and 1210 eV appeared resolved into their Class I components. Average 238 U subthreshold fission cross sections were determined and compared with available results in the literature. The measurement is interpreted in terms of fission doorway (Class II levels) arising from the assumption of the existence of a double-humped fission barrier for the ( 238 U + n) compound nucleus at large deformations. On the basis of this model, several fission barrier parameters were determined

  11. Extreme fractionation of 234U 238U and 230Th 234U in spring waters, sediments, and fossils at the Pomme de Terre Valley, southwestern Missouri

    Science.gov (United States)

    Szabo, B. J.

    1982-01-01

    Isotopic fractionation as great as 1600% exists between 234U and 238U in spring waters, sediments, and fossils in the Pomme de Terre Valley, southwestern Missouri. The activity ratios of 234U 238U in five springs range from 7.2 to 16 in water which has been discharged for at least the past 30,000 years. The anomalies in 234U 238U ratio in deep water have potential usefulness in hydrologic investigations in southern Missouri. Clayey units overlying the spring bog sediments of Trolinger Spring are enriched in 230Th relative to their parent 234U by as much as 720%. The results indicate that both preferential displacement via alpha recoil ejection and the preferential emplacement via recoiling and physical entrapment are significant processes that are occurring in the geologic environment. ?? 1982.

  12. Resonance parameters of the 6.67-, 20.9-, and 36.8-eV levels in 238U

    International Nuclear Information System (INIS)

    Olsen, D.K.; de Saussure, G.; Perez, R.B.; Difilippo, F.C.

    1976-01-01

    The ENDF/B-IV 238 U cross sections (MAT-1262) yield an effective capture resonance integral in strongly self-shielded situations which is too high. This situation suggests that the ENDF/B capture widths for the first few s-wave levels may be too large. Recent ORELA measurements of transmission through 238 U have been analyzed with a multilevel formula to determine the parameters of the 6.67-, 20.9-, and 36.6-eV levels. These three levels provide 86 percent of the infinitely dilute capture resonance integral

  13. Fission cross sections of {sup 235,238}U and {sup 209}Bi at incident proton energies above 70 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Obukhov, A I; Rimskij-Korsakov, A A; Eismont, V P [V.G. Khlopin Radium Inst., St. Petersburg (Russian Federation)

    1997-06-01

    The proton fission cross-section data of {sup 235,238}U and Bi were measured in the V.G. Khlopin Radium Institute over a wide proton energy range. The experimental and calculated data were also compared with experimental neutron values. The proton cross-section of {sup 235,238}U increased up to 60-70 MeV and then decreased. The bismuth proton fission cross-section increased in line with the rise in proton energy up to 1 GeV. (author). 21 refs, 6 figs.

  14. Reaction and fission cross-sections of 750AMeV 238U ions on Pb, Cu and AI-targets

    International Nuclear Information System (INIS)

    Hesse, M.; Aumann, T.; Czajkowski, S.; Dessagne, P.; Hanelt, E.; Kozhuharov, C.; Miehe, C.; Pfuetzner, M.; Roehl, C.; Schwab, W.; Stephan, C.; Tassan-Got, L.

    1995-09-01

    Charge-loss and fission cross-sections of 238 U at 750 A.MeV were measured on Al, Cu and Pb targets. The charge-loss rate was obtained by the attenuation method. Fission was selected by detecting the pair of highly ionizing fragments. Since the neutron-loss cross sections were measured in a parallel experiment for the same projectiles, all cross sections contributing to 238 U collisions on nuclei are available now as function of the target mass number and can be compared with current models. (orig.)

  15. Measurement of 238U and 232Th radionuclides in ilmenite and synthetic rutile

    Science.gov (United States)

    Idris, M. I.; Siong, K. K.; Fadzil, S. M.

    2018-01-01

    The only factory that currently processes ilmenite to produce synthetic rutile is Tor Minerals in Ipoh, Perak, Malaysia. These two minerals contain radioactive elements such as uranium and thorium. Furthermore, this factory was built close to the residential areas. Thus, the primary issues are radiation exposure attributed to the decay of the radionuclides. Hence, the objectives of this study are to measure the dose and to evaluate activity levels of uranium and thorium. Dose rates from surrounding area of factory indicate the normal range for both on the surface and 1 meter above the ground (0.3-0.7 μSv/hr) lower than the global range of 0.5-1.3 μSv/hr set by UNSCEAR. The mean activity levels of uranium and thorium for ilmenite are 235 Bq/kg and 503 Bq/kg while for synthetic rutile are 980 Bq/kg and 401 Bq/kg, respectively. The result shows that uranium activity levels of synthetic rutile is 4 times higher than ilmenite but it is still lower than the regulatory exemption limit of 1000 Bq/kg set by IAEA Basic Safety Standards. Even though the dose rates at the factory and the activity levels are within safe limits, safety precautions must be followed by the factory management to prevent any unwanted accident to occur.

  16. 238U And 232Th Concentration In Rock Samples using Alpha Autoradiography and Gamma Spectroscopy Techniques

    International Nuclear Information System (INIS)

    Hafez, A.F.; El-Farrash, A.H.; Yousef, H.A.

    2009-01-01

    The activity concentrations of uranium and thorium were measured for some rock samples selected from Dahab region in the south tip of Sinai. In order to detect any harmful radiation that would affect on the tourists and is becoming economic resource because Dahab have open fields of tourism in Egypt. The activity concentration of uranium and thorium in rocks samples was measured using two techniques. The first is .-autoradiography technique with LR-115 and CR-39 detectors and the second is gamma spectroscopic technique with NaI(Tl) detector. It was found that the average activity concentrations of uranium and thorium using .-autoradiography technique ranged from 6.41-49.31 Bqkg-1, 4.86- 40.87 Bqkg-1 respectively and by gamma detector are ranged from 6.70- 49.50 Bqkg-1, 4.47- 42.33 Bqkg-1 respectively. From the obtained data we can conclude that there is no radioactive healthy hazard for human and living beings in the area under investigation. It was found that there are no big differences between the calculated thorium to uranium ratios in both techniques

  17. 232-Th and 238-U radioactive contaminations of sediments along the South China Sea of East Coast Peninsular Malaysia by INAA

    International Nuclear Information System (INIS)

    Khadijeh Rezaee Ebrahim Saraee; Elias Saion; Naghavi, K.

    2009-01-01

    The concentrations of 232 Th and 238 U were determined in 30 sediment samples, collected from the South China Sea bed of the east coast peninsular Malaysia. The samples were dried in an oven for 10 days at 65 C and stored in polyethylene bottles for future analysis. INAA used to analyse surficial sediments. The 232 Th and 238 U activities in surficial sediments determined. These activities increased from 14.02 to 30.17 Bq Kg -1 and from 47.49 to 113.69 Bq Kg -1 for 232 Th and 238 U , respectively. Results show diffuse distribution of 232 Th and 238 U actinides in studied area. The Th/Sc and U/Sc ratios of the suricial sediments have same distribution and the highest their values are in station EC12. The radioactive contamination of the investigated sector is compared with the results obtained of other coastal sediments of Malaysia. Results show activity contamination in coastal sediments of the South China Sea is lower than the Straits of Malacca and is the same with the Straits of Johor. (Author)

  18. Transfer of {sup 40}K, {sup 238}U, {sup 210}Pb, and {sup 210}Po from soil to plant in various locations in south of Syria

    Energy Technology Data Exchange (ETDEWEB)

    Al-Masri, M.S. [Atomic Energy Commission of Syria, Damascus, P.O. Box 6091 (Syrian Arab Republic)], E-mail: scientific1@aec.org.sy; Al-Akel, B.; Nashawani, A.; Amin, Y.; Khalifa, K.H.; Al-Ain, F. [Atomic Energy Commission of Syria, Damascus, P.O. Box 6091 (Syrian Arab Republic)

    2008-02-15

    Transfer factors of {sup 40}K, {sup 238}U, {sup 210}Pb, and {sup 210}Po from soil to some agriculture crops in various locations in south of Syria (Dara'a and Assuwaydaa districts) have been determined. Soil and vegetable crops (green pepper, cucumber, tomato, and eggplant), legumes crops (lentil, chickpea, and broad bean), fruit trees (apple, grape, and olives) and cereals (barley and wheat) were collected and analyzed for {sup 238}U, {sup 210}Pb, and {sup 210}Po. The results have shown that higher transfer factors (calculated as Bq kg{sup -1} dry wt. plant material per Bq kg{sup -1} dry wt. soil) for {sup 210}Po, {sup 210}Pb and {sup 238}U were observed in vegetable leaves than fruits and cereals leaves; the highest values of transfer factor (TF) for {sup 238}U were found to be 0.1 for straw of chickpea. Transfer factors for {sup 210}Po varied between 2.8 x 10{sup -2} and 2 in fruits of eggplant and grain of barley, respectively. In addition, several parameters affecting transfer factors of the radionuclides were evaluated. The results can be considered as base values for TF of natural radionuclides in the region.

  19. Measurement of Fragment Mass Distributions in Neutron-induced Fission of {sup 238}U and {sup 232}Th at Intermediate Energies

    Energy Technology Data Exchange (ETDEWEB)

    Simutkin, V.D. [Uppsala University, P.O Box 525, SE-751 20 Uppsala (Sweden)

    2008-07-01

    Conceptual analysis of accelerator-driven systems assumes extensive use of nuclear data on neutron-induced reactions at intermediate energies. In particular, information about the fission fragment yields from the {sup 238}U(n,f) and {sup 232}Th(n,f) reactions is of particular interest at neutron energies from 10 to 200 MeV. However, there is a lack of such data for both {sup 238}U and {sup 232}Th. Up to now, the intermediate energy measurements have been performed for {sup 238}U only, and there are no data for the {sup 232}Th(n,f) reaction. The aim of the work is to provide such data. Fission fragment mass distributions for the {sup 232}Th(n,f) and {sup 238}U(n,f) reactions have been measured for the incident neutron energies 32.8 MeV, 45.3 MeV and 59.9 MeV. The experiments have been performed at the neutron beam facility of the Universite Catholique de Louvain, Belgium. A multi-section Frisch-gridded ionization chamber has been used as a fission fragment detector. The data obtained have been interpreted in terms of the multimodal random neck-rupture model (MMRNRM). (authors)

  20. Evaluation of the excitation function of the 238U(n,2n)237U reaction for neutron energies from threshold to 19 MeV

    International Nuclear Information System (INIS)

    Kornilov, N.V.; Vinogradov, V.N.; Gay, E.V.; Rabotnov, N.S.; Salnikov, O.A.; Raics, P.; Daroczy, S.; Nagy, S.; Csikai, J.

    1983-01-01

    Experimental results for the 238 U(n,2n) reaction were collected from the literature and evaluated. The normalisation of the measured cross sections was carried out using recent values for the cross sections of standard monitor reactions as well as new nuclear decay data. The evaluated excitation function was then obtained by the Pade-approximation. (Auth.)

  1. Transfer of 40K, 238U, 210Pb, and 210Po from soil to plant in various locations in south of Syria

    International Nuclear Information System (INIS)

    Al-Masri, M.S.; Al-Akel, B.; Nashawani, A.; Amin, Y.; Khalifa, K.H.; Al-Ain, F.

    2008-01-01

    Transfer factors of 40 K, 238 U, 210 Pb, and 210 Po from soil to some agriculture crops in various locations in south of Syria (Dara'a and Assuwaydaa districts) have been determined. Soil and vegetable crops (green pepper, cucumber, tomato, and eggplant), legumes crops (lentil, chickpea, and broad bean), fruit trees (apple, grape, and olives) and cereals (barley and wheat) were collected and analyzed for 238 U, 210 Pb, and 210 Po. The results have shown that higher transfer factors (calculated as Bq kg -1 dry wt. plant material per Bq kg -1 dry wt. soil) for 210 Po, 210 Pb and 238 U were observed in vegetable leaves than fruits and cereals leaves; the highest values of transfer factor (TF) for 238 U were found to be 0.1 for straw of chickpea. Transfer factors for 210 Po varied between 2.8 x 10 -2 and 2 in fruits of eggplant and grain of barley, respectively. In addition, several parameters affecting transfer factors of the radionuclides were evaluated. The results can be considered as base values for TF of natural radionuclides in the region

  2. Investigating Uranium Mobility Using Stable Isotope Partitioning of 238U/235U and a Reactive Transport Model

    Science.gov (United States)

    Bizjack, M.; Johnson, T. M.; Druhan, J. L.; Shiel, A. E.

    2015-12-01

    We report a numerical reactive transport model which explicitly incorporates the effectively stable isotopes of uranium (U) and the factors that influence their partitioning in bioactive systems. The model reproduces trends observed in U isotope ratios and concentration measurements from a field experiment, thereby improving interpretations of U isotope ratios as a tracer for U reactive transport. A major factor contributing to U storage and transport is its redox state, which is commonly influenced by the availability of organic carbon to support metal-reducing microbial communities. Both laboratory and field experiments have demonstrated that biogenic reduction of U(VI) fractionates the stable isotope ratio 238U/235U, producing an isotopically heavy solid U(IV) product. It has also been shown that other common reactive transport processes involving U do not fractionate isotopes to a consistently measurable level, which suggests the capacity to quantify the extent of bioreduction occurring in groundwater containing U using 238U/235U ratios. A recent study of a U bioremediation experiment at the Rifle IFRC site (Colorado, USA) applied Rayleigh distillation models to quantify U stable isotope fractionation observed during acetate amendment. The application of these simplified models were fit to the observations only by invoking a "memory-effect," or a constant source of low-concentration, unfractionated U(VI). In order to more accurately interpret the measured U isotope ratios, we present a multi-component reactive transport model using the CrunchTope software. This approach is capable of quantifying the cycling and partitioning of individual U isotopes through a realistic network of transport and reaction pathways including reduction, oxidation, and microbial growth. The model incorporates physical heterogeneity of the aquifer sediments through zones of decreased permeability, which replicate the observed bromide tracer, major ion chemistry, U concentration, and U

  3. Assessment of natural radionuclides concentration from {sup 238}U and {sup 232}Th series in Virginia and Burley varieties of Nicotiana tabacum L; Avaliacao da concentracao dos radionuclideos naturais das series do {sup 238}U e {sup 232}Th nas variedades Burley e Virginia da Nicotiana tabacum L.

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Carolina Fernanda da

    2015-07-01

    Brazil is the largest exporter and second largest producer of tobacco worldwide, according to the crop production of 2013/2014. The tobacco plant (Nicotiana tabacum L.) is used to manufacture all derivatives and the chemical composition of the resulting tobacco products varies with the type of tobacco leaves, how they are grown, the region where they are cultivated, the characteristics of preparation (compression, filter and paper) and the temperature variations resulting from the incomplete combustion of tobacco. Tobacco products are extensively used throughout the world, and the most consumed are cigarettes, cigars and narghile. The damaging effects that these products cause to human health are discussed globally, and many surveys are performed with the aim of relating the use of these products with various illnesses. There is a lack of information about the radiological characterization of the tobacco plant both in international and Brazilian literature. The objective of this study was to determine the concentration of radionuclides {sup 238}U, {sup 234}U, {sup 230}Th, {sup 22}'6Ra, {sup 210}Pb and {sup 210}Po, members from the {sup 238}U decay series, and the radionuclides {sup 232}Th and {sup 228}Ra members of the {sup 232}Th decay series in the varieties Burley and Virginia, which are the most cultivated in Brazil. Plants from these varieties were cultivated in pots with organic substrate and fertilizer and also acquired from the producers and analyzed by alpha spectrometry for U and Th isotopes and {sup 210}Po determination, and gross alpha and beta counting, {sup 228}Ra, {sup 226}Ra and {sup 210}Pb determination. The whole plant, from both places, was analyzed; root, stem, leaves, as well as the organic substrate, the fertilizers, and the soil. The results for U and Th isotopes presented values below the detection limits of the methods to the leaves and stems of all plants analyzed, with measurable results only in roots, soil, and substrate. The

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

    International Nuclear Information System (INIS)

    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 5000 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. 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.

  6. Intake of 238U and 232Th through the consumption of foodstuffs by tribal populations practicing slash and burn agriculture in an extremely high rainfall area

    International Nuclear Information System (INIS)

    Jha, S.K.; Gothankar, S.; Iongwai, P.S.; Kharbuli, B.; War, S.A.; Puranik, V.D.

    2012-01-01

    The concentration of naturally occurring radionuclides 232 Th, 238 U was determined using Instrumental Neutron Activation Analysis (INAA) in different food groups namely cereals, vegetables, leafy vegetables, roots and tubers cultivated and consumed by tribal population residing around the proposed uranium mine. The study area is a part of rural area K. P. Mawthabah (Domiasiat) in the west Khasi Hills District of Meghalaya, India located in the tropical region of high rainfall that remains steeped in tribal tradition without much outside influence. Agriculture by Jhum (slash and burn) cultivation and animal husbandry are the main occupation of the tribal populations. A total of 89 samples from locally grown food products were analyzed. The concentration of 238 U and 232 Th in the soil of the study area was found to vary 1.6–15.5 and 2.0–5.0 times respectively to the average mean value observed in India. The estimated daily dietary intake of 238 U and 232 Th were 2.0 μg d −1 (25 mBq d −1 ) and 3.4 μg d −1 (14 mBq d −1 ) is comparable with reported range 0.5–5.0 μg d −1 and 0.15–3.5 μg d −1 respectively for the Asian population. - Highlights: ► 232 Th, 238 U were determined using Instrumental Neutron Activation Analysis (INAA). ► Study area located in the tropical region of high rainfall that remains steeped in tribal tradition. ► Agriculture by Jhum (slash and burn) cultivation and animal husbandry are the main occupation of the tribal populations. ► The estimated daily intake of 232 Th and 238 U in high rainfall area was found to be 3.4 and 2.0 μg respectively.

  7. 238U-234U-230Th chronometry of Fe-Mn crusts: Growth processes and recovery of thorium isotopic ratios of seawater

    International Nuclear Information System (INIS)

    Chabaux, F.; Cohen, A.S.; O'Nions, R.K.; Hein, J.R.

    1995-01-01

    Comparison of ( 234 U) excess /( 238 U) and ( 230 Th)/( 232 Th) activity ratios in oceanic Fe-Mn deposits provides a method for assessing the closed-system behaviour of 238 U- 234 U- 230 Th, as well as variations in the initial uranium and thorium isotopic ratios of the precipitated metal oxides. This approach is illustrated using a Fe-Mn crust from Lotab seamount (Marshall Islands, west equatorial Pacific). Here we report uranium and thorium isotopic compositions in five subsamples from the surface of one large 5 cm diameter botyroid of this crust, and from two depth profiles of the outermost rim of the same botyroid. The decrease of ( 234 U) excess /( 238 U) and ( 230 Th/ 232 Th) activity ratio with depth in the two profiles gives mean growth rates, for the last 150 ka, of 7.8 ± 2 mm/Ma and 6.6 ± 1 mm/Ma, respectively. All data points (surface and core samples) but one, define a linear correlation in the Ln ( 230 Th/ 232 Th) - Ln [( 234 U) excess ( 238 U)] diagram. This correlation indicates that for all points the U-Th system remained closed after the Fe-Mn layer precipitated, and that the different samples possessed the same initial Uranium and thorium isotope ratios. Furthermore, these results show that the preserved surface of this Fe-Mn crust may not be the present-day growth surface, and that the thorium and uranium isotopic ratios of seawater in west equatorial Pacific have not changed during the past 150 ka. The initial thorium activity ratio is estimated from the correlation obtained between Ln( 230 Th/ 232 Th) and Ln [( 234 U) excess /( 238 U)

  8. Binary and ternary fission yields induced by 12C and 20Ne ions on 238U targets

    International Nuclear Information System (INIS)

    Otto, R.J.

    1974-01-01

    Evidence for ternary fission of 250 Cf* and 258 No* compound nuclei has been found. Relative cross section data for nuclides with masses between 24 Na and 161 Tb have been determined for 12 C bombardments of natural uranium at laboratory energies of 122 MeV, 113 MeV and 105 MeV. Relative cross section data for 8 nuclides between 24 Na and 66 Ni were sought for 20 Ne bombardments of natural uranium at 150 MeV laboratory energies. The binary fission fragment mass distribution for 238 U( 12 C,f) was determined by analysis of fission fragment recoil collection foils using radiochemical techniques and high resolution gamma ray spectroscopy. The results indicated the existence of a ternary fission branch similar to mass distributions obtained for He induced fission of Th, U, and Pu nuclei at intermediate energies. Comparison of the data with He induced ternary fission data obtained previously in this laboratory indicated an increase in the ternary fission probability with increasing Z 2 /A of the compound nucleus and with excitation energy. A shift of the binary-ternary fission product intersection point to lower mass numbers with increasing Z 2 /A and excitation energy of the compound nucleus was also observed. (Diss. Abstr. Int., B)

  9. Neutron scattering cross sections for 232Th and 238U inferred from proton scattering and charge exchange measurements

    International Nuclear Information System (INIS)

    Hansen, L.F.; Grimes, S.M.; Pohl, B.A.; Poppe, C.H.; Wong, C.

    1980-01-01

    Differential cross sections for the (p,n) reactions to the isobaric analog states (IAS) of 232 Th and 238 U targets were measured at 26 and 27 MeV. The analysis of the data was done in conjunction with the proton elastic and inelastic (2 + , 4 + , 6 + ) differential cross sections measured at 26 MeV. Because collective effects are important in this mass region, deformed coupled-channels calculations were carried out for the simultaneous analysis of the proton and neutron outgoing channels. The sensitivity of the calculations was studied with respect to the optical model parameters used in the calculations, the shape of the nuclear charge distribution, the type of coupling scheme assumed among the levels, the magnitude of the deformation parameters, and the magnitude of the isovector potentials, V 1 and W 1 . A Lane model-consistent analysis of the data was used to infer optical potential parameters for 6- to 7-MeV neutrons. The neutron elastic differential cross sections obtained from these calculations are compared with measurements available in the literature, and with results obtained using neutron parameters from global sets reported at these energies. 7 figures, 3 tables

  10. Photo-fission Product Yield Measurements at Eγ=13 MeV on 235U, 238U, and 239Pu

    Science.gov (United States)

    Tornow, W.; Bhike, M.; Finch, S. W.; Krishichayan, Fnu; Tonchev, A. P.

    2016-09-01

    We have measured Fission Product Yields (FPYs) in photo-fission of 235U, 238U, and 239Pu at TUNL's High-Intensity Gamma-ray Source (HI γS) using mono-energetic photons of Eγ = 13 MeV. Details of the experimental setup and analysis procedures will be discussed. Yields for approximately 20 fission products were determined. They are compared to neutron-induced FPYs of the same actinides at the equivalent excitation energies of the compound nuclear systems. In the future photo-fission data will be taken at Eγ = 8 . 0 and 10.5 MeV to find out whether photo-fission exhibits the same so far unexplained dependence of certain FPYs on the energy of the incident probe, as recently observed in neutron-induced fission, for example, for the important fission product 147Nd. Work supported by the U. S. Dept. of Energy, under Grant No. DE-FG02-97ER41033, and by the NNSA, Stewardship Science Academic Alliances Program, Grant No. DE-NA0001838 and the Lawrence Livermore, National Security, LLC under Contract No. DE-AC52-07NA27344.

  11. Neutron capture cross section measurements of $^{238}$U, $^{241}$Am and $^{243}$Am at n_TOF

    CERN Multimedia

    Koehler, P E; Plag, R

    The increase of the world energy demand and the need of low carbon energy sources have triggered the renaissance and/or enhancement of nuclear energy in many countries. Fundamental nuclear physics can contribute in a practical way to the sustainability and safety of the nuclear energy production and the management of the nuclear waste. There exists a series of recent studies which address the most relevant isotopes, decay data, nuclear reaction channels and energy ranges which have to be investigated in more detail for improving the design of different advanced nuclear systems [1] and nuclear fuel cycles [2]. In this proposal, we aim at the measurement of the neutron capture cross sections of $^{238}$U, $^{241}$Am and $^{243}$Am. All three isotopes are listed in the NEA High Priority Request List [37], are recommended for measurements [1] and play an important role in the nuclear energy production and fuel cycle scenarios. The measurements will provide as well valuable nuclear structure data necessary for the...

  12. Observation of an isomeric level in 239U by means of the 238U(n,γ)239U reaction

    International Nuclear Information System (INIS)

    Thomas, B.W.; Murray, J.; Rae, E.R.

    1970-01-01

    Low-energy-capture gamma-ray spectra ( 238 U up to a neutron energy of 350 eV. The data were obtained using a 25-cm 3 Ge(Li) detector at the Harwell 45 MeV Electron Linac. Capture events were recorded as functions of gamma-ray energy and neutron time-of-flight, and by suitable analysis of the data time-of-flight spectra have been obtained for individual gamma-rays. The strongest low-energy gamma-ray, at 134 keV, depopulates a level in 239 U at the same energy by an E2-transition to the ground state. The time-of-flight spectrum for this transition indicates that the 134-keV level is isomeric with a half-life of approximately 1 microsecond. This is evident from the long tails on the low-energy side of each resonance, which are not present for other regions of the gamma-ray spectrum. The possibility of using low-energy gamma-rays as a measure of the total capture cross-section is investigated by comparing the time-of-flight spectrum for the 134-keV transition with that for a Moxon-Rae detector under the same experimental conditions. (author)

  13. A Study of the Resonance Interaction Effect between 238U and 239Pu in Lower Energy Region

    International Nuclear Information System (INIS)

    Haeggblom, H.

    1968-12-01

    An investigation has been made of the statistical frequency function for the distances between the 238 U and the 239 Pu resonances in the region 4-244 eV. It is concluded that the frequency function is probably constant but that the distances diverge appreciably from a constant function in the actual case, and that the divergence is such that the interaction effect on the resonance integral is smaller than would be expected from statistical considerations. This is also confirmed by calculations on the interaction effect. These have been performed using three different methods, namely: a) considering the actual positions and widths of the resonances, b) assuming a constant frequency function for the resonance. spacing and applying a theory developed by Rowlands and E A Fischer. c) applying a simplified, approximate method for calculations based on the statistical theory. The calculations are made for two temperatures and two values of the plutonium enrichment. It is shown that the average cross sections are considerably larger than the statistical calculations indicate

  14. Determination of the fission products yields, lanthanide and yttrium, in the fission of 238U with neutrons of fission spectra

    International Nuclear Information System (INIS)

    Nicoli, I.G.

    1981-06-01

    A radiochemical investigation is performed to measure the cumulative fission product yields of several lantanides and yttrium nuclides in the 238 U by fission neutron spectra. Natural and depleted uranium are irradiated under the same experimental conditions in order to find a way to subtract the contribution of the 235 U fission. 235 U percentage in the natural uranium was 3.5 times higher than in the depleted uranium. Uranium oxides samples are irradiated inside the core of the Argonaut Reactor, at the Instituto de Engenharia Nuclear, and the lantanides and yttrium are chemically separated. The fission products gamma activities were detected, counted and analysed in a system constituted by a high resolution Ge(Li) detector, 4096 multichannel analyser and a PDP-11 computer. Cumulative yields for fission products with half-lives between 1 to 33 hours are measured: 93 Y, 141 La, 142 La, 143 Ce and 149 Nd. The chain total yields are calculated. The cumulative fission yields measured for 93 Y, 141 La, 142 La, 143 Ce and 149 Nd are 4,49%, 4,54%, 4,95%, 4,16% and 1,37% respectively and they are in good agreement with the values found in the literature. (Author) [pt

  15. A Study of the Resonance Interaction Effect between {sup 238}U and {sup 239}Pu in Lower Energy Region

    Energy Technology Data Exchange (ETDEWEB)

    Haeggblom, H

    1968-12-15

    An investigation has been made of the statistical frequency function for the distances between the {sup 238}U and the {sup 239}Pu resonances in the region 4-244 eV. It is concluded that the frequency function is probably constant but that the distances diverge appreciably from a constant function in the actual case, and that the divergence is such that the interaction effect on the resonance integral is smaller than would be expected from statistical considerations. This is also confirmed by calculations on the interaction effect. These have been performed using three different methods, namely: a) considering the actual positions and widths of the resonances, b) assuming a constant frequency function for the resonance. spacing and applying a theory developed by Rowlands and E A Fischer. c) applying a simplified, approximate method for calculations based on the statistical theory. The calculations are made for two temperatures and two values of the plutonium enrichment. It is shown that the average cross sections are considerably larger than the statistical calculations indicate.

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

    International Nuclear Information System (INIS)

    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 1.45mgkg -1 in lichen at 2.09E-04μgm -3 in air and 0.106mgkg -1 in lichen at 1.13E-05μgm -3 in air. The relationship of the uranium content in atmosphere and that in lichens was determined, C AIR =exp(1.1xC LICHEN -12). The possibility of separate identification of natural and man-made uranium in lichens was demonstrated in principle

  17. 230Th, 232Th and 238U determinations in phosphoric acid fertilizer and process products by ICP-MS

    International Nuclear Information System (INIS)

    Nascimento, Marcos R.L. do; Guerreiro, Luisa M.R.; Bonifacio, Rodrigo L.; Taddei, Maria H.T.

    2015-01-01

    Through processing of Santa Quiteria-CE mine phosphate rock, Brazil has established a project for production of phosphoric acid fertilizer and uranium as a by-product. Under leaching conditions of phosphate rock with sulfuric acid, which is the common route for preparing phosphoric acid fertilizer, a large part of uranium, thorium and their decay products naturally present in the rock are solubilized. In order to assess the contamination potential in phosphoric acid and others process products, this paper describes a previous precipitation and direct methods for routine analysis of thorium and uranium isotopes by ICP-MS. In all samples, 230 Th, 232 Th and 238 U were directly determined after dilution, except 230 Th in phosphoric acid loaded with uranium sample, which to overcome equipment contamination effect, was determined after its separation by oxalate precipitation using lanthanum as a carrier. The results obtained by the proposed method by ICP-MS, were in good agreement when compared to alpha spectrometry for 230 Th, and ICP-OES and spectrophotometry with arsenazo III for elementary uranium and thorium determinations. (author)

  18. Isotopic separation of 235U and 238U in an atomic beam with selective two-step photo-ionisation

    International Nuclear Information System (INIS)

    Boehm, H.D.V.

    1977-01-01

    The present work gives a report on investigations on isotope separation of 235 U and 238 U by means of selective two-stage photo-ionization on atomic uranium. An atomic beam of sufficient particle density was produced by dissociation of URe 2 in an electron beam heated tungsten furnace at a temperature of 2.500 k. A continuously operated rhodamin-69 dye laser with a maximum output of 120 mW and about 50 mHz band width in one-made operation was used for selective excitation from the ground state. From this state of excitation, ionization resulted achieving a light power of 1.8 W below 3030 A in the reaction volume. The measured separation factors show that the laser method enables the enrichment of uranium to the required valve of three or more percent 235 U for light water reactors in a single separation step. The hyperfine structure could be considerably better resolved compared to earlier investigations, so that it was possible for the first time to identify and measure hitherto unobserved weak components. (orig.) [de

  19. Behaviour of {sup 238}U, {sup 234}U, {sup 228}Ra and {sup 226}Ra in rock alterations: study of Morungaba granitoids, SP-Brazil and ground water in its fractures; Comportamento de {sup 238}U, {sup 234}U, {sup 228}Ra e {sup 226}Ra na alteracao de rochas: estudo dos granitoides de Morungaba (SP) e aguas subterraneas de suas fraturas

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Rosana N. dos [Pontificia Univ. Catolica de Sao Paulo, SP (Brazil). Dept. de Fisica]. E-mail: rosana@pucsp.br; Marques, Leila S. [Sao Paulo Univ., SP (Brazil). Inst. de Astronomia, Geofisica e Ciencias Atmosfericas. Dept. de Geofisica]. E-mail: leila@iag.usp.br

    2005-07-01

    This work presents the first results obtained on the investigation of the behavior of uranium and radium radioisotopes in the processes of weathering and rock-water interaction of Morungaba granitoids belonging to Meridional Pluton (Valinhos Town-SP-Brazil). Specific activities of {sup 238}U, {sup 234}U, {sup 228}Ra and {sup 226}Ra were determined in non altered granitoids (Group A), as well as in those affected by different degrees of weathering (Groups B, C and D). The uranium specific activities were determined by alpha spectrometry method, whereas for the determination of radium isotopes high resolution gamma-ray spectrometry technique was employed. The data indicate that {sup 238}U and {sup 234}U are in radioactive equilibrium in the fresh analyzed granitoids, but show a slight depletion of {sup 234}U in relation to {sup 238}U in the weathered rocks. The ({sup 226}Ra/{sup 238}U) and ({sup 226}Ra/{sup 234}U) activity ratios of all investigated rocks are similar, showing a significant {sup 226}Ra depletion, which is probably caused by its preferential leaching. These results indicate that even samples macroscopically classified as fresh rocks, their systems have been opened for some geochemical changes. The high ({sup 234}U/{sup 238}U) activity ratios of groundwaters which are found in the fractures of these granitoids suggest their prolonged residence times in the aquifer and/or their percolation by other rocks presenting different geochemical properties. (author)

  20. Determination of 234U and 238U activity concentrations in groundwaters from three deep wells drilled in Itu Intrusive Suite (SP)

    International Nuclear Information System (INIS)

    Souza, Francisca de

    2006-01-01

    Activity concentrations of ( 234 U) and ( 238 U) were determined in groundwaters drawn from three deep wells drilled in rocks from Itu Intrusive Suite (SP), two located in Salto town (S and SY wells) and the other one in Itu (I well). Sampling was done from September, 2004 to December, 2005, and twelve samples of each well were collected monthly. For those determinations alpha spectrometry technique was used, providing high precision results, as shown by the very good agreement of the data obtained in the analyses of 23 duplicates. The waters from the three wells presented a considerable enrichment of 234 U in relation to 238 U, indicating an important radioactive disequilibrium of these isotopes. In well I, the activity concentrations of ( 238 U) varied from (1,06 +- 0,03) to (2,1+- 0,2) mBq/L and those of ( 234 U) spanned from (3,1 +- 0,2) to (6,0 +- 0,4) mBq/L, whereas ( 234 U/ 238 U) activity ratios did not present significant variation, during the sampling time interval, presenting an average of 2,8 +- 0,1. The S waters showed the lowest uranium concentrations and the largest diversity of ( 238 U) and ( 234 U) activity concentrations, which varied from (0,26 +- 0,02) to (1,07+- 0,08) mBq/L and from (1,8 +- 0,1) to (7,0 +- 0,5) mBq/L, respectively, and also presented variable ( 234 U/ 238 U) activity ratios, spanning from (2,79 +- 0,07) to (8,1+- 0,3). In SY well, ( 238 U) activities varied between (0,8 +- 0,1) and (4,2 +- 0,3) mBq/L and those ones of ( 234 U) from (14 +- 1) to (53 +- 4) mBq/L, whereas ( 234 U/ 238 U) ratios fell in the interval from 12,6 +- 0,3 to 18,3 +- 0,4, with the highest activities of both radioisotopes registered during the dry season and the lowest ones in the rainy time period. The ( 234 U/ 238 U) activity ratios, which were invariable during sampling period of well I, indicated the contribution of rainfall to recharge the aquifer. The observed correlation between those ratios and uranium concentrations, for S and SY wells, showed

  1. A study on physical characteristics of supercritical light - water reactor loaded with (232U-238Th-238U) oxide fuel

    International Nuclear Information System (INIS)

    Kulikov, E. G.; Shmelev, A. N.; Apse, V. A.; Kulikov, G. G.

    2007-01-01

    The attractiveness of using (U-Th)-fuel in supercritical light water reactor is considered. The dilution of 2 33U in 2 38U is proposed with the purpose of increasing non-proliferation of this fissile isotope. Comparison of different fuel compositions is accomplished from the point of view of fissile isotope breeding and achieved burn-up; parasitic neutron absorption cross-sections are also compared. It is analyzed the impact for neutron balance of both cladding materials: zirconium alloy and stainless steel

  2. Comparison of activity concentration of 238U, 232Th and 40K in different Layers of subsurface Structures in Dei-Dei and Kubwa, Abuja, northcentral Nigeria

    International Nuclear Information System (INIS)

    Maxwell, Omeje; Wagiran, Husin; Ibrahim, Noorddin; Lee, Siak Kuan; Sabri, Soheil

    2013-01-01

    The study of activity concentration of 232 Th, 238 U and 40 K of rock samples from site one (S1L1–S1L11, 70 m) and site two (S2L1–S2L9, 60 m) boreholes in Dei-Dei and Kubwa was presented and the first time in the region to be compared. Activity concentrations were analysed using a high resolution co-axial HPGe gamma ray spectrometer system. The activity concentration ranges in site one borehole were from 45±1 to 98±6 Bq kg −1 for 232 Th, from 18±2 to 37±4 Bq kg −1 for 238 U and from 254 ±32 Bq kg −1 to 1195 ±151 Bq kg −1 for 40 K. The activity concentration ranges in site two borehole were from 32±3 to 84±7 Bq kg −1 for 232 Th, from 15±2 to 52±5 Bq kg −1 for 238 U and from 119±15 to 705±94 for 40 K Bq kg −1 . Significantly higher concentration of 232 Th and 238 U occurs in samples collected from S1L7, S1L11 and S2L1 layers. These zones experienced granitic intrusions produced by denudation and tectonism. 40 K in rock samples of S1L4 and S2L4 activity concentrations is close; it could be that biotite granitic intrusion that is inferred as the formation in that layer reflects the same activity of potassium in rock's radioactivity measurement. The area requires further investigation of soil geochemistry and activity concentration of radionuclides in groundwater. - Highlights: • Activity concentration of 238 U, 232 Th and 40 K was noted high. • The two boreholes show significant different concentrations of 238 U, 232 Th and 40 K. • The Th/U ratio was high in both, but distinctly higher in first borehole. • 232 Th was increasing with depth in site one almost 100%. • The radiological monitoring on groundwater is recommended

  3. Activity concentrations of 238U and 226Ra in scales formed on pipes of industrial boilers in the state of Pernambuco, Brazil

    International Nuclear Information System (INIS)

    Poggi, Claudia M.B.; Farias, Emerson E.G. de; Gazineu, Maria H.P.

    2015-01-01

    The procedures employed in the industry can generate significant amounts of solid, liquid and gaseous wastes that usually contain toxic or materials of difficulty degradation. One of the facts that contribute to the formation of such wastes is the generation of steam used in operating processes and industry segments. Currently, steam supplied by boilers is the most economical and practical mode of heat transfer in industrial processes. Due to the high temperature of water used in these processes, compounds which were previously soluble become insoluble, generating residues called scales. This material, which contains stable ions, can also present naturally occurring radionuclides such as 238 U and 226 Ra, which concentrate over time in piping and equipment surfaces. If not disposed correctly, this material also can contaminate the environment. The main origin of these radionuclides is the use of groundwater in industrial processes. Thus, in regions of naturally enriched in radionuclides such as the Region of Pernambuco, including the municipalities of Paulista and Goiana, there is a greater possibility of radioactive scale formation. Therefore, this study aimed to determine the activity concentrations of 238 U and 226 Ra present in the solid wastes generated by industries situated in Paulista and Goiana, in order to assess radionuclide disequilibrium. For the sake of comparison, scale samples collected from industries located in the municipality of Caruaru, far from the previous municipalities, were also analyzed. The determination of the activity concentrations for 238 U and 226 Ra was performed by High Resolution Gamma-Ray Spectrometry. Samples were collected, prepared, packed in plastic containers and set aside for a minimum time of 21 days, for the secular equilibrium to occur between 226 Ra and its short lived descendants. The counting time was 80,000 seconds. Gamma energies used for determination of activity concentrations were 1001 keV for 238 U, and 352 ke

  4. Bioaccumulation of polonium ({sup 210}Po) and uranium ({sup 234}U, {sup 238}U) in plants around phosphogypsum waste heap in Wislinka (northern Poland)

    Energy Technology Data Exchange (ETDEWEB)

    Borylo, A.; Skwarzec, B. [Gdansk Univ. (Poland). Faculty of Chemistry

    2011-07-01

    In the study the activities of polonium {sup 210}Po and uranium {sup 234}U, {sup 238}U in plants, collected near phosphogypsum waste heap in Wis'linka (northern Poland), were determined by using the alpha spectrometry. The obtained results revealed that the concentrations of {sup 210}Po, {sup 234}U, and {sup 238}U in the analyzed plants were differentiated. In the analyzed flora organisms the highest amounts of polonium and uranium were found in ruderal plant samples as well as willow samples (Salix viminalis) from protection zone of phosphogypsum waste heap. The concentrations of {sup 210}Po, {sup 234}U and {sup 238}U in the analyzed plants were higher in roots than in green parts of plants. The higher concentrations of {sup 210}Po and {sup 238}U radionuclides were estimated for hydrophyte (common sedge Carex nigra Reichard), the favourite habitat of which is particularly wet meadow and for plants collected in the vicinity of phosphogypsum waste heap. The major source of polonium and uranium in analyzed plants is root system. The values of {sup 234}U/ {sup 238}U activity ratio in all analyzed plants are closed to one, what indicated that source of uranium in analyzed plants is phosphogypsum. The highest uranium and polonium concentrations were characterized for plants, which are covered with tomentose. The comparability polonium and uranium contents were confirmed in edible plants, but higher accumulation was determined in ripe species than immature species of vegetables. The higher polonium and uranium concentrations were noticed in green parts of plant, the lower in roots. Polonium concentration in cultivated plants samples was not species diverse. Therefore, the significant source of polonium and uranium in analyzed plants is wet and dry atmospheric falls gathering the soil and air dust from phosphogypsum waste dump. The maximum {sup 210}Po and {sup 238}U radionuclides concentrations were found in green parts of red beet (Beta vulgaris esculenta), the

  5. Activity concentrations of {sup 238}U and {sup 226}Ra in scales formed on pipes of industrial boilers in the state of Pernambuco, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Poggi, Claudia M.B.; Farias, Emerson E.G. de, E-mail: claudiapoggi04@gmail.com, E-mail: emersonemiliano@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear; Franca, Elvis J.; Hazin, Clovis A., E-mail: chazin@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Gazineu, Maria H.P., E-mail: helena@unicap.br [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil). Centro de Ciencias e Tecnologia

    2015-07-01

    The procedures employed in the industry can generate significant amounts of solid, liquid and gaseous wastes that usually contain toxic or materials of difficulty degradation. One of the facts that contribute to the formation of such wastes is the generation of steam used in operating processes and industry segments. Currently, steam supplied by boilers is the most economical and practical mode of heat transfer in industrial processes. Due to the high temperature of water used in these processes, compounds which were previously soluble become insoluble, generating residues called scales. This material, which contains stable ions, can also present naturally occurring radionuclides such as {sup 238}U and {sup 226}Ra, which concentrate over time in piping and equipment surfaces. If not disposed correctly, this material also can contaminate the environment. The main origin of these radionuclides is the use of groundwater in industrial processes. Thus, in regions of naturally enriched in radionuclides such as the Region of Pernambuco, including the municipalities of Paulista and Goiana, there is a greater possibility of radioactive scale formation. Therefore, this study aimed to determine the activity concentrations of {sup 238}U and {sup 226}Ra present in the solid wastes generated by industries situated in Paulista and Goiana, in order to assess radionuclide disequilibrium. For the sake of comparison, scale samples collected from industries located in the municipality of Caruaru, far from the previous municipalities, were also analyzed. The determination of the activity concentrations for {sup 238}U and {sup 226}Ra was performed by High Resolution Gamma-Ray Spectrometry. Samples were collected, prepared, packed in plastic containers and set aside for a minimum time of 21 days, for the secular equilibrium to occur between {sup 226}Ra and its short lived descendants. The counting time was 80,000 seconds. Gamma energies used for determination of activity concentrations

  6. 230Th-238U disequilibrium systematics in oceanic tholeiites from 210N on the East Pacific Rise

    International Nuclear Information System (INIS)

    Newman, S.; Finkel, R.C.; MacDougall, J.D.

    1983-01-01

    Significant disequilibrium occurs between 230 Th and its parent, 238 U, in a suite of fresh basalt glasses from the RISE Project study area at 21 0 N on the East Pacific Rise. The ( 230 Th/ 232 Th) activity ratios observed for eight of nine samples from the crest of the axis at this site are constant within analytical uncertainty, with a value of 1.22. This observed homogeneity of ( 230 Th/ 232 Th) has two possible interpretations. First, the measured ( 230 Th/ 232 Th) can be considered to indicate a mantle-source for the RISE basalts with Th/U of 2.5. This interpretation, however, conflicts with the proposed correlation between ( 230 Th/ 232 Th) and 87 Sr/ 86 Sr which predicts that ( 230 Th/ 232 Th) should equal 1.33 at the RISE site. A second possible interpretation is that radioactive decay of 230 Th, in the basalts themselves or in a magma chamber, has decreased ( 230 Th/ 232 Th) from 1.33 to the observed values. The required time span is 11,000 to > 100,000 years. However, petrologic arguments rule against long residence time in a magma chamber, and the spreading rate of this section of the East Pacific Rise (6 cm/yr) predicts that the maximum age for axis basalts is 27,000 years. Both interpretations of the measured ( 230 Th/ 232 Th) imply a low Th/U ratio for the RISE basalt source and suggest that the MORB source at this location is depleted in Th with respect to U relative to primitive mantle or bulk earth. (orig./WL)

  7. Search for superheavy elements in the reaction 238U+9.6 MeV/N 63Cu,65Cu

    International Nuclear Information System (INIS)

    Esterlund, R.A.; Molzahn, D.; Brandt, R.; Patzelt, P.; Vater, P.; Boos, A.H.

    1976-01-01

    According to calculations of NIX and others, the formation of superheavy elements might occur in heavy-ion reaction systems such as the one under investigation in the present work i.e., 238 U + 63 Cu and 65 Cu at 9.6 MeV/nucleon. Since previous experiments have indicated that upper limits to the production cross-section for superheavy elements are extremely low, two rather long irradiations of 27 hrs and 42 hrs, respectively, have been carried out at the University of Manchester LINAC. The first run has already been reported on in the literature. In the case of the second run, after chemical separation into HgS, CdS, and La(OH) 3 fractions, the samples were assayed simultaneously and continuously over a period of 6 months for alpha- and spontaneous-fission activity, using Si surface-barrier detector. Each sample was at the same time mounted on mica, for the purpose of scanning for fission tracks at a later date. No indications from the data have so far been found that superheavy elements were produced. Possible reasons for the failure to detect superheavy elements in this experiment are: The half-life of any product is either too short (a few hours) or too long (a few years); the chemical properties of the superheavy elements are very different from those predicted; the position of the superheavy island is not where it is commonly assumed to be and may, for example, be at Z>=114 and N>=184, as predicted by ROUBEN et al. (T.G.)

  8. The clinical characteristics of the radiation pneumonia

    International Nuclear Information System (INIS)

    Zhang Fuzheng; Wang Mingzhi; Chen Jianjiang; Wang Zhongxiang; Mao Yongjie

    2000-01-01

    Objective: To analyse the clinical characteristics of the radiation pneumonia, sum the experience and the basis of the radiation pneumonia for its prevention and treatment. Method: Twenty three cases with radiation pneumonia from 1991 to 1998 were retrospectively analysed. Its clinical manifestation, chest X-ray, thoracic CT and blood routine were evaluated. Result: The acute manifestation was fever, cough, dyspnea, and the chronic manifestation was cough and insufficiency of pulmonary function. Conclusion: The prevention of radiation pneumonia is more important, high dose cortical steroids and antibiotics were prescribed during the acute stage and the chronic radiation pneumonia is irreversible

  9. A statistical study of {sup 238}U and {sup 234}U/{sup 238}U distributions in coral samples from the Egyptian shoreline of the north-western Red sea and in fossil mollusk shells from the Atlantic coast of High Atlas in Morocco: implications for {sup 230}Th/{sup 234}U dating

    Energy Technology Data Exchange (ETDEWEB)

    Choukri, A.; Hakam, O.K. [Lab. des Faibles Radioactivites et d' Environnements, UFR: Faibles Radioactivites, Mathematiques physiques et environnement, Kenitra (Morocco); Reyss, J.L. [Lab. des Sciences de Climat et de l' Environnement, Domaine du CNRS, Gif sur Yvette (France); Plaziat, J.C. [Univ. de Paris-Sud, Dept. des Sciences de la Terre, Orsay (France)

    2002-07-01

    In this work, radiochemical analysis results of 126 uncrystallized coral samples from the Egyptian shoreline of northwestern Red Sea and 120 fossil mollusk shell samples from the Atlantic coast of Moroccan High Atlas at the North of Agadir City in Morocco are presented and discussed. The coral samples were collected in Egypt from the emerged coral reef terraces over 500 km from The Ras Gharib-Ras Shukeir depression (28 10') in the north to Wadi Lahami (north of Ras Banas, 24 10') in the south. The fossil mollusk shells were collected in Morocco from Agadir-Harbour in the south to Tamri village in the north extending over about 50 km. The statistical distributions of results ({sup 238}U content, {sup 234}U/{sup 238}U activity ratio and ages) obtained on the dated materials in the two different regions were compared for three fossil sea levels corresponding to three different climatic stages (Holocene, 5e, 7 and/or 9) in the aim to establish methodological criteria for judging validity of the measured ages. For corals, {sup 238}U content varies in narrow interval around the same average value of 3 ppm for the three sea levels, the calculated initial {sup 234}U/{sup 238}U values are in agreement with the actual sea water ratio (1.15) with some values slightly higher than for the older sea levels. The obtained ages are in good agreement with the ages reported previously for the three emerged fossil sea levels on unrecrystallized corals by alpha spectrometry and by mass spectrometry. For mollusk shells, except for Holocene sea level, {sup 238}U and initial {sup 234}U/{sup 238}U activity ratios vary for the older levels in wide intervals, independent of species and calcite contents of samples. The high {sup 238}U contents and {sup 234}U/{sup 238}U activity ratio are due eventually to a post-incorporation of secondary uranium from sea water or from continental waters drained away rivers. This incorporation leads to a rejuvenation of mollusk shell ages and is

  10. Mass dependence of azimuthal asymmetry in the fission of {sup 232}Th and {sup 233,235,236,238}U by polarized photons

    Energy Technology Data Exchange (ETDEWEB)

    Denyak, V.V. [National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Kharkiv (Ukraine); Pele Pequeno Principe Research Institute, Curitiba (Brazil); Khvastunov, V.M. [National Science Center ' ' Kharkov Institute of Physics and Technology' ' , Kharkiv (Ukraine); Paschuk, S.A. [Federal University of Technology - Parana, Curitiba (Brazil); Schelin, H.R. [Federal University of Technology - Parana, Curitiba (Brazil); Pele Pequeno Principe Research Institute, Curitiba (Brazil)

    2013-04-15

    Fission of the even-even nuclei {sup 232}Th, {sup 236,238}U and even-odd nuclei {sup 233,235}U by linearly polarized photons has been studied at excitation energies in the region of a giant dipole resonance. The performed investigations unambiguously showed the existence of the fragment mass dependence of the cross section azimuthal asymmetry in the photofission of {sup 236}U and {sup 238}U. In addition, the obtained results provided the first evidence for the possible difference between the asymmetry values in asymmetric and symmetric mass distribution regions in the case of {sup 236}U. The measured cross section azimuthal asymmetry of the fission of {sup 232}Th does not show any fragment mass dependence. In the even-odd nuclei {sup 233}U and {sup 235}U the difference between the far-asymmetric and other mass distribution regions was also observed but with the statistical uncertainty not small enough for definitive conclusion. (orig.)

  11. Mass dependence of azimuthal asymmetry in the fission of 232Th and 233,235,236,238U by polarized photons

    International Nuclear Information System (INIS)

    Denyak, V.V.; Khvastunov, V.M.; Paschuk, S.A.; Schelin, H.R.

    2013-01-01

    Fission of the even-even nuclei 232 Th, 236,238 U and even-odd nuclei 233,235 U by linearly polarized photons has been studied at excitation energies in the region of a giant dipole resonance. The performed investigations unambiguously showed the existence of the fragment mass dependence of the cross section azimuthal asymmetry in the photofission of 236 U and 238 U. In addition, the obtained results provided the first evidence for the possible difference between the asymmetry values in asymmetric and symmetric mass distribution regions in the case of 236 U. The measured cross section azimuthal asymmetry of the fission of 232 Th does not show any fragment mass dependence. In the even-odd nuclei 233 U and 235 U the difference between the far-asymmetric and other mass distribution regions was also observed but with the statistical uncertainty not small enough for definitive conclusion. (orig.)

  12. Investigation of the 234U/238U disequilibrium in the natural waters of the Santa Fe River basin north-central Florida

    International Nuclear Information System (INIS)

    Briel, L.I.

    1976-01-01

    Typical surface water masses in the Santa Fe basin are characterized by a 238 U concentration of 0.224 +- .014 ppB and a 234 U/ 238 U activity ratio of 1.081 +- .038. The Floridan aquifer in this area is represented by at least two distinct regimes of ground water. The effluent from the Poe Springs group has a nominal uranium concentration of 0.938 +- .014 ppB and an activity ratio of 0.900 +- .012, while the effluent from the Ichetucknee Springs group has a nominal uranium concentration of 0.558 +- .018 ppB and an activity ratio of 0.707 +- .022. The effluent from ten additional springs in the Santa Fe system can be represented by hypothetical mixtures of these two ground water regimes and a hypothetical surface water component, which may reflect the extent of local recharge to the aquifer in different parts of the basin

  13. Distribution of radioactive pollution of 238U, 232Th, 40K and 137Cs in northwestern coasts of Persian Gulf, Iran

    International Nuclear Information System (INIS)

    Reza Abdi, Mohammad; Kamali, Mehdi; Vaezifar, Sedigheh

    2008-01-01

    A reconnaissance study has been made of the distribution of 238 U, 232 Th, 40 K and 137 Cs and geochemical features in soils and sediments samples at various locations in the northwestern coast of Persian Gulf. Activity concentration levels due to radionuclides were measured in 30 soil and sediment samples collected from this region. From the measured spectra, activity concentrations were determined for 40 K (range from 146 to 500 Bq kg -1 ), 137 Cs (from 5 to 20 Bq kg -1 ), 238 U (from 21 to 65 Bq kg -1 ) and 232 Th (from 15 to 45 Bq kg -1 ) with lowest limit detection (LLD) of 68, 3.2, 4.3 and 4.3 Bq kg -1 , respectively. The dose rate from ambient air at the soil ranges was between 19 and 58 nGy h -1 with an average of 37.41 ± 9.66 nGy h -1

  14. Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN – n_TOF

    Directory of Open Access Journals (Sweden)

    Diakaki M.

    2016-01-01

    Full Text Available The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN – n_TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards.

  15. Photofission cross-section ratio measurement of 235U/238U using monoenergetic photons in the energy range of 9.0-16.6 MeV

    Science.gov (United States)

    Krishichayan; Bhike, Megha; Finch, S. W.; Howell, C. R.; Tonchev, A. P.; Tornow, W.

    2017-05-01

    Photofission cross-section ratios of 235U and 238U have been measured using monoenergetic photon beams at the HIγS facility of TUNL. These measurements have been performed in small energy steps between 9.0 and 16.6 MeV using a dual-fission ionization chamber. Measured cross-section ratios are compared with the previous experimental data as well as with the recent evaluated nuclear data library ENDF.

  16. Determination of the quadrupole moment of the fission-isomeric state in 238U by a modified charge-plunger method

    International Nuclear Information System (INIS)

    Pedersen, J.; Goerlach, U.; Habs, D.; Just, M.; Metag, V.; Mosler, E.; Schukraft, J.; Singer, P.; Specht, H.J.; Ulfert, G.

    1978-01-01

    A modified version of the charge plunger method has been developed which, by utilizing electrostatic fields, renders possible the separation of low- and high-charge recoil ions over short flight distances. With this technique the quadrupole moment of the 200 ns fission isomer in 238 U has been determined to be (29 +- 3) b. The corresponding deformation of c/a = (1.8 +- 0.1) provides another quantitative proof for shape isomerism in the actinide region. (orig.) [de

  17. Accumulation of 226Ra, 238U and 230Th by wetland plants in a vicinity of U-mill tailings at Zirovski vrh (Slovenia)

    International Nuclear Information System (INIS)

    Marko Cerne; Borut Smodis; Marko Strok; Radojko Jacimovic

    2010-01-01

    The impact of a U-mill tailing on radionuclide accumulation by plants was assayed. In particular, a preliminary screening of 226 Ra, 238 U and 230 Th in Marsh marigold (Caltha palustris L.), soft rush (Juncus effusus L.) and Tall Moor grass (Molinia arundinacea (L.) Moench) grown in a marsh habitat is presented. Activity concentrations for the studied radionuclides and their transfer factors for the particular plants are shown and discussed. (author)

  18. A comparative study of 232Th and 238U activity estimation in soil samples by gamma spectrometry and Neutron Activation Analysis (NAA) technique

    International Nuclear Information System (INIS)

    Rekha, A.K.; Anilkumar, S.; Narayani, K.; Babu, D.A.R.

    2012-01-01

    Radioactivity in the environment is mainly due to the naturally occurring radionuclides like uranium, thorium with their daughter products and potassium. Even though Gamma spectrometry is the most commonly used non destructive method for the quantification of these naturally occurring radionuclides, Neutron Activation Analysis (NAA), a well established analytical technique, can also be used. But the NAA technique is a time consuming process and needs proper standards, proper sample preparation etc. In this paper, the 232 Th and 238 U activity estimated using gamma ray spectrometry and NAA technique are compared. In the case of direct gamma spectrometry method, the samples were analysed after sealing in a 250 ml container. Whereas for the NAA, about 300 mg of each sample, after irradiation were subjected to gamma spectrometry. The 238 U and 232 Th activities (in Bq/kg) in samples were estimated after the proper efficiency correction and were compared. The estimated activities by these two methods are in good agreement. The variation in 238 U and 232 Th activity values are within ± 15% which are acceptable for environmental samples

  19. Assessment of annual effective dose from 238U and 226Ra due to consumption of foodstuffs by inhabitants of Tehran city (IR)

    International Nuclear Information System (INIS)

    Hosseini, T.; Fathivand, A. A.; Abbasisiar, F.; Karimi, M.; Barati, H.

    2006-01-01

    The concentrations of 238 U and 226 Ra were determined in different foodstuffs purchased from markets in Tehran. Determinations of the radionuclides have been carried out using alpha spectrometry technique, on samples of egg, lentil, potato, rice, soya, spinach, tea and wheat. Average concentrations of natural radionuclides and foodstuff consumption rate were used to assess annual intake and based on intake values, the annual effective ingestion dose has been estimated for Tehran city residents. The measurement results show that soya has the maximum concentration of 238 U equal to 15.6 ± 2.6 mBq kg -1 and tea has the maximum concentration of 226 Ra equal to 1153.3 ± 265.3 mBq kg -1 . Besides, the maximum annual effective dose from 238 U and 226 Ra were assessed to be 2.88 x 10 -2 ±7.20 x 10 -3 and 2.15 ± 0.54 μSv, respectively, from wheat samples. (authors)

  20. Charge-state distribution measurements of ^{238}U and ^{136}Xe at 11  MeV/nucleon using gas charge stripper

    Directory of Open Access Journals (Sweden)

    H. Kuboki

    2010-09-01

    Full Text Available The charge-state distributions and equilibrium charge states of uranium (^{238}U and xenon (^{136}Xe ions at 11  MeV/nucleon were determined using a gas charge stripper. A differential pumping system facilitated the increase of the nitrogen gas thickness up to 1.3  mg/cm^{2}, which is sufficient for the most probable charge state to attain equilibrium. The charge states of ^{238}U attain equilibrium at 56.0, 56.6, and 55.7 in N_{2}, Ar, and CO_{2} media with thicknesses of 125, 79, and 126  μg/cm^{2}, respectively, while those of ^{136}Xe attain equilibrium at 40.5, 40.1, and 40.3 in N_{2}, Ar, and CO_{2} media with thicknesses of 163, 95, and 139  μg/cm^{2}, respectively. The equilibrium charge states of ^{136}Xe are acceptable for acceleration by the subsequent cyclotron. The measured data of ^{238}U were used to devise an empirical formula for the prediction of the equilibrium charge state in gaseous media over the energy region of 0.01–60  MeV/nucleon. The equilibrium charge state of ^{136}Xe as predicted by the devised formula is in good agreement with the data.

  1. 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.

  2. Double beta decay of Uranium-238: Proton reactions of 238U in 5--12 MeV range. Final report, April 15, 1987--March 31, 1992

    International Nuclear Information System (INIS)

    Turkevich, A.; Economou, T.E.

    1993-01-01

    This report is in two parts. The first part reports on the experimental work determining the half-life for double beta decay of 238 U to 238 PU to be (2.0 ± 0.6) x 10 21 years. This is the first evidence for a third mode of decay of this heaviest naturally occurring nucleus. This rate is about 10 6 times slower than spontaneous fission, which itself is about 10 6 times slower than alpha decay. The implication of this double beta decay to neutrino masses depends on uncertain theoretical calculations of the rate for such a heavy nucleus. The second part reports on yields of principal fission products from 5.6, 7.3, 9.4, and 11.5 MeV proton interactions with 238 U. The yields at 11.5 MeV are similar to those from 14 MeV neutron fission of 238 U. At the same time, the production cross sections of 238 Np at the same energies are determined. This nuclide is produced as often as fission at the lowest energy but only 3.8% as often at the highest energy

  3. Quantification of 235U and 238U activity concentrations for undeclared nuclear materials by a digital gamma-gamma coincidence spectroscopy.

    Science.gov (United States)

    Zhang, Weihua; Yi, Jing; Mekarski, Pawel; Ungar, Kurt; Hauck, Barry; Kramer, Gary H

    2011-06-01

    The purpose of this study is to investigate the possibility of verifying depleted uranium (DU), natural uranium (NU), low enriched uranium (LEU) and high enriched uranium (HEU) by a developed digital gamma-gamma coincidence spectroscopy. The spectroscopy consists of two NaI(Tl) scintillators and XIA LLC Digital Gamma Finder (DGF)/Pixie-4 software and card package. The results demonstrate that the spectroscopy provides an effective method of (235)U and (238)U quantification based on the count rate of their gamma-gamma coincidence counting signatures. The main advantages of this approach over the conventional gamma spectrometry include the facts of low background continuum near coincident signatures of (235)U and (238)U, less interference from other radionuclides by the gamma-gamma coincidence counting, and region-of-interest (ROI) imagine analysis for uranium enrichment determination. Compared to conventional gamma spectrometry, the method offers additional advantage of requiring minimal calibrations for (235)U and (238)U quantification at different sample geometries. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  4. Clinical characteristics of subacute radiation sickness

    International Nuclear Information System (INIS)

    Jiang Benrong; Ye Genyao; Huang Shimin

    1991-01-01

    The clinical characteristics, diagnosis and differential diagnosis of subacute radiation sickness are analysed and discussed in this paper on the basis of clinical data from cases in a 137 Cs source accident in Mudanjiang and of a review of the literature. We consider that the subacute radiation sickness is a whole body disease caused by comparatively large dose of continuous or intermittent external irradiation in several weeks or months. it must be differentiated from acute radiation sickness, chronic radiation sickness, idiopathic aplastic anemia and other hematological diseases, such as paroxysmal nocturnal hemoglobinuria, acute leukemia and myelodysplastic syndrome

  5. 238U series isotopes and 232Th in carbonates and black shales from the Lesser Himalaya: implications to dissolved uranium abundances in Ganga-Indus source waters

    International Nuclear Information System (INIS)

    Singh, S.K.; Dalai, Tarun K.; Krishnaswami, S.

    2003-01-01

    238 U and 232 Th concentrations and the extent of 238 U- 234 U- 230 Th radioactive equilibrium have been measured in a suite of Precambrian carbonates and black shales from the Lesser Himalaya. These measurements were made to determine their abundances in these deposits, their contributions to dissolved uranium budget of the headwaters of the Ganga and the Indus in the Himalaya and to assess the impact of weathering on 238 U- 234 U- 230 Th radioactive equilibrium in them. 238 U concentrations in Precambrian carbonates range from 0.06 to 2.07 μg g -1 . The 'mean' U/Ca in these carbonates is 2.9 ng U mg -1 Ca. This ratio, coupled with the assumption that all Ca in the Ganga-Indus headwaters is of carbonate origin and that U and Ca behave conservatively in rivers after their release from carbonates, provides an upper limit on the U contribution from these carbonates, to be a few percent of dissolved uranium in rivers. There are, however, a few streams with low uranium concentrations, for which the carbonate contribution could be much higher. These results suggest that Precambrian carbonates make only minor contributions to the uranium budget of the Ganga-Indus headwaters in the Himalaya on a basin wide scale, however, they could be important for particular streams. Similar estimates of silicate contribution to uranium budget of these rivers using U/Na in silicates and Na* (Na corrected for cyclic and halite contributions) in river waters show that silicates can contribute significantly (∼40% on average) to their U balance. If, however, much of the uranium in these silicates is associated with weathering resistant minerals, then the estimated silicate uranium component would be upper limits. Uranium concentration in black shales averages about 37 μg g -1 . Based on this concentration, supply of U from at least ∼50 mg of black shales per liter of river water is needed to balance the average river water U concentration, 1.7 μg L -1 in the Ganga-Indus headwaters

  6. Some characteristics and effects of natural radiation

    International Nuclear Information System (INIS)

    Mc Laughlin, J.P.

    2015-01-01

    Since life first appeared on the Earth, it has, in all its subsequent evolved forms including human, been exposed to natural radiation in the environment both from terrestrial and extra-terrestrial sources. Being an environmental mutagen, ionising natural radiation may have played a role of some significance in the evolution of early life forms on Earth. It has been estimated by United Nations Scientific Committee on the Effects of Atomic Radiation that at the present time, exposure to natural radiation globally results in an annual average individual effective dose of about 2.4 mSv. This represents about 80 % of the total dose from all sources. The three most important components of natural radiation exposure are cosmic radiation, terrestrial radioactivity and indoor radon. Each of these components exhibits both geographical and temporal variabilities with indoor radon exposure being the most variable and also the largest contributor to dose for most people. In this account, an overview is given of the characteristics of the main components of the natural radiation environment and some of their effects on humans. In the case of cosmic radiation, these range from radiation doses to aircrew and astronauts to the controversial topic of its possible effect on climate change. In the case of terrestrial natural radiation, accounts are given of a number of human exposure scenarios. (author)

  7. Biological availability of 238U, 234U and 226Ra for wild berries and meadow grasses in natural ecosystems of Belarus

    International Nuclear Information System (INIS)

    Sokolik, G.A.; Ovsiannikova, S.V.; Voinikava, K.V.; Ivanova, T.G.; Papenia, M.V.

    2014-01-01

    This work is devoted to investigation of behavior of 234 U, 238 U and 226 Ra by determining the soil to plant transfer under different natural conditions such as forest or swamped areas and meadow lands with different soil types. The paper summarizes the data on investigation of uranium and radium uptake by wild berries and natural meadow grasses in the typical conditions of Belarus. Parameters characterizing the biological availability of 234 U, 238 U and 226 Ra for bilberry (Vaccinium myrtillus), lingonberry (Vaccinium viti-idaea), blueberry (Vaccinium iliginosum) and cranberry (Vaccinium oxycoccus palustris) as well as for widely occurring mixed meadow vegetation, which belongs to the sedge-grass or grass-sedge associations and forbs, have been established. In the sites under investigation, the deposition levels of 238+239+240 Pu were less than 0.37 kBq m −2 and 137 Cs deposition ranged between less than 0.37 and 37 kBq m −2 . It was found that activity concentrations of radionuclides in berries varied in the ranges of 0.037–0.11 for 234 U, 0.036–0.10 for 238 U and 0.11–0.43 Bq kg −1 for 226 Ra, but in the mixed meadow grasses they were 0.32–4.4, 0.24–3.9 and 0.14–6.9 Bq kg −1 accordingly. The 234 U/ 238 U activity ratios were 1.02 ± 0.01 for wild berries, 1.20 ± 0.09 for underground meadow grasses and 1.02 ± 0.02 for proper soils. The concentration ratios (CRs, dry weight basis) of 234 U and 238 U for mixed meadow grasses were 0.036–0.42 and 0.041–0.46 respectively. The correspondent geometric means (GM) were 0.13 and 0.15 with geometric standard deviations (GSD) of 2.4. The CRs of 226 Ra for meadow grasses were 0.031–1.0 with GM 0.20 and GSD 2.6. The CRs of 234 U, 238 U and 226 Ra for wild berries ranged within 0.0018–0.008 (GM is 0.0034, GSD is 1.8), 0.0018–0.008 (GM is 0.0035, GSD is 1.8) and 0.005–0.033 (GM is 0.016, GSD is 2.1) accordingly. The highest CR values of uranium for mixed meadow grasses were found in the sites

  8. Characteristics of radiation protection legislation

    International Nuclear Information System (INIS)

    Puig Cardozo, Diva E.

    2001-01-01

    The laws on radiological protection have special characteristics. They can exist laws that regulate dangerous activities that will be also applicable, if it corresponds to the activities that involve radioactive materials. But a law of radiological protection should exist. It foresees the existence of an appropriate regulatory body and specialized institutions, definitions, infractions and sanctions then the respective regulations will be elaborated for the different applications. The objective is to contribute to the development of the nuclear energy in the country and to provide the regulatory basis that assures a reasonable security for radioactive installations. The essential objectives of these laws are: 1. to establish the legislative framework for the development and employment of nuclear energy, without risks, according with treaties and conventions that the countries have approved. 2. To fix the fundamental principles and the conditions of their setting in practice allowing to a specific regulation determining application procedures. 3. To create a structure of regulation of enough authority to be able to control and to watch over in an effective way the authorized activities 4. To guarantee an appropriate financial protection against the derived damages of accidents or nuclear incidents. (author)

  9. Origin, characteristics and detection of nuclear radiation

    International Nuclear Information System (INIS)

    Goettel, K.

    1975-06-01

    The report is an introduction into the physical principles of radiation protection. After a brief summary of the most significant experimental results and data on the atomic structure of the matter and after explaining the principles of atomic and nuclear structure, radioactive decay and its laws are dealt with. This is followed by a representation of the characteristics of nuclear radiation, its interaction with the matter as well as the biological effects. After a description of the measurement units for radioactivity and doses the most inportant methods for radiation detection and the principles of how detectors function are explained. (ORU/LN) [de

  10. Exploratory study of fission product yields of neutron-induced fission of 235U , 238U , and 239Pu at 8.9 MeV

    Science.gov (United States)

    Bhatia, C.; Fallin, B. F.; Gooden, M. E.; Howell, C. R.; Kelley, J. H.; Tornow, W.; Arnold, C. W.; Bond, E.; Bredeweg, T. A.; Fowler, M. M.; Moody, W.; Rundberg, R. S.; Rusev, G. Y.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Macri, R.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.

    2015-06-01

    Using dual-fission chambers each loaded with a thick (200 -400 -mg /c m2) actinide target of 235 ,238U or 239Pu and two thin (˜10 -100 -μ g /c m2) reference foils of the same actinide, the cumulative yields of fission products ranging from 92Sr to 147Nd have been measured at En= 8.9 MeV . The 2H(d ,n ) 3He reaction provided the quasimonoenergetic neutron beam. The experimental setup and methods used to determine the fission product yield (FPY) are described, and results for typically eight high-yield fission products are presented. Our FPYs for 235U(n ,f ) , 238U(n ,f ) , and 239Pu(n ,f ) at 8.9 MeV are compared with the existing data below 8 MeV from Glendenin et al. [Phys. Rev. C 24, 2600 (1981), 10.1103/PhysRevC.24.2600], Nagy et al. [Phys. Rev. C 17, 163 (1978), 10.1103/PhysRevC.17.163], Gindler et al. [Phys. Rev. C 27, 2058 (1983), 10.1103/PhysRevC.27.2058], and those of Mac Innes et al. [Nucl. Data Sheets 112, 3135 (2011), 10.1016/j.nds.2011.11.009] and Laurec et al. [Nucl. Data Sheets 111, 2965 (2010), 10.1016/j.nds.2010.11.004] at 14.5 and 14.7 MeV, respectively. This comparison indicates a negative slope for the energy dependence of most fission product yields obtained from 235U and 239Pu , whereas for 238U the slope issue remains unsettled.

  11. Temporal evolution of natural radionuclides distributions 238U, 234Th, 226Ra, 228Ra, 210Pb and 210Po in the Bransfield strait, Antarctica peninsula

    International Nuclear Information System (INIS)

    Lapa, Flavia Valverde

    2013-01-01

    Research on the distribution of natural radionuclides in Antarctica is rare and thus, there is great interest in to know their occurrence and factors related to its mobilization, transference and accumulation in this extremely fragile environment. Natural radionuclides have been used intensively as tracers in the ocean, helping to better understand processes as sinking and particle resuspension, water masses mixture and oceanic circulation. 234 Th (t½ = 24.1 days) is a particle-reactive radionuclide produced continuously in seawater by the decay of its soluble precursor conservative with salinity 238 U (t½ = 4.5 10 9 years). Since 234 Th presents relatively short half-life, it is used to quantify processes that occur in temporal scale varying from days to weeks. The disequilibrium 234 Th/ 238 U in the surface ocean has been applied to estimate carbon fluxes exported via sinking material. The flux of particles biologically productive out of the euphotic zone in the Southern Ocean has special attention due to its importance in the control of CO 2 atmospheric concentrations. The radionuclides 210 Pb (t½ = 22.3 years) and 210 Po (t½ = 138 days) are also particle-reactive. The disequilibrium 210 Po/ 210 Pb has been used to estimate fluxes of particles exported in the ocean in the time scale of weeks. The long-lived Ra isotopes, 226 Ra (t½ = 1,600 years) and 228 Ra (t½ = 5.75 years) are soluble in seawater, presenting unique properties that make them excellent tracers of water masses. This research work had the aim to study the distributions of natural radionuclides 238 U, 234 Th, 22 '6Ra, 22 '8Ra, 210 Pb and 210 Po in the Bransfield Strait during 2 samplings carried out in the 2011 Austral Summer (OPERANTAR XXIX and XXX). (author)

  12. Experimental determination of nuclear reaction rates in 238U and 235U along of the radius of fuel pellets of the IPEN/MB-01 reactor

    International Nuclear Information System (INIS)

    Mura, Luis Felipe Liambos

    2015-01-01

    This research presents and consolidates an alternative methodology for determining nuclear reaction rates along the radial direction of the fuel pellets which does not require high neutron flux. This technique is based on irradiating a thin UO 2 disk inserted into a removable fuel rod at the IPEN/MB-01 reactor core. Several gamma spectrometry are performed after irradiation using a HPGe detector. Six lead collimators with different diameters are sequentially alternated during this process, thus, the nuclear radioactive capture which occurs in 238 U and the fissions which occur in both 235 U and 238 U are measured according to six different radial regions of the fuel disk. Geometric efficiency corrections due to the introduction of collimators in HPGe detection system are determined by MCNP-5 code. The fission rate measurements are performed using the 99 Mo. This radionuclide was studied and proved ideal for these measurements because it is formed in linear behavior in the reactor core, have a high yield fission and emits low-energy photons. Measurements were performed irradiating UO 2 disks (with 4.3% enrichment) in the central position of the IPEN/MB-01 core at 100 watts power level during one hour. Some measurements were performed using a cadmium glove wrapped in the fuel rod to determine the nuclear reaction rates in the epithermal energy range. The experimental results obtained are compared with nuclear reaction rate calculations by means of MCNP-5 with ENDF/B-VII.0 data library showing discrepancies of up to 9% in 238 U capture rates and 14% for U fission rates for epithermal energies. Uncertainties regarding the nuclear capture rates have maximum values of 4.5% and the fission rates has maximum values of 11.3%. (author)

  13. Study on the radioactivity and soil-to-plant transfer factor of 226Ra, 234U and 238U radionuclides in irrigated farms from the northwestern Saudi Arabia

    International Nuclear Information System (INIS)

    Al-Hamarneh, Ibrahim F.; Alkhomashi, N.; Almasoud, Fahad I.

    2016-01-01

    The present study addresses the soil-to-plant transfer factors (TFs) of 226 Ra, 234 U and 238 U for 13 types of vegetables and agricultural crops planted under semi-arid environment in the northwestern part of Saudi Arabia. Crop plants along with plant-growing soils were collected from selected farms, which are irrigated from the non-renewable Saq aquifer, and investigated for their radioactivity content by means of alpha spectrometry after applying a radiochemical separation procedure. Hence, TF data for plant roots, green parts (stem and leaves) and fruits were calculated and contrasted to those reported in the literature. Substantial differences were observed in the TFs of Ra and U radioisotopes among plant species. In crop fruits, eggplant exhibited the highest uptake of 226 Ra (TF value of 0.11), while beans (0.16) have the highest TF for 234 U and 238 U. The geometric mean TF values indicated that the crop roots tend to accumulate Ra and U about four to six-folds higher than fruits. The relation between TF values and soil concentrations showed a weak correlation. Activity ratios between radionuclides in crop plants indicated the preferential translocation of U in fruits than Ra even though Ra is more available for root uptake. The fruit/root (F/R) ratios obtained for the investigated plants shown that pepper had the smallest F/R ratios (0.07 ± 0.01, 0.12 ± 0.02 and 0.11 ± 0.02 for 226 Ra, 234 U and 238 U, respectively), while the highest F/R ratios were observed in potatoes (0.71 ± 0.15, 0.44 ± 0.10 and 0.40 ± 0.08 for 226 Ra, 234 U and 238 U, respectively). The TF and F/R ratios data of natural radionuclides in the study region can hopefully improve the scientific knowledge for future studies. - Highlights: • Ra and U isotopes were measured in soils and plant crops in farms in Saudi Arabia. • Ra and U activities in plant roots (R) slightly exceeded that in their fruits (F). • Ra/U activity ratios showed preferential translocation of U

  14. Uranium contents and {sup 235}U/{sup 238}U atom ratios in soil and earthworms in western Kosovo after the 1999 war

    Energy Technology Data Exchange (ETDEWEB)

    Di Lella, L.A.; Nannoni, F.; Protano, G.; Riccobono, F. [Dipartimento di Scienze Ambientali ' G. Sarfatti' -Sezione di Geochimica Ambientale, University of Siena, Via del Laterino 8, I-53100, Siena (Italy)

    2005-01-20

    The uranium content and {sup 235}U/{sup 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 {sup 235}U/{sup 238}U ratio of topsoils showed great variability and were inversely correlated. The highest uranium levels (up to 31.47 mg kg{sup -1}) and lowest {sup 235}U/{sup 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{sup -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 {sup 235}U/{sup 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

  15. Neutron induced 238U subthreshold fission cross section for neutron energies between 5 eV and 3.5 MeV

    International Nuclear Information System (INIS)

    Perez, R.B.; Difilippo, F.C.; Saussure, G. de; Ingle, R.W.

    1978-01-01

    A measurement of the 238 U fission cross section between 5 eV and 3.5 MeV was performed. Included is the identification of 85 resonances or clusters of resonances below 200 keV. Also the fission widths for the 27 resolved class I levels were computed from their fission areas, and a neutron width of 0.005 MeV was estimated for the quasi-class II level in the 721 eV fission cluster. The fission level spacing and cross sections are discussed. 9 references

  16. Evaluation of fission cross sections and covariances for {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Toshihiko [Kyushu Univ., Fukuoka (Japan); Matsunobu, Hiroyuki [Data Engineering, Inc. (Japan); Murata, Toru [AITEL Corporation, Tokyo (JP)] [and others

    2000-02-01

    A simultaneous evaluation code SOK (Simultaneous evaluation on KALMAN) has been developed, which is a least-squares fitting program to absolute and relative measurements. The SOK code was employed to evaluate the fission cross sections of {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu for the evaluated nuclear data library JENDL-3.3. Procedures of the simultaneous evaluation and the experimental database of the fission cross sections are described. The fission cross sections obtained were compared with evaluated values given in JENDL-3.2 and ENDF/B-VI. (author)

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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. - Highlights: → This is a contribution to the knowledge of the Iraqi environment after Gulf War II. → In

  18. Evaluation of fission cross sections and covariances for 233U, 235U, 238U, 239Pu, 240Pu, and 241Pu

    International Nuclear Information System (INIS)

    Kawano, Toshihiko; Matsunobu, Hiroyuki; Murata, Toru

    2000-02-01

    A simultaneous evaluation code SOK (Simultaneous evaluation on KALMAN) has been developed, which is a least-squares fitting program to absolute and relative measurements. The SOK code was employed to evaluate the fission cross sections of 233 U, 235 U, 238 U, 239 Pu, 240 Pu, and 241 Pu for the evaluated nuclear data library JENDL-3.3. Procedures of the simultaneous evaluation and the experimental database of the fission cross sections are described. The fission cross sections obtained were compared with evaluated values given in JENDL-3.2 and ENDF/B-VI. (author)

  19. Identification of more than a 100 new isotopes from 238U projectile fission and beams of neutron-rich nuclei at BRENDA

    International Nuclear Information System (INIS)

    Bernas, M.; Donzaud, C.; Dessagne, Ph.

    1996-01-01

    Projectile fission of 238 U was investigated at a bombarding energy of 750 A MeV using Pb and Be targets. The fully stripped forward emitted fragments from Ti to Cs were analyzed with the Fragment Separator (FRS) and unambiguously identified by their energy-loss and time-of-flight. The magnetic selection of the largest momenta acted as a trigger of the low-energy fission component. More than a hundred new nuclear species were identified including the 78 Ni, for which a cross-section of 300 pb was measured. (author)

  20. Speciation analysis of 129I, 137Cs, 232Th, 238U, 239Pu and 240Pu in environmental soil and sediment

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hansen, Violeta; Hou, Xiaolin

    2012-01-01

    The environmental mobility and bioavailability of radionuclides are related to their physicochemical forms, namely species. We here present a speciation analysis of important radionuclides including 129I (also 127I), 137Cs, 232Th, 238U and plutonium isotopes (239Pu and 240Pu) in soil (IAEA-375......) and sediment (NIST-4354) standard reference materials and two fresh sediment samples from Øvre Heimdalsvatnet Lake, Norway. A modified sequential extraction protocol was used for the speciation analysis of these samples to obtain fractionation information of target radionuclides. Analytical results reveal...

  1. EXCALIBUR-at-CALIBAN: a neutron transmission experiment for {sup 238}U(n,n'{sub continuum}γ) nuclear data validation

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, David; Leconte, Pierre; Destouches, Christophe [CEA, DEN, DER, SPRC et SPEX, Cadarache F-13108 SAINT-PAUL-LEZ-DURANCE (France); Casoli, Pierre; Chambru, Laurent; Chanussot, Didier; Chateauvieux, Herve; Gevrey, Gaetan; Guilbert, Frederique; Lereuil, Hugues; Rousseau, Guillaume; Schaub, Muriel [CEA, DAM, Valduc F-21120 IS-SUR-TILLE (France); Heusch, Murielle; Meplan, Olivier; Ramdhane, Mourad [CNRS/IN2P3, 53 rue des Martyrs, F-38026 Grenoble, Cedex (France)

    2015-07-01

    Two recent papers justified a new experimental program to give a new basis for the validation of {sup 238}U nuclear data, namely neutron induced inelastic scattering and transport codes at neutron fission energies. The general idea is to perform a neutron transmission experiment through natural uranium material. As shown by Hans Bethe, neutron transmissions measured by dosimetric responses are linked to inelastic cross sections. This paper describes the principle and the results of such an experience called EXCALIBUR performed recently (January and October 2014) at the CALIBAN reactor facility. (authors)

  2. Violence of heavy-ion reactions from neutron multiplicity: 11 to 20A MeV /sup 20/Ne+ /sup 238/U

    International Nuclear Information System (INIS)

    Jahnke, U.; Ingold, G.; Hilscher, D.; Lehmann, M.; Schwinn, E.; Zank, P.

    1986-01-01

    The suitability of the neutron multiplicity as a gauge for the violence of medium-energy heavy-ion reactions is investigated for the first time. For this purpose the number of neutrons emitted from fission reactions induced by 220-, 290-, and 400-MeV /sup 20/Ne on /sup 238/U is registered event-by-event with a large 4π scintillator tank. It is shown that the neutron multiplicity is indeed closely related to the two quantities characterizing the violence: the induced total intrinsic excitation and the linear momentum transfer

  3. Measurements of the effective range of fission fragments in UO2 and the disintegration constant for spontaneous fission of 238U

    International Nuclear Information System (INIS)

    Spaggiari, E.R.V.

    1978-01-01

    The results of measuments of the disintegration constant for spontaneous fission in 238 U are presented, with a discussion on the method used for the detection of fission tracks in muscovite mica. Samples of muscovite mica sandwiched between two natural uranium dioxide cylinders were irradiated with fragments of spontaneous fission and the etched tracks counted with projetion optical microscope. The effective thickness of the UO 2 layer which contributed to the observed tracks was measured through irradiation of mica samples, in contact with the UO 2 cylinder with 14,0 MeV neutrons from a (d,t) reaction. (Author) [pt

  4. Daily ingestion of 232Th, 238U, 226Ra, 228Ra and 210Pb in vegetables by inhabitants of Rio de Janeiro City

    International Nuclear Information System (INIS)

    Santos, E.E.; Lauria, D.C.; Amaral, E.C.S.; Rochedo, E.R.

    2002-01-01

    The concentrations of the naturally occurring radionuclides 232 Th, 238 U, 210 Pb, 226 Ra and 228 Ra were determined in the vegetables (leafy vegetables, fruit, root, bean and rice) and derived products (sugar, coffee, manioc flour, wheat flour, corn flour and pasta) consumed most by the adult inhabitants of Rio de Janeiro City. A total of 88 samples from 26 different vegetables and derived products were analyzed. The highest contribution to radionuclide intake arises from bean, wheat flour, manioc flour, carrot, rice, tomato and potato consumption. The estimated daily intakes due to the consumption of vegetables and derived products are 1.9 mBq of 232 Th (0.47 μg), 2.0 mBq of 238 U (0.17 μg), 19 mBq of 226 Ra, 26 mBq of 210 Pb and 47 mBq of 228 Ra. The estimated annual effective dose due to the ingestion of vegetables and their derived products with the long-lived natural radionuclides is 14.5 μSv. Taking into account literature data for water and milk from Rio de Janeiro the dose value increases to 29 μSv, with vegetables and derived products responsible for 50% of the dose and water for 48%. 210 Pb (62%) and 228 Ra (24%) were found to be the main sources for internal irradiation

  5. Neutron induced fission cross sections for /sup 232/Th, /sup 235,238/U, /sup 237/Np and /sup 239/Pu from 1 to 400 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Lisowski, P.W.; Ullmann, J.L.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

    1988-01-01

    Neutron-induced fission cross section ratios for samples of /sup 232/Th, /sup 235,238/U, /sup 237/Np and /sup 239/Pu have been measured from 1 to 400 MeV. The fission reaction rate was determined for all samples simultaneously using a fast parallel plate ionization chamber at a 20-m flight path. A well characterized annular proton recoil telescope was used to measure the neutron fluence up to 30 MeV. These data provided the shape of the /sup 235/U(n,f) cross section relative to the hydrogen scattering cross section. That shape was then normalized to the very accurately known values were determined using the neutron fluence measured with a second proton recoil telescope. Cross section values for /sup 232/Th, /sup 238/U, /sup 237/Np, and /sup 239/Pu were computed from the ratio data using our values for /sup 235/U(n,f). In addition to providing new results at high neutron energies, these data resolve long standing discrepancies among different data sets. 1 ref., 1 fig.

  6. Accurate 238U(n , 2 n )237U reaction cross-section measurements from 6.5 to 14.8 MeV

    Science.gov (United States)

    Krishichayan, Bhike, M.; Tornow, W.; Tonchev, A. P.; Kawano, T.

    2017-10-01

    The cross section for the 238U(n ,2 n )237U reaction has been measured in the incident neutron energy range from 6.5 to 14.8 MeV in small energy steps using an activation technique. Monoenergetic neutron beams were produced via the 2H(d ,n )3He and 3H(d ,n )4He reactions. 238U targets were activated along with Au and Al monitor foils to determine the incident neutron flux. The activity of the reaction products was measured in TUNL's low-background counting facility using high-resolution γ -ray spectroscopy. The results are compared with previous measurements and latest data evaluations. Statistical-model calculations, based on the Hauser-Feshbach formalism, have been carried out using the CoH3 code and are compared with the experimental results. The present self-consistent and high-quality data are important for stockpile stewardship and nuclear forensic purposes as well as for the design and operation of fast reactors.

  7. Seasonal variations of total {sup 234}Th and dissolved {sup 238}U concentration activities in surface water of Bransfield Strait, Antarctica, from March to October 2011

    Energy Technology Data Exchange (ETDEWEB)

    Lapa, Flavia V.; Oliveira, Joselene de; Costa, Alice M.R., E-mail: fvlapa@ipen.br, E-mail: jolivei@ipen.br, E-mail: lice_mrc@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil). Laboratorio de Radiometria Ambiental; Braga, Elisabete S., E-mail: edsbraga@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos

    2013-07-01

    In this study the naturally occurring radionuclides {sup 234}Th and {sup 238}U were used to investigate the magnitude of upper ocean particulate organic carbon export in Bransfield Strait, Southern Ocean. This region is the largest oceanic high-nitrate low-chlorophyll (HNLC) area in the world and is known to contribute to regulate of the atmospheric CO{sub 2} via the biological pump. Due to its different geochemical behavior in seawater, the resulting U/Th disequilibria can be easily used to constrain the transport rates of particles and reaction processes between solution and particulate phases. Sampling occurred during the summer (March and November) 2011. Total {sup 234}Th activities in surface seawater samples ranged from 1.3 to 3.7 dpm L{sup -1} (station EB 011) during March/11 campaign, while in October/11 total {sup 234}Th activity concentrations varied from 1.4 to 2.9 dpm L{sup -1}. Highest total {sup 234}Th activities were found late in the austral summer season. Activity concentrations of dissolved {sup 238}U in surface seawater varied from 2.1 to 2.4 dpm L{sup -1}. Taking into account all sampling stations established in March and October/11 the relative variability of total {sup 234}Th distribution was 22%. (author)

  8. Distribution of radioactive pollution of {sup 238}U, {sup 232}Th, {sup 40}K and {sup 137}Cs in northwestern coasts of Persian Gulf, Iran

    Energy Technology Data Exchange (ETDEWEB)

    Reza Abdi, Mohammad [Department of Physics, University of Isfahan, Isfahan 81747-73441 (Iran, Islamic Republic of)], E-mail: r.abdi@phys.ui.ac.ir; Kamali, Mehdi [Central Laboratory, University of Isfahan, Isfahan 81747-73441 (Iran, Islamic Republic of); Vaezifar, Sedigheh [Department of Chemistry, University of Isfahan, Isfahan 81747-73441 (Iran, Islamic Republic of)

    2008-04-15

    A reconnaissance study has been made of the distribution of {sup 238}U, {sup 232}Th, {sup 40}K and {sup 137}Cs and geochemical features in soils and sediments samples at various locations in the northwestern coast of Persian Gulf. Activity concentration levels due to radionuclides were measured in 30 soil and sediment samples collected from this region. From the measured spectra, activity concentrations were determined for {sup 40}K (range from 146 to 500 Bq kg{sup -1}), {sup 137}Cs (from 5 to 20 Bq kg{sup -1}), {sup 238}U (from 21 to 65 Bq kg{sup -1}) and {sup 232}Th (from 15 to 45 Bq kg{sup -1}) with lowest limit detection (LLD) of 68, 3.2, 4.3 and 4.3 Bq kg{sup -1}, respectively. The dose rate from ambient air at the soil ranges was between 19 and 58 nGy h{sup -1} with an average of 37.41 {+-} 9.66 nGy h{sup -1}.

  9. Potential human health risk by 234,238U and 210Po due to consumption of fish from the "Luis L. Leon" reservoir (Northern Mexico)

    Science.gov (United States)

    Luna-Porres, M. Y.; Rodríguez-Villa, M. A.; Herrera-Peraza, E.; Cabral-Lares, M.; Renteria-Villalobos, M.; Montero-Cabrera, M. E.

    2014-07-01

    The Conchos River is one of the most important in northern Mexico and the main surface waterway in the arid state of Chihuahua. The Luis L. Leon dam produces the Luis L. Leon Reservoir, which is the last major reservoir before the Conchos River enters the Rio Grande at the Texas-Chihuahua border. Activity concentrations (AC) of 234,238U and 210Po in fillet and liver of three stocked fish species (Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus), as well as in water from the Luis L. Leon reservoir were determined. 238U and 234U ACs in fillet samples showed values of 0.007-0.014 and 0.01-0.02 Bq kg-1 wet weight (ww), respectively. Liver samples for Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus species, present 210Po AC of 1.16-3.26 0.70-1.13 and 0.93-1.37 Bqṡkg-1 ww. The elemental Bioaccumulation Factor (BAF) for fish tissues respect to their concentrations in water was determined. Lepomis cyanellus species showed the highest BAF for total uranium in fillet, with value 1.5. The annual effective dose for uranium in adults by fish consumption in this work ranged from 4.46×10-3 to 3.68×10-2 μSvṡyear-1. The difference in concentrations of uranium in fillet among the studied species is likely primarily due to their differences in diet and habitat.

  10. Seasonal variations of total 234Th and dissolved 238U concentration activities in surface water of Bransfield Strait, Antarctica, from March to October 2011

    International Nuclear Information System (INIS)

    Lapa, Flavia V.; Oliveira, Joselene de; Costa, Alice M.R.; Braga, Elisabete S.

    2013-01-01

    In this study the naturally occurring radionuclides 234 Th and 238 U were used to investigate the magnitude of upper ocean particulate organic carbon export in Bransfield Strait, Southern Ocean. This region is the largest oceanic high-nitrate low-chlorophyll (HNLC) area in the world and is known to contribute to regulate of the atmospheric CO 2 via the biological pump. Due to its different geochemical behavior in seawater, the resulting U/Th disequilibria can be easily used to constrain the transport rates of particles and reaction processes between solution and particulate phases. Sampling occurred during the summer (March and November) 2011. Total 234 Th activities in surface seawater samples ranged from 1.3 to 3.7 dpm L -1 (station EB 011) during March/11 campaign, while in October/11 total 234 Th activity concentrations varied from 1.4 to 2.9 dpm L -1 . Highest total 234 Th activities were found late in the austral summer season. Activity concentrations of dissolved 238 U in surface seawater varied from 2.1 to 2.4 dpm L -1 . Taking into account all sampling stations established in March and October/11 the relative variability of total 234 Th distribution was 22%. (author)

  11. Degradation characteristics of waste polyurethane by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Seok; Ahn, Sung Jun; Gwon Hui Jeong; Jeong, Sung In; Nho, Young Chang; Lim, Youn Mook [Research Division for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2017-06-15

    Polyurethane (PU) is a very popular polymer that is used in a variety of applications due to its good mechanical, thermal, and chemical properties. However, waste PU recycling has received significant attention due to environmental issues. The aim of this work was to investigate the degradation characteristics of waste PU to recycle. Degradation of waste PU was carried out using a radiation techniques. Waste PUs were exposed to a gamma {sup 60}Co sources. To verify degradation, the irradiated PUs were characterized using FT-IR, gel permeation chromatography (GPC), and their thermal/mechanical properties are reported. When the radiation dose was 500 kGy, the molecular weight of the waste PU drastically decreased. Also, the mechanical properties of waste PU were approximately 4 times lower than those of non-irradiated PU. This study has confirmed the possibility of making fine particle of waste PU for recycling through radiation degradation techniques.

  12. Contents and daily intakes of gamma-ray emitting nuclides, 90Sr, and 238U using market-basket studies in japan

    International Nuclear Information System (INIS)

    Sugiyama, Hideo; Terada, Hiroshi; Takahashi, Mitsuko; Iijima, Ikuyo; Isomura, Kimio

    2007-01-01

    To investigate the contents of radionuclides in foods marketed in Japan and their daily intakes and exposure doses in adults, we performed market-basket studies concerning radionuclide intakes. The study period was 2003-2005, and the studies were performed in 13 cities in Japan. Foods including drinking water were divided into 14 food groups, and samples were prepared by common cooking procedures. γ-ray emitting nuclides (an artificial radionuclide, radioactive Cs, and natural radionuclides, 40 K and U series such as 214 Bi, and 212 Pb, and Th series) were measured in each food group, and artificial radionuclides, 90 Sr and 238 U, were measured in a mixed sample of 13 food groups excluding drinking water. The daily intakes in adults were calculated from the concentrations of the radionuclides and mean daily consumption of foods and drinking water. The daily 137 Cs and 40 K intakes (mBq/person · day) in the 13 cities were 12.5- 90 Sr intake from the food groups excluding drinking water was 20.8-53.6, with a mean of 39.2 (mBq/person · day) (deviation of the mean: 23%). Similarly, the daily 238 U intake was 5.9-31.1, with a mean of 12.6 (mBq/person · day) (deviation: 60%), showing a more than 5-fold difference between the minimum and maximum values, and there were regional differences. Since the contents of the U series, such as 214 Bi and 212 Pb, and Th series were lower than the lower detection limits in many samples, their daily intakes were not calculated. Regarding the daily intake of 137 Cs from each food group, the intakes from fish and shellfish, milk, meat/eggs, and mushrooms/seaweed tended to be higher. The daily 40 K intake from each food group varied among the areas, but the total intake from the 14 food groups was similar in all 13 cities. 40 K from these foods accounted for most of the annual effective dose (μSv/person · year) of γ-ray emitting nuclides, and the doses of 40 K, 90 Sr, and 238 U were 130-217, 0.21-0.55, and 0.10-0.51, respectively

  13. Cooling Characteristic Analysis of Transformer's Radiator

    International Nuclear Information System (INIS)

    Kim, Hyun Jae; Yang, Si Won; Kim, Won Seok; Kweon, Ki Yeoung; Lee, Min Jea

    2007-01-01

    A transformer is a device that changes the current and voltage by electricity induced between coil and core steel, and it is composed of metals and insulating materials. In the core of the transformer, the thermal load is generated by electric loss and the high temperature can make the break of insulating. So we must cool down the temperature of transformer by external radiators. According to cooling fan's usage, there are two cooling types, OA(Oil Natural Air Natural) and FA(Oil Natural Air Forced). For this study , we used Fluent 6.2 and analyzed the cooling characteristic of radiator. we calculated 1-fin of detail modeling that is similar to honeycomb structure and multi-fin(18-fin) calculation for OA and FA types. For the sensitivity study, we have different positions(side, under) of cooling fans for forced convection of FA type. The calculation results were compared with the measurement data which obtained from 135.45/69kV ultra transformer flowrate and temperature test. The aim of the study is to assess the Fluent code prediction on the radiator calculation and to use the data for optimizing transformer radiator design

  14. A four phases model to simulate the dispersion of 226Ra, 238U and 232Th in an estuary affected by phosphate rock processing

    International Nuclear Information System (INIS)

    Perianez, R.; Abril, J.M.; Garcia-Leon, M.

    1997-01-01

    A numerical model to simulate the dispersion of non conservative radionuclides in tidal waters has been developed. The model includes four phases: water, suspended matter and two grain size sediment fractions. Ionic exchanges between water and the solid phases have been formulated in terms of kinetic transfer coefficients instead of distribution coefficients, because the model was developed for nonequilibrium conditions. The model simultaneously solves the shallow water hydrodynamic equations, the suspended matter dispersion equation and the four equations which give the time evolution of specific activity in each phase. The model has been applied to the Odiel river (southwest Spain), where a phosphate complex releases its wastes. It gives good results in predicting concentrations of 226 Ra, 238 U and 232 Th in water, suspended matter, distribution coefficients and Th/U mass rations. (author)

  15. Evaluation of cross sections for neutron interactions with {sup 238}U in the energy region between 5 keV and 150 keV

    Energy Technology Data Exchange (ETDEWEB)

    Sirakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (Bulgaria); Capote, R.; Trkov, A. [International Atomic Energy Agency, NAPC-Nuclear Data Section, Vienna (Austria); Gritzay, O. [Institute for Nuclear Research, Kyiv (Ukraine); Kim, H.I. [Korea Atomic Energy Research Institute, Nuclear Data Center, Daejeon (Korea, Republic of); Kopecky, S.; Paradela, C.; Schillebeeckx, P. [European Commission, Joint Research Centre, Geel (Belgium); Kos, B. [Jozef Stefan Institute, Ljubljana (Slovenia); Pronyaev, V.G. [Rosatom State Corporation, Atomsrandart, Moscow (Russian Federation)

    2017-10-15

    Cross sections for neutron interactions with {sup 238}U in the energy region from 5 keV to 150 keV have been evaluated. Average total and capture cross sections have been derived from a least squares analysis using experimental data reported in the literature. The resulting cross sections have been parameterised in terms of average resonance parameters maintaining full consistency with results of optical model calculations by using a dispersive coupled channel optical model potential. The average compound partial cross sections have been expressed in terms of transmission coefficients by applying the Hauser-Feshbach statistical reaction theory including width-fluctuations. A generalized single-level representation compatible with the energy-dependent options of the ENDF-6 format has been applied using standard boundary conditions. The results have been transferred into a full ENDF-6 compatible data file. (orig.)

  16. Rare-gas yields in 238U and 232Th fission by 14MeV neutrons, measured by an emanating method

    International Nuclear Information System (INIS)

    Feu Alvim, C.A.; Bocquet, J.P.; Brissot, R.; Crancon, J.; Moussa, A.

    1977-01-01

    A direct method, using emanation of rare gases by uranyle stearate and thorium stearate, has been applied to the measurement of cumulative fractional yields of certain isotopes of krypton and xenon, in the fissions of 238 U and 232 Th by 14MeV-neutrons. The independent yields of the same isotopes were measured previously by means of isotopic on-line separation. From these results, the widths of the mass and charge distributions, the relative chain yields, the fractional cumulative yields of certain bromine and iodine isotopes, the values of Zsub(p) the most probable charge, in the isobaric chains 87-93 and 137-142, and the elemental yields of krypton and xenon were calculated [fr

  17. Neutron induced fission cross section ratios for 232Th, 235,238U, 237Np and 239Pu from 1 to 400 MeV

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Ullmann, J.L.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

    1988-01-01

    Time-of-flight measurements of neutron induced fission cross section ratios for 232 Th, 235,238 U, 237 Np, and 239 Pu, were performed using the WNR high intensity spallation neutron source located at Los Alamos National Laboratory. A multiple-plate gas ionization chamber located at a 20-m flight path was used to simultaneously measure the fission rate for all samples over the energy range from 1 to 400 MeV. Because the measurements were made with nearly identical neutron fluxes, we were able to cancel many systematic uncertainties present in previous measurements. This allows us to resolve discrepancies among different data sets. In addition, these are the first neutron-induced fission cross section values for most of the nuclei at energies above 30 MeV. (author)

  18. Neutron induced fission cross section ratios for 232Th, /sup 235,238/U, 237Np, and 239Pu from 1 to 400 MeV

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Ullmann, J.L.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

    1988-01-01

    Time-of-flight measurements of neutron induced fission cross section ratios for 232 Th, /sup 235,238/U, 237 Np, and 239 Pu, were performed using the WNR high intensity spallation neutron source located at Los Alamos National Laboratory. A multiple-plate gas ionization chamber located at a 20-m flight path was used to simultaneously measure the fission rate for all samples over the energy range from 1 to 400 MeV. Because the measurements were made with nearly identical neutron fluxes, we were able to cancel many systematic uncertainties present in previous measurements. This allows us to resolve discrepancies among different data sets. In addition, these are the first neutron-induced fission cross section values for most of the nuclei at energies above 30 MeV. 8 refs., 3 figs

  19. Determination of 233U, 235U, 238U and 239Pu fission yields induced by fission and 14.7 MeV neutrons

    International Nuclear Information System (INIS)

    Laurec, Jean; Adam, Albert; Bruyne, Thierry de.

    1981-12-01

    The 233 U, 235 U, 238 U, 239 Pu fission yields have been determined by a radiochemical method. A target and a fission chamber made of same fissible material are irradied together. The total fission number is measured from the fission chamber. The fission product activities are directly measured on the target using calibrated Ge-Li detectors. The fissible material masses are determined by alpha and mass spectrometries. The irradiations were made on the critical assemblies PROSPERO and CALIBAN and on the 14 MeV neutron generator of C.E. VALDUC. 3 to 5% fission yield errors are got for the most measured nuclides: 95 Zr, 97 Zr, 99 Mo, 103 Ru, 131 I, 132 Te, 140 Ba, 141 Ce, 143 Ce, 144 Ce, 147 Nd [fr

  20. Ground water contamination with (238)U, (234)U, (235)U, (226)Ra and (210)Pb from past uranium mining: cove wash, Arizona.

    Science.gov (United States)

    Dias da Cunha, Kenya Moore; Henderson, Helenes; Thomson, Bruce M; Hecht, Adam A

    2014-06-01

    The objectives of the study are to present a critical review of the (238)U, (234)U, (235)U, (226)Ra and (210)Pb levels in water samples from the EPA studies (U.S. EPA in Abandoned uranium mines and the Navajo Nation: Red Valley chapter screening assessment report. Region 9 Superfund Program, San Francisco, 2004, Abandoned uranium mines and the Navajo Nation: Northern aum region screening assessment report. Region 9 Superfund Program, San Francisco, 2006, Health and environmental impacts of uranium contamination, 5-year plan. Region 9 Superfund Program, San Franciso, 2008) and the dose assessment for the population due to ingestion of water containing (238)U and (234)U. The water quality data were taken from Sect. "Data analysis" of the published report, titled Abandoned Uranium Mines Project Arizona, New Mexico, Utah-Navajo Lands 1994-2000, Project Atlas. Total uranium concentration was above the maximum concentration level for drinking water (7.410-1 Bq/L) in 19 % of the water samples, while (238)U and (234)U concentrations were above in 14 and 17 % of the water samples, respectively. (226)Ra and (210)Pb concentrations in water samples were in the range of 3.7 × 10(-1) to 5.55 × 102 Bq/L and 1.11 to 4.33 × 102 Bq/L, respectively. For only two samples, the (226)Ra concentrations exceeded the MCL for total Ra for drinking water (0.185 Bq/L). However, the (210)Pb/(226)Ra ratios varied from 0.11 to 47.00, and ratios above 1.00 were observed in 71 % of the samples. Secular equilibrium of the natural uranium series was not observed in the data record for most of the water samples. Moreover, the (235)U/(total)U mass ratios ranged from 0.06 to 5.9 %, and the natural mass ratio of (235)U to (total)U (0.72 %) was observed in only 16 % of the water samples, ratios above or below the natural ratio could not be explained based on data reported by U.S. EPA. In addition, statistical evaluations showed no correlations among the distribution of the radionuclide concentrations

  1. High-precision measurement of the 238U(n,γ) cross-section at the n-TOF facility, CERN

    International Nuclear Information System (INIS)

    Wright, Tobias James; Billowes, Jon; Mingrone, Federica; Massimi, Cristian; Berthoumieux, Eric; Gunsing, Frank; Cano-Ott, Daniel; Mendoza, Emilio; Guerrero, Carlos; Schillebeeckx, P.

    2014-01-01

    A new experiment to measure the 238 U(n,γ) cross-section has been carried out at the CERN n-TOF facility within the ANDES project. Two complementary detection systems have been used: two low neutron sensitivity C6D6 detectors and the Total Absorption Calorimeter (TAC) comprising 40 BaF 2 scintillators. High quality data has been obtained up to 10 keV with the TAC and up to a higher neutron energy unresolved region with the C 6 D 6 . All the steps in the measurements and the subsequent data analysis are dealt with in depth, aiming for overall 2-3% accuracy per detection system. (authors)

  2. Study of deep inelastic collisions in the heavy-ion interaction of (14.0MeV/u){sup 208}Pb+{sup 238}U

    Energy Technology Data Exchange (ETDEWEB)

    Baluch, J J [Department of Physics, Gomal University, D. I. Khan (Pakistan); Khan, E U [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan); Tahseen, R [Department of Physics, Gomal University, D. I. Khan (Pakistan); Qureshi, I E [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan); Nasir, Tabassum [Department of Physics, Gomal University, D. I. Khan (Pakistan); Hassan, Najam ul [Department of Physics, Gomal University, D. I. Khan (Pakistan)

    2006-02-15

    Using mica as a passive detector and employing the 2{pi}-geometry technique (14.0MeV/u) {sup 208}Pb+{sup 238}U heavy-ion nuclear interaction has been studied. The particle tracks were converted into their actual lengths and polar angles through simple geometry. The elastic binary events so bifurcated were used to deduce the coefficients to analyze the three prong events. The relative velocities of the correlated fission fragments were calculated at the second stage of the reaction in order to construct the intermediate stage of the reaction, and hence, determine the pre-fission masses integrated over all angles and energies. The angular distribution of fission fragments within the reaction plane provided the information about the speed of the reaction and proximity effect.

  3. Study of deep inelastic collisions in the heavy-ion interaction of (14.0MeV/u)208Pb+238U

    International Nuclear Information System (INIS)

    Baluch, J.J.; Khan, E.U.; Tahseen, R.; Qureshi, I.E.; Nasir, Tabassum; Hassan, Najam ul

    2006-01-01

    Using mica as a passive detector and employing the 2π-geometry technique (14.0MeV/u) 208 Pb+ 238 U heavy-ion nuclear interaction has been studied. The particle tracks were converted into their actual lengths and polar angles through simple geometry. The elastic binary events so bifurcated were used to deduce the coefficients to analyze the three prong events. The relative velocities of the correlated fission fragments were calculated at the second stage of the reaction in order to construct the intermediate stage of the reaction, and hence, determine the pre-fission masses integrated over all angles and energies. The angular distribution of fission fragments within the reaction plane provided the information about the speed of the reaction and proximity effect

  4. Fission Product Yields of 233U, 235U, 238U and 239Pu in Fields of Thermal Neutrons, Fission Neutrons and 14.7-MeV Neutrons

    Science.gov (United States)

    Laurec, J.; Adam, A.; de Bruyne, T.; Bauge, E.; Granier, T.; Aupiais, J.; Bersillon, O.; Le Petit, G.; Authier, N.; Casoli, P.

    2010-12-01

    The yields of more than fifteen fission products have been carefully measured using radiochemical techniques, for 235U(n,f), 239Pu(n,f) in a thermal spectrum, for 233U(n,f), 235U(n,f), and 239Pu(n,f) reactions in a fission neutron spectrum, and for 233U(n,f), 235U(n,f), 238U(n,f), and 239Pu(n,f) for 14.7 MeV monoenergetic neutrons. Irradiations were performed at the EL3 reactor, at the Caliban and Prospero critical assemblies, and at the Lancelot electrostatic accelerator in CEA-Valduc. Fissions were counted in thin deposits using fission ionization chambers. The number of fission products of each species were measured by gamma spectrometry of co-located thick deposits.

  5. Absolute and relative cross section measurements of 237Np(n,f and 238U(n,f at the National Physical Laboratory

    Directory of Open Access Journals (Sweden)

    Salvador-Castiñeira Paula

    2017-01-01

    Full Text Available Cross section measurements in the fast energy region are being demanded as one of the key ingredients for modelling Generation-IV nuclear power plants. However, in facilities where there are no time-of-flight possibilities or it is not convenient to use them, using the 235U(n,f cross section as a benchmark would require a careful knowledge of the room scatter in the experimental area. In this paper we present measurements of two threshold reactions, 238U(n,f and 237Np(n,f, that could become a standard between their fission threshold and 2.5 MeV, if the discrepancies shown in the evaluations and in some experimental data can be solved. The preliminary results are in agreement with the present ENDF/B-VII.1 evaluation.

  6. Investigation of the fission fragment properties of the reaction 238U(N,F) at incident neutron energies up to 5.8 MeV

    International Nuclear Information System (INIS)

    Vives, F.

    1998-01-01

    The 238 U(n,f) reaction has been studied at various incident neutrons energies from 1,2 at 5,8 MeV. The author shows that the vibrational resonances presence in the cross section threshold area and the protons parity effect, lead to variations in the fission fragments properties. The mass, the total kinetic energy (TKE) and the fragments angular distribution have been obtained thanks a ionisation double chamber use. Mass function changes in the mass and kinetic energy distributions and their respectively contributions to the TKE variations, have also been studied. The two-dimension distributions adjustments mass-TKE have been compared to the theoretical calculus, compiled with the multi-modal random neck-rupture model: two solutions are possible. Meanwhile, only one leads to significant physical interpretation in terms of layers effects. (A.L.B.)

  7. The influence of the nature of soil and plant and pollution on the 238U, 232Th, 222Rn and 220Rn concentrations in various natural honey samples using nuclear track detectors: impact on the adult consumers

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Mortassim, A.

    2009-01-01

    238 U and 232 Th concentrations as well as 222 Rn and 220 Rn α-activities per unit volume were measured in various natural honey samples collected from different regions in Morocco using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). These radionuclides were also measured in soils, plant flowers and nectar solutions corresponding to the honey samples studied. In addition, these radionuclides were measured in different imported honey samples. The measured 238 U, 232 Th, 222 Rn and 220 Rn concentrations ranged from (1.5 ± 0.1) mBq kg -1 to (10.6 ± 0.6) mBq kg -1 , (1.1 ± 0.1) mBq kg -1 to (4.2 ± 0.2) mBq kg -1 , (1.5 ± 0.1) Bq kg -1 to (10.6 ± 0.6) Bq kg -1 and (1.1 ± 0.1) Bq kg -1 to (4.2 ± 0.2) Bq kg -1 for the honey samples studied, respectively. Annual 238 U, 232 Th and 222 Rn intakes by Moroccan adults from the consumption of honey were assessed. The influence of the nature of soil and plant on the 238 U and 232 Th contents of the studied honey samples was investigated. These measurements were completed by an investigation of the 238 U and 232 Th transfer between soils and plant flowers and that between plant flowers and honey, and also by the investigation of the influence of pollution due to different material dusts on 238 U, 232 Th and 222 Rn in the honey samples studied. Committed equivalent doses due to the annual intake of 238 U, 232 Th and 222 Rn were evaluated in the organs of adult members of the Moroccan rural population from the ingestion of the honey samples. The maximum total committed effective dose due to 238 U, 232 Th and 222 Rn from the ingestion of natural honey by the Moroccan rural population was found to be equal to 0.64 μSνy -1 . (author)

  8. Radiative characteristics of CVL pumped dye laser

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Uichi; Ishiguro, Takahide

    1987-09-01

    This paper describes the radiative characteristics of CVL pumped dye laser. It is compared YAG-SH (530 nm) with CVL (511, 578 nm) and CVL (511 nm) for pumping source. Influence of solvent in dye laser power was examined. The present experimental results show that efficiency of CVL (511 nm) pumped dye laser was most high. When the dye solution is at a standstill, the efficiency of dye laser with water and Sodium Lauryl Sulfate (S.L.S., 2 %wt.) was most high among the four kinds of solvent. In the condition of dye solution flow, the water and S.L.S. or ethylene glycol was useful solvent for dye laser.

  9. Radiative characteristics of CVL pumped dye laser

    International Nuclear Information System (INIS)

    Kubo, Uichi; Ishiguro, Takahide.

    1987-01-01

    This paper describes the radiative characteristics of CVL pumped dye laser. It is compared YAG-SH (530 nm) with CVL (511, 578 nm) and CVL (511 nm) for pumping source. Influence of solvent in dye laser power was examined. The present experimental results show that efficiency of CVL (511 nm) pumped dye laser was most high. When the dye solution is at a standstill, the efficiency of dye laser with water and Sodium Lauryl Sulfate (S.L.S., 2 %wt.) was most high among the four kinds of solvent. In the condition of dye solution flow, the water and S.L.S. or Ethylene Glycol was useful solvent for dye laser. (author)

  10. Production and desexcitation of hot nuclei in 40Ar + 238U collisions at 27 MeV/u

    International Nuclear Information System (INIS)

    Jacquet, D.

    1987-01-01

    The selection of hot nuclei can be achieved through the folding angle of the coincident fission fragments. At this bombarding energy a distinct fusion component shows up in the folding angle correlation function corresponding to the most central collisions. The mass of the fission fragments decreases with increasing linear momentum transfer; the energy dissipated into the target nucleus is proportional to the momentum transfer. The mass distribution full width at half maximum increases with dissipated energy and this can be understood as the result of thermal fluctuations. The light charged particles detected in coincidence with the fission fragments exhibit, at least backwards, the characteristic behaviour of evaporative particles from a thermally equilibrated source. The fused nucleus is revealed as the dominant emitter. The observed energy spectra can be reproduced in a Monte Carlo type simulation assuming that about 80% of the particles arise from the fused nuclei and only 20 % from the fully accelerated fission fragments. A detailed analysis of the shape of the spectra allows to precise the average characteristics of the emitter: it is quite deformed has a very broad spin distribution and a temperature from 4 to 5 MeV. All these characteristics are consistently deduced in semi-classical dynamical calculations based on the Landau-Vlasov equation. The pre-fission particle emission probabilities are shown to be much larger than would predict a purely statistical model for such heavy and hot nuclei. Such a behaviour can only be understood if the dynamics of the collision is taken into account [fr

  11. Origin and geochemical behavior of uranium in marine sediments. Utilization of the 234U/238U ratio in marine geochemistry

    International Nuclear Information System (INIS)

    Organo, Catherine

    1997-01-01

    The first part of this thesis presents the current situation of knowledge of uranium in marine environment. The second part describes the methods of analysis as well as the material support of the study, i.e., the sediments and marine deposits investigated. The third part is dedicated to the study of uranium mobility in marine sediments characterized by detrital terrigenous composition (pelagic clays). This approach allowed quantifying the entering and leaving flux of uranium after the sediment settling and, to discuss, on this basis, the consequences on the uranium oceanic balance. In the third part the origin and behavior of uranium in zones of high surface productivity is studied. The uranium enrichments observed in the hemi-pelagic sediments of the EUMELI (J.G.O.F.S.-France) programme will constitute a material of study adequate for measuring the variations in the 234 U/2 38U ratio in solid phase, in response to the oxido-reducing characteristics of the sediment. Thus establishing the origin of the trapped uranium has been possible. Also, the nature of the sedimentary phases related to uranium in bio-genetic sediments in the Austral Ocean was determined. Thus a relationship between the variations in the 234 U/ 238 and the diagenetic transformations was possible to establish. Finally in the fifth part a study of the behavior of uranium in a polymetallic shell characteristic for deposits of hydrogenized origin

  12. Uranium isotopic ratio measurements ({sup 235}U/{sup 238}U) by laser ablation high resolution inductively coupled plasma mass spectrometry for environmental radioactivity monitoring - {sup 235}U/{sup 238}U isotope ratio analysis by LA-ICP-MS-HR for environmental radioactivity monitoring

    Energy Technology Data Exchange (ETDEWEB)

    David, K.; Mokili, M.B.; Rousseau, G.; Deniau, I.; Landesman, C. [SUBATECH, Ecole des Mines de Nantes, Universite de Nantes, CNRS/IN2P3, 4 rue Alfred Kastler, 44307 Nantes cedex 3 (France)

    2014-07-01

    The protection of the aquatic and terrestrial environments from a broad range of contaminants spread by nuclear activities (nuclear plants, weapon tests or mining) require continuous monitoring of long-lives radionuclides that were released into the environment. The precise determination of uranium isotope ratios in both natural and potential contaminated samples is of primary concern for the nuclear safeguards and the control of environmental contamination. As an example, analysis of environmental samples around nuclear plants are carried out to detect the traces in the environment originating from nuclear technology activities. This study deals with the direct analysis of {sup 235}U/{sup 238}U isotope ratios in real environmental solid samples performed with laser ablation (LA)-HR-ICP-MS. A similar technique has already been reported for the analysis of biological samples or uranium oxide particles [1,2] but to our knowledge, this was never applied on real environmental samples. The high sensitivity, rapid acquisition time and low detection limits are the main advantages of high resolution ICP-MS for accurate and precise isotope ratio measurements of uranium at trace and ultra-trace levels. In addition, the use of laser ablation allows the analysis of solid samples with minimal preparation. A a consequence, this technique is very attractive for conducting rapid direct {sup 235}U/{sup 238}U isotope ratio analysis on a large set of various matrix samples likely to be encountered in environmental monitoring such as corals, soils, sands, sediments, terrestrial and marine bio-indicators. For the present study, LA-ICP-MS-HR analyses are performed using a New Wave UP213 nano-second Nd:YAG laser coupled to a Thermo Element-XR high resolution mass spectrometer. Powdered samples are compacted with an hydraulic press (5 tons) in order to obtain disk-shaped pellet (10-13 mm in diameter and 2 mm in thickness). The NIST612 reference glass is used for LA-ICP-MS-HR tuning and as

  13. Determination of committed effective doses to skin due to 238U, 232Th and 222Rn from the application of various Moroccan black soap (Saboun Beldi) samples by members of the general public

    International Nuclear Information System (INIS)

    Misdaq, M. A.; Outeqablit, K.

    2010-01-01

    238 U, 232 Th, 222 Rn and 220 Rn concentrations were measured inside various Moroccan black soap samples widely used by the Moroccan population in traditional baths (Hammams) by using both CR-39 and LR-115 type II solid state nuclear track detectors. The measured 238 U, 232 Th, 222 Rn and 220 Rn concentrations, respectively, ranged from (3.7±0.2) to (11.7±0.7) mBq kg -1 , (0.11±0.01) to (0.32±0.02) mBq kg -1 , (3.8±0.2) to (11.6±0.6) Bq kg -1 and (0.10±0.01) to (0.31±0.02) Bq kg -1 for the Moroccan black soap samples studied. The influence of pollution on the concentrations of these radionuclides inside the considered Moroccan black soap was investigated. A new dosimetric model for evaluating annual committed effective doses due to 238 U, 232 Th and 222 Rn to the skin of different age groups of the Moroccan populations from the application of the black soap samples studied was developed. The maximum total committed effective dose to the skin due to 238 U, 232 Th and 222 Rn from the application of unpolluted black soap samples 20 min per week by the Moroccan populations was found to be equal to (0.88±0.05) μSv y -1 cm -2 . (authors)

  14. Determination of natural radionuclides from 238U and 232Th series, trace and major elements in sediment cores from baixada Santista and evaluation of impacted areas

    International Nuclear Information System (INIS)

    Damatto, Sandra Regina

    2010-01-01

    Baixada Santista is the region of higher population of the coast of Sao Paulo State, where it is located the largest port in Latin America, in the city of Santos, and the most important industrial complex of Latin America, in the city of Cubatao. This region has received in recent years a considerable load of industrial and domestic effluents in its water bodies, as a direct result of the industrial and port activities and the large population growth in recent decades, and is considered nowadays highly impacted. In the present study sediment cores were collected in the estuary of Santos-Cubatao, in the estuary of Sao Vicente, in the channel of Bertioga and Santos Bay, in order to determine the concentration of trace and major elements and natural radionuclides from the 238 U and 232 Th series. The techniques used were neutron activation analysis, X-ray fluorescence and gamma spectrometry, respectively. The obtained values for the elements Cr, Sb, Ta and Zn in some cores, are higher than data from literature, and can indicate a possible anthropic contribution. Comparing the obtained values of Cr and Zn elements determined in the sediment cores with the values of TEL and PEL index for sediment quality, it was verified that the studied region presents Cr levels higher than TEL in Santos-Cubatao estuary and Bertioga channel and Zn element presented values higher than TEL for some core slices of Santos-Cubatao estuary, for one core of Sao Vicente estuary, one core in Bertioga channel and Santos Bay. For the other elements, the values obtained in this study can be considered as reference values for the region. Although the element As presented higher values than the TEL in all the studied environments, the concentrations obtained are of the same order of magnitude as literature data and, therefore, can be considered also as reference values for the region. No enrichment was found for the major elements in all the ecosystems studied, with the exception for the element P

  15. Distinct 238U/235U ratios and REE patterns in plutonic and volcanic angrites: Geochronologic implications and evidence for U isotope fractionation during magmatic processes

    Science.gov (United States)

    Tissot, François L. H.; Dauphas, Nicolas; Grove, Timothy L.

    2017-09-01

    Angrites are differentiated meteorites that formed between 4 and 11 Myr after Solar System formation, when several short-lived nuclides (e.g., 26Al-26Mg, 53Mn-53Cr, 182Hf-182W) were still alive. As such, angrites are prime anchors to tie the relative chronology inferred from these short-lived radionuclides to the absolute Pb-Pb clock. The discovery of variable U isotopic composition (at the sub-permil level) calls for a revision of Pb-Pb ages calculated using an ;assumed; constant 238U/235U ratio (i.e., Pb-Pb ages published before 2009-2010). In this paper, we report high-precision U isotope measurement for six angrite samples (NWA 4590, NWA 4801, NWA 6291, Angra dos Reis, D'Orbigny, and Sahara 99555) using multi-collector inductively coupled plasma mass-spectrometry and the IRMM-3636 U double-spike. The age corrections range from -0.17 to -1.20 Myr depending on the samples. After correction, concordance between the revised Pb-Pb and Hf-W and Mn-Cr ages of plutonic and quenched angrites is good, and the initial (53Mn/55Mn)0 ratio in the Early Solar System (ESS) is recalculated as being (7 ± 1) × 10-6 at the formation of the Solar System (the error bar incorporates uncertainty in the absolute age of Calcium, Aluminum-rich inclusions - CAIs). An uncertainty remains as to whether the Al-Mg and Pb-Pb systems agree in large part due to uncertainties in the Pb-Pb age of CAIs. A systematic difference is found in the U isotopic compositions of quenched and plutonic angrites of +0.17‰. A difference is also found between the rare earth element (REE) patterns of these two angrite subgroups. The δ238U values are consistent with fractionation during magmatic evolution of the angrite parent melt. Stable U isotope fractionation due to a change in the coordination environment of U during incorporation into pyroxene could be responsible for such a fractionation. In this context, Pb-Pb ages derived from pyroxenes fraction should be corrected using the U isotope composition

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

    Energy Technology Data Exchange (ETDEWEB)

    Boulyga, Sergei F. [Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14, 55099 Mainz (Germany)]. E-mail: sergei.boulyga@univie.ac.at; Heumann, Klaus G. [Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University Mainz, Duesbergweg 10-14, 55099 Mainz (Germany)

    2006-07-01

    A method by inductively coupled plasma mass spectrometry (Icp-Ms) was developed which allows the measurement of {sup 236}U at concentration ranges down to 3 x 10{sup -14} g g{sup -1} and extremely low {sup 236}U/{sup 238}U isotope ratios in soil samples of 10{sup -7}. By using the high-efficiency solution introduction system APEX in connection with a sector-field ICP-MS a sensitivity of more than 5000 counts fg{sup -1} uranium was achieved. The use of an aerosol desolvating unit reduced the formation rate of uranium hydride ions UH{sup +}/U{sup +} down to a level of 10{sup -6}. An abundance sensitivity of 3 x 10{sup -7} was observed for {sup 236}U/{sup 238}U isotope ratio measurements at mass resolution 4000. The detection limit for {sup 236}U and the lowest detectable {sup 236}U/{sup 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 {sup 236}U/{sup 238}U isotope ratio is a much more sensitive and accurate marker for environmental contamination by spent uranium in comparison to the {sup 235}U/{sup 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 {sup 236}U in the upper 0-10 cm soil layers varied from 2 x 10{sup -9} g g{sup -1} within radioactive spots close to the Chernobyl NPP to 3 x 10{sup -13} g g{sup -1} on a sampling site located by >200 km from Chernobyl.

  17. Geochemical and multi-isotopic (87Sr/86Sr, 143Nd/144Nd, 238U/235U) perspectives of sediment sources, depositional conditions, and diagenesis of the Marcellus Shale, Appalachian Basin, USA

    Science.gov (United States)

    Phan, Thai T.; Gardiner, James B.; Capo, Rosemary C.; Stewart, Brian W.

    2018-02-01

    We investigate sediment sources, depositional conditions and diagenetic processes affecting the Middle Devonian Marcellus Shale in the Appalachian Basin, eastern USA, a major target of natural gas exploration. Multiple proxies, including trace metal contents, rare earth elements (REE), the Sm-Nd and Rb-Sr isotope systems, and U isotopes were applied to whole rock digestions and sequentially extracted fractions of the Marcellus shale and adjacent units from two locations in the Appalachian Basin. The narrow range of εNd values (from -7.8 to -6.4 at 390 Ma) is consistent with derivation of the clastic sedimentary component of the Marcellus Shale from a well-mixed source of fluvial and eolian material of the Grenville orogenic belt, and indicate minimal post-depositional alteration of the Sm-Nd system. While silicate minerals host >80% of the REE in the shale, data from sequentially extracted fractions reflect post-depositional modifications at the mineralogical scale, which is not observed in whole rock REE patterns. Limestone units thought to have formed under open ocean (oxic) conditions have δ238U values and REE patterns consistent with modern seawater. The δ238U values in whole rock shale and authigenic phases are greater than those of modern seawater and the upper crust. The δ238U values of reduced phases (the oxidizable fraction consisting of organics and sulfide minerals) are ∼0.6‰ greater than that of modern seawater. Bulk shale and carbonate cement extracted from the shale have similar δ238U values, and are greater than δ238U values of adjacent limestone units. We suggest these trends are due to the accumulation of chemically and, more likely, biologically reduced U from anoxic to euxinic bottom water as well as the influence of diagenetic reactions between pore fluids and surrounding sediment and organic matter during diagenesis and catagenesis.

  18. Vertical and horizontal distribution of radionuclides ({sup 232}Th, {sup 238}U and {sup 40}K) in sediment from Manjung coastal water area Perak, Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Anisa, E-mail: coppering@ymail.com; Hamzah, Zaini; Wood, Ab. Khalik [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor (Malaysia); Saat, Ahmad [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor (Malaysia); Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2016-01-22

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides ({sup 232}Th, {sup 238}U and {sup 40}K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (I{sub geo}) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (H{sub ex})

  19. Capture and Fission rate of 232-Th, 238-U, 237-Np and 239-Pu from spallation neutrons in a huge block of lead.

    CERN Document Server

    Vlachoudis, Vasilis

    2000-01-01

    The study is centered on the research of the incineration possibility of nuclear waste, by the association of a particle accelerator with a multiplying medium of neutrons, in the project "Energy Amplifier" of C. Rubbia. It consists of the experimental determination of the rates of capture and fission of certain elements (232-Th, 238-U, 237-Np and 239-Pu) subjected to a fluence of fast spallation neutrons. These neutrons are produced by the interaction of high kinetic energy protons (several GeV) provided by the CERN-PS accelerator, on a large lead solid volume. The measurement techniques used in this work, are based on the activation of elements in the lead volume and the subsequent gamma spectroscopy of the activated elements, and also by the detection of fission fragment traces. The development, of a Monte Carlo code makes it possible, on one hand, to better understand the relevant processes, and on the other hand, to validate the code, by comparison with measurements, for the design and the construction of...

  20. Measurements of prompt fission neutron spectra and double-differential neutron inelastic-scattering cross sections for 238U and 232Th

    International Nuclear Information System (INIS)

    Baba, Mamoru; Itoh, Nobuo; Maeda, Kazuto; Hirakawa, Naohiro; Wakabayashi, Hidetaka.

    1989-10-01

    This report presents the summary of experimental studies of prompt fission neutron spectra and double-differential neutron inelastic-scattering cross sections of 238 U and 232 Th. The experiments were performed at Tohoku University Fast Neutron Laboratory employing a time-of-flight technique and Dynamitron accelerator as the pulsed neutron generator. From the experiments, we obtained the following data for both nuclei; 1. prompt fission neutron spectrum for 2 MeV neutrons, 2. double-differential neutron inelastic-scattering cross sections for 1.2, 2.0, 4.2, 6.1 and 14.1 MeV incident neutrons. Both in experiments and data processing, cares were taken to obtain reliable data by avoiding systematic uncertainty. The experimental data were compared with those by other experiments, evaluations and model calculations. Through the data comparison, some fundamental problems were found in the experiments by previous authors and the evaluations. The present data will provide useful data base for refinement of the evaluated data and theoretical models. (author)

  1. Estimation of covariances of 16O, 23Na, Fe, 235U, 238U and 239Pu neutron nuclear data in JENDL-3.2

    International Nuclear Information System (INIS)

    Shibata, Keiichi; Nakajima, Yutaka; Kawano, Toshihiko; Oh, Soo-Youl; Matsunobu, Hiroyuki; Murata, Toru.

    1997-10-01

    Covariances of nuclear data have been estimated for 6 nuclides contained in JENDL-3.2. The nuclides considered are 16 O, 23 Na, Fe, 235 U, 238 U, and 239 Pu, which are regarded as important for the nuclear design study of fast reactors. The physical quantities for which covariances are deduced are cross sections, resolved and unresolved resonance parameters, and the first order Legendre-polynomial coefficient for the angular distribution of elastically scattered neutrons. As for 235 U, covariances were obtained also for the average number of neutrons emitted in fission. The covariances were estimated by using the same methodology that had been used in the JENDL-3.2 evaluation in order to keep a consistency between mean values and their covariances. The least-squares fitting code GMA was used in estimating covariances for reactions of which JENDL-3.2 cross sections had been evaluated by taking account of measurements. In nuclear model calculations, the covariances were calculated by the KALMAN system. The covariance data obtained were compiled in the ENDF-6 format, and will be put into the JENDL-3.2 Covariance File which is one of JENDL special purpose files. (author). 193 refs

  2. Vertical and horizontal distribution of radionuclides (232Th, 238U and 40K) in sediment from Manjung coastal water area Perak, Malaysia

    Science.gov (United States)

    Abdullah, Anisa; Hamzah, Zaini; Saat, Ahmad; Wood, Ab. Khalik

    2016-01-01

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides (232Th, 238U and 40K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (Igeo) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (Hex).

  3. The reaction {sup 48}Ca+{sup 238}U {yields}{sup 286}112{sup *} studied at the GSI-SHIP

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, S. [Gesellschaft fuer Schwerionenforschung (GSI), D-64291 Darmstadt (Germany); Institut fuer Kernphysik, Johann Wolfgang Goethe-Universitaet, Frankfurt (Germany); Ackermann, D.; Burkhard, H.G.; Heinz, S.; Hessberger, F.P.; Khuyagbaatar, J.; Kindler, B.; Kojouharov, I.; Lommel, B.; Mann, R.; Muenzenberg, G.; Schoett, H.J.; Sulignano, B. [Gesellschaft fuer Schwerionenforschung (GSI), Darmstadt (Germany); Antalic, S.; Saro, S.; Streicher, B.; Venhart, M. [Comenius University, Department of Nuclear Physics and Biophysics, Bratislava (Slovakia); Comas, V.F.; Heredia, J.A. [InSTEC, Habana (Cuba); Dressler, R. [Paul Scherrer Institute, Villigen (Switzerland); Gan, Z. [Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Kuusiniemi, P. [University of Oulu, CUPP (Finland); Leino, M.; Uusitalo, J. [University of Jyvaeskylae, Department of Physics, Jyvaeskylae (Finland); Nishio, K. [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan); Popeko, A.G.; Yeremin, A.V. [JINR, Flerov Laboratory of Nuclear Reactions, Dubna (Russian Federation)

    2007-06-15

    The fusion reaction of {sup 48}Ca projectiles with {sup 238}U target nuclei was studied at the velocity filter SHIP of GSI in Darmstadt. Two decay chains were measured, which fully confirm data that were previously assigned to the isotope {sup 283}112 in experiments at the Flerov Laboratory in Dubna. Two other events are consistent with a 50% spontaneous-fission (SF) branch of this isotope. The mean value obtained for the half-life of {sup 283}112 is (6.9{sup +6.9}{sub -2.3}) s, the {alpha} energy is (9.520{+-}0.015) MeV, and the total kinetic energy (TKE) of SF is (238{+-}14) MeV. The half-life of the {alpha} decay daughter nucleus {sup 279}Ds is (0.18{sup +0.32}{sub -0.07}) s, and the TKE of SF is (210 {sup +32}{sub -11}) MeV. The cross-section deduced from all four events is (0.72{sup +0.58}{sub -0.35}) pb, measured at an excitation energy of 34.6MeV of the compound nucleus {sup 286}112. (orig.)

  4. Systematic experimental survey on projectile fragmentation and fission induced in collisions of {sup 238}U at 1 A GeV with lead

    Energy Technology Data Exchange (ETDEWEB)

    Enquist, T.; Benlliure, J.; Farget, F.; Schmidt, K.H.; Armbruster, P. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Bernas, M.; Tassan-Got, L. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Boudard, A.; Legrain, R.; Volant, C. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de Physique des Particules, de Physique Nucleaire et de l`Instrumentation Associee (DAPNIA); Boeckstiegel, C.; Jong, M. de [Technische Univ. Darmstadt (Germany); Dufour, J.P. [CEA Centre d`Etudes Nucleaires de Bordeaux-Gradignan, 33 - Gradignan (France)

    1999-03-01

    Projectile fragmentation and fission, induced in collisions of {sup 238}U at 1 A GeV with lead, have systematically been studied. A complete survey on the isotopic production cross sections of all elements between vanadium (Z = 23) and rhenium (Z = 75) down to a cross section of 0.1 mb is given. About 600 isotopes produced in fragmentation and about 600 isotopes produced in fission were identified in the GSI fragment separator FRS from magnetic rigidities, time-of-flight values, and the energy loss in an ionisation chamber. In addition, the velocity distributions of all these reaction products have been mapped, and the products are unambiguously attributed to the different reaction mechanisms due to their kinematical properties. The results are compared with empirical systematics and previous data. The velocity of the fragments obtained in the fission process by the Coulomb repulsion allows to reconstruct the TKE-value of the break-up and to identify the atomic number of the fissioning nucleus in hot fission. The mean velocities of light projectile fragments were found to be higher than the beam velocity. (orig.) 41 refs.

  5. Elastic scattering of 40Ar and 84Kr on 209Bi and 238U at 7.2 and 8.5 MeV/N

    International Nuclear Information System (INIS)

    Birkelund, J.R.; Huizenga, J.R.; Freiesleben, H.; Wolf, K.L.; Unik, J.P.; Viola, V.E. Jr.

    1976-01-01

    Cross sections for elastic scattering of 40 Ar on targets of 209 Bi and 238 U were measured at energies of 286 and 340 MeV. Cross sections for the elastic scattering of 84 Kr on 209 Bi were measured at energies of 600 and 712 MeV. These experimental elastic scattering data were fitted with optical and Fresnel models. The total reaction cross section deduced from the Fresnel model by the one-quarter point technique agrees within a few percent with the result from the optical model. The Fresnel interaction radius and the optical model strong absorption radius are found to be approximately equal and qualitatively reproduced by the sum of the half-density electron scattering radii of the two heavy ions and a constant of 3.2+-0.3 fm. A method of estimating total reaction cross sections for heavy ions is presented. Some observations on the real and imaginary potentials of very heavy ions are presented

  6. 230Th-238U radioactive disequilibria in tholeiites from the FAMOUS zone (Mid-Atlantic Ridge, 36050'N): Th and Sr isotopic geochemistry

    International Nuclear Information System (INIS)

    Condomines, M.; Morand, P.; Allegre, C.J.

    1981-01-01

    We analyzed, U, Th and 230 Th/ 232 Th activity ratios for a few tholeiites from the Mid-Atlantic Ridge FAMOUS zone at 36 0 50'N. The results show a fairly wider scatter for both Th/U and ( 230 Th/ 232 Th) ratios. Seawater contamination appears to be responsible for this scatter and, for the uranium, produces an increase in content yielding a ( 234 U/ 238 U) ratio greater than 1 and, for the Th, an increase of the ( 230 Th/ 232 Th) ratio which is a very sensitive indicator for contamination. Also, the latter often is selective: U, Th and Sr are not affected in the same manner. When discarding all data for contaminated samples, the FAMOUS zone appears to be very homogeneous with a Th/U ratio value of 3.05 and a ( 230 Th/ 232 Th) ratio value of 1.24. Comparison with other active volcanic areas reveals a negative correlation between ( 230 Th/ 232 Th) and 87 Sr/ 86 Sr ratios for present lavas which is indicative of a consistency in Th-U and Rb-Sr fractionation in the source regions of these magmas. The Th isotopic geochemistry can thus provide useful information for the study of present volcanism, information as valuable as that from Sr, Pb or Nd isotopes. (orig.)

  7. Correlation of the activity of the 238 U in soil and 222 Rn in domiciles, with the rocks of cities of the Estado de Chihuahua

    International Nuclear Information System (INIS)

    Colmenero S, L.; Villalba, L.; Montero C, M.E.

    2004-01-01

    The state of Chihuahua has numerous locations of uranium, being Pena Blanca the great and more important location of the country. Diverse rock types with important quantities of uranium are distributed by the whole state. The igneous extrusive acid rocks are those that have bigger quantity of uranium, like they are the rhyolites and dacites and these rocks are located in enough proportion by the whole state. Some of the main cities of the state are near to locations or uraniferous rocks, as Aldama, Nuevo Casas Grandes, Chihuahua, Jimenez and Bocoyna, other important cities are not near important locations. It was determined specific activity by gamma spectroscopy of the series of the 238 U in soils and determination of the radon concentration in domiciles of the main cities of the state. They were found high specific activity values in soil in eight of the thirteen analyzed cities and important radon concentrations in three cities. It was found relationship among the specific activity in soil in near cities to uraniferous locations. (Author)

  8. Studies of 4He emission in both fusion-like and inelastic reactions of 340-MeV 40Ar + 238U

    International Nuclear Information System (INIS)

    Kildir, M.; Logan, D.; Kaplan, M.; Zisman, M.S.; Guerreau, D.; Alexander, J.M.; Vaz, L.C.

    1982-01-01

    The fission-fragment angular correlation technique has been used in conjunction with a position-sensitive avalanche detector to identify the fusion-like and inelastic collisions of 340-MeV 40 Ar + 238 U. For each of these two reaction types, we have characterized the correlated 4 He emission by measuring three-fold coincidences between two fission fragments and the light charged particle. We find an abundance of both evaporation-like and direct 4 He emission, each of which is associated with both fusion-fission and sequential-fission processes. Several comparison tests of both the coincidence and singles data strongly indicate that very little 4 He emission is due to evaporation from accelerated fission fragments in this system. The evaporative 4 He emission appears instead to have a strong contribution originating from the composite system prior to fission. The forward angle 4 He emissions, characterized by prominent forward-peaking and relatively high energies, suggest an origin associated with the very early stages of the collision

  9. High-resolution tephrochronology of the Wilson Creek Formation (Mono Lake, California) and Laschamp event using 238U-230Th SIMS dating of accessory mineral rims

    Science.gov (United States)

    Vazquez, Jorge A.; Lidzbarski, Marsha I.

    2012-12-01

    Sediments of the Wilson Creek Formation surrounding Mono Lake preserve a high-resolution archive of glacial and pluvial responses along the eastern Sierra Nevada due to late Pleistocene climate change. An absolute chronology for the Wilson Creek stratigraphy is critical for correlating the paleoclimate record to other archives in the western U.S. and the North Atlantic region. However, multiple attempts to date the Wilson Creek stratigraphy using carbonates and tephras yield discordant results due to open-system effects and radiocarbon reservoir uncertainties as well as abundant xenocrysts. New ion microprobe 238U-230Th dating of the final increments of crystallization recorded by allanite and zircon autocrysts from juvenile pyroclasts yield ages that effectively date eruption of key tephra beds and delimit the timing of basal Wilson Creek sedimentation to the interval between 26.8±2.1 and 61.7±1.9 ka. Tephra (Ash 15) erupted during the geomagnetic excursion originally designated the Mono Lake excursion yields an age of 40.8±1.9 ka, indicating that the event is instead the Laschamp excursion. The new ages support a depositional chronology from magnetostratigraphy that indicates quasi-synchronous glacial and hydrologic responses in the Sierra Nevada and Mono Basin to regional climate change, with intervals of lake filling and glacial-snowpack melting that are in phase with peaks in spring insolation.

  10. Investigations of the mass and charge distribution of fission products from the 238U(n14,f) reaction by direct Ge(Li) method

    International Nuclear Information System (INIS)

    Daroczy, S.

    1979-01-01

    The fission yields can be measured by the well-known activation method if it is taken into account that the fission process results in 5-6 nuclides in an isobaric chain. The method which is based only on the gamma-spectrometric measurement of the irradiated fissioning sample is referred to as the direct Ge(Li) method for fission yield measurement. The thesis contains detailed description of the direct Ge(Li) method. The method was tested by the measurement of cumulative yields of 47 fission products and independent yields of 7 products in the reaction of 238 U(n 14 ,f). These are the members of 37 mass chains in the A=83-149 mass number region. The half-lives of the studied products are in the range of Tsub(1/2)=10 2 -10 9 s; the gamma spectrometric method was improved by extending its applicability to the measurement of short-lived products. Applying short irradiation time (5 min) the yields of 16 fission products with half-lives shorter than 1 hour could be measured. The lowest measured partial fission cross sections (yields) are in the order of 1 mb (0.1%). The accuracy of the yield measured by the direct Ge(Li) method is as high as or higher than that obtained radiochemically, especially for the products measured by many intensive gamma lines. (author)

  11. 238U-234U-230Th-232Th systematics and the precise measurement of time over the past 500,000 years

    International Nuclear Information System (INIS)

    Edwards, R.L.; Chen, J.H.; Wasserburg, G.J.

    1987-01-01

    We have developed techniques to measure the 230 Th abundance in corals by isotope dilution mass spectrometry. This, coupled with our previous development of mass spectrometric techniques for 234 U and 232 Th measurement, has allowed us to reduce significantly the analytical errors in 238 U- 234 U- 230 Th dating and greatly reduce the sample size. We show that 6x10 8 atoms of 230 Th can be measured to ±30per mille (2 σ) and 2x10 10 atoms of 230 Th to ±2per mille. The time over which useful age data on corals can be obtained ranges from a few years to ≅ 500 ky. The uncertainty in age, based on analytical errors, is ±5 y(2 σ) for a 180 year old coral (3 g), ±44 y at 8294 years and ±1.1 ky at 123.1 ky (250 mg of coral). We also report 232 Th concentrations in corals (0.083-1.57 pmol/g) that are more than two orders of magnitude lower than previous values. Ages with high analytical precision were determined for several corals that grew during high sea level stands ≅ 120 ky ago. These ages lie specifically within or slightly postdate the Milankovitch insolation high at 128 ky and support the idea that the dominant cause of Pleistocene climate change is Milankovitch forcing. (orig.)

  12. Systematic experimental survey on projectile fragmentation and fission induced in collisions of 238U at 1 A GeV with lead

    International Nuclear Information System (INIS)

    Enqvist, T.; Benlliure, J.; Farget, F.; Schmidt, K.H.; Armbruster, P.; Bernas, M.; Tassan-Got, L.; Boeckstiegel, C.; Jong, M. de; Dufour, J.P.

    1999-03-01

    Projectile fragmentation and fission, induced in collisions of 238 U at 1 A GeV with lead, have systematically been studied. A complete survey on the isotopic production cross sections of all elements between vanadium (Z = 23) and rhenium (Z = 75) down to a cross section of 0.1 mb is given. About 600 isotopes produced in fragmentation and about 600 isotopes produced in fission were identified in the GSI fragment separator FRS from magnetic rigidities, time-of-flight values, and the energy loss in an ionisation chamber. In addition, the velocity distributions of all these reaction products have been mapped, and the products are unambiguously attributed to the different reaction mechanisms due to their kinematical properties. The results are compared with empirical systematics and previous data. The velocity of the fragments obtained in the fission process by the Coulomb repulsion allows to reconstruct the TKE-value of the break-up and to identify the atomic number of the fissioning nucleus in hot fission. The mean velocities of light projectile fragments were found to be higher than the beam velocity. (orig.)

  13. High-resolution tephrochronology of the Wilson Creek Formation (Mono Lake, California) and Laschamp event using 238U-230Th SIMS dating of accessory mineral rims

    Science.gov (United States)

    Vazquez, Jorge A.; Lidzbarski, Marsha I.

    2012-01-01

    Sediments of the Wilson Creek Formation surrounding Mono Lake preserve a high-resolution archive of glacial and pluvial responses along the eastern Sierra Nevada due to late Pleistocene climate change. An absolute chronology for the Wilson Creek stratigraphy is critical for correlating the paleoclimate record to other archives in the western U.S. and the North Atlantic region. However, multiple attempts to date the Wilson Creek stratigraphy using carbonates and tephras yield discordant results due to open-system effects and radiocarbon reservoir uncertainties as well as abundant xenocrysts. New ion microprobe 238U-230Th dating of the final increments of crystallization recorded by allanite and zircon autocrysts from juvenile pyroclasts yield ages that effectively date eruption of key tephra beds and delimit the timing of basal Wilson Creek sedimentation to the interval between 26.8±2.1 and 61.7±1.9 ka. Tephra (Ash 15) erupted during the geomagnetic excursion originally designated the Mono Lake excursion yields an age of 40.8±1.9 ka, indicating that the event is instead the Laschamp excursion. The new ages support a depositional chronology from magnetostratigraphy that indicates quasi-synchronous glacial and hydrologic responses in the Sierra Nevada and Mono Basin to regional climate change, with intervals of lake filling and glacial-snowpack melting that are in phase with peaks in spring insolation.

  14. Vertical and horizontal distribution of radionuclides (232Th, 238U and 40K) in sediment from Manjung coastal water area Perak, Malaysia

    International Nuclear Information System (INIS)

    Abdullah, Anisa; Hamzah, Zaini; Wood, Ab. Khalik; Saat, Ahmad

    2016-01-01

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides ( 232 Th, 238 U and 40 K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (I geo ) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (H ex )

  15. Search for long-lived superheavy elements in the reaction system 238U + 9.6-MeV/nucleon 63/sub,/65Cu

    International Nuclear Information System (INIS)

    Esterlund, R.A.; Molzahn, D.; Brandt, R.; Patzelt, P.; Vater, P.; Boos, A.H.; Chandratillake, M.R.; Grant, I.S.; Hemingway, J.D.; Newton, G.W.A.

    1977-01-01

    A thick 238 U target has been bombarded with 63 /sub,/ 65 Cu ions at an incident beam energy of 9.6 MeV/nucleon. After radiochemical separations into CdS, HgS, and La-oxalate fractions, a search for evidence of the production of superheavy elements was undertaken using Si surface-barrier detectors and mica foils simultaneously for detection of spontaneous-fission events and high-energy α emission. No evidence for the presence of superheavy elements in the samples was found. Upper limits for production cross sections for superheavy elements in each of the three chemical samples, assuming an arbitrary half-life of 100 days and a target thickness equal to the entire reaction range of the incident ions from initial energy to the reaction barrier, are as follows: (a) CdS (Z = 108--115): 1 x 10 -34 cm 2 ; (b) HgS (Z = 112): 6 x 10 -35 cm 2 ; (c) La-oxalate ( 254 Cf): 8 x 10 -35 cm 2

  16. Temporal evolution of natural radionuclides distributions {sup 238}U, {sup 234}Th, {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 210}Po in the Bransfield strait, Antarctica peninsula; Evolucao temporal das distribuicoes dos radionuclideos naturais {sup 238}U, {sup 234}Th, {sup 226}Ra, {sup 228}Ra, {sup 210}Pb and {sup 210}Po no estreito de Bransfiel, peninsula Antartica

    Energy Technology Data Exchange (ETDEWEB)

    Lapa, Flavia Valverde

    2013-07-01

    Research on the distribution of natural radionuclides in Antarctica is rare and thus, there is great interest in to know their occurrence and factors related to its mobilization, transference and accumulation in this extremely fragile environment. Natural radionuclides have been used intensively as tracers in the ocean, helping to better understand processes as sinking and particle resuspension, water masses mixture and oceanic circulation. {sup 234}Th (t½ = 24.1 days) is a particle-reactive radionuclide produced continuously in seawater by the decay of its soluble precursor conservative with salinity {sup 238}U (t½ = 4.5 10{sup 9} years). Since {sup 234}Th presents relatively short half-life, it is used to quantify processes that occur in temporal scale varying from days to weeks. The disequilibrium {sup 234}Th/{sup 238}U in the surface ocean has been applied to estimate carbon fluxes exported via sinking material. The flux of particles biologically productive out of the euphotic zone in the Southern Ocean has special attention due to its importance in the control of CO{sub 2} atmospheric concentrations. The radionuclides {sup 210}Pb (t½ = 22.3 years) and {sup 210}Po (t½ = 138 days) are also particle-reactive. The disequilibrium {sup 210}Po/{sup 210}Pb has been used to estimate fluxes of particles exported in the ocean in the time scale of weeks. The long-lived Ra isotopes, {sup 226}Ra (t½ = 1,600 years) and {sup 228}Ra (t½ = 5.75 years) are soluble in seawater, presenting unique properties that make them excellent tracers of water masses. This research work had the aim to study the distributions of natural radionuclides {sup 238}U, {sup 234}Th, {sup 22}'6Ra, {sup 22}'8Ra, {sup 210}Pb and {sup 210}Po in the Bransfield Strait during 2 samplings carried out in the 2011 Austral Summer (OPERANTAR XXIX and XXX). (author)

  17. Stability of semiconductor memory characteristics in a radiation environment

    OpenAIRE

    Fetahović, I.; Vujisić, M.; Stanković, K.; Dolićanin, E.

    2015-01-01

    Radiation defects in electronic device can occur in a process of its fabrication or during use. Miniaturization trends in industry and increase in level of integration of electronic components have negative affect on component's behavior in a radiation environment. The aim of this paper is to analyze radiation effects in semiconductor memories and to establish how ionizing radiation influences characteristics and functionality of semiconductor memories. Both the experimental procedure and sim...

  18. Determination of 238U, 226Ra, 228Ra and 40K in grapes and wines of Valley of the Sao Francisco

    International Nuclear Information System (INIS)

    Silveira, Patricia Brandao da

    2007-01-01

    0.05 and 0.16 ± 0.01 to 0.45 ± 0.08 Bq L-1, respectively. The values of 238 U, on the other hand, ranged from 8.7 ± 1 to 10 ± 1 and 1.4 ± 0.4 to 3.2 ± 0.9 Bq L-1 for samples of pulp and wine, respectively. Concentrations obtained for 40 K stayed between 43 ± 1 to 56 ± 2 for pulp and 85 ± 2 to 94 ± 1 Bq L-1 for wine. 238 U presented the greatest activity concentration in the samples of pulp and wine. The levels of 226 Ra and 40 K are in agreement with the values found in the literature for both pulp and wine. In soil samples, on the other hand, 226 Ra and 228 Ra have activity concentrations above the reference values recommended by UNSCEAR. (author)

  19. Biogeochemical responses to late-winter storms in the Sargasso Sea, III—Estimates of export production using 234Th: 238U disequilibria and sediment traps

    Science.gov (United States)

    Maiti, Kanchan; Benitez-Nelson, Claudia R.; Lomas, Michael W.; Krause, Jeffrey W.

    2009-06-01

    Direct measurements of new production and carbon export in the subtropical North Atlantic Ocean appear to be too low when compared to geochemical-based estimates. It has been hypothesized that episodic inputs of new nutrients into surface water via the passage of mesoscale eddies or winter storms may resolve at least some of this discrepancy. Here, we investigated particulate organic carbon (POC), particulate organic nitrogen (PON), and biogenic silica (BSiO 2) export using a combination of water column 234Th: 238U disequilibria and free-floating sediment traps during and immediately following two weather systems encountered in February and March 2004. While these storms resulted in a 2-4-fold increase in mixed layer NO 3 inventories, total chlorophyll a and an increase in diatom biomass, the systems were dominated by generally low 234Th: 238U disequilibria, suggesting limited particle export. Several 234Th models were tested, with only those including non-steady state and vertical upwelling processes able to describe the observed 234Th activities. Although upwelling velocities were not measured directly in this study, the 234Th model suggests reasonable rates of 2.2-3.7 m d -1. Given the uncertainties associated with 234Th derived particle export rates and sediment traps, both were used to provide a range in sinking particle fluxes from the upper ocean during the study. 234Th particle fluxes were determined applying the more commonly used steady state, one-dimensional model with element/ 234Th ratios measured in sediment traps. Export fluxes at 200 m ranged from 1.91±0.20 to 4.92±1.22 mmol C m -2 d -1, 0.25±0.08 to 0.54±0.09 mmol N m -2 d -1, and 0.22±0.04 to 0.50±0.06 mmol Si m -2 d -1. POC export efficiencies (Primary Production/Export) were not significantly different from the annual average or from time periods without storms, although absolute POC fluxes were elevated by 1-11%. This increase was not sufficient, however, to resolve the discrepancy

  20. 40Ar/ 39Ar, K-Ar and 230Th- 238U dating of the Laschamp excursion: A radioisotopic tie-point for ice core and climate chronologies

    Science.gov (United States)

    Singer, Brad S.; Guillou, Hervé; Jicha, Brian R.; Laj, Carlo; Kissel, Catherine; Beard, Brian L.; Johnson, Clark M.

    2009-08-01

    A brief period of enhanced 10Be flux that straddles the interstadial warm period known as Dansgaard-Oeschger event 10 in Greenland and its counterpart in Antarctica, the Antarctic Isotope Maximum 10 is but one consequence of the weakening of Earth's magnetic field associated with the Laschamp excursion. This 10Be peak measured in the GRIP ice core is dated at 41,250 y b2k (= before year 2000 AD) in the most recent GICC05 age model obtained from the NorthGRIP core via multi-parameter counting of annual layers. Uncertainty in the age of the 10Be peak is, however, no better than ± 1630 y at the 95% confidence level, reflecting accumulated error in identifying annual layers. The age of the Laschamp excursion [Guillou, H., Singer, B.S., Laj, C., Kissel, C., Scaillet, S., Jicha, B., 2004. On the age of the Laschamp geomagnetic excursion. Earth Planet. Sci. Lett. 227, 331-343.] is revised on the basis of new 40Ar/ 39Ar, unspiked K-Ar and 238U- 230Th data from three lava flows in the Massif Central, France, together with the 40Ar/ 39Ar age of a transitionally magnetized lava flow at Auckland, New Zealand. Combined, these data yield an age of 40,700 ± 950 y b2k, where the uncertainty includes both analytical and systematic ( 40K and 230Th decay constant) errors. Taking the radioisotopic age as a calibration tie point suggests that the layer-counting chronologies for the NorthGRIP and GISP2 ice cores are more accurate and precise than previously thought at depths corresponding to the Laschamp excursion.

  1. Thallium, uranium, and 235U/238U ratios in the digestive gland of American lobster (Homarus americanus) from an industrialized harbor

    International Nuclear Information System (INIS)

    Chou, C.L.; Uthe, J.F.

    1995-01-01

    Only a few studies have concentrated on elements such as thallium (TI). Uranium (U) has been studied as a radionuclide of concern in food and the environment. Foodstuffs contain 10-100 ng U· -1 with vegetables and cereals contributing most heavily to the daily intake of ca 1.5 ug U. Between 10-30% of ingested U is absorbed, with most being stored in bone. Rainbow trout (onchorynchus mykiss) and longnose sucker (Catostomus catostomus) from a lake with naturally high radioactivity contained -1 in the flesh. Trout bone contained 40 ng U·g -1 . Higher tissue U concentrations occurred in fish from areas receiving U mining wastes. Bioconcentration factors for bone and flesh were estimated to be low, 118 and 14.7, respectively. This paper describes the Inductively coupled plasma-mass spectrometry (ICP-MS) determination of Tl and U in digestive gland tissue from lobsters captured in the vicinity of Belledune Harbor, New Brunswick, Canada. The harbor is the site of a lead smelter, a fertilizer plant, and a coal-fired power station (the latter due to enter production in late 1993) and thus has the potential of adding significant amounts of Tl to the local marine environment. The accumulation of Tl from water by marine shellfish is low, at least for bivalves, and the accumulated Tl is eliminated in a number of days when the animals are transferred to clean water. Bioconcentration factors for U in finfish ranged from 0.4-17 for larger species. However, because of the high concentrations of various trace elements in lobster digestive gland, its desirability as a foodstuff, and its relatively large size (approximately 20% of the edible tissue yield), we have investigated Tl and U concentrations and 235U / 238U ratios in it. 15 refs., 1 fig., 3 tabs

  2. Theoretical analyses of (n,xn) reactions on sup 235 U, sup 238 U, sup 237 Np, and sup 239 Pu for ENDF/B-VI

    Energy Technology Data Exchange (ETDEWEB)

    Young, P.G.; Arthur, E.D.

    1991-01-01

    Theoretical analyses were performed of neutron-induced reactions on {sup 235}U, {sup 238}U, {sup 237}Np, and {sup 239}Pu between 0.01 and 20 MeV in order to calculate neutron emission cross sections and spectra for ENDF/B-VI evaluations. Coupled-channel optical model potentials were obtained for each target nucleus by fitting total, elastic, and inelastic scattering cross section data, as well as low-energy average resonance data. The resulting deformed optical model potentials were used to calculate direct (n,n{prime}) cross sections and transmission coefficients for use in Hauser-Feshbach statistical theory analyses. A fission model with multiple barrier representation, width fluctuation corrections, and preequilibrium corrections were included in the analyses. Direct cross sections for higher-lying vibrational states were calculated using DWBA theory, normalized using B(E{ell}) values determined from (d,d{prime}) and Coulomb excitation data, where available, and from systematics otherwise. Initial fission barrier parameters and transition state density enhancements appropriate to the compound systems involved were obtained from previous analyses, especially fits to charged-particle fission probability data. The parameters for the fission model were adjusted for each target system to obtain optimum agreement with direct (n,f) cross section measurements, taking account of the various multichance fission channels, that is, the different compound systems involved. The results from these analyses were used to calculate most of the neutron (n,n), (n,n{prime}), and (n,xn) cross section data in the ENDF/B/VI evaluations for the above nuclei, and all of the energy-angle correlated spectra. The deformed optical model and fission model parameterizations are described. Comparisons are given between the results of these analyses and the previous ENDF/B-V evaluations as well as with the available experimental data. 14 refs., 3 figs., 1 tab.

  3. Assessment of airborne 238U and 232Th exposure and dust load impact on people living in the vicinity of a cement factory in Ghana

    International Nuclear Information System (INIS)

    Addo, Moses Ankamah; Gbadago, J.K.; Ameyaw, Felix; Darko, E.O.; Gordon, Chris; Davor, Peter; Faanu, A.; Kpeglo, David

    2014-01-01

    Globally, the cement industry has been identified as one which causes significant particle pollution. In Ghana, environmental research in the neighborhood of the cement industry especially on human health is scanty. In the present work, attempts were made to evaluate the concentration of airborne dust at various distances and directions around the Diamond Cement Factory in the Volta Region of Ghana. The samples of dust were collected on filter papers and later analyzed for the concentration (mg/kg) of 232 Th and 23 '8U using neutron activation analysis. The principal objective of the study was to generate data intended at assessing the annual effective dose due to 232 Th and 238 U inhalation for both adult and children population living in the vicinity of cement factory. The data generated were supposed to assist in remediation decision making, if required. The study recorded a few incidences of higher total dust load concentrations as compared to the permissible limit of 150 μg/m 3 specified by the Ghana Environmental Protection Agency. The calculated mean effective doses were 28.2 ± 1.06 μSv/year and 25.9 ± 0.91 μSv/year for both adult and child, respectively. From the radiological point of view, the study concluded that the people living in the vicinity of the cement factory are not at risk to significant radiological hazards. However, the study indicated the need to have a complete evaluation of the impact of the factory on the environment assessment programs which should include both chemical and radiological toxicity. (author)

  4. Extensive radioactive characterization of a phosphogypsum stack in SW Spain: {sup 226}Ra, {sup 238}U, {sup 210}Po concentrations and {sup 222}Rn exhalation rate

    Energy Technology Data Exchange (ETDEWEB)

    Abril, Jose-Maria, E-mail: jmabril@us.es [Dpto. Fisica Aplicada I, Universidad de Sevilla, EUITA, Ctra Utrera Km 1, 41013 Seville (Spain); Garcia-Tenorio, Rafael, E-mail: gtenorio@us.es [Dpto. Fisica Aplicada II, Universidad de Sevilla, ETSA, Avda. Reina Mercedes s/n, 41012 Seville (Spain); Manjon, Guillermo, E-mail: manjon@us.es [Dpto. Fisica Aplicada II, Universidad de Sevilla, ETSA, Avda. Reina Mercedes s/n, 41012 Seville (Spain)

    2009-05-30

    Phosphogypsum (PG) is a by-product of the phosphate fertilizer industries that contains relatively high concentrations of uranium series radionuclides. The US-EPA regulates the agriculture use of PG, attending to its {sup 226}Ra content and to the {sup 222}Rn exhalation rate from inactive stacks. Measurements of {sup 222}Rn exhalation rates in PG stacks typically show a large and still poorly understood spatial and temporal variability, and the published data are scarce. This work studies an inactive PG stack in SW Spain of about 0.5 km{sup 2} from where PG can be extracted for agriculture uses, and an agriculture soil 75 km apart, being representative of the farms to be amended with PG. Activity concentrations of {sup 226}Ra, {sup 238}U and {sup 210}Po have been measured in 30 PG samples (0-90 cm horizon) allowing for the construction of maps with spatial distributions in the PG stack and for the characterization of the associated PG inputs to agriculture soils. Averaged {sup 226}Ra concentrations for the stack were 730 {+-} 60 Bq kg{sup -1} (d.w.), over the US-EPA limit of 370 Bq kg{sup -1}. {sup 222}Rn exhalation rate has been measured by the charcoal canister method in 49 sampling points with 3 canisters per sampling point. Values in PG stack were under the US-EPA limit of 2600 Bq m{sup -2} h{sup -1}, but they were one order of magnitude higher than those found in the agriculture soil. Variability in radon emissions has been studied at different spatial scales. Radon exhalation rates were correlated with {sup 226}Ra concentrations and daily potential evapotranspiration (ETo). They increased with ETo in agriculture soils, but showed an opposite behaviour in the PG stack.

  5. 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.

  6. Application of 234U/238U isotope ratio data for the study of geochemical problems associated with local water sources from Aguas da Prata (SP, Brazil)

    International Nuclear Information System (INIS)

    Bonotto, D.M.

    1982-01-01

    The uranium-238, uranium-234 and radon content of spring waters of Aguas da Prata (SP) - Platina, Paiol, Villela, Sao Bento, Prata-Radioativa, Prata-Nova, Boi, Vitoria and Prata-Antiga - was found; the activity ratio AR ( 234 U/ 238 U) was applied to the geochemistry of local water sources. The uranium analysis procedure consisted of the following steps: adition of 232 U- 228 Th spike to the samples, coprecipitation with iron, iron extraction with organic solvent, separation on anion-exchange resin, extraction with TTA, deposition on stainless steel disc and determination of uranium content by alpha spectrometry. The uranium-238 content changed from 0,10 to 11,56 ppb (average value = 2,3 ppb). The higher values were observed for the waters circulating through sandstones and the lower through volcanic rocks. The inverse correlation (r sub(s) =-0,76) between pH and uranium-238 content confirmed the contribution of this factor on its solubility. The significative correlation r sub(s) = 0,76 between dissolved oxygen and uranium-238 content also confirmed the higher uranium on the more oxidizing zones. The AR changed from 2,84 to 11,68 (average value = 6). These values defined the regional aquifer systems as mineralized in uranium. The higher AR were observed for the deep groundwaters and the lower for the shallow one. Because the 238 U→ 234 Th decay, the 234 Th ejection to the solution was confirmed as the most important factor responsible for the extreme observed isotopic fractionation. (Author) [pt

  7. Determination of uranium isotopes (235U, 238U) and trace elements (Cd, Pb, Cu and As) in bottled drinking water by Icp-SFMS

    International Nuclear Information System (INIS)

    Lara A, N.; Hernandez M, H.; Romero G, E. T.; Kuri de la C, A.; Perez B, M. A.

    2016-09-01

    In the present work we propose an optimized method for the quantification of uranium isotopes ( 235 U, 2 38 U) and the elements Cd, Pb, Cu and As in bottled water for drinking at trace levels of concentration. Based on the multi-element detection capability, the high sensitivity and resolution that the Mass Spectrometry with Magnetic Sector with Inductively Coupled Plasma Source (Icp-SFMS) technique offers; the high, medium and low resolution analysis conditions for the elements under study were established and optimized using and Element 2/Xr equipment and the 23 multi-elemental Certified Reference Material (CRM). The analysis method was validated using the standard reference material Nist 1643d and CRM mono-elemental s as external standards for the quantification of the analytes. Samples, targets and CRM were acidified with 2% of HNO 3 and analyzed without pretreatment under the established analysis conditions. The results obtained show concentrations of 235 U, 238 U, 111 Cd, 208 Pb, 63 Cu and 75 As in the range of μg L -1 , the linearity obtained from the calibration curves for each element has correlation coefficients < 0.99 in all cases, the accuracy of the method in terms of percent relative standard deviation (RSD %) was less than 5%, the mean recovery rate of Nist 1643d ranged from 96.46% to 101.12%. The optimization of the method guarantees the stability and calibration of the equipment throughout the analysis, as well as the ability to resolve interferences. In conclusion, the method proposed using Icp-SFMS offers the advantages of being fast and simple for the multi-elemental analysis in water at trace levels, with low limits of quantification and detection, with good linearity, accuracy, precision and reproducibility to a degree of reliability of 95%. (Author)

  8. Synchrotron radiation: its characteristics and applications

    International Nuclear Information System (INIS)

    Blewett, J.P.; Chasman, R.; Green, G.K.

    1977-01-01

    It has been known for a century that charged particles radiate when accelerated and that relativistic electrons in the energy range between 100 MeV and several GeV and constrained to travel in circular orbits emit concentrated, intense beams with broad continuous spectra that can cover the electromagnetic spectrum from infrared through hard X-rays. Recently the possible applications of this radiation have been appreciated and electron synchrotrons and electron storage rings are now being used in many centers for studies of the properties of matter in the solid, liquid and gaseous states. A brief history is presented of ''synchrotron radiation'' as it is now called. The basic properties of this radiation are described and the world-wide distribution is indicated of facilities for its production. Particular attention is given to the proposed facility at Brookhaven which will be the first major installation to be dedicated only to the production and use of synchrotron radiation. Finally, typical examples are given of applications in the areas of radiation absorption studies, techniques based on scattering of radiation, and advances based on X-ray lithography

  9. Standard practice for the determination of 237Np, 232Th, 235U and 238U in urine by inductively coupled plasma-Mass spectrometry (ICP-MS) and gamma ray spectrometry.

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This practice covers the separation and preconcentration of neptunium-237 (237Np), thorium-232 (232Th), uranium-235 (235U) and uranium-238 (238U) from urine followed by quantitation using ICP-MS. 1.2 This practice can be used to support routine bioassay programs. The minimum detectable concentrations (MDC) for this method, taking the preconcentration factor into account, are approximately 1E-2Bq for 237Np (0.38ng), 2E-6Bq for 232Th (0.50ng), 4E-5Bq for 235U (0.50ng) and 6E-6Bq for 238U (0.48ng). 1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  10. Studying Angular Distribution of Neutron for (p,n) Reaction from 0.5 GeV to 1.5 GeV on some Heavy Targets 238U, 206Pb, 197Au, 186W

    International Nuclear Information System (INIS)

    Nguyen Mong Giao; Tran Thanh Dung; Nguyen Thi Ai Thu; Huynh Thi Xuan Tham

    2010-08-01

    The angular distributions of neutron are calculated for a spallation reaction induced by proton energy from 0.5 GeV to 1.5 GeV on target nuclei 206 Pb, 197 Au, 238 U, 186 W. In this report, we use nuclear data of JENDL-HE with evaluated proton induced cross-sections up to 3 GeV. The obtained results have been discussed in detail. (author)

  11. Beta and gamma decay heat measurements between 0.1s--50,000s for neutron fission of 235U, 238U and 239Pu. Final report, June 1, 1992--December 31, 1996

    International Nuclear Information System (INIS)

    Schier, W.A.; Couchell, G.P.

    1996-01-01

    This is a final reporting on the composition of separate beta and gamma decay heat measurements following neutron fission of 235 U and 238 U and 239 Pu and on cumulative and independent yield measurements of fission products of 235 U and 238 U. What made these studies unique was the very short time of 0.1 s after fission that could be achieved by incorporating the helium jet and tape transport system as the technique for transporting fission fragments from the neutron environment of the fission chamber to the low-background environment of the counting area. This capability allowed for the first time decay heat measurements to extend nearly two decades lower on the logarithmic delay time scale, a region where no comprehensive aggregate decay heat measurements had extended to. This short delay time capability also allowed the measurement of individual fission products with half lives as short as 0.2s. The purpose of such studies was to provide tests both at the aggregate level and at the individual nuclide level of the nation's evaluated nuclear data file associated with fission, ENDF/B-VI. The results of these tests are in general quite encouraging indicating this data base generally predicts correctly the aggregate beta and aggregate gamma decay heat as a function of delay time for 235 U, 238 U and 239 Pu. Agreement with the measured individual nuclide cumulative and independent yields for fission products of 235 U and 238 U was also quite good although the present measurements suggest needed improvements in several individual cases

  12. Development of sequential analytical method for the determination of U-238, U-234, Th-232, Th-230, Th-228, Ra-226 and Ra-228 and its application in mineral waters

    International Nuclear Information System (INIS)

    Costa Lauria, D. da.

    1986-01-01

    A sequential analytical method for the determination of U-238, U-234, Th-232, Th-230, Th-228, Ra-226 and Ra-228 in environmental samples and applied to the analysis of mineral waters is studied. Thorium isotopes are coprecipitated with lanthanium fluoride before counting in alpha spectrometer, the uranium isotopes are determined by alpha spectrometry following extraction with TOPO onto a polymenic membrane. Radium-226 is determined with the radom emanation technique. (M.J.C.) [pt

  13. Photofission cross-section ratio measurement of {sup 235}U/{sup 238}U using monoenergetic photons in the energy range of 9.0–16.6 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Krishichayan, E-mail: krishi@tunl.duke.edu [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Bhike, Megha; Finch, S.W.; Howell, C.R. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Tonchev, A.P. [Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Tornow, W. [Department of Physics, Duke University, Durham, NC 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States)

    2017-05-11

    Photofission cross-section ratios of {sup 235}U and {sup 238}U have been measured using monoenergetic photon beams at the HIγS facility of TUNL. These measurements have been performed in small energy steps between 9.0 and 16.6 MeV using a dual-fission ionization chamber. Measured cross-section ratios are compared with the previous experimental data as well as with the recent evaluated nuclear data library ENDF.

  14. Determination of uranium concentrations and "2"3"4U/"2"3"8U activity ratio in some granitic rock samples by alpha spectrometry: application of a radiochemical procedure

    International Nuclear Information System (INIS)

    Khattab, Mahmoud R.

    2016-01-01

    The present study is an application of a radiochemical procedure using alpha spectrometry technique for determination of uranium isotopes "2"3"8U, "2"3"4U and "2"3"5U on 13 granitic samples. These samples were collected from Gabal Gattar area, Northeastern Desert, Egypt. The collected samples were digested using microwave technique with aqua regia and spiked with "2"3"2U for chemical yield and activity calculation. Separation of uranium isotopes from the samples was done by Dowex 1 x 4 (50-100 mesh) resin followed by source preparation using microprecipitation technique. The concentrations of "2"3"8U were ranged between 28.9±0.9 and 134.8±1.8 Bq/g, and the "2"3"4U concentrations were between 24±0.6 and 147.7±2.2 Bq/g. For the "2"3"5U, the activity concentrations were between 1.3±0.2 and 6.7±1.2 Bq/g. The activity ratio of "2"3"4U/"2"3"8U was calculated and varied from 0.80 to 1.30. (author)

  15. Neutron Energy Spectra from Neutron Induced Fission of 235U at 0.95 MeV and of 238U at 1.35 and 2.02 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Almen, E; Holmqvist, B; Wiedling, T

    1971-09-15

    The shapes of fission neutron spectra are of interest for power reactor calculations. Recently it has been suggested that the neutron induced fission spectrum of 235U may be harder than was earlier assumed. For this reason measurements of the neutron spectra of some fissile isotopes are in progress at our laboratory. This report will present results from studies of the energy spectra of the neutrons emitted in the neutron induced fission of 235U and 238U. The measurements were performed at an incident neutron energy of 0.95 MeV for 235U and at energies of 1.35 and 2.02 MeV for 238U using time-of-flight techniques. The time-of-flight spectra were only analysed at energies higher than those of the incident neutrons and up to about 10 MeV. Corrections for neutron attenuation in the uranium samples were calculated using a Monte Carlo program. The corrected fission neutron spectra were fitted to Maxwellian temperature distributions. For 235U a temperature of 1.27 +- 0.01 MeV gives the best fit to the experimental data and for 238U the corresponding values are 1.29 +- 0.03 MeV at 1.35 MeV and 1.29 +- 0.02 MeV at 2.02 MeV

  16. Radiation resistant characteristics of optical fibers

    International Nuclear Information System (INIS)

    Nakasuji, Masaaki; Tanaka, Gotaro; Watanabe, Minoru; Kyodo, Tomohisa; Mukunashi, Hiroaki

    1983-01-01

    It is required to develop the optical fibers with good radiation resistivity because the fibers cause the increase of transmission loss due to glass colouring when they are used under the presence of radiation such as γ-ray. Generally, it is known that SI (step index) fibers are more resistive to radiation than GI (graded index) fibers. However, since a wide band can not be obtained with SI fibers, the development of radiation resistive GI optical fibers is desirable. In this report, the production for trial of the GI fibers of fluorine-doped silica core, the examination of radiation effect on their optical transmission loss by exposing them to γ-ray, thermal and fast neutron beams and also of mechanical strength are described. The GI fibers of fluorine-doped silica core show better radiation resistivity than Ge-doped ones. The B- and F-doped GI fibers show small increase of loss due to γ-ray, but large increase of loss due to thermal neutron beam. This is supposed to be caused by the far greater neutron absorption cross-section of boron than that of other elements. Significant increase of loss was not recognized when 14 MeV fast neutrons (8.6 x 10 4 n/cm 2 .s) were applied by 1.8 x 10 9 n/cm 2 . It was found that ETFE-covered fiber cores generated fluorine-containing gas due to γ irradiation, and the strength was remarkably lowered, but the lowering of strength can be prevented by adding titanium-white to the covering material. (Wakatsuki, Y.)

  17. Radiation oncologists in 2000: demographic, professional, and practice characteristics

    International Nuclear Information System (INIS)

    Cypel, Yasmin; Sunshine, Jonathan H.; Schepps, Barbara

    2002-01-01

    Purpose: To describe the demographic, professional, and practice characteristics of radiation oncologists, emphasizing comparisons to data from a similar 1995 Survey. Methods and Materials: In spring 2000, we surveyed 603 randomly selected radiation oncologists by mail, using a one-page questionnaire - 455 responded. We weighted responses to make answers representative of all radiation oncologists in the United States. Results: Approximately 45% of post-training, professionally active, radiation oncologists were <45 years old and 22% were women. Forty-two percent of radiation oncologists in training were women. Thirty-three percent of radiation-oncology-only practices were solo practices. The greatest percentage of post-training, professionally active, radiation oncologists were in nonacademic private radiation oncology practices. Fifty-three percent of post-training, professionally active, radiation oncologists reported that their workload was about right. Eighteen percent of individuals 60-64 years old and approximately two-thirds of those ≥65 years old were not working (retired). The full-time equivalency of those aged 55-74 fell by 12 percentage points between 1995 and 2000. Conclusions: Most demographic, professional, and practice characteristics remained relatively constant between 1995 and 2000, with the exception of work status patterns. Radiation oncologists reported a more balanced workload than that reported by diagnostic radiologists. The surplus of radiation oncologists, which was predicted in the mid-1990s, was not demonstrated

  18. Discriminating assimilants and decoupling deep- vs. shallow-level crystal records at Mount Adams using 238U-230Th disequilibria and Os isotopes

    Science.gov (United States)

    Jicha, B.R.; Johnson, C.M.; Hildreth, Wes; Beard, B.L.; Hart, G.L.; Shirey, S.B.; Singer, B.S.

    2009-01-01

    A suite of 23 basaltic to dacitic lavas erupted over the last 350??kyr from the Mount Adams volcanic field has been analyzed for U-Th isotope compositions to evaluate the roles of mantle versus crustal components during magma genesis. All of the lavas have (230Th/238U) > 1 and span a large range in (230Th/232Th) ratios, and most basalts have higher (230Th/232Th) ratios than andesites and dacites. Several of the lavas contain antecrysts (crystals of pre-existing material), yet internal U-Th mineral isochrons from six of seven lavas are indistinguishable from their eruption ages. This indicates a relatively brief period of time between crystal growth and eruption for most of the phenocrysts (olivine, clinopyroxene, plagioclase, magnetite) prior to eruption. One isochron gave a crystallization age that is ~ 20-25??ka older than its corresponding eruptive age, and is interpreted to reflect mixing of older and juvenile crystals or a protracted period of magma storage in the crust. Much of the eruptive volume since 350??ka consists of lavas that have small to moderate 230Th excesses (2-16%), which are likely inherited from melting of a garnet-bearing intraplate ("OIB-like") mantle source. Following melt generation and subsequent migration through the upper mantle, most Mt. Adams magmas interacted with young, mafic lower crust, as indicated by 187Os/188Os ratios that are substantially more radiogenic than the mantle or those expected via mixing of subducted material and the mantle wedge. Moreover, Os-Th isotope variations suggest that unusually large 230Th excesses (25-48%) and high 187Os/188Os ratios in some peripheral lavas reflect assimilation of small degree partial melts of pre-Quaternary basement that had residual garnet or Al-rich clinopyroxene. Despite the isotopic evidence for lower crustal assimilation, these processes are not generally recorded in the erupted phenocrysts, indicating that the crystal record of the deep-level 'cryptic' processes has been

  19. 234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California, USA

    International Nuclear Information System (INIS)

    Drexler, J.Z.; Paces, J.B.; Alpers, C.N.; Windham-Myers, L.; Neymark, L.A.; Bullen, T.D.; Taylor, H.E.

    2014-01-01

    Highlights: • Concentrations and isotopic values of Sr and U in peat were used to trace paleosalinity. • A three-end-member mixing model was constructed using values from water sources. • Paleosalinity of peat samples was determined relative to that of end members. • δ 87 Sr values were altered during and after the California Gold Rush period. • Oligohaline and freshwater marshes have long existed in the Sacramento-San Joaquin Delta. - Abstract: 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, δ 87 Sr values, and 234 U/ 238 U 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 137 Cs, the onset of Pb and Hg contamination from hydraulic gold mining, and 14 C. 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 (<0.5 ppt) through time. Therefore, the eastern Delta, which occurs upstream from Bacon Channel Island along the San Joaquin River and its

  20. Polonium (210Po) and uranium (234U, 238U) in water, phosphogypsum and their bioaccumulation in plants around phosphogypsum waste heap at Wislinka (nothern Poland)

    International Nuclear Information System (INIS)

    Skwarzec, B.; Borylo, A.; Kosinska, A.; Radzajewska, S.

    2010-01-01

    The principal sources of polonium and uranium radionuclides the Wislinka area waste dump are phosphorites and phosphogypsum produced by the Phosphoric Fertilizers Industry of Gdansk. The values of uranium and polonium concentration in water with immediate surroundings of waste heap are considerably higher than in the waters of the Martwa Wisla river. The activity ratio 234 U/ 238 U is approximately about one in the phosphogypsum (0.97±0.06 and 0.99±0.04) and in the water of a retention reservoir and a pumping station (0.92±0.01 and 0.99±0.04), while in the water from the Martwa Wisla river is slightly higher than one (1.00±0.07 and 1.06±0.02). The leaching process of uranium and polonium from the phosphogypsum waste heap is responsible for the maximum uranium concentration (1097±6 μg·dm -3 and 1177±6 μg·dm -3 ) and the high 210 Po concentration (131.4±0.9 mBq·dm -3 and 165.7±1.4 mBq·dm -3 ) in the retention reservoir. The major source of polonium and uranium in plants are wet and dry atmospheric falls gathering soil and air dust from the phosphogypsum waste dump and root system. The highest uranium and polonium concentrations were found in older part of grasses (yellow oatgrass, meadow foxtail, moneywort), exposed to atmospheric falls for a long time. The maximum concentrations of 210 Po were characterized for samples of plant root collected at the retention reservoir (150.50±4.97 and 108.55±3.95 Bq·kg -1 dry mass). Polonium and uranium concentrations in water samples of the Martwa Wisla river are relatively low in comparison with the value in the retention reservoir and pumping station near the phosphogypsum waste heap. This suggests that the radionuclides could be leached from the dumping site to the surrounding environment. (authors)

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

    Directory of Open Access Journals (Sweden)

    Gooden Matthew

    2017-01-01

    Full Text Available 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.

  2. Radiative characteristics of the Chelyabinsk superbolide

    Science.gov (United States)

    Yanagisawa, Masahisa

    2015-12-01

    On Feb. 15, 2013, a meteoroid with a size of about 19 m plunged into the terrestrial atmosphere at 19 km s-1 and burst at an altitude of about 30 km over the city of Chelyabinsk, Russia. Here we present light curves for the bolide in the red, green, and blue color bands, derived from an analysis of a video that was recorded by a dashboard camera and released on the Internet. Our results demonstrate that the bolide was blue-green in color, which is inconsistent with the Planck spectrum before the meteoroid began to fragment. Fragmentation triggered a flare-up of the bolide and 90% of its radiation energy at optical wavelengths was released within a period of about 2 s after that. During the same period, the brightness ratios among the three bands became consistent with 4000 K blackbody radiation. Based on the peak luminosity, a surface area of several square kilometers would be required for a 4000 K blackbody. It is considered that the radiation source of the bolide was an elongated cloud of vapor and debris produced through severe fragmentation of the meteoroid.

  3. Phase Radiation Characteristics of an Open-Ended Circular Waveguide

    DEFF Research Database (Denmark)

    Shishkova, A.V.; Pivnenko, Sergiy; Kim, O.S.

    2002-01-01

    Analytic expressions for phase radiation characteristics of a semi-infinite open-ended circular waveguide regardless of its aperture size and operating frequency have been obtained making use of the rigorous Weinstein's theory. The analysis of phase radiation patterns has been carried out...... for the dominant mode (TE11) as well as for the high order modes TM01 and TE01, both for a single and multimode propagation. The measurement of radiation characteristics of an open-ended circular waveguide has been carried out at the DTU-ESA Spherical Near-Field Antenna Test Facility. It is shown...

  4. The baffle influence on sound radiation characteristics of a plate

    Directory of Open Access Journals (Sweden)

    Bao Liu

    2017-01-01

    Full Text Available The acoustic radiation characteristics of the baffle plates and unbaffle plates are calculated and compared by single-layer potential and double-layer potential. Based on the boundary integral equation, the sound pressure integral equation of the baffle and the baffle are deduced respectively. According to the boundary compatibility condition, the sound pressure and the vibration velocity of the plates are obtained. Further, the dynamic equation of the structure is substituted into the vibration equation in the form of the baffle plate and the baffle plate. The sound pressure difference and the displacement of a plate surface are in the form of the vibration mode superposition and the acoustic radiation impedance of the double integral form is obtained, which determines vibration mode coefficient and sound radiation parameters. The effect of the baffle on the acoustic radiation characteristics of the thin plate is analyzed by comparing the acoustic radiation parameters with the simple and simple rectangular plate in water.

  5. Correlation of the activity of the {sup 238} U in soil and {sup 222} Rn in domiciles, with the rocks of cities of the Estado de Chihuahua; Correlacion de la actividad del {sup 238} U en suelo y {sup 222} Rn en domicilios, con las rocas de ciudades del Estado de Chihuahua

    Energy Technology Data Exchange (ETDEWEB)

    Colmenero S, L.; Villalba, L.; Montero C, M.E. [Centro de Investigacion en Materiales Avanzados (CIMAV), Av. Miguel de Cervantes 120 C.P. 31109 Chihuahua (Mexico)]. e-mail: luis.colmenero@cimav.edu.mx

    2004-07-01

    The state of Chihuahua has numerous locations of uranium, being Pena Blanca the great and more important location of the country. Diverse rock types with important quantities of uranium are distributed by the whole state. The igneous extrusive acid rocks are those that have bigger quantity of uranium, like they are the rhyolites and dacites and these rocks are located in enough proportion by the whole state. Some of the main cities of the state are near to locations or uraniferous rocks, as Aldama, Nuevo Casas Grandes, Chihuahua, Jimenez and Bocoyna, other important cities are not near important locations. It was determined specific activity by gamma spectroscopy of the series of the {sup 238} U in soils and determination of the radon concentration in domiciles of the main cities of the state. They were found high specific activity values in soil in eight of the thirteen analyzed cities and important radon concentrations in three cities. It was found relationship among the specific activity in soil in near cities to uraniferous locations. (Author)

  6. Feasibility of Colliding-beam fast-fission reactor via 238U80++238 U80+ --> 4 FF + 5n + 430 MeV beam with suppressed plutonium and direct conversion of fission fragment (FF) energy into electricity and/or Rocket propellant with high specific impulse

    Science.gov (United States)

    Maglich, Bogdan; Hester, Tim; Calsec Collaboration

    2015-10-01

    Uranium-uranium colliding beam experiment1, used fully ionized 238U92+ at energy 100GeV --> accelerated through 3 MV accelerator, will collide beam 240 MeV --> 4 FF + 5n + 430 MeV. Using a simple model1 fission σf ~ 100 b. Suppression of Pu by a factor of 106 will be achieved because NO thermal neutron fission can take place; only fast, 1-3 MeV, where σabs is negligible. Direct conversion of 95% of 430 MeV produced is carried by electrically charged FFs which are magnetically funneled for direct conversion of energy of FFs via electrostatic decelerators4,11. 90% of 930 MeV is electrically recoverable. Depending on the assumptions, we project electric _ power density production of 20 to 200 MWe m-3, equivalent to Thermal 1.3 - 13 GWthm-3. If one-half of unburned U is used for propulsion while rest powers system, heavy FF ion mass provides specific impulse Isp = 106 sec., 103 times higher than current rocket engines.

  7. 187Re - 232Th - 238U nuclear geochronometry: constraining magmatism in East-Antarctica and the break-up of Gondwana

    Science.gov (United States)

    Roller, Goetz

    2017-04-01

    187Re - 232Th - 238U nuclear geochronometry is a new dating method for astronomy, earth and planetary sciences [1-4]. Nucleogeochronometric Rhenium-Osmium two-point-isochron (TPI) ages are calculated using a nuclear geochronometer as one data point in a two-point-isochron diagram [5-7]. The IVREA chronometer, for example, is one of five terrestrial nuclear geochronometers identified so far [8]. Here, it is used to constrain the magmatism of the Ferrar flood basalt province, which has been related to continental rifting and the break-up of Gondwana in the Jurassic.TPI ages for seven (basaltic) andesite whole rock samples from the Prince Albert Mountains (Victoria Land, Antarctica) are calculated. An isochron age of 172 ± 5 Ma (187Os/188Osi = 0.194 ± 0.023) has previously been published for these rocks [9]. Initial TPI 187Os/188Osi ratios show only minor scatter between 187Os/188Osi = 0.2149 ± 0.0064 and 187Os/188Osi = 0.22231 ± 0.00080, in agreement with the enigmatic, suprachondritic 187Os/188Osi = 0.194 ± 0.023 from the isochron [9]. TPI ages for the Mount Joyce samples range from 125.4 ± 9.9 Ma to 139 ± 17 Ma and thus constrain the youngest magmatic event(s) in the Transantarctic Mountains. For the Thumb Point basalt, a TPI age of 219 ± 81 Ma is calculated. Despite of its large uncertainty, the age itself is in agreement with the Triassic 224 Ma and 240 Ma events reported from North Patagonia [10]. The TPI age of 186.1 ± 8.1 Ma from the Ricker Hill basalt can be clearly distinguished from the Mount Murray TPI age of 158 ± 14 Ma, while at Brimstone Peak two TPI age groups of 155 ± 14 Ma and 175.3 ± 3.1 Ma are observed. From this it may be concluded that the seven TPI ages indicate episodic magmatic activity in East-Antarctica between 125 Ma and 219 Ma, leading to the break-up of Gondwana. This picture is consistent with the geochronology of the Antarctic Peninsula, Patagonia, the Karoo and the Ferrar mafic rocks [10]. Thus, besides constraining

  8. Mass measurements of {sup 238}U-projectile fragments for the first time with a multiple-reflection time-of-flight mass spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, Jens

    2016-07-01

    Mass measurements of short-lived uranium projectile fragments were performed for the first time with a Multiple-Reflexion-Time-of-Flight Mass Spectrometer (MR-TOF-MS). A major part of this doctoral work was a novel development of a data analysis method for the MR-TOF-MS mass measurements of exotic nuclei at the fragment separator FRS at GSI. The developed method was successfully applied to the data obtained from two pilot experiments with the MR-TOF-MS at the FRS in 2012 and 2014. A substantial upgrade of the experimental setup of the MR-TOF-MS was also performed in the frame work of this doctoral thesis after the first run. In the experiments projectile fragments were created with 1000 MeV/u {sup 238}U ions in a Be/Nb target at the entrance of the in-flight separator FRS. The exotic nuclei were spatially separated, energy bunched and slowed down with the ion-optical system of the FRS combined with monoenergetic and homogeneous degraders. At the final focal plane of the FRS the fragments were completely slowed down and thermalized in a cryogenic stopping cell (CSC) filled with 3-5 mg/cm{sup 2} pure helium gas. The exotic nuclei were fast extracted from the CSC to enable mass measurements of very short-lived fragments with the MR-TOF-MS. The achievement of this goal was successfully demonstrated with the mass measurement of {sup 220}Ra ions with a half-life of 17.9 ms and 11 detected events. The mass measurements of the isobars {sup 211}Fr, {sup 211}Po and {sup 211}Rn have clearly demonstrated the scientific potential of the MR-TOF-MS for the investigation of exotic nuclei and the power of the data analysis system. Difficult measurements with overlapping mass distributions with only a few counts in the measured spectra were the challenge for the new data analysis method based on the maximum likelihood method. The drifts during the measurements were corrected with the developed time-resolved calibration method. After the improvements of the setup as a consequence of

  9. Radiation characteristics of GD-2 fuel

    International Nuclear Information System (INIS)

    Chrapciak, V.

    2008-01-01

    The assembly WWER-440 type Gd-2 has radial profile of enrichment and has 6 pins with Gd 2 O 3 . The maximal enrichment is 4.4%. Some analyses are done for assembly with flat enrichment (4.4%) and without Gd 2 O 3 . In this article are compared some characteristics (decay heat, some nuclide concentration, photon and gamma sources) for real Gd-2 assembly and for flat 4.4% assembly. The TRITON module (in SCALE 5.1) was used. (Author)

  10. Radiational and energetic characteristics of diatomic molecules (data base)

    International Nuclear Information System (INIS)

    Kuznetsova, L.A.; Pazyuk, E.A.; Stolyarov, A.V.

    1993-01-01

    Data base on radiational and energetic characteristics of diatomic molecules was created. The base consists of two parts: reference system and recommended data system. The reference system contains the information about studies of radiational and energetic parameters of more than 1500 electronic states and 1700 electron transfers for ∼ 350 diatomic molecules and their ions. The base bibliography includes ∼ 3000 publications. 11 refs., 1 figs

  11. Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-related matrix effect; SHRIMP, ID-TIMS, ELA-ICP-MS and oxygen isotope documentation for a series of zircon standards

    Science.gov (United States)

    Black, L.P.; Kamo, S.L.; Allen, C.M.; Davis, D.W.; Aleinikoff, J.N.; Valley, J.W.; Mundil, R.; Campbell, I.H.; Korsch, R.J.; Williams, I.S.; Foudoulis, C.

    2004-01-01

    Precise isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) documentation is given for two new Palaeozoic zircon standards (TEMORA 2 and R33). These data, in combination with results for previously documented standards (AS3, SL13, QGNG and TEMORA 1), provide the basis for a detailed investigation of inconsistencies in 206Pb/238U ages measured by microprobe. Although these ages are normally consistent between any two standards, their relative age offsets are often different from those established by ID-TIMS. This is true for both sensitive high-resolution ion-microprobe (SHRIMP) and excimer laser ablation-inductively coupled plasma-mass spectrometry (ELA-ICP-MS) dating, although the age offsets are in the opposite sense for the two techniques. Various factors have been investigated for possible correlations with age bias, in an attempt to resolve why the accuracy of the method is worse than the indicated precision. Crystallographic orientation, position on the grain-mount and oxygen isotopic composition are unrelated to the bias. There are, however, striking correlations between the 206Pb/238U age offsets and P, Sm and, most particularly, Nd abundances in the zircons. Although these are not believed to be the primary cause of this apparent matrix effect, they indicate that ionisation of 206Pb/238U is influenced, at least in part, by a combination of trace elements. Nd is sufficiently representative of the controlling trace elements that it provides a quantitative means of correcting for the microprobe age bias. This approach has the potential to reduce age biases associated with different techniques, different instrumentation and different standards within and between laboratories. Crown Copyright ?? 2004 Published by Elsevier B.V. All rights reserved.

  12. 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)

  13. N/Z equilibration in damped collisions induced by E/A = 8.5 MeV /sup 58/Ni and /sup 64/Ni on /sup 238/U

    International Nuclear Information System (INIS)

    Planeta, R.; Zhou, S.H.; Kwiatkowski, K.

    1988-01-01

    Nuclide distributions have been measured for damped collision products formed in the reaction of E/A = 8.5 MeV /sup 58/Ni and /sup 64/Ni ions with /sup 238/U. The data demonstrate that in these very asymmetric systems the evolution of the nucleon-exchange process as a function of energy loss depends strongly on the N/Z value of the projectile and the corresponding gradient in the potential-energy surface. Comparison of the data with transport model calculations shows qualitative agreement with the N and Z centroids, variances, and correlation coefficients. However, absolute discrepancies exist which suggest the need for improvement in the model

  14. Determination of uranium isotopes ({sup 235}U, {sup 238}U) and trace elements (Cd, Pb, Cu and As) in bottled drinking water by Icp-SFMS; Determinacion de isotopos de uranio ({sup 235}U, {sup 238}U) y elementos traza (Cd, Pb, Cu y As) en agua embotellada para beber por ICP-SFMS

    Energy Technology Data Exchange (ETDEWEB)

    Lara A, N.; Hernandez M, H.; Romero G, E. T.; Kuri de la C, A.; Perez B, M. A., E-mail: nancy.lara@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2016-09-15

    In the present work we propose an optimized method for the quantification of uranium isotopes ({sup 235}U, 2{sup 38}U) and the elements Cd, Pb, Cu and As in bottled water for drinking at trace levels of concentration. Based on the multi-element detection capability, the high sensitivity and resolution that the Mass Spectrometry with Magnetic Sector with Inductively Coupled Plasma Source (Icp-SFMS) technique offers; the high, medium and low resolution analysis conditions for the elements under study were established and optimized using and Element 2/Xr equipment and the 23 multi-elemental Certified Reference Material (CRM). The analysis method was validated using the standard reference material Nist 1643d and CRM mono-elemental s as external standards for the quantification of the analytes. Samples, targets and CRM were acidified with 2% of HNO{sub 3} and analyzed without pretreatment under the established analysis conditions. The results obtained show concentrations of {sup 235}U, {sup 238}U, {sup 111}Cd, {sup 208}Pb, {sup 63}Cu and {sup 75}As in the range of μg L{sup -1}, the linearity obtained from the calibration curves for each element has correlation coefficients < 0.99 in all cases, the accuracy of the method in terms of percent relative standard deviation (RSD %) was less than 5%, the mean recovery rate of Nist 1643d ranged from 96.46% to 101.12%. The optimization of the method guarantees the stability and calibration of the equipment throughout the analysis, as well as the ability to resolve interferences. In conclusion, the method proposed using Icp-SFMS offers the advantages of being fast and simple for the multi-elemental analysis in water at trace levels, with low limits of quantification and detection, with good linearity, accuracy, precision and reproducibility to a degree of reliability of 95%. (Author)

  15. [Characteristics of infrared radiation of meridians and acupoints].

    Science.gov (United States)

    Zheng, Juan-Juan; Shen, Xue-Yong; Zhao, Yi

    2010-10-01

    Infrared radiation temperature and characteristics of infrared spectrum of meridians and acupoints are summarized in this article. The infrared radiant track along the running course of meridians might be a ubiquitous phenomenon of the vital activity. The high temperature bands below the meridian lines at the cuticular layer are often taken as the manifestation of the tract. It could be induced by various stimulations on acupoints with warm-needling as the best causative method. High temperature and low resistance are considered as 2 features of the acupoint zone. The adenosine-triphosphate energy metabolism of the acupoint zone is higher than the non-point zone, which indicates that essential physiological and pathological information are carried by infrared radiation temperature of acupoint and infrared spectrum of acupoint. However, it is realized that study on characteristics of infrared radiation only is far from enough to reveal the essence of meridians and acupoints. And much still remains to be done in strengthening basic studies of characteristics of infrared radiation, structure pattern of meridians and acupoints as well as volt-ampere characteristics.

  16. Application of activation technique for mass and nuclear charge distributions studies of 3 Mev and 14 Mev neutrons induced 238-U(n,f) and 232-Th(n,f)

    International Nuclear Information System (INIS)

    Embarch, K.

    1988-01-01

    Fission product cumulative and independent yields were determined for 238-U(n,f) and 232-Th(n,f) reactions with essentially monoenergetic neutrons of 3 and 14 Mev. Fission product activities were measured by Ge(Li)γ-ray spectrometry of irradiated 238-U and 232-Th foils. These experiments allowed us to measure a great number of cumulative yields and to obtain the fission product mass distributions corresponding to the studied reactions mentioned above. The mass distributions were completely interpreted by nucleon shell effects and proton even-odd effects. The independent yield measurements are sometimes not possible using the activation technique because of the fission fragment decay data. The values which can not be measured were determined using the measured mass yields and a prediction systematic of fractional independent yield. The results allowed us to obtain the nuclear charge distributions and to estimate proton even-odd effect corresponding values. This effect decreases when the excitation energy of the fissioning nucleus increases, this shows the importance of this parameter in the viscosity study of the nuclear matter. In conclusion, the shell effects observed in the mass distributions show that the static aspect of the fission mechanism plays a great role during the fission process, and observed proton even-odd effects act for a weak nuclear viscosity. 54 refs., 27 figs., 25 tabs

  17. 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.

  18. 235U, 238U, 232Th, 40K and 137Cs activity concentrations in marine sediments along the northern coast of Oman Sea using high-resolution gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Zare, Mohammad Reza; Mostajaboddavati, Mojtaba; Kamali, Mahdi; Abdi, Mohammad Reza; Mortazavi, Mohammad Seddigh

    2012-01-01

    The natural radioactivity levels in sediment samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz canyon to Goatr seaport, as the first time has been determined. The results of measurements will serve as background reference level for Oman Sea coastlines. Sediments from 36 coastal and near shore locations were collected for analysis. Analysis on the collected samples were carried out to determine 235 U, 238 U, 232 Th, 40 K and 137 Cs using two high purity germanium detectors with 38.5% and 55% relative efficiencies. The concentration of 235 U, 238 U, 232 Th, 40 K and 137 Cs in sediment samples ranged between 1.01 and 2.87 Bq/kg, 11.83 and 22.68 Bq/kg, 10.7 and 25.02 Bq/kg, 222.89 and 535.07 Bq/kg and 0.14 and 2.8 Bq/kg, respectively. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose.

  19. Determination of the concentration of 238U, 234U, 232Th, 228Th, 228Ra, 226Ra and 210Pb in the feces of workers from a mining company of niobium and their families

    International Nuclear Information System (INIS)

    Oliveira, Roges de; Lopes, Ricardo T.; Melo, Dunstana R.; Juliao, Ligia M.Q.C.

    2005-01-01

    The object of this study consists of an open mine from which Niobium ore (pyrochlore) is extracted and a metallurgy company, where Fe-Nb alloys are produced for export. For geological reasons, the main ore is associated to natural radionuclides U and Th, and its decay products. The concentration of 234 U, 238 U, 232 Th, 226 Ra and 228 Ra, 228 Th, including 210 Pb in fecal excretion of 12:0 am, 29 workers and 13 family members were determined. The technique employed for the determination of the elements was the sequential method of radiochemical separation, followed by alpha spectrometry and counting α and β in proportional detector. Statistically significant difference was observed in the concentration of 234 U and 238 U, in feces samples, among the group of mining workers and family members; as well as for 232 Th in the feces of workers of crushing and metallurgy groups when compared with the Family Group. No statistically significant difference was detected at a concentration of 226 Ra, 228 Ra and 210 Pb, in feces of any group of workers of the installation in relation to the family group

  20. 47 CFR 73.160 - Vertical plane radiation characteristics, f(θ).

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Vertical plane radiation characteristics, f(Î... SERVICES RADIO BROADCAST SERVICES AM Broadcast Stations § 73.160 Vertical plane radiation characteristics, f(θ). (a) The vertical plane radiation characteristics show the relative field being radiated at a...

  1. Reference neutron radiations. Part 1: Characteristics and methods of production

    International Nuclear Information System (INIS)

    2001-01-01

    ISO 8529 consists of the following parts, under the general title Reference neutron radiations: Part 1: Characteristics and methods of production; Part 2: Calibration fundamentals of radiation protection devices related to the basic quantities characterizing the radiation field; Part 3: Calibration of area and personal dosimeters and determination of response as a function of energy and angle of incidence. This Part 1. of ISO 8529 specifies the reference neutron radiations, in the energy range from thermal up to 20 MeV, for calibrating neutron-measuring devices used for radiation protection purposes and for determining their response as a function of neutron energy. Reference radiations are given for neutron fluence rates of up to 1x10 9 m 2 s-1 , corresponding, at a neutron energy of 1 MeV, to dose-equivalent rates of up to 100 mSv h -1 . This part of ISO 8529 is concerned only with the methods of producing and characterizing the neutron reference radiations. The procedures for applying these radiations for calibrations are described in ISO 8529-2 and ISO 8529-3. The reference radiations specified are the following: neutrons from radionuclide sources, including neutrons from sources in a moderator; neutrons produced by nuclear reactions with charged particles from accelerators; neutrons from reactors. In view of the methods of production and use of them, these reference radiations are divided, for the purposes of this part of ISO 8529, into the following two separate sections. In clause 4, radionuclide neutron sources with wide spectra are specified for the calibration of neutron measuring devices. These sources should be used by laboratories engaged in the routine calibration of neutron-measuring devices, the particular design of which has already been type tested. In clause 5, accelerator-produced monoenergetic neutrons and reactor-produced neutrons with wide or quasi monoenergetic spectra are specified for determining the response of neutron-measuring devices

  2. Radiation Characteristics of the Cavity Backed Antenna in Conducting Cone

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A technique using finite element and boundary integral method (FE-BI) and reciprocity theorem is presented to analyze the radiation characteristics of cavity backed antenna mounted on a conducting cone. The electric fields inside the cavity and on the aperture are obtained using finite element and boundary integral method. The far-field characteristic of the antenna is computed using reciprocity theorem. The paper begins with a general description of the method. An application of this method is given and the numerical result is compared with the experimental result.

  3. The effect of ionizing radiation on analog characteristics of MOSFET

    International Nuclear Information System (INIS)

    Ren Diyuan; Yu Xuefeng; Lu Wu; Gao Wenyu; Fan Long; Zhang Guoqiang; Yan Rongliang

    1994-01-01

    The effects of 60 Co γ-ray on the linearity and output characteristics of MOSFETs were investigated. The relations of oxide-trapped charge and Si/SiO 2 interface state density to the decrease of mobility μ-bar and transconductance g m , and the shift of the output curves for both P-MOSFETs and N-MOSFETs were qualitatively described. It was shown that degradation of analog characteristics, for P-MOSFETs, resulted from both oxide-trapped charge and interface state, but the degradation for N-MOSFETs was mainly due to the increase of radiation induced Si-SiO 2 interface state density

  4. Studies on the radiation absorption characteristics of various rocks

    International Nuclear Information System (INIS)

    Rahman, K.N.; Abdullah, S.A.; Gazzaz, M.A.

    1984-05-01

    Radiation absorption characteristics of nine different rocks, namely, ferrugenous quartz, metabasalt, larvikite, coarse grained diorite, coarse grained granite, coarse grained alkali granite, marble, quartz mica schist, and metamorphosed rock are studied. The rocks were collected from Jeddah, Makkah, Mina and Taif areas. Special attention was given on the availability, compactness, physical formation and uniform composition in selecting the rocks. The rocks were identified by optical method and their elemental composition determined by chemical analysis. The data were used to calculate the effective atomic numbers, half value layers mass and linear attenuation coefficients. The half value layers and the linear attenuation coefficientsof these rocks were determined experimentally using Am-241, Cs-137,and Co-60 sources. The results are compared with those obtained by theoretical calculations and agrre within 10%. Most of the rocks show much higher radiation attenuation characteristics than the standard concrete. Rocks containing higher percentage of Fe, Ca, Ti, and Mn show much higher radiation absorption characteristics than concrete. Only granites are found to be almost equivalent to concrete. 12 Ref

  5. A RADIATION TRANSFER SOLVER FOR ATHENA USING SHORT CHARACTERISTICS

    International Nuclear Information System (INIS)

    Davis, Shane W.; Stone, James M.; Jiang Yanfei

    2012-01-01

    We describe the implementation of a module for the Athena magnetohydrodynamics (MHD) code that solves the time-independent, multi-frequency radiative transfer (RT) equation on multidimensional Cartesian simulation domains, including scattering and non-local thermodynamic equilibrium (LTE) effects. The module is based on well known and well tested algorithms developed for modeling stellar atmospheres, including the method of short characteristics to solve the RT equation, accelerated Lambda iteration to handle scattering and non-LTE effects, and parallelization via domain decomposition. The module serves several purposes: it can be used to generate spectra and images, to compute a variable Eddington tensor (VET) for full radiation MHD simulations, and to calculate the heating and cooling source terms in the MHD equations in flows where radiation pressure is small compared with gas pressure. For the latter case, the module is combined with the standard MHD integrators using operator splitting: we describe this approach in detail, including a new constraint on the time step for stability due to radiation diffusion modes. Implementation of the VET method for radiation pressure dominated flows is described in a companion paper. We present results from a suite of test problems for both the RT solver itself and for dynamical problems that include radiative heating and cooling. These tests demonstrate that the radiative transfer solution is accurate and confirm that the operator split method is stable, convergent, and efficient for problems of interest. We demonstrate there is no need to adopt ad hoc assumptions of questionable accuracy to solve RT problems in concert with MHD: the computational cost for our general-purpose module for simple (e.g., LTE gray) problems can be comparable to or less than a single time step of Athena's MHD integrators, and only few times more expensive than that for more general (non-LTE) problems.

  6. The fission cross sections of 230Th, 232Th, 233U, 234U, 236U, 238U, 237Np, 239Pu and 242Pu relative 235U at 14.74 MeV neutron energy

    International Nuclear Information System (INIS)

    Meadows, J.W.

    1986-12-01

    The measurement of the fission cross section ratios of nine isotopes relative to 235 U at an average neutron energy of 14.74 MeV is described with particular attention to the determination of corrections and to sources of error. The results are compared to ENDF/B-V and to other measurements of the past decade. The ratio of the neutron induced fission cross section for these isotopes to the fission cross section for 235 U are: 230 Th - 0.290 +- 1.9%; 232 Th - 0.191 +- 1.9%; 233 U - 1.132 +- 0.7%; 234 U - 0.998 +- 1.0%; 236 U - 0.791 +- 1.1%; 238 U - 0.587 +- 1.1%; 237 Np - 1.060 +- 1.4%; 239 Pu - 1.152 +- 1.1%; 242 Pu - 0.967 +- 1.0%. 40 refs., 11 tabs., 9 figs

  7. Neutron induced fission cross section ratios for /sup 232/Th, /sup 235,238/U, /sup 237/Np, and /sup 239/Pu from 1 to 400 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Lisowski, P.W.; Ullmann, J.L.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

    1988-01-01

    Time-of-flight measurements of neutron induced fission cross section ratios for /sup 232/Th, /sup 235,238/U, /sup 237/Np, and /sup 239/Pu, were performed using the WNR high intensity spallation neutron source located at Los Alamos National Laboratory. A multiple-plate gas ionization chamber located at a 20-m flight path was used to simultaneously measure the fission rate for all samples over the energy range from 1 to 400 MeV. Because the measurements were made with nearly identical neutron fluxes, we were able to cancel many systematic uncertainties present in previous measurements. This allows us to resolve discrepancies among different data sets. In addition, these are the first neutron-induced fission cross section values for most of the nuclei at energies above 30 MeV. 8 refs., 3 figs.

  8. Measurement of the cross sections for the 238U(n,2n) and 232Th(n,2n) reactions in the 13.5 - 14.8 MeV energy range

    International Nuclear Information System (INIS)

    Raics, P.; Nagy, S.; Daroczy, S.; Kornilov, N.V.

    1990-10-01

    (n,2n) reaction cross sections have been determined for 238 U and 232 Th by using the activation method. Neutrons were produced in D-T reaction by bombarding a TiT target with analyzed deuteron beam from a Cockcroft-Walton accelerator. Neutron energy was varied by changing the emission angle to the deuteron beam. The activities of the 237 U and 231 Th residual nuclei were measured by a Ge(Li) and a HP Ge gamma-spectrometer, respectively. Several standard reactions were used for the determination of the neutron flux density. An overall precision of 3.5 - 4.5% was estimated and a 1.4 - 3.5% reproducibility was achieved. Comparison of the recent results to literature data and a brief analysis of the monitor reactions are given. (author). 48 refs, 3 figs, 7 tabs

  9. Study of the continuum production between 2.1 and 2.7 GeV/c2 and J/Ψ in the 32S+238U → μ μ +X collisions at 200 GeV per nucleon

    International Nuclear Information System (INIS)

    Staley, F.

    1989-01-01

    Quantum chromodynamics predicts a phase transition of nuclear matter at high energy density, or high temperature, to a quark gluon plasma (QGP). One of the possible signal of the QGP is the J/Ψ suppression. Since transverse energy is proportional to energy density, transverse energy and transverse momentum cross section distributions give an accurate study of the J/Ψ suppression. Experimentally we compare the J/Ψ production to the continuum production versus transverse energy produced in 32 S- 238 U collisions. Our results are compared to the predictions of the quark gluon plasma and absorption models. Nuclear absorption cannot explain the 50% suppression of J/Ψ that we obtain. Dense pion gas and gluon multiscattering in the initial state explain the suppression and its transverse momentum dependence; however the accuracy of our results does not allow us to discriminate between models [fr

  10. Characteristics of radiation field in living environment, 2

    International Nuclear Information System (INIS)

    Nagaoka, Toshi; Sakamoto, Ryuichi; Tsutsumi, Masahiro; Saito, Kimiaki; Moriuchi, Shigeru

    1990-01-01

    A series of environmental radiation survey was carried out on train lines within Tokyo metropolitan area to clarify the characteristics of radiation field in living environment. Eleven JR, 18 private and 10 subway lines were surveyed, which cover 97% of whole train lines in Tokyo district in terms of annual number of passengers. The characteristics of environmental radiation field on train lines were discussed. The mean absorbed dose rate in air due to γ-rays on the subway lines was higher than those on the JR and private lines. It is due to the difference in the radioactivity concentration and the distribution of surrounding materials as the γ-ray sources. On the other hand, the mean dose rate due to cosmic-rays on the subway lines was lower than those on the JR and private lines. It is due to the shielding effect of the upper materials such as soil or building materials of tunnels. The mean dose rates for the JR, private and subway lines were calculated using these obtained data. Though the ratio of mean dose rate of γ-rays to that of cosmic-rays for the subway lines was different from those for the JR and private lines, the sum of γ- and cosmic-ray dose rates for the JR, private and subway lines were comparable, 40∼50 nGy/h for any of them. These data will be useful for a precise and realistic evaluation of collective dose, considering the life style of the public and the variation characteristics of environmental radiation. (author)

  11. Potential human health risk by metal(loid)s, 234,238U and 210Po due to consumption of fish from the "Luis L. Leon" Reservoir (Northern México).

    Science.gov (United States)

    Luna-Porres, Mayra Y; Rodríguez-Villa, Marco A; Herrera-Peraza, Eduardo F; Renteria-Villalobos, Marusia; Montero-Cabrera, María E

    2014-06-25

    Concentrations of As, Cu, Fe, Hg, Pb and Zn and activity concentrations from 234,238U and 210Po in water, fillet, liver and gills were determined in three stocked fish species from the Luis L. Leon reservoir, located in Northern Mexico. The considered species were Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus. 238U and 234U activity concentration (AC) in fillet samples showed values of 0.007-0.014 and 0.01-0.02 Bq∙kg-1 wet weight (ww), respectively. Liver samples for L. cyanellus, C. carpio and I. furcatus present 210Po AC of 1.16-3.26, 0.70-1.13 and 0.93-1.37 Bq∙kg-1 ww. Arsenic, mercury and lead concentration intervals in fillet samples were 0.13-0.39, 0.005-0.126 and 0.009-0.08 mg∙kg-1 ww, respectively, while in gill samples they were 0.11-0.43, 0.002-0.039 and 0.02-0.26 mg∙kg-1 ww. The elemental Bioaccumulation Factor (BAF) for fish tissues with respect to their concentrations in water was determined. L. cyanellus showed the highest BAF values for As and total U, being BAFAs = 37 and 40 L∙kg-1 in fillet and gills, respectively, and BAFU total = 1.5 L∙kg-1 in fillet. I. furcatus showed the highest BAF values for Hg and Pb, being BAFHg = 40 and 13 L∙kg-1 in fillet and gills, and BAFPb = 6.5 and 22 L∙kg-1 in fillet and gills, respectively. Some metal(loid) concentrations are slightly higher than European regulations for fish fillets. The difference in concentrations of metal(loid)s in fillet among the studied species is probably due to their differences in diet and habitat.

  12. Tracing of natural radionuclides mobility in deep sedimentary environment using radioactive (234U/238U) disequilibria: application to the Mesozoic formations of the Eastern part of the Paris Basin

    International Nuclear Information System (INIS)

    Deschamps, P.

    2003-11-01

    This thesis forms part of the geological investigations undertaken by the French agency for nuclear waste management, ANDRA, around the Meuse/Haute-Marne Underground Research Laboratory (URL) located in the Eastern part of the Paris Basin in order to evaluate the feasibility of high-level radioactive waste repository in deep argilite formations. The aim of the study is to examine the radionuclide migration in the deep Callovo-Oxfordian target argilite layer and its surrounding low- permeability Bathonian and Oxfordian limestone formations in order to assess the long term confining capacities of the sedimentary series. This study is based on measurement of radioactive disequilibria within U-series by Multiple- Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The high precision and accuracy achieved allowed to demonstrate the 234 U/ 238 U radioactive equilibrium in the Callovo-Oxfordian argilites. This result shows the uranium immobility in the target formation and provides a strong evidence for the current chemical stability and closure of the system for uranium and most probably for the other actinides. This is a fundamental result with respect to the problematic of disposal of high level radioactive waste in deep geological formation since it provides a in situ indication of the confining capacities of the clayey target formation in the current settings. Conversely, ( 234 U/ 238 U) disequilibria are systematically observed within zones, located in the surrounding carbonate formations, that are characterized by pressure dissolution structures (stylolites or dissolution seams). These disequilibria provide evidence for a discrete uranium relocation during the last two million years in the vicinity of stylolitic structures. This is a surprising result since it is generally supposed that these deep, low permeability, compact formations behave as closed system at the time scale of the U-series. (author)

  13. Application of Monte Carlo method in determination of secondary characteristic X radiation in XFA

    International Nuclear Information System (INIS)

    Roubicek, P.

    1982-01-01

    Secondary characteristic radiation is excited by primary radiation from the X-ray tube and by secondary radiation of other elements so that excitations of several orders result. The Monte Carlo method was used to consider all these possibilities and the resulting flux of characteristic radiation was simulated for samples of silicate raw materials. A comparison of the results of these computations with experiments allows to determine the effect of sample preparation on the characteristic radiation flux. (M.D.)

  14. Natural Radiation in byproducts of the production of phosphoric acid

    International Nuclear Information System (INIS)

    Silveira, Marcilei A. Guazzelli da; Cardoso, L.L.; Medina, N.H.

    2014-01-01

    Natural radiation is the largest source of radiation exposure to which man is subject. It is formed basically by cosmic radiation and the radionuclides present in the Earth crust, as 40 K and the elements of the decay series of 232 Th and 238 U. Phosphate ores, which constitutes the raw material for the production of phosphoric acid, have a high rate of natural radiation from the decay series of 232 Th and 238 U. Phosphogypsum, which is naturally radioactivity, is a by-product of the production of phosphoric acid by the wet method. For each ton of phosphoric acid it is produced about 4.5 tons of phosphogypsum. This work presents the analysis of samples collected in all stages of the manufacturing process of phosphoric acid, which generates the phosphogypsum. Gamma-ray spectrometry was used to measure the concentration of the elements of the decay series of 232 Th and 238 U. All analyzed samples showed a high concentration of radionuclides, promoting the need for further steps in the process in order to reduce the presence of such radionuclides in the phosphogypsum. The results indicate the radionuclide 238 U has higher contribution in some samples of the intermediate stages of the process. All samples exceeded the international average range of human exposure to terrestrial gamma radiation, which is 0.3 to 1.0 mSv/year. (author)

  15. Gamma radiation influence on technological characteristics of wheat flour

    International Nuclear Information System (INIS)

    Teixeira, Christian A.H.M.; Inamura, Patricia Y.; Uehara, Vanessa B.; Mastro, Nelida L.d.

    2012-01-01

    This study aimed at determining the influence of gamma radiation on technological characteristics of wheat (Triticum sativum) flour and physical properties of pan breads made with this flour. The bread formulation included wheat flour, water, milk, salt, sugar, yeast and butter. The α-amylase activity of wheat flour irradiated with 1, 3 and 9 kGy in a Gammacell 220 (AECL), one day, five days and one month after irradiation was evaluated. Deformation force, height and weight of breads prepared with the irradiated flour were also determined. The enzymatic activity increased—reduction of falling number time—as radiation dose increased, their values being 397 s (0 kGy), 388 s (1 kGy), 343 s (3 kGy) and 293 s (9 kGy) respectively, remaining almost constant over the period of one month. Pan breads prepared with irradiated wheat flour showed increased weight. Texture analysis showed that bread made of irradiated flour presented an increase in maximum deformation force. The results indicate that wheat flour ionizing radiation processing may confer increased enzymatic activity on bread making and depending on the irradiation dose, an increase in weight, height and deformation force parameters of pan breads made of it. - Highlights: ► We study the influence of gamma radiation on wheat flour and properties of breads. ► Falling number decreased with radiation remaining almost constant up to one month. ► Ionizing radiation may confer an increase in texture parameters, weight and height on the bread.

  16. Research on Radiation Characteristic of Plasma Antenna through FDTD Method

    Directory of Open Access Journals (Sweden)

    Jianming Zhou

    2014-01-01

    Full Text Available The radiation characteristic of plasma antenna is investigated by using the finite-difference time-domain (FDTD approach in this paper. Through using FDTD method, we study the propagation of electromagnetic wave in free space in stretched coordinate. And the iterative equations of Maxwell equation are derived. In order to validate the correctness of this method, we simulate the process of electromagnetic wave propagating in free space. Results show that electromagnetic wave spreads out around the signal source and can be absorbed by the perfectly matched layer (PML. Otherwise, we study the propagation of electromagnetic wave in plasma by using the Boltzmann-Maxwell theory. In order to verify this theory, the whole process of electromagnetic wave propagating in plasma under one-dimension case is simulated. Results show that Boltzmann-Maxwell theory can be used to explain the phenomenon of electromagnetic wave propagating in plasma. Finally, the two-dimensional simulation model of plasma antenna is established under the cylindrical coordinate. And the near-field and far-field radiation pattern of plasma antenna are obtained. The experiments show that the variation of electron density can introduce the change of radiation characteristic.

  17. Research on radiation characteristic of plasma antenna through FDTD method.

    Science.gov (United States)

    Zhou, Jianming; Fang, Jingjing; Lu, Qiuyuan; Liu, Fan

    2014-01-01

    The radiation characteristic of plasma antenna is investigated by using the finite-difference time-domain (FDTD) approach in this paper. Through using FDTD method, we study the propagation of electromagnetic wave in free space in stretched coordinate. And the iterative equations of Maxwell equation are derived. In order to validate the correctness of this method, we simulate the process of electromagnetic wave propagating in free space. Results show that electromagnetic wave spreads out around the signal source and can be absorbed by the perfectly matched layer (PML). Otherwise, we study the propagation of electromagnetic wave in plasma by using the Boltzmann-Maxwell theory. In order to verify this theory, the whole process of electromagnetic wave propagating in plasma under one-dimension case is simulated. Results show that Boltzmann-Maxwell theory can be used to explain the phenomenon of electromagnetic wave propagating in plasma. Finally, the two-dimensional simulation model of plasma antenna is established under the cylindrical coordinate. And the near-field and far-field radiation pattern of plasma antenna are obtained. The experiments show that the variation of electron density can introduce the change of radiation characteristic.

  18. Radiation resistance characteristics of optical communication system for single mode

    International Nuclear Information System (INIS)

    Ohe, Masamoto; Chigusa, Yoshiki; Kyodo, Tomohisa; Tanaka, Gohtaro; Watanabe, Hajime; Okamoto, Shin-ichi; Yamamoto, Takao.

    1988-01-01

    Optical communication has been utilized also for nuclear power stations and fuel reporocessing plants. As the sufficient safety countermeasures are required there, the amount of information becomes enormous, therefore, optical communication, by which the required space is expected to be reduced, becomes more important. Also in the application to submarine cables, attention must be paid to the radiation resistance as there are the effects of potassium contained in large amount in seawater and uranium deposits in sea bottom. Therefore, the reliability of the components of optical communication systems against radiation becomes a problem. In this study, single mode optical fibers and transmission and receipt modules were selected, and high dose rate irradiation supposing the case of using in a cell and low dose rate, long time irradiation supposing the case of submarine cables were carried out to evaluate the radiation resistance characteristics. The fibers tested were SiO 2 core/F-SiO 2 clad type and GeO 2 -SiO 2 core/SiO 2 clad type. The characteristics of increasing loss in irradiation and restoration after irradiation of the former type were superior to those of the latter type. The output of a receipt module was normal during irradiation, and the output power of a transmission module decreases, but other problems did not arise. (K.I.)

  19. Tracing of natural radionuclides mobility in deep sedimentary environment using radioactive ({sup 234}U/{sup 238}U) disequilibria: application to the Mesozoic formations of the Eastern part of the Paris Basin; Tracage de la mobilite des radionucleides naturels en milieu sedimentaire profond a l'aide des desequilibres radioactifs ({sup 234}U/{sup 238}U): application aux formations mesozoiques de l'est du Bassin de Paris

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, P

    2003-11-01

    This thesis forms part of the geological investigations undertaken by the French agency for nuclear waste management, ANDRA, around the Meuse/Haute-Marne Underground Research Laboratory (URL) located in the Eastern part of the Paris Basin in order to evaluate the feasibility of high-level radioactive waste repository in deep argilite formations. The aim of the study is to examine the radionuclide migration in the deep Callovo-Oxfordian target argilite layer and its surrounding low- permeability Bathonian and Oxfordian limestone formations in order to assess the long term confining capacities of the sedimentary series. This study is based on measurement of radioactive disequilibria within U-series by Multiple- Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The high precision and accuracy achieved allowed to demonstrate the {sup 234}U/{sup 238}U radioactive equilibrium in the Callovo-Oxfordian argilites. This result shows the uranium immobility in the target formation and provides a strong evidence for the current chemical stability and closure of the system for uranium and most probably for the other actinides. This is a fundamental result with respect to the problematic of disposal of high level radioactive waste in deep geological formation since it provides a in situ indication of the confining capacities of the clayey target formation in the current settings. Conversely, ({sup 234}U/{sup 238}U) disequilibria are systematically observed within zones, located in the surrounding carbonate formations, that are characterized by pressure dissolution structures (stylolites or dissolution seams). These disequilibria provide evidence for a discrete uranium relocation during the last two million years in the vicinity of stylolitic structures. This is a surprising result since it is generally supposed that these deep, low permeability, compact formations behave as closed system at the time scale of the U-series. (author)

  20. Tracing of natural radionuclides mobility in deep sedimentary environment using radioactive ({sup 234}U/{sup 238}U) disequilibria: application to the Mesozoic formations of the Eastern part of the Paris Basin; Tracage de la mobilite des radionucleides naturels en milieu sedimentaire profond a l'aide des desequilibres radioactifs ({sup 234}U/{sup 238}U): application aux formations mesozoiques de l'est du Bassin de Paris

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, P

    2003-11-01

    This thesis forms part of the geological investigations undertaken by the French agency for nuclear waste management, ANDRA, around the Meuse/Haute-Marne Underground Research Laboratory (URL) located in the Eastern part of the Paris Basin in order to evaluate the feasibility of high-level radioactive waste repository in deep argilite formations. The aim of the study is to examine the radionuclide migration in the deep Callovo-Oxfordian target argilite layer and its surrounding low- permeability Bathonian and Oxfordian limestone formations in order to assess the long term confining capacities of the sedimentary series. This study is based on measurement of radioactive disequilibria within U-series by Multiple- Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The high precision and accuracy achieved allowed to demonstrate the {sup 234}U/{sup 238}U radioactive equilibrium in the Callovo-Oxfordian argilites. This result shows the uranium immobility in the target formation and provides a strong evidence for the current chemical stability and closure of the system for uranium and most probably for the other actinides. This is a fundamental result with respect to the problematic of disposal of high level radioactive waste in deep geological formation since it provides a in situ indication of the confining capacities of the clayey target formation in the current settings. Conversely, ({sup 234}U/{sup 238}U) disequilibria are systematically observed within zones, located in the surrounding carbonate formations, that are characterized by pressure dissolution structures (stylolites or dissolution seams). These disequilibria provide evidence for a discrete uranium relocation during the last two million years in the vicinity of stylolitic structures. This is a surprising result since it is generally supposed that these deep, low permeability, compact formations behave as closed system at the time scale of the U-series. (author)

  1. Wave Characteristics of Temperature Inversion Process of Nighttime Radiation,

    Science.gov (United States)

    1983-12-09

    CHARACTERISTICS OF TEMPERATURE INVERSION PROCESS OF NIGHTTIME RADIATION By: Zhou Mingyu and Zhang ¥i English pages: 8 Source: Kexue Tongbao, 1982, pp. 156...lJournal of Meteorology], 39 (1981), 1:70-81. 3. Drazin, P. G., J. Fluid. Mech., 4 (1958), 214-224. 4. Zhou Mingyu et al., QIXIANG XUEBAO, 38 (1980), 3: 250...258. 5. Emnanuel, C. B., B-L. Meteor., 5(1973), N(1/2)8 19-27. 6. Zhou Mingyu et al., J. Acoust. Soc., A. m., 68 (1980), 1: 303-308. 8 I iI

  2. Characteristics of natural background external radiation and effective dose equivalent

    International Nuclear Information System (INIS)

    Fujimoto, Kenzo

    1989-01-01

    The two sources of natural radiation - cosmic rays and primordial radionuclides - are described. The factors affecting radiation doses received from natural radiation and the calculation of effective dose equivalent due to natural radiation are discussed. 10 figs., 3 tabs

  3. Production of residual nuclei in the spallation of 238U by 1 GeV protons and 2 GeV deuterons, measured in inverse kinematics

    International Nuclear Information System (INIS)

    Bernas, M.; Casarejos, E.; Pereira, J.

    2002-09-01

    In this paper, we report on the first systematic study of nuclide production in isotopic chains from nitrogen (Z=7) to uranium (Z=92). In the second section, we present some characteristics of the experimental set up and the analysis techniques. In the third and in the forth part, we report on the obtained cross sections and kinematical properties of the studied nuclei, respectively. In the last section, we discuss the results and compare them to data obtained previously with conventional techniques. (orig.)

  4. Gamma radiation influence on technological characteristics of wheat flour

    Science.gov (United States)

    Teixeira, Christian A. H. M.; Inamura, Patricia Y.; Uehara, Vanessa B.; Mastro, Nelida L. d.

    2012-08-01

    This study aimed at determining the influence of gamma radiation on technological characteristics of wheat (Triticum sativum) flour and physical properties of pan breads made with this flour. The bread formulation included wheat flour, water, milk, salt, sugar, yeast and butter. The α-amylase activity of wheat flour irradiated with 1, 3 and 9 kGy in a Gammacell 220 (AECL), one day, five days and one month after irradiation was evaluated. Deformation force, height and weight of breads prepared with the irradiated flour were also determined. The enzymatic activity increased—reduction of falling number time—as radiation dose increased, their values being 397 s (0 kGy), 388 s (1 kGy), 343 s (3 kGy) and 293 s (9 kGy) respectively, remaining almost constant over the period of one month. Pan breads prepared with irradiated wheat flour showed increased weight. Texture analysis showed that bread made of irradiated flour presented an increase in maximum deformation force. The results indicate that wheat flour ionizing radiation processing may confer increased enzymatic activity on bread making and depending on the irradiation dose, an increase in weight, height and deformation force parameters of pan breads made of it.

  5. Influence of the cosmic-ray induced fission tracks on the fission track of extraterrestric minerals via the 238U spontaneous fission

    International Nuclear Information System (INIS)

    Damm, G.; Thiel, K.

    1977-01-01

    The age determined by counting fission tracks of lunar and meteorite materials is obviously falsified by additional fission track parts not to be accounted for by the spontaneous fission of uranium 238. For this p and n induced fissions of U, Th and other hreavy elements through the cosmic radiation come into consideration. In order to determine the possible part of such interference factors, a simulation experiment at the proton synchrocycloton (CERN, Geneva) has been carried out and independently of this, the production rates for the p and n induced U, Th, Bi, Pb and Au in the surface-near regolith layers of the moon were calculated. It could be seen that the irradiation age as well as the spacial distribution of the heavy metals in the samples to be dated must be considered. (RB) [de

  6. U-series radioactive disequilibria 238U-230Th-226Ra: discussions on sources and processes responsible for volcanism of the Andean cordillera and on the deglaciation in Iceland

    International Nuclear Information System (INIS)

    Chmeleff, J.

    2005-10-01

    Thanks to precise analyses of uranium series radioactive disequilibria, permitted by improvements of mass spectrometry data acquisition and optimization of chemistry, two questions were tackled and answers about the periods of glaciation in Iceland and the petrogenesis of Andean lavas were proposed. Two methods were used to date lava flows from the Reykjanes peninsula and the island of Heimaey, in Iceland, directly linked to the periods of deglaciation or reheating around the last ice age. An original method based on the use of segregation veins present in the lava flows has been developed. Thanks to the formation of this particular geological object this methods permits to be freed from xeno-crystals when using the internal isochron method in the 238 U- 230 Th system. Using this method some constraints are brought both on the quaternary geology of the area of Reykjavik and on the age of the end of the Wurm glaciation on Heirnaey. In parallel, due to the homogeneity of the historical and Holocene lavas of the Reykjanes peninsula, regarding the ( 230 Th/ 232 Th) and Th/U ratios, it is possible to derive the ( 230 Th/ 232 Th) ratio in time to determine the age of lava flows installed during the ice age. Thus we confirmed that the magnetic excursion recorded in the Skalamaelifell lava flow is most probably the same one as that of Laschamp-Olby and that at this time (approximately 48.000 years) the Reykjanes peninsula was entirely covered with a glacier. Thanks to this method the extent of the glacier was also constrained by dating of a picritic shield around 22.000 years, thus the peninsula has to be free of any ice cap despite the fact that glaciation is the most intense around this time.Then Andean arc magmas petrogenesis was constrained in time and space. Almost systematic excesses of 226 Ra compared to 230 Th in lavas of austral, southern and northern volcanic zones of the Andes (AVZ, SVZ and NVZ) constrain the ascending time from the source to the surface after

  7. Potential Human Health Risk by Metal(loids, 234,238U and 210Po due to Consumption of Fish from the “Luis L. Leon” Reservoir (Northern México

    Directory of Open Access Journals (Sweden)

    Mayra Y. Luna-Porres

    2014-06-01

    Full Text Available Concentrations of As, Cu, Fe, Hg, Pb and Zn and activity concentrations from 234,238U and 210Po in water, fillet, liver and gills were determined in three stocked fish species from the Luis L. Leon reservoir, located in Northern Mexico. The considered species were Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus. 238U and 234U activity concentration (AC in fillet samples showed values of 0.007–0.014 and 0.01–0.02 Bq∙kg−1 wet weight (ww, respectively. Liver samples for L. cyanellus, C. carpio and I. furcatus present 210Po AC of 1.16–3.26, 0.70–1.13 and 0.93–1.37 Bq∙kg−1 ww. Arsenic, mercury and lead concentration intervals in fillet samples were 0.13–0.39, 0.005–0.126 and 0.009–0.08 mg∙kg−1 ww, respectively, while in gill samples they were 0.11–0.43, 0.002–0.039 and 0.02–0.26 mg∙kg−1 ww. The elemental Bioaccumulation Factor (BAF for fish tissues with respect to their concentrations in water was determined. L. cyanellus showed the highest BAF values for As and total U, being BAFAs = 37 and 40 L∙kg−1 in fillet and gills, respectively, and BAFU total = 1.5 L∙kg−1 in fillet. I. furcatus showed the highest BAF values for Hg and Pb, being BAFHg = 40 and 13 L∙kg−1 in fillet and gills, and BAFPb = 6.5 and 22 L∙kg−1 in fillet and gills, respectively. Some metal(loid concentrations are slightly higher than European regulations for fish fillets. The difference in concentrations of metal(loids in fillet among the studied species is probably due to their differences in diet and habitat.

  8. Potential Human Health Risk by Metal(loid)s, 234,238U and 210Po due to Consumption of Fish from the “Luis L. Leon” Reservoir (Northern México)

    Science.gov (United States)

    Luna-Porres, Mayra Y.; Rodríguez-Villa, Marco A.; Herrera-Peraza, Eduardo F.; Renteria-Villalobos, Marusia; Montero-Cabrera, María E.

    2014-01-01

    Concentrations of As, Cu, Fe, Hg, Pb and Zn and activity concentrations from 234,238U and 210Po in water, fillet, liver and gills were determined in three stocked fish species from the Luis L. Leon reservoir, located in Northern Mexico. The considered species were Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus. 238U and 234U activity concentration (AC) in fillet samples showed values of 0.007–0.014 and 0.01–0.02 Bq∙kg−1 wet weight (ww), respectively. Liver samples for L. cyanellus, C. carpio and I. furcatus present 210Po AC of 1.16–3.26, 0.70–1.13 and 0.93–1.37 Bq∙kg−1 ww. Arsenic, mercury and lead concentration intervals in fillet samples were 0.13–0.39, 0.005–0.126 and 0.009–0.08 mg∙kg−1 ww, respectively, while in gill samples they were 0.11–0.43, 0.002–0.039 and 0.02–0.26 mg∙kg−1 ww. The elemental Bioaccumulation Factor (BAF) for fish tissues with respect to their concentrations in water was determined. L. cyanellus showed the highest BAF values for As and total U, being BAFAs = 37 and 40 L∙kg−1 in fillet and gills, respectively, and BAFU total = 1.5 L∙kg−1 in fillet. I. furcatus showed the highest BAF values for Hg and Pb, being BAFHg = 40 and 13 L∙kg−1 in fillet and gills, and BAFPb = 6.5 and 22 L∙kg−1 in fillet and gills, respectively. Some metal(loid) concentrations are slightly higher than European regulations for fish fillets. The difference in concentrations of metal(loid)s in fillet among the studied species is probably due to their differences in diet and habitat. PMID:24968208

  9. Measurement and Analysis of Specific Activities of 238U, 232Th,226Ra, 40K and 137Cs in Soil Samples from Phatthalung Province (Thailand) using Gamma Ray Spectrometry

    International Nuclear Information System (INIS)

    Daoh, Murnee; Kessaratikoon, Prasong; Udomsomporn, Suchin

    2011-06-01

    Full text: Specific activity of natural (238 U , 232 T h, 226 R a and 40 K ) and anthropogenic radionuclide (137 C s) in 109 soil samples collected from 11 districts in Phathalung province have been measured and analyzed. Experimental results were obtained by using a high purity germanium (HPGe) detector and gamma spectrometry analysis system at Nuclear and Material Physics laboratory in Department of Physics Faculty of Science Thaksin University Songkhla Campus. Gamma ray radioactive standard sources 60 C o, 137 C s and 133 B a were used to calibrate the measurement system. The KCl and two reference materials (RGU-1 and RGTh-1) obtained from the International Atomic Energy Agency were also used to analyze and compute the 40 K , 238 U (or 226 R a) and 232 T h specific activity in all soil samples. The IAEA/SL-2 was also used to evaluate the specific activity of 137 C s in all soil samples. The measuring time of each sample was 10,800 seconds. It was found that specific activity ranged from 148.17 to 11276.78 Bq/kg for 40 K , 58.29 to 518.45 Bq/kg for 226 R a, 8.40 to 236.19 Bq/kg for 232 T h and 0.00 tp 12.39 Bq/kg for 137 C s with mean values of 3573.35 ± 203.89 Bq/kg, 135.89 ± 6.71 Bq/kg, 76.34 ± 5.32 Bq/kg and 1.05 ± 0.70 Bq/kg respectively. Furthermore, absorbed dose rate in air (D), radium equivalent activity (Ra e q), external hazard index (H e x), and annual effective dose rate (AEDout) of this area were also evaluated by using the mean values of specific activities of the 40 K , 226 R a and 232 T h. Moreover, the experimental results were also compared with Office of Atoms for Peace (OAP) research data, Thailand and global radioactivity measurement and evaluations. The radioactive contour maps of specific activities of natural and anthropogenic radionuclides from this study were created by using the program ArcGis Version 9.2

  10. Thermoluminescent characteristics of diopside-teflon composites for radiation dosimetry

    International Nuclear Information System (INIS)

    Melo, A.P.; Caldas, L.V.E.

    2006-01-01

    Diopside - Teflon composites were been studied in relation to their dosimetric properties for high-dose dosimetry. Diopside from Minas Gerais, Brazil, CaMg(Si 2 O 6 ), was obtained in form of rude mineral with inclusions of quartz. The samples were prepared and only Diopside grains obtained. Pellets of Diopside-Teflon composites were prepared in the proportion of 2(Teflon): 1 (Diopside).The TL response repeatability presented a maximum coefficient of variation of 7.5%. The calibration curve is linear between 0.5 Gy and 1 kGy. TL emission spectra present three emissions of similar intensities at 570 nm, 590 nm and between 610-635 nm. The results suggest that the material presents good characteristics for use as high-dose radiation detectors. (Author)

  11. The effect of cloud shape on radiative characteristics

    International Nuclear Information System (INIS)

    Welch, R.M.; Zdunkowski, W.G.

    1981-01-01

    Cumulus cloud radiative characteristics are calculated using Monte-Carlo codes as a function of solar zenith angle for clouds approximated by hemispherical, cylindrical and combination-type geometries. Values of cloud reflectivity, transmissivity and absorptivity are compared with values computed from assuming cubic and rectangular geometries, the basis for most previous finite cloud calculations. Poor agreement is obtained at large cloud sizes and only marginal agreement is obtained at small cloud sizes. Two approximations based upon various scalings of cloud optical depth (extinction parameters) are also constructed, but with limited success in reproducing the values produced by the convex shaped clouds. Reasonable agreement among the various approximations occurs at large solar zenith angles, but extremely poor agreement may occur at small angles. (orig./WB) [de

  12. Characteristics of outage radiation fields around various reactor components

    International Nuclear Information System (INIS)

    Verzilov, Y.; Husain, A.; Corbin, G.

    2008-01-01

    Full text: Activity monitoring surveys, consisting of gamma spectroscopy and dose rate measurements, of various CANDU station components such as the reactor face, feeder cabinet, steam generators and moderator heat exchangers are often performed during shutdown in order to trend the transport of activity around the primary heat transport and moderator systems. Recently, the increased dose expenditure for work such as feeder inspection and replacement in the reactor vault has also spurred interest in improved characterization of the reactor face fields to facilitate better ALARA decision making and hence a reduction in future dose expenditures. At present, planning for reactor face work is hampered by insufficient understanding of the relative contribution of the various components to the overall dose. In addition to the increased dose expenditure for work at the reactor face, maintenance work associated with horizontal flux detectors and liquid injection systems has also resulted in elevated dose expenditures. For instance at Darlington, radiation fields in the vicinity of horizontal flux detectors (HFD) and Liquid Injection Shutdown System (LISS) nozzle bellows are trending upwards with present contact fields being in the range 16-70 rem/h and working distance fields being in the range 100-500 mrem/h. This paper presents findings based on work currently being funded by the CANDU Owners Group. Measurements were performed at Ontario Power Generation's Pickering and Darlington nuclear stations. Specifically, the following are addressed: Characteristics of Reactor Vault Fields; Characteristics of Steam Generator Fields; Characteristics of Moderator Heat Exchanger Fields. Measurements in the reactor vault were performed at the reactor face, along the length of end fittings, along the length of feeders, at the bleed condenser and at the HFD and LISS nozzle bellows. Steam generator fields were characterized at various elevations above the tube sheet, with and without the

  13. Influence of soil parameters on the linearity of the soil-to-plant transfer process of {sup 238}U and {sup 226}Ra

    Energy Technology Data Exchange (ETDEWEB)

    Blanco Rodriguez, P.; Vera Tome, F. [Natural Radioactivity Group. Universidad de Extremadura, 06071 Badajoz (Spain); Lozano, J.C. [Laboratorio de Radiactividad Ambiental. Universidad de Salamanca, 37008 Salamanca (Spain)

    2014-07-01

    Transfer from soil to plant is an important input of radionuclides into the food chain. Also, the mobility of radionuclides in soils is enhanced through their passage into the plant compartment. Thus, the soil-to-plant transfer of radionuclides raises the potential human dose. In radiological risk assessment models, this process is usually considered to be an equilibrium process such that the activity concentration in plants is linearly related to the soil concentration through a constant transfer factor (TF). However, the large variability present by measured TF values leads to major uncertainties in the assessment of risks. One possible way to reduce this variability in TF values is to parametrize their determination. This paper presents correlations of TF with the major element concentrations in soils. The findings confirm the major influence of the chemical environment of a soil on the assimilation process. The variability of TF might be greatly reduced if only the labile fraction were considered. Experiments performed with plants (Helianthus annuus L.) growing in a hydroponic medium appear to confirm this suggestion, showing a linear correlation between the plant and the soil solution activity concentrations. Extracting the labile fraction of a real soil is no trivial task, however. A possible operationally definable method is to consider the water-soluble together with the exchangeable fractions of the soil. Studies performed in granitic soils showed that the labile concentration of uranium and radium strongly depended on the soil's textural characteristics. In this sense, a parametrization is proposed of the labile uranium and radium concentration as a function of the soil's granulometric parameters. (authors)

  14. Characteristics of sound radiation from turbulent premixed flames

    Science.gov (United States)

    Rajaram, Rajesh

    Turbulent combustion processes are inherently unsteady and, thus, a source of acoustic radiation, which occurs due to the unsteady expansion of reacting gases. While prior studies have extensively characterized the total sound power radiated by turbulent flames, their spectral characteristics are not well understood. The objective of this research work is to measure the flow and acoustic properties of an open turbulent premixed jet flame and explain the spectral trends of combustion noise. The flame dynamics were characterized using high speed chemiluminescence images of the flame. A model based on the solution of the wave equation with unsteady heat release as the source was developed and was used to relate the measured chemiluminescence fluctuations to its acoustic emission. Acoustic measurements were performed in an anechoic environment for several burner diameters, flow velocities, turbulence intensities, fuels, and equivalence ratios. The acoustic emissions are shown to be characterized by four parameters: peak frequency (Fpeak), low frequency slope (beta), high frequency slope (alpha) and Overall Sound Pressure Level (OASPL). The peak frequency (Fpeak) is characterized by a Strouhal number based on the mean velocity and a flame length. The transfer function between the acoustic spectrum and the spectrum of heat release fluctuations has an f2 dependence at low frequencies, while it converged to a constant value at high frequencies. Furthermore, the OASPL was found to be characterized by (Fpeak mfH)2, which resembles the source term in the wave equation.

  15. Impact of phonon coupling on the radiative nuclear reaction characteristics

    Directory of Open Access Journals (Sweden)

    Achakovskiy Oleg

    2016-01-01

    Full Text Available The pygmy dipole resonance and photon strength functions (PSF in stable and unstable Ni and Sn isotopes are calculated within the microscopic self-consistent version of the extended theory of finite Fermi systems in the quasiparticle time blocking approximation. The approach includes phonon coupling (PC effects in addition to the standard QRPA approach. The Skyrme force SLy4 is used. A pygmy dipole resonance in 72Ni is predicted at the mean energy of 12.4 MeV exhausting 25.7% of the total energy-weighted sum rule. With our microscopic E1 PSFs in the EMPIRE 3.1 code, the following radiative nuclear reaction characteristics have been calculated for several stable and unstable even-even Sn and Ni isotopes: 1 neutron capture cross sections, 2 corresponding neutron capture gamma-spectra, 3 average radiative widths of neutron resonances. Here, three variants of the microscopic nuclear level density models have been used and a comparison with the phenomenological generalized superfluid model has been performed. In all the considered properties, including the recent experimental data for PSF in Sn isotopes, the PC contributions turned out to be significant, as compared with the QRPA one, and necessary to explain the available experimental data.

  16. Ultra-Wideband Printed Slot Radiators with Controllable Frequency Characteristics

    Directory of Open Access Journals (Sweden)

    S. L. Chernyshev

    2015-01-01

    Full Text Available We have studied the possibility of creating ultra-wideband (UWB antennas with controlled frequency response of matching based on the printed slot antenna Vivaldi by introducing controlled resonators directly into the structure of the radiator. In the area of irregular slotline there are printed switched resonators with variable capacitance (varactor model, which allow tuning the frequency characteristics for each state of switching cavities, providing bandpass and band-barrage properties of the antenna. The investigation of reconfigurable printed resonators in the system of reconfigurable resonators of a bandpass filter is conducted. The paper considers filter to provide restructuring in the band (3-9 GHz. Electrodynamic simulation of the device was carried out in the time domain using a finite integration method. A bandstop reconfigurable filter is also investigated. The filter located on the substrate opposite the slit is based on tunable L-shaped resonator that has one end connected to the short-circuitor through the board metallization; the other end remains open and is brought into the region of interaction with the slotline. Such filter provides an effective narrow-band suppression and can be easily tuned to the desired frequency channel. The combination of these two types of filters allows you to create a controlled print Vivaldi slot antenna with combined properties. The paper investigates parameters of the scattering and radiation pattern of the antenna in different modes.

  17. Fusion barrier distributions from capture and quasi-elastic excitation functions measured in reaction 36S, 48Ca, 64Ni+238U

    International Nuclear Information System (INIS)

    Kozulin, E. M.

    2009-01-01

    The subbarrier fusion enhancement in reactions with heavy ions were explained by taking into account coupling between relative motion and intrinsic degrees of freedom of interacting nuclei. The coupling of reaction channels manifests itself in the potential barrier between interacting nuclei giving rise to a distribution of fusion barrier instead of single barrier.Capture and quasi-elastic scattering excitation functions at backward angles were measured for 3 6S , 4 8C a, 6 4N i+2 38U reactions systems at energies close and below the Coulomb barrier (i.e. when the influence of the shell effects on the fusion and characteristics of the decay of the composite system is considerable). Representations of the barrier distributions were extracted from both capture and quasi-elastic data. The experimental representations of barrier distributions were compared with coupled-channel calculations using CCFULL code. The major part of these experiments has been performed at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR, Dubna); at the TANDEM-ALPI accelerator of the LNL (INFN, Legnaro, Italy) and at the Accelerator Laboratory of University of Jyvaeskylae (JYFL, Finland) using a time-of-flight spectrometer of fission fragments CORSET (CORrelation SET-up.) The extraction of the masses and Total Kinetic Energy (TKE) of the binary reaction products is based upon the analysis of the two-body velocity In the case of the fusion-fission and quasi-fission processes, the observed peculiarities of mass and energy distributions of the fragments, the ratio between the fusion-fission and quasi-fission cross sections are determined deformations of interaction nuclei and angular momentum carried in the di-nuclear system and the shell structure of the formed fragments. In this work, the high-precision capture and quasi-elastic scattering excitation function data are presented.The influence of projectile and target excitations and nucleon transfer on fusion barrier

  18. Radiation and thermal characteristics of mouse lymphoma cells and their radiation-sensitive mutant

    International Nuclear Information System (INIS)

    Baba, Yuji; Yasunaga, Tadamasa; Uozumi, Hideaki; Takahashi, Mutsumasa; Sawada, Shozo.

    1988-01-01

    Radiation and thermal characteristics of L5178Y cells and their radiation-sensitive mutant M10 cells were studied by the colony-forming method and the dye-exclusion method using eosin-Y. Although M10 cells were remarkably radiation-sensitive compared with L5178Y cells, it was diffcult to cause interphase death of M10 after a large dose of irradiation. After heat treatments, L5178Y cells revealed more cell destruction and were stained well by eosin-Y, but it was relatively difficult to produce cell destruction of M10 cells, which showed poor staining by eosin-Y. When assayed by the colony-forming method, M10 cells were also heat-resistant compared to L5178Y. The dye-exclusion rate was closely correlated with cell survival after hyperthermia of L5178Y cells, suggesting that this is a simple method of detecting the thermosensitivity and thermotolerance of cancer cells. The difference in survival of L5178Y cells and M10 cells after combined treatment with gamma irradiation and hyperthermia was smaller than with gamma irradiation alone. It was also found that there was a relationship between radiation-induced interphase death and hyperthermia-induced interphase death, and that interphase death accounted for a major part of cell death caused by hyperthermia in mouse leukemia cells. (author)

  19. Estimation of covariances of {sup 16}O, {sup 23}Na, Fe, {sup 235}U, {sup 238}U and {sup 239}Pu neutron nuclear data in JENDL-3.2

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Keiichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakajima, Yutaka; Kawano, Toshihiko; Oh, Soo-Youl; Matsunobu, Hiroyuki; Murata, Toru

    1997-10-01

    Covariances of nuclear data have been estimated for 6 nuclides contained in JENDL-3.2. The nuclides considered are {sup 16}O, {sup 23}Na, Fe, {sup 235}U, {sup 238}U, and {sup 239}Pu, which are regarded as important for the nuclear design study of fast reactors. The physical quantities for which covariances are deduced are cross sections, resolved and unresolved resonance parameters, and the first order Legendre-polynomial coefficient for the angular distribution of elastically scattered neutrons. As for {sup 235}U, covariances were obtained also for the average number of neutrons emitted in fission. The covariances were estimated by using the same methodology that had been used in the JENDL-3.2 evaluation in order to keep a consistency between mean values and their covariances. The least-squares fitting code GMA was used in estimating covariances for reactions of which JENDL-3.2 cross sections had been evaluated by taking account of measurements. In nuclear model calculations, the covariances were calculated by the KALMAN system. The covariance data obtained were compiled in the ENDF-6 format, and will be put into the JENDL-3.2 Covariance File which is one of JENDL special purpose files. (author). 193 refs.

  20. Analysis of photofission reactions of 235U, 238U, 232Th, 209Bi, natPb, 197Au, natPt, natW, 181Ta, and 27Al by photons of 69 MeV

    International Nuclear Information System (INIS)

    Paiva, Eduardo de

    1997-04-01

    Fission reactions induced in 235 U, 238 U, 232 Th, 209 Bi nat Pb, 197 Au, nat Pt, nat W, 181 Ta. and 27 Al nuclei by monochromatic photons of 69 MeV produced at the LADON facility of the Frascati National Laboratories (INFN-LNF, Frascati, Italy) have been analyzed on the basis of a simplified two-step model. In the first step of the reaction the incoming photon is considered to be absorbed by a neutron-proton pair ('quasi-deuteron') leading to excitation of the nucleus, followed, in the second step, by a mechanism of particle evaporation-fission competition for the excited residual nucleus. Estimates of nuclear fissility at 69 MeV show to be critically dependent on the parameter r (ratio of the level-density parameter at the fission saddle point to the level-density parameter of the residual nucleus after neutron evaporation), which can be determined in a semiempirical way from induced fission reaction data for various nuclei obtained at 60 - 80 MeV of excitation energy. Fissilities calculated by means of the simplified photofission reactions model are then compared with experimental data available in the literature. (author)

  1. Measurements of fission product yield in the neutron-induced fission of {sup 238}U with average energies of 9.35 MeV and 12.52 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Mukerji, Sadhana; Krishnani, Pritam Das; Suryanarayana, Saraswatula Venkat; Naik, Haladhara; Goswami, Ashok [Bhabha Atomic Research Centre, Mumbai (India); Shivashankar, Byrapura Siddaramaiah [Manipal University, Manipal (India); Mulik, Vikas Kaluram [University of Pune, Pune (India)

    2014-07-15

    The yields of various fission products in the neutron-induced fission of {sup 238}U with the flux-weighted averaged neutron energies of 9.35 MeV and 12.52 MeV were determined by using an off-line gamma ray spectroscopic technique. The neutrons were generated using the {sup 7}Li(p, n) reaction at Bhabha Atomic Research Centre-Tata Institute of Fundamental Research Pelletron facility, Mumbai. The gamma- ray activities of the fission products were counted in a highly-shielded HPGe detector over a period of several weeks to identify the decaying fission products. At both the neutron energies, the fission-yield values are reported for twelve fission product. The results obtained from the present work have been compared with the similar data for mono-energetic neutrons of comparable energy from the literature and are found to be in good agreement. The peak-to-valley (P/V) ratios were calculated from the fission-yield data and were found to decreases for neutron energy from 9.35 to 12.52 MeV, which indicates the role of excitation energy. The effect of the nuclear structure on the fission product-yield is discussed.

  2. Measurements of fission product yield in the neutron-induced fission of 238U with average energies of 9.35 MeV and 12.52 MeV

    Science.gov (United States)

    Mukerji, Sadhana; Krishnani, Pritam Das; Shivashankar, Byrapura Siddaramaiah; Mulik, Vikas Kaluram; Suryanarayana, Saraswatula Venkat; Naik, Haladhara; Goswami, Ashok

    2014-07-01

    The yields of various fission products in the neutron-induced fission of 238U with the flux-weightedaveraged neutron energies of 9.35 MeV and 12.52 MeV were determined by using an off-line gammaray spectroscopic technique. The neutrons were generated using the 7Li(p, n) reaction at Bhabha Atomic Research Centre-Tata Institute of Fundamental Research Pelletron facility, Mumbai. The gamma- ray activities of the fission products were counted in a highly-shielded HPGe detector over a period of several weeks to identify the decaying fission products. At both the neutron energies, the fission-yield values are reported for twelve fission product. The results obtained from the present work have been compared with the similar data for mono-energetic neutrons of comparable energy from the literature and are found to be in good agreement. The peak-to-valley (P/V) ratios were calculated from the fission-yield data and were found to decreases for neutron energy from 9.35 to 12.52 MeV, which indicates the role of excitation energy. The effect of the nuclear structure on the fission product-yield is discussed.

  3. Study of the desintegration of short-life fission products. Application to the mass distribution in the fission of 238U and 233U induced by 14MeV neutrons

    International Nuclear Information System (INIS)

    Cavallini, Pierre.

    1975-01-01

    Nuclear spectrometry of short-life fission products was investigated, together with direct applications to the study of mass and charge distribution in fission reactions. It is shown that, by choosing judiciously the target in which the fission product is created and owing to the differences in stabilities and evaporation temperatures of the compounds obtained, it is possible to separate some elements. For example, niobium was separated by heating after irradiation of a mixture of UC and RuCl 3 , and sublimation in a tube with temperature gradient. It was thus possible to study the 99 Nb isotope. Other classical chemical separation processes were used for yttrium and strontium. The half-lifes beta and gamma spectra, decay schemes of 93 Sr, 94 Y and 95 Y were studied. It was shown how to obtain mass distribution in fission using a nondestructive gamma analysis method. As an application, results obtained in the fission of 233 U and 238 U at 14 MeV are given [fr

  4. Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    Science.gov (United States)

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

    2017-09-01

    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 combi- nation of fission counting using specially designed dual-fission chambers and -ray counting. Each dual-fission chamber is a back-to-back ioniza- tion chamber encasing an activation target in the center with thin de- posits of the same target isotope in each chamber. This method allows for the direct measurement of the total number of fissions in the activa- tion 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 2 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 and 14.8 MeV. New data in the second chance fission region of 5.5 - 9 MeV are included. Work performed for the U.S. Department of Energy by Los Alamos National Security, LLC under Contract DE-AC52-06NA25396.

  5. Characteristics of the radiation prevention metrology laboratory 'Cajavec' - Banjaluka

    International Nuclear Information System (INIS)

    Tomljenovic, I.; Ninkovic, M.; Kolonic, Dz.

    2004-01-01

    Radiation metrology laboratory built in the factory 'Cajavec' in Banja Luka, planed for gauge the detectors of ionization radiation. Laboratory as part of the large factory building , thus projected and formed according to positive radiation principles. Walls are constructed of basic concrete, main entrance of lead, approaching the radiation bench from the back side. Sound and light signal system connected with dosemeter for showing mini dose of radiation creating conditions for safe work of the dosemeterists. (author) [sr

  6. Neutron resonance parameters for 238U

    International Nuclear Information System (INIS)

    Poortmans, F.; Mewissen, L.; Cornelis, E.; Vanpraet, G.; Rohr, G.; Shelley, R.; Veen, T. van der; Weigmann, H.

    1977-01-01

    A series of total, capture and scattering cross section measurements using the neutron time-of-flight facility at the CBNM linear electron accelerator were performed. The neutron widths have been obtained for more than 400 resonances below 4.3 keV and the total capture width for 73 resonances

  7. Estimation of internal radiation dose to the adult Asian population from the dietary intakes of two long-lived radionuclides

    International Nuclear Information System (INIS)

    Iyengar, G.V.; Kawamura, H.; Dang, H.S.; Parr, R.M.; Wang, J.W.; Akhter, Perveen; Cho, S.Y.; Natera, E.; Miah, F.K.; Nguyen, M.S.

    2004-01-01

    Daily dietary intakes of two naturally occurring long-lived radionuclides, 232 Th and 238 U, were estimated for the adult population living in a number of Asian countries, using highly sensitive analytical methods such as instrumental and radiochemical neutron activation analysis (INAA and RNAA), and inductively coupled plasma mass spectrometry (ICP-MS). The Asian countries that participated in the study were Bangladesh (BGD), China (CPR), India (IND), Japan (JPN), Pakistan (PAK), Philippines (PHI), Republic of Korea (ROK) and Vietnam (VIE). Altogether, these countries represent more than 50% of the world population. The median daily intakes of 232 Th ranged between 0.6 and 14.4 mBq, the lowest being for Philippines and the highest for Bangladesh, and daily intakes of 238 U ranged between 6.7 and 62.5 mBq, lowest and the highest being for India and China, respectively. The Asian median intakes were obtained as 4.2 mBq for 232 Th and 12.7 mBq for 238 U. Although the Asian intakes were lower than intakes of 12.3 mBq (3.0 μg) 232 Th and 23.6 mBq (1.9 μg) 238 U proposed by the International Commission on Radiological Protection (ICRP) for the ICRP Reference Man, they were comparable to the global intake values of 4.6 mBq 232 Th and 15.6 mBq 238 U proposed by the United Nation Scientific Commission on Effects of Radiation (UNSCEAR). The annual committed effective doses to Asian population from the dietary intake of 232 Th and 238 U were calculated to be 0.34 and 0.20 μSv, respectively, which are three orders of magnitude lower than the global average annual radiation dose of 2400 μSv to man from the natural radiation sources as proposed by UNSCEAR

  8. Fractal characteristics correlation between the solar total radiation and net radiation on the apple tree canopy

    International Nuclear Information System (INIS)

    Meng Ping; Zhang Jingsong

    2005-01-01

    The characteristics correlation between solar total radiations(Q) and net radiation(R n) on the apple tree canopy at mainly growth stage in the hilly of Taihang Mountain are analyzed with fractal theory based on regression analysis. The results showed that:1)Q and R n had good liner correlation. The regression function was as the following:R n=0.740 8Q-32.436, which coefficient r is 0.981 1(n=26 279), F cal= 343 665.2 F 0.01 36 277=6.63; 2)The fractal dimension curves of Q and R n both had two no s caling regions, which circumscription time value of the inflexion was 453 and 441 minutes respectively.In the first region, fractal dimensions of Q and R n was 1.112 6, 1.131 9 respectively,and 1.913 6@@@ 1.883 4 in the second region.Those information showed that fractal characteristics of Q and R n is similar. So R n can be calculated with Q on the apple tree canopy

  9. Modern new nuclear fuel characteristics and radiation protection aspects.

    Science.gov (United States)

    Terry, Ian R

    2005-01-01

    The glut of fissile material from reprocessing plants and from the conclusion of the cold war has provided the opportunity to design new fuel types to beneficially dispose of such stocks by generating useful power. Thus, in addition to the normal reactor core complement of enriched uranium fuel assemblies, two other types are available on the world market. These are the ERU (enriched recycled uranium) and the MOX (mixed oxide) fuel assemblies. Framatome ANP produces ERU fuel assemblies by taking feed material from reprocessing facilities and blending this with highly enriched uranium from other sources. MOX fuel assemblies contain plutonium isotopes, thus exploiting the higher neutron yield of the plutonium fission process. This paper describes and evaluates the gamma, spontaneous and alpha reaction neutron source terms of these non-irradiated fuel assembly types by defining their nuclear characteristics. The dose rates which arise from these terms are provided along with an overview of radiation protection aspects for consideration in transporting and delivering such fuel assemblies to power generating utilities.

  10. Fluctuation characteristics of solar radiation in crop cultivation

    International Nuclear Information System (INIS)

    Hayashi, S.; Suzuki, H.

    1996-01-01

    The objective of this study was to clarify the fluctuation of solar radiation for long and short periods, which is very crucial for plant growth. Data obtained from a meteorological observatory were used to investigate solar radiation and sunshine duration for a long period. For a short period, observation of global solar radiation and sky solar radiation were conducted in a glass house and at an open field. (1) Yearly average percentage of solar radiation at Kagawa from 1973 to 1994 was 44.3%, and its coefficient of variation was 3.9%. The percentage of possible sunshine and the coefficient were larger than those of solar radiation, 47.3% and 56% respectively. (2) Percentage of possible solar radiation and percentage of possible sunshine showed seasonal variation. Those coefficients of variation both increased exponentially with cloud amount. (3) Variations of global solar radiation and direct solar radiation were more remarkable in the glass house than those in the open field, while variations of sky solar radiation were small in the house and at the open field. (4) The fluctuation of solar radiation observed every 5 minutes was presented as the difference of radiation, present value minus the preceding value. The difference was positive in the morning, negative in the afternoon at the open field. In the house both positive and negative values were obtained the whole day. (5) Diurnal variation of ratio of direct solar radiation to sky solar radiation showed a parabolic effect, whereas it had irregular and large fluctuations at the open field

  11. Determination of gamma radiation shielding characteristics of some tropical woods

    International Nuclear Information System (INIS)

    Aigbosuria, E. F.

    2011-01-01

    This study compares the shielding characteristics of twenty-two tropical woods by using gamma scintillation detection method. Woods sourced are Anogeisus Leiocarpus(Ayin), Nesogordonia Papverifera(Oro), Entandrophragma Microphyllum(Anunje), Brachystagia Eurycoma(Ako), Cassia Alata(Asunrun), Afzelia Africana(Apa-Igbo), Khaya Grandifoliala(Gedu), Piptadenistrum Africana(Agbonyin), Nanclea Diderrehii(Opepe), Khaya Ivorensis(Oganwo), Chlorophora Excelsa(Iroko), Masonia altissima(Odogi), Entandrophragma Angolense(Ijebo), Altium Sativum(Ayo), Albizia Zygia(Ayunre), Terminalia Superba(Afara), Cordia Millenii(Omo), Melania(Melania), Pycnanthus Angolensis(Akomu), Triplochitons Scleroxylon(Arere), Pine(Pine), Ceiba Pentradra(Araba). The intensities of the emergent radiation were measured, when each of these woods were placed between a scintillation detector and a standard radioactive source. Analysis of result obtained shows an appreciable evidence of radiation attenuation due to the changes in the chemical composition of the woods and the dependence of the attenuation coefficient on energy and densities of these woods. The descending order of attenuation coefficient determined are; Ayin, Oro, Anuje, Ako, Asunrun, Apa-igbo Gedu, Agbonyin, Opepe Oganwo, Iroko Odogi , Ayo, Ayunre, Afara, Omo, Melania, Akomu, Arere, Pine, Araba. For a constant energy of 0.101MeV, the attenuation coefficient are 0.190cm -1 , 0.165cm -1 , 0.163cm -1 , 0.156cm -1 , 0.149cm -1 , 0.143cm -1 , 0.133cm -1 , 0.132cm -1 , 0.127cm -1 , 0.124cm -1 , 0.085cm -1 , 0.123cm -1 , 0.122cm -1 , 0.113cm -1 , 0.101cm -1 , 0.088cm -1 , 0.087cm -1 , 0.086cm -1 , 0.082cm -1 respectively. The wood in descending order of dependence of attenuation coefficient on density are: Ayin,Oro, Anunje,Ako,Asunrun,Apa-Igbo, Gedu, Agbonyin, Opepe, Oganwo, Iroko, Odogi, Ijebo, Ayo, Ayunre, Afara, Omo, Melania, Akomu, Arere, Pine and Araba. The half value layer shows the thickness at various energy regions.

  12. Determination of gamma radiation shielding characteristics of some tropical woods

    Energy Technology Data Exchange (ETDEWEB)

    Aigbosuria, E F [Department of Computer Electronics/Physics, Lead City University, Ibadan (Nigeria)

    2011-10-24

    This study compares the shielding characteristics of twenty-two tropical woods by using gamma scintillation detection method. Woods sourced are Anogeisus Leiocarpus(Ayin), Nesogordonia Papverifera(Oro), Entandrophragma Microphyllum(Anunje), Brachystagia Eurycoma(Ako), Cassia Alata(Asunrun), Afzelia Africana(Apa-Igbo), Khaya Grandifoliala(Gedu), Piptadenistrum Africana(Agbonyin), Nanclea Diderrehii(Opepe), Khaya Ivorensis(Oganwo), Chlorophora Excelsa(Iroko), Masonia altissima(Odogi), Entandrophragma Angolense(Ijebo), Altium Sativum(Ayo), Albizia Zygia(Ayunre), Terminalia Superba(Afara), Cordia Millenii(Omo), Melania(Melania), Pycnanthus Angolensis(Akomu), Triplochitons Scleroxylon(Arere), Pine(Pine), Ceiba Pentradra(Araba). The intensities of the emergent radiation were measured, when each of these woods were placed between a scintillation detector and a standard radioactive source. Analysis of result obtained shows an appreciable evidence of radiation attenuation due to the changes in the chemical composition of the woods and the dependence of the attenuation coefficient on energy and densities of these woods. The descending order of attenuation coefficient determined are; Ayin, Oro, Anuje, Ako, Asunrun, Apa-igbo Gedu, Agbonyin, Opepe Oganwo, Iroko Odogi , Ayo, Ayunre, Afara, Omo, Melania, Akomu, Arere, Pine, Araba. For a constant energy of 0.101MeV, the attenuation coefficient are 0.190cm{sup -1}, 0.165cm{sup -1}, 0.163cm{sup -1}, 0.156cm{sup -1}, 0.149cm{sup -1}, 0.143cm{sup -1}, 0.133cm{sup -1}, 0.132cm{sup -1}, 0.127cm{sup -1}, 0.124cm{sup -1}, 0.085cm{sup -1}, 0.123cm{sup -1}, 0.122cm{sup -1}, 0.113cm{sup -1}, 0.101cm{sup -1}, 0.088cm{sup -1}, 0.087cm{sup -1}, 0.086cm{sup -1}, 0.082cm{sup -1} respectively. The wood in descending order of dependence of attenuation coefficient on density are: Ayin,Oro, Anunje,Ako,Asunrun,Apa-Igbo, Gedu, Agbonyin, Opepe, Oganwo, Iroko, Odogi, Ijebo, Ayo, Ayunre, Afara, Omo, Melania, Akomu, Arere, Pine and Araba. The half value

  13. Simulation of Thermal, Neutronic and Radiation Characteristics in Spent Nuclear Fuel and Radwaste Facilities

    International Nuclear Information System (INIS)

    Poskas, P.; Bartkus, G.

    1999-01-01

    The overview of the activities in the Division of Thermo hydro-mechanics related with the assessment of thermal, neutronic and radiation characteristics in spent nuclear fuel and radwaste facilities are performed. Also some new data about radiation characteristics of the RBMK-1500 spent nuclear fuel are presented. (author)

  14. Drying characteristics of rough rice by far-infrared radiation heating

    International Nuclear Information System (INIS)

    Matsuoka, T.

    1990-01-01

    The relationship between the heat radiation characteristics of a far-infrared radiation heater and the drying characteristics of rough rice was investigated to determine the basic data required for utilization of far-infrared rays for drying rough rice. Results of investigations are discussed in detail

  15. Radiators in hydronic heating installations structure, selection and thermal characteristics

    CERN Document Server

    Muniak, Damian Piotr

    2017-01-01

    This book addresses key design and computational issues related to radiators in hydronic heating installations. A historical outline is included to highlight the evolution of radiators and heating technologies. Further, the book includes a chapter on thermal comfort, which is the decisive factor in selecting the ideal heating system and radiator type. The majority of the book is devoted to an extensive discussion of the types and kinds of radiators currently in use, and to identifying the reasons for the remarkable diversity of design solutions. The differences between the solutions are also addressed, both in terms of the effects of operation and of the thermal comfort that needs to be ensured. The book then compares the advantages and disadvantages of each solution, as well as its potential applications. A detailed discussion, supported by an extensive theoretical and mathematical analysis, is presented of the computational relations that are used in selecting the radiator type. The dynamics of radiator hea...

  16. Natural and anthropogeneous radiation in the Erzgebirge: Risk factor radon

    International Nuclear Information System (INIS)

    Jacobi, W.

    1992-01-01

    The geological formations in the saxoinian-thuringian low mountain range contain rocks with a relatively high share of uranium ( 238 U) and its follow-up product radium ( 226 Ra). Independent of mining this results in increased radiation levels to which the local population has always been exposed. Natural radiation levels may, of course, vary strongly from one location to the next and therefore human exposure varies accordingly. (orig.) [de

  17. Analysis of radiation level on dinosaur fossil in Zigong

    International Nuclear Information System (INIS)

    Yang Changshu; Liang Shuzhi; Fan Zhengnian.

    1995-01-01

    Study on radiation level of dinosaur fossil and environment in conservation zone in Zigong, Sichuan has been done. The results showed that the γ radiation dose and radioactivity strength of 232 Th and 40 K in dinosaur fossil, soil and rock in the conservation zone were within the limits of radioactive background value in Zigong. Radioactivity strength of 238 U, 226 Ra in dinosaur fossil were 26.6 and 29.2 times higher than the rock of same layer respectively

  18. Effect of radiation on microbiologic characteristics of M. tuberculosis

    International Nuclear Information System (INIS)

    Zack, M.B.; Stottmeier, K.; Berg, G.; Kazemi, H.

    1974-01-01

    The effect of irradiation on mutation (expressing itself as drug resistance) and on viability of Mycobacterium tuberculosis was studied in vitro. Forty-two identical cultures of H37-Rv (M. tuberculosis) were exposed to different levels of cobalt radiation (10, 100, 1,000, 2,500, 5,000, 10,000, and 20,000 rads) with six samples used for each of the seven radiation levels. Equivalent samples exposed to zero rads and samples handled and stored identically formed the controls. Coded cultures were read in a double-blind fashion to determine the number of surviving organisms and sensitivities to nine different antituberculosis drugs. Organism viability began to decrease at radiation levels of 1,000 rads and decreased linearly with higher levels of radiation. Three of the 42 radiated cultures developed drug-resistant organisms (one to INH, one to PAS, a third to SM). This drug resistance occurred at levels of clinical significance (greater than 1 percent control) as well as in amounts exceeding probability values for chance resistance mutation. High radiation levels such as occur in radiotherapeutic doses decrease the viability of M. tuberculosis. Radiation may also induce genetic mutation expressed as primary drug resistance. (U.S.)

  19. Radiation Exposure to Concrete in Israel

    International Nuclear Information System (INIS)

    Haquin, G.; Kovler, K.; Yungrais, G. Z.; Lavi, N.

    2014-01-01

    Most building materials of terrestrial origin contain small amounts of radionuclides of natural origin, mainly from the Uranium (238U) and Thorium (232Th) decay chains and the radioactive isotope of potassium, 40K. The external radiation exposure is caused by gamma emitting radionuclides, which in the uranium series mainly belong to the decay chain segment starting with Radium (226Ra). The internal (by inhalation) radiation exposure is due to Radon (222Rn), and its short lived decay products, exhaled from building materials into the room air. Due to economical and environmental reasons there is an increased tendency to use industrial by-products containing relatively high concentrations of radionuclides of natural origin in the building material industry. Fly ash (FA), produced as by-product in the combustion of coal, is extensively used in Israel since mid eighties of the last century in concrete and as an additive to cement . The increase of 226Ra activity concentration, the mineralogical characteristics of the FA and of the concrete may influence on the radon exhalation rate and consequently on the radon exposure of the public. The recently published Israeli Standard 5098 (IS 5098) 'Content of natural radioactive elements in building products' limits the content of natural radionuclides as well as the radon emanation from concrete. This paper presents a compilation of three studies conducted at Soreq Nuclear Research Centre (SNRC), Technion, NRG and Environmental Lab BGU (ELBGU) to investigate and quantify the influence of FA addition in concrete

  20. Origin and geochemical behavior of uranium in marine sediments. Utilization of the {sup 234}U/{sup 238}U ratio in marine geochemistry; Origine et comportement geochimique de l`uranium dans les sediments marins. Utilisation du rapport ({sup 234}U/{sup 238}U) en geochimie marine

    Energy Technology Data Exchange (ETDEWEB)

    Organo, Catherine [Paris-11 Univ., 91 - Orsay (France)

    1997-01-20

    The first part of this thesis presents the current situation of knowledge of uranium in marine environment. The second part describes the methods of analysis as well as the material support of the study, i.e., the sediments and marine deposits investigated. The third part is dedicated to the study of uranium mobility in marine sediments characterized by detrital terrigenous composition (pelagic clays). This approach allowed quantifying the entering and leaving flux of uranium after the sediment settling and, to discuss, on this basis, the consequences on the uranium oceanic balance. In the third part the origin and behavior of uranium in zones of high surface productivity is studied. The uranium enrichments observed in the hemi-pelagic sediments of the EUMELI (J.G.O.F.S.-France) programme will constitute a material of study adequate for measuring the variations in the {sup 234}U/2{sup 38U} ratio in solid phase, in response to the oxido-reducing characteristics of the sediment. Thus establishing the origin of the trapped uranium has been possible. Also, the nature of the sedimentary phases related to uranium in bio-genetic sediments in the Austral Ocean was determined. Thus a relationship between the variations in the {sup 234}U/{sup 238} and the diagenetic transformations was possible to establish. Finally in the fifth part a study of the behavior of uranium in a polymetallic shell characteristic for deposits of hydrogenized origin 146 refs., 57 figs., 23 tabs.

  1. Clinico-morphological characteristics of reparation of acute radiation ulcer

    International Nuclear Information System (INIS)

    Petrik, V.D.; Yakovleva, N.D.; Bardychev, M.S.

    1979-01-01

    The mechanism of reparative processes under the effect of various drugs was studied in experimental acute radiation ulcer of rats. It was established that at the stage of marked exudative-necrotic processes the use of antiinflammatory and antiexudative substances (bariz, dimethylsulfoxyde) led to normalization of the microcirculation that reduced the time of radiation ulcer healing. The use of anabolic steroids (retabolil) intensified metabolism that also produced a favourable effect on the reparative processes

  2. Radiation Effects on Thermoluminescence Characteristics of HDPE Containing Additives

    International Nuclear Information System (INIS)

    Kim, Ki Yup; Lee, Chung; Ryu, Boo Hyung

    2005-01-01

    Polymeric materials are widely used for electrical insulation in a broad range of applications that cover the power supply industry to inner and outer space. However, the electrical performance of these materials could be compromised by their working environment and one of the most deleterious is that where a nuclear radiation is present. Radiation effects on polymers can be interpreted by two main reactions, a cross-linking reaction and degradation reactions or a main-chain scission process. There are no absolute rules for determining whether or not any given polymer will cross-link or degrade upon an irradiation. But, the polymers can be divided empirically into two groups; polymers which are crosslinked by radiation (especially by the incorporation of chemical cross-linking promoters) and polymers which degrade by radiation into a product of lower molecular weight due to random main-chain scission process. These polymers become very hard and brittle with a high dose of radiation. Most polymeric materials contain some stabilizers such as flame retardant and antioxidant to prevent combustion and oxidation. Because of these additives, degradation mechanism of the polymer became complicated. Many of the novel properties of the insulating materials used in nuclear power plants are important for radiation degradation. Therefore we have used the thermal methods such as thermoluminescence (TL) detection for irradiated high density polyethylene containing flame retardant and antioxidant

  3. Energy Dependence of Fission Product Yields from 235U, 238U and 239Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    Science.gov (United States)

    Gooden, M. E.; Arnold, C. W.; Becker, J. A.; Bhatia, C.; Bhike, M.; Bond, E. M.; Bredeweg, T. A.; Fallin, B.; Fowler, M. M.; Howell, C. R.; Kelley, J. H.; Krishichayan; Macri, R.; Rusev, G.; Ryan, C.; Sheets, S. A.; Stoyer, M. A.; Tonchev, A. P.; Tornow, W.; Vieira, D. J.; Wilhelmy, J. B.

    2016-01-01

    Fission Product Yields (FPY) have historically been one of the most observable features of the fission process. They are known to have strong variations that are dependent on the fissioning species, the excitation energy, and the angular momentum of the compound system. However, consistent and systematic studies of the variation of these FPY with energy have proved challenging. This is caused primarily by the nature of the experiments that have traditionally relied on radiochemical procedures to isolate specific fission products. Although radiochemical procedures exist that can isolate all products, each element presents specific challenges and introduces varying degrees of systematic errors that can make inter-comparison of FPY uncertain. Although of high importance in fields such as nuclear forensics and Stockpile Stewardship, accurate information about the energy dependence of neutron induced FPY are sparse, due primarily to the lack of suitable monoenergetic neutron sources. There is a clear need for improved data, and to address this issue, a collaboration was formed between Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL) and the Triangle Universities Nuclear Laboratory (TUNL) to measure the energy dependence of FPY for 235U, 238U and 239Pu. The measurements have been performed at TUNL, using a 10 MV Tandem Van de Graaff accelerator to produce monoenergetic neutrons at energies between 0.6 MeV to 14.8 MeV through a variety of reactions. The measurements have utilized a dual-fission chamber, with thin (10-100 μg/cm2) reference foils of similar material to a thick (100-400 mg) activation target held in the center between the chambers. This method allows for the accurate determination of the number of fissions that occurred in the thick target without requiring knowledge of the fission cross section or neutron fluence on target. Following activation, the thick target was removed from the dual-fission chamber and gamma

  4. Quantification of "2"3"2Th, "2"3"4U, "2"3"5U and "2"3"8U in river mollusks by magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS)

    International Nuclear Information System (INIS)

    Arevalo R, D. L.; Hernandez M, H.; Romero G, E. T.; Lara A, N.; Alfaro de la T, M. C.

    2016-09-01

    The present work deals with the methodology established for the quantification of "2"3"2Th, "2"3"4U, "2"3"8U and "2"3"5U in the shell of gastropod mollusks collected in the rivers Valles, Coy and Axtla of San Luis Potosi, Mexico, which belong to the Panuco River basin; these rivers have as main source of pollution the discharge of municipal sewage, waste from small industries, agricultural and cattle residues and from natural sources. Conventional methods for measuring radio-nuclides are confronted with certain conditions related to the requirement in measurement, basically in the characterization that is related to the concepts of precision and accuracy. The analysis of the gastropod mollusk shell was performed by the Icp-SFMS technique; the main advantages of this technique lie in the isotope quantification capacity, the high precision and the low limits of detection, in this study are very important because these elements are in concentrations between ppb and ppt. This technique allowed the analysis of the samples having a complex matrix by the presence CaCO_3 minimizing the interferences thanks to the ionization efficiency of the Ar plasma. For the species Pachychilus monachus were found concentrations of "2"3"2Th of 0.16-5.37 μg/g and of total U of 0.101-4.081 μg/g being this species where the highest values of total U were found. For Thiara (melanoids) tuberculata the lowest values were found among the different species ("2"3"2Th 0.61-3.61 μg/g and total U 0.006-0.042 μg/g), for Pachychilus suturalis, values of "2"3"2Th of 0.58-6.4 μg/g and for Pachychilus sp. were found between 0.26-7.62 μg/g and for total U values between 0.28-3.33 μg/g. The method offers several advantages: speed, good precision, low values of quantification limits and high sensitivity in the measurement of radio-nuclides and heavy metals. (Author)

  5. Energy Dependence of Fission Product Yields from {sup 235}U, {sup 238}U and {sup 239}Pu for Incident Neutron Energies Between 0.5 and 14.8 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Gooden, M.E., E-mail: m_gooden@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Arnold, C.W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Becker, J.A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Bhatia, C. [McMaster University, Ontario (Canada); Bhike, M. [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Bond, E.M.; Bredeweg, T.A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Fallin, B. [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Fowler, M.M. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Howell, C.R. [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Kelley, J.H. [Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Department of Physics, North Carolina State University, Raleigh, North Carolina 27605 (United States); Krishichayan [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Macri, R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Rusev, G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ryan, C.; Sheets, S.A.; Stoyer, M.A.; Tonchev, A.P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Tornow, W. [Department of Physics, Duke University,Durham, North Carolina 27708 (United States); Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); and others

    2016-01-15

    Fission Product Yields (FPY) have historically been one of the most observable features of the fission process. They are known to have strong variations that are dependent on the fissioning species, the excitation energy, and the angular momentum of the compound system. However, consistent and systematic studies of the variation of these FPY with energy have proved challenging. This is caused primarily by the nature of the experiments that have traditionally relied on radiochemical procedures to isolate specific fission products. Although radiochemical procedures exist that can isolate all products, each element presents specific challenges and introduces varying degrees of systematic errors that can make inter-comparison of FPY uncertain. Although of high importance in fields such as nuclear forensics and Stockpile Stewardship, accurate information about the energy dependence of neutron induced FPY are sparse, due primarily to the lack of suitable monoenergetic neutron sources. There is a clear need for improved data, and to address this issue, a collaboration was formed between Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL) and the Triangle Universities Nuclear Laboratory (TUNL) to measure the energy dependence of FPY for {sup 235}U, {sup 238}U and {sup 239}Pu. The measurements have been performed at TUNL, using a 10 MV Tandem Van de Graaff accelerator to produce monoenergetic neutrons at energies between 0.6 MeV to 14.8 MeV through a variety of reactions. The measurements have utilized a dual-fission chamber, with thin (10-100 μg/cm2) reference foils of similar material to a thick (100-400 mg) activation target held in the center between the chambers. This method allows for the accurate determination of the number of fissions that occurred in the thick target without requiring knowledge of the fission cross section or neutron fluence on target. Following activation, the thick target was removed from the dual-fission chamber

  6. Natural Radiation in byproducts of the production of phosphoric acid; Radiacao natural em residuos gerados no processo de producao de acido fosforico

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Marcilei A. Guazzelli da; Cardoso, L.L., E-mail: marcilei@fei.edu.br [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil); Medina, N.H. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Institutlo de Fisica

    2014-07-01

    Natural radiation is the largest source of radiation exposure to which man is subject. It is formed basically by cosmic radiation and the radionuclides present in the Earth crust, as {sup 40}K and the elements of the decay series of {sup 232}Th and {sup 238}U. Phosphate ores, which constitutes the raw material for the production of phosphoric acid, have a high rate of natural radiation from the decay series of {sup 232}Th and {sup 238}U. Phosphogypsum, which is naturally radioactivity, is a by-product of the production of phosphoric acid by the wet method. For each ton of phosphoric acid it is produced about 4.5 tons of phosphogypsum. This work presents the analysis of samples collected in all stages of the manufacturing process of phosphoric acid, which generates the phosphogypsum. Gamma-ray spectrometry was used to measure the concentration of the elements of the decay series of {sup 232}Th and {sup 238}U. All analyzed samples showed a high concentration of radionuclides, promoting the need for further steps in the process in order to reduce the presence of such radionuclides in the phosphogypsum. The results indicate the radionuclide {sup 238}U has higher contribution in some samples of the intermediate stages of the process. All samples exceeded the international average range of human exposure to terrestrial gamma radiation, which is 0.3 to 1.0 mSv/year. (author)

  7. Noise characteristics of U. S. synchrotron radiation sources

    International Nuclear Information System (INIS)

    Powers, L.

    1986-01-01

    Noise characteristics of the U. S. x-ray synchrotron sources are compared in the 0--2.5-kHz region. In general, little difference is found in the characteristic frequencies of the noise on focused and unfocused beamlines of a particular source, but the magnitude and white-noise levels differ. The National Synchrotron Light Source shows the least characteristic noise and the noise that is observed is small in magnitude (2--3 times the white-noise level)

  8. Quantification of {sup 232}Th, {sup 234}U, {sup 235}U and {sup 238}U in river mollusks by magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS); Cuantificacion de {sup 232}Th, {sup 234}U, {sup 235}U y {sup 238}U en moluscos de rios por espectrometria de masas de sector magnetico con fuente de plasma acoplado inductivamente (ICP-SFMS)

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo R, D. L.; Hernandez M, H.; Romero G, E. T.; Lara A, N. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Alfaro de la T, M. C., E-mail: arevalo0591@hotmail.com [Universidad Autonoma de San Luis Potosi, Dr. Salvador Nava s/n, Zona Universitaria, 78290 San Luis Potosi, SLP (Mexico)

    2016-09-15

    The present work deals with the methodology established for the quantification of {sup 232}Th, {sup 234}U, {sup 238}U and {sup 235}U in the shell of gastropod mollusks collected in the rivers Valles, Coy and Axtla of San Luis Potosi, Mexico, which belong to the Panuco River basin; these rivers have as main source of pollution the discharge of municipal sewage, waste from small industries, agricultural and cattle residues and from natural sources. Conventional methods for measuring radio-nuclides are confronted with certain conditions related to the requirement in measurement, basically in the characterization that is related to the concepts of precision and accuracy. The analysis of the gastropod mollusk shell was performed by the Icp-SFMS technique; the main advantages of this technique lie in the isotope quantification capacity, the high precision and the low limits of detection, in this study are very important because these elements are in concentrations between ppb and ppt. This technique allowed the analysis of the samples having a complex matrix by the presence CaCO{sub 3} minimizing the interferences thanks to the ionization efficiency of the Ar plasma. For the species Pachychilus monachus were found concentrations of {sup 232}Th of 0.16-5.37 μg/g and of total U of 0.101-4.081 μg/g being this species where the highest values of total U were found. For Thiara (melanoids) tuberculata the lowest values were found among the different species ({sup 232}Th 0.61-3.61 μg/g and total U 0.006-0.042 μg/g), for Pachychilus suturalis, values of {sup 232}Th of 0.58-6.4 μg/g and for Pachychilus sp. were found between 0.26-7.62 μg/g and for total U values between 0.28-3.33 μg/g. The method offers several advantages: speed, good precision, low values of quantification limits and high sensitivity in the measurement of radio-nuclides and heavy metals. (Author)

  9. Phase radiation characteristics of an open-ended circular waveguide

    DEFF Research Database (Denmark)

    Shishkova, Anna; Pivnenko, Sergey; Kim, Oleksiy S.

    2007-01-01

    General analytical expressions are derived for the far-field amplitude and phase radiation patterns of an open-ended circular waveguide (OE-CWG) regardless of its radius or the operation frequency for the dominant and symmetric higher-order excitation modes. The derivation is based on the rigorous...... solution to the problem of diffraction at an open end of a waveguide proposed by Weinstein. The near-field amplitude and phase patterns of an OE-CWG are then calculated using the spherical wave expansion technique. The measurement of the radiation pattern of an OE-CWG was carried out to verify the validity...

  10. A characteristic scale in radiation fields of fractal clouds

    Energy Technology Data Exchange (ETDEWEB)

    Wiscombe, W.; Cahalan, R.; Davis, A.; Marshak, A. [Goddard Space Flight Center, Greenbelt, MD (United States)

    1996-04-01

    The wavenumber spectrum of Landsat imagery for marine stratocumulus cloud shows a scale break when plotted on a double log plot. We offer an explanation of this scale break in terms of smoothing by horizontal radiative fluxes, which is parameterized and incorporated into an improved pixel approximation. We compute the radiation fields emerging from cloud models with horizontally variable optical depth fractal models. We use comparative spectral and multifractal analysis to qualify the validity of the independent pixel approximation at the largest scales and demonstrate it`s shortcomings on the smallest scales.

  11. Characteristics of Smith-Purcell radiation in millimeter wavelength region

    International Nuclear Information System (INIS)

    Naumenko, G A; Potylitsyn, A P; Sukhikh, L G; Shevelev, M V; Popov, Yu; Karataev, P; Bleko, V

    2016-01-01

    Investigations of the Smith-Purcell radiation (SPR) were began with non-relativistic electron beams with some unexpected experimental results. Further the experimental investigations were performed with relativistic electron beams for application to beam diagnostics. Large discrepancy between different theoretical models significantly increases the role of experimental studies of this phenomenon. In this report we present some problems and features of experimental investigations of SPR in millimeter wavelength region. The problems of prewave zone and coherent effects are considered. The shadowing effect, focusing of radiation using a parabolic SPR target and effect of inclination of target strips were investigated with moderately relativistic electron beam. (paper)

  12. Synchrotron radiation : characteristics and application in structural studies and phase transformations of materials

    International Nuclear Information System (INIS)

    Craievich, A.F.

    1984-01-01

    The main characteristics of the synchrotron radiation for studying atomic structure and phase transformations in materials are presented. Some specific applications in alloys, glass and solids are described. (E.G.) [pt

  13. Aerodynamic characteristics and heat radiation performance of sportswear fabrics

    Science.gov (United States)

    Koga, H.; Hiratsuka, M.; Ito, S.; Konno, A.

    2017-10-01

    Sports such as swimming, speed skating, and marathon are sports competing for time. In recent years, reduction of the fluid drag of sportswear is required for these competitions in order to improve the record. In addition, sweating and discomfort due to body temperature rise during competition are thought to affect competitor performance, and heat radiation performance is also an important factor for sportswear. The authors have measured fluid force drag by wrapping cloth around a cylinder and have confirmed their differences due to the roughness of the fabric surface, differences in sewing. The authors could be verified the drag can be reduced by the position of the wear stitch. This time, we measured the heat radiation performance of 14 types of cloths whose aero dynamic properties are known using cylinders which are regarded as human fuselages, and found elements of cloth with heat radiation performance. It was found to be important for raising the heat radiation performance of sportswear that the fabric is thin and flat surface processing.

  14. Characteristics of long-term consequences of acute radiation sickness

    International Nuclear Information System (INIS)

    Kovalenko, A.N.; Belyj, D.A.; Bebeshko, V.G.

    2000-01-01

    In persons who suffered from acute radiation sickness (ARS) as a result of the Chernobyl accident in course of time there are revealed the stochastic and non-stochastic effects of irradiation both in 'critical' and 'non-critical' organism systems. It is connected with maintenance of somatic mutation high level and steady changes in membranes subcellular structures, biomolecules as well as metabolic disturbances. Stable changes of hemopoietic and immune system indexes have to be considered as pre-pathological status with high hazard of stochastic effects dev