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Sample records for characteristics 238u 232th

  1. The learning of the evolution and temporary characteristics of the decay nuclei 14C, 238U, 232Th, 40K, 87Rb

    International Nuclear Information System (INIS)

    Quantum-mechanical method, which was proposing earlier for the theoretical description of the resonance scattering of the γ-quantum, was generalizing with Doppler effect using. New algorithm for the definition of the characteristic functions for the energy distribution, decay probability and decay functions elaborated. It gives possibility more precise estimate temporary characteristics of the nuclei chronometers and to define a number of the steps of the γ-absorption γ-emission in the decay process. It is give the quantum- mechanical ground of the necessity of revision of the temporary characteristics of the nuclei-chronometers. The calculations have been doing for the concrete case decay of exited nuclei 14C, 238U, 232Th, 40K, 87Rb under room temperature taking into account Doppler effect and without it. 4 refs., 1 tab., 6 figs

  2. Delayed neutron and delayed photon characteristics from photofission of 232Th, 235,238U, and 237Np with endpoint Bremsstrahlung photons in the giant dipole resonance region

    Science.gov (United States)

    Doré, D.; Dighe, P. M.; Berthoumieux, E.; Laborie, J.-M.; Ledoux, X.; Macary, V.; Panebianco, S.; Ridikas, D.

    2009-10-01

    A renewed interest in photonuclear reactions was stimulated by applications as radioactive ion beam production, irradiation stations by high energy photons, shielding of electron accelerators, etc. Today, a particular attention is paid to the non-destructive characterization of waste barrels and the detection of nuclear materials, both based on photofission process and the associated delayed neutron (DN) and delayed photon (DP) emissions. The need of accurate and complete data for DN and DP yields and time characteristics of actinides was the motivation for an experimental campaign, started in 2004. In this paper, the experimental setup and the data analysis method will be presented and the modeling work will be described. Experimental results for DN and DP characteristics will be compared to calculations in the case of photofission of 232Th, 235,238U, and 237Np.

  3. Photo fission cross-section of 232Th, 238U and 237Np

    International Nuclear Information System (INIS)

    In the present work, photo fission cross-section of 232Th, 238U and 237Np evaluated with the help of fission fragment angular distribution measurements by using Bremsstrahlung radiation from 7.4 MeV to 9.0 MeV have been carried out by employing high efficiency SSNTD technique

  4. Radiationless transition probabilities in muonic 208Pb, 232Th, and 238U

    International Nuclear Information System (INIS)

    The probabilities for non-radiative (n.r.) excitations Pn.r. in the muonic nuclides 208Pb, 232Th, and 238U have been determined for (μ-, γγ)-measurements by comparing the intensities of muonic X-ray transitions in single and coincidence spectra. The value of Pn.r. (3p→1s), measured for the first time, is about 90% for the actinides 232Th and 238U, but only about 8% for 208Pb. The value of Pn.r. (3d→1s) is found to be 10% for 233Th, 13% for 238U, and about 4% for 208Pb. For 208Pb a vanishing strength of the n.r. decay of the 2p-level is found, while for 232Th and for 238U n.r. strengths of about 20% and 26%, respectively, are observed. By regarding two subcomplexes of the 2p→1s transitions leading to different mean excitation energies the n.r. transition probabilities were found to be different for 238U only, 21.6% and 31.1%, respectively. (orig.)

  5. 232Th and 238U neutron emission cross section calculations and analysis of experimental data

    International Nuclear Information System (INIS)

    In this study, pre-equilibrium neutron-emission spectra produced by (n,xn) reactions on nuclei 232Th and 238U have been calculated. Angle-integrated cross sections in neutron induced reactions on targets 232Th and 238U have been calculated at the bombarding energies up to 18 MeV. We have investigated multiple pre-equilibrium matrix element constant from internal transition for 232Th (n,xn) neutron emission spectra. In the calculations, the geometry dependent hybrid model and the cascade exciton model including the effects of pre-equilibrium have been used. In addition, we have described how multiple pre-equilibrium emissions can be included in the Feshbach-Kerman-Koonin (FKK) fully quantum-mechanical theory. By analyzing (n,xn) reaction on 232Th and 238U, with the incident energy from 2 Me V to 18 Me V, the importance of multiple pre-equilibrium emission can be seen cleady. All calculated results have been compared with experimental data. The obtained results have been discussed and compared with the available experimental data and found agreement with each other

  6. Distribution of 137Cs, 40K, 238U and 232Th in soils from Northern Venezuela

    International Nuclear Information System (INIS)

    More than one hundred undisturbed soil samples form Northern Venezuela and the islands of Margarita and Los Roques have been analyzed for 137Cs, 40K, 238U and 232Th by γ-ray spectroscopy. The specimens were taken from between 5-10 cm below the earth's surface. Thus, they are valid not only for the 137Cs deposition studies but also for the estimation of the natural γ-ray dose from primordial radionuclides that form the terrestrial component. The concentrations of 40K was directly determined from its 1461 keV γ-ray, while those of 137Cs, 238U and 232Th were performed using a γ-ray from one of their daughter radionuclides: the 661 keV γ-ray of 137mBa for 137Cs, the 1760 keV γ-ray of 214Bi for 238U and the 2620 keV γ-ray of 208Tl for 232Th. Finally, the concentration values were compared with those of global estimates. (author) 15 refs.; 4 figs.; 2 tabs

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

    International Nuclear Information System (INIS)

    Differential-neutron-emission cross sections of 232Th, 233U, 235U, 238U, 239Pu and 240Pu 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. 232Th, 233U, 235U and 238U inelastic-scattering values, poor agreement is observed for 240Pu, and a serious discrepancy exists in the case of 239Pu

  8. 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.)

  9. Studies of positron electron pair production in {sup 238}U + {sup 232}Th

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Back, B.B.; Betts, R.R. [and others

    1995-08-01

    Following the non-observation of sharp sum-energy lines in our earlier {sup 238}U + {sup 181}Ta measurements, it was decided to pursue measurements of the {sup 238}U + {sup 232}Th system which, in the previously published work, showed the most striking evidence for near-equal-energy back-to-back pairs leading to sharp sum-energy lines. Following the refurbishing of the APEX silicon arrays and extensive tests of the rotating target wheel assembly, a major positron run took place in November 1994. Rolled 1-mg/cm{sub 2} {sup 232}Th targets were bombarded with 5.95-MeV/u {sup 238}U. The target rotation allowed up to 2 pnA of beam to be used without serious deterioration of the targets. Over 300,000 pairs were accumulated, representing an order-of-magnitude improvement in statistics over the previously published results. Preliminary analysis shows no evidence for the sharp lines at a cross section level orders of magnitude below those previously reported. The analysis of these data is currently being completed in preparation for publication.

  10. Prompt γ-rays from the Fast Neutron Induced Fission on 235,238U and 232Th

    Science.gov (United States)

    Lebois, M.; Wilson, J. N.; Halipré, P.; Leniau, B.; Matea, I.; Oberstedt, A.; Oberstedt, S.; Verney, D.

    Preliminary results from the first experiment using the LICORNE neutron source at the IPN Orsay are presented. Prompt fission gamma rays from fast-neutron induced fission of 238U, 232Th and 235U were detected. Thick samples of around 50 g of 238U and 232Th are used for the first part of the experiment. An ionisation chamber containing ∼ 10 mg samples of 238U and 235U to provide a fission trigger is used for the second part of the experiment. Gamma rays have been detected using 17 high efficiency BaF2 detectors and 6 LaBr3 scintillator detectors.

  11. Natural activities of {sup 238}U, {sup 232}Th and {sup 40}K in building materials

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, N. [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    1999-05-01

    Seven kinds of building materials were analysed for {sup 238}U, {sup 232}Th and {sup 40}K using a direct {gamma}-counting method. The activity concentrations measured for {sup 238}U (30-448 Bq kg{sup -1}) and {sup 40}K (328-7541 Bq kg{sup -1}) were greater than the world average activity for soil (25 and 370 Bq kg{sup -1}, respectively) for all building materials analysed, while the activity concentrations of {sup 232}Th were found to exceed the average of 25 Bq kg{sup -1} (soil) for red-clay brick (51 Bq kg{sup -1}) and ceiling asbestos sheet materials (162 Bq kg{sup -1}). The calculated Ra equivalent activities (Ra{sub eq}) for all materials are higher than the world average value for soil (89 Bq kg{sup -1}). For red-clay brick and ceiling asbestos, the Ra{sub eq} values are found to exceed the limit of 370 Bq kg{sup -1}, equivalent to a {gamma}-dose of 1.5 mSv yr{sup -1}. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. 238 U, 232 Th and 40 K in wheat flour samples of Iraq markets

    Directory of Open Access Journals (Sweden)

    A. A.

    2014-09-01

    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.

  13. 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.

  14. Radioactivity of Natural Nuclides (40K, 238U, 232Th, 226Ra) in Coals from Eastern Yunnan, China

    OpenAIRE

    Xin Wang; Qiyan Feng; Ruoyu Sun; Guijian Liu

    2015-01-01

    The naturally occurring primordial radionuclides in coals might exhibit high radioactivity, and can be exported to the surrounding environment during coal combustion. In this study, nine coal samples were collected from eastern Yunnan coal deposits, China, aiming at characterizing the overall radioactivity of some typical nuclides (i.e., 40K, 238U, 232Th, 226Ra) and assessing their ecological impact. The mean activity concentrations of 238U, 232Th, 40K and 226Ra are 63.86 (17.70–92.30 Bq· kg-...

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

    International Nuclear Information System (INIS)

    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 232Th and 238U 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 232Th, 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. 238U, 232TH, AND 222RN concentration measured in various traditional medicinal plant preparation using nuclear track detectors

    International Nuclear Information System (INIS)

    Full text: 238U, 232Th, 222Rn concentrations were measured inside traditional medicinal plants preparations widely used by patients in classic and modern phyto therapy by using a technique based on the use of solid state nuclear track detectors. The intakes of these radionuclides have been determined for adult patients from the ingestion of the studied medical preparations. The influence of mass intake as well as pollution on the contents of the considered radionuclides was investigated. The resulting radiation doses to adult patients from the ingestion of the traditional medical preparations were evaluated.

  17. Quantification of transfer of {sup 238}U, {sup 226}Ra, {sup 232}Th, {sup 40}K and {sup 137}Cs in mosses of a semi-natural ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Dragovic, S., E-mail: sdragovic@inep.co.r [Institute for the Application of Nuclear Energy - INEP, University of Belgrade, Banatska 31b, 11080 Belgrade (Serbia); Mihailovic, N. [Institute for the Application of Nuclear Energy - INEP, University of Belgrade, Banatska 31b, 11080 Belgrade (Serbia); Gajic, B. [Faculty of Agriculture, Institute of Land Management, Laboratory of Soil Physics, University of Belgrade, Nemanjina 6, 11081 Belgrade (Serbia)

    2010-02-15

    There is a lack of appropriate data on transfer of some radionuclides on many terrestrial biota groups. To expand the available data concentration ratios of {sup 238}U, {sup 226}Ra, {sup 232}Th, {sup 40}K and {sup 137}Cs in mosses are presented in this paper. The relationship between concentration ratios of radionuclides and physicochemical characteristics of the underlying soil was also investigated. The data on concentration ratios obtained here will provide a useful addition to the currently used database of transfer parameters, particularly for natural radionuclides.

  18. 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)

  19. Primordial radioactivity ((238)U, (232)Th and (40)K) measurements for soils of Ludhiana district of Punjab, India.

    Science.gov (United States)

    Badhan, K; Mehra, R

    2012-11-01

    The aim of the present work was to study the activity concentration and absorbed gamma dose rates due to primordial radionuclides ((238)U, (232)Th and (40)K) for the soil of different villages of Ludhiana district of Punjab, India using a high-purity germanium detector based on high resolution gamma-ray spectrometry. The average activity concentrations of (238)U, (232)Th and (40)K in the soil samples have been found to be 28.58, 50.95 and 569.59 Bq kg(-1), respectively, which gives the total gamma dose rate contribution of 68.50 nGy h(-1). To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the external hazard index, the absorbed dose rate and the effective dose rate have been calculated. The calculated radium equivalent activity values are on the lower side of the recommended safe limit value of 370 Bq kg(-1) by Organization of Economic and Control Department. The calculated value of external health hazard index is lower than unity. PMID:22899219

  20. Radioactivity of 238U, 232Th, 40K, and 137Cs and assessment of depleted uranium in soil of the Musandam Peninsula, Sultanate of Oman

    OpenAIRE

    SALEH, Ibrahim Hindawy

    2012-01-01

    238U, 232Th, 40K, and 137Cs radioactivities were determined in soil samples collected from the Musandam Peninsula, Sultanate of Oman, using a high resolution gamma-ray spectroscopy system. In addition, total uranium was measured in selected soil samples by inductively coupled plasma optical emission spectroscopy (ICP-OES). The averages of radioactivity levels in the soil for 238U, 232Th, and 40K were 14.42 Bq kg-1, 9.95 Bq kg-1, 158.21 Bq kg-1, and 2770 Bq m-2 for 137Cs, respectively...

  1. 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)

    Thorium-232 and 238U contents in four food groups were measured by inductively coupled plasma mass spectrometry (ICP-MS). Daily intakes of 232Th and 238U 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

  2. 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)

  3. The activity concentrations of 40K, 226Ra, 232Th, 238U and 7Be in moss from spas in eastern Serbia in the period 2000-2012

    Directory of Open Access Journals (Sweden)

    Čučulović Ana

    2014-01-01

    Full Text Available In this work we present the activity concentrations of natural radionuclides 40K, 226Ra, 232Th, 238U and 7Be in mosses. One hundred and sixty-seven moss samples were collected between 2001 and 2012 from the territory of the Sokobanja, Banja Jošanica and Gamzigradska Banja spas. They were classified into 23 species. The activity concentrations (Bq/kg in moss from Sokobanja spa were: 40K 25-427; 226Ra 0.3-36; 232Th 1.0-37; 238U 0.4-28 and 7Be 29-210; from Banja Jošanica spa they were: 40K 90-242; 226Ra 2.4-11.7; 232Th 2.0-12.7; 238U 1.6-11.3 and 7Be 142-212; Gamzigradska Banja spa: 40K 95-351; 226Ra 8.0-21; 232Th 5.1-19; 238U 6.7-18 and 7Be 20-144. The activity concentrations of dominant natural radionuclides (potassium, radium, thorium and uranium in the moss samples were within the usual ranges for the territory of Serbia. [Projekat Ministarstva nauke Republike Srbije, br. III 43009

  4. 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...

  5. 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)

    The concentration of naturally occurring radionuclides 232Th, 238U 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 238U and 232Th 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 238U and 232Th 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: ► 232Th, 238U 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 232Th and 238U in high rainfall area was found to be 3.4 and 2.0 μg respectively.

  6. 230Th, 232Th and 238U determinations in phosphoric acid fertilizer and process products by ICP-MS

    International Nuclear Information System (INIS)

    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, 230Th, 232Th and 238U were directly determined after dilution, except 230Th 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 230Th, and ICP-OES and spectrophotometry with arsenazo III for elementary uranium and thorium determinations. (author)

  7. A beta-alpha coincidence counting system for measurement of trace quantities of 238U and 232Th in aqueous samples at the Sudbury Neutrino Observatory.

    Science.gov (United States)

    Dawson, M.; Doucas, G.; Fergani, H.; Jelley, N. A.; Majerus, S.; O'Keeffe, H. M.; Peeters, S. J. M.; Perry, C.

    2016-08-01

    The Sudbury Neutrino Observatory experiment was built to measure the total flux of 8B solar neutrinos via the neutral current disintegration deuterium nuclei. This process can be mimiced by daughter isotopes of 232Th and 238U which can photodisintegrate the deuterium nucleus. Measurement of the concentration of such radioisotopes in the heavy water was critical to the success of the experiment. A radium assay technique using Hydrous Titanium Oxide coated filters was developed for this purpose and it was used in conjunction with a delayed beta-alpha coincidence counting system. The design, calibration and operation of this counting system are described in this paper. The counting efficiency for 232Th (224Ra) and 238U (226Ra) were measured to be 50 ± 5% and 62 ± 7%

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

    International Nuclear Information System (INIS)

    A reconnaissance study has been made of the distribution of 238U, 232Th, 40K and 137Cs 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 40K (range from 146 to 500 Bq kg-1), 137Cs (from 5 to 20 Bq kg-1), 238U (from 21 to 65 Bq kg-1) and 232Th (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

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

    International Nuclear Information System (INIS)

    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 238U, 234U, 230Th, 22'6Ra, 210Pb and 210Po, members from the 238U decay series, and the radionuclides 232Th and 228Ra members of the 232Th 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 210Po determination, and gross alpha and beta counting, 228Ra, 226Ra and 210Pb 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 226Ra, 228Ra, 210Pb, and 210Po, were determined in most parts of the plants

  10. Determination of 238U, 232Th and 40K activity concentrations in riverbank soil along the Chao Phraya river basin in Thailand

    International Nuclear Information System (INIS)

    The activity concentrations of 238U, 232Th and 40K in riverbank soil along the Chao Phraya river basin was determined through gamma-ray spectrometry measurements made using a hyper-pure germanium detector in a low background configuration. The ranges of activity concentrations of 238U, 232Th and 40K were found to be 13.9 ↔ 76.8, 12.9 ↔ 142.9 and 178.4 ↔ 810.7 Bq kg−1, respectively. The anthropogenic radionuclide, 137Cs, was not observed in statistically significant amounts above the background level in the current study. The absorbed gamma dose rate in air at 1 m above the ground surface, the outdoor annual effective dose equivalent, the values of the radium equivalent activity and the external hazard index associated with all the soil samples in the present work were evaluated. The results indicate that the radiation hazard from primordial radionuclides in all soil samples from the area studied in this current work is not significant. - Highlights: • Radioactivity in surface soils from the Chao Phraya river basin in Thailand is evaluated. • Gamma-ray spectrometric analysis is to identify decays associated with 226Ra, 232Th and 40K. • The results provide baseline measurements for any changes in future radioactivity levels

  11. Simulation smuggling study for shielded sources of 235U, 238U, 232Th, 137Cs and 60Co by using γ-detection

    International Nuclear Information System (INIS)

    This work deals with gamma detection of shielded sources of 235U, 238U, 232Th, 137Cs and 60Co by using HpGe and NaI detectors through their main characteristic energies; 185.7 keV, (63, 1001), (583 and 911), 661.6 and (1173 and 1332) KeV respectively. These radioactive sources were individually hidden in containers of aluminum (Al), iron (Fe) and cupper (Cu) of different thicknesses; 3, 6, 9, 12, 15, 18 mm. Thin containers of lead (Pb) were also used with the same sources. The attenuation factor (I/I0), the ratio of radiation intensity with and without container or shield, was calculated for all the investigated γ-energies. The relationship between the attenuation factor and the studied thicknesses of the containers was given, depicted and discussed. Detection of the mixed sources shielded by different materials of different thicknesses was also carried out by using PDR-77 survey meter. The radiation levels were found to be within the natural background at 65cm distance from the shielded sources. Telescopic arm carrying 2x2 NaI and radiometer was also used. Generally, It can be concluded that smuggling of radioactive materials of low radioactivity can be done without detection by hiding them in containers or within scrap of Cu, Fe or even Al rather than using the conventional heavy lead shield. (author)

  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. Determination of radioactivity level of 238U, 232Th and 40K in surface medium in Zhuhai city by in-situ gamma-ray spectrometry

    International Nuclear Information System (INIS)

    A gamma-ray spectrometry survey with NaI(Tl) (φ75mm x 75mm) has been performed on a large scale to determine the distribution of 40K, 238U and 232Th in soil and rocks in Zhuhai, a southern Chinese city located in Guangdong Province. The survey sampled 970 sites which covered an area of more than 100 km2. The average activities of 40K. 238U and 222Th were found 655±338, 85.8±31.6, and 159.8±49.0 Bq·kg-1 in soil or cement of pavement in the urban area; 832±455, 87.3±41.6, and 179.3±40.7 Bq·kg-1 in weathered granite; 634±76.8, 35.2±14.6 and 70.2±18.6Bq·kg-1 in the Quaternary sediments in Doumen District. The average 232Th activity (159.8±49.0 Bq·kg-1) is above the average in both China (49 Bq·kg-1) and the world (30 Bq·kg-1). Terrestrial air-absorbed dose rates calculated from the above activities are 85.08±15.63, 183.33±40.80 nGy·h-1 respectively over the Quaternary sediments and weathered granite, and 163.49±30.15 nGy·h-1 in the urban area. The average calculated air-absorbed dose rate is about 12.63% larger than the value measured by a portable plastic scintillator dosemeter. The 40K, 238U and 232Th activities in surface medium are mainly originated from biotite granites, as indicated by a strong correlation between the radioactivity level and geological lithology in the surveyed area. (author)

  14. Comparison of the (p,xn) cross sections from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Y.Y.; Zhou, M.L.

    1982-01-01

    We have measured absolute cross sections for (p,xn) reactions (x ranges from 0 to 8) from /sup 238/U, /sup 235/U, and /sup 232/Th targets irradiated with 200-MeV protons at the Brookhaven AGS Linac injector. Chemical yields were determined by using /sup 239/Np and /sup 233/Pa as tracers. Yield patterns obtained in this work can be compared to the experimental results and theoretical calculations from earlier work, and they are consistent within the framework of intranuclear cascade followed by neutron evaporation and fission competition.

  15. Daily intake of /sup 234,235,238/U, /sup 228,230,232/Th and /sup 226,228/Ra by New York City residents

    International Nuclear Information System (INIS)

    The daily intake of long-lived alpha-emitting members of the U, Th and Ac series by New York City residents has been estimated from measurements of diet, water and air samples. The total daily intakes from inhalation, food and water consumption in mBq are 18 (234U), 0.7 (235U), 16 (238U), 6 (230Th), 4 (232Th) and 52 (226Ra). From this, we infer that the total daily intakes of 228Th and 228Ra are 4 and 35 mBq, respectively

  16. 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.

  17. Measurement of double-differential neutron emission cross sections of 238U, 232Th and 12C for 18 MeV neutrons

    International Nuclear Information System (INIS)

    Double-differential neutron emission cross sections of 238U, 232Th and 12C have been measured for 18-MeV incident neutrons using the neutron time-of-flight technique and Tohoku University 4.5MV Dynamitron accelerator as a pulsed neutron generator. In the experiment, energy resolution of the spectrometer was improved by employing a newly developed post-acceleration beam-chopper and by adjustment of timing property of the neutron detector. Measurements were made at laboratory angles between 30- and 145- deg., and data were obtained for secondary neutrons between 0.8 and 18 MeV. In the data processing, a care was taken for the data correction for the effects of parasitic neutrons associated with primary neutrons; the correction proved to be of special importance in the present measurement. We compared the data obtained in the present experiment with the evaluated data, JENDL-3 and ENDF/B-IV (B-V for 12C), and discussed the origin of the discrepancies. The anisotropy observed for secondary neutrons from 238U and 232Th was found to be reproduced by Kalbach-Mann systematics on the assumption of isotropy of fission neutrons. The experimental results for 12C showed marked discrepancies concerning the scattering cross sections and neutron spectrum in the continuum region. (author)

  18. 238U series isotopes and 232Th in carbonates and black shales from the Lesser Himalaya: implications to dissolved uranium abundances in Ganga-Indus source waters.

    Science.gov (United States)

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

    2003-01-01

    238U 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 microg 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 (approximately 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 microg g(-1). Based on this concentration, supply of U from at least approximately 50 mg of black shales per liter of river water is needed to balance the average river water U concentration, 1.7 microg L

  19. 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

  20. Alpha Spectrometry for Determination of 238U, 235U, 234U, 232Th and 230Th in Soil Sample

    International Nuclear Information System (INIS)

    Monitoring of radioactivity in soil around the nuclear power plant is important. In this study, the radioactivity of uranium and thorium isotopes in soil (NIST SRM 2709a) is analyzed by alpha spectrometry. Alpha spectrometry is a powerful analytical tool for the identification and assay of the alpha-emitting sources primarily due to its high counting efficiency, high sensitivity and low price. Another aim of this study is to present the extent of disequilibrium of 238U/234U and 238U/230Th. The soil sample was decomposed by a fusion technique, and the source for the alpha spectrometry was prepared by electrodeposition of an alpha-emitting nuclides onto a metallic substrate. In this work, uranium and thorium isotopes were chemically separated from a soil sample (NIST SRM 2709a) using chromatographic columns, and electrodeposited on a stainless steel disc to measure the radioactivity concentration of the isotopes with an alpha spectrometer. The ratio of 238U/234U for the soil sample was ca. 1 which is considered to be in secular equilibrium

  1. 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)

    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 226Ra, 238U and 232Th in water, suspended matter, distribution coefficients and Th/U mass rations. (author)

  2. Daily intakes of 238U, 234U, 232Th, 230Th, 228Th and 226Ra in the adult population of central Poland

    Energy Technology Data Exchange (ETDEWEB)

    Pietrzak-Flis, Z.; Rosiak, L.; Suplinska, M.M.; Chrzanowski, E.; Dembinska, S. [Central Laboratory for Radiological Protection, Konwaliowa 7, 03-194 Warsaw (Poland)

    2001-06-12

    Activity concentration of the uranium and thorium series radionuclides was determined in foodstuffs and drinking water in central Poland. Annual and daily intake for the adult population was estimated from the concentrations determined and average annual consumption of food and water. The daily intakes (in mBq) were 22.1 (238U), 26.5 (234U), 2.38 (232Th), 4.06 (230Th), 11.2 (228Th) and 42.2 (226Ra). The intake of uranium isotopes occurred mainly with water; the main intake of thorium isotopes was with animal products, vegetables, cereals and potatoes, whereas 226Ra entered mainly with animal products, cereals and vegetables. From the intake and dose coefficients, the annual effective doses for the ingested radionuclides were calculated. The annual effective dose was 5.95 {mu}Sv, of which 72.4% originated from 226Ra.

  3. Experimental Neutron-Induced Fission Fragment Mass Yields of 232Th and 238U at Energies from 10 to 33 MeV

    CERN Document Server

    Simutkin, V D; Blomgren, J; Österlund, M; Bevilacqua, R; Ryzhov, I V; Tutin, G A; Yavshits, S G; Vaishnene, L A; Onegin, M S; Meulders, J P; Prieels, R

    2013-01-01

    Development of nuclear energy applications requires data for neutron-induced reactions for actinides in a wide neutron energy range. Here we describe measurements of pre-neutron emission fission fragment mass yields of 232Th and 238U at incident neutron energies from 10 to 33 MeV. The measurements were done at the quasi-monoenergetic neutron beam of the Louvain-la-Neuve cyclotron facility CYCLONE; a multi-section twin Frisch-gridded ionization chamber was used to detect fission fragments. For the peak neutron energies at 33, 45 and 60 MeV, the details of the data analysis and the experimental results have been published before and in this work we present data analysis in the low-energy tail of the neutron energy spectra. The preliminary measurement results are compared with available experimental data and theoretical predictions.

  4. 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)

    Time-of-flight measurements of neutron induced fission cross section ratios for 232Th, /sup 235,238/U, 237Np, and 239Pu, 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

  5. Search for quasifission in 12C + 238U and 18O + 232Th reactions at near and sub-barrier energies

    International Nuclear Information System (INIS)

    The main motivation of this present work is to study the onset of quasifission process in the fissility region > 0.8. It was observed that angular distribution of fission fragments produced in reaction in this fissility region showed anomalously large anisotropies at subbarrier energies as compared to SSPM, implying presence of pre-equilibrium fission. Here, mass-angle correlation studies of 12C + 238U and 18O + 232Th reactions has been reported, forming same compound nucleus 250Cf (Fissility = 0.86), at similar excitation energy and angular momentum. The measurements were carried out in the energy range Ecm /Vb ∼ 0.88 - 1.1, where Ecm is the energy in centre of mass frame and Vb is the Coulomb barrier

  6. Determination of environmental radioactivity (238U, 232Th and 40K) and indoor natural background radiation level in Chennai city (Tamilnadu State), India.

    Science.gov (United States)

    Babai, K S; Poongothai, S; Punniyakotti, J

    2013-01-01

    An extensive study on the determination of the natural radioactivity ((238)U, (232)Th and (40)K) levels in soil samples of Chennai city, India has been undertaken and the results of the same are compared with the levels reported in other Indian cities as well as other parts of the world. The radioactivity content in the soil samples, the absorbed dose rate, annual effective dose equivalent, radium equivalent activity, internal and external hazard indices were calculated and compared with UNSCEAR 2000 recommended values. In addition to the above, mapping of indoor natural background gamma radiation levels has been made using thermo luminescent dosemeters throughout Chennai city and the same are reported. PMID:22847868

  7. The dietary intake of 238U, 234U, 230Th, 232Th, 228Th and 226Ra from food and drinking water by inhabitants of the Walbrzych region

    International Nuclear Information System (INIS)

    Intake with food and water of the natural radionuclides of the uranium and thorium series was determined for adult population of the south-western region in Poland, where in the 1950-ies an exploration of uranium ore was conducted. Concentration of the radionuclides was determined in food products and drinking water and their annual intake was estimated on the basis of the average annual consumption. The intake of 238U, 234U and 230Th occurred mainly with water (33% to 68%), whereas the intake of 232Th, 228Th and 226Ra was mainly with vegetables, potatoes, milk and flour. From the intake and dose coefficients the annual effective doses from the ingested radionuclides were calculated. The total dose was 5.6μSv, of which 74% originated from 226Ra. (author)

  8. Daily intakes of 238U, 234U, 232Th, 230Th, 228Th and 226Ra in the adult population of central Poland

    International Nuclear Information System (INIS)

    Activity concentration of the uranium and thorium series radionuclides was determined in foodstuffs and drinking water in central Poland. Annual and daily intake for the adult population was estimated from the concentrations determined and average annual consumption of food and water. The daily intakes (in mBq) were 22.1 (238U), 26.5 (234U), 2.38 (232Th), 4.06 (230Th), 11.2 (228Th) and 42.2 (226Ra). The intake of uranium isotopes occurred mainly with water; the main intake of thorium isotopes was with animal products, vegetables, cereals and potatoes, whereas 226Ra entered mainly with animal products, cereals and vegetables. From the intake and dose coefficients, the annual effective doses for the ingested radionuclides were calculated. The annual effective dose was 5.95 μSv, of which 72.4% originated from 226Ra

  9. 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

    Indian Academy of Sciences (India)

    M A Misdaq; A Mortassim

    2009-11-01

    238U and 232Th concentrations as well as 222Rn and 220Rn -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 238U, 232Th, 222Rn and 220Rn 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 238U, 232Th and 222Rn intakes by Moroccan adults from the consumption of honey were assessed. The influence of the nature of soil and plant on the 238U and 232Th contents of the studied honey samples was investigated. These measurements were completed by an investigation of the 238U 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 238U, 232Th and 222Rn in the honey samples studied. Committed equivalent doses due to the annual intake of 238U, 232Th and 222Rn 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 238U, 232Th and 222Rn from the ingestion of natural honey by the Moroccan rural population was found to be equal to 0.64 Sv y-1 .

  10. 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.

  11. 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)

  12. Non-destructive determination of 235U, 238U, 232Th and 40K concentrations in various consumed nuts and their implication on radiation dose levels to the human body

    International Nuclear Information System (INIS)

    The naturally occurring radionuclides of 238,235,234U,232Th and 40K and their daughter products are a potential source of radiation found in food. We have determined these five radiation sources in five popular consumed nuts. We used the following neutron activation analysis reactions of 238U(n,γ)239U, 232Th(n,γ)233Th and 41K(n,γ)42K to determine 238U and 232Th and 40K, respectively. Using known activity ratios of uranium stable isotopes we determined the activity of 234,235U, while 40K was found by the determined concentrations of 41K in the nuts. While the radiation doses are small we have established a reliable methodology to determine these radionuclides in typical edible nuts. (author)

  13. 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)

    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 238U and 232Th 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

  14. {sup 230}Th, {sup 232}Th and {sup 238}U determinations in phosphoric acid fertilizer and process products by ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Marcos R.L. do; Guerreiro, Luisa M.R.; Bonifacio, Rodrigo L.; Taddei, Maria H.T., E-mail: pmarcos@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas

    2015-07-01

    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, {sup 230}Th, {sup 232}Th and {sup 238}U were directly determined after dilution, except {sup 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 {sup 230}Th, and ICP-OES and spectrophotometry with arsenazo III for elementary uranium and thorium determinations. (author)

  15. 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).

  16. 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...

  17. Vertical and horizontal distribution of radionuclides (232Th, 238U and 40K) in sediment from Manjung coastal water area Perak, Malaysia

    International Nuclear Information System (INIS)

    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)

  18. Influence of different data tables on neutron induced reactions in quasi-infinite 238U and 232Th targets irradiated by protons with relativistic energy

    Science.gov (United States)

    Zhivkov, P.; Stoyanov, Ch; Tyutyunnikov, S.; Furman, W.

    2016-06-01

    The last decade saw the emergence of various theoretical analysis and developments of ADS (Accelerator Driving System). Different transport codes, nuclear models and nuclear cross sections have been used to predict and estimate the properties of ADS. The energy of the proton beam is supposed to range between 1 and 1.5 GeV, but some analyses suggest higher energy - up to 10 GeV. The recent papers examine the influence of the nuclear models on neutron induced reactions (n,f), (n,g), (n,xn), (n,el.) and (n,inel.). The experimental set-ups and the presumable ADS constructions consist of thousands of segments and details for example project Myrrha, Belgum [1]. The calculation of the above reactions depends on the neutron spectrum in each segment. There is a considerable difference in the size of these segments in ADS, which makes the estimation of the influence of the nuclear models and the cross sections on the integral number of neutron induced reactions more difficult. This article considers the influence of different cross section data tables on neutron induced reactions in 238U or 232Th targets. One nuclear model describing the high energy part of the nuclear interaction and various cross section data tagble (ENDF, ENDL, TENDL2014 and etc.) are used. All particles generated in the nuclear interaction process deposit their energy in the target volume. MCNP 6.1 transport code was used.

  19. 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})

  20. Measurement of 238U and 232Th in Petrol, Gas-oil and Lubricant Samples by Using Nuclear Track Detectors and Resulting Radiation Doses to the Skin of Mechanic Workers.

    Science.gov (United States)

    Misdaq, M A; Chaouqi, A; Ouguidi, J; Touti, R; Mortassim, A

    2015-10-01

    Workers in repair shops of vehicles (cars, buses, truck, etc.) clean carburetors, check fuel distribution, and perform oil changes and greasing. To explore the exposure pathway of (238)U and (232)Th and its decay products to the skin of mechanic workers, these radionuclides were measured inside petrol, gas-oil, and lubricant material samples by means of CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs), and corresponding annual committed equivalent doses to skin were determined. The maximum total equivalent effective dose to skin due to the (238)U and (232)Th series from the application of different petrol, gas-oil, and lubricant samples by mechanic workers was found equal to 1.2 mSv y(-1) cm(-2). PMID:26313584

  1. 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.

  2. Use of electrodeposition for sample preparation and rejection rate prediction for assay of electroformed ultra high purity copper for 232Th and 238U prior to inductively coupled plasma mass spectrometry (ICP/MS)

    International Nuclear Information System (INIS)

    The search for neutrinoless double beta decay in 76Ge has driven the need for ultra-low background Ge detectors shielded by electroformed copper of ultra-high radiopurity (232Th and 238U into the plating bath simulates low purity copper and allows for the calculation of the electrochemical rejection rate of thorium and uranium in the electroplating system. This rejection value will help to model plating bath chemistry. (author)

  3. 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)

    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.)

  4. Determination of 40K, 232Th and 238U activity concentrations in ambient PM2.5 aerosols and the associated inhalation effective dose to the public in Jeddah City, Saudi Arabia

    International Nuclear Information System (INIS)

    Natural radioactivity of soil samples has been studied in many countries of the Arabian Peninsula, including Saudi Arabia. Radiological indices based on soil radioactivity have been widely used in these studies. However, there are no available data about natural radioactivity of fine aerosol particles in such countries. The objective of this study is to determine the activity concentrations of 40K, 232Th and 238U in airborne PM2.5 and the associated internal inhalation radiation dose to the public in Jeddah City, Saudi Arabia. Twenty-four air samples in four locations throughout Jeddah were collected and analyzed for PM2.5 and the associated K, Th and U. The activity concentrations of the isotopes 40K, 232Th and 238U were calculated. High atmospheric PM2.5 concentrations (mean: 50.81 ± 34.02 μg/m3) were found. The natural radioactivity associated with PM2.5 due to the isotopes 40K, 232Th and 238U were 301.8 ± 76.1, 11.8 ± 4.2 and 10.8 ± 3.4 Bq/kg, respectively, and the Raeq was calculated as 44.9 ± 14.0 Bq/kg. The inhalation annual effective radiation dose to the public due to natural isotopes of the airborne PM2.5 was in the range 15.03–58.87 nSv/year, depending on the age group. Although these dose values were associated with the PM2.5 fraction only, they were higher than the world references values in air reported in the UNSCEAR, 2000 report. - Highlights: • High airborne PM2.5 concentrations over 4 months (24 samples) were found in Jeddah. • The mean activity concentrations of 40K, 232Th and 238U were assessed in PM2.5. • Effective inhalation dose due to 40K, 232Th and 238U was 59 nSv/year for adults. • Effective inhalation dose was higher than the world reference values in air. • Studying the inhalation dose due to other radioisotopes in PM2.5 is recommended

  5. Development of an analytical method for the determination of U-238, U-234, Th-232, Th-230, Th-228, Ra-228, Ra-226, Pb-210 and Po-210 and its application on environmental samples

    International Nuclear Information System (INIS)

    A comparison between the environmental impact by nuclear facilities with the burden suffered from natural radioactivity calls for studying the long-lived radionuclides of the U-238 and Th-232 decay series U-238, U-234, Th-232, Th-230, Th-228, Ra-228, Ra-226, Pb-210 and Po-210. This work describes the development of a fast isotope dilution analysis method allowing to separate with one sample solution U, Th, Ra, Pb and Po both from each other and, at the same time, from the matrix. To test its applicability, the method was used with samples consisting of soil, sediments, plants, water, carbon and air dust filter. The detection limit for the chemical yield attained of approx. 70% was 0.27 mBq per sample for Th-232, Th-230, Th-228, U-238, U-234 and Po-210. The detection limit for Pb-210 was 10 mBq per sample. On account of the influence by Ra-226 in the Ra-228 measurement and vice versa the detection limit is a function of the Ra-226 and Ra-228 concentrations, respectively, in the sample. The detection limits for the pure nuclides are 0.9 mBq per sample and 10 mBq per sample, respectively, for Ra-226 and Ra-228. (orig./HP)

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

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.K.; Dalai, Tarun K.; Krishnaswami, S. E-mail: swami@prl.ernet.in

    2003-07-01

    {sup 238}U and {sup 232}Th concentrations and the extent of {sup 238}U-{sup 234}U-{sup 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 {sup 238}U-{sup 234}U-{sup 230}Th radioactive equilibrium in them. {sup 238}U concentrations in Precambrian carbonates range from 0.06 to 2.07 {mu}g g{sup -1}. The 'mean' U/Ca in these carbonates is 2.9 ng U mg{sup -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 ({approx}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 {mu}g g{sup -1}. Based on this concentration, supply of U from at least {approx}50 mg of black shales per liter of river water is needed to balance the

  7. Specific Activities and Radioactive Contour Maps of Natural (238U, 232Th, 226Ra and 40K ) and Anthropogenic (137Cs) Radionuclides in Beach Sand Samples Collected from Nai Yang Beach of Phuket Province After Tsunai Disaster

    International Nuclear Information System (INIS)

    Full text: Specific activities of natural (238U, 232Th, 226Ra and 40K) and artificial anthropogenic (137Cs) radionuclides in 50 beach sand samples collected from Nai Yang beach in Phuket province which was effected from 2004 tsunami disaster, have been studied and measured. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system and also evaluated by using the standard reference materials IAEA/RGU-1, IAEA/RGTh-1, KCL and SL-2 which were obtained from Department of Physics, Faculty of Science, Prince of Songkhla University Hat Yai Campus. Experimental set-up and measurements were operated and carried out at Nuclear and Material Physics Laboratory in Department of Physics, Faculty of Science, Thaksin University Songkhla Campus. It was found that, the beach sand specific activity ranges from 862.50 to 3,356.35 Bq/kg for 40K, 3.51- 28.58 Bq/kg for 226Ra, 10.15 to 30.22 Bq/kg for 232Th and 0.00 to 2.39 Bq/kg for 137Cs with mean values of 1,843.03 ± 152.49 Bq/kg, 14.88 ± 3.30 Bq/kg, 19.19 ± 2.80 Bq/kg and 0.14 ± 0.11 Bq/kg, respectively. Furthermore, the results were also used to evaluate the absorbed dose rates in air (D), the radium equivalent (Raeq), the external hazard index (Hex) and the annual effective dose rate (AED) in all beach area. Moreover, experimental results were also compared to the Office of Atoms for Peace (OAP) research data, Thailand and global radioactivity measurements and evaluation, the recommended values which were proposed by the Organization for Economic Cooperation and Development (OECD, 1979) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 1988, 1993, 2000). Specific activities of natural and artificial anthropogenic radionuclides in all of Nai Yang beach sand samples could be also used to create the radioactive contour maps

  8. Determination of (226)Ra, (232)Th, (40)K, (235)U and (238)U activity concentration and public dose assessment in soil samples from bauxite core deposits in Western Cameroon.

    Science.gov (United States)

    Mekongtso Nguelem, Eric Jilbert; Moyo Ndontchueng, Maurice; Motapon, Ousmanou

    2016-01-01

    Determination of activity concentrations in twenty five (25) soil samples collected from various points in bauxite ore deposit in Menoua Division in Western of Cameroon was done using gamma spectrometry based Broad Energy Germanium (BEGe6530) detector. The average terrestrial radionuclides of (40)K, (226)Ra, (232)Th, (235)U and (238)U were measured as 671 ± 272, 125 ± 58, 157 ± 67, 6 ± 3 and 99 ± 69 Bq kg(-1), respectively. The observed activity concentrations of radionuclides were compared with other published values in the world. The outdoor absorbed dose rate in air varied from 96.1 to 321.2 nGy h(-1) with an average of 188.2 ± 59.4 nGy h(-1). The external annual effective dose rate and external hazard index were estimated as 0.23 ± 0.07 mSv year(-1) for outdoor, 0.92 ± 0.29 mSv year(-1) for indoor and 1.13 for the external hazard index, respectively. These radiological safe parameters were relatively higher than the recommended safe limits of UNSCEAR. Consequently, using of soil as building material might lead to an increase the external exposure to natural radioactivity and future applications research need to be conducted to have a global view of radioactivity level in the area before any undergoing bauxite ore exploitation. PMID:27536536

  9. [Uptake of radionuclides from soil to plant and the discovery of 226Ra, 232Th hyperaccumulator].

    Science.gov (United States)

    Zhang, Zhi-Qiang; Chen, Di-Yun; Song, Gang; Yue, Yu-Mei

    2011-04-01

    11 sorts of plant samples and corresponding soil samples were collected in Conghua and Taishan, Pearl River Delta. The specific activity of 238U, 226Ra, 232Th and 40K of samples were investigated by using HPGe-gamma-ray spectra analysis. The results showed that the average specific activity of 238U, 226Ra, 232Th and 40K in soil samples were 151.8, 146.3, 226.6, 665.5 Bq/kg, which were higher than the average values of China and the world. The concentration of 238U in all sort of plants are very low and most of them are lower than detection limit, while the values of 226Ra, 232Th and 40K were high. The contents of 226Ra and 232Th in Dicranopteris dichotoma were the highest, whose average specific activity is 285.9, 986.2 Bq/kg respectively. The average bioconcentration factors (BFs)of 26Ra, 232Th of Dicranopteris dichotoma were 2.20, 4.23, respectively, the other 10 sort of plants have BFs of 2266Ra, 232Th were in the range of 10(-1)-10(-2). The bioconcentration factors and the translocation factors of 226Ra, 232Th of Dicranopteris dichotoma. were all bigger than 1, so Dicranopteris dichotoma can be defined as hyperaccumulator of 226Ra and 232Th. PMID:21717763

  10. 232Th, a rigid rotor

    International Nuclear Information System (INIS)

    We undertake the present work to treat 232Th with a soft rotor formula used recently by C. Bihari et. al for γ-band and modified by J.B. Gupta et. al. It describes energy in terms of moment of inertia and softness parameter

  11. 238U And 232Th Concentration In Rock Samples using Alpha Autoradiography and Gamma Spectroscopy Techniques

    International Nuclear Information System (INIS)

    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

  12. Resonance integral calculations for isolated rods containing oxides of 238U and 232Th

    International Nuclear Information System (INIS)

    Results of resonance integral calculations for UO2 and ThO2 isolated rods are discussed. The calculations were performed with ENDF/B-IV cross-section data and the multigroup transport code ANISN. The findings reported demonstrate by comparison with semiempirical relationships (based on experimentally derived results) the suitability of the method used for determining resonance integrals. The calculations were based on a cylindrical rod in an H2O moderator of large radius. Multigroup cross sections were obtained by a MINX-SPHINX-AMMPX sequence, and ANISN was used to account for the neutron flux and capture rates. A special approach was used to determine a neutron source distribution such that the flux in the moderator region was forced to behave in an asymptotic way; thus, the ideal resonance integral experiment could be calculated. The UO2 resonance integrals calculated were in exceptionally good agreement with experimental values based on isolated rods. The ThO2 results were approximately 6% lower than experimental values, and efforts to understand the discrepancy are discussed. 8 figures, 7 tables

  13. Структура резонансной области поглощения ядер 238U и 232Th и зависимости ее параметров от температуры

    OpenAIRE

    Шаманин, И.; Годовых, А.

    2006-01-01

    Анализируются структуры резонансных областей в зависимостях сечений поглощения нейтронов от их энергии для четно"четных ядер 238U и 232Th. Теоретически обоснованы преимущества использования 232Th в качестве сырьевого нуклида при изготовлении ядерного топлива перспективных реакторов. В результате анализа установлены причины возрастания значений отрицательного температурного эффекта реактивности и оптимального водно"топливного отношения в тепловых реакторах в случае использо" вания торий содерж...

  14. 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)

    People have always been exposed to ionizing radiation originating from natural radionuclides including 238U, 40K, 232Th 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 238U concentrations in soil of Bela Crkva territory. Based on these measurements, risks of developing cancers are calculated using Monte Carlo method.(author)

  15. 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.

  16. Total kinetic energy distribution of fission fragments in 6,7Li + 238U reactions

    International Nuclear Information System (INIS)

    The shape and width of fission-fragment (FF) mass and kinetic energy distribution provides a lot of information on the fission reaction mechanism and the structure of the compound nucleus (CN), the fragments as well as the interacting nuclei. The shape of the mass distribution of the fission fragments for the actinides induced by the proton or neutron is known to change with the incident energy. At low energies, it shows a double humped distribution which changes slowly to a single humped distribution as energy increases. However, for a reaction involving a weakly bound projectile (i.e., 6Li + 232Th), a sharp change in the shape of the mass distribution with energy was observed. The sharp increase in the peak to valley ratio (P:V) in the fission-fragment mass distribution in 6Li + 232Th reaction by Itkis et al. and in 6,7Li + 238U reactions by Santra et al. was concluded to be due to the reduced energy transfer to the composite system caused by incomplete fusion (ICF) of alpha or deuteron/triton followed by fissions. Total Kinetic Energy (TKE) distribution of fission fragments is another important observable on which the effect of projectile breakup is not explored yet. In this contribution, the study of breakup/transfer effect on average TKE distribution for 6,7Li + 238U reactions is presented

  17. On an investigation of the dynamics of ternary fission for the system 238U + 238U

    International Nuclear Information System (INIS)

    With the three center model we have studied the dynamics of ternary fission for the system 238U + 238U by solving the one-dimensional collective Schroedinger equation with the potential energy surface given by the liquid-drop model and the mass parameters given by the Werner-Wheeler method

  18. Spectral interference corrections for the measurement of {sup 238}U in materials rich in thorium by a high resolution {gamma}-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yuecel, H. [Turkish Atomic Energy Authority (TAEA), Besevler Yerleskesi, Tandogan, 06100 Ankara (Turkey)], E-mail: alfa.haluky@gmail.com; Solmaz, A.N.; Koese, E.; Bor, D. [Institute of Nuclear Sciences of Ankara University (AU-INS), Tandogan, 06100 Ankara (Turkey)

    2009-11-15

    In this study, the spectral interferences are investigated for the analytical peaks at 63.3 keV of {sup 234}Th and 1001.0 keV of {sup 234m}Pa, which are often used in the measurement of {sup 238}U activity by the {gamma}-ray spectrometry. The correction methods are suggested to estimate the net peak areas of the {gamma}-rays overlapping the analytical peaks, due to the contribution of {sup 232}Th that may not be negligible in materials rich in natural thorium. The activity results for the certified reference materials (CRMs) containing U and Th were measured with a well type Ge detector. The self-absorption and true coincidence-summing (TCS) effects were also taken into account in the measurements. It is found that ignoring the contributions of the interference {gamma}-rays of {sup 232}Th and {sup 235}U to the mixed peak at 63.3 keV of {sup 234}Th ({sup 238}U) leads to the remarkably large systematic influence of 0.8-122% in the measured {sup 238}U activity, but in case of ignoring the contribution of {sup 232}Th via the interference {gamma}-ray at 1000.7 keV of {sup 228}Ac to the mixed peak at 1001 keV of {sup 234m}Pa ({sup 238}U) results in relatively smaller systematic influence of 0.05-3%, depending on thorium contents in the samples. The present results showed that the necessary correction for the spectral interferences besides self-absorption and TCS effects is also very important to obtain more accurate {sup 238}U activity results. Additionally, if one ignores the contribution of {sup 232}Th to both {sup 238}U and {sup 40}K activities in materials, the maximum systematic influence on the effective radiation dose is estimated to be {approx}6% and {approx}1% via the analytical peaks at 63.3 and 1001 keV for measurement of the {sup 238}U activity, respectively.

  19. /sup 238/U issues resolved and unresolved

    Energy Technology Data Exchange (ETDEWEB)

    de Saussure, G.; Smith, A.B.

    1982-01-01

    The interaction of 1 eV to 20 MeV neutrons with /sup 238/U is discussed with emphasis on recently resolved and remaining issues relevant to both application need and physical understanding. The apparent inability of older /sup 238/U evaluations to predict the measured /sup 238/U capture rate in thermal critical lattices has stimulated several recent precise measurements of the /sup 238/U cross sections, reanalysis of older data, and improved evaluations. The recent evaluations predict satisfactorily the /sup 238/U capture rate in thermal critical lattices. In the region from 1.5 to 4 keV there are differences of the order of 15%, sometimes larger, between the values of the neutron widths of the main resonances reported by several experimenters or obtained by different evaluators. Above 4 keV there are only sparse results of resonance analysis and most evaluations adopt a statistical treatment of the resonance structure. Some factors affecting the determination of the average properties of the resonance parameters are discussed. Above the inelastic-scattering threshold, energy-averaged neutron total, scattering, capture and fission cross sections are reviewed in a unified manner integrating measurement, calculation and evaluation. (n;n') and (n;2n') energy-transfer mechanisms are addressed. Particular attention is given to neutron capture, stressing precisions consistent with applied need. Fission properties are discussed including: prompt and delayed fission-neutron spectra and nubar, and fission-product yields. Physical understanding is assayed, with attention to compound-nucleus and direct-reaction mechanisms, and applications impact is illustrated in the context of fast-breeder-reactor performance. 95 references.

  20. Preparation of 232Th Target by Molecule Plating

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>For the cross section measurement of the 232Th(α, 2n)234U reaction, thorium targets plated on the aluminium foil with 2 and 8 μm thickness are required. It was demanded that the mass thickness of the

  1. Benchmarking ~(232)Th Evaluations With KBR and Thor Experiments

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The n+232Th evaluations from CENDL-3.1, ENDF/B-Ⅶ.0, JENDL-3.3 and JENDL-4.0 were tested with KBR series and THOR benchmark from ICSBEP Handbook. THOR is Plutonium-Metal-Fast (PMF) criticality benchmark reflected with metal thorium.

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

    International Nuclear Information System (INIS)

    In the present talk aspects of the reaction mechanism related to the survival probability of the heaviest fragments in 238U + 238U 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 238U + 238U reaction and by a presentation of the results obtained so far. In a third section our recent first attempts with the 238U + 248Cm reaction are described and preliminary results are discussed. (orig.)

  3. Correction methodology for the spectral interfering {gamma}-rays overlapping to the analytical peaks used in the analysis of {sup 232}Th

    Energy Technology Data Exchange (ETDEWEB)

    Yuecel, H., E-mail: haluk.yucel@ankara.edu.t [Institute of Nuclear Sciences, Ankara University (Australia), Besevler Yerleskesi, Tandogan, 06100 Ankara (Turkey); Koese, E. [Institute of Nuclear Sciences, Ankara University (Australia), Besevler Yerleskesi, Tandogan, 06100 Ankara (Turkey); Esen, A.N. [Energy Institute, Istanbul Technical University (ITU), Maslak, 34469 Istanbul (Turkey); Bor, D. [Institute of Nuclear Sciences, Ankara University (Australia), Besevler Yerleskesi, Tandogan, 06100 Ankara (Turkey)

    2011-06-15

    In the {gamma}-ray spectrometric analysis of the radionuclides, a correction factor is generally required for the spectral interfering {gamma}-rays in determining the net areas of the analytical peaks because some interfering {gamma}-rays often might contribute to the analytical peaks of interest. In present study, a correction methodology for the spectral interfering {gamma}-rays (CSI) is described. In particular, in the analysis of {sup 232}Th contained in samples, the interfering {gamma}-rays due to {sup 226}Ra, {sup 235}U, {sup 238}U and their decay products often overlap to the peaks of interest from {sup 232}Th decay products, and vise versa. For the validation of the proposed CSI method, several certified reference materials (CRM) containing U and Th were measured by using a 76.5% efficient n-type Ge detector. The required correction factors were quantified for spectral interference, self-absorption and true coincidence summing (TCS) effects for the relevant {gamma}-rays. The measured results indicate that if one ignores the contributions of the interfering {gamma}-rays to the analytical peaks at 583.2 keV of {sup 208}Tl and 727.3 keV of {sup 212}Bi, this leads to a significantly systematic influence on the resulted activities of {sup 232}Th. The correction factors required for spectral interference and TCS effects are estimated to be {approx}13.6% and {approx}15.4% for 583.2 keV peak. For the 727.3 keV peak, the correction factor is estimated to be {approx}15% for spectral interference, and {approx}5% for the TCS effects at the presently used detection geometry. On the other hand, the measured results also indicate that ignoring the contribution of the interfering {gamma}-rays to the areas of the analytical peaks at 860.6 keV of {sup 208}Tl, 338.3 and 911.2 keV of {sup 228}Ac does not lead to any significant systematic influence on the {sup 232}Th analysis. Because these factors are remained generally less than {approx}5%, i.e., within overall uncertainty

  4. Dynamical Effects of Orientations on reaction 238U+238U near Coulomb Barrier

    International Nuclear Information System (INIS)

    The dynamical effects of three orientations (nose-nose, nose-side, and side-side) on reaction 238U+238U have been investigated by using Improved Quantum Molecular Dynamics(ImQMD) model. Due to Coulomb repulsive interaction, the change of the deformations or orientations of colliding nuclei is found even before touching configuration, especially for nose-nose. The average lifetime of the giant system and the probability producing super-heavy fragments (SHF) with Z>110 are found to be dependent on the orientations of two nuclei. At the time of 1000fm/c after re-separation of giant system, side-side orientation provide a larger probability of producing SHF than nose-nose case. And the maximum value of the probability locates a smaller incident energy for side-side orientation compared with nose-nose.

  5. Study on the formation of the composite system of 238U+238U

    Institute of Scientific and Technical Information of China (English)

    WU Xi-Zhen; TIAN Jun-Long; ZHAO Kai; ZHANG Ying-Xun; LI Zhu-Xia

    2009-01-01

    Strongly damped reactions of 238U+238U, at Ecm = 680-1880 MeV have been studied based on the improved quantum molecular dynamics model. We find that at a certain energy region the entrance channel potential is weakly repulsive and the dissipation is very strong after touching configuration, these two effects make the time delay of re-separation for colliding system. The single particle potential well of the transiently formed composite system has Coulomb barrier about 15-20 MeV high at the surface, which makes the excited unbound protons being still embedded in the potential well and moving in a common mono-single particle potential for a period of time and thus restrains from quick decay of the composite system.

  6. Precise measurement and analysis of neutron transmission through 232Th

    International Nuclear Information System (INIS)

    Three sets of transmission time spectra through up to eight samples of 232Th have been measured for neutron energies from 6.0 MeV to 0.1 MeV by use of a flight-time technique over 22- and 40-m path lengths, the ORELA pulsed neutron source, and a 1-mm-thick lithium glass detector. The resulting total cross section from 0.1 to 20.0 eV seems to be smaller than that contained in the ENDF/B-V evaluation. Least-squares analysis of the transmissions from 9 to 440 eV using a multilevel Breit-Wigner formalism results in neutron widths consistent with those previously reported. An average radiation width of 25.2 MeV is obtained for 19 low-energy s-wave resonances. 3 figures, 5 tables

  7. Activity ratios of (234)U/(238)U and (226)Ra/(228)Ra for transport mechanisms of elevated uranium in alluvial aquifers of groundwater in south-western (SW) Punjab, India.

    Science.gov (United States)

    Kumar, A; Karpe, R K; Rout, S; Gautam, Y P; Mishra, M K; Ravi, P M; Tripathi, R M

    2016-01-01

    The concentrations of total dissolved uranium (U), its isotopic composition ((234)U, (235)U, (238)U) and two long lived Ra isotopes ((226)Ra and (228)Ra) in alluvial aquifers of groundwater were determined to investigate the groundwater flow pattern in the south-western (SW) Punjab, India. Particular attention was given to the spatial variability of activity ratios (ARs) of (234)U/(238)U and (226)Ra/(228)Ra to predict the possible sources and supply process of U into the water from the solid phase. The measured groundwater (234)U/(238)U ARs were ∼1 or >1 in the shallow zone (depth  30 m) with relatively low U concentration. The simultaneous elevated U concentration and (234)U/(238)U ARs in waters were possibly due to differences in imprints of rock-water interactions under hydrologic conditions. However, (234)U/(238)U ARs geochemistry of the two isotopes. On the other hand, (226)Ra/(228)Ra ARs in groundwaters varied widely and observed about 50-300 times higher than (238)U/(232)Th ARs in granitic rocks or soils. Such elevation in ARs might be attributed to different dissolution properties of their parents during water-rock interactions or lattice damage during decay or local enrichments of uranium in the aquifers. PMID:26555366

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

    Science.gov (United States)

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

    2016-10-01

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

  9. Simultaneous evaluation for (n,f) cross section of 235U, 239Pu, 238U and (n,γ) cross sections of 238U

    International Nuclear Information System (INIS)

    The fission cross sections for 235U, 238U, 239Pu, the capture cross sections for 238U and the ratios for 239Pu(n,f)/235U(n,f), 238U(m,f)/235U(n,f), 238U(n,γ)/235U(n,f) were firstly evaluated respectively. The experimental data were collected, analysed, selected and corrected. The data were fitted with spline fit program

  10. 放射性核素土壤-植物吸收与钍、镭富集植物的发现%Uptake of Radionuclides from Soil to Plant and the Discovery of 226Ra, 232Th Hyperaccumulator

    Institute of Scientific and Technical Information of China (English)

    张志强; 陈迪云; 宋刚; 岳玉美

    2011-01-01

    11 sorts of plant samples and corresponding soil samples were collected in Conghua and Taishan, Pearl River Delta. The specific activity of 238U、226Ra、232Th and 40K of samples were investigated by using HPGe-γ-ray spectra analysis. The results showed that the average specific activity of 238U, 226Ra, 232Th and 40K in soil samples were 151.8, 146. 3, 226. 6, 665.5 Bq/kg, which were higher than the average values of China and the world. The concentration of 238U in all sort of plants are very low and most of them are lower than detection limit, while the values of 226Ra, 232Th and 4OK were high. The contents of 226Ra and 232Th in Dicranopteris dichotoma were the highest, whose average specific activity is 285.9, 986. 2 Bq/kg respectively. The average bioconcentration factors (BFs)of 226Ra,232Th of Dicranopteris dichotoma were 2. 20, 4.23, respectively, the other 10 sort of plants have BFs of 226Ra, 232Th were in the range of 10 -1 -10-2. The bioconcentration factors and the translocation factors of 226Ra, 232Th of Dicranopteris dichotoma were all bigger than 1, so Dicranopteris dichotoma can be defined as hyperaccumulator of 226Ra and 232Th.%对采集珠江三角洲从化、台山等地的11种植物以及对应的土壤样品,采用HPGe-y能谱分析了其中的天然放射性核素U、Ra、Th和K的比活度,结果表明,土壤样品中U、Ra、Th和K的平均含量为151.8、146.3、226.6和665.5Bq/kg,高于我国和世界的平均值,植物样品中的U含量较低,大多数样品低于检出限,而Ra、Th和K的平均含量相对较高.铁芒萁(Dicranopteris dichotoma)样品中Ra、Th含量最高,平均值分别为285.9 Bq/kg、968.5 Bq/kg,对应的生物富集系数(bioconcentration factor)的平均值为2.20、4.23,而其它10种植物Ra、Th的生物富集系数均在10~10的范围.铁芒萁Ra和Th的富集系数和转移系数(translocation factor)都大于1,可以认为是Ra和Th的超富集植物.

  11. Study of the violent collisions between 63Cu+232Th at 35 MeV/nucleon

    Science.gov (United States)

    Cibor, J.; Majka, Z.; Kozik, T.; Staszel, P.; Sosin, Z.; Hagel, K.; Li, J.; Lou, L.; Tezkratt, R.; Utley, D.; Wada, R.; Xiao, B.; Natowitz, J. B.

    1997-01-01

    A study of the decay of hot and heavy composite nuclei produced in the violent collisions between 63Cu and 232Th at 35A MeV is presented. The measurement of fission fragment correlations indicates that ~ 70% of the projectile linear momentum can be transferred to the fissioning system. Heavy reaction products were observed at a laboratory angle of θ=6° in coincidence with neutrons, light charged particles, and intermediate mass fragments. The dynamical aspects of the collisions between the projectile and target nuclei were investigated using the computer code CHIMERA which is based upon the molecular dynamics concept. Asymptotic characteristics of the reaction products were confronted with results of calculations of the tandem CHIMERA plus GEMINI codes. The data and model comparisons show that a composite system of mass as high as 275 amu and with an excitation energy ~ 1 GeV is formed in the most violent collisions. Some of the heavy reaction remnants are located on the fragment mass versus velocity plane inside the area where the evaporation residues resulting from the decay of the hot composite system are expected. A high neutron multiplicity associated with these events indicates their origin in the most dissipative events. However, a low cross section for the production of these remnants and the close similarity of their characteristics to the fission fragments do not allow more conclusive statements.

  12. Calculation of fusion time scales in 11B + 237Np, 12C + 232Th and 16O + 232Th reactions in a dynamical trajectory model

    International Nuclear Information System (INIS)

    There are several theoretical models which treat the fusion process and energy dissipation in heavy ion collision in terms of a fluctuating force represented by the coupling between macroscopic and intrinsic degrees of freedom. One such dynamical model has been developed by Feldmeier (1987), where the properties of the dissipative force are determined from a microscopic picture of particle exchange between two nuclei. The macroscopic shapes of the nuclear system are represented by axially symmetric configuration with sharp surfaces. We have used the above model to calculate the fusion time scales for the systems 11B + 237Np, 12C +232Th and 16O + 232Th at 77, 86 and 104 MeV bombarding energies to examine the effect of mass asymmetry in fusion dynamics. (author). 2 figs

  13. Electric and Magnetic Dipole States in ^238U

    Science.gov (United States)

    Hammond, S. L.; Adekola, A.; Angell, C. T.; Karwowski, H. J.; Howell, C. R.; Kwan, E.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Kelley, J. H.

    2010-11-01

    An investigation of dipole states in ^238U is important for the fundamental understanding of its structure. Precise experimental information on the distribution of M1 and E1 transitions in ^238U has been obtained using the nuclear resonance fluorescence technique at the High-Intensity γ-ray Source at the Triangle Universities Nuclear Laboratory. Using 100% linearly-polarized, monoenergetic γ-ray beams between incident energies of 2.0 - 5.5 MeV, the spin, parity, width, and γ-strength of the ground-state deexcitations were determined. These measurements will form a unique data set that can be used for comparison with theoretical models of collective excitations in heavy, deformed nuclei. The data can also provide isotope-specific signatures to search for special nuclear materials.

  14. Delayed fission of the 238U muonic atom

    International Nuclear Information System (INIS)

    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 238U atom and conversion of muons from the fission fragments

  15. Investigation of the (232)Th Nucleus Excitations at the FEL {gamma} - Nucleus Colliders

    CERN Document Server

    Koru, H; Sultansoy, S F; Sarer, B

    2001-01-01

    The physics search potential of the FEL {gamma} - Nucleus colliders is analysed using excitations of the (232)Th nucleus. It is shown that, due to the monochromacity of FEL {gamma} beam and high statistics, proposed colliders will play an important role in the field of "traditional" nuclear physics.

  16. Feeding of the {sup 232}Th levels from the decay of {sup 236}U

    Energy Technology Data Exchange (ETDEWEB)

    Gehrke, R.J. E-mail: rjg@inel.gov; Baker, J.D.; Riddle, C.L

    2002-03-01

    Population of the 6{sup +} 332 keV level in {sup 232}Th from the decay of {sup 236}U was observed for the first time. The 49, 112, and 171 keV {gamma}-ray energies and relative intensities from the decay of {sup 236}U were measured.

  17. 230,232Th in milk, meat, and grain in Korea

    International Nuclear Information System (INIS)

    The concentrations of natural radioisotopes 230Th and 232Th in Korean foods were measured by the method of calcium oxalate co-precipitation in addition to the conventional anion-exchange method and alpha spectroscopic measurement. The 230Th concentrations (mBq/kg-fresh) in Korean foods were found to be as follows: milk 0.14-2.45, pork 2.98-8.97, beef 1.94-9.80, chicken 1.22-13.0, rice 0.43-2.35, wheat 0.53-14.4, and soybeans, 8.44-91.6. The 232Th concentrations (mBq/kg-fresh) in Korean foods were found to be as follows: milk 0.01-2.46, pork 0.28-9.32, beef 1.02-5.34, chicken 0.56-4.98, rice 0.32-2.54, wheat 0.53-20.0, and soybeans, 2.30-42.2. The annual internal dose of Th was also estimated. The annual internal dose of 230Th and 232Th in milk was about 0.006 μSv/yr and much lower than that of other countries because of the low intake of milk in Korea compared to other countries. The annual internal dose of 230Th and 232Th in the rice was about 0.043 μSv/yr and highest because rice is the staple food of Koreans. (author)

  18. Distribution of 226Ra, 232Th, and 40K in rice plant components and physico-chemical effects of soil on their transportation to grains

    Directory of Open Access Journals (Sweden)

    Mohammed Saad Alsaffar

    2015-07-01

    Full Text Available Radioactivity distribution and transfer factor (TF in plants are crucial parameters used to assess radioactive contamination in the environment and its risks to humans. In this study, the activities of 226Ra, 232Th, and 40K were successfully measured via gamma-ray spectrometry on rice plant components (root, straw, husk, and grain and on corresponding soil samples collected from paddy fields in Penang, Malaysia. Soil physico-chemical characteristics (pH, cation exchange capacity, electrical conductivity, organic matter, and soil texture were also analyzed for their estimated effects on soil–grain TF. A major fraction of the total 226Ra and 232Th activities measured as 47% and 57%, respectively, were concentrated in the roots, whereas only about 9% and 8% were distributed in the grains, correspondingly. 40K activity accumulation was about 59% in the straw and 7% in the grains. Rice soil–grain TFs were observed in the ranges of (0.06–0.36 × 10−1 for 226Ra, (0.04–0.14 × 10−1 for 232Th, and (0.74–4.72 × 10−1 for 40K. Results showed that the selected radionuclide distributions in rice are dependent on component type, and their grain concentrations are not linearly related to their soil concentrations. These findings indicated that uptake predominantly depends on soil physico-chemical characteristics.

  19. Multifragmentation for 36Ar+238U treated as statistical dynamic interaction processes

    International Nuclear Information System (INIS)

    The exclusive multifragment multiplicities for the system 36Ar+238U at 35 MeV/nucleon incident energy are calculated using the Boltzmann master equation for the fast cascade, and the Weisskopf-Ewing evaporation model for successive binary decay of the equilibrated residues. These calculated results are consistent with the experimental results of Kim et al. We show that the multiplicity distribution in such a model has a sensitivity to the equilibrated excitation, so that multiplicity could be an observable characteristic of excitation. This in turn may be used to infer time delay for fragment emission (in a model dependent way)

  20. 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

  1. Neutron Induced Capture and Fission Processes on 238U

    OpenAIRE

    Oprea Cristiana; Oprea Alexandru

    2016-01-01

    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...

  2. Charge-pickup of 238U at relativistic energies

    International Nuclear Information System (INIS)

    Cross sections for the charge-pickup of 238U 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.)

  3. 238U sbnd 230Th sbnd 226Ra disequilibria in young Mount St. Helens rocks: time constraint for magma formation and crystallization

    Science.gov (United States)

    Volpe, Alan M.; Hammond, Paul E.

    1991-12-01

    We use 238U-series nuclides and 230Th/ 232Th ratios measured by mass spectrometry to constrain processes and time scales of calc-alkaline magma genesis at Mount St. Helens, Washington. Olivine basalt, pyroxene andesites and dacites that erupted 10-2 ka ago show 3-14% ( 230Th) sbnd ( 238U) and 6-54% 226Ra sbnd 230Th disequilibria. Mineral phases exhibit robust ( 226Ra) sbnd ( 230Th) fractionation. Plagioclase has large 65-280% ( 226Ra) excesses, and magnetite has large 65% ( 226Ra) deficits relative to ( 230Th). Calculated partition coefficients for Ba, Th, and U in mineral-groundmass pairs, except Ba in plagioclase, are low (⩽ 0.04). Correlation between ( 226Ra/ 230Th ) activity ratios and rm/BaTh element ratios in the minerals suggests that 226Ra partitions similar to Ba during crystallization. Internal ( 230Th) sbnd ( 238U) isochrons for 1982 summit and East Dome dacites and Goat Rocks and Kalama andesites show that closed Th sbnd U system fractionation occurred 2-6 ka ago. Apparent internal isochrons for Castle Creek basalt (34 ka) and andesite (27 ka) suggest longer magma chamber residence times and mixing of old crystals and young melt. Mineral ( 226Ra) sbnd ( 230Th) disequilibrium on Ba-normalized internal isochron diagrams suggests average magma chamber residence times of 500-3000 years. In addition, radioactive ( 226Ra/ 230Th ) heterogeneity between minerals and groundmass or whole rock is evidence for open-system Ra sbnd Th behavior. This heterogeneity suggests there has been recent, post-crystallization, changes in melt chemical composition that affected 226Ra more than 230Th. Clearly, magma fractionation, residence and transport of crystal-melt before eruption of chemically diverse lavas at Mount St. Helens occurs over geologically short periods.

  4. Measurement of 232Th(, ) and 232Th(, 2) cross-sections at neutron energies of 13.5, 15.5 and 17.28 MeV using neutron activation techniques

    Indian Academy of Sciences (India)

    Sadhana Mukerji; H Naik; S V Suryanarayana; S Chachara; B S Shivashankar; V Mulik; Rita Crasta; Sudipta Samanta; B K Nayak; A Saxena; S C Sharma; P V Bhagwat; K K Rasheed; R N Jindal; S Ganesan; A K Mohanty; A Goswami; P D Krishnani

    2012-08-01

    The 232Th(, ) reaction cross-section at average neutron energies of 13.5, 15.5 and 17.28 MeV from the 7Li(, ) reaction has been determined for the first time using activation and off-line -ray spectrometric technique. The 232Th(, 2) cross-section at 17.28 MeV neutron energy has also been determined using the same technique. The experimentally determined 232Th(, ) and 232Th(, 2) reaction cross-sections from the present work were compared with the evaluated data of ENDF/BVII and JENDL-4.0 and were found to be in good agreement. The present data, along with literature data in a wide range of neutron energies, were interpreted in terms of competition between 232Th(, ), (, ), (, ) and (, ) reaction channels. The 232Th(, ) and 232Th(, 2) reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were found to be in good agreement with the experimental data from the present work but were slightly higher than the literature data at lower neutron energies.

  5. Measurement of the generation ratio of 233U and the average radiation capture cross section of 232Th with 232ThO2 irradiated by fast neutrons

    International Nuclear Information System (INIS)

    Background: Thorium-Uranium cycle plays an important role in the future's power production technology. Nuclear data involved are urgently needed for engineering design and other purposes since there are obvious differences between the existing evaluated data. Macroscopic neutron integral experiment can be used as a good tool to survey the confusion. Purpose: Macroscopic neutron integral experiment based on radioactive method was carried out to measure the generation ratio of 233U nuclide and the average radiation capture cross section of 232Th while a ThO2 sample was irradiated by fast neutrons leakage from a fast critical facility. We expect that these data can be used as a reference for the research of Th-U cycle. Methods: Radiation capture reactions of 232Th nuclides occur when the nuclides are irradiated by neutrons. 233U nuclides will be generated after two cascade decays by emitting beta rays from the activation products, which are 233Th nuclides. The ThO2 sample was prepared as a slice of 20 mm×10 mm from 0.743 36-g ThO2 powders of 99.9% enriched. The neutron flux was measured by activation method which was 4.07x109 cm-2·s-1 at the sample's irradiation position while the facility worked at the power level of 180 watts. The leakage neutrons' energy distribution was calculated by MC method and it is very close to the fission spectrum with the averaged energy of 1.42 MeV. After irradiation and then a period of cooling time the gamma rays emitted from the sample were measured by an HPGe spectrometer which had been pre-calibrated. From these data the activity of 233Pa was calculated and then the generation ratio of 233U and the average radiation capture cross section of 232Th were calculated. The measured average radiation capture cross section was compared with the cross sections calculated based on the ENDFB-VH.1, CENDL-3.1, JENDL-4.0, BROND2.2 databases. Results: The measured generation ratio of 233U was 4.01×10-12 with an uncertainty of 6

  6. The production of unknown neutron-rich isotopes in $^{238}$U+$^{238}$U collisions at near-barrier energy

    CERN Document Server

    Zhao, Kai; Zhang, Yingxun; Wang, Ning; Li, Qingfeng; Shen, Caiwan; Wang, Yongjia; Wu, Xizhen

    2016-01-01

    The production cross sections for primary and residual fragments with charge number from $Z$=70 to 120 produced in the collision of $^{238}$U+$^{238}$U at 7.0 MeV/nucleon are calculated by the improved quantum molecular dynamics (ImQMD) model incorporated with the statistical evaporation model (HIVAP code). The calculation results predict that about sixty unknown neutron-rich isotopes from element Ra ($Z$=88) to Db ($Z$=105) can be produced with the production cross sections above the lower bound of $10^{-8}$ mb in this reaction. And almost all of unknown neutron-rich isotopes are emitted at the laboratory angles $\\theta_{lab}\\leq$ 60$^\\circ$. Two cases, i.e. the production of the unknown uranium isotopes with $A\\geq$ 244 and that of rutherfordium with $A\\geq$ 269 are investigated for understanding the production mechanism of unknown neutron-rich isotopes. It is found that for the former case the collision time between two uranium nuclei is shorter and the primary fragments producing the residues have smaller...

  7. 226Ra, 232Th and 40K analysis in water samples from Assiut, Egypt

    International Nuclear Information System (INIS)

    The activity concentrations of 226Ra, 232Th and 40K were determined in water samples, using 2”x 2” NaI(Tl) scintillation detector. Water activity ranges from 0.07 to 0.59 Bq L−1 for 226Ra, 0.05 to 0.37 Bq L−1 for 232Th and 3.25 to 8.72 Bq L−1 for 40K with mean values of 2.64, 2.22 and 119.50 Bq L−1, respectively. As far as the measured gamma radionuclides is concerned, the mean annual effective doses for all analyzed samples of water are in the range of 0.02–0.08, 0.03-0.17 and 0.03-0.10 mSv yr-1 for infants, children and adults, respectively, all being lower than the reference level of the committed effective dose recommended by the WHO.

  8. Fractional absorption in gastrointestinal tract of 232Th by ingestion for Chinese man

    International Nuclear Information System (INIS)

    Objective: To estimate fractional absorption in gastrointestinal tract (f1) of 232Th by ingestion for the Chinese male adults. Methods: According to f1 calculation method in literature and results of Th concentrations in dietary foods and organ or tissues for the Chinese male adults, obtained in recent years, f1 values were estimated from the median and mean Th concentrations and compared each other. Results: the f1 value from the median and mean Th concentrations was 0.00048 and 0.00028 respectively. Conclusion: The f1 of 232Th by ingestion for the Chinese male adults should be adopted as 0.00048, being lower than estimated result from the world reference concentrations in UNSCEAR 2000 Report, but quite near to the relevant reported value from Asian countries, such as India or Japan, and supporting the latest recommended value 0.0005 by ICRP too

  9. Fission Product Decay Heat Calculations for Neutron Fission of 232Th

    Science.gov (United States)

    Son, P. N.; Hai, N. X.

    2016-06-01

    Precise information on the decay heat from fission products following times after a fission reaction is necessary for safety designs and operations of nuclear-power reactors, fuel storage, transport flasks, and for spent fuel management and processing. In this study, the timing distributions of fission products' concentrations and their integrated decay heat as function of time following a fast neutron fission reaction of 232Th were exactly calculated by the numerical method with using the DHP code.

  10. Photofission product yields of 238U and 239Pu with 22-MeV bremsstrahlung

    Science.gov (United States)

    Wen, Xianfei; Yang, Haori

    2016-06-01

    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 238U 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 238U and 239Pu 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.

  11. 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.

  12. Neutron Induced Capture and Fission Processes on 238U

    Science.gov (United States)

    Oprea, Cristiana; Oprea, Alexandru

    2016-03-01

    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.

  13. Resonant upscattering effects on 238U absorption rates

    International Nuclear Information System (INIS)

    The new requirements of accuracy in reactor physics calculations justify a review of the current models, like that one adopted in the cross-section processing, for a better evaluation of the keff and the resonant absorption rates. In this context, the aim of this paper is to investigate the effects of the free gas kernel developed by Sanchez on the 238U absorption rates. Homogeneous medium tests point out the increase of the absorption rates in the left wing of the resonances due to the upscattering produced by the new kernel. Heterogeneous tests show that the absorption in the left wing of the resonances is mostly affected by the scattering anisotropy in the laboratory system. (author)

  14. Elastic and inelastic scattering of neutrons on 238U nucleus

    Directory of Open Access Journals (Sweden)

    Capote R.

    2014-04-01

    Full Text Available Advanced modelling of neutron induced reactions on the 238U nucleus is aimed at improving our knowledge of neutron scattering. Capture and fission channels are well constrained by available experimental data and neutron standard evaluation. A focus of this contribution is on elastic and inelastic scattering cross sections. The employed nuclear reaction model includes – a new rotational-vibrational dispersive optical model potential coupling the low-lying collective bands of vibrational character observed in even-even actinides; – the Engelbrecht-Weidenmüller transformation allowing for inclusion of compound-direct interference effects; – and a multi-humped fission barrier with absorption in the secondary well described within the optical model for fission. Impact of the advanced modelling on elastic and inelastic scattering cross sections including angular distributions and emission spectra is assessed both by comparison with selected microscopic experimental data and integral criticality benchmarks including measured reaction rates (e.g. JEMIMA, FLAPTOP and BIG TEN. Benchmark calculations provided feedback to improve the reaction modelling. Improvement of existing libraries will be discussed.

  15. Monitoring of 232Th in soil of the state of Pernambuco, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Santos Junior, Jose Araujo dos; Silva, Cleomacio Miguel da; Silveira, Sueldo Vita; Amaral, Romilton dos Santos [Pernambuco Univ., Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia (GERAR)]. E-mail: jaraujo@ufpe.br; Cardoso, Jorge Joao Ricardo Ferreira [Pernambuco Univ., Recife, PE (Brazil). Dept. de Geologia]. E-mail: jcardoso@ufpe.br

    2005-07-01

    where the control of radionuclides in the environment is of extreme importance for attaining information on potential sources of radioactive contamination. The gamma spectrometry with high resolution detector is a rapid and efficient method in the determination of natural radionuclides in environment samples. Using the gamma spectrometry with HPGe, it was possible to measure the radiological concentrations of {sup 232}Th in seventy eight soil samples, collected in an area of approximately 40,000 m{sup 2}, around a natural radioactive occurrence, located in the rural region of the state Pernambuco, Brazil. The samples of 200 g, were reduced to a granulometry less than 63 {mu}m, homogenized, conditioned in hermetically sealed polyethylene containers for thirty days, and measured in the laboratory for 43,200 seconds, each. The measurements of the activities of {sup 232}Th were based on the gamma emissions of the photo peaks at 338 keV and 911 keV of {sup 228}Ac in secular radioactive balance, and allowed the evaluation of the distribution of these radionuclides in the environment. For the calculation of the specific activities of {sup 232}Th, the average of the rates of counting in the energies of 338 keV and 911 keV was used (discrepancy of approximately 5 %). The values of the measured activities have variations of 77 to 423 Bq.kg{sup -1} (arithmetic mean 227 Bq.kg{sup -1}; median 217 Bq.kg{sup -1}). The average factor concentration was approximately 6. (author)

  16. Studying Nuclear Level Densities of 238U in the Nuclear Reactions within the Macroscopic Nuclear Models

    Science.gov (United States)

    Razavi, Rohallah; Rahmatinejad, Azam; Kakavand, Tayeb; Taheri, Fariba; Aghajani, Maghsood; Khooy, Asghar

    2016-02-01

    In this work the nuclear level density parameters of 238U have been extracted in the back-shifted Fermi gas model (BSFGM), as well as the constant temperature model (CTM), through fitting with the recent experimental data on nuclear level densities measured by the Oslo group. The excitation functions for 238U(p,2nα)233Pa, and 238U(p,4n)235Np reactions and the fragment yields for the fragments of the 238U(p,f) reaction have been calculated using obtained level density parameters. The results are compared to their corresponding experimental values. It was found that the extracted excitation functions and the fragment yields in the CTM coincide well with the experimental values in the low-energy region. This finding is according to the claim made by the Oslo group that the extracted level densities of 238U show a constant temperature behaviour.

  17. The applicability of MGA method for depleted and natural uranium isotopic analysis in the presence of actinides (232Th, 237Np, 233Pa and 241Am).

    Science.gov (United States)

    Yücel, Haluk

    2007-11-01

    The multi-group analysis (MGA) method for the determination of uranium isotopic abundances in depleted uranium (DU) and natural uranium (NU) samples is applied in this study. A set of non-destructive gamma-ray measurements of DU and NU samples were performed using a planar Ge detector. The relative abundances of 235U and 238U isotopes were compared with the declared values of the standards. The relative abundance for 235U obtained by MGA for a "clean" DU or NU sample with a content of uranium>1wt% is determined with an accuracy of about +/-5%. However, when several actinides such as 232Th, 237Np, 233Pa and 241Am are present along with uranium isotopes simulating "dirty" DU or NU, it has been observed that MGA method gives erroneous results. The 235U abundance results for the samples were 6-25 times higher than the declared values in the presence of above-mentioned actinides, since MGA is utilized the X-ray and gamma-ray peaks in the 80-130 keV energy region, covering XKalpha and XKbeta regions. After the least-squares fitting of the spectra, it is found that the increases in the intensities of the X-ray and gamma-ray peaks of uranium are remarkably larger in the complex 80-130 keV region. On the other hand, it is observed that the interferences of the actinide peaks are relatively less dominant in the higher gamma-ray region of 130-300 keV. The results imply the need for dirty DU and NU samples that the MGA method should utilize the higher energy gamma-rays (up to 1001 keV of (234m)Pa) combined with lower energies of the spectra, which may be collected in a two detector mode (a planar Ge and a high efficient coaxial Ge). PMID:17606378

  18. Neutron capture cross section measurements for 238U in the resonance region at GELINA

    Science.gov (United States)

    Kim, H. I.; Paradela, C.; Sirakov, I.; Becker, B.; Capote, R.; Gunsing, F.; Kim, G. N.; Kopecky, S.; Lampoudis, C.; Lee, Y.-O.; Massarczyk, R.; Moens, A.; Moxon, M.; Pronyaev, V. G.; Schillebeeckx, P.; Wynants, R.

    2016-06-01

    Measurements were performed at the time-of-flight facility GELINA to determine the 238U(n, γ) cross section in the resonance region. Experiments were carried out at a 12.5 and 60m measurement station. The total energy detection principle in combination with the pulse height weighting technique was applied using C6D6 liquid scintillators as prompt γ-ray detectors. The energy dependence of the neutron flux was measured with ionisation chambers based on the 10B(n, α) reaction. The data were normalised to the isolated and saturated 238U resonance at 6.67 eV. Special procedures were applied to reduce bias effects due to the weighting function, normalization, dead time and background corrections, and corrections related to the sample properties. The total uncertainty due to the weighting function, normalization, neutron flux and sample characteristics is about 1.5%. Resonance parameters were derived from a simultaneous resonance shape analysis of the GELINA capture data and transmission data obtained previously at a 42m and 150m station of ORELA. The parameters of resonances below 500 eV are in good agreement with those resulting from an evaluation that was adopted in the main data libraries. Between 500 eV and 1200 eV a systematic difference in the neutron width is observed. Average capture cross section data were derived from the experimental capture yield in the energy region between 3.5 keV and 90 keV. The results are in good agreement with an evaluated cross section resulting from a least squares fit to experimental data available in the literature prior to this work. The average cross section data derived in this work were parameterised in terms of average resonance parameters and included in a least squares analysis together with other experimental data reported in the literature.

  19. Studies of positron electron pair production in {sup 238}U + {sup 181}Ta

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Back, B.B.; Betts, R.R. [and others

    1995-08-01

    Following the completion of APEX in late 1993, a two-week run on the {sup 238}U + {sup 181}Ta system at 6.1 and 6.3 MeV/u with 1 mg/cm{sup 2} targets provided, for the first time, data in which the expected sharp sum-energy lines should appear. Data from previous experiments show evidence for sharp sum-energy lines at 625, 748 and 805 keV, observed at bombarding energies from 5.9 to 6.3 MeV/u. The 625- and 809-keV lines display the characteristics of equal-energy back-to-back emission whereas the 748-keV line shows a rather different behavior. In our measurements, average beam currents of 2-3 pnA from the ATLAS accelerator were used to bombard 1-mg/cm{sup 2} rolled {sup 181}Ta targets, the energy loss in which corresponds to the ranges of bombarding energies over which the sharp sum-energy lines were previously reported. A run at 5.95 MeV/u for {sup 238}U + {sup 181}Ta followed in May 1994. These data were analyzed extensively. Sum-energy spectra measured in coincidence with scattered ions in the range 20{degrees} < {theta} < 68{degrees}. No evidence is found for the sharp sum-energy lines reported previously and, depending on the scenario assumed for the production mechanism and kinematics of the pairs, upper limits on cross sections at the 90% confidence limit range from 10-100 times smaller than the values that can be deduced from the earlier reports. We are in the process of refining the data analysis and simulations of the apparatus in order to finalize these numbers for publication.

  20. Spatial variability of initial 230Th/ 232Th in modern Porites from the inshore region of the Great Barrier Reef

    Science.gov (United States)

    Clark, Tara R.; Zhao, Jian-xin; Feng, Yue-xing; Done, Terry J.; Jupiter, Stacy; Lough, Janice; Pandolfi, John M.

    2012-02-01

    The main limiting factor in obtaining precise and accurate uranium-series (U-series) ages of corals that lived during the last few hundred years is the ability to constrain and correct for initial thorium-230 ( 230Th 0), which is proportionally much higher in younger samples. This is becoming particularly important in palaeoecological research where accurate chronologies, based on the 230Th chronometer, are required to pinpoint changes in coral community structure and the timing of mortality events in recent time (e.g. since European settlement of northern Australia in the 1850s). In this study, thermal ionisation mass spectrometry (TIMS) U-series dating of 43 samples of known ages collected from living Porites spp. from the far northern, central and southern inshore regions of the Great Barrier Reef (GBR) was performed to spatially constrain initial 230Th/ 232Th ( 230Th/ 232Th 0) variability. In these living Porites corals, the majority of 230Th/ 232Th 0 values fell within error of the conservative bulk Earth 230Th/ 232Th atomic value of 4.3 ± 4.3 × 10 -6 (2 σ) generally assumed for 230Th 0 corrections where the primary source is terrestrially derived. However, the results of this study demonstrate that the accuracy of 230Th ages can be further improved by using locally determined 230Th/ 232Th 0 values for correction, supporting the conclusion made by Shen et al. (2008) for the Western Pacific. Despite samples being taken from regions adjacent to contrasting levels of land modification, no significant differences were found in 230Th/ 232Th 0 between regions exposed to varying levels of sediment during river runoff events. Overall, 39 of the total 43 230Th/ 232Th 0 atomic values measured in samples from inshore reefs across the entire region show a normal distribution ranging from 3.5 ± 1.1 to 8.1 ± 1.1 × 10 -6, with a weighted mean of 5.76 ± 0.34 × 10 -6 (2 σ, MSWD = 8.1). Considering the scatter of the data, the weighted mean value with a more

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

    International Nuclear Information System (INIS)

    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

  2. Measurement and calculation of 238U fission reaction rates induced by neutrons reflected by carbon material

    International Nuclear Information System (INIS)

    To check the data of carbon material reflecting neutrons, the distribution of 238U fission reaction rates induced by D-T fusion neutrons reflected by carbon material was measured by using the small depleted uranium fission chamber and the capturing detector. For comparison, 238U fission rates without carbon material was measured too. The combined standard uncertainty of 238U fission reaction rate is 5.1%-6.4%. The measured results are consistent with the calculated ones with MCNP/4A code and ENDF/B-IV library data in the range of the error

  3. Experimental Determination of the Antineutrino Spectrum of the Fission Products of $^{238}$U

    CERN Document Server

    Haag, N; Hofmann, M; Oberauer, L; Potzel, W; Schreckenbach, K; Wagner, F M

    2013-01-01

    An experiment was performed at the scientific neutron source FRM II in Garching to determine the cumulative antineutrino spectrum of the fission products of $^{238}$U. This was achieved by irradiating target foils of natural uranium with a thermal and a fast neutron beam and recording the emitted $\\beta$-spectra with a gamma-suppressing electron-telescope. The obtained $\\beta$-spectrum of the fission products of $^{235}$U was normalized to the data of the magnetic spectrometer BILL of $^{235}$U. This method strongly reduces systematic errors in the $^{238}$U measurement. The $\\beta$-spectrum of $^{238}$U was converted into the corresponding antineutrino spectrum. The final $\\bar\

  4. A study of reaction rates of (n,f), (n,γ) and (n,2n) reactions in natU and 232Th by the neutron fluence produced in the graphite set-up (GAMMA-3) irradiated by 2.33 GeV deuteron beam

    International Nuclear Information System (INIS)

    Spallation neutrons produced in the collision of a 2.33GeV deuteron beam with a large lead target are moderated by a thick graphite block surrounding the target and used to activate the radioactive samples of natU and Th put at three different positions, identified as holes ''a'', ''b'' and ''c'' in the graphite block. Rates of the (n,f), (n,γ) and (n,2n) reactions in the two samples are determined using the gamma spectrometry. The ratios of the experimental reaction rates, R (n,2n)/R (n,f), for 232Th and natU are estimated in order to understand the role of the (n,x n) kind of reactions in Accelerator-Driven Sub-critical Systems. For the Th-sample, the ratio is ∝ 54 (10)% in the case of hole ''a'' and ∝ 95 (57)% in the case of hole ''b'' compared to 1.73(20)% for hole ''a'' and 0.710(9)% for hole ''b'' in the case of the natU sample. Also the ratio of fission rates in uranium to thorium, natU (n,f)/ 232Th (n,f), is ∝ 11.2 (17) in the case of hole ''a'' and 26.8(85) in hole ''b''. Similarly, the ratio 238U (n,2n)/ 232Th (n,2n) is 0.36(4) for hole ''a'' and 0.20(10) for hole ''b'' showing that 232Th is more prone to the (n,x n) reaction than 238U. All the experimental reaction rates are compared with the simulated ones by generating neutron fluxes at the three holes from MCNPX 2.6c and making use of the LA150 library of cross-sections. The experimental and calculated reaction rates of all the three reactions are in reasonably good agreement. The transmutation power, Pnorm as well as Pnorm/Pbeam of the set-up is estimated using the reaction rates of the (n, γ) and (n,2n) reactions for both the samples in the three holes and compared with some of the results of the ''Energy plus Transmutation'' set-up and TARC experiment. (orig.)

  5. Analysis of transmission experiments for 238U in the unresolved resonance region

    International Nuclear Information System (INIS)

    From analysis of experimental data on transmission in the region of unresolved resonances, an evaluation of the mean resonance parameters for 238U is obtained. These parameters do not contradict the corresponding evaluations from the region of resolved resonances. On the basis of this evaluation, the group constants for 238U are determined, for the region of unresolved resonances. A comparison is made with data tables

  6. 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.

  7. Procedures for determination of 239,240Pu, 241Am, 237Np, 234,238U, 228,230,232Th, 99Tc and 210Pb-210Po in environmental material

    International Nuclear Information System (INIS)

    Since 1987, the Department of Nuclear Safety Research, Risoe National Laboratory has developed procedures for analysis of low-level amounts of radioactivity in large samples of 200 liters seawater, 10 gram sediment, soil and other environmental materials. These analytical procedures provide high chemical yields, good resolution and excellent decontamination factors for large environmental samples analysed by alpha spectrometry and mass spectrometry (ICPMS). The procedures have been checked through practical analysis work and are used in Norway, the Netherlands, Germany, Spain, France and Denmark. (au)

  8. Fractionation of 238U/235U by reduction during low temperature uranium mineralisation processes

    Science.gov (United States)

    Murphy, Melissa J.; Stirling, Claudine H.; Kaltenbach, Angela; Turner, Simon P.; Schaefer, Bruce F.

    2014-02-01

    Investigations of ‘stable’ uranium isotope fractionation during low temperature, redox transformations may provide new insights into the usefulness of the 238U/235U isotope system as a tracer of palaeoredox processes. Sandstone-hosted uranium deposits accumulate at an oxidation/reduction interface within an aquifer from the low temperature reduction of soluble U(VI) complexes in groundwaters, forming insoluble U(IV) minerals. This setting provides an ideal environment in which to investigate the effects of redox transformations on 238U/235U fractionation. Here we present the first coupled measurements of 238U/235U isotopic compositions and U concentrations for groundwaters and mineralised sediment samples from the same redox system in the vicinity of the high-grade Pepegoona sandstone-hosted uranium deposit, Australia. The mineralised sediment samples display extremely variable 238U/235U ratios (herein expressed as δUCRM145238, the per-mil deviation from the international NBL standard CRM145). The majority of mineralised sediment samples have δUCRM145238 values between -1.30±0.05 and 0.55±0.12‰, spanning a ca. 2‰ range. However, one sample has an unusually light isotopic composition of -4.13±0.05‰, which suggests a total range of U isotopic variability of up to ca. 5‰, the largest variation found thus far in a single natural redox system. The 238U/235U isotopic signature of the mineralised sediments becomes progressively heavier (enriched in 238U) along the groundwater flow path. The groundwaters show a greater than 2‰ variation in their 238U/235U ratios, ranging from δUCRM145238 values of -2.39±0.07 to -0.71±0.05‰. The majority of the groundwater data exhibit a clear systematic relationship between 238U/235U isotopic composition and U concentration; samples with the lowest U concentrations have the lowest 238U/235U ratios. The preferential incorporation of 238U during reduction of U(VI) to U(IV) and precipitation of uranium minerals leaves

  9. Measurement of fission products yields in the quasi-mono-energetic neutron-induced fission of 232Th

    Science.gov (United States)

    Naik, H.; Mukherji, Sadhana; Suryanarayana, S. V.; Jagadeesan, K. C.; Thakare, S. V.; Sharma, S. C.

    2016-08-01

    The cumulative yields of various fission products in the 232Th(n, f) reaction at average neutron energies of 5.42, 7.75, 9.35 and 12.53 MeV have been determined by using an off-line γ-ray spectrometric technique. The neutron beam was produced from the 7Li(p, n) reaction by using the proton energies of 7.8, 12, 16 and 20 MeV. The mass chain yields were obtained from the cumulative fission yields by using the charge distribution correction of medium energy fission. The fine structure in the mass yield distribution was interpreted from the point of nuclear structure effect. On the other hand, the higher yield around mass number 133-134 and 143-144 as well as their complementary products were explained based on the standard I and standard II asymmetric mode of fission. From the mass yield data, the average value of light mass (), heavy mass (), the average number of neutrons () and the peak-to-valley (P / V) ratios at different neutron energies of present work and literature data were obtained in the 232Th(n, f) reaction. The different parameters of the mass yield distribution in the 232Th(n, f) reaction were compared with the similar data in the 232Th(γ, f) reaction at comparable excitation energy and a surprising difference was observed.

  10. Determination of 232Th, 230Th and 228Th in liquid effluents from uranium mining

    International Nuclear Information System (INIS)

    A liquid scintillator αlpha spectrometer was built for the determination of Th-228, Th-230 and Th-232 in liquid effluents from Uranium mines and mills. The resolution of the αlpha spectrometer was found to be 200-300 KeV, when the scintillator was 8% T0P0, 0,77% scintimix-4 (91% PP0 and 9% Dimetil-P0P0P) and 10% of naphthalene in toluene. Aliquat-336 in xylene (30% v/v) was used to separate the thorium isotopes from other interfering radionuclides (U-238, U-234, Ra-226, Po-210). Under the extraction experimental conditions, the detection limits were 1,2 pCi/1 for Th-232, 1,2 pCi/1 for Th-230 and 0,9 pCi/1 for Th-228, for 1000 minutes of counting time. (author)

  11. (234)U/(238)U signatures associated with uranium ore bodies: part 3 Koongarra.

    Science.gov (United States)

    Lowson, Richard T

    2013-04-01

    The Koongarra ore body is an early Proterozoic U ore body in the Alligator Rivers U province, Northern Territory, Australia. It has surface expression with a redox front located ∼30 m below the surface. The (234)U/(238)U activity ratios (AR) for the ground water and the amorphous phase of the solid have been analysed for the ore zone and dispersion halo as a function of depth. The results display a (234)U/(238)U AR signature with depth which may be common to all U ore bodies. The (234)U/(238)U AR is depressed below secular equilibrium in the weathered material above the redox front; rises significantly above secular equilibrium in the vicinity of the redox front; and is followed by a gradual decrease with depth below the redox front. The amplitude of the profile is a function of local conditions. A model is proposed for the signature in which oxidising waters preferentially leach the (234)U sites at the redox front due to preconditioning of the (234)U sites by α recoil during the decay of (23)(8)U to (23)(4)U. Mass balance requires the solid material left behind the redox front to have a (234)U/(238)U AR reduced below 1. Local second order effects may be superimposed on the signature. The signature may have application to calibrating scenarios for nuclear waste repositories, assisting in understanding historical climates, economic evaluation of U ore bodies and U exploration. PMID:23142336

  12. Transfer reaction cross sections from the interactions of 20Ne and 22Ne with 232Th

    International Nuclear Information System (INIS)

    A target of 232Th has been bombarded with 114 MeV 22Ne and with 114 MeV and 129 MeV 20Ne beams. Recoiling reaction products were chemically isolated and the cross sections for protactinium, uranium, and neptunium isotopes were determined. The width of the cross section distributions for a given Z and their neutron-richness are the same as those for similar transfers in Ne+ 248Cm reactions. Population of low spin isomeric states is favored in these reactions over population of high spin states. As was seen in reactions with heavier targets, an increase in reaction energy does little to shift the evaporation residues toward neutron deficiency. The implications are that only primary products with little or no excitation energy and angular momentum survive the fission process to become evaporation residues in these systems, and that the production of these nuclides is more controlled by the change in the identity of the projectile than by the corresponding change in the target

  13. Two-photon laser excitation of trapped 232Th+ ions via the 402 nm resonance line

    CERN Document Server

    Herrera-Sancho, O A; Zimmermann, K; Tamm, Chr; Peik, E; Taichenachev, A V; Yudin, V I; Glowacki, P

    2012-01-01

    Experiments on one- and two-photon laser excitation of 232Th+ ions in a radiofrequency ion trap are reported. As the first excitation step, the strongest resonance line at 402 nm from the 6d^2 7s J=3/2 ground state to the 6d7s7p J=5/2 state at 24874 cm^{-1} is driven by radiation from an extended cavity diode laser. Spontaneous decay of the intermediate state populates a number of low-lying metastable states, thus limiting the excited state population and fluorescence signal obtainable with continuous laser excitation. We study the collisional quenching efficiency of helium, argon, and nitrogen buffer gases, and the effect of repumping laser excitation from the three lowest-lying metastable levels. The experimental results are compared with a four-level rate equation model, that allows us to deduce quenching rates for these buffer gases. Using laser radiation at 399 nm for the second step, we demonstrate two-photon excitation to the state at 49960 cm^{-1}, among the highest-lying classified levels of Th+. Thi...

  14. Transmission Nuclear Resonance Fluorescence Measurements of 238U in Thick Targets

    Energy Technology Data Exchange (ETDEWEB)

    Quiter, Brian J.; Ludewigt, Bernhard A.; Mozin, Vladimir V.; Wilson, Cody; Korbly, Steve

    2010-08-31

    Transmission nuclear resonance fluorescence measurements were made on targets consisting of Pb and depleted U with total areal densities near 86 g/cm2. The 238U content n the targets varied from 0 to 8.5percent (atom fraction). The experiment demonstrates the capability of using transmission measurements as a non-destructive technique to identify and quantify the presence of an isotope in samples with thicknesses comparable to he average thickness of a nuclear fuel assembly. The experimental data also appear to demonstrate the process of notch refilling with a predictable intensity. Comparison of measured spectra to previous backscatter 238U measurements indicates general agreement in observed excited states. Two new 238U excited states and possibly a third state have also been observed.

  15. 238U, 226Ra and 210Pb in some vent waters of the Galapagos spreading center

    International Nuclear Information System (INIS)

    The concentrations of 226Ra, 238U and 210Pb have been measured in waters from the Mussel Bed and the Rose Garden thermal fields at the Galapagos spreading center over a temperature range of approx.2.5--16 0C. The 226Ra-T plots yield slopes of 0.112 and 0.036 dpm/kg 0C for the Mussel Bed and the Rose Garden respectively yielding a global hydrothermal 226Ra flux less than 5% of that required to sustain the oceanic inventory. 238U concentration in waters 0C is the same as that in ambient sea water whereas water hotter than approx.9 0C shows a decreasing trend with temperature to zero 238U at approx.29 0C. 210Pb concentration in Mussel Bed increases with temperature, and extrapolated to approx.350 0C yields a 210Pb concentration considerably less than that expected from 222Rn decay and basalt alteration

  16. Measurement of resonance self-shielding factors of neutron capture cross section by 238U

    International Nuclear Information System (INIS)

    Resonance self-shielding factors fsub(c) of neutron capture cross section by 238U in the 20-100 keV energy range are measured. The method for determining the fsub(c) factor consists in measuring partial transmission and transmission in the total cross section at different 238U filter thickness. The fsub(c) factor values in the 46.5-100 and 21.5-46.5 keV energy ranges are equal to 0.89+-0.03 and 0.81+-0.04, respectively

  17. Soil-to-root vegetable transfer factors for 226Ra, 232Th, 40K, and 88Y in Malaysia

    International Nuclear Information System (INIS)

    Soil-to-plant transfer factors (TFs) are of fundamental importance in assessing the environmental impact due to the presence of radioactivity in soil and agricultural crops. Tapioca and sweet potato, both root crops, are popular foodstuffs for a significant fraction of the Malaysian population, and result in intake of radionuclides. For the natural field conditions experienced in production of these foodstuffs, TFs and the annual effective dose were evaluated for the natural radionuclides 226Ra, 232Th, 40K, and for the anthropogenic radionuclide 88Y, the latter being a component of fallout. An experimental tapioca field was developed for study of the time dependence of plant uptake. For soil samples from all study locations other than the experimental field, it has been shown that these contain the artificial radionuclide 88Y, although the uptake of 88Y has only been observed in the roots of the plant Manihot esculenta (from which tapioca is derived) grown in mining soil. The estimated TFs for 226Ra and 232Th for tapioca and sweet potato are very much higher than that reported by the IAEA. For all study areas, the annual effective dose from ingestion of tapioca and sweet potato are estimated to be lower than the world average (290 μSv y−1). - Highlights: • Transfer factors of 226Ra, 232Th, 40K, and 88Y radionuclides were estimated for widely consumed root vegetables in Malaysia. • An experimental tapioca field was developed for study of the time dependence of plant uptakes. • The estimated TF values of 226Ra and 232Th for tapioca and sweet potato are higher than the IAEA reported values. • These site-specific TFs are of importance for model derivations for tropical regions

  18. {sup 226}Ra, {sup 232}Th and {sup 40}K concentrations in igneous rocks from eastern desert, Egypt and its radiological implications

    Energy Technology Data Exchange (ETDEWEB)

    El-Arabi, A.M. [Physics Department, Faculty of Science Qena, South Valley University (Egypt)]. E-mail: elarabi21@yahoo.com

    2007-01-15

    By applying high-resolution {gamma}-ray spectroscopic system, the various radionuclides of the granite samples have been identified quantitatively based on the characteristic spectral peaks. The radionuclides {sup 226}Ra, {sup 232}Th and {sup 40}K concentrations measured as well as radiological parameters, for 49 granite samples were calculated. This subject is important in environmental radiological protection, since granites are widely used as building and ornamental stones. The variation in concentration of radionuclides for the Um Taghir area can be classified into two regions of low and high natural radioactivity. In old granite, the measured {gamma}-ray spectra, activity concentrations were determined for {sup 226}Ra (from 2.9+/-1 to 31.8+/-6Bqkg{sup -1}), {sup 232}Th (range from 1.4+/-1 to 14.9+/-4Bqkg{sup -1}) and {sup 40}K (from 132+/-11 to 2080+/-46Bqkg{sup -1}), in younger granite {sup 226}Ra (from 8.9+/-3 to 9087+/-95Bqkg{sup -1}), {sup 232}Th (range from 9.8+/-3 to 3834+/-62Bqkg{sup -1}) and {sup 40}K (from 471+/-22 to 10230+/-101Bqkg{sup -1}). In Wadi Karim area these values were (14.0+/-4-227.0+/-15, 10.5+/-3-183.0+/-14 and 2299+/-48-7356+/-86Bqkg{sup -1}). The highest values of {sup 226}Ra, {sup 232}Th and {sup 40}K concentration (9087+/-95, 3834+/-62 and 10230+/-101Bqkg{sup -1},respectively) were observed in anomalies samples at Um Taghir region. Radium-equivalent activities (Ra{sub eq}) in addition to the internal hazard index (H{sub in}) have also been determined. In Um Taghir samples Ra{sub eq} varies between 15 and 625Bqkg{sup -1} (old granite), 144-13982Bqkg{sup -1} (younger granite) which exceeds the permitted value (370Bqkg{sup -1}) and hazard index (H{sub in}) (0.05-1.74), (0.65-62.34) which is higher than 1, the corresponding values in Wadi Karim samples were 206-685Bqkg{sup -1} and from 0.59 to 2.46, respectively. The total absorbed dose rates in air calculated from the concentrations of the three radionuclides ranged from 8 to 6187n

  19. Determination of 228Th, 232Th, and228Ra in wild mushroom from a naturally high radioactive region in Brazil

    International Nuclear Information System (INIS)

    Mushrooms are fungi which efficiently accumulate radionuclides, as verified by radiochemistry analyses of specimens collected in contaminated areas, specifically after the Chernobyl nuclear accident. Many studies have demonstrated that mushrooms can be used in monitoring of ecosystem contamination and quality. The present paper is part of a broader study conducted in the Pocos de Caldas plateau region in Minas Gerais, Brazil, investigating assimilation of natural Uranium and Thorium radionuclide series by mushrooms. This region has elevated natural radioactivity due to the presence of radiological anomalies of volcanic origin. These anomalies are ore bodies containing Uranium and Thorium, the later being highly predominant. Many researchers have been conducted concerning radionuclide incorporation by agricultural products on the plateau. The present paper aims to determine 232Th, 228Th, and 228Ra radionuclides in wild mushrooms collected at different locations in the plateau region. 228Ra was determined by radiochemical separation using sulphate coprecipitation followed by beta radiometry. 232Th and 228Th were determined using anion exchange resin purification followed by alpha spectrometry. Higher values were obtained to 228Th than to 232Th. This is due to higher 228Ra mobility, which decays to 228Th. The accuracy of the analytical methods employed was evaluated using the reference sample IAEA Soil 327. These methods had high chemical recovery and high sensitivity. It was possible to confirm that mushrooms accumulate radionuclide and so can be used in environmental contamination and quality assessment. (author)

  20. [About the contents of 40K, 226Ra and 232Th in forest soils of the Republic of Belarus].

    Science.gov (United States)

    Perevolotskiĭ, A N; Perevolotskaia, T V

    2014-01-01

    The specific activity of 40K, 232Th and 226Ra in forest soil ecotopes (A2-B2-C2-D2) has been investigated. When the fertility of the soil increases from A2 to D2, then the specific activity of 40K increases in the rooting zone of the soil from 275 ± 6.9 up to 499 ± 11 Bq/kg, 232Th--from 11.8 ± 0.5 to 17.1 ± 1.1 Bq/kg, 226Ra- from 19.2 γ 0.8 to 27.9 ± 1.5 Bq/kg. The calculated capacity of the absorbed dose of γ-radiation conditioned by 40K, 232Th and 226Ra increases from A2 to D2 from 27.5 ± 0.5 to 44.1 ± 1.1 nGy / h at the height of 1 m.

  1. 238U spontaneous fission half-life and a new probable radioactivity mode

    International Nuclear Information System (INIS)

    The 238U spontaneous fission half-life is reinvestigated using a special nuclear emulsion technique previously developed in our laboratory. A perfect visualisation of the fission fragments tracks in the absence of alpha particle tracks was obtained with the present method that also avoids the fading of the latent image. Under these conditions, two well defined peaks are observed experimentaly: one corresponding to the well-known range (approx 24 μm) of the 238U fission fragments tracks and the other showing evidence of short range tracks (approx 10 μm). For the 238U spontaneous fission half-life our result is (6.0+-0.4) x1015 y, in good agreement with the values obtained by some other workers using different experimental methods. A systematic theoretical analysis shows that the 238U spontaneous emission of nuclides with mass number between approx 20 e 70 is possible. The Kinetic energies calculated for these nuclides are found to fit the short range tracks observed in our experiment. From the experimental data, we attribute a (2 +- 1) x 1015 y half-life for all modes of emission involved in this process. (Author)

  2. Energy dependence of 238U fission yields investigated in inverse kinematics

    Directory of Open Access Journals (Sweden)

    Veselsky M.

    2010-03-01

    Full Text Available The production cross sections of neutron-rich fission residues produced in reactions induced by a 238U beam impinging onto Pb and Be targets were investigated at the Fragment Separator (FRS at GSI using the inverse kinematic technique. These data allowed us to discuss the optimum energies in fission for producing the most neutron-rich residues.

  3. Radiochemical measurement of mass distribution in 16O+238U reaction at sub-barrier energy

    International Nuclear Information System (INIS)

    In the present, radiochemical study of the mass distribution in 16O+238U has been carried out at sub-barrier energy to investigate the nature of mass distribution in CFF and TF channels. In addition, cross sections of evaporation residues formed in one nucleon transfer/pick-up reactions have also been measured

  4. Study of fusion-fission dynamics in 19F+238U reaction

    Directory of Open Access Journals (Sweden)

    Dubey R.

    2016-01-01

    Full Text Available Mass angle distribution measurements for 19F+238U reaction were carried out around the sub barrier energies. Mass angle correlation has not been observed at above and below the fusion barrier in present reaction. This infer the minimal presence of non compound like events at these bombarding energies range.

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

    International Nuclear Information System (INIS)

    LLNL Internal Dosimetry Program - The new procedure satisfies the requirement to determine 235U/238U ratio in bioassay urine samples. MDA - The LC and MDA95 for 235U are well below the required detection limit of 0.00035 μg/L. Turn around time - Analysis of 10 samples plus 2 QCs can be completed in one work day (8 hours).

  6. Magmatic Processes at Loihi Seamount Inferred From 226Ra-230Th-234U-238U Disequilibria

    Science.gov (United States)

    Pietruszka, A. J.; Hauri, E. H.; Garcia, M. O.

    2001-12-01

    We have conducted a detailed study of the U-series isotope geochemistry of young tholeiitic, transitional and alkalic Loihi basalts to examine the melt generation process during the preshield stage of a Hawaiian volcano. A previous study (Sims et al. 1999; GCA, v. 63) of two dredged lavas from the deep flanks of Loihi found a higher (230Th/238U) activity ratio in an alkalic basalt (1.07) compared to a tholeiitic basalt (1.04). This difference suggests that the tholeiitic basalt may have formed at a higher rate of mantle upwelling than the alkalic basalt. Our samples were collected from surface lava flows at Loihi's summit and along the volcano's south rift zone by submersible. Analyses were preformed using high-precision plasma ionization mass spectrometry. The samples display a relatively large range in the amount of excess 226Ra (0-13%) that extends to much lower values than observed at Kilauea Volcano (11-12%). The low (226Ra/230Th) ratios of Loihi lavas probably result from post-eruptive decay of 226Ra and imply eruption ages of 0-12 kyr. All of the Loihi samples (including the 1996 lava) have small amounts of excess 234U (0.2-0.8%). The most likely source for (234U/238U)>1 at Loihi is seawater, which has (234U/238U)=1.14. Since all of the samples were fresh, hand-picked glasses, these elevated (234U/238U) ratios may have resulted from the assimilation of a seawater-derived component within Loihi's magmatic plumbing system rather than post-eruptive U addition. The range of (230Th/238U) that we measured is 1.01-1.07, which is larger than the previous range known for Loihi. Mass balance calculations using the measured (234U/238U) ratios suggest that 1-6% of the U in the samples that we analyzed is ultimately derived from seawater. Correcting the 230Th-238U disequilibria of the Loihi lavas for this seawater-derived U results in a narrower range in the amount of excess 230Th (6-9%) with no significant differences between tholeiitic, transitional or alkalic basalts

  7. Experimental study of 238U Doppler reactivity worth in FCA XVI-1 and XVI-2 cores

    International Nuclear Information System (INIS)

    Doppler reactivity worths of natural uranium samples were measured in metallic fueled cores, FCA XVI-1 and XVI-2, using a sample heating technique. In a metallic fueled LMFBR, the neutron spectrum is generally harder than a similar size oxide fueled LMFBR owing to the luck of oxygen. The accuracy of Doppler effect calculation for a harder neutron spectrum was evaluated by comparing C/E values of Doppler reactivity worth in oxide fueled cores and in metallic fueled cores using FCA experiments. It was found that calculation using 70-group constant set JFS-3-J2 underestimates 238U Doppler reactivity worth in metallic fueled cores. An inadequate treatment of resonance parameters of 238U above 50 keV in JENDL-2 is one of the reasons for this underestimation. In JENDL-2 the resonance parameters of 238U above 50 keV are not included, and hence JFS-3-J2 which is processed from JENDL-2 does not have a self-shielding factor table above 40.9 keV of 238U. When the contribution of this energy region for Doppler reactivity worth was corrected using ENDF/B-VI, which includes resonance parameters of 238U up to 149 keV, the JFS-3-J2 based calculation gave 13% higher values for metallic sample experiments and 8% for oxide samples. Even after this correction, the calculation still gave smaller Doppler reactivity worths than the measurements, and the ratios of calculated value to experimental one vary widely from 0.6 to 1.0. (author)

  8. Studying nuclear level densities of {sup 238}U in the nuclear reactions within the macroscopic nuclear models

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, Rohallah; Aghajani, Maghsood; Khooy, Asghar [Imam Hossein Comprehensive Univ., Tehran (Iran, Islamic Republic of). Dept. of Physics; Rahmatinejad, Azam; Taheri, Fariba [Univ. of Zanjan (Iran, Islamic Republic of). Dept. of Physics; Kakavand, Tayeb [Imam Khomeini International Univ., Qazvin (Iran, Islamic Republic of). Dept. of Physics

    2016-05-01

    In this work the nuclear level density parameters of {sup 238}U have been extracted in the back-shifted Fermi gas model (BSFGM), as well as the constant temperature model (CTM), through fitting with the recent experimental data on nuclear level densities measured by the Oslo group. The excitation functions for {sup 238}U(p,2nα){sup 233}Pa, and {sup 238}U(p,4n){sup 235}Np reactions and the fragment yields for the fragments of the {sup 238}U(p,f) reaction have been calculated using obtained level density parameters. The results are compared to their corresponding experimental values. It was found that the extracted excitation functions and the fragment yields in the CTM coincide well with the experimental values in the low-energy region. This finding is according to the claim made by the Oslo group that the extracted level densities of {sup 238}U show a constant temperature behaviour.

  9. 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

  10. 238U self-indication ratio measurement in the resonance region

    International Nuclear Information System (INIS)

    An accurate representation of the 238U cross-section structures in the resonance region is required to compute the resonance self-shielded effective cross sections used in the calculation of thermal and fast-reactor performance parameters. Several authors have demonstrated the usefulness of self-indication and average transmission measurements to investigate the resonance structure of the 238U cross sections. This paper compares measured self-indication ratios with calculations based on ENDF/B-V, in the resolved energy range from 100 eV to 4 keV. In that energy range the ENDF/B-V evaluation is chiefly based on high resolution transmission measurements. The immediate purpose of the comparison presented is not to generate a new set of improved resonance parameters but to provide an additional test of the adequacy of the ENDF/B-V representation for the calculation of resonance self-shielding

  11. Comparison of Yields of neutron rich nuclei in Proton and Photon induced $^{238}$U fission

    CERN Document Server

    Khan, F A; Basu, D N; Farooq, M; Chakrabarti, Alok

    2016-01-01

    A comparative study of fission of actinides specially $^{238}$U, by proton and bremsstrahlung photon is performed. Relative mass distribution of $^{238}$U fission fragments have been explored theoretically for both proton and photon induced fission. The integrated yield along with charge distribution of the products are calculated to find out the neutron richness in comparison to the nuclei produced by r-process in nucleosynthesis. Some r-process nuclei in intermediate mass range for symmetric fission mode are found to be produced almost two order of magnitude more for proton induced fission than photofission, although rest of the neutron rich nuclei in the asymmetric mode are produced in comparable proportion for both the processes.

  12. Exploring the multi-humped fission barrier of 238U via sub-barrier photofission

    CERN Document Server

    Csige, L; Glodariu, T; Gulyás, J; Günther, M M; Habs, D; Karwowski, H J; Krasznahorkay, A; Rich, G C; Sin, M; Stroe, L; Tesileanu, O; Thirolf, P G

    2013-01-01

    The photofission cross-section of 238U was measured at sub-barrier energies as a function of the gamma-ray energy using, for the first time, a monochromatic, high-brilliance, Compton-backscattered gamma-ray beam. The experiment was performed at the High Intensity gamma-ray Source (HIgS) facility at beam energies between E=4.7 MeV and 6.0 MeV and with ~3% energy resolution. Indications of transmission resonances have been observed at gamma-ray beam energies of E=5.1 MeV and 5.6 MeV with moderate amplitudes. The triple-humped fission barrier parameters of 238U have been determined by fitting EMPIRE-3.1 nuclear reaction code calculations to the experimental photofission cross section.

  13. Exploring the multihumped fission barrier of 238U via sub-barrier photofission

    Science.gov (United States)

    Csige, L.; Filipescu, D. M.; Glodariu, T.; Gulyás, J.; Günther, M. M.; Habs, D.; Karwowski, H. J.; Krasznahorkay, A.; Rich, G. C.; Sin, M.; Stroe, L.; Tesileanu, O.; Thirolf, P. G.

    2013-04-01

    The photofission cross section of 238U was measured at sub-barrier energies as a function of the γ-ray energy using a monochromatic, high-brilliance, Compton-backscattered γ-ray beam. The experiment was performed at the High Intensity γ-ray Source (HIγS) facility at beam energies between Eγ=4.7 MeV and 6.0 MeV and with ˜3% energy resolution. Indications of transmission resonances have been observed at γ-ray beam energies of Eγ=5.1 MeV and 5.6 MeV with moderate amplitudes. The triple-humped fission barrier parameters of 238U have been determined by fitting empire-3.1 nuclear reaction code calculations to the experimental photofission cross section.

  14. Development of a method for activity measurements of {sup 232}Th daughters with a multidetector gamma-ray coincidence spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Antovic, N. [Faculty of Natural Sciences and Mathematics, University of Montenegro, Cetinjski put b.b., 81000 Podgorica (Montenegro)], E-mail: antovicn@yahoo.com; Svrkota, N. [Center for Ecotoxicological Research, Put Radomira Ivanovica 2, 81000 Podgorica (Montenegro)

    2009-06-15

    The method for activity measurements of the {sup 232}Th daughters, developed at the six-crystal gamma-ray coincidence spectrometer PRIPYAT-2M and based on coincidence counting of the 583 and 2615 keV photons from cascade transitions which follow {beta}{sup -}-decay of {sup 208}Tl, as well as on counting the 911 keV photons which follow {beta}{sup -}-decay of {sup 228}Ac in the integral and non-coincidence mode of counting, is presented.

  15. 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)

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

    International Nuclear Information System (INIS)

    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 235U and 239Pu by Ganesan and by Antsipov et al; similar sensitivity studies for 238U are reported

  17. An Analysis of 178Pb to 238U Isotopes with the Universal and Yukawa Proximity Potentials

    Science.gov (United States)

    Javadimanesh, E.; Hassanabadi, H.; Zarrinkamar, S.

    2013-07-01

    The alpha particle preformation and the penetration probability by the Yukawa proximity potential in the even-even nuclei from 178Pb to 238U are studied. Using the experimental values of the alpha decay half-lives and the decay energies, we extract the preformation factors and the penetration probabilities. We also calculate the assault frequencies and the decay constants. The obtained results are motivating.

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

    OpenAIRE

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

    2011-01-01

    The vertical distribution of the 236U/238U isotopic ratio was investigated in soil samples from three different locations on La Palma (one of the seven Canary Islands, Spain). Additionally the 240Pu/239Pu atomic ratio, as it is a well establish tool for the source identification, was determined. The radiochemical procedure consisted of a U separation step by extraction chromatography using UTEVA® Resin (Eichrom Technologies, Inc.). Afterwards Pu was separated from Th and Np by anion exchange ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-19

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

  20. 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.

  1. 238U, 226Ra and 210Pb in some vent waters of the Galapagos Spreading Center

    Science.gov (United States)

    Krishnaswami, S.; Turekian, K. K.

    1982-08-01

    The concentrations of 226Ra, 238U and 210Pb have been measured in waters from the Mussel Bed and the Rose Garden thermal fields at the Galapagos spreading center over a temperature range of ˜2.5-16°C. The 226Ra-T plots yield slopes of 0.112 and 0.036 dpm/kg°C for the Mussel Bed and the Rose Garden respectively yielding a global hydrothermal 226Ra flux less than 5% of that required to sustain the oceanic inventory. 238U concentration in waters <9°C is the same as that in ambient sea water whereas water hotter than ˜9°C shows a decreasing trend with temperature to zero 238U at ˜29°C. 210Pb concentration in Mussel Bed increases with temperature, and extrapolated to ˜350°C yields a 210Pb concentration considerably less than that expected from 222Rn decay and basalt alteration.

  2. 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.

  3. Uranium content and 235U/238U isotopic ratio in dental porcelain powders determined by neutron activation analysis

    International Nuclear Information System (INIS)

    The uranium contents and 235U/238U isotopic ratios in 48 dental porcelain powders of 8 brands marketed in Japan were determined by non-destructive neutron activation analysis. The photopeak counts of 277.6 keV of 239Np formed by the 238U(n,γ)239U (yield to)239Np + β- reaction and at 1.595.2 keV of 140La produced by 235U fission were measured with a Ge(Li) semiconductor detector system to determine the uranium content and 235U/238U isotopic ratio. The results of the analysis are tabulated and their significance discussed. (author)

  4. Spins of resonances in reactions of neutrons with (238)U and (113)Cd. Doctoral thesis; Spins van resonanties in reacties van neutronen met (238)u en (113)cd

    Energy Technology Data Exchange (ETDEWEB)

    Gunsing, F.

    1994-12-31

    In this thesis experiments are described that have lead to the assignments of spins to a large number of resonances in reactions of epithermal neutrons with the nuclei (238)U and (113)Cd. When a neutron is captured by an atomic nucleus, a compound nucleus is formed which is in a highly excited state with an energy of the order of the neutron binding energy. If the kinetic neutron energy is varied around a state of the compound nucleus, one observes a peak in the cross section. This is called a resonance in the reaction. Dependent on the amount or orbital momentum l that the neutron adds to the system, the resonances are indicated with spectroscopic notations as s- and p-waves for l = 0 and 1 respectively. The purpose of this thesis is to determine the spins of such resonances.

  5. An integral experiment on thorium oxide/depleted uranium cylinders with D-T neutrons for 232Th(n, 2n) reaction

    International Nuclear Information System (INIS)

    Highlights: • An integral experiment for 232Th(n, 2n) reaction was carried out on the newly-established ThO2/depleted uranium cylinders. • 232Th(n, 2n) reaction rate distribution was obtained in the assemblies with an uncertainty of about 7%. • Experiments were analyzed by MCNP code with ENDF/B-VI.8, ENDF/B-VII.0, JENDL-4.0 and CENDL-3.1 libraries. • Experimental results could be used to re-evaluate the cross sections of 232Th(n, 2n) reaction. - Abstract: In order to verify the evaluated cross sections of 232Th(n, 2n) reaction for the conceptual design of the thorium based subcritical blanket in the fusion–fission hybrid reactor, an integral experiment on thorium oxide/depleted uranium cylinders was carried out with D-T neutrons using the activation technique. 232Th(n, 2n) reaction rate distribution was obtained at the central axis direction in the assemblies with an uncertainty of about 7%. Experiments were analyzed by using MCNP code with ENDF/B-VI.8, ENDF/B-VII.0, JENDL-4.0 and CENDL-3.1 libraries to validate the nuclear data libraries of 232Th(n, 2n) reaction, the calculated results with JENDL-4.0 agree with the measurements the best with discrepancies within the experimental uncertainty. The average values of C/E for the three benchmark assemblies are 1.058, 1.044 and 0.980. Calculations with different evaluated libraries in the benchmark assemblies show a large discrepancy. The experimental results can be used to re-evaluate the cross sections of the 232Th(n, 2n) reaction

  6. Isotope fractionation of 238U and 235U during biologically-mediated uranium reduction

    Science.gov (United States)

    Stirling, Claudine H.; Andersen, Morten B.; Warthmann, Rolf; Halliday, Alex N.

    2015-08-01

    A series of laboratory-controlled microbial experiments using gram-negative sulphate-reducing bacteria (Desulfovibrio brasiliensis) inoculated with natural uranium were performed to investigate 238U/235U fractionation during bacterially-mediated U reduction. Control experiments, without bacteria to drive U reduction, were conducted in parallel. Paired measurements of 238U/235U and U concentration for both the residual growth medium solution and the accumulated biologically-mediated precipitate were obtained using multiple-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The control experiments show that only minor (<0.1‰), if any 238U/235U fractionation occurs during co-precipitation with calcite. This implies that carbonate sediments are capable of faithfully recording the signature of the global ocean during Earth's major climatic events, including oxygenation and de-oxygenation transitions in the marine environment. The results for the microbial experiments demonstrate that the 238U/235U composition of the unreacted growth medium containing U(VI) is isotopically lighter than the composition of the U(IV)-bearing precipitate as U(VI) is consumed, in agreement with field-based observations of microbially-mediated U reduction. Uranium isotopic shifts of up to 0.8‰ were observed between the liquid and solid phases. These observations can be modelled using a Rayleigh distillation approach describing kinetic uptake in a closed system, which yields a fractionation factor α of 0.99923 ± 0.00004 (ε = -0.77 ± 04‰) for U(VI)-U(IV) reduction mediated by the D. brasiliensis microbe. This fractionation behaviour is consistent with that observed in field-based redox environments, which give rise to similar α values. Competing processes such as U co-precipitation (e.g. adsorption) may act to lower the apparent value for α and possibly play a secondary role both in the microbial experiments of this study and in natural U reduction settings where

  7. Investigation of resonance structure and Doppler-effect of cross sections for 232 Th, 235 U and 239 Pu

    International Nuclear Information System (INIS)

    The results of measuring the neutron transmissions for 232 Th, 235 U and 239 Pu metal samples carried out at the 60 m, 123 m and 1006 m flight paths of the Dubna IBR-30 booster in the neutron energy range of 2 eV - 200 keV are given and discussed. The measurements were made at the room and liquid nitrogen temperatures. The batteries of 3 boron and 26 helium counters were used as detectors. The results of the calculations of analogous transmissions realized on the base of the evaluated data libraries BROND-2, ENDF/B-6 and JENDL-3 by means of the GRUCON computer program package are also given. It is concluded that the 235 U Doppler coefficients and effective total cross sections taken from measured transmissions are in a good agreement with calculation results based on the ENDF/B-6 library at energies of 2.15 eV - 200 keV. The BROND-2 and JENDL-3 parameters give the Doppler coefficients and effective cross sections which are 10-30% higher than the experimental and ENDF/B-6 ones at the resonance energies of 46.5 - 465 eV. For 239 Pu there is agreement of the experimental and calculational results within the experimental error limits. For 232 Th experimental values for the Doppler coefficients and effective cross sections are 10-15% higher than the calculated ones with all libraries in resonance energy region. 9 refs., 2 tabs., 1 fig

  8. 8Dim calculations of the third barrier in $^{232}$Th and a conflict between theory and experiment on uranium nuclei

    CERN Document Server

    Jachimowicz, P; Skalski, J

    2013-01-01

    We find the height of the third fission barrier $B_{III}$ and energy of the third minimum $E_{III}$ in $^{232}$Th using the macroscopic - microscopic model, very well tested in this region of nuclei. For the first time it is done on an 8-dimensional deformation hypercube. The dipole distortion is included among the shape variables to assure that no important shapes are missed. The saddle point is found on a lattice containing more than 50 million points by the immersion water flow (IWF) method. The shallow third minimum, $B_{III}-E_{III}\\approx 0.36$ MeV, agrees with experimetal data of Blons et al. This is in a sharp contrast with the status of the IIIrd minima in $^{232-236}$U: their experimental depth of $\\geq3$ MeV contradicts all realistic theoretical predictions. We emphasize the importance of repeating the experiment on $^{232}$Th, by a technique similar to that used in the uranium nuclei, for settling the puzzle of the third minima in actinides.

  9. Generation of 238U Covariance Matrices by Using the Integral Data Assimilation Technique of the CONRAD Code

    Directory of Open Access Journals (Sweden)

    Privas E.

    2016-01-01

    Full Text Available A new IAEA Coordinated Research Project (CRP aims to test, validate and improve the IRDF library. Among the isotopes of interest, the modelisation of the 238U capture and fission cross sections represents a challenging task. A new description of the 238U neutrons induced reactions in the fast energy range is within progress in the frame of an IAEA evaluation consortium. The Nuclear Data group of Cadarache participates in this effort utilizing the 238U spectral indices measurements and Post Irradiated Experiments (PIE carried out in the fast reactors MASURCA (CEA Cadarache and PHENIX (CEA Marcoule. Such a collection of experimental results provides reliable integral information on the (n,γ and (n,f cross sections. This paper presents the Integral Data Assimilation (IDA technique of the CONRAD code used to propagate the uncertainties of the integral data on the 238U cross sections of interest for dosimetry applications.

  10. The inflow of uranium 234U and 238U from the Vistula River catchment area to the Baltic Sea

    International Nuclear Information System (INIS)

    In the study, the activities of uranium 234U and 238U in the Vistula River water samples which were collected from November 2002 to October 2003, were measured using alpha spectrometry. In winter, the highest concentration of uranium isotopes and total uranium was in the Vistula River water from Malbork (13.13 ± 0.22 Bq m-3 for 234U, 12.45 ± 0.21 Bq m-3 for 238U and 1.02 ± 0.30 mg m-3 for total uranium), and the lowest was in water from Deblin (1.73 ± 0.07 Bq m-3 for 234U, 1.55 ± 0.07 Bq m-3 for 238U and 0.13 ± 0.09 mg m-3 for total uranium). In analyzed river samples uranium isotopes 234U and 238U are not in the radioactive equilibrium state. The values of 234U/238U activity ratio lie between 1.05-1.70. During spring, the highest concentration of uranium isotopes and total uranium was found in the Vistula River water from Malbork (12.36 ± 0.19 Bq m-3 for 234U, 10.77 ± 0.17 Bq m-3 for 238U and 0.88 ± 0.25 mg m-3 for total uranium), and the lowest was in water taken from Sandomierz (5.77 ± 0.14 Bq m-3 for 234U) and Krakow (4.08 ± 0.11 Bq m-3 for 238U and 0.33 ± 0.18 mg m-3 for total uranium). The values of 234U/238U activity ratio lie between 1.15-1.64. In summer, the highest concentration of uranium isotopes and total uranium was found in the Vistula River water samples taken from Malbork (8.22 ± 0.21 Bq m-3 for 234U, 7.60 ± 0.21 Bq m-3 for 238U and 0.62 ± 0.29 mg m-3 for total uranium), and the lowest was in water from Sandomierz (6.37 ± 0.12 Bq m-3 for 234U) and Krakow (3.56 ± 0.19 Bq m-3 for 238U and 0.29 ± 0.33 mg m-3 for total uranium). The values of 234U/238U activity ratio lie between 1.08-1.95. In autumn the highest concentration of uranium isotopes and total uranium was in the Vistula River water from Malbork (17.80 ± 0.25 Bq m-3 for 234U, 15.12 ± 0.23 Bq m-3 for 238U and 1.23 ± 0.34 mg m-3 for total uranium) and the lowest was in water from Torun (8.15 ± 0.49 Bq m-3 for 234U) and Krakow (6.34 ± 0.47 Bq m-3 for 238U and 0.52 ± 0

  11. Generation of 238U Covariance Matrices by Using the Integral Data Assimilation Technique of the CONRAD Code

    Science.gov (United States)

    Privas, E.; Archier, P.; Bernard, D.; De Saint Jean, C.; Destouche, C.; Leconte, P.; Noguère, G.; Peneliau, Y.; Capote, R.

    2016-02-01

    A new IAEA Coordinated Research Project (CRP) aims to test, validate and improve the IRDF library. Among the isotopes of interest, the modelisation of the 238U capture and fission cross sections represents a challenging task. A new description of the 238U neutrons induced reactions in the fast energy range is within progress in the frame of an IAEA evaluation consortium. The Nuclear Data group of Cadarache participates in this effort utilizing the 238U spectral indices measurements and Post Irradiated Experiments (PIE) carried out in the fast reactors MASURCA (CEA Cadarache) and PHENIX (CEA Marcoule). Such a collection of experimental results provides reliable integral information on the (n,γ) and (n,f) cross sections. This paper presents the Integral Data Assimilation (IDA) technique of the CONRAD code used to propagate the uncertainties of the integral data on the 238U cross sections of interest for dosimetry applications.

  12. Element enrichment and U-series isotopic characteristics of the hydrothermal sulfides at Jade site in the Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The geochemical and U-series isotopic characteristics of hydrothermal sulfide samples from the Jade site (127°04.5′E, 27°15′N, water depth 1300-1450 m) at Jade site in the Okinawa Trough were analyzed. In the hydrothermal sulfide samples bearing sulfate (samples HOK1 and HOK2), the LREEs are relatively enriched. All the hydrothermal sulfide samples except HOK1 belong to Zn-rich hydrothermal sulfide. In comparison with Zn-rich hydrothermal sulfides from other fields, the contents of Zn, Pb, Ag, Cd, Au and Hg are higher, the contents of Fe, Al, Cr, Co, Ni, Sr, Te, Cs, Ti and U lower, and the 210Pb radioactivity ratios and 210Pb/Pb ratios very low. In the hydrothermal sulfide mainly composed of sphalerite, the correlations between rare elements Hf and U, and Hf and Mn as well as that between dispersive elements Ga and Zn, are strongly positive; also the contents of Au and Ag are related to Fe-sulfide, because the low temperature promotes enrichment of Au and Ag. Meanwhile, the positive correlations between Fe and Bi and between Zn and Cd are not affected by the change of mineral assemblage. Based on the 210Pb/Pb ratios of hydrothermal sulfide samples (3.99×10-5-5.42×10?5), their U isotopic composition (238U content 1.15-2.53 ppm, 238U activity 1.07-1.87 dpm/g, 234U activity 1.15-2.09 dpm/g and 234U/238U ratio 1.07-1.14) and their 232Th and 230Th contents are at base level, and the chronological age of hydrothermal sulfide at Jade site in the Okinawa Trough is between 200 and 2000 yr.

  13. Monte Carlo and deterministic simulations of activation ratio experiments for 238U(n,f), 238U(n,g) and 238U(n,2n) in the Big Ten benchmark critical assembly

    Energy Technology Data Exchange (ETDEWEB)

    Descalle, M; Clouse, C; Pruet, J

    2009-07-28

    The authors have compared calculations of critical assembly activation ratios using 3 different Monte Carlo codes and one deterministic code. There is excellent agreement. Discrepancies between the different Monte Carlo codes are the 1-2% level. Notably, the deterministic calculations with 87 groups are also in good agreement with the continuous energy Monte Carlo results. The three codes underestimate the {sup 238}U(n,f) reaction, suggesting that there is room for improvement in the evaluation, or in the evaluations of other reactions influencing the spectrum in BigTen. Until statistical uncertainties are implemented in Mercury, they strongly advise long runs to guarantee sufficient convergence of the flux at high energies, and they strongly encourage comparing Mercury results to a well-developed and documented code such as MCNP5 and/or COG. It may be that ENDL2008 will be available for use in COG within a year. Finally, it may be worthwhile to add a 'standard' reaction rate tally similar to those implemented in COG and MCNP5, if the goal is to expand the central fission and activation ratios simulations to include isotopes that are not part of the specifications for the assembly material composition.

  14. Absolute fission rate measurement of 238U induced by 14 MeV neutrons penetrated composite material

    International Nuclear Information System (INIS)

    In order to prove the model calculation method and parameter, the 238U absolute fission rate in the case of 14 MeV neutrons penetrating through the special composite material was measured by minitype slab uranium fission chambers. The measuring spots are distributed in the surface of iron ball hull along the different position of equator. The calculated results are compared with the experiment results. The total error of measured 238U absolute fission rate is 6.1%. (author)

  15. Potential Energy Surfaces of the Even-Even 230-238 U Isotopes

    Directory of Open Access Journals (Sweden)

    Diab S. M.

    2008-07-01

    Full Text Available Nuclear structure of 230 - 238 U isotopes have been studied in the frame work of the in- teracting boson approximation model (IBM-I. The contour plot of the potential energy surfaces, V ( ; , shows that all nuclei are deformed and have rotational char- acters, SU (3 . Levels energy spectra belonging to the gsb , , bands, electromagnetic transition rates B ( E 1 and B ( E 2 , quadrupole moment Q 0 , deformation parameterare 2 and the strength of the electric monopole transitions X ( E 0 =E 2 are calculated. The calculated values are compared with the available theoretical and experimental data and show reasonable agreement.

  16. Evaluation of resonance self-shielding factors for 238U in the unresolved resonance region

    International Nuclear Information System (INIS)

    On the basis of a theoretical model of identical equidistant resonances for the energy dependence of cross-sections in the unresolved resonance region, the authors have parametrized the values of the resonance self-shielding factors and their Doppler increments for 238U. They have proposed a method by which the Doppler increments of the self-shielding factors can be calculated from simple analytical formulae by redetermination of the model parameters. Analysing the experimental data on direct and capture transmissions in the unresolved resonance region, they demonstrate the possibility of describing those data as a whole and of deriving from them the cross-section group functionals. (author)

  17. Measurement of neutron-transmission spectra through 232Th from 8 MeV to 4 keV

    International Nuclear Information System (INIS)

    Neutron transmission spectra through room-temperature 232Th samples have been measured by use of the time-of-flight technique, the ORELA pulsed neutron source, and a 1-mm-thick Li-glass detector. The measurement and data reduction are described in detail. The 40-m transmission spectra through eight samples are directly compared from 15 to 4000 eV with resolution-broadened transmission spectra calculated from the ENDF/B-V total cross section. Two sets of 22-m transmission spectra through five samples are combined into one total cross section from 0.008 to 15.0 eV and compared with the ENDF/B-V evaluation. 13 figures, 12 tables

  18. Challenges and solutions for random sampling of parameters with extremely large uncertainties and analysis of the 232Th resonance covariances

    International Nuclear Information System (INIS)

    Covariance data in the existing evaluated nuclear data libraries often include large relative uncertainties and mathematical inconsistencies, which arise especially in combination with random sampling. The 232Th evaluation from the ENDF/B-VII.1 library has been taken as an example. Possible solutions for mathematically impossible correlation matrices with negative eigenvalues and too low correlation coefficients between inherently positive parameters with large relative uncertainties are proposed. Convergence of the random sampling for lognormal distribution with extremely high relative standard deviations is slow by nature. Using weighted sampling, single parameters or a limited number of correlated parameters with large uncertainties can be sampled. Efficient sampling of a large number of correlated parameters with extremely large relative uncertainties remains unsolved

  19. Detection efficiencies of 226Ra and 232Th in different modes of counting of the PRIPYAT-2M spectrometer

    Directory of Open Access Journals (Sweden)

    Antović Nevenka M.

    2009-01-01

    Full Text Available Detection efficiencies of 226Ra and 232Th decay products, as well as corresponding minimum detectable activities in different modes of counting of the PRIPYAT-2M spectrometer (integral, when all pulses - coincident and non-coincident, are counted; non-coincident, when only non-coincident pulses are counted; coincident, when coincident pulses of multiplicity from 2 to 6 are counted, in energy ranges of 200 keV to 2000 keV and 300 keV to 3000 keV are presented here. It has been shown that the mode of double coincidences is the optimum one for measuring radium and thorium activity. In this mode of counting, the sensitivity of the spectrometer is the highest.

  20. Origin and geochemical behavior of uranium in marine sediments. Utilization of the 234U/238U ratio in marine geochemistry

    International Nuclear Information System (INIS)

    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 234U/238U 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 234U/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

  1. The dependence of cumulative 238U(n,f) fission yield on incident-neutron energy

    Institute of Scientific and Technical Information of China (English)

    ZHENG Na; ZHONG Chunlai; MA Liyong; CHEN Zhongjing; LI Xiangqing; LIU Tingjin; CHEN Jinxiang; FAN Tieshuan

    2009-01-01

    This work is aim at studying the dependence of fission yields on incident neutron energy,so as to produce evaluated yield sets of the energy dependence.Experimental data at different neutron energies for gas fission products 85m,87,88Kr and 138Xe resulting from the 238U(n,f) reaction are processed using codes AVERAGE for weighed average and ZOTT for simultaneous evaluation.Energy dependence of the cumulative fission product yields on the incident neutron is presented.The evaluated curve of product yield is compared with the results calculated by the TALYS-0.64 code.The present evaluation is consistent with other main libraries in error permission.The fit curve of 87,88Kr can be recommended to predict the unmeasured fission yields.Comparisons of the evaluated energy dependence curves with theoretical calculated results show that the predictions using purely theoretical model for the fission process are not sufficiently accurate and reliable for the calculations of the cumulative fission yields for the 238U(n,f).

  2. (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.

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

    International Nuclear Information System (INIS)

    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 230Th was preferentially retained over either 234U or 238U 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 234U and 238U 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 230Th. 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 230Th in ore dust is questioned

  4. Distribution of 226Ra, 232Th and 40K in soils and sugar cane crops at Corumbatai river basin, Sao Paulo State, Brazil

    International Nuclear Information System (INIS)

    The common use of phosphate fertilizers NPK and amendments in sugar cane crops in Brazilian agriculture may increase the 226Ra, 232Th and 40K activity concentrations in soils and their availability for plants and human food chain. Thus, the main aim of this study was to evaluate the distribution of 226Ra, 232Th and 40K in soils and sugar cane crops in the Corumbatai river basin, Sao Paulo State, Brazil. The gamma spectrometry was utilized to measure the 226Ra, 232Th and 40K activity concentration in all samples. The soil-to-sugar cane transfer factors (TF) were quantified using the ratio between the radionuclide activity concentration in sugar cane and its activity concentration in soil. The results show that, although radionuclides incorporated in phosphate fertilizers and amendments are annually added in the sugar cane crops, if utilized in accordance with the recommended rates, their use does not lead to hazards levels in soils. The soil-to-sugar cane transfer of radionuclides occurred in the following order 40K>226Ra>232Th. Therefore, under these conditions, radionuclides intake through consumption of sugar is not hazardous to human health.

  5. Comment on `Update of 40K and 226Ra and 232Th series $\\gamma$-to-dose conversion factors for soil'

    CERN Document Server

    Malins, Alex; Saito, Kimiaki

    2015-01-01

    A letter to the editor of the Journal of Environmental Radioactivity on the article: E. Gasser, A. Nachab, A. Nourreddine, Ch. Roy, and A. Sellam, `Update of 40K and 226Ra and 232Th series $\\gamma$-to-dose conversion factors for soil', J. Environ. Radioactiv. 138, 68-71 (2014), DOI: 10.1016/j.jenvrad.2014.08.002.

  6. Statistical model calculations of pre-scission neutron multiplicity for the heavy ion induced fusion-fission reactions with actinide target 232Th

    Directory of Open Access Journals (Sweden)

    Thakur Meenu

    2015-01-01

    Full Text Available The reaction mechanism of 19F + 232Th and 28Si + 232Th systems populating the near-super-heavy compound nuclei 251Es and 260Rf respectively are investigated using neutron multiplicity as a probe. The prescission neutron multiplicities of these compound nuclei are calculated at different excitation energies using a statistical model code. These calculations are performed using the Bohr-Wheeler transition state fission width as well as the dissipative dynamical fission width based on the Kramers’ prescription. For 19F + 232Th system, the measured yield of pre-scission is compared with the statistical model calculations for the decay of a compound nucleus in the excitation energy range of 54-90 MeV. The comparison between the measured and the calculated values indicates that the Bohr-Wheeler fission width underestimates the pre-scission neutron yield and a large amount of dissipation strength is required to reproduce the experimental pre-scission neutron multiplicities. The excitation energy dependence of the fitted values of the dissipation coefficient is also discussed. In addition, exploratory statistical model calculations of pre-scission neutron multiplicity for the 28Si + 232Th system are presented in the above range of excitation energy.

  7. Verification tests on nondestructive assay for 238U content in uranium-contaminated waste drums using gamma method

    International Nuclear Information System (INIS)

    We have proposed a new theory on gamma assay for 238U determination of uranium-contaminated waste drums. According to this theory, regardless of the inhomogeneity of waste matrix density or uranium source distribution, we can accurately determine the amount of 238U contained in drums nondestructively using count rates of gamma rays of two energies(1001keV and 766keV) emitted from 238U progeny nuclide 234mPa. In this paper, we have verified the theory by tests under various waste conditions made by simulated waste drums. We have estimated the relative error to be less than 20%, and the detection limit to be 1.2Bq/g when the specific activity of uranium is 25000Bq/g, in these cases. We have confirmed that this new assay system is efficient for the rational classification of uranium wastes to be disposed of. (author)

  8. Production of $^{237}$U in the $^{238}$U ($\\gamma, n$) photonuclear reaction at the electron accelerator MT-25 microtron

    CERN Document Server

    Sabelnikov, A V; Gustova, M V; Belov, A G; Dmitriev, S N

    2004-01-01

    $^{237}$U was obtained in the $^{238}$U($\\gamma, n$) reaction at the electron accelerator MT-25 microtron of the FLNR of the JINR. The $^{237}$U radiation yield under experimental conditions amounted to 1 kBq/$\\mu $A$\\cdot $h$\\cdot$mg $^{238}$U. Capture of recoil atoms in a solid-solid system was used for isolation of $^{237}$U from the target material. Fluorides of chemical elements from I-III series of the Periodic Table of the Elements were used as $^{237}$U acceptors. The $^{237}$U isolation from radioactive impurities was realized by means of extraction and ion exchange. Specific activity of the $^{237}$U preparation was equal to 49500 kBq/mg $^{238}$U. The radioactive impurity content did not exceed 10$^{-6}$ Bq/Bq. The $^{237}$U chemical yield amounted to 70{\\%}.

  9. 238U, 234U, 226Ra, 210Po concentrations of bottled mineral waters in Italy and their dose contribution

    International Nuclear Information System (INIS)

    Due to the importance of bottled mineral water in human diet with special regard to children in lactation period, a monitoring of natural radioactivity in some bottled mineral waters produced in Italy was performed. Gross alpha and beta activities and 226Ra, 238U, 234U, and 210Po concentrations were measured. Gross alpha and beta activities were determined by standards ISO 9696 and ISO 9697; for 226Ra determination liquid scintillation was used. The 238U and 234U concentrations were determined by alpha spectrometry after their separation from matrix by extraction chromatography and electroplating. 210Po was measured by alpha spectrometry. The results revealed that the concentrations (mBq L-1) of 226Ra, 238U, 234U, and 210Po ranged from -1; for infants (-1

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

    International Nuclear Information System (INIS)

    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 235U/238U atom ratios in uranium samples. This consisted of evaluating the precision and accuracy on the 235U/238U 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 235U/238U atom ratios close to those of natural uranium ( i.e. 0.00730). (author)

  11. 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.

  12. Tests of the 238U+n evaluation for JEF-2 in the unresolved resonance region

    International Nuclear Information System (INIS)

    During the JEF-2 test phase the new evaluation for 238U+n in the unresolved resonance region (adopted for JEF-2 up to 200 keV, for ENDF/B-VI up to 149 keV) has been checked against recent capture cross section measurements and against thick-sample transmission data and capture self-indication ratios. Effects of the unresolved resonance structure on self-shielding and multiple scattering were treated by Monte Carlo techniques based on resonance statistics and average resonance parameters. It was found that the average cross sections and the average resonance parameters given in the new evaluation permit very satisfactory reproduction of all the test data. The resonance-averaged capture cross sections below 200 keV appear now to be known with roughly 2% uncertainty. (orig.)

  13. Charge-stripping system for 238U ion beam with recirculating He gas

    International Nuclear Information System (INIS)

    Recent developments in a charge-stripping system employing high-flow rate He gas circulation (∼200 L/min) for 238U35+ beams injected at 10.8 MeV/u are reported. He gas is confined in a target section and is separated from a vacuum duct using five-stage differentially-pumped sections. To minimize the gas leakage rate via beam apertures, a high-performance differential pumping was required. To avoid huge gas consumption, a clean gas recycling with high-flow rate was simultaneously required. To realize these, we developed multi-stage mechanical booster pump array. The recycling rate of He gas was achieved as more than 99 %. The system performance has been checked with the present maximum beam current up to 13 eμA (∼1 kW beam power). (author)

  14. Measurement of capture cross sections of 238U on the filtered keV-neutron beams

    International Nuclear Information System (INIS)

    Capture cross sections for the 238U(n,γ) reaction were measured related to that of the 197Au(n,γ) reaction on the filtered keV-neutron beams at the Dalat reactor using the activation method. Radioactivities of samples after irradiation were measured with HPGe detectors (50 mm2 sensitive area, FWHM = 150 eV for 55Fe and 70 cc volume, FWHM = 2.5 keV at 1332 keV γ-transition of 60Co). The data obtained by the authors were compared with the evaluations in ENDF/B-VI and JEF-2 and also with the results from recent experimental works. (author). 12 refs, 1 fig., 4 tabs

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

    Science.gov (United States)

    Nicholas, T; Bingham, D

    2011-03-01

    Radiation workers at Atomic Weapons Establishment (AWE) are monitored for uranium exposure by routine bioassay sampling (primarily urine sampling). However, the interpretation of uranium in urine and faecal results in terms of occupational intakes is difficult because of the presence of uranium due to intakes from environmental (dietary) sources. For uranium in urine data obtained using current analytical techniques at AWE, the mean, median and standard deviation of excreted uranium concentrations were 0.006, 0.002 and 0.012 μg per g creatinine, respectively. These values are consistent with what might be expected from local dietary intakes and the knowledge that occupational exposures at AWE are likely to be very low. However, some samples do exceed derived investigation levels (DILs), which have been set up taking account of the likely contribution from environmental sources. We investigate how the activity and isotopic composition of uranium in the diet affects the sensitivity of uranium in urine monitoring for occupational exposures. We conclude that DILs based on both total uranium in urine activity and also (234)U:(238)U ratios are useful given the likely variation in dietary contribution for AWE workers. Assuming a background excretion rate and that the enrichment of the likely exposure is known, it is possible to assess exposures using (234)U:(238)U ratios and/or total uranium activity. The health implications of internalised uranium, enriched to <5-8 % by mass (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. PMID:21036806

  16. Fluxes of 238U decay series radionuclides in a dicalcium phosphate industrial plant.

    Science.gov (United States)

    Casacuberta, N; Masqué, P; Garcia-Orellana, J

    2011-06-15

    The production of dicalcium phosphate (DCP) is part of the phosphate industry, which has been recently included in the positive list of the NORM industries defined in the revised version of the EU-BSS (Euratom 29/96). The objective of the present work is to study specific concentrations and fluxes of (238,234)U, (230)Th, (226)Ra, (210)Pb and (210)Po at the different stages of the DCP production. Results showed highest activities of (238)U and (210)Pb were found in DCP (1500-2000 Bq kg(-1)); (230)Th and (210)Po were released together with the sludges (1600-2000 Bq kg(-1)) and (226)Ra presented particularly high activities in water (48 × 10(3) Bq m(-3)) and in the reactor scales (115 × 10(3) Bq kg(-1)). Fluxes of radionuclides showed that (238)U outflows were equally distributed between sludges (16 × 10(3) kBq h(-1)) and dicalcium phosphate (20 × 10(3) kBq h(-1)); (230)Th and (210)Po were almost entirely released in the sludges (30 × 10(3)kBq h(-1)) and the greatest (210)Pb outflow was the DCP current (25 × 10(3) kBq h(-1)). (226)Ra was mainly discharged through the water effluent (12 × 10(3) kBq h(-1)). This work highlights the importance of studying the industrial processes involving NORM, as minor changes in the production steps lead to different radionuclide distribution in the process.

  17. Fluxes of {sup 238}U decay series radionuclides in a dicalcium phosphate industrial plant

    Energy Technology Data Exchange (ETDEWEB)

    Casacuberta, N., E-mail: Nuria.Casacuberta@uab.es [Institut de Ciencia i Tecnologia Ambientals - Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Masque, P.; Garcia-Orellana, J. [Institut de Ciencia i Tecnologia Ambientals - Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain)

    2011-06-15

    The production of dicalcium phosphate (DCP) is part of the phosphate industry, which has been recently included in the positive list of the NORM industries defined in the revised version of the EU-BSS (Euratom 29/96). The objective of the present work is to study specific concentrations and fluxes of {sup 238,234}U, {sup 230}Th, {sup 226}Ra, {sup 210}Pb and {sup 210}Po at the different stages of the DCP production. Results showed highest activities of {sup 238}U and {sup 210}Pb were found in DCP (1500-2000 Bq kg{sup -1}); {sup 230}Th and {sup 210}Po were released together with the sludges (1600-2000 Bq kg{sup -1}) and {sup 226}Ra presented particularly high activities in water (48 x 10{sup 3} Bq m{sup -3}) and in the reactor scales (115 x 10{sup 3} Bq kg{sup -1}). Fluxes of radionuclides showed that {sup 238}U outflows were equally distributed between sludges (16 x 10{sup 3} kBq h{sup -1}) and dicalcium phosphate (20 x 10{sup 3} kBq h{sup -1}); {sup 230}Th and {sup 210}Po were almost entirely released in the sludges (30 x 10{sup 3} kBq h{sup -1}) and the greatest {sup 210}Pb outflow was the DCP current (25 x 10{sup 3} kBq h{sup -1}). {sup 226}Ra was mainly discharged through the water effluent (12 x 10{sup 3} kBq h{sup -1}). This work highlights the importance of studying the industrial processes involving NORM, as minor changes in the production steps lead to different radionuclide distribution in the process.

  18. 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.

  19. Application of Energy Window Concept in Doppler Broadening of 238U Cross Section

    International Nuclear Information System (INIS)

    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 238U 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 238U 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

  20. 238U/235U determinations of some commonly used reference materials and U-bearing accessory minerals (Invited)

    Science.gov (United States)

    Condon, D.; Noble, S.; McLean, N.; Bowring, S. A.

    2009-12-01

    We have determined 238U/235U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials in addition to several U-bearing accessory phases (zircon and monazite) by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 233U-236U double spike to accurately correct for mass fractionation. The 238U/235U values for the natural uranium reference materials differ, by up to 0.1%, from the widely used ‘consensus’ value (137.88) with all having 238U/235U values less than 137.88. Similarly, initial 238U/235U data from zircon and monazite yield 238U/235U values that are lower than the ‘consensus’ value. The data obtained from U-bearing minerals is used to assess how the uncertainty in the 238U/235U ratio contributes to the systematic discordance observed in 238U/206Pb and 235U/207Pb dates (Mattinson, 2000; Schoene et al., 2006) which has traditionally been wholly attributed to error in the U decay constants. The 238U/235U determinations made on the synthetic reference materials yield results that are considerably more precise and accurate than the certified values (0.02% vs. 0.1% for CRM U500). The calibration of isotopic tracers used for U-daughter geochronology that are partially based upon these reference materials, and the resultant age determinations, will benefit from increased accuracy and precision. Mattinson, J.M., 2000. Revising the “gold standard”—the uranium decay constants of Jaffey et al., 1971. Eos Trans. AGU, Spring Meet. Suppl., Abstract V61A-02. Schoene B., Crowley J.L., Condon D.C., Schmitz M.D., Bowring S.A., 2006, Reassessing the uranium decay constants for geochronology using ID-TIMS U-Pb data. Geochimica et Cosmochimica Acta 70: 426-445

  1. Neutron Capture Cross Sections and Gamma Emission Spectra from Neutron Capture on 234,236,238U Measured with DANCE

    Science.gov (United States)

    Ullmann, J. L.; Mosby, S.; Bredeweg, T. A.; Couture, A. J.; Haight, R. C.; Jandel, M.; Kawano, T.; O'Donnell, J. M.; Rundberg, R. S.; Vieira, D. J.; Wilhelmy, J. B.; Wu, C.-Y.; Becker, J. A.; Chyzh, A.; Baramsai, B.; Mitchell, G. E.; Krticka, M.

    2014-05-01

    A new measurement of the 238U(n, γ) cross section using a thin 48 mg/cm2 target was made using the DANCE detector at LANSCE over the energy range from 10 eV to 500 keV. The results confirm earlier measurements. Measurements of the gamma-ray emission spectra were also made for 238U(n, γ) as well as 234,236U(n, γ). These measurements help to constrain the radiative strength function used in the cross-section calculations.

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

    International Nuclear Information System (INIS)

    The production of heavy nuclides from the spallation-evaporation reaction of 238U 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 208Pb and 197Au reveals the strong influence of fission in the spallation of 238U. (orig.)

  3. The applicability of MGA method for depleted and natural uranium isotopic analysis in the presence of actinides ({sup 232}Th, {sup 237}Np, {sup 233}Pa and {sup 241}Am)

    Energy Technology Data Exchange (ETDEWEB)

    Yuecel, Haluk [TAEK-Saraykoey Nuclear Research and Training Center, Atom Cad. No.27, Saray Mah, 06983 Ankara (Turkey)], E-mail: haluk.yucel@taek.gov.tr

    2007-11-15

    The multi-group analysis (MGA) method for the determination of uranium isotopic abundances in depleted uranium (DU) and natural uranium (NU) samples is applied in this study. A set of non-destructive {gamma}-ray measurements of DU and NU samples were performed using a planar Ge detector. The relative abundances of {sup 235}U and {sup 238}U isotopes were compared with the declared values of the standards. The relative abundance for {sup 235}U obtained by MGA for a 'clean' DU or NU sample with a content of uranium >1 wt% is determined with an accuracy of about {+-}5%. However, when several actinides such as {sup 232}Th, {sup 237}Np, {sup 233}Pa and {sup 241}Am are present along with uranium isotopes simulating 'dirty' DU or NU, it has been observed that MGA method gives erroneous results. The {sup 235}U abundance results for the samples were 6-25 times higher than the declared values in the presence of above-mentioned actinides, since MGA is utilized the X-ray and {gamma}-ray peaks in the 80-130 keV energy region, covering XK{sub {alpha}} and XK{sub {beta}} regions. After the least-squares fitting of the spectra, it is found that the increases in the intensities of the X-ray and {gamma}-ray peaks of uranium are remarkably larger in the complex 80-130 keV region. On the other hand, it is observed that the interferences of the actinide peaks are relatively less dominant in the higher {gamma}-ray region of 130-300 keV. The results imply the need for dirty DU and NU samples that the MGA method should utilize the higher energy {gamma}-rays (up to 1001 keV of {sup 234m}Pa) combined with lower energies of the spectra, which may be collected in a two detector mode (a planar Ge and a high efficient coaxial Ge)

  4. Combined 238U/235U and Pb Isotopics of Planetary Core Material: The Absolute Age of the IVA Iron Muonionalusta

    Science.gov (United States)

    Brennecka, G. A.; Amelin, Y.; Kleine, T.

    2016-08-01

    We report a measured 238U/235U for the IVA iron Muonionalusta. This measured value requires an age correction of ~7 Myr to the previously published Pb-Pb age. This has major implications for our understanding of planetary core formation and cooling.

  5. Vertical flux of particulate organic carbon in the central South China Sea estimated from 234Th-238U disequilibria

    Institute of Scientific and Technical Information of China (English)

    MA Hao; ZENG Zhi; HE Jianhua; CHEN Liqi; YIN Mingduan; ZENG Shi; ZENG Wenyi

    2008-01-01

    234Th-238u disequilibria were applied to examine the particle dynamics in the euphotic zone of the central South China Sea during the spring 2002 cruise. The particulate organic carbon (POC), 234Th (including both dissolved and particulate) and 238U in the water column at three stations were determined. The profiles of 234Th/238U activity ratio at the three stations all showed consistent 234Th deficit as compared to 238U in the upper 100 m water column. Based on the profiles of the dissolved and particulate 234Th and a steady state box model, the dissolved 234Th scavenging rates, the particulate 234Th removal rates and their resident times were quantified. It was found that the POC downward export fluxes out of the upper 100 m euphotic zone ranged from 9.40 to 14.78 mmol.m-2.d-1. The results from this study provide new information for our understanding of carbon biogeochemical cycle in the South China Sea.

  6. Field analyses of 238U and 226Ra in two uranium mill tailings piles from Niger using portable HPGe detector

    International Nuclear Information System (INIS)

    The radioactivities of 238U and 226Ra in mill tailings from the U mines of COMINAK and SOMAÏR in Niger were measured and quantified using a portable High-Purity Germanium (HPGe) detector. The 238U and 226Ra activities were measured under field conditions on drilling cores with 600s measurements and without any sample preparation. Field results were compared with those obtained by Inductive Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and emanometry techniques. This comparison indicates that gamma-ray absorption by such geological samples does not cause significant deviations. This work shows the feasibility of using portable HPGe detector in the field as a preliminary method to observe variations of radionuclides concentration with the aim of identifying samples of interest. The HPGe is particularly useful for samples with strong secular disequilibrium such as mill tailings. - Highlights: • A portable HPGe was used in the field to quantify 238U and 226Ra in mill tailings. • 238U and 226Ra quantification was performed on samples with strong radioactive disequilibrium. • HPGe measurements are compared with results obtained on the same samples by ICP-AES and emanometry. • We show the vertical distributions of U and 226Ra measured in two ∼30 m mill tailings piles. • Portable HPGe can be used directly in the field to observe slight variations of content

  7. Distribution Characteristics of Radionuclides in Soils Around Tailings Dump Sites of a Uranium Mining Field in South China%南方某铀尾矿区周边农田土壤中放射性核素的分布特征

    Institute of Scientific and Technical Information of China (English)

    姚高扬; 华恩祥; 高柏; 汪勇; 占凌之; 蒋经乾

    2015-01-01

    Uranium mining and beneficiation produces large amounts of tailings, which have become the main sources of radioactive contamination in the soil surrounding the tailings dump sites, directly or indirectly affecting human health. An investigation was performed of the soils around a uranium tailings dump site of a uranium mining field in South China, to explore distribution characteristics of radionuclides ( 238 U,226 Ra,232 Th and 40 K ) in paddy soil. Results show that the content of 238 U peaked at 40 cm in depth of a soil profile at Sampling Site No. 2, and the highest content of 238 U, 226 Ra, 232 Th and 40 K was found in the topsoil at all the other sampling sites. Moreover, within the 0-100 cm soil layer, the con-tents of radionuclides declined with soil depth gradually and the declining trend was the most obvious in the topsoil layer. The uneven distribution of radionuclides in the soil might be attributed to a variety of factors, such as human disturbance, local precipitation, soil pH, soil particle size, and horizontal distance from the dump site. Comprehensive evaluation of the radionuclides (238U, 226Ra, 232Th and 40K) in the paddy soil around the dump site was performed using the method of Nemerow′s pollution index ( NPI) as against the background values of the radionuclides in the soil of Jiangxi Province, in-dicating that the radioactive contamination in the paddy soil surrounding the uranium tailings dump site is at the hazardous level with NPI reaching 53. 45.%选取南方某铀尾矿库区周边土壤为研究对象,研究稻田土壤中放射性核素( 238 U、226 Ra、232 Th和40 K)的分布特征. 结果表明,2号点位238 U含量在土壤40 cm深处达到最大值,其余各采样点238 U、226 Ra、232 Th和40 K含量均在土壤表层达最高. 土壤0~1m深范围内,随深度增加放射性核素含量呈递减趋势,且在表层土壤下降速率更大.土壤中放射性核素含量分布不均匀可能受人为因素、当地降水量、

  8. Natural Isotopic Fractionation of 238U/235U in the Water Column of the Black Sea

    Science.gov (United States)

    Romaniello, S. J.; Brennecka, G.; Anbar, A. D.; Colman, A. S.

    2009-12-01

    The natural fractionation of long-lived uranium isotopes (238U, 235U) is being explored as a paleoredox proxy. While uranium behaves conservatively in oxic seawater, it is readily removed to sediments under reducing conditions. Measurements of δ238/235U in black shales and marine sediments deposited under sulfidic conditions suggest that uranium removed in such environments is isotopically heavy. However, this fractionation process has not been directly demonstrated in a present-day marine environment, nor is the specific mechanism of fractionation known. The euxinic water column of the Black Sea provides an ideal laboratory for studying uranium isotope fractionation. Uranium in Black Sea sediments is 0.35-0.84‰ heavy in δ238/235U relative to open ocean seawater (Weyer et al. 2008). We therefore expect that dissolved uranium in the Black Sea water column should be correspondingly light. Furthermore, direct measurements of δ238/235U versus depth could be used in combination with sediment δ238/235U to infer the dominant locations of U removal and constrain specific mechanisms of fractionation. Here we present the first δ238/235U depth profile from the water column of the Black Sea. The measurements were made on a Neptune MC-ICP-MS, using a 236U-233U double spike to correct for instrumental mass bias, following preconcentration and purification with UTEVA resin. With this method, we are able to measure δ238/235U with a 2σ precision of 0.07‰ on 100 ng samples. Our results show that δ238/235U decreases monotonically with depth (Fig. 1). At the surface, δ238/235U values are similar to those in the open ocean. At 2000m, δ238/235U is 0.28‰ lighter than open ocean seawater, while uranium concentrations are depleted by ~44% relative to conservative mixing. As expected, δ238/235U in the water column is always lighter than the underlying sediments, confirming that 238U is preferentially removed to marine sediments under sulfidic conditions. Fig 1. (left) Depth

  9. 238U(n, γ reaction cross section measurement with C6D6 detectors at the n_TOF CERN facility.

    Directory of Open Access Journals (Sweden)

    Mingrone F.

    2014-03-01

    Full Text Available The radiative capture cross section of 238U is very important for the developing of new reactor technologies and the safety of existing ones. Here the preliminary results of the 238U(n,γ cross section measurement performed at n_TOF with C6D6 scintillation detectors are presented, paying particular attention to data reduction and background subtraction.

  10. Distribution of 226 Ra, 232 Th, 40 K and 137 Cs in soils of Province of Camaguey, Cuba

    International Nuclear Information System (INIS)

    A survey programme aimed at studying the environmental radioactivity in the Province of Camaguey in the eastern region of Cuba was undertaken. The average concentrations of 226 Ra, 232 Th, and 40 K in the surveyed soils were 26.4, 11.5 and 210 Bq.kg-1, respectively. The man-made radionuclide found was 137 Cs and its concentration was similar to those reported in regions affected only by global radioactive fallout, (7.9 Bq.kg-1). Radiological measurements carried out with a portable ionization chamber RSS-112 at the sampled sites revealed an average outdoor absorbed dose rate of 59.0 nGy.h-1 due to cosmic rays and terrestrial gamma radiation. Computed dose rates obtained through the UNSCEAR(1993) dose coefficients range from 4-182 nGy.h-1, with a mean value of 27.8 nGy.h-1, due to natural terrestrial gamma radiation. Ratio of Indoor to Outdoor absorbed dose rates in air was 1.75. The average value of absorbed dose rate in air for the ionizing component of cosmic rays was 31.8 nGy.h-1 at sea level. Because of the 95% of the Camaguey population lives at altitudes close to sea level (10-100 m), the absorbed dose rate in outdoor air from ionizing component of cosmic rays was estimated to be 32.3 nGy.h-1. An annual average effective dose equivalent of 510 μSv was estimated for Camaguey population due to the ionizing component of cosmic and gamma terrestrial radiation. This value is lower than the 760 μSv.year-1 estimated as a world average by UNSCEAR (1993). (author)

  11. Structure of 4He and 4Li and decay of the giant resonances in 238U

    International Nuclear Information System (INIS)

    With the p(α, 3He p)n reaction it has been succeeded for the first time to produce 4Li really. The total cross section of this reaction could be described consistently regarding the sequential decay of states in the α particle, in 4Li, and the p-n final-state interaction for all measured spectra. For the excitation of the low-lying L=1 1- and 2- states in the α(p, p')α and the α(p, n)4Li reaction cross sections were extracted. These values are consistent with predictions from DWBA calculations for a one-particle transition from the s into the p shell. The found values for the resonance energies and the widths for the 2- ground state and the first excited 1- state of 4Li amount to Er = 3.4 MeV, γ2 = 1.0 MeV respectively Er = 5.7 MeV, γ2=1.5 MeV. With the coincident measurement of the 238U(α, α'f) reaction the decay of the giant quadrupole resonance was detected in the fission channel. (orig./HSI)

  12. Evaluation of correlating factors between {sup 238}U concentration measured in fine and course atmospheric particles

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, Claudia Marques; Jacomino, Vanusa Maria Feliciano; Barreto, Alberto Avelar; Dias, Vagner Silva, E-mail: cmp@cdtn.b, E-mail: vmfj@cdtn.b, E-mail: aab@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Dias, Fabiana Ferrari, E-mail: fdias@cnen.gov.b [Brazilian Nuclear Energy Commission (CNEN-/MG), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas (LAPOC)

    2009-07-01

    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 mum 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{sub 10}), defined as those particles with less than 10 mum 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{sub 10}, PI{sub 2.5} and PI{sub 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 {sup 238}U activity concentration results. (author)

  13. Determination of {sup 228}Th, {sup 232}Th, and{sup 228}Ra in wild mushroom from a naturally high radioactive region in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Mychelle M.L.; Taddei, Maria Helena T.; Silva, Marco A.; Ferreira, Marcelo T., E-mail: mychelle@cnen.gov.b, E-mail: mhtaddei@cnen.gov.b, E-mail: masilva@cnen.gov.b, E-mail: ferreira@cnen.gov.b [Brazilian Nuclear Energy Commission (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Lab. of Pocos de Caldas; Maihara, Vera A., E-mail: vmaihara@ipen.gov.b [Nuclear and Energy Research Institute (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Mushrooms are fungi which efficiently accumulate radionuclides, as verified by radiochemistry analyses of specimens collected in contaminated areas, specifically after the Chernobyl nuclear accident. Many studies have demonstrated that mushrooms can be used in monitoring of ecosystem contamination and quality. The present paper is part of a broader study conducted in the Pocos de Caldas plateau region in Minas Gerais, Brazil, investigating assimilation of natural Uranium and Thorium radionuclide series by mushrooms. This region has elevated natural radioactivity due to the presence of radiological anomalies of volcanic origin. These anomalies are ore bodies containing Uranium and Thorium, the later being highly predominant. Many researchers have been conducted concerning radionuclide incorporation by agricultural products on the plateau. The present paper aims to determine {sup 232}Th, {sup 228}Th, and {sup 228}Ra radionuclides in wild mushrooms collected at different locations in the plateau region. {sup 228}Ra was determined by radiochemical separation using sulphate coprecipitation followed by beta radiometry. {sup 232}Th and {sup 228}Th were determined using anion exchange resin purification followed by alpha spectrometry. Higher values were obtained to {sup 228}Th than to {sup 232}Th. This is due to higher {sup 228}Ra mobility, which decays to {sup 228}Th. The accuracy of the analytical methods employed was evaluated using the reference sample IAEA Soil 327. These methods had high chemical recovery and high sensitivity. It was possible to confirm that mushrooms accumulate radionuclide and so can be used in environmental contamination and quality assessment. (author)

  14. A preliminary study on 226Ra, 232Th, 40K and 137Cs activity concentrations in vegetables and fruits frequently consumed by inhabitants of Elazig Region, Turkey

    International Nuclear Information System (INIS)

    Determining radioactivity levels in foodstuffs is of great importance for the protection of human health. In addition, the literature includes few studies related to this subject in Turkey. In this study, gamma spectroscopic system was used in order to measure 226Ra, 232Th, 40K and 137Cs activity concentrations in vegetables and fruits produced in Elazig( Region. The average activity concentrations in vegetables was calculated as 0.64 ± 0.26 Bq kg-1 for 226Ra, 0.65 ± 0.14 Bq kg-1 for 232Th, 13.98 ± 1.22 Bq kg-1 for 40K, and 0.54 ± 0.04 Bq kg-1 for 137Cs. The average activity concentrations in fruits were 1.52 ± 0.34, 0.98 ± 0.23, 18.66 ± 1.13 and 0.59 ± 0.16 Bq kg-1, respectively for 226Ra, 232Th, 40K and 137Cs. Total committed effective dose value was determined as 20 and 30.55 μSv y-1, respectively for vegetables and fruits. The findings were compared with previous data reported for Turkey and other regions of the world. (author)

  15. Production of unknown neutron-rich isotopes in 238U collisions at near-barrier energy

    Science.gov (United States)

    Zhao, Kai; Li, Zhuxia; Zhang, Yingxun; Wang, Ning; Li, Qingfeng; Shen, Caiwan; Wang, Yongjia; Wu, Xizhen

    2016-08-01

    The production cross sections for primary and residual fragments with charge number from Z =70 to 120 produced in the collision of 238U at 7.0 MeV/nucleon are calculated by the improved quantum molecular dynamics (ImQMD) model incorporated with the statistical evaporation model (hivap code). The calculation results predict that about 60 unknown neutron-rich isotopes from elements Ra (Z =88 ) to Db (Z =105 ) can be produced with the production cross sections above the lower bound of 10-8 mb in this reaction. And almost all of the unknown neutron-rich isotopes are emitted at the laboratory angles θlab≤60°. Two cases, i.e., the production of the unknown uranium isotopes with A ≥244 and that of rutherfordium with A ≥269 , are investigated to understand the production mechanism of unknown neutron-rich isotopes. It is found that for the former case the collision time between two uranium nuclei is shorter and the primary fragments producing the residues have smaller excitation energies of ≤30 MeV and the outgoing angles of those residues cover a range of 30°-60°. For the latter case, a longer collision time is needed for a large number of nucleons being transferred and thus it results in higher excitation energies and smaller outgoing angles of primary fragments, and eventually results in a very small production cross section for the residues of Rf with A ≥269 which have a small interval of outgoing angles of θlab=40°-50°.

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

    International Nuclear Information System (INIS)

    This thesis describes a measurement of the heavy-ion induced electromagnetic dissociation of a 120 MeV/A 238U beam incident on five targets: 9Be, 27Al, natCu, natAg, and natU. 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

  17. Time-dependent Hartree-Fock calculations for multinucleon transfer and quasifission processes in $^{64}$Ni+$^{238}$U reaction

    CERN Document Server

    Sekizawa, Kazuyuki

    2016-01-01

    Background: Multinucleon transfer (MNT) and quasifission (QF) processes are dominant processes in low-energy collisions of two heavy nuclei. They are expected to be useful to produce neutron-rich unstable nuclei. Nuclear dynamics leading to these processes depends sensitively on nuclear properties such as deformation and shell structure. Purpose: We elucidate reaction mechanisms of MNT and QF processes involving heavy deformed nuclei, making detailed comparisons between microscopic TDHF calculations and measurements for $^{64}$Ni+$^{238}$U reaction. Methods: Three-dimensional Skyrme-TDHF calculations are performed. Particle-number projection method is used to evaluate MNT cross sections from the TDHF wave function after collision. Results: Fragment masses, total kinetic energy (TKE), scattering angle, contact time, and MNT cross sections are investigated for $^{64}$Ni+$^{238}$U reaction. They show reasonable agreements with measurements. At small impact parameters, collision dynamics depends sensitively on th...

  18. Measurement and analysis of the 238U(n, 2n) reaction rate in depleted uranium/polyethylene shells

    Institute of Scientific and Technical Information of China (English)

    YAN Xiao-Song; LIU Rong; LU Xin-Xin; JIANG Li; WEN Zhong-Wei; HAN Zi-Jie

    2012-01-01

    In order to check the conceptual design of the subcritical blanket in a fnsion-fission hybrid reactor,a depleted uranium/polyethylene simulation device with alternate shells has been established.The measurement of the 238U(n,2n) reaction rate was carried out using an activation technique,by measuring the 208 keV γ rays emitted from 237 U.The self-absorption of depleted uranium foils with different thicknesses was experimentally corrected.The distribution of the 238U(n,2n) reaction rate at 90° to the incident D+ beam was obtained,with uncertainty between 5.3% and 6.0%.The experiment was analyzed using MCNP5 code with the ENDF/BVI library,and the calculated results are all about 5% higher than the measured results.

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

    International Nuclear Information System (INIS)

    From 4 keV to 149 keV the 238U 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 238U 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

  20. Measurement and analysis of the 238U (n, 2n) reaction rate in depleted uranium/polyethylene shells

    International Nuclear Information System (INIS)

    In order to check the conceptual design of the subcritical blanket in a fusion-fission hybrid reactor, a depleted uranium/polyethylene simulation device with alternate shells has been established. The measurement of the 238U (n, 2n) reaction rate was carried out using an activation technique, by measuring the 208 keV γ rays emitted from 237U. The self-absorption of depleted uranium foils with different thicknesses was experimentally corrected. The distribution of the 238U (n, 2n) reaction rate at 90° to the incident D+ beam was obtained, with uncertainty between 5.3% and 6.0%. The experiment was analyzed using MCNP5 code with the ENDF/BVI library, and the calculated results are all about 5% higher than the measured results. (authors)

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

    International Nuclear Information System (INIS)

    The computer code SIOB has been used to obtain least-squares simultaneous-sample shape fits to the recent 238U 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 238U Discrepancy Task Force. 20 references

  2. Investigation of the {sup 236}U/{sup 238}U isotope abundance ratio in uranium ores and yellow cake samples

    Energy Technology Data Exchange (ETDEWEB)

    Srncik, M. [Vienna Univ. (Austria). Dept. of Inorganic Chemistry; European Commission, Joint Research Centre, Karlsruhe (Germany). Institute for Transuranium Elements; Mayer, K.; Hrnecek, E.; Wallenius, M.; Varga, Z. [European Commission, Joint Research Centre, Karlsruhe (Germany). Institute for Transuranium Elements; Steier, P. [Vienna Univ. (Austria). VERA Lab.; Wallner, G. [Vienna Univ. (Austria). Dept. of Inorganic Chemistry

    2011-07-01

    Uranium ores and yellow cake samples of known geographic origin were investigated for their n({sup 236}U)/n({sup 238}U) isotope abundance ratio. Samples from four different uranium mines in Australia, Brazil and Canada were selected. Uranium was separated by UTEVA {sup registered} Resin and was measured by Accelerator Mass Spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA). The measurement of the isotope abundance ratio n({sup 236}U)/n({sup 238}U) will be used to investigate possible correlations between the original mineral (uranium ore) and the intermediate product (yellow cake). Such correlations are useful indicators for nuclear forensic or for non-proliferation purposes. (orig.)

  3. Fission Fragment Angular Distribution measurements of 235U and 238U at CERN n_TOF facility

    Directory of Open Access Journals (Sweden)

    Leal-Cidoncha E.

    2016-01-01

    In order to measure the FFAD of neutron-induced reactions, a fission detection setup based on parallel-plate avalanche counters (PPACs has been developed and successfully used at the CERN-n_TOF facility. In this work, we present the preliminary results on the analysis of new 235U(n,f and 238U(n,f data in the extended energy range up to 200 MeV compared to the existing experimental data.

  4. Tectonic and radioactivity impacts of 238U on groundwater-based drinking water at Gosa and Lugbe areas of Abuja, North Central Nigeria

    International Nuclear Information System (INIS)

    Tectonic contribution of activity level of 238U in groundwater-based drinking water in Gosa and Lugbe areas of Abuja was measured using inductively coupled plasma mass spectrometry (ICP-MS). The highest activity level of 2736 µBq L-1 reported in Lugbe borehole, whereas the lowest value of 443 µBq L-1 reported at Gosa borehole. The inhabitants permanently used water from the boreholes for daily consumption. The group receives 5.55 × 10-5 mSv of the annual collective effective dose due to 238U in drinking water. The radiological risks of 238U in the water samples were found to be low, typically in magnitude of 10-7 with cancer mortality value of 1.03 × 10-7 and morbidity value of 1.57 × 10-7. The chemical toxicity risk of 238U in drinking water over a lifetime consumption has a mean value of 4.0 × 10-3 μg kg-1 day-1. It could be that the human risk due to 238U content in groundwater supplies from ingestion may likely be the chemical toxicity of 238U as a heavy metal rather than radiological risk. Significantly, Lugbe subsurface may have developed some fractions of granitic strata that contributed to the distribution of radioactive of 238U in tectonically weak zones. (author)

  5. 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.

  6. A dispersive optical model potential for nucleon induced reactions on 238U nucleus with 15 coupled levels

    International Nuclear Information System (INIS)

    A new dispersive coupled-channel optical model potential (OMP) for 238U nucleus is presented. The derived OMP couples almost all 238U excited levels below 1 MeV of excitation energy, including the ground state, octupole, beta, gamma, and non-axial bands. The coupled-channel potential is based on a vibrational-rotational description of the target nucleus structure, where dynamic vibrations are considered as perturbations of the rigid rotor underlying structure. OMP parameters that show a smooth energy dependence and energy independent geometry were determined from fits to the available experimental database (including strength functions and scattering radius) for neutron and proton scattering. The energy range 0.001-200 MeV is covered. Derived high-quality OMP is used to calculate the reaction cross section and corresponding theoretical uncertainties in nucleon-induced reactions on U-238. Theoretical calculations are compared with available results derived from existing experimental data on total cross-sections and angular distributions measurements based on the Wick's limit. Reduction of the uncertainty of the calculated reaction cross-section for neutron-induced reactions on 238U is discussed. (author)

  7. Theoretical modeling of traveling wave reactor fed with non-irradiated and pre-irradiated 238U fuels

    International Nuclear Information System (INIS)

    This paper deals with a traveling wave reactor theoretically. The breeding/burning wave is generated by a continuous radial fuel shuffling. Two-dimensional cylindrical core geometry is considered and the fuel is assumed to drift in the radial direction, which corresponds to a continuous radial fuel shuffling in practice. A one-group diffusion equation coupled with a burn-up solution is set up. The burn-up solution is obtained numerically, where the actinide inventories are simplified as functions of neutron fluence only. The uranium-plutonium (U-Pu) conversion cycle with pure 238U or 238U with its irradiation descendants as fresh fuel is considered under conditions of a typical sodium cooled fast reactor with uranium metallic fuel loaded. The asymptotic problems are solved by a time-stepping iteration scheme and the radial stationary wave solution is obtained together with certain eigenvalue keff. As a particular feature of this paper, the 238U pre-irradiated fuel is distributed with different irradiation doses along the axial axis. The purpose of this treatment is to remedy the power shape deformation in the uniform fresh fuel case. The results of both non-irradiated and pre-irradiated fuel, as examples for the inward fuel drifting motion, are compared and discussed. (author)

  8. Investigation of the 238U(d ,p ) surrogate reaction via the simultaneous measurement of γ -decay and fission probabilities

    Science.gov (United States)

    Ducasse, Q.; Jurado, B.; Aïche, M.; Marini, P.; Mathieu, L.; Görgen, A.; Guttormsen, M.; Larsen, A. C.; Tornyi, T.; Wilson, J. N.; Barreau, G.; Boutoux, G.; Czajkowski, S.; Giacoppo, F.; Gunsing, F.; Hagen, T. W.; Lebois, M.; Lei, J.; Méot, V.; Morillon, B.; Moro, A. M.; Renstrøm, T.; Roig, O.; Rose, S. J.; Sérot, O.; Siem, S.; Tsekhanovich, I.; Tveten, G. M.; Wiedeking, M.

    2016-08-01

    We investigated the 238U(d ,p ) reaction as a surrogate for the n +238U reaction. For this purpose we measured for the first time the γ -decay and fission probabilities of *239U simultaneously and compared them to the corresponding neutron-induced data. We present the details of the procedure to infer the decay probabilities, as well as a thorough uncertainty analysis, including parameter correlations. Calculations based on the continuum-discretized coupled-channels method and the distorted-wave Born approximation (DWBA) were used to correct our data from detected protons originating from elastic and inelastic deuteron breakup. In the region where fission and γ emission compete, the corrected fission probability is in agreement with neutron-induced data, whereas the γ -decay probability is much higher than the neutron-induced data. We have performed calculations of the decay probabilities with the statistical model and of the average angular momentum populated in the 238U(d ,p ) reaction with the DWBA to interpret these results.

  9. 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.

  10. Analysis of 226Ra, 232Th 40К and 137Cs in samples of soil from some areas of Republic of Macedonia by using gamma spectrometry

    Directory of Open Access Journals (Sweden)

    Todorovik Aleksandra

    2012-01-01

    Full Text Available Taking into consideration the importance of the distribution and transfer of radio nuclides in soil, an attempt was made in this work to determine the concentration of 226Ra, 232Th 40К and 137Cs in the same. The concentrations of activity in the gamma-absorbed dose rates of the terrestrial naturally occurring radio nuclides, as follows, 226Ra, 232Th and 40K were determined in samples of soil collected from some parts of Republic of Macedonia, i.e. from three major cities in the Republic of Macedonia. The samples are taken by means of a special dosage dispenser which enables sampling of samples at a depth of 0-5 cm, 5-10cm and 10-15cm, thus disabling the sampling above these layers of soil. An identification of radio nuclides and assessment of their activity has been performed by applying gamma spectrometry. The time of counting for each sample was 65000 s. in order to obtain statistically small mistake. The spectrums were analyzed by a commercially available software GENIE-2000 received from Canberra, Austria. The activity of soil had wide range of values: 20.3 to 82.9 Bq kg-1for 226Ra, 16.1 to 82.5 Bq kg-1 for 232Th, 325 to 799.0 Bq kg-1for 40К and 9.1 to 24.3 Bq kg-1for 137Cs, respectively. The concentrations of these radio nuclides have been compared with the available data from the other countries. Natural environmental radioactivity and the associated external exposure due to gamma radiation depend primarily on the geological and geographical conditions. Namely, the specific levels of terrestrial environmental radiation are related to the type of rocks from which the soils originate. The obtained data indicate that the average value of activity of 232Th is about higher than the one of 226Ra The concentration of activity of 40К in the soil has greater value than 32Th and 226Ra in all soils. The causes for the existence of 137Cs in these soils are the nuclear explosions, waste radioactive materials and other incidents. It reaches the

  11. Cost-based optimizations of power density and target-blanket modularity for {sup 232}Th/{sup 233}U-based ADEP

    Energy Technology Data Exchange (ETDEWEB)

    Krakowski, R.A.

    1995-07-01

    A cost-based parametric systems model is developed for an Accelerator-Driven Energy Production (ADEP) system based on a {sup 232}Th/{sup 233}U fuel cycle and a molten-salt (LiF/BeF{sub 2}/ThF{sub 3}) fluid-fuel primary system. Simplified neutron-balance, accelerator, reactor-core, chemical-processing, and balance-of-plant models are combined parametrically with a simplified costing model. The main focus of this model is to examine trade offs related to fission power density, reactor-core modularity, {sup 233}U breeding rate, and fission product transmutation capacity.

  12. Methods for the determination of 234U/230 U, 230Th/232 Th and 228Ra/226Ra in uranium ores by TIMS%TIMS测定铀矿石样品中234U/238U、230Th/232Th、228Ra/226Ra的方法研究

    Institute of Scientific and Technical Information of China (English)

    朱明燕; 郭冬发; 崔建勇; 刘宇昂; 谭靖; 张彦辉

    2009-01-01

    研究了TIMS测定铀矿石样品中234 U/238 U、230 Th/232 Th、228 Ra/226 Ra的方法.建立了铀矿石密闭混酸一次溶样的方法和采用阴离子、阳离子和Sr特效树脂逐级离子交换分离纯化U、Th和Ra的流程,满足了TIMS测量要求.测定结果表明:100~1000 ng的天然铀中234U/238U,其测量精密度从静态多接收的2.34%提高到动态多接收的0.47%;对230Th与232Th丰度接近、质量为1 μg左右的钍,采用三带点样技术和法拉第多接收技术测定230Th/232Th,其内精度平均值为0.0048%,外精度为0.028%;采用单带加钽发射剂,ETP跳峰测定50~100 fg镭-228稀释剂中的228Ra/226Ra,其内精度小于0.10%,外精度小于0.20%.比较TIMS和HR-ICP-MS、α能谱法测定234U/238U、230Th/232Th、228Ra/226Ra结果,三者结果相吻合.TIMS测量法样品用量少、快速、准确、精密度高,是U,Th、Ra同位素比值测定方法的又一补充.

  13. Estimation of radiation doses to member of the public in northern corridor of India from intake of naturally occurring radionuclide (238U) in drinking water

    International Nuclear Information System (INIS)

    In the present paper radiological quality in drinking water collected from northern corridor of India has been evaluated on the basis of 238U activity. Places considered under present study are distinctive for their geological point of view. Adsorptive stripping voltammetric (AdSV) technique has been used to estimate the total uranium content of water samples and then converted to 238U activity concentration using specific activity of 238U (12.356 mBq μg-1 of 238U) and used accordingly. The uranium concentration in water samples varies in a wide range from 0.15-251 μg L-1. These values are compared with safe limit values recommended for drinking water by WHO and USEPA. Most of the water samples are found to have uranium concentration below the safe limit of 30 μg L-1 (USEPA, 2003). Annual committed effective doses due to 238U was evaluated for the adult member of the public through the ingestion of the drinking water samples studied and compared with the reference level of the committed effective dose (100 μSv yr-1 recommended by the WHO. The dose due to 238U for all analysed samples of drinking water are in the range of 0.06-18.74 μSv yr-1 and found to be well below the reference level recommended by the WHO. (author)

  14. Estimation of dose contribution from 226Ra, 232Th and 40K radon exhalation rates in soil samples from Shivalik foot hills in India.

    Science.gov (United States)

    Chauhan, R P; Chauhan, Pooja; Pundir, Anil; Kamboj, Sunil; Bansal, Vakul; Saini, R S

    2014-01-01

    The concentration of radium, thorium and potassium and radon exhalation rates in soil samples collected from Shivalik foot hills in the states of Haryana and Himachal Pradesh (India) were experimentally measured. A high-resolution gamma-ray spectroscopic system was used for the measurement of natural radioactivity ((226)Ra, (232)Th and (40)K) at Inter-University Accelerator Center, New Delhi, using a coaxial n-type high-purity germanium detector (EG&G, ORTEC, Oak Ridge, USA). The mass exhalation rates (EM) of radon in soil samples from the study area measured by 'sealed canister technique' using LR-115 type II track detectors varied from 50±1 to 143±6 mBqkg(-1) h(-1). The activity concentrations of (226)Ra, (232)Th and (40)K in various soil samples of the study area varied from 31±1.3 to 63±4.6, 53±1.8 to 78±2.6 and 472±4.8 to 630±7.0 Bq kg(-1) respectively. The results indicated some higher levels of radioactivity in Lal Dhang peak area of the hills compared with other locations under study. PMID:23893776

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

    Energy Technology Data Exchange (ETDEWEB)

    Patin, Joshua B.

    2002-05-24

    The study of the reactions between heavy ions and {sup 208}Pb, {sup 209}Bi, {sup 238}U, and {sup 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 {sup 238}U({sup 18}O,xn){sup 256-x}Fm, {sup 238}U({sup 22}Ne,xn){sup 260-x}No, and {sup 248}Cm({sup 15}N,xn){sup 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 {sup 208}Pb({sup 48}Ca,xn){sup 256-x}No, {sup 208}Pb({sup 50}Ti,xn){sup 258-x}Rf, {sup 208}Pb({sup 51}V,xn){sup 259-x}Db, {sup 209}Bi({sup 50}Ti,xn){sup 259-x}Db, and {sup 209}Bi({sup 51}V,xn){sup 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.

  16. Multi-modal calculations of prompt fission neutrons from 238U(n, f) at low induced energy

    Institute of Scientific and Technical Information of China (English)

    ZHENG Na; ZHONG Chun-Lai; FAN Tie-Shuan

    2011-01-01

    Properties of prompt fission neutrons from 238U(n,f) are calculated for incident neutron energies below 6 MeV using the multi-modal model,including the prompt fission neutron spectrum,the average prompt fission neutron multiplicity,and the prompt fission neutron multiplicity as a function of the fission fragment mass v(A) (usually named “sawtooth” data) The three most dominant fission modes are taken into account.The model parameters are determined on the basis of experimental fission fragment data.The predicted results are in good agreement with the experimental data.

  17. Gamma Emission Spectra from Neutron Resonances in 234,236,238U Measured Using the Dance Detector at Lansce

    Science.gov (United States)

    Ullmann, J. L.; Bredeweg, T. A.; Couture, A. J.; Haight, R. C.; Jandel, M.; Kawano, T.; Keksis, A. L.; O'Donnell, J. M.; Rundberg, R. S.; Vieira, D. J.; Wouters, J. M.; Wilhelmy, J. B.; Wu, C. Y.; Becker, J. A.; Chyzh, A.; Baramsai, B.; Mitchell, G. E.; Krticka, M.

    2013-03-01

    An accurate knowledge of the radiative strength function and level density is needed to calculate of neutron-capture cross sections. An additional constraint on these quantities is provided by measurements of γ-ray emission spectra following capture. We present γ-emission spectra from several neutron resonances in 234,236,238U, measured using the DANCE detector at LANSCE. The measurements are compared to preliminary calculations of the cascade. It is observed that the generalized Lorentzian form of the E1 strength function cannot reproduce the shape of the emission spectra, but a better description is made by adding low-lying M1 Lorentzian strength.

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

    International Nuclear Information System (INIS)

    Essential oils were extracted from 35 medicinal plants used by Syrians, organic compounds were determined in these oils and concentrations of 210Po 210Pb and 238U were determined in the original plants and in the essential oils. The results showed that the highest activity concentrations of 210Po and 210Pb 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 238U was as high as 4.26 Bq kg−1 in Aloe. On the other hand, activity concentrations of 210Po ranged between 0.2 and 71.1 Bq kg−1 in extracted essential oils for Rosemary and False yellowhead, respectively. The activity concentration of 210Pb reached 63.7 Bq kg−1 in Aloe oil. The activity concentrations of 238U were very low in all extracted oils; the highest value was 0.31 Bq kg−1 in peel of Orange oil. The transfer of 210Po and 210Pb from plant to its oil was the highest for Eugenia; 7.1% and 5.5% for 210Po and 210Pb, 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 210Po, 210Pb and 238U were determined in 35 medicinal plants and their essential oils. • The highest activity concentration of 210Po and 210Pb were 73.5 Bq kg−1 and 73.2 Bq kg−1 in Sage, respectively. • The transfer of 210Po and 210Pb 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

  19. Fission Fragment Angular Distribution measurements of 235U and 238U at CERN n_TOF facility

    Science.gov (United States)

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

    2016-03-01

    Neutron-induced fission cross sections of 238U and 235U are used as standards in the fast neutron region up to 200 MeV. A high accuracy of the standards is relevant to experimentally determine other neutron reaction cross sections. Therefore, the detection effciency should be corrected by using the angular distribution of the fission fragments (FFAD), which are barely known above 20 MeV. In addition, the angular distribution of the fragments produced in the fission of highly excited and deformed nuclei is an important observable to investigate the nuclear fission process. In order to measure the FFAD of neutron-induced reactions, a fission detection setup based on parallel-plate avalanche counters (PPACs) has been developed and successfully used at the CERN-n_TOF facility. In this work, we present the preliminary results on the analysis of new 235U(n,f) and 238U(n,f) data in the extended energy range up to 200 MeV compared to the existing experimental data.

  20. Resolved-resonance neutron widths from a consistent reanalysis of the most recent 238U transmission data

    International Nuclear Information System (INIS)

    The 238U neutron differential capture cross sections are one of the most important nuclear data for reactor physics calculations. Nevertheless, differential data have persistently over-predicted the ratio of the 238U capture rate relative to the 239Pu fission rate in fast-reactor spectra as measured by integral experiments. One of the possible ways of perhaps reducing this discrepancy is to extend the theoretically sound resolved-resonance range upwards in energy from the present 4 to 10 keV. One of the major obstacles to such an extension is the published discrepancies among the resolved-resonance region neutron widths from 1 to 4 keV from the three most recent transmission measurements and analysis: the 1978 results of Olsen from Oak Ridge National Laboratory (ORNL); the 1975 results of Poortmans from the Central Bureau of Nuclear Measurements (CBNM) in Belgium; and the 1975 results of Nakajima from the Japan Atomic Energy Research Institute (JAERI). In this paper, the results of a detailed reanalysis of the three recent transmission measurements over three narrow energy regions are reported: region 1, 3820 to 4000 eV, six large resonances; region 2, 2470 to 2740 eV, ten large resonances; and region 3, 1460 to 1820 eV, twelve large resonances

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

    Energy Technology Data Exchange (ETDEWEB)

    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 /sup 230/Th was preferentially retained over either /sup 234/U or /sup 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 /sup 234/U and /sup 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 /sup 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 /sup 230/Th in ore dust is questioned.

  2. Trace metal cycling and 238U/235U in New Zealand's fjords: Implications for reconstructing global paleoredox conditions in organic-rich sediments

    Science.gov (United States)

    Hinojosa, Jessica L.; Stirling, Claudine H.; Reid, Malcolm R.; Moy, Christopher M.; Wilson, Gary S.

    2016-04-01

    Reconstructing the history of ocean oxygenation provides insight into links between ocean anoxia, biogeochemical cycles, and climate. Certain redox-sensitive elements respond to changes in marine oxygen content through phase shifts and concomitant isotopic fractionation, providing new diagnostic proxies of past ocean hypoxia. Here we explore the behavior and inter-dependence of a suite of commonly utilized redox-sensitive trace metals (U, Mo, Fe, and Mn) and the emerging "stable" isotope system of U (238U/235U, or δ238U) in New Zealand fjords. These semi-restricted basins have chemical conditions spanning the complete redox spectrum from fully oxygenated to suboxic to intermittently anoxic/euxinic. In the anoxic water column, U and Mo concentrations decrease, while Fe and Mn concentrations increase. Similarly, signals of past euxinic conditions can be found by U, Mo, Fe, and Mn enrichment in the underlying sediments. The expected U isotopic shift toward a lower δ238U in the anoxic water column due to U(VI)-U(IV) reduction is not observed; instead, water column δ238U profiles are consistent in fjords of all oxygen content, falling within previously reported ranges for open ocean seawater (δ238U = -0.42 ± 0.07‰). Additionally, surface sediment δ238U results show evidence for competing U isotope fractionation processes. One site indicates increased export of 238U from seawater to the underlying sediments (fractionation between aqueous seawater U and particulate sediment U, or ΔU(aq)-U(solid) = -0.25‰), consistent with redox-driven fractionation. Another site suggests potential U(VI) adsorption-driven fractionation, reflecting increased export of 235U from seawater to sediments (ΔU(aq)-U(solid) = 0.25‰). We discuss several potential factors that could alter δ238U in waters and sediments beyond redox-driven shifts, including adsorption to organic matter in waters of high primary productivity, reaction rates for competing processes of U adsorption and

  3. Redundant 230Th/ 234U/ 238U, 231Pa/ 235U and 14C dating of fossil corals for accurate radiocarbon age calibration

    Science.gov (United States)

    Chiu, Tzu-Chien; Fairbanks, Richard G.; Mortlock, Richard A.; Cao, Li; Fairbanks, Todd W.; Bloom, Arthur L.

    2006-09-01

    230Th/ 234U/ 238U dating of fossil corals by mass spectrometry is remarkably precise, but some samples exposed to freshwater over thousands of years may gain and/or lose uranium and/or thorium and consequently yield inaccurate ages. Although a δ 234U initial value equivalent to modern seawater and modern corals has been an effective quality control criterion, for samples exposed to freshwater but having δ 234U initial values indistinguishable from modern seawater and modern corals, there remains a need for additional age validation in the most demanding applications such as the 14C calibration (Fairbanks et al., 2005. Radiocarbon calibration curve spanning 0 to 50,000 years BP based on paired 230Th/ 234U/ 238U and 14C dates on pristine corals. Quaternary Science Reviews 24(16-17), 1781-1796). In this paper we enhance screening criteria for fossil corals older than 30,000 years BP in the Fairbanks0805 radiocarbon calibration data set (Fairbanks et al., 2005) by measuring redundant 230Th/ 234U/ 238U and 231Pa/ 235U dates via multi-collector magnetic sector inductively coupled plasma mass spectrometry (MC-MS-ICPMS) using techniques described in Mortlock et al. (2005. 230Th/ 234U/ 238U and 231Pa/ 235U ages from a single fossil coral fragment by multi-collector magnetic-sector inductively coupled plasma mass spectrometry. Geochimica et Cosmochimica Acta 69(3), 649-657.). In our present study, we regard paired 231Pa/ 235U and 230Th/ 234U/ 238U ages concordant when the 231Pa/ 235U age (±2 σ) overlaps with the associated 230Th/ 234U/ 238U age (±2 σ). Out of a representative set of 11 Fairbanks0805 (Fairbanks et al., 2005) radiocarbon calibration coral samples re-measured in this study, nine passed this rigorous check on the accuracy of their 230Th/ 234U/ 238U ages. The concordancy observed between 230Th/ 234U/ 238U and 231Pa/ 235U dates provides convincing evidence to support closed system behavior of these fossil corals and validation of their 230Th/ 234U/ 238U

  4. Towards A Modern Calibration Of The 238U/235U Paleoredox Proxy: Apparent Uranium Isotope Fractionation Factor During U(VI)-U(IV) Reduction In The Black Sea

    Science.gov (United States)

    Rolison, J. M.; Stirling, C. H.; Middag, R.; Rijkenberg, M. J. A.; De Baar, H. J. W.

    2015-12-01

    The isotopic compositions of redox-sensitive metals, including uranium (U), in marine sediments have recently emerged as powerful diagnostic tracers of the redox state of the ancient ocean-atmosphere system. Interpretation of sedimentary isotopic information requires a thorough understating of the environmental controls on isotopic fractionation in modern anoxic environments before being applied to the paleo-record. In this study, the relationship between ocean anoxia and the isotopic fractionation of U was investigated in the water column and sediments of the Black Sea. The Black Sea is the world's largest anoxic basin and significant removal of U from the water column and high U accumulation rates in modern underlying sediments have been documented. Removal of U from the water column occurs during the redox transition of soluble U(VI) to relatively insoluble U(IV). The primary results of this study are two-fold. First, significant 238U/235U fractionation was observed in the water column of the Black Sea, suggesting the reduction of U induces 238U/235U fractionation with the preferential removal of 238U from the aqueous phase. Second, the 238U/235U of underlying sediments is related to the water column through the isotope fractionation factor of the reduction reaction but is influenced by mass transport processes. These results provide important constraints on the use of 238U/235U as a proxy of the redox state of ancient oceans.

  5. Mass asymmetry dependence of fusion time-scales in 11B+237Np and 12C, 16O, 19F+232Th reactions in a dynamical trajectory model

    International Nuclear Information System (INIS)

    Dynamical trajectory calculations were carried out for the reactions of 11B+237Np and 12C, 16O and 19F+232Th, having mass asymmetries on either side of the Businaro-Gallone critical mass asymmetry αBG, in order to examine the mass asymmetry dependence of fusion reactions in these systems. The compound nucleus formation times were calculated as a function of the partial wave of the reaction for all the systems. This study brings out that for systems with αBG, the formation times are significantly larger than for α>αBG, which is caused by the dynamical effects involved in the large scale shape changes taking place in the fusion process as well as due to the interplay between the thermal and the collective motion during the collision process. The calculated time scales are comparable to the experimental values derived from the pre-fission neutron multiplicity measurements. (author). 16 refs., 4 figs., 1 tab

  6. Spectroscopy study after quasi-elastic collision in the system 208Pb+232Th at an incident energy of 17 MeV per nucleon

    International Nuclear Information System (INIS)

    In the present thesis by means of a particle-particle-γ and particle-particle-neutron coincidence experiment γ and neutron spectroscopic studies after quasi-elastic collisions at incident energies far above the Coulomb barrier were performed. For the study of the γ decay by the necessary correction of the Doppler shift the possibility results to study excitations in the projectile and in the target. So in the case of 232Th beside the observation of the ground state band up to the spin 14 ℎ also a very large number of transitions from vibrational side bands. From the spectra the γ emission probabilities in dependence on the distance of closest approximation were extracted. (orig./HSI)

  7. Determination of Fission Product Yields of 235U, 238U and 239Pu for Neutron Energies from 0.5 to 14.8 MeV

    Science.gov (United States)

    Gooden, Matthew; Arnold, Charles; Becker, John; Bhatia, Chitra; Bhike, Megha; Fowler, Malcolm; Howell, Calvin; Kelley, John; Stoyer, Mark; Tonchev, Anton; Tornow, Werner; Vieira, Dave; Wilhelmy, Jerry

    2014-03-01

    A joint TUNL-LANL-LLNL collaboration has been formed to study the issue of possible energy dependences for certain fission product isotopes. Work has been carried out at the TUNL 10 MV Tandem accelerator which produces nearly mono-energetic neutrons via either 2H(d,n)3He,3H(d,n)4He,or3H(p,n)3He reactions. Three dual fission ionization chambers dedicated to 235U, 238U and 239Pu thick target foils and thin monitor foils respectively, were exposed to the neutron beams. After irradiation, thick target foils were gamma counted over a period of 1-2 months and characteristic gamma rays from fission products were recorded using HPGe detectors at TUNL's low background counting area. Using the dual fission chambers, relative fission product yield were determined at a high precision of 2-3 % as well as absolute fission product yields at a lower precision of 5-6 %. Preliminary results will be presented for a number of fission product isotopes over the incident neutron energy range of 0.5 to 14.8 MeV.

  8. Study of secondary neutron interactions with 232 Th, 129 I, and 127 I nuclei with the uranium assembly " QUINTA " at 2, 4, and 8 GeV deuteron beams of the JINR Nuclotron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Adam, J. [ASCR, Prague; Chilap, V. V. [IPTP, Dubna; Furman, M. G. [Dubna, JINR; Khushvaktov, J. [Dubna, JINR; Pronskikh, V. S. [Fermilab; Solnyshkin, A. A.. [Dubna, JINR; Stegailov, V. I. [Dubna, JINR; Suchopar, M. [ASCR, Prague; Tsoupko-Sitnikov, V. M. [Dubna, JINR; Tyutyunnikov, S. I. [Dubna, JINR; Vrzalova, J.. [Dubna, JINR; Wagner, V. [ASCR, Prague; Zavorka, L. [Dubna, JINR

    2016-06-01

    The natural uranium assembly, "QUINTA", was irradiated with 2, 4, and 8 GeV deuterons. The 232 Th, 127 I, and 129 I samples have been exposed to secondary neutrons produced in the assembly at a 20-cm radial distance from the deuteron beam axis. The spectra of gamma rays emitted by the activated 232 Th, 127 I, and 129 I samples have been analyzed and several tens of product nuclei have been identified. For each of those products, neutron-induced reaction rates have been determined. The transmutation power for the 129 I samples is estimated. Experimental results were compared to those calculated with well-known stochastic and deterministic codes.

  9. Finite Range Effects on Fusion and/or Breakup of 6He+238U and 11Li+208Pb Systems

    Institute of Scientific and Technical Information of China (English)

    Sukhvinder S. Duhan; Manjeet Singh; Rajesh Kharab; H.C. Sharma

    2011-01-01

    We have studied the effects of the finite range of the interaction between the fragments of the projectile on the fusion and/or breakup of 6He+238U and 11 Li+208 Pb systems at near barrier energies within the framework of dynamic polarization potential approach.It has been found that at near barrier energies the maximum flux is lost to the breakup channel and at energies well above the Coulomb barrier the fusion coupled with the breakup channel opens up, initially with sharp rise and later becoming saturated at energy nearly twice of the Coulomb barrier.Further, it is found that the breakup cross section increases with the increasing range of the interaction between the fragments of the projectile while the fusion coupled with the breakup channel cross section decreases with the increasing range.

  10. Production of new superheavy Z=108-114 nuclei with $^{238}$U, $^{244}$Pu and $^{248,250}$Cm targets

    CERN Document Server

    Feng, Zhao-Qing; Li, Jun-Qing

    2009-01-01

    Within the framework of the dinuclear system (DNS) model, production cross sections of new superheavy nuclei with charged numbers Z=108-114 are analyzed systematically. Possible combinations based on the actinide nuclides $^{238}$U, $^{244}$Pu and $^{248,250}$Cm with the optimal excitation energies and evaporation channels are pointed out to synthesize new isotopes which lie between the nuclides produced in the cold fusion and the $^{48}$Ca induced fusion reactions experimentally, which are feasible to be constructed experimentally. It is found that the production cross sections of superheavy nuclei decrease drastically with the charged numbers of compound nuclei. Larger mass asymmetries of the entrance channels enhance the cross sections in 2n-5n channels.

  11. Polonium 210Po, uranium (234U, 238U and plutonium (238Pu, 239+240Pu bioaccumulation in marine birds

    Directory of Open Access Journals (Sweden)

    Strumińska-Parulska D. I.

    2013-04-01

    Full Text Available The aim of this work was the determination of 210Po, 234U, 238U, 238Pu and 239+240Pu concentration in marine birds which permanently or temporally live in the southern Baltic Sea coast. We chose 11 species of seabirds: three species permanently residing at southern Baltic Sea, four species of wintering birds and three species of migrating birds. The results show that analyzed radionuclides are non-uniformly distributed in the marine birds. The highest activities of 210Po were observed in feathers, muscles and liver. The highest uranium content was found in liver, rest of viscera and feathers, while plutonium in the digestion organs and feathers. Omnivore seabirds accumulated more polonium, plutonium than species that feed on fish, while herbivore seabirds accumulated more uranium than carnivore.

  12. 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.

  13. 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.

  14. Coupling groundwater residence time and 234U/238U isotopic ratios in a granitic catchment (Vosges, Eastern France)

    Science.gov (United States)

    Viville, Daniel; Aquilina, Luc; Ackerer, Julien; Chatton, Eliot; Labasque, Thierry; Pierret, Marie-Claire; Granet, Mathieu; Perrone, Thierry; Chabaux, François

    2016-04-01

    Weathering processes are active in surface waters but groundwater also represents no neglectable chemical fluxes. As residence-time in groundwater are high, silicate weathering might take place and control Si, Ca and C fluxes. Weathering processes can be deduced from U isotopic ratios but the kinetics of these processes remain relatively poorly constrained. In order to better characterize these processes, we have coupled residence-times deduced from anthropogenic gases (CFC and SF6) analysis and 234U/238U isotopic ratios determination. Samples were collected in the Strengbach catchment (Hydro-geochemical Observatory OHGE, Vosges, eastern France). Two campaigns were carried out in May and August 2015 during two highly contrasted hydro-climatic periods. Both springs and boreholes down to 80 m depth have been sampled. A very clear geochemical distinction is observed between groundwater from surface springs and deeper groundwater from boreholes. Springs show much lower residence-time (few years) and specific chemical composition. Deeper groundwater have residence-time of several decades and different geochemical composition. A clear SF6 production is observed with increasing SF6 concentrations with residence-time. The campaign of May is characterized by highly groundwater levels and spring fluxes. All groundwater show very low residence time, except in the boreholes at depth greater than 40 m. Conversely, during low groundwater-level period in August, the residence times are much higher and CFC concentrations indicate a large mixing process between surface groundwater and deeper levels. The 234U/238U isotopic ratios confirm this vertical zonation in the boreholes, with much higher activity ratios in the deep ground-waters from borehole than in the surface and spring waters; Such high U activity ratios are indicative of long water-rock interactions, which is consistent with the long residence times deducted from the CFC and SF6 data.

  15. The transfer of uranium isotopes 234U and 238U to the waters interacting with carbonates from Mendip Hills area (England)

    International Nuclear Information System (INIS)

    Laboratory time-scale experiments were conducted on limestone and dolomite gravels from the Mendip Hills area, England, with the purpose of evaluating the release of 238U and 234U to different aqueous solutions. The 234U/238U activity ratio (AR) lab data were reliable to interpret the field data. The obtained values do not indicate a reduction in the amount of dissolved U and an increase in the AR of the remaining dissolved U as commonly observed for groundwater systems close to redox boundaries

  16. Assessment of sedimentation rate based on disequilibrium in the {sup 232}Th decay series in an artificial pond downstream a former uranium mine

    Energy Technology Data Exchange (ETDEWEB)

    Reyss, J.L. [Laboratoire des Sciences du Climat et de l' Environnement - LSCE/IPSL, Unite Mixte de Recherche 8212 CEA, CNRS, UVSQ, F-91198 Gif-sur-Yvette Cedex (France); Mangeret, A.; Courbet, C.; Saadi, Z.; Guillevic, J. [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP 17, 92262 Fontenay aux Roses (France); Thouvenot, A. [LMGE, UMR CNRS 6023, Lab Microorganismes Genome et Environnement, 63 177 Aubiere (France)

    2014-07-01

    In rivers and lakes, sediment dynamics are very difficult to quantify by field measurements as well as by modeling studies (Olley et al. 1997 WRR 33, 1319-1326). The well-known {sup 210}Pb excess method (Appleby 2000 Limnology 59-S.1, 1-14; Perga et al. 2010 Limnol. and Ocean. 55, 803-816) cannot be used for quantifying sedimentation rates over granitic catchments as large amounts of {sup 210}Pb produced by granite weathering tend to dilute the atmospheric {sup 210}Pb. The knowledge of sedimentation rates in lakes is however very important for understanding the geochemical mechanisms involved in contaminant scavenging and remobilization at the sediment-water interface (SWI). Moreover, these measurements are crucial for developing solute transport models, especially for radionuclides and metals in pore waters and through the SWI. In order to overcome these issues, this study focuses on an artificial pound located in a granitic catchment, down-gradient from a former uranium mining site that ceased operations at the beginning of the 80's (Guillevic and Reyss 2011 ICRER 2011). Sediment sampling was carried out in this artificial lake with an UWITEC{sup R} hand corer. All the samples were dried and the activities of artificial and natural radionuclides were measured by gamma spectrometry, at the Underground Laboratory of Modane and alpha spectrometry after radiochemical purification. The profile of {sup 210}Pb activities in the sediment increased with depth in the core and did not allow to distinguish the atmospheric {sup 210}Pb from the {sup 210}Pb produced by watering processes in this uranium enriched environment. Another method for quantifying sediment accumulation rates is therefore proposed here using the disequilibrium between {sup 228}Ra (half-life of 5.75 years) and {sup 232}Th, the parent isotope. The excess of {sup 228}Ra over its respective parent {sup 232}Th has already been demonstrated by (Olley et al. 1997 WRR 33, 1319-1326) in river and lake

  17. 234U/238U isotope data from groundwater and solid-phase leachate samples near Tuba City Open Dump, Tuba City, Arizona

    Science.gov (United States)

    Johnson, Raymond H.; Horton, Robert J.; Otton, James K.; Ketterer, Michael K.

    2012-01-01

    This report releases 234U/238U isotope data, expressed as activity ratios, and uranium concentration data from analyses completed at Northern Arizona University for groundwater and solid-phase leachate samples that were collected in and around Tuba City Open Dump, Tuba City, Arizona, in 2008.

  18. Measurement of 238U muonic x-rays with a germanium detector setup

    Energy Technology Data Exchange (ETDEWEB)

    Esch, Ernst I [Los Alamos National Laboratory; Jason, Andrew [Los Alamos National Laboratory; Miyadera, Haruo [Los Alamos National Laboratory; Hoteling, Nathan J [Los Alamos National Laboratory; Heffner, Robert H [Los Alamos National Laboratory; Adelmann, Andreas [PAUL SCHERRER INSTITUT; Stocki, Trevor [HEALTH CANADA; Mitchell, Lee [NAVAL RESEARCH LAB

    2009-01-01

    In the field of nuclear non-proliferation muon interactions with materials are of great interest. This paper describes an experiment conducted at the Paul Scherrer Institut (PSI) in Switzerland where a muon beam is stopped in a uranium target. The muons produce characteristic muonic x-rays. Muons will penetrate shielding easily and the produced characteristic x-rays can be used for positive isotope identification. Furthermore, the x-rays for uranium isotopes lie in the energy range of 6-7 MeV, which allows them to have an almost optimal mean free path in heavy shielding such as lead or steel. A measurement was conducted at PSI to prove the feasibility of detecting muonic x-rays from a large sample of depleted uranium (several kilograms) with a germanium detector. In this paper, the experimental setup and analysis of the measurement itself is presented.

  19. First 236U data from the Arctic Ocean and use of 236U/238U and 129I/236U as a new dual tracer

    Science.gov (United States)

    Casacuberta, N.; Masqué, P.; Henderson, G.; Rutgers van-der-Loeff, M.; Bauch, D.; Vockenhuber, C.; Daraoui, A.; Walther, C.; Synal, H.-A.; Christl, M.

    2016-04-01

    The first dataset of 236U/238U in the water column of the Arctic Ocean (AO) is presented and shows the widest range of ratios reported so far in the open ocean, from (5 ± 5) to (3840 ± 260) ×10-12. Surface samples and depth profiles were collected during two GEOTRACES expeditions in 2011-2012 and analyzed for the concentrations of 236U and 129I, with the aim of investigating whether the combination of 236U/238U and 129I/236U can be used as a new oceanographic tool in the AO. Results show that the distributions of the 236U/238U and 129I/236U atomic ratios are consistent with the different water masses in the AO. High 236U/238U and 129I/236U ratios in the upper water column (> 2000 ×10-12 and >200, respectively) illustrate the penetration of Atlantic waters (AW) into the AO. Lower values were found in Pacific waters (PW) and deep waters of the AO. Rivers seem to represent a temporally and spatially-constrained third anthropogenic source of 236U but more data are needed to confirm this. In a simple mixing model, the combination of 236U/238U and 129I/236U reveals a high contribution (>99%) of natural background waters (pre-nuclear era) in the deep and bottom waters of the Amerasian basin, indicating an apparent water mass renewal time of >1000 years. Despite the relatively high apparent age of the Amerasian Basin deep waters, this work shows the potential of using the dual-tracer approach as a new oceanographic tool in the Arctic Ocean.

  20. Neutronic simulation of a research reactor core of (232Th, 235U)O2 fuel using MCNPX2.6 code

    Indian Academy of Sciences (India)

    Seyed Amir Hossein Feghhi; Marzieh Rezazadeh; Yachine Kadi; Claudio Tenreiro; Morteza Aref; Zohreh Gholamzadeh

    2013-01-01

    The small reactor design for the remote and less developed areas of the user countries should have simple features in view of the lack of infra-structure and resources. Many researchers consider long core life with no on-site refuelling activity as a primary feature for the small reactor design. Long core life can be achieved by enhancing internal conversion rate of fertile to fissile materials. For that purpose, thorium cycle can be adopted because a high fissile production rate of 233U converted from 232Th can be expected in the thermal energy region. A simple nuclear reactor core arranged 19 assemblies in hexagonal structure, using thorium-based fuel and heavy water as coolant and moderator was simulated using MCNPX2.6 code, aiming an optimized critical assembly. Optimized reflector thickness and gap between assemblies were determined to achieve minimum neutron leakage and void reactivity. The result was a more compact core, where assemblies were designed having 19-fuel pins in 1.25 pitch-to-diameter ratio. Optimum reflector thickness of 15 cm resulted in minimal neutron leakage in view of economic limitations. A 0.5 cm gap between assembles achieved more safety and 2.2% enrichment requirements. The present feasibility study suggests a thermal core of acceptable neutronic parameters to achieve a simple and safe core.

  1. Search for mass-symmetric ternary fission in the reactions {sup 14}N(53 A MeV)+{sup 197}Au and {sup 232}Th

    Energy Technology Data Exchange (ETDEWEB)

    Herbach, C.-M. E-mail: herbach@hmi.de; Hilscher, D.; Tishchenko, V.G.; Gippner, P.; Kamanin, D.V.; Oertzen, W. von; Ortlepp, H.-G.; Penionzhkevich, Yu.E.; Pyatkov, Yu.V.; Renz, G.; Schilling, K.D.; Strekalovsky, O.V.; Wagner, W.; Zhuchko, V.E

    2002-12-30

    Ternary fission of heavy hot composite systems with excitation energies of 1.5-2.5 MeV/amu has been studied in the reactions of {sup 14}N(53 A MeV) with {sup 197}Au and {sup 232}Th. The ternary yields have been explored as a function of the charge Z{sub L} of the lightest fragment: while Z{sub L} increases from 6 to 25, the cross sections decrease from 5 to 0.08 mb for N+Au and from 15 to 0.8 mb for N+Th. The velocity vector v{yields}{sub L} of the lightest fragment has been investigated in the rest frame of the other two heavier fragments. Two different components are observed: (i) an isotropic one with values of v{sub L} corresponding to the Coulomb repulsion from the combined heavier fragments before separation and, (ii) an anisotropic contribution with the lightest fragment emitted with lower v{sub L} perpendicular to the scission axis of the two heavier fragments. The latter component is distinguished from the isotropic one by an enhanced fraction of mass-symmetric ternary events and by up to 50 MeV lower total kinetic fragment energies. These features are indicative of a collinear stretched scission configuration, where the lightest fragment is positioned between the two heavier ones.

  2. Concentration in activity of 137 Cs, 40 K, 232 Th, 226 Ra in waste deposits of the benefits of minerals in the State of Zacatecas

    International Nuclear Information System (INIS)

    The necessity to report the changes in the contained radionuclides in the terrestrial crust, or those deposited by the atomic tests around the world, becomes clear when observing the use of material of waste of those mines. With the purpose of quantifying the concentration in activity its were meet a series of waste samples in mines of the municipalities of Zacatecas, Fresnillo, Guadalupe and Veta Grande of the state of Zacatecas, Mexico. The analysis was carried out by gamma spectrometry with a HPGe detector with a resolution of 1.9 keV corresponding to an energy of 1.33 MeV calibrated in efficiency and energy by means of a certified standard multi nuclide in activity with identical geometry to that of the samples. The times of count are of 80000 seconds, with the purpose of to reduce the relative uncertainties and to define well the interest regions. The activity of 226 Ra and 232 Th is obtained through the one 214 Bi and 228 Ac respectively, the concentration was also measured in activity of the one 40 K and the 137 Cs in units of Bq kg-1. (Author)

  3. Calibration factors for determination of relativistic particle induced fission rates in natU, 235U, 232Th, natPb and 197Au foils

    International Nuclear Information System (INIS)

    Calibration factors w, for determination of fission rate in metallic foils of natU, 235U, 232Th, natPb and 197Au were determined for foils in contact with synthetic mica track detectors. Proton-induced fission at proton energies of 0.7 GeV and 1.5 GeV were used. Using our experimental results as well as those of the other authors, w for different foil-mica systems were determined. Two methods were used to calculate w, relative to the calibration factor for uranium-mica system, which has been obtained in a standard neutron field of energy 14.7 MeV. One of these methods requires the knowledge of the mean range of the fission fragments in the foils of interest and other method needs information on the values of the fission cross-sections at the required energies as well as the density of the tracks recorded in the track detectors in contact with the foil surfaces. The obtained w-values were compared with Monte Carlo calculations and good agreements were found. It is shown that a calibration factor obtained at low energy neutron induced fissions in uranium isotopes deviates only by less than 10% from those obtained at relativistic proton induced fissions.

  4. 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)

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

    International Nuclear Information System (INIS)

    Low-energy-capture gamma-ray spectra (238U up to a neutron energy of 350 eV. The data were obtained using a 25-cm3 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 239U 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)

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

    International Nuclear Information System (INIS)

    An investigation has been made of the statistical frequency function for the distances between the 238U and the 239Pu 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

  7. Gamma-Ray Emission Spectra as a Constraint on Calculations of 234 , 236 , 238U Neutron-Capture Cross Sections

    Science.gov (United States)

    Ullmann, J. L.; Krticka, M.; Kawano, T.; Bredeweg, T. A.; Baramsai, B.; Couture, A.; Haight, R. C.; Jandel, M.; Mosby, S.; O'Donnell, J. M.; Rundberg, R. S.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Wu, C. Y.; Chyzh, A.

    2015-10-01

    Calculations of the neutron-capture cross section at low neutron energies (10 eV through 100's of keV) are very sensitive to the nuclear level density and radiative strength function. These quantities are often poorly known, especially for radioactive targets, and actual measurements of the capture cross section are usually required. An additional constraint on the calculation of the capture cross section is provided by measurements of the cascade gamma spectrum following neutron capture. Recent measurements of 234 , 236 , 238U(n, γ) emission spectra made using the DANCE 4 π BaF2 array at the Los Alamos Neutron Science Center will be presented. Calculations of gamma-ray spectra made using the DICEBOX code and of the capture cross section made using the CoH3 code will also be presented. These techniques may be also useful for calculations of more unstable nuclides. This work was performed with the support of the U.S. Department of Energy, National Nuclear Security Administration by Los Alamos National Security, LLC (Contract DE-AC52-06NA25396) and Lawrence Livermore National Security, LLC (Contract DE-AC52-07NA2734).

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

    Science.gov (United States)

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

    2005-01-01

    Lichens are widely used to assess the atmospheric pollution by heavy metals and radionuclides. However, few studies are available in publications on using lichens to qualitatively assess the atmospheric pollution levels. The paper presents research results applying epiphytic lichens as bio-monitors of quantitative atmospheric contamination with uranium. The observations were conducted during 2.5 years in the natural environment. Two experimental sites were used: one in the vicinity of a uranium contamination source, the other one - at a sufficient distance away to represent the background conditions. Air and lichens were sampled at both sites monthly. Epiphytic lichens Hypogimnia physodes were used as bio-indicators. Lichen samples were taken from various trees at about 1.5m from the ground. Air was sampled with filters at sampling stations. The uranium content in lichen and air samples as well as isotopic mass ratios (235)U/(238)U were measured by mass-spectrometer technique after uranium pre-extraction. Measured content of uranium were 1.45 mgkg(-1) in lichen at 2.09 E-04 microgm(-3) in air and 0.106 mgkg(-1) in lichen at 1.13 E-05 microgm(-3) in air. The relationship of the uranium content in atmosphere and that in lichens was determined, C(AIR)=exp(1.1 x C(LICHEN)-12). The possibility of separate identification of natural and man-made uranium in lichens was demonstrated in principle. PMID:16083999

  9. 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...

  10. Activity ratios of (234)U/(238)U and (226)Ra/(228)Ra for transport mechanisms of elevated uranium in alluvial aquifers of groundwater in south-western (SW) Punjab, India.

    Science.gov (United States)

    Kumar, A; Karpe, R K; Rout, S; Gautam, Y P; Mishra, M K; Ravi, P M; Tripathi, R M

    2016-01-01

    The concentrations of total dissolved uranium (U), its isotopic composition ((234)U, (235)U, (238)U) and two long lived Ra isotopes ((226)Ra and (228)Ra) in alluvial aquifers of groundwater were determined to investigate the groundwater flow pattern in the south-western (SW) Punjab, India. Particular attention was given to the spatial variability of activity ratios (ARs) of (234)U/(238)U and (226)Ra/(228)Ra to predict the possible sources and supply process of U into the water from the solid phase. The measured groundwater (234)U/(238)U ARs were ∼1 or >1 in the shallow zone (depth  30 m) with relatively low U concentration. The simultaneous elevated U concentration and (234)U/(238)U ARs in waters were possibly due to differences in imprints of rock-water interactions under hydrologic conditions. However, (234)U/(238)U ARs uranium in the aquifers.

  11. 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

  12. 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

  13. Determination of the neutron capture cross sections of 232Th at 14.1 MeV and 14.8 MeV using the neutron activation method

    CERN Document Server

    Lan, Chang-Lin; Peng, Meng; Lv, Tao; Yao, Ze-en; Chen, Jin-Gen; Kong, Xiang-Zhong

    2016-01-01

    The 232Th(n,{\\gamma})233Th neutron capture reaction cross sections were measured at average neutron energies of 14.1 MeV and 14.8 MeV using the activation method. The neutron flux was determined using the monitor reaction 27Al(n,{\\alpha})24Na. The induced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. The experimentally determined cross sections were compared with the literatures data, evaluated data of ENDF/B-VII, JENDL-4.0, and CENDL-3.1. The Excitation functions of 232Th(n,{\\gamma}) reaction were also calculated theoretically using the TALYS 1.6 computer code.

  14. Distribution of {sup 226} Ra, {sup 232} Th, {sup 40} K and {sup 137} Cs in soils of Province of Camaguey, Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Osvaldo Brigido; Barreras Caballero, Aldo A.; Montalvan Estrada, Adelmo; Queipo Garcia, Maite [Ministerio da Ciencia, Tecnologia y Medio Ambiente, Camaguey (Cuba). Centro de Atencion a la Actividad Nuclear. Lab. de Vigilancia Radiologica Ambiental]. E-mail: sean@caonao.cmw.inf.cu; Zerquera, Juan Tomas [Centro de Proteccion y Higiene de las Radiaciones, La Habana (Cuba)

    2001-07-01

    A survey programme aimed at studying the environmental radioactivity in the Province of Camaguey in the eastern region of Cuba was undertaken. The average concentrations of {sup 226} Ra, {sup 232} Th, and {sup 40} K in the surveyed soils were 26.4, 11.5 and 210 Bq.kg{sup -1}, respectively. The man-made radionuclide found was {sup 137} Cs and its concentration was similar to those reported in regions affected only by global radioactive fallout, (7.9 Bq.kg{sup -1}). Radiological measurements carried out with a portable ionization chamber RSS-112 at the sampled sites revealed an average outdoor absorbed dose rate of 59.0 nGy.h{sup -1} due to cosmic rays and terrestrial gamma radiation. Computed dose rates obtained through the UNSCEAR(1993) dose coefficients range from 4-182 nGy.h{sup -1}, with a mean value of 27.8 nGy.h{sup -1}, due to natural terrestrial gamma radiation. Ratio of Indoor to Outdoor absorbed dose rates in air was 1.75. The average value of absorbed dose rate in air for the ionizing component of cosmic rays was 31.8 nGy.h{sup -1} at sea level. Because of the 95% of the Camaguey population lives at altitudes close to sea level (10-100 m), the absorbed dose rate in outdoor air from ionizing component of cosmic rays was estimated to be 32.3 nGy.h{sup -1}. An annual average effective dose equivalent of 510 {mu}Sv was estimated for Camaguey population due to the ionizing component of cosmic and gamma terrestrial radiation. This value is lower than the 760 {mu}Sv.year{sup -1} estimated as a world average by UNSCEAR (1993). (author)

  15. Recent capture cross-sections validation on 232Th from 0,1 eV to 40 keV and self-shielding effect evaluation

    International Nuclear Information System (INIS)

    Research on ADS, related new fuels and their ability for nuclear waste incineration leads to a revival of interest in nuclear cross-sections of many nuclides in a large energy range. Discrepancies observed between nuclear databases require new measurements in several cases. A complete measurement of such cross-sections including resonance resolution consists in an extensive beam time experiment associated to a long analysis. With a slowing down spectrometer associated to a pulsed neutron source, it is possible to determine a good cross-section profile in an energy range from 0.1 eV to 40 keV by making use of a slowing-down time lead spectrometer associated to a pulsed neutron source. These measurements performed at ISN (Grenoble) with the neutron source GENEPI requires only small quantities of matter (as small as 0.1 g) and about one day of beam by target. We present cross-section profile measurements and an experimental study of the self-shielding effect. A CeF3 scintillator coupled with a photomultiplier detects gamma rays from neutronic capture in the studied target. The neutron flux is also measured with a 233U fission detector and a 3He detector at symmetrical position to the PM in relation to the neutron source. Absolute flux values are given by activation of Au and W foils. The cross-section profiles can then be deduced from the target capture rate and are compared with very detailed MCNP simulations, which reproduce the experimental set-up and provide also capture rates and flux. The method is then applied to 232Th, of main interest for new fuel cycle studies, and is complementary to higher energy measurements made by D. Karamanis et al. (CENBG). Results obtained for three target thicknesses will be compared with simulations based on different data bases. Special attention will be paid to the region of unresolved resonances (>100 eV). (author)

  16. 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.

  17. Understanding and modeling of the vertical downward migration of 238U within the soil profile of south-western (SW) Punjab, India

    International Nuclear Information System (INIS)

    The vertical downward migration of 238U in soils collected from south-western Punjab was studied from the depth distributions using the diffusion-convection model. The time-dependent convective rates (ν) of 238U were found to be in the order of 10-7-10-4 cm year-1, whereas under the assumption of steady state (time-independent), values were in the order of 10-5-10-4 cm year-1. However, the diffusion rates (D) were in the order of 10-6-10-3 cm2 year-1 and under the steady state, values obtained to be relatively higher as 0.002-0.70 cm2 year-1. These values were within the range of reported literature values. (author)

  18. Study of the 238U(d,p) surrogate reaction via the simultaneous measurement of gamma-decay and fission probabilities

    CERN Document Server

    Ducasse, Q; Aïche, M; Marini, P; Mathieu, L; Görgen, A; Guttormsen, M; Larsen, A C; Tornyi, T; Wilson, J N; Barreau, G; Boutoux, G; Czajkowski, S; Giacoppo, F; Gunsing, F; Hagen, T W; Lebois, M; Lei, J; Méot, V; Morillon, B; Moro, A; Renstrøm, T; Roig, O; Rose, S J; Sérot, O; Siem, S; Tsekhanovich, I; Tveten, G M; Wiedeking, M

    2015-01-01

    We investigated the 238U(d,p) reaction as a surrogate for the n + 238U reaction. For this purpose we measured for the first time the gamma-decay and fission probabilities of 239U* simultaneously and compared them to the corresponding neutron-induced data. We present the details of the procedure to infer the decay probabilities, as well as a thorough uncertainty analysis, including parameter correlations. Calculations based on the continuum-discretized coupled-channels and distorted-wave Born approximations were used to correct our data from detected protons originating from elastic and inelastic deuteron breakup. The corrected fission probability is in agreement with neutron-induced data, whereas the gamma-decay probability is much higher than the neutron-induced data. The performed statistical-model calculations are not able to explain these results.

  19. Bioaccumulation of polonium (210Po, uranium (234U, 238U isotopes and trace metals in mosses from Sobieszewo Island, northern Poland

    Directory of Open Access Journals (Sweden)

    Boryło A.

    2013-04-01

    Full Text Available The objective of this study was determination of the polonium (210Po, uranium (234U and 238U radionuclides and trace metals (Pb, Fe, Zn, Cu, Ni, Cd, Hg concentrations in mosses samples from Sobieszewo Island near the phosphogypsum waste dump in Wiślinka (northern Poland. The obtained results revealed that the concentrations of 210Po, 234U, and 238U in the two analyzed kinds of mosses: Pleurozium schreberi and Dicranum scoparium were similar. Among the analyzed trace metals the highest concentration in mosses was recorded for iron, while the lowest for nickel, cadmium and mercury. The obtained studies showed that the sources of polonium and uranium isotopes, as well as trace metals in analyzed mosses are air city contaminations transported from Gdańsk and from existing in the vicinity the phosphogypsum waste heap in Wiślinka (near Gdańsk.

  20. Study of The Total Reaction Cross Section of 17.0 MeV=N 132 Xe + 238 U Heavy Ion Interactions

    OpenAIRE

    BALUCH, J.J.; Khan, E. U.

    1998-01-01

    We have studied heavy ion nuclear interactions of 17.0 MeV/N 132Xe+238U using muscovite mica as Solid State Nuclear Track Detector (SSNTD). Experimental reaction cross section has been determined by two independent methods. Theoretical reaction cross section has been calculated by a classical formula taking into account the energy dependence of the nuclear radius parameter. The cross section determined in the present work has been compared with those at two other energies for the same reaction.

  1. Evaluation of the extractive procedure for determination of 238U and 234U in groundwater and comparison with traditional α-spectrometry technique

    International Nuclear Information System (INIS)

    Photon/Electron Rejecting Alpha Liquid Scintillation (PERALS) spectrometry has been used for the determination of uranium radionuclides in the ground water samples. The technique utilizes a commercially available extractive scintillant URAEX, which is selective for uranium. The cocktail extracted uranium from aqueous medium quantitatively and the efficiency of extraction was nearly 100% with no self-absorption or geometry problems. This method applies to pulse-shape discrimination of PERALS counting spectrometry and completely separates the alpha activity from the beta/gamma background. The resolutions of the 238U, 234U and 232U obtained in this method were good enough to for measurement of uranium isotopes in a quantitative way. The lower limit of detection was found to be 2.0 mBq l-1 for 2 hours counting time for a sample volume of 200 ml. The levels of 238U and 234U concentrations in groundwater samples of several locations were found to range from 12.8 ± 1.0 to 148.3 ± 10.8 mBq l-1 and 16.1 ± 1.2 to 106.7 ± 8.2 mBq l-1, respectively. For the bottled drinking water samples collected from markets, the 238U and 234U concentrations were found to range from below detectable level (BDL) to 38.7 ± 2.4 mBq l-1 and 47.3 ± 2.8 mBq l-1, respectively. The results of uranium radionuclides (238U and 234U) in groundwater and bottled water samples measured by PERALS method were compared with that obtained by alpha spectrometric method. (author)

  2. Measurement of the energy deposition profile for 238U ions with specific energy 500 and 950 MeV/u in stainless steel and copper targets

    International Nuclear Information System (INIS)

    The paper presents the results of precision measurements of the total stopping range and energy deposition function of 238U ions with specific energies E = 500 and 950 MeV/u in stainless steel and copper targets. The experiment was performed at the SIS-18 facility (GSI Darmstadt) in the experimental area Cave A in September 2004-May 2005. The measured energy deposition profiles are compared with calculations using the codes ATIMA, PHITS, SHIELD and SRIM

  3. Determination of the 238U capture to total fission ratio in alternate depleted uranium/polyethylene shells with D-T neutrons

    International Nuclear Information System (INIS)

    Aiming at checking the conceptual design of the subcritical blanket in the fusion–fission hybrid reactor, an integral experiment was carried out on an alternate depleted uranium/polyethylene-shell setup with D-T neutrons using activation technique. 18 depleted uranium foils were placed at 90° direction to the incident D beam, and the distribution of the 238U capture to total fission ratio was determined by measuring the 277.6 keV γ ray generated by neutron capture of 238U and the 293.3 keV γ ray generated by fission of 235U and 238U. The ratios were generally between 1 and 2 in the depleted uranium shells, with relative uncertainties between 3.0% and 5.5%. The ratios were calculated by the MCNP4B code employing ENDF/B-VI nuclear data library, the discrepancies between calculations and experiments were all within 6%, and the average calculation to experiment(C/E) ratio was 0.998.

  4. Suitable gamma energy for gamma-spectrometric determination of (238)U in surface soil samples of a high rainfall area in India.

    Science.gov (United States)

    Lenka, P; Jha, S K; Gothankar, S; Tripathi, R M; Puranik, V D

    2009-06-01

    The paper presents a systematic study on suitability of various gamma lines for monitoring of (238)U activity in soil samples around a uranium mineralized zone of Kylleng Pyndengsohiong Mawthabah (Domiasiat), Meghalaya in India. The area lies in a plateau region which recieves the highest average annual rainfall (12,000mm) in the world. The geochemical behaviour of the uranium and its daughter products at such wet climatic conditions imposes restrictions to assess (238)U through gamma lines of radon decay products. Soil samples were collected from nine locations around the uranium mineralization zone for analysis. The ratio of the concentration of uranium obtained from gamma energies of radium daughter products to the 63.29keV of (234)Th was found to vary from 1.01 to 2.07, which indicates a pronounced disequilibrium between uranium and radium daughters. The results obtained from various gamma energies were validated from the data generated by Instrumental Neutron Activation Analysis (INAA) technique. The (238)U activities from the two analytical methods show a well fitted regression line with correlation coefficient 0.99 which validates the reliability of 63.29keV energy for estimation of uranium in such conditions. PMID:19375833

  5. 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)

    The concentrations of 238U and 226Ra 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 238U equal to 15.6 ± 2.6 mBq kg-1 and tea has the maximum concentration of 226Ra equal to 1153.3 ± 265.3 mBq kg-1. Besides, the maximum annual effective dose from 238U and 226Ra 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)

  6. Role of sediment characteristics on natural radiation level of the Vaigai river sediment, Tamilnadu, India

    International Nuclear Information System (INIS)

    The sediment characteristics such as granulometric contents (sand, silt and clay), organic matter, magnetic susceptibility (low and high frequency) and weight percentage of magnetic minerals and the natural radionuclide (238U, 232Th and 40K) contents have been analyzed for the sediment samples of Vaigai river with an aim of evaluating the radiation hazard nature and assessing characterization of sediment. Granulometric analysis confirmed that the sand is major content. The organic matter content is ranged from 0.30 to 8.62% and comparison shows that the present river has high organic content. The magnetic measurement results indicated that the sites S16, S18 and S25 may be affected anthropogenically. Frequency dependence magnetic susceptibility is calculated to know the contribution of grains to magnetic susceptibility. Average of activity concentrations (except 40K) and all calculated radiological parameters are within the recommended level. Multivariate statistical analyses (Pearson correlation, cluster and factor analysis) dictated that the role of sediment characteristics on the level of radioactivity in the river sediments. The content of organic matter and clay, and magnetic parameters are positively correlated with important radioactive variables. The measurement of organic matter and magnetic susceptibility in various granulometric contents show some higher values in silt and clay fractions. Radioactivity level was also measured for the samples (after removing silt and clay fractions from bulk samples) and the results show decrease in radioactive variables. The present study stated that the lower grain sized fractions have the ability to absorb the contents such as organic content and magnetic minerals as cations on their surface and raise the level of radioactivity. Percentage of decrease in the natural radionuclides of 238U, 232Th, 40K and absorbed dose rate of the samples (after removing the silt and clay fractions from bulk samples) to the bulk samples

  7. 210Pb- 226Ra and 228Ra- 232Th systematics in young arc lavas: implications for magma degassing and ascent rates

    Science.gov (United States)

    Turner, Simon; Black, Stuart; Berlo, Kim

    2004-10-01

    New data show that island arc rocks have ( 210Pb/ 226Ra) o ratios which range from as low as 0.24 up to 2.88. In contrast, ( 228Ra/ 232Th) appears always within error of 1 suggesting that the large 226Ra-excesses observed in arc rocks were generated more than 30 years ago. This places a maximum estimate on melt ascent velocities of around 4000 m/year and provides further confidence that the 226Ra excesses reflect deep (source) processes rather than shallow level alteration or seawater contamination. Conversely, partial melting must have occurred more than 30 years prior to eruption. The 210Pb deficits are most readily explained by protracted magma degassing. Using published numerical models, the data suggest that degassing occurred continuously for periods up to several decades just prior to eruption but no link with eruption periodicity was found. Longer periods are required if degassing is discontinuous, less than 100% efficient or if magma is recharged or stored after degassing. The long durations suggest much of this degassing occurs at depth with implications for the formation of hydrothermal and copper-porphyry systems. A suite of lavas erupted in 1985-1986 from Sangeang Api volcano in the Sunda arc are characterised by deficits of 210Pb relative to 226Ra from which 6-8 years of continuous 222Rn degassing would be inferred from recent numerical models. These data also form a linear ( 210Pb)/Pb-( 226Ra)/Pb array which might be interpreted as a 71-year isochron. However, the array passes through the origin suggesting displacement downwards from the equiline in response to degassing and so the slope of the array is inferred not to have any age significance. Simple modelling shows that the range of ( 226Ra)/Pb ratios requires thousands of years to develop consistent with differentiation occurring in response to cooling at the base of the crust. Thus, degassing post-dated, and was not responsible for magma differentiation. The formation, migration and extraction

  8. {sup 226}Ra, {sup 232}Th and {sup 40}K contents and radon exhalation rate from materials used for construction and decoration in Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Ngachin, M; Njock, M G Kwato [Center for Atomic, Molecular Physics and Quantum Optics, University of Douala, PO Box 8580, Douala (Cameroon); Garavaglia, M; Giovani, C; Scruzzi, E [Regional Agency for Environmental Protection (ARPA), 91 via Tavagnacco, 33100 Udine (Italy); Nourreddine, A [Institut Pluridisciplinaire Hubert-Curien, UMR7178 CNRS-IN2P3 and Universite Louis Pasteur, 23 rue de Loess, BP 28, F-67037, Strasbourg cedex 02 (France); Lagos, L [Applied Research Center, Florida International University, 10555 W Flagler Street, EC 2100, Miami, FL 33174 (United States)], E-mail: mngachin@yahoo.com

    2008-09-01

    This work deals with the measurement of radioactivity and radon exhalation rate from building materials manufactured in Douala city from geological materials. Nine types of building material were surveyed for their natural radioactivity contents using high-resolution gamma-ray spectrometry. The activity concentrations for {sup 226}Ra, {sup 232}Th and {sup 40}K varied from 11.5 to 49 Bq kg{sup -1}, 16 to 37 Bq kg{sup -1} and 306 to 774 Bq kg{sup -1}, respectively. The absorbed dose rate in the samples investigated at 1 m above ground level ranged from 28.5 to 66.6 nGy h{sup -1}. External and internal hazard indices were also estimated as defined by the European Commission. The Ra equivalents of the materials studied ranged from 57.5 to 133 Bq kg{sup -1} and are much smaller than the recommended limit of 370 Bq kg{sup -1} for construction materials for dwellings. Polycarbonate nuclear track detectors (NTDs), type CR-39, were used for measuring the radon concentration from different materials. In fact, knowledge of the radon exhalation rate from building materials is important for understanding the individual contribution of each material to the total indoor radon exposure. Samples were hermetically closed in glass vessels and the radon growth was followed as a function of time. The radon exhalation rate was therefore derived from the experimental measurement of {alpha}-track densities. The radon exhalation varied from (5.77 {+-} 0.06) x 10{sup -5} to (7.61 {+-} 0.07) x 10{sup -5} Bq cm{sup -2} h{sup -1} in bricks, from (5.79 {+-} 0.05) x 10{sup -5} to (11.6 {+-} 0.12) x 10{sup -5} in tiles, and was (6.95 {+-} 0.03) x 10{sup -5} Bq cm{sup -2} h{sup -1} in concrete. A correlation (correlation coefficient approx. = 0.8) was found between radium concentration measured with a HPGe detector and the radon exhalation rate obtained using nuclear track detectors.

  9. (226)Ra, (232)Th and (40)K contents and radon exhalation rate from materials used for construction and decoration in Cameroon.

    Science.gov (United States)

    Ngachin, M; Garavaglia, M; Giovani, C; Nourreddine, A; Kwato Njock, M G; Scruzzi, E; Lagos, L

    2008-09-01

    This work deals with the measurement of radioactivity and radon exhalation rate from building materials manufactured in Douala city from geological materials. Nine types of building material were surveyed for their natural radioactivity contents using high-resolution gamma-ray spectrometry. The activity concentrations for (226)Ra, (232)Th and (40)K varied from 11.5 to 49 Bq kg(-1), 16 to 37 Bq kg(-1) and 306 to 774 Bq kg(-1), respectively. The absorbed dose rate in the samples investigated at 1 m above ground level ranged from 28.5 to 66.6 nGy h(-1). External and internal hazard indices were also estimated as defined by the European Commission. The Ra equivalents of the materials studied ranged from 57.5 to 133 Bq kg(-1) and are much smaller than the recommended limit of 370 Bq kg(-1) for construction materials for dwellings. Polycarbonate nuclear track detectors (NTDs), type CR-39, were used for measuring the radon concentration from different materials. In fact, knowledge of the radon exhalation rate from building materials is important for understanding the individual contribution of each material to the total indoor radon exposure. Samples were hermetically closed in glass vessels and the radon growth was followed as a function of time. The radon exhalation rate was therefore derived from the experimental measurement of alpha-track densities. The radon exhalation varied from (5.77 +/- 0.06) x 10(-5) to (7.61 +/- 0.07) x 10(-5) Bq cm(-2) h(-1) in bricks, from (5.79 +/- 0.05) x 10(-5) to (11.6 +/- 0.12) x 10(-5) in tiles, and was (6.95 +/- 0.03) x 10(-5) Bq cm(-2) h(-1) in concrete. A correlation (correlation coefficient approximately 0.8) was found between radium concentration measured with a HPGe detector and the radon exhalation rate obtained using nuclear track detectors.

  10. 230Th/ 234U/ 238U and 231Pa/ 235U ages from a single fossil coral fragment by multi-collector magnetic-sector inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Mortlock, Richard A.; Fairbanks, Richard G.; Chiu, Tzu-chien; Rubenstone, James

    2005-02-01

    The 230Th/ 234U/ 238U age dating of corals via alpha counting or mass spectrometry has significantly contributed to our understanding of sea level, radiocarbon calibration, rates of ocean and climate change, and timing of El Nino, among many applications. Age dating of corals by mass spectrometry is remarkably precise, but many samples exposed to freshwater yield inaccurate ages. The first indication of open-system 230Th/ 234U/ 238U ages is elevated 234U/ 238U initial values, very common in samples older than 100,000 yr. For samples younger than 100,000 yr that have 234U/ 238U initial values close to seawater, there is a need for age validation. Redundant 230Th/ 234U/ 238U and 231Pa/ 235U ages in a single fossil coral fragment are possible by Multi-Collector Magnetic Sector Inductively Coupled Plasma Mass Spectrometry (MC-MS-ICPMS) and standard anion exchange column chemistry, modified to permit the separation of uranium, thorium, and protactinium isotopes from a single solution. A high-efficiency nebulizer employed for sample introduction permits the determination of both 230Th/ 234U/ 238U and 231Pa/ 235U ages in fragments as small as 500 mg. We have obtained excellent agreement between 230Th/ 234U/ 238U and 231Pa/ 235U ages in Barbados corals (30 ka) and suggest that the methods described in this paper can be used to test the 230Th/ 234U/ 238U age accuracy. Separate fractions of U, Th, and Pa are measured by employing a multi-dynamic procedure, whereby 238U is measured on a Faraday cup simultaneously with all minor isotopes measured with a Daly ion counting detector. The multi-dynamic procedure also permits correcting for both the Daly to Faraday gain and for mass discrimination during sample analyses. The analytical precision of 230Th/ 234U/ 238U and 231Pa/ 235U dates is generally better than ±0.3% and ±1.5%, respectively (2 Relative Standard deviation [RSD]). Additional errors resulting from uncertainties in the decay constant for 231Pa and from undetermined

  11. Concentration in activity of {sup 137} Cs, {sup 40} K, {sup 232} Th, {sup 226} Ra in waste deposits of the benefits of minerals in the State of Zacatecas; Concentracion en actividad de {sup 137} Cs, {sup 40} K, {sup 232} Th, {sup 226} Ra en depositos de desecho del beneficio de minerales en el Estado de Zacatecas

    Energy Technology Data Exchange (ETDEWEB)

    Leal, B.; Mireles, F.; Quirino, L.; Davila, I.; Ramirez, F. [UAZ, A.P. 579C, 98068 Zacatecas (Mexico)

    2003-07-01

    The necessity to report the changes in the contained radionuclides in the terrestrial crust, or those deposited by the atomic tests around the world, becomes clear when observing the use of material of waste of those mines. With the purpose of quantifying the concentration in activity its were meet a series of waste samples in mines of the municipalities of Zacatecas, Fresnillo, Guadalupe and Veta Grande of the state of Zacatecas, Mexico. The analysis was carried out by gamma spectrometry with a HPGe detector with a resolution of 1.9 keV corresponding to an energy of 1.33 MeV calibrated in efficiency and energy by means of a certified standard multi nuclide in activity with identical geometry to that of the samples. The times of count are of 80000 seconds, with the purpose of to reduce the relative uncertainties and to define well the interest regions. The activity of {sup 226} Ra and {sup 232} Th is obtained through the one {sup 214} Bi and {sup 228} Ac respectively, the concentration was also measured in activity of the one {sup 40} K and the {sup 137} Cs in units of Bq kg{sup -1}. (Author)

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

    Science.gov (United States)

    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

  13. Determination of {sup 234}U and {sup 238}U activity concentrations in groundwaters from three deep wells drilled in Itu Intrusive Suite (SP); Determinacao das concentracoes de atividade de {sup 234}U e {sup 238}U em aguas subterraneas de tres pocos perfurados em rochas da Suite Intrusiva de Itu (SP)

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Francisca de

    2006-07-01

    Activity concentrations of ({sup 234}U) and ({sup 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 {sup 234}U in relation to {sup 238}U, indicating an important radioactive disequilibrium of these isotopes. In well I, the activity concentrations of ({sup 238}U) varied from (1,06 +- 0,03) to (2,1+- 0,2) mBq/L and those of ({sup 234}U) spanned from (3,1 +- 0,2) to (6,0 +- 0,4) mBq/L, whereas ({sup 234}U/{sup 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 ({sup 238}U) and ({sup 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 ({sup 234}U/{sup 238}U) activity ratios, spanning from (2,79 +- 0,07) to (8,1+- 0,3). In SY well, ({sup 238}U) activities varied between (0,8 +- 0,1) and (4,2 +- 0,3) mBq/L and those ones of ({sup 234}U) from (14 +- 1) to (53 +- 4) mBq/L, whereas ({sup 234}U/{sup 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 ({sup 234}U/{sup 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

  14. 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.

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

    International Nuclear Information System (INIS)

    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. 234Th (t½ = 24.1 days) is a particle-reactive radionuclide produced continuously in seawater by the decay of its soluble precursor conservative with salinity 238U (t½ = 4.5 109 years). Since 234Th presents relatively short half-life, it is used to quantify processes that occur in temporal scale varying from days to weeks. The disequilibrium 234Th/238U 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 CO2 atmospheric concentrations. The radionuclides 210Pb (t½ = 22.3 years) and 210Po (t½ = 138 days) are also particle-reactive. The disequilibrium 210Po/210Pb has been used to estimate fluxes of particles exported in the ocean in the time scale of weeks. The long-lived Ra isotopes, 226Ra (t½ = 1,600 years) and 228Ra (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 238U, 234Th, 22'6Ra, 22'8Ra, 210Pb and 210Po in the Bransfield Strait during 2 samplings carried out in the 2011 Austral Summer (OPERANTAR XXIX and XXX). (author)

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

    Science.gov (United States)

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

    2011-09-01

    To assess the quality of the environment in southern Iraq after the Gulf War II, a geochemical survey was carried out. The survey provided data on the chemistry of Euphrates waters, as well as the trace element contents, U and Pb isotopic composition, and PAH levels in soil and tree bark samples. The trace element concentrations and the (235)U/(238)U ratio values in the Euphrates waters were within the usual natural range, except for the high contents of Sr due to a widespread presence of gypsum in soils of this area. The trace element contents in soils agreed with the common geochemistry of soils from floodplain sediments. Some exceptions were the high contents of Co, Cr and Ni, which had a natural origin related to ophiolitic outcrops in the upper sector of the Euphrates basin. The high concentrations of S and Sr were linked to the abundance of gypsum in soils. A marked geochemical homogeneity of soil samples was suggested by the similar distribution pattern of rare earth elements, while the (235)U/(238)U ratio was also fairly homogeneous and within the natural range. The chemistry of the tree bark samples closely reflected that of the soils, with some notable exceptions. Unlike the soils, some tree bark samples had anomalous values of the (235)U/(238)U ratio due to mixing of depleted uranium (DU) with the natural uranium pool. Moreover, the distribution of some trace elements (such as REEs, Th and Zr) and the isotopic composition of Pb in barks clearly differed from those of the nearby soils. The overall results suggested that significant external inputs occurred implying that once formed the DU-enriched particles could travel over long distances. The polycyclic aromatic hydrocarbon concentrations in tree bark samples showed that phenanthrene, fluoranthene and pyrene were the most abundant components, indicating an important role of automotive traffic. PMID:21774965

  17. The radiochemical contamination (210Po and 238U of zone around phosphogypsum waste heap in Wiślinka (northern Poland

    Directory of Open Access Journals (Sweden)

    Boryło A.

    2013-04-01

    Full Text Available The aim of this work was the determination of the impact of phosphogypsum waste heap in Wiślinka (northern Poland for radiological protection of zone around waste heap. The activity of 210Po, 234U, and 238U were measured using an alpha spectrometer. The values of uranium and polonium concentration in water with immediate area of waste heap are considerably higher than in the waters of the Martwa Wisła river. The values of activity ratio 234U/238U are approximately about one in the phosphogypsum (0.97±0.05 and in the water of retention reservoir and pumping station (0.92±0.01 and 0.99±0.08, while in the water from the Martwa Wisła river they are slightly higher than one (1.03±0.07 and 1.17±0.06. In the analyzed plants species the highest amounts of polonium and uranium were found in ruderal plants samples as well as hygrophilous plant samples. The more amounts of 210Po and 238U radionuclides were accumulated mainly in the roots of the analyzed plant species. The significant source of polonium and uranium in the natural environment is dry and wet atmospheric fallout in the immediate vicinity of phosphogypsum waste heap and the transfer via root for distant areas. The general conclusion of realized study is higher influence of phosphogypsum on radioactive contamination of environmental zone around heap waste in Wiślinka (northern Poland.

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

    Science.gov (United States)

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

    2011-09-01

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

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

    Science.gov (United States)

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

    2016-08-01

    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. PMID:27108351

  20. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Riccobono, Francesco; Perra, Guido; Pisani, Anastasia; Protano, Giuseppe, E-mail: protano@unisi.it

    2011-09-01

    To assess the quality of the environment in southern Iraq after the Gulf War II, a geochemical survey was carried out. The survey provided data on the chemistry of Euphrates waters, as well as the trace element contents, U and Pb isotopic composition, and PAH levels in soil and tree bark samples. The trace element concentrations and the {sup 235}U/{sup 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 {sup 235}U/{sup 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 {sup 235}U/{sup 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: {yields} This is a contribution to the knowledge of the Iraqi environment

  2. 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)

    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 235U/238U 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 235U/238U 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 235U/238U 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 fluvial waters

  3. Natural isotopes 238U and 40K content in rigosol from the area of school estate good 'Radmilovac' of Faculty of Agriculture, Zemun

    OpenAIRE

    Vukašinović Ivana Ž.; Todorović Dragana J.; Đorđević Aleksandar R.; Rajković Miloš B.; Stojanović Mirjana D.; Pavlović Vladimir B.

    2009-01-01

    Distribution of natural gamma-emitting radionuclides 238U and 40K were determined in the soil profiles from the peach-trees field on experimental farm Radmilovac, southeast Belgrade. Internal soil morphology has been changed in 1992. when soil rigosol type with deep Ap-horizon (0-80 cm) has been formed by special treatment of parent soil, chernozem type. Gamma-spectrometry method is applied in measurement of radionuclide activities in soil samples by using hyperpure coaxial gamma-ray detector...

  4. Violence of heavy-ion reactions from neutron multiplicity: 11 to 20A MeV /sup 20/Ne+ /sup 238/U

    International Nuclear Information System (INIS)

    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

  5. 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)

  6. Accurate measurements of fission-fragment yields in 234,235,236,238U(γ,f with the SOFIA set-up

    Directory of Open Access Journals (Sweden)

    Chatillon A.

    2016-01-01

    Full Text Available SOFIA (Studies On Fission with Aladin is a new experimental set-up dedicated to accurate measurement of fission-fragments isotopic yields. It is located at GSI, the only place to use inverse kinematics at relativistic energies in order to study the (γ,f electromagnetic-induced fission. The SOFIA set-up is a large-acceptance magnetic spectrometer, which allows to fully identify both fission fragments in coincidence on the whole fission-fragment range. This paper will report on fission yields obtained in 234,235,236,238U(γ,f reactions.

  7. Synthesis of rutherfordium isotopes in the 238U(26Mg, xn)264-xRf reaction and study of their decay properties

    OpenAIRE

    Gates, J. M.

    2008-01-01

    Isotopes of rutherfordium (258-261Rf) were produced in irradiations of 238U targets with 26Mg beams. Excitation functions were measured for the 4n, 5n and 6n exit channels. Production of 261Rf in the 3n exit channel with a cross section of 28+92-26 pb was observed. Alpha decay of 258Rf was observed for the first time with an alpha-particle energy of 9.05+-0.03 MeV and an alpha/total decay branching ratio of 0.31+-0.11. In 259Rf, the electron capture/total decay branching ratio was measured t...

  8. 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)

    In this study the naturally occurring radionuclides 234Th and 238U 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 CO2 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 234Th 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 234Th activity concentrations varied from 1.4 to 2.9 dpm L-1. Highest total 234Th activities were found late in the austral summer season. Activity concentrations of dissolved 238U 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 234Th distribution was 22%. (author)

  9. 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)

  10. 238U-234U activity ratio as tracer of waterpathway within the watershed substratum: evidence of U data from the Strengbach and Ringelbach research catchments (Vosges , France)

    Science.gov (United States)

    Chabaux, F.; Schaffhausen, Th.; Pierret, M.-C.; Ambroise, B.

    2012-04-01

    U activity ratios were measured in spring and source waters collected in two small research watersheds developed on granitic bedrocks in Vosges Mountains (Eastern France), i.e., the Strengbach (http://ohge.u-strasbg.fr) and the Ringelbach catchments. The data indicates a clear relationship between the emerging altitude of sources/springs in each slope of the watersheds, and the intensity of 234U-238U activity ratios in the waters. Such a relationship can be readily explained through a scenario assuming that U mobilization in these waters and their 234U enrichment (consequence of the alpha recoil process) are controlled by the duration of the water-pathway within the substratum of the watershed: longer water pathway within the watershed, longer duration of water-rock interaction and hence higher 234U enrichment in the source/spring waters. The immediate consequence of such an interpretation is that (234U/238U) activity ratio in surface waters, at least at the scale of such small and elemental watersheds, might be a geochemical tracer useful to constrain a key hydrological parameter which controls, at least partly, the nature and the intensity of water-rock interactions in the watershed, namely the water pathway within the watershed substratum. The data also suggests that U activity ratios could be also very relevant to constrain the contribution of deep waters within surface waters. Future developments in this domain will certainly confirm the interest of U activity ratio as hydrological tracer of the water-rock interactions.

  11. Initial Design Calculations for a Detection System that will Observe Resonant Excitation of the 680 keV state in 238U

    Energy Technology Data Exchange (ETDEWEB)

    Pruet, J; Hagmann, C

    2007-01-26

    We present calculations and design considerations for a detection system that could be used to observe nuclear resonance fluorescence in {sup 238}U. This is intended as part of an experiment in which a nearly monochromatic beam of light incident on a thin foil of natural uranium resonantly populates the state at 680 keV in {sup 238}U. The beam of light is generated via Compton upscattering of laser light incident on a beam of relativistic electrons. This light source has excellent energy and angular resolution. In the current design study we suppose photons emitted following de-excitation of excited nuclei to be observed by a segmented array of BGO crystals. Monte Carlo calculations are used to inform estimates for the design and performance of this detector system. We find that each detector in this array should be shielded by about 2 cm of lead. The signal to background ratio for each of the BGO crystals is larger than ten. The probability that a single detector observes a resonant photon during a single pulse of the light source is near unity.

  12. Characterisation of airborne uranium and thorium contamination in northern England through measurement of U, Th and 235U/238U in tree bark.

    Science.gov (United States)

    Bellis, D J; Ma, R; McLeod, C W

    2001-02-01

    Samples of tree bark were collected from four locations in Northern England (a typical rural site, a coal-fired power station, a uranium (isotopic) enrichment plant and a nuclear fuel fabrication facility), to assess the nature and extent of airborne uranium and thorium contamination. The U and Th concentrations of bark were determined by inductively coupled plasma mass spectrometry after conventional nebulisation of bark digests, whilst measurement of 235U/238U isotopic ratio utilised high efficiency nebulisation. Uranium concentrations varied between and within the sites (range, 0.01-12 micrograms g-1), with maximum values recorded within 1 km of the nuclear fuel fabrication plant (Springfields). In comparison, the concentration of Th in bark was low (mean, 0.018 microgram g-1) at all sites with the exception of the area affected by coal combustion (0.2-0.8 microgram g-1). The U/Th ratio varied from 0.5 to 3900 compared with the average crustal ratio of 0.3. Low values (< 2) were recorded at the 'coal' and 'rural' sites whilst Capenhurst and Springfields showed high values indicating the relative magnitude of uranium elevation. Significant enrichment of the natural 235U/238U ratio (0.00725) was observed near the nuclear installations, in particular, the enrichment plant (Capenhurst). PMID:11354728

  13. Investigation of (235)U, (226)Ra, (232)Th, (40)K, (137)Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy.

    Science.gov (United States)

    Zare, Mohammad Reza; Kamali, Mahdi; Fallahi Kapourchali, Maryam; Bagheri, Hashem; Khoram Bagheri, Mahdi; Abedini, Ali; Pakzad, Hamid Reza

    2016-02-01

    Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. 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. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland. PMID:26490904

  14. Measurements of yields of fission products in the reaction of {sup 238}U with high-energy p, d and n beams

    Energy Technology Data Exchange (ETDEWEB)

    Nolen, J.A.; Ahmad, I.; Back, B.B. [and others

    1995-08-01

    An experiment was performed at the Michigan State University cyclotron to determine the yields of neutron-rich fission products in the reaction of {sup 238}U with 100-MeV neutrons, 200-MeV deuterons and 200-MeV protons. Several 1-mm-thick {sup 238}U foils were irradiated for 100-second intervals sequentially for each configuration and the ten spectra were added for higher statistics. The three successive spectra, each for a 40 s period, were accumulated for each sample. Ten foils were irradiated. Successive spectra allowed us to determine approximate half-lives of the gamma peaks. Several arrangements, which were similar to the setup we plan to use in our radioactive beam proposal, were used for the production of fission products. For the high-energy neutron irradiation, U foils were placed after a 5-inch-long, 1-inch-diameter Be cylinder which stopped the 200-MeV deuteron beam generating 100-MeV neutrons. Arrangements for deuteron irradiation included direct irradiation of U foils, placing U foils after different lengths of (0.5 inch, 1.0 inch and 1.5 inch) 2-inch diameter U cylinder. Since the deuteron range in uranium is 17 mm, some of the irradiations were due to the secondary neutrons from the deuteron-induced fission of U. Similar arrangements were also used for the 200-MeV proton irradiation of the {sup 238}U foils. In all cases, several neutron-rich fission products were identified and their yields determined. In particular, we were able to observe Sn in all the runs and determine its yield. The data show that with our proposed radioactive device we will be able to produce more than 10{sup 12} {sup 132}Sn atoms per second in the target. Assuming an overall efficiency of 1 %, we will be able to deliver one particle nanoampere of {sup 132}Sn beam at a target location. Detailed analysis of the {gamma}-ray spectra is in progress.

  15. Contents and daily intakes of gamma-ray emitting nuclides, 90Sr, and 238U using market-basket studies in japan

    International Nuclear Information System (INIS)

    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, 40K and U series such as 214Bi, and 212Pb, and Th series) were measured in each food group, and artificial radionuclides, 90Sr and 238U, 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 137Cs and 40K intakes (mBq/person · day) in the 13 cities were 12.5-90Sr 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 238U 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 214Bi and 212Pb, and Th series were lower than the lower detection limits in many samples, their daily intakes were not calculated. Regarding the daily intake of 137Cs from each food group, the intakes from fish and shellfish, milk, meat/eggs, and mushrooms/seaweed tended to be higher. The daily 40K intake from each food group varied among the areas, but the total intake from the 14 food groups was similar in all 13 cities. 40K from these foods accounted for most of the annual effective dose (μSv/person · year) of γ-ray emitting nuclides, and the doses of 40K, 90Sr, and 238U were 130-217, 0.21-0.55, and 0.10-0.51, respectively. (author)

  16. (238)U/(235)U isotope ratios of crustal material, rivers and products of hydrothermal alteration: new insights on the oceanic U isotope mass balance.

    Science.gov (United States)

    Noordmann, Janine; Weyer, Stefan; Georg, R Bastian; Jöns, Svenja; Sharma, Mukul

    2016-01-01

    In this study, the U isotope composition, n((238)U)/n((235)U), of major components of the upper continental crust, including granitic rocks of different age and post-Archaean shales, as well as that of rivers (the major U source to the oceans) was investigated. Furthermore, U isotope fractionation during the removal of U at mid-ocean ridges, an important sink for U from the oceans, was investigated by the analyses of hydrothermal water samples (including low- and high-temperature fluids), low-temperature altered basalts and calcium carbonate veins. All analysed rock samples from the continental crust fall into a limited range of δ(238)U between -0.45 and -0.21 ‰ (relative to NBL CRM 112-A), with an average of -0.30 ± 0.15 ‰ (2 SD, N = 11). Despite differences in catchment lithologies, all major rivers define a relatively narrow range between -0.31 and -0.13 ‰, with a weighted mean isotope composition of -0.27 ‰, which is indistinguishable from the estimate for the upper continental crust (-0.30 ‰). Only some tributary rivers from the Swiss Alps display a slightly larger range in δ(238)U (-0.29 to +0.01 ‰) and lower U concentrations (0.87-3.08 nmol/kg) compared to the investigated major rivers (5.19-11.69 nmol/kg). These findings indicate that only minor net U isotope fractionation occurs during weathering and transport of material from the continental crust to the oceans. Altered basalts display moderately enriched U concentrations (by a factor of 3-18) compared to those typically observed for normal mid-ocean ridge basalts. These, and carbonate veins within altered basalts, show large U isotope fractionation towards both heavy and light U isotope compositions (ranging from -0.63 to +0.27 ‰). Hydrothermal water samples display low U concentrations (0.3-1 nmol/kg) and only limited variations in their U isotope composition (-0.43 ± 0.25 ‰) around the seawater value. Nevertheless, two of the investigated fluids display

  17. MEASUREMENT OF PROMPT NEUTRON SPECTRA OF 238U FISSION INDUCED BY 10.17 AND 12.12 MeV NEUTRONS

    Institute of Scientific and Technical Information of China (English)

    李安利; 白希祥; 等

    1994-01-01

    Experimental method to measure the prompt neutron spectra of 238U fission induced by fast neutrons has been developed at HI-13 Tandem Van de Graaff Accelerator Laboratory of CIAE.These techniques employ a multi-segment fission chamber and two liquid scintillator neutron detectors.TOF(time of flight)techniques are used for primary neutrons to select the fission events induced by monoenergetic neutron from 2H(d,n) reactions instead of breakup neutrons from 2H(d,np) reactions.The fission neutron TOF spectra are measured in coincidence with the fission fragments to distinguish fission neutrons from other secondary neutrons.The method permits measurements to a fairly good accuracy under large neutron and gamma ray background.The techniques are described and experimental spectra are presented.

  18. Measurement of neutron transmissions from 0.52 eV to 4.0 keV through seven samples of 238U at 40 m

    International Nuclear Information System (INIS)

    Neutron transmissions through 1.5-, 5-, 10-, 30-, 100-, 425-, and 1425-mil samples of depleted 238U were measured from 0.52 eV to 4.0 keV using the ORELA pulsed electron linac neutron source and time-of-flight technique with a 1-mm 6Li-glass detector with a flight path of 40 m. The measurements are tabulated and compared with transmissions calculated from the ENDF/B-IV total cross section. In addition, the 1425-mil transmission from 50 to 300 eV is compared with transmissions calculated by using multilevel formalisms, and some neutron widths are extracted with area analysis and compared with those from previous measurements. 14 figures, 10 tables

  19. Natural isotopes 238U and 40K content in rigosol from the area of school estate good 'Radmilovac' of Faculty of Agriculture, Zemun

    Directory of Open Access Journals (Sweden)

    Vukašinović Ivana Ž.

    2009-01-01

    Full Text Available Distribution of natural gamma-emitting radionuclides 238U and 40K were determined in the soil profiles from the peach-trees field on experimental farm Radmilovac, southeast Belgrade. Internal soil morphology has been changed in 1992. when soil rigosol type with deep Ap-horizon (0-80 cm has been formed by special treatment of parent soil, chernozem type. Gamma-spectrometry method is applied in measurement of radionuclide activities in soil samples by using hyperpure coaxial gamma-ray detector, Canberra type. Investigation results has been shown that the natural activity contents obtained in the experiment are within the range of normal background activity according to UNSCEAR (2000 and that radionuclide activity decreased in the plant root zone. .

  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. 234U/238U isotope ratios in groundwater from Southern Nevada: a comparison of alpha counting and magnetic sector ICP-MS.

    Science.gov (United States)

    Cizdziel, James; Farmer, Dennis; Hodge, Vernon; Lindley, Kazumasa; Stetzenbach, Klaus

    2005-11-01

    The 234U/238U activity ratio (AR) is extensively used as a geochemical tool to investigate movement and flow relationships in major hydrological units, information that is particularly important when considering nuclear waste disposal. It is usually determined by radiochemical separation and concentration of U, followed by energy-specific alpha particle counting. Alternatively, sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) can be used to measure U isotopic signatures directly in groundwater samples. Here, we compare the two methods for samples of spring and groundwater from southern Nevada. Results for samples stripped from stainless steel disks, previously used for alpha counting, and for splits of groundwater samples show good agreement between the methods. However, SF-ICP-MS is faster, requires much less sample, and produces essentially no waste. We demonstrate applicability of the SF-ICP-MS method for groundwater collected from over 25 wells on and near the Nevada Test Site during 2003. Uranium concentrations ranged from 0.17 to 9.87 ppb with a mean of 2.9 ppb, while 234U/238U AR values ranged from 1.9 to 11.5 with a mean of 4.3. Groundwater collected from deep wells in the northern part of the study area tended to have moderate to high U concentrations and AR values, possibly representative of older volcanic-type waters, whereas groundwater from wells in the Fortymile Wash area had relatively low AR and U concentrations, suggesting younger waters with a possible local recharge component. PMID:16227084

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

    OpenAIRE

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

    2015-01-01

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

  3. 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

  4. Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia.

    Science.gov (United States)

    Alshahri, Fatimh; Alqahtani, Muna

    2015-06-01

    The specific activities of (238)U, (226)Ra, (40)K, and (222)Rn in chemical fertilizers were measured using gamma ray spectrometer and Cr-39 detector. In this study, 21 chemical fertilizers were collected from Eastern Saudi Arabian markets. The specific activities of (238)U ranged from 23 ± 0.5 to 3900 ± 195 Bq kg(-1); (226)Ra ranged from 5.60 ± 2.80 to 392 ± 18 Bq kg(-1); and (40)K ranged from 18.4 ± 3 to 16,476 ± 820 Bq kg(-1). The radon concentrations and the radon exhalation rates were found to vary from 3.20 ± 1.20 to 1532 ± 160 Bq m(-3) and from 1.60 to 774 mBq m(-2) h(-1), respectively. Radium equivalent activities (Raeq) were calculated for the analyzed samples to assess the radiation hazards arising due to the use of these chemical fertilizers in the agriculture soil. The Raeq for six local samples (nitrogen, phosphorous, and potassium (NPK) and single superphosphate (SSP)) and one imported sample (Sulfate of Potash (SOP)) were greater than the acceptable value 370 Bq kg(-1). The total air absorbed doses rates in air 1 m above the ground (D) were calculated for all samples. All samples, except one imported granule sample diammonium phosphate (DAP), were higher than the estimated average global terrestrial radiation of 55 nGy h(-1). The highest annual effective dose was in triple super phosphate (TSP) fertilizers (2.1 mSv y(-1)). The results show that the local TSP, imported SOP, and local NPK (sample 13) fertilizers were unacceptable for use as fertilizers in agricultural soil. Furthermore, the toxic elements and trace metals (Pb, Cd, Cr, Co, Ni, Hg, and As) were determined using atomic absorption spectrometer. The concentrations of chromium in chemical fertilizers were higher than the global values.

  5. Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia.

    Science.gov (United States)

    Alshahri, Fatimh; Alqahtani, Muna

    2015-06-01

    The specific activities of (238)U, (226)Ra, (40)K, and (222)Rn in chemical fertilizers were measured using gamma ray spectrometer and Cr-39 detector. In this study, 21 chemical fertilizers were collected from Eastern Saudi Arabian markets. The specific activities of (238)U ranged from 23 ± 0.5 to 3900 ± 195 Bq kg(-1); (226)Ra ranged from 5.60 ± 2.80 to 392 ± 18 Bq kg(-1); and (40)K ranged from 18.4 ± 3 to 16,476 ± 820 Bq kg(-1). The radon concentrations and the radon exhalation rates were found to vary from 3.20 ± 1.20 to 1532 ± 160 Bq m(-3) and from 1.60 to 774 mBq m(-2) h(-1), respectively. Radium equivalent activities (Raeq) were calculated for the analyzed samples to assess the radiation hazards arising due to the use of these chemical fertilizers in the agriculture soil. The Raeq for six local samples (nitrogen, phosphorous, and potassium (NPK) and single superphosphate (SSP)) and one imported sample (Sulfate of Potash (SOP)) were greater than the acceptable value 370 Bq kg(-1). The total air absorbed doses rates in air 1 m above the ground (D) were calculated for all samples. All samples, except one imported granule sample diammonium phosphate (DAP), were higher than the estimated average global terrestrial radiation of 55 nGy h(-1). The highest annual effective dose was in triple super phosphate (TSP) fertilizers (2.1 mSv y(-1)). The results show that the local TSP, imported SOP, and local NPK (sample 13) fertilizers were unacceptable for use as fertilizers in agricultural soil. Furthermore, the toxic elements and trace metals (Pb, Cd, Cr, Co, Ni, Hg, and As) were determined using atomic absorption spectrometer. The concentrations of chromium in chemical fertilizers were higher than the global values. PMID:25532871

  6. 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)

    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)

  7. 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.

  8. Sub-barrier resonance fission and its effects on fission fragment properties, exemplified on 234,238U(n,f

    Directory of Open Access Journals (Sweden)

    Oberstedt S.

    2013-03-01

    Full Text Available The correlation between the sub-barrier resonant behaviour of fission crosssection of non-fissile actinides (pre-scission stage and the visible fluctuations of their fission fragment and prompt neutron data (post-scission stage around the incident energies of sub-barrier resonances is outlined and supported by quantitative results for two fissioning systems 234,238U(n,f. These quantitative results refer to both stages of the fission process: a The pre-scission stage including the calculation of neutron induced cross-sections with focus on fission. Calculations are done in the frame of the refined statistical model for fission with sub-barrier effects also extended to take into account the multi-modal fission. b The post-scission stage including the prompt neutron emission treated in the frame of the Point-by-Point model. Total quantities characterizing the fission fragments and the prompt neutrons obtained by averaging the Point-by-Point results as a function of fragment over the fission fragment distributions reveal variations around the energies of sub-barrier resonances in the fission crosssection.

  9. Energy Dependence of Neutron-Induced Fission Product Yields of 235U, 238U and 239Pu Between 0.5 and 14.8 MeV

    Science.gov (United States)

    Gooden, Matthew; Tornow, Werner; Tonchev, Anton; Vieira, Dave; Wilhelmy, Jerry; Arnold, Charles; Fowler, Malcolm; Stoyer, Mark

    2014-09-01

    Under a joint collaboration between TUNL-LANL-LLNL, a set of absolute fission product yield measurements have been performed. The energy dependence of a number of cumulative fission products between 0.5 and 14.8 MeV 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 activation utilizing specially designed dual-fission chambers and γ-ray counting. The dual-fission chambers are back-to-back ionization chambers encasing a target with thin deposits of the same target isotope in each chamber. This method allows for the direct measurement of the fission rate in the activation target with no reference to the fission cross-section, reducing uncertainties. γ-ray counting was performed on well-shield HPGe detectors over a period of 2 months per activation to properly identify fission products. Reported are absolute cumulative fission product yields for incident neutron energies of 0.5, 1.37, 2.4, 4.6 and 14.8 MeV.

  10. On an Increase of Critical Current in High Temperature Superconductors Doped with $^{238}U$ Due to the Production of Nuclear Photofission Fragment Tracks

    CERN Document Server

    Goncharov, I N

    2001-01-01

    The effect of appreciable increasing J_c(B,T) in HTSC (especially at liquid nitrogen temperatures of 62-78 K and magnetic fields of above 0.5 T) due to the production of fast heavy ion tracks, including those of doped U nuclear fission fragments, is known. The tracks are additional effective pinning-centers. The results described in the literature have been obtained for {235}U doped HTSC after reactor thermal neutron irradiations. Disadvantages of such a method are analyzed in this paper, in particular in case of its use for current-carrying Bi-2223/Ag tape, because a very high radioactivity level slowly decreasing in time arises. The author has suggested to use {238}U nuclear photofission in over a giant resonance energy range (E_gamma ~10-20 MeV). The experimental results obtained after tape irradiation with gamma-quanta (E_gamma \\leq 24 MeV), including a time dependence of radioactivity level, are presented. Possibilities of practical realization of this method are discussed.

  11. 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)

    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 238U(n14,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)=102-109 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)

  12. Transfer of long-lived radionuclides from diet to man and their body content and physiological characteristics of Reference Japanese Man

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Hisao; Shiraishi, Kunio; Igarashi, Yasuhito [National Inst. of Radiological Sciences, Nakaminato, Ibaraki (Japan). Nakaminato Lab. Branch Office; Yamamoto, Masayoshi; Tanaka, Gi-ichiro

    1994-03-01

    Intake and body content of actinides (Pu, Th, U) and a related alpha-emitting nuclide (Ra) were studied along with physiological aspects of Reference Japanese Man as the basic model for dosimetry. The ultimate purpose of the program was to examine applicability of the ICRP models and parameters (for workers) to members of the public. The result of an interlaboratory comparison of {sup 239}Pu+{sup 240}Pu determination including our result was published. Alpha spectrometric determinations of {sup 226}Ra in bone yielded representative adult bone concentration levels in Tokyo, 0.42 (mean) and 0.35 (median) mBq/g ash. The Ra-Ca O.R. (bone-diet) was obtained which was similar to the values in Sapporo and Kyoto. Specific effective energies for alpha radiation from {sup 226}Ra and its daughters were calculated using the ICRP dosimetric model for bone and masses of source and target organs of Reference Japanese Man. Annual dose equivalents in red marrow and bone surfaces were 10 and 145 {mu}Sv as estimated from the median adult bone Ra concentration. Diet samples collected by the duplicate portion method from 31 locations in Japan in summer and winter, 1981-2 were analysed for {sup 232}Th and {sup 238}U by the newly developed ICP-MS technique. The daily intake per person of {sup 232}Th and {sup 238}U were 1.7 and 8.8 mBq, respectively. Using IDES with Japanese physical parameters and other parameters of ICRP, weighted dose equivalent commitments for single year intakes were estimated as 0.4 {mu}Sv for {sup 232}Th and 0.3 {mu}Sv for {sup 238}U. Reference Japanese data including the adult, adolescent, child and infant of both sexes was extensively studied by Tanaka as part of the activities associated with the ICRP Task Group on Reference Man Revision. Normal data on the physical measurements, mass and dimensions of internal organs and body surfaces and some of the body composition were analyzed in relation to the nutritional conditions of the Japanese population. (J.P.N.).

  13. 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)

  14. Determination of 238 U,226 Ra and the Calculation of Equilibrium Coefficient in Rock of Gangdise Tectonic Belt,Tibet%西藏冈底斯构造带岩(矿)石中238U 、226Ra测定及铀镭平衡系数计算

    Institute of Scientific and Technical Information of China (English)

    齐玲

    2015-01-01

    通过对西藏冈底斯构造带岩矿石中铀、镭测定结果的初步研究发现,铀矿(化)体中铀、镭平衡系数趋于1,而区内铀含量较低的水系沉积物、花岗岩、酸性火山岩等显示较强的偏镭特征。%The Gangdise tectonic belt is an important part of the Tethyan tectonic domain ,preliminary study on the dctermination result of 238 U and 226 Ra in the rocks and ores from the belt found that equilib‐rium coefficient of the uranium‐radium tends to 1 in uranium mineralized bodies , but low uranium content rock of river sediments , granite and acid volcanic is characterized by rich radium .

  15. Angular correlations of fission fragments from the reactions 232Th(p,p'f) and 236U(p,p'f) at a projectile energy of 26.5 MeV

    International Nuclear Information System (INIS)

    Angular correlations of fission fragments from the reactions 232Th(p,p'f) and 236U(p,p'f) have been measured at a projectile energy of Ep=26.5 MeV and excitation energies up to the second chance fission. The scattered protons have been detected by a semiconductor telescope positioned at two different angles (vTel=90 and vTel=60 ). The fission fragments have been measured by a parallel plate avalanche detector, which was position sensitive in two dimensions. The data continuously cover the angular ranges of about -15 up to +95 for vTel=90 and about -5 up to +50 for vTel=60 with respect to the kinematical recoil axis. It succeeded to describe the changes of the angular distribution with increasing excitation energy in terms of the Transition State Model by a uniform increase of the contributions with K≠0 for both compound systems and both excitation reactions. (orig./DG)

  16. Measurement of the {sup 232}thorium capture cross section at n-TOF-CERN; Mesure de la section efficace de capture neutronique du {sup 232}Th a n-TOF au CERN

    Energy Technology Data Exchange (ETDEWEB)

    Aerts, G

    2005-09-01

    Within the context of nuclear power as a sustainable energy resource, a program of research is concentrated on a new nuclear fuel cycle based on thorium. The main advantage, as compared to the uranium cycle, is a lower production of minor actinides, of which the radiological impact on the long term constitutes a problem. At present, nuclear data libraries don't provide cross sections of a good enough quality, allowing more realistic calculations from simulations related to these reactors. The {sup 232}Th neutron capture cross section is an example. With the n-TOF collaboration, the measurement of this reaction was achieved in 2002 using two C{sub 6}D{sub 6} detectors. The experimental area located at CERN, is characterized by an outstanding neutron energy resolution coupled to a high instantaneous neutron flux. The determination of the gamma-ray cascade detection efficiency, with a random behaviour, has been obtained by the use of weighting functions. These were deduced from Monte Carlo simulations with the code MCNP. Data extraction, reduction, and the description of the neutron flux have lead to the capture yield. In the resolved resonance region, the resonance parameters describing the cross section were deduced with the code SAMMY, using the R-matrix theory. In the unresolved resonance region, an uncertainty of 3,5% is found, and a comparison with recent measurements shows a good agreement. (author)

  17. Thallium, uranium, and 235U/238U ratios in the digestive gland of American lobster (Homarus americanus) from an industrialized harbor

    International Nuclear Information System (INIS)

    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

  18. 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)

    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 (234U/238U) was applied to the geochemistry of local water sources. The uranium analysis procedure consisted of the following steps: adition of 232U-228Th 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 238U→234Th decay, the 234Th ejection to the solution was confirmed as the most important factor responsible for the extreme observed isotopic fractionation. (Author)

  19. The Role of Plants in the 238U-234U Disequilibria of Stream Waters: The Example of the Strengbach Watershed (Vosges, France)

    Science.gov (United States)

    Pierret, M.; Chbaaux, F.

    2004-12-01

    Recent TIMS or MC ICPMS analyses of U disequilibria in the dissolved load of stream and river waters have confirmed the potential of the U activity ratio in river waters as a specific tracer of chemical fluxes coming from rocks and soils (e.g., 1). These precise measurements have also outlined that occurrence of U activity ratios lower than one in dissolved load of river waters is not exceptional, especially at the scale of small watersheds. Such U values pose in turn the question of the real mechanisms controlling the supply of 234U-238U isotopes to the freshwaters. In order to address this question U activity ratios, Sr isotope ratios and the concentrations of major and some trace elements were analyzed in the different compartments of a small granitic watershed: the Strengbach environmental observatory (Vosges, France) ( http://ohge.u-strasbg.fr). In addition of the different streamwaters draining this watershed, the main horizons of weathering profiles, the associated soil solutions and the main tree species growing around were analyzed. The data confirm that the Strengbach stream water samples have generally U activity ratios lower than one and point out that soils solutions display a similar range of U and Sr variations. By contrast, tree and plant samples define different trends of variation in a plot of U activity ratios against Sr isotope ratios with, above all, U activity ratios systematically greater than one. These data show that trees and plants collected during this work cannot directly pomp their nutriments from soils and soil solutions sampled here, i.e. gravity solutions. They also suggest that, in this watershed, the plants, especially trees, play a central role in the weathering processes of rocks and minerals, and control a large part of the geochemical signature of the water samples collected on this watershed, including their U activity ratios. 1Riotte J and Chabaux F. (1999) GCA 63, 1263-1275.

  20. 234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California, USA

    Science.gov (United States)

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

    2013-01-01

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

  1. Thallium, uranium, and {sup 235}U/{sup 238}U ratios in the digestive gland of American lobster (Homarus americanus) from an industrialized harbor

    Energy Technology Data Exchange (ETDEWEB)

    Chou, C.L.; Uthe, J.F. [Dept. of Fisheries and Oceans, Halifax (Canada)

    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{center_dot}{sup -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 < 5 ng U{center_dot}g{sup -1} in the flesh. Trout bone contained 40 ng U{center_dot}g{sup -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 {sup 235U}/{sup 238U} ratios in it. 15 refs., 1 fig., 3 tabs.

  2. Fusion and fission properties of rapidly rotating nuclei 40Ar + 238U → 278110 at E/sub cm/ = 291 MeV

    International Nuclear Information System (INIS)

    Coincident fission fragments were detected to study the complete capture reaction, 40Ar + 238U → 278110 → f, at E/sub cm/ = 291 MeV (E/sub lab/ = 340 MeV). The detection system had a high efficiency to detect and subsequently veto events showing evidence of incomplete momentum transfer. The angular distribution of fission fragments was obtained between the center-of-mass angles of 1190 and 1640. The mass distributions of the fission fragments were also obtained for these angles. One non-coincident measurement made at theta/sub cm/ = 43.70 confirmed the symmetry of the angular distribution about 900. This study is distinguished from other recent studies by the use of a novel veto technique. This is the first measurement which has not been compromised by contamination with incomplete momentum-transfer reactions due to either pre-equilibrium emission or fission following deeply inelastic scattering. This is also the first investigation which reports detailed angular distributions with a majority (approx. 90%) of the capture cross section leading to nuclei having vanishing fission barriers. The rotating liquid-drop-model parameters were extracted from the data. The RLDM shapes along with statistical fission models, when applied to all partial waves, fail to reproduce the angular distributions. We interpret the angular distributions by applying statistical-equilibrium models and RLDM shapes for the nonvanishing fission-barrier partial waves and by assuming that the vanishing fission-barrier partial-wave contribution is given by l/sin theta. A l/sin theta distribution is expected for a system which has not reached complete statistical equilibrium and maintains a memory of its entrance channel, with the fission fragments being emitted in the reaction plane defined by the initial contact

  3. 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.

  4. Seasonal and spatial variability of {sup 210}Po, {sup 238}U and {sup 239+240}Pu levels in the river catchment area assessed by application of neural-network based classification

    Energy Technology Data Exchange (ETDEWEB)

    Skwarzec, Bogdan [University of Gdansk, Faculty of Chemistry, Chair of Analytical Chemistry, 18/19 Sobieskiego Street, 80-952 Gdansk (Poland)], E-mail: bosk@chem.univ.gda.pl; Kabat, Krzysztof [University of Gdansk, Faculty of Chemistry, Chair of Analytical Chemistry, 18/19 Sobieskiego Street, 80-952 Gdansk (Poland); Astel, Aleksander [Pomeranian Academy, Biology and Environmental Protection Institute, Environmental Chemistry Research Unit, 22a Arciszewskiego Street, 76-200 Slupsk (Poland)

    2009-02-15

    The present study deals with the application of self-organizing maps (SOM) in order to model, classify and interpret seasonal and spatial variability of {sup 210}Po, {sup 238}U and {sup 239+240}Pu levels in the Vistula river basin. The data set represents concentration values for 3 alpha emitters ({sup 210}Po, {sup 238}U and {sup 239+240}Pu) measured in surface water samples collected at 19 different sampling locations (8 in major Vistula stream while 11 in right or left Vistula tributaries) during four seasons (winter, spring, summer and autumn) in the framework of a one-year quality monitoring study. The advantages of an SOM algorithm, its classification and visualization ability for environmental data sets, are stressed. The neural-network based classification made it possible to reveal specific patterns related to both seasonal and spatial variability. In the middle and upper part of Vistula catchment as well as in the right-shore tributaries, concentrations of {sup 210}Po and {sup 238}U during summer and winter are the lowest. Concentrations of {sup 210}Po and {sup 238}U increase significantly during spring and autumn in the Vistula river catchment, especially in the delta of Vistula river. High concentration of anthropogenic originated {sup 239+240}Pu indicates 'site-specific' character of pollution in two large left-shore tributaries located in the middle part of the Vistula drainage area. Efficient classification of sampling locations could lead to an optimization of river radiochemical sampling networks and to a better tracing of natural and anthropogenic changes along Vistula river stream.

  5. Neutron Energy Spectra from Neutron Induced Fission of 235U at 0.95 MeV a of 238U at 1.35 and 2.02 MeV

    International Nuclear Information System (INIS)

    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

  6. Mid-ocean ridge basalt generation along the slow-spreading, South Mid-Atlantic Ridge (5-11°S): Inferences from 238U-230Th-226Ra disequilibria

    Science.gov (United States)

    Turner, Simon; Kokfelt, Thomas; Hauff, Folkmar; Haase, Karsten; Lundstrom, Craig; Hoernle, Kaj; Yeo, Isobel; Devey, Colin

    2015-11-01

    U-series disequilibria have provided important constraints on the physical processes of partial melting that produce basaltic magma beneath mid-ocean ridges. Here we present the first 238U-230Th-226Ra isotope data for a suite of 83 basalts sampled between 5°S and 11°S along the South Mid-Atlantic Ridge. This section of the ridge can be divided into 5 segments (A0-A4) and the depths to the ridge axis span much of the global range, varying from 1429 to 4514 m. Previous work has also demonstrated that strong trace element and radiogenic isotope heterogeneity existed in the source regions of these basalts. Accordingly, this area provides an ideal location in which to investigate the effects of both inferred melt column length and recycled materials. 226Ra-230Th disequilibria indicate that the majority of the basalts are less than a few millennia old such that their 230Th values do not require any age correction. The U-Th isotope data span a significant range from secular equilibrium up to 32% 230Th excess, also similar to the global range, and vary from segment to segment. However, the (230Th/238U) ratios are not negatively correlated with axial depth and the samples with the largest 230Th excesses come from the deepest ridge segment (A1). Two sub-parallel and positively sloped arrays (for segments A0-2 and A3 and A4) between (230Th/238U) and Th/U ratios can be modelled in various ways as mixing between melts from peridotite and recycled mafic lithologies. Despite abundant evidence for source heterogeneity, there is no simple correlation between (230Th/238U) and radiogenic isotope ratios suggesting that at least some of the trace element and radiogenic isotope variability may have been imparted to the source regions >350 kyr prior to partial melting to produce the basalts. In our preferred model, the two (230Th/238U) versus Th/U arrays can be explained by mixing of melts from one or more recycled mafic lithologies with melts derived from chemically heterogeneous

  7. Distribution characteristics of radium isotopes and their influence factors in the water of Jiaozhou Bay area

    International Nuclear Information System (INIS)

    Background: The interaction between continental and oceanic process is much intense in coastal region. The terrestrial freshwater mixes with seawater here which leads to the chemical constituents in water undergo rapid change. Purpose: The aim is to analyze and study the distribution characteristics of 224Ra and 226Ra and their influence factors in the water of Jiaozhou Bay area. Methods: The water samples of 224Ra and 226Ra were collected from groundwater, river water and seawater around the Jiaozhou Bay from April to May, 2012. In the laboratory, the activities of 224Ra absorbed on the Mn-fiber were measured through the continuous emanation method. Finally, the Mn-fiber was sealed for more than 7 days, and the activities of 226Ra absorbed on the Mn-fiber were measured through the direct emanation method. Results: The results show that the activities of 224Ra and 226Ra in groundwater and river water are much higher in the granitic area which has higher concentration of 232Th and 238U. Because of mixing with seawater, the salinity of groundwater and river water in coastal region rises which leads to the increasing amounts of 224Ra and 226Ra desorbed from the particles, resulting in higher activities of 224Ra and 226Ra in coastal region. Affected by the input of river (dissolved and desorbed from suspended particles) and submarine groundwater discharge (SGD), the activities of 224Ra and 226Ra are relatively higher in nearshore seawater, then with the decay of 224Ra and mixing dilution effect of the offshore seawater, the activities of 224Ra gradually decrease from nearshore region to the open ocean. The activities of 226Ra in the seawater of Jiaozhou Bay remain high-level values, and there are only a few zones of low 226Ra activities. The main reasons are that the activities of 226Ra from terrestrial freshwater are close to those from offshore seawater and the half-life of 226Ra is very long. Conclusion: The activities of 224Ra and 226Ra in groundwater relate to the

  8. 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)

  9. {sup 90}Sr, {sup 238}U, {sup 234}U, {sup 137}Cs, {sup 40}K and {sup 239/240}Pu in Emmental type cheese produced in different regions of Western Europe

    Energy Technology Data Exchange (ETDEWEB)

    Froidevaux, P. E-mail: pascal.froidevaux@inst.hospvd.ch; Geering, J.-J.; Pillonel, L.; Bosset, J.-O.; Valley, J.-F

    2004-07-01

    A method is presented for the determination of {sup 90}Sr and uranium in Emmental type cheese collected in dairy plants from different European countries. Results display a significant correlation (r=0.708, Student t-test=6.02) between the {sup 90}Sr content of the cheese and the altitude of grazing. The highest {sup 90}Sr activity is 1.13 Bq kg{sup -1} of cheese and the lowest is 0.29 Bq kg{sup -1}. Uranium activity is very low with a highest {sup 238}U value of 27 mBq kg{sup -1}. In addition, {sup 234}U/{sup 238}U ratio shows a large enrichment in {sup 234}U for every location. Without any significant indication of the geographic origin of the cheese, this enrichment is believed to be due to the geological features of the pasture, soil and underground water. These results tend to prove that the contamination of milk by uranium originates principally from the water that the cows drink instead of the forage. This finding may have a great importance in models dealing with dairy food contamination by radionuclides following a nuclear accident. Also, the {sup 90}Sr content and to a lesser extent the {sup 234}U/{sup 238}U ratio could be used to trace the authenticity of the origin of the cheese. {sup 137}Cs activity is lower than the detection limit of 0.1 Bq kg{sup -1} in all the samples collected (n=20). Based on natural {sup 40}K activity in cheese (15-21 Bq kg{sup -1}), the decontamination factor for the alkaline cations from milk to cheese is about 20. Plutonium activity stays below the detection limit of 0.3 mBq kg{sup -1}.

  10. 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.

  11. Measurement of the 238U neutron-capture cross section and gamma-emission spectra from 10 eV to 100 keV using the DANCE detector at LANSCE

    International Nuclear Information System (INIS)

    A careful new measurement of the 238U(n,γ) cross section from 10 eV to 100 keV has been made using the DANCE detector at LANSCE. DANCE is a 4π calorimetric scintillator array consisting of 160 BaF2 crystals. Measurements were made on a 48 mg/cm2 depleted uranium target. The cross sections are in general good agreement with previous measurements. The gamma-ray emission spectra, as a function of gamma multiplicity, were also measured and compared to model calculations.

  12. Measurement of the 238U neutron-capture cross section and gamma-emission spectra from 10 eV to 100 keV using the DANCE detector at LANSCE

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, John L [Los Alamos National Laboratory; Couture, A J [Los Alamos National Laboratory; Keksis, A L [Los Alamos National Laboratory; Vieira, D J [Los Alamos National Laboratory; O' Donnell, J M [Los Alamos National Laboratory; Jandel, M [Los Alamos National Laboratory; Haight, R C [Los Alamos National Laboratory; Rundberg, R S [Los Alamos National Laboratory; Kawano, T [Los Alamos National Laboratory; Chyzh, A [NORTH CAROLINA STATE UNIV; Baramsai, B [NORTH CAROLINA STATE UNIV; Wu, C Y [LLNL; Mitchell, G E [NORTH CAROLINA STATE UNIV; Becker, J A [LLNL; Krticka, M [CHARLES UNIV

    2010-01-01

    A careful new measurement of the {sup 238}U(n,{gamma}) cross section from 10 eV to 100 keV has been made using the DANCE detector at LANSCE. DANCE is a 4{pi} calorimetric scintillator array consisting of 160 BaF{sub 2} crystals. Measurements were made on a 48 mg/cm{sup 2} depleted uranium target. The cross sections are in general good agreement with previous measurements. The gamma-ray emission spectra, as a function of gamma multiplicity, were also measured and compared to model calculations.

  13. 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)

  14. Determination of 234U/238U ratio: Comparison of multi-collector ICPMS and ICP-QMS for water, hair and nails samples, and comparison with alpha-spectrometry for water samples

    International Nuclear Information System (INIS)

    The 234U/238U ratio in water, hair and nails samples was determined by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) and by alpha-spectrometry for the water samples only. A correlation of 0.99 was found between the two ICPMS methods and of 0.98 with alpha-spectrometry. The range of activity ratios was between 0.9 and 2.6 according to the MC-ICPMS measurements. The reproducibility of both ICPMS techniques was better than 4% for water samples containing 1μg l-1 of uranium and a 234U/238U atom ratio of 54.9 x 10-6. Sample preparation for the ICPMS consisted of dilution of water samples containing >10 μg l-1 of uranium and measurement time was ∼1 min, while alpha-spectrometry involved pre-concentration and separation of the uranium and counting times of 1000 min. (authors)

  15. Sorption behavior of U(VI), 234U(VI) and 238U(VI) onto fracture-filling clays in Beishan granite, Gansu: Application to selecting the site of high-level radwaste repository in China

    Institute of Scientific and Technical Information of China (English)

    MIN; Maozhong; LUO; Xingzhang; WANG; Ju; JIN; Yuanxin; WAN

    2005-01-01

    The first results of sorption experiments of U(VI), 234U(VI) and 238U(VI) onto original (unpurified) fracture-filling clays from No.1 monzonitic granite intrusion, Beishan area, Gansu Province, China are reported. The monzonitic granite intrusion is a potential location for a high-level radwaste (HLW) repository in China. The present experimental results show that the maximum U(VI) sorption reached 92% at near-neutral Ph and the distribution coefficient (Kd) was 1226 Ml/g. A high sorption capacity of the fracture-filling clays in host rock on radioactive elements is necessary for HLW deep geological disposal repository. No preferential sorption of 234U onto the clays was found. Finally, the sorption of U(VI) onto the clays was also modeled using a surface complexation model.

  16. Spin-alignment and g-factor measurement of the I{sup {pi}}=12{sup +} isomer in {sup 192}Pb produced in the relativistic-energy fragmentation of a {sup 238}U beam

    Energy Technology Data Exchange (ETDEWEB)

    Kmiecik, M.; Maj, A.; Ciemala, M.; Grebosz, J.; Lach, M.; Maier, K.H.; Mazurek, K.; Meczynski, W.; Myalski, S.; Styczen, J.; Zieblinski, M. [H. Niewodniczanski Inst. of Nuclear Physics PAN, Krakow (Poland); Gerl, J.; Becker, F.; Caceres, L.; Doornenbal, P.; Gorska, M.; Grawe, H.; Kojuharov, I.; Prokopowicz, W.; Saito, N.; Saito, T.R.; Wollersheim, H.J. [GSI, Darmstadt (Germany); Neyens, G.; Mallion, S.; Vermeulen, N. [Inst. voor Kern- en Stralingsfysica, K.U. Leuven (Belgium); Atanasova, L.; Detistov, P. [Univ. of Sofia ' St. Kl. Ohridski' (Bulgaria). Faculty of Physics; Balabanski, D.L. [Univ. degli Studi di Camerino (Italy); INFN sez. Perugia, Dipt. di Fisica, Camerino (Italy); Bulgarian Academy of Sciences, Inst. for Nuclear Research and Nuclear Energy, Sofia (Bulgaria); Bednarczyk, P. [H. Niewodniczanski Inst. of Nuclear Physics PAN, Krakow (Poland); GSI, Darmstadt (Germany); Benzoni, G.; Blasi, N.; Brambilla, S.; Million, B.; Wieland, O. [INFN Sez. di Milano (Italy); Bracco, A.; Camera, F.; Crespi, F.C.L.; Leoni, S.; Montanari, D. [INFN Sez. di Milano (Italy); Univ. degli Studi di Milano (Italy); Chamoli, S.K.; Hass, M.; Lakshmi, S. [Weizman Inst. of Science, Rehovot (Israel); Chmel, S. [Fraunhofer INT, Euskirchen (Germany); Daugas, J.M. [CEA, DAM, DIF, Arpajon Cedex (France); Georgiev, G. [Univ. Paris-Sud 11, CNRS/IN2P3, CSNSM, Orsay-Campus (France); Gladnishki, K. [Univ. of Sofia ' St. Kl. Ohridski' (Bulgaria). Faculty of Physics; Univ. degli Studi di Camerino (Italy); INFN sez. Perugia, Dipt. di Fisica, Camerino (Italy); Hoischen, R.; Rudolph, D. [Lund Univ., Dept. of Physics, Lund (Sweden); Ilie, G. [Univ. zu Koeln, Inst. fuer Kernphysik, Koeln (Germany); National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Ionescu-Bujor, M. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Jolie, J. [Univ. zu Koeln, Institut fuer Kernphysik, Koeln (Germany)] [and others

    2010-08-15

    The feasibility of measuring g -factors using the TDPAD method applied to high-energy, heavy fragmentation products is explored. The 2623keV I{sup {pi}}=12{sup +} isomer in {sup 192}Pb with {tau}=1.57{mu}s has been produced using the fragmentation of a 1A GeV {sup 238}U beam. The results presented demonstrate for the first time that such heavy nuclei produced in a fragmentation reaction with a relativistic beam are sufficiently well spin-aligned. Moreover, the rather large value of the alignment, 28(10)% of the maximum possible, is preserved during the separation process allowing the determination of magnetic moments. The measured values of the lifetime, {tau}=1.54(9) {mu}s, and the g-factor, g=-0.175(20), agree with the results of previous investigations using fusion-evaporation reactions. (orig.)

  17. Radiological characterization of the coal ash and slag from Kastel Gomilica, Croatia

    Energy Technology Data Exchange (ETDEWEB)

    Lovrencic, I.; Orescanin, V.; Barisic, D.; Mikelic, L.; Rozmaric Macefat, M.; Lulic, St. [Rudjer Boskovic Institute, Zagreb (Croatia); Pavlovic, G. [Zagreb Univ., Faculty of Science, Dept. of Mineralogy and Petrography (Croatia)

    2006-07-01

    objective of this study was radiological characterization of slag and ash produced in a thermo electric unit of the former 'Adriavinil' chemical factory as a by-product of coal combustion and deposited in the Kastel Gomilica region, Croatia. The waste material was deposited in the 'old' regulated and the 'new' unregulated part of the depot. 33 samples were analyzed to obtain a preliminary data on the present state of the new unregulated part of the depot. Activities of the selected radionuclides (40 K, 232 Th, 235 U and 226 Ra) were measured using gamma-spectrometry method. 238 U activity was calculated from the assumed natural 235 U /238 U activity ratio. It is found that there is a dependence of the activities of the selected radionuclides on the activities of the coal used for energy production in the power unit. The content of 232 Th, 226 Ra and 238 U in slag and ash increased several times during the combustion process. Investigated slag and ash showed a significant variability in their activities of selected radionuclides due to a different origin of coal used in the thermoelectric unit of the factory. The waste material was characterized by high activity of naturally occurring 238 U, 235 U and 226 Ra. 226 Ra and 238 U activities were up to 50 times higher than their average activities characteristic for surrounding soils developed on flysch sediments. 40 K and 232 Th showed no elevation compared to soil activities. Mineralogical analysis has been made as well. (authors)

  18. Pre-neutron-emission Mass Distributions for Neutron-induced 238U Fission at Low and Intermediate Energies%中低能中子诱发238U裂变的碎片质量分布

    Institute of Scientific and Technical Information of China (English)

    孙小军; 余呈刚; 王宁

    2012-01-01

    乏燃料中238U含量最多(高达95%),研究中子诱发238U裂变产物的分布特性对乏燃料的循环后处理具有非常重要的意义.本文基于微观和唯象方法的裂变势模型理论,研究入射能量从0.9 MeV-60.0 MeV能区的中子诱发238U裂变反应的发射中子前碎片质量分布,结果表明:在中能区,理论计算结果能很好地重现实验数据,甚至比国际著名的TALYS理论计算的结果要好;在低能区,理论计算结果也较为合理,并分析了与实验数据有所偏差的原因.%238Utof which abundance is almost 95% ,is one of the most important isotopes of the spent nuclear fuel. The study of neutron-induced 238U fission is in favor of the cycle processing of the spent fuel. Based on the microscopic and phenomenological approach,the pre-neutron-emission mass distributions of neutron-induced 238U fission at incident energies from 0. 9 to 60 MeV have been studied with the fission potential theory proposed in previous paper. The calculated results could well reproduce the experimental data,and are even better than that of the famous TALYS code at intermediate energies.The results can also reasonably predict the distributions at the vibrational resonances,and the deviation between the experimental and the theoretical data is also analyzed.

  19. Carbon export fluxes and export efficiency in the central Arctic during the record sea-ice minimum in 2012: a joint 234Th/238U and 210Po/210Pb study

    Science.gov (United States)

    Roca-Martí, Montserrat; Puigcorbé, Viena; Rutgers van der Loeff, Michiel M.; Katlein, Christian; Fernández-Méndez, Mar; Peeken, Ilka; Masqué, Pere

    2016-07-01

    The Arctic sea-ice extent reached a record minimum in September 2012. Sea-ice decline increases the absorption of solar energy in the Arctic Ocean, affecting primary production and the plankton community. How this will modulate the sinking of particulate organic carbon (POC) from the ocean surface remains a key question. We use the 234Th/238U and 210Po/210Pb radionuclide pairs to estimate the magnitude of the POC export fluxes in the upper ocean of the central Arctic in summer 2012, covering time scales from weeks to months. The 234Th/238U proxy reveals that POC fluxes at the base of the euphotic zone were very low (2 ± 2 mmol C m-2 d-1) in late summer. Relationships obtained between the 234Th export fluxes and the phytoplankton community suggest that prasinophytes contributed significantly to the downward fluxes, likely via incorporation into sea-ice algal aggregates and zooplankton-derived material. The magnitude of the depletion of 210Po in the upper water column over the entire study area indicates that particle export fluxes were higher before July/August than later in the season. 210Po fluxes and 210Po-derived POC fluxes correlated positively with sea-ice concentration, showing that particle sinking was greater under heavy sea-ice conditions than under partially ice-covered regions. Although the POC fluxes were low, a large fraction of primary production (>30%) was exported at the base of the euphotic zone in most of the study area during summer 2012, indicating a high export efficiency of the biological pump in the central Arctic.

  20. 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)

    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 234U/238U 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, (234U/238U) 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. 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

    2015-12-01

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

  2. 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)

  3. SOME ASPECTS OF THE INFLUENCE OF URANIUM EXPLOITATION ON THE ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Stefan DIMOVSKI

    2012-11-01

    Full Text Available Gamma-ray spectrometric measurements of samples of riverbed sediments and soil samples taken along the valley of a river, which runs very close to a uranium mine retaining dam are performed. The content of 238U, 226Ra, 210 Pb, 232Th, and 40K is analyzed. Up to a distance of about 6 km away from the retaining dam, 238U, 226Ra and 210Pb have high concentrations and the content in the sediments samples is consistently higher than the content in the soil samples. In the same interval are observed considerable fluctuations in the contents related to the swamping of the river. Receding at a greater distance from the retaining dam, the concentration of 238U, 226Ra and 210Pb decreases and has values close to the average ones. A very close correlation is established between the contents of the three radioactive nuclides. Regarding 232Th and 40K, the distribution characteristics along the profile are different in comparison with those of the 238U family members. The performed research contributes to the estimate of the radioactive contamination in a specific area situated in the vicinity of a uranium deposit exploited through underground mining.

  4. 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)

    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.)

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

    OpenAIRE

    Olszewski, Grzegorz; Boryło, Alicja; Skwarzec, Bogdan

    2015-01-01

    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 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...

  6. 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

  7. 1.4MeV-5MeV中子诱发238U裂变产额测量%Fission Product Yield Measurement of 238 U Induced by 1.4-5 MeV Neutrons

    Institute of Scientific and Technical Information of China (English)

    李映映; 肖军; 王攀; 李子越; 汪超; 罗小兵

    2016-01-01

    238 U fission yield measurement has a significant meaning in nuclear data measurement .This thesis a-dopts1.4 MeV-5 MeV mono -energetic neutrons generated by 2.5 MeV proton electrostatic accelerator to stimulate 238U fission, and then measures the yield of fission product nuclide 135I、133I、105Ru and 91Sr through measuring fission product radioactivity .Neutron flux during irradiation process is determined by activation meth-od .Subsequently , this thesis analyzes multiple components influencing experiment measurement , including cor-rection on neutron′s multiple scattering and self -shielding effect in target head and sample on the basis of MC-NPX program as well as correction on sample′s self-absorption of γ-ray.Typical deviation of yield data is concluded as 3.5%.Finally, this thesis compares measurement consequences with existing fission yield data .%238 U裂变产额测量工作在核数据测量中有着重要意义,本工作利用2.5MeV质子静电加速器产生的1.4MeV-5MeV单能中子诱发238 U裂变,通过对裂变产物放射性的测量对裂变产物核素135 I、133 I、105 Ru和91 Sr的产额进行了测定。照射过程中中子通量用活化法确定。分析了影响实验测量的多个因素,包括用MCNPX程序对中子在靶头及样品中的多次散射和自屏蔽效应进行了修正,对γ射线在样品中的自吸收进行修正等。得到产额数据典型误差为3.5%,最后把测量结果与已有的裂变产额数据进行比对。

  8. Influences of parameter uncertainties within the ICRP-66 respiratory tract model: regional tissue doses for 239PuO2 and 238UO2/238U3O8.

    Science.gov (United States)

    Farfán, Eduardo B; Huston, Thomas E; Bolch, W Emmett; Vernetson, William G; Bolch, Wesley E

    2003-04-01

    This paper extends an examination of the influence of parameter uncertainties on regional doses to respiratory tract tissues for short-ranged alpha particles using the ICRP-66 respiratory tract model. Previous papers examined uncertainties in the deposition and clearance aspects of the model. The critical parameters examined in this study included target tissue depths, thicknesses, and masses, particularly within the thoracic or lung regions of the respiratory tract. Probability density functions were assigned for the parameters based on published data. The probabilistic computer code LUDUC (Lung Dose Uncertainty Code) was used to assess regional and total lung doses from inhaled aerosols of 239PuO2 and 238UO2/238U3O8. Dose uncertainty was noted to depend on the particle aerodynamic diameter. Additionally, dose distributions were found to follow a lognormal distribution pattern. For 239PuO2 and 238UO2/238U3O8, this study showed that the uncertainty in lung dose increases by factors of approximately 50 and approximately 70 for plutonium and uranium oxides, respectively, over the particle size range from 0.1 to 20 microm. For typical exposure scenarios involving both radionuclides, the ratio of the 95% dose fractile to the 5% dose fractile ranged from approximately 8-10 (corresponding to a geometric standard deviation, or GSD, of about 1.7-2) for particle diameters of 0.1 to 1 microm. This ratio increased to about 370 for plutonium oxide (GSD approximately 4.5) and to about 600 for uranium oxide (GSD approximately 5) as the particle diameter approached 20 microm. However, thoracic tissue doses were quite low at larger particle sizes because most of the deposition occurred in the extrathoracic airways. For 239PuO2, median doses from LUDUC were found be in general agreement with those for Reference Man (via deterministic LUDEP 2.0 calculations) in the particle range of 0.1 to 5 microm. However, median doses to the basal cell nuclei of the bronchial airways (BB

  9. The cumulative effect of three decades of phosphogypsum amendments in reclaimed marsh soils from SW Spain: {sup 226}Ra, {sup 238}U and Cd contents in soils and tomato fruit

    Energy Technology Data Exchange (ETDEWEB)

    Abril, Jose-Maria [Dpto. Fisica Aplicada I, Universidad de Sevilla, EUITA, Ctra Utrera Km 1, 41013 Seville (Spain); Garcia-Tenorio, Rafael [Dpto. Fisica Aplicada II, Universidad de Sevilla, ETSA, Avda. Reina Mercedes s/n, 41012 Seville (Spain); Enamorado, Santiago M. [Dpto. Fisica Aplicada I, Universidad de Sevilla, EUITA, Ctra Utrera Km 1, 41013 Seville (Spain); Hurtado, M. Dolores; Andreu, Luis; Delgado, Antonio [Dpto. Ciencias Agroforestales, Universidad de Sevilla, EUITA, Ctra Utrera Km 1, 41013, Seville (Spain)

    2008-09-15

    Phosphogypsum (PG), a by-product of the phosphate fertiliser industries, has been applied as soil amendment to reduce Na saturation in soils, as in the reclaimed marsh area from SW Spain, where available PG has a typical fingerprint of 710 {+-} 40 Bq kg{sup -1} of {sup 226}Ra, 165 {+-} 15 Bq kg{sup -1} of {sup 238}U and 2.8 {+-} 0.4 mg kg{sup -1} of Cd. This work was focussed on the cumulative effects of PG amendments on the enrichment of these pollutants in cultivated soils and plants (Lycopersicum esculentum Mill L.) from the area studied, where PG has been applied since 1978 at recommended rates of 20-25 Mg ha{sup -1} every 2-3 years. A field experiment was conducted over three years to compare activity concentrations of {sup 226}Ra ({sup 214}Pb) and {sup 238}U ({sup 234}Th) in non-reclaimed soils, reclaimed soils with no additional PG application, and reclaimed soils with two additional PG applications. A non-significant effect of two PG amendments (in three years) was observed when compared with non-amended reclaimed plots. Nevertheless, a significant (p < 0.05) enrichment of {sup 226}Ra was observed in the surface horizon (0-30 cm) of reclaimed plots relative to deeper horizons and also when compared with the surface horizon of non-reclaimed soil (p < 0.05), thereby revealing the cumulative effect of three decades of PG applications. Furthermore, the effect of a continuous application of PG was studied by analysing soils and tomato fruits from six commercial farms with different cumulative rates of PG applied. Cadmium concentrations in tomatoes, which were one order of magnitude higher than those found in tomatoes from other areas in South Spain, were positively correlated (r = 0.917*) with {sup 226}Ra-concentration in soils, which can be considered an accurate index of the cumulative PG rate of each farm.

  10. 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.

  11. Beta and gamma decay heat measurements between 0.1s-50,000s for neutron fission of {sup 235}U, {sup 238}U and {sup 239}Pu. Progress report, March 1, 1993--January 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Schier, W.A.; Couchell, G.P.

    1994-06-01

    Decay heat measurements following the fast fission of {sup 238}U are well underway. The He-jet system and spectrometers were moved to the 1 MW research reactor to gain sufficient fast neutron flux for these measurements. On the Van de Graaff accelerator, the He-jet capillary has been shortened so that beta and gamma measurements following the thermal neutron fission of {sup 235}U could be made down to delay times near 0.1 s. Gamma-ray response functions are now well characterized for gamma energies up to 1.5 MeV for our large Nal spectrometer. Such response functions out to high energies are needed to extract energy distributions of our measured gamma spectra. The response function unfolding program, FERD-PC, has been operated successfully with trial spectra. Comparisons of individual fission products for {sup 235}U(n{sub th}f) with ENDF/B-VI at short delay times suggest several improvements to the data base particularly in production probabilities. The new data acquisition and data analysis systems have arrived and will soon be brought on line extending considerably the capabilities of our research group.

  12. 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.

  13. Neutron Resonance Parameters of 238U and the Calculated Cross Sections from the Reich-Moore Analysis of Experimental Data in the Neutron Energy Range from 0 keV to 20 keV

    Energy Technology Data Exchange (ETDEWEB)

    Derrien, H

    2005-12-05

    The neutron resonance parameters of {sup 238}U were obtained from a SAMMY analysis of high-resolution neutron transmission measurements and high-resolution capture cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA) in the years 1970-1990, and from more recent transmission and capture cross section measurements performed at the Geel Linear Accelerator (GELINA). Compared with previous evaluations, the energy range for this resonance analysis was extended from 10 to 20 keV, taking advantage of the high resolution of the most recent ORELA transmission measurements. The experimental database and the method of analysis are described in this report. The neutron transmissions and the capture cross sections calculated with the resonance parameters are compared with the experimental data. A description is given of the statistical properties of the resonance parameters and of the recommended values of the average parameters. The new evaluation results in a slight decrease of the effective capture resonance integral and improves the prediction of integral thermal benchmarks by 70 pcm to 200 pcm.

  14. Measurements of Cross Sections and Decay Properties of the Isotopes of Elements 112, 114 and 116 Produced in the Fusion Reactions $^{233,238}$U, $^{242}$Pu, and $^{248}$Cm + $^{48}$Ca

    CERN Document Server

    Oganessian, Yu T; Utyonkov, V K; Lobanov, Yu V; Abdullin, F S; Polyakov, A N; Shirokovsky, I V; Tsyganov, Yu S; Gulbekyan, G G; Bogomolov, S L; Gikal, B N; Mezentsev, A N; Iliev, S; Subbotin, V G; Sukhov, A M; Voinov, A A; Buklanov, G V; Subotic, K M; Zagrebaev, V I; Itkis, M G; Patin, J B; Moody, K J; Wild, J F; Stoyer, M A; Stoyer, N J; Shaughnessy, D A; Kenneally, J M; Wilk, P A; Lougheed, R W; Ilkaev, R I; Vesnovskii, S P

    2004-01-01

    We have studied the dependence of the production cross-sections of the isotopes $^{282,283}$112 and $^{286,287}$114 on the excitation energy of the compound nuclei $^{286}$112 and $^{290}$114. The maximum cross-section values of the \\textit{xn}-evaporation channels for the reaction $^{238}$U($^{48}$Ca, \\textit{xn})$^{286 - x}$112 were measured to be: $\\sigma _{3n}=2.5_{-1.1}^{ + 1.8} $pb and $\\sigma _{4n}=0.6_{ - 0.5}^{ + 1.6} $ pb; for the reaction $^{242}$Pu($^{48}$Ca, \\textit{xn})$^{290 - x}$114: $\\sigma _{2n}\\sim 0.5$ pb, $\\sigma _{3n}=3.6_{- 1.7}^{ + 3.4} $ pb and $\\sigma _{4n}=4.5_{ - 1.9}^{ + 3.6} $ pb. In the reaction $^{233}$U($^{48}$Ca, 2--4$n$)$^{277 - 279}$112 at $E^*=34.9\\pm $2.2 MeV we measured an upper cross-section limit of $\\sigma _{xn} \\leqslant 0.6$ pb. The observed shift of the excitation energy associated with the maximum sum evaporation residue cross section $\\sigma _{\\rm {ER}}(E^*)$ to values significantly higher than that associated with the calculated Coulomb barrier can be caused by ...

  15. Accumulation of polonium 210Po, uranium (234U and 238U and plutonium (238Pu and 239+240Pu in tissues and organs of deer Carvidae from northern Poland

    Directory of Open Access Journals (Sweden)

    Strumińska-Parulska D. I.

    2013-04-01

    Full Text Available Livers, kidneys and muscles of large herbivorous animals: roe deer (Capreolus capreolus, red deer (Cervus elaphus and fallow deer (Dama dama, collected in northern Poland, were the subject of the investigation. Polonium, uranium and plutonium activities were measured using alpha spectrometry along with relevant radiochemical procedures. The average concentrations of 210Po ranged between 0.02±0.01 Bq kg−1 ww in muscles and 7.15±0.12 Bq kg−1 ww in kidneys. The concentration of 238U ranged widely between 2.49±0.18 and 69.37±5.45 mBq kg−1 ww. The average concentrations of 239+240Pu ranged between 0.18±0.04 mBq kg−1 ww in muscle and 2.77±0.60 mBq kg−1 ww in kidneys. Statistical analysis showed that the sampling location, sex, age and species did not influence on the radioisotope activities in the analyzed samples.

  16. 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)

  17. 一维贫铀/聚乙烯交替系统中D-T中子诱发的232Th(n,γ)反应率的测定与分析%Determination of 232Th(n, γ) reaction rate induced by D-T neutrons in one-dimensional alternate depleted uranium/p olyethylene shells

    Institute of Scientific and Technical Information of China (English)

    羊奕伟; 刘荣; 蒋励; 鹿心鑫; 王玫; 严小松

    2014-01-01

    A series of neutron integral fundamental researches of thorium nuclear data in set-ups containing thorium samples is carried out. One-dimensional alternate depleted uranium/polyethylene shells containing thorium samples are constructed by referring to the conceptual design of fusion-fission hybrid reactor, where a D-T neutron source driven by accelerator is used to simulate the fusion core of the reactor. 232Th (n,γ) reaction rates in samples located at different positions in the shells are measured in 5% uncertainty by using activated thorium sample decay γ-ray off-line measurement technique. The results show that the moderation of polyethylene to 14.1 MeV neutron will efficiently increase the capture rate of thorium, and the depleted uranium is also conducible to this increase obviously. The comparison between our measured data and the results available from mainstream nuclear data bank shows that the calculation results from ENDF/B-VI.6 and JENDL-3.3 are around 6% higher than the experimental results, while the newer ENDF/B-VII.0 will achieve better results, around 4% higher than the experimental results. We recommend the ENDF/B-VII.0 to be used in one-dimensional alternate depleted uranium/polyethylene shells related conceptual design when calculating the 232Th (n,γ) reaction rate.%开展了钍样品装置内钍核参数的积分中子学基础研究.参考混合堆概念设计搭建了内部放置了钍样品的一维贫铀/聚乙烯交替系统装置,采用加速器D-T中子源模拟聚变堆芯,利用前期开发的离线伽马测量方法测定了不同位置、不同中子谱情况下的232Th (n,γ)反应率,不确定度约为5%.结果显示,聚乙烯对14.1 MeV中子的慢化作用可有效提升钍俘获率,且贫铀对钍俘获率也有显著提升作用.实验结果与主流核数据库计算结果的对比显示, ENDF/B-VI.6和JENDL-3.3数据库的计算值比实验值平均约大6%,而较新的ENDF/B-VII.0数据库的计

  18. Determination of 232Th(n, γ) reaction rate induced by D-T neutrons in one-dimensional alternate depleted uranium/p olyethylene shells%一维贫铀/聚乙烯交替系统中D-T中子诱发的232Th(n,γ)反应率的测定与分析

    Institute of Scientific and Technical Information of China (English)

    羊奕伟; 刘荣; 蒋励; 鹿心鑫; 王玫; 严小松

    2014-01-01

    A series of neutron integral fundamental researches of thorium nuclear data in set-ups containing thorium samples is carried out. One-dimensional alternate depleted uranium/polyethylene shells containing thorium samples are constructed by referring to the conceptual design of fusion-fission hybrid reactor, where a D-T neutron source driven by accelerator is used to simulate the fusion core of the reactor. 232Th (n,γ) reaction rates in samples located at different positions in the shells are measured in 5% uncertainty by using activated thorium sample decay γ-ray off-line measurement technique. The results show that the moderation of polyethylene to 14.1 MeV neutron will efficiently increase the capture rate of thorium, and the depleted uranium is also conducible to this increase obviously. The comparison between our measured data and the results available from mainstream nuclear data bank shows that the calculation results from ENDF/B-VI.6 and JENDL-3.3 are around 6% higher than the experimental results, while the newer ENDF/B-VII.0 will achieve better results, around 4% higher than the experimental results. We recommend the ENDF/B-VII.0 to be used in one-dimensional alternate depleted uranium/polyethylene shells related conceptual design when calculating the 232Th (n,γ) reaction rate.%开展了钍样品装置内钍核参数的积分中子学基础研究.参考混合堆概念设计搭建了内部放置了钍样品的一维贫铀/聚乙烯交替系统装置,采用加速器D-T中子源模拟聚变堆芯,利用前期开发的离线伽马测量方法测定了不同位置、不同中子谱情况下的232Th (n,γ)反应率,不确定度约为5%.结果显示,聚乙烯对14.1 MeV中子的慢化作用可有效提升钍俘获率,且贫铀对钍俘获率也有显著提升作用.实验结果与主流核数据库计算结果的对比显示, ENDF/B-VI.6和JENDL-3.3数据库的计算值比实验值平均约大6%,而较新的ENDF/B-VII.0数据库的计

  19. Neutron scattering studies in the actinide region

    International Nuclear Information System (INIS)

    During the report period we have investigated the following areas: Neutron elastic and inelastic scattering measurements on 14N, 181Ta, 232Th, 238U and 239Pu; Prompt fission spectra for 232Th, 235U, 238U and 239Pu; Theoretical studies of neutron scattering; Neutron filters; New detector systems; and Upgrading of neutron target assembly, data acquisition system, and accelerator/beam-line apparatus

  20. Ultra trace naturally occurring radionuclides in environmental samples by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Naturally occurring radioactive materials includes: 238 U, 235 U,234 U,232 Th and 226 Ra; which can released into the environment from many anthropogenic sources. The use of ICP-MS is well-suited instrument for a site investigations of releases of naturally occurring radioactive material through the measurements of the ratios 230 Th: 232 Th, 234 U:238 U,235 U:238 U,and 226 Ra:238U. Each measurement may potentially indicate the contrast between the geochemical background and the affected environment. The concentrations of natural uranium isotopes (238 U, 235 U and 234 U), thorium isotopes (232 Th and 230 Th) and 226 Ra, were studied in soil and plant samples collected from banks of river Nile, Egypt. Th and U are concentrated using UTEVA extraction resin. Thorium isotopic measurements were applied to studies the accumulation of 230 Th in phosphate-fertilized lawns . precision of isotope ratios are 1-8%(2σmean)

  1. 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

  2. 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.

  3. Determination of technologically enhanced naturally occurring radioactive material (TENORM) in ashes from coal-fired thermal power plants in the Philippines

    International Nuclear Information System (INIS)

    and 40K were about equallypartitioned between BA and FA samples; 238U had consistently higher partitioning in all FA samples than BA samples; 226Ra and 232Th had varied partitioning behavior among the Plants' BA and FA samples. The behavior of the radionuclides during combustion was explained to be influenced by their physical and chemical characteristics and their association with the alumino-silicate minerals in the coal. For most samples, positive correlations between NIRS ICP-MS and NIRS HPGe were very high for 226Ra with 238U (R2=0.98), and 228Ra with 232Th (R2=0.94). Correspondence between ICP-MS and HPGe results were generally high with slopes of 0.90 and zero intercept for both 226Ra vs 238U and 228Ra vs 232Th. Correlations between NIRS HPGe and PNRI HPGe were also very high for 226Ra (R2=0.93) and 228Ra (R2=0.91), and high for 40K (R2=0.86). However the slopes of the correlation lines gave only 0.65 to 0.68 correspondence of NIRS HPGe relative to PNRI HPGe. This could be attribute to the slight difference in sample and standard geometry used in PNRI HPGe experiment and different multi-channel analyzer emulation software used by NIRS and PNRI HPGe's. The result of more detailed study in Plant C showed that the ACs of 226Ra, 228Ra, and 40K were similar between two sampling periods in 2005 and 2006; the ACs in the ash pond were generally slightly lower than that in the BA and FA samples; and the ACs showed a slight decreasing trend with ash pond depth. The AC in both BA and FA samples from Plants C, M, P and S were all below the International Atomic Energy Agency (IAEA) and European Commission (EC) recommended AC levels for regulatory control. The absorbed gamma dose rates in air inside Plant C ranged from29-36 nGy/h; in its vicinity (adjacent agricultural, public and residential areas) 27-41 nGy/h; and in the pond, 44-56 Gy/h. These were within the reported dose rates in Marinduque, Batan Island, and worldwide average in UNSCEAR. Based on the AC values in FA

  4. Muon-induced fission

    International Nuclear Information System (INIS)

    A review of recent experimental results on negative-muon-induced fission, both of 238U and 232Th, is given. Some conclusions drawn by the author are concerned with muonic atoms of fission fragments and muonic atoms of the shape isomer of 238U. (author)

  5. Systematics of fission cross sections at the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Fukahori, Tokio; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    The systematics was obtained with fitting experimental data for proton induced fission cross sections of Ag, {sup 181}Ta, {sup 197}Au, {sup 206,207,208}Pb, {sup 209}Bi, {sup 232}Th, {sup 233,235,238}U, {sup 237}Np and {sup 239}Pu above 20 MeV. The low energy cross section of actinoid nuclei is omitted from systematics study, since the cross section has a complicated shape and strongly depends on characteristic of nucleus. The fission cross sections calculated by the systematics are in good agreement with experimental data. (author)

  6. 232Th、233U、238Pu、240Pu、242Pu、241Am、242Cm、243Cm和244Cm的裂变释放热能研究%Thermal Energy Released in Fission of 232 Th,233 U,238 Pu, 240 Pu,242 Pu,241 Am,242 Cm,243 Cm and 244 Cm

    Institute of Scientific and Technical Information of China (English)

    赵艳飞; 马续波; 陈义学

    2013-01-01

    In the nuclear reactor design ,the precise calculation of thermal fission energy is of great significance .In the pressurized water reactor ,high energy neutron-induced fission rarely occurs ,the isotopes including 233 U ,241 Am and 243 Cm are mostly induced by thermal neutrons ,while the other isotopes such as 232Th ,238Pu ,240Pu ,242Pu ,242Cm and 244 Cm are by fast neutron . In order to carry out this work , the nuclear data extracted from the latest evaluated nuclear data file (ENDF/B-Ⅶ ) were adopted ,and the energy-conservation law for the calculation of total fission energy were used , meanw hile ,with the consideration of capture energy and the correction of βand γ ,the thermal fission energy of nine isotopes was obtained .Compared with the data excerpted from IAEA issued WIMS-D database ,the results are reasonable .The thermal fission energy and its uncertainties of the nine isotopes are :(193.939 ± 0.176) MeV for 232 Th , (200.063 ± 0.084) MeV for 233 U ,(208.786 ± 1.133 ) MeV for 238 Pu ,(211.266 ± 0.220 ) MeV for 240 Pu ,(213.862 ± 0.299 ) MeV for 242 Pu ,(215.077 ± 0.210 ) MeV for 241 Am ,(218.821 ± 0.159) MeV for 242Cm ,(218.525 ± 0.388) MeV for 243Cm ,and (220.067 ± 0.131) MeV for 244 Cm ,respectively .%在核反应堆设计中,对每次裂变释放热能进行精确计算具有重要意义。在压水堆内,高能中子诱发核裂变份额很小,233 U、241 Am、243 Cm主要由热中子诱发裂变,232 T h、238 Pu、240 Pu、242 Pu、242 Cm、244 Cm主要由快中子诱发裂变。本文采用最新的核评价数据库 ENDF/B-Ⅶ,利用质量守恒法计算裂变释放总能,同时研究了中微子带走的能量,中子俘获能及β、γ修正项,最终给出了9种核素裂变释放热能。与IAEA颁布的WIMS-D格式数据库中的裂变释放热能数据的对比表明,本文所用方法计算结果合理。9种核素每次裂变释放热能分别为:232 Th ,(193.939±0.176) MeV ;233 U ,(200.063

  7. Measurements of cross sections and decay properties of the isotopes of elements 112, 114, and 116 produced in the fusion reactions 233,238U, 242Pu, and 248Cm+48Ca

    International Nuclear Information System (INIS)

    We have studied the dependence of the production cross sections of the isotopes 282,283112 and 286,287114 on the excitation energy of the compound nuclei 286112 and 290114. The maximum cross section values of the xn-evaporation channels for the reaction 238U(48Ca,xn)286-x112 were measured to be σ3n=2.5-1.1+1.8 pb and σ4n=0.6-0.5+1.6 pb; for the reaction 242Pu(48Ca,xn)290-x114: σ2n∼0.5 pb, σ3n=3.6-1.7+3.4 pb, and σ4n=4.5-1.9+3.6 pb. In the reaction 233U(48Ca,2-4n)277-279112 at E*=34.9=2.2 MeV we measured an upper cross section limit of σxn≤0.6 pb. The observed shift of the excitation energy associated with the maximum sum evaporation residue cross section σER(E*) to values significantly higher than that associated with the calculated Coulomb barrier can be caused by the orientation of the deformed target nucleus in the entrance channel of the reaction. An increase of σER in the reactions of actinide targets with 48Ca is consistent with the expected increase of the survivability of the excited compound nucleus upon closer approach to the closed neutron shell N=184. In the present work we detected 33 decay chains arising in the decay of the known nuclei 282112, 283112, 286114, 287114, and 288114. In the decay of 287114(α)→283112(α)→279110(SF), in two cases out of 22, we observed decay chains of four and five sequential α transitions that end in spontaneous fission of 271Sg (Tα/SF=2.4-1.0+4.3 min) and 267Rf (TSF∼2.3 h), longer decay chains than reported previously. We observed the new nuclide 292116 (Tα=18-6+16 ms,Eα=10.66±0.07 MeV) in the irradiation of the 248Cm target at a higher energy than in previous experiments. The observed nuclear decay properties of the nuclides with Z=104-118 are compared with theoretical nuclear mass calculations and the systematic trends of spontaneous fission properties. As a whole, they give a consistent pattern of decay of the 18 even-Z neutron-rich nuclides with Z=104-118 and N=163-177. The experiments were

  8. On the Radiological Character of a Coal-Fired Power Plant at the Town of Çatalağzı, Turkey

    OpenAIRE

    BALDIK, Hüseyin AYTEKIN and Rıdvan

    2008-01-01

    This paper presents a study performed on the radiological character of the Çatalağzı Thermal Power Plant (ÇTPP/ÇATES), on the west Black Sea coast of Turkey. Natural radioactivity distribution of the terrestrial radionuclides 238U, 232Th, and 40K of surface soil samples around the ÇTPP was analyzed. The average radioactivity concentrations for 232Th, 238U, and 40K for soil samples were 39.7, 30.5, and 378.7 Bq kg-1, respectively. 238U and 40K concentrations are lower than the world ...

  9. Factors Controlling the Groundwater Transport of U, Th, Ra, and Rn

    Indian Academy of Sciences (India)

    A Tricca; D Porcelli; G J Wasserburg

    2000-03-01

    A model for the groundwater transport of naturally occurring U, Th, Ra, and Rn nuclides in the 238U and 232Th decay series is discussed. The model developed here takes into account transport by advection and the physico-chemical processes of weathering, decay, -recoil, and sorption at the water-rock interface. It describes the evolution along a flowline of the activities of the 238U and 232Th decay series nuclides in groundwater. Simple sets of relationships governing the activities of the various species in solution are derived, and these can be used both to calculate effective retardation factors and to interpret groundwater data. For the activities of each nuclide, a general solution to the transport equation has been obtained, which shows that the activities reach a constant value after a distance $\\bar{x}_i$, characteristic of each nuclide. Where $\\bar{x}_i$ is much longer than the aquifer length, (for 238U, 234U, and 232Th), the activities grow linearly with distance. Where $\\bar{x}_i$ is short compared to the aquifer length, (for 234Th, 230Th, 228Th, 228Ra, and 224Ra), the activities rapidly reach a constant or quasi-constant activity value. For 226Ra and 222Rn, the limiting activity is reached after 1 km. High 234U values (proportional to the ratio 234Th/W238U) can be obtained through high recoil fraction and/or low weathering rates. The activity ratios 230Th/232Th, 228Ra/226Ra and 224Ra/226Ra have been considered in the cases where either weathering or recoil is the predominant process of input from the mineral grain. Typical values for weathering rates and recoil fractions for a sandy aquifer indicate that recoil is the dominant process for Th isotopic ratios in the water. Measured data for Ra isotope activity ratios indicate that recoil is the process generally controlling the Ra isotopic composition in water. Higher isotopic ratios can be explained by different desorption kinetics of Ra. However, the model does not provide an explanation for 228Ra

  10. Natural radioactivity measurements in the granite rock of quarry sites, Johor, Malaysia

    Science.gov (United States)

    Alnour, I. A.; Wagiran, H.; Ibrahim, N.; Laili, Z.; Omar, M.; Hamzah, S.; Idi, Bello. Y.

    2012-12-01

    This study was conducted to determine the concentration of natural radionuclides in the granite rocks of selected quarry sites in Johor state, Malaysia and their possible radiological effects. The activity concentrations of 238U, 232Th and 40K in the areas of study indicated varying values of 238U, 232Th and 40K. The highest values of 238U and 232Th concentrations (67±1 and 85±2 Bq kg-1, respectively) were observed at Kamad Quarry (IJM), whereas the highest value of 40K concentration (722±18 Bq kg-1) was detected in Kim Seng Quarry, while the values of activity concentration are lower in Hanson Quarry Products (Kulai) (25±0.5 for 238U, 24±0.5 for 232Th and 429±11 for 40K). Overall, 40K has the highest concentration in the granite rocks of the quarry sites, followed by 232Th and the least for 238U. The radium equivalent activity concentration was found in the range between 94 and 239 Bq kg-1, the absorbed dose rate was found to be in the range between 47 and 112 nGy h-1, and effective dose ranged from 58 to 137 μSv h-1. Moreover, the internal and external hazard index values were given in results lower than unity.

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

    Science.gov (United States)

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

    2015-11-01

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

  12. Vertical distribution of natural radionuclides in soil: Assessment of external exposure of population in cultivated and undisturbed areas

    Energy Technology Data Exchange (ETDEWEB)

    Nenadovic, Snezana [Laboratory for Material Science, Institute of Nuclear Sciences ' Vinca' , University of Belgrade, Belgrade (Serbia); Nenadovic, Milos [Laboratory for Atomic Physics, Institute of Nuclear Sciences ' Vinca' , University of Belgrade, Belgrade (Serbia); Kljajevic, Ljiljana, E-mail: ljiljana@vinca.rs [Laboratory for Material Science, Institute of Nuclear Sciences ' Vinca' , University of Belgrade, Belgrade (Serbia); Vukanac, Ivana [Laboratory for Nuclear and Plasma Physics, Institute of Nuclear Sciences ' Vinca' , University of Belgrade, Belgrade (Serbia); Poznanovic, Maja [Geological Institute of Serbia, Chemical laboratory, University of Belgrade, Belgrade (Serbia); Mihajlovic-Radosavljevic, Ana [Laboratory for Material Science, Institute of Nuclear Sciences ' Vinca' , University of Belgrade, Belgrade (Serbia); Pavlovic, Vladimir [Faculty of Agriculture, University of Belgrade, Belgrade (Serbia)

    2012-07-01

    In the present work, naturally occurring radionuclides {sup 238}U, {sup 232}Th and {sup 40}K were measured in soil samples from the cultivated and undisturbed areas in Rudovci, municipality of Lazarevac, Serbia. There were three profiles, each profile divided into four horizons, giving the twelve soil samples. The specific activity of {sup 238}U, {sup 232}Th and {sup 40}K in soil and sediment samples was determined by gamma spectrometry using the HPGe semiconductor detector. Obtained activity concentrations ranged from 28.0 to 44.0 Bq/kg for {sup 238}U, from 59.4 to 71.4 Bq/kg for {sup 232}Th and from 335.0 to 517.0 Bq/kg for {sup 40}K. The evaluation of the radiological hazards originated from {sup 238}U, {sup 232}Th and {sup 40}K in the samples, the absorbed dose rate (D) and the annual effective dose rate (E), calculated in accordance with the UNSCEAR 2000 report, are presented in this paper. - Highlights: Black-Right-Pointing-Pointer Radionuclides {sup 238}U, {sup 232}Th and {sup 40}K in different profile of soil are measured. Black-Right-Pointing-Pointer Gamma spectrometry specific activity of radionuclides was determined. Black-Right-Pointing-Pointer Correlation between the physical-chemical parameters of soil and natural radionuclides is important. Black-Right-Pointing-Pointer Concentrations of radionuclides are not extremely changed at the profiles.

  13. Assessment of natural radioactivity in silt samples from Moticher lake near Kakrapar Atomic Power Station, India

    International Nuclear Information System (INIS)

    The naturally occurring radioisotopes such as 238U, 232Th and 40K in the silt samples collected from Moticher lake, Gujarat were evaluated. The activity of 238U, 232Th and 40K was found to be 4.4-9.7 Bq kg-1 with a mean 6.4 ± 1.3 Bq kg-1, 10.5-21.2 Bq kg-1 with a mean 15.6 ± 2.5 Bq kg-1 and 102-231 Bq kg-1 with a mean 160 ± 40 Bq kg-1, respectively. The depth profile study could not reveal any significant vertical correlation on radioactivity levels of 238U, 232Th and 40K. Radium equivalent activity (Raeq), external hazard index (Hex) and internal hazard index (Hint) were calculated by using the activity of 238U or 226Ra, 232Th and 40K in silt samples. Annual Effective Dose Equivalent (AEDE) level in Moticher silt was found to be 24.8 ± 5.0 μSv year-1, which is much lower than the worldwide average value. The relative contribution to dose due to 238U and 232Th series were found to be 14% and 53%, followed by the contribution of 33% due to 40K. (author)

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

    Science.gov (United States)

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

    2015-11-01

    The naturally occurring radionuclides of (235)U, (238)U and (232)Th and their daughter products are a potential major source of anthropogenic radiation to tobacco smokers. Often overlooked is the presence of (40)K in tobacco and its implication to radiation dose accumulation in the human body. In this study, these three radiation sources have been determined in four typical US cigarettes using neutron activation analysis (NAA). The NAA reactions of (238)U(n,γ)(239)U, (232)Th(n,γ)(233)Th and (41)K(n,γ)(42)K were used to determine (235)U, (238)U and (232)Th and (40)K, respectively. The activity of (238)U can easily be determined by epithermal NAA of the (238)U(n,γ)(239)U reaction, and the activity of (235, 234)U can easily be deduced. Using isotopic ratios, the activity due to (40)K was found by the determined concentrations of (41)K (also by epithermal neutrons) in the bulk material. Each gram of total potassium yields 30 Bq of (40)K. The annual effective dose for smokers using 20 cigarettes per day was calculate to be 14.6, 137 and 9 μSv y(-1) for (238,235,) (234)U, (232)Th and (40)K, respectively. These values are significantly lower that the dose received from (210)Po except for (232)Th. PMID:25944955

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

    International Nuclear Information System (INIS)

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

  16. Light-particle emission from the fissioning nuclei sup 1 sup 2 sup 6 Ba, sup 1 sup 8 sup 8 Pt and sup 2 sup 6 sup 6 sup , sup 2 sup 7 sup 2 sup , sup 2 sup 7 sup 8 110: theoretical predictions and experimental results 24.75.+i; 25.85.-w; 25.60.Pj; 25.70.-z; Nuclear reactions 98Mo(28Si ,X) , E=166,187,204 MeV; 107Ag(19F ,X) , E=128,148 MeV; 154Sm(34S ,X) , E=160,203 MeV; 172Yb(16O ,X) , E=138 MeV; 208Pb(58Ni ,X) , (64Ni ,X) , 232Th(40Ca ,X) , 238U(40Ar ,X) , E=66 -186 MeV; Calculated fusion, fission sigma(L) , prefission particle multiplicities; Deduced entrance channel effects; Comparisons with data

    CERN Document Server

    Pomorski, K; Surowiec, A; Kowal, M; Bartel, J; Dietrich, K G; Richert, J; Schmitt, C; Benoit, B; De Goes-Brennard, E; Donadille, L; Badimon, C

    2000-01-01

    We present a comparison of our model treating fission dynamics in conjunction with light-particle ( n,p,alpha ) evaporation with the available experimental data for the nuclei sup 1 sup 2 sup 6 Ba, sup 1 sup 8 sup 8 Pt and three isotopes of the element Z=110 . The dynamics of the symmetric fission process is described through the solution of a classical Langevin equation for a single collective variable characterizing the nuclear deformation along the fission path. A microscopic approach is used to evaluate the emission rates for prefission light particles. Entrance-channel effects are taken into account by generating an initial spin distribution of the compound nucleus formed by the fusion of two deformed nuclei with different relative orientations.

  17. U and Th series disequilibrium in unaltered and hydrothermally-altered granites from the El Berrocal site (Spain): weathering effects

    International Nuclear Information System (INIS)

    Within the framework of analysis of the safety assessment of high level radioactive waste repositories the migration of natural radionuclides in a fissured granitic environment, the El Berrocal site, is being studied in Spain. In order to determine the weathering effects on the natural radionuclides of the site, the top parts of the 238U and 232Th decay series have been measured in bulk samples of unaltered and differently altered granites by α-particle spectrometry. The results have established the recent geochemical processes involving 238U, 234U, 230Th, 232Th and 228Th such as: 234Th recoil loss, bulk U assimilation or 234U recoil gain, equilibrium states, bulk U leaching without fractionation, bulk uranium assimilation with activity ratio near unity, and loss or gain of 228Ra (228Th) as a function of the hydrochemical characteristics of the percolating water. These results have been interpreted in terms of the different degrees of weathering according to literature data. (author)

  18. A Lane consistent optical model potential for nucleon scattering on actinide nuclei with extended coupling

    Directory of Open Access Journals (Sweden)

    Quesada José Manuel

    2016-01-01

    Full Text Available An extension for odd-A actinides of a previously derived dispersive coupledchannel optical model potential (OMP for 238U and 232Th nuclei is presented. It is used to fit simultaneously all the available experimental databases including neutron strength functions for nucleon scattering on 232Th, 233,235,238U and 239Pu nuclei. Quasi-elastic (p,n scattering data on 232Th and 238U to the isobaric analogue states of the target nucleus are also used to constrain the isovector part of the optical potential. For even-even (odd actinides almost all low-lying collective levels below 1 MeV (0.5 MeV of excitation energy are coupled. OMP parameters show a smooth energy dependence and energy independent geometry.

  19. Physical-property study on liquid fluoride-salt-cooled high temperature reactor loaded with different kinds of fuel mixtures

    International Nuclear Information System (INIS)

    Background: Liquid fluoride-salt-cooled high temperature reactor, one of the GEN-IV reactors, has great advantages comparatively, and the research on its fuel is of great significance. Purpose: The aim is to study the physical properties of high-temperature pebble-bed reactors loaded with six different fuel mixtures. Methods: We used SCALE5.1 package to compute some important parameters like excess reactivity, full power operation days, burnup and neutron spectrum. Results: The results show that the true conversions of 232Th are much less than those of 238U when mixed with 233U or 235U. With 239Pu for starting, 232Th contributes to making the reactor running longer than that with 238U. Conclusion: With respect to saving fuel and extending the life of the core, without online refueling and reprocessing, 232Th is under performed in thermal reactor compared with 238U, however, it is the opposite in epithermal neutron reactor. (authors)

  20. A Lane consistent optical model potential for nucleon scattering on actinide nuclei with extended coupling

    Science.gov (United States)

    Quesada, José Manuel; Capote, Roberto; Soukhovitski, Efrem S.; Chiba, Satoshi

    2016-03-01

    An extension for odd-A actinides of a previously derived dispersive coupledchannel optical model potential (OMP) for 238U and 232Th nuclei is presented. It is used to fit simultaneously all the available experimental databases including neutron strength functions for nucleon scattering on 232Th, 233,235,238U and 239Pu nuclei. Quasi-elastic (p,n) scattering data on 232Th and 238U to the isobaric analogue states of the target nucleus are also used to constrain the isovector part of the optical potential. For even-even (odd) actinides almost all low-lying collective levels below 1 MeV (0.5 MeV) of excitation energy are coupled. OMP parameters show a smooth energy dependence and energy independent geometry.

  1. Systematic study of anomalous fragment anisotropies in subbarrier complete fusion—fission reactions

    Institute of Scientific and Technical Information of China (English)

    ZhangHuan-Qiao; LiuZu-Hua; 等

    1997-01-01

    The complete fusion-fission is separated from the transter-induced-fission with the fragment folding angle technique.The cross sections and fragment angular distributions for the complete fusion-fission reactions of 11B+ 238U(237Np),237NP,16O+232Th(238U) and 19F+232Th at near-and sub-barrier energies have been measured.The present fusion and fission standard models can reproduces both the excitation functions and the fragment anisotropies for the systems of 11B+238U(237Np)and 12C+237Np;but fail to explain both the experimental data for the other 3 systems simultaneously,The evidence of the entrance-channel dependence of fission-fragment anisotropies is revealsed by comparison of the 11B+237NP and 16O+232Th data.Based on the observations a new version model of preequilibrium fission is put forward to explain the anomaly.

  2. Standard practice for alternate actinide calibration for inductively coupled plasma-mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This practice provides guidance for an alternate linear calibration for the determination of selected actinide isotopes in appropriately prepared aqueous solutions by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). This alternate calibration is mass bias adjusted using thorium-232 (232Th) and uranium-238 (238U) standards. One of the benefits of this standard practice is the ability to calibrate for the analysis of highly radioactive actinides using calibration standards at much lower specific activities. Environmental laboratories may find this standard practice useful if facilities are not available to handle the highly radioactive standards of the individual actinides of interest. 1.2 The instrument response for a series of determinations of known concentration of 232Th and 238U defines the mass versus response relationship. For each standard concentration, the slope of the line defined by 232Th and 238U is used to derive linear calibration curves for each mass of interest using interference equ...

  3. studies on the characteristics of the TE-NORM Wastes produced from different oil and natural Gas resources

    International Nuclear Information System (INIS)

    industrial as well as technical activities disturb environmental radioactivities, especially naturally occurring radioactive materials (Norm) with subsequent concentration in their radiation hazardous . in oil and natural gas industry in egypt, the sediments, scale and / or sludge as well as waste water produced from drilling activity in many sites, were found to contain increased amounts of uranium, thorium and radium, that represent radiation hazardous to surroundings. these materials are known as: technically enhanced-naturally occurring radioactive materials (Te-Norm). in this study, the Te-Norm wastes were characterized in terms of mineralogical, chemical and radiological analysis. this study indicated that, sediments of Te-Norm wastes are commonly mixtures of sulphate, carbonate and/or silicate of the primordial nuclides 238U, 232Th and 40K and some other elements . the activity levels of 226 Ra,228Ra,224Ra and 40K were found in the ranges 11600-33200, 4200-10400, 3900-11200 and 960-11300 Bq/Kg (dry weight). respectively, for the Te-Norm waste samples produced from gabal el zeit region onshore of suez gulf (eastern desert). in waste water samples, the activity levels were found 1222,770,770 and 520 Bq/I for 226 Ra,228Ra,224Ra and 40 K, respectively. while, in case of the Te-Norm waste samples taken from badr el din region (western desert), the activity levels were found in the ranges 28400-119400, 39000-193000, 28300-166600 and 2800-15600 Bq/kg for 226Ra, 228Ra, 224Ra and 40K, respectively. the parent/daughter ratio were also estimated and discussed in the different Te-Norm waste samples

  4. Solubility of uranium and thorium from a healing earth in synthetic gut fluids: a case study for use in dose assessments.

    Science.gov (United States)

    Höllriegl, Vera; Li, Wei Bo; Leopold, Karsten; Gerstmann, Udo; Oeh, Uwe

    2010-11-01

    The aim of this case study was to estimate the bioaccessibility of uranium ((238)U) and thorium ((232)Th) from a healing earth by analysing the solubility of these radionuclides in synthetic gastric and intestinal fluids. An easy applicable in vitro test system was used to investigate the fractional mobilization of the soil contaminants being potentially available for absorption under human in vivo conditions. These findings provided the basis for a prospective dose assessment. The solubility experiments were performed using two different in vitro digestion methods. The concentrations of (238)U and (232)Th in the solutions extracted from the soil were measured by inductively coupled plasma mass spectrometry (ICP-MS). The dissolved fractions in the synthetic gastrointestinal fluid ranged in average from 10.3% to 13.8% for (238)U and from 0.3% to 1.6% for (232)Th, respectively, depending on the digestion method. Subsequently, the committed effective doses from intake of (238)U and (232)Th after ingestion of the healing earth during 1 year were evaluated for adult persons. Thereby ingestion dose coefficients calculated as a function of bioaccessibility were used. The dose assessments ranged between 4.3 × 10(-7)-1.9 × 10(-6) Sv y(-1) for (238)U and 5.6 × 10(-7)-3.3 × 10(-6) Sv y(-1) for (232)Th, respectively. On the basis of the assumptions and estimations made, the present work indicates a relatively low radiation risk due to (238)U and (232)Th after internal exposure of the healing earth.

  5. Solubility of uranium and thorium from a healing earth in synthetic gut fluids: A case study for use in dose assessments

    International Nuclear Information System (INIS)

    The aim of this case study was to estimate the bioaccessibility of uranium (238U) and thorium (232Th) from a healing earth by analysing the solubility of these radionuclides in synthetic gastric and intestinal fluids. An easy applicable in vitro test system was used to investigate the fractional mobilization of the soil contaminants being potentially available for absorption under human in vivo conditions. These findings provided the basis for a prospective dose assessment. The solubility experiments were performed using two different in vitro digestion methods. The concentrations of 238U and 232Th in the solutions extracted from the soil were measured by inductively coupled plasma mass spectrometry (ICP-MS). The dissolved fractions in the synthetic gastrointestinal fluid ranged in average from 10.3% to 13.8% for 238U and from 0.3% to 1.6% for 232Th, respectively, depending on the digestion method. Subsequently, the committed effective doses from intake of 238U and 232Th after ingestion of the healing earth during 1 year were evaluated for adult persons. Thereby ingestion dose coefficients calculated as a function of bioaccessibility were used. The dose assessments ranged between 4.3 x 10-7-1.9 x 10-6 Sv y-1 for 238U and 5.6 x 10-7-3.3 x 10-6 Sv y-1 for 232Th, respectively. On the basis of the assumptions and estimations made, the present work indicates a relatively low radiation risk due to 238U and 232Th after internal exposure of the healing earth.

  6. Solubility of uranium and thorium from a healing earth in synthetic gut fluids: a case study for use in dose assessments.

    Science.gov (United States)

    Höllriegl, Vera; Li, Wei Bo; Leopold, Karsten; Gerstmann, Udo; Oeh, Uwe

    2010-11-01

    The aim of this case study was to estimate the bioaccessibility of uranium ((238)U) and thorium ((232)Th) from a healing earth by analysing the solubility of these radionuclides in synthetic gastric and intestinal fluids. An easy applicable in vitro test system was used to investigate the fractional mobilization of the soil contaminants being potentially available for absorption under human in vivo conditions. These findings provided the basis for a prospective dose assessment. The solubility experiments were performed using two different in vitro digestion methods. The concentrations of (238)U and (232)Th in the solutions extracted from the soil were measured by inductively coupled plasma mass spectrometry (ICP-MS). The dissolved fractions in the synthetic gastrointestinal fluid ranged in average from 10.3% to 13.8% for (238)U and from 0.3% to 1.6% for (232)Th, respectively, depending on the digestion method. Subsequently, the committed effective doses from intake of (238)U and (232)Th after ingestion of the healing earth during 1 year were evaluated for adult persons. Thereby ingestion dose coefficients calculated as a function of bioaccessibility were used. The dose assessments ranged between 4.3 × 10(-7)-1.9 × 10(-6) Sv y(-1) for (238)U and 5.6 × 10(-7)-3.3 × 10(-6) Sv y(-1) for (232)Th, respectively. On the basis of the assumptions and estimations made, the present work indicates a relatively low radiation risk due to (238)U and (232)Th after internal exposure of the healing earth. PMID:20832099

  7. The assessment of natural radioactivity and its associated radiological hazards and dose parameters in granite samples from South Sinai, Egypt

    OpenAIRE

    D.A.E. Darwish; K.T.M. Abul-Nasr; A.M. El-Khayatt

    2015-01-01

    Gamma ray spectra of natural radioactivity from 238U- and 232Th series and from 40K of eight (representing 40 collected samples) granite samples collected from Saint Katherine region, South Sinai, Egypt, had been measured using a gamma-ray spectrometer with an HPGe detector. The results reported in the present article include: Specific activities (A) of 226Ra, 232Th and 40K radionuclides, Radium equivalent activities (Raeq), external and internal hazard indices (Hext, Hint), external and inte...

  8. Rapid analysis technique for strontium, thorium, and uranium in urine samples

    International Nuclear Information System (INIS)

    Rapid analysis for 90Sr, 232Th, and 238U in human urine samples collected in a radiation emergency can be developed by co-precipitation with calcium phosphate and separation using a Sr-resin (Eichrom Technologies, Inc.) column. The nuclides were measured by inductively coupled plasma mass spectrometry (ICP-MS) or a low background β-counter. Spike tests yielded a good recovery of above 90%. Fractions of 90Sr and the other nuclides (232Th and 238U) were separated in about 2 hours. It was judged that the developed method would be an effective bioassay method in radiation emergency. (author)

  9. Measurement of natural and 137Cs radioactivity concentrations at Izmit Bay (Marmara Sea), Turkey

    Science.gov (United States)

    Öksüz, I.; Güray, R. T.; Özkan, N.; Yalçin, C.; Ergül, H. A.; Aksan, S.

    2016-03-01

    In order to determine the radioactivity level at Izmit Bay Marmara Sea, marine sediment samples were collected from five different locations. The radioactivity concentrations of naturally occurring 238U, 232Th and 40K isotopes and also that of an artificial isotope 137Cs were measured by using gamma-ray spectroscopy. Preliminary results show that the radioactivity concentrations of 238U and 232Th isotopes are lower than the average worldwide values while the radioactivity concentrations of the 40K are higher than the average worldwide value. A small amount of 137Cs contamination, which might be caused by the Chernobyl accident, was also detected.

  10. Concentration measurements of uranium, thorium and their daughter products in water produced from and near oil fields in north of Iraq using SSNTRD's passive method

    International Nuclear Information System (INIS)

    The radioactivity concentrations of 238U, 232Th and their daughter products in water samples collected from different oil fields and sources in north of Iraq, were determined by using CR-39 and LR-115 SSNTRDs. It was found that the concentrations of 238U and 232Th vary between 0.20 and 3.50 ppm and from 0.03 to 1.83 ppm, respectively. According to the recommended values and the calculated annual effective dose, most of the produced water from the studied oil fields is not useful for any direct purpose. (author)

  11. Determination of natural radioactivity levels in Kars- city center, Turkey

    OpenAIRE

    B., CENGİZ G.; REŞİTOĞLU,; De, S.

    2014-01-01

    The objective of this study is to determine the distribution of natural radionuclides in surface soils in the Karscity center, Turkey. The activity concentrations of 238U, 232 Th, 40 K and 137Cs in 38 soil samples collected from the study area were measured through NaI(Tl) gamma spectrometry. The average activities of the samples were determined to be 47.8, 31.2 and 536 Bqkg-1 for the natural radionuclides 226Ra (238U), 232Th, 40K, respectively, and 18 Bqkg-1 for the fission product 137Cs. ...

  12. Correlations of natural radionuclides in soil with those in sediment from the Danube and nearby irrigation channels

    International Nuclear Information System (INIS)

    The correlation between activity concentrations of some natural radionuclides (238U, 226Ra, 232Th, 40K) measured in soil and in sediment taken from the Danube River and nearby irrigation channels was studied. The soil samples were collected from the northern part of Serbia and the sediment from the Serbian part of the Danube River and from the surrounding irrigation channels. The correlation between 238U and other natural radionuclides in irrigation channel sediments was not as good as in the Danube. One of the possible explanations for this weak correlation can be the different chemical dynamics of 238U in the irrigation channel sediment or changes of the 238U activity concentration in irrigation channel sediment due to some human activities. The evaluation of ratios of activity concentrations of some natural radionuclides could be a more sensitive method for the determination of contaminant, rather than the straightforward analysis of activity concentrations. -- Highlights: ► 238U, 232Th and 40K were measured in soil, Danube and surrounding channel sediment. ► Correlation of activity concentrations were observed. ► In cannel sediment natural radionuclides are not well correlated as in Danube one. ► Ratios of 238U, 232Th and 40K can be good indicator for TENORM monitoring

  13. Implantation of alpha spectrometry methodology for the determination of U and Th isotopes in igneous rocks: application to the study of radioactive desequilibrium in the Trindade Island, Brazil

    International Nuclear Information System (INIS)

    This work describes the implementation of experimental procedures for alpha spectrometry measurement of 238U, 234U and 230Th activities in silicates. The best experimental conditions were defined using 233U, 232U and 229Th radioactive tracers and simulating the usual conditions found in processing silicates. The chemical procedures consists of the following steps: radioactive tracer addition and sample dissolution by acid digestion, U and Th pre-concentration by co-precipitation, element separation and purification by ion exchange chromatography and electrodeposition in inox steel disks. In order to evaluate its effectiveness, the procedure was applied to the Brazilian geological standards BB-1 (basalt) and GB-1 (granite). The obtained chemical yields for uranium and thorium are of about 60% and 70%, respectively, for both matrices. The described methodology furnishes activity measurements with less than 4% relative precision and accuracies of about 1%, that are essential for petrogenetic applications. The 238U and 232Th series disequilibrium conditions were investigated by alpha spectrometry, together with neutron activation analysis and natural gamma-ray spectrometry. 234U/238U, 238U/232Th and 230Th/232Th activity ratios and the 234Th, 214Pb, 214Bi, 235U, 228Ac, 212Pb, 212Bi and 208Tl specific activities were obtained. These results were interpreted with the help of additional constraints given by the larger and smaller elements concentrations, measured by X-ray fluorescence. The 232Th series is in secular radioactive equilibrium in all analysed samples. In the case of the 238U series, the equilibrium condition was verified, as expected, in the oldest rocks from the Trindade Island (Trindade Complex and Desejado Sequence). On the other hand, the results show that, in the samples from the last three volcanic episodes in the island (Morro Vermelho Formation, Valado Formation and Vulcao do Paredao), the 230Th and 238U are not in equilibrium. Furthermore the three

  14. Spatial and depth wise characterization of radionuclides and minerals in various beach sediments from high background radiation area, Kerala, India

    International Nuclear Information System (INIS)

    The activity concentrations (238U, 232Th and 40K) and mineralogical characterization of different layer (upper surface, first, second and third feet) Kerala beach sediments have been assessed with an aim of evaluating the radioactivity content profile, its relation to specific minerals and their distributions (spatial and depth wise). The eight different radiological indices are calculated for all samples and compared with either recommended values or the world average values of radioactivity content of the three primordial radionuclides to assess the complete radiological profile of the sediments. The radioactivity study suggests that the average specific activities of radionuclides (238U and 232Th) are higher than the world average values as given in UNSCEAR reports and all radiological parameters in all layer samples are more than the recommended safety levels. These results are on the expected lines since the samples are from a well-known high background radiation area. Using FTIR, mineralogical characteristics of the sediments were analyzed and the extinction coefficient is calculated to find the relative distribution of major minerals. The calculated values show that the amount of major minerals decreases in the order of quartz>calcite>kaolinite>microcline feldspar in all layers. To confirm the results obtained from FTIR, XRD analysis was also carried out. The observations made through the XRD technique are matched with FTIR observations. Statistical analyses (cluster and factor analysis) are carried out to assess the relation between the radionuclides and minerals, and also assess their distribution patterns in different layers. The analyses suggest that the concentration of 40K may have a strong association with the light mineral calcite and also suggest that spatial distributions of 40K and calcite are almost similar in every layer. The concentrations of 238U, 232Th and absorbed dose rate are evenly distributed (spatial) and other variables are randomly

  15. A novel assay method for the trace determination of Th and U in copper and lead using inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    LaFerriere, B.D.; Maiti, T.C.; Arnquist, I.J.; Hoppe, E.W., E-mail: eric.hoppe@pnnl.gov

    2015-03-01

    This study describes a novel sample preparation and assay method developed, primarily in support of the MAJORANA DEMONSTRATOR neutrinoless double-beta decay experiment, for the determination of extremely low levels of Th and U in copper and lead shielding components. Meticulously clean sample preparation methods combined with anion exchange separations for analyte pre-concentration and matrix removal were developed. Quantification was performed by isotope dilution inductively coupled plasma mass spectrometry. Detection limits of 0.0084 pg {sup 232}Th/g (0.034 µBq {sup 232}Th/kg) and 0.0106 pg {sup 238}U/g (0.131 µBq {sup 238}U/kg) were determined for copper, while detection limits of 0.23 pg {sup 232}Th/g (0.94 µBq {sup 232}Th/kg) and 0.46 pg {sup 238}U/g (5.7 µBq {sup 238}U/kg) were achieved for lead. These methods allow the Majorana Collaboration to accurately assay detector components and ensure that the experiment's stringent radiopurity requirements are met.

  16. The ultra-pure Ti for the low background experiments

    Science.gov (United States)

    Chepurnov, Alexander; Nisi, Stefano; di Vacri, Maria Laura; Suvorov, Yury

    2013-08-01

    The constant increase in mass of the cryostats, containment tanks, passive shielding and other mechanical elements of the modern low background detectors put more stringent requirements on their radiopurity levels. In general they have to be ˜1 mBq/kg of 238U/232Th or lower, which means that mass concentration should be manufactory line.

  17. Decision making algorithm of the rehabilitation of agricultural lands contaminated with heavy natural radionuclides

    International Nuclear Information System (INIS)

    Problem of rehabilitation of agricultural land contaminated with heavy natural radionuclides (210Pb,210Po,226Ra,232Th,238U) was considered. Algorithm of decision making support on advisability of rehabilitation of mentioned land was suggested. Proposed algorithm was tested on the base of agricultural farmlands located in the affected zone of Pridneprovsky Chemicals Plant and its tailing dumps

  18. Activity levels of some radionuclides in Mariout and Brullus lakes, Egypt.

    Science.gov (United States)

    Dar, Mahmoud A; El Saharty, Abeer A

    2013-11-01

    Mariout and Brullus are two of the highly fish-productive lakes in the northern coast of Egypt along the Mediterranean Sea. They are widely used to drain industrial wastes, sewage and agriculture drainage. The activities of (238)U, (232)Th, (40)K and (137)Cs were measured in the uppermost part of the surface sediments of the two lakes, using gamma-ray spectrophotometry. Brullus Lake recorded significantly higher (238)U and (232)Th and lower (40)K (17.22±2.49, 10.03±0.56 and 299.70±17.78 Bq kg(-1)) than Mariout Lake (12.65±1.53, 7.24±0.76 and 518.75±46.24 Bq kg(-1), respectively). Cesium-137 shows nearly equal activities in both lakes (3.33±0.46 and 3.68±0.70 Bq kg(-1), respectively). Activity distributions of (238)U and (232)Th in the sediments of Mariout Lake show a significant increase to the west, southwest and northeast, (40)K activity increased westwards, while the (137)Cs level was increased to the east and northeast, indicating agriculture drainage, industrial wastes and lands reclamation around the lake. At Brullus Lake, the activity trends of (238)U, (232)Th, (40)K and(137)Cs were increasing to the west and south towards the agriculture and industrial waste-water-feeding drains. PMID:23630385

  19. Radiometric fingerprinting of fluvial sediments in the Rhine-Meuse delta, the Netherlands – a feasibility test

    NARCIS (Netherlands)

    Hebinck, K.; Middelkoop, H.; van Diepen, N.M; van der Graaf, E.R.; de Meijer, R.J.

    2007-01-01

    The deposits of the Rhine and the Meuse in the Netherlands alternate in their delta in a complex way. This paper discusses a method to distinguish the deposits of the Rhine and the Meuse based on the differences in natural radioactivity of (40)K, (238)U and (232)Th, and the effect of the age of the

  20. Radiometric fingerprinting of fluvial sediments in the Rhine-Meuse delta, the Netherlands – a feasibility test

    NARCIS (Netherlands)

    Hebinck, K.; Middelkoop, H.; Diepen, N. van; Graaf, E.R. van der; Meijer, R.J. de

    2007-01-01

    The deposits of the Rhine and the Meuse in the Netherlands alternate in their delta in a complex way. This paper discusses a method todistinguish the deposits of the Rhine and the Meuse based on the differences in natural radioactivity of 40K, 238U and 232Th, and the effect ofthe age of the deposits

  1. Determination of traces of uranium and thorium in titanium and copper used for the construction of the Russian Emission Detector 100 by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Poteshin, Sergey S; Sysoev, Alexey A; Lagunov, Sergey S; Sereda, Andrei; Sosnovtsev, Valery V; Bolozdynya, Alexander I; Efremenko, Yuriy B

    2015-01-01

    The Russian Emission Detector 100 (RED-100) under construction at the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) is designed to detect the presently undiscovered effect of coherent neutrino scattering. One of the factors limiting the sensitivity of the detector is the spontaneous decay of uranium and thorium in the detector materials. Radioactive impurities in detector materials at levels of parts per billion can significantly affect the sensitivity. Five random samples of titanium and one of copper from materials used in the construction of the detector were selected for assay. The concentration of (232)Th and (238)U were measured by inductively coupled plasma mass spectrometry (ICP- MS) in solid titanium using both: solutions in acids and direct sampling by laser ablation (LA-ICP-MS). The LA- ICP-MS method allowed us to determine (238)U and (232)Th at subnanogram per gram levels. This method is much faster than ICP-MS with liquid injection. The titanium samples studied have impurities in the range between 1 ng g(-1) and 21 ng g(-1) for (238)U and 3 ng g(-1) and 31 ng g(-1) for (232)Th. In copper we set upper limits of 0.4 ng g(-1) for (238)U and 1 ng g(-1)for (232)Th. The total activity of the cryostat constructed from materials studied was estimated to be 43 Bq. PMID:26307714

  2. GIS predictive mapping of terrestrial gamma radiation in the Northern State, Sudan

    International Nuclear Information System (INIS)

    This study presents the evaluation of absorbed dose in air due to gamma-emitting nuclides from 238U and 232Th series, 40K and 137Cs and the corresponding geographical information system (GIS) predictive mapping for the Northern State. Activity concentration of 238U, 232Th , 40K and 137Cs in soil samples collected from different locations have been measured using high resolution gamma spectrometry. On average, activity concentrations were 19±4 (238U), 47±11 (232Th), 317±65 (40K) and 2.26 Bq kg-1 for 137Cs. Absorbed dose rate in air at a height of 1 m above ground surface was calculated using seven sets of dose rate conversion factors (DRCFs) and the corresponding annual effective dose was estimated. On average, the values obtained fall within a narrow range of 44 and 53 nGy h-1, indicating that the variation in absorbed dose rate is insignificant for different DRCFs. The corresponding annual effective dose ranged from 53 to 65 μSv y-1. Using GIS, prediction maps for concentrations of 238U, 232Th, 40K and 137Cs were produced. Also, a map for absorbed dose rate in air at a height of 1 m above the ground level was produced, which showed a trend of increasing from the west towards south-east of the State. (authors)

  3. 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.

    Science.gov (United States)

    Misdaq, M A; Outeqablit, K

    2010-12-01

    (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 (Hammans) 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) μ Sv y(-1) cm(-2).

  4. 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

    2015-12-01

    Medicinal plant consumption can be a source of human exposure to radioactive elements such as (238)U and (232)Th, which can lead to internal radiation doses. The uptake of (238)U and (232)Th 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 (238)U, 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 (232)Th, 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., (238)U to (232)Th in the soil-plant leaves was 38.05 for E. globulus, 0.01 for A. mearnsii and 4.38 for H. filipendula. PMID:26690462

  5. A novel assay method for the trace determination of Th and U in copper and lead using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    This study describes a novel sample preparation and assay method developed, primarily in support of the MAJORANA DEMONSTRATOR neutrinoless double-beta decay experiment, for the determination of extremely low levels of Th and U in copper and lead shielding components. Meticulously clean sample preparation methods combined with anion exchange separations for analyte pre-concentration and matrix removal were developed. Quantification was performed by isotope dilution inductively coupled plasma mass spectrometry. Detection limits of 0.0084 pg 232Th/g (0.034 µBq 232Th/kg) and 0.0106 pg 238U/g (0.131 µBq 238U/kg) were determined for copper, while detection limits of 0.23 pg 232Th/g (0.94 µBq 232Th/kg) and 0.46 pg 238U/g (5.7 µBq 238U/kg) were achieved for lead. These methods allow the Majorana Collaboration to accurately assay detector components and ensure that the experiment's stringent radiopurity requirements are met

  6. Determination of traces of uranium and thorium in titanium and copper used for the construction of the Russian Emission Detector 100 by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Poteshin, Sergey S; Sysoev, Alexey A; Lagunov, Sergey S; Sereda, Andrei; Sosnovtsev, Valery V; Bolozdynya, Alexander I; Efremenko, Yuriy B

    2015-01-01

    The Russian Emission Detector 100 (RED-100) under construction at the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) is designed to detect the presently undiscovered effect of coherent neutrino scattering. One of the factors limiting the sensitivity of the detector is the spontaneous decay of uranium and thorium in the detector materials. Radioactive impurities in detector materials at levels of parts per billion can significantly affect the sensitivity. Five random samples of titanium and one of copper from materials used in the construction of the detector were selected for assay. The concentration of (232)Th and (238)U were measured by inductively coupled plasma mass spectrometry (ICP- MS) in solid titanium using both: solutions in acids and direct sampling by laser ablation (LA-ICP-MS). The LA- ICP-MS method allowed us to determine (238)U and (232)Th at subnanogram per gram levels. This method is much faster than ICP-MS with liquid injection. The titanium samples studied have impurities in the range between 1 ng g(-1) and 21 ng g(-1) for (238)U and 3 ng g(-1) and 31 ng g(-1) for (232)Th. In copper we set upper limits of 0.4 ng g(-1) for (238)U and 1 ng g(-1)for (232)Th. The total activity of the cryostat constructed from materials studied was estimated to be 43 Bq.

  7. Radionuclide contents in suspended sediments in relation to flood types in the lower Rhone River

    International Nuclear Information System (INIS)

    The aim of this work was to study the influence of watershed heterogeneity on the radionuclide contents of suspended particulate matter (SPM) in a large Mediterranean river. As the Rhone River catchment is characterized by a high climatic and geological heterogeneity, floods can be distinguished according to their geographic origins. Long-term time series of particles associated with radionuclides acquired in the framework of radiological surveillance provide a relevant dataset to investigate the variability of radionuclide contents. The SPM exported during Mediterranean floods differ from other floods as they display higher 238U and 232Th contents and the lowest activity ratio 137Cs/(239+240)Pu; these properties could be related to bedrock type and erosion process characteristics and/or to source term differentiation. (authors)

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

    Directory of Open Access Journals (Sweden)

    SCEPAN S. MILJANIC

    2007-06-01

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

  9. Gamma-Ray Measurements of Naturally Occurring Radioactive Materials in Sludge, Scale and Well Cores of the Oil Industry in Southern Iraq

    Directory of Open Access Journals (Sweden)

    Abdul Ridha Hussain SUBBER

    2013-12-01

    Full Text Available Radioactivity of nuclides 238U, 226Ra, 232Th and 40K was measured in soil by γ-ray spectrometry using a NaI (Li detector. A criterion was set in order to analyze sludge samples from oil fields and oil well-cores in southern Basrah, in the Iraq oil fields. More than 3 γ-ray energy peaks were used for the determination of 226Ra and 232Th activity concentrations to obtain results that are more accurate. Relationships between the measured radionuclides were discussed. Radionuclides 238U and 226Ra were found in disequilibrium with ratio of specific activities (238 U/226 Ra less than unity for most of the sludge and core samples. The content of radioactive elements in the sludge, scale and well core is found within the range of other petroleum countries in the region.doi:10.14456/WJST.2014.93

  10. Nuclear energy release from fragmentation

    CERN Document Server

    Li, Cheng; Tsang, M B; Zhang, Feng-Shou

    2015-01-01

    Nuclear energy released by splitting Uranium and Thorium isotopes into two, three, four, up to eight fragments with nearly equal size are studied. We found that the energy released come from equally splitting the $^{235,238}$U and $^{230,232}$Th nuclei into to three fragments is largest. The statistical multifragmentation model is employed to calculate the probability of different breakup channels for the excited nuclei. Weighing the the probability distributions of fragments multiplicity at different excitation energies for the $^{238}$U nucleus, we found that an excitation energy between 1.2 and 2 MeV/u is optimal for the $^{235}$U, $^{238}$U, $^{230}$Th and $^{232}$Th nuclei to release nuclear energy of about 0.7-0.75 MeV/u.

  11. Effects of source rocks, soil features and climate on natural gamma radioactivity in the Crati valley (Calabria, Southern Italy).

    Science.gov (United States)

    Guagliardi, Ilaria; Rovella, Natalia; Apollaro, Carmine; Bloise, Andrea; De Rosa, Rosanna; Scarciglia, Fabio; Buttafuoco, Gabriele

    2016-05-01

    The study, which represents an innovative scientific strategy to approach the study of natural radioactivity in terms of spatial and temporal variability, was aimed to characterize the background levels of natural radionuclides in soil and rock in the urban and peri-urban soil of a southern Italy area; to quantify their variations due to radionuclide bearing minerals and soil properties, taking into account nature and extent of seasonality influence. Its main novelty is taking into account the effect of climate in controlling natural gamma radioactivity as well as analysing soil radioactivity in terms of soil properties and pedogenetic processes. In different bedrocks and soils, activities of natural radionuclides ((238)U, (232)Th (4) K) and total radioactivity were measured at 181 locations by means of scintillation γ-ray spectrometry. In addition, selected rocks samples were collected and analysed, using a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS) and an X-Ray Powder Diffraction (XRPD), to assess the main sources of radionuclides. The natural-gamma background is intimately related to differing petrologic features of crystalline source rocks and to peculiar pedogenetic features and processes. The radioactivity survey was conducted during two different seasons with marked changes in the main climatic characteristics, namely dry summer and moist winter, to evaluate possible effects of seasonal climatic variations and soil properties on radioactivity measurements. Seasonal variations of radionuclides activities show their peak values in summer. The activities of (238)U, (232)Th and (4) K exhibit a positive correlation with the air temperature and are negatively correlated with precipitations. PMID:26891362

  12. Radon concentration in soil gas and its correlations with pedologies, permeabilities and 226Ra content in the soil of the Metropolitan Region of Belo Horizonte - RMBH, Brazil

    Science.gov (United States)

    Lara, E.; Rocha, Z.; Palmieri, H. E. L.; Santos, T. O.; Rios, F. J.; Oliveira, A. H.

    2015-11-01

    The radon concentration in soil gas is directly dependent on the geological characteristics of the area, such as lithology, pedology and on geochemicals, physicals and mineralogicals parameters of the soil. This paper looks for correlations between radon concentrations in soil gas and its soil permeability, 238U, 232Th and 226Ra contents in the soil groups classified by pedologies of Metropolitan Region of Belo Horizonte (RMBH), Minas Gerais, Brazil. The soil gas radon concentrations were determined by using an AlphaGUARD® monitor at about 150 measurement points. In soil samples of the same measurement points, the concentrations of 226Ra were determined by gamma spectrometry (HPGe), and 238U and 232Th by ICP-MS. The soil permeabilities were determined by using the RADON-JOK® permeameter. The mean concentrations of radon in soil gas ranged from 13.6±3.0 kBq m-3 for Litholic Neosols until 60.6±8.7 kBq m-3 for Perferric Red Latosols. The mean of 226Ra activity concentrations presented variation of 12.4±2.5 Bq kg-1 for Litholic Neosols until 50.3±13 Bq kg-1 for Perferric Red Latosols. Approximately 40% of the soils presented high permeability. The areas of different pedologies were classified by Soil Radon Index (SRI), determined by the soil gas radon concentration and permeability. Approximately 53% of the Perferric Red Latosols measurement site could be classified as "High Risk" (Swedish criteria). The preliminary results may indicate an influence of iron formations present very close to the Perferric Red Latosols in the retention of uranium minerals, and hence an increase in the concentration of radon and radium, whereas the series are in equilibrium in the environment.

  13. The enrichment behavior of natural radionuclides in pulverized oil shale-fired power plants.

    Science.gov (United States)

    Vaasma, Taavi; Kiisk, Madis; Meriste, Tõnis; Tkaczyk, Alan Henry

    2014-12-01

    The oil shale industry is the largest producer of NORM (Naturally Occurring Radioactive Material) waste in Estonia. Approximately 11-12 million tons of oil shale containing various amounts of natural radionuclides is burned annually in the Narva oil shale-fired power plants, which accounts for approximately 90% of Estonian electricity production. The radionuclide behavior characteristics change during the fuel combustion process, which redistributes the radionuclides between different ash fractions. Out of 24 operational boilers in the power plants, four use circulating fluidized bed (CFB) technology and twenty use pulverized fuel (PF) technology. Over the past decade, the PF boilers have been renovated, with the main objective to increase the efficiency of the filter systems. Between 2009 and 2012, electrostatic precipitators (ESP) in four PF energy blocks were replaced with novel integrated desulphurization technology (NID) for the efficient removal of fly ash and SO2 from flue gases. Using gamma spectrometry, activity concentrations and enrichment factors for the (238)U ((238)U, (226)Ra, (210)Pb) and (232)Th ((232)Th, (228)Ra) family radionuclides as well as (40)K were measured and analyzed in different PF boiler ash fractions. The radionuclide activity concentrations in the ash samples increased from the furnace toward the back end of the flue gas duct. The highest values in different PF boiler ash fractions were in the last field of the ESP and in the NID ash, where radionuclide enrichment factors were up to 4.2 and 3.3, respectively. The acquired and analyzed data on radionuclide activity concentrations in different PF boiler ashes (operating with an ESP and a NID system) compared to CFB boiler ashes provides an indication that changes in the fuel (oil shale) composition and boiler working parameters, as well as technological enhancements in Estonian oil shale fired power plants, have had a combined effect on the distribution patterns of natural radionuclides

  14. Effects of source rocks, soil features and climate on natural gamma radioactivity in the Crati valley (Calabria, Southern Italy).

    Science.gov (United States)

    Guagliardi, Ilaria; Rovella, Natalia; Apollaro, Carmine; Bloise, Andrea; De Rosa, Rosanna; Scarciglia, Fabio; Buttafuoco, Gabriele

    2016-05-01

    The study, which represents an innovative scientific strategy to approach the study of natural radioactivity in terms of spatial and temporal variability, was aimed to characterize the background levels of natural radionuclides in soil and rock in the urban and peri-urban soil of a southern Italy area; to quantify their variations due to radionuclide bearing minerals and soil properties, taking into account nature and extent of seasonality influence. Its main novelty is taking into account the effect of climate in controlling natural gamma radioactivity as well as analysing soil radioactivity in terms of soil properties and pedogenetic processes. In different bedrocks and soils, activities of natural radionuclides ((238)U, (232)Th (4) K) and total radioactivity were measured at 181 locations by means of scintillation γ-ray spectrometry. In addition, selected rocks samples were collected and analysed, using a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive Spectrometer (EDS) and an X-Ray Powder Diffraction (XRPD), to assess the main sources of radionuclides. The natural-gamma background is intimately related to differing petrologic features of crystalline source rocks and to peculiar pedogenetic features and processes. The radioactivity survey was conducted during two different seasons with marked changes in the main climatic characteristics, namely dry summer and moist winter, to evaluate possible effects of seasonal climatic variations and soil properties on radioactivity measurements. Seasonal variations of radionuclides activities show their peak values in summer. The activities of (238)U, (232)Th and (4) K exhibit a positive correlation with the air temperature and are negatively correlated with precipitations.

  15. Element enrichment and U-series isotopic characteristics of the hydrothermal sulfides at Jade site in the Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    ZENG ZhiGangi; YU ShaoXiong; YIN XueBo; WANG XiaoYuan; ZHANG GuoLiang; WANG XiaoMei; CHEN DaiGeng

    2009-01-01

    The geochemical and U-series isotopic characteristics of hydrothermal sulfide samples from the Jade site (127°04.5'E, 27°15'N, water depth 1300-1450 m) at Jade site in the Okinawa Trough were analyzed. In the hydrothermal sulfide samples bearing sulfate (samples HOK1 and HOK2), the LREEs are rela- tively enriched. All the hydrothermal sulfide samples except HOK1 belong to Zn-rich hydrothermal sul- fide. In comparison with Zn-rich hydrothermal sulfides from other fields, the contents of Zn, Pb, Ag, Cd, Au and Hg are higher, the contents of Fe, Al, Cr, Co, Ni, Sr, Te, Ca, Ti and U lower, and the 210Pb radio- activity ratios and 210Pb/Pb ratios very low. In the hydrothermal sulfide mainly composed of sphalerite, the correlations between rare elements Hf and U, and Hf and Mn as well as that between dispersive elements Ga and Zn, are strongly positive; also the contents of Au and Ag are related to Fe-aulfide, because the low temperature promotes enrichment of Au and Ag. Meanwhile, the positive correlations between Fe and Bi and between Zn and Cd are not affected by the change of mineral assemblage. Based on the 210Pb/Pb ratios of hydrothermal sulfide samples (3.99x10-5-.42x10-5), their U isotopic composition (238 U content 1.15-2.53 ppm, 238U activity 1.07-1.87 dpm/g, 234U activity 1.15-2.09 dpm/g and 234U/238U ratio 1.07-1.14) and their 222Th and 230Th contents are at base level, and the chronological age of hydrothermal sulfide at Jade site in the Okinawa Trough is between 200 and 2000 yr.

  16. Excitation-energy dependence of the nuclear fission characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Baba, H.; Saito, T.; Takahashi, N. [Osaka City Univ. (Japan). Faculty of Science] [and others

    1996-03-01

    It is known that the width parameter of the fragment mass yield distribution follows a beautiful systematics with respect to the excitation energy. According to this systematics, the fission characteristics following the systematics should disappear when the excitation energy Ex goes down to 14 MeV. The present purpose is to elucidate if, where, how and why a transition takes place in the fission characteristics of the asymmetric fission of light actinide elements. Two types of experiments are performed, one is the double-energy measurement of the kinetic energies of complementary fragments in the thermal-neutron fission of {sup 235,233}U and proton-induced fission of {sup 238}U at 13.3- and 15.7-MeV excitations, and the other is the radiochemical study of proton-induced fission and photofission of {sup 238}U at various excitation energies. In conclusion, it has demonstrated that there are two distinctive fission mechanisms in the low-energy fission of light actinide elements and the transition between them takes place around 14-MeV excitation. The characteristics of proton fission and photofission in the energy range lower than the above transition point are the essentially the same as those of thermal-neutron fission and also spontaneous fission. The results of GDR fission indicates the fission in the high-energy side starts from the nuclear collective states, whereas the lower-energy fission is of non-collective nature. It is likely that thermal-neutron fission is rather of the barrier-penetrating type like spontaneous fission than the threshold fission. (S.Y.)

  17. Burnup analysis of the VVER-1000 reactor using thorium-based fuel

    Energy Technology Data Exchange (ETDEWEB)

    Korkmaz, Mehmet E.; Agar, Osman; Bueyueker, Eylem [Karamanoglu Mehmetbey Univ., Karaman (Turkey). Faculty of Kamil Ozdag Science

    2014-12-15

    This paper aims to investigate {sup 232}Th/{sup 233}U fuel cycles in a VVER-1000 reactor through calculation by computer. The 3D core geometry of VVER-1000 system was designed using the Serpent Monte Carlo 1.1.19 Code. The Serpent Code using parallel programming interface (Message Passing Interface-MPI), was run on a workstation with 12-core and 48 GB RAM. {sup 232}Th/{sup 235}U/{sup 238}U oxide mixture was considered as fuel in the core, when the mass fraction of {sup 232}Th was increased as 0.05-0.1-0.2-0.3-0.4 respectively, the mass fraction of {sup 238}U equally was decreased. In the system, the calculations were made for 3 000 MW thermal power. For the burnup analyses, the core is assumed to deplete from initial fresh core up to a burnup of 16 MWd/kgU without refuelling considerations. In the burnup calculations, a burnup interval of 360 effective full power days (EFPDs) was defined. According to burnup, the mass changes of the {sup 232}Th, {sup 233}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 241}Am and {sup 244}Cm were evaluated, and also flux and criticality of the system were calculated in dependence of the burnup rate.

  18. Burnup analysis of the VVER-1000 reactor using thorium-based fuel

    International Nuclear Information System (INIS)

    This paper aims to investigate 232Th/233U fuel cycles in a VVER-1000 reactor through calculation by computer. The 3D core geometry of VVER-1000 system was designed using the Serpent Monte Carlo 1.1.19 Code. The Serpent Code using parallel programming interface (Message Passing Interface-MPI), was run on a workstation with 12-core and 48 GB RAM. 232Th/235U/238U oxide mixture was considered as fuel in the core, when the mass fraction of 232Th was increased as 0.05-0.1-0.2-0.3-0.4 respectively, the mass fraction of 238U equally was decreased. In the system, the calculations were made for 3 000 MW thermal power. For the burnup analyses, the core is assumed to deplete from initial fresh core up to a burnup of 16 MWd/kgU without refuelling considerations. In the burnup calculations, a burnup interval of 360 effective full power days (EFPDs) was defined. According to burnup, the mass changes of the 232Th, 233U, 238U, 237Np, 239Pu, 241Am and 244Cm were evaluated, and also flux and criticality of the system were calculated in dependence of the burnup rate.

  19. Hydride interference on the determination of minor actinide isotopes by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Hydrogen adducts of the major naturally occurring actinide isotopes 232Th and 238U were studied using an inductively coupled plasma mass spectrometer. The hydride:atomic ion ratios for both elements varied as a function of the parameters that were studied, i.e., nebulizer flow rate, solution uptake rate and desolvation conditions. When the instrument sensitivity for U and Th was optimized, 232ThH+:232Th+ was found to be (3.9±0.2) x 10-5 with pneumatic nebulization and (2.10±0.07) x 10-5 with ultrasonic nebulization. Under the same conditions, 238UH+:238U+ was found to be (3.2±0.2) x 10-5 and (1.8±0.1) x 10-5 using pneumatic and ultrasonic nebulization, respectively. Conditions that reduced hydrogen number density and/or increased plasma temperature decreased the hydride:atomic ion ratio. Such conditions are best if 233U and 239Pu are to be determined in the presence of 232Th and 238U. (Author)

  20. Natural radioactivity of coal and fly ash at the Nikola Tesla B TPP

    Directory of Open Access Journals (Sweden)

    Kisić Dragica M.

    2013-01-01

    Full Text Available Serbian thermal power plants (TPPs produce siliceous fly ash from lignite in the quantity of approximately 6 million tons per year. The potential market for the use of fly ash is operational, but for the time being, only used by cement producers. Fly ash radioactivity could be one of the major points of concern when larger use of fly ash is planned, particularly in the Serbian construction industry. Radioactivity measurements have been conducted regularly for decades. This paper presents the results of a ten-year fly ash radioactivity measurements at the Nikola Tesla B TPP located in Obrenovac. In addition, the paper compares the natural radionuclides coal content data combusted by the Nikola Tesla B TPP boilers coming from the Kolubara Basin and ash created during coal combustion. Fly ash created in the Nikola Tesla TPPs boilers is characterised by the increased concentration of the natural radionuclides content compared to coal. This is the so-called technologically enhanced natural radioactivity (Technologically Enhanced Occurring Radioactive Material - TENORM of industrial waste, whereas the average specific activities: 232Th in coal amount to 25.2 Bq/kg, and in fly ash and coal 84.2 Bq/kg and 238U 38.3 Bq/kg, respectively. Following the obtained natural radionuclides content results it may be concluded that the Nikola Tesla B TPP ash may be disposed into the environment. Ash may be used also in the construction industry (civil engineering. In building construction applications, ash share as the additive to other building materials depends from its physical and chemical characteristics, as well as from the radionuclides activity: 266Ra, 232Th and 40K. Unlike the thermal power plants regularly (once a year testing the specific natural radionuclides activity in the combusted coal and boiler fly ash, Electric Power Industry of Serbia has not performed large-scale investigations of the natural radionuclides content in coal within the Kolubara

  1. High energy X-ray spectrometer on the Chandrayaan-1 mission to the Moon

    Indian Academy of Sciences (India)

    J N Goswami; D Banerjee; N Bhandari; M Shanmugam; Y B Acharya; D V Subhedar; M R Sharma; C N Umapathy; P Sreekumar; M Sudhakar; L Abraham; P C Agrawal

    2005-12-01

    The Chandrayaan-1 mission to the Moon scheduled for launch in late 2007 will include a high energy X-ray spectrometer (HEX) for detection of naturally occurring emissions from the lunar surface due to radioactive decay of the 238U and 232Th series nuclides in the energy region 20 –250 keV.The primary science objective is to study the transport of volatiles on the lunar surface by detection of the 46.5 keV line from radioactive 210Pb, a decay product of the gaseous 222Rn, both of which are members of the 238U decay series. Mapping of U and Th concentration over the lunar surface, particularly in the polar and U –Th rich regions will also be attempted through detection of prominent lines from the U and Th decay series in the above energy range.The low signal strengths of these emissions require a detector with high sensitivity and good energy resolution.Pixelated Cadmium – Zinc –Telluride (CZT)array detectors having these characteristics will be used in this experiment. Here we describe the science considerations that led to this experiment,anticipated flux and back- ground (lunar continuum),the choice of detectors,the proposed payload con figuration and plans for its realization.

  2. Assessment of radionuclide and metal contamination in a thorium rich area in Norway.

    Science.gov (United States)

    Popic, Jelena Mrdakovic; Salbu, Brit; Strand, Terje; Skipperud, Lindis

    2011-06-01

    The Fen Central Complex in southern Norway, a geologically well investigated area of magmatic carbonatite rocks, is assumed to be among the world largest natural reservoirs of thorium ((232)Th). These rocks, also rich in iron (Fe), niobium (Nb), uranium ((238)U) and rare earth elements (REE), were mined in several past centuries. Waste locations, giving rise to enhanced levels of both radionuclides and metals, are now situated in the area. Estimation of radionuclide and metal contamination of the environment and radiological risk assessment were done in this study. The average outdoor gamma dose rate measured in Fen, 2.71 μGy h(-1), was significantly higher than the world average dose rate of 0.059 μGy h(-1). The annual exposure dose from terrestrial gamma radiation, related to outdoor occupancy, was in the range 0.18-9.82 mSv. The total activity concentrations of (232)Th and (238)U in soil ranged from 69 to 6581 and from 49 to 130 Bq kg(-1), respectively. Enhanced concentrations were also identified for metals, arsenic (As), lead (Pb), chromium (Cr) and zinc (Zn), in the vicinity of former mining sites. Both radionuclide and heavy metal concentrations suggested leaching, mobilization and distribution from rocks into the soil. Correlation analysis indicated different origins for (232)Th and (238)U, but same or similar for (232)Th and metals As, Cr, Zn, nickel (Ni) and cadmium (Cd). The results from in situ size fractionation of water demonstrated radionuclides predominately present as colloids and low molecular mass (LMM) species, being potentially mobile and available for uptake in aquatic organisms of Norsjø Lake. Transfer factors, calculated for different plant species, showed the highest radionuclide accumulation in mosses and lichens. Uptake in trees was, as expected, lower. Relationship analysis of (232)Th and (238)U concentrations in moss and soil samples showed a significant positive linear correlation. PMID:21556423

  3. 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)

  4. Radioactivity in raw materials and end products in the Italian ceramics industry

    International Nuclear Information System (INIS)

    The natural radioactivity due to the presence of 238U, 232Th and 40K in zirconium minerals (zircon and baddeleyite) used in the Italian ceramics industry, in tiles and in waste sludges resulting from ceramic processes, has been measured. The measurements were made by γ-ray spectrometry with a high-purity germanium (HPGe) detector connected to a multichannel analyser. The average concentrations of 238U and 232Th observed in the mineral samples (>3000 and >500 Bq kg-1, respectively) are higher than the concentrations found in the earth's crust by one or two orders of magnitude. The specific activities of tiles and sludges are much lower than in zirconium minerals. The 238U and 232Th concentrations in tiles (50-79 and 52-66 Bq kg-1, respectively) are not higher than in other building materials. The 238U concentration of sludges (116-193 Bq kg-1) is 4-6 times higher than the mean value for the earth's crust. The results are examined on the basis of the existing Italian legislation (D.Lgs no. 230, 1995, Gazzetta Ufficiale 13/06/1996, no. 136, Supplemento Ordinario, Rome, Italy) and the EC Directive no. 29/Euratom of the year 1996 (Gazzetta Ufficiale della Communita Europea 29/06/1996, no. L159)

  5. Radionuclide activities and radiological impact from the intake of milk, wheat flour, tea and coffee

    International Nuclear Information System (INIS)

    Full-text: The annual intake of four naturally occurring radionuclides 226Ra, 238U, 232Th and 40K from powdered milk, wheat flour, tea and coffee for Malaysian population were estimated using gamma spectrometry system. The radionuclides annual intake of 226Ra ranged from 6 to 35.7 Bq, 232Th ranged from 7.6 to 57.7 Bq, 238U ranged from 6.3 to 63.7 Bq and 40K ranged from 771.8 to 1707.5 Bq for adults. The means of these intakes were 28.8 Bq for 226Ra, 38.5 Bq for 232Th, 28.1 Bq for 238U and 2921.1 Bq for the 40K. The annual intake of radionuclide for infants were found to be 66.2 Bq for 226Ra, 71.6 Bq for 232Th, 23 Bq for 238U and 7774.8 Bq for 40K. the annual internal dose for infants from the intake of powdered milk were 63.5 μSv for 226Ra, 32.2 μSv for 232Th, 2.8 μSv for 238U and 326.5 μSv for 40K. The measured values also gives annual internal dose of 13.7 μSv 226Ra, 19 μSv for 232Th, 4 μSv for 238U and 24.2 μSv for 40K for adult population. The net radiological impact of these radionuclides is 425 μSv for infants and 60.9 μSv for adults. This value gives cancer risk factor of 1.8 x 10-3 for infants and 1.7 x 10-4 for adults. The probability of cancer risk increment is estimated as 0.18 % for infants (18 person in 10000) and 0.017 % for adults (1.7 person in 10000). Whereas ICRP cancer risk factor for general public is 2.5 x 10-3 nd the total risk involved from all natural radiation sources based on global average radiation dose of 2.4 mSv is of 6 x 10-3. The estimated cancer risk shows that probability of increase of cancer risk from intake of milk, wheat flour, tea and coffee is only a minor fraction of ICRP values. Therefore, the diet does not pose any significant health hazard and is considered safe for human consumption. (author)

  6. Gamma radioactivity in sediments of Maracaibo Lake, Venezuela

    International Nuclear Information System (INIS)

    Maracaibo Lake is located to the west part of Venezuela (see Figure), with a surface of 13.000 Km2, its coast embraces a longitude of 729 Km. This lake is the largest fresh water hydrologic basin of Venezuela and its ecosystem is subjected to intense and constant modification due to the strong oil exploitation developed in this region. Both in the coastal area and inside the lake, the petroleum extraction process induces modification in the ecosystem. Radioactive content characterization was carried out in coastal sediments of Maracaibo Lake, measuring the specific activity of the following elements: 40K, gamma emitters of the natural radioactive series (238U and 232Th) and radioactive elements of anthropogenic origin (137Cs, among others) and cosmogenic as Berilium-7. The radioactive disequilibrium in the 238U and 232Th series was evaluated. Surface samples (from depth up to 5 cm) of the sediments along the coast were recollected and measured by high resolution gamma spectroscopy using a HpGe detector of approximately 2 KeV resolution for the 1,33 MeV 60Co peak and efficiency higher than 20% (supplied under the IAEA Technical Co-operation Project VEN/9/005). The 137Cs concentrations ranged in the interval 0,5-13,1 Bq/kg, while those of natural radionuclides are 238U (2,12 - 5,01 ppm), 232Th (6,71-38,58 ppm) and 40K (1,05-3,64%), assuming radioactive equilibrium in samples. Between elements of the 238U series high correlation was obtained while it is low between those of the 232Th series, being evidenced radioactive disequilibrium in this series. We found high positive correlation between 40K and elements of the 232Th series, and in turn low and negative with those of the 238U series. 232Th and 238U correlate negatively one to each other. This coastal sediment characterization of Maracaibo Lake allowed us to obtain a map of radioactive levels in these areas, which will serve as reference for future investigations. Reference sample for this study were supplied by

  7. Fast-neutron capture cross sections of importance in technological applications

    International Nuclear Information System (INIS)

    The importance of the capture cross section of the major fertile nuclei, 238U and 232Th, leads to the consideration of these data. The 238U (n,γ) cross section is considered of priority as it is part of the 238U-239Pu cycle. Experimental techniques used in the measurements of these data are considered. Data measured more recently are compared with provisions made for the possible explanations of differing results. It is concluded that the 238U (n,γ) cross section is known with approx. 5% above 10 keV and fulfills the uncertainty limit for this cross section set to achieve design accuracy for k/sub eff/ and the breeding ratio above 500 keV. Below 500 keV, the present uncertainty falls short of the required 1.5 to 3.0% uncertainty. Specific recommendations are made to resolve existing discrepancies and data uncertainties. 84 references

  8. Correlations of natural radionuclides in soil with those in sediment from the Danube and nearby irrigation channels.

    Science.gov (United States)

    Krmar, M; Varga, E; Slivka, J

    2013-03-01

    The correlation between activity concentrations of some natural radionuclides ((238)U, (226)Ra, (232)Th, (40)K) measured in soil and in sediment taken from the Danube River and nearby irrigation channels was studied. The soil samples were collected from the northern part of Serbia and the sediment from the Serbian part of the Danube River and from the surrounding irrigation channels. The correlation between (238)U and other natural radionuclides in irrigation channel sediments was not as good as in the Danube. One of the possible explanations for this weak correlation can be the different chemical dynamics of (238)U in the irrigation channel sediment or changes of the (238)U activity concentration in irrigation channel sediment due to some human activities. The evaluation of ratios of activity concentrations of some natural radionuclides could be a more sensitive method for the determination of contaminant, rather than the straightforward analysis of activity concentrations. PMID:22244685

  9. Development of Analytical methods for the evaluation of the impact of phosphate fertilizer industry on marine environment

    International Nuclear Information System (INIS)

    Phosphate industries are considered an important potential source of natural radionuclides and heavy metals contamination in the environment. The objective of this work was to assess the marine environmental metallic and radiological pollution and the toxicological impact caused by a large production plant of phosphate fertilizer located on the eastern coast of the Mediterranean Sea, 40 km north of the capital of Lebanon: Beirut. Since 1957 this industry has been producing a large set of phosphate based fertilizers. Phosphogypsum, by-product resulting in the industrial procedure, is released directly in the marine environment. Natural radionuclides (238U, 235U, 226Ra, 232Th, 210Po, 210Pb, and 40K) and anthropogenic 137Cs were measured by alpha and gamma spectrometry in seawater, sediment, coastal sediment and biota. An alpha spectrometer with a passive ion implanted silicon detector was used for the determination of 238U, 234Uin sea water and 210Poin biota samples. 238U, 235U, 232Th, 226Ra,210Pb,137Cs and 40Kin biota and sediments were analyzed by a gamma spectrometer from Canberra, equipped with an extended range low-level coaxial high purity germanium detector with beryllium window.In addition, the radiation exposure of the population surrounding the industrial plant and the internal exposure and potential risks to human due to 210Poand 210Pbassociated with the consumption of fish have been estimated. The internal exposure due to the consumption of fish is important from the radioecology and radioprotection perspectives, and the data for most species studied, are reported for the first time in Lebanon. A multi-elemental method for simultaneous determination of trace elements in seaweeds based on the use of the new approach of collision reaction interface for the ICP-MS determination was optimized. The performance characteristics including linearity, limits of detection and quantification, repeatability, accuracy and truenesswere evaluated. Investigations on the

  10. Study of radioactivity levels in detergent powders samples by gamma spectroscopy

    OpenAIRE

    Ali A. Abojassim; Hussain H. Abd; Dalal N. Hamed; Anmar A. Abdullah

    2014-01-01

    This study focuses on the evaluation of the natural radioactivity levels in ten samples of the detergent powders that available in Iraqi markets. We have determined the specific activities of uranium, thorium and potassium using gamma spectroscopy and calculation of radiation hazard indices. The results of the activities of radionuclides (238U, 232Th, 40K) for detergent powders samples, are found that the 238U specific activities were varied from (11.489 ± 2.089) Bq/kg to (36.062 ± 2.478) Bq/...

  11. Hope and Inquietudes in Nucleo-cosmochronology

    CERN Document Server

    Arnould, M

    2001-01-01

    Critical views are presented on some nucleo-cosmochronological questions. Progress has been made recently in the development of the 187Re-187Os cosmochronometry. From this, there is good hope for this clock to become of the highest quality for the nuclear dating of the Universe. The simultaneous observation of Th and U in ultra-metal-poor stars would also be a most interesting prospect. In contrast, a serious inquietude is expressed about the reliability of the chronometric attempts based on the classical 232Th-238U and 235U-238U pairs, as well as on the Th (without U) abundance determinations in ultra-metal poor stars.

  12. Hope and Inquietudes in Nucleocosmochronology

    Science.gov (United States)

    Arnould, M.; Goriely, S.

    Critical views are presented on some nucleo-cosmochronological questions. Progress has been made recently in the development of the 187Re-187Os cosmochronometry. From this, there is good hope for this clock to become of the highest quality for the nuclear dating of the Universe. The simultaneous observation of Th and U in ultra-metal-poor stars would also be a most interesting prospect. In contrast, a serious inquietude is expressed about the reliability of the chronometric attempts based on the classical 232Th-238U and 235U-238U pairs, as well as on the Th (without U) abundance determinations in ultra-metal poor stars.

  13. Radioactivity level of the ambient environment of Anren bone-coal power station

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The radioactivity level of the ambient environment of Anren Bonc-coalPower Station (BCPS) was investigated systematically. The γ radiation dose ratelevel in the environment, the content of 238U and 226Ra in the ambient soil and thefarmland in the direction of downwind, the concentrations of 238U, 232Th, 226Ra, 40Kand 222Rn, as well as α potential energy in air, and the concentrations of natural Uand Th in effluent are all higher than the corresponding values of the reference site.The additional annual effective dose equivalent to the residents living in the housesmade of bone-coal cinder brick is 2.7mSv.

  14. Monitoring of natural radioactivity in manganese ore

    International Nuclear Information System (INIS)

    The natural radionuclides (238U, 232Th, and 40K) contents of Manganese ore collected by Sinai Manganese Company in Egypt-Cairo have been determined by low background spectroscopy using hyper-pure germanium (HPGe) detector. The mean activities due to the three radionuclides (238U, 232Th, and 40K) were found to be 3543 ± 106, 222 ± 6.6 and 3483 ± 104 Bq/kg, respectively. The absorbed dose rates due to the natural radioactivity in samples under investigation ranged from 1522 ± 45 to 1796 ± 53 nGy/h. The radium equivalent activity varied from 3807 ± 114 to 4446 ± 133 Bq/kg. Also, the representative external hazard index values for the corresponding samples were estimated.

  15. A novel assay method for the trace determination of Th and U in copper and lead using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    This study describes a novel sample preparation and assay method developed in support of the MAJORANA DEMONSTRATOR experiment for the determination of thorium and uranium levels in copper and lead shielding components. Meticulously clean sample preparation methods combined with novel anion exchange separations for analyte pre-concentration and matrix removal were developed. Quantification was performed by inductively coupled plasma mass spectrometry. Detection limits of 0.0084 pg 232Th/g and 0.0106 pg 238U/g were determined for copper, while detection limits of 0.23 pg 232Th/g and 0.46 pg 238U/g were achieved for lead. These methods allow the Majorana Collaboration to accurately assay detector components and ensure that the experiment's stringent radiopurity requirements are met.

  16. Evaluation of radioactive emissions of lignite-fired power plants in Turkey using the Analytic Hierarchy Process

    Energy Technology Data Exchange (ETDEWEB)

    Bueke, Tayfun [Mugla Sitki Kocman Univ., Mugla (Turkey). Dept. of Energy Systems Engineering

    2013-11-15

    Radioactive emissions of 13 lignite-fired power plants in Turkey are of great concern to the public and to scientists alike. The purpose of this study is to evaluate these power plants, according to their radioactive emissions by using the Analytic Hierarchy Process. Control criteria are in particular {sup 226}Ra, {sup 232}Th, {sup 40}K and {sup 238}U emissions from the power plants. These control criteria are weighted according to the objective assessment. The calculations are repeated for three different objective assessments of control criteria namely the mortality risk coefficients for inhalation, ingestion, external exposure of {sup 226}Ra, {sup 232}Th, {sup 40}K and {sup 238}U. It has been calculated that the Can lignite-fired power plant is ranking first while the Soma-B plant is ranking last according to the radioactive emissions of the power plants when the average of three different objective control criteria are used in the calculations. (orig.)

  17. Hydrogeochemical utilization of natural isotopes from U(4n+2) and Th(4n) series at Morro do Ferro, Pocos de Caldas (MG)

    International Nuclear Information System (INIS)

    Uranium and thorium isotopic analysis were performed on well spoils of the main ore body at Morro do Ferro, Pocos de Caldas (MG), using groundwater from several boreholes in the area and surface water from a steam that originates at the base of the hill. For extraction of uranium and thorium a long chemical process was applied to samples; activities of 228Th and 232 Th isotopes (4n series) and also of 238U, 234U and 230Th isotopes (4n+2 series)were determined by the alpha spectrometry method. The ratios 234U?238U determined for well spoils did not show marked disequilibria between these isotopes. However, the ratios 228Th/232Th and 230Th/234U obtained in some samples showed a high disequilibrium between these isotopes, associated with the presence of possible zones of removal of uranium and precipitation of radium.(author)

  18. Radioactivity of beach sand in the south western coast of Sri Lanka

    International Nuclear Information System (INIS)

    The activity concentrations and effective dose rates due to 232Th, 238U and 40K were determined for sand samples collected along the coastal strip from Crow Island to Beruwala, a part of south western coast of Sri Lanka, using a high-purity germanium detector. The ranges and the mean activity concentrations measured were (11-19 600, 2100), (7-3150, 450) and (14-1210, 220) Bq kg-1 for 232Th, 238U and 40K, respectively. The effective annual gamma dose in the area ranged from 0.004 to 16.8 mSv y-1. For 21 % of the locations, the annual effective dose determined from the activity concentrations exceeded the average worldwide exposure of 2.4 mSv y-1. (authors)

  19. Radiological Impact of Phosphogypsum Application in Agriculture

    International Nuclear Information System (INIS)

    Phosphogypsum (PG) contains radionuclides from 238U and 232Th decay series. Due to the presence of these radionuclides, many countries restricted the use of PG in agriculture, however there is not such restriction in Brazil. The main objective of this work was to evaluate the impact of PG application on 226Ra (238U) and 228Ra (232Th) concentrations in soil. Gamma-spectrometry was carried out using HPGe detector. No increment of 226Ra and 228Ra was observed for increasing PG doses. Average values found for 226Ra and 228Ra were respectively 37 Bq kg-1 and 57 Bq kg-1. The results showed that the increasing PG doses in the specific conditions of the experiment did not cause a significant increment of radionuclides.

  20. Investigation of natural radioactivity levels in water around Kadugli, Sudan

    International Nuclear Information System (INIS)

    Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for 238U, 226Ra, 222Rn, and 232Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: -1 for 238U, 226Ra, 222Rn, and 232Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, -1) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr-1 except in one groundwater sample with an associated dose of 0.7 mSv yr-1

  1. Radioactivity in Zircon from Jos, Central Nigeria

    International Nuclear Information System (INIS)

    Mining and processing of zircon along with other minerals, generally for export purposes, have been taking place in Jos, central Nigeria, for several decades. Over the years, there has been increasing concern about the radiological impact resulting from these activities. A previous assessment in the vicinity of processing areas reported an annual dose of 50 mSv which by far exceeds the 1 mSv dose limit for members of the public. In the study, the activity concentrations of 238U and 232Th in 28 samples of zircon from Jos were determined using neutron activation analysis. The results gave concentrations of 466 μg/g (5.75 Bq/g) for 238U and 7054 μg/g (28.62 Bq/g) for 232Th. These results complement the results of earlier assessments and may assist in the proper management of these activities and the choice and implementation of appropriate protective measures. (author)

  2. Transfer of Radioactivity in the Treatment of Wastewater by Phosphate

    International Nuclear Information System (INIS)

    Radionuclides of natural, terrestrial origin are ubiquitous in the environment and contribute significantly to external and internal doses to the population. Of particular importance are the solid radionuclides belonging to the 238U and 232Th series which are present in soil and rocks. The aim of this work was to study the transfer of 238U and 232Th during the treatment of wastewater by infiltration percolation through a phosphate bed. To assess radiation dose due to the treated water which is used in agriculture and for the irrigation of gardens in urban areas, these radionuclides have been measured in wastewater, phosphate samples and treated water by using solid state nuclear track detectors. (author)

  3. Determination of naturally occurring radionuclides in selected rocks from Hetaunda area, Central Nepal

    International Nuclear Information System (INIS)

    The specific activities of the naturally occurring radionuclides 238U, 232Th, and 40K were measured in rock samples from the Hetaunda area, central Nepal, by using gamma spectrometry. The specific activities were found to be in the range of 17 - 95 Bq.kg-1 for 238U, 24 - 260 Bq.kg-1 for 232Th and 32 - 541 Bq.kg-1 for 40K. From these data absorbed dose rates in air and annual effective doses were calculated and compared with respective data from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) compilation. The results from our study open the door to the safe applicability of most of the investigated materials as a cheep building material. (author)

  4. Determination of naturally occurring radionuclides in selected rocks from Hetaunda area, central Nepal

    International Nuclear Information System (INIS)

    The specific activities of the naturally occurring radionuclides 238U, 232Th, and 40K were measured in rock samples from the Hetaunda area, central Nepal, using gamma spectrometry. The specific activities were found to be in the range of 17-95 Bq kg-1 for 238U, 24-260 Bq kg-1 for 232Th and 32-541 Bq kg-1 for 40K. From these data absorbed dose rates in air and annual effective doses were calculated and compared with respective data from the UNSCEAR compilation. The results from our study open the door to the safe applicability of most of the investigated materials as a cheep building material. (author)

  5. Mussels (Mytilus galloprovincialis) as a bio-indicator species in radioactivity monitoring of Eastern Adriatic coastal waters.

    Science.gov (United States)

    Krmpotić, Matea; Rožmarić, Martina; Barišić, Delko

    2015-06-01

    Croatian Adriatic coastal waters are systematically monitored within the Mediterranean Mussel Watch Project using mussels (Mytilus galloprovincialis) as a bio-indicator species. The study includes determination of naturally occurring ((7)Be, (40)K, (232)Th, (226)Ra and (238)U), as well as anthropogenic (137)Cs radionuclides. Activity concentrations in dry weight of mussels' soft tissue along the Croatian Adriatic coast are presented, with spatial and seasonal variations given and discussed. Samples were collected in spring and autumn for the period between 2009 and 2013. Radionuclides were determined by gamma-ray spectrometry. Activity concentrations of (7)Be were the highest in spring periods, especially in the areas with significant fresh water discharges. Activity concentrations of (40)K did not vary significantly with season or location. (137)Cs activities were low, while (232)Th, (226)Ra and (238)U activities were mostly below the detection limit of performed gamma-spectrometric measurement.

  6. Radiological characterization of pharmaceutical and cosmetic clays

    International Nuclear Information System (INIS)

    Natural radionuclide activity concentration (235U, 238U, 234U, 230Th, 226Ra, 232Th, 228Th, 228Ra and 40K) in clay materials used for cosmetic and medical purposes was determined by alpha and gamma spectrometry. The activity concentration resulted in the range of 0.71 and 4.42 Bq kg-1 for 235U, 15.1-91.4 and 15.3-81.6 Bq kg-1 for 238U and 234U, respectively, 18.7-72.4 Bq kg-1 for 230Th, 27.6-59.7 for 226Ra, 7.80-55.0 and 8.76-58.1 for 232Th and 228Th, 8.60-66.9 Bq kg-1 for 228Ra and 151.6-1,459 Bq kg-1 for 40K. In an oral treatment, the intake was calculated and for some radionuclides the results were higher than the annual dietary intake. (author)

  7. Solid state track recorder measurements in the poolside critical assembly

    International Nuclear Information System (INIS)

    Fission rate measurements using solid state track recorders (SSTR) have been performed at the PCA. A schematic representation of a cross-section of the PCA is shown. Fission rates were measured in the pressure vessel simulator at the T/4, T/2 and 3T/4 positions and in the void box (VB). SSTR measurements were carried out with 232Th, 235U (bare and cadmium covered), 238U and 237Np fissionable deposits. Midplane only measurements were carried out for 235U and 237Np, while 5 axial locations at 1/4T and 1/2T and 3 axial locations at 3/4T and in the VB were sampled for 232Th and 238U. The HEDL SSTR fission rate measurements reported herein for both configurations together with NBS and CEN/SCK fission chamber measurements will be used to establish absolute and relative fission reaction rates, and ratios for the PCA pressure vessel Benchmark Facility

  8. Ecological transfer of radionuclides and metals to free-living earthworm species in natural habitats rich in NORM

    Energy Technology Data Exchange (ETDEWEB)

    Mrdakovic Popic, Jelena, E-mail: jelena.mrdakovic.popic@umb.no; Salbu, Brit; Skipperud, Lindis

    2012-01-01

    Transfer of radionuclides ({sup 232}Th and {sup 238}U) and associated metals (As, Cd, Pb and Cr) from soil to free-living earthworm species was investigated in a thorium ({sup 232}Th) rich area in Norway. Sampling took place within former mining sites representing the technologically enhanced naturally occurring radioactive materials (TENORM), at undisturbed site with unique bedrock geology representing the naturally occurring radioactive materials (NORM) and at site outside the {sup 232}Th rich area taken as reference Background site. Soil analysis revealed the elevated levels of investigated elements at NORM and TENORM sites. Based on sequential extraction, uranium ({sup 238}U) and cadmium (Cd) were quite mobile, while the other elements were strongly associated with mineral components of soil. Four investigated earthworm species (Aporrectodea caliginosa, Aporrectodea rosea, Dendrodrilus rubidus and Lumbricus rubellus) showed large individual variability in the accumulation of radionuclides and metals. Differences in uptake by epigeic and endogeic species, as well as differences within same species from the NORM, TENORM and Background sites were also seen. Based on total concentrations in soil, the transfer factors (TF) were in ranges 0.03-0.08 and 0.09-0.25, for {sup 232}Th and {sup 238}U, respectively. TFs for lead (Pb), chromium (Cr) and arsenic (As) were low (less than 0.5), while TFs for Cd were higher (about 10). Using the ERICA tool, the estimated radiation exposure dose rate of the earthworms ranged from 2.2 to 3.9 {mu}Gy/h. The radiological risk for investigated earthworms was low (0.28). The obtained results demonstrated that free-living earthworm species can survive in soil containing elevated {sup 232}Th and {sup 238}U, as well As, Cd, Pb and Cr levels, although certain amount of radionuclides was accumulated within their bodies. The present investigation contributes to general better understanding of complex soil-to-biota transfer processes of

  9. Gamma-spectrometric measurement of radioactivity in agricultural soils of the Lombardia region, northern Italy

    International Nuclear Information System (INIS)

    This work is part of a wider monitoring project of the agricultural soils in Lombardia, which aims to build a database of topsoil properties and the potentially toxic elements, organic pollutants and gamma emitting radionuclides that the topsoils contain. A total of 156 agricultural soils were sampled according to the LUCAS (Land Use/Cover Area frame statistical Survey) standard procedure. The aim was to provide a baseline to document the conditions present at the time of sampling. The results of the project concerning soil radioactivity are presented here. The aim was to assess the content of 238U, 232Th, 137Cs and 40K by measuring soil samples by gamma spectrometry. 238U, 232Th and 40K activities range 24–231, 20–70, and 242–1434 Bq kg−1 respectively. The geographic distribution of 238U reflects the geophysical framework of the Lombardia region: the soils with high content of uranium are distributed for the most part in the South Alpine belt, where the presence of magmatic rocks is widespread. These soils show an higher activity of 238U than of 232Th. The 238U activities become lower than 232Th when soils are located in the plain, originating from basic sedimentary rocks. 137Cs activity ranges 0.4–86.8 kBq m−2. The lowest activity of 137Cs is in the plain, whereas the highest is in the North on soils kept as lawn or pasture. The 137Cs activity of some samples suggests the presence of accumulation processes that lead to 137Cs enriched soils. This is the first survey of gamma emitting radionuclides in Lombardia that is based on the LUCAS standard sampling. The results from this monitoring campaign are important for the human radiation exposure and provide the zero point, which will be useful for assessing future effects due to external factors such as human activities. - Highlights: • A monitoring campaign of agricultural soils was carried out in Lombardia, Italy. • 156 topsoils were sampled according to the European standard procedure LUCAS.

  10. Natural radioactivity measurements in agricultural soil, fertilizer and crops in some specific areas of Kingdom of Saudi Arabia

    Energy Technology Data Exchange (ETDEWEB)

    Latif, Shaikh Abdul; Kinsara, Abdulraheem Abdulrahman; Molla, Nurul Islam; Nassef, Mohamed Hamed [King Abdulaziz Univ., Jeddah (Saudi Arabia). Faculty of Engineering

    2014-09-01

    High Purity Germanium (HPGe) detector gamma-ray spectrometry with 500 cc Marinelli beaker geometry was used for radioactivity measurement in some specific areas of Kingdom of Saudi Arabia (KSA). The detection limits of {sup 210}Pb, {sup 238}U, {sup 226}Ra, {sup 232}Th and {sup 40}K in soil, fertilizers, and vegetables lie mostly below 1 Bq/kg. The activity concentrations of {sup 238}U and {sup 226}Ra in local phosphate fertilizers were measured in the range of 236.8-879.0 Bq/kg and 101.5-297.0 Bq/kg, respectively. The respective activity concentrations of {sup 238}U and {sup 226}Ra measured in one charge of German phosphate fertilizer are in the range of 552.7-790.0 Bq/kg and 280.6-317.0 Bq/kg. The activity concentrations of {sup 232}Th are assessed to have maximum values up to 2.24 Bq/kg in locally manufactured phosphate fertilizers. Local urea exhibited concentration level (Bq/kg) of {sup 210}Pb, {sup 238}U, {sup 226}Ra, {sup 232}Th and {sup 40}K below the detection limit. Mean values of activity concentrations of {sup 238}U in agricultural soil of Wadi Fatima, Taif, Hada Al-Sham, Madina City and Abyar Al-MashiMadina are 21.7 ± 3.24, 38.2 ± 4.1, 17.6 ± 2.1, 34.3 ± 3.5 and 32.7 ± 2.4 Bq/kg, respectively. The respective mean of {sup 226}Ra activity concentrations in those areas are 12.16 ± 1.16, 20.2 ± 1.33, 11.21 ± 0.4, 21.4 ± 1.7 and 21.0 ± 1.22 Bq/kg. The specific activity of {sup 232}Th in the respective areas has been measured as 12.6 ± 1.3, 25.3 ± 0.8, 11.5 ± 0.9, 20.4 ± 2.4 and 20.0 ± 1.2 Bq/kg. Activity concentrations of {sup 210}Pb, {sup 238}U, {sup 226}Ra and {sup 232}Th in the vegetable samples are mostly found in the range of 0.37 Bq/kg to 37.8 Bq/kg. The {sup 40}K specific activity lies in the range of 44.4-196 Bq/kg. The calculated absorbed dose rates in the representative locations are 24.07-53.28 nGy/h. (orig.)

  11. U-Th-Ra variations in Himalayan river sediments (Gandak river, India): Weathering fractionation and/or grain-size sorting?

    Science.gov (United States)

    Bosia, Clio; Chabaux, François; Pelt, Eric; France-Lanord, Christian; Morin, Guillaume; Lavé, Jérôme; Stille, Peter

    2016-11-01

    Understanding the origin of U-Th-Ra variations in the Ganga river sediments is a prerequisite for correctly using U-series nuclides to constrain the sediment transport times in Himalayan rivers. For this purpose, U, Th, and Ra concentrations, along with 238U-234U-230Th-226Ra radioactive disequilibria, were analyzed in bank, bedload and suspended sediments from the Gandak river, one of the main tributaries of the Ganga river. The data confirm that U and Th budgets of the Himalayan sediments are significantly influenced by minor resistant minerals, such as zircon, garnet and Ti-bearing minerals, the dissolution of which required the use of a high-pressure acid digestion process. Most importantly, the results indicate that the variations in (238U/232Th) and (230Th/232Th) activity ratios and 238U-234U-230Th-226Ra disequilibria in sediments along the river alluvial plain mainly reflect modifications in the mineralogical and grain-size compositions rather than the degree of weathering during transport. The (238U/232Th) and (230Th/232Th) activity ratios in the bank and bed sediments are related to variations in the minor primary minerals strongly enriched in U and Th (i.e., zircon, REE-bearing minerals and Ti-bearing minerals), whereas the activity ratios in the suspended load are related to variations in the proportions of clay, Fe-oxyhydroxides and the silt-sand fraction, which contains U- and Th-bearing minor minerals. The data also indicate that 238U-234U-230Th-226Ra disequilibria are strongly influenced by secondary mineral phases: the 230Th budget is likely mainly controlled by Fe-oxyhydroxides, and the 226Ra budget is likely mainly controlled by clay minerals. Therefore, the variations in the 238U-234U-230Th-232Th system in the sediments of the Gandak river cannot simply be interpreted as the result of fractionation due to chemical transformation of the bulk sediment during its transport within the alluvial plain and/or the result of radioactive decay. Consequently

  12. Soudan Low Background Counting Facility (SOLO)

    International Nuclear Information System (INIS)

    The Soudan Low Background Counting Facility (SOLO) has been in operation at the Soudan Mine, MN since March 2003. In the past two years, we have gamma-screened samples for the Majorana, CDMS and XENON experiments. With individual sample exposure times of up to two weeks we have measured sample contamination down to the 0.1 ppb level for 238U / 232Th, and down to the 0.25 ppm level for 40K

  13. Characterization of the low-background gamma spectrometer at INSTEC for environmental radioactivity studies

    International Nuclear Information System (INIS)

    The capability of Low-Background Gamma Spectrometer (LBGS) at InSTEC for environmental proposes is studied. Fifty three γ-lines were fixed in the LBGS background spectrum. The Minimum Detectable Activities for 210Pb, 238U, 226Ra, 137Cs, 232Th and 40K were calculated using a Monte Carlo simulated detector volumetric efficiency. The radionuclide activities in marine sediment standard were determined by absolute and relative methods for validation. (Author)

  14. Translation of selected papers published in Nuclear Constants, No. 3(57), Moscow 1984

    International Nuclear Information System (INIS)

    The document contains the English translation of 6 papers selected for the nuclear data interest, (mainly the determination and the evaluation of the fast fission cross sections of 232Th, 235U, 238U, 237Np, 243Am) which were published in ''Topics in Atomic Science and Technology'', Series Nuclear Constants, No. 3(57), Moscow (1984). The original report was distributed as INDC(CCP)-240/G. Refs, figs and tabs

  15. NATURAL RADIOACTIVITY IN SOME BUILDING MATERIALS USING A GAMMA-RAY SPECTROMETER

    OpenAIRE

    AKKURT, Iskender; Betül MAVİ

    2011-01-01

    The main reason for the natural radioactivity in the earth is decay series of 40K, 238U and 232Th radionuclides. Because all building materials are soil product, they contain these radionuclides as natural so that building materials have different amounts of radioactivity. In this study the concentrations of natural radioactivity levels of the commonly used natural building materials in Isparta region have been determined. The samples have been analysed using a NaI(Tl) ƒ×-ray spectrometer sy...

  16. Review of international normatives for natural radioactivity determination in building materials

    OpenAIRE

    Mossini Eros; Macerata Elena; Giola Marco; Mariani Mario

    2015-01-01

    Anthropogenic activities, such as high-altitude flights and living in buildings, have enhanced the public exposure to natural radiation. In particular, 40K and radionuclides belonging to 232Th and 238U decay chains are present even in building materials, and they may be considered as partially responsible for the effective dose coming from natural radioactivity. Scientists and governments have devoted great attention to the evaluation of the effects produced on the public by naturally occurri...

  17. Assessments of radioactivity concentration of natural radionuclides and radiological hazard indices in sediment samples from the East coast of Tamilnadu, India with statistical approach.

    Science.gov (United States)

    Ravisankar, R; Chandramohan, J; Chandrasekaran, A; Prince Prakash Jebakumar, J; Vijayalakshmi, I; Vijayagopal, P; Venkatraman, B

    2015-08-15

    This paper reports on the distribution of three natural radionuclides (238)U, (232)Th and (40)K in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a NaI(Tl) detector based γ-spectrometry. The mean activity concentration is ⩽2.21, 14.29 and 360.23Bqkg(-1) for (238)U, (232)Th and (40)K, respectively. The average activity of (232)Th, (238)U and (40)K is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of (238)U, (232)Th and (40)K to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (Hex) internal hazard index (Hin), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended values. Therefore, coastal sediments do not to pose any significant radiological health risk to the people living in nearby areas along East coast of Tamilnadu. The data obtained in this study will serve as a baseline data in natural radionuclide concentration in sediments along the coastal East coast of Tamilnadu. PMID:26036177

  18. FFTF (FAST FLUX TEST FACILITY) REACTOR CHARACTERIZATION PROGRAM ABSOLUTE FISSION RATE MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    FULLER JL; GILLIAM DM; GRUNDL JA; RAWLINS JA; DAUGHTRY JW

    1981-05-01

    Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.

  19. FFTF (Fast Flux Test Facility) Reactor Characterization Program: Absolute Fission-rate Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, J.L.; Gilliam, D.M.; Grundl, J.A.; Rawlins, J.A.; Daughtry, J.W.

    1981-05-01

    Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.

  20. Radionuclides and Radiation Indices of High Background Radiation Area in Chavara-Neendakara Placer Deposits (Kerala, India)

    OpenAIRE

    Mary Thomas Derin; Perumal Vijayagopal; Balasubramaniam Venkatraman; Ramesh Chandra Chaubey; Anilkumar Gopinathan

    2012-01-01

    The present paper describes a detailed study on the distribution of radionuclides along Chavara - Neendakara placer deposit, a high background radiation area (HBRA) along the Southwest coast of India (Kerala). Judged from our studies using HPGe gamma spectrometric detector, it becomes evident that Uranium ((238)U), Thorium ((232)Th) and Potassium ((40)K) are the major sources for radioactivity prevailing in the area. Our statistical analyses reveal the existence of a high positive correlation...

  1. Distribution, enrichment and principal component analysis for possible sources of naturally occurring and anthropogenic radionuclides in the agricultural soil of Punjab state, India.

    Science.gov (United States)

    Kumar, Ajay; Joshi, Vikram M; Mishra, Manish K; Karpe, Rupali; Rout, Sabyasachi; Narayanan, Usha; Tripathi, Raj M; Singh, Jaspal; Kumar, Sanjeev; Hegde, Ashok G; Kushwaha, Hari S

    2012-06-01

    Enrichment factor (EF) of elements including geo-accumulation indices for soil quality and principal component analysis (PCA) were used to identify the contributions of the origin of sources in the studied area. Results of (40)K, (137)Cs, (238)U and (232)Th including their decay series isotopes in the agricultural soil of Mansa and Bathinda districts in the state of Punjab were presented and discussed. The measured mean radioactivity concentrations for (238)U, (232)Th and (40)K in the agricultural soil of the studied area differed from nationwide average crustal abundances by 51, 17 and 43 %, respectively. The sequence of the EFs of radionuclides in soil from the greatest to the least was found to be (238)U > (40)K > (226)Ra > (137)Cs > (232)Th > (228)Ra. Even though the enrichment of naturally occurring radionuclides was found to be higher, they remained to be in I(geo) class of '0', indicating that the soil is uncontaminated with respect to these radionuclides. Among non-metals, N showed the highest EF and belonged to I(geo) class of '2', indicating that soil is moderately contaminated due to intrusion of fertiliser. The resulting data set of elemental contents in soil was also interpreted by PCA, which facilitates identification of the different groups of correlated elements. The levels of the (40)K, (238)U and (232)Th radionuclides showed a significant positive correlation with each other, suggesting a similar origin of their geochemical sources and identical behaviour during transport in the soil system. PMID:21893521

  2. Assessment of natural radioactivity levels in rocks and their relationships with the geological structure of Johor state, Malaysia.

    Science.gov (United States)

    Alnour, I A; Wagiran, H; Ibrahim, N; Hamzah, S; Elias, M S; Laili, Z; Omar, M

    2014-01-01

    The distribution of natural radionuclides ((238)U, (232)Th and (40)K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of (238)U, (232)Th and (40)K activity concentrations (67±6, 85±7 and 722±18 Bg kg(-1), respectively) were observed in the granite rock. The lowest concentrations of (238)U and (232)Th (2±0.1 Bq kg(-1) for (238)U and 2±0.1 Bq kg(-1) for (232)Th) were observed in gabbro rock. The lowest concentration of (40)K (45±2 Bq kg(-1)) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg(-1). The highest value of radium equivalent in the present study (239±17 Bq kg(-1)) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h(-1). The effective dose ranged from 5 to 138 μSv h(-1). The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed.

  3. Reference material for natural radionuclides in glass designed for underground experiments

    OpenAIRE

    Povinec, P.; PHAM M. K.; Busto, J.; Cerna, C.; Degering, D.; Y. Hamajima; Holy, K.; Hult, Mikael; Jeskovsky, M.; Koehler, M; Kovacik, A.; Laubenstein, Matthias; Loaiza, P.; Mamedov, F.; Marquet, C.

    2015-01-01

    A reference material designed for the determination of natural radionuclides in solid samples (glass pellets) is described and the results of certification are presented. The material has been certified for 7 natural radionuclides (40K, 226Ra, 228Ra, 228Th, 232Th, 235U and 238U). An information value is given for 210Pb. Radon (222Rn) emanation experiments showed results comparable within participating laboratories, however, the number of data and precision was too low to carry out a certifica...

  4. The formation and decay of superheavy nuclei produced in $^{48}Ca$-induced reactions

    OpenAIRE

    Kumar, Sushil; Balasubramaniam, M.; Raj K Gupta; Munzenberg, G.; Scheid, W.

    2011-01-01

    The formation of superheavy nuclei in $^{48}Ca+^{232}Th$, $^{238}U$, $^{242,244}Pu$ and $^{248}Cm$ reactions and their subsequent decay are studied within the quantum mechanical fragmentation theory (QMFT) and the QMFT based preformed cluster-decay model (PCM) of Gupta and collaborators. According to QMFT, all these $^{48}Ca$-induced reactions are cold fusion reactions with relative excitation energies larger than for the $Pb$-induced cold fusion reactions and smaller than for the lighter bea...

  5. Analysis for the radionuclides of the natural uranium and thorium decay chains with special reference to uranium mine tailings

    International Nuclear Information System (INIS)

    A detailed review is made of the experimental techniques that are available, or are in the process of development, for the determination of 238U, 235U, 234U, 231Pa, 232Th, 230Th, 228Th, 228Ra, 226Ra, 223Ra, 210Po and 210Pb. These products of the uranium and thorium decay chains are found in uranium mine tailings. Reference is also made to a procedure for the selective phase extraction of mineral phases from uranium mine tailings

  6. Isoscaling and fission modes in the yields of the Kr and Xe isotopes from photofission of actinides

    Science.gov (United States)

    Drnoyan, J.; Zhemenik, V. I.; Mishinsky, G. V.

    2016-05-01

    Yields of Kr and Xe isotopes in photofission of 232Th, 238U, 237Np, 244Pu, 243Am, and 248Cm were tested for isoscaling dependence. Isoscaling for Kr is revealed. For Xe, isoscaling is found to be affected by the STI and STII fission modes governed by the N = 82 and N = 88 neutron shells. The work was performed at the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (JINR).

  7. Assessment of natural radionuclide levels in Pakistani foodstuffs and associated radiation doses

    International Nuclear Information System (INIS)

    A comprehensive study for the assessment of natural radionuclides (40K, 238U, 226Ra, 228Ra, and 232Th) in Pakistani food items (fruits, seasonal vegetables, beef, mutton, poultry meat and eggs) and drinks samples (milk, tap water and soft drinks) was carried out in Pakistan using HPGe based high resolution gamma spectrometry. All the food items and drink samples showed detectable 40K activity, however, most of the other natural radionuclides in solid food were found to have contents below the minimum detectable activity (MDA). The range of 40K activity was found to be 0.02 to 110.5 Bq kg-1 for solid food and drink samples. The cumulative average value of 238U, 226Ra, 228Ra and 232Th were found to be 0.07, 0.03, 0.06 and 0.06 Bq kg-1 in fruits, vegetables, meat and egg samples respectively. In all milk and water based drinks the respective measured values of the mean activity of 238U, 226Ra, 228Ra and 232Th were 0.16, 0.06, 0.07 and 0.05 Bq kg-1. The annual ingestion/intakes of 40K 238U, 226Ra, 228Ra and 232Th were found to be only 0.06%, 0.007%, 0.02%, 0.03% and 0.05% of the Annual Limits on Intakes (ALIs) of these radionuclides as specified by IAEA, which shows that their contribution in Pakistani diet does not pose any significant radiological health problem. (author)

  8. Natural Radioactivity in Soil and Water from Likuyu Village in the Neighborhood of Mkuju Uranium Deposit

    OpenAIRE

    Mohammed, Najat K.; Mazunga, Mohamed S.

    2013-01-01

    The discovery of high concentration uranium deposit at Mkuju, southern part of Tanzania, has brought concern about the levels of natural radioactivity at villages in the neighborhood of the deposit. This study determined the radioactivity levels of 30 soil samples and 20 water samples from Likuyu village which is 54 km east of the uranium deposit. The concentrations of the natural radionuclides 238U, 232Th, and 40K were determined using low level gamma spectrometry of the Tanzania Atomic Ener...

  9. Radon-222 dose rates to burrowing mammals

    OpenAIRE

    Beresford, N.A.; Barnett, C.L.; Potter, E. D.; Vives I Batlle, J.; Barlow, T.S.; Copplestone, D.

    2011-01-01

    Estimates of absorbed dose rates as a consequence of exposure of wildlife to natural background radionuclides are required to put results of assessments conducted for releases of radionuclides from licensed sites into context. There have been recent review papers in which estimated dose rates to marine, freshwater and terrestrial wildlife (specifically the ICRP Reference Animals and Plants (ICRP 2008)) from 40K and radionuclides in the 238U and 232Th series have been presented (Beresford et a...

  10. Preliminary survey of outdoor gamma dose rates in Lesvos Island (Greece).

    Science.gov (United States)

    Petalas, Anastasios B; Vogiannis, Efstratios; Nikolopoulos, Dimitrios; Halvadakis, Constantinos P

    2005-01-01

    This study reports the first attempt to record the radioactive background due to gamma radiation in Lesvos Island (Greece). The study reports the results from 335 outdoor total gamma effective dose rate measurements conducted using GPS navigation and a Geiger-Muller detector (Bicron, Micro Sievert) on the whole surface of the island together with a digital map produced by appropriate mapping GIS programme. The study also reports the measurements of outdoor gamma dose rates due to the 238U, 232Th and 40K radionuclides as estimated via in situ gamma-ray spectrometry measurements performed at 26 sites using a 3 x 3 inch NaI (thallium activated) portable detector. The results from the outdoor total gamma effective dose rates range between 0.0023 and 0.28 microSv h(-1). The highest outdoor total gamma effective dose rates (0.013-0.28 microSv h(-1)) were detected in the northeastern part of the island and the intermediate rates (0.066-0.13 microSv h(-1)) in the central region. The outdoor gamma dose rates due to 238U, 232Th and 40K radionuclides range between 1.7 +/- 0.8 and 154 +/- 7 nGy h(-1) with an average of 86 +/- 6 nGy h(-1). The average contribution of each of the examined radionuclides (238U, 232Th and 40K) to the total gamma dose rate was found to be equal to 12 +/- 4% for 238U, 58 +/- 6% for 232Th and 29 +/- 7% for 40K, respectively. PMID:15728423

  11. Determination of uranium and thorium isotope ratios by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Measurements conditions were selected and a procedure was proposed for determining the 234U/238U and 230Th/232Th isotope ratios using an ELEMENT single-channel double-focusing inductively coupled plasma mass spectrometer. The procedure was tested in analyzing bottom sediments from Lake Baikal with the extraction preconcentration of uranium and thorium. The accuracy of the procedure was verified using certified reference materials and a model solution by comparing the results obtained with the data of α spectrometry

  12. Natural gamma radioactivity and of {sup 137} Cs in soil of the Chimaltitan municipality, Jalisco, Mexico; Radiactividad gamma natural y del {sup 137} Cs en suelo del Municipio de Chimaltitan, Jalisco, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garay, A.; Mireles, F.; Quirino, L.L.; Davila, J.I.; Rios, C.; Lugo, J.F.; Soriano, J.M.; Angoli, A. [UAEN-Universidad Autonoma de Zacatecas, Cipres 10, Frac. La Penuela, 98000 Zacatecas (Mexico)]. e-mail: albinogaray@hotmail.com.mx

    2003-07-01

    With the purpose of determining the activity due to the natural presence of the {sup 226} Ra, {sup 232} Th, {sup 40} K and {sup 137} Cs in soil samples, of the municipality of Chimaltitan Jalisco. A set of these samples was measured in a gamma ray spectrometric system based on a High-purity Germanium detector. It is well-known that approximately 87% of the dose of the received radiation by the population is due to sources of natural radiation and 13% of the anthropogenic radiation. The gamma radiation comes mainly from the {sup 40} K and of those radionuclides of the series of radioactive decay of {sup 238} U and {sup 232} Th that its find dispersed thoroughly in the terrestrial crust. In this work its were analyzed twenty-two soil samples. It is enlarged the activity characterization for the radioisotopes of {sup 226} Ra {sup 232} Th, {sup 40} K and {sup 137} Cs. (Author)

  13. Study on the primordial concentration of radionuclides in the soil samples of Pachamali Hills,Tiruchirappalli district,Tamil Nadu

    International Nuclear Information System (INIS)

    Every living organism on this planet is constantly exposed to naturally occurring ionizing radiations, which are referred to as background radiation or natural radiation. Exposure of this ionizing radiation due to naturally occurring radionuclides present in soil and rocks is unavoidable. 238U, 232Th and 40K are the major radionuclides present abundantly in nature. These radionuclides vary in concentration over different areas due topographical, geographical, geochemical conditions of the areas concerned. Present study has been undertaken with the aim to generate baseline data on the radiation profile on the background radiation of Pachamalai Hill environment located in Tiruchirappalli dist. Totally 60 soil samples have been collected from six major sampling stations and processed and analysed using NaI(TI) gamma ray spectrometer. The activity of 232Th has been found to be varied from 23.12 to 103.4 Bqkg-1. The activity of 238U has been found to be varied form 10.64 to 47.25 Bqkg-1 and the activity of 40K varies from 120 to 324.12 Bqkg-1. The depth profile study also has been carried out. In the case of depth profile study concentration of 238U and 232Th has been found to decrease with depth in soil. However, the activity due to 40K remains more or less uniform. The mean absorbed dose rate due to primordial radionuclides is found to be 59.7 nGy h-1. (author)

  14. Natural Radioactivity in Soil and Water from Likuyu Village in the Neighborhood of Mkuju Uranium Deposit

    Directory of Open Access Journals (Sweden)

    Najat K. Mohammed

    2013-01-01

    Full Text Available The discovery of high concentration uranium deposit at Mkuju, southern part of Tanzania, has brought concern about the levels of natural radioactivity at villages in the neighborhood of the deposit. This study determined the radioactivity levels of 30 soil samples and 20 water samples from Likuyu village which is 54 km east of the uranium deposit. The concentrations of the natural radionuclides 238U, 232Th, and 40K were determined using low level gamma spectrometry of the Tanzania Atomic Energy Commission (TAEC Laboratory in Arusha. The average radioactivity concentrations obtained in soil samples for 238U (51.7 Bq/kg, 232Th (36.4 Bq/kg, and 40K (564.3 Bq/kg were higher than the worldwide average concentrations value of these radionuclides reported by UNSCEAR, 2000. The average activity concentration value of 238U (2.35 Bq/L and 232Th (1.85 Bq/L in water samples was similar and comparable to their mean concentrations in the control sample collected from Nduluma River in Arusha.

  15. Radioactivity levels in soil of salt field area, Kelambakkam, Tamilnadu, India

    Institute of Scientific and Technical Information of China (English)

    R.RAVISANKAR; A.RAJALAKSHMI; P.ESWARAN; V GAJENDIRAN; V.MEENAKSHISUNDRAM

    2007-01-01

    Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer.The activity concentration for 232 Th,238 U and 40 K are ranged from 27.88 to 45.27 Bq/kg,from BDL to 13.30 Bq/kg,and from 135.54 to 381.28 Bq/kg,respectively.The measured activity concentrations for these radionudides were compared with world average activity of soil.The average activity concentration of 232Th in the present study is 1.19 times higher than world median value while the activity of 238 U and 40K is found to be lower.The absorbed dose rates due to these radionuclides、were calculated.The average absorbed gamma dose rate due to the presence of 232Th,238U and 40K in soil samples is 36.99 nGy-h(-1).These results indicate no radiological anomaly.The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.

  16. Preliminary Study of Natural Radioactivity in the Lake Bosumtwi Basin

    Directory of Open Access Journals (Sweden)

    Simon Adu

    2011-08-01

    Full Text Available The concentrations of 238U, 232Th, and 40K in water from Lake Bosumtwi and bore-holes in selected towns around the Bosumtwi basin of the Ashanti region of Ghana have been determined. The concentrations were determined for water samples from 24 boreholes and 12 points across the lake using a High-Purity Germanium (HPGe (γ-ray spectrometry. The water samples from the lake were found to contain acceptable levels of radionuclides with mean activity concentrations of 7.9, 89.7 and 0.6 mBq/L for 238U, 40K, and 232Th, respectively. The water samples from the boreholes recorded mean activity concentrations of 7.7, 85.5, and 3.3 mBq/L for 238U, 40K and 232Th, respectively. The annual effective dose calculated for the lake varied from 0.244 to 1.121 μSv with an average of 0.763 μSv and that calculated for the boreholes varied from 0.296 to 2.173 μSv with an average of 1.166 μSv. The radionuclides concentrations in water from the bore-holes and that of the lake, which serve as sources of water supply to the surrounding communities are negligible and pose no radiological hazards to the public.

  17. Clay Mineral: Radiological Characterization

    Science.gov (United States)

    Cotomácio, J. G.; Silva, P. S. C.; Mazzilli, B. P.

    2008-08-01

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and 40K in these clay minerals. The objective of this work is to determine the concentrations of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay. Measurement for the determination of 238U and 232Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for 226Ra, 228Ra, 210Pb and 40K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906±340 Bq kg-1 for 40K, 40±9 Bq kg-1 for 226Ra, 75±9 Bq kg-1 for 228Ra, 197±38 Bq kg-1 for 210Pb, 51±26 Bq kg-1 for 238U and 55±24 Bq kg-1 for 232Th, considering both kinds of clay.

  18. Assay methods for U-238, Th-232, and Pb-210 in lead and calibration of Bi-210 bremsstrahlung emission from lead

    CERN Document Server

    Orrell, John L; Arnquist, Isaac J; Eggemeyer, Tere A; Glasgow, Brian D; Hoppe, Eric W; Keillor, Martin E; Morley, Shannon M; Myers, Allan W; Overman, Cory T; Shaff, Sarah M; Thommasson, Kimbrelle S

    2015-01-01

    Assay methods for measuring 238U, 232Th, and 210Pb concentrations in refined lead are presented. The 238U and 232Th concentrations are determined using isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) after anion exchange column separation of dissolved lead samples. The 210Pb concentration is inferred through {\\alpha}-spectroscopy of a daughter isotope, 210Po, after chemical precipitation separation on dissolved lead samples. Subsequent to the 210Po {\\alpha}-spectroscopy assay, a method for evaluating 210Pb concentrations in solid lead samples was developed via measurement of bremsstrahlung radiation from \\b{eta}-decay of a daughter isotope, 210Bi, by employing a 14-crystal array of high purity germanium (HPGe) detectors. Ten sources of refined lead were assayed. The 238U concentrations were <34 microBq/kg and the 232Th concentrations ranged <0.6-15 microBq/kg, as determined by the ICP-MS assay method. The 210Pb concentrations ranged from ~0.1-75 Bq/kg, as inferred by the 210Po ...

  19. Radioactivity measurements in moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis) samples collected from Marmara region of Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Belivermis, Murat, E-mail: belmurat@istanbul.edu.t [Istanbul University, Faculty of Science, Department of Biology, 34134 Vezneciler, Istanbul (Turkey); Cotuk, Yavuz, E-mail: cotukyav@istanbul.edu.t [Istanbul University, Faculty of Science, Department of Biology, 34134 Vezneciler, Istanbul (Turkey)

    2010-11-15

    The present study was conducted to compare the {sup 137}Cs, {sup 40}K, {sup 232}Th, and {sup 238}U activity concentrations in epigeic moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis). The activity levels in 37 moss and 38 lichen samples collected from the Marmara region of Turkey were measured using a gamma spectrometer equipped with a high purity germanium (HPGe) detector. The activity concentrations of {sup 137}Cs, {sup 40}K, {sup 232}Th, and {sup 238}U in the moss samples were found to be in the range of 0.36-8.13, 17.1-181.1, 1.51-6.17, and 0.87-6.70 Bq kg{sup -1} respectively, while these values were below detection limit (BDL)-4.32, 16.6-240.0, 1.32-6.47, and BDL-3.57 Bq kg{sup -1} respectively in lichen. The average moss/lichen activity ratios of {sup 137}Cs, {sup 40}K, {sup 232}Th, and {sup 238}U were found to be 1.32 {+-} 0.57, 2.79 {+-} 1.67, 2.11 {+-} 0.82, and 2.19 {+-} 1.02, respectively. Very low {sup 137}Cs concentrations were observed in moss and lichen samples compared to soil samples collected from the same locations in a previous study. Seasonal variations of the measured radionuclide activities were also examined in the three sampling stations.

  20. Activity concentrations of natural radionuclide levels in well waters of Ago Iwoye, Nigeria

    International Nuclear Information System (INIS)

    Natural Radioactivity, though natural requires concentration monitoring, especially for the health/ environmental checks of the populace. Materials and Methods; The activity concentrations of 40K, 238U and 232Th in the waters from wells with depths ranging between 141.0 214.0 feet were randomly sampled and determined from 20 locations in Ago-Iwoye town in South Western, Nigeria. Results: The activity concentrations obtained were in the ranges of (9.9-50.9)Bq/kg with mean value of (25.1±10.7) Bq/kg for 40K, (BDL-15.0) Bq/kg with mean value of (1.2±3.2) Bq/kg for 238U and (BDL-6.2) Bq/kg with mean value of (1.6±1.7) Bq/kg for 232Th. Conclusion: According to the results obtained for the activity concentrations from 20 well water samples in Ago Iwoye, Southwestern, Nigeria it was observed that the V40K, 238U and 232Th values were still within the tolerance level indicating minimal radiological health burden on the human populace and the environment.