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Sample records for characteristics 238u 232th

  1. 238U, 234U and 232Th in seawater

    International Nuclear Information System (INIS)

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

    1986-01-01

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

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

    International Nuclear Information System (INIS)

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

    2001-01-01

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

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  4. 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.)

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

    International Nuclear Information System (INIS)

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

    2000-01-01

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

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

    International Nuclear Information System (INIS)

    Sabam Parsaoran Situmorang; Harpasis Selamet Sanusi; June Mellawati

    2011-01-01

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

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

    International Nuclear Information System (INIS)

    Alnour, I.A.

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    Simutkin, V.D.

    2008-01-01

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

  9. 232-Th and 238-U radioactive contaminations of sediments along the South China Sea of East Coast Peninsular Malaysia by INAA

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  10. Resonance Region Covariance Analysis Method and New Covariance Data for Th-232, U-233, U-235, U-238, and Pu-239

    International Nuclear Information System (INIS)

    Leal, Luiz C.; Arbanas, Goran; Derrien, Herve; Wiarda, Dorothea

    2008-01-01

    Resonance-parameter covariance matrix (RPCM) evaluations in the resolved resonance region were done for 232Th, 233U, 235U, 238U, and 239Pu using the computer code SAMMY. The retroactive approach of the code SAMMY was used to generate the RPCMs for 233U, 235U. RPCMs for 232Th, 238U and 239Pu were generated together with the resonance parameter evaluations. The RPCMs were then converted in the ENDF format using the FILE32 representation. Alternatively, for computer storage reasons, the FILE32 was converted in the FILE33 cross section covariance matrix (CSCM). Both representations were processed using the computer code PUFF-IV. This paper describes the procedures used to generate the RPCM with SAMMY.

  11. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-03-15

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

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

    Science.gov (United States)

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

    2005-01-01

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

  14. {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)

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

    Directory of Open Access Journals (Sweden)

    Chiba Satoshi

    2013-03-01

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

  16. 238U-230Th radioactive disequilibria in the volcanic products from Izu arc volcanoes, Japan

    International Nuclear Information System (INIS)

    Kurihara, Yuichi; Takahashi, Masaomi; Sato, Jun

    2007-01-01

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

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

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

    International Nuclear Information System (INIS)

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

    2017-01-01

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

  19. 230Th-238U disequilibria in historical lavas from Iceland

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  20. 232Th/238U in a uranium mobility estimate in an agricultural area in the municipality of Pedra-Pernambuco - Brazil

    International Nuclear Information System (INIS)

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

    2011-01-01

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

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

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

    International Nuclear Information System (INIS)

    Lancman, H.

    1981-02-01

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

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

    International Nuclear Information System (INIS)

    Shi Jinhua; Chen Changhua

    1989-01-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

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

    International Nuclear Information System (INIS)

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

    1984-01-01

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-11-01

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

  12. 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.

  13. Development of sequential analytical method for the determination of U-238, U-234, Th-232, Th-230, Th-228, Ra-226 and Ra-228 and its application in mineral waters

    International Nuclear Information System (INIS)

    Costa Lauria, D. da.

    1986-01-01

    A sequential analytical method for the determination of U-238, U-234, Th-232, Th-230, Th-228, Ra-226 and Ra-228 in environmental samples and applied to the analysis of mineral waters is studied. Thorium isotopes are coprecipitated with lanthanium fluoride before counting in alpha spectrometer, the uranium isotopes are determined by alpha spectrometry following extraction with TOPO onto a polymenic membrane. Radium-226 is determined with the radom emanation technique. (M.J.C.) [pt

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

    International Nuclear Information System (INIS)

    Shiraishi, K.

    1995-01-01

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

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

    International Nuclear Information System (INIS)

    Lancman, H.

    1985-12-01

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  17. 238U-234U-230Th-232Th systematics and the precise measurement of time over the past 500,000 years

    International Nuclear Information System (INIS)

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

    1987-01-01

    We have developed techniques to measure the 230 Th abundance in corals by isotope dilution mass spectrometry. This, coupled with our previous development of mass spectrometric techniques for 234 U and 232 Th measurement, has allowed us to reduce significantly the analytical errors in 238 U- 234 U- 230 Th dating and greatly reduce the sample size. We show that 6x10 8 atoms of 230 Th can be measured to ±30per mille (2 σ) and 2x10 10 atoms of 230 Th to ±2per mille. The time over which useful age data on corals can be obtained ranges from a few years to ≅ 500 ky. The uncertainty in age, based on analytical errors, is ±5 y(2 σ) for a 180 year old coral (3 g), ±44 y at 8294 years and ±1.1 ky at 123.1 ky (250 mg of coral). We also report 232 Th concentrations in corals (0.083-1.57 pmol/g) that are more than two orders of magnitude lower than previous values. Ages with high analytical precision were determined for several corals that grew during high sea level stands ≅ 120 ky ago. These ages lie specifically within or slightly postdate the Milankovitch insolation high at 128 ky and support the idea that the dominant cause of Pleistocene climate change is Milankovitch forcing. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-04-15

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

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

    International Nuclear Information System (INIS)

    Siddeeg, S. M. B.

    2007-06-01

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

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

    Science.gov (United States)

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

    2012-02-01

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

  1. Availability of U-238 and Th-232 present in phosphogypsum used in agriculture: precision and accuracy of the methodology

    International Nuclear Information System (INIS)

    Malheiro, Luciano H.; Saueia, Catia H.R.; Mazzilli, Barbara P.

    2013-01-01

    Phosphogypsum (PG) can be classified as Technologically Enhanced Naturally Occurring Radioactive Material (TENORM), and it is obtained as a residue of the phosphate fertilizer industry. PG presents in its composition radionuclides of the natural U and Th series: mainly Ra-226, Ra-228, Th-232, Pb-210 and Po-210. The Brazilian producers stock the PG in dry stacks, posing risks to the surrounding environment. A possible solution to this problem is to reuse PG in agriculture; however, it is necessary to ensure that the radionuclides present in the PG will not be available to the agricultural products. This study is part of a research project sponsored by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP - 2010-10587-0) entitled 'Availability of metals and radionuclides in tropical soils amended with phosphogypsum', and its objective is to evaluate the reliability of an optimal methodology to determine U-238 and Th-232 in samples of soils amended with PG through percolation with water. The methodology comprises a sequential radiochemical separation of the radionuclides present in the leachate. The UTEVA resin was used for the purification and separation of U-238 and Th-232, and the final activity concentrations were determined by alpha spectrometry. The precision and accuracy of the methodology were checked by measuring standard reference material. The results obtained for the relative error and relative standard deviation varied respectively from 2.34 % to 5.92 % and 6.10 % to 6.21 % for uranium, and from 0.42 % to 3.13 % and 9.68 % to 10.97 % for thorium. (author)

  2. 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)

  3. 238U-234U-230Th chronometry of Fe-Mn crusts: Growth processes and recovery of thorium isotopic ratios of seawater

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  4. 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.

  5. The influence of the nature of soil and plant and pollution on the 238U, 232Th, 222Rn and 220Rn concentrations in various natural honey samples using nuclear track detectors: impact on the adult consumers

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Mortassim, A.

    2009-01-01

    238 U and 232 Th concentrations as well as 222 Rn and 220 Rn α-activities per unit volume were measured in various natural honey samples collected from different regions in Morocco using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). These radionuclides were also measured in soils, plant flowers and nectar solutions corresponding to the honey samples studied. In addition, these radionuclides were measured in different imported honey samples. The measured 238 U, 232 Th, 222 Rn and 220 Rn concentrations ranged from (1.5 ± 0.1) mBq kg -1 to (10.6 ± 0.6) mBq kg -1 , (1.1 ± 0.1) mBq kg -1 to (4.2 ± 0.2) mBq kg -1 , (1.5 ± 0.1) Bq kg -1 to (10.6 ± 0.6) Bq kg -1 and (1.1 ± 0.1) Bq kg -1 to (4.2 ± 0.2) Bq kg -1 for the honey samples studied, respectively. Annual 238 U, 232 Th and 222 Rn intakes by Moroccan adults from the consumption of honey were assessed. The influence of the nature of soil and plant on the 238 U and 232 Th contents of the studied honey samples was investigated. These measurements were completed by an investigation of the 238 U and 232 Th transfer between soils and plant flowers and that between plant flowers and honey, and also by the investigation of the influence of pollution due to different material dusts on 238 U, 232 Th and 222 Rn in the honey samples studied. Committed equivalent doses due to the annual intake of 238 U, 232 Th and 222 Rn were evaluated in the organs of adult members of the Moroccan rural population from the ingestion of the honey samples. The maximum total committed effective dose due to 238 U, 232 Th and 222 Rn from the ingestion of natural honey by the Moroccan rural population was found to be equal to 0.64 μSνy -1 . (author)

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

    International Nuclear Information System (INIS)

    Beckova, V.; Malatova, I.

    2008-01-01

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

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

    CERN Document Server

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

    2002-01-01

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Science.gov (United States)

    Becková, Vera; Malátová, Irena

    2008-01-01

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

  11. Natural Radioactivity of U-238, Th-232 and K-40 in Surface Soil of Baghdad, Nahrain and Al-Mustansiriyah University in Iraq

    International Nuclear Information System (INIS)

    Ridha, A.A.; Mutter, M.M.; Salim, M.D.

    2015-01-01

    The study of natural radioactivity in public universities soil is very important because of containing a large numbers of students and personnel in small areas and for long periodic times, especially the centers and gathering students areas. So it was chosen the most important universities in Baghdad city according with the students density, which is Baghdad and Nahrain University in Al-Jadriyah region in addition to Al-Mustansiriyah University in Palestine street region. Thirteen soil samples collected from these regions to estimate the radiological impact to the dweller, the concentrations of 238 U, 232 Th and 40 K present in the soil samples were analyzed using HPGe as Gamma-spectrometry. The results showed that the average radioactivity of 238 U is 26.262±4.52 Bq/ kg, for 232 Th is equal to 24.860±4.03 Bq/ kg and for 40 K is 293.706±16.62 Bq/ kg. Thus, the values of specific activity of 238 U, 232 Th and 40 K for all soil samples are in acceptable values of the worldwide average. The maximum value for Ra eq is 119.727±10.94 Bq/ kg recorded in sample (Bag2), with an average value of 76.938±8.44 Bq/ kg. All soil samples have Ra eq value below the 247 Bq/ kg (Iraqi permissibility limit). In addition to radium equivalent, the absorbed gamma dose rate (D), outdoor annual effective dose and hazard indices are calculated in this work and show low values compared with permissible limits. (author)

  12. Determination of the concentration of 238U, 234U, 232Th, 228Th, 228Ra, 226Ra and 210Pb in the feces of workers from a mining company of niobium and their families

    International Nuclear Information System (INIS)

    Oliveira, Roges de; Lopes, Ricardo T.; Melo, Dunstana R.; Juliao, Ligia M.Q.C.

    2005-01-01

    The object of this study consists of an open mine from which Niobium ore (pyrochlore) is extracted and a metallurgy company, where Fe-Nb alloys are produced for export. For geological reasons, the main ore is associated to natural radionuclides U and Th, and its decay products. The concentration of 234 U, 238 U, 232 Th, 226 Ra and 228 Ra, 228 Th, including 210 Pb in fecal excretion of 12:0 am, 29 workers and 13 family members were determined. The technique employed for the determination of the elements was the sequential method of radiochemical separation, followed by alpha spectrometry and counting α and β in proportional detector. Statistically significant difference was observed in the concentration of 234 U and 238 U, in feces samples, among the group of mining workers and family members; as well as for 232 Th in the feces of workers of crushing and metallurgy groups when compared with the Family Group. No statistically significant difference was detected at a concentration of 226 Ra, 228 Ra and 210 Pb, in feces of any group of workers of the installation in relation to the family group

  13. 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.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  16. 238U series isotopes and 232Th in carbonates and black shales from the Lesser Himalaya: implications to dissolved uranium abundances in Ganga-Indus source waters

    International Nuclear Information System (INIS)

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

    2003-01-01

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

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

    Science.gov (United States)

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

    2017-07-01

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

  18. 230Th, 232Th and 238U determinations in phosphoric acid fertilizer and process products by ICP-MS

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  19. The fission cross sections of 230Th, 232Th, 233U, 234U, 236U, 238U, 237Np, 239Pu and 242Pu relative 235U at 14.74 MeV neutron energy

    International Nuclear Information System (INIS)

    Meadows, J.W.

    1986-12-01

    The measurement of the fission cross section ratios of nine isotopes relative to 235 U at an average neutron energy of 14.74 MeV is described with particular attention to the determination of corrections and to sources of error. The results are compared to ENDF/B-V and to other measurements of the past decade. The ratio of the neutron induced fission cross section for these isotopes to the fission cross section for 235 U are: 230 Th - 0.290 +- 1.9%; 232 Th - 0.191 +- 1.9%; 233 U - 1.132 +- 0.7%; 234 U - 0.998 +- 1.0%; 236 U - 0.791 +- 1.1%; 238 U - 0.587 +- 1.1%; 237 Np - 1.060 +- 1.4%; 239 Pu - 1.152 +- 1.1%; 242 Pu - 0.967 +- 1.0%. 40 refs., 11 tabs., 9 figs

  20. 235U, 238U, 232Th, 40K and 137Cs activity concentrations in marine sediments along the northern coast of Oman Sea using high-resolution gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Zare, Mohammad Reza; Mostajaboddavati, Mojtaba; Kamali, Mahdi; Abdi, Mohammad Reza; Mortazavi, Mohammad Seddigh

    2012-01-01

    The natural radioactivity levels in sediment samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz canyon to Goatr seaport, as the first time has been determined. The results of measurements will serve as background reference level for Oman Sea coastlines. Sediments from 36 coastal and near shore locations were collected for analysis. Analysis on the collected samples were carried out to determine 235 U, 238 U, 232 Th, 40 K and 137 Cs using two high purity germanium detectors with 38.5% and 55% relative efficiencies. The concentration of 235 U, 238 U, 232 Th, 40 K and 137 Cs in sediment samples ranged between 1.01 and 2.87 Bq/kg, 11.83 and 22.68 Bq/kg, 10.7 and 25.02 Bq/kg, 222.89 and 535.07 Bq/kg and 0.14 and 2.8 Bq/kg, respectively. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose.

  1. 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)

  2. Determination of committed effective doses to skin due to 238U, 232Th and 222Rn from the application of various Moroccan black soap (Saboun Beldi) samples by members of the general public

    International Nuclear Information System (INIS)

    Misdaq, M. A.; Outeqablit, K.

    2010-01-01

    238 U, 232 Th, 222 Rn and 220 Rn concentrations were measured inside various Moroccan black soap samples widely used by the Moroccan population in traditional baths (Hammams) by using both CR-39 and LR-115 type II solid state nuclear track detectors. The measured 238 U, 232 Th, 222 Rn and 220 Rn concentrations, respectively, ranged from (3.7±0.2) to (11.7±0.7) mBq kg -1 , (0.11±0.01) to (0.32±0.02) mBq kg -1 , (3.8±0.2) to (11.6±0.6) Bq kg -1 and (0.10±0.01) to (0.31±0.02) Bq kg -1 for the Moroccan black soap samples studied. The influence of pollution on the concentrations of these radionuclides inside the considered Moroccan black soap was investigated. A new dosimetric model for evaluating annual committed effective doses due to 238 U, 232 Th and 222 Rn to the skin of different age groups of the Moroccan populations from the application of the black soap samples studied was developed. The maximum total committed effective dose to the skin due to 238 U, 232 Th and 222 Rn from the application of unpolluted black soap samples 20 min per week by the Moroccan populations was found to be equal to (0.88±0.05) μSv y -1 cm -2 . (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Reza Abdi, Mohammad [Department of Physics, University of Isfahan, Isfahan 81747-73441 (Iran, Islamic Republic of)], E-mail: r.abdi@phys.ui.ac.ir; Kamali, Mehdi [Central Laboratory, University of Isfahan, Isfahan 81747-73441 (Iran, Islamic Republic of); Vaezifar, Sedigheh [Department of Chemistry, University of Isfahan, Isfahan 81747-73441 (Iran, Islamic Republic of)

    2008-04-15

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  5. 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)

  6. Neutron induced fission cross sections for /sup 232/Th, /sup 235,238/U, /sup 237/Np and /sup 239/Pu from 1 to 400 MeV

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-01-01

    Neutron-induced fission cross section ratios for samples of /sup 232/Th, /sup 235,238/U, /sup 237/Np and /sup 239/Pu have been measured from 1 to 400 MeV. The fission reaction rate was determined for all samples simultaneously using a fast parallel plate ionization chamber at a 20-m flight path. A well characterized annular proton recoil telescope was used to measure the neutron fluence up to 30 MeV. These data provided the shape of the /sup 235/U(n,f) cross section relative to the hydrogen scattering cross section. That shape was then normalized to the very accurately known values were determined using the neutron fluence measured with a second proton recoil telescope. Cross section values for /sup 232/Th, /sup 238/U, /sup 237/Np, and /sup 239/Pu were computed from the ratio data using our values for /sup 235/U(n,f). In addition to providing new results at high neutron energies, these data resolve long standing discrepancies among different data sets. 1 ref., 1 fig.

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

    International Nuclear Information System (INIS)

    Su Qiong; Cheng Jianping; Diao Lijun; Li Guiqun

    2006-01-01

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

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

    International Nuclear Information System (INIS)

    Su Qiong; Cheng Jianping; Diao Lijun; Li Guiqun

    2007-01-01

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

  9. Production of 231Pa and 232U by irradiation of 230Th/232Th mixtures

    International Nuclear Information System (INIS)

    Kluge, E.; Lieser, K.H.

    1981-01-01

    The production of 231 Pa and of 232 U by irradiating a 230 Th/ 232 Th mixture (containing 12 mol per cent 230 Th) in form of ThO 2 at a thermal neutron flux of 6.9 x 10 13 cm -2 s -1 for 4 months was investigated. Pa, U and Th were separated and the chemical yields were determined. 2.6% of the 230 Th were transformed into 231 Pa and 0.13% into 232 U. These values are higher than those calculated for a thermal flux, but lower than those calculated for a flux ratio epithermal to thermal = 0.03. 231 Pa and 232 U were isolated in form of a protactinium solution and of U 3 O 8 with 94.9 and 89.1% chemical yields, respectively. Foreign activities were not detected. Thorium was recuperated and isolated as ThO 2 , with a chemical yield of 93.6%. (orig.)

  10. 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.

  11. 230Th-238U radioactive disequilibria in tholeiites from the FAMOUS zone (Mid-Atlantic Ridge, 36050'N): Th and Sr isotopic geochemistry

    International Nuclear Information System (INIS)

    Condomines, M.; Morand, P.; Allegre, C.J.

    1981-01-01

    We analyzed, U, Th and 230 Th/ 232 Th activity ratios for a few tholeiites from the Mid-Atlantic Ridge FAMOUS zone at 36 0 50'N. The results show a fairly wider scatter for both Th/U and ( 230 Th/ 232 Th) ratios. Seawater contamination appears to be responsible for this scatter and, for the uranium, produces an increase in content yielding a ( 234 U/ 238 U) ratio greater than 1 and, for the Th, an increase of the ( 230 Th/ 232 Th) ratio which is a very sensitive indicator for contamination. Also, the latter often is selective: U, Th and Sr are not affected in the same manner. When discarding all data for contaminated samples, the FAMOUS zone appears to be very homogeneous with a Th/U ratio value of 3.05 and a ( 230 Th/ 232 Th) ratio value of 1.24. Comparison with other active volcanic areas reveals a negative correlation between ( 230 Th/ 232 Th) and 87 Sr/ 86 Sr ratios for present lavas which is indicative of a consistency in Th-U and Rb-Sr fractionation in the source regions of these magmas. The Th isotopic geochemistry can thus provide useful information for the study of present volcanism, information as valuable as that from Sr, Pb or Nd isotopes. (orig.)

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

    International Nuclear Information System (INIS)

    Silva, Carolina Fernanda da

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  14. 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

  15. Speciation analysis of 129I, 137Cs, 232Th, 238U, 239Pu and 240Pu in environmental soil and sediment

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hansen, Violeta; Hou, Xiaolin

    2012-01-01

    The environmental mobility and bioavailability of radionuclides are related to their physicochemical forms, namely species. We here present a speciation analysis of important radionuclides including 129I (also 127I), 137Cs, 232Th, 238U and plutonium isotopes (239Pu and 240Pu) in soil (IAEA-375......) and sediment (NIST-4354) standard reference materials and two fresh sediment samples from Øvre Heimdalsvatnet Lake, Norway. A modified sequential extraction protocol was used for the speciation analysis of these samples to obtain fractionation information of target radionuclides. Analytical results reveal...

  16. Direct Measurement of Initial 230TH/ 232TH Ratios in Central Texas Speleothems for More Accurate Age Determination

    Science.gov (United States)

    Wortham, B. E.; Banner, J. L.; James, E.; Loewy, S. L.

    2013-12-01

    Speleothems, calcite deposits in caves, preserve a record of climate in their growth rate, isotope ratios and trace element concentrations. These variables must be tied to precise ages to produce pre-instrumental records of climate. The 238U-234U- 230Th disequilibrium method of dating can yield precise ages if the amount of 230Th from the decay of radiogenic 238U can be constrained. 230Th in a speleothem calcite growth layer has two potential sources - 1) decay of radioactive 238U since the time of growth of the calcite layer; and 2) initial detrital 230Th, incorporated along with detrital 232Th, into the calcite layer at the time it grew. Although the calcite lattice does not typically incorporate Th, samples can contain impurities with relatively high Th contents. Initial 230Th/232Th is commonly estimated by assuming a source with bulk-Earth U/Th values in a state of secular equilibrium in the 238U-decay chain. The uncertainty in this 230Th/232Th estimate is also assumed, typically at +/-100%. Both assumptions contribute to uncertainty in ages determined for young speleothems. If the amount of initial detrital 230Th can be better quantified for samples or sites, then U-series ages will have smaller uncertainties and more precisely define the time series of climate proxies. This study determined the initial 230Th/232Th of modern calcite to provide more precise dates for central Texas speleothems. Calcite was grown on glass-plate substrates placed under active drips in central Texas caves. The 230Th/232Th of this modern calcite was determined using thermal ionization mass spectrometry. Results show that: 1) initial 230Th/232Th ratios can be accurately determined in these young samples and 2) measuring 230Th/232Th reduces the uncertainties in previously-determined ages on stalagmites from under the same drips. For example, measured initial 230Th/232Th in calcite collected on substrates from different locations in the cave at Westcave Preserve are 15.3 × 0.67 ppm

  17. Quantification of {sup 232}Th, {sup 234}U, {sup 235}U and {sup 238}U in river mollusks by magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS); Cuantificacion de {sup 232}Th, {sup 234}U, {sup 235}U y {sup 238}U en moluscos de rios por espectrometria de masas de sector magnetico con fuente de plasma acoplado inductivamente (ICP-SFMS)

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo R, D. L.; Hernandez M, H.; Romero G, E. T.; Lara A, N. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Alfaro de la T, M. C., E-mail: arevalo0591@hotmail.com [Universidad Autonoma de San Luis Potosi, Dr. Salvador Nava s/n, Zona Universitaria, 78290 San Luis Potosi, SLP (Mexico)

    2016-09-15

    The present work deals with the methodology established for the quantification of {sup 232}Th, {sup 234}U, {sup 238}U and {sup 235}U in the shell of gastropod mollusks collected in the rivers Valles, Coy and Axtla of San Luis Potosi, Mexico, which belong to the Panuco River basin; these rivers have as main source of pollution the discharge of municipal sewage, waste from small industries, agricultural and cattle residues and from natural sources. Conventional methods for measuring radio-nuclides are confronted with certain conditions related to the requirement in measurement, basically in the characterization that is related to the concepts of precision and accuracy. The analysis of the gastropod mollusk shell was performed by the Icp-SFMS technique; the main advantages of this technique lie in the isotope quantification capacity, the high precision and the low limits of detection, in this study are very important because these elements are in concentrations between ppb and ppt. This technique allowed the analysis of the samples having a complex matrix by the presence CaCO{sub 3} minimizing the interferences thanks to the ionization efficiency of the Ar plasma. For the species Pachychilus monachus were found concentrations of {sup 232}Th of 0.16-5.37 μg/g and of total U of 0.101-4.081 μg/g being this species where the highest values of total U were found. For Thiara (melanoids) tuberculata the lowest values were found among the different species ({sup 232}Th 0.61-3.61 μg/g and total U 0.006-0.042 μg/g), for Pachychilus suturalis, values of {sup 232}Th of 0.58-6.4 μg/g and for Pachychilus sp. were found between 0.26-7.62 μg/g and for total U values between 0.28-3.33 μg/g. The method offers several advantages: speed, good precision, low values of quantification limits and high sensitivity in the measurement of radio-nuclides and heavy metals. (Author)

  18. Daily ingestion of 232Th, 238U, 226Ra, 228Ra and 210Pb in vegetables by inhabitants of Rio de Janeiro City

    International Nuclear Information System (INIS)

    Santos, E.E.; Lauria, D.C.; Amaral, E.C.S.; Rochedo, E.R.

    2002-01-01

    The concentrations of the naturally occurring radionuclides 232 Th, 238 U, 210 Pb, 226 Ra and 228 Ra were determined in the vegetables (leafy vegetables, fruit, root, bean and rice) and derived products (sugar, coffee, manioc flour, wheat flour, corn flour and pasta) consumed most by the adult inhabitants of Rio de Janeiro City. A total of 88 samples from 26 different vegetables and derived products were analyzed. The highest contribution to radionuclide intake arises from bean, wheat flour, manioc flour, carrot, rice, tomato and potato consumption. The estimated daily intakes due to the consumption of vegetables and derived products are 1.9 mBq of 232 Th (0.47 μg), 2.0 mBq of 238 U (0.17 μg), 19 mBq of 226 Ra, 26 mBq of 210 Pb and 47 mBq of 228 Ra. The estimated annual effective dose due to the ingestion of vegetables and their derived products with the long-lived natural radionuclides is 14.5 μSv. Taking into account literature data for water and milk from Rio de Janeiro the dose value increases to 29 μSv, with vegetables and derived products responsible for 50% of the dose and water for 48%. 210 Pb (62%) and 228 Ra (24%) were found to be the main sources for internal irradiation

  19. 230Th-238U disequilibrium systematics in oceanic tholeiites from 210N on the East Pacific Rise

    International Nuclear Information System (INIS)

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

    1983-01-01

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

  20. Mass-yield distributions of fission products from 20, 32, and 45 MeV proton-induced fission of 232Th

    Science.gov (United States)

    Naik, H.; Goswami, A.; Kim, G. N.; Kim, K.; Suryanarayana, S. V.

    2013-10-01

    The yields of various fission products in the 19.6, 32.2, and 44.8 MeV proton-induced fission of 232Th have been determined by recoil catcher and an off-line γ-ray spectrometric technique using the BARC-TIFR Pelletron in India and MC-50 cyclotron in Korea. The mass-yield distributions were obtained from the fission product yield using the charge distribution corrections. The peak-to-valley (P/V) ratio of the present work and that of literature data for 232Th(p,f) and 238U(p,f) were obtained from the mass yield distribution. The present and the existing literature data for 232Th(p,f), 232Th(n,f), and 232Th( γ,f) at various energies were compared with those for 238U(p,f), 238U(n,f), and 238U( γ,f) to examine the probable nuclear structure effect. The role of Th-anomaly on the peak-to-valley ratio in proton-, neutron-, and photon-induced fission of 232Th was discussed with the similar data in 238U. On the other hand, the fine structure in the mass yield distributions of the fissioning systems at various excitation energies has been explained from the point of standard I and II asymmetric mode of fission besides the probable role of even-odd effect, A/ Z ratio, and fissility parameter.

  1. Assessment of radiological impact in mineral industrial plants caused by deposition of wastes with U238 and/or Th232 associated

    International Nuclear Information System (INIS)

    Ladeira, Paula C.; Alves, Rex Nazare; Ruperti Junior, Nerbe J.

    2011-01-01

    The industrial-mining facilities constantly produce, in Brazil and in abroad, wastes from its production, many times containing uranium and/or thorium associated. Due to the large quantities generated, these wastes are usually deposited at the site of the facility, close to the place where they were produced. Since the chains of radioactive U 238 and Th 232 with alpha-emitting radionuclides have long half-life, waste deposits associated with these elements may cause radiological impact on the man and on the environment, even in the long term. Mathematical models are often used to represent the biosphere and the transport of radionuclides near to the surface. Thus, it was decided, through the software M athematica , to present a methodology based on the solution of Bateman equations for the calculation of radiological impact on individuals from the public exposed to contamination. The radiological impact appraisal was carried out considering a scenario of intrusion into landfills containing U 238 and / or Th 232 in post-operational phase of an industrial-mining installation. The critical group examined was represented by farmers who used water from an artesian well for daily consumption and which feed themselves on vegetables locally grown in clay soil. As a result, there was the exposure in pathways evaluated, a minor contribution of dose for ingestion of contaminated water. The conclusion of this work, show us that calculated doses were within the accepted international limits for the intrusion scenario. Parameters associated with mathematical models defining the choice of project to build a landfill for the purpose of deposition, whereas rates of doses can be estimated in each of the scenarios proposed. (author)

  2. Rare-gas yields in 238U and 232Th fission by 14MeV neutrons, measured by an emanating method

    International Nuclear Information System (INIS)

    Feu Alvim, C.A.; Bocquet, J.P.; Brissot, R.; Crancon, J.; Moussa, A.

    1977-01-01

    A direct method, using emanation of rare gases by uranyle stearate and thorium stearate, has been applied to the measurement of cumulative fractional yields of certain isotopes of krypton and xenon, in the fissions of 238 U and 232 Th by 14MeV-neutrons. The independent yields of the same isotopes were measured previously by means of isotopic on-line separation. From these results, the widths of the mass and charge distributions, the relative chain yields, the fractional cumulative yields of certain bromine and iodine isotopes, the values of Zsub(p) the most probable charge, in the isobaric chains 87-93 and 137-142, and the elemental yields of krypton and xenon were calculated [fr

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-12-31

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

  4. 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.

  5. A four phases model to simulate the dispersion of 226Ra, 238U and 232Th in an estuary affected by phosphate rock processing

    International Nuclear Information System (INIS)

    Perianez, R.; Abril, J.M.; Garcia-Leon, M.

    1997-01-01

    A numerical model to simulate the dispersion of non conservative radionuclides in tidal waters has been developed. The model includes four phases: water, suspended matter and two grain size sediment fractions. Ionic exchanges between water and the solid phases have been formulated in terms of kinetic transfer coefficients instead of distribution coefficients, because the model was developed for nonequilibrium conditions. The model simultaneously solves the shallow water hydrodynamic equations, the suspended matter dispersion equation and the four equations which give the time evolution of specific activity in each phase. The model has been applied to the Odiel river (southwest Spain), where a phosphate complex releases its wastes. It gives good results in predicting concentrations of 226 Ra, 238 U and 232 Th in water, suspended matter, distribution coefficients and Th/U mass rations. (author)

  6. Mass-yield distributions of fission products from 20, 32, and 45 MeV proton-induced fission of {sup 232}Th

    Energy Technology Data Exchange (ETDEWEB)

    Naik, H.; Goswami, A. [Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai (India); Kim, G.N.; Kim, K. [Kyungpook National University, Department of Physics, Daegu (Korea, Republic of); Suryanarayana, S.V. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India)

    2013-10-15

    The yields of various fission products in the 19.6, 32.2, and 44.8 MeV proton-induced fission of {sup 232}Th have been determined by recoil catcher and an off-line {gamma}-ray spectrometric technique using the BARC-TIFR Pelletron in India and MC-50 cyclotron in Korea. The mass-yield distributions were obtained from the fission product yield using the charge distribution corrections. The peak-to-valley (P/V) ratio of the present work and that of literature data for {sup 232}Th(p,f) and {sup 238}U(p,f) were obtained from the mass yield distribution. The present and the existing literature data for {sup 232}Th(p,f), {sup 232}Th(n,f), and {sup 232}Th({gamma},f) at various energies were compared with those for {sup 238}U(p,f), {sup 238}U(n,f), and {sup 238}U({gamma},f) to examine the probable nuclear structure effect. The role of Th-anomaly on the peak-to-valley ratio in proton-, neutron-, and photon-induced fission of {sup 232}Th was discussed with the similar data in {sup 238}U. On the other hand, the fine structure in the mass yield distributions of the fissioning systems at various excitation energies has been explained from the point of standard I and II asymmetric mode of fission besides the probable role of even-odd effect, A/Z ratio, and fissility parameter. (orig.)

  7. The fission cross sections of /sup 230/Th, /sup 232/Th, /sup 233/U, /sup 234/U, /sup 236/U, /sup 238/U, /sup 237/Np, /sup 239/Pu and /sup 242/Pu relative /sup 235/U at 14. 74 MeV neutron energy

    Energy Technology Data Exchange (ETDEWEB)

    Meadows, J.W.

    1986-12-01

    The measurement of the fission cross section ratios of nine isotopes relative to /sup 235/U at an average neutron energy of 14.74 MeV is described with particular attention to the determination of corrections and to sources of error. The results are compared to ENDF/B-V and to other measurements of the past decade. The ratio of the neutron induced fission cross section for these isotopes to the fission cross section for /sup 235/U are: /sup 230/Th - 0.290 +- 1.9%; /sup 232/Th - 0.191 +- 1.9%; /sup 233/U - 1.132 +- 0.7%; /sup 234/U - 0.998 +- 1.0%; /sup 236/U - 0.791 +- 1.1%; /sup 238/U - 0.587 +- 1.1%; /sup 237/Np - 1.060 +- 1.4%; /sup 239/Pu - 1.152 +- 1.1%; /sup 242/Pu - 0.967 +- 1.0%. 40 refs., 11 tabs., 9 figs.

  8. Rapid screening of natually occurring radioactive nuclides({sup 2}'3{sup 8}U, {sup 232}Th) in raw materials and by-products samples using XRF

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Young; Lim, Chung Sup [Radiation Biotechnology and Applied Radioiostope Science, University of Science and Technology, Daejeon (Korea, Republic of); Lim, Jong Myoung; Ji, Young Yong; Chung, Kun Ho; Lee, Wan No; Kang, Mun Ja [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Jang, Byung Uck [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2016-12-15

    As new legislation has come into force implementing radiation safety management for the use of naturally occurring radioactive materials (NORM), it is necessary to establish a rapid and accurate measurement technique. Measurement of {sup 238}U and {sup 232}Th using conventional methods encounter the most significant difficulties for pretreatment (e.g., purification, speciation, and dilution/enrichment) or require time-consuming processes. Therefore, in this study, the applicability of ED-XRF as a non-destructive and rapid screening method was validated for raw materials and by-product samples. A series of experiments was conducted to test the applicability for rapid screening of XRF measurement to determine activity of {sup 238}U and {sup 23{sup 2}}Th based on certified reference materials (e.g., soil, rock, phosphorus rock, bauxite, zircon, and coal ash) and NORM samples commercially used in Korea. Statistical methods were used to compare the analytical results of ED-XRF to those of certified values of certified reference materials (CRM) and inductively coupled plasma mass spectrometry (ICP-MS). Results of the XRF measurement for {sup 238}U and {sup 232}Th showed under 20% relative error and standard deviation. The results of the U-test were statistically significant except for the case of U in coal fly ash samples. In addition, analytical results of {sup 238}U and {sup 232}Th in the raw material and by-product samples using XRF and the analytical results of those using ICP-MS (R{sup 2}≥0.95) were consistent with each other. Thus, the analytical results rapidly derived using ED-XRF were fairly reliable. Based on the validation results, it can be concluded that the ED-XRF analysis may be applied to rapid screening of radioactivities ({sup 238}U and {sup 232}Th) in NORM samples.

  9. Quantification of "2"3"2Th, "2"3"4U, "2"3"5U and "2"3"8U in river mollusks by magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS)

    International Nuclear Information System (INIS)

    Arevalo R, D. L.; Hernandez M, H.; Romero G, E. T.; Lara A, N.; Alfaro de la T, M. C.

    2016-09-01

    The present work deals with the methodology established for the quantification of "2"3"2Th, "2"3"4U, "2"3"8U and "2"3"5U in the shell of gastropod mollusks collected in the rivers Valles, Coy and Axtla of San Luis Potosi, Mexico, which belong to the Panuco River basin; these rivers have as main source of pollution the discharge of municipal sewage, waste from small industries, agricultural and cattle residues and from natural sources. Conventional methods for measuring radio-nuclides are confronted with certain conditions related to the requirement in measurement, basically in the characterization that is related to the concepts of precision and accuracy. The analysis of the gastropod mollusk shell was performed by the Icp-SFMS technique; the main advantages of this technique lie in the isotope quantification capacity, the high precision and the low limits of detection, in this study are very important because these elements are in concentrations between ppb and ppt. This technique allowed the analysis of the samples having a complex matrix by the presence CaCO_3 minimizing the interferences thanks to the ionization efficiency of the Ar plasma. For the species Pachychilus monachus were found concentrations of "2"3"2Th of 0.16-5.37 μg/g and of total U of 0.101-4.081 μg/g being this species where the highest values of total U were found. For Thiara (melanoids) tuberculata the lowest values were found among the different species ("2"3"2Th 0.61-3.61 μg/g and total U 0.006-0.042 μg/g), for Pachychilus suturalis, values of "2"3"2Th of 0.58-6.4 μg/g and for Pachychilus sp. were found between 0.26-7.62 μg/g and for total U values between 0.28-3.33 μg/g. The method offers several advantages: speed, good precision, low values of quantification limits and high sensitivity in the measurement of radio-nuclides and heavy metals. (Author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-15

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

  11. Assessment of radiological impact in mineral industrial plants caused by deposition of wastes with U{sup 238} and/or Th{sup 232} associated

    Energy Technology Data Exchange (ETDEWEB)

    Ladeira, Paula C.; Alves, Rex Nazare, E-mail: rexnazare@ime.eb.b [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Ruperti Junior, Nerbe J., E-mail: nruperti@cnen.gov.b [Comissao Nacional de Energia Nuclear (DIREJ/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Div. de Rejeitos Radioativos

    2011-07-01

    The industrial-mining facilities constantly produce, in Brazil and in abroad, wastes from its production, many times containing uranium and/or thorium associated. Due to the large quantities generated, these wastes are usually deposited at the site of the facility, close to the place where they were produced. Since the chains of radioactive U{sup 238} and Th{sup 232} with alpha-emitting radionuclides have long half-life, waste deposits associated with these elements may cause radiological impact on the man and on the environment, even in the long term. Mathematical models are often used to represent the biosphere and the transport of radionuclides near to the surface. Thus, it was decided, through the software {sup M}athematica{sup ,} to present a methodology based on the solution of Bateman equations for the calculation of radiological impact on individuals from the public exposed to contamination. The radiological impact appraisal was carried out considering a scenario of intrusion into landfills containing U{sup 238} and / or Th{sup 232} in post-operational phase of an industrial-mining installation. The critical group examined was represented by farmers who used water from an artesian well for daily consumption and which feed themselves on vegetables locally grown in clay soil. As a result, there was the exposure in pathways evaluated, a minor contribution of dose for ingestion of contaminated water. The conclusion of this work, show us that calculated doses were within the accepted international limits for the intrusion scenario. Parameters associated with mathematical models defining the choice of project to build a landfill for the purpose of deposition, whereas rates of doses can be estimated in each of the scenarios proposed. (author)

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

    International Nuclear Information System (INIS)

    Godoy, Jose Marcus de Oliveira

    1979-10-01

    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)

  13. 238U, 234U and 230Th in uranium miners' lungs

    International Nuclear Information System (INIS)

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

    1981-01-01

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

  14. Mobility of radionuclides and trace elements in soil from legacy NORM and undisturbed naturally 232Th-rich sites.

    Science.gov (United States)

    Mrdakovic Popic, Jelena; Meland, Sondre; Salbu, Brit; Skipperud, Lindis

    2014-05-01

    Investigation of radionuclides (232Th and 238U) and trace elements (Cr, As and Pb) in soil from two legacy NORM (former mining sites) and one undisturbed naturally 232Th-rich site was conducted as a part of the ongoing environmental impact assessment in the Fen Complex area (Norway). The major objectives were to determine the radionuclide and trace element distribution and mobility in soils as well as to analyze possible differences between legacy NORM and surrounding undisturbed naturally 232Th-rich soils. Inhomogeneous soil distribution of radionuclides and trace elements was observed for each of the investigated sites. The concentration of 232Th was high (up to 1685 mg kg(-1), i.e., ∼7000 Bq kg(-1)) and exceeded the screening value for the radioactive waste material in Norway (1 Bq g(-1)). Based on the sequential extraction results, the majority of 232Th and trace elements were rather inert, irreversibly bound to soil. Uranium was found to be potentially more mobile, as it was associated with pH-sensitive soil phases, redox-sensitive amorphous soil phases and soil organic compounds. Comparison of the sequential extraction datasets from the three investigated sites revealed increased mobility of all analyzed elements at the legacy NORM sites in comparison with the undisturbed 232Th-rich site. Similarly, the distribution coefficients Kd (232Th) and Kd (238U) suggested elevated dissolution, mobility and transportation at the legacy NORM sites, especially at the decommissioned Nb-mining site (346 and 100 L kg(-1) for 232Th and 238U, respectively), while the higher sorption of radionuclides was demonstrated at the undisturbed 232Th-rich site (10,672 and 506 L kg(-1) for 232Th and 238U, respectively). In general, although the concentration ranges of radionuclides and trace elements were similarly wide both at the legacy NORM and at the undisturbed 232Th-rich sites, the results of soil sequential extractions together with Kd values supported the expected differences

  15. Application of activation technique for mass and nuclear charge distributions studies of 3 Mev and 14 Mev neutrons induced 238-U(n,f) and 232-Th(n,f)

    International Nuclear Information System (INIS)

    Embarch, K.

    1988-01-01

    Fission product cumulative and independent yields were determined for 238-U(n,f) and 232-Th(n,f) reactions with essentially monoenergetic neutrons of 3 and 14 Mev. Fission product activities were measured by Ge(Li)γ-ray spectrometry of irradiated 238-U and 232-Th foils. These experiments allowed us to measure a great number of cumulative yields and to obtain the fission product mass distributions corresponding to the studied reactions mentioned above. The mass distributions were completely interpreted by nucleon shell effects and proton even-odd effects. The independent yield measurements are sometimes not possible using the activation technique because of the fission fragment decay data. The values which can not be measured were determined using the measured mass yields and a prediction systematic of fractional independent yield. The results allowed us to obtain the nuclear charge distributions and to estimate proton even-odd effect corresponding values. This effect decreases when the excitation energy of the fissioning nucleus increases, this shows the importance of this parameter in the viscosity study of the nuclear matter. In conclusion, the shell effects observed in the mass distributions show that the static aspect of the fission mechanism plays a great role during the fission process, and observed proton even-odd effects act for a weak nuclear viscosity. 54 refs., 27 figs., 25 tabs

  16. 238U, 234U and 230Th in uranium miners' lungs

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  17. Determination of 230Th/232Th and correct methods by High Resolution Inductively Coupled Plasma Mass Spectrometry

    International Nuclear Information System (INIS)

    Xie Shengkai; Guo Dongfa; Tan Jing; Zhang Yanhui; Huang Qiuhong; Gao Aiguo

    2013-01-01

    It is very important for the rapid and reliable determination of 230 Th/ 232 Th in the thorium-230 dating. A method of measuring 230 Th/ 232 Th in natural samples by high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) was developed on the base of our former work. The precise and accurate of natural 230 Th in geology samples is challenging, as the peak tailing to the high intensity of neighboring peak at 232 Th and the mass discrimination of the instrument. The peak tailing of 238 U to 236 U was used to decrease the peak tailing effect of 232 Th to 230 Th. The mass discrimination factor K between ture and measured isotope ratio was calculated after measuring different 230 Th/ 232 Th ratio solutions. Lab used standard samples was digested in mixed acids of HN0 3 -HF-HCI-HCl0 4 , and separated by the Bio-rad AG 1 × 8 Cl - resin. The measurement method of blank-standard-blank-sample procession was used to determinate the 230 Th/ 232 Th. The measured result of 230 Th/ 232 Th was at (7.29 ± 0.34) × 10 -6 , which agreed with the reference value of (7.33 ± 0.17) × 10 -6 . (authors)

  18. 232Th and 238U neutron emission cross section calculations and analysis of experimental data

    International Nuclear Information System (INIS)

    Tel, E.

    2004-01-01

    In this study, pre-equilibrium neutron-emission spectra produced by (n,xn) reactions on nuclei 2 32Th and 2 38U have been calculated. Angle-integrated cross sections in neutron induced reactions on targets 2 32Th and 2 38U have been calculated at the bombarding energies up to 18 MeV. We have investigated multiple pre-equilibrium matrix element constant from internal transition for 2 32Th (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 232 T h and 2 38U, 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

  19. Tracing changes in mantle and crustal influences in individual cone-building stages at Mt. Shasta using U-Th and Sr isotopes

    Science.gov (United States)

    Wende, Allison M.; Johnson, Clark M.; Beard, Brian L.

    2015-10-01

    230Th-excess is rare in most arc lavas, but common in the Cascades, yet the origin of such excesses remains unclear. At Mt. Shasta, age-corrected (230Th/232Th) and (238U/232Th) activity ratios range from 1.108 to 1.290 and from 0.987 to 1.309 (27.3% 230Th-excess to 6.1% 238U-excess), respectively. Although small degrees of zircon crystallization (ancestral cone (Sand Flat) was followed by four cone-building stages, three of which lie in the age range of U-series geochronology. Lavas within individual eruptive stages have relatively constant (230Th/232Th)0 ratios that are interpreted to reflect specific mixtures of mantle (m) and lower crustal (lc) melts that are characteristic of a specific stage (Mm:lc). High (230Th/232Th)0 ratios identify higher proportions of lower crust in the Misery Hill stage (Mm:lc = ∼ 85 : 15), whereas low (230Th/232Th)0 ratios reflect the more mantle-like composition of the Shastina lavas (Mm:lc = ∼ 95 : 5); in the case of Shastina lavas, very low 87Sr/86Sr ratios, down to 0.7029, support a substantial mantle contribution. Changes in (230Th/232Th)0 ratios correlate with eruptive volume, where the most voluminous stage (Misery Hill) is inferred to have the largest proportion of crustal melt and highest (230Th/232Th)0 ratios. Variable (230Th/238U)0 ratios within, and between, eruptive groups likely reflect a combination of residence time in the lower crust and differential assimilation of bulk, non-garnet-bearing crust that had (230Th/238U) = 1. The volume-(230Th/232Th)0 relations are accompanied by correlations with 87Sr/86Sr ratios, where the most radiogenic Sr is associated with the largest eruptive volumes, indicating that the largest magmatic episodes produced the largest amount of lower crustal interaction. The new U-Th and Sr isotope measurements of this study, along with U-series data for other Cascade centers suggest that interaction with the lower crust exerts greater control on Cascade magma chemistry than previously

  20. Measurements of prompt fission neutron spectra and double-differential neutron inelastic-scattering cross sections for 238U and 232Th

    International Nuclear Information System (INIS)

    Baba, Mamoru; Itoh, Nobuo; Maeda, Kazuto; Hirakawa, Naohiro; Wakabayashi, Hidetaka.

    1989-10-01

    This report presents the summary of experimental studies of prompt fission neutron spectra and double-differential neutron inelastic-scattering cross sections of 238 U and 232 Th. The experiments were performed at Tohoku University Fast Neutron Laboratory employing a time-of-flight technique and Dynamitron accelerator as the pulsed neutron generator. From the experiments, we obtained the following data for both nuclei; 1. prompt fission neutron spectrum for 2 MeV neutrons, 2. double-differential neutron inelastic-scattering cross sections for 1.2, 2.0, 4.2, 6.1 and 14.1 MeV incident neutrons. Both in experiments and data processing, cares were taken to obtain reliable data by avoiding systematic uncertainty. The experimental data were compared with those by other experiments, evaluations and model calculations. Through the data comparison, some fundamental problems were found in the experiments by previous authors and the evaluations. The present data will provide useful data base for refinement of the evaluated data and theoretical models. (author)

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

    International Nuclear Information System (INIS)

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

    1980-01-01

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

  2. Neutron induced fission cross section ratios for 232Th, 235,238U, 237Np and 239Pu from 1 to 400 MeV

    International Nuclear Information System (INIS)

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

    1988-01-01

    Time-of-flight measurements of neutron induced fission cross section ratios for 232 Th, 235,238 U, 237 Np, and 239 Pu, were performed using the WNR high intensity spallation neutron source located at Los Alamos National Laboratory. A multiple-plate gas ionization chamber located at a 20-m flight path was used to simultaneously measure the fission rate for all samples over the energy range from 1 to 400 MeV. Because the measurements were made with nearly identical neutron fluxes, we were able to cancel many systematic uncertainties present in previous measurements. This allows us to resolve discrepancies among different data sets. In addition, these are the first neutron-induced fission cross section values for most of the nuclei at energies above 30 MeV. (author)

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

    Directory of Open Access Journals (Sweden)

    I. P. Stamat

    2008-01-01

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

  4. Relics of continental lithosphere in the atlantic by data of (Th/U)th, (Th/U)pb, and K/Ti systematics

    International Nuclear Information System (INIS)

    Titayeva, N.A.; Mironov, Y.

    1996-01-01

    The problem of mantle heterogeneity of the Atlantic Ocean has been investigated. Th/U ratio is a sensitive geochemical tracer. This ratio can be calculated from 232Th/230Th or from 208Pb/206Pb since 230Th and 206Pb are decay product of 238U and 208Pb is a product of 232Th decay. The former way to get Th/U ratio is valid for quaternary volcanic rocks because of the relatively short 230Th half life (80000 years), the latter way gives an integral quantity characterizing the pre-oceanic history beginning from the onset of earth formation and ending about 150 million years ago. Clear distinctions between ''depleted oceanic'' and ''enriched continental'' reservoirs have been drawn from comparative analysis of rocks. (A.C.)

  5. 230Th/U-dating of a late Holocene low uranium speleothem from Cuba

    International Nuclear Information System (INIS)

    Fensterer, Claudia; Mangini, Augusta; Scholz, Denis; Hoffmann, Derik; Pajon, Jesus M

    2010-01-01

    We present 22 U-series ages for a stalagmite from north-western Cuba based on multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and thermal ionisation mass spectrometry (TIMS). Our results reveal that the stalagmite continuously grew within the last ∼1400a. Low uranium content of the sample and thus, extremely low 230 Th concentrations limit the precision and accuracy of 230 Th/U-dating by TIMS. Samples measured by MC-ICPMS show a high variability of 232 Th content along the growth axis with some sections significantly affected by initial 230 Th from a detrital phase. An a-priori bulk earth ratio for ( 238 U/ 232 Th) cannot be used to accurately account for this initial 230 Th. Using an age model based on the 230 Th/U ages determined on samples with low or negligible 232 Th concentration, we find that the ( 238 U/ 232 Th) activity ratio of the detrital phase is an order of magnitude larger than the bulk earth value, indicating the importance of an accurately determined correction factor.

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  7. Influence of form factors and multistep effects on the 232Th(d,t) 231Th and 230Th(d,p) 231Th reactions

    International Nuclear Information System (INIS)

    Wilcke, W.; Felix, W.; Elze, Th.W.; Huizenga, J.R.; Thompson, R.C.; Dreisler, R.M.

    1977-01-01

    Tables of spectroscopic information are given for the nuclei 233 , 235 , 237 Pa, and 229 , 231 Ac studied in the reactions 234 , 236 , 238 U, and 230 , 232 Th(t,α), including spin, parity, differential cross sections, and spectra. These quantities are discussed and plotted

  8. Measurement of the cross sections for the 238U(n,2n) and 232Th(n,2n) reactions in the 13.5 - 14.8 MeV energy range

    International Nuclear Information System (INIS)

    Raics, P.; Nagy, S.; Daroczy, S.; Kornilov, N.V.

    1990-10-01

    (n,2n) reaction cross sections have been determined for 238 U and 232 Th by using the activation method. Neutrons were produced in D-T reaction by bombarding a TiT target with analyzed deuteron beam from a Cockcroft-Walton accelerator. Neutron energy was varied by changing the emission angle to the deuteron beam. The activities of the 237 U and 231 Th residual nuclei were measured by a Ge(Li) and a HP Ge gamma-spectrometer, respectively. Several standard reactions were used for the determination of the neutron flux density. An overall precision of 3.5 - 4.5% was estimated and a 1.4 - 3.5% reproducibility was achieved. Comparison of the recent results to literature data and a brief analysis of the monitor reactions are given. (author). 48 refs, 3 figs, 7 tabs

  9. Neutron induced fission cross section ratios for 232Th, /sup 235,238/U, 237Np, and 239Pu from 1 to 400 MeV

    International Nuclear Information System (INIS)

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

    1988-01-01

    Time-of-flight measurements of neutron induced fission cross section ratios for 232 Th, /sup 235,238/U, 237 Np, and 239 Pu, were performed using the WNR high intensity spallation neutron source located at Los Alamos National Laboratory. A multiple-plate gas ionization chamber located at a 20-m flight path was used to simultaneously measure the fission rate for all samples over the energy range from 1 to 400 MeV. Because the measurements were made with nearly identical neutron fluxes, we were able to cancel many systematic uncertainties present in previous measurements. This allows us to resolve discrepancies among different data sets. In addition, these are the first neutron-induced fission cross section values for most of the nuclei at energies above 30 MeV. 8 refs., 3 figs

  10. {sup 230}Th/U-dating of a late Holocene low uranium speleothem from Cuba

    Energy Technology Data Exchange (ETDEWEB)

    Fensterer, Claudia; Mangini, Augusta [Forschungsstelle Radiometrie, Heidelberg Academy of Sciences, Im Neuenheimer Feld 229, 69120 Heidelberg (Germany); Scholz, Denis; Hoffmann, Derik [School of Geographical Sciences, University of Bristol, University Road, BS8 1SS, Bristol (United Kingdom); Pajon, Jesus M, E-mail: Claudia.Fensterer@iup.uni-heidelberg.d [Department of Archaeology, Cuban Institute of Anthropology, Amargura No. 203, e/n Habana y Aguiar, Ciudad de La Habana, CP: 10 100 (Cuba)

    2010-03-15

    We present 22 U-series ages for a stalagmite from north-western Cuba based on multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and thermal ionisation mass spectrometry (TIMS). Our results reveal that the stalagmite continuously grew within the last {approx}1400a. Low uranium content of the sample and thus, extremely low {sup 230}Th concentrations limit the precision and accuracy of {sup 230}Th/U-dating by TIMS. Samples measured by MC-ICPMS show a high variability of {sup 232}Th content along the growth axis with some sections significantly affected by initial {sup 230}Th from a detrital phase. An a-priori bulk earth ratio for ({sup 238}U/{sup 232}Th) cannot be used to accurately account for this initial {sup 230}Th. Using an age model based on the {sup 230}Th/U ages determined on samples with low or negligible {sup 232}Th concentration, we find that the ({sup 238}U/{sup 232}Th) activity ratio of the detrital phase is an order of magnitude larger than the bulk earth value, indicating the importance of an accurately determined correction factor.

  11. Determination of radioactivity levels in phosphate-containing fertilizers, copper and gold ores by direct gamma-ray spectroscopy. U-238, Th-232, K-40, and Ra-226 in fertilizers and ores

    International Nuclear Information System (INIS)

    Constantinescu, B.; Constantin, F.; Dusoiu, N.; Pascovoici, G.

    1996-01-01

    Two particular sources from the natural radiation background which may be encountered in Romanian industry are here presented: the phosphate containing fertilizers and the gold and copper ores, respectively. U-238, Th-232, K-40, and Ra-226 activity levels for several imported phosphorites, superphosphates and also for concentrated Cu and Au indigenous ores are reported. A simple and efficient radioactivity determination procedure based on a large volume NaI(Tl) detector, coupled to a Romanian design portable multichannel analyzer is described. Potential radiological impacts for the specialized workers are also discussed. (author) 1 fig., 4 tabs. 6 refs

  12. Assessment of airborne 238U and 232Th exposure and dust load impact on people living in the vicinity of a cement factory in Ghana

    International Nuclear Information System (INIS)

    Addo, Moses Ankamah; Gbadago, J.K.; Ameyaw, Felix; Darko, E.O.; Gordon, Chris; Davor, Peter; Faanu, A.; Kpeglo, David

    2014-01-01

    Globally, the cement industry has been identified as one which causes significant particle pollution. In Ghana, environmental research in the neighborhood of the cement industry especially on human health is scanty. In the present work, attempts were made to evaluate the concentration of airborne dust at various distances and directions around the Diamond Cement Factory in the Volta Region of Ghana. The samples of dust were collected on filter papers and later analyzed for the concentration (mg/kg) of 232 Th and 23 '8U using neutron activation analysis. The principal objective of the study was to generate data intended at assessing the annual effective dose due to 232 Th and 238 U inhalation for both adult and children population living in the vicinity of cement factory. The data generated were supposed to assist in remediation decision making, if required. The study recorded a few incidences of higher total dust load concentrations as compared to the permissible limit of 150 μg/m 3 specified by the Ghana Environmental Protection Agency. The calculated mean effective doses were 28.2 ± 1.06 μSv/year and 25.9 ± 0.91 μSv/year for both adult and child, respectively. From the radiological point of view, the study concluded that the people living in the vicinity of the cement factory are not at risk to significant radiological hazards. However, the study indicated the need to have a complete evaluation of the impact of the factory on the environment assessment programs which should include both chemical and radiological toxicity. (author)

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  14. Mass distributions in monoenergetic-neutron-induced fission of 232Th

    International Nuclear Information System (INIS)

    Glendenin, L.E.; Gindler, J.E.; Ahmad, I.; Henderson, D.J.; Meadows, J.W.

    1980-01-01

    Fission product yields for 38 masses were determined for the fission of 232 Th with essentially monoenergetic neutrons of 2.0, 3.0, 4.0, 5.9, 6.4, 6.9, 7.6, and 8.0 MeV. Fission product activities were measured by Ge(Li) γ-ray spectrometry of irradiated 232 Th foils and by chemical separation of the fission product elements followed by β counting. The mass yield data for 232 Th(n,f ) show a sensitive increase of fission yields in the near-symmetric mass region (valley) with increasing incident neutron energy E/sub n/ and a pronounced dip in yield at the onset of second-chance fission just above the neutron binding energy (at approx. 6 MeV) where the excitation energy is lowered by competition with neutron evaporation prior to fission. The effect of second-chance fission is also seen in the yields of asymmetric peak products. A distinct third peak is observed at symmetry in the valley of the mass distribution, and enhanced yields are observed in the asymmetric peaks at masses associated with even Z (proton pairing effect). The fission yeilds of 232 Th(n,f ) are compared with those of 238 U(n,f ) and 232 Th

  15. 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)

    Santos, Rosana Nunes dos

    2001-01-01

    This work describes the implementation of experimental procedures for alpha spectrometry measurement of 238 U, 234 U and 230 Th activities in silicates. The best experimental conditions were defined using 233 U, 232 U and 229 Th 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 238 U and 232 Th series disequilibrium conditions were investigated by alpha spectrometry, together with neutron activation analysis and natural gamma-ray spectrometry. 234 U/ 238 U, 238 U/ 232 Th and 230 Th/ 232 Th activity ratios and the 234 Th, 214 Pb, 214 Bi, 235 U, 228 Ac, 212 Pb, 212 Bi and 208 Tl 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 232 Th series is in secular radioactive equilibrium in all analysed samples. In the case of the 238 U 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 230 Th and 238 U are not in

  16. Physics concept on the constellation type fissile fuels and its application to the prospective Th-232U Reactor

    International Nuclear Information System (INIS)

    Zhang, Jiahua

    1994-01-01

    In contrast with the conventional nuclear reactor which usually fuelled with on single fissile nuclide, a constellation type fissile fuels reactor consists of a parent nuclide such as 232 Th or 238 U and its whole family of neutron generated daughter nuclides. All of them are regarded as fissile fuels but of quite different fission ability. The concentration of each daughter nuclide is determined by its saturate concentration ratio with the parent nuclide. In such fuel system, the whole fuel consumed by neutron reaction almost completely results in fission products. In this article, some properties of such fuel system, determination of the saturate concentration of each daughter nuclide and applicability to Th- 233 U fueled reactor will be discussed. 3 refs., 1 tab., 2 figs

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

    International Nuclear Information System (INIS)

    Reinitz, I.; Turekian, K.K.

    1989-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-10-15

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

  19. Differential geochemical behaviour of natural isotopes of U and Th in an aquifer in humid tropical terrain

    International Nuclear Information System (INIS)

    Bonotto, D.M.

    1989-01-01

    Uranium and thorium isotopic analyses were performed on spoil samples from the saturated zone of a borehole drilled in the main ore body of a high grade thorium/rare earth ore, and on groundwaters from a borehole drilled in the zone. The deposit is located at Morro do Ferro, a hill near the centre of the Pocos de Caldas Plateau (MG), where an aquifer system developed in the weathered mantle due to in situ intense alteration. For extraction of uranium and thorium a long chemical process was applied to the samples; activities of Th-228 and Th-232 isotopes (4n series) and also of U-238, U-234 and Th-230 isotopes (4n+2 series) were determined by the alpha spectrometry method. U-234/U-238 activity ratios in groundwaters were between 1 and 2 but Th-228/Th-232 activity ratios showed marked isotopic fractionation between these nuclides. The mechanism of mobilization of uranium by complexation with humic substances is considered. U-234/U-238, Th-228/Th-232 and Th-230/U-234 activity ratios in soil samples allowed consider action of other possible mechanisms related to the mobilization of uranium, such as, ion-exchange reaction and adsorption by Fe and Mn oxides. (author) [pt

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

    International Nuclear Information System (INIS)

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

    1992-01-01

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

  1. Neutron induced fission cross section ratios for /sup 232/Th, /sup 235,238/U, /sup 237/Np, and /sup 239/Pu from 1 to 400 MeV

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-01-01

    Time-of-flight measurements of neutron induced fission cross section ratios for /sup 232/Th, /sup 235,238/U, /sup 237/Np, and /sup 239/Pu, were performed using the WNR high intensity spallation neutron source located at Los Alamos National Laboratory. A multiple-plate gas ionization chamber located at a 20-m flight path was used to simultaneously measure the fission rate for all samples over the energy range from 1 to 400 MeV. Because the measurements were made with nearly identical neutron fluxes, we were able to cancel many systematic uncertainties present in previous measurements. This allows us to resolve discrepancies among different data sets. In addition, these are the first neutron-induced fission cross section values for most of the nuclei at energies above 30 MeV. 8 refs., 3 figs.

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

    International Nuclear Information System (INIS)

    McKenzie, D.

    1985-01-01

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

  3. 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...

  4. 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).

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

    International Nuclear Information System (INIS)

    Abdullah, Anisa; Hamzah, Zaini; Wood, Ab. Khalik; Saat, Ahmad

    2016-01-01

    Distribution of radionuclides from anthropogenic activities has been widely studied in marine coastal area. Due to rapid population growth and socio-economic development in Manjung area such as coal fired power plant, iron foundries, port development, waste discharged from factories and agriculture runoff may contribute to increase in pollution rate. The radioactive materials from anthropogenic activities could deteriorate the quality of the marine ecosystem and thus lead to possible radiological health risk to the population. Radionuclides ( 232 Th, 238 U and 40 K) content in surface and profile sediment from Manjung coastal area was determined in this study. Radionuclides in sediment from seven locations were collected using sediment core sampling and measurements were carried out using Energy Dispersive X-ray Fluorescence (EDXRF) spectroscopy. The results show that the concentration of radionuclides in surface sediment and distribution trend of depth vertical profile sediment generally varies depending on locations. Enrichment factors (EF), geo-accumulation index (I geo ) and pollution index (PI) were applied to determine level of pollution of this study area. The radiological risks related to human exposure were evaluated based on external hazard index (H ex )

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

    Science.gov (United States)

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

    2017-08-01

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

  7. Neutron-induced reactions on U and Th - A new approach via AMS

    International Nuclear Information System (INIS)

    Wallner, A.; Capote, R.; Christl, M.; Fifield, L.K.; Srncik, M.; Tims, S.; Hotchkis, M.; Krasa, A.; Lachner, J.; Lippold, J.; Plompen, A.; Semkova, V.; Steier, P.; Winkler, S.

    2014-01-01

    Recent studies exhibit discrepancies at keV and MeV energies between major nuclear data libraries for 238 U(n,γ), 232 Th(n,γ) and also for (n,xn) reactions. We have extended our initial (n,γ) measurements on 235,238 U to higher neutron energies and to additional reaction channels. Neutron-induced reactions on 232 Th and 238 U were measured by a combination of the activation technique and atom counting of the reaction products using accelerator mass spectrometry (AMS). Natural thorium and uranium samples were activated with quasi-monoenergetic neutrons at IRMM. Neutron capture data were produced for neutron energies between 0.5 and 5 MeV. Fast neutron-induced reactions were studied in the energy range from 17 to 22 MeV. Preliminary data indicate a fair agreement with data libraries; however at the lower band of existing data. This approach represents a complementary method to on-line particle detection techniques and also to conventional decay counting. (authors)

  8. U-Th-Ra disequilibria at the Masaya (Nicaragua); Desequilibres U-Th-Ra au Masaya (Nicaragua)

    Energy Technology Data Exchange (ETDEWEB)

    Sigmarsson, O; Condomines, M [Centre de Recherches Volcanologiques, CNRS URA-10, 63 - Clermont Ferrand (France)

    1997-12-31

    {sup 238}U-{sup 230}Th-{sup 226}Ra radioactive disequilibria were measured in several basalt samples of the post-caldera flows of the Masaya volcano (Nicaragua). {sup 230}Th/{sup 232}Th ratios are from the highest known in the world (about 2.53) with {sup 230}Th/{sup 238}U ratios close to 1. These exceptionally high isotopic thorium ratios from the Masaya and other neighboring volcanoes (Conception, Cerro Negro, Momotombo) are followed by very high {sup 10}Be/{sup 9}Be ratios (60 10{sup -11} for the 1722 flow). These geochemical characteristics with {delta}{sup 18}O of typical mantle origin (5.55) suggest an influence of the subducted sediments fluids in the magma source. The age of the metasomatism ranges from 10 to 0.3 Ma. Initial {sup 226}Ra/{sup 230}Th ratios measured in four historical flows vary from 1.3 to 1.4 and are anti-correlated with the Th content. These variations are probably linked to the fractionated crystallisation of plagioclase minerals. The initial {sup 226}Ra/Ba ratio remains constant and suggests the existence of a huge stationary magmatic reservoir. This hypothesis is also confirmed by the disproportion between the SO{sub 2} quantity emitted by the volcano and by the degassing of lavas on the ground. The {sup 226}Ra excess observed in the Masaya lavas can be the result of a second stage of metasomatism which occurred less than 8000 years B.P. during partial fusion. Abstract only. (J.S.).

  9. U-Th-Ra disequilibria at the Masaya (Nicaragua); Desequilibres U-Th-Ra au Masaya (Nicaragua)

    Energy Technology Data Exchange (ETDEWEB)

    Sigmarsson, O.; Condomines, M. [Centre de Recherches Volcanologiques, CNRS URA-10, 63 - Clermont Ferrand (France)

    1996-12-31

    {sup 238}U-{sup 230}Th-{sup 226}Ra radioactive disequilibria were measured in several basalt samples of the post-caldera flows of the Masaya volcano (Nicaragua). {sup 230}Th/{sup 232}Th ratios are from the highest known in the world (about 2.53) with {sup 230}Th/{sup 238}U ratios close to 1. These exceptionally high isotopic thorium ratios from the Masaya and other neighboring volcanoes (Conception, Cerro Negro, Momotombo) are followed by very high {sup 10}Be/{sup 9}Be ratios (60 10{sup -11} for the 1722 flow). These geochemical characteristics with {delta}{sup 18}O of typical mantle origin (5.55) suggest an influence of the subducted sediments fluids in the magma source. The age of the metasomatism ranges from 10 to 0.3 Ma. Initial {sup 226}Ra/{sup 230}Th ratios measured in four historical flows vary from 1.3 to 1.4 and are anti-correlated with the Th content. These variations are probably linked to the fractionated crystallisation of plagioclase minerals. The initial {sup 226}Ra/Ba ratio remains constant and suggests the existence of a huge stationary magmatic reservoir. This hypothesis is also confirmed by the disproportion between the SO{sub 2} quantity emitted by the volcano and by the degassing of lavas on the ground. The {sup 226}Ra excess observed in the Masaya lavas can be the result of a second stage of metasomatism which occurred less than 8000 years B.P. during partial fusion. Abstract only. (J.S.).

  10. 234Th/238U disequilibrium in near-shore sediment: particle reworking and diagenetic time scales

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  11. Evaluation of cross sections of Th-232 and U-233

    International Nuclear Information System (INIS)

    Dias, A.M.

    1978-01-01

    The cross sections in multigroups of Th-232 and U-233 are evaluated by comparison of theoretical results and experimental data obtained through experiments on the fast reactors IBR-I, EBR-II, BR-I and AETR. The deviation between calculated values and experimental results is about 10%. They are therefore satisfatory for neutronic calculations [pt

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

    International Nuclear Information System (INIS)

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

    1988-04-01

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

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

    International Nuclear Information System (INIS)

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

    1982-07-01

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

  14. HI-resolution gamma spectrometry measurements of U-238, TH-232, K-40 and CS-137 concentrations in soil samples from Capao Island at CTEx

    International Nuclear Information System (INIS)

    Oliveira, Luciano S.R.; Oliveira, Celio J.V.; Vilela, Paulo R.T.; Vital, Helio C.

    2013-01-01

    Absolute soil concentrations of U-238, Th-232, K-40 and Cs-137 samples collected from Capao Island have been measured by using Hi-Resolution Gamma HPGe Spectrometry. The area of interest encompasses an embankment in a mangrove swamp in Guaratiba, Rio de Janeiro, where nuclear, chemical and biological defense laboratories of the Brazilian Army Technology Center (CTEx) are located. In order to ensure that no significant environmental impact has resulted from neutron physics experiments performed in a graphite subcritical assembly in addition to the operation of two cesium-driven irradiating facilities, routine monitoring of those isotopes have been regularly performed. A total of eight 250 ml samples of mangrove and embankment soils were extracted from four sites of known coordinates within an area of 300 x 300 m 2 and remained stored for a minimum thirty-day period to allow equilibrium to be reached. Collection and preparation of samples were made according to previously established procedures. High purity germanium detectors were used to obtain high-resolution gamma spectra and counting times were required to exceed 30 hours in order to yield sufficient statistical accuracy. Energy and efficiency calibration curves of the counting system were determined by using the GENIE 2000 software for analysis of the gamma spectrum generated by nine standard sources with a total of 11 peak energies ranging from 0.05 to 1.3 MeV. The results, corrected for background, have been expressed as absolute specific activities. All experiments have been made in the Laboratory for Identification of Radiological Agents (LIAR) at CTEx. No trace of cesium-137 has been found and the measured levels of uranium-238, in the order of 10 Bq/kg, are close to the global mean. However, some data have been found to slightly exceed the expected normal range for thorium-232 (60% of samples) and potassium-40 (20% of samples). Since there is no handling of those isotopes in the site or others that could

  15. HI-resolution gamma spectrometry measurements of U-238, TH-232, K-40 and CS-137 concentrations in soil samples from Capao Island at CTEx

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luciano S.R.; Oliveira, Celio J.V.; Vilela, Paulo R.T.; Vital, Helio C., E-mail: vital@ctex.eb.br [Centro Tecnologico do Exercito (DDQBN/CTEX), Rio de Janeiro, RJ (Brazil). Div. de Defesa Quimica, Biologica e Nuclear. Secao de Defesa Nuclear

    2013-07-01

    Absolute soil concentrations of U-238, Th-232, K-40 and Cs-137 samples collected from Capao Island have been measured by using Hi-Resolution Gamma HPGe Spectrometry. The area of interest encompasses an embankment in a mangrove swamp in Guaratiba, Rio de Janeiro, where nuclear, chemical and biological defense laboratories of the Brazilian Army Technology Center (CTEx) are located. In order to ensure that no significant environmental impact has resulted from neutron physics experiments performed in a graphite subcritical assembly in addition to the operation of two cesium-driven irradiating facilities, routine monitoring of those isotopes have been regularly performed. A total of eight 250 ml samples of mangrove and embankment soils were extracted from four sites of known coordinates within an area of 300 x 300 m{sup 2} and remained stored for a minimum thirty-day period to allow equilibrium to be reached. Collection and preparation of samples were made according to previously established procedures. High purity germanium detectors were used to obtain high-resolution gamma spectra and counting times were required to exceed 30 hours in order to yield sufficient statistical accuracy. Energy and efficiency calibration curves of the counting system were determined by using the GENIE 2000 software for analysis of the gamma spectrum generated by nine standard sources with a total of 11 peak energies ranging from 0.05 to 1.3 MeV. The results, corrected for background, have been expressed as absolute specific activities. All experiments have been made in the Laboratory for Identification of Radiological Agents (LIAR) at CTEx. No trace of cesium-137 has been found and the measured levels of uranium-238, in the order of 10 Bq/kg, are close to the global mean. However, some data have been found to slightly exceed the expected normal range for thorium-232 (60% of samples) and potassium-40 (20% of samples). Since there is no handling of those isotopes in the site or others that

  16. Analysis of photofission reactions of 235U, 238U, 232Th, 209Bi, natPb, 197Au, natPt, natW, 181Ta, and 27Al by photons of 69 MeV

    International Nuclear Information System (INIS)

    Paiva, Eduardo de

    1997-04-01

    Fission reactions induced in 235 U, 238 U, 232 Th, 209 Bi nat Pb, 197 Au, nat Pt, nat W, 181 Ta. and 27 Al nuclei by monochromatic photons of 69 MeV produced at the LADON facility of the Frascati National Laboratories (INFN-LNF, Frascati, Italy) have been analyzed on the basis of a simplified two-step model. In the first step of the reaction the incoming photon is considered to be absorbed by a neutron-proton pair ('quasi-deuteron') leading to excitation of the nucleus, followed, in the second step, by a mechanism of particle evaporation-fission competition for the excited residual nucleus. Estimates of nuclear fissility at 69 MeV show to be critically dependent on the parameter r (ratio of the level-density parameter at the fission saddle point to the level-density parameter of the residual nucleus after neutron evaporation), which can be determined in a semiempirical way from induced fission reaction data for various nuclei obtained at 60 - 80 MeV of excitation energy. Fissilities calculated by means of the simplified photofission reactions model are then compared with experimental data available in the literature. (author)

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

    International Nuclear Information System (INIS)

    Stoop, P.; Lembrechts, J.

    1993-04-01

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

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

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

    International Nuclear Information System (INIS)

    Kurihara, Yuichi; Takahashi, Masaomi; Sato, Jun

    2008-01-01

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

  1. Void reactivity feedback analysis for U-based and Th-based LWR incineration cycles

    Energy Technology Data Exchange (ETDEWEB)

    Lindley, B.A.; Parks, G.T. [Cambridge University Engineering Department, Trumpington Street, Cambridge, CB2 1PZ (United Kingdom); Franceschini, F. [Westinghouse Electric Company LLC, Cranberry Township, PA (United States)

    2013-07-01

    In reduced-moderation LWRs, an external supply of transuranic (TRU) can be incinerated by mixing it with a fertile isotope ({sup 238}U or {sup 232}Th) and recycling all the actinides after each cycle. Performance is limited by coolant reactivity feedback - the moderator density coefficient (MDC) must be kept negative. The MDC is worse when more TRU is loaded, but TRU feed is also needed to maintain criticality. To assess the performance of this fuel cycle in different neutron spectra, three LWRs are considered: 'reference' PWRs and reduced-moderation PWRs and BWRs. The MDC of the equilibrium cycle is analysed by reactivity decomposition with perturbed coolant density by isotope and neutron energy. The results show that using {sup 232}Th as a fertile isotope yields superior performance to {sup 238}U. This is due essentially to the high resonance η of U bred from Th (U3), which increases the fissility of the U3-TRU isotope vector in the Th-fueled system relative to the U-fueled system, and also improves the MDC in a sufficiently hard spectrum. Spatial separation of TRU and U3 in the Th-fueled system renders further improvement by hardening the neutron spectrum in the TRU and softening it in the U3. This improves the TRU η and increases the negative MDC contribution from reduced thermal fission in U3. (authors)

  2. Distribution of uranium-238 in environmental samples from a residential area impacted by mining and milling activities

    International Nuclear Information System (INIS)

    McConnell, M.A.; Ramanujam, V.M.S.; Alcock, N.W.; Gabehart, G.J.; Au, W.W.

    1998-01-01

    The northern region of Karnes County, Texas, USA, has been the site of extensive mining/milling of uranium for over 30 years. A previous study in their laboratory indicates that residents living near these facilities have increased chromosomal aberrations and a reduced DNA repair capacity. In this study, the long-lived radionuclides uranium-238 ( 238 U) and thorium-232 ( 232 Th) were measured in order to evaluate the extent of contamination from mining/milling facilities. 232 Th was quantified simultaneously and served as a reference. Soil samples were collected from the yards of previously studied households and adjacent areas near former mining and mining/milling sites at the surface and 30 cm subsurface. Additionally, samples from drinking water wells were collected from selected households. Sites located over 14 km from the study area with no known history of mining/milling served as the control. In the control area, 238 U concentrations in soil were consistent between surface (0.13--0.26 mg/kg) and subsurface samples. Near mining/milling sites, 238 U in surface soil was found to be consistently and statistically higher than corresponding subsurface samples. Near mining-only areas, 238 U in surface soil, however, was not significantly increased over subsurface soil. As expected, 238 U was much higher overall in the mining/milling and mining-only areas compared to the control sites. No trends were detected in the distribution of 232 Th. The concentration of 238 U was up to six times higher in a drinking water well near a former mining/milling operation, indicating possible leaching into the groundwater, while 232 Th concentrations were low and uniform. Furthermore, lead isotope ratio analysis indicates contamination from the interstate shipping of ore by rail to and from a mining/milling facility. These data indicate contamination of the environment by the mining/milling activities in a residential area

  3. Collective and single-particle excitations in the heavy deformable nuclei 234U, 233U, 231Th, 230Pa and 232Pa

    International Nuclear Information System (INIS)

    Kotthaus, Tanja

    2010-01-01

    In this thesis five heavy deformed isotopes from the mass region A≥230, namely 234 U, 233 U, 231 Th, 230 Pa and 232 Pa, were investigated by means of deuteron-induced neutron transfer reactions. The even-even isotope 234 U has been studied with the 4π-γ-spectrometer MINIBALL at the Cologne Tandem accelerator. Excited nuclei in the isotope 234 U were produced using the reaction 235 U(d,t) at a beam energy of 11 MeV. The target thickness was 3.5 mg/cm 2 . The analysis of the γγ-coincidence data yielded a reinterpretation of the level scheme in 12 cases. Considering its decay characteristics, the 4 + state at an excitation energy of 1886.7 keV is a potential candidate for a two-phonon vibrational state. The isotopes 233 U, 231 Th, 230 Pa and 232 Pa were investigated at the Munich Q3D spectrometer. For each isotope an angular distribution with angles between 5 and 45 were measured. In all four cases the energy of the polarized deuteron beam (vector polarization of 80%) was 22 MeV. As targets 234 U (160 μg/cm 2 ), 230 Th (140 μg/cm 2 ) and 231 Pa (140 μg/cm 2 ) were used. The experimental angular distributions were compared to results of DWBA calculations. For the odd isotope 233 U spin and parity for 33 states are assigned and in the other odd isotope 231 Th 22 assignments are made. The excitation spectra of the two odd-odd isotopes 230 Pa and 232 Pa were investigated for the first time. For the isotope 230 Pa 63 states below an excitation energy of 1.5 MeV are identified. Based on the new experimental data the Nilsson configuration of the ground state is either 1/2[530] p -5/2[633] n or 1/2[530] p +3/2[631] n . In addition 12 rotational bands are proposed and from this six values for the GM splitting energy are deduced as well as two new values for the Newby shift. In the other odd-odd isotope 232 Pa 40 states below an excitation energy of 850 keV are observed and suggestions for the groundstate band and its GM partner are made. From this one GM splitting

  4. 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)

    Bonotto, D.M.

    1991-01-01

    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)

  5. (232)Th(d,4n)(230)Pa cross-section measurements at ARRONAX facility for the production of (230)U.

    Science.gov (United States)

    Duchemin, C; Guertin, A; Haddad, F; Michel, N; Métivier, V

    2014-05-01

    (226)Th (T1/2=31 min) is a promising therapeutic radionuclide since results, published in 2009, showed that it induces leukemia cells death and activates apoptosis pathways with higher efficiencies than (213)Bi. (226)Th can be obtained via the (230)U α decay. This study focuses on the (230)U production using the (232)Th(d,4n)(230)Pa(β-)(230)U reaction. Experimental cross sections for deuteron-induced reactions on (232)Th were measured from 30 down to 19 MeV using the stacked-foil technique with beams provided by the ARRONAX cyclotron. After irradiation, all foils (targets as well as monitors) were measured using a high-purity germanium detector. Our new (230)Pa cross-section values, as well as those of (232)Pa and (233)Pa contaminants created during the irradiation, were compared with previous measurements and with results given by the TALYS code. Experimentally, same trends were observed with slight differences in orders of magnitude mainly due to the nuclear data change. Improvements are ongoing about the TALYS code to better reproduce the data for deuteron-induced reactions on (232)Th. Using our cross-section data points from the (232)Th(d,4n)(230)Pa reaction, we have calculated the thick-target yield of (230)U, in Bq/μA·h. This value allows now to a full comparison between the different production routes, showing that the proton routes must be preferred. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Contribution of some food categories on intakes of U, Th and other nuclides

    International Nuclear Information System (INIS)

    Shiraishi, Kunio

    1999-01-01

    The assessment of radiation dose in human from radioactive 232 Th, 238 U, 137 Cs, and 90 Sr are important because those nuclides are the largest contributors to committed internal doses. A market basket study was conducted to clarify the food pathways of the nuclides in Japanese subjects. Foodstuffs of 336 were purchased from markets in the vicinity of Mito-City during 1994-1995. Statistical consumption data were used for collection of the food samples. Thorium-232, 238 U, and stable isotope ( 133 Cs) in eighteen food groups were determined by inductively coupled mass spectrometry (ICP-MS). Radioisotopes ( 137 Cs) was analyzed by γ-spectrometry. Stable strontium ( 88 Sr) was also analyzed by inductively coupled atomic emission spectrometry (ICP-AES). Big contributors to the nuclide intakes in Japanese were as follows: 232 Th fishes and shellfishes (44%) and green vegetables (11%); 238 U seaweeds (50%) and fishes and shellfishes (26%); 88 Sr seaweeds (53%) and fishes and shellfishes (14%); 137 Cs mushrooms (17%), fishes and shell fishes (15%), milk products (11%), meats (9%), and potatoes (7%). The food categories of oil and fats, eggs and cooked meals were minor contributors in those nuclides. Dietary intake studies by using eighteen or more food categories should be effective procedure to resolve critical food and critical pathway for Japanese. Furthermore, critical pathways of radionuclides could be estimated by the analyses of stable isotopes. (author)

  7. Determination of natural radionuclides from 238U and 232Th series, trace and major elements in sediment cores from baixada Santista and evaluation of impacted areas

    International Nuclear Information System (INIS)

    Damatto, Sandra Regina

    2010-01-01

    Baixada Santista is the region of higher population of the coast of Sao Paulo State, where it is located the largest port in Latin America, in the city of Santos, and the most important industrial complex of Latin America, in the city of Cubatao. This region has received in recent years a considerable load of industrial and domestic effluents in its water bodies, as a direct result of the industrial and port activities and the large population growth in recent decades, and is considered nowadays highly impacted. In the present study sediment cores were collected in the estuary of Santos-Cubatao, in the estuary of Sao Vicente, in the channel of Bertioga and Santos Bay, in order to determine the concentration of trace and major elements and natural radionuclides from the 238 U and 232 Th series. The techniques used were neutron activation analysis, X-ray fluorescence and gamma spectrometry, respectively. The obtained values for the elements Cr, Sb, Ta and Zn in some cores, are higher than data from literature, and can indicate a possible anthropic contribution. Comparing the obtained values of Cr and Zn elements determined in the sediment cores with the values of TEL and PEL index for sediment quality, it was verified that the studied region presents Cr levels higher than TEL in Santos-Cubatao estuary and Bertioga channel and Zn element presented values higher than TEL for some core slices of Santos-Cubatao estuary, for one core of Sao Vicente estuary, one core in Bertioga channel and Santos Bay. For the other elements, the values obtained in this study can be considered as reference values for the region. Although the element As presented higher values than the TEL in all the studied environments, the concentrations obtained are of the same order of magnitude as literature data and, therefore, can be considered also as reference values for the region. No enrichment was found for the major elements in all the ecosystems studied, with the exception for the element P

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

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

  9. 238U-230Th dating of chevkinite in high-silica rhyolites from La Primavera and Yellowstone calderas

    Science.gov (United States)

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

    2014-01-01

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

  10. The status of 232Th and 233U for CENDL-3.0

    International Nuclear Information System (INIS)

    Liu Ping

    2003-01-01

    The new version CENDL-3.0 of China: Evaluated nuclear data library has been updated, and contains about 200 nuclides. Among them, the data of following nuclides have been newly evaluated or reevaluated: fissile nuclides 15, structure materials 18, light nuclides 3, fission products 116. The 232 Th and 233 U are newly evaluated

  11. Radiological impact due to natural radionuclides (U and Th-isotopes) in soils from Salamanca, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Mandujano G, C. D.; Sosa, M. [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Loma del Bosque 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Mantero, J.; Manjon, G.; Garcia T, R. [Universidad de Sevilla, Grupo en Fisica Nuclear Aplicada, Av. Reina Mercedes No. 2, 41012 Sevilla (Spain); Costilla, R., E-mail: cmandujano@fisica.ugto.mx [Universidad de Guanajuato, Division de Ciencias de la Vida, Departamento de Ciencias Ambientales, Ex-Hacienda El Copal Km 9 Irapuato-Silao, 36500 Irapuato, Guanajuato (Mexico)

    2015-10-15

    Full text: Activity concentrations of U ({sup 238}U, {sup 234}U) and Th ({sup 232}Th, {sup 230}Th) radionuclides in samples of superficial urban soils surrounding an industrial complex in Salamanca, Mexico have been determined. Levels of naturally occurring radionuclides (Norm) in the environment may be affected due to the presence of different industrial activities in this zone, representing a potential radiological risk for the population which should be evaluated. Alpha-particle Spectrometry with Pips detectors has been used for the radiometric characterization. A well established radiochemical procedure was used for the isolation of the radionuclides of interest. Alkali fusion for sample digestion, liquid-liquid extraction with Tbp (tri-butyl-phosphate) for U and Th isolation and electrodeposition in stainless steel dishes for measurement conditioning has been used. The results cover the ranges of 10-42, 12-60, 12-52 and 11-51 Bq·kg{sup -1} for {sup 238}U, {sup 234}U, {sup 230}Th, and {sup 232}Th respectively, being not observed any clear anthropogenic increments in relation with the values normally found in unaffected soils. Although there is disequilibrium between U isotopes and {sup 230}Th in some soil samples, it can be attributed to natural processes. The radiological impact of the industrial activities in the surrounding soils can be then evaluated as very low. Hence, from the Radiological Protection point of view, the soils studied do not represent a radiological risk for the health of the population. (Author)

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

    International Nuclear Information System (INIS)

    Adam, J.; Chitra Bhatia; Katovskij, K.

    2011-01-01

    Spallation neutrons produced in a collision of 2.33 GeV deuteron beam with the large lead target are moderated by the thick graphite block surrounding the target and used to activate the radioactive samples of nat U and Th put at the 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. Ratio of the experimental reaction rates, R(n, 2n)/R(n, f) for the 232 Th and nat U are estimated in order to understand the role of reactions of (n, xn) type in Accelerator Driven Subcritical Systems. For the Th-sample, the ratio is ∼ 54(10)% in case of hole 'a' and ∼ 95(57)% in case of hole 'b' compared to 1.73(20)% for the hole 'a' and 0.710(9)% for the hole 'b' in case of the nat U sample. Also the ratio of fission rates in uranium to thorium, nat U(n, f)/ 232 Th(n, f), is ∼ 11.2(17) in case of hole 'a' and 26.8(85) in hole 'b'. Similarly, ratio 238 U(n, 2n)/ 232 Th(n, 2n) is 0.36(4) for the hole 'a' and 0.20(10) for the hole 'b' showing that 232 Th is more prone to the (n, xn) reaction than 238 U. 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 LA150 library of cross sections. The experimental and calculated rates of all the three reactions are in good agreement. The transmutation power of the set-up is estimated using the rates of (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

  13. Sequential determination of natural ({sup 232}Th, {sup 238}U) and anthropogenic ({sup 137}Cs, {sup 90}Sr, {sup 241}Am, {sup 239+240}Pu) radionuclides in environmental matrix

    Energy Technology Data Exchange (ETDEWEB)

    Michel, H.; Levent, D.; Barci, V.; Barci-Funel, G.; Hurel, C. [Laboratoire de Radiochimie, Sciences Analytiques et Environnement (LRSAE), Universite de Nice Sophia-Antipolis 06108 Nice Cedex (France)

    2008-07-01

    A new sequential method for the determination of both natural (U, Th) and anthropogenic (Sr, Cs, Pu, Am) radionuclides has been developed for application to soil and sediment samples. The procedure was optimised using a reference sediment (IAEA-368) and reference soils (IAEA-375 and IAEA-326). Reference materials were first digested using acids (leaching), 'total' acids on hot plate, and acids in microwave in order to compare the different digestion technique. Then, the separation and purification were made by anion exchange resin and selective extraction chromatography: Transuranic (TRU) and Strontium (SR) resins. Natural and anthropogenic alpha radionuclides were separated by Uranium and Tetravalent Actinide (UTEVA) resin, considering different acid elution medium. Finally, alpha and gamma semiconductor spectrometer and liquid scintillation spectrometer were used to measure radionuclide activities. The results obtained for strontium-90, cesium-137, thorium-232, uranium- 238, plutonium-239+240 and americium-241 isotopes by the proposed method for the reference materials provided excellent agreement with the recommended values and good chemical recoveries. (authors)

  14. Reply to Comment on "Zircon U-Th-Pb dating using LA-ICP-MS: Simultaneous U-Pb and U-Th dating on the 0.1 Ma Toya Tephra, Japan"

    Science.gov (United States)

    Ito, Hisatoshi

    2015-04-01

    Guillong et al. (2015) mentioned that corrections for abundance sensitivity for 232Th and molecular zirconium sesquioxide ions (Zr2O3+) are critical for reliable determination of 230Th abundances in zircon for LA-ICP-MS analyses. There is no denying that more rigorous treatments are necessary to obtain more reliable ages than those in Ito (2014). However, as shown in Fig. 2 in Guillong et al. (2015), the uncorrected (230Th)/(238U) for reference zircons except for Mud Tank are only 5-20% higher than unity. Since U abundance of Toya Tephra zircons that have U-Pb ages Ito (2014) obtained U-Th ages of the Toya Tephra by comparison with Fish Canyon Tuff (FCT) data. Because both the FCT and the Toya Tephra have similar trends of overestimation of 230Th, the effect of overestimation of 230Th to cause overestimation of U-Th age should be cancelled out or negligible. Therefore the pivotal conclusion in Ito (2014) that simultaneous U-Pb and U-Th dating using LA-ICP-MS is possible and useful for Quaternary zircons holds true.

  15. Discriminating assimilants and decoupling deep- vs. shallow-level crystal records at Mount Adams using 238U-230Th disequilibria and Os isotopes

    Science.gov (United States)

    Jicha, B.R.; Johnson, C.M.; Hildreth, Wes; Beard, B.L.; Hart, G.L.; Shirey, S.B.; Singer, B.S.

    2009-01-01

    A suite of 23 basaltic to dacitic lavas erupted over the last 350??kyr from the Mount Adams volcanic field has been analyzed for U-Th isotope compositions to evaluate the roles of mantle versus crustal components during magma genesis. All of the lavas have (230Th/238U) > 1 and span a large range in (230Th/232Th) ratios, and most basalts have higher (230Th/232Th) ratios than andesites and dacites. Several of the lavas contain antecrysts (crystals of pre-existing material), yet internal U-Th mineral isochrons from six of seven lavas are indistinguishable from their eruption ages. This indicates a relatively brief period of time between crystal growth and eruption for most of the phenocrysts (olivine, clinopyroxene, plagioclase, magnetite) prior to eruption. One isochron gave a crystallization age that is ~ 20-25??ka older than its corresponding eruptive age, and is interpreted to reflect mixing of older and juvenile crystals or a protracted period of magma storage in the crust. Much of the eruptive volume since 350??ka consists of lavas that have small to moderate 230Th excesses (2-16%), which are likely inherited from melting of a garnet-bearing intraplate ("OIB-like") mantle source. Following melt generation and subsequent migration through the upper mantle, most Mt. Adams magmas interacted with young, mafic lower crust, as indicated by 187Os/188Os ratios that are substantially more radiogenic than the mantle or those expected via mixing of subducted material and the mantle wedge. Moreover, Os-Th isotope variations suggest that unusually large 230Th excesses (25-48%) and high 187Os/188Os ratios in some peripheral lavas reflect assimilation of small degree partial melts of pre-Quaternary basement that had residual garnet or Al-rich clinopyroxene. Despite the isotopic evidence for lower crustal assimilation, these processes are not generally recorded in the erupted phenocrysts, indicating that the crystal record of the deep-level 'cryptic' processes has been

  16. Nuclear reactor for breeding 233U

    International Nuclear Information System (INIS)

    Bohanan, C.S.; Jones, D.H.; Raab, H.F. Jr.; Radkowsky, A.

    1976-01-01

    A light-water-cooled nuclear reactor capable of breeding 233 U for use in a light-water breeder reactor includes physically separated regions containing 235 U fissile material and 238 U fertile material and 232 Th fertile material and 239 Pu fissile material, if available. Preferably the 235 U fissile material and 238 U fertile material are contained in longitudinally movable seed regions and the 239 Pu fissile material and 232 Th fertile material are contained in blanket regions surrounding the seed regions. 1 claim, 5 figures

  17. Development of Indian cross section data files for Th-232 and U-233 and integral validation studies

    International Nuclear Information System (INIS)

    Ganesan, S.

    1988-01-01

    This paper presents an overview of the tasks performed towards the development of Indian cross section data files for Th-232 and U-233. Discrepancies in various neutron induced reaction cross sections in various available evaluated data files have been obtained by processing the basic data into multigroup form and intercomparison of the latter. Interesting results of integral validation studies for capture, fission and (n,2n) cross sections for Th-232 by analyses of selected integral measurements are presented. In the resonance range, energy regions where significant differences in the calculated self-shielding factors for Th-232 occur have been identified by a comparison of self-shielded multigroup cross sections derived from two recent evaluated data files, viz., ENDF/B-V (Rev.2) and JENDL-2, for several dilutions and temperatures. For U-233, the three different basic data files ENDF/B-IV, JENDL-2 and ENDL-84 were intercompared. Interesting observations on the predictional capability of these files for the criticality of the spherical metal U-233 system are given. The current status of Indian data file is presented. (author) 62 ref

  18. Disequilibria in the disintegration series of U and Th and chemical parameters in thermal spring waters from the Tatun volcanic area (Taiwan)

    International Nuclear Information System (INIS)

    Lin Chunchih; Chu Tiehchi; Huang Yufen

    2003-01-01

    The activity concentrations of 238 U, 234 U, 230 Th, 226 Ra, 232 Th, and 228 Th in thermal spring waters in the Tatun volcanic area were determined. Parameters including acidity, Cl - and SO 4 2- concentrations in spring waters at the sampling sites have been investigated to allow interpretation of the migration of the radionuclides, and to elucidate the influence of these parameters on the variations of radionuclide contents. Radioactive disequilibria were found in uranium and thorium series in thermal spring waters. The contents of uranium and thorium decreased with increasing pH. The ratios of 230 Th/ 234 U, 226 Ra/ 230 Th and 228 Th/ 232 Th show significant disequilibria. The 226 Ra/ 230 Th ratio (0.60-34.8) decreased with the Cl - or SO 4 2- concentration. All 228 Th/ 232 Th ratios (1.01-9.49) deviated from unity due to the co-precipitation of 228 Ra with barium and lead sulfate. (orig.)

  19. Assessment of the concentrations of U and Th in PM2.5 from Mexico City and their potential human health risk

    International Nuclear Information System (INIS)

    Mendez-Garcia, Carmen Grisel; Solis-Rosales, Corina; Rafael Chavez-Lomeli, Efrain

    2017-01-01

    This is one of the first studies in small particulate matter (PM 2.5 ) by inductively coupled plasma sector field mass spectrometry to measure the activity concentrations of isotopic uranium ( 234 , 235 and 238 U) and thorium ( 232 Th) in these fine particulates, to know their origin and their impact on human health in Mexico City. A different isotopic composition from the natural uranium composition was found. The 235 U/ 238 U atom ratio values are considered as low enrichment uranium, around 2% of 235 U enrichment. Both 235 U/ 238 U and 234 U/ 238 U ratios suggested anthropological rather natural source is impacting the composition of uranium in PM 2.5 . (author)

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  1. Measurement and Analysis of Specific Activities of 238U, 232Th,226Ra, 40K and 137Cs in Soil Samples from Phatthalung Province (Thailand) using Gamma Ray Spectrometry

    International Nuclear Information System (INIS)

    Daoh, Murnee; Kessaratikoon, Prasong; Udomsomporn, Suchin

    2011-06-01

    Full text: Specific activity of natural (238 U , 232 T h, 226 R a and 40 K ) and anthropogenic radionuclide (137 C s) in 109 soil samples collected from 11 districts in Phathalung province have been measured and analyzed. Experimental results were obtained by using a high purity germanium (HPGe) detector and gamma spectrometry analysis system at Nuclear and Material Physics laboratory in Department of Physics Faculty of Science Thaksin University Songkhla Campus. Gamma ray radioactive standard sources 60 C o, 137 C s and 133 B a were used to calibrate the measurement system. The KCl and two reference materials (RGU-1 and RGTh-1) obtained from the International Atomic Energy Agency were also used to analyze and compute the 40 K , 238 U (or 226 R a) and 232 T h specific activity in all soil samples. The IAEA/SL-2 was also used to evaluate the specific activity of 137 C s in all soil samples. The measuring time of each sample was 10,800 seconds. It was found that specific activity ranged from 148.17 to 11276.78 Bq/kg for 40 K , 58.29 to 518.45 Bq/kg for 226 R a, 8.40 to 236.19 Bq/kg for 232 T h and 0.00 tp 12.39 Bq/kg for 137 C s with mean values of 3573.35 ± 203.89 Bq/kg, 135.89 ± 6.71 Bq/kg, 76.34 ± 5.32 Bq/kg and 1.05 ± 0.70 Bq/kg respectively. Furthermore, absorbed dose rate in air (D), radium equivalent activity (Ra e q), external hazard index (H e x), and annual effective dose rate (AEDout) of this area were also evaluated by using the mean values of specific activities of the 40 K , 226 R a and 232 T h. Moreover, the experimental results were also compared with Office of Atoms for Peace (OAP) research data, Thailand and global radioactivity measurement and evaluations. The radioactive contour maps of specific activities of natural and anthropogenic radionuclides from this study were created by using the program ArcGis Version 9.2

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

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

    International Nuclear Information System (INIS)

    Jesus, Gleyka J.D.; Chiozzini, Vitor G.; Saueia, Cátia H.R.; Nisti, Marcelo B.; Braga, Elisabete S.; Fávaro, Deborah I.T.; Universidade de São Paulo

    2017-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-07-01

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

  5. U-series radioactive disequilibria 238U-230Th-226Ra: discussions on sources and processes responsible for volcanism of the Andean cordillera and on the deglaciation in Iceland

    International Nuclear Information System (INIS)

    Chmeleff, J.

    2005-10-01

    Thanks to precise analyses of uranium series radioactive disequilibria, permitted by improvements of mass spectrometry data acquisition and optimization of chemistry, two questions were tackled and answers about the periods of glaciation in Iceland and the petrogenesis of Andean lavas were proposed. Two methods were used to date lava flows from the Reykjanes peninsula and the island of Heimaey, in Iceland, directly linked to the periods of deglaciation or reheating around the last ice age. An original method based on the use of segregation veins present in the lava flows has been developed. Thanks to the formation of this particular geological object this methods permits to be freed from xeno-crystals when using the internal isochron method in the 238 U- 230 Th system. Using this method some constraints are brought both on the quaternary geology of the area of Reykjavik and on the age of the end of the Wurm glaciation on Heirnaey. In parallel, due to the homogeneity of the historical and Holocene lavas of the Reykjanes peninsula, regarding the ( 230 Th/ 232 Th) and Th/U ratios, it is possible to derive the ( 230 Th/ 232 Th) ratio in time to determine the age of lava flows installed during the ice age. Thus we confirmed that the magnetic excursion recorded in the Skalamaelifell lava flow is most probably the same one as that of Laschamp-Olby and that at this time (approximately 48.000 years) the Reykjanes peninsula was entirely covered with a glacier. Thanks to this method the extent of the glacier was also constrained by dating of a picritic shield around 22.000 years, thus the peninsula has to be free of any ice cap despite the fact that glaciation is the most intense around this time.Then Andean arc magmas petrogenesis was constrained in time and space. Almost systematic excesses of 226 Ra compared to 230 Th in lavas of austral, southern and northern volcanic zones of the Andes (AVZ, SVZ and NVZ) constrain the ascending time from the source to the surface after

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

    Science.gov (United States)

    Szabo, B. J.

    1982-01-01

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

  7. The preparation of Th-232 target by molecular plating method

    International Nuclear Information System (INIS)

    Yang Chunli; Wu Junde; Su Shuxin; Yang Jingling

    2010-01-01

    In order to measure the reaction cross-section of 232 Th(α,2n) 234 U, the preparation of uniform and adherent Th-232 targets on Al foils of thickness 2-8 μm fixed on target frame by molecular plating technique from isopropanol was described. The substrate of electrolytic cell was reconstructed and the optimum acidity for the deposition of thorium were investigated. Through deposition yield analysis, the target thickness of 100- 200μg/cm 2 was determined. The α-spectrometry for the Th-232 targets shows a good energy resolution. (authors)

  8. Application of 234U/238U isotope ratio data for the study of geochemical problems associated with local water sources from Aguas da Prata (SP, Brazil)

    International Nuclear Information System (INIS)

    Bonotto, D.M.

    1982-01-01

    The uranium-238, uranium-234 and radon content of spring waters of Aguas da Prata (SP) - Platina, Paiol, Villela, Sao Bento, Prata-Radioativa, Prata-Nova, Boi, Vitoria and Prata-Antiga - was found; the activity ratio AR ( 234 U/ 238 U) was applied to the geochemistry of local water sources. The uranium analysis procedure consisted of the following steps: adition of 232 U- 228 Th spike to the samples, coprecipitation with iron, iron extraction with organic solvent, separation on anion-exchange resin, extraction with TTA, deposition on stainless steel disc and determination of uranium content by alpha spectrometry. The uranium-238 content changed from 0,10 to 11,56 ppb (average value = 2,3 ppb). The higher values were observed for the waters circulating through sandstones and the lower through volcanic rocks. The inverse correlation (r sub(s) =-0,76) between pH and uranium-238 content confirmed the contribution of this factor on its solubility. The significative correlation r sub(s) = 0,76 between dissolved oxygen and uranium-238 content also confirmed the higher uranium on the more oxidizing zones. The AR changed from 2,84 to 11,68 (average value = 6). These values defined the regional aquifer systems as mineralized in uranium. The higher AR were observed for the deep groundwaters and the lower for the shallow one. Because the 238 U→ 234 Th decay, the 234 Th ejection to the solution was confirmed as the most important factor responsible for the extreme observed isotopic fractionation. (Author) [pt

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

    Directory of Open Access Journals (Sweden)

    R. Léguillon

    2016-10-01

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

  10. Concentration of thorium isotopes and the activity ratios of 230Th/232Th and 228Th/232Th in seawater in the Pacific Ocean

    International Nuclear Information System (INIS)

    Miyake, Yasuo; Sugimura, Yukio; Yasujima, Tadahide.

    1978-01-01

    The concentration of thorium isotopes and the activity ratios of 230 Th/ 232 Th and 228 Th/ 232 Th in 500 l sea water samples collected in the Pacific Ocean were determined. Thorium isotopes were analyzed by alpha-ray spectrometry after separating them from other elements with an anion exchange resin. The average content of thorium ( 232 Th) of 0.9 ng l -1 was obtained in the open Pacific water. The average contents of 230 Th and 228 Th were 2.1 x 10 -2 pgl -1 and 1.2 agl -1 respectively. It was found that the ratios of 230 Th/ 232 Th and 228 Th/ 232 Th ranged respectively from 1.0 to 29, and from 0.4 to as high as 128. (author)

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

    Science.gov (United States)

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

    2018-03-01

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

  12. Natural radionuclides from U-238 and Th-232 series and inorganic chemical characterization of soil profiles and sediment cores of the TaiaÇUpeba Reservoir, SÃO Paulo, Brazil

    International Nuclear Information System (INIS)

    Souza, J.M.; Damatto, S.R.; Surkov, A.M.; Silva, A.R.; Maduar, M.F.; Gonçalves, P.N.; Leonardo, L.

    2017-01-01

    Taiaçupeba reservoir, located in the state of São Paulo, Brazil, belongs to Producer System of Alto Tietê (Sistema Produtor Alto Tietê) and it is responsible for water supply for about 3.1million of people. The water quality of a reservoir is very important, but this is reduced by the increase of environmental degradation of the soil around the reservoir and its different uses. The study of soil profiles and sediment cores is an important tool for understanding the geophysical and geochemical aspects of an aquatic ecosystem. The objective of this work was to present the natural radionuclides 238 U, 226 Ra, 210 Pb, 232 Th, 228 Th, 228 Ra and 40 K activity concentrations and also the inorganic chemical characterization of four soil profiles and four sediment cores collected in the area of influence area of Taiaçupeba reservoir. The analytical techniques, gamma spectrometry and instrumental neutron activation analysis were used in the determination. In the soil profiles the highest activity concentrations were obtained for the radionuclides 40 K and 228 Th and the lowest for 210 Pb; in the sediment cores the highest activity concentrations were obtained for the radionuclide 210 Pb and the lowest for 226 Ra and 228 Ra. For the inorganic chemical characterization the highest values obtained were for Na, As and Sb; in a sediment core a very high concentration was obtained for the element Zn indicating a probable accumulation of this element inside the reservoir; enrichment factor was used to evaluate a possible anthropic contamination in the soil and sediment at the margins of Taiaçupeba reservoir. (author)

  13. Determination of U, Th and K in bricks by gamma-ray spectrometry, X-ray fluorescence analysis and neutron activation analysis

    Science.gov (United States)

    Bártová, H.; Kučera, J.; Musílek, L.; Trojek, T.; Gregorová, E.

    2017-11-01

    Knowledge of the content of natural radionuclides in bricks can be important in some cases in dosimetry and application of ionizing radiation. Dosimetry of naturally occurring radionuclides in matter (NORM) in general is one of them, the other one, related to radiation protection, is radon exposure evaluation, and finally, it is needed for the thermoluminescence (TL) dating method. The internal dose rate inside bricks is caused mostly by contributions of the natural radionuclides 238U, 232Th, radionuclides of their decay chains, and 40K. The decay chain of 235U is usually much less important. The concentrations of 238U, 232Th and 40K were measured by various methods, namely by gamma-ray spectrometry, X-ray fluorescence analysis (XRF), and neutron activation analysis (NAA) which was used as a reference method. These methods were compared from the point of view of accuracy, limit of detection (LOD), amount of sample needed and sample handling, time demands, and instrument availability.

  14. 226Ra, 232Th and 40K analysis in sand samples from some beaches of Great Vitoria, Espirito Santo, Brazil: preliminary results

    International Nuclear Information System (INIS)

    Aquino, Reginaldo R.; Pecequilo, Brigitte R.S.

    2009-01-01

    The natural radioactivity in superficial beach sand samples of 7 beaches of Great Vitoria, metropolitan region of the State of Espirito Santo, southeast Brazil, was determined from the 226 Ra, 232 Th and 4 0 K contents. The assessed beaches were Manguinhos, Camburi, Praia do Canto, Curva da Jurema, Itapua, Setibao and Areia Preta. Three samples of each beach were sealed in standard 100 mL polyethylene flasks and stored in order to obtain secular equilibrium in the 238 U and 232 Th series. All samples were measured by high resolution gamma spectrometry and the spectra were analyzed with the WinnerGamma software. The 232 Th concentration was determined from the average concentrations of 228 Ac, 212 Pb and 212 Bi and the 226 Ra concentration was determined from the average concentrations of 214 Pb and 214 Bi. Preliminary results show concentrations varying from 9 Bq.kg -1 to 6035 Bq.kg -1 for 232 Th, from 4 Bq.kg -1 to 575 Bq.kg -1 for 226 Ra and from 13 Bq.kg -1 to 142 Bq.kg -1 for 40 K. Areia Preta beach shows the highest values for 232 Th, while the highest value for 226 Ra was observed for Camburi beach. High values of 40 K were observed for Curva da Jurema beach. (author)

  15. Mobility of 232Th and 210Po in red mud.

    Science.gov (United States)

    Hegedűs, Miklós; Tóth-Bodrogi, Edit; Jónás, Jácint; Somlai, János; Kovács, Tibor

    2018-04-01

    The valorization of industrial by-products such as red mud became a tempting opportunity, but the understanding of the risks involved is required for the safe utilization of these products. One of the risks involved are the elevated levels of radionuclides (in the 100-1300 Bq/kg range for both the 238 U and 232  Th decay chains, but usually lower than 1000 Bq/kg, which is the recommended limit for excemption or clearance according to the EU BSS released in 2013) in red mud that can affect human health. There is no satisfactory answer for the utilization of red mud; the main current solution is still almost exclusively disposal into a landfill. For the safe utilization and deposition of red mud, it is important to be able to assess the leaching behaviour of radionuclides. Because there is no commonly accepted measurement protocol for testing the leaching of radionuclides in the EU a combined measurement protocol was made and tested based on heavy metal leaching methods. The leaching features of red mud were studied by methods compliant with the MSZ-21470-50 Hungarian standard, the CEN/TS 14429 standard and the Tessier sequential extraction method for 232 Th and 210 Po. The leached solutions were taken to radiochemical separation followed by spontaneous deposition for Po and electrodeposition for Th. The 332 ± 33 Bq/kg 232 Th content was minimally mobile, 1% became available for distilled water 1% and 6% for Lakanen-Erviö solution; the Tessier extraction showed minimal mobility in the first four steps, while more than 85% remained in the residue. The 210 Po measurements had a severe disturbing effect in many cases, probably due to large amounts of iron present in the red mud, from the 310 ± 12 Bq/kg by aqua regia digestion, distilled water mobilized 23%, while Lakanen-Erviö solution mobilized ∼13%. The proposed protocol is suitable for the analysis of Th and Po leaching behaviour. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. 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

  17. Electrodisintegration of 232Th by neutron emission

    International Nuclear Information System (INIS)

    Terremoto, L.A.A.

    1986-01-01

    The one neutron decay of the giant electric quadrupole resonance was studied by means of electrodisintegration and photodisintegration reactions. The separation of the multipole components of the photonuclear cross section σ γ,n (E) in 232 90 Th was also performed. The 232 Th(e,n) 231 Th cross section and the 232 Th(B,n) 231 Th bremsstrahlung yield were measured in the incident electron energy range 8-60 MeV and 25-60 MeV, respectively. These measurements have been performed using the electron beam of the Linear Accelerator of the IFUSP and the experimental technique of activation analysis. The virtual photon spectra corrected for nuclear finite size in the analysis of the experimental data obtained in order to separate the multipole components of the photonuclear cross section, was used. An electric dipole component σ EL γ,n (E) that exhausts (60+-7)% of the El sum rule (integrated uσ to 16,5 MeV) was shown. This result is in agreement with the one Obtained in experiments where monoenergetic photons were used. An electric quadrupole component σ E2 γ,n (E) whose value corresponds to (32+-6)% of the E2 sum rule, was also obtained. (author) [pt

  18. Natural radionuclides from U-238 and Th-232 series and inorganic chemical characterization of soil profiles and sediment cores of the TaiaÇUpeba Reservoir, SÃO Paulo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Souza, J.M.; Damatto, S.R.; Surkov, A.M.; Silva, A.R.; Maduar, M.F.; Gonçalves, P.N., E-mail: jmarques@ipen.br, E-mail: damatto@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Leonardo, L. [Centro Universitário São Camilo (Campus Ipiranga), São Paulo, SP (Brazil)

    2017-07-01

    Taiaçupeba reservoir, located in the state of São Paulo, Brazil, belongs to Producer System of Alto Tietê (Sistema Produtor Alto Tietê) and it is responsible for water supply for about 3.1million of people. The water quality of a reservoir is very important, but this is reduced by the increase of environmental degradation of the soil around the reservoir and its different uses. The study of soil profiles and sediment cores is an important tool for understanding the geophysical and geochemical aspects of an aquatic ecosystem. The objective of this work was to present the natural radionuclides {sup 238}U, {sup 226}Ra, {sup 210}Pb, {sup 232}Th, {sup 228}Th,{sup 228}Ra and {sup 40}K activity concentrations and also the inorganic chemical characterization of four soil profiles and four sediment cores collected in the area of influence area of Taiaçupeba reservoir. The analytical techniques, gamma spectrometry and instrumental neutron activation analysis were used in the determination. In the soil profiles the highest activity concentrations were obtained for the radionuclides {sup 40}K and {sup 228}Th and the lowest for {sup 210}Pb; in the sediment cores the highest activity concentrations were obtained for the radionuclide {sup 210}Pb and the lowest for {sup 226}Ra and {sup 228}Ra. For the inorganic chemical characterization the highest values obtained were for Na, As and Sb; in a sediment core a very high concentration was obtained for the element Zn indicating a probable accumulation of this element inside the reservoir; enrichment factor was used to evaluate a possible anthropic contamination in the soil and sediment at the margins of Taiaçupeba reservoir. (author)

  19. Cost-based optimizations of power density and target-blanket modularity for 232Th/233U-based ADEP

    International Nuclear Information System (INIS)

    Krakowski, R.A.

    1995-01-01

    A cost-based parametric systems model is developed for an Accelerator-Driven Energy Production (ADEP) system based on a 232 Th/ 233 U fuel cycle and a molten-salt (LiF/BeF 2 /ThF 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, 233 U breeding rate, and fission product transmutation capacity

  20. Microscopic structure of superdeformed states in Th, U, Pu and Cm isotopes with Gogny force

    International Nuclear Information System (INIS)

    Girod, M.; Delaroche, J.P.; Romain, P.; Libert, J.

    2002-01-01

    The structure properties of the even-even nuclei 226, 228, 230, 232, 234 Th, 230, 232, 234, 236, 238, 240 U, 240, 242, 244, 246 Pu, and 242, 244, 246, 248 Cm have been investigated at normal and superdeformed shapes in microscopic mean-field calculations based on Gogny force. Collective levels are predicted from constrained Hartree-Fock-Bogoliubov and configuration mixing calculations. Two quasiparticle states are also predicted from blocking calculations for neutron and proton configurations. Predictions are shown and compared with experimental data at superdeformed shapes. (orig.)

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  2. Natural radioactivity (226Ra, 232Th and 40K) and assessment of radiological hazards in the Kestanbol granitoid, Turkey.

    Science.gov (United States)

    Canbaz, Buket; Cam, N Füsun; Yaprak, Günseli; Candan, Osman

    2010-09-01

    The surveys of natural gamma-emitting radionuclides in rocks and soils from the Ezine plutonic area were conducted during 2007. Direct dose measurement using a survey meter was carried out simultaneously. The present study, which is part of the survey, analysed the activity concentrations of (238)U, (232)Th and (40)K in granitoid samples from all over the region by HPGe gamma spectrometry. The activity concentrations of (226)Ra ranged from 94 to 637 Bq kg(-1), those of (232)Th ranged from 120 to 601 Bq kg(-1)and those of (40)K ranged from 1074 to 1527 Bq kg(-1) in the analysed rock samples from different parts of the pluton. To evaluate the radiological hazard of the natural radioactivity in the samples, the absorbed dose rate (D), the annual effective dose rate, the radium equivalent activity (Ra(eq)) and the external (H(ex)) hazard index were calculated according to the UNSCEAR 2000 report. The thorium-to-uranium concentration ratios were also estimated.

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

    International Nuclear Information System (INIS)

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

    1982-01-01

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

  4. Microscopic structure of superdeformed states in Th, U, Pu and Cm isotopes with Gogny force

    Energy Technology Data Exchange (ETDEWEB)

    Girod, M.; Delaroche, J.P.; Romain, P. [CEA/DIF, DPTA/SPN, Boite Postale 12, 91680 Bruyeres-le-Chatel (France); Libert, J. [Institut de Physique Nucleaire Centre National de la Recherche Scientifique-IN2P3, F-91406 Orsay (France)

    2002-10-01

    The structure properties of the even-even nuclei {sup 226,} {sup 228,} {sup 230,} {sup 232,} {sup 234}Th, {sup 230,} {sup 232,} {sup 234,} {sup 236,} {sup 238,} {sup 240}U, {sup 240,} {sup 242,} {sup 244,} {sup 246}Pu, and {sup 242,} {sup 244,} {sup 246,} {sup 248}Cm have been investigated at normal and superdeformed shapes in microscopic mean-field calculations based on Gogny force. Collective levels are predicted from constrained Hartree-Fock-Bogoliubov and configuration mixing calculations. Two quasiparticle states are also predicted from blocking calculations for neutron and proton configurations. Predictions are shown and compared with experimental data at superdeformed shapes. (orig.)

  5. Status of thorium cycle nuclear data evaluations: Comparison of cross-section line shapes of JENDL-3 and ENDF-B-VI files for 230Th, 232Th, 231Pa, 233Pa, 232U, 233U and 234U

    International Nuclear Information System (INIS)

    Ganesan, S.; McLaughlin, P.K.

    1992-02-01

    Since 1990, one of the most interesting developments in the field of nuclear data for nuclear technology applications is that several new evaluated data files have been finalized and made available to the International Atomic Energy Agency (IAEA) for distribution to its Member States. Improved evaluated nuclear data libraries such as ENDF/B-VI from the United States and JENDL-3 from Japan were developed over a period of 10-15 years. This report is not an evaluation of the evaluations. The report as presented here gives a first look at the cross section line shapes of the isotopes that are important to the thorium fuel cycle derived from the two recently evaluated data files: JENDL-3 and ENDF/B-VI. The basic evaluated data files JENDL-3 and ENDF/B-VI were point-processed successfully using the codes LINEAR and RECENT. The point data were multigrouped in three different group structures using the GROUPIE code. Graphs of intercomparisons of cross section line shapes of JENDL-3 and ENDF/B-VI are presented in this paper for the following isotopes of major interest to studies of the thorium fuel cycle: 230 Th, 232 Th, 231 Pa, 233 Pa, 232 U, 233 U and 234 U. Comparisons between JENDL-3 and ENDF/B-VI which were performed at the point and group levels show large discrepancies in various cross sections. We conclude this report with a general remark that it is necessary to perform sensitivity studies to assess the impacts of the discrepancies between the two different sets of data on calculated reactor design and safety parameters of specific reactor systems and, based on the results of such sensitivity studies, to undertake new tasks of evaluations. (author). 2 refs, 245 figs, 8 tabs

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

    Marko Cerne; Borut Smodis; Marko Strok; Radojko Jacimovic

    2010-01-01

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

  8. Nondestructive analysis for 232U and decay progeny in animal tissues

    International Nuclear Information System (INIS)

    Ballou, J.E.; Wogman, N.A.

    1977-01-01

    Direct determination of 232 U and its decay products in animal tissues appears to be feasible using an intrinsic Ge(Li) diode detector (for energies of 5-100 keV) and a NaI(Tl) anticoincidence-shielded Ge(Li) diode for higher-energy gamma photons. The detection sensitivity for 232 U and 228 Th is 0.03 and 0.01 nCi, respectively, using a 300-min counting time

  9. Uranium-238 and thorium-232 series concentrations in soil, radon-222 indoor and drinking water concentrations and dose assessment in the city of Alameda, Chihuahua, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Colmenero Sujo, L.; Montero Cabrera, M.E. E-mail: elena.montero@cimav.edu.mx; Villalba, L.; Renteria Villalobos, M.; Torres Moye, E.; Garcia Leon, M.; Garcia-Tenorio, R.; Mireles Garcia, F.; Herrera Peraza, E.F.; Sanchez Aroche, D

    2004-07-01

    High-resolution gamma spectrometry was used to determine the concentration of {sup 40}K, {sup 238}U and {sup 232}Th series in soil samples taken from areas surrounding the city of Aldama, in Chihuahua. Results of indoor air short-time sampling, with diffusion barrier charcoal detectors, revealed relatively high indoor radon levels, ranging from 29 to 422 Bq/m{sup 3}; the radon concentrations detected exceeded 148 Bq/m{sup 3} in 76% of the homes tested. Additionally, liquid scintillation counting showed concentrations of radon in drinking water ranging from 4.3 to 42 kBq/m{sup 3}. The high activity of {sup 238}U in soil found in some places may be a result of the uranium milling process performed 20 years ago in the area. High radon concentrations indoor and in water may be explained by assuming the presence of uranium-bearing rocks underneath of the city, similar to a felsic dike located near Aldama. The estimated annual effective dose of gamma radiation from the soil and radon inhalation was 3.83 mSv.

  10. Uranium-238 and thorium-232 series concentrations in soil, radon-222 indoor and drinking water concentrations and dose assessment in the city of Aldama, Chihuahua, Mexico.

    Science.gov (United States)

    Colmenero Sujo, L; Montero Cabrera, M E; Villalba, L; Rentería Villalobos, M; Torres Moye, E; García León, M; García-Tenorio, R; Mireles García, F; Herrera Peraza, E F; Sánchez Aroche, D

    2004-01-01

    High-resolution gamma spectrometry was used to determine the concentration of 40K, 238U and 232Th series in soil samples taken from areas surrounding the city of Aldama, in Chihuahua. Results of indoor air short-time sampling, with diffusion barrier charcoal detectors, revealed relatively high indoor radon levels, ranging from 29 to 422 Bq/m3; the radon concentrations detected exceeded 148 Bq/m3 in 76% of the homes tested. Additionally, liquid scintillation counting showed concentrations of radon in drinking water ranging from 4.3 to 42 kBq/m3. The high activity of 238U in soil found in some places may be a result of the uranium milling process performed 20 years ago in the area. High radon concentrations indoor and in water may be explained by assuming the presence of uranium-bearing rocks underneath of the city, similar to a felsic dike located near Aldama. The estimated annual effective dose of gamma radiation from the soil and radon inhalation was 3.83 mSv.

  11. Distribution of naturally occurring radionuclides (U, Th) in Timahdit's black shale (Morocco)

    International Nuclear Information System (INIS)

    Galindo, C.; Mougin, L.; Nourreddine, A.; Fakhi, S.

    2006-01-01

    Attention has been recently focused on the use of Moroccan's black shale as the raw material for production of a new type of adsorbents. The purpose of the present work was to characterize a black shale specimen, collected in the region of Timahdit, in terms of the total uranium and thorium contents, measurements of some geochemically important elements (Al, Fe, Si, K, Mn, P, Ca), and XRD/SEM analysis. Selective leaching procedure, followed by radiochemical purification and alpha-counting, was also performed to assess the distribution of 238 U, 234 U, 235 U, 232 Th, 228 Th, 230 Th in the main structures. It was found that calcite, dolomite, quartz, clays constitute the main bulk composition of inorganic matrix. Organic matter counts for at least 15 wt. % of the sample. As in most other organic rich rocks, uranium is highly enriched in the black shale. It was interpreted to have been concentrated over a long period of time under anaerobic environment. This actinide is associated predominantly with humic acids, the precursor of kerogen. An integrated isotopic approach points out its mobilization from these humic acids to carbonates and apatite phases. The radionuclide that is the less mobile in this environment is 232 Th, as was expected from its chemical properties, and in agreement with the most common view in the literature. It is partitioned between silicate minerals (49%), pyrite and kerogen (51%). Speciation, chemical behaviour of uranium and thorium and alpha decay related processes are widely responsible for disequilibria in the uranium decay series. (author)

  12. Measurement of {sup 232}Th(n, 5nγ) cross sections from 29 MeV to 42 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Kerveno, M.; Baumann, P.; Dessagne, P.; Rudolf, G. [Universite de Strasbourg, IPHC, Strasbourg (France); CNRS, UMR7178, Strasbourg (France); Nolte, R.; Reginatto, M. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Jericha, E. [Technische Universitaet Wien, Atominstitut, Wien (Austria); Jokic, S.; Lukic, S. [Vinca Institute of Nuclear Sciences, Belgrade (Serbia); Koning, A.J. [Nuclear Research and Consultancy Group, Petten (Netherlands); Meulders, J.P. [Institut de Physique Nucleaire, Louvain-la-Neuve (Belgium); Nachab, A. [Universite Cadi Ayyad, Departement de physique, Faculte Poly-disciplinaire de Safi, Safi (Morocco); Pavlik, A. [Faculty of Physics, University of Vienna, Wien (Austria)

    2014-10-15

    The excitation function of the reaction {sup 232} Th(n, 5nγ){sup 228} Th from 29 to 42 MeV has been measured for the first time at the quasi-monoenergetic neutron beam of the UCL cyclotron CYCLONE employing the {sup 7}Li(p,n) source reaction. Taking advantage of the good energy resolution of the planar High-Purity Germanium (HPGe) detectors, prompt γ-ray spectroscopy was used to detect the γ-rays resulting from the decay of excited states of nuclei created by the (n,xn) reactions. The neutron beam was characterized by a combination of time of flight measurements carried out using a liquid scintillation detector and a {sup 238}U fission ionization chamber. Fluence measurements were performed using a proton recoil telescope. The results are compared with TALYS-1.4 code calculations. (orig.)

  13. Optimization of binary breeder reactor IV - Conception of mixed fuel at central part of the core

    International Nuclear Information System (INIS)

    Dias, A.F.; Ishiguro, Y.

    1986-04-01

    Neutronic characteristics of some LMFBRs are analized for a fueling mode that is different from those reported previously. In an inner part of the core both 233 U/ 232 Th and Pu/U assemblies are placed while the outer zone is fueled with Pu/U assemblies. Both oxide metal fuels and 232 Th and 238 U blankets are considered. (Author) [pt

  14. Distribution of activity concentrations of {sup 238}U and {sup 232}Th in soil samples from Minas Gerais state; Distribuicao das concentracoes de atividade de {sup 238}U e {sup 232}Th em amostras de solo do Estado de Minas Gerais

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, C.M.; Rodrigues, P.C.H.; Carvalho Filho, C.A.; Feliciano, V.M.D., E-mail: Patricia.fernandes@meioambiente.mg.gov.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Fernandes, P.R.M., E-mail: cmp@cdtn.br, E-mail: pchr@cdtn.br, E-mail: cacf@cdtn.br, E-mail: vmfj@cdtn.br [Fundacao Estadual do Meio Ambiente (FEAM), Belo Horizonte, MG (Brazil)

    2016-07-01

    Soil contamination by radionuclides, heavy metal, pesticides, among others, threatens ecosystems and human health. Environmental monitoring bodies and agencies need reference values for these contaminants in order to assess the impacts of anthropogenic activities on soil contamination. Quality Reference Values (QRVs) reflect the natural concentrations of contaminants in soils without anthropic interference and must be regionally established. The aim of this study was the determination of natural concentrations and quality reference values for U and Th in soils from Minas Gerais State, Brazil. A large variation of the natural activity concentration of these radionuclides in soil was observed. The QRV for U was 86.5 Bq kg{sup -1} and 90.81 Bq kg{sup -1} for Th. Statistical analysis showed that the two elements have a positive correlation with the clay and organic matter content in soil, and with the soil orders Ultisol and Inceptisol. Uranium shows a strong correlation with As, Sb, Se and Hg, while Thorium does not show correlation with any of the trace elements. (author)

  15. 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.

  16. 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.

  17. Consultants' Meeting on Review Benchmarking of Nuclear Data for the Th/U Fuel Cycle. Summary Report

    International Nuclear Information System (INIS)

    Capote Noy, R.

    2011-02-01

    A summary is given of the Consultants' Meeting (CM) on Review and Benchmarking of Nuclear Data for the Th/U Fuel Cycle. An IAEA Coordinated Research Project (CRP) on 'Nuclear Data for Th/U Fuel Cycle' was concluded in 2005. The CRP activities resulted in new evaluated nuclear data files for 232 Th, 231 , 233 Pa (later adopted for the ENDF/B-VII.0 library) and improvements to existing evaluations for 232 , 233 , 234 , 236 U. Available nuclear data evaluations for 230 - 232 Th, 231,233 Pa and 232 , 233 , 234 U were reviewed including ROSFOND2010, CENDL-3.1, JENDL-4, JEFF-3.1.1, MINSKACT, and ENDF/B-VII.0 libraries. Benchmark results of available evaluations for 232 Th and 233 U were also discussed. (author)

  18. Seasonal variations of total 234Th and dissolved 238U concentration activities in surface water of Bransfield Strait, Antarctica, from March to October 2011

    International Nuclear Information System (INIS)

    Lapa, Flavia V.; Oliveira, Joselene de; Costa, Alice M.R.; Braga, Elisabete S.

    2013-01-01

    In this study the naturally occurring radionuclides 234 Th and 238 U were used to investigate the magnitude of upper ocean particulate organic carbon export in Bransfield Strait, Southern Ocean. This region is the largest oceanic high-nitrate low-chlorophyll (HNLC) area in the world and is known to contribute to regulate of the atmospheric CO 2 via the biological pump. Due to its different geochemical behavior in seawater, the resulting U/Th disequilibria can be easily used to constrain the transport rates of particles and reaction processes between solution and particulate phases. Sampling occurred during the summer (March and November) 2011. Total 234 Th activities in surface seawater samples ranged from 1.3 to 3.7 dpm L -1 (station EB 011) during March/11 campaign, while in October/11 total 234 Th activity concentrations varied from 1.4 to 2.9 dpm L -1 . Highest total 234 Th activities were found late in the austral summer season. Activity concentrations of dissolved 238 U in surface seawater varied from 2.1 to 2.4 dpm L -1 . Taking into account all sampling stations established in March and October/11 the relative variability of total 234 Th distribution was 22%. (author)

  19. Measurement of the fission cross section induced by fast neutrons of the {sup 232}Th/{sup 233}U nuclei within the innovating fuel cycles framework; Mesure de la section efficace de fission induite par neutrons rapides des noyaux {sup 232}Th/{sup 233}U dans le cadre des cycles de combustible innovants

    Energy Technology Data Exchange (ETDEWEB)

    Grosjean, C

    2005-03-15

    The thorium-U{sup 233} fuel cycle might provided safer and cleaner nuclear energy than the present Uranium/Pu fuelled reactors. Over the last 10 years, a vast campaign of measurements has been initiated to bring the precision of neutron data for the key nuclei (Th{sup 232}, Pa{sup 233} and U{sup 233}) at the level of those for the U-Pu cycle. This is the framework of these measurements, the energy dependent neutron induced fission cross section of Th{sup 232} and U{sup 233} has been measured from 1 to 7 MeV with a target accuracy lesser than 5 per cent. These measurements imply the accurate determination of the fission rate, the number of the target nuclei as well as the incident neutron flux impinging on the target, the latter has been obtained using the elastic scattering (n,p). The cross section of which is very well known in a large neutron energy domain ({approx} 0,5 % from 1 eV to 50 MeV) compared to the U{sup 235}(n,f) reaction. This technique has been applied for the first time to the Th{sup 232}(n,f) and U{sup 233}(n,f) cases. A Hauser-Feshbach statistical model has been developed. It consists of describing the different decay channels of the compound nucleus U{sup 234} from 0,01 to 10 MeV neutron energy. The parameters of this model were adjusted in order to reproduce the measured fission cross section of U{sup 233}. From these parameters, the cross sections from the following reactions could be extracted: inelastic scattering U{sup 233}(n,n'), radiative capture U{sup 233}(n,{gamma}) and U{sup 233}(n,2n). These cross sections are still difficult to measure by direct neutron reactions. The calculated values have allowed us to fill the lack of experimental data for the major fissile nucleus of the thorium cycle. (author)

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

    International Nuclear Information System (INIS)

    Iturbe G, J.L.

    1990-02-01

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

  1. Analysis of radon, uranium 238 and thorium 232 in potable waters: Dose to adult members of the Moroccan urban population

    International Nuclear Information System (INIS)

    Misdaq, M.A.; Ouabi, H.; Merzouki, A.

    2007-01-01

    Uranium ( 238 U) and thorium ( 232 Th) concentrations as well as radon ( 222 Rn) and thoron ( 220 Rn) alpha-activities per unit volume have been measured inside various potable water samples collected from nineteen cities in Morocco by using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). Measured radon alpha-activities ranged from (0.37 ± 0.02) Bq l -1 to (13.6 ± 1.10) Bq l -1 for the potable water samples studied. Alpha-activities due to radon from the ingestion of the studied potable water samples were determined in different compartments of the gastrointestinal system by using the ICRP compartmental model for radon. Annual committed equivalent doses due to radon were evaluated in the gastrointestinal compartments from the ingestion of the potable water samples studied. The influence of the target tissue mass, radon intake and alpha-activity integral due to radon on the annual committed equivalent doses in the gastrointestinal compartments was investigated

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  3. 187Re - 232Th - 238U nuclear geochronometry: constraining magmatism in East-Antarctica and the break-up of Gondwana

    Science.gov (United States)

    Roller, Goetz

    2017-04-01

    187Re - 232Th - 238U nuclear geochronometry is a new dating method for astronomy, earth and planetary sciences [1-4]. Nucleogeochronometric Rhenium-Osmium two-point-isochron (TPI) ages are calculated using a nuclear geochronometer as one data point in a two-point-isochron diagram [5-7]. The IVREA chronometer, for example, is one of five terrestrial nuclear geochronometers identified so far [8]. Here, it is used to constrain the magmatism of the Ferrar flood basalt province, which has been related to continental rifting and the break-up of Gondwana in the Jurassic.TPI ages for seven (basaltic) andesite whole rock samples from the Prince Albert Mountains (Victoria Land, Antarctica) are calculated. An isochron age of 172 ± 5 Ma (187Os/188Osi = 0.194 ± 0.023) has previously been published for these rocks [9]. Initial TPI 187Os/188Osi ratios show only minor scatter between 187Os/188Osi = 0.2149 ± 0.0064 and 187Os/188Osi = 0.22231 ± 0.00080, in agreement with the enigmatic, suprachondritic 187Os/188Osi = 0.194 ± 0.023 from the isochron [9]. TPI ages for the Mount Joyce samples range from 125.4 ± 9.9 Ma to 139 ± 17 Ma and thus constrain the youngest magmatic event(s) in the Transantarctic Mountains. For the Thumb Point basalt, a TPI age of 219 ± 81 Ma is calculated. Despite of its large uncertainty, the age itself is in agreement with the Triassic 224 Ma and 240 Ma events reported from North Patagonia [10]. The TPI age of 186.1 ± 8.1 Ma from the Ricker Hill basalt can be clearly distinguished from the Mount Murray TPI age of 158 ± 14 Ma, while at Brimstone Peak two TPI age groups of 155 ± 14 Ma and 175.3 ± 3.1 Ma are observed. From this it may be concluded that the seven TPI ages indicate episodic magmatic activity in East-Antarctica between 125 Ma and 219 Ma, leading to the break-up of Gondwana. This picture is consistent with the geochronology of the Antarctic Peninsula, Patagonia, the Karoo and the Ferrar mafic rocks [10]. Thus, besides constraining

  4. Concentration of 232Th, 230Th and 228Th in various tissues of Japanese subjects

    International Nuclear Information System (INIS)

    Takizawa, Y.; Qingmei, H.; Hisamatsu, S.; Abe, T.

    1997-01-01

    The concentration of 232 Th, 230 Th and 228 Th in various human tissues of Japanese subjects obtained at autopsies are reported. The tissue samples were weighed, spiked with 234 Th tracer and ashed by acid. The solution was dried on a hot-plate. Separation of thorium radionuclides was accomplished through cation-exchange resin chromatography and electrodeposition. The concentrations of thorium isotopes were measured by α-spectrometry. Thorium-232 and 230 Th concentrations were found to be highest in lung, followed by bone. The maximum concentration of 228 Th was in bone. The lowest concentrations of thorium isotopes were in muscle. (author)

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

    International Nuclear Information System (INIS)

    Kratz, J.V.

    1980-03-01

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

  6. 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)

  7. Impulse transfer and light particles emission during the reaction α + 232Th at 70 MeV/u

    International Nuclear Information System (INIS)

    Nguyen, M.S.

    1988-02-01

    We have measured during the reaction 4 He + 232 Th at 70 MeV/u the angular correlation of heavy fragments of fission, the inclusive energy spectra of light particles (p, d, t, 3 He and α) and triple coincidence between two fission fragments and a light ejectile. Energy spectra show an evaporation component at low energy, a component of projectile fragmentation at energy equivalent to beam velocity and an intermediate component attributed to pre-equilibrium emission. The analysis of the correlation between linear momentum transfer to the fissioning nucleus and the characteristics of the ejectile in coincidence shows a phenomenon of incomplete massive transfer. We run an Intra-Nuclear Cascade (INC) computation to reproduce ejectile energy spectra, but the agreement with experiment was very bad. We conclude to the impossibility to apply INC computation at intermediate energy of 70 MeV/u. We also applied Distorted Wave Born Approximation (DWBA) for direct transfer reaction extended to continuum states: but the agreement with experiment was again deceiving. Finally, we used an analysis by moving sources for which we propose a model of generalized fragmentation giving a continuous representation of the emission source phenomenon from low energy up to high energy [fr

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

    Energy Technology Data Exchange (ETDEWEB)

    Iturbe G, J L

    1990-02-15

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

  9. Extension of the Th-232 burnup chain in the WIMSD/4 program library

    International Nuclear Information System (INIS)

    Caldeira, A.D.

    1991-07-01

    The Th-232 burnup chain was extended through U-236, in the WIMSD/4 program library. The evolution of the values of k i nf and U-235 number density, as function of time, for the modified TRX1 problem, calculated with the new library, shows an improvement in the results when compared with LEOPARD program. (author)

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

    International Nuclear Information System (INIS)

    Turnewitsch, R.; Turnewitsch, R.; Waniek, J.J.; Reyss, J.L.; Nycander, J.; Lampitt, R.S.

    2008-01-01

    Residual flow, baro-tropic tides and internal (baro-clinic) tides interact in a number of ways with kilometer-scale sea floor topography such as abyssal hills and sea mounts. Because of their likely impact on vertical mixing such interactions are potentially important for ocean circulation and the mechanisms and the geometry of these interactions are a matter of ongoing studies. In addition, very little is known about how these interactions are reflected in the sedimentary record. This multi-year study investigates if flow/topography interactions are reflected in distributional patterns of the natural short-lived (half-life: 24.1 d) particulate-matter tracer 234 Th relative to its conservative (non-particle-reactive) and very long-lived parent nuclide 238 U. The sampling sites were downstream of, or surrounded by, fields of short sea mounts and, therefore, very likely to be influenced by nearby flow/topography interactions. At the sampling sites between about 200 and 1000 m above the sea floor recurrent 'fossil' disequilibria were detected. 'Fossil' disequilibria are defined by clearly detectable 234 Th/ 238 U disequilibria (total 234 Th radioactivity ≤ 238 U radioactivity, indicating a history of intense particulate 234 Th scavenging and particulate-matter settling from the sampled parcel of water) and conspicuously low particle-associated 234 Th activities. 'Fossil' disequilibria were centered at levels in the water column that correspond to the average height of the short sea mounts near the sampling sites. This suggests the 'fossil' disequilibria are formed on the sea mount slopes. Moreover, the magnitude of the 'fossil' disequilibria suggests that the slopes of the short sea mounts in the study region are characterized by particularly vigorous fluid dynamics. Since 'fossil' disequilibria already occurred at ∼ O (1-10 km) away from the sea mount slopes it is likely that these vigorous fluid dynamics rapidly decay away from the slopes on scales of O (1-10 km

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

    Science.gov (United States)

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

    2016-12-01

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

  12. Investigation of the 232Th neutron cross-sections in resonance energy range

    International Nuclear Information System (INIS)

    Grigoriev, Yu.V.; Kitaev, V.Ya.; Sinitsa, V.V.; Zhuravlev, B.V.; Borzakov, S.B.; Faikov-Stanchik, H.; Ilchev, G.L.; Panteleev, Ts.Ts.; Kim, G.N.

    2001-01-01

    The alternative path in the development of atomic energy is the uranium-thorium cycle. In connection with this, the measurements of the 232 Th neutron capture and total cross-sections and its resonance self-shielding coefficients in resonance energy range are necessary because of their low accuracy. In this work, the results of the investigations of the thorium-232 neutron cross-sections are presented. The measurements have been carried out on the gamma-ray multisection liquid detector and neutron detector as a battery of boron counters on the 120 m flight path of the pulsed fast reactor IBR-30. As the filter samples were used the metallic disks of various thickness and diameter of 45 mm. Two plates from metallic thorium with thickness of 0.2 mm and with the square of 4.5x4.5 cm 2 were used as the radiator samples. The group neutron total and capture cross-sections within the accuracy of 2-7% in the energy range of (10 eV-10 keV) were obtained from the transmissions and the sum spectra of g-rays from the fourth multiplicity to the seventh one. The neutron capture group cross-sections of 238 U were used as the standard for obtaining of thorium ones. Analogous values were calculated on the GRUCON code with the ENDF/B-6, JENDL-3 evaluated data libraries. Within the limits of experimental errors an agreement between the experiment and calculation is observed, but in some groups the experimental values are larger than the calculated ones. (author)

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

    OpenAIRE

    Bory?o, Alicja; Skwarzec, Bogdan

    2014-01-01

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

  14. Collection and evaluation of nuclear data of Th-232

    International Nuclear Information System (INIS)

    Osawa, Takaaki

    1979-01-01

    Present status of the requirement to and measurement and evaluation of the nuclear data of Th-232 is presented. The accuracy and energy range of the observed data at present are not enough to the demand from reactor engineering. The data of total cross-section are given in the energy range from 1.5 to 15 MeV from the data by Foster and Fasoli. The data by Uttley for the energy less than 1.5 MeV were accepted. Recently, Whalen and Kobayashi presented new data. Optical potential parameters were deduced. Re-normalization of the capture cross-sections of Th-232 was made on the basis of the evaluated values by Matsunobu and by Kanda. The values are a little smaller than the values in ENDF/B-4. Fission cross-sections were given by Henkel up to 9 MeV, and by Rago and Pankratov for the energy range above 9 MeV. Recently, Behrens presented new data for wide energy range. The accuracy of the measured cross-sections of inelastic scattering is not enough for reactor design. The accurate values of the cross-sections of (n, 2n) reaction of Th-232 have been demanded. Resonance parameters have been measured for wide energy range. In the energy range of thermal neutrons, the capture cross-section is about 7.4 barn. The characteristics of velocity dependence of the capture cross-section in this range should be investigated. (Kato, T.)

  15. Study of the uranium availability through the research method Th/U

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, Zahily Herrero; Santos Junior, Jose Araujo dos; Amaral, Romilton dos Santos; Santos, Josineide Marques do Nascimento; Damascena, Kennedy Francys Rodrigues; Medeiros, Nilson Vicente da Silva; Maciel Neto, Jose de Almeida, E-mail: zahily1985@gmail.com, E-mail: jaraujo@ufpe.br, E-mail: romilton@ufpe.br, E-mail: neideden@hotmail.com, E-mail: kennedy.eng.ambiental@gmail.com, E-mail: nvsmedeiros@gmail.com, E-mail: profjosemaciel@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Centro de Tecnologia e Geociencias. Departamento de Energia Nuclear; Alvarez, Juan Reinaldo Estevez, E-mail: jestevez@ceaden.cu [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Havana (Cuba); Silva, Alberto Antonio da, E-mail: alberto.silva@barreiros.ifpe.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco (IFPE), Barreiros, PE (Brazil)

    2015-07-01

    The uranium and thorium, precursors of the main natural radioactive series, have different concentrations in the Earth's crust. The ratio Th/U has been used as an indicator of oxidizing and reducing conditions, whose factors suggest availability of uranium to displacement in the environment and incorporations in different matrices. This parameter become essential to determine possible conditions of availability by the chemical form and incorporation in the food chain. The state of Paraiba, in northeastern Brazil, has a uranium deposits located in Sao Jose de Espinharas, where there are agricultural practices in areas surrounding the deposit of natural uranium. The Environmental Monitoring Program and Radioecological, making it an area that offers all the features for research mobility of uranium, chemical form and availability of incorporation, in addition to understanding the kinetics and transport of this natural radionuclide in the environment. Soil samples were collected from agricultural areas, close to the uraniferous occurrences where the samples were analyzed in the Laboratorio de Radioecologia e Controle Ambiental (LARCA) of the Departamento de Energia Nuclear at the Universidade Federal de Pernambuco (UFPE) by High Resolution Gamma Spectrometry, obtaining the experimental activities of {sup 238}U and {sup 232}Th using indirect gamma measures. The obtained findings show that the ratio Th/U varied from 0.11 to 1.33, with an average of 0.69. (author)

  16. Study of the uranium availability through the research method Th/U

    International Nuclear Information System (INIS)

    Fernandez, Zahily Herrero; Santos Junior, Jose Araujo dos; Amaral, Romilton dos Santos; Santos, Josineide Marques do Nascimento; Damascena, Kennedy Francys Rodrigues; Medeiros, Nilson Vicente da Silva; Maciel Neto, Jose de Almeida; Silva, Alberto Antonio da

    2015-01-01

    The uranium and thorium, precursors of the main natural radioactive series, have different concentrations in the Earth's crust. The ratio Th/U has been used as an indicator of oxidizing and reducing conditions, whose factors suggest availability of uranium to displacement in the environment and incorporations in different matrices. This parameter become essential to determine possible conditions of availability by the chemical form and incorporation in the food chain. The state of Paraiba, in northeastern Brazil, has a uranium deposits located in Sao Jose de Espinharas, where there are agricultural practices in areas surrounding the deposit of natural uranium. The Environmental Monitoring Program and Radioecological, making it an area that offers all the features for research mobility of uranium, chemical form and availability of incorporation, in addition to understanding the kinetics and transport of this natural radionuclide in the environment. Soil samples were collected from agricultural areas, close to the uraniferous occurrences where the samples were analyzed in the Laboratorio de Radioecologia e Controle Ambiental (LARCA) of the Departamento de Energia Nuclear at the Universidade Federal de Pernambuco (UFPE) by High Resolution Gamma Spectrometry, obtaining the experimental activities of 238 U and 232 Th using indirect gamma measures. The obtained findings show that the ratio Th/U varied from 0.11 to 1.33, with an average of 0.69. (author)

  17. Rates of carbonate soil evolution from carbon, U- and Th-series isotope studies: Example of the Astian sands (SE France)

    Science.gov (United States)

    Barbecot, Florent; Ghaleb, Bassam; Hillaire-Marcel, Claude

    2015-04-01

    In carbonate rich soils, C-isotopes (14C, 13C) and carbonate mass budget may inform on centennial to millennial time scale dissolution/precipitation processes and weathering rates, whereas disequilibria between in the U- and Th-decay series provide tools to document high- (228Ra-228Th-210Pb) to low- (234U, 230Th, 231Pa, 226Ra) geochemical processes rate, covering annual to ~ 1Ma time scales, governing both carbonate and silicate soil fractions. Because lithology constitutes a boundary condition, we intend to illustrate the behavior of such isotopes in soils developed over Astian sands formation (up to ~ 30% carbonate) from the Béziers area (SE France). A >20 m thick unsaturated zone was sampled firstly along a naturally exposed section, then in a cored sequence. Geochemical and mineralogical analyses, including stable isotopes and 14C-measurements, were complemented with 228U, 234U, 230Th, 226Ra, 210Pb and 228Th, 232Th measurements. Whereas the upper 7 m depict geochemical and isotopic features forced by dissolution/precipitation processes leading to variable radioactive disequilibria, but overall deficits in more soluble elements of the decay series, the lower part of the sequence shows strong excesses in 234U and 230Th over parent isotopes (i.e., 238U and 234U, respectively). These features might have been interpreted as the result of successive phases of U-loss and gains. However, 226Ra and 230Th are in near-equilibrium, thus leading to conclude at a more likely slow enrichment process in both 234Th(234U) and 230Th, which we link to dissolved U-decay during groundwater recharge events. In addition, 210Pb deficits (vs parent 226Ra) are observed down to 12 m along the natural outcropping section and below the top-soil 210Pb-excess in the cored sequence, due to gaseous 222Rn-diffusion over the cliff outcrop. Based on C-isotope and chemical analysis, reaction rates at 14C-time scale are distinct from those estimates at the short- or long-lived U-series isotopes

  18. Photofission of 232Th

    International Nuclear Information System (INIS)

    Arruda Neto, J.D.T.; Rigolon, W.; Herdade, S.B.; Riette, H.L.

    1983-11-01

    The bremsstrahlung-induced fission cross section of 232 Th was measured in the energy region of the Giant Dipole Resonance. The data analysis, performed in terms of the bremsstrahlung spectrum calculated in the Davies-Bethe-Maximon approximation, suggested that the photofission cross section measured at Livermore is correct, and that the (γ,f) data from Saclay are highly questionable. (Author) [pt

  19. 232Th, a rigid rotor

    International Nuclear Information System (INIS)

    Singh, M.; Pradeep Kumar; Singh, Y.; Varshney, A.K.; Gupta, D.K.

    2014-01-01

    We undertake the present work to treat 232 Th 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

  20. Measurement of Fission Fragment Angular Distributions for 14 N+ 232 Th and 11 B+ 235 U at Near-Barrier Energies

    International Nuclear Information System (INIS)

    Behera, B.R.; Jena, S.; Satapathy, M.; Ison, V.V.; Kailas, S.; Chatterjee, A.; Shrivastava, A.; Mahata, K.; Satpathy, L.; Basu, P.; Roy, S.; Sharan, M.; Chatterjee, M.L; Datta, S.K.

    2000-01-01

    Fission fragment angular distributions of heavy-ion induced fission in actinide nuclei at near-barrier energies show anomalous fragment anisotropies. At above barrier energies entrance channel dependence is a probable cause and explanation in terms of pre-equilibrium fission and the critical mass asymmetry parameter (Businaro-Gallone) has been tried. Target deformation and ground state spin also seem to influence the measured anisotropy. To understand the extent of importance of some or all of these features, we performed a set of experiments where (i) entrance channel dependence (ii) mass asymmetry on the two sides of Businaro-Gallone and (iii) different ground state spins are present. The channels chosen are 14 N+ 232 Th and 11 B+ 235 U. Experiments were done using the Pelletron accelerators at NSC, New Delhi and BARC-TIFR, Bombay. Compound nucleus populated in both cases is 246 Bk. 232 Th has ground state spin zero and 235 U has spin 7/2. Fragment anisotropies have been measured from 10-15 % above barrier to 10 % below barrier at similar excitation energy (around 40 MeV to 58 MeV). The mean square angular momentum is matched at least at one energy. Results indicate that when both excitation energy and angular momentum are matched, there are differences in the measured values of fission anisotropies. This implies entrance channel dependence consistent with the expectation of pre-equilibrium fission model. (authors)

  1. Sequential determination of U and Th isotopes, 226Ra, 228Ra, 210Pb, and 210Po in mushroom

    International Nuclear Information System (INIS)

    Rosa, Mychelle M.L.; Taddei, Maria Helena T.; Dias, Fabiana F.; Maihara, Vera A.

    2009-01-01

    For this study, mushroom samples were collected in Brazil at the Sao Paulo Metropolitan Region and at the Pocos de Caldas Plateau (PC; a region of elevated natural radioactivity, which houses the first Brazilian uranium mine). This paper discusses a sequential methodology to determine natural series radionuclides in mushrooms, such as uranium ( 238 U and 234 U) and thorium ( 232 Th, 230 Th, and 228 Th) isotopes, radium-226, radium-228, as well as lead-210 and polonium-210; using Alpha Spectrometry, Gamma Spectrometry, and Total Alpha and Beta Counting. The method involves total sample dissolution in a closed system in order to avoid loss of Polonium and employment of specific chromatographic resins for radionuclide purification. A subsequent interpretation of the results can provide information on pollutants present in mushrooms and infer possible contamination in the areas sampled as well as allow an association of measured concentrations to radioactive anomalies in the Plateau. (author)

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

    International Nuclear Information System (INIS)

    Taylor, L. L.; Loo, H. H.

    1999-01-01

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

  3. 230,232Th in milk, meat, and grain in Korea

    International Nuclear Information System (INIS)

    Lin, Xiujing; Choi, Minseok; Kim, Wan; Kang, Heedong; Doh, Sihhong; Kim, Dosung; Kim, Changkyu

    2004-01-01

    The concentrations of natural radioisotopes 230 Th and 232 Th 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 230 Th 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 232 Th 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 230 Th and 232 Th 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 230 Th and 232 Th in the rice was about 0.043 μSv/yr and highest because rice is the staple food of Koreans. (author)

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

    International Nuclear Information System (INIS)

    Lapa, Flavia Valverde

    2013-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-15

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

  6. Emanation of 232U and its radioactive daughter products from respirable size particles

    International Nuclear Information System (INIS)

    Cuddihy, R.G.; Griffith, W.C.; Hoover, M.D.; Kanapilly, G.M.; Stalnaker, N.D.

    1978-01-01

    This study is to develop a model for the emanation of 232 U and its radioactive daughter products from particles of Th-U fuel material. The radiation doses to internal organs following inhalation of these particles can only be calculated by knowing the rate of emanation of the daughters from particles in the lung and the subsequent excretion or translocation of the daughters to other organs. The emanation mechanisms are recoil of the daughter nuclei from the particle during alpha decay of the parent, diffusion of inert gas daughters from the particle and dissolution of the particle itself in biological fluids. Experiments to evaluate these mechanisms will involve ThO 2 and UO 2 particles in the size range 0.1 to 1.0 μm MMAD uniformly labeled with 232 U. The influence of the material temperature history on emanation will be investigated by heat treating particles at 600 and 1400 0 C

  7. Reduction of the dimensionality and comparative analysis of multivariate radiological data

    International Nuclear Information System (INIS)

    Seddeek, M.K.; Kozae, A.M.; Sharshar, T.; Badran, H.M.

    2009-01-01

    Computational methods were used to reduce the dimensionality and to find clusters of multivariate data. The variables were the natural radioactivity contents and the texture characteristics of sand samples. The application of discriminate analysis revealed that samples with high negative values of the former score have the highest contamination with black sand. Principal component analysis (PCA) revealed that radioactivity concentrations alone are sufficient for the classification. Rough set analysis (RSA) showed that the concentration of 238 U, 226 Ra or 232 Th, combined with the concentration of 40 K, can specify the clusters and characteristics of the sand. Both PCA and RSA show that 238 U, 226 Ra and 232 Th behave similarly. RSA revealed that one or two of them can be omitted without degrading predictions.

  8. Calibration of 232U solution; Calibracion de una disolucion de 232U

    Energy Technology Data Exchange (ETDEWEB)

    Galan Valera, M P; Acena Berrenechea, M L

    1988-07-01

    A method for as certain the activity by alpha spectroscopy with semiconductor detectors, of a solution of 232U is presented. It consists of the comparison with a 233U solution activity previously measured in a gridded ionization chamber of 2{pi} geometry. The total measurement uncertainty is about + - 0,02. (Author) 9 refs.

  9. U-series dating using thermal ionisation mass spectrometry (TIMS)

    International Nuclear Information System (INIS)

    McCulloch, M.T.

    1999-01-01

    U-series dating is based on the decay of the two long-lived isotopes 238 U(τ 1/2 =4.47 x 10 9 years) and 235 U (τ 1/2 0.7 x 10 9 years). 238 U and its intermediate daughter isotopes 234 U (τ 1/2 = 245.4 ka) and 230 Th (τ 1/2 = 75.4 ka) have been the main focus of recently developed mass spectrometric techniques (Edwards et al., 1987) while the other less frequently used decay chain is based on the decay 235 U to 231 Pa (τ 1/2 = 32.8 ka). Both the 238 U and 235 U decay chains terminate at the stable isotopes 206 Pb and 207 Pb respectively. Thermal ionization mass spectrometry (TIMS) has a number of inherent advantages, mainly the ability to measure isotopic ratios at high precision on relatively small samples. In spite of these now obvious advantages, it is only since the mid-1980's when Chen et al., (1986) made the first precise measurements of 234 U and 232 Th in seawater followed by Edwards et al., (1987) who made combined 234 U- 230 Th measurements, was the full potential of mass spectrometric methods first realised. Several examples are given to illustrate various aspects of TIMS U-series

  10. 232Th(d,4n)230Pa cross-section measurements at ARRONAX facility

    International Nuclear Information System (INIS)

    Duchemin, C.; Guertin, A.; Metivier, V.; Haddad, F.

    2015-01-01

    Full text of publication follows. The ARRONAX cyclotron [Ref.1], acronym for 'Accelerator for Research in Radiochemistry and Oncology at Nantes Atlantique' is a new facility installed in Nantes, France. A dedicated program has been launched on production of innovative radionuclides for PET imaging and for β- and α- targeted radiotherapy using proton or α particle. Since the accelerator is also able to deliver deuteron beams up to 35 MeV, we have reconsidered the possibility to use them to produce medical isotopes. In this study, we have focused on cross section measurements using the stacked-foil technique [Ref. 2] of one isotope dedicated to alpha radio-immunotherapy (α RIT) [Ref.3], 226 Th which can be produced through different routes. It's of great interest since it has been found to be a more potent alpha particle emitter for leukemia therapies than Bi 213 [Ref.4]. Indeed, the 226 Th decay produced a cascade of four α particles with a cumulated energy of 27.7 MeV. An additional interest is the possible use of a radionuclide generator system 230 U/ 226 Th. 230 U could be produced directly via 231 Pa(p, 2n) 230 U, and indirectly via 230 Pa using proton or deuteron beams through 232 Th(p, 3n) 230 Pa → 230 U, 232 Th(d, 4n) 230 Pa → 230 U. Twelve data sets are published concerning the 230 Pa cross section induced by proton [Ref 5], only one by deuteron [Ref.6]. As sometimes deuteron induced reaction gives higher cross section values, it seems interesting to focus our study on their use as projectile on 232 Th target to produce 230 Pa. Contaminants created during irradiation are also measured since a good optimization of the process is supposed to find the best compromise between production yield and purity of the final product. Our new sets of data are compared with the existing data [Refs.5,6] on other existing production routes and with results given by TALYS code calculations [Ref.7]. References: 1] F. Haddad and al., Eur. J. Med. Mol

  11. Response of gadolinium doped liquid scintillator to charged particles: measurement based on intrinsic U/Th contamination

    Science.gov (United States)

    Du, Q.; Lin, S. T.; He, H. T.; Liu, S. K.; Tang, C. J.; Wang, L.; Wong, H. T.; Xing, H. Y.; Yue, Q.; Zhu, J. J.

    2018-04-01

    A measurement is reported for the response to charged particles of a liquid scintillator named EJ-335 doped with 0.5% gadolinium by weight. This liquid scintillator was used as the detection medium in a neutron detector. The measurement is based on the in-situ α-particles from the intrinsic Uranium and Thorium contamination in the scintillator. The β–α and the α–α cascade decays from the U/Th decay chains were used to select α-particles. The contamination levels of U/Th were consequently measured to be (5.54±0.15)× 10‑11 g/g, (1.45±0.01)× 10‑10 g/g and (1.07±0.01)× 10‑11 g/g for 232Th, 238U and 235U, respectively, assuming secular equilibrium. The stopping power of α-particles in the liquid scintillator was simulated by the TRIM software. Then the Birks constant, kB, of the scintillator for α-particles was determined to be (7.28±0.23) mg/(cm2ṡMeV) by Birks' formulation. The response for protons is also presented assuming the kB constant is the same as for α-particles.

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

    International Nuclear Information System (INIS)

    Baker, V.C.; Marable, J.H.

    1980-02-01

    Results of resonance integral calculations for UO 2 and ThO 2 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 H 2 O 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 UO 2 resonance integrals calculated were in exceptionally good agreement with experimental values based on isolated rods. The ThO 2 results were approximately 6% lower than experimental values, and efforts to understand the discrepancy are discussed. 8 figures, 7 tables

  13. Measurement of the neutron-induced fission cross section of 232Th relative to 235U from 0.7 to 30 MeV

    International Nuclear Information System (INIS)

    Behzens, T.W.; Ables, E.; Browne, T.C.

    1982-01-01

    The authors have measured the fission cross-section ratio 232 Th: 235 U as a function of neutron energy from 0.7 to 30 MeV using ionization fission chambers, the threshold cross-section method, and the time-of-flight technique at the Lawrence Livermore National Laboratory 100-MeV electron linear accelerator. The measured cross-section ratio, averaged over the neutron energy interval from 1.75 to 4.00 MeV, was 0.1086 + 0.0024

  14. Distribution of activity concentrations of "2"3"8U and "2"3"2Th in soil samples from Minas Gerais state

    International Nuclear Information System (INIS)

    Peixoto, C.M.; Rodrigues, P.C.H.; Carvalho Filho, C.A.; Feliciano, V.M.D.; Fernandes, P.R.M.

    2016-01-01

    Soil contamination by radionuclides, heavy metal, pesticides, among others, threatens ecosystems and human health. Environmental monitoring bodies and agencies need reference values for these contaminants in order to assess the impacts of anthropogenic activities on soil contamination. Quality Reference Values (QRVs) reflect the natural concentrations of contaminants in soils without anthropic interference and must be regionally established. The aim of this study was the determination of natural concentrations and quality reference values for U and Th in soils from Minas Gerais State, Brazil. A large variation of the natural activity concentration of these radionuclides in soil was observed. The QRV for U was 86.5 Bq kg"-"1 and 90.81 Bq kg"-"1 for Th. Statistical analysis showed that the two elements have a positive correlation with the clay and organic matter content in soil, and with the soil orders Ultisol and Inceptisol. Uranium shows a strong correlation with As, Sb, Se and Hg, while Thorium does not show correlation with any of the trace elements. (author)

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

    Science.gov (United States)

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

    2014-09-01

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

  16. Production of 232,233Pa in 6Li+232Th Collisions in the Classical Trajectory Approach

    International Nuclear Information System (INIS)

    Aleshin, V.P.

    2000-01-01

    The semiclassical model of nuclear reactions with loosely bound projectiles (V.P. Aleshin, B.I. Sidorenko, Acta Phys. Pol. B29, 325 (1998)) is refined and compared with experimental data of Rama Rao et al. on the excitation function for the production of 232,233 Pa in 6 Li+ 232 Th collisions at E = 30-50 MeV. The main contribution to the production of 232 Pa is the 2 neutron emission from excited states of 234 Pa formed in the ( 6 Li,α) reaction. The main source of 233 Pa is the ( 6 Li,αp) reaction followed by γ transitions from excited states of 233 Th to 233 Th (g.s.) which transforms to 233 Pa through β - decay. The ground state of 6 Li regarded as a combination of n+p+α is modeled with the K=2, l x =l y =0 hyperspherical function. The calculation underpredicts the excitation function of 232 Pa by a factor of 0.6 and overpredicts the excitation function of 233 Pa by a factor of 2.3, on the average. With the more realistic wave function of 6 Li both factors are expected to be closer to 1. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

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

  18. Fission Evaluation on Th-232

    International Nuclear Information System (INIS)

    Lee, Yong-Deok; Lee, Young-Ouk; Park, Joo-Hwan

    2007-01-01

    In recent years, several studies of neutron induced reaction on thorium were carried out in the framework of an IAEA coordinate research project involving a US contribution. The importance of Th-232 is for an innovative fuel cycle concept based on thorium fuel. Thorium fuels are also considered in accelerator driven system (ADS) to produce the power and radioactive waste transmutation. Therefore, the accurate neutron cross section for fission is crucially important for the design of various reactor systems. On December 2006, the ENDF/B-VII involving the new evaluation of actinides for Th-U fuel cycle was released. From the current environmental change, increasing oil price, air pollution by carbon dioxide, drain of oil resource, increasing demand of electricity, and energy independence, nuclear power is slowly to start to be reconsidered recently and it might be an alternative proposal as a production facility of energy and a reuse of resources. Even though it produces the nuclear wastes, it has an advantage in the emission of greenhouse gases. Therefore, new concept of nuclear technology to be developed for power production is subject to the condition of increased safety, reduction of nuclear wastes, resistance to nuclear material proliferation, Thorium fuel cycle is the most feasible option to satisfy the condition. Specially, thorium reserves are much larger than those of uranium

  19. Estimation of internal radiation dose to the adult Asian population from the dietary intakes of two long-lived radionuclides

    International Nuclear Information System (INIS)

    Iyengar, G.V.; Kawamura, H.; Dang, H.S.; Parr, R.M.; Wang, J.W.; Akhter, Perveen; Cho, S.Y.; Natera, E.; Miah, F.K.; Nguyen, M.S.

    2004-01-01

    Daily dietary intakes of two naturally occurring long-lived radionuclides, 232 Th and 238 U, were estimated for the adult population living in a number of Asian countries, using highly sensitive analytical methods such as instrumental and radiochemical neutron activation analysis (INAA and RNAA), and inductively coupled plasma mass spectrometry (ICP-MS). The Asian countries that participated in the study were Bangladesh (BGD), China (CPR), India (IND), Japan (JPN), Pakistan (PAK), Philippines (PHI), Republic of Korea (ROK) and Vietnam (VIE). Altogether, these countries represent more than 50% of the world population. The median daily intakes of 232 Th ranged between 0.6 and 14.4 mBq, the lowest being for Philippines and the highest for Bangladesh, and daily intakes of 238 U ranged between 6.7 and 62.5 mBq, lowest and the highest being for India and China, respectively. The Asian median intakes were obtained as 4.2 mBq for 232 Th and 12.7 mBq for 238 U. Although the Asian intakes were lower than intakes of 12.3 mBq (3.0 μg) 232 Th and 23.6 mBq (1.9 μg) 238 U proposed by the International Commission on Radiological Protection (ICRP) for the ICRP Reference Man, they were comparable to the global intake values of 4.6 mBq 232 Th and 15.6 mBq 238 U proposed by the United Nation Scientific Commission on Effects of Radiation (UNSCEAR). The annual committed effective doses to Asian population from the dietary intake of 232 Th and 238 U were calculated to be 0.34 and 0.20 μSv, respectively, which are three orders of magnitude lower than the global average annual radiation dose of 2400 μSv to man from the natural radiation sources as proposed by UNSCEAR

  20. Determination of uranium concentrations and "2"3"4U/"2"3"8U activity ratio in some granitic rock samples by alpha spectrometry: application of a radiochemical procedure

    International Nuclear Information System (INIS)

    Khattab, Mahmoud R.

    2016-01-01

    The present study is an application of a radiochemical procedure using alpha spectrometry technique for determination of uranium isotopes "2"3"8U, "2"3"4U and "2"3"5U on 13 granitic samples. These samples were collected from Gabal Gattar area, Northeastern Desert, Egypt. The collected samples were digested using microwave technique with aqua regia and spiked with "2"3"2U for chemical yield and activity calculation. Separation of uranium isotopes from the samples was done by Dowex 1 x 4 (50-100 mesh) resin followed by source preparation using microprecipitation technique. The concentrations of "2"3"8U were ranged between 28.9±0.9 and 134.8±1.8 Bq/g, and the "2"3"4U concentrations were between 24±0.6 and 147.7±2.2 Bq/g. For the "2"3"5U, the activity concentrations were between 1.3±0.2 and 6.7±1.2 Bq/g. The activity ratio of "2"3"4U/"2"3"8U was calculated and varied from 0.80 to 1.30. (author)

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

    International Nuclear Information System (INIS)

    Lovrencic, I.; Orescanin, V.; Barisic, D.; Mikelic, L.; Rozmaric Macefat, M.; Lulic, St.; Pavlovic, G.

    2006-01-01

    The 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)

  2. 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)

  3. Computer simulation of the natural U 238 and U 235 radioactive series decay

    International Nuclear Information System (INIS)

    Barna, A.; Oncescu, M.

    1980-01-01

    The principles of the computer simulation of a radionuclide decay - its decay scheme adoption and codification -, and the adoption principle of a radionuclide chain in a series are applied to the natural U 238 and U 235 series radionuclide decay computer simulation. Using the computer simulation data of these two series adopted chains, the decay characteristic quantities of the series radionuclides, the gamma spectra and the basic characteristics of each of these series are determined and compared with the experimental values given in the literature. (author)

  4. Comment on "Zircon U-Th-Pb dating using LA-ICP-MS: Simultaneous U-Pb and U-Th dating on 0.1 Ma Toya Tephra, Japan" by Hisatoshi Ito

    Science.gov (United States)

    Guillong, M.; Schmitt, A. K.; Bachmann, O.

    2015-04-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) of eight zircon reference materials and synthetic zircon-hafnon end-members indicate that corrections for abundance sensitivity and molecular zirconium sesquioxide ions (Zr2O3+) are critical for reliable determination of 230Th abundances in zircon. Other polyatomic interferences in the mass range 223-233 amu are insignificant. When corrected for abundance sensitivity and interferences, activity ratios of (230Th)/(238U) for the zircon reference materials we used average 1.001 ± 0.010 (1σ error; mean square of weighted deviates MSWD = 1.45; n = 8). This includes the 91500 and Plešovice zircons, which were deemed unsuitable for calibration of (230Th)/(238U) by Ito (2014). Uranium series zircon ages generated by LA-ICP-MS without mitigating (e.g., by high mass resolution) or correcting for abundance sensitivity and molecular interferences on 230Th such as those presented by Ito (2014) are potentially unreliable.

  5. U-Th series nuclides in the Gulf of Mexico

    International Nuclear Information System (INIS)

    Scott, M.R.

    1981-01-01

    A study of U and Th series nuclides is being conducted on sediments from the Gulf of Mexico. Uranium concentrations as a function of depth have been determined, as well as changes in the 234 U/ 238 U activity ratio. The geochemical behavior of uranium in shelf sediments is discussed

  6. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    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 ...

  7. 238U content in soils of Byelorussia

    International Nuclear Information System (INIS)

    Shagalova, Eh.D.

    1986-01-01

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

  8. Neutron scattering studies in the actinide region

    International Nuclear Information System (INIS)

    Beghian, L.E.; Kegel, G.H.R.

    1991-08-01

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

  9. Determination of 228Th, 230Th, and 232Th in environmental samples from uranium mining and milling operations

    International Nuclear Information System (INIS)

    Durham, R.W.; Joshi, S.R.

    1979-01-01

    A method is described for the determination of 228 Th, 230 Th, and 232 Th in environmental samples from uranium mining and milling operations. The analytical procedure is based on the direct determination of 228 Th in the sample by high resolution γ-spectrometry followed by extraction and purification of the thorium fraction using high molecular weight amines and an anion-exchange technique, respectively, prior to α-spectrometry to determine isotopic ratios. The lowest level of detection for each thorium isotope is 0.01 pCi/g for solid samples and 20 pCi/l for aqueous samples. Replicate analyses of a typical mine waste stream gave a standard deviation of +-3% for 228 Th. Standard deviations of the 230 Th and 232 Th increased to +-11% apparently due to traces of 210 Po interfering in the α-spectrometry. (author)

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  11. Quantifying K, U and Th contents of marine sediments using shipboard natural gamma radiation spectra measured on DV JOIDES Resolution

    Science.gov (United States)

    De Vleeschouwer, David; Dunlea, Ann G.; Auer, Gerald; Anderson, Chloe H.; Brumsack, Hans; de Loach, Aaron; Gurnis, Michael C.; Huh, Youngsook; Ishiwa, Takeshige; Jang, Kwangchul; Kominz, Michelle A.; März, Christian; Schnetger, Bernhard; Murray, Richard W.; Pälike, Heiko; Expedition 356 shipboard scientists, IODP

    2017-04-01

    During International Ocean Discovery Program (IODP) expeditions, shipboard-generated data provide the first insights into the cored sequences. The natural gamma radiation (NGR) of the recovered material, for example, is routinely measured on the ocean drilling research vessel DV JOIDES Resolution. At present, only total NGR counts are readily available as shipboard data, although full NGR spectra (counts as a function of gamma-ray energy level) are produced and archived. These spectra contain unexploited information, as one can estimate the sedimentary contents of potassium (K), thorium (Th), and uranium (U) from the characteristic gamma-ray energies of isotopes in the 40K, 232Th, and 238U radioactive decay series. Dunlea et al. [2013] quantified K, Th and U contents in sediment from the South Pacific Gyre by integrating counts over specific energy levels of the NGR spectrum. However, the algorithm used in their study is unavailable to the wider scientific community due to commercial proprietary reasons. Here, we present a new MATLAB algorithm for the quantification of NGR spectra that is transparent and accessible to future NGR users. We demonstrate the algorithm's performance by comparing its results to shore-based inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasma-emission spectrometry (ICP-ES), and quantitative wavelength-dispersive X-ray fluorescence (XRF) analyses. Samples for these comparisons come from eleven sites (U1341, U1343, U1366-U1369, U1414, U1428-U1430, U1463) cored in two oceans during five expeditions. In short, our algorithm rapidly produces detailed high-quality information on sediment properties during IODP expeditions at no extra cost. Dunlea, A. G., R. W. Murray, R. N. Harris, M. A. Vasiliev, H. Evans, A. J. Spivack, and S. D'Hondt (2013), Assessment and use of NGR instrumentation on the JOIDES Resolution to quantify U, Th, and K concentrations in marine sediment, Scientific Drilling, 15, 57-63.

  12. U/Th-isotopes as natural analogues for the mobility of actinides in granitic rocks

    International Nuclear Information System (INIS)

    Mengel, K.; Gerdes, A.

    2001-01-01

    The short-lived decay products of 238 U ( 234 U and 230 Th) can be used as natural analogues for actinides in a hard rock repository. Their mobility in the past may serve as a key for understanding actinide migration in the future. For generally old calcites of the HRL Aespoethe age of disturbance of 238 U/ 234 U and 234 U/ 230 Th activity ratios ranges from 30 000 to 436 000 years at degrees of disturbance ranging from 0.5 to 6.7. The results obtained imply that during the past 440 000 years U was mobile throughout the tunnel sections of the HRL Aespoeinvestigated here. For the FL Grimsel, the disequilibrium states of the 234 U/ 238 U and 230 Th/ 234 U activity ratios in fracture minerals (calcites silicates) also imply that the reactions causing isotopic disturbances have occurred within the past 500 000 years. The U/Th-isotope data of both the samples from the HRL Aespoeand the FL Grimsel have in common the mobilization of U in secondary fracture minerals by migrating solutions within the past 500 000 years. As for the question of a final disposal of radioactive waste in granite host rocks, the transport of U - and thus of similarly behaving actinides - in migrating underground solutions can therefore not be ruled out, if suitable hydraulic systems are considered. (orig.)

  13. Environmental Characterization and Radioecological Assessment of Suez Canal Area, Egypt

    International Nuclear Information System (INIS)

    Ramadan, A.A.; Zaki, A.H.; Diab, M.; Al-Ashry, KH.A.M.

    2015-01-01

    The present study was conducted to investigate the environmental characteristic and radioecological assessment of the Suez Canal area, Egypt. The hydrochemical parameters including major elements (Ca, Mg, Na, Cl, SO 4 , HCO 3 ) and trace elements (Zn, Pb, Fe, Cu, Cd) of the soil, plant and water samples collected from the Suez Canal area were measured. The natural radioactivity and man-made radionuclides were measured in the same samples.The specific activities of 238 U series, 232 Th series, 40 K and 137 Cs (Bq/kg dry weight) were measured using gamma ray spectrometers based on hyper pure germanium detectors. The absorbed radiation dose rates in air (nGy/h) due to natural radionuclides in soil, and radium equivalent activity index (Bq/kg) were calculated. The average specific activity of 238 U series, 232 Th series and 40 K in soil samples were 12.9, 10.2 and 144.9 Bq/kg, respectively. The activity concentrations of 137 Cs in the different collected samples and 238 U and 232 Th series in plant and water samples were less than the lower detection limit. The average specific activity of 40 K in plant samples was 325.8 Bq/kg. The concentration and distribution pattern of 238 U series in soil can be used to trace the radiological impact of the non-nuclear industries on the Suez Canal area.

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

    International Nuclear Information System (INIS)

    Russ III, G.P.

    1997-01-01

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

  15. 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...

  16. Dynamic effects in neutron induced fission of 230Th and 232Th

    International Nuclear Information System (INIS)

    Trochon, J.; Frehaut, J.; Pranal, Y.; Simon, G.; Boldeman, J.W.

    1982-09-01

    The fission fragment characteristics of the two thorium isotopes 230 Th and 232 Th have been measured in an attempt to study the evolution of the fissioning nucleus from saddle point to scission. The partial fission channel at the saddle point have been deduced from a fission fragment angular distribution and fission cross section analysis. Changes with energy in the average number of prompt neutron (νsub(p)) emitted per fission and the total fragment kinetic energy (TKE) have been observed in the fission threshold region. A rather good fit of νsub(p) and TKE values has been obtained on the basis of a correlation of these quantities and the partial fission channel ratios. This leads to expect for these isotopes a passage from saddle point to scission sufficiently rapid for the coupling between collective and intrinsic excitation to be very weak [fr

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  18. A multielement analysis of natural radionuclides in an area of Pernambuco - Brazil

    International Nuclear Information System (INIS)

    Santos Junior, Jose Araujo dos; Menezes, Romulo Simoes Cezar

    2007-01-01

    Levels of natural radioactivity are the major cause of external exposure to gamma radiation. Based on this parameter, natural radioactivity of 238 U, 232 Th and 40 K were evaluated in a semiarid region of Pernambuco, Brazil, with the aim of obtaining radiometric monitoring of agricultural soils. For the analyses, the gamma spectrometry was utilized with a hyperpure germanium detector with an intrinsic efficiency of 27.7%. Seventy eight samples of soil that were collected in an area of approximately 55,500 m 2 , around an anomaly of uranium in rock, were analyzed. The activities of 238 U were evaluated by the 63 keV photopeak of 234 Th, that of 232 Th by the 338, 911 and 969 keV peak of 228 Ac, and that of 40 K by its 1,461 keV peak. The mean of the activities for these radionuclides were 91 Bq.kg -1 (median 88 Bq.kg -1 ) for the 238 U, 228 Bq.kg -1 (median 215 Bq.kg -1 ) for the 232 Th and 1,827 Bq.kg -1 (median 1,662 Bq.kg -1 ) for the 40 K. The anomalous rock did not present neither associated thorium nor potassium (values below the limit of detection: -1 of 232 Th and - '1 of 40 K), thus giving the characteristic of another natural radioactivity source. The obtained data allow to take important conclusions about the distribution of the radioactivity levels, to establish radioecological parameters. (author)

  19. Direct gamma-ray measurement of different radionuclides in the surface water of Suez Canal

    International Nuclear Information System (INIS)

    Lasheen, Y.F.; El-Zakla, T.; Seliman, A.F.; Abdel-Rassoul, A.A.

    2008-01-01

    The radioactivity levels of naturally-occurring 238 U, 232 Th, 226 Ra and 40 K and anthropogenic 137 Cs in surface water from eight locations in the Suez Canal have been assessed by gamma-ray spectrometry. The samples were further characterized by determination of the common cations and anions using ion chromatography. A comparison of 137 Cs radioactivity levels in surface water from the Suez Canal with those of other sea waters is presented. The radioactivity levels of 238 U, 232 Th, 226 Ra and 40 K from sea water are also reported. The effect of total dissolved solids (T.D.S.), chloride, sulphate ion concentrations on the radioactivity levels of 238 U, 232 Th and 226 Ra is discussed. (authors)

  20. Multilevel effect in uranium-238 and thorium-232 effective neutron capture resonance integrals

    International Nuclear Information System (INIS)

    Tellier, H.

    1981-01-01

    Until now, there has been a discrepancy between the computed and the measured values of the /sup 238/U effective capture integral. Recently, several new measurements of the resonance parameters were carried out and the use of a multilevel formalism was suggested to compute the /sup 238/U cross sections. This paper shows that the simultaneous use of recent parameters and the Reich-Moore formalism explain the discrepancy. 31 refs

  1. Uranium Age Determination by Measuring the 230Th / 234U Ratio

    International Nuclear Information System (INIS)

    LAMONT, STEPHEN P.

    2004-01-01

    A radiochemical isotope dilution mass spectrometry method has been developed to determine the age of uranium materials. The amount of 230Th activity, the first progeny of 234U, that had grown into a small uranium metal sample was used to determine the elapsed time since the material was last radiochemically purified. To preserve the sample, only a small amount of oxidized uranium was removed from the surface of the sample and dissolved. Aliquots of the dissolved sample were spiked with 233U tracer and radiochemically purified by anion-exchange chromatography. The 234U isotopic concentration was then determined by thermal ionization mass spectrometry. Additional aliquots of the sample were spiked with 229Th tracer, and the thorium was purified using two sequential anion-exchange chromatography separations. The isotopic concentrations of 230Th and 232Th were determined by TIMS. The lack of any 232Th confirmed the assumption that all thorium was removed from the uranium sample at the time of purification. The 230Th and 234U mass concentrations were converted to activities and the 230Th/234U ratio for the sample was calculated. The experimental 230Th/234U ratio showed the uranium in this sample was radiochemically purified in about 1945. Isotope dilution thermal ionization mass spectrometry has sufficient sensitivity to determine the age of 100 samples of uranium. This method could certainly be employed as a nuclear forensic method to determine the age of small quantities of uranium metal or salts. Accurate determination of the ultra-trace 230Th radiochemically separated from the uranium is possible due to the use of 229Th as an isotope dilution tracer. The precision in the experimental age of the uranium could be improved by making additional replicate measurements of the 230Th/234U isotopic ratio or using a larger initial sample

  2. Studies on use of reflector material and its position within FBR core for reducing U{sup 232} content of U produced in ThO{sub 2} radial blankets

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Sujoy, E-mail: sujoy@igcar.gov.in [Core Design Group, IGCAR, Kalpakkam (India); Prasad, Rajeev Ranjan; Bagchi, Subhrojit [Core Design Group, IGCAR, Kalpakkam (India); Mohanakrishnan, P. [MCNS, Manipal University, Manipal (India); Arul, A. John; Puthiyavinayagam, P. [Core Design Group, IGCAR, Kalpakkam (India)

    2015-11-15

    Highlights: • Nuclear data processing for multigroup neutron transport calculation. • Discrete ordinate and Monte Carlo neutron transport. • Breeding of Thorium in Fast Reactor. • Minimization of U{sup 232} in U{sup 233}. • Fuel burn up using Neutron Diffusion. - Abstract: Presence of U{sup 232} in U{sup 233} bred in thorium blanket of fast reactor is a major concern in fuel reprocessing. The former's daughter products being hard gamma emitter and the isotope itself having substantial half life, its presence beyond 10 ppm makes fuel recycle complicated and expensive. In this study possibility of decreasing U{sup 232} production in a typical FBR blanket by means of spectrum modification is examined. SS, depleted B{sub 4}C, SiC, Mo and W regions were introduced between core and radial blanket and evolution of isotopes were studied to arrive at an optimal configuration that satisfies requirements of breeding U{sup 233} and lowering U{sup 232}concentration. SS, B{sub 4}C, SiC, Mo and W are known to be high temperature material with appropriate stability in harsh fast reactor environment. Study has shown that introducing two SS reflector rows can achieve the required low value of U{sup 232}concentration without greatly compromising the U{sup 233}production.

  3. Determination of uranium and thorium activity concentrations using activation analysis in beach sands from extreme south Bahia, Brazil

    International Nuclear Information System (INIS)

    Vasconcelos, Danilo C.; Oliveira, Arno H.; Silva, Mario R.S.; Penna, Rodrigo; Santos, Talita O.; Pereira, Claubia; Rocha, Zildete; Menezes, Maria Angela B.C.

    2009-01-01

    Levels of natural radioactivity are the major cause of external exposure to gamma radiation. Thus, the determination of activity concentration of primordial radionuclides, such as 238 U and 232 Th, in soils, sand and rock is of basic importance to estimate the radiation levels to which man is directly or indirectly exposed. In order to study the process of specific activity of 238 U and 232 Th, beaches sands samples were collected from eight different locations in extreme south of Bahia state from Brazil. The samples have been analyzed by instrumental neutron activation analyses and for determination of thorium concentrations and delayed neutrons analysis for determination of uranium. The mean specific activity for 238 U and 232 Th was higher in Cumuruxatiba than in others locations studied. Alcobaca and Caraiva also presented high values. The concentrations of these radionuclides were compared with typical world values and Cumuruxatiba have specific activity higher than the others locations, 2,984 Bq/kg maximum value for 238 U and 1,8450 Bq/kg maximum value for 232 Th and activity concentrations in Cumuruxatiba are higher in black sand than in no black sand, suggesting presence of monazite.(author)

  4. Bioaccessibility of U, Th and Pb in particulate matter from an abandoned uranium mine

    Science.gov (United States)

    Millward, Geoffrey; Foulkes, Michael; Henderson, Sam; Blake, William

    2016-04-01

    Currently, there are approximately 150 uranium mines in Europe at various stages of either operation, development, decommissioning, restoration or abandonment (wise-uranium.com). The particulate matter comprising the mounds of waste rock and mill tailings poses a risk to human health through the inadvertent ingestion of particles contaminated with uranium and thorium, and their decay products, which exposes recipients to the dual toxicity of heavy elements and their radioactive emissions. We investigated the bioaccessibility of 238U, 232Th and 206,214,210Pb in particulate samples taken from a contaminated, abandoned uranium mine in South West England. Sampling included a mine shaft, dressing floor and waste heap, as well as soils from a field used for grazing. The contaminants were extracted using the in-vitro Unified Bioaccessibility Research Group of Europe Method (UBM) in order to mimic the digestion processes in the human stomach (STOM) and the combined stomach and gastrointestinal tract (STOM+INT). Analyses of concentrations of U, Th and Pb in the extracts were by ICP-MS and the activity concentrations of radionuclides were determined on the same particles, before and after extraction, using gamma spectroscopy. 'Total' concentrations of U, Th and Pb for all samples were in the range 57 to 16,200, 0.28 to 3.8 and 69 to 4750 mg kg-1, respectively. For U and Pb the concentrations in the STOM fraction were lower than the total and STOM+INT fractions were even lower. However, for Th the STOM+INT fractions were higher than the STOM due to the presence of Th carbonate species within the gastrointestinal fluid. Activity concentrations for 214Pb and 210Pb, including total, STOM and STOM+INT, were in the range 180 to samples were 39% and 8% in the STOM and STOM+INT, respectively, whereas the respective BAFs for 232Th were 3% and 9%. For stable 206Pb the STOM and STOM+INT BAFs were 16% and 3% for the most contaminated samples, whereas those from the field had 44% in the

  5. The Amster concept: a configuration generating its own uranium with a mixed thorium and uranium support

    International Nuclear Information System (INIS)

    Vergnes, J.; Garzenne, C.; Lecarpentier, D.; Mouney, H.; Delpech, M.

    2001-01-01

    AMSTER is a continuously reloaded, graphite-moderated molten salt critical reactor, using a 238 U or 232 Th fuel support, slightly enriched with 235 U if necessary. Using this concept, one can define a large number of configurations according to the products loaded and recycled. The choice of thorium fuel support leads to two configurations requiring no additional 235 U as fissile material: a configuration with one moderating zone, incinerating Transuranium elements (TRU); a configuration with 2 moderating zones self-consuming TRU and regenerating the fissile uranium ( 233 U). In this configuration, it is even possible to burn 238 U (from depleted uranium) by adding it to the thorium support. These configurations use a minimum amount of fuel (100 kg of 232 Th or 100 kg of a 232 Th- 238 U mix per TWh) and produce very little TRU (a few tens of grams per TWh). (author)

  6. Determination of the activity concentration of 230Th in phosphoric acids produced in Brazil

    International Nuclear Information System (INIS)

    Taddei, M.H.T.; Ferreira, M.T.; Fukuma, H.T.; Xavier, T.T.; Sousa, F.V.T.S.

    2017-01-01

    The high uranium phosphate rock from Itataia, Brazil, was processed using the wet route in the dihydrate system to manufacture phosphoric acid. The uranium contained in phosphoric acid was recovered by the solvent extraction technique. The distribution of the long half-life radionuclides from the decay series of 238 U and 232 Th were evaluated in these processes. The 26 Ra, 228 Ra and 210 Pb radionuclides were found predominantly in phosphogypsum, while the isotopes of 228 Th, 230 Th and 232 Th predominated in phosphoric acid after extracting uranium. The main concern in the commercialization of phosphoric acid that will be produced in the Itataia plant is in relation to the content of 230 Th. This work determined the content of these radionuclides in phosphoric acid from different locations in the country in order to compare

  7. Assessment of age-dependent radiation dose due to intake of uranium and thorium in drinking water from Sikar District, Rajasthan, India

    International Nuclear Information System (INIS)

    Duggal, Vikas; Rani, Asha; Balaram, V.

    2016-01-01

    The concentrations of 238 U and 232 Th have been determined in drinking water samples collected from the Sikar district of Rajasthan State, India. The samples have been analysed by using high-resolution inductively coupled plasma mass spectrometry. 238 U content in water samples ranged from 8.20 to 202.63 μg l -1 and 232 Th content ranged from 0.57 to 1.46 μg l -1 . The measured 238 U content in 25 % of the analysed samples exceeded the World Health Organization (WHO) and United States Environmental Protection Agency drinking water guidelines of 30 μg l -1 and 12.5 % of the samples exceeded the 60 μg l -1 Indian maximum acceptable concentration recommended by the Atomic Energy Regulatory Board, India. The annual effective doses (μSv y -1 ) due to ingestion of 238 U and 232 Th for different age groups were also calculated. The results compared with the recommended value reported by the WHO. (authors)

  8. Estimation of internal radiation dose to the adult Asian population from the dietary intakes of two long-lived radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Iyengar, G.V. E-mail: v.iyengar@iaea.org; Kawamura, H.; Dang, H.S.; Parr, R.M.; Wang, J.W.; Akhter, Perveen; Cho, S.Y.; Natera, E.; Miah, F.K.; Nguyen, M.S

    2004-07-01

    Daily dietary intakes of two naturally occurring long-lived radionuclides, {sup 232}Th and {sup 238}U, were estimated for the adult population living in a number of Asian countries, using highly sensitive analytical methods such as instrumental and radiochemical neutron activation analysis (INAA and RNAA), and inductively coupled plasma mass spectrometry (ICP-MS). The Asian countries that participated in the study were Bangladesh (BGD), China (CPR), India (IND), Japan (JPN), Pakistan (PAK), Philippines (PHI), Republic of Korea (ROK) and Vietnam (VIE). Altogether, these countries represent more than 50% of the world population. The median daily intakes of {sup 232}Th ranged between 0.6 and 14.4 mBq, the lowest being for Philippines and the highest for Bangladesh, and daily intakes of {sup 238}U ranged between 6.7 and 62.5 mBq, lowest and the highest being for India and China, respectively. The Asian median intakes were obtained as 4.2 mBq for {sup 232}Th and 12.7 mBq for {sup 238}U. Although the Asian intakes were lower than intakes of 12.3 mBq (3.0 {mu}g) {sup 232}Th and 23.6 mBq (1.9 {mu}g) {sup 238}U proposed by the International Commission on Radiological Protection (ICRP) for the ICRP Reference Man, they were comparable to the global intake values of 4.6 mBq {sup 232}Th and 15.6 mBq {sup 238}U proposed by the United Nation Scientific Commission on Effects of Radiation (UNSCEAR). The annual committed effective doses to Asian population from the dietary intake of {sup 232}Th and {sup 238}U were calculated to be 0.34 and 0.20 {mu}Sv, respectively, which are three orders of magnitude lower than the global average annual radiation dose of 2400 {mu}Sv to man from the natural radiation sources as proposed by UNSCEAR.

  9. U-series dating using thermal ionisation mass spectrometry (TIMS)

    Energy Technology Data Exchange (ETDEWEB)

    McCulloch, M.T. [Australian National University, Canberra, ACT (Australia). Research School of Earth Science

    1999-11-01

    U-series dating is based on the decay of the two long-lived isotopes{sup 238}U({tau}{sub 1/2}=4.47 x 10{sup 9} years) and {sup 235}U ({tau}{sub 1/2} 0.7 x 10{sup 9} years). {sup 238}U and its intermediate daughter isotopes {sup 234}U ({tau}{sub 1/2} = 245.4 ka) and {sup 230}Th ({tau}{sub 1/2} = 75.4 ka) have been the main focus of recently developed mass spectrometric techniques (Edwards et al., 1987) while the other less frequently used decay chain is based on the decay {sup 235}U to {sup 231}Pa ({tau}{sub 1/2} = 32.8 ka). Both the {sup 238}U and {sup 235}U decay chains terminate at the stable isotopes {sup 206}Pb and {sup 207}Pb respectively. Thermal ionization mass spectrometry (TIMS) has a number of inherent advantages, mainly the ability to measure isotopic ratios at high precision on relatively small samples. In spite of these now obvious advantages, it is only since the mid-1980`s when Chen et al., (1986) made the first precise measurements of {sup 234}U and {sup 232}Th in seawater followed by Edwards et al., (1987) who made combined {sup 234}U-{sup 230}Th measurements, was the full potential of mass spectrometric methods first realised. Several examples are given to illustrate various aspects of TIMS U-series 9 refs., 3 figs.

  10. Calibration of 232U solution

    International Nuclear Information System (INIS)

    Galan Valera, M. P.; Acena Berrenechea, M. L.

    1988-01-01

    A method for as certain the activity by alpha spectroscopy with semiconductor detectors, of a solution of 232U is presented. It consists of the comparison with a 233U solution activity previously measured in a gridded ionization chamber of 2π geometry. The total measurement uncertainty is about + - 0,02. (Author) 9 refs

  11. Chain and independent fission product yields adjusted to conform with physical conservation laws. Part 2

    International Nuclear Information System (INIS)

    Crouch, E.A.C.

    1976-01-01

    Previously reported adjustments to the chain yields and independent yields for the thermal neutron induced fission of 233 U, 235 U, 239 Pu and 241 Pu, the fast neutron induced fission of 232 Th, 233 U, 235 U, 238 U, 239 Pu, 240 Pu and 241 Pu, and the 14 MeV neutron induced fission of 232 Th, 233 U, 235 U and 238 U, have been recalculated using the principle of least squares. The adjustments to the chain yields so found are much smaller than those previously reported. (author)

  12. Measurement of the neutron capture cross-section of 232Th using the neutron activation technique

    International Nuclear Information System (INIS)

    Naik, H.; Singh, Sarbjit; Goswami, A.; Manchanda, V.K.; Prajapati, P.M.; Surayanarayana, S.V.; Nayak, B.K.; Sharma, S.C.; Jagadeesan, K.C.; Thakare, S.V.; Raj, D.; Ganesan, S.; Mulik, V.K.; Sivashankar, B.S.; Mukherjee, S.

    2011-01-01

    The 232 Th(n, γ) reaction cross-section at average neutron energies of 3.7±0.3 MeV and 9.85±0.38 MeV from the 7 Li(p, n) reaction has been determined for the first time using activation and off-line γ -ray spectrometric technique. The 232 Th(n, 2n) reaction cross-section at the average neutron energy of 9.85±0.38 MeV has been also determined using the same technique. The experimentally determined 232 Th(n, γ) and 232 Th(n, 2n) reaction cross-sections were compared with the evaluated data of ENDF/B-VII, JENDL-4.0 and JEFF-3.1 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 different reaction channels including fission. The 232 Th(n, γ) and 232 Th(n, 2n) reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were found to be slightly higher than the experimental data. (orig.)

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

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  15. Radioactivity of long-lived gamma emitters in some rice varieties in the Philippines

    International Nuclear Information System (INIS)

    Soriano, Jhon Cris N.

    2016-06-01

    This study measured the activity concentrations of Uranium-238 (U-238), Thorium-232 (Th-232), and Potassium-40 (K-40) in five of the widely consumed rice varieties in the Philippines using a NaI (Tl) scintillation detector. To determine the uptake of radionuclides of these varieties, the activity concentrations in soil were measured and the transfer factor was calculated. Results showed that the activity concentrations of rice ranged from Not Detected (ND) to 0.579 Bq/kg U-238, ND-1.575 BQ/kg for TH-232, and 44.66014526-106.0412811 Bq/kg for K-40. These values are lower than the activity concentration in soil (0.495-5.327 Bq/kg for U-238, 0.459-6.291 Bq/kg for Th-232, and 104.433-351.405 Bq/kg for K-40). These results show that the activity concentrations in the soil do not reflect the activity concentrations in rice. The transfer factors computed range from ND-1.021 for U-238, ND-0.384 for Th-232, 0.127090299- 0.926872575 for K-40. The Average Annual Committed Effective Doses (AACEDs) in this study were found to be lower than the worldwide average ingestion exposure (290 μSv) reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The results suggest that consumption of rice pose no radiological health risk to Filipinos. (author)

  16. Correlations of natural radionuclides in soil with those in sediment from the Danube and nearby irrigation channels

    International Nuclear Information System (INIS)

    Krmar, M.; Varga, E.; Slivka, J.

    2013-01-01

    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. -- Highlights: ► 238 U, 232 Th and 40 K 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 238 U, 232 Th and 40 K can be good indicator for TENORM monitoring

  17. Gamma-spectrometric determination of {sup 232}U in uranium-bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Zsigrai, Jozsef [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), 76125 Karlsruhe, P.O. Box 2340 (Germany); Nguyen, Tam Cong [Centre for Energy Research of the Hungarian Academy of Sciences (EK), 1525 Budapest 114, P.O. Box 49 (Hungary); Berlizov, Andrey [European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), 76125 Karlsruhe, P.O. Box 2340 (Germany)

    2015-09-15

    The {sup 232}U content of various uranium-bearing items was measured using low-background gamma spectrometry. The method is independent of the measurement geometry, sample form and chemical composition. Since {sup 232}U is an artificially produced isotope, it carries information about previous irradiation of the material, which is relevant for nuclear forensics, nuclear safeguards and for nuclear reactor operations. A correlation between the {sup 232}U content and {sup 235}U enrichment of the investigated samples has been established, which is consistent with theoretical predictions. It is also shown how the correlation of the mass ratio {sup 232}U/{sup 235}U vs. {sup 235}U content can be used to distinguish materials contaminated with reprocessed uranium from materials made of reprocessed uranium.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-07-01

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

  19. Radiometric Analysis of the Ores, Products, Wastewater and Environment of Some Factories in the 10th of Ramadan City

    International Nuclear Information System (INIS)

    El-Mongy, S.A.; El-Fiki, S.A.; Diab, A.M.; Madbouly, A.M.

    1999-01-01

    This work aims at radiological assessment of environment of some industrial activities of the 10 Th of Ramadan City, Ores. final products, waste environmental samples (soil and plant) of five factories: Heavy industries, Ceramics, Granite, detergents and Sponge were collected and analyzed by using γ Spectroscopy. The results show that 10 K , 238 U series and 2 3 2 Th series are found in some of the collected factories samples with different concentrations. The results indicate that 10 K, 238 U series. 232 Th series and the man-made 137 Cs are found in all the soil samples. While the collected plants samples contain 40 K only. The radioactivity levels in the water samples are lower than the UNSCEAR data. It is concluded that the industrial activities did not contribute in increasing of the natural radioactive levels of the city environment

  20. Determination of the activity of the uranium isotopes U-234, U-235 and U-238 in environmental samples by alpha spectrometry

    International Nuclear Information System (INIS)

    Kromphorn, G.

    1996-02-01

    Different materials containing urandium are regularly investigated in the Laboratory for Environmental Radioactivity of the Physikalisch-Technische Bundesanstalt (PTB) with respect to the activity of the uranium isotopes ( 234 U, 235 U, and 238 U). Moreover for reasons of quality assurance, the PTB takes part in international comparisons where also uranium contents are to be determined in environmental samples and in the framework of which reference materials can be certified. Finally in national comparisons the PTB has the task to determine values of the specific activity for the different isotopes which can play the role of nominal (orientation) values. The single steps of uranium analyses are described after a compilation of the most important data of the uranium isotopes contained in natural uranium: The use of 232 U as tracer, the chemical separation analytics, the production of α-sources and the measuring methods. Analyses of a soil sample and a waste water sample with respect to their specific uranium activity have been chosen as examples of a practical application. (orig.) [de

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

    International Nuclear Information System (INIS)

    Mitsuda, Hiroshi

    1984-01-01

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

  2. Applications of neutron activation analysis in determination of natural and man-made radionuclides, including PA-231

    Science.gov (United States)

    Byrne, A. R.; Benedik, L.

    1999-01-01

    Neutron activation analysis (NAA), being essentially an isotopic and not an elemental method of analysis, is capable of determining a number of important radionuclides of radioecological interest by transformation into another, more easily quantifiable radionuclide. The nuclear characteristics which favour this technique may be summarized in an advantage factor relative to radiometric analysis of the original radioanalyte. Well known or hardly known examples include235U,238U,232Th,230Th,129I,99Tc,237Np and231Pa; a number of these are discussed and illustrated in analysis of real samples of environmental and biological origin. In particular, determination of231Pa by RNAA was performed using both postirradiation and preseparation methods. Application of INAA to enable the use of238U and232Th as endogenous (internal) radiotracers in alpha spectrometric analyses of uranium and thorium radioisotopes in radioecological studies is described, also allowing independent data sets to be obtained for quality control.

  3. Measurement of the 232Th-series activity in gas sockets

    International Nuclear Information System (INIS)

    Sutarman, I.

    1995-01-01

    The activity of 232 Th and its daughters in Th-based gas sockets is required for health risk assessment. By absolute measurement of the 228 Ac-and 212 Pb/ 208 Tl-activities, the total activity of the sockets can be assessed. It is governed by 228 Ra and 228 Th and the product age. (author) 1 fig.; 2 tabs

  4. Hydrogeochemical applications of natural isotope of the U (4n+2) and Th(4n) series in Morro do Ferro, Pocos de Caldas (MG), Brazil

    International Nuclear Information System (INIS)

    Bonotto, D.M.

    1987-01-01

    Uranium and thorium isotopic analysis were performed on well spoils of the ore body at Morro do Ferro, Pocos de Caldas (MG), Brazil, using groundwater from several boreholes in the area and surface water from a stream and that originates at the base of the hill. For uranium and thorium extraction, a chemical process was applied to samples; activites of 228 Th and 232 Th radioisotopes (4n+2 series) were determined by alpha spectrometry. The uranium concentration and 234 U/ 238 U isotope ratio in groundwater were applied to developed models for deducing proportions of water in a mixture and for characterizing uranium accumulation. The correlation between variability in concentration of uranium dissolved in groundwater and alteration of the level of the water table due to infiltration of rainfall was observed. Chemical analysis of the major and minor compounds for groundwater of the ore body zone were done. (Author) [pt

  5. Benchmark testing calculations for 232Th

    International Nuclear Information System (INIS)

    Liu Ping

    2003-01-01

    The cross sections of 232 Th from CNDC and JENDL-3.3 were processed with NJOY97.45 code in the ACE format for the continuous-energy Monte Carlo Code MCNP4C. The K eff values and central reaction rates based on CENDL-3.0, JENDL-3.3 and ENDF/B-6.2 were calculated using MCNP4C code for benchmark assembly, and the comparisons with experimental results are given. (author)

  6. @u234@@Th scavenging and particle export fluxes from the upper 100 m of the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sarin, M.M.; Rengarajan, R.; Ramaswamy, V.

    for the upper 100 m yields a mean scavenging residence time of ~k30 days and a removal rate of ~k 3400 dpm m@u-2@@ d@u-1@@ for @u234@@Th, from dissolved to particulate phases. The deficiency of total @u234@@Th (dissolved + particulate) relative to @u238@@U...

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

    Science.gov (United States)

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

    2017-12-01

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

  8. Analysis of radioactivity in coal, cinders, fly ash and discharges from the stack

    International Nuclear Information System (INIS)

    Meide, A.

    1985-01-01

    Gamma measurements of coal samples originating from several supplying countries proved that the South African coal has about double U-238 and Ra-226 concentration and about treble Th-232 concentration compared to coal from the other countries. Gamma measurements of coal, cinders and fly ash samples from five coal-fueled plants indicate somewhat higher concentrations of Th-232 in cinders and U-238 and Th-232 in fly ashes than those described in literature. The ratio Po-210/Pb-210 was about 2 for fly ash particulates <35μ. A positive correlation between ash percentage and radioactivity of coal might be assumed. (EG)

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  10. Behavior of uranium and thorium isotopes in soils of the Boreon area, Mercantour Massif (S.E. France). Leaching and weathering rate modeling

    International Nuclear Information System (INIS)

    Rezzoug, S.; Michel, H.; Barci-Funel, G.; Barci, V.; Fernex, F.

    2009-01-01

    Four cores were collected in weathered rocks and soils in the Boreon forest area (1765 m, Mercantour Massif, France). The samples were analyzed for the isotopes 230 Th, 232 Th, 234 U and 238 U. The activity and isotopic ratio profiles suggest that uranium was mobilized (leaching and precipitation) during the weathering process, as well as thorium but in a much less proportion. A model was drawn up to evaluate the U leaching rate and the time that some levels of the weathered rocks have been subjected to weathering. It utilizes LATHAM and SCHWARCZ's two equations,15 expressed as 234 U/ 238 U and 230 Th/ 238 U activity ratios, which assume that the alpha recoil effect allows easier leaching for 234 U than 238 U and no Th mobility. But this last assumption does not correspond to the observations made in the Boreon area, since it appears that in some soil deeper layers 230 Th and 228 Th are in radioactive deficit relatively to their parents. As there are four unknown quantities (the time, the leaching rates of 238 U, 234 U, 230 Th), the problem to be solved requires two more equations; these can be obtained utilizing the U activity ratio in water, and taking into account the 232 Th behavior. In some sites the 238 U leaching rate is high in deeper soil levels (near the fresh rocks); this would correspond to a loss of half the U amount in less than 24 000 years. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

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

    International Nuclear Information System (INIS)

    Silva, P.S.C.; Mazzilli, B.P.; Favaro, D.I.T.

    2004-01-01

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

  13. Fission cross sections of some thorium, uranium, neptunium and plutonium isotopes relative to /sup 235/U

    Energy Technology Data Exchange (ETDEWEB)

    Meadows, J W

    1983-10-01

    Earlier results from the measurements, at this Laboratory, of the fission cross sections of /sup 230/Th, /sup 232/Th, /sup 233/U, /sup 234/U, /sup 236/U, /sup 238/U, /sup 237/Np, /sup 239/Pu, /sup 240/Pu, and /sup 242/Pu relative to /sup 235/U are reviewed with revisions to include changes in data processing procedures, alpha half lives and thermal fission cross sections. Some new data have also been included. The current experimental methods and procedures and the sample assay methods are described in detail and the sources of error are presented in a systematic manner. 38 references.

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

  15. Evaluation of metal and radionuclide data from neutron activation and acid-digestion-based spectrometry analyses of background soils. Significance in environmental restoration

    International Nuclear Information System (INIS)

    Lee, S.Y.; Watkins, D.R.; Jackson, B.L.; Schmoyer, R.L.; Lietzke, D.A.; Burgoa, B.B.; Branson, J.T.; Ammons, J.T.

    1997-01-01

    A faster, more cost-effective, and higher-quality data acquisition for natural background-level metals and radionuclides in soils is needed for remedial investigations of contaminated sites. The advantages and disadvantages of neutron activation analysis (NAA) compared with those of acid-digestion-based spectrometry (ADS) methods were evaluated using Al, Sb, As, Cr, Co, Fe, Mg, Mn, Hg, K, Ag, 232 Th, 235 U, 238 U, V, and Zn data. The ADS methods used for this project were inductively coupled plasma (ICP), ICP-mass spectrometry (ICP-MS), and alpha spectrometry. Scatter plots showed that the NAA results for As, Co, Fe, Mn, 232 Th, and 238 U are reasonably correlated with the results from the other analytical methods. Compared to NAA, however, the ADS methods underestimated Al, Cr, Mg, K, V, and Zn. Because of the high detection limits of ADS methods, the scatter plots of Sb, Hg, and Ag did not show a definite relationship. The NAA results were highly correlated with the alpha spectrometry results for 232T h and 238 U but poorly correlated for 235 U. The NAA, including the delayed neutron counting, was a far superior technique for quantifying background levels of radionuclides ( 232 Th, 235 U, and 238 U) and metals (Al, Cr, Mg, K, V, and Zn) in soils. (author)

  16. Natural radioactivity measurements in the central region of Colombia

    International Nuclear Information System (INIS)

    Cortes, M. L.; Mendoza, E. F.; Cristancho, F.

    2009-01-01

    The natural radionuclides 238 U, 232 Th and 40 K are the most important γ ray emitters present in the earth crust and its concentration depends mainly on the processes of mineralization and geological formation that occur in nature. The determination of such concentrations is important because it allow us to know the radiation exposure of human beings in different regions and thus monitor the dose levels received by the population. In this work the concentrations of 238 U, 232 Th and 40 K for two different places in the central region of Colombia are presented. The obtained values for 238 U concentration are between 20 and 30 ppm, for 232 Th between 70 and 130 ppm and for 40 K between 5 - 7 %. These values are comparable with other works, but further measurements are needed to characterize the radionuclides concentrations in Colombia. (Author)

  17. Certified reference materials for radionuclides in Bikini Atoll sediment (IAEA-410) and Pacific Ocean sediment (IAEA-412)

    DEFF Research Database (Denmark)

    Pham, M. K.; van Beek, P.; Carvalho, F. P.

    2016-01-01

    The preparation and characterization of certified reference materials (CRMs) for radionuclide content in sediments collected offshore of Bikini Atoll (IAEA-410) and in the open northwest Pacific Ocean (IAEA-412) are described and the results of the certification process are presented. The certified...... radionuclides include: 40K, 210Pb (210Po), 226Ra, 228Ra, 228Th, 232Th, 234U, 238U, 239Pu, 239+240Pu and 241Am for IAEA-410 and 40K, 137Cs, 210Pb (210Po), 226Ra, 228Ra, 228Th, 232Th, 235U, 238U, 239Pu, 240Pu and 239+240Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes...

  18. Sub-barrier photofission of 238U

    International Nuclear Information System (INIS)

    Bhandari, B.S.

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-01-15

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

  20. U-Th Burial Dates on Ostrich Eggshell

    Science.gov (United States)

    Sharp, W. D.; Fylstra, N. D.; Tryon, C. A.; Faith, J. T.; Peppe, D. J.

    2015-12-01

    Obtaining precise and accurate dates at archaeological sites beyond the range of radiocarbon dating is challenging but essential for understanding human origins. Eggshells of ratites (large flightless birds including ostrich, emu and others) are common in many archaeological sequences in Africa, Australia and elsewhere. Ancient eggshells are geochemically suitable for the U-Th technique (1), which has about ten times the range of radiocarbon dating (>500 rather than 50 ka), making eggshells attractive dating targets. Moreover, C and N isotopic studies of eggshell provide insights into paleovegetation and paleoprecipitation central to assessing past human-environment interactions (2,3). But until now, U-Th dates on ratite eggshell have not accounted for the secondary origin of essentially all of their U. We report a novel approach to U-Th dating of eggshell that explicitly accounts for secondary U uptake that begins with burial. Using ostrich eggshell (OES) from Pleistocene-Holocene east African sites, we have measured U and 232Th concentration profiles across OES by laser ablation ICP-MS. U commonly peaks at 10s to 100s of ppb and varies 10-fold or more across the ~2 mm thickness of OES, with gradients modulated by the layered structure of the eggshell. Common Th is high near the shell surfaces, but low in the middle "pallisade" layer of OES, making it optimal for U-Th dating. We determine U-Th ages along the U concentration gradient by solution ICP-MS analyses of two or more fractions of the pallisade layer. We then estimate OES burial dates using a simple model for diffusive uptake of uranium. Comparing such "U-Th burial dates" with radiocarbon dates for OES calcite from the same shells, we find good agreement in 7 out of 9 cases, consistent with rapid burial and confirming the accuracy of the approach. The remaining 2 eggshells have anomalous patterns of apparent ages that reveal they are unsuitable for U-Th dating, thereby providing reliability criteria innate

  1. Preliminary Determination of Natural Radioactivity Levels of the State of Qatar using High-Resolution Gamma-ray Spectrometry

    International Nuclear Information System (INIS)

    Al-Sulaiti, H.A.; Regan, P.H.; Bradley, D.A.; Matthews, M.; Santawamaitre, T.; Malain, D.

    2009-01-01

    The State of Qatar is a peninsula with a total area of 11,437 km 2 which lies over a geological formation comprising a sequence of limestone, chalk, clay and gypsum. Establishing a baseline for the radioactivity concentration in Qatar's soil is the main purpose behind the present study. The project is focused on obtaining measurements of representative soil samples from various areas in Qatar to establish concentrations of the 235 U, 238 U and 232 Th natural decay chains and also the long-lived naturally occurring radionuclide 40 K. The 235 U, 238 U, 232 Th and 40 K concentrations have been measured via high-resolution gamma-ray spectrometry using a hyper-pure germanium detector situated in a low-background environment with a copper inner-plated passive lead shield. A wide range of different gamma-ray energy transitions lines arising from the multiple decay products from the 235 U, 238 U and 232 Th decay chains have been analyzed separately to obtain more statistically significant overall results

  2. Determination of the activity concentration of {sup 230}Th in phosphoric acids produced in Brazil; Determinação da concentração de atividade de {sup 230}Th em ácidos fosfóricos produzidos no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Taddei, M.H.T.; Ferreira, M.T.; Fukuma, H.T.; Xavier, T.T.; Sousa, F.V.T.S., E-mail: tatianattx@gmail.com [Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas. Radioquimica

    2017-07-01

    The high uranium phosphate rock from Itataia, Brazil, was processed using the wet route in the dihydrate system to manufacture phosphoric acid. The uranium contained in phosphoric acid was recovered by the solvent extraction technique. The distribution of the long half-life radionuclides from the decay series of {sup 238}U and {sup 232}Th were evaluated in these processes. The {sup 26}Ra, {sup 228}Ra and {sup 210}Pb radionuclides were found predominantly in phosphogypsum, while the isotopes of {sup 228}Th, {sup 230}Th and {sup 232}Th predominated in phosphoric acid after extracting uranium. The main concern in the commercialization of phosphoric acid that will be produced in the Itataia plant is in relation to the content of {sup 230}Th. This work determined the content of these radionuclides in phosphoric acid from different locations in the country in order to compare.

  3. Natural radioactivity assessment of surface sediments in the Yangtze Estuary

    International Nuclear Information System (INIS)

    Wang, Jinlong; Du, Jinzhou; Bi, Qianqian

    2017-01-01

    The activities of the natural radionuclides ( 238 U, 232 Th, 226 Ra and 40 K) of the surface sediments in the Yangtze Estuary were determined and used to evaluate radiation hazards in the study area. The of activities of 238 U, 232 Th, 226 Ra and 40 K ranges from 14.1 to 62.3, 26.1 to 71.9, 13.7 to 52.3, and 392 to 898 Bq kg −1 , respectively, which were comparable to values of other regions in China. The activities of 232 Th, 40 K and 226 Ra were clearly different from the global recommended values. The radium equivalent activity was less than the recommended limit of 370 Bq kg −1 ; therefore, the sediment in this area can be safely used for reclamation. The external hazard index values were less than one. The average absorbed gamma dose rate and annual effective dose equivalent values were slightly greater than the world average value. 226 Ra/ 238 U and 232 Th/ 238 U ratios could potentially be applied for tracing sediment source. - Highlights: • The natural radioactivity of surface sediments in the Yangtze Estuary was observed. • The radiological hazards of the sediments are insignificant in this study area. • The ratios of natural radionuclides can potentially be applied for sediment source.

  4. Baseline assessment of doses and risk due to natural radionuclides in edible biota of Domiasiat, Meghalaya, India

    International Nuclear Information System (INIS)

    Kumar, N.; Chaturvedi, S.S.; Jha, S.K.

    2011-01-01

    Radiation dose-risk assessment was carried out for cereal species Brassica compestris var. dichotoma, Oryza sativa var. Shalum1, Zea mays, Lactuca indica, Cumunis sativum, and Clocasia esculanta due to naturally available radionuclides 40 K, 238 U and 232 Th in Domiasiat area. The activity in biota and corresponding soil was measured by precipitation method using NaI(TI) detector. Transfer factor (TF) was for Oryza spp. (1.00E-01- 40 K, 8.76E-05- 232 Th, and 9.11E-05- 238 U), for Brassica spp. (5.39E-01- 40 K, 8.17E-04- 232 Th and 2.96E-04- 238 U) and for Zea spp. (3.41E-01- 40 K, 5.84E-05- 232 Th, 8.87E-05- 238 U) etc., respectively. A detailed physio-morphological study of the biota and extensive investigation of ecosystem was carried out for assessment. The data was modeled using FASSET for dose estimation and obtained total dose was 1.58E-04 μGy h -1 in Oryza spp., 2.87E-04 μGy h -1 Brassica spp. and 6.90E-03 μGy h -1 in Zea spp. etc. The dose was compared with the UNSCEAR dataset for screening level dose for biota. Zea spp. was more susceptible for the chronic radiation exposure. (author)

  5. 235U and 238U (n,xn gamma) cross-sections

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  6. 222Rn content and 234U/238U activity ratio in groundwaters

    International Nuclear Information System (INIS)

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

    1990-01-01

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

  7. The measurement of activities of 226Ra, 232Th, 40K in phosphogypsum by gamma ray spectrometry

    International Nuclear Information System (INIS)

    Parmaksiz, A.

    2004-06-01

    Phosphatic fertilizers are produced from the industrial processing of rock phosphate ores which are known to contain naturally occuring radionuclides such as 238 U and its daughter products. A high volume by-product known as phosphogypsum (PG) from the production of phosphoric acid and phosphate fertilizer causes serious storage and environmental problems in phosphoric acid industries. During the phosphoric acid production process, 226 Ra (t 1/2 =1600 y) ends up in PG which has chemical analogous to calcium periodical table. Since the stockpiles of PG near the phosphatic fertilizer plants are huge amounts, the radioactivity contained in PG has to measured in view of environmental radioactivity problem. In this work, the natural radioactivity in eighty PG samples, issued from a stock of about 60.000 tones was measured by a high resolution gamma ray spectrometer with a HPGe detector. The averaged activity of 226 Ra in PG has been found to be 546 Bq.kg -1 . However, the activities of 232 Th and 40 K measured in PG samples are negligibly small. The extra gamma radiation dose rate arising from 1 - 1.5 kg of PG is estimated to be about 241 nGy/h from 1 m ground level applied in 1 m 2 surface area of field

  8. 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.

  9. 226Ra/238U disequilibrium in an upland organic soil exhibiting elevated natural radioactivity

    International Nuclear Information System (INIS)

    Dowdall, M.; O'Dea, J.

    2002-01-01

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

  10. Is the beagle dog an appropriate experimental animal for extrapolating data to humans on organ distribution patterns of U, Th, and Pu

    International Nuclear Information System (INIS)

    Singh, N.P.; Wrenn, M.E.

    1989-01-01

    Concentrations and organ distribution patterns of alpha-emitting isotopes of U (238U and 234U), Th (232Th, 230Th, and 228Th), and Pu (239,240Pu) were determined for beagle dogs of our colony. The dogs were exposed to environmental levels of U and Th isotopes through ingestion (food and water) and inhalation to stimulate environmental exposures of the general human population. The organ distribution patterns of these radionuclides in beagles are compared to patterns in humans to determine if it is appropriate to extrapolate organ content data from beagles to humans. The results indicated that approximately 80% of the U and Th accumulated in bone in both species. The organ content percentages of these radionuclides in soft tissues such as liver, kidney, etc. of both species were comparable. The human lung contained higher percentages of U and Th than the beagle lung, perhaps because the longer life span of humans resulted in a longer exposure time. If the U and Th content of dog lung is normalized to an exposure time of 58 y and 63 y, median ages of the U and Th study populations, respectively, the lung content for both species is comparable. The organ content of 239,240Pu in humans and beagles differed slightly. In the beagle, the liver contained more than 60%, and the skeleton contained less than 40% of the Pu body content. In humans, the liver contained approximately 37%, and the skeleton contained approximately 58% of the body content. This difference may have been due to differences in the mode of intake of Pu in each species or to differences in the chemical form of Pu. In general, the results suggest that the beagle may be an appropriate experimental animal from which to extrapolate data to humans with reference to the percentage of U, Th, and Pu found in the organs

  11. Fast fission assisted ignition of thermonuclear microexplosions

    International Nuclear Information System (INIS)

    Winterberg, F.

    2006-01-01

    It is shown that the requirements for fast ignition of thermonuclear microexplosions can be substantially relaxed if the deuterium-tritium (DT) hot spot is placed inside a shell of U-238 (Th-232). An intense laser - or particle beam-projected into the shell leads to a large temperature gradient between the hot DT and the cold U-238 (Th-232), driving thermomagnetic currents by the Nernst effect, with magnetic fields large enough to entrap within the hot spot the α-particles of the DT fusion reaction. The fast fission reactions in the U-238 (Th-232) shell implode about 1/2 of the shell onto the DT, increasing its density and reaction rate. With the magnetic field generated by the Nernst effect, there is no need to connect the target to a large current carrying transmission line, as it is required for magnetized target fusion, solving the so-called ''stand off'' problem for thermonuclear microexplosions. (orig.)

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

    International Nuclear Information System (INIS)

    Kawamura, Hisao; Shiraishi, Kunio; Igarashi, Yasuhito; Yamamoto, Masayoshi; Tanaka, Gi-ichiro.

    1994-01-01

    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 239 Pu+ 240 Pu determination including our result was published. Alpha spectrometric determinations of 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 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 μSv, respectively 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 232 Th and 238 U by the newly developed ICP-MS technique. The daily intake per person of 232 Th and 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 μSv for 232 Th and 0.3 μSv for 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. U-Th isotopic systematics at 13deg N east Pacific Ridge segment

    International Nuclear Information System (INIS)

    Ben Othman, D.; Allegre, C.J.

    1990-01-01

    Fresh basaltic glasses have been analyzed for U-Th disequilibrium systematics as part of an extensive study on the East Pacific Rise (EPR) at 12deg 45'N. These samples are well described in terms of major and trace elements as well as in Nd, Pb and Sr isotopes. Our results show significant heterogeneities in the mantle source at a small scale, and show heterogeneities at larger scales also when compared to other EPR data. U and Th concentration and isotopic data rule out fractional crystallization as a main process and support a mixing model in agreement with the marble cake model developed by Allegre and Turcotte and constrained by trace elements and Nd, Sr and Pb isotopes on the same samples by Prinzhofer et al. Based on the high ( 230 Th/ 232 Th) isotopic ratios on recent tholeiites especially the Th/U values inferred for their sources clearly show that the upper mantle Th/U has decreased with time. (orig.)

  14. Radionuclide analysis in the soil of Kumaun Himalaya, India, using gamma ray spectrometry

    International Nuclear Information System (INIS)

    Ramola, R.C.; Prasad, Ganesh; Gusain, G.S.; Choubey, V.M.; Tosheva, Z.; Kies, A.

    2011-01-01

    Environmental release of low levels of radioactivity can occur as a consequence of normal radionuclides present in the earth's crust. We present here the results of a survey undertaken in 2003 on the radionuclide concentration in different rock formations in the eastern part of Kumaun Himalaya. The activity concentration and gamma-absorbed dose rates of the terrestrial radionuclides caused by 226 Ra, 232 Th and 40 K were determined in the soil samples collected from the eastern part of Kumaun Himalaya. The mean concentration of 238 U and 232 Th in the earth's crust varied from 0.5 to 5 ppm (6 to 60 Bq/kg) and 2 to 20 ppm (8 to 80 Bq/kg) respectively. The reported activity concentration for the different rock formations varied from 32.6 to 1305.5 Bq/kg for 238 U, 16.3 to 136.3 Bq/kg for 232 Th and 124.6 to 1758.0 Bq/kg for 40 K. The distribution of the radionuclides varied with rock type due to different chemical properties of the measured radionuclides and the rocks. The result shows that high activity levels were found in Saryu Formation consisting of augen-gneiss, granite interbedded with schists and flaggy quartzite. The total air-absorbed dose rate in air above 1 m height was calculated from the three radionuclides ( 226 Ra, 232 Th and 40 K), which varied from 39.1 to 226.8 nGy h -1 . The internal and external health-hazard indices were calculated based on the concentration of 226 Ra, 232 Th and 40 K. Strong positive correlations were observed between 235 U and 226 Ra, 232 Th and 226 Ra, 40 K and 232 Th as well as 40 K and 226 Ra. However, no significant correlation was observed between 238 U and 226 Ra because of radioactive disequilibrium between them. (author)

  15. Geochemistry and behavior of Natural radionuclides in the Layers Exploitable Phosphate field MerahLahrachOuladAbdoun's Basin - Morocco

    International Nuclear Information System (INIS)

    Fait, E.; Fakhi, S.

    2012-01-01

    The present work is part of research developed on the behavior and the exchange of metals in solid-liquid's interface. It is about clarifying the distribution of stable metals especially radioactive, in this context radiometric analyzes and elementary has been done on all layers exploitable phosphate aged Maastrichtian (-70.6 million years) - Lutetian (-40.4 My) in the center of OuladAbdoun's basin, MerahLahrach's area. The specific activities of 238U, 235U and 232Th and their respective descendants were determined directly by spectrometry gamma and radio-chemically by spectrometry alpha. The results found show an enrichment of radionuclides in the deeper layers who came from the leaching of upper layers. The maximum specific activity of uranium is stored in the deeper layers (layer 3 aged Maastrichtian) who aren't very rich on phosphorus (22.4% P), however the 238U was reached up to 2066144 Bq/kg, equivalent of 16 11 ppm, the layer 1's median presents the low concentrations with 857 39Bq/Kg, equivalent of 703 ppm. The average specific activity of radionuclides identified in the series of exploited phosphates (238U, 232Th, 226Ra, 214Pb and 40K) are respectively (125572Bq/Kg; 309 Bq/Kg; 1285207 Bq/Kg; 102252 Bq/kg and 207 Bq/Kg). The study of mobility and / or accumulation accomplished by exploiting the variation of isotopic ratios 230Th/238U, 234U/238U and 232Th/238U as a function on the depth of phosphate's layers and the lithology of these samples, has allowed to identify the phenomena of exchanging between the layers of the system studied.

  16. Environmental evolution records reflected by radionuclides in the sediment of coastal wetlands: A case study in the Yellow River Estuary wetland.

    Science.gov (United States)

    Wang, Qidong; Song, Jinming; Li, Xuegang; Yuan, Huamao; Li, Ning; Cao, Lei

    2016-10-01

    Vertical profiles of environmental radionuclides ( 210 Pb, 137 Cs, 238 U, 232 Th, 226 Ra and 4 0 K) in a sediment core (Y1) of the Yellow River Estuary wetland were investigated to assess whether environmental evolutions in the coastal wetland could be recorded by the distributions of radionuclides. Based on 210 Pb and 137 Cs dating, the average sedimentation rate of core Y1 was estimated to be 1.0 cm y -1 . Vertical distributions of natural radionuclides ( 238 U, 232 Th, 226 Ra and 40 K) changed dramatically, reflecting great changes in sediment input. Concentrations of 238 U, 232 Th, 226 Ra and 40 K all had significant positive relationships with organic matter and clay content, but their distributions were determined by different factors. Factor analysis showed that 238 U was determined by the river sediment input while 226 Ra was mainly affected by the seawater erosion. Environmental changes such as river channel migrations and sediment discharge variations could always cause changes in the concentrations of radionuclides. High concentrations of 238 U and 226 Ra were consistent with high accretion rate. Frequent seawater intrusion decreased the concentration of 226 Ra significantly. The value of 238 U/ 226 Ra tended to be higher when the sedimentation rate was low and tide intrusion was frequent. In summary, environmental evolutions in the estuary coastal wetland could be recorded by the vertical profiles of natural radionuclides. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Radionuclides concentration in foods in Peninsular Malaysia

    International Nuclear Information System (INIS)

    Zalina Laili; Muhamat Omar; Mohd Nahar Othman; Md Suhaimi Elias; Esther Philip, Mohd Zaidi Ibrahim; Faizal Azrin Abdul Razalim; Azmi Hassan

    2006-01-01

    The concentrations of natural radionuclides (U-238, Th-232, Ra-226, Ra-228 and K-40) and artificial radionuclides (Cs-137) in fresh, dried and cooked foodstuffs from 30 major towns in Peninsular Malaysia were determined by gamma spectrometry system and Instrumental Neutron Activation Analysis (INAA) technique. A total of 232 samples representing a typical Malaysian community diet were analysed. The results showed that most of the samples contained only natural radionuclides. The percentage of radionuclides detected in the samples were found about 2% for U-238, 9% for Th-232, 49% for Ra-226, 77% for Ra-228, 99% for K-40 and 15% for Cs-137. The radionuclide concentrations were in the ranges of <6.1 - 29.3, <2.0 - 55.8, <0.1 - 34.4, <0.1 - 41, <0.1- 2552.3 and < 0.1 - 6.6 Bq/Kg dry weight for U-238, Th-232, Ra-226, Ra-228 and K-40 and Cs-137 respectively. The study revealed that most of the foodstuffs did not contain U-238. Lentils were found to contain significant concentration of Th-232 (4 - 49 Bq/kg) and can be considered as thorium accumulators. The concentrations of Ra-226 and Ra-228 in leafy vegetables were higher than the fruit and root vegetables. These data can be used as a reference for future food radioactivity monitoring. As edible mushroom and fern had high concentrations of Cs-137, indicating their high ability to accumulate Cs-137, they could be used as indicator plants in the event of radioactive fall outs

  18. Vegetation-derived insights on the mobilization and potential transport of radionuclides from the Nopal I natural analog site, Mexico

    International Nuclear Information System (INIS)

    Leslie, B.W.; Pickett, D.A.; Pearcy, E.C.

    1999-01-01

    The Nopal I uranium (U) deposit, Pena Blanca, Mexico is a source term and contaminant transport natural analog to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. In an attempt to characterize the mobilization and potential transport of radionuclides in the unsaturated zone at the Nopal I deposit, vegetation growing on ore piles was analyzed for 238 U, 235 U, and 232 Th decay-series isotopes. Specimens of Phacelia robusta growing on high-grade piles of U ore were collected and analyzed by alpha autoradiography, and by alpha and gamma spectrometry. Activities for U, thorium (Th), and radium (Ra) isotopes (Bq/kg dried plant) were 300, 1,000, and 7,000 for 238 U, 230 Th, and 226 Ra, respectively. The 226 Ra activities in these specimens are among the highest ever measured for plants; furthermore, the plant-to-soil 226 Ra concentration ratio is higher than expected. These results demonstrate the large mobility and bio-availability of Ra in the Nopal I environment, and support previous indications of recent loss of 226 Ra from the ore body. Comparison between the activities of 238 U and 232 Th decay-chain Th isotopes in the plants and in the ore substrate indicate that relative mobilization into pore solutions of 228 Th > 230 Th > 232 Th, in a ratio of about 50--25:4:1, respectively. The similarity of the plant's 234 U/ 238 U activity ratio (∼1.2) to that of a caliche deposit that formed adjacent to the Nopal ore body around 54 ka suggests the 234 U/ 238 U activity ratio of U released from the ore is approximately 1.2. The U and 226 Ra isotope activities of the plants and ore substrate, and solubility considerations, are used to assess a source term model of the potential Yucca Mountain repository. These results suggest the use of a natural analog source term model in performance assessments may be non-conservative

  19. Emanation of /sup 232/U daughter products from submicrometer particles of uranium oxide and thorium dioxide by nuclear recoil and inert gas diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, M.A.; Cuddihy, R.G. (Lovelace Biomedical and Environmental Research Inst., Albuquerque, NM (USA). Inhalation Toxicology Research Inst.)

    1983-01-01

    Emanation of /sup 232/U daughter products by nuclear recoil and inert gas diffusion from spherical, submicrometer particles of uranium oxide and thorium dioxide was studied. Monodisperse samples of particles containing 1% /sup 232/U and having physical diameters between 0.1 and 1 ..mu..m were used for the emanation measurements. Thorium-228 ions recoiling from the particles after alpha-decay of /sup 232/U were collected electrostatically on a recoil cathode. Radon-220 diffusing from the particles was swept by an airstream into a 4 l. chamber where the /sup 220/Rn daughters were collected on a second cathode. Mathematical models of radionuclide emanation from spherical particles were used to calculate the recoil range of /sup 228/Th and the diffusion coefficient of /sup 220/Rn in the particle matrix. A /sup 228/Th recoil range of 0.02 ..mu..m and a /sup 220/Rn diffusion coefficient of 3 x 10/sup -14/ cm/sup 2//sec were obtained in both uranium oxide and thorium dioxide particles.

  20. 238U + n resolved resonance energies

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  1. 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)

    Parami, Vangeline Kinilitan

    2008-04-01

    ). Except for Plant C samples, 228 Ra, 228 Th and 40 K were about equallypartitioned between BA and FA samples; 238 U had consistently higher partitioning in all FA samples than BA samples; 226 Ra and 232 Th 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 226 Ra with 238 U (R 2 =0.98), and 228 Ra with 232 Th (R 2 =0.94). Correspondence between ICP-MS and HPGe results were generally high with slopes of 0.90 and zero intercept for both 226 Ra vs 238 U and 228 Ra vs 232 Th. Correlations between NIRS HPGe and PNRI HPGe were also very high for 226 Ra (R 2 =0.93) and 228 Ra (R 2 =0.91), and high for 40 K (R 2 =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 226 Ra, 228 Ra, and 40 K 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

  2. Radionuclide activities and radiological impact from the intake of milk, wheat flour, tea and coffee

    International Nuclear Information System (INIS)

    Nik Nadia Hazwani Nek Kamal; Amran Abdul Majid

    2013-01-01

    Full-text: The annual intake of four naturally occurring radionuclides 226 Ra, 238 U, 232 Th and 40 K from powdered milk, wheat flour, tea and coffee for Malaysian population were estimated using gamma spectrometry system. The radionuclides annual intake of 226 Ra ranged from 6 to 35.7 Bq, 232 Th ranged from 7.6 to 57.7 Bq, 238 U ranged from 6.3 to 63.7 Bq and 40 K ranged from 771.8 to 1707.5 Bq for adults. The means of these intakes were 28.8 Bq for 226 Ra, 38.5 Bq for 232 Th, 28.1 Bq for 238 U and 2921.1 Bq for the 40 K. The annual intake of radionuclide for infants were found to be 66.2 Bq for 226 Ra, 71.6 Bq for 232 Th, 23 Bq for 238 U and 7774.8 Bq for 40 K. the annual internal dose for infants from the intake of powdered milk were 63.5 μSv for 226 Ra, 32.2 μSv for 232 Th, 2.8 μSv for 238 U and 326.5 μSv for 40 K. The measured values also gives annual internal dose of 13.7 μSv 226 Ra, 19 μSv for 232 Th, 4 μSv for 238 U and 24.2 μSv for 40 K 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)

  3. Analysing of 228Th, 232Th, 228Ra in human bone tissues for the purpose of determining the post mortal interval

    International Nuclear Information System (INIS)

    Kandlbinder, R.; Geissler, V.; Schupfner, R.; Wolfbeis, O.; Zinka, B.

    2009-01-01

    Bone tissues of thirteen deceased persons were analyzed to determine the activity concentration of the radionuclides 228 Ra, 228 Th, 232 Th and 2 30 Th. The activity ratios enable to assess the post-mortem-interval PMI). The samples were prepared for analysis by incinerating and pulverizing. 228 Ra was directly detected by γ-spectrometry. 2 28 Th, 230 Th, 232 Th were detected by α-spectrometry after radiochemical purification and electrodeposition. It is shown that the method s principally suited to determine the PMI. A minimum of 300 g (wet weight) f human bone tissue is required for the analysis. Counting times are in the range of one to two weeks. (author)

  4. Contribution to the study of the influences of the excitation energy on the characteristics of the fission process

    International Nuclear Information System (INIS)

    Wagemans, C.

    1979-01-01

    Neutron induced and spontaneous fission with neutron energies from 10 -2 to 2.10 5 eV have been studied. Thermal neutron induced fission measurements in Pa 231 , Th 232 , Np 237 , U 233 , U 235 , Pu 239 and Pu 241 are reported. Energy and mass distributions of heavy fission fragments due to the spontaneous fission of Pu 240 are compared to the results obtained by thermal neutron fission of Pu 239 ; the events observed with U 236 , Pu 240 , Pa 232 and Np 238 are explained by the Bohr theory of fission channels. Ternary fission phenomena of U 233 , U 235 , Pu 239 , Pa 231 and Np 237 induced by thermal neutrons are explained and compared to models of Carjan and Feather. (MDC)

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

    International Nuclear Information System (INIS)

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

    1991-01-01

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

  6. Assessment of radiation background level of Shandong basin in east line of northward rerouting of southern river

    International Nuclear Information System (INIS)

    Deng Daping; Xu Jiaang; Zhu Jianguo; Chen Yingmin; Lu Feng; Song Gang; Cao Jingli

    2007-01-01

    Objective: To assess the radiation background levels of Shandong basin in east line of northward rerouting of southern river. Methods: The activity concentrations of gross-alpha, gross-beta, 137 Cs, 238 U, 232 Th, 40 K, 226 Ra and 90 Sr in the samples were measured by national standard methods respectively. The values of the dose conversion factor given by UNSCEAR 2000 were adopted for dose estimation. Results: The average activity concentrations of gross-alpha, gross-beta, 137 Cs, 238 U, 232 Th, 40 K, 226 Ra and 90 Sr in the samples were pooled in order to analyze dose estimation. The committed effective doses of the 226 Ra, 238 U, 90 Sr, 232 Th and 137 Cs from lake water for residents are 1.46, 4.95 x 10 -1 , 1.24 x 10 -1 , 2.58 x 10 -2 and 7.93 x 10 -3 μSv per year respectively. The committed effective doses of the 226 Ra, 238 U and 90 Sr from cyprinoid fish are 5.49 x 10 -2 , 3.69 x 10 -2 and 1.77 x 10 -2 μSv per year respectively. Conclusions: The results show that the average activity concentrations of gross-alpha, gross-beta, 137 Cs, 238 U, 232 Th, 40 K, 226 Ra and 90 Sr in the samples from Shandong basin of northward rerouting of southern river are within the background levels. And in the main lake basin, the estimated exposures of public caused by the radionuclide in water and cyprinoid fish are so low that they can be ignored unless there ate some radioactive contamination in the future. (authors)

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

    International Nuclear Information System (INIS)

    Borylo, A.; Skwarzec, B.

    2002-01-01

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

  8. 238U (n,f) measurements below 30 keV

    International Nuclear Information System (INIS)

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

    1975-01-01

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

  9. Proton induced fission of {sup 232}Th at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Gikal, K. B., E-mail: kgikal@mail.ru; Kozulin, E. M.; Bogachev, A. A. [JINR, Flerov Laboratory of Nuclear Reactions (Russian Federation); Burtebaev, N. T.; Edomskiy, A. V. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Itkis, I. M.; Itkis, M. G.; Knyazhev, G. N. [JINR, Flerov Laboratory of Nuclear Reactions (Russian Federation); Kovalchuk, K. V.; Kvochkina, T. N. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Piasecki, E. [Heavy Ion Laboratory of Warsaw University (Poland); Rubchenya, V. A. [University of Jyväskylä, Department of Physics (Finland); Sahiev, S. K. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Trzaska, W. H. [University of Jyväskylä, Department of Physics (Finland); Vardaci, E. [INFN Napoli, Dipartimento di Scienze Fisiche dell’Università di Napoli (Italy)

    2016-12-15

    The mass-energy distributions and cross sections of proton-induced fission of {sup 232}Th have been measured at the proton energies of 7, 10, 13, 20, 40, and 55 MeV. Experiments were carried out at the proton beam of the K-130 cyclotron of the JYFL Accelerator Laboratory of the University of Jyväskylä and U-150m cyclotron of the Institute of Nuclear Physics, Ministry of Energy of the Republic of Kazakhstan. The yields of fission fragments in the mass range A = 60–170 a.m.u. have been measured up to the level of 10−4%. The three humped shape of the mass distribution up has been observed at higher proton energies. The contribution of the symmetric component grows up with increasing proton incident energy; although even at 55 MeV of proton energy the shoulders in the mass energy distribution clearly indicate the asymmetric fission peaks. Evolution of shell structure was observed in the fission fragment mass distributions even at high excitation energy.

  10. Levels of 232Th activity in the South Adriatic Sea marine environment of Montenegro

    International Nuclear Information System (INIS)

    Antovic, N.M.

    2010-01-01

    232 Th activities in the South Adriatic Sea-water, surface sediment, mud with detritus, seagrass (Posidonia oceanica) samples, and the mullet (Mugilidae) species Mugil cephalus, as well as soil and sand from the Montenegrin Coast, were measured using the six-crystal spectrometer PRIPYAT-2M, which has relatively high detection efficiency and a good sensitivity, and allows a short acquisition time, and measuring samples of any shape, without preliminary preparation and calibration measurements for different sample geometries. An average 232 Th activity concentration in surface soil layer is found to be 40.33 Bq kg -1 , while in sand-4.7 Bq kg -1 . The absorbed dose rate in air due to 232 Th gamma radiation from surface soil layer ranged from 11.76 to 63.39 nGy h -1 , with a mean of 24.06 nGy h -1 . Corresponding average annual effective dose rate has been found to be 0.03 mSv y -1 . The absorbed dose rates due to the thorium gamma radiation in air at 1 m above sand surface on the Montenegrin beaches have been found to be from 0.41 to 9.08 nGy h -1 , while annual effective dose rates ranged from 0.0005 to 0.011 mSv y -1 . 232 Th activity concentration in seawater ranged from 0.06 to 0.22 Bq L -1 , as in the mullet (Mugil cephalus) whole individuals from 0.63 to 1.67 Bq kg -1 . Annual intake of 232 Th by human consumers of this fish species has been estimated to provide an effective dose of about 0.003 mSv y -1 . (author)

  11. Radioactivity of soils from north-west side of Stara planina mountain

    International Nuclear Information System (INIS)

    Momcilovic, M.; Dragovic, S.

    2007-01-01

    In this paper specific activities of 238U, 232Th, 40K and 137Cs in soil samples collected from north-west side of Stara planina in 2006 are presented. Specific activities varied between 15.1 and 34.0 Bq/kg for 238U; 16.8 and 44.6 Bq/kg for 232Th; 358 and 765 Bq/kg for 40K and 3.89 and 58.7 Bq/kg for 137Cs. The wide ranges of specific activities are influenced by a variety of geological and ecological features of the investigated area. (author) [sr

  12. The transport of natural radionuclides from soil to plants

    International Nuclear Information System (INIS)

    Bikit, I.; Conkic, Lj.; Slivka, J.; Krmar, M.

    1995-01-01

    The transport and accumulation processes of Ra-226, U-238, Th-232 and K-40 from soil to plants have been studied. Plant samples with consumable parts grown below surface have been bred in natural conditions on soil with enhanced levels of natural radioactivity (barren soil of the uranium mine Gabrovnica-Kalna). An intensive transport of heavy natural radionuclides from soil to the roots was established. The transfer factors for U-238 and Ra-226 have been much bigger than for Th-232. The most intensive uptake was registered for beet root. (author)

  13. Relation of photofission cross sections and delayed neutron photoproduction in the range of E1-giant resonance. Sootnoshenie mezhdu secheniyami fotodeleniya i fotoobrazovaniya zapazdyvayushchikh nejtronov v oblasti E1-gigantskogo rezonansa

    Energy Technology Data Exchange (ETDEWEB)

    Ganich, P P; Parlag, O A; Sikora, D I; Sychev, S I

    1989-03-01

    Relation between yields and cross sections of photofission and photoproduction is studied in order to use them in the methods for analysis of fissile nuclides. Total yield of delayed neutrons from the {sup 232}Th target and ratios of total yields from {sup 238}U and {sup 232}Th targets were measured in the M=300 microtron in 6-18 MeV energy range. Efficiency of the suggested method for refining the {sup 238}U photofission cross sections in the range of E1-giant resonance is shown.

  14. Identifying resuspended sediment in an estuary using the 228Th/232Th activity ratio: the fate of lagoon sediment in the Bega River estuary, Australia

    International Nuclear Information System (INIS)

    Hancock, G.J.

    2000-01-01

    Thorium-series nuclides ( 228 Th and 232 Th) have been used to identify resuspended sediment in the Bega River estuary, south-eastern Australia. A non-conservative increase in concentration of suspended sediment of water in the vicinity of mid-estuary back-flow lagoons was associated with a decrease in the 228 Th/ 232 Th activity ratio (AR) of the suspended sediment. The lagoon sediment is characterized by a low estuarine 228 Th/ 232 Th signature, distinguishing it from freshwater suspended sediment recently delivered to the estuary, and identifying it as the likely source of the additional suspended sediment. Sediment-core 210 TPb profiles show that the lagoons are accumulating sediment, presumably during high river-flow events. However this study indicates that during intervening periods of low flow, 40% of sediment deposited in the lagoons is subsequently resuspended and exported to the lower estuary, and possibly to the ocean. The utility of the 228 Th/ 232 Th AR to quantify sediment resuspension in estuaries is likely to be estuary-dependent, and is controlled by the extent of scavenging of dissolved 228 Th by suspended particles. Copyright (2000) CSIRO Publishing

  15. Laboratory Bioaccumulation, Depuration And Total Dose Rate Of Waterborne Th-232 In Freshwater Fish Of Anabas Testudineus

    International Nuclear Information System (INIS)

    Zal U'yun Wan Mahmood; Norfaizal Mohamed; Nita Salina Abu Bakar

    2014-01-01

    Preliminary results on the study of bioaccumulation, depuration and total dose rate of Th-232 in the whole body of Anabas testudineus are presented. The objective of this study was to evaluate the effect of Th-232 concentration activity on the laboratory bioaccumulation, depuration and total dose rate in Anabas testudineus. Anabas testudineus adults were exposed to different waterborne Th-232 levels: 0 BqL -1 (control), 50 BqL -1 and 100 BqL -1 for 30 day (uptake phase), followed by exposure to radionuclide-free water for 30 days (loss phase). Radionuclide concentration ratios between the whole body levels and water levels, percentage of Th-232 remaining in fish were calculated and total dose rates using ERICA Assessment Tool were also estimated. The results showed the increase of waterborne Th-232 concentration corresponded to a progressive increase of Th accumulation and total dose rate (internal and external) in the whole body of Anabas testudineus. Considering the ERICA dose rate screening value of 10 μGyh -1 , the findings can be concluded the estimated of total dose rate (< 5 μGyh -1 ) in Anabas testudineus is in order of small magnitude. Nevertheless, these preliminary results showed that the Anabas testudineus has a potential to accumulate thorium. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-07-01

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

  17. 10 CFR Appendix B to Part 30 - Quantities 1 of Licensed Material Requiring Labeling

    Science.gov (United States)

    2010-01-01

    ... .1 1 Based on alpha disintegration rate of Th-232, Th-230 and their daughter products. 2 Based on alpha disintegration rate of U-238, U-234, and U-235. Note: For purposes of § 20.303, where there is...

  18. Comparison of potential radiological impacts of 233U and 239Pu fuel cycles

    International Nuclear Information System (INIS)

    Meyer, H.R.; Little, C.A.; Witherspoon, J.P.; Till, J.E.

    1979-01-01

    Nuclear fuel cycles utilizing 233 U are currently the subject of considerable interest in the United States. This paper focuses on the identification of significant differences between the off-site radiological hazards posed by 232 Th/ 233 U (Th/U) and 238 U/ 239 Pu (U/Pu) fuel cycles, and represents a portion of our involvement in the Nonproliferation Alternative Systems Assessment Program (NASAP), to be used in support of the International Fuel Cycle Evaluation (INFCE). The major contributors to radiological dose are likely to be uranium mining and milling (58.5% of total fuel cycle dose), reprocessing (33.9%), and light-water reactor power generation (7.3%). The remainder of the cycle, including enrichment processes, fuel fabrication, transportation, and waste management, contributes only 0.3% to total estimated fuel cycle dose

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-05-25

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

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

    Science.gov (United States)

    Li, Shengjie

    1997-09-01

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

  1. Display of rotational levels near the fission threshold in 232Th(n,f) reaction

    International Nuclear Information System (INIS)

    Blons, J.; Mazur, C.; Paya, D.

    1975-01-01

    The 232 Th(n,f) cross section has been measured relative to that of 235 U up to 5MeV, with a neutron energy resolution of 3keV at 1.6MeV. The angular anisotropy of fission fragments has also been measured in the same energy range with an energy resolution of 6keV at 1,6MeV. The broad vibrational levels located above 1MeV are resolved into sharp structures which are interpreted as rotational states. The rotational constants h 2 /2J of highly deformed 233 Th are found to be 2.45 and 2.65keV at 1.5 and 1.6MeV respectively. These results are interpreted by the possibility of a third minimum in the fission barrier [fr

  2. Natural radioactivity levels of some medical plants used in Ghana

    International Nuclear Information System (INIS)

    Tettey-Larbi, L.

    2012-07-01

    The presence of natural radioactivity in plants constitutes pathway of exposure to human via the food chain. The natural radioactivity concentrations in some selected medicinal plants used in Ghana from the Centre for Scientific Research into Plant Medicine were investigated to determine the activity concentration and the annual committed effective dose due to primodial radionuclide series of 238 U, 232 Th, and the non-serial 40 K. The plants were sampled based on their therapeutic purposes for which they are commonly used. The activity concentration was determined using gamma spectrometry. The results of the analysis indicated an average activity concentration of 238 U, 232 Th, and 40 K in the medicinal plants to be 31.78±2.80 Bq kg -1 , 56.16±2.32 Bq kg -1 and 839.80±11.86 Bq kg -1 respectively. Khaya ivorensis recorded the highest concerntration of 238 U and 232 Th while Lippia multiflora recorded the highest concentration of 40 K. The total annual committed effective doses due to 238 U, 232 Th, and 40 K in medicinal plant samples ranged from 0.026±0.001 to 0.042±0.002 mSv a -1 with an average value of 0.035±001 mSv a -1 . The average annual committed effective dose due to ingestion of the natural radionuclides in the medicinal plant samples were far below the world average annual effective dose of 0.3 mSv a -1 for ingestion of natural radionuclide provided in UNSCEAR 2000 report. Therefore, the radiological hazard associated with intake of the natural radionuclides in the medicinal plants is insignificant. (author)

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

    Science.gov (United States)

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

    2018-02-01

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

  4. 234U/238U activity ratio in groundwater - an indicator of past hydrogeological processes

    International Nuclear Information System (INIS)

    Rasilainen, K.; Suksi, J.; Marcos, N.; Nordman, H.

    2005-01-01

    In this report we describe the long-term behaviour of the uranium isotopes, U-234 and U-238 in groundwater systems. U is a redox sensitive element what for its behaviour is largely controlled by changes in the environmental conditions. A striking feature in U isotope geochemistry is seemingly different behaviour of U-238 and U-234. U isotopes fractionate at the rock-groundwater interface depending on chemical and radiological factors. Changes of the redox conditions in groundwater may thus affect the behaviour of U and its isotopes resulting in variable U concentration and U-234/U-238 activity ratios (AR). We examined the formation of ARs in different groundwater types from a geochemical and a physical/radiological point of view. It was envisaged that AR in groundwater is the consequence of radiological, chemical and hydrological processes. Groundwater condition (redox, flow, etc.) play a very important role in controlling the mass flow of U isotopes. Quantitative α-recoil modelling showed that α-recoil induced flux can be considered insignificant in cases of high-flow. This was an important finding because the exclusion of direct a-recoil means that it is groundwater chemistry and its variations which controls the U-234 mass flow and the formation of AR. Therefore, AR values could be used more confidently to indicate past redox changes and possibly flow paths. (orig.)

  5. 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.

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

    International Nuclear Information System (INIS)

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

    2014-07-01

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

  7. Muon-induced fission

    International Nuclear Information System (INIS)

    Polikanov, S.

    1980-01-01

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

  8. Episodic Holocene eruption of the Salton Buttes rhyolites, California, from paleomagnetic, U-Th, and Ar/Ar dating

    Science.gov (United States)

    Wright, Heather M.; Vazquez, Jorge A.; Champion, Duane E.; Calvert, Andrew T.; Mangan, Margaret T.; Stelten, Mark E.; Cooper, Kari M.; Herzig, Charles; Schriener Jr., Alexander

    2015-01-01

    In the Salton Trough, CA, five rhyolite domes form the Salton Buttes: Mullet Island, Obsidian Butte, Rock Hill, North and South Red Hill, from oldest to youngest. Results presented here include 40Ar/39Ar anorthoclase ages, 238U-230Th zircon crystallization ages, and comparison of remanent paleomagnetic directions with the secular variation curve, which indicate that all domes are Holocene. 238U-230Th zircon crystallization ages are more precise than but within uncertainty of 40Ar/39Ar anorthoclase ages, suggesting that zircon crystallization proceeded until shortly before eruption in all cases except one. Remanent paleomagnetic directions require three eruption periods: (1) Mullet Island, (2) Obsidian Butte, and (3) Rock Hill, North Red Hill, and South Red Hill. Borehole cuttings logs document up to two shallow tephra layers. North and South Red Hills likely erupted within 100 years of each other, with a combined 238U-230Th zircon isochron age of: 2.83 ± 0.60 ka (2 sigma); paleomagnetic evidence suggests this age predates eruption by hundreds of years (1800 cal BP). Rock Hill erupted closely in time to these eruptions. The Obsidian Butte 238U-230Th isochron age (2.86 ± 0.96 ka) is nearly identical to the combined Red Hill age, but its Virtual Geomagnetic Pole position suggests a slightly older age. The age of aphyric Mullet Island dome is the least well constrained: zircon crystals are resorbed and the paleomagnetic direction is most distinct; possible Mullet Island ages include ca. 2300, 5900, 6900, and 7700 cal BP. Our results constrain the duration of Salton Buttes volcanism to between ca. 5900 and 500 years.

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

    International Nuclear Information System (INIS)

    Su Qiong; Cheng Jianping; Diao Lijun; Li Guiqun

    2006-01-01

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

  10. High conversion Th-U{sup 233} fuel assembly for current generation of PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Baldova, D.; Fridman, E. [Reactor Safety Div., Helmholtz-Zentrum Dresden-Rossendorf, POB 510119, Dresden, 01314 (Germany)

    2012-07-01

    This paper presents a preliminary design of a high conversion Th-U{sup 233} fuel assembly applicable for current generation of Pressurized Water Reactor (PWRs). The considered fuel assembly has a typical 17 x 17 PWR lattice. However in order to increase the conversion of Th{sup 232} to U{sup 233}, the assembly was subdivided into the two regions called seed and blanket. The central seed region has a higher than blanket U{sup 233} content and acts as a neutron source for the peripheral blanket region. The latest acts as a U{sup 233} breeder. While the seed fuel pins have a standard dimensions the blanket fuel radius was increased in order to reduce the moderation and to facilitate the resonance neutron absorption in blanket Th{sup 232}. The U{sup 233} content in the seed and blanket regions was optimized to achieve maximal initial to discharged fissile inventory ratio (FIR) taking into account the target fuel cycle length of 12 months with 3-batch reloading scheme. In this study the neutronic calculations were performed on the fuel assembly level using Helios deterministic lattice transport code. The fuel cycle length and the core k{sub eff} were estimated by applying the Non Linear Reactivity Model. The applicability of the HELIOS code for the analysis of the Th-based high conversion designs was confirmed with the help of continuous-energy Monte-Carlo code SERPENT. The results of optimization studies show that for the heterogeneous seed and blanket (SB) fuel assembly the FIR of about 0.95 can be achieved. (authors)

  11. 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.

  12. Uptake and distribution of 232U in peas and barley

    International Nuclear Information System (INIS)

    Schreckhise, R.G.; Cline, J.F.

    1980-01-01

    The uptake of 232 U from soil and its distribution in peas and barley were examined under conditions which isolated root uptake from deposition on aboveground plant parts. Aboveground plant parts were harvested at maturity and analyzed for 232 U content by alpha-energy-analysis. The ratio of concentration (CR) of 232 U in the dry barley seeds to dry soil was 1.6 x 10 -4 while the CR values of the stem/leaf to dry soil fraction was 3.6 x 10 -3 . The Cr values for the pea seed, stem/pod and leaf components were 5.4 x 10 -4 , 3.3 x 10 -3 and 1.7 x 10 -2 , respectively. This indicates that the CR values used in certain radiological dose-assessment models may be high by about a factor of 100 when evaluating the consumption of seeds of legumes or cereal grains by man. (author)

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

    International Nuclear Information System (INIS)

    Rosa, Mychelle M.L.; Taddei, Maria Helena T.; Silva, Marco A.; Ferreira, Marcelo T.

    2011-01-01

    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 232 Th, 228 Th, and 228 Ra radionuclides in wild mushrooms collected at different locations in the plateau region. 228 Ra was determined by radiochemical separation using sulphate coprecipitation followed by beta radiometry. 232 Th and 228 Th were determined using anion exchange resin purification followed by alpha spectrometry. Higher values were obtained to 228 Th than to 232 Th. This is due to higher 228 Ra mobility, which decays to 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. Measurements of isomeric yield ratios of fission products from proton-induced fission on natU and 232Th via direct ion counting

    Directory of Open Access Journals (Sweden)

    Rakopoulos Vasileios

    2017-01-01

    Full Text Available Independent isomeric yield ratios (IYR of 81Ge, 96Y, 97Y, 97Nb, 128Sn and 130Sn have been determined in the 25 MeV proton-induced fission of natU and 232Th. The measurements were performed at the Ion Guide Isotope Separator On-Line (IGISOL facility at the University of Jyväskylä. A direct ion counting measurement of the isomeric fission yield ratios was accomplished for the first time, registering the fission products in less than a second after their production. In addition, the IYRs of natU were measured by means of γ-spectroscopy in order to verify the consistency of the recently upgraded experimental setup. From the obtained results, indications of a dependence of the production rate on the fissioning system can be noticed. These data were compared with data available in the literature, whenever possible. Using the TALYS code and the experimentally obtained IYRs, we also deduced the average angular momentum of the fission fragments after scission.

  15. A Reassessment of U-Th and 14C Ages for Late-Glacial High-Frequency Hydrological Events at Searles Lake, California

    Science.gov (United States)

    Lin, J.C.; Broecker, W.S.; Hemming, S.R.; Hajdas, I.; Anderson, Robert F.; Smith, G.I.; Kelley, M.; Bonani, G.

    1998-01-01

    U-Th isochron ages of tufas formed on shorelines suggest that the last pluvial event in Lake Lahontan and Searles Lake was synchronous at about 16,500 cal yr B.P. (equivalent to a radiocarbon age of between 14,000 and 13,500 yr B.P.), whereas the timing of this pluvial event determined by radiocarbon dating is on the order of 1000 yr younger. The timing of seven distinct periods of near desiccation in Searles Lake during late-glacial time has been reinvestigated for U-Th age determination by mass spectrometry. U-Th dating of evaporite layers in the interbedded mud and salt unit called the Lower Salt in Searles Lake was hampered by the uncertainty in assessing the initial 230Th/232Th of the samples. The resulting ages, corrected by a conservative range of initial 230Th/ 232Th ratios, suggest close correlation of the abrupt changes recorded in Greenland ice cores (Dansgaard-Oeschger events) and wet-dry conditions in Searles Lake between 35,000 and 24,000 Cal yr B.P. ?? 1998 University of Washington.

  16. Field studies on the terrestrial behavior of actinide elements in East Tennessee

    International Nuclear Information System (INIS)

    Garten, C.T. Jr.; Bondietti, E.A.; Trabalka, J.R.; Walker, R.L.; Scott, T.G.

    1984-01-01

    Field studies on the comparative uptake of various actinide elements ( 232 Th, 233 U, 238 U, 239 Pu, 241 Am, and 244 Cm) by plants and animals inhabiting historically contaminated environments on the Oak Ridge National Laboratory (ORNL) reservation in East Tennessee are summarized. The present-day pattern of actinide element bioaccumulation from a flood plain site contaminated with Pu in 1944 is U > Th approx. Pu. Thus the environmentally dispersed 239 Pu exhibits a transfer from floodplain soil to biota comparable to that of indigenous 232 Th and less than that of the indigenous 238 U. This ranking agrees with the chemical extractability of U, Th, and Pu from soil, using either weak acids or strongly basic reagents. The pattern of actinide element uptake from the shoreline of a historically contaminated pond is Pu 238 U = 233 U. This ranking also agrees with the chemical extractability of Pu, Am, Cm, and U from shoreline sediment, using weak acids. Results from field studies at ORNL agree with what has been generally inferred about the relative food chain transfer of the actinides, based on laboratory studies and field studies at other sites in the United States. Because they share the same valence state, there are apparent strong similarities in soil sorption, plant uptake, and animal uptake between trivalent Am and Cm and between tetravalent Pu and Th. Available evidence suggests that knowledge of the behavior of naturally occurring 232 Th in the terrestrial food chain can be useful for predicting the long-term fate of environmentally dispersed 239 Pu, while data on 238 U might be used to place an upper limit on the expected long-term food chain transfer of all transuranic elements except Np. 33 references, 5 figures, 1 table

  17. Biogeochemical responses to late-winter storms in the Sargasso Sea, III—Estimates of export production using 234Th: 238U disequilibria and sediment traps

    Science.gov (United States)

    Maiti, Kanchan; Benitez-Nelson, Claudia R.; Lomas, Michael W.; Krause, Jeffrey W.

    2009-06-01

    Direct measurements of new production and carbon export in the subtropical North Atlantic Ocean appear to be too low when compared to geochemical-based estimates. It has been hypothesized that episodic inputs of new nutrients into surface water via the passage of mesoscale eddies or winter storms may resolve at least some of this discrepancy. Here, we investigated particulate organic carbon (POC), particulate organic nitrogen (PON), and biogenic silica (BSiO 2) export using a combination of water column 234Th: 238U disequilibria and free-floating sediment traps during and immediately following two weather systems encountered in February and March 2004. While these storms resulted in a 2-4-fold increase in mixed layer NO 3 inventories, total chlorophyll a and an increase in diatom biomass, the systems were dominated by generally low 234Th: 238U disequilibria, suggesting limited particle export. Several 234Th models were tested, with only those including non-steady state and vertical upwelling processes able to describe the observed 234Th activities. Although upwelling velocities were not measured directly in this study, the 234Th model suggests reasonable rates of 2.2-3.7 m d -1. Given the uncertainties associated with 234Th derived particle export rates and sediment traps, both were used to provide a range in sinking particle fluxes from the upper ocean during the study. 234Th particle fluxes were determined applying the more commonly used steady state, one-dimensional model with element/ 234Th ratios measured in sediment traps. Export fluxes at 200 m ranged from 1.91±0.20 to 4.92±1.22 mmol C m -2 d -1, 0.25±0.08 to 0.54±0.09 mmol N m -2 d -1, and 0.22±0.04 to 0.50±0.06 mmol Si m -2 d -1. POC export efficiencies (Primary Production/Export) were not significantly different from the annual average or from time periods without storms, although absolute POC fluxes were elevated by 1-11%. This increase was not sufficient, however, to resolve the discrepancy

  18. Vegetation-derived insights on the mobilization and potential transport of radionuclides from the Nopal I natural analog site, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Leslie, B.W.; Pickett, D.A.; Pearcy, E.C.

    1999-07-01

    The Nopal I uranium (U) deposit, Pena Blanca, Mexico is a source term and contaminant transport natural analog to the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. In an attempt to characterize the mobilization and potential transport of radionuclides in the unsaturated zone at the Nopal I deposit, vegetation growing on ore piles was analyzed for {sup 238}U, {sup 235}U, and {sup 232}Th decay-series isotopes. Specimens of Phacelia robusta growing on high-grade piles of U ore were collected and analyzed by alpha autoradiography, and by alpha and gamma spectrometry. Activities for U, thorium (Th), and radium (Ra) isotopes (Bq/kg dried plant) were 300, 1,000, and 7,000 for {sup 238}U, {sup 230}Th, and {sup 226}Ra, respectively. The {sup 226}Ra activities in these specimens are among the highest ever measured for plants; furthermore, the plant-to-soil {sup 226}Ra concentration ratio is higher than expected. These results demonstrate the large mobility and bio-availability of Ra in the Nopal I environment, and support previous indications of recent loss of {sup 226}Ra from the ore body. Comparison between the activities of {sup 238}U and {sup 232}Th decay-chain Th isotopes in the plants and in the ore substrate indicate that relative mobilization into pore solutions of {sup 228}Th > {sup 230}Th > {sup 232}Th, in a ratio of about 50--25:4:1, respectively. The similarity of the plant's {sup 234}U/{sup 238}U activity ratio ({approximately}1.2) to that of a caliche deposit that formed adjacent to the Nopal ore body around 54 ka suggests the {sup 234}U/{sup 238}U activity ratio of U released from the ore is approximately 1.2. The U and {sup 226}Ra isotope activities of the plants and ore substrate, and solubility considerations, are used to assess a source term model of the potential Yucca Mountain repository. These results suggest the use of a natural analog source term model in performance assessments may be non-conservative.

  19. Evaluation of natural radioactivity and radiological hazards caused by different marbles of India

    International Nuclear Information System (INIS)

    Ramasamy, V.; Ponnusamy, V.; Hemalatha, J.; Meenakshisundaram, V.; Gajendiran, V.

    2005-01-01

    The samples used in this study are of various coloured varieties of marbles collected from marble dealers. The specific activity concentration of 238 U, 232 Th and 40 K has been determined by gamma ray spectrometry. The materials showed concentrations of 238 U, 232 Th and 40 K which were found to be dramatically variable depending on mineral content and type of formation. Using FTIR and thin section analyses, quartz, feldspar, calcite and mafic minerals present in the samples have been determined quantitatively. From our experimental data, it can be seen that the geochemical parameters such as SiO 2 or mafic minerals or CaCO 3 may be considered to be an appropriate index to select the marbles of low radiological risk. The average specific activities of 40 K are found to be higher than 232 Th, 238 U. The ratio of Th/U was calculated and correlated. Assessment of radiological hazards was made by calculating radium equivalent activities, external and internal hazard indices which were found to vary from 30.92 to 54.45, 0.08 to 0.14 and 0.10 to 0.17 Bq/kg, respectively. The observed values are lower than the recommended limits. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Parami, Vangeline Kinilitan

    2008-04-15

    , with {sup 238}U showing the highest enhancement of 93.72 among the radionuclides. When normalized with {sup 40}K, {sup 238}U in Plant P FA sample also had the highest enrichment factor (EF). Except for Plant C samples, {sup 228}Ra, {sup 228}Th and {sup 40}K were about equallypartitioned between BA and FA samples; {sup 238}U had consistently higher partitioning in all FA samples than BA samples; {sup 226}Ra and {sup 232}Th 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 {sup 226}Ra with {sup 238}U (R{sup 2}=0.98), and {sup 228}Ra with {sup 232}Th (R{sup 2}=0.94). Correspondence between ICP-MS and HPGe results were generally high with slopes of 0.90 and zero intercept for both {sup 226}Ra vs {sup 238}U and {sup 228}Ra vs {sup 232}Th. Correlations between NIRS HPGe and PNRI HPGe were also very high for {sup 226}Ra (R{sup 2}=0.93) and {sup 228}Ra (R{sup 2}=0.91), and high for {sup 40}K (R{sup 2}=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 {sup 226}Ra, {sup 228}Ra, and {sup 40}K 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

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

    International Nuclear Information System (INIS)

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

    2001-05-01

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

  2. 238U photonuclear studies with 5-10 MeV photons

    International Nuclear Information System (INIS)

    Hawkes, N.P.

    1986-02-01

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

  3. U isotopes distribution in the Lower Rhone River and its implication on radionuclides disequilibrium within the decay series.

    Science.gov (United States)

    Zebracki, Mathilde; Cagnat, Xavier; Gairoard, Stéphanie; Cariou, Nicolas; Eyrolle-Boyer, Frédérique; Boulet, Béatrice; Antonelli, Christelle

    2017-11-01

    The large rivers are main pathways for the delivery of suspended sediments into coastal environments, affecting the biogeochemical fluxes and the ecosystem functioning. The radionuclides from 238 U and 232 Th-series can be used to understand the dynamic processes affecting both catchment soil erosion and sediment delivery to oceans. Based on annual water discharge the Rhone River represents the largest river of the Mediterranean Sea. The Rhone valley also represents the largest concentration in nuclear power plants in Europe. A radioactive disequilibrium between particulate 226 Ra (p) and 238 U (p) was observed in the suspended sediment discharged by the Lower Rhone River (Eyrolle et al. 2012), and a fraction of particulate 234 Th was shown to derive from dissolved 238 U (d) (Zebracki et al. 2013). This extensive study has investigated the dissolved U isotopes distribution in the Lower Rhone River and its implication on particulate radionuclides disequilibrium within the decay series. The suspended sediment and filtered river waters were collected at low and high water discharges. During the 4-months of the study, two flood events generated by the Rhone southern tributaries were monitored. In river waters, the total U (d) concentration and U isotopes distribution were obtained through Q-ICP-MS measurements. The Lower Rhone River has displayed non-conservative U-behavior, and the variations in U (d) concentration between southern tributaries were related to the differences in bedrock lithology. The artificially occurring 236 U was detected in the Rhone River at low water discharges, and was attributed to the liquid releases from nuclear industries located along the river. The ( 235 U/ 238 U) (d) activity ratio (=AR) in river waters was representative of the 235 U natural abundance on Earth. The ( 226 Ra/ 238 U) (p) AR in suspended sediment has indicated a radioactive disequilibrium (average 1.3 ± 0.1). The excess of 234 Th in suspended sediment =( 234 Th xs

  4. Cross-section activation measurement for U-238 through protons and deuterons in energy interval 10-14 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Guzhovskii, B.Y.; Abramovich, S.N.; Zvenigorodskii, A.G. [Russia Federal Nuclear Centre, Arzamas (Russian Federation)] [and others

    1995-10-01

    There were presented results of cross-section measurements for nuclear reactions {sup 238}U(p,n){sup 238}Np, {sup 238}U(d,2n){sup 238}Np, {sup 238}U(d,t){sup 237}U, {sup 238}U(d,p){sup 239}U, and {sup 238}U(d,n){sup 239}Np. Interval of projectile energy was 10-14 MeV. For measurements of cross-sections it was used the activatio methods. The registration of {beta}- and {gamma}-activity was made with using of plastic scintillation detector and Ge(Li)-detector.

  5. 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

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

    International Nuclear Information System (INIS)

    Feng, S.; Yang, Y.W.; Lu, X.X.; Liu, R.; Jiang, L.; Zhu, T.H.; Wang, M.; Qin, J.G.

    2015-01-01

    Highlights: • An integral experiment for 232 Th(n, 2n) reaction was carried out on the newly-established ThO 2 /depleted uranium cylinders. • 232 Th(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 232 Th(n, 2n) reaction. - Abstract: In order to verify the evaluated cross sections of 232 Th(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. 232 Th(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 232 Th(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 232 Th(n, 2n) reaction

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

    International Nuclear Information System (INIS)

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

    1984-05-01

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

  8. Novel use of disequilibrium ages in geothermal energy exploration

    International Nuclear Information System (INIS)

    Goles, G.G.; Seymour, R.S.

    1984-01-01

    Geothermal exploration commonly involves estimation of ages of young volcanic rocks. Few reliable techniques are available for this purpose, uranium-series disequilibrium being one. Several activity ratios may be used to estimate disequilibrium ages. Th-230/U-238 were used because of the convenient half-life of Th-230 and because excess Th-230 in volcanic rocks has been found and used to obtain reasonable ages. By analyzing mafic and felsic fractions of each rock studied, data were obtained to construct quasi-isochrons, assuming that minerals in each fraction had the same initial Th-230/Th-232 activity ratio. Analyses were done via epithermal instrumental activation analysis (Th-232, and U-238) and alpha spectrometry (Th-230 and Th-232), an approach that is simple, rapid and allows explicit estimation of chemical yields. Four rocks from the Oregon High Cascades yielded ages or a limit on age consistent with known geological relations. Several improvements in the method could be implemented without serious impact on its simplicity. 15 references, 1 figure, 1 table

  9. Gamma-spectrometric measurement of radioactivity in agricultural soils of the Lombardia region, northern Italy

    International Nuclear Information System (INIS)

    Guidotti, Laura; Carini, Franca; Rossi, Riccardo; Gatti, Marina; Cenci, Roberto M.; Beone, Gian Maria

    2015-01-01

    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 238 U, 232 Th, 137 Cs and 40 K by measuring soil samples by gamma spectrometry. 238 U, 232 Th and 40 K activities range 24–231, 20–70, and 242–1434 Bq kg −1 respectively. The geographic distribution of 238 U 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 238 U than of 232 Th. The 238 U activities become lower than 232 Th when soils are located in the plain, originating from basic sedimentary rocks. 137 Cs activity ranges 0.4–86.8 kBq m −2 . The lowest activity of 137 Cs is in the plain, whereas the highest is in the North on soils kept as lawn or pasture. The 137 Cs activity of some samples suggests the presence of accumulation processes that lead to 137 Cs 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

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

    International Nuclear Information System (INIS)

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

    1983-06-01

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

  12. Study on the formation of fission isomer via 232Th + α reaction

    International Nuclear Information System (INIS)

    Vianna, D.M.

    1982-01-01

    The formation of fission isomer through 232 Th+α reaction is studied using the distance-recoil method, employing policarbonate MAKROFOL detector. The total isomeric half-life measured has the value T 1/2 = 0.23 ± 0.03 ns and an ratio of formation of isomeric fission relative to prompt fission(σ i /σ p =0.75x10 -5 ). According to the energy of incident particle (Eα = 28 MeV), the cross-sections presented in the literature and the low value found for the total isomeric half-life, we attribute these half-life value to the 234 U isomer (even-even nucleus). The results were compared with those existent in the literature (La69, E170, Re70, Wo70, Po70, Br71) for this isomer. (author) [pt

  13. Contribution to study of effects consecutive to alpha decay of uranium 238 in some uranium compounds and uranium ores

    International Nuclear Information System (INIS)

    Ordonez-Regil, E.

    1985-06-01

    The consequences of alpha decay of 238 U in uranium compounds and in uranium bearing ores have been examined in two ways: leaching of 234 Th and determination of the activity ratio of 234 U and 238 U. The results have been interpreted mainly in terms of the ''hot'' character of the nascent 234 Th atoms [fr

  14. Natural Radiation in byproducts of the production of phosphoric acid

    International Nuclear Information System (INIS)

    Silveira, Marcilei A. Guazzelli da; Cardoso, L.L.; Medina, N.H.

    2014-01-01

    Natural radiation is the largest source of radiation exposure to which man is subject. It is formed basically by cosmic radiation and the radionuclides present in the Earth crust, as 40 K and the elements of the decay series of 232 Th and 238 U. Phosphate ores, which constitutes the raw material for the production of phosphoric acid, have a high rate of natural radiation from the decay series of 232 Th and 238 U. Phosphogypsum, which is naturally radioactivity, is a by-product of the production of phosphoric acid by the wet method. For each ton of phosphoric acid it is produced about 4.5 tons of phosphogypsum. This work presents the analysis of samples collected in all stages of the manufacturing process of phosphoric acid, which generates the phosphogypsum. Gamma-ray spectrometry was used to measure the concentration of the elements of the decay series of 232 Th and 238 U. All analyzed samples showed a high concentration of radionuclides, promoting the need for further steps in the process in order to reduce the presence of such radionuclides in the phosphogypsum. The results indicate the radionuclide 238 U has higher contribution in some samples of the intermediate stages of the process. All samples exceeded the international average range of human exposure to terrestrial gamma radiation, which is 0.3 to 1.0 mSv/year. (author)

  15. Natural radioactivity determination in samples of Peperomia pellucida commonly used as medicinal herb

    International Nuclear Information System (INIS)

    Sussa, Fabio V.; Silva, Paulo S.C.; Damatto, Sandra R.; Alencar, Marcos M.; Mazzilli, Barbara P.

    2011-01-01

    The radionuclide concentration in different environmental matrixes is reported in literature; however, studies of the distribution of 238 U and 232 Th decay products in plant species are sparse. In this study concentration of naturally occurring radionuclides 238 U, 234 U, 232 Th, 230 Th, 226 Ra, 228 Ra and 210 Pb was determined in sample of Peperomia pellucida and in the surrounding soil. Peperomia pellucida has a rich history of medicinal uses. The content of U and Th isotopes in the leaves, aerial parts, roots and soil was determined by alpha spectrometry after with radiochemical separation by ionic exchange resins and measurement with a silicon surface-barrier detector. The radionuclides measurement of 226 Ra, 228 Ra and 210 Pb were carried out by gross alpha and beta counting after radiochemical separation. The radionuclide activity concentrations mean in samples analyzed ranged from 4.3 to 38 Bq kg -1 for 238 U, from 42 to 129 Bq kg -1 for 234 U, from 2.1 to 38 Bq kg -1 for 230 Th, from 1.7 to 124 Bq kg -1 for 232 Th, from 8.5 to 37 Bq kg -1 for 226 Ra, from 3.2 to 46 Bq kg -1 for 228 Ra, from 39 to 93 Bq kg -1 for 210 Pb. It was also determined the percentage of radionuclides 226 Ra, 228 Ra and 210 Pb in the extraction and infusion of the drug analyzed. The arithmetical mean value recovery was from 23% to 60% in maceration and 24% to 75% in infusion. (author)

  16. Evaluation and compilation of fission product yields 1993

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  17. Evaluation and compilation of fission product yields 1993

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-31

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

  18. Natural radioactivity of beach sand samples in Port Sudan, red sea state

    International Nuclear Information System (INIS)

    Kambal, Wala Haider Hussein

    2015-01-01

    Natural radioactivity is a source of continuous exposure to human beings. In Port Sudan city, the main port of Sudan, data on the levels of natural radioactivity in soil is required. The aim of this study was to measure the activity concentration as well as the absorbed dose and annual effective dose of the naturally occurring radionuclides 238 U, 232 Th, and 40 K in soil samples collected from different locations around Red Sea costa areas in Port Sudan city. Activity concentrations were measured using gamma ray spectrometry (Nal) detector. Results showed that the average activity concentration of 238 U, 232 Th and 40 K were found to be 21.86, 17.55, 85.50 Bqkg 1 , respectively, with an average absorbed dose of 10.42, 9.40 and 3.57 nGyh 1 , respectively. The average annual effective dose values were found to be 11.89, 11.54 and 4.37 μSvy 1 for 238 U, 232 Th and 40 K, respectively. The measured values were comparable with other global radioactivity measurements and found to be safe for public and environment.(Author)

  19. Radiometric Characterization of Sand in Northeast Sinai

    International Nuclear Information System (INIS)

    Ramadan, Kh.A.; Badran, H.M.; Ramadan, Kh.A.; Seddeek, M.K.; Sharshar, T.

    2009-01-01

    Thirty-eight locations covering an area of 350 km 2 in northeast Sinai were investigated by gamma-ray spectroscopy using a 50% HPGe detector. The limits of area are Al-Arish North, El-Hasana South, El-Oga East, and El- Gifgafa West. The range of activity concentrations of 238 U, 234 Th, 226 Ra, 232 Th and 40 K are 0.6-35.2, 3.9-22.6, 4.7-29.6, 4.7-23.9, and 108-295 Bq/kg for sands, respectively. 137 Cs in the region ranged from 0.1-8.0 Bq/kg. No major difference between the studied area and that previously investigated in the costal area in North Sinai. Reliable correlations (R2 = 0.8-0.9) among 238 U, 234 Th, and 226 Ra isotopes was obtained. On the other hand, low correlation (R 2 = 0.6-0.7) was obtained from the analysis of the isotopes of 238 U-seies and 232 Th. No evidence of correlation between the concentrations of radioisotopes and pH contents, TOM, and grain size were found. The soil-plant transfer factor are 226 Ra and 232 Th, 40 K, and 137 Cs, respectively. The wild vegetations collected from the studied area have average concentrations of 1.9, 1.4, 1.3, 254, and 0.3 for 234 Th, 226 Ra, 232 Th, 40 K, and 137 Cs, respectively. The average concentrations of 226 Ra, 232 Th, and 40 K in water samples collected from five wells are 0.02, 0.02, and 1.1 Bq/l, respectively. The average absorbed dose rate for the sand samples were calculated to be 19.4 n Gy h-1. The Raeq activities of the sands are lower than the recommended maximum value of 370 Bq kg-1 criterion limit of Raeq activity for building materials

  20. Activation Doppler Measurements on U 238 and U 235 in Some Fast Reactor Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Tiren, L I; Gustafsson, I

    1968-03-15

    Measurements of the Doppler effect in U-238 capture and U-235 fission have been made by means of the activation technique in three different neutron spectra in the fast critical assembly FR0. The experiments involved the irradiation of thin uranium metal foils or oxide disks, which were heated in a small oven located at the core centre. The measurements on U-238 were extended to 1780 deg K and on U-235 to 1470 deg K. A core region surrounding the oven was homogenized in order to facilitate the interpretation of results. The reaction rates in the uranium samples were detected by gamma counting. The experimental method was checked with regard to systematic errors by irradiations in a thermal spectrum. The data obtained for U-238 capture were corrected for the effect of neutron collisions in the oven wall, and were extrapolated to zero sample thickness. In the softest spectrum (core 5) a Doppler effect (relative increase in capture rate) of 0.260 {+-} 0.018 was obtained on heating from 343 to 1780 deg K, and in the hardest spectrum (core 3) the corresponding value was 0.030 {+-} 0.003. An appreciable Doppler effect in U-235 fission was obtained only in the softest spectrum, in which the measured increase in fission rate on heating from 320 to 1470 deg K was 0.007 {+-} 0.003.

  1. Assessment of radiological significance of naturally occurring radionuclides in soil and rock matrices around Kakrapar environment

    International Nuclear Information System (INIS)

    Patra, A.K.; Jaison, T.J.; Baburajan, A.; Hegde, A.G.

    2008-01-01

    The activity and gamma-absorbed dose rate due to the naturally occurring radionuclides in the terrestrial environment such as 238 U, 232 Th and 40 K were determined in soil and rock samples collected around Kakrapar Atomic Power Plant site, using gamma-ray spectrometry. The mean concentration levels measured in Kakrapar soil from naturally occurring radioisotopes such as 238 U, 232 Th and 40 K are lower than the corresponding global average values obtained in worldwide soil. The external hazard index (Hex) and absorbed gamma dose rate in air outdoors is observed to be 0.04-0.18 and 3.1-14.1 nGy h -1 , respectively. (authors)

  2. Glaciation control of melting rates in the mantle: U-Th systematics of young basalts from Southern Siberia and Central Mongolia

    Science.gov (United States)

    Rasskazov, S.; Chebykin, E.

    2012-04-01

    Eastern Sayans, Siberia and Hangay, Central Mongolia are mountainous uplifts effected by Quaternary volcanism, but only the former area was covered by glaciers that were as thick as 500 m. Glaciation time intervals were marked by moraines and sub-glacial hyaloclastite-bearing volcanic edifices, whereas interglacial ones were exhibited by sub-aerial "valley" flows and cinder cones. To estimate temporal variations of maximum rates of melting and mantle upwelling in the glacial and glacial-free areas, we measured radionuclides of the U-Th system for 74 samples of the Middle-Late Pleistocene through Holocene basalts by ICP-MS technique (Chebykin et al. Russian Geol. Geophys. 2004. 45: 539-556) using mass-spectrometer Agilent 7500ce. The obtained U-Th isochron ages for the Pleistocene volcanic units in the age interval of the last 400 Kyr are mostly consistent with results of K-Ar dating. The measured (230Th/238U) ratios for the Holocene basalts from both areas are within the same range of 1.08-1.16 (parentheses denote units of activity), whereas the 50 Kyr lavas yield, respectively, the higher and lower initial (230Th0/238U) ratios (1.18-1.46 and 1.05-1.13). This discrepancy demonstrates contrast maximum rates of melting in conventional garnet peridotite sources. We suggest that this dynamical feature was provided by the abrupt Late Pleistocene deglaciation that caused the mantle decompression expressed by the earlier increasing melting beneath Eastern Sayans than beneath Hangay. In the last 400 Kyr, magmatic liquids from both Eastern Sayans and Hangay showed the overall temporal decreasing (230Th0/238U) (i.e. relative increasing rates of melting and upwelling of the mantle) with the systematically lower isotopic ratios (i.e. increased mantle activity) in the former area than in the latter. The 400 Kyr phonotephrites in Hangay showed elevated concentrations of Th (6-8 ppm) and Th/U (3.7-3.9). The high (230Th0/238U) (4.3-6.0) reflected slow fractional melting

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

    Science.gov (United States)

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

    2017-09-01

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

  4. The 230Th correction is the 1st priority for accurate dates of young zircons: U/Th partitioning experiments and measurements

    Science.gov (United States)

    Krawczynski, M.; McLean, N.

    2017-12-01

    One of the most accurate and useful ways of determining the age of rocks that formed more than about 500,000 years ago is uranium-lead (U-Pb) geochronology. Earth scientists use U-Pb geochronology to put together the geologic history of entire regions and of specific events, like the mass extinction of all non-avian dinosaurs about 66 million years ago or the catastrophic eruptions of supervolcanoes like the one currently centered at Yellowstone. The mineral zircon is often utilized because it is abundant, durable, and readily incorporates uranium into its crystal structure. But it excludes thorium, whose isotope 230Th is part of the naturally occurring isotopic decay chain from 238U to 206Pb. Calculating a date from the relative abundances of 206Pb and 238U therefore requires a correction for the missing 230Th. Existing experimental and observational constraints on the way U and Th behave when zircon crystallizes from a melt are not known precisely enough, and thus currently the uncertainty in dates introduced by they `Th correction' is one of the largest sources of systematic error in determining dates. Here we present preliminary results on our study of actinide partitioning between zircon and melt. Experiments have been conducted to grow zircon from melts doped with U and Th that mimic natural magmas at a range of temperatures, and compositions. Synthetic zircons are separated from their coexisting glass and using high precision and high-spatial-resolution techniques, the abundance and distribution of U and Th in each phase is determined. These preliminary experiments are the beginning of a study that will result in precise determination of the zircon/melt uranium and thorium partition coefficients under a wide variety of naturally occurring conditions. This data will be fit to a multidimensional surface using maximum likelihood regression techniques, so that the ratio of partition coefficients can be calculated for any set of known parameters. The results of

  5. Intercomparison of radionuclide measurements in marine sediment sample IAEA-368

    International Nuclear Information System (INIS)

    Ballestra, S.; Lopez, J.J.; Gastaud, J.; Parsi, P.; Vas, D.; Noshkin, V.

    1991-08-01

    The results of an intercomparison exercise on a Pacific Ocean sediment sample, IAEA-368, designed for the determination of artificial and natural radionuclides levels, are reported. The data from 89 laboratories representing 37 countries have been evaluated. The following are the recommended values, with confidence intervals, for 60 Co, 155 Eu, 210 7Pb, 226 Ra, 238 U, 238 Pu and 239+240 Pu (Reference date: 1 January 1990). Information values for 40 K, 90 Sr, 137 Cs, 228 Th, 230 Th, 232 Th, 234 U, 235 U and 241 Am are also reported. (author)

  6. 232Th Mass Determination in a Uranium/Thorium Mixture for Safeguards Purposes

    International Nuclear Information System (INIS)

    Nangu, M.; Marumo, B.; Mbedzi, E.; Rasweswe, M.; Croft, S.; McElroy, R.; Chapman, J.; Bosko, A.

    2015-01-01

    In nuclear safeguards it is required that thorium content in safeguarded material should be quantified and reported as appropriate. As such the South African State System of Control and Accounting (SSAC) on discovering a number of safeguarded waste drums which contained considerable quantities of thorium decided to initiate a project to properly quantify their thorium content using a high purity germanium detector and In Situ Object Counting System (ISOCS) efficiency calibration software. These metal waste drums are contained inside overpacks which for health reasons cannot be opened and thus giving rise to the challenge of determining the exact fill heights and the density of the material. Fill heights determined using transmission sources and the material density calculated from them together with the geometry used for the overpacks could be used to further refine the ISOCS calibration geometry and thus improving the quantitative result. In order to have confidence on the ISOCS measurements, it was decided to also validate the ISOCS results through the preparation of similar density standards that would be used for the efficiency calibration in the determination of the 232Th activity in the material. In addition, MGAU v4.2, which was used to determine uranium enrichment in a measured material, also provides an approximate 232Th abundance relative to uranium content. ISOCS measurements of 232Th masses in waste drums were compared to MGAU results. Results of these studies are presented in this paper. (author)

  7. Inclusive quasifree electrofission cross section for 238U

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  8. Isotopic composition of Pb and Th in interplinian volcanics from Somma-Vesuvius volcano, Italy

    International Nuclear Information System (INIS)

    Cortini, M.; De Vivo, B.; Somma, R.; Ayuso, R.A.; Holden, P.

    2004-01-01

    We present a detailed isotopic study of volcanic rocks emitted from Somma-Vesuvius volcano during three periods of interplinian activity: 'Protohistoric' (3550 y B.P. to 79 A.D.), 'Ancient Historic' (79 to 472 A.D.) and 'Medieval' (472 to 1631 A.D.). Pb isotopic compositions of two acid leached fractions and whole rock residues of 37 whole rock samples (determined by Somma et al., 2001) show that each of the three interplinian periods is distinguished by small, systematic, and unique uranogenic and thorogenic Pb isotopic trends. This key and novel feature is compatible with the notion that the Pb isotopic data reflect small-scale source heterogeneity operating over relatively short periods of time. From this representative group of samples, a selected set of nine whole rocks were analyzed for Th isotopes. 232 Th/ 238 U ratios in the source can be obtained independently from Pb and from Th isotopes. Those obtained from Pb isotopes represent source ratios, time-integrated over the whole age of the earth; they range from 3.9 to 4.1. 232 Th/ 238 U obtained from Th isotopes are those of the present source. They are lower, and cluster around 3.5; this difference probably indicates recent U enrichment of the present source. The behavior of Pb, as inferred by its isotopic ratios, is quite distinct from that of Sr and Nd isotopes: Pb isotope variations are not correlated to Sr or Nd isotope variations. The isotopic contrast is compatible with the idea that the isotopes were decoupled during magmatic production, evolution, and ascent through the crust. Thus, the Pb isotopes do not reflect the effects of the same processes as in the case of the Sr and Nd isotopes, or, as we also favor, they do not necessarily reflect the same source contributions into the magmas. Moreover, the Pb isotopic evolution of the interplinian rocks chiefly reflects mixing, driven by processes that are superimposed on, and independent of, other source contributions that determine the isotopic

  9. Mass distribution in 20Ne+232Th reaction

    International Nuclear Information System (INIS)

    Sodaye, Suparna; Tripathi, R.; Sudarshan, K.

    2011-01-01

    Mass distribution was measured in 20 Ne+ 232 Th reaction at E lab =145 MeV using recoil catcher technique followed by off-line gamma-ray spectrometry. Significant contribution from transfer fission was observed in the yield of comparatively neutron rich fission products. The variance of mass distribution for complete fusion fission, obtained by excluding neutron rich fission products, was observed to be consistent with the values reported in literature for similar reaction systems which showed a deviation from the systematics obtained using random neck rupture and liquid drop model. (author)

  10. Uptake and distribution of /sup 232/U in peas and barley

    Energy Technology Data Exchange (ETDEWEB)

    Schreckhise, R G; Cline, J F [Battelle Pacific Northwest Labs., Richland, WA (USA)

    1980-03-01

    The uptake of /sup 232/U from soil and its distribution in peas and barley were examined under conditions which isolated root uptake from deposition on aboveground plant parts. Aboveground plant parts were harvested at maturity and analyzed for /sup 232/U content by alpha-energy-analysis. The ratio of concentration (CR) of /sup 232/U in the dry barley seeds to dry soil was 1.6 x 10/sup -4/ while the CR values of the stem/leaf to dry soil fraction was 3.6 x 10/sup -3/. The Cr values for the pea seed, stem/pod and leaf components were 5.4 x 10/sup -4/, 3.3 x 10/sup -3/ and 1.7 x 10/sup -2/, respectively. This indicates that the CR values used in certain radiological dose-assessment models may be high by about a factor of 100 when evaluating the consumption of seeds of legumes or cereal grains by man.

  11. The U238 antineutrino spectrum in the Double Chooz experiment

    Energy Technology Data Exchange (ETDEWEB)

    Haag, Nils; Oberauer, Lothar; Potzel, Walter; Schreckenbach, Klaus [Technische Universitaet, Muenchen (Germany); Lachenmaier, Tobias [Eberhard Karls Universitaet, Tuebingen (Germany)

    2011-07-01

    The DoubleChooz experiment aims at the determination of the unknown neutrino mixing parameter {Theta}{sub 13}. Two liquid scintillator detectors will measure an electron antineutrino disappearance at the Chooz site in the French ardennes. In order to improve the sensitivity, the antineutrino spectrum emitted by the Chooz reactor cores has to be determined with high accuracy. This talk focusses on the U238 spectrum, which is the only contributing spectrum, that was not measured until now. The final U238 beta spectrum is presented, and its implementation into the analysis framework is shown.

  12. 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.

  13. Ecological transfer of radionuclides and metals to free-living earthworm species in natural habitats rich in NORM.

    Science.gov (United States)

    Mrdakovic Popic, Jelena; Salbu, Brit; Skipperud, Lindis

    2012-01-01

    Transfer of radionuclides ((232)Th and (238)U) and associated metals (As, Cd, Pb and Cr) from soil to free-living earthworm species was investigated in a thorium ((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 (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 ((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 (232)Th and (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 μGy/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 (232)Th and (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 radionuclides and metals and to assessment

  14. Determination of Pu and U by ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Muramatsu, Y.; Yoshida, S. [National Inst. of Radiological Sciences, Chiba (Japan)

    2002-06-01

    In order to understand the distribution and behaviour of long-lived radionuclides in the terrestrial environment, we have developed analytical methods for {sup 238}U, {sup 232}Th and {sup 239},{sup 240}Pu and determined them in several environmental samples. ICP-MS was applied to the analyses. Concentrations of {sup 238}U and {sup 232}Th were determined in variety of soils, plants and environmental waters. The mean concentration of U and Th in 77 soils, collected several parts of Japan, were 2.3 and 7.0 ppm (dry wt). Red and yellow soils, which are mainly found in western Japan, have high concentrations of Th, suggesting the contribution from granitic rocks. Higher concentration of U in agricultural soils than forest soils suggested the possible accumulation of this element from phosphate fertilizer. The soil-to-plant transfer factors (concentration ratios between plants and soils) of U and Th were estimated from the analytical results of these nuclides in soils and in several crops. The factors for U were about 0.0005 in leaf vegetables, 0.0002 in root vegetables, 0.0001 in potatoes and 0.00001 in rice (polished). For Th, the factors were about 0.0005 in leaf vegetables, 0.0008 in root vegetables, 0.0005 in potatoes and 0.00003 in rice (polished). For the analysis of plutonium, chromatographic resin, Dowex 1x8, was examined for their applicability in the separation of Pu from the matrix elements. Sufficient decontamination factors (10{sup 4}-10{sup 5}) for many matrix elements including U, which interferes in the detection of mass 239, were obtained in both resins. Analytical results of {sup 239+240}Pu in standard reference materials (IAEA-135, -SOIL-6, -368 and -134) indicated that the accuracy of this method was satisfactory. Data on the {sup 240}Pu/{sup 239}Pu atom ratios in these reference materials, which are rare in the literature, were also obtained. Soil samples from the Marshall Islands showed a large variation of the {sup 240}Pu/{sup 239}Pu atom ratios

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

    CSIR Research Space (South Africa)

    Kronfeld, J

    1994-05-01

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

  16. Limits on uranium and thorium bulk content in GERDA Phase I detectors

    Science.gov (United States)

    GERDA Collaboration; Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Becerici-Schmidt, N.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; di Vacri, A.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Fedorova, O.; Freund, K.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakemüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schütz, A.-K.; Schulz, O.; Schwingenheuer, B.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Stepaniuk, M.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Walter, M.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2017-05-01

    Internal contaminations of 238U, 235U and 232Th in the bulk of high purity germanium detectors are potential backgrounds for experiments searching for neutrinoless double beta decay of 76Ge. The data from GERDA Phase I have been analyzed for alpha events from the decay chain of these contaminations by looking for full decay chains and for time correlations between successive decays in the same detector. No candidate events for a full chain have been found. Upper limits on the activities in the range of a few nBq/kg for 226Ra, 227Ac and 228Th, the long-lived daughter nuclides of 238U, 235U and 232Th, respectively, have been derived. With these upper limits a background index in the energy region of interest from 226Ra and 228Th contamination is estimated which satisfies the prerequisites of a future ton scale germanium double beta decay experiment.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

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

    International Nuclear Information System (INIS)

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

    1989-01-01

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

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

    Science.gov (United States)

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

    2017-01-01

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

  20. Gamma-spectrometric measurement of radioactivity in agricultural soils of the Lombardia region, northern Italy.

    Science.gov (United States)

    Guidotti, Laura; Carini, Franca; Rossi, Riccardo; Gatti, Marina; Cenci, Roberto M; Beone, Gian Maria

    2015-04-01

    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 (238)U, (232)Th, (137)Cs and (40)K by measuring soil samples by gamma spectrometry. (238)U, (232)Th and (40)K activities range 24-231, 20-70, and 242-1434 Bq kg(-1) respectively. The geographic distribution of (238)U 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 (238)U than of (232)Th. The (238)U activities become lower than (232)Th when soils are located in the plain, originating from basic sedimentary rocks. (137)Cs activity ranges 0.4-86.8 kBq m(-2). The lowest activity of (137)Cs is in the plain, whereas the highest is in the North on soils kept as lawn or pasture. The (137)Cs activity of some samples suggests the presence of accumulation processes that lead to (137)Cs 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. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

    International Nuclear Information System (INIS)

    Misulovin, A.

    1978-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-09-01

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

  3. Features of the neutron spectra accompanying the fission of actinide nuclei

    International Nuclear Information System (INIS)

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

    2000-01-01

    The spectra of fission neutrons from 238 U are measured by the time-of-flight technique at incident-neutron energies E n = 5.0 and 13.2 MeV. The data are compared with those obtained in the previous studies for 232 Th, 235,238 U, 237 Np at E n = 2.9 and 14.7 MeV; for 232 Th at E n = 14.6 and 17.7 MeV; for 238 U at 16.0 and 17.7 MeV. An excess of soft neutrons, which is observed in comparing experimental spectra for E n 13.2, 14.7, 16.0 and 17.7 MeV with the results of traditional theoretical calculations, is reproduced fairly well under the assumption that, at high excitation energies of a compound system, some part of post-fission neutrons can be emitted by nonaccelerated fragments [ru

  4. A semi-empirical approach to analyze the activities of cylindrical radioactive samples using gamma energies from 185 to 1764 keV.

    Science.gov (United States)

    Huy, Ngo Quang; Binh, Do Quang

    2014-12-01

    This work suggests a method for determining the activities of cylindrical radioactive samples. The self-attenuation factor was applied for providing the self-absorption correction of gamma rays in the sample material. The experimental measurement of a (238)U reference sample and the calculation using the MCNP5 code allow obtaining the semi-empirical formulae of detecting efficiencies for the gamma energies ranged from 185 to 1764keV. These formulae were used to determine the activities of the (238)U, (226)Ra, (232)Th, (137)Cs and (40)K nuclides in the IAEA RGU-1, IAEA-434, IAEA RGTh-1, IAEA-152 and IAEA RGK-1 radioactive standards. The coincidence summing corrections for gamma rays in the (238)U and (232)Th series were applied. The activities obtained in this work were in good agreement with the reference values. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Alpha spectrometry Analysis of radioisotopes of thorium and uranium in the soil (IAEA soil reference ground 375 and the natural region of Utique (Bizerte))

    International Nuclear Information System (INIS)

    Mejri, Mouna

    2008-01-01

    Since the formation of the terrestrial crust, the primordial radionuclides are present in the minerals. The main are the radioactive elemnts of the Uranium 238, of Uranium 235, of the Thorium 232 chains, Potassium 40 and the Ribidium 87. In this survey, we will present the methodology of analysis of the natural radioisotopes of uranium ( 238 U, 235 U and 234 U) and those of the thorium ( 232 Th, 230 Th and 228 Th) presents to the state of tracers in the natural soils. The method of measurement used is the alpha spectrometry. This technique is very important in the radiometric analysis, especially for the pure alpha emitters or for the low levels of radioactivity analysis. The results if analysis of the Thorium are compared to those gotten by the ICP - AES ( t he Atomic Emission Spectrometry Coupled to an inductive Plasma ) . (Author)

  6. Distribution of natural and artificial radioactivity in soils, water and tuber crops.

    Science.gov (United States)

    Darko, Godfred; Faanu, Augustine; Akoto, Osei; Acheampong, Akwasi; Goode, Eric Jude; Gyamfi, Opoku

    2015-06-01

    Activity concentrations of radionuclides in water, soil and tuber crops of a major food-producing area in Ghana were investigated. The average gross alpha and beta activities were 0.021 and 0.094 Bq/L, respectively, and are below the guidelines for drinking water and therefore not expected to pose any significant health risk. The average annual effective dose due to ingestion of radionuclide in water ranged from 20.08 to 53.45 μSv/year. The average activity concentration of (238)U, (232)Th, (40)K and (137)Cs in the soil from different farmlands in the study area was 23.19, 31.10, 143.78 and 2.88 Bq/kg, respectively, which is lower than world averages. The determined absorbed dose rate for the farmlands ranged from 23.63 to 50.51 nGy/year, which is within worldwide range of 18 to 93 nGy/year. The activity concentration of (238)U, (232)Th, (40)K and (137)Cs in cassava ranges from 0.38 to 6.73, 1.82 to 10.32, 17.65 to 41.01 and 0.38 to 1.02 Bq/kg, respectively. Additionally, the activity concentration of (238)U, (232)Th, (40)K and (137)Cs in yam also ranges from 0.47 to 4.89, 0.93 to 5.03, 14.19 to 35.07 and 0.34 to 0.89 Bq/kg, respectively. The average concentration ratio for (238)U, (232)Th and (40)K in yam was 0.12, 0.11 and 0.17, respectively, and in cassava was 0.11, 0.12 and 0.2, respectively. None of the radioactivity is expected to cause significant health problems to human beings.

  7. Investigation of natural radionuclide contents in soil in China

    International Nuclear Information System (INIS)

    Pan Sanming; Liu Ruye

    1992-01-01

    The survey of natural radionuclide contents in soil in China (1983-1990) is a part of investigation of environmental natural radioactivity level on China. The results of the investigation area as follows: (1) The average content of natural radionuclides 238 U, 226 Ra, 232 Th and 40 K(area weighted) and its standard deviation for single measurement is 39.5 and 34.4,36.5 and 22.0, 49.1 and 27.6, 580.0 and 202.0 Bq.kg -1 ,respectively.(2) The content of natural radionuclides is apparently correlated to the types of soil-forming rock. The analysis results from 1552 soil samples of soil-forming rock show that: the content of 238 U, 226 Ra, 232 Th and 40 K for magmatic rock type is the highest, 238 U, 226 Ra and 232 Th of metamorphic rock type higher, sedimentary rock type the lowest. However, the content of 40 K of sedimentary rock type is more higher, magmatic rock type the lowest. In magmatic rock type, the content of 238 U, 226 Ra, 232 Th of granite and acidic magmatic rock type, and the content of 40 K of acidic and alkaline magmatic rock type are higher. (3) The analysis results from 9613 various types of soil samples show that for crimson soil of ferralsol wind soil of rock soil-forming order at northern part is lower. For frigid dessert soil of alpine soil order, alpine dessert soil, and the burozem, dark burozem and drab soil of alfisol order and semialfisol order, the content of 40 K is shown to be higher, and it is lower for latosol of ferralsol order, crimson soil, yellow soil and various lime soil. (4) The geographical distribution of the natural radionuclide content in soil appears apparently regional

  8. 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)

  9. Evaluation of metal and radionuclide data from neutron activation and acid-digestion-based spectrometry analyses of background soils: Significance in environmental restoration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.Y.; Watkins, D.R.; Jackson, B.L.; Schmoyer, R.L. [Oak Ridge National Lab., TN (United States); Lietzke, D.A.; Burgoa, B.B.; Branson, J.T.; Ammons, J.T. [Univ. of Tennessee, Knoxville, TN (United States)

    1995-12-31

    A faster, more cost-effective, and higher-quality data acquisition procedure for natural background-level metals and radionuclides in soils is needed for remedial investigations of contaminated sites. In this project, a total of 120 soil samples were collected from uncontaminated areas on and near the Oak Ridge Reservation. The samples were taken at three different depths and from three different geologic groups to establish background concentrations of metals and radionuclides. The objective of this presentation is to discuss the advantages and disadvantages of neutron activation analysis (NAA) compared with those of acid-digestion-based spectrometry (ADS) methods; the advantages and disadvantages were evaluated from Al, Sb, As, Cr, Co, Fe, Mg, Mn, Hg, K, Ag, {sup 232}Th, {sup 235}U, {sup 238}U, V, and Zn data. The ADS methods used for this project were inductively coupled plasma (ICP), ICP-mass spectrometry (ICP-MS), and alpha spectrometry. The scatter plots showed that the NAA results for As, Co, Fe, Mn, {sup 232}Th, and {sup 238}U are reasonably correlated with the results from the other analytical methods. Compared to NAA, however, the ADS methods underestimated Al, Cr, Mg, K, V, and Zn. The skew distributions were caused by incomplete dissolution of the analytes during acid digestion of the soil samples. Because of the high detection limits of the spectrometric methods, the NAA results and the ADS results for some elements, including Sb, Hg, and Ag, did not show a definite relationship. The NAA results were highly correlated with the alpha spectrometry results for {sup 232}Th and {sup 238}U but poorly correlated for {sup 235}U, probably because of a larger counting error associated with the lower activity of the isotope. The NAA methods, including the delayed neutron counting method, were far superior techniques for quantifying background levels of radionuclides ({sup 232}Th, {sup 235}U, and {sup 238}U) and metals (Al, Cr, Mg, K, V, and Zn) in soils.

  10. Evaluation of metal and radionuclide data from neutron activation and acid-digestion-based spectrometry analyses of background soils: Significance in environmental restoration

    International Nuclear Information System (INIS)

    Lee, S.Y.; Watkins, D.R.; Jackson, B.L.; Schmoyer, R.L.; Lietzke, D.A.; Burgoa, B.B.; Branson, J.T.; Ammons, J.T.

    1995-01-01

    A faster, more cost-effective, and higher-quality data acquisition procedure for natural background-level metals and radionuclides in soils is needed for remedial investigations of contaminated sites. In this project, a total of 120 soil samples were collected from uncontaminated areas on and near the Oak Ridge Reservation. The samples were taken at three different depths and from three different geologic groups to establish background concentrations of metals and radionuclides. The objective of this presentation is to discuss the advantages and disadvantages of neutron activation analysis (NAA) compared with those of acid-digestion-based spectrometry (ADS) methods; the advantages and disadvantages were evaluated from Al, Sb, As, Cr, Co, Fe, Mg, Mn, Hg, K, Ag, 232 Th, 235 U, 238 U, V, and Zn data. The ADS methods used for this project were inductively coupled plasma (ICP), ICP-mass spectrometry (ICP-MS), and alpha spectrometry. The scatter plots showed that the NAA results for As, Co, Fe, Mn, 232 Th, and 238 U are reasonably correlated with the results from the other analytical methods. Compared to NAA, however, the ADS methods underestimated Al, Cr, Mg, K, V, and Zn. The skew distributions were caused by incomplete dissolution of the analytes during acid digestion of the soil samples. Because of the high detection limits of the spectrometric methods, the NAA results and the ADS results for some elements, including Sb, Hg, and Ag, did not show a definite relationship. The NAA results were highly correlated with the alpha spectrometry results for 232 Th and 238 U but poorly correlated for 235 U, probably because of a larger counting error associated with the lower activity of the isotope. The NAA methods, including the delayed neutron counting method, were far superior techniques for quantifying background levels of radionuclides ( 232 Th, 235 U, and 238 U) and metals (Al, Cr, Mg, K, V, and Zn) in soils

  11. Calculations of neutron and proton induced reaction cross sections for actinides in the energy region from 10 MeV to 1 GeV

    International Nuclear Information System (INIS)

    Konshin, V.A.

    1995-01-01

    Several nuclear model codes were applied to calculations of nuclear data in the energy region from 10 MeV to 1 GeV. At energies up to 100 MeV the nuclear theory code GNASH was used for nuclear data calculation for incident neutrons for 238 U, 233-236 U, 238-242 Pu, 237 Np, 232 Th, 241-243 Am and 242-247 Cm. At energies from 100 MeV to 1 GeV the intranuclear cascade exciton model including the fission process was applied to calculations of protons and neutrons with 233 U, 235 U, 238 U, 232 Th, 232 Pa, 237 Np, 238 Np, 239 Pu, 241 Am, 242 Am and 242-248 Cm. Determination of parameter systematics was a major effort in the present work that was aimed at improving the predictive capability of the models used. An emphasis was made on a simultaneous analysis of data for a variety of reaction channels for the nucleus considered, as well as of data that are available for nearby nuclei or other incident particles. Comparison with experimental data available on multiple reaction cross sections, isotope yields, fission cross sections, particle multiplicities, secondary particle spectra, and double differential cross sections indicates that the calculations reproduce the trends, and often the details, of the experimental data. (author)

  12. Calculations of neutron and proton induced reaction cross sections for actinides in the energy region from 10MeV to 1GeV

    International Nuclear Information System (INIS)

    Konshin, V.A.

    1995-06-01

    Several nuclear model codes were applied to calculations of nuclear data in the energy region from 10MeV to 1GeV. At energies up to 100MeV the nuclear theory code GNASH was used for nuclear data calculation for neutrons incident for on 238 U, 233-236 U, 238-242 Pu, 237 Np, 232 Th, 241-243 Am and 242-247 Cm. At energies from 100MeV to 1GeV the intranuclear cascade exciton model including the fission process was applied to calculations of protons and neutrons with 233 U, 235 U, 238 U, 232 Th, 232 Pa, 237 Np, 238 Np, 239 Pu, 241 Am, 242 Am and 242-248 Cm. Determination of parameter systematics was a major effort in the present work that was aimed at improving the predictive capability of the models used. An emphasis was placed upon a simultaneous analysis of data for a variety of reaction channels for the nuclei considered, as well as of data that are available for nearby nuclei or for other incident particles. Comparisons with experimental data available on multiple reaction cross sections, isotope yields, fission cross sections, particle multiplicities, secondary particle spectra, and double differential cross sections indicate that the calculations reproduce the trends, and often the details, of the measurements data. (author) 82 refs

  13. 238U decay series nuclides in the northeastern Arabian Sea: scavenging rates and cycling processes

    International Nuclear Information System (INIS)

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

    1994-01-01

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

  14. Measurement of natural and {sup 137}Cs radioactivity concentrations at Izmit Bay (Marmara Sea), Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Öksüz, İ., E-mail: ibrahim-ksz@yahoo.com; Güray, R. T., E-mail: tguray@kocaeli.edu.tr; Özkan, N., E-mail: nozkan@kocaeli.edu.tr; Yalçin, C., E-mail: caner.yalcin@kocaeli.edu.tr [Kocaeli University, Department of Physics, Umuttepe 41380, Kocaeli (Turkey); Ergül, H. A., E-mail: halim.ergul@kocaeli.edu.tr; Aksan, S., E-mail: serdar.aksan@kocaeli.edu.tr [Kocaeli University, Department of Biology, Umuttepe 41380, Kocaeli (Turkey)

    2016-03-25

    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 {sup 238}U, {sup 232}Th and {sup 40}K isotopes and also that of an artificial isotope {sup 137}Cs were measured by using gamma-ray spectroscopy. Preliminary results show that the radioactivity concentrations of {sup 238}U and {sup 232}Th isotopes are lower than the average worldwide values while the radioactivity concentrations of the {sup 40}K are higher than the average worldwide value. A small amount of {sup 137}Cs contamination, which might be caused by the Chernobyl accident, was also detected.

  15. Determination of natural radioactivity levels in sediments: Caravelas river, BA, Brazil

    International Nuclear Information System (INIS)

    Carmo, R.F.; Trindade Filho, O.L.; Delgado, J.U.; Peixoto, J.G. P.; Evangelista, H.

    2016-01-01

    Due to intensive human activity in the region and disorderly occupation, the Caravelas River estuary has not yet evaluated the contribution of natural radioactivity. In order to determine the natural radioactivity levels in sediments, the activities of "2"3"8U, "2"3"2Th and "4"0K, were calculated using a gamma spectrometry system for measuring the concentration of radiation in samples. Results for "2"3"8U, "2"3"2Th and "4"0K ranged from (18.03 to 191.51), (28.57 to 118.25) and (134.06 to 186.80) Bq.kg"-"1, respectively, within of detection limits. The estimated uncertainty levels were less than 10% (k = 1). (author)

  16. Determination of natural radioactivity levels in sediments: Caravelas river, BA, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, R.F.; Trindade Filho, O.L.; Delgado, J.U.; Peixoto, J.G. P., E-mail: rfcarmo@bolsista.ird.gov.br, E-mail: octavio@ird.gov.br, E-mail: delgado@ird.gov.br, E-mail: guilherm@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Evangelista, H., E-mail: evangelista.uerj@gmail.com [Lab. de Radioecologia e Mudancas Globais (LARAMG/UERJ), Rio de Janeiro, RJ (Brazil)

    2016-07-01

    Due to intensive human activity in the region and disorderly occupation, the Caravelas River estuary has not yet evaluated the contribution of natural radioactivity. In order to determine the natural radioactivity levels in sediments, the activities of {sup 238}U, {sup 232}Th and {sup 40}K, were calculated using a gamma spectrometry system for measuring the concentration of radiation in samples. Results for {sup 238}U, {sup 232}Th and {sup 40}K ranged from (18.03 to 191.51), (28.57 to 118.25) and (134.06 to 186.80) Bq.kg{sup -1}, respectively, within of detection limits. The estimated uncertainty levels were less than 10% (k = 1). (author)

  17. Radioactivity in honey of the central Italy.

    Science.gov (United States)

    Meli, Maria Assunta; Desideri, Donatella; Roselli, Carla; Feduzi, Laura; Benedetti, Claudio

    2016-07-01

    Natural radionuclides and (137)Cs in twenty seven honeys produced in a region of the Central Italy were determined by alpha ((235)U, (238)U, (210)Po, (232)Th and (228)Th) and gamma spectrometry ((137)Cs, (40)K, (226)Ra and (228)Ra). The study was carried out in order to estimate the background levels of natural ((40)K, (238)U and (232)Th and their progeny) and artificial radionuclides ((137)Cs) in various honey samples, as well as to compile a data base for radioactivity levels in that region. (40)K showed a mean activity of 28.1±23.0Bqkg(-1) with a range of 7.28-101Bqkg(-1). The mean of (210)Po activity resulted 0.40±0.46Bqkg(-1) with a range of 0.03-1.98Bqkg(-1). The mean of (238)U activity resulted 0.020±0.010Bqkg(-1). (226)Ra and (228)Ra resulted always <0.34 and <0.57Bqkg(-1) respectively, (235)U, (228)Th and (232)Th were always <0.007Bqkg(-1). (137)Cs resulted <0.10Bqkg(-1) in all samples. The committed effective doses due to (210)Po from ingestion of honey for infants, children and adults account for 0.002-5.13% of the natural radiation exposure in Italy. The honeys produced in Central Italy were of good quality in relation to the studied parameters, confirming the general image of a genuine and healthy food associated to this traditional products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Concentration of E2 strength near the fission barrier of 232Th

    International Nuclear Information System (INIS)

    Arruda Neto, J.D.T.; Vannucci, M.F.B.M.; Herdade, S.B.; Vannucci, A.; Nascimento, I.C. do.

    1981-08-01

    The electrofission angular distribution of 232 Th, in the energy interval 5.5-7 MeV, was measured. The analysis of substantial amount of E2 fission strength is concentrated near the fission barrier, corresponding to (8 +- 2)% of one energy weighted sum rule unity. (Author) [pt

  19. National low-level waste management program radionuclide report series, Volume 15: Uranium-238

    International Nuclear Information System (INIS)

    Adams, J.P.

    1995-09-01

    This report, Volume 15 of the National Low-Level Waste Management Program Radionuclide Report Series, discusses the radiological and chemical characteristics of uranium-238 ( 238 U). The purpose of the National Low-Level Waste Management Program Radionuclide Report Series is to provide information to state representatives and developers of low-level radioactive waste disposal facilities about the radiological, chemical, and physical characteristics of selected radionuclides and their behavior in the waste disposal facility environment. This report also includes discussions about waste types and forms in which 238 U can be found, and 238 U behavior in the environment and in the human body

  20. Determination of activity concentration levels of (238)U, (232)Th, and (40)K in drinking water in a gold mine in Ghana.

    Science.gov (United States)

    Awudu, A R; Darko, E O; Schandorf, C; Hayford, E K; Abekoe, M K; Ofori-Danson, P K

    2010-08-01

    The study of the activity concentration levels of uranium, thorium and potassium in drinking water from different locations in a gold mine in the Ashanti Region of Ghana was conducted using gamma spectrometry. The mean outdoor absorbed gamma dose rates at 1 m from the water were 0.524 nGy h, 0.422 nGy h, and 0.252 nGy h for groundwater, surface water, and treated water, respectively. The results obtained for the activity concentration levels of U and Th are found to be within the maximum acceptable concentration levels of 3.0 Bq L and 0.6 Bq L, respectively, recommended by the World Health Organization. The overall mean outdoor gamma dose rate is 0.41 nGy h and the corresponding outdoor annual effective dose obtained for adult members of the public for drinking water from the mines is 3.58 muSv y. This value is found to be within the 10.0 muSv per annum (0.01 mSv per annum) for public exposure control set by the World Health Organization. Therefore, the mining activities on drinking water studied did not show any significant radiological health implications on the public.

  1. Distribution of natural radionuclides in soils and beach sands of Abana-Çatalzeytin (Kastamonu)

    Energy Technology Data Exchange (ETDEWEB)

    Kurnaz, Aslı, E-mail: akurnaz@kastamonu.edu.tr; Özcan, Murat, E-mail: murat-ozcan@kastamonu.edu.tr; Çetiner, M. Atıf, E-mail: macetiner@kastamonu.edu.tr [Kastamonu University, Arts and Sciences Faculty, Department of Physics, Kastamonu (Turkey)

    2016-03-25

    A gamma spectrometric study of distribution of natural radionuclides in soil and beach sand samples collected from the terrestrial and coastal environment of Abana and Çatalzeytin counties of Kastamonu Province in Turkey was performed with the aim of estimating the radiation hazard of the tourist area and the concentrations of {sup 238}U, {sup 232}Th and {sup 40}K were determined. The activity concentrations of {sup 238}U, {sup 232}Th and {sup 40}K were determined in the ranges 14.95–56.0, 46.5–99.4 and 357.5–871.3 Bqkg{sup −1} for soil samples and the mean concentrations were ascertained as 42.34, 71.24 and 624.18 Bqkg{sup −1}, respectively. In sand samples, {sup 238}U, {sup 232}Th and {sup 40}K contents were varied in the ranges of 13.35-41.6, 30.9-53.4 and 275.5-601.3 Bqkg{sup −1} and the mean concentrations were ascertained as 20.57, 45.05 and 411.71 Bqkg{sup −1}, respectively. The mean annual effective doses were calculated as 113.08 and 69.16 µSvy{sup −1} for the soil and sand samples, respectively.

  2. 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

  3. 238U subthreshold neutron induced fission cross section

    International Nuclear Information System (INIS)

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

    1976-01-01

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

  4. Binary and ternary photofission of thorium 232

    Energy Technology Data Exchange (ETDEWEB)

    Titterton, E W; Brinkley, T A

    1950-05-01

    Work by Titterton and Goward (1949) has shown that uranium undergoes photofission into three charged fragments. Experiments have been conducted to determine whether a similar process takes place in the photofission of thorium. Some difficulties were encountered in loading plates with /sup 232/Th atoms, but this was finally accomplished by means of a technique described in detail. Plates loaded by this method were irradiated with a continuous spectrum of ..gamma.. rays of maximum energy 24 MeV from the (Atomic Energy Research Establishment) Synchrotron. Three irradiations, of 100, 150, and 180 r, were made and the resulting plates showed a fission density of 2.5 x 10/sup 4//cc at the 150 r level. In an examination involving 2500 binary photofissions, 5 cases of ternary fission involving the emission of a long range light fragment, probably an ..cap alpha..-particle, were observed. These events are described. A number-range curve was determined for the photofission tracks and is compared with a similar curve for tracks formed by the slow neutron fission of /sup 235/U in a D/sub 1/ emulsion under conditions of similar emulsion sensitivity. It appears that the energy release in the photofission of /sup 232/Th is smaller than that in the slow neutron fission of /sup 235/U. The data indicate that 124 MeV is the mean kinetic energy released in the photofission of /sup 232/Th.

  5. Concentration of some radionuclides in Moringa Oliefera plant

    International Nuclear Information System (INIS)

    Abd elbagi, W. K. A.

    2013-07-01

    This study has been conducted to determine the radioactivity concentration of naturally occurring radionuclides 228 U, 232 Th, and 40 K in samples of Moringaoliefera plants in Khartoum Bahry Elsamrab by using γ ray spectrometry sodium iodide detector and high purity germanium detector. A total of 30 samples, 10 samples from leaves, 10 samples from seeds and 10 samples from soil of samples have been collected. For leaves the radionuclide activity concentrations in samples analyzed with the mean of 2767.266±78.6741 Bq kg - 1 for 238 U, 3486.817±80.98811 Bq kg - 1 for 238 Th and 2273.386±54.152 Bq kg - 1 for 40 K. For seeds the radionuclide activity concentration in samples analyzed with the mean of 2839.224±72.6016 Bq kg - 1 for 238 U, 2844.372±78.74919 Bq kg - 1 for 2 38T h and 2377.005±91.8838 Bq kg - 1 for 40 K. No trace of artificial radionuclide has been determined in all the samples. The effective dose due to the presence of these radionuclides has been estimated and found 0.89μSv/year and 0.1015μSv/year for 232 Th, 238 U and 40 K, respectively.(Author)

  6. Mass distribution studies in 28Si + 232Th

    International Nuclear Information System (INIS)

    Sodaye, Suparna; Tripathi, R.; Sudarshan, K.; Pujari, P.K.

    2014-01-01

    Mass distribution is one of the important observables to understand the fusion-fission potential energy landscape. In the fission involving composite systems with Z ∼ 100, the fission barrier is lower and the saddle point is compact. Thus, apart from transfer induced fission,various non compound nucleus (NCN) fission processes like quasi-fission, pre-equilibrium fission and fast fission compete with the complete fusion fission (CFF). This would be further affected by the entrance channel parameters like choice of the target-projectile combination (mass asymmetry) and the projectile energy. Charge and mass distribution studies in such system would provide information about various fission processes such as complete fusion fission, non-compound nucleus fission and transfer induced fission, which would help in understanding the fusion-fission process in heavy ion collisions forming composite system in the heavy and trans-actinide region. In view of this, a systematic study of the charge and mass distribution in 28 Si+ 232 Th reaction was planned at beam energy close to and above the entrance channel Coulomb barrier. The experiments were carried out at the TIFR-LINAC booster facility. Self supporting foils of 232 Th were bombarded with 180 and 160 MeV 28 Si beam in a stack foil arrangement. The recoiling fission products were assayed radiochemically by off-line gamma-ray spectrometry. Results of charge distribution studies at E lab =180 MeV have been reported earlier. In the poster, the data on charge and mass distribution distribution will be presented.The results of the present studies will be compared with those from the reactions involving lighter and heavier composite systems

  7. Determination of Pb-210 and U-238 in environment samples by direct measurement using low energy γ spectrometry

    International Nuclear Information System (INIS)

    Godoy, J.M. de; Mendonca, A.H.; Sachett, I.A.

    1985-01-01

    The determination of Pb-210 and U-238 by γ spectrometry in environmental samples was carried out using the 47 KeV (4%) line for Pb-210 and the 63 KeV (3,9%) line from Th-234 to U-238. An intrinsic Ge detector with 0,8 KeV resolution for the 60 KeV line of Am-41 was employed. The eficiency was determined by using the radionuclide water solution. The samples were measured in a cylindric geometry with 7 cm diameter and 3 cm hight with a mass ranging from 25 to 180g, depending on the density. The self absorption correction factor for each sample was determined by using an external source of Pb-210 and Am-241. The results showed good agreement with the radiochemical analysis values. The diferences were lower than 20%; the detection limit changed from sample to sample staying on the pCi/g range for the 200 minutes couting time. (Author) [pt

  8. Determination of radioactivity in Chinese phosphate rock and fertilizer

    International Nuclear Information System (INIS)

    Chen Jingjian; Zhu Yongyi; Yang Juncheng

    1993-01-01

    The presented paper reported the radioactivity of U-238, Ra-226, Th-232 and K-40 in Chinese phosphate rocks by gamma spectrographic analysis during 1985-1990. The results showed that the decay chain of U-238-Ra-226 was the main source of radionuclides in phosphate rocks. The radionuclides in phosphate fertilizer differed from the forms of phosphate fertilizer. U-238 was the most important radionuclide in phosphoric compound fertilizer. The transfer rate of radionuclides was also estimated. (2 figs., 1 tab.)

  9. U-234/U-238 ratio: Qualitative estimate of groundwater flow in Rocky Flats monitoring wells

    International Nuclear Information System (INIS)

    Laul, J.C.

    1994-01-01

    Groundwater movement through various pathways is the primary mechanism for the transport of radionuclides and trace elements in a water/rock interaction. About three dozen wells, installed in the Rocky Flats Plant (RFP) Solar Evaporation Ponds (SEP) area, are monitored quarterly to evaluate the extent of any lateral and downgradient migration of contaminants from the Solar Evaporation Ponds: 207-A; 207-B North, 207-B Center, and 207-B South; and 207-C. The Solar Ponds are the main source for the various contaminants: radionuclides (U-238, U-234, Pu-239, 240 and Am-241); anions; and trace metals to groundwaters. The U-238 concentrations in Rocky Flats groundwaters vary from 2 (CO 3 ) 2 2- , because of the predominant bicarbonate medium

  10. Fuel utilization improvement in PWRs using the denatured 233U-Th cycle

    International Nuclear Information System (INIS)

    Jones, H.M.; Schwenk, G.A.; Toops, E.C.; Yotinen, V.O.

    1980-06-01

    A number of changes in PWR core design and/or operating strategy were evaluated to assess the fuel utilization improvement achievable by their implementation in a PWR using thorium-based fuel and operating in a recycle mode. The reference PWR for this study was identical to the B and W Standard Plant except that the fuel pellets were of denatured ( 233 U/ 238 U-Th)O 2 . An initial scoping study identified the three most promising improvement concepts as (1) a very tight lattice, (2) thorium blankets, and (3) ThO 2 rods placed in available guide tubes. A conceptual core design incorporating these changes was then developed, and the fuel utilization of this modified design was compared with that of the reference case

  11. Kinetic study of the precipitation of radioactive elements in the production process of phosphoric acid

    International Nuclear Information System (INIS)

    Ben Mahmoud, Souha

    2009-01-01

    In this engineering study we determined the activities of gamma emitting radionuclides belonging to the families of 238 U , 232 Th and 40K in phosphate, the acid derivatives and gypsum in Tunisian Chemical Group. The most important activities are those of 238 U and 226 Ra, which are located in the phosphate, gypsum and the precipitates formed in the pipes.

  12. Measurement of 226Ra, 232Th and 40K radioactivity contents in by-product phosphogypsum from phosphate fertilizer industry using gamma ray spectrometric method

    International Nuclear Information System (INIS)

    Demirel, H.; Parmaksiz, A.; Vural, M.; Cakir, I.T.; Demircioglu, B.; Yucel, H.

    2004-01-01

    Full text: Phosphatic fertilizers are produced from the industrial processing of rock phosphate ores which are known to contain naturally occurring radionuclides such as 238 U and its daughter products. A high volume by-product known as phosphogypsum (PG) from the production of phosphoric acid and phosphate fertilizer causes serious storage and environmental problems in phosphoric acid industries. During the phosphoric acid production process, 226 Ra (t 1/2 =1600 y) ends up in PG which has chemical analogous to calcium element. Since the stockpiles of PG near the phosphatic fertilizer plants are huge amounts, the radioactivity contained in PG has measured in view of environmental radioactivity problem. In this work, the natural radioactivity in eighty PG samples taken from a stock near Samsun phosphoric fertilizer plant was measured by a high resolution gamma ray spectrometer. The mean activity of 226 Ra in PG samples has been found to be 546 Bq.kg -1 . However, the activities of 232 Th and 40 K measured in PG samples are negligibly small. In the presented paper, the gamma spectrometric method employed for this work is discussed and the radiological risk impact of radon gas emanation from 226 Ra mainly contained in PG, has been assessed

  13. LA-ICP-MS and SIMS U-Pb and U-Th zircon geochronological data of Late Pleistocene lava domes of the Ciomadul Volcanic Dome Complex (Eastern Carpathians

    Directory of Open Access Journals (Sweden)

    Réka Lukács

    2018-06-01

    Full Text Available This article provides laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS and secondary ionization mass spectrometry (SIMS U-Pb and U-Th zircon dates for crystals separated from Late Pleistocene dacitic lava dome rocks of the Ciomadul Volcanic Dome Complex (Eastern Carpathians, Romania. The analyses were performed on unpolished zircon prism faces (termed rim analyses and on crystal interiors exposed through mechanical grinding an polishing (interior analyses. 206Pb/238U ages are corrected for Th-disequilibrium based on published and calculated distribution coefficients for U and Th using average whole-rock and individually analyzed zircon compositions. The data presented in this article were used for the Th-disequilibrium correction of (U-Th/He zircon geochronology data in the research article entitled “The onset of the volcanism in the Ciomadul Volcanic Dome Complex (Eastern Carpathians: eruption chronology and magma type variation” (Molnár et al., 2018 [1].

  14. Radioisotope dilution analyses of geological samples using 236U and 229Th

    International Nuclear Information System (INIS)

    Rosholt, J.N.

    1984-01-01

    The use of 236 U and 229 Th in alpha spectrometric measurements has some advantages over the use of other tracers and measurement techniques in isotope dilution analyses of most geological samples. The advantages are: 1) these isotopes do not occur in terrestrial rocks, 2) they have negligible decay losses because of their long half lives, 3) they cause minimal recoil contamination to surface-barrier detectors, 4) they allow for simultaneous determination of the concentration and isotopic composition of uranium and thorium in a variety of sample types, and 5) they allow for simple and constant corrections for spectral interferences, 0.5% of the 238 U activity is subtracted for the contribution of 235 U in the 236 U peak and 1% of the 229 Th activity is subtracted from the 230 Th activity. Disadvantages in using 236 U and 229 Th are: 1) individual separates of uranium and thorium must be prepared as very thin sources for alpha spectrometry, 2) good resolution in the spectrometer system is required for thorium isotopic measurements where measurement times may extend to 300 h, and 3) separate calibrations of the 236 U and 229 Th spike solution with both uranium and thorium standards are required. The use of these tracers in applications of uranium-series disequilibrium studies has simplified the measurements required for the determination of the isotopic composition of uranium and thorium because of the minimal corrections needed for alpha spectral interferences. (orig.)

  15. Radioisotope dilution analyses of geological samples using 236U and 229Th

    Science.gov (United States)

    Rosholt, J.N.

    1984-01-01

    The use of 236U and 229Th in alpha spectrometric measurements has some advantages over the use of other tracers and measurement techniques in isotope dilution analyses of most geological samples. The advantages are: (1) these isotopes do not occur in terrestrial rocks, (2) they have negligible decay losses because of their long half lives, (3) they cause minimal recoil contamination to surface-barrier detectors, (4) they allow for simultaneous determination of the concentration and isotopic composition of uranium and thorium in a variety of sample types, and (5) they allow for simple and constant corrections for spectral inferences, 0.5% of the 238U activity is subtracted for the contribution of 235U in the 236U peak and 1% of the 229Th activity is subtracted from the 230Th activity. Disadvantages in using 236U and 229Th are: (1) individual separates of uranium and thorium must be prepared as very thin sources for alpha spectrometry, (2) good resolution in the spectrometer system is required for thorium isotopic measurements where measurement times may extend to 300 h, and (3) separate calibrations of the 236U and 229Th spike solution with both uranium and thorium standards are required. The use of these tracers in applications of uranium-series disequilibrium studies has simplified the measurements required for the determination of the isotopic composition of uranium and thorium because of the minimal corrections needed for alpha spectral interferences. ?? 1984.

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

    International Nuclear Information System (INIS)

    Souza, Francisca de

    2006-01-01

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

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

    International Nuclear Information System (INIS)

    Latham, A.G.

    1991-01-01

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

  18. Electron scattering from the octupole band in 238U

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  19. Method for radioactivity monitoring

    Science.gov (United States)

    Umbarger, C. John; Cowder, Leo R.

    1976-10-26

    The disclosure relates to a method for analyzing uranium and/or thorium contents of liquid effluents preferably utilizing a sample containing counting chamber. Basically, 185.7-keV gamma rays following .sup.235 U alpha decay to .sup.231 Th which indicate .sup.235 U content and a 63-keV gamma ray doublet found in the nucleus of .sup.234 Pa, a granddaughter of .sup.238 U, are monitored and the ratio thereof taken to derive uranium content and isotopic enrichment .sup.235 U/.sup.235 U + .sup.238 U) in the liquid effluent. Thorium content is determined by monitoring the intensity of 238-keV gamma rays from the nucleus of .sup.212 Bi in the decay chain of .sup.232 Th.

  20. Thorium-230 dating of natural waters at the Nevada Test Site

    International Nuclear Information System (INIS)

    Bakhtiar, S.N.

    1990-01-01

    Radiocarbon determinations have been used in the past to estimate the ages of groundwater from the Paleozoic aquifer underlying the Nevada Test Site and adjacent areas. We measured the concentrations of 230 Th, 232 Th, 234 U and 238 U in several water samples taken from the wells and spring at the Nevada Test Site and calculated the 230 Th ages. 2 refs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-01-01

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

  2. Experimental 233U nondestructive assay with a random driver

    International Nuclear Information System (INIS)

    Goris, P.

    1979-01-01

    Nondestructive assay (NDA) of 233 U in quantities up to 15 grams containing 7 ppM 232 U age 2 years was investigated with a random driver. A passive singles counting technique showed a reproducibility within 0.2% at the 95% confidence level. This technique would be applicable throughout a process in which all of the 233 U had the same 232 U content at the same age. Where the 232 U content varies, determination of 233 U fissile content would require active NDA. Active coincidence counting utilizing a 238 Pu, Li neutron source and a plastic scintillator detector system showed a reproducibility limit within 15% at the 95% confidence limit. The active technique was found to be very dependent on the detector system resolving time in order to make proper random coincidence corrections associated with the high gamma activity from the 232 U decay chain

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

    Science.gov (United States)

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

    2016-12-01

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

  4. Neutron data evaluation of 232U

    International Nuclear Information System (INIS)

    Maslov, V.M.; Porodzinskij, Yu.V.; Tetereva, N.A.; Kagalenko, A.B.; Kornilov, N.V.; Baba, M.; Hasegawa, A.

    2003-03-01

    Consistent evaluation of 232 U measured data base is performed. Hauser-Feshbach- Moldauer theory, coupled channel model and double-humped fission barrier model are employed. Total, differential scattering, fission and (n,xn) data are consistently reproduced as a major constraint for inelastic scattering cross section estimate. The direct excitation of ground state and higher band levels is calculated within rigid rotator and soft (deformable) rotator mo