WorldWideScience

Sample records for 232th 237np 231pa

  1. 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...

  2. 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.

  3. Criticality of a {sup 237}Np Sphere

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Rene G.; Hayes, David K.; Cappiello, Charlene C.; Myers, William L.; Jaegers, Peter J.; Clement, Steven D.

    2003-07-22

    A critical mass experiment using a 6-kg {sup 237}Np sphere has been performed. The purpose of the experiment is to get a better estimate of the critical mass of {sup 237}Np. To attain criticality, the {sup 237}Np sphere was surrounded with 93 wt % {sup 235}U shells. A 1/M as a function of uranium mass was performed. An MCNP neutron transport code was used to model the experiment. The MCNP code yielded a k{sub eff} of 0.99089 {+-} 0.0003 compared with a k{sub eff} 1.0026 for the experiment. Based on these results, it is estimated that the critical mass of {sup 237}Np ranges from kilogram weights in the high fifties to low sixties.

  4. Measurements of {sup 237}Np secondary neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Kornilov, N.V.

    1997-03-01

    The activities carried out during the first year of the project are summarized. The main problems for Np spectra measurements arise from high intrinsic gamma-ray activity of the sample and admixture of the oxygen and iron nuclei. The inelastically scattered neutrons and the fission neutrons spectra for {sup 237}Np were measured by time-of-flight spectrometer of the IPPE at incident neutron energies {approx_equal}1.5 MeV, and {approx_equal}0.5 MeV. A solid tritium target and a Li-metallic target were used as neutron sources. The neutron scattering on C sample (C(n,n) standard reaction) was measured to normalize the Np data. The experimental data should be simulated by Monte Carlo method to correct the experimental data for oxygen and iron admixture as well as for multiple scattering of the neutrons in the sample. Therefore the response function of the spectrometer, and the neutron energy distribution from the source were investigated in detail. (author)

  5. Measurements of {sup 237}Np secondary neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Kornilov, N.V.

    1997-03-01

    The activities carried out during the first year of the project are summarized. The main problems for Np spectra measurements arise from high intrinsic gamma-ray activity of the sample and admixture of the oxygen and iron nuclei. The inelastically scattered neutrons and the fission neutrons spectra for {sup 237}Np were measured by time-of-flight spectrometer of the IPPE at incident neutron energies {approx_equal}1.5 MeV, and {approx_equal}0.5 MeV. A solid tritium target and a Li-metallic target were used as neutron sources. The neutron scattering on C sample (C(n,n) standard reaction) was measured to normalize the Np data. The experimental data should be simulated by Monte Carlo method to correct the experimental data for oxygen and iron admixture as well as for multiple scattering of the neutrons in the sample. Therefore the response function of the spectrometer, and the neutron energy distribution from the source were investigated in detail. (author)

  6. 231Pa systematics in postglacial volcanic rocks from Iceland

    Science.gov (United States)

    Turner, Simon; Kokfelt, Thomas; Hoernle, Kaj; Lundstrom, Craig; Hauff, Folkmar

    2016-07-01

    Several recent studies have highlighted the potential of combined 238U-230Th and 235U-231Pa systematics to constrain upwelling rates and the role of recycled mafic lithologies in mantle plume-derived basalts. Accordingly, we present measurements of the 231Pa concentrations from 26 mafic volcanic rocks from Iceland, including off-axis basalts from the Snaefellsnes Peninsula, to complement previously published 238U-230Th-226Ra data. 231Pa concentrations vary from 27 to 624 fg/g and (231Pa/235U) ratios from 1.12 to 2.11 with the exception of one anomalous sample from the Southeast Rift which has a 231Pa deficit with (231Pa/235U) = 0.86. An important new result is that basalts from the Southeast Rift and the Snaefellsnes Peninsula define a trend at relatively low (231Pa/235U) for a given (230Th/238U) ratio. Many of the remaining samples fall in or around the global field for ocean island basalts but those from the Mid-Iceland Belt and the Southwest Rift/Reykjanes Peninsula extend to higher (231Pa/235U) ratios at a given (230Th/238U), similar to mid-ocean ridge basalts. In principle, these lavas could result from melting of peridotite at lower pressures. However, there is no reason to suspect that the Mid-Iceland Belt and the Southwest Rift lavas reflect shallower melting than elsewhere in Iceland. In our preferred model, these lavas reflect melting of garnet peridotite whereas those from the Southeast Rift and the Snaefellsnes Peninsula contain a significant contribution (up to 20%) of melt from garnet pyroxenite. This is consistent with incompatible trace element and radiogenic isotope evidence for recycled oceanic crust in these lavas. There is increasing agreement that the displacement of ocean island basalts to lower (231Pa/235U) ratios at a given (230Th/238U), compared to mid-ocean ridge basalts, reflects the role of recycled mafic lithologies such as garnet pyroxenite as well as higher average pressures of melting. It now seems likely that this interpretation may

  7. 237 Np analytical method using 239 Np tracers and application to a contaminated nuclear disposal facility

    Energy Technology Data Exchange (ETDEWEB)

    Snow, Mathew S.; Morrison, Samuel S.; Clark, Sue B.; Olson, John E.; Watrous, Matthew G.

    2017-06-01

    Environmental 237Np analyses are challenged by low 237Np concentrations and lack of an available yield tracer; we report a rapid, inexpensive 237Np analytical approach employing the short lived 239Np (t1/2 = 2.3 days) as a chemical yield tracer followed by 237Np quantification using inductively coupled plasma-mass spectrometry. 239Np tracer is obtained via separation from a 243Am stock solution and standardized using gamma spectrometry immediately prior to sample processing. Rapid digestions using a commercial, 900 watt “Walmart” microwave and Parr microwave vessels result in 99.8 ± 0.1% digestion yields, while chromatographic separations enable Np/U separation factors on the order of 106 and total Np yields of 95 ± 4% (2σ). Application of this method to legacy soil samples surrounding a radioactive disposal facility (the Subsurface Disposal Area at Idaho National Laboratory) reveal the presence of low level 237Np contamination within 600 meters of this site, with maximum 237Np concentrations on the order of 103 times greater than nuclear weapons testing fallout levels.

  8. {sup 237}Np and {sup 57}Fe Moessbauer study of NpFeGa{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Homma, Y., E-mail: yhomma@imr.tohoku.ac.jp [Tohoku University, Institute for Materials Research (Japan); Nakada, M. [Japan Atomic Energy Research Institute, Nuclear Science and Engineering Directorate (Japan); Nakamura, A. [Japan Atomic Energy Research Institute, Advance Science Research Center (Japan); Nasu, S.; Aoki, D. [Tohoku University, Institute for Materials Research (Japan); Sakai, H.; Ikeda, S.; Yamamoto, E.; Haga, Y.; Onuki, Y. [Japan Atomic Energy Research Institute, Advance Science Research Center (Japan); Shiokawa, Y. [Tohoku University, Institute for Materials Research (Japan)

    2006-02-15

    {sup 57}Fe and {sup 237}Np Moessbauer Omeasurements have been performed for NpFeGa{sub 5}, which is one of the so-called neptunium 1-1-5 compounds. The {sup 57}Fe Moessbauer spectra below T{sub N} = 118 K show the magnetically ordered state. The magnitude of the hyperfine magnetic field at the {sup 57}Fe nucleus is determined to be 1.98 {+-} 0.05 T at 10 K. From the {sup 237}Np Moessbauer spectrum at 10 K, the hyperfine magnetic field at the {sup 237}Np nucleus is 203 T and the hyperfine coupling constant is determined to be 237 T/{mu}{sub B} using the Np atomic magnetic moment of 0.86 {mu}{sub B} determined by the neutron diffraction study.

  9. Delayed gamma studies from photo-fission of {sup 237}Np for nuclear waste characterization

    Energy Technology Data Exchange (ETDEWEB)

    Dighe, P.M. [CEA Saclay, IRFU/SPhN, 91191 Gif-sur-Yvette (France); Berthoumieux, E. [CEA Saclay, IRFU/SPhN, 91191 Gif-sur-Yvette (France)], E-mail: Eric.Berthoumieux@cea.fr; Dore, D. [CEA Saclay, IRFU/SPhN, 91191 Gif-sur-Yvette (France); Laborie, J.M.; Ledoux, X. [CEA, DPTA/SPN, Bruyeres-le-Chatel, 91297 Arpajon (France); Macary, V.; Panebianco, S.; Ridikas, D. [CEA Saclay, IRFU/SPhN, 91191 Gif-sur-Yvette (France)

    2009-04-15

    An active and non-destructive method is being established for detection of {sup 237}Np in nuclear waste barrels. The unique high energy decay gamma signature produced after photo-fission is analysed to deduce decay time parameters. A high purity {sup 237}Np sample was irradiated with bremsstrahlung photons and high energy gamma decay spectra were measured with BGO detectors for various irradiation durations. The analysis of decay spectra resulted in the formation of five decay groups, which can reproduce the experimental decay spectra within 10% accuracy. These parameters together with neutron decay groups are absolutely essential to quantify the nuclear material in waste barrels by photo-fission. The delayed decay gamma groups for {sup 237}Np nucleus are being reported for the first time.

  10. Delayed gamma studies from photo-fission of {sup 237}Np for nuclear waste characterization

    Energy Technology Data Exchange (ETDEWEB)

    Dighe, P.M.; Berthoumieux, E.; Dore, D.; Macary, V.; Panebianco, S.; Ridikas, D. [CEA/DSM Saclay, IRFU/SPhN, 91191 Gif-sur-Yvette (France); Laborie, J.M.; Ledoux, X. [CEA/DAM Ile-de-France, DPTA/SPN, 91680 Bruyeres-le-Chatel (France)

    2008-07-01

    An active and non destructive method is being established for detection of {sup 237}Np in nuclear waste barrels. The unique high-energy decay-gamma signature produced after photo-fission is analysed to deduce decay time parameters. High purity {sup 237}Np sample was irradiated with Bremsstrahlung photons and high energies gamma decay spectra were measured with BGO detectors for various irradiation durations. The analysis of decay spectra resulted in formation of five decay groups, which can reproduce the experimental decay spectra within 10 % accuracy. These parameters together with neutron decay groups are absolutely essential to quantify the nuclear material in waste barrels by photo-fission. The delayed decay gamma groups for {sup 237}Np nucleus are being reported for the first time. (authors)

  11. Reliable determination of 237Np in environmental solid samples using 242Pu as a potential tracer

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per;

    2011-01-01

    onto various AG 1-type anion exchangers; suitability of 242Pu as a tracer for 237Np determination in environmental solid samples; and long-term chemical stability of tetravalent Np. Experimental results revealed that the degree of resin cross-linking has a significant influence on the separation...

  12. (237)Np(n,f) Cross Section: New Data and Present Status

    CERN Document Server

    Paradela, C; Carrapico, C; Eleftheriadis, C; Leeb, H; Calvino, F; Herrera-Martinez, A; Savvidis, I; Vlachoudis, V; Haas, B; Vannini, G; Le Naour, C; Gramegna, F; Wiescher, M; Pigni, M T; Audouin, L; Mengoni, A; Quesada, J; Becvar, F; Plag, R; Cennini, P; Mosconi, M; Duran, I; Rauscher, T; Couture, A; Capote, R; Sarchiapone, L; Vlastou, R; Domingo-Pardo, C; Dillmann, I; Pavlopoulos, P; Karamanis, D; Krticka, M; Jericha, E; Ferrari, A; Martinez, T; Trubert, D; Oberhummer, H; Karadimos, D; Plompen, A; Isaev, S; Terlizzi, R; Kaeppeler, F; Cortes, G; Cox, J; Voss, F; Pretel, C; Colonna, N; Berthoumieux, E; Vaz, P; Heil, M; Lopes, I; Lampoudis, C; Walter, S; Calviani, M; Gonzalez-Romero, E; Embid-Segura, M; Stephan, C; Igashira, M; Papachristodoulou, C; Aerts, G; Tavora, L; Berthier, B; Rudolf, G; Andrzejewski, J; Villamarin, D; Ferreira-Marques, R; Tain, J L; O'Brien, S; Gunsing, F; Reifarth, R; Perrot, L; Lindote, A; Neves, F; Poch, A; Kerveno, M; Rubbia, C; Koehler, P; Dahlfors, M; Wisshak, K; Salgado, J; Dridi, W; Ventura, A; Andriamonje, S; Assimakopoulos, P; Santos, C; Ferrant, L; Lozano, M; Patronis, N; Chiaveri, E; Guerrero, C; Kadi, Y; Vicente, M C; Praena, J; Baumann, P; Oshima, M; Rullhusen, P; Furman, W; David, S; Marrone, S; Tassan-Got, L; Cano-Ott, D; Pavlix, A; Alvarez-Velarde, F; Massimi, C; Mastinu, P; Pancin, J; Papadopoulos, C; Tagliente, G; Haight, R; Chepel, V; Kossionides, E; Badurek, G; Marganiec, J; Lukic, S; Tarrio, D; Alvarez, H

    2011-01-01

    In this document, we present the final result obtained at the n_TOF experiment; for the neutron-induced fission cross section of the (237)Np, from the fission threshold up to 1 GeV. The method applied to get tins result is briefly discussed. n_TOF data are compared to the last experimental measurements using other TOF facilities or the surrogate method, reported experiments performed with monoenergetic sources and the FISCAL systematic, including a discussion about the existing discrepancies.

  13. Nuclear Resonance Fluorescence Measurements on ^237Np for Security and Safeguards Applications

    Science.gov (United States)

    Angell, C. T.; Joshi, T.; Yee, Ryan; Norman, E. B.; Kulp, W. D.; Warren, G. A.; Korbly, S.; Klimenko, A.; Wilson, C.; Copping, R.; Shuh, D. K.

    2009-10-01

    The smuggling of nuclear material and the diversion of fissile material for covert weapon programs both present grave risks to world security. Methods are needed to detect nuclear material smuggled in cargo, and for proper material accountability in civilian fuel re-processing facilities. Nuclear resonance fluorescence (NRF) is a technique that can address both needs. It is a non-destructive active interrogation method that provides isotope-specific information. It works by using a γ-ray beam to resonantly excite levels in a nucleus and observing the γ-rays emitted whose energy and intensity are characteristic of that isotope. ^237Np presents significant safeguard challenges; it is fissile yet currently has fewer safeguard restrictions. NRF measurements on ^237Np will expand the nuclear database and will permit designing interrogation and assay systems. Measurements were made using the bremsstrahlung beam at the HVRL at MIT on a 7 g target of ^237Np with two incident electron energies of 2.8 and 3.1 MeV. Results will be presented with discussion of the relevant nuclear structure necessary to predict levels in other actinides.

  14. RAPID SEPARATION METHOD FOR 237NP AND PU ISOTOPES IN LARGE SOIL SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Culligan, B.; Noyes, G.

    2010-07-26

    A new rapid method for the determination of {sup 237}Np and Pu isotopes in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for large soil samples. The new soil method utilizes an acid leaching method, iron/titanium hydroxide precipitation, a lanthanum fluoride soil matrix removal step, and a rapid column separation process with TEVA Resin. The large soil matrix is removed easily and rapidly using this two simple precipitations with high chemical recoveries and effective removal of interferences. Vacuum box technology and rapid flow rates are used to reduce analytical time.

  15. 231Pa/230Th records of Arctic/Atlantic interchange in Fram Strait

    Science.gov (United States)

    Hoffmann, S. S.; McDermott, K. J.; McManus, J. F.; Mukasa, S. B.

    2014-12-01

    Fram Strait, the Arctic Ocean's only deep passage for exchange with lower latitude oceans, today serves as a conduit for waters flowing north into the Arctic Ocean and south into the Atlantic. Reconstruction of circulation patterns and strength at depth in the strait can help to clarify the history of Arctic/Atlantic deep water exchange and Arctic contributions to global meridional overturning circulation. We will present new sedimentary measurements of radioisotopes 231Pa and 230Th to provide information on this exchange in the past and its relationship to sedimentation and climatic events. Coretop and downcore 231Pa/230Th ratios from Arctic sediments indicate that 231Pa has been exported from the central Arctic basin throughout the Holocene and deglaciation. Fram Strait represents a possible sink for this "missing" 231Pa. Preliminary results from ODP Holes 908A and 909A, at 1274 m and 2519 m water depths respectively in the central strait, suggest that ratios in this region during the Holocene have varied between ~0.106 (above the 231Pa/230Th production ratio of 0.093 in seawater, indicating net import of 231Pa)and ~0.055 (well below the production ratio, indicating net export of 231Pa). Further measurements in cores from the Greenland and Svalbard continental slopes will give a fuller regional picture of 231Pa deposition and transport across the strait.

  16. Moessbauer Spectroscopic Studies of {sup 237}Np in frozen nitric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Nakada, M; Wang, J; Kitazawa, T; Takahashi, M; Takeda, M; Masaki, N M; Yamashita, T [Department of Materials Science, Japan Atomic Energy Research Institute (JAERI, present JAEA: Japan Atomic Energy Agency), Tokai, Naka, Ibaraki 319-1195 (Japan); Tsutsui, S, E-mail: wangjh@dicp.ac.c [Advanced Science Research Center, JAERI, Tokai, Naka, Ibaraki 319-1195 (Japan)

    2010-03-01

    We applied Moessbauer spectroscopy to {sup 237}Np in nitric acid solutions to study chemical states. Sample solutions were adjusted to 50 mg/ml of Np(V) and Np(VI) concentration in 0.6 M nitric acid solutions. These solutions were put into original designed containers for samples and mounted to sample holders. The values of isomer shift (IS, relative to NpAl{sub 2}) of Np(V) and Np(VI) in 0.6 M nitric acid were -17.4(1) and -37.2(3) mm/s at about 10 K, respectively. It was found that Np(V) had 7 coordination number and Np(VI) had 8 in nitric acid solutions from values of IS.

  17. Development of ionization technique for measurement of fast neutron induced fission products yields of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Goverdovski, A.A.; Khryachkov, V.A.; Ketlerov, V.V.; Mitrofanov, V.F.; Ostapenko, Yu.B.; Semenova, N.N.; Fomichev, A.N.; Rodina, L.F. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    Twin gridded ionization chamber and corresponding software was designed for measurements of masses, kinetic energies and nuclear charges of fission fragments from fast neutron induced fission of {sup 237}Np. The ionization detector design, electronics, data acquisition and processing system and the test results are presented in this paper. (J.P.N.)

  18. DETERMINATION OF 237NP AND PU ISOTOPES IN LARGE SOIL SAMPLES BY INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.

    2010-07-26

    A new method for the determination of {sup 237}Np and Pu isotopes in large soil samples has been developed that provides enhanced uranium removal to facilitate assay by inductively coupled plasma mass spectrometry (ICP-MS). This method allows rapid preconcentration and separation of plutonium and neptunium in large soil samples for the measurement of {sup 237}Np and Pu isotopes by ICP-MS. {sup 238}U can interfere with {sup 239}Pu measurement by ICP-MS as {sup 238}UH{sup +} mass overlap and {sup 237}Np via {sup 238}U peak tailing. The method provides enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then transferring Pu to DGA resin for additional purification. The decontamination factor for removal of uranium from plutonium for this method is greater than 1 x 10{sup 6}. Alpha spectrometry can also be applied so that the shorter-lived {sup 238}Pu isotope can be measured successfully. {sup 239}Pu, {sup 242}Pu and {sup 237}Np were measured by ICP-MS, while {sup 236}Pu and {sup 238}Pu were measured by alpha spectrometry.

  19. Development of ionization technique for measurement of fast neutron induced fission products yields of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Goverdovski, A.A.; Khryachkov, V.A.; Ketlerov, V.V.; Mitrofanov, V.F.; Ostapenko, Yu.B.; Semenova, N.N.; Fomichev, A.N.; Rodina, L.F. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    Twin gridded ionization chamber and corresponding software was designed for measurements of masses, kinetic energies and nuclear charges of fission fragments from fast neutron induced fission of {sup 237}Np. The ionization detector design, electronics, data acquisition and processing system and the test results are presented in this paper. (J.P.N.)

  20. Determination of traces of 237Np in environmental samples by ICP-MS after separation using TOA extraction chromatography.

    Science.gov (United States)

    Ji, Y Q; Li, J Y; Luo, S G; Wu, T; Liu, J L

    2001-09-01

    A simple, rapid, cost-efficient, and robust method for separation of 237Np with an extraction chromatographic column (TOA: tri-n-octylamine on Teflon powder) is outlined in detail and further improved for direct ICP-MS analysis. The column efficiently retained 237Np in 2 mol L(-1) HNO3 medium and all of the 237Np was easily eluted with 0.02 mol L(-1) oxalic acid in 0.16 mol L(-1) HNO3 at 95 degrees C. The separated solutions were free from most matrix elements and were aspirated into the ICP-MS directly. The decontamination factor for 238U is more than 10(4). The instrumental detection limit for 237Np was 0.46 pg mL(-1), which corresponds to 1.2 x 10(-5) Bq mL(-1). The method is more rapid than traditional radiometric techniques. It is also considered to be more suitable for environmental monitoring than existing methods based on TOA.

  1. Fission mode analysis of the reaction {sup 237}Np(n,f) - possibilities and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Siegler, P. [Joint Research Centre, Geel (Belgium). Geel Establishment

    1996-03-01

    Fission fragment properties for the reaction {sup 237}Np(n,f) have been measured at the Van de Graaff Laboratory of the IRMM. Using a double gridded ionization chamber the mass, kinetic energy and the angular distribution for both fission fragments could be determined simultaneously for an incident neutron energy range from E{sub n}=0.3 MeV upto E{sub n}=5.5 MeV. Complete datasets have been acquired for 13 different neutron energies covering sub barrier fission as well as fission in the plateau region. A detailed analysis of the fragment distributions and the respective momenta has been carried out, checking the coherence against the excitation energy of the compound nucleus. The consideration of multi-modal fission offers an improved possibility for the description of the fragment distributions backed up by theoretical calculations on the basis of the multi-model random-neck rupture model of Brosa, Grossmann and Mueller. The changes of the fission fragment properties under investigation are completely described and an interpretation of the findings is presented. (author)

  2. Diffusion coefficient test of {sup 237}Np in bentonite backfill materials

    Energy Technology Data Exchange (ETDEWEB)

    Cui Anxi; Fan Zhiwen; Zhang Jinsheng; Gu Cunli [China Inst. for Radiation Protection, Shanxi (China); Mukai, M.; Maeda, T.; Matsumoto, J.; Tanaka, T.; Ogawa, H. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-03-01

    This paper describes the work on diffusion coefficient test of Np in bentonite backfill materials. Due to its very low permeability, diffusion is the dominant migration mechanics in bentonite. The bentonite comes from Inner Mongolia of China. {sup 237}Np was used as tracer. The special apparatus for diffusion test was setup, the diffusion coefficient of Np in pure bentonite and sand-bentonite mixture were tested. The tracer was introduced between two bentonite columns. After a specific contacting period, the bentonite columns were taken out and cut to very thin slices. The radioactivity in bentonite slices was analyzed to give the nuclide concentration versus distance curves. The diffusion coefficient could be estimated. The diffusion coefficient of pure bentonite at different density was tested. When the density of pure bentonite samples varied from 1.1, 1.3, 1.5 to 1.7 g/ml, their diffusion coefficient were 1.36 x 10{sup -13} m{sup 2}/s 1.16 x 10{sup -13}m{sup 2}/s, 1.07 x 10{sup -13} m{sup 2}/s and 8.26 x 10{sup -14} m{sup 2}/s respectively. The diffusion coefficient of Np in sand-bentonite mixture sample was 4.13 x 10{sup -13} m{sup 2}/s. To estimate the distribution coefficient (K{sub d}) value of Np in mixture sample by diffusion method, the diffusion coefficient of Br was measured./ The concluded K{sub d} value was 77ml/g for the sand-bentonite mixture. The K{sub d} value obtained by batch test methods was 30ml/g. The reason is related with the error of Br diffusion coefficient and solid-liquid ratio. (author)

  3. New experimental determination of the neutronic resonance parameters of {sup 237}Np below 500 eV; Nouvelle determination experimentale des parametres de resonances neutroniques de {sup 237}Np en dessous de 500 eV

    Energy Technology Data Exchange (ETDEWEB)

    Gressier, V

    1999-10-01

    For studies of future nuclear reactors dedicated to nuclear waste transmutation, an improvement of the accuracy of the neutron radiative capture cross section of {sup 237}Np appears necessary. In the framework of a collaboration between the Commissariat a l'Energie atomique (CEA) and Institute for Reference Materials and Measurement (IRMM, Geel, Bergium), a new determination of the resonance parameters of {sup 237}Np has been performed. Two types of experiments are carried out at GELINA, the IRMM pulsed neutron source, using the time of flight method: a transmission experiment which is related to the neutron total cross section and a capture experiment which gives the neutron radiative capture cross section. The resonance parameters presented in this work are extracted from the transmission data between 0 and 500 eV with the least square code REFIT, using the Reich-Moore formalism. In parallel, the Doppler effect is investigated. The commonly used free gas model appears inadequate below 20 eV for neptunium dioxide at room temperature. By the use of the program DOPUSH, which calculates the Doppler broadening with a harmonic crystal model according to Lamb's theory, we are able to produce abetter fit of the experimental data for the resonances of {sup 237}Np in NpO{sub 2} at low energy or temperatures. In addition to the resonance parameters, a study of their mean value and distribution is included in this work. (authors)

  4. RAPID DETERMINATION OF 237 NP AND PU ISOTOPES IN WATER BY INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S.; Jones, V.; Culligan, B.; Nichols, S.; Noyes, G.

    2010-06-23

    A new method that allows rapid preconcentration and separation of plutonium and neptunium in water samples was developed for the measurement of {sup 237}Np and Pu isotopes by inductively-coupled plasma mass spectrometry (ICP-MS) and alpha spectrometry; a hybrid approach. {sup 238}U can interfere with {sup 239}Pu measurement by ICP-MS as {sup 238}UH{sup +} mass overlap and {sup 237}Np via peak tailing. The method provide enhanced removal of uranium by separating Pu and Np initially on TEVA Resin, then moving Pu to DGA resin for additional removal of uranium. The decontamination factor for uranium from Pu is almost 100,000 and the decontamination factor for U from Np is greater than 10,000. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration is performed using a streamlined calcium phosphate precipitation method. Purified solutions are split between ICP-MS and alpha spectrometry so that long and short-lived Pu isotopes can be measured successfully. The method allows for simultaneous extraction of 20 samples (including QC samples) in 4 to 6 hours, and can also be used for emergency response. {sup 239}Pu, {sup 242}Pu and {sup 237}Np were measured by ICP-MS, while {sup 236}Pu, {sup 238}Pu, and {sup 239}Pu were measured by alpha spectrometry.

  5. Dispersion amplitudes in the Moessbauer lineshape of /sup 237/Np, /sup 182/W, and /sup 195/Pt

    Energy Technology Data Exchange (ETDEWEB)

    Potzel, W. (Technische Universitaet Muenchen, Garching, Ger.); Wagner, F.E.; Kalvius, G.M.; Asch, L.; Spirlet, J.C.; Mueller, W.

    1977-01-01

    Measurements of the dispersion amplitude for the Moessbauer resonances in /sup 237/Np (60 keV), /sup 182/W (100 keV) and /sup 195/Pt (99 keV) are reported. For the E1 transition in /sup 237/Np a value of xi = -(3.4 + 0.2) x 10/sup -2/ was found. Theoretical estimates of xi for this case are of limited accuracy and the comparison with experimental data is inaccurate because of the considerable line broadening. Computer simulations show the influence of xi on /sup 237/Np hyperfine spectra. For the E2 transition in /sup 182/W the dependence of the effective value of xi on absorber thickness was studied. Extrapolations to zero thickness yield xi = -(1.0 +- 0.1) x 10/sup -2/ in good agreement with theoretical calculations. For /sup 195/Pt we found xi = -(1.1 +- 0.3) x 10/sup -2/ for the dispersion amplitude at zero absorber thickness. This is the first pure M1 transition for which a dispersion term has been observed. For all three resonances the dispersion is large enough to affect the determination of isomer shifts.

  6. 230Thand 231Pa in Seawater Sinking Particles from the North Atlantic GEOTRACES Transect

    Science.gov (United States)

    LU, Y.; Edwards, R. L.; Cheng, H.; Anderson, R. F.; Hayes, C. T.; Fleisher, M. Q.; Lam, P. J.; Huang, K. F.; Robinson, L. F.; Wang, X.

    2016-12-01

    The biological carbon pump in the ocean plays a key role in regulating atmospheric CO2 level via oceanic particle dynamics. Radionuclides with proper half-lives, like 230Th and 231Pa, can provide quantitative estimates of particle cycling on the timescales up to hundred thousand years. However, our understanding of particle dynamics is hindered by the difficulty in precisely determining particulate 230Th and 231Pa, due to the trace amounts of Th and Pa in seawater, especially in large sinking particles. Here, we developed a technique to measure sinking particulate 230Th and 231Pa in a small sample size (tens to hundreds attograms of 231Pa, equivalent to 100 L water pumped through QMA filter), and achieved an average precision in percentage level. We firstly applied leaching processes to the particulate samples. The samples were soaked in 8N HNO3 + 0.5N HF mixed with proportionally determined 229Th and 233Pa spikes, and heated at 100°C for 10 hours. Th and Pa were then pre-concentrated by co-precipitation with Fe. After HNO3-HClO4-HNO3 digestion of the precipitates, Th and Pa were separated and purified using anion exchange chromatography (Spectra/Gel anion resin 1x8). Pa was measured on a MC-ICP-MS instrument (Neptune) right after the chemistry in order to minimize the 233Pa "bleeding effect". Replication tests show a good agreement in 231Pa/230Th within the measurement uncertainties. Applying our method to the profile samples collected from the North Atlantic GEOTRACES Transect, we found that the concentrations of 230Th and 231Pa in sinking particles (>51 μm size fraction; attograms/liter) are about 1/10 of those in suspended ones (1 - 51 μm size fraction). The scavenging of Th and Pa to large particles appears to be a function of particle composition (CaCO3, POM, lithogenic, opal and Fe/Mn oxides). In addition, ratios of the adsorbed 231Pa to 230Th are the same in both types of particles, although the particles have significantly different residence time in

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

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

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

  8. Preparation of 232Th Target by Molecule Plating

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

  9. Radiation protection potential of MOX-fuel doped with 231Pa and Cs radioisotopes.

    Science.gov (United States)

    Kryuchkov, E F; Glebov, V B; Apse, V A; Shmelev, A N

    2005-01-01

    The paper addresses the problem of MOX-fuel self-protection during full cycle of MOX-fuel management. Under conditions of the closed LWR cycle the proliferation-resistance levels were evaluated for fresh and spent MOX-fuel with 231Pa and Cs feed. As it follows from the paper results, combination of these two admixtures being doped into MOX-fuel is able to enhance the inherent radiation barrier and to weaken shortcomings of both proliferation deterrents.

  10. Holocene Paleocirculation from 231Pa/230Th in Sediments from the North Atlantic Ocean

    Science.gov (United States)

    McManus, J.; Francois, R.; Major, C.; Gherardi, J.; Hoffman, S.

    2004-12-01

    A new record of bulk sedimentary 231Pa/230Th excesses from core GGC5 on the Bermuda Rise has been produced by ICP-MS. The record reveals several aspects of the strength of the meridional overturning circulation during the last ten thousand years. Measurements of uranium, protactinium and thorium in the Holocene section recovered in GGC5 have been resolved at approximately 200-300 years, similar to the response time of excess 231Pa in the water column, and therefore should capture any large departure from modern values in the 231Pa/230Th indicator of paleocirculation. No dramatic increase in ratio or decrease in circulation is indicated by the data, which suggest vigorous overturning in the western basin of the North Atlantic since the end of the Younger Dryas. Instead of large changes in circulation, a series of oscillations punctuates the middle Holocene, indicating a variability of 10-20 percent in the rate of meridional overturning. Specific attention will be paid to millennial events postulated at 8.2 kyr, ~5 kyr, and in the most recent Holocene.

  11. Persistent export of 231Pa from the deep central Arctic Ocean over the past 35,000 years.

    Science.gov (United States)

    Hoffmann, Sharon S; McManus, Jerry F; Curry, William B; Brown-Leger, L Susan

    2013-05-30

    The Arctic Ocean has an important role in Earth's climate, both through surface processes such as sea-ice formation and transport, and through the production and export of waters at depth that contribute to the global thermohaline circulation. Deciphering the deep Arctic Ocean's palaeo-oceanographic history is a crucial part of understanding its role in climatic change. Here we show that sedimentary ratios of the radionuclides thorium-230 ((230)Th) and protactinium-231 ((231)Pa), which are produced in sea water and removed by particle scavenging on timescales of decades to centuries, respectively, record consistent evidence for the export of (231)Pa from the deep Arctic and may indicate continuous deep-water exchange between the Arctic and Atlantic oceans throughout the past 35,000 years. Seven well-dated box-core records provide a comprehensive overview of (231)Pa and (230)Th burial in Arctic sediments during glacial, deglacial and interglacial conditions. Sedimentary (231)Pa/(230)Th ratios decrease nearly linearly with increasing water depth above the core sites, indicating efficient particle scavenging in the upper water column and greater influence of removal by lateral transport at depth. Although the measured (230)Th burial is in balance with its production in Arctic sea water, integrated depth profiles for all time intervals reveal a deficit in (231)Pa burial that can be balanced only by lateral export in the water column. Because no enhanced sink for (231)Pa has yet been found in the Arctic, our records suggest that deep-water exchange through the Fram strait may export (231)Pa. Such export may have continued for the past 35,000 years, suggesting a century-scale replacement time for deep waters in the Arctic Ocean since the most recent glaciation and a persistent contribution of Arctic waters to the global ocean circulation.

  12. Concurrent determination of 237Np and Pu isotopes using ICP-MS: analysis of NIST environmental matrix standard reference materials 4357, 1646a, and 2702.

    Science.gov (United States)

    Matteson, Brent S; Hanson, Susan K; Miller, Jeffrey L; Oldham, Warren J

    2015-04-01

    An optimized method was developed to analyze environmental soil and sediment samples for (237)Np, (239)Pu, and (240)Pu by ICP-MS using a (242)Pu isotope dilution standard. The high yield, short time frame required for analysis, and the commercial availability of the (242)Pu tracer are significant advantages of the method. Control experiments designed to assess method uncertainty, including variation in inter-element fractionation that occurs during the purification protocol, suggest that the overall precision for measurements of (237)Np is typically on the order of ± 5%. Measurements of the (237)Np concentration in a Peruvian Soil blank (NIST SRM 4355) spiked with a known concentration of (237)Np tracer confirmed the accuracy of the method, agreeing well with the expected value. The method has been used to determine neptunium and plutonium concentrations in several environmental matrix standard reference materials available from NIST: SRM 4357 (Radioactivity Standard), SRM 1646a (Estuarine Sediment) and SRM 2702 (Inorganics in Marine Sediment).

  13. Mass and nuclear charge yields for sup 237 Np(2n sub th ,f) at different fission fragment kinetic energies

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, G.; Barreau, G.; Sicre, A.; Doan, T.P.; Audouard, P.; Leroux, B. (CEA Centre d' Etudes Nucleaires de Bordeaux-Gradignan, 33 - Gradignan (France)); Arafa, W.; Brissot, R.; Bocquet, J.P. (Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires); Faust, H. (Institut Max von Laue - Paul Langevin, 38 - Grenoble (France)); Koczon, P.; Mutterer, M. (Technische Hochschule Darmstadt (Germany, F.R.). Inst. fuer Kernphysik); Goennenwein, F. (Tuebingen Univ. (Germany, F.R.). Physikalisches Inst.); Asghar, M. (Universite des Sciences et de la Technologie Houari Boumediene, Algiers (Algeria). Inst. de Physique); Quade, U.; Rudolph, K. (Muenchen Univ. (Germany, F.R.)); Engelhardt, D. (Karlsruhe Univ. (T.H.) (Germany, F.R.)); Piasecki, E. (Warsaw Univ. (Poland))

    1990-09-03

    The recoil mass separator LOHENGRIN of the Laue-Langevin Institute Grenoble has been used to measure for the first time, the yields of light fission fragments from the fissioning system: {sub 93}{sup 239}Np; this odd-Z nucleus is formed after double thermal neutron capture in a {sub 93}{sup 237}Np target. The mass distributions were measured for different kinetic energies between 92 and 115.5 MeV, but the nuclear charge distributions were determined only up to 112 MeV. These distributions are compared to the distributions obtained for the even-even system {sub 94}{sup 240}Pu. At high kinetic energy, the mass distribution shows a prominent peak around mass number A{sub L}=106. These cold fragmentations are discussed in terms of a calculation based on a scission point model extrapolated to the cold fission case. As expected for an odd-Z fissioning nucleus, the nuclear charge distributions do not reveal any odd-even effect. The global neutron odd-even effect is found to be (8.1{plus minus}1.5)%. A simple model has been used to show that most of the neutron odd-even effect results from prompt neutron evaporation from the fragments. (orig.).

  14. Neutron-induced transmutation reactions in 237Np, 238Pu, and 239Pu at the massive natural uranium spallation target

    Science.gov (United States)

    Zavorka, L.; Adam, J.; Baldin, A. A.; Caloun, P.; Chilap, V. V.; Furman, W. I.; Kadykov, M. G.; Khushvaktov, J.; Pronskikh, V. S.; Solnyshkin, A. A.; Sotnikov, V.; Stegailov, V. I.; Suchopar, M.; Tsoupko-Sitnikov, V. M.; Tyutyunnikov, S. I.; Voronko, V.; Vrzalova, J.

    2015-04-01

    Transmutation reactions in the 237Np, 238Pu, and 239Pu samples were investigated in the neutron field generated inside a massive (m = 512 kg) natural uranium spallation target. The uranium target assembly QUINTA was irradiated with the deuteron beams of kinetic energy 2, 4, and 8 GeV provided by the Nuclotron accelerator at the Joint Institute for Nuclear Research (JINR) in Dubna. The neutron-induced transmutation of the actinide samples was measured off-line by implementing methods of gamma-ray spectrometry with HPGe detectors. Results of measurement are expressed in the form of both the individual reaction rates and average fission transmutation rates. For the purpose of validation of radiation transport programs, the experimental results were compared with simulations of neutron production and distribution performed by the MCNPX 2.7 and MARS15 codes employing the INCL4-ABLA physics models and LAQGSM event generator, respectively. In general, a good agreement between the experimental and calculated reaction rates was found in the whole interval of provided beam energies.

  15. Studies of Long-lived Radionuclides in the Environment - with Emphasis on {sup 99}Tc, {sup 237}Np and Pu Isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, Patric

    2003-03-01

    Studies of the long-lived anthropogenic radionuclides 99Tc, 237Np, 239Pu and 240Pu were performed in marine and terrestrial areas contaminated by different accidental and controlled releases of radioactive materials. The three main sources discussed in this thesis are nuclear weapons tests, nuclear reprocessing plants and the Chernobyl accident. Results are mainly based on measurements of environmental samples collected in different parts of Sweden. An analytical method for trace analysis of plutonium and neptunium in environmental samples using ICP-MS (Inductively Coupled Plasma Mass Spectrometry) is described, and the results compared with those from conventional alpha spectrometry. The use of activated carbon filters for the separation of 99Tc from marine waters, with an adsorption efficiency in the range of 70%, is described. During 1991, 1995 and 2001 brown seaweed samples were collected at several stations along the Swedish west coast. In addition to these locations, a well-defined site (Saerdal; 56.76 deg N, 12.63 deg E) was included from which 99Tc data were collected from 1967 to 2000. The effect of discharges from the Sellafield EARP (Enhanced Actinide Removal Plant) from 1995-1996 was observed in brown seaweed from the Swedish west coast 4-5 years later, with a ten-fold increase in 99Tc activity concentration. An inverse correlation between 99Tc and 137Cs concentrations in seaweed was observed due to continuous mixing of high-Tc-low-Cs (Atlantic Sea) and low-Tc-high-Cs (Baltic Sea) waters. Radioactive materials from the Chernobyl accident contaminated various part of Sweden and by analysing lichen samples from different areas an estimate of the deposited 237Np density could be made. Through the determination of 240Pu/239Pu and 237Np/239Pu atomic ratios, source identification could be made in Swedish lichen samples. In the areas most contaminated by the Chernobyl accident in Sweden, the Chernobyl-derived 237Np contribution was up to 30% of the total

  16. Meridional circulation across the Antarctic Circumpolar Current serves as a double 231Pa and 230Th trap

    Science.gov (United States)

    Rutgers van der Loeff, Michiel; Venchiarutti, Celia; Stimac, Ingrid; van Ooijen, Jan; Huhn, Oliver; Rohardt, Gerd; Strass, Volker

    2016-12-01

    Upwelling of Circumpolar Deep Water in the Weddell Gyre and low scavenging rates south of the Antarctic Circumpolar Current (ACC) cause an accumulation of particle reactive nuclides in the Weddell Gyre. A ventilation/reversible scavenging model that successfully described the accumulation of 230Th in this area was tested with other particle reactive nuclides and failed to adequately describe the depth-distributions of 231Pa and 210Pb. We present here a modified model that includes a nutrient-like accumulation south of the Antarctic Polar Front in an upper meridional circulation cell, as well as transport to a deep circulation cell in the Weddell Gyre by scavenging and subsequent release at depth. The model also explains depletion of 231Pa and 230Th in Weddell Sea Bottom Water (WSBW) by ventilation of newly formed deep water on a timescale of 10 years, but this water mass is too dense to leave the Weddell Gyre. In order to quantify the processes responsible for the 231Pa- and 230Th-composition of newly formed Antarctic Bottom Water (AABW) we present a mass balance of 231Pa and 230Th in the Atlantic sector of the Southern Ocean based on new data from the GEOTRACES program. The ACC receives 6.0 ± 1.5 ×106 dpms-1 of 230Th from the Weddell Sea, similar in magnitude to the net input of 4.2 ± 3.0 ×106 dpms-1 from the north. For 231Pa, the relative contribution from the Weddell Sea is much smaller, only 0.3 ± 0.1 ×106, compared to 2.7 ± 1.4 ×106 dpms-1 from the north. Weddell Sea Deep Water (WSDW) leaving the Weddell Gyre northward to form AABW is exposed in the ACC to resuspended opal-rich sediments that act as efficient scavengers with a Th/Pa fractionation factor F ≤ 1. Hydrothermal inputs may provide additional removal with low F. Scavenging in the full meridional circulation across the opal-rich ACC thus acts as a double 231Pa and 230Th trap that preconditions newly formed AABW.

  17. Temporal evolution of (137)Cs, (237)Np, and (239+240)Pu and estimated vertical (239+240)Pu export in the northwestern Mediterranean Sea.

    Science.gov (United States)

    Bressac, M; Levy, I; Chamizo, E; La Rosa, J J; Povinec, P P; Gastaud, J; Oregioni, B

    2017-10-01

    The evolution of (137)Cs, (237)Np and (239+240)Pu at the DYFAMED station (NW Mediterranean) is discussed in relation to physical processes, downward fluxes of particles, and changes in the main input sources. The data set presented in this study represents the first complete (237)Np vertical profiles (0.12-0.27μBqL(-1)), and constitutes a baseline measurement to assess future changes. A similar behavior of Cs and Np has been evidenced, confirming that Np behaves conservatively. While the (137)Cs decrease has been driven by its radioactive decay, the vertical distribution of (237)Np has not substantially changed over the last decade. In the absence of recent major inputs, a homogenization of their vertical distribution occurred, partly due to deep convection events that became more intense during the last decade. In contrast, (239+240)Pu surface levels in the NW Mediterranean waters have fallen in the past four decades by a factor of 5. This decrease in surface has been balanced by higher concentrations in the deep-water layers. A first estimate of the downward (239+240)Pu fluxes in the NW Mediterranean Sea is proposed over more than two decades. This estimation, based on the DYFAMED sediment trap time-series data and published (239+240)Pu flux measurements, suggests that sinking particles have accounted for 60-90% of the upper layer (0-200m) Pu inventory loss over the period 1989-2013. The upper layer residence time of Pu is estimated to be ~28years, twice as long as the residence time estimated for the whole western Mediterranean (~15years). This difference highlights the slow removal of Pu in the open waters of the NW Mediterranean and confirms that most of the Pu removal occurs along the coastal margin where sedimentation rates are high. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Emission probabilities of {gamma}-rays from {sup 238}Np and their use for determination of the thermal neutron capture cross section of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Letourneau, A. [Irfu, CEA-Saclay, 91191 Gif-sur-Yvette (France)], E-mail: aletourneau@cea.fr; Marie, F. [Irfu, CEA-Saclay, 91191 Gif-sur-Yvette (France); Mutti, P. [Institut Laue-Langevin, 38000 Grenoble (France); AlMahamid, I. [Wadsworth Center, Laboratory of Inorganic and Nuclear Chemistry, Albany, NY (United States)

    2010-03-15

    The relevant absolute {gamma}-ray emission probabilities from the {beta}-decay of {sup 238}Np were measured by means of {alpha}- and {gamma}-spectroscopic techniques. We obtained values of (25.6{+-}0.4)%, (8.9{+-}0.2)% and (18.8{+-}0.3)% for the 984.45-, 1025.87- and 1028.54-keV {gamma}-rays, respectively, in agreement with the previous measured ones. These intensities were used to deduce the thermal neutron capture cross section of {sup 237}Np for which a value of (182.2{+-}4.5) b is obtained higher by 11% than the recommended value.

  19. On the sequential separation and quantification of (237)Np, (241)Am, thorium, plutonium, and uranium isotopes in environmental and urine samples.

    Science.gov (United States)

    Vasile, M; Jacobs, K; Bruggeman, M; Van Hoecke, K; Dobney, A; Verrezen, F

    2017-07-13

    The implementation of the one-pass-through separation technique using two stacked chromatography columns of TEVA - TRU resins for the separation of (237)Np, (241)Am, thorium, plutonium and uranium from environmental and urine samples was investigated. The sequential separation technique proved to be successful and gave similar results to those obtained when using individual separations. The analysis time was considerably improved. The amount of chemical waste was also reduced by 50% and the use of HClO4 was avoided. The technique of ICP-MS was also investigated as a complementary technique to alpha-spectrometry. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Sediment 231Pa/230Th as a recorder of the rate of the Atlantic meridional overturning circulation: insights from a 2-D model

    Directory of Open Access Journals (Sweden)

    S. E. Allen

    2010-03-01

    Full Text Available A two dimensional scavenging model is used to investigate the patterns of sediment 231Pa/230Th generated by the Atlantic Meridional Overturning Circulation (AMOC and further advance the application of this proxy for ocean paleocirculation studies. The scavenging parameters and the geometry of the overturning circulation cell have been chosen so that the model generates meridional sections of dissolved 230Th and 231Pa consistent with published water column profiles and an additional 12 previously unpublished profiles measured in the North and Equatorial Atlantic. The processes that generate the meridional sections of dissolved and particulate 230Th, dissolved and particulate 231Pa, dissolved and particulate 231Pa/230Th, and sediment 231Pa/230Th are discussed in detail. The results indicate that the relationship between sediment 231Pa/230Th at any given site and the overturning circulation is very complex. They clearly show that constraining past changes in the strength and geometry of the AMOC requires an extensive data set and they suggest strategies to maximize information from a limited number of samples.

  1. Sediment 231Pa/230Th as a recorder of the rate of the Atlantic meridional overturning circulation: insights from a 2-D model

    Directory of Open Access Journals (Sweden)

    S. E. Allen

    2009-11-01

    Full Text Available A two dimensional scavenging-circulation model is used to investigate the patterns of sediment 231Pa/230Th generated by the Atlantic Meridional Overturning Circulation (AMOC and further advance the application of this proxy for ocean paleocirculation studies. The scavenging parameters and the geometry of the overturning circulation cell have been chosen so that the model generates meridional sections of dissolved 230Th and 231Pa consistent with published water column profiles and an additional 12 previously unpublished profiles measured in the North and Equatorial Atlantic. The processes that generate the meridional sections of dissolved and particulate 230Th, dissolved and particulate 231Pa, dissolved and particulate 231Pa/230Th, and sediment 231Pa/230Th are discussed in detail. The results indicate that the relationship between sediment 231Pa/230Th at any given site and the overturning circulation is very complex. They clearly show that constraining past changes in the strength and geometry of the AMOC requires an extensive data set and they suggest strategies to maximize information from a limited number of samples.

  2. Transmutation of 129I and 237Np using spallation neutrons produced by 1.5, 3.7 and 7.4 GeV protons

    Science.gov (United States)

    Wan, J.-S.; Schmidt, Th.; Langrock, E.-J.; Vater, P.; Brandt, R.; Adam, J.; Bradnova, V.; Bamblevski, V. P.; Gelovani, L.; Gridnev, T. D.; Kalinnikov, V. G.; Krivopustov, M. I.; Kulakov, B. A.; Sosnin, A. N.; Perelygin, V. P.; Pronskikh, V. S.; Stegailov, V. I.; Tsoupko-Sitnikov, V. M.; Modolo, G.; Odoj, R.; Phlippen, P.-W.; Zamani-Valassiadou, M.; Adloff, J. C.; Debeauvais, M.; Hashemi-Nezhad, S. R.; Guo, S.-L.; Li, L.; Wang, Y.-L.; Dwivedi, K. K.; Zhuk, I. V.; Boulyga, S. F.; Lomonossova, E. M.; Kievitskaja, A. F.; Rakhno, I. L.; Chigrinov, S. E.; Wilson, W. B.

    2001-05-01

    Small samples of 129I and 237Np, two long-lived radwaste nuclides, were exposed to spallation neutron fluences from relatively small metal targets of lead and uranium, that were surrounded with a 6 cm thick paraffin moderator, and irradiated with 1.5, 3.7 and 7.4 GeV protons. The (n,γ) transmutation rates were determined for these nuclides. Conventional radiochemical La- and U-sensors and a variety of solid-state nuclear track detectors were irradiated simultaneously with secondary neutrons. Compared with results from calculations with well-known cascade codes (LAHET from Los Alamos and DCM/CEM from Dubna), the observed secondary neutron fluences are larger.

  3. Transmutation of {sup 129}I and {sup 237}Np using spallation neutrons produced by 1.5, 3.7 and 7.4 GeV protons

    Energy Technology Data Exchange (ETDEWEB)

    Wan, J.-S.; Schmidt, T.Th.; Langrock, E.-J.; Vater, P.; Brandt, R. E-mail: brandtr@mailer.uni-marburg.de; Adam, J.; Bradnova, V.; Bamblevski, V.P.; Gelovani, L.; Gridnev, T.D.; Kalinnikov, V.G.; Krivopustov, M.I.; Kulakov, B.A.; Sosnin, A.N.; Perelygin, V.P.; Pronskikh, V.S.; Stegailov, V.I.; Tsoupko-Sitnikov, V.M.; Modolo, G.; Odoj, R.; Phlippen, P.-W.; Zamani-Valassiadou, M.; Adloff, J.C.; Debeauvais, M.; Hashemi-Nezhad, S.R.; Guo, S.-L.; Li, L.; Wang, Y.-L.; Dwivedi, K.K.; Zhuk, I.V.; Boulyga, S.F.; Lomonossova, E.M.; Kievitskaja, A.F.; Rakhno, I.L.; Chigrinov, S.E.; Wilson, W.B

    2001-05-11

    Small samples of {sup 129}I and {sup 237}Np, two long-lived radwaste nuclides, were exposed to spallation neutron fluences from relatively small metal targets of lead and uranium, that were surrounded with a 6 cm thick paraffin moderator, and irradiated with 1.5, 3.7 and 7.4 GeV protons. The (n,{gamma}) transmutation rates were determined for these nuclides. Conventional radiochemical La- and U-sensors and a variety of solid-state nuclear track detectors were irradiated simultaneously with secondary neutrons. Compared with results from calculations with well-known cascade codes (LAHET from Los Alamos and DCM/CEM from Dubna), the observed secondary neutron fluences are larger.

  4. Transmutation of 129I, 237Np, 238Pu, 239Pu, and 241Am using neutrons produced in target-blanket system `Energy plus Transmutation' by relativistic protons

    Indian Academy of Sciences (India)

    J Adam; K Katovsky; A Balabekyan; V G Kalinnikov; M I Krivopustov; H Kumawat; A A Solnyshkin; V I Stegailov; S G Stetsenko; V M Tsoupko-Sitnikov; W Westmeier

    2007-02-01

    Target-blanket facility `Energy + Transmutation' was irradiated by proton beam extracted from the Nuclotron Accelerator in Laboratory of High Energies of Joint Institute for Nuclear Research in Dubna, Russia. Neutrons generated by the spallation reactions of 0.7, 1.0, 1.5 and 2 GeV protons and lead target interact with subcritical uranium blanket. In the neutron field outside the blanket, radioactive iodine, neptunium, plutonium and americium samples were irradiated and transmutation reaction yields (residual nuclei production yields) have been determined using -spectroscopy. Neutron field's energy distribution has also been studied using a set of threshold detectors. Results of transmutation studies of 129I, 237Np, 238Pu, 239Pu and 241Am are presented.

  5. [The action of 232Th separately and in combination with heavy and alkaline metal salts on Tradescantia (clone 02)].

    Science.gov (United States)

    Evseeva, T I; Geras'kin, S A

    2000-01-01

    The action of 232Th-nitrate in concentration 0.09, 0.18 and 0.36 mg/l (counting on 232Th ion) on water cultures of Tradescantia (clone 02) was investigated. It was found that all investigated concentrations of 232Th showed statistically significant genotoxic effect and increased level of morphological abnormal cells in the stamen hairs of Tradescantia in the absence of modifying action of other metal ions. Synergistic toxic interaction was found between the 232Th in concentration 0.18 mg/l and metal ions for all samples of thawed water. Synergistic genotoxic effect of the combined action of these factors was revealed only at the low total contents of ions of heavy and alkaline metals in thawed water samples. The observed synergistic effects of the combined action of 232Th and metal ions should be taken into account when controlling the radionuclide level in the environment.

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

    Indian Academy of Sciences (India)

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

    2012-08-01

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

  7. Excitation energy dependence of fragment characteristics for the photofission of 232Th

    Science.gov (United States)

    Persyn, K.; Jacobs, E.; Pommé, S.; De Frenne, D.; Govaert, K.; Yoneama, M. L.

    1997-02-01

    Independent and cumulative product yields were measured for the photofission of 232Th with bremsstrahlung with endpoint energies 6.5, 7.0, 8.0, 11.0, 12.0, and 14.0 MeV, applying γ spectrometric techniques on catcherfoils and pneumatically transported 232Th-samples. The independent heavy fragment yields for the fission of the 232Th compound nucleus at excitation energies in the vicinity of the fission barrier were deduced. Postneutron mass, isobaric charge, isotopic mass distributions, isotonic and elemental yield distributions and proton odd-even effects were obtained from these independent yields. In the mass distributions a maximum yield is observed for mass splits with heavy fragments in the region of A = 142, corresponding with a high production of Ba( Z = 56) - isotopes. A slightly increased yield is also observed for mass splits with heavy mass in the vicinity of A = 134. The latter effect increases with increasing compound nucleus excitation energy. The similarity between the mass distributions of the N = 142 fissioning systems 232Th, 234U and 236Pu is striking. For low excitation energy the proton odd-even effect in the element distributions amounts to 30%, while on the other hand no sizeable neutron odd-even effect could be deduced from the isotonic distributions. The proton odd-even effects remain constant up to compound nucleus excitation energies of about 7.85 MeV. For higher compound nucleus excitation energies the proton odd-even effect drops rapidly. A possible explanation of these observations in terms of pair breaking at the outer barrier is proposed.

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

    Science.gov (United States)

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

    2016-06-01

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

  9. 232Th, 233Pa, and 234U capture cross-section measurements in moderated neutron flux

    Science.gov (United States)

    Bringer, O.; Isnard, H.; AlMahamid, I.; Chartier, F.; Letourneau, A.

    2008-07-01

    The Th-U cycle was studied through the evolution of a 100 μg 232Th sample irradiated in a moderated neutron flux of 8.010 14 n/cm 2/s, intensity close to that of a thermal molten salt reactor. After 43 days of irradiation and 6 months of cooling, a precise mass spectrometric analysis, using both TIMS and MC-ICP-MS techniques, was performed, according to a rigorous methodology. The measured thorium and uranium isotopic ratios in the final irradiated sample were then compared with integral simulations based on evaluated data; an overall good agreement was seen. Four important thermal neutron-capture cross-sections were also extracted from the measurements, 232Th (7.34±0.21 b), 233Pa (38.34±1.78 b), 234U (106.12±3.34 b), and 235U (98.15±11.24 b). Our 232Th and 235U results confirmed existing values whereas the cross-sections of 233Pa and 234U (both key parameters) have been redefined.

  10. 230Th and 231Pa on GEOTRACES GA03, the U.S. GEOTRACES North Atlantic transect, and implications for modern and paleoceanographic chemical fluxes

    Science.gov (United States)

    Hayes, Christopher T.; Anderson, Robert F.; Fleisher, Martin Q.; Huang, Kuo-Fang; Robinson, Laura F.; Lu, Yanbin; Cheng, Hai; Edwards, R. Lawrence; Moran, S. Bradley

    2015-06-01

    The long-lived uranium decay products 230Th and 231Pa are widely used as quantitative tracers of adsorption to sinking particles (scavenging) in the ocean by exploiting the principles of radioactive disequilibria. Because of their preservation in the Pleistocene sediment record and through largely untested assumptions about their chemical behavior in the water column, the two radionuclides have also been used as proxies for a variety of chemical fluxes in the past ocean. This includes the vertical flux of particulate matter to the seafloor, the lateral flux of insoluble elements to continental margins (boundary scavenging), and the southward flux of water out of the deep North Atlantic. In a section of unprecedented vertical and zonal resolution, the distributions of 230Th and 231Pa across the North Atlantic shed light on the marine cycling of these radionuclides and further inform their use as tracers of chemical flux. Enhanced scavenging intensities are observed in benthic layers of resuspended sediments on the eastern and western margins and in a hydrothermal plume emanating from the Mid-Atlantic Ridge. Boundary scavenging is clearly expressed in the water column along a transect between Mauritania and Cape Verde which is used to quantify a bias in sediment fluxes calculated using 230Th-normalization and to demonstrate enhanced 231Pa removal from the deep North Atlantic by this mechanism. The influence of deep ocean ventilation that leads to the southward export of 231Pa is apparent. The 231Pa/230Th ratio, however, predominantly reflects spatial variability in scavenging intensity, complicating its applicability as a proxy for the Atlantic meridional overturning circulation.

  11. Determination of 232Th in urine by ICP-MS for individual monitoring purposes.

    Science.gov (United States)

    Baglan, N; Cossonnet, C; Ritt, J

    2001-07-01

    Thorium is naturally occurring in various ores used for industrial purposes and has numerous applications. This paper sets out to investigate urine analysis as a suitable monitoring approach for workers potentially exposed to thorium. Due to its biokinetic behavior and its low solubility, urinary concentrations are generally very low, requiring therefore high sensitivity analytical methods. An analytical procedure has been developed for detecting 232Th concentrations of below 1 mBq L(-1) quickly and easily. Due to the long half-life (1.41 x 10(10) y) of 232Th, the potential of a procedure based on urine sample dilution and ICP-MS (inductively coupled plasma-mass spectrometry) measurement was investigated first. Two dilution factors were chosen: 100, which is more suitable for long-term measurement trials, and 20, which increases sensitivity. It has been shown that a 100-fold dilution can be used to measure concentrations of below 1 mBq L(-1), whereas a 20-fold one can be used to reach concentrations of below 0.06 mBq L(-1). Then, on the basis of the limitation of the procedure based on urine dilution, the suitable field of application for the different procedures (100-fold and 20-fold dilution and also a chemical purification followed by an ICP-MS measurement) was determined in relation to monitoring objectives.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-08-01

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

  13. The low-energy dipole structure of 232Th , 236U and 238U actinide nuclei

    Science.gov (United States)

    Kuliev, A. A.; Guliyev, E.; Ertugral, F.; Özkan, S.

    2010-03-01

    In this study, ensuremath I^{π} = 1+ and ensuremath I^{π} = 1- dipole mode excitations are systematically investigated within the rotational and translational + Galilean invariant quasiparticle random-phase approximation for 232Th , 236U , and 238U actinide nuclei. It is shown that the investigated nuclei reach a B( M1) strength structure, which corresponds to the scissors mode. The calculated mean excitation energies as well as the summed B( M1) value of the scissors mode excitations are consistent with the available experimental data. The results of calculations indicate large differences to the rare-earth nuclei as is the case for the experiment: a doubling of the observed dipole strengths and a shift of the energy centroid to the lower energies by about 800keV. The calculations indicate the presence of a few prominent negative-parity ensuremath K^{π} = 1- states in the 2.0-4.0MeV energy interval. The occurrence of the negative-parity dipole states with the rather high B( E1) value less than 4MeV shows the necessity of explicit parity measurements for the correct determination of the scissors mode strength in 232Th , 236U , and 238U isotopes.

  14. Natural Activities of 238U, 232Th and 40K in Manganese Ore

    Directory of Open Access Journals (Sweden)

    H. A. Abel-Ghany

    2010-01-01

    Full Text Available Problem statement: Manganese ore is widely used in much industries. Such as ore contain natural radioactive nuclides at various concentrations. If this ore contain high concentrations of natural radioactive nuclides, workers handling them might be exposed to significant levels of radiation. Therefore it is important to determine the radioactive nuclides in this ore. Approach: The natural radionuclides (238U, 232Th and 40K contents of Manganese ore samples collected by Siani Manganese Company in Egypt-Cairo have been determined by low background spectroscopy using hyper-pure germanium (HPGe detector. Results: The mean activities due to the three radionuclides (238U, 232Th and40K were found to be 3543±106, 222±6.6 and 3483±104 Bqkg-1, respectively. The absorbed dose rate due to the natural radioactivity in samples under investigation ranged from 1522±45-1796±53 nGyh-1. The radium equivalent activity varied from 3807±114-4446±133 Bqkg-1. The representative external hazard index values for the corresponding samples are also estimated. Conclusion: The results of this assessment obtained by the gamma-ray spectroscopic analysis, have indicated that the levels of natural radioactivity were higher than the international recommended limits.

  15. 232Th-228Ra-228Th Recording of Estuarine and Coastal Sedimentological Events

    Science.gov (United States)

    Hillaire-Marcel, C.; Ghaleb, B.; Ruiz-Fernandez, A.

    2011-12-01

    Climatic events (e.g., storminess, floods) and river/coastal management activities (e.g., dredging) may result in the removal and re-suspension of contaminated sediments in shallow coastal areas and estuaries, thus leading to long-term contamination of such environments. Short-lived daughter isotopes of 232Th (228Ra-228Th) in sediments may then provide some quantitative assessment of the amount of material removed/re-deposited as well as some indications on the chronology of causal events. Examples from the Gulf of St. Lawrence (GSL) and the Pacific coastal rea of Mexico (PcM) are used to illustrate such isotopic responses to natural or anthropogenic disturbances. In the GSL relatively steady accumulation processes are usually observed, although sedimentary sequences show variable benthic mixing patterns over a large array of sedimentation rates (from mm/a to cm/a). In undisturbed sequences, 232Th-daughter isotopes in particulate matter show strong disequilibria due i) to 228Ra-diffusion/228Th adsorption in source-soils and during particulate transport, ii) 228Ra-behavior at the water column/sea-floor interface. Core-top sediments thus depict a strong excess in 228Th vs. 232Th. Below, a fast return (within ~ 10 a) of 228Th to equilibrium with its parent 228Ra leads to a 228Th deficit vs 232Th, in response to 228Ra-losses and diffusion towards the water column. Deeper, a return to full equilibrium conditions is observed (~ 30 a), but for "non-local mixing" events. Few disturbances are observed in the area. They include nearly cyclic pulses in 210Pb at the head of the Laurentian Trough, which we attribute to dredging operations of the St. Lawrence Sea-Way, and in the sealing of Hg-contaminated sediments in the Saguenay Fjord, by flood layers. Comparatively most sequences cored in estuarine settings of the PcM illustrate more critical situations with respect to the re-suspension of sediments, which are often contaminated due to land management and industrial practices

  16. 238 U, 232 Th and 40 K in wheat flour samples of Iraq markets

    Directory of Open Access Journals (Sweden)

    A. A.

    2014-09-01

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

  17. 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.

  18. Investigating the use of 232Th/230Th as a dust proxy using co-located seawater and sediment samples from the low-latitude North Atlantic

    Science.gov (United States)

    Rowland, George H.; Ng, Hong Chin; Robinson, Laura F.; McManus, Jerry F.; Mohamed, Kais J.; McGee, David

    2017-10-01

    The thorium isotope ratio 232Th/230Th can be measured in seawater and sediment samples, and has been used as a proxy to reconstruct lithogenic fluxes to the oceans for the modern day and the Pleistocene. There has not yet been a systematic study testing the proxy using the 232Th/230Th ratio in seawater and the ratio recorded in the underlying sediment. In this study we use co-located core-top sediments and seawater samples from five seamount sites spanning the tropical North Atlantic to investigate the link between seawater and sediment 232Th/230Th ratios across a range of water depths. Our results indicate that a broad correlation exists between seawater and sedimentary 232Th/230Th ratios. Both seawater and sedimentary 232Th/230Th ratios record a signal consistent with decreasing lithogenic input east to west, from Africa to South America. However, calculated 232Th fluxes for the core-top sediment samples indicate a strong dependence on depth, with up to a factor of ∼4 difference from shallow (2900 m). This depth dependence is likely caused by either a deficit of 230Th burial at depth compared to the production in the overlying water column, through addition of 232Th, or by a combination of the two. By comparing seawater and sedimentary 232Th/230Th ratios we derive an apparent fractional solubility of 232Th of 29 ± 3%, in reasonable agreement with the upper end of existing estimates.

  19. Transfer factor of 226Ra, 232Th and 40K from soil to Alpinia Galangal plant grown in northern Thailand

    Science.gov (United States)

    Kritsananuwat, R.; Chanyotha, S.; Kranrod, C.; Pengvanich, P.

    2017-06-01

    This paper reports the activity concentration of three natural radionuclides, 226Ra, 232Th and 40K, found in Alpinia Galangal plants which are widely used in various Asian cuisines and traditional medicine. The galangal plants and their relevant soils were collected from four provinces in the north of Thailand under natural field conditions. The activity concentration of radionuclides was determined using gamma-ray spectrometry. Soil-to-plant transfer factors (TFs) for 226Ra, 232Th and 40K were investigated in rhizome and aerial parts of the galangal plants. The activity concentration in the soils ranged from 22 to 88 Bq kg-1 for 226Ra, 27 to 157 Bq kg-1 for 232Th and 58 to 1157 Bq kg-1 for 40K. In Alpinia Galangal, the concentration ranged from natural radionuclides and their TFs in Thailand for future environmental radiation monitoring. The Annual effective ingestion dose due to ingestion of 226Ra, 232Th and 40K in galangals is significantly below the worldwide value reported by UNSCEAR 2000.

  20. High resolution measurement of the /sup 231/Pa(n,f) cross section from 0. 4 eV to 12 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Plattard, S; Auchampaugh, G F; de Saussure, G

    1980-01-01

    The /sup 231/Pa(n,f) reaction was studied to shed light on the existence of a shallow third minimum in the /sup 232/Pa fission barrier. Results are plotted along with data points derived from ENDF/B-V. The occurrence of a pure vibrational state at E/sub n/ = 156.7 keV (3/sup +/) together with a nearby state of opposite parity favors the evidence for a third asymmetrically deformed minimum in the /sup 232/Pa fission barrier. 2 figures. (RWR)

  1. Projectile-breakup-induced fission-fragment angular distributions in the 6Li+232Th reaction

    Science.gov (United States)

    Pal, A.; Santra, S.; Chattopadhyay, D.; Kundu, A.; Ramachandran, K.; Tripathi, R.; Roy, B. J.; Nag, T. N.; Sawant, Y.; Sarkar, D.; Nayak, B. K.; Saxena, A.; Kailas, S.

    2017-08-01

    Background: Experimental anisotropy in fission-fragment (FF) angular distribution in reactions involving weakly bound stable projectiles with actinide targets are enhanced compared to statistical saddle-point model (SSPM) predictions. Contributions from breakup- or transfer-induced fission to total fission are cited as possible reasons for such enhancement. Purpose: To identify the breakup- or transfer-induced fission channels in 6Li+232Th reaction and to investigate their effects on FF angular anisotropy. Methods: The FF angular distributions have been measured exclusively at three beam energies (28, 32, and 36 MeV) around the Coulomb barrier in coincidence with projectile breakup fragments like α , d , and p using Si strip detectors. The angular anisotropy obtained for different exclusive breakup- or transfer-induced fission channels are compared with that for total fission. SSPM and pre-equilibrium fission models have been employed to obtain theoretical FF angular anisotropy. Results: Angular anisotropy of the fission fragments produced by different transfer- or breakup-induced fission reactions have been obtained separately in the rest frame of respective recoiling nuclei. Some of these anisotropies were found to be stronger than those of the inclusive fission. Overall angular distributions of transfer or breakup fission, integrated over all possible recoil angles with weight factor proportional to differential cross section of the complementary breakup fragment emitted in coincidence in all possible directions, were obtained. It was observed that the overall FF angular anisotropy for each of these fission channels is less than or equal to the anisotropy of total fission at all the measured energies. Assuming isotropic out-of-plane correlations between the fission fragments and light-charged particles, the overall breakup- or transfer-induced fission fragment angular distributions do not explain the observed enhancement in FF anisotropy of total fission. Pre

  2. Measurement of the Neutron Capture Cross Sections of $^{233}$U, $^{237}$Np, $^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm with a Total Absorption Calorimeter at n_TOF

    CERN Multimedia

    Beer, H; Wiescher, M; Cox, J; Rapp, W; Embid, M; Dababneh, S

    2002-01-01

    Accurate and reliable neutron capture cross section data for actinides are necessary for the poper design, safety regulation and precise performance assessment of transmutation devices such as Fast Critical Reactors or Accelerator Driven Systems (ADS). The goal of this proposal is the measurement of the neutron capture cross sections of $^{233}$U, $^{237}$Np, $^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm at n_TOF with an accuracy of 5~\\%. $^{233}$U plays an essential role in the Th fuel cycle, which has been proposed as a safer and cleaner alternative to the U fuel cycle. The capture cross sections of $^{237}$Np,$^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm play a key role in the design and optimization of a strategy for the Nuclear Waste Transmutation. A high accuracy can be achieved at n_TOF in such measurements due to a combination of features unique in the world: high instantaneous neutron fluence and excellent energy resolution of the facility, innovative Data Acquisition System based on flash ADCs and t...

  3. Study of 232Th(n, γ) and 232Th(n,f) reaction rates in a graphite moderated spallation neutron field produced by 1.6 GeV deuterons on lead target

    Science.gov (United States)

    Asquith, N. L.; Hashemi-Nezhad, S. R.; Westmeier, W.; Zhuk, I.; Tyutyunnikov, S.; Adam, J.

    2015-02-01

    The Gamma-3 assembly of the Joint Institute for Nuclear Research (JINR), Dubna, Russia is designed to emulate the neutron spectrum of a thermal Accelerator Driven System (ADS). It consists of a lead spallation target surrounded by reactor grade graphite. The target was irradiated with 1.6 GeV deuterons from the Nuclotron accelerator and the neutron capture and fission rate of 232Th in several locations within the assembly were experimentally measured. 232Th is a proposed fuel for envisaged Accelerator Driven Systems and these two reactions are fundamental to the performance and feasibility of 232Th in an ADS. The irradiation of the Gamma-3 assembly was also simulated using MCNPX 2.7 with the INCL4 intra-nuclear cascade and ABLA fission/evaporation models. Good agreement between the experimentally measured and calculated reaction rates was found. This serves as a good validation for the computational models and cross section data used to simulate neutron production and transport of spallation neutrons within a thermal ADS.

  4. Analyses of β-Bands of 230,232Th and 232,234U by the Projected Shell Model

    Institute of Scientific and Technical Information of China (English)

    CUI Ji-Wei; ZHOU Xian-Rong; CHEN Fang-Qi; SUN Yang; WU Cheng-Li

    2012-01-01

    The ground bands and β-bands of four nuclei 230,232Th and 232,234U in the actinide region are investigated by introducing a collective Do pair into the projected shell model.We discuss the collectivity of the Do pair.The calculated energy schemes agree well with experimental data,and so do the E2 transition rates.%The ground bands and β-bands of four nuclei 230,232 Th and 232,234 U in the actinide region are investigated by-introducing a collective Do pair into the projected shell model. We discuss the collectivity of the D0 pair. The calculated energy schemes agree well with experimental data, and so do the E2 transition rates.

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

    Science.gov (United States)

    Perevolotskiĭ, A N; Perevolotskaia, T V

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Xin Wang

    2015-09-01

    Full Text Available The naturally occurring primordial radionuclides in coals might exhibit high radioactivity, and can be exported to the surrounding environment during coal combustion. In this study, nine coal samples were collected from eastern Yunnan coal deposits, China, aiming at characterizing the overall radioactivity of some typical nuclides (i.e., 40K, 238U, 232Th, 226Ra and assessing their ecological impact. The mean activity concentrations of 238U, 232Th, 40K and 226Ra are 63.86 (17.70–92.30 Bq· kg-1, 23.76 (11.10–37.10 Bq· kg-1, 96.84 (30.60–229.30 Bq· kg-1 and 28.09 Bq·kg-1 (3.10–61.80 Bq·kg-1, respectively. Both 238U and 232Th have high correlations with ash yield of coals, suggesting their inorganic origins. The overall environmental effect of natural radionuclides in studied coals is considered to be negligible, as assessed by related indexes (i.e., radium equivalent activity, air-adsorbed dose rate, annual effective dose, and external hazard index. However, the absorbed dose rates values are higher than the average value of global primordial radiation and the Chinese natural gamma radiation dose rate.

  7. Solubility assessment of 232Th from various types of soil in Malaysia using USP and DIN In Vitro digestion method

    Science.gov (United States)

    Rashid, Nur Shahidah Abdul; Perama, Yasmin Mohd Idris; Salih, Fitri Hakeem Mohd; Sarmani, Sukiman; Majid, Amran Ab.; Siong, Khoo Kok

    2016-11-01

    The overall results of the study showed that the concentrations of 232Th radionuclide using DIN digestion method during gastric phase are 0.0015 mg/kg - 0.0554 mg/kg and 0.0015 mg/kg - 0.0139 mg/kg during intestinal phase, respectively. As for USP digestion method during gastric phase are between 0.0877 mg/kg - 0.4964 mg/kg and 0.0207 mg/kg - 0.2291 mg/kg. The results from the measurements in various types of soils indicates some elevation of 232Th concentration in some types of soil compared to UNSCEAR reference values, in which may be a result from the impact of previous mining activity in the surrounding area and considered to be safe. In general, the results of 232Th concentrations from in vitro extraction technique is considered to be safe. By natural processes, thorium ingestion is getting transferred to living beings through different pathways and need to be monitored in order to assess possible hazards. Environmental studies are generally carried out to trace the pathway of radionuclides/radiotoxic elements to reach living organism. Environmental monitoring and meaningful interpretation of data from man-made pollution are more complicated without adequate knowledge about the natural abundance of radioactive elements in the environment.

  8. Investigation of Neutron Spectra and Transmutation of ^{129}I, ^{237}Np and Other Nuclides with 1.5 GeV Protons from the Dubna Nuclotron Using the Electronuclear Setup "Energy plus Transmutation"

    CERN Document Server

    Krivopustov, M I; Balabekyan, A R; Batusov, Yu A; Bielewicz, M; Brandt, R; Chaloun, P; Chultem, D; Dwivedi, K K; Elishev, A F; Fragopoulou, M; Henzl, V; Henzlová, D; Kalinnikov, V G; Kievets, M K; Krása, A; Krizek, F; Kugler, A; Manolopoulou, Metaxia; Mariin, I I; Nourreddine, A; Odoj, R; Pavliouk, A V; Pronskikh, V S; Robotham, H; Siemon, K; Szuta, M; Stegailov, V I; Solnyshkin, A A; Sosnin, A N; Stoulos, S; Tsoupko-Sitnikov, V M; Tumendelger, T; Wojecehowski, A; Wagner, V; Wan, J S; Westmeier, W; Zamani-Valasiadou, M; Kumawat, H; Kumar, V; Zaverioukha, O S; Zhuk, I V

    2004-01-01

    Experiments which are part of the scientific program "Investigations of physical aspects of electronuclear method of energy production and transmutation for radioactive waste of atomic energetics using relativistic beams from the JINR Synchrophasotron/Nuclotron" (project "Energy plus Transmutation") are described. A large lead target surrounded by a four-section uranium blanket with total weight of 206.4 kg natural uranium was irradiated with 1.5 GeV protons from the new cryogenic accelerator Nuclotron. Radiochemical sensors were exposed to the secondary particle fluences inside and on top of the target assembly. Two long-lived radioactive waste of atomic energetics sensors ^{129}I and ^{237}Np (approximately 1 g weight each) and stable nuclides ^{27}Al, ^{59}Co, ^{127}I, ^{139}La, ^{197}Au and ^{209}Bi as well as natural and enriched uranium were used. In addition, various solid state nuclear track detectors and nuclear emulsions were exposed simultaneously. The experimental results confirm the theoretical e...

  9. Annual committed effective dose from olive oil (due to 238U, 232Th, and 222Rn) estimated for members of the Moroccan public from ingestion and skin application.

    Science.gov (United States)

    Misdaq, M A; Touti, R

    2012-03-01

    Olive oil is traditionally refined and widely consumed by Moroccan rural populations. Uranium (238U), thorium (232Th), radon (222Rn), and thoron (220Rn) contents were measured in various locally produced olive oil samples collected in rural areas of Morocco. These radionuclides were also measured inside various bottled virgin olive oils consumed by the Moroccan populations. CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs) were used. Annual committed effective doses due to 238U, 232Th, and 222Rn from the ingestion of olive oil by the members of the general public were determined. The maximum total committed effective dose due to 238U, 232Th, and 222Rn from the ingestion of olive oil by adult members of Moroccan rural populations was found equal to 5.9 µSv y-1. The influence of pollution due to building material dusts and phosphates on the radiation dose to workers from the ingestion of olive oil was investigated, and it was found that the maximum total committed effective dose due to 238U, 232Th, and 222Rn was on the order of 0.22 mSy y-1. Committed effective doses to skin due to 238U, 232Th, and 222Rn from the application of olive oil masks by rural women were evaluated. The maximum total committed effective dose to skin due to 238U, 232Th, and 222Rn was found equal to 0.07 mSy y-1 cm-2.

  10. Determination of {sup 238}U and {sup 232}Th in geological samples by alpha and gamma spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Emerson E.G. de; Hazin, Clovis A., E-mail: chazin@cnen.gov.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Honorato, Eliane V.; Franca, Elvis J. De, E-mail: valentim@cnen.gov.br, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2011-07-01

    Alpha and gamma spectrometry are analytical techniques of great importance for the determination of natural radionuclides, especially for radioisotopes of the {sup 238}U and {sup 232}Th series. Due to the presence of completely different chemical elements in these series, with different gamma-ray abundances and decay branches, it is quite relevant to define consistent analytical approaches to be adopted in an environmental analysis routine basis. For the establishment of such protocol for the radiometric analysis of geological samples routinely analyzed in the Environmental Monitoring Division of the Northeastern Regional Center for Nuclear Sciences (CRCN-NE), reference materials of different geologic matrices prepared by the International Atomic Energy Agency - IAEA were analyzed through high resolution gamma-ray spectrometry by means of a Hyper Pure Germanium (HPGe) detector and high resolution alpha spectrometry using a surface barrier detector. Test portions of 2.5 g (for alpha analysis) and 50.0 g (for gamma analysis) of the reference materials IAEA-312 (soil), IAEA-314 (stream sediment), IAEA-375 (soil), and IAEA-135 (sea sediment) were analyzed. The concordance between the obtained values and the reference values for the specific activities of {sup 238}U and {sup 232}Th determined in the certified materials was considered quite satisfactory for both analytical techniques, since the relative errors were lower than 20 %, except for the results of gamma spectrometry using the line 93 keV, in which interference from the 93,35 keV gamma line of {sup 228}Ac (from the {sup 232}Th series) was detected. The results indicated a good degree of comparability for the radiometric analysis of geological samples. (author)

  11. Measurement of the fission fragment angular distribution for 232Th(n,f) at the CERN n-TOF facility

    CERN Document Server

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

    2012-01-01

    A fission reaction chamber was designed to measure the angular distribution of the fragments emitted in neutron-induced fission reactions at n_TOF. Up to ten Parallel Plate Avalanche Counters can be included and kept at controlled low-pressure gas. Counters are tilted 45º with respect to the neutron beam direction and up to nine targets can be interleaved in between. A first measurement of the 232Th(n,f) was recently done and preliminary experimental results demonstrating the suitability of the setup are presented here.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-06-15

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

  13. 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)

  14. 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.

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

    Science.gov (United States)

    Badhan, K; Mehra, R

    2012-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, Reginaldo R.; Pecequilo, Brigitte R.S., E-mail: raquino@ipen.b, E-mail: brigitte@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Gerencia de Metrologia das Radiacoes

    2009-07-01

    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 {sup 226}Ra, {sup 232}Th and {sup 4}0{sup 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 {sup 238}U and {sup 232}Th series. All samples were measured by high resolution gamma spectrometry and the spectra were analyzed with the WinnerGamma software. The {sup 232}Th concentration was determined from the average concentrations of {sup 228}Ac, {sup 212}Pb and {sup 212}Bi and the {sup 226}Ra concentration was determined from the average concentrations of {sup 214}Pb and {sup 214}Bi. Preliminary results show concentrations varying from 9 Bq.kg{sup -1} to 6035 Bq.kg{sup -1} for {sup 232}Th, from 4 Bq.kg{sup -1} to 575 Bq.kg{sup -1} for {sup 226}Ra and from 13 Bq.kg{sup -1} to 142 Bq.kg{sup -1} for {sup 40}K. Areia Preta beach shows the highest values for {sup 232}Th, while the highest value for {sup 226}Ra was observed for Camburi beach. High values of {sup 40}K were observed for Curva da Jurema beach. (author)

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

    Directory of Open Access Journals (Sweden)

    Antović Nevenka M.

    2009-01-01

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

  18. Distribution of 226Ra, 232Th and 40K in soils and sugar cane crops at Corumbataí river basin, São Paulo State, Brazil.

    Science.gov (United States)

    da Conceição, Fabiano Tomazini; Bonotto, Daniel Marcos; Jiménez-Rueda, Jairo Roberto; Roveda, José Arnaldo Frutuoso

    2009-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Thakur Meenu

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Čučulović Ana

    2014-01-01

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

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

    CERN Document Server

    Malins, Alex; Saito, Kimiaki

    2015-01-01

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

  2. Partitioning of 232Th, 230Th and 228Th in the Surface Water of Northwest Peninsular Malaysia Coastal Waters as Tracer for SPM Sources

    Directory of Open Access Journals (Sweden)

    Nor Faizah MMK Noorulhudha

    2017-07-01

    Full Text Available Natural thorium radioisotopes (232Th, 230Th, 228Th, 234Th are well known to be particle reactive, thus they are often used to study the geochemical process of particle reactive matter. In this study, water samples were collected from Langkawi Island and Pangkor Island from six and ten sampling stations respectively, to determine the activity of 232Th, 230Th and 228Th in dissolved (DISS and suspended particulate matter (SPM phases, and estimate the sources and origin of SPM into the marine environment. The results in terms of volume activity concentration (mBq/L shows that the activity level of 228ThDISS was higher than 228ThSPM at all sampling stations possibly due to the behaviour of the 228Th parent, 228Ra which is easily desorbed from SPM. At several stations far from the coast; stations L4 (4.58km, P7 (3.16 km, P6 (2.1 km, P10 (1.38 km, the activity of 232ThDISS was higher compared to 232ThSPM. These stations behave the same way as the open ocean in which 232ThDISS is contributed by atmospheric dust. Indeed, the partition of thorium between dissolved and SPM phase can be used to detect anthropogenic organic pollution as in station L6 in which thorium activity in dissolved phase is higher compared to in SPM phase. Moreover, the use of the (232Th/230ThSPM ratio is useful to detect lithogenic input to the marine environment in which the ratio ranges from 0.13 to 0.5 and 0.7 to 3.16 for stations that are far and near to the coast respectively, except for station P1. However the data analysis shows that there is no clear pattern of kd values at both sampling sites, probably due to the adsorption and desorption processes of 232Th and 230Th that occurs in the water column. Nevertheless, as the SPM concentration (mg/L increases, the kd value decreases except for the activity of 228Th which shows a strong negative correlation with SPM.

  3. 226Ra, 232Th and 40K ACTIVITY CONCENTRATIONS AND RADIOLOGICAL HAZARDS OF BUILDING MATERIALS IN MUGLA, TURKEY

    Directory of Open Access Journals (Sweden)

    Ezgi Eren Belgin

    2015-11-01

    Full Text Available The activity concentrations of natural gamma-emitting radionuclides in commonly used building materials were measured by using high purity germanium (HPGe detector coupled with a high resolution multichannel analyser. The results associated radiation hazards due to  40K, 226Ra and 232Th have been determined in samples collected randomly from southwest part of Turkey. When the building materials such as clay brick, marble, cement etc. originating from soil and rocks are used in constructions they cause direct ionizing radiation exposure at varying intensities. Different criterion formulas as radium equivalent activity, the external/internal hazard indices, the alpha/gamma indexes and the absorbed dose rate in indoor air were determined to assess the radiation hazards arising due to the use of materials studied for people living in the construction of dwellings made of the these materials. Although indoor absorbed dose rate is relatively higher than the world population-weighted average value and international limit for studied brick and cement samples they could be used safely as building materials because radium equivalent activity, alpha/gamma indices and hazard indices of those materials have been found to be within the recommended limits. All the values for all criterion formulas for marble samples are found to be well below the safety limits recommended by UNSCEAR. It can be concluded that examined materials can be used for construction of buildings for interior and external works.

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

    Science.gov (United States)

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

    2016-10-01

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

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-06-15

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

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

    Science.gov (United States)

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

    2016-08-01

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

  8. 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. Fission product yield distribution in the 12, 14, and 16 MeV bremsstrahlung-induced fission of {sup 232}Th

    Energy Technology Data Exchange (ETDEWEB)

    Naik, H. [Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai (India); Kyungpook National University, Department of Physics and Center for High Energy Physics, Daegu (Korea, Republic of); Kim, G.N.; Kim, K. [Kyungpook National University, Department of Physics and Center for High Energy Physics, Daegu (Korea, Republic of); Schwengner, R.; John, R.; Massarczyk, R.; Junghans, A.; Wagner, A. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Goswami, A. [Bhabha Atomic Research Centre, Radiochemistry Division, Mumbai (India)

    2015-11-15

    The absolute cumulative yields of various fission products in the 12, 14, and 16 MeV bremsstrahlung-induced fission of {sup 232}Th were determined using a recoil catcher and an off-line γ -ray spectrometric technique using the ELBE electron linac of Helmholtz-Zentrum Dresden-Rossendorf in Dresden, Germany. The mass chain yields were obtained from the absolute cumulative yields by correcting the charge distribution. The peak-to-valley ratio, average light mass (left angle A{sub L} right angle) and heavy mass (left angle A{sub H} right angle) values, and average number of neutrons (left angle n right angle {sub exp}) in the bremsstrahlung-induced fission of {sup 232}Th at different excitation energies were obtained from the mass chain yield data. The present study and existing literature data for the {sup 232}Th(γ, f) reaction are compared with similar data for the {sup 238}U(γ, f) reaction at various excitation energies, and surprisingly different behavior was found in the two fissioning systems. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-01

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

  11. Activity concentration, transfer factors and resultant radiological risk of 226Ra, 232Th, and 40K in soil and some vegetables consumed in Selangor, Malaysia

    Science.gov (United States)

    Solehah, A. R.; Yasir, M. S.; Samat, S. B.

    2016-11-01

    The activity concentrations of the natural radionuclides 226Ra, 232Th, and 40K were determined in vegetable crops consumed by Malaysian people in Sungai Besar, Selangor. Sample of vegetables and the soil where the crops were cultivated and collected at five different location. The activity concentrations in Bq/kg of 226Ra, 232Th, and 40K were measured by the gamma-ray spectroscopy using the high purity germanium detector. The range activity concentration in soil is between 51.81 and 71.84 Bq/kg, 64.18 and 78.00 Bq/kg, and 210.49 and 244.29 Bq/kg for 226Ra, 232Th, and 40K, respectively. The activity concentration of 226Ra, 232Th, and 40K in vegetables were found to be in the range of 2.06 to 5.44 Bq/kg, Not Detectable to 0.61 Bq/kg, and 101.00 to 1223.09 Bq/kg, respectively. The activity concentration in both soil and vegetables were all less than lower limit stated by UNSCEAR. The Transfer Factors range value for 226Ra, 232Th, and 40K varied from 0.02 to 0.06, 0.003 to 0.008, and 1.79 to 5.19 respectively. Radium equivalent for soil range from 165.57 to 194.84 Bq/kg. It was within the international accepted value (370 Bq/kg). Absorb dose rate for soil range between 73.5 to 86.40 nGyh-1, in safe range from limit of international accepted value (55nGyh-1). Effective dose rate is found to be in range of 0.09 to 0.11 mSvy-1 for soil which is less than 2.4 mSv/y. External and Internal Hazard indices of soil was all below 1, within agreement of other researcher and UNSCEAR. The estimation of the consequent radiological risk due to the presence of those radionuclides is significantly low.

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

    Energy Technology Data Exchange (ETDEWEB)

    Krakowski, R.A.

    1995-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Todorovik Aleksandra

    2012-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  15. 238U and 232Th series nuclides in groundwater from the J-13 well at the Nevada Test Site: Implications for ion retardation

    Science.gov (United States)

    Copenhaver, Sally A.; Krishnaswami, S.; Turekian, Karl K.; Shaw, Henry

    1992-07-01

    The activities of members of the 238U and 232Th decay chains have been determined in water from well J-13 at the Nevada Test Site near Yucca Mountain. Using 222Rn as a measure of recoil flux, adsorption (k1) and desorption (k2) rate constants for Ra and Pb have been determined. The ratio (k1/k2), defined as the dimensionless distribution coefficient, K, is 1.3 × 104 for Ra and 2.7 × 104 for Pb and is estimated to be about 104 for Th.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1982-01-01

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

  17. Measurement of the {sup 232}Th neutron capture cross section in the region 5 keV-150 keV

    Energy Technology Data Exchange (ETDEWEB)

    Lobo, Georges; Corvi, Franco; Schillebeeckx, Peter; Brusegan, Antonio; Mutti, Paolo [EC-JRC-Institute for Reference Materials and Measurements, Geel (Belgium); Janeva, Natalia [Inst. for Nuclear Research and Nuclear Energy, Bulgarian Academy of Science, Sofia (Belgium)

    2002-08-01

    The average capture cross-section of {sup 232}Th has been measured at the 14.37 m flight path of GELINA, IRMM-Geel, in the energy range from 5 to 150 keV. The capture events were detected by two C{sub 6}D{sub 6} liquid scintillators and the neutron flux was measured with a {sup 10}B-loaded ionisation chamber. The data, corrected with the pulse-height weighting technique, have been normalised to the well-isolated and nearly saturated {sup 232}Th (n, {gamma}) resonances at 21.8 eV and 23.5 eV. Below 15 keV neutron energy, we do not observe the discrepancies, up to 40%, with the evaluated ENDF/B-VI data as reported by Wisshak et al.. Between 5 and 80 keV our results are about 10% systematically above the ENDF/B-VI data and approach the evaluated data between 80 and 100 keV. (author)

  18. Assessment of (226)Ra, (238)U, (232)Th, (137)Cs and (40)K activities from the northern coastline of Oman Sea (water and sediments).

    Science.gov (United States)

    Darabi-Golestan, F; Hezarkhani, A; Zare, M R

    2017-02-27

    Water and sediment samples were collected from northern coast of Oman Sea covering from Goatr to Hormoz canyon seaport. Water and sediment quality assessment for naturally or anthropogenic radionuclides at Oman Sea as a main strategic golf for trade and transit, is an important issue. Correspondence analysis (CA) by R-mode analysis represents that sigma(T)-temperature-conductivity-O2 parameters are well-correlated with (226)Ra, (232)Th and (40)K. Accordingly Q-mode analysis revealed an indicator samples of ST13W for different radionuclides, ST03W for O2, and simultaneously ST34W-ST21W-ST08W-ST04W for sigma(T) parameters. The CA results overlapped with factor and cluster analysis results that explained 85.8% of total variance of water samples. Descriptive analysis of sediments indicates more significant variation than water samples. The (232)Th and (226)Ra generally showing that ST13D to ST25D sediments that restricted to Pi Bashk coastline are concentrated from (137)Cs and (40)K. By comparison with reference-values from Iran and other parts of the world, they are acceptable with respect to environmental and radioisotope hazards.

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

    Science.gov (United States)

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

    2014-12-01

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

  20. Measurement of fission cross-section for the {sup 232}Th(n,f){sup 141}Ba reaction induced by neutrons around 14 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Chang-Lin; Fang, Kai-Hong [Lanzhou University, School of Nuclear Science and Technology, Lanzhou, Gansu Province (China); Lanzhou University, Engineering Research Center for Neutron Application, Ministry of Education, Lanzhou, Gansu Province (China); Liu, Shuang-Tong; Lv, Tao; Wang, Qiang; Zhang, Zheng-Wei [Lanzhou University, School of Nuclear Science and Technology, Lanzhou, Gansu Province (China); Lai, Cai-Feng [Chinese Academy of Engineering Physics, Institute of Nuclear Physics and Chemistry, Mianyang, Sichuan Province (China)

    2016-11-15

    The fission cross-section of the {sup 232}Th(n,f){sup 141}Ba reaction induced by neutrons around 14 MeV was measured precisely with the neutron activation and off-line gamma-ray spectrometric technique. Neutron fluence was monitored on-line using the accompanying α-particles from the {sup 3}H({sup 2}H,n){sup 4}He reaction, whereas the neutron energies were measured by the method of cross-section ratios of {sup 90}Zr(n,2n){sup 89}Zr to {sup 93}Nb(n,2n){sup 92m}Nb reactions. The experimentally determined {sup 232}Th(n,f){sup 141}Ba reaction cross-sections were 12.2 ± 0.4 mb at E{sub n} = 14.1 ± 0.3 MeV, 13.0 ± 0.5 mb at E{sub n} = 14.5 ± 0.3 MeV and 13.3 ± 0.5 mb at E{sub n} = 14.7 ± 0.3 MeV, respectively. (orig.)

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

    CERN Document Server

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

    2013-01-01

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

  2. K-components for the approx. 1. 4-, approx. 1. 6-, and approx. 1. 7-MeV structures in the fission of /sup 232/Th + n

    Energy Technology Data Exchange (ETDEWEB)

    Auchampaugh, G.F.; Plattard, S.; Hill, N.W.; de Saussure, G.; Perez, R.B.; Harvey, J.A.

    1981-07-01

    Neutron-induced angle-integrated fission cross sections of /sup 232/Th were measured from 0.7 to 9 MeV with a nominal neutron energy resolution of 0.15 ns/m. Data were taken for the angular intervals 0 to 23.4/sup 0/, 0 to 33.7/sup 0/, 0 to 51.7/sup 0/, and 0 to 90/sup 0/. The structures at approx. 1.4, approx. 1.6, and approx. 1.7 MeV were interpreted in terms of rotational bands with K = 1/2, 3/2, and greater than or equal to 5/2. The approximate relative fission strengths for the K-bonds are in the proportion 1.7:2.4:1.0, 0.0:2.6:1.0, and 1.0:2.8:0.0 for the three structures, respectively.

  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. Separation and quantification of {sup 238}U, {sup 232}Th and rare earths in monazite samples by ion chromatography coupled with on-line flow scintillation detector

    Energy Technology Data Exchange (ETDEWEB)

    Borai, E.H.; Mady, A.S

    2002-10-01

    An alternative procedure has been described for efficient separation and quantitative determination of uranium (U), thorium (Th) and rare earth elements (REEs) in monazite mineral by high performance ion chromatographic system (IC). Different variables affecting the distribution coefficient, the retention and hence separation efficiency such as eluent flow rate and concentrations of HCl and ammonium sulfate (NH{sub 4}){sub 2}SO{sub 4} containing the mobile phase were studied. The developed separation protocol of U, Th and REEs was optimized using an Ion Pac CS5 separation column followed by post-column derivatization reaction with Arsenaso III and UV-VIS spectrophotometeric detection. Comparative evaluation of U, Th and REEs concentration in monazite mineral was demonstrated using two different on-line detection modes including flow through cell scintillation detector (FSD) and UV-VIS spectrophotometer. Response of the FSD was found to be linear over the full range of activities investigated (4-100 Bq). The lower limits of detection (LLD) for the investigated radionuclides were 3.0{+-}0.1 Bq for {sup 238}U and 6.0{+-}0.1 Bq for {sup 232}Th. The detection of {sup 238}U and {sup 232}Th by FSD shows good agreement with the corresponding determination by UV-VIS spectrophotometer. The content of ThO{sub 2} and U{sub 3}O{sub 8} in monazite sample were found to be 4.7{+-}0.1% and 0.42{+-}0.04% using UV-VIS detector and 4.3{+-}0.1% and 0.45{+-}0.1% using FSD, respectively.

  5. 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.

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

    Indian Academy of Sciences (India)

    M A Misdaq; A Mortassim

    2009-11-01

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

  7. 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.

  8. The study of the (α, α'f) reaction at 120MeV on 232Th (III) : Total kinetic energies and mass distributions for excitation energies below 12 MeV

    NARCIS (Netherlands)

    David, P.; Debrus, J.; Janszen, H.; Schulze, J.; Harakeh, M.N.; Plicht, J. van der; van der Woude, Adriaan

    1982-01-01

    The total kinetic energy release (TKE) of the fissioning nucleus 232Th is measured as a function of excitation energy and for various mass separations. A direct correlation of the TKE and of the prompt neutron yield excitation functions is observed. The mass yield is presented as function of the tot

  9. The study of the (α, α'f) reaction at 120 MeV on 232Th and 238U (II) : Fission barrier properties deduced from fission probabilities and angular distributions

    NARCIS (Netherlands)

    Plicht, J. van der; Harakeh, M.N.; van der Woude, Adriaan; David, P.; Debrus, J.; Janszen, H.; Schulze, J.

    1981-01-01

    The fission probabilities and angular distributions of the fission fragments for the (α, α'f) reaction on 232Th and 238U at a bombarding energy of 120 MeV have been measured from about 4 to 14 MeV excitation energy. Evidence for sub-barrier resonances has been found, the negative parity ones occurri

  10. The study of the (α, α’f) reaction at 120 MeV on 232Th and 238U (I) : Fission probabilities and angular distributions in the region of the giant quadrupole resonances

    NARCIS (Netherlands)

    Plicht, J. van der; Harakeh, M.N.; van der Woude, Adriaan; David, P.; Debrus, J.; Janszen, H.; Schulze, J.

    1980-01-01

    The fission decay channel of 232Th and 238U has been investigated, using the (α, α’f) reaction at 120 MeV bombarding energy. The angular distributions of the fission fragments and the fission probabilities up to around 15 MeV excitation have been measured. No evidence for the fission decay of the gi

  11. 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

  12. The study of the (α, α’f) reaction at 120 MeV on 232Th and 238U (I) : Fission probabilities and angular distributions in the region of the giant quadrupole resonances

    NARCIS (Netherlands)

    Plicht, J. van der; Harakeh, M.N.; van der Woude, Adriaan; David, P.; Debrus, J.; Janszen, H.; Schulze, J.

    1980-01-01

    The fission decay channel of 232Th and 238U has been investigated, using the (α, α’f) reaction at 120 MeV bombarding energy. The angular distributions of the fission fragments and the fission probabilities up to around 15 MeV excitation have been measured. No evidence for the fission decay of the

  13. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-01

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

  15. 238U series isotopes and 232Th in carbonates and black shales from the Lesser Himalaya: implications to dissolved uranium abundances in Ganga-Indus source waters.

    Science.gov (United States)

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

    2003-01-01

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

  16. Near-scission emission of intermediate mass fragments in 12C+232Th at E/A=16 and 22 MeV

    Science.gov (United States)

    Bredeweg, T. A.; Yanez, R.; Davin, B. P.; Kwiatkowski, K.; de Souza, R. T.; Lemmon, R.; Popescu, R.; Charity, R. J.; Sobotka, L. G.; Hofman, D.; Carjan, N.

    2002-07-01

    Intermediate mass fragments (IMFS) (IMF: 3fission fragments following incomplete fusion in 12C+232Th at E/A=16 and 22 MeV are investigated. IMFs emitted prior to significant deformation of the fissioning system, as well as IMFs emitted near scission, are distinguished based upon their characteristic kinetic energy and angular distributions. The yield distributions of IMFs emitted near scission in these12C induced reactions are compared with near-scission IMF yields in spontaneous and low-energy ternary fission. Comparisons are made to both experimental fusion-evaporation data and theoretical predictions of a statistical model. The excitation energy dependence of relative IMF yields for both isotropic and near-scission emission is also presented. Our results for near-scission emission suggest that the production of IMFs near scission is inconsistent with a statistical emission mechanism in which emission barriers follow a standard Z dependence. Dynamical model calculations are used to investigate the role of dissipation, angular momentum, N/Z, and kinetic energy on the fragment formation near scission.

  17. Assessment of surface reactivity of thorium oxide in conditions close to chemical equilibrium by isotope exchange {sup 229}Th/{sup 232}Th method

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki-Muresan, Tomo; Perrigaud, Katy; Vandenborre, Johan; Ribet, Solange; Grambow, Bernd [Nantes Univ., CNRS/IN2P3 (France). SUBATECH Unite Mixte de Recherche 6457; Takamasa, Inai [TOKAI Univ., Kanagawa (Japan)

    2017-08-01

    This work aims to assess the solubility and the surface reactivity of crystallized thorium at pH 3.0 in presence of three types of solids: synthesized powder at 1300 C, crushed kernel, and intact kernel. In this study, the kernel is composed by the core solid from high temperature reactors (HTR) sphere particles. The originality of this work consisted in following in a sequential order the kinetic of dissolution, the surface reactivity in presence of isotope tracer {sup 229}Th, and its desorption process. Long time experiments (634 days) allowed to get deeper understanding on the behavior of the surface reactivity in contact with the solution. Solubility values are ranging from 0.3 x 10{sup -7} mol.L{sup -1} to 3 x 10{sup -7} mol.L{sup -1} with a dissolution rate of 10{sup -6}-10{sup -4} g.m{sup -2} day{sup -1}. PHREEQC modeling showed that crystallized ThO{sub 2}(cr, 20 nm) phase controls the equilibrium in solution. Isotope exchange between {sup 229}Th and {sup 232}Th indicated that well-crystallized phase exist as an inert surface regarding to the absence of exchange between surface solid and solution.

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

    Indian Academy of Sciences (India)

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

    2013-01-01

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

  19. 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).

  20. Large scale accelerator production of (225)Ac: Effective cross sections for 78-192MeV protons incident on (232)Th targets.

    Science.gov (United States)

    Griswold, J R; Medvedev, D G; Engle, J W; Copping, R; Fitzsimmons, J M; Radchenko, V; Cooley, J C; Fassbender, M E; Denton, D L; Murphy, K E; Owens, A C; Birnbaum, E R; John, K D; Nortier, F M; Stracener, D W; Heilbronn, L H; Mausner, L F; Mirzadeh, S

    2016-12-01

    Actinium-225 and (213)Bi have been used successfully in targeted alpha therapy (TAT) in preclinical and clinical research. This paper is a continuation of research activities aiming to expand the availability of (225)Ac. The high-energy proton spallation reaction on natural thorium metal targets has been utilized to produce millicurie quantities of (225)Ac. The results of sixteen irradiation experiments of thorium metal at beam energies between 78 and 192MeV are summarized in this work. Irradiations have been conducted at Brookhaven National Laboratory (BNL) and Los Alamos National Laboratory (LANL), while target dissolution and processing was carried out at Oak Ridge National Laboratory (ORNL). Excitation functions for actinium and thorium isotopes, as well as for some of the fission products, are presented. The cross sections for production of (225)Ac range from 3.6 to 16.7mb in the incident proton energy range of 78-192MeV. Based on these data, production of curie quantities of (225)Ac is possible by irradiating a 5.0gcm(-2 232)Th target for 10 days in either BNL or LANL proton irradiation facilities. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-12-30

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

  2. 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})

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

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

    CERN Document Server

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

    2016-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    张志强; 陈迪云; 宋刚; 岳玉美

    2011-01-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-07-01

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

  9. High-resolution dating of Co-rich crusts: A comparative study using the methods of orbital pacing and 230Thex/232Th dating

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Due to their slow growth rates, seamount Co-rich crusts are very difficult to date with high resolution and precision. This paper is to test the use of orbital pacing on the growth profile of crusts to determine high-resolution age and growth rate. Crust CB14 from the central Pacific Ocean was selected for this study. We first examined the growth pattern in detail under a reflected-light microscope and ascertained that the growth environment was stable for the sub-layer 1 (0-3 mm). We then used electron micro-probe line-scanning to obtain elemental profiles. The pattern of the power spectrum analysis of the Al-profile revealed that there are significant cycles of 113.9, 87.8, 51.5, 42.2 and 25.8 μm. These cycles correspond to the Milankovitch cycles of 53.1, 41, 24, 19.7 and 12 ka, respectively, and yield the growth rate of about 2.14 mm/Ma and an age of about 1.40 Ma for the boundary between the sub-layer 1 and sub-layer 2. We also used a drilling machine with a numerically controlled drive to obtain high-resolution samples at 0.1mm intervals, and used the 230Thex/232Th method to date the samples. For the uppermost 1.3 mm, the growth rate was about 2.15 mm/Ma, and the age for the layer at the depth of 3 mm was about 1.40 Ma, which coincides perfectly with the results obtained from orbital pacing. Thus, it is considered that orbital pacing is a new and effective method to determine the growth rate of the seamount Co-rich crust. This method is applicable for establishing a high-resolution age frame for the crusts of the world’s oceans.

  10. High-resolution dating of Co-rich crusts: A comparative study using the methods of orbital pacing and 230Thex/232Th dating

    Institute of Scientific and Technical Information of China (English)

    HAN XiQiu; QIU ZhongYan; MA WeiLin; QIAN JiangChu

    2009-01-01

    Due to their slow growth rates, seamount Co-rich crusts are very difficult to date with high resolution and precision. This paper is to test the use of orbital pacing on the growth profile of crusts to determine high-resolution age and growth rate. Crust CB14 from the central Pacific Ocean was selected for this study. We first examined the growth pattern in detail under a reflected-light microscope and ascertained that the growth environment was stable for the sub-layer 1 (0-3 mm). We then used electron micro-probe line-scanning to obtain elemental profiles. The pattern of the power spectrum analysis of the AI-profile revealed that there are significant cycles of 113.9, 87.8, 51.5, 42.2 and 25.8 pro. These cycles correspond to the Milankovitch cycles of 53.1, 41,24, 19.7 and 12 ka, respectively, and yield the growth rate of about 2.14 mm/Ma and an age of about 1.40 Ma for the boundary between the sub-layer 1 and sub-layer 2. We also used a drilling machine with a numerically controlled drive to obtain high-resolution samples at 0.1 mm intervals, and used the 230Thex/232Th method to date the samples. For the uppermost 1.3 mm, the growth rate was about 2.15 mm/Ma, and the age for the layer at the depth of 3 mm was about 1.40 Ma, which coincides perfectly with the results obtained from orbital pacing. Thus, it is considered that orbital pacing is a new and effective method to determine the growth rate of the seamount Co-rich crust. This method is applicable for establishing a high-resolution age frame for the crusts of the world's oceans.

  11. Allanite from the El Muerto Pegmatite, Oaxaca, Mexico: A Potential New Standard for 232Th-208Pb Dating by LA-ICP-MS

    Science.gov (United States)

    Price, J.; Crowley, J. L.; Solari, L.; Prol-Ledesma, R.

    2012-12-01

    Allanite dating may be important to studies addressing tectonomagmatic evolution, provenance of monocyclic sediment, and mineral weathering. Obtaining accurate allanite ages by SIMS has been challenging and time-consuming due to the mineral's extreme chemical variability which often prevents finding adequately matrix-matched standards. Isotopic measurements by LA-ICP-MS minimize the need for standards of nearly identical composition to the unknown allanite being analyzed, and it is done relatively rapidly. Dating by LA-ICP-MS requires high quality standards for isotopic fractionation corrections. However, readily accessible and well characterized allanite standards are scarce. We investigated gemstone allanite from the El Muerto pegmatite, Oaxaca, Mexico, as a potential new geochronology standard for 232Th-208Pb allanite dating by LA-ICP-MS. Compositional homogeneity was thoroughly investigated by scanning and backscatter electron microscopy, cathodoluminescence, quantitative and qualitative energy dispersive x-ray spectroscopy, electron microprobe, and LA-ICP-MS. The possibility of metamictization was investigated by extensive X-ray diffraction analyses. The El Muerto allanite was U-Pb dated by ID-TIMS, with common Pb ratios determined from cogenetic K-feldspar by ID-TIMS and LA-MC-ICP-MS. Future work includes Th-Pb dating by ID-TIMS. The samples investigated are homogeneous with respect to major and trace elements. Major element compositional results are generally in agreement with published values, and no metamictization was identified despite the allanite being nearly 1 Ga. The only limitation of the El Muerto allanite is that it contains small, generally <100 μm, scarce inclusions of quartz, calciothorite, albite, calcite, and biotite. However, these grains are easily recognized and avoided during LA-ICP-MS analyses. Based on these results, the El Muerto allanite has the potential to serve as a standard for LA-ICP-MS dating.

  12. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-09-01

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

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

    Science.gov (United States)

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

    2008-09-01

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

  15. 210Pb- 226Ra and 228Ra- 232Th systematics in young arc lavas: implications for magma degassing and ascent rates

    Science.gov (United States)

    Turner, Simon; Black, Stuart; Berlo, Kim

    2004-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-07-01

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

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

    Institute of Scientific and Technical Information of China (English)

    ZhangHuan-Qiao; LiuZu-Hua; 等

    1997-01-01

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

  18. 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)

  19. 235U, 238U, 232Th, 40K and 137Cs activity concentrations in marine sediments along the northern coast of Oman Sea using high-resolution gamma-ray spectrometry.

    Science.gov (United States)

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

    2012-09-01

    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.

  20. Characterization of bauxite residue (red mud) for (235)U, (238)U, (232)Th and (40)K 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.

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

    Science.gov (United States)

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

    2016-02-01

    Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland.

  2. Parameters of the best approximation of reduced neutron widths distribution. Actinides

    CERN Document Server

    Sukhovoj, A M

    2011-01-01

    The data of ENDF/B-VII library on reduced neutron widths for nuclei 231Pa, 232Th, 233,234,235,236,238U, 237Np, 239,240,241,242Pu, 241,243Am and 243Cm (including p-resonances of 232Th, 238U, 239Pu) in form of cumulative sums in function on Gamma0n/ were approximated by variable number K of partial items 0

  3. Actualizing of calibration curves of {sup 14}C/C, {sup 90}Sr/Ca, {sup 228}Th/{sup 232}Th in ivory for the determination of the post mortal interval of elephants and consequences of the radiation protection of non-human species; Aktualisierung von Kalibierkurven von {sup 14}C/C, {sup 90}Sr/Ca und {sup 228}Th/{sup 232}Th in Elefantenelfenbein zum Zwecke der Alterbestimmung und die Konsequenzen fuer den Strahlenschutz nicht-menschlicher Arten

    Energy Technology Data Exchange (ETDEWEB)

    Schupfner, R. [Regensburg Univ. (Germany). ZRN-URA Lab.

    2016-07-01

    The determination of the activity concentration of the radionuclides {sup 14}C/C and {sup 90}Sr/Ca and {sup 228}Th/{sup 232}Th applying combined radionuclide analyses methods has been proved to be a suitable tool for the purpose of an unambiguous age determination of elephant ivory [1, 2, 3, 10, 11, 12, 13]. Analysing representative and independently dated samples (N = 28) of ivory the curves fitting the post mortal interval (PMI) versus the activity concentration of the radionuclides mentioned above produced the data base enabling a more unambiguous age determination. Data from these studies origin [1, 2, 3, 10, 11, 12, 13] in analyses of ivory samples which were available up to the 2012. During the last five years there was a gap in information of the future trend of {sup 14}C/C and {sup 90}Sr/Ca. Up to this study it was not possible to assess whether the future level of {sup 14}C/C as well as {sup 90}Sr/Ca can analytically be distinguished from the level before 1954. At about 1954 the activity concentration of radionuclides from the atmospheric nuclear explosion, as {sup 14}C and {sup 90}Sr, increased in ivory significantly. This study aims in closing this information gap. The results of analyses of {sup 14}C/C, {sup 90}Sr/Ca, {sup 228}Th/{sup 232}Th in ivory with PMI values ranging from 1 to 5 years are presented and interpreted. These data enable an actualization of the calibration curves of PMI versus specific activities. This is necessary for a better understanding of the effect of blindness of {sup 14}C/C dating and its prevention. On the base of all available results form independent dated ivory sample available up to 2015 a suitable analytical procedure is suggested which aims in a more precise and reliable age determination of elephant tusks. Results of determining of radionuclides {sup 14}C/C and {sup 90}Sr/Ca and {sup 228}Th/{sup 232}Th in ivory are shown from before 1950 to 2015. These results are discussed with respect the purposes of dating as well

  4. Measurement of 232Th(n,2n)231Th reaction cross-sections at neutron energies of 14.1 MeV and 14.8 MeV using neutron activation method

    Institute of Scientific and Technical Information of China (English)

    兰长林; 解保林; 张凯; 彭猛; 方开洪

    2015-01-01

    In this study, the activation cross-sections were measured for 232Th(n,2n)231Th reactions at neutron ener-gies of 14.1 and 14.8 MeV, which were produced by a neutron generator through a T(d,n) 4He reaction. In-duced gamma-ray activities were measured using a low background gamma ray spectrometer equipped with a high resolution HPGe detector. In the cross-section calculations, corrections were made regarding the effects of gamma-ray attenuation, dead-time, fluctuation of the neutron flux, and low energy neutrons. The mea-sured cross-sections were compared with the literature data, evaluation data (ENDF-B/VII.1, JENDL-4.0 and CENDL-3.1), and the results of the model calculation (TALYS1.6).

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

    Energy Technology Data Exchange (ETDEWEB)

    Aerts, G

    2005-09-01

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

  6. Post-Irradiation Examination of 237Np Targets for 238Pu Production

    Energy Technology Data Exchange (ETDEWEB)

    Morris, Robert Noel [ORNL; Baldwin, Charles A [ORNL; Hobbs, Randy W [ORNL; Schmidlin, Joshua E [ORNL

    2015-01-01

    Oak Ridge National Laboratory is recovering the US 238Pu production capability and the first step in the process has been to evaluate the performance of a 237Np target cermet pellet encased in an aluminum clad. The process proceeded in 3 steps; the first step was to irradiate capsules of single pellets composed of NpO2 and aluminum power to examine their shrinkage and gas release. These pellets were formed by compressing sintered NpO2 and aluminum powder in a die at high pressure followed by sintering in a vacuum furnace. Three temperatures were chosen for sintering the solution precipitated NpO2 power used for pellet fabrication. The second step was to irradiate partial targets composed of 8 pellets in a semi-prototypical arrangement at the two best performing sintering temperatures to determine which temperature gave a pellet that performed the best under the actual planned irradiation conditions. The third step was to irradiate ~50 pellets in an actual target configuration at design irradiation conditions to assess pellet shrinkage and gas release, target heat transfer, and dimensional stability. The higher sintering temperature appeared to offer the best performance after one cycle of irradiation by having the least shrinkage, thus keeping the heat transfer gap between the pellets and clad small minimizing the pellet operating temperature. The final result of the testing was a target that can meet the initial production goals, satisfy the reactor safety requirements, and can be fabricated in production quantities. The current focus of the program is to verify that the target can be remotely dissembled, the pellets dissolved, and the 238Pu recovered. Tests are being conducted to examine these concerns and to compare results to code predictions. Once the performance of the full length targets has been quantified, the pellet 237Np loading will be revisited to determine if it can be increased to increase 238Pu production.

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

    Institute of Scientific and Technical Information of China (English)

    羊奕伟; 刘荣; 蒋励; 鹿心鑫; 王玫; 严小松

    2014-01-01

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

  8. Evaluation of (n,n') scatteriung cross sections from 0. 8 to 2. 5 MeV for higher collective bands of /sup 232/Th and /sup 238/U in ''standard'' (CN + DI) and ''unified'' (Weidenmerller s-matrix) formalisms

    Energy Technology Data Exchange (ETDEWEB)

    Sheldon, E.; Chan, D.W.S.

    1982-01-01

    Angle-integrated cross sections for inelastic scattering of fast neutrons from 0.8 to 2.5 MeV on /sup 232/Th and /sup 238/U, proceeding to higher collective (quadrupole and octupole vibrational) states in the residual nuclei, have been computed in a standard and a unified approach; the resulting excitation functions have been compared with the experimental data of the Lowell group. In all calculations, a consistent set of optical potential and deformation parameters, as derived by Haouat and Lagrange of the Bruyeres group, was used. The standard formalism employed an incoherent sum of compound-nucleus (CN) and coupled-channels direct-interaction (DI) cross section, evaluated with the programs CINDY and KARJUP (Karlsruhe version of JUPITOR) respectively. Provision was made for the effect of level-width fluctuations and for competing neutron exit channels. The results in general compared well with the measured values, but in several instances disagreed significantly with the ENDF/B-V evaluated data. Still better agreement ensued from the use of the unified formalism based upon energy-averaged second moments of transformed S-matrix elements in a statistical approach developed by Weidenmueller at al. and embodied within a new fluctuation program NANCY with coupled channels and competing channels to generate and manipulate the grand ensemble of S-matrix elements. With only the coupling strengths as adjustable parameters, this offers a promising, reliable means of analysis well suited to the interpretation of neutron scattering on deformed actinide nuclei.

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

    Institute of Scientific and Technical Information of China (English)

    朱明燕; 郭冬发; 崔建勇; 刘宇昂; 谭靖; 张彦辉

    2009-01-01

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

  10. 232Th、233U、238Pu、240Pu、242Pu、241Am、242Cm、243Cm和244Cm的裂变释放热能研究%Thermal Energy Released in Fission of 232 Th,233 U,238 Pu, 240 Pu,242 Pu,241 Am,242 Cm,243 Cm and 244 Cm

    Institute of Scientific and Technical Information of China (English)

    赵艳飞; 马续波; 陈义学

    2013-01-01

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

  11. Measurements of periods, relative abundances and absolute yields of delayed neutrons from fast neutron induced fission of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Piksaikine, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    The experimental method for measurements of the delayed neutron yields and period is presented. The preliminary results of the total yield, relative abundances and periods are shown comparing with the previously reported values. (J.P.N.)

  12. Measurements of periods, relative abundances and absolute yields of delayed neutrons from fast neutron induced fission of {sup 237}Np

    Energy Technology Data Exchange (ETDEWEB)

    Piksaikine, V. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    The experimental method for measurements of the delayed neutron yields and period is presented. The preliminary results of the total yield, relative abundances and periods are shown comparing with the previously reported values. (J.P.N.)

  13. 242Pu as tracer for simultaneous determination of 237Np and 239,240Pu in environmental samples

    DEFF Research Database (Denmark)

    Chen, Q.J.; Dahlgaard, H.; Nielsen, S.P.;

    2002-01-01

    A procedure has been developed using Pu-242 as tracer for simultaneous determination of Np-237 and Pu-239,Pu-240 in environmental samples. The validity of the method has been demonstrated by ICPMS and alpha-spectroscopy for up to 10 gram soil and sediment, seawater up to 200 litres. The paper...... describes a suitable chemical procedure for Np and Pu including a quantitative pre-concentration of neptunium and plutonium, preparation of Np4+ and Pu4+, NP(NO3)(6)(2-) and Pu(NO3)(6)(2-), The ratio of Np-237/Pu-242 (or Np-237/Pu-239) before and after the procedure has been determined using 10 g soil (free...... from Np and Pu) R-before/R-after = 1.004 +/- 3.3% (S.D n = 20) and 1 litre seawater R-before/R-after = 1.019+/-1.9% (S.D., n = 12). Results from the intercomparison samples LAEA-135, LAEA-381 and from environmental samples are presented....

  14. Procedures for determination of 239,240Pu, 241Am, 237Np, 234,238U, 2

    DEFF Research Database (Denmark)

    Chen, Q.J.; Aarkrog, Asker; Nielsen, Sven Poul;

    2001-01-01

    Since 1987, the Department of Nuclear Safety Research, Risø National Laboratory has developed procedures for analysis of low-level amounts of radioactivity in large samples of 200 liters seawater, 10 gram sediment, soil and other environmental materials.These analytical procedures provide high ch...

  15. Rapid determination of (237)Np and plutonium isotopes in urine by inductively-coupled plasma mass spectrometry and alpha spectrometry.

    Science.gov (United States)

    Maxwell, Sherrod L; Culligan, Brian K; Jones, Vernon D; Nichols, Sheldon T; Noyes, Gary W; Bernard, Maureen A

    2011-08-01

    A new rapid separation method was developed for the measurement of plutonium and neptunium in urine samples by inductively-coupled plasma mass spectrometry (ICP-MS) and/or alpha spectrometry with enhanced uranium removal. This method allows separation and preconcentration of plutonium and neptunium in urine samples using stacked extraction chromatography cartridges and vacuum box flow rates to facilitate rapid separations. There is an increasing need to develop faster analytical methods for emergency response samples. There is also enormous benefit to having rapid bioassay methods in the event that a nuclear worker has an uptake (puncture wound, etc.) to assess the magnitude of the uptake and guide efforts to mitigate dose (e.g., tissue excision and chelation therapy). This new method focuses only on the rapid separation of plutonium and neptunium with enhanced removal of uranium. For ICP-MS, purified solutions must have low salt content and low concentration of uranium due to spectral interference of (238)U(1)H(+) on m/z 239. Uranium removal using this method is enhanced by loading plutonium and neptunium initially onto TEVA resin, then moving plutonium to DGA resin where additional purification from uranium is performed with a decontamination factor of almost 1×10(5). If UTEVA resin is added to the separation scheme, a decontamination factor of ~3 × 10(6) can be achieved.

  16. Angular distributions in the neutron-induced fission of actinides

    CERN Multimedia

    In 2003 the n_TOF Collaboration performed the fission cross section measurement of several actinides ($^{232}$Th, $^{233}$U, $^{234}$U, $^{237}$Np) at the n_TOF facility using an experImental setup made of Parallel Plate Avalanche Counters (PPAC). The method based on the detection of the 2 fragments in coincidence allowed to clearly disentangle the fission reactions among other types of reactions occurring in the spallation domain. We have been therefore able to cover the very broad neutron energy range 1eV-1GeV, taking full benefit of the unique characteristics of the n_TOF facility. Figure 1 shows an example obtained in the case of $^{237}$Np where the n_ TOF measurement showed that the cross section was underestimated by a large factor in the resonance region.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-03-01

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

  18. Fissility of actinide nuclei induced by 60-130 MeV photons; Fissionabilidade de nucleos actnideos induzida por fotons de energia 60-130 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Morcelle, Viviane; Tavares, Odilon A.P

    2004-06-15

    Nuclear fissilities obtained from recent photofission reaction cross section measurements carried out at Saskatchewan Accelerator Laboratory (Saskatoon, Canada) in the energy range 60-130 MeV for {sup 232} Th, {sup 233} U, {sup 235} U, {sup 238} U, and {sup 237} Np nuclei have been analysed in a systematic way. To this aim, a semiempirical approach has been developed based on the quasi-deuteron nuclear photoabsorption model followed by the process of competition between neutron evaporation and fission for the excited nucleus. The study reproduces satisfactorily well the increasing trend of nuclear fissility with parameter Z{sup 2}=A. (author)

  19. Burnup analysis of the VVER-1000 reactor using thorium-based fuel

    Energy Technology Data Exchange (ETDEWEB)

    Korkmaz, Mehmet E.; Agar, Osman; Bueyueker, Eylem [Karamanoglu Mehmetbey Univ., Karaman (Turkey). Faculty of Kamil Ozdag Science

    2014-12-15

    This paper aims to investigate {sup 232}Th/{sup 233}U fuel cycles in a VVER-1000 reactor through calculation by computer. The 3D core geometry of VVER-1000 system was designed using the Serpent Monte Carlo 1.1.19 Code. The Serpent Code using parallel programming interface (Message Passing Interface-MPI), was run on a workstation with 12-core and 48 GB RAM. {sup 232}Th/{sup 235}U/{sup 238}U oxide mixture was considered as fuel in the core, when the mass fraction of {sup 232}Th was increased as 0.05-0.1-0.2-0.3-0.4 respectively, the mass fraction of {sup 238}U equally was decreased. In the system, the calculations were made for 3 000 MW thermal power. For the burnup analyses, the core is assumed to deplete from initial fresh core up to a burnup of 16 MWd/kgU without refuelling considerations. In the burnup calculations, a burnup interval of 360 effective full power days (EFPDs) was defined. According to burnup, the mass changes of the {sup 232}Th, {sup 233}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 241}Am and {sup 244}Cm were evaluated, and also flux and criticality of the system were calculated in dependence of the burnup rate.

  20. Reanalysis of the Gas-cooled fast reactor experiments at the zero power facility Proteus – Spectral indices

    Directory of Open Access Journals (Sweden)

    Girardin G.

    2013-03-01

    Full Text Available PROTEUS is a zero power reactor at the Paul Scherrer Institute which has been employed during the 1970’s to study experimentally the physics of the gas-cooled fast reactor. Reaction rate distributions, flux spectrum and reactivity effects have been measured in several configurations featuring PuO2/UO2 fuel, absorbers, large iron shields, and thorium oxide and thorium metal fuel either distributed quasihomogeneously in the reference PuO2/UO2 lattice or introduced in the form of radial and axial blanket zones. This papers focus on the spectral indices – including fission and capture in 232Th and 237Np - measured in the reference PuO2/UO2 lattices and their predictions with an MCNPX model specially developed for the PROTEUS-GCFR core. Predictions were obtained with JEFF-3.1 and -3.11, ENDF/B-VII.0 and VII.1, and JENDL-3.3 and -4.0. A general good agreement was demonstrated. The ratio of 232Th fission to 239Pu fission, however, was under-predicted by 8.7±2.1% and 6.5±2.1% using ENDF/B-VII.0 and VII.1, respectively. Finally, the capture rates in 237Np tended to be underpredicted by the JEFF and JENDL libraries, although the new cross section in JEFF-3.1.1 slightly improved the 237Np capture to 239Pu fission results (3.4±2.4%.

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

    CERN Document Server

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

    2014-01-01

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

  2. Critical dimensions of /sup 235/U aqueous systems containing /sup 238/U or /sup 232/Th (LWBR Development Program)

    Energy Technology Data Exchange (ETDEWEB)

    Jones, L.L. Jr.; Romesburg, H.C.

    1966-09-01

    Criticality data for homogeneous water moderated and reflected systems containing U/sup e/O/sub 2/ and thoria were analyzed to provide data that will be used to establish fuel handling and storage criteria for finely divided mixtures and alloys of U/sup e/O/sub 2/ + ThO/sub 2/. Homogeneous, water reflected and moderated spheres of thoria containing a wide range of U/sup e/O/sub 2/ wt % have been analyzed by four-group diffusion theory utilizing the one-dimensional code WANDA. The fast-group constants were obtained from the MUFT 5 code which weights a 54-group microscopic cross-section set over a spectrum determined by the buckling and material composition and coalesces these into three fast-group constants. The thermal-group constants were obtained with the KATE 1 code using the ''mixed number density'' option. Stearic acid and sugar were compared with water for effectiveness of moderation and reflection. Water proved to be the best moderator thus far, but sugar (at theoretical density) proved to be superior to water as a reflector. (NSA 21: 1543)

  3. 238U, 232Th profiling and U-series isotope analysis of fossil teeth by laser ablation-ICPMS

    Science.gov (United States)

    Eggins, Stephen; Grün, Rainer; Pike, Alistair W. G.; Shelley, Michael; Taylor, Lois

    2003-05-01

    U and Th concentration profiles in fossil hominid and faunal teeth have been measured by laser ablation ICPMS. These profiles record diverse modes of U and Th uptake, particularly within enamel, that can be broadly related to the state of sample preservation. Observed U profiles are in general inconsistent with existing diffusion-adsorption models developed for U-uptake in bone and teeth. Where the models appear applicable, calculated diffusion rates are several orders of magnitude smaller than previous estimates. Laser ablation ICPMS offers a means of rapidly characterizing U and Th distributions in the enamel and dentine components of teeth as a precursor to ESR and U-series dating. In particular, it should allow the identification of teeth (and also bone) samples that have simple U-uptake histories and are amenable to precise dating by time-consuming and expensive Th-U and Pa-U TIMS techniques. We also demonstrated the use of laser ablation ICPMS to measure U-series isotopes in dentine and enamel samples with relatively high U concentrations (>20 ppm). These results, obtained using a quadrupole ICPMS, illustrate significant promise for in situ U-series isotope analysis, particularly when combined with the greater sensitivity and multi-collection capabilities of new sector ICPMS instrumentation. The latter may permit precise isotope ratio measurements on samples containing only a few ppm of U.

  4. Fission Product Yields from 232Th, 238U, and 235U Using 14 MeV Neutrons

    Science.gov (United States)

    Pierson, B. D.; Greenwood, L. R.; Flaska, M.; Pozzi, S. A.

    2017-01-01

    Neutron-induced fission yield studies using deuterium-tritium fusion-produced 14 MeV neutrons have not yet directly measured fission yields from fission products with half-lives on the order of seconds (far from the line of nuclear stability). Fundamental data of this nature are important for improving and validating the current models of the nuclear fission process. Cyclic neutron activation analysis (CNAA) was performed on three actinide targets-thorium-oxide, depleted uranium metal, and highly enriched uranium metal-at the University of Michigan's Neutron Science Laboratory (UM-NSL) using a pneumatic system and Thermo-Scientific D711 accelerator-based fusion neutron generator. This was done to measure the fission yields of short-lived fission products and to examine the differences between the delayed fission product signatures of the three actinides. The measured data were compared against previously published results for 89Kr, -90, and -92 and 138Xe, -139, and -140. The average percent deviation of the measured values from the Evaluated Nuclear Data Files VII.1 (ENDF/B-VII.1) for thorium, depleted-uranium, and highly-enriched uranium were -10.2%, 4.5%, and -12.9%, respectively. In addition to the measurements of the six known fission products, 23 new fission yield measurements from 84As to 146La are presented.

  5. ORELA contribution to thorium-cycle nuclear data

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D.K.

    1982-01-01

    The measurements of direct importance to the /sup 232/Th//sup 233/U fuel cycle using neutrons from the Oak Ridge Linear Accelerator Facility are gathered together and discussed. These measurements were done in response to specific data discrepancies, as part of generic programs, and for basic fission physics studies. In particular, completed transmission and capture work on /sup 232/Th has yielded the most accurate parameters for the first four s-wave resonances; the largest average capture width, 25.2 MeV; and the largest s-wave strength function of recent measurements. These results allow improved agreement between differential and integral capture rates. Moreover, the ORNL /sup 252/Cf anti nu measurement of unprecedented accuracy and /sup 233/U anti nu ratio measurement give a /sup 233/U prompt anti nu (thermal) of 2.490 +- 0.009 neutron/fission. This result allows a much more satisfactory understanding of the /sup 233/U 2200 m/s constants. In addition, a /sup 232/Th ..gamma..-ray production measurement provides needed cross sections for shielding, and important data for both application and fission physics were obtained from /sup 232/Th fission and both /sup 231/Pa and /sup 234/U fission and total cross section measurements. Data requirements and discrepancies suggested from this work are discussed.

  6. Level Densities in the actinide region and indirect n,y cross section measurements using the surrogate method

    Directory of Open Access Journals (Sweden)

    Wiedeking M.

    2012-02-01

    Full Text Available Results from a program of measurements of level densities and gamma ray strength functions in the actinide region are presented. Experiments at the Oslo cyclotron involving the Cactus/Siri detectors and 232Th(d,x and 232Th(3He,x reactions were carried out to help answer the question of which level density model is the most appropriate for actinide nuclei, since it will have an impact on cross section calculations important for reactor physics simulations. A new technique for extracting level densities and gamma ray strength functions from particle-gamma coincidence data is proposed and results from the development of this technique are presented. In addition, simultaneous measurements of compound nuclear gamma decay probabilities have been performed for the key thorium cycle nuclei 233Th, 231Th and 232Pa up to around 1MeV above the neutron binding energy and have enabled extraction of indirect neutron induced capture cross sections for the 232Th, 231Pa and 230Th nuclei using the surrogate reaction method. Since the neutron capture cross section for 232Th is already well known from direct measurements a comparison provides a stringent test of the applicability of the surrogate technique in the actinide region.

  7. Energetic identification of ions of very low fluence; Identificacion energetica de iones de muy baja fluencia

    Energy Technology Data Exchange (ETDEWEB)

    Mut C, D.A.; Balcazar, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2005-07-01

    The calibration of 2 types of plastics is presented (cellulose nitrate and polycarbonate) that detect and identify the energy of helium slight ions (1.5 to 10 MeV) and protons (0.3 to 6 MeV) in flows so low of a single particle /cm{sup 2}. This methodology is of importance in radiological protection to identify the actinides {sup 232} Th, {sup 241} Am, {sup 238} U, {sup 235} U, {sup 237} Np by means of its alpha emissions, or to carry out neutron spectroscopy in an ignored energy field by protons retrocession. The ion identification is adjusted for all the cases to a simple expression of the exponential type. The comparison is achieved among detection efficiencies for the detectors. (Author)

  8. Measurements of thermal fission and capture cross sections of minor actinides within the Mini-INCA project

    Energy Technology Data Exchange (ETDEWEB)

    Bringer, O.; Chabod, S.; Dupont, E.; Letourneau, A.; Panebianco, S.; Veyssiere, Ch. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Oriol, L. [CEA Cadarache, Dept. d' Etudes des Reacteurs, 13 - Saint Paul lez Durance (France); Chartier, F. [CEA Saclay, Dept. de Physico-Chimie, 91 - Gif sur Yvette (France); Mutti, P. [Institut Laue Langevin, 38 - Grenoble, (France); AlMahamid, I. [Wadsworth Center, New York State Dept. of Health, Albany, NY (United States)

    2008-07-01

    In the framework of nuclear waste transmutation studies, the Mini-INCA project has been initiated at Cea/DSM to determine optimal conditions for transmutation and incineration of Minor Actinides in high intensity neutron fluxes in the thermal region. Our experimental tool is based on alpha- and gamma-spectroscopy of irradiated samples and microscopic fission-chambers. It can provide both microscopic information on nuclear reactions (total and partial cross sections for neutron capture and/or fission reactions) and macroscopic information on transmutation and incineration potentials. The {sup 232}Th, {sup 237}Np, {sup 241}Am, and {sup 244}Cm transmutation chains have been explored in details, showing some discrepancies in comparison with evaluated data libraries but in overall good agreement with recent experimental data. (authors)

  9. Photon and proton induced fission on heavy nuclei at intermediate energies

    Directory of Open Access Journals (Sweden)

    Andrade-II E.

    2014-04-01

    Full Text Available We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on 241Am, 238U, and 237Np targets and the Bremmstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on 232Th and 238U targets. The study was performed by means of the Monte Carlo simulation code CRISP. A multimodal fission extension was added to the code within an approach which accounts for the contribution of symmetric and asymmetric fission. This procedure allowed the investigation of fission cross sections, fissility, number of evaporated nucleons and fission-fragment charge distributions. The comparison with experimental data show a good agreement between calculations and experiments.

  10. Moessbauer spectroscopy in neptunium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Nakamoto, Tadahiro; Nakada, Masami; Masaki, Nobuyuki; Saeki, Masakatsu [Japan Atomic Energy Research Inst., Tokyo (Japan)

    1997-03-01

    Moessbauer effects are observable in seven elements of actinides from {sup 232}Th to {sup 247}Cm and Moesbauer spectra have been investigated mainly with {sup 237}Np and {sup 238}U for the reasons of availability and cost of materials. This report describes the fundamental characteristics of Moessbauer spectra of {sup 237}Np and the correlation between the isomer shift and the coordination number of Np(V) compounds. The isomer shifts of Np(V) compounds had a tendency to increase as an increase of coordination number and the isomer shifts of Np(V) compounds showed broad distribution as well as those of Np(VI) but {delta} values of the compounds with the same coordination number were distributed in a narrow range. The {delta} values of Np(VI) complexes with O{sub x} donor set suggest that the Np atom in its hydroxide (NpO{sub 2}(OH){center_dot}4H{sub 2}O)might have pentagonal bipyramidal structure and at least, pentagonal and hexagonal bipyramidal structures might coexist in its acetate and benzoate. Really, such coexistence has been demonstrated in its nitrate, (NpO{sub 2}){sub 2}(NO{sub 3}){sub 2}{center_dot}5H{sub 2}O. (M.N.)

  11. Investigation of Space and Energy Distributions of Neutrons Generated in Lead Target and Uranium Blanket of the Electronuclear System "Energy plus Transmutation" under Irradiation with Protons at 1.5 GeV

    CERN Document Server

    Zhuk, I V; Krivopustov, M I; Sosnin, A N; Chultem, D; Vestmaer, V; Tumendelger, T; Zaveryukha, O S; Pavlyuk, A B

    2002-01-01

    The work contains the results of space-energy distributions of neutrons in U/Pb assembly, consisting of extended lead target and the model of natural uranium blanket irradiated with relativistic protons at 1.5 GeV. The research is carried out in the framework of a series of experiments using the model of subcritical heterogeneous electronuclear system at the Laboratory of High Energies, JINR, Dubna ("Investigation of Physical Aspects of Electronuclear Method of Energy Production and Transmutation of Radioactive Waste Using Beams from JINR Synchrophasotron/Nuclotron" - project "Energy plus Transmutation"). The results of measurements and calculations of ^{235}U, ^{238}U and ^{232}Th fission rate distributions as well as threshold spectral indexes {\\bar\\sigma_f^{^{232}Th}}/{\\bar\\sigma_f^{^{235}U}} and {\\bar\\sigma_f^{^{238}U}}/{\\bar\\sigma_f^{^{235}U}} along the radius of the target and model uranium blanket are presented. The results of measurements and calculations of ^{234}U, ^{236}U and ^{237}Np fission rate ...

  12. Evaluation of 226Ra, 232Th, 137Cs and 40K “Agaricus Bisporus” Activity in Cultivated Edible Mushroom formed in Tehran Province- Iran

    Directory of Open Access Journals (Sweden)

    Vahid Changizi

    2013-03-01

    Full Text Available Introduction Natural and man made radioactive sources exist in our environment they can enter into our food chains. One of these is the soil-mushroom-human chain. High level doses of natural radiation can cause hazards to humans. Materials and Methods Samples of Agaricus bisporus cultivated edible mushroom in Tehran province- Iran were collected from 7 farms. Specific activity of 226Ra, 228Ra, 137Cs, 40K and 235U of the samples were measured by two HPGe detectors. Results Specific activity of 226Ra, 228Ra, 137Cs and 40K in the edible mushroom samples were equal to 0.06 ± 0.03 - 0.7 ± 0.2 Bq kg-1 dry, 1.4 ± 0.7 Bq kg-1 dry, 0.1 ± 0.03- 0.3 ± 0.1 Bq kg-1dry and 920 ± 400 - 1370 ± 900 Bq kg-1dry , respectively. Conclusion As the measured concentrations of the radionuclides of interest are close or lower than MDA (Minimum Detectable Activity. Consumption of the mushrooms would impose no health consequences to the consumers.

  13. Comparative study of different analytical methods for the determination of 238U, 234U, 235U, 230Th and 232Th in NORM samples (Southern Catalonia).

    Science.gov (United States)

    Mola, M; Palomo, M; Peñalver, A; Borrull, F; Aguilar, C

    2013-01-01

    Uranium and thorium isotopes from sludge samples taken from an area of influence of a dicalcium phosphate factory, located close to the Ebro River reservoir in Flix, and from mineral raw materials (coal and phosphate) which were deposited in Tarragona Harbour (Catalonia) have been measured. To do that, several procedures to determine these isotopes have been applied and compared in terms of accuracy, precision and total analysis time. In particular, digestion procedures, such as one based on conventional acidic digestion or another based on the use of microwave digestion, have been tested. Moreover, different radiochemical separation procedures have been applied. In this regard, one method based on liquid-liquid extraction using TBP/Xylene and another based on the use of extraction chromatography using UTEVA resins have been compared. Firstly, the different proposed methods were tested by analyzing a phosphogypsum sediment and a moss-soil sample from two different intercomparison exercises. The microwave digestion - UTEVA method provided the best results (recoveries higher than 82% for uranium and thorium isotopes) and was then applied to the NORM samples. The obtained results showed that the higher uranium and thorium activities values were found in phosphate raw material and in the more superficial samples located in sludge sediments next to the dicalcium phosphate factory. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Measurement of the $^{232}$Th (n, $\\gamma$ )/$^{58}$Ni (n, p) reaction rate ratio in the leakage neutron field of CFBR-II fast burst reactor

    CERN Document Server

    Qiang, Wang; Zihui, Ai; Chun, Zheng; Jian, Gong

    2016-01-01

    A ThO$_{2}$ sample with a nickel activation foil attached was irradiated in the leakage neutron field of CFBR-II reactor. The activities of the active products were measured after irradiation to obtain the reaction rates. The normalized reaction rates were also calculated based on the ENDF/B-VII.1, CENDL-3.1, JENDL-4.0, BROND-2.2 databases. The experimental reaction rate ratio is 4.37 with an uncertainty of 3.9\\% which is coincident with the ratios calculated based on the ENDFB-VII. 1, JENDL-4.0, BROND-2.2 databases, but is 11.2\\% larger than that based on CENDL-3.1 database.

  15. 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)

  16. 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)

  17. A comparative radiological assessment of five European biosphere systems in the context of potential contamination of well water from the hypothetical disposal of radioactive waste.

    Science.gov (United States)

    Olyslaegers, G; Zeevaert, T; Pinedo, P; Simon, I; Pröhl, G; Kowe, R; Chen, Q; Mobbs, S; Bergström, U; Hallberg, B; Katona, T; Eged, K; Kanyar, B

    2005-12-01

    In the framework of the BioMoSA project for the development of biosphere assessment models for radioactive waste disposal the Reference Biosphere Methodology developed in the IAEA programme BIOMASS was applied to five locations, situated in different European countries. Specific biosphere models were applied to assess the hypothetical contamination of a range of agricultural and environmental pathways and the dose to individuals, following contamination of well water. The results of these site-specific models developed by the different BioMoSA partners, and the individual normalised dose to the exposure groups were compared against each other. Ingestion of drinking water, fruit and vegetables were found to be among the most important pathways for almost all radionuclides. Stochastic calculations revealed that consumption habits, transfer factors, irrigation rates and distribution coefficients (Kd(s)) were the most important parameters that influence the end results. Variations in the confidence intervals were found to be higher for sorbing elements (e.g. (36)Cl, (237)Np, (99)Tc, (238)U, (129)I) than for mobile elements (e.g. (226)Ra, (79)Se, (135)Cs, (231)Pa, (239)Pu). The influence of daughter products, for which the distribution into the biosphere was calculated individually, was also shown to be important. This paper gives a brief overview of the deterministic and stochastic modelling results and the parameter sensitivity. A screening methodology was introduced to identify the most important pathways, simplify a generic biosphere tool and refine the existing models.

  18. Study of calculated and measured time dependent delayed neutron yields. [TX, for calculating delayed neutron yields; MATINV, for matrix inversion; in FORTRAN for LSI-II minicomputer

    Energy Technology Data Exchange (ETDEWEB)

    Waldo, R.W.

    1980-05-01

    Time-dependent delayed neutron emission is of interest in reactor design, reactor dynamics, and nuclear physics studies. The delayed neutrons from neutron-induced fission of /sup 232/U, /sup 237/Np, /sup 238/Pu, /sup 241/Am, /sup 242m/Am, /sup 245/Cm, and /sup 249/Cf were studied for the first time. The delayed neutron emission from /sup 232/Th, /sup 233/U, /sup 235/U, /sup 238/U, /sup 239/Pu, /sup 241/Pu, and /sup 242/Pu were measured as well. The data were used to develop an empirical expression for the total delayed neutron yield. The expression gives accurate results for a large variety of nuclides from /sup 232/Th to /sup 252/Cf. The data measuring the decay of delayed neutrons with time were used to derive another empirical expression predicting the delayed neutron emission with time. It was found that nuclides with similar mass-to-charge ratios have similar decay patterns. Thus the relative decay pattern of one nuclide can be established by any measured nuclide with a similar mass-to-charge ratio. A simple fission product yield model was developed and applied to delayed neutron precursors. It accurately predicts observed yield and decay characteristics. In conclusion, it is possible to not only estimate the total delayed neutron yield for a given nuclide but the time-dependent nature of the delayed neutrons as well. Reactors utilizing recycled fuel or burning actinides are likely to have inventories of fissioning nuclides that have not been studied until now. The delayed neutrons from these nuclides can now be incorporated so that their influence on the stability and control of reactors can be delineated. 8 figures, 39 tables.

  19. Update of the α - n Yields for Reactor Fuel Materials for the Interest of Nuclear Safeguards

    Science.gov (United States)

    Simakov, S. P.; van den Berg, Q. Y.

    2017-01-01

    The neutron yields caused by spontaneous α-decay of actinides and subsequent (α,xn) reactions were re-evaluated for the reactor fuel materials UO2, UF6, PuO2 and PuF4. For this purpose, the most recent reference data for decay parameters, α-particle stopping powers and (α,xn) cross sections were collected, analysed and used in calculations. The input data and elaborated code were validated against available thick target neutron yields in pure and compound materials measured at accelerators or with radioactive sources. This paper provides the specific neutron yields and their uncertainties resultant from α-decay of actinides 241Am, 249Bk, 252Cf, 242,244Cm, 237Np, 238-242Pu, 232Th and 232-236,238U in oxide and fluoride compounds. The obtained results are an update of previous reference tables issued by the Los Alamos National Laboratory in 1991 which were used for the safeguarding of radioactive materials by passive non-destructive techniques. The comparison of the updated values with previous ones shows an agreement within one estimated uncertainty (≈ 10%) for oxides, and deviations of up to 50% for fluorides.

  20. Rapid determination of actinides and {sup 90}Sr in river water

    Energy Technology Data Exchange (ETDEWEB)

    Habibi, A., E-mail: azza.habibi@irsn.fr [IRSN/PRP-ENV/STEME/LMRE, Rue du belvédère, Bâtiment 501, Bois des rames, 91400 Orsay (France); Boulet, B. [IRSN/PRP-ENV/STEME/LMRE, Rue du belvédère, Bâtiment 501, Bois des rames, 91400 Orsay (France); Gleizes, M. [IRSN/PRP-ENV/STEME, 31 rue de l' écluse, 78116 Le Vésinet (France); Larivière, D. [Laboratoire de radioécologie, Département de chimie, Université Laval, 1045 Avenue de la médecine, G1V 0A6 Québec (Canada); Cote, G. [PSL Research University, Chimie ParisTech CNRS, Institut de Recherche de Chimie Paris, 11 rue Pierre et Marie Curie, 75005 Paris (France)

    2015-07-09

    Highlights: • A new method to separate six actinides and {sup 90}Sr was developed. • The method was applied successfully to river water samples. • The separation and the measure take about seven hours. • The method permits to reach high yields. - Abstract: Nuclear accidents occurred in latest years highlighted the difficulty to achieve, in a short time, the quantification of alpha and beta emitters. Indeed, most of the existing methods, though displaying excellent performances, can be very long, taking up to several weeks for some radioisotopes, such as {sup 90}Sr. This study focuses on alpha and beta radioisotopes which could be accidentally released from nuclear installations and which could be measured by inductively coupled plasma mass spectrometer (ICP-MS). Indeed, a new and rapid separation method was developed for {sup 234,235,236,238}U, {sup 230,232}Th, {sup 239,240}Pu, {sup 237}Np, {sup 241}Am and {sup 90}Sr. The main objective was to minimize the duration of the separation protocol by the development of a unique radiochemical procedure with elution media compatible with ICP-MS measurements. Excellent performances were obtained with spiked river water samples. These performances are characterized by total yields exceeding 80% for all monitored radionuclides, as well as good reproducibility (RSD ≤ 10%, n = 12). The proposed radiochemical separation (including counting time) required less than 7 h for a batch of 8 samples.

  1. Review and Assessment of Neutron Cross Section and Nubar Covariances for Advanced Reactor Systems

    Energy Technology Data Exchange (ETDEWEB)

    Maslov,V.M.; Oblozinsky, P.; Herman, M.

    2008-12-01

    In January 2007, the National Nuclear Data Center (NNDC) produced a set of preliminary neutron covariance data for the international project 'Nuclear Data Needs for Advanced Reactor Systems'. The project was sponsored by the OECD Nuclear Energy Agency (NEA), Paris, under the Subgroup 26 of the International Working Party on Evaluation Cooperation (WPEC). These preliminary covariances are described in two recent BNL reports. The NNDC used a simplified version of the method developed by BNL and LANL that combines the recent Atlas of Neutron Resonances, the nuclear reaction model code EMPIRE and the Bayesian code KALMAN with the experimental data used as guidance. There are numerous issues involved in these estimates of covariances and it was decided to perform an independent review and assessment of these results so that better covariances can be produced for the revised version in future. Reviewed and assessed are uncertainties for fission, capture, elastic scattering, inelastic scattering and (n,2n) cross sections as well as prompt nubars for 15 minor actinides ({sup 233,234,236}U, {sup 237}Np, {sup 238,240,241,242}Pu, {sup 241,242m,243}Am and {sup 242,243,244,245}Cm) and 4 major actinides ({sup 232}Th, {sup 235,238}U and {sup 239}Pu). We examined available evaluations, performed comparison with experimental data, taken into account uncertainties in model parameterization and made use state-of-the-art nuclear reaction theory to produce the uncertainty assessment.

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

    Energy Technology Data Exchange (ETDEWEB)

    Pham, M.K. [International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), MC 98000 (Monaco)]. E-mail: m.pham@iaea.org; Sanchez-Cabeza, J.A.; Povinec, P.P.; Gastaud, J.; La Rosa, J.; Lee, S.-H.; Liong Wee Kwong, L.; Oregioni, B.; Wyse, E. [International Atomic Energy Agency (IAEA), Marine Environment Laboratory (MEL), MC 98000 (Monaco); Arnold, D. [Physikalisch-Technische Bundesanstalt, Braunschweig, 38116 Germany (Germany); Benmansour, M. [Centre National de l' Energie, des Sciences et des Techniques Nucleaires (CNESTEN), B.P. 1382, R.P.10001, Rabat (Morocco); Bojanowski, R. [Institute of Oceanology, Polish Academy of Sciences, PL-81-712 Sopot (Poland); Carvalho, F.P. [Instituto Tecnologico e Nuclear, Departamento de Proteccao Radiologica e Seguranca Nuclear, P-2685-953 Sacavem (Portugal); Kim, C.K. [Department of Radiological Environmental Assessment, Korea Institute of Nuclear Safety, Yo-song, Taejon 305-600, Korea (Korea); Esposito, M. [Laboratorio di Ingegneria Nucleare, Universita di Bologna, 40136 Bologna (Italy); Gasco, C.L. [CIEMAT-DIAE, Radioecologia del Medio Acuatico, 28040 Madrid (Spain); Ham, G.J. [National Radiological Protection Board, Chilton, Didcot, Oxon, OX11 0RA (United Kingdom); Hegde, A.G. [Environmental Survey Laboratory, Bhabha Atomic Research Center, Tarapur Atomic Power Station, Maharashtra 401 504 (India); Holm, E. [Department of Medical Radiation Physics, Lund University Hospital, 22185 Lund (Sweden); Jaskierowicz, D. [Lab. d' Analyses de Surveillance et d' Expertise de la Marine, Base Navale de Cherbourg, 50115 Cherbourg (France); Kanisch, G. [Federal Research Centre for Fisheries, Institute of Fisheries Ecology, 20539 Hamburg (Germany); Llaurado, M. [Lab. de Radiologia Ambiental, Dept. de Quimica Analitica, Facultat de Quimica, Universitat de Barcelona, 08028 Barcelona (Spain); Le Petit, G. [Commissariat a l' Energie Atomique, DASE/SRCE, 91680 Bruyeres-le-Chatel (France); Maruo, Y. [and others

    2006-10-15

    A certified reference material (CRM) for radionuclides in fish sample IAEA-414 (mixed fish from the Irish Sea and North Seas) is described and the results of the certification process are presented. Nine radionuclides ({sup 4}K, {sup 137}Cs, {sup 232}Th, {sup 234}U, {sup 235}U, {sup 238}U, {sup 238}Pu, {sup 239+24}Pu and {sup 241}Am) were certified for this material. Information on massic activities with 95% confidence intervals is given for six other radionuclides ({sup 9}Sr, {sup 21}Pb({sup 21}Po), {sup 226}Ra, {sup 239}Pu, {sup 24}Pu {sup 241}Pu). Less frequently reported radionuclides ({sup 99}Tc, {sup 129}I, {sup 228}Th, {sup 23}Th and {sup 237}Np) and information on some activity and mass ratios are also included. The CRM can be used for quality assurance/quality control of the analysis of radionuclides in fish sample, for the development and validation of analytical methods and for training purposes. The material is available from IAEA, Vienna, in 100 g units.

  3. Th and U fuel photofission study by NTD for AD-MSR subcritical assembly

    Energy Technology Data Exchange (ETDEWEB)

    Sajo-Bohus, Laszlo; Greaves, Eduardo D.; Barros, Haydn; Pino, Felix; Barrera, Maria T.; Farina, Fulvio [Universidad Simón Bolívar, Nuclear Physics Laboratory, Apdo 89000, Caracas 1080A (Venezuela, Bolivarian Republic of); Davila, Jesus [Física Médica C. A. and Universidad Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of)

    2015-07-23

    During the last decade a considerable effort has been devoted for developing energy generating systems based on advanced nuclear technology within the design concepts of GEN-IV. Thorium base fuel systems such as accelerator driven nuclear reactors are one of the often mentioned attractive and affordable options. Several radiotherapy linear accelerators are on the market and due to their reliability, they could be employed as drivers for subcritical liquid fuel assemblies. Bremsstrahlung photons with energies above 5.5MeV, induce (γ,n) and (e,e’n) reactions in the W-target. Resulting gamma radiation and photo or fission neutrons may be absorbed in target materials such as thorium and uranium isotopes to induce sustained fission or nuclear transmutation in waste radioactive materials. Relevant photo driven and photo-fission reaction cross sections are important for actinides {sup 232}Th, {sup 238}U and {sup 237}Np in the radiotherapy machines energy range of 10-20 MV. In this study we employ passive nuclear track detectors (NTD) to determine fission rates and neutron production rates with the aim to establish the feasibility for gamma and photo-neutron driven subcritical assemblies. To cope with these objectives a 20 MV radiotherapy machine has been employed with a mixed fuel target. Results will support further development for a subcritical assembly employing a thorium containing liquid fuel. It is expected that acquired technological knowledge will contribute to the Venezuelan nuclear energy program.

  4. Dose coefficients and derived guidance and clinical decision levels for contaminated wounds

    Energy Technology Data Exchange (ETDEWEB)

    Bertelli, Luiz [Los Alamos National Laboratory; Toohey, Richard E [ORISE/ORAU; Sugarman, Steven A [ORISE/ORAU; Christensen, Doran R [ORISE/ORAU

    2009-01-01

    The NCRP Wound Model describing the retention of selected radionuclides at the site of a contaminated wound and their uptake into the transfer compartment has been combined with the ICRP element-specific systemic models for those radionuclides to derive dose coefficients for intakes via contaminated wounds. Those coefficients have been used to generate derived guidance levels (i.e., the activity in a wound that would result in an effective dose of 20 or 50 mSv, or in some cases, a committed organ equivalent dose of 500 mSv), and clinical decision levels (i.e., activity levels that would indicate the need for consideration of medical intervention to remove activity from the wound site or administration of decorporation therapy or both), typically set at 5 times the derived guidance levels. Data are provided for the radionuclides commonly encountered at nuclear power plants and nuclear weapons, fuel fabrication or recycling, waste disposal, medical and research facilities. These include: {sup 60}Co, {sup 90}Sr, {sup 99m}Tc, {sup 131}I, {sup 137}Cs, {sup 192}Ir, {sup 210}Po, {sup 226,228}Ra, {sup 228,232}Th, {sup 235,238}U, {sup 237}Np, {sup 238,239}Pu, {sup 241}Am, {sup 242,244}Cm, and {sup 252}Cf.

  5. Th and U fuel photofission study by NTD for AD-MSR subcritical assembly

    Science.gov (United States)

    Sajo-Bohus, Laszlo; Greaves, Eduardo D.; Davila, Jesus; Barros, Haydn; Pino, Felix; Barrera, Maria T.; Farina, Fulvio

    2015-07-01

    During the last decade a considerable effort has been devoted for developing energy generating systems based on advanced nuclear technology within the design concepts of GEN-IV. Thorium base fuel systems such as accelerator driven nuclear reactors are one of the often mentioned attractive and affordable options. Several radiotherapy linear accelerators are on the market and due to their reliability, they could be employed as drivers for subcritical liquid fuel assemblies. Bremsstrahlung photons with energies above 5.5MeV, induce (γ,n) and (e,e'n) reactions in the W-target. Resulting gamma radiation and photo or fission neutrons may be absorbed in target materials such as thorium and uranium isotopes to induce sustained fission or nuclear transmutation in waste radioactive materials. Relevant photo driven and photo-fission reaction cross sections are important for actinides 232Th, 238U and 237Np in the radiotherapy machines energy range of 10-20 MV. In this study we employ passive nuclear track detectors (NTD) to determine fission rates and neutron production rates with the aim to establish the feasibility for gamma and photo-neutron driven subcritical assemblies. To cope with these objectives a 20 MV radiotherapy machine has been employed with a mixed fuel target. Results will support further development for a subcritical assembly employing a thorium containing liquid fuel. It is expected that acquired technological knowledge will contribute to the Venezuelan nuclear energy program.

  6. Measurement of cross-sections of fission reactions induced by neutrons on actinides from the thorium cycle at n-TOF facility; Mesures de sections efficaces de fission induite par neutrons sur des actinides du cycle du thorium a n-TOF

    Energy Technology Data Exchange (ETDEWEB)

    Ferrant, L

    2005-09-01

    In the frame of innovating energy source system studies, thorium fuel cycle reactors are considered. Neutron induced fission cross section on such cycle involved actinides play a role in scenario studies. To feed them, data bases are built with experimental results and nuclear models. For some nuclei, they are not complete or in disagreement. In order to complete these data bases, we have built an original set up, consisting in an alternation of PPACs (Parallel Plate Avalanche Chamber) and ultra - thin targets, which we installed on n-TOF facility. We describe detectors, set up, and the particular care brought to target making and characterization. Fission products in coincidence are detected with precise time measurement and localization with delay line read out method. We contributed, within the n-TOF collaboration, to the CERN brand new intense spallation neutron source characterization, based on time of flight measurement, and we describe its characteristics and performances. We were able to measure such actinide fission cross sections as {sup 232}Th, {sup 234}U, {sup 233}U, {sup 237}Np, {sup 209}Bi, and {sup nat}Pb relative to {sup 235}U et {sup 238}U standards, using an innovative acquisition system. We took advantage of the lame accessible energy field, from 0.7 eV to 1 GeV, combined with the excellent energy resolution in this field. Data treatment and analysis advancement are described to enlighten performance and limits of the obtained results. (author)

  7. Np-237 in peat and lichen in Finland

    DEFF Research Database (Denmark)

    Salminen, S.; Paatero, J.; Roos, Per;

    2009-01-01

    Activity concentrations of 237Np in peat and lichen samples in Finland were determined and contributions from nuclear weapons testing in 1950–1960s and the Chernobyl accident were estimated. 237Np was determined with ICP-MS using 235Np as a tracer. Activity concentrations of 237Np in peat samples...

  8. Preliminary results of calculations for heavy-water nuclear-power-plant reactors employing 235U, 233U, and 232Th as a fuel and meeting requirements of a nonproliferation of nuclear weapons

    Science.gov (United States)

    Ioffe, B. L.; Kochurov, B. P.

    2012-02-01

    A physical design is developed for a gas-cooled heavy-water nuclear reactor intended for a project of a nuclear power plant. As a fuel, the reactor would employ thorium with a small admixture of enriched uranium that contains not more than 20% of 235U. It operates in the open-cycle mode involving 233U production from thorium and its subsequent burnup. The reactor meets the conditions of a nonproliferation of nuclear weapons: the content of fissionable isotopes in uranium at all stages of the process, including the final one, is below the threshold for constructing an atomic bomb, the amount of product plutonium being extremely small.

  9. 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)

  10. Within the framework of the new fuel cycle {sup 232}Th/{sup 233}U, determination of the {sup 233}Pa(n.{gamma}) radiative capture cross section for neutron energies ranging between 0 and 1 MeV; Dans le cadre du nouveau cycle de combustible {sup 232}Th/{sup 233}U, determination de la section efficace de capture radiative {sup 233}Pa(n,{gamma}) pour des energies de neutrons comprises entre 0 et 1 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, S

    2004-10-15

    The Thorium cycle Th{sup 232}/U{sup 233} may face brilliant perspectives through advanced concepts like molten salt reactors or accelerator driven systems but it lacks accurate nuclear data concerning some nuclei. Pa{sup 233} is one of these nuclei, its high activity makes the direct measurement of its radiative neutron capture cross-section almost impossible. This difficulty has been evaded by considering the transfer reaction Th{sup 232}(He{sup 3},p)Pa{sup 234}* in which the Pa{sup 234} nucleus is produced in various excited states according to the amount of energy available in the reaction. The first chapter deals with the thorium cycle and its assets to contribute to the quenching of the fast growing world energy demand. The second chapter gives a detailed description of the experimental setting. A scintillation detector based on deuterated benzene (C{sub 6}D{sub 6}) has been used to counter gamma ray cascades. The third chapter is dedicated to data analysis. In the last chapter we compare our experimental results with ENDF and JENDL data and with computed values from 2 statistical models in the 0-1 MeV neutron energy range. Our results disagree clearly with evaluated data: our values are always above ENDF and JENDL data but tend to near computed values. We have also perform the measurement of the radiative neutron cross-section of Pa{sup 231} for a 110 keV neutron: {sigma}(n,{gamma}) 2.00 {+-} 0.14 barn. (A.C.)

  11. Application of the Spanish methodological approach for biosphere assessment to a generic high-level waste disposal site.

    Science.gov (United States)

    Agüero, A; Pinedo, P; Simón, I; Cancio, D; Moraleda, M; Trueba, C; Pérez-Sánchez, D

    2008-09-15

    A methodological approach which includes conceptual developments, methodological aspects and software tools have been developed in the Spanish context, based on the BIOMASS "Reference Biospheres Methodology". The biosphere assessments have to be undertaken with the aim of demonstrating compliance with principles and regulations established to limit the possible radiological impact of radioactive waste disposals on human health and on the environment, and to ensure that future generations will not be exposed to higher radiation levels than those that would be acceptable today. The biosphere in the context of high-level waste disposal is defined as the collection of various radionuclide transfer pathways that may result in releases into the surface environment, transport within and between the biosphere receptors, exposure of humans and biota, and the doses/risks associated with such exposures. The assessments need to take into account the complexity of the biosphere, the nature of the radionuclides released and the long timescales considered. It is also necessary to make assumptions related to the habits and lifestyle of the exposed population, human activities in the long term and possible modifications of the biosphere. A summary on the Spanish methodological approach for biosphere assessment are presented here as well as its application in a Spanish generic case study. A reference scenario has been developed based on current conditions at a site located in Central-West Spain, to indicate the potential impact to the actual population. In addition, environmental change has been considered qualitatively through the use of interaction matrices and transition diagrams. Unit source terms of (36)Cl, (79)Se, (99)Tc, (129)I, (135)Cs, (226)Ra, (231)Pa, (238)U, (237)Np and (239)Pu have been taken. Two exposure groups of infants and adults have been chosen for dose calculations. Results are presented and their robustness is evaluated through the use of uncertainty and

  12. Coupling of Uranium and Thorium Series Isotope Systematics for Age Determination of Late Pleistocene Zircons using LA-ICP-MS

    Science.gov (United States)

    Sakata, S.; Hirakawa, S.; Iwano, H.; Danhara, T.; Hirata, T.

    2014-12-01

    Zircon U-Th-Pb dating method is one of the most important tools for estimating the duration of magmatism by means of coupling of uranium, actinium and thorium decay series. Using U-Pb dating method, its reliability is principally guaranteed by the concordance between 238U-206Pb and 235U-207Pb ages. In case of dating Quaternary zircons, however, the initial disequilibrium effect on 230Th and 231Pa should be considered. On the other hands, 232Th-208Pb dating method can be a simple but powerful approach for investigating the age of crystallization because of negligible influence from initial disequilibrium effect. We have developed a new correction model for accurate U-Pb dating of the young zircon samples by taking into consideration of initial disequilibrium and a U-Pb vs Th-Pb concordia diagram for reliable age calibration was successfully established. Hence, the U-Th-Pb dating method can be applied to various zircons ranging from Hadean (4,600 Ma) to Quaternary (~50 ka) ages, and this suggests that further detailed information concerning the thermal history of the geological sequences can be made by the coupling of U-Th-Pb, fission track and Ar-Ar ages. In this presentation, we will show an example of U-Th-Pb dating for zircon samples from Sambe Volcano (3 to 100 ka), southwest Japan and the present dating technique using LA-ICP-MS.

  13. Actinide partitioning and transmutation program. Progress report, July 1--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Tedder, D.W.; Blomeke, J.O. (comps.)

    1978-02-01

    In Purex process modifications, two cold runs with mixer-settlers were made on the extraction and stripping of ruthenium and zirconium without the presence of uranium. Efforts in actinide recovery from solids were directed toward the determination of dissolution parameters in various reagents for /sup 241/Am and /sup 239/Pu oxide mixtures, /sup 233/U oxide, /sup 237/Np oxide, /sup 244/Cm oxide, /sup 232/Th oxide, and PuO/sub 2/. Studies in americium-curium recovery with OPIX (oxalate precipitation and ion exchange), Talspeak, and cation exchange chromatography focused on the feasibility of forming oxalate precipitates in continuous systems, the effects of zirconium on Talspeak, and methods for removing solvent degradation products of the Talspeak system. In studies of americium-curium recovery using bidentate extractants, additional distribution coefficients for actinides and other key elements between reduced synthetic LWR waste solution and 30 percent dihexyl-N, N-diethyl-carbamylmethylene phosphonate in diisopropylbenzene were measured. Studies in the americium-curium recovery using inorganic ion exchange media to determine the pH dependence of lanthanide ion affinity for niobate, titanate, and zirconate ion exchange materials have been completed. A modified flowsheet for the extraction of uranium, neptunium, plutonium, americium, and curium from high-level liquid waste is presented. Evaluation of methods for measuring actinides from incinerator ash is continuing. A preliminary evaluation of methods for treatment of salt waste and waste waters was completed. In thermal reactor transmutation studies, waste actinides from an LWR lattice containing mixed uranium-plutonium assemblies were recycled in separate target assemblies. (LK)

  14. OSMOSE program : statistical review of oscillation measurements in the MINERVE reactor R1-UO2 configuration.

    Energy Technology Data Exchange (ETDEWEB)

    Stoven, G.; Klann, R.; Zhong, Z.; Nuclear Engineering Division

    2007-08-28

    The OSMOSE program is a collaboration on reactor physics experiments between the United States Department of Energy and the France Commissariat Energie Atomique. At the working level, it is a collaborative effort between the Argonne National Laboratory and the CEA Cadarache Research Center. The objective of this program is to measure very accurate integral reaction rates in representative spectra for the actinides important to future nuclear system designs, and to provide the experimental data for improving the basic nuclear data files. The main outcome of the OSMOSE measurement program will be an experimental database of reactivity-worth measurements in different neutron spectra for the heavy nuclides. This database can then be used as a benchmark to verify and validate reactor analysis codes. The OSMOSE program (Oscillation in Minerve of isotopes in Eupraxic Spectra) aims at improving neutronic predictions of advanced nuclear fuels through oscillation measurements in the MINERVE facility on samples containing the following separated actinides: {sup 232}Th, {sup 233}U, {sup 234}U, {sup 235}U, {sup 236}U, {sup 238}U, {sup 237}Np, {sup 238}Pu, {sup 239}Pu, {sup 240}Pu, {sup 241}Pu, {sup 242}Pu, {sup 241}Am, {sup 243}Am, {sup 244}Cm, and {sup 245}Cm. The first part of this report provides an overview of the experimental protocol and the typical processing of a series of experimental results which is currently performed at CEA-Cadarache. In the second part of the report, improvements to this technique are presented, as well as the program that was created to process oscillation measurement results from the MINERVE facility in the future.

  15. PRELIMINARY CROSS SECTION AND NU-BAR COVARIANCES FOR WPEC SUBGROUP 26

    Energy Technology Data Exchange (ETDEWEB)

    ROCHMAN,D.

    2007-01-31

    We report preliminary cross section covariances developed for the WPEC Subgroup 26 for 45 out of 52 requested materials. The covariances were produced in 15- and 187-group representations as follows: (1) 36 isotopes ({sup 16}O, {sup 19}F, {sup 23}Na, {sup 27}Al, {sup 28}Si, {sup 52}Cr, {sup 56,56}Fe, {sup 58}Ni, {sup 90,91,92,94}Zr, {sup 166,167,168,170}Er, {sup 206,207,208}Pb, {sup 209}Bi, {sup 233,234,236}U, {sup 237}Np, {sup 238,240,241,242}Pu, {sup 241,242m,243}Am, {sup 242,243,244,245}Cm) were evaluated using the BNL-LANL methodology. For the thermal region and the resolved and unresolved resonance regions, the methodology has been based on the Atlas-Kalman approach, in the fast neutron region the Empire-Kalman method has been used; (2) 6 isotopes ({sup 155,156,157,158,160}Gd and {sup 232}Th) were taken from ENDF/B-VII.0; and (3) 3 isotopes ({sup 1}H, {sup 238}U and {sup 239}Pu) were taken from JENDL-3.3. For 6 light nuclei ({sup 4}He, {sup 6,7}Li, {sup 9}Be, {sup 10}B, {sup 12}C), only partial cross section covariance results were obtained, additional work is needed and they do not report the results here. Likewise, the cross section covariances for {sup 235}U, which they recommend to take from JENDL-3.3, will be included once the multigroup processing is successfully completed. Covariances for the average number of neutrons per fission, total {nu}-bar, are provided for 10 actinides identified as priority by SG26. Further work is needed to resolve some of the issues and to produce covariances for the full set of 52 materials.

  16. Solar r-process-constrained actinide production in neutrino-driven winds of supernovae

    Science.gov (United States)

    Goriely, S.; Janka, H.-Th.

    2016-07-01

    Long-lived radioactive nuclei play an important role as nucleo-cosmochronometers and as cosmic tracers of nucleosynthetic source activity. In particular, nuclei in the actinide region like thorium, uranium, and plutonium can testify to the enrichment of an environment by the still enigmatic astrophysical sources that are responsible for the production of neutron-rich nuclei by the rapid neutron-capture process (r-process). Supernovae and merging neutron-star (NS) or NS-black hole binaries are considered as most likely sources of the r-nuclei. But arguments in favour of one or the other or both are indirect and make use of assumptions; they are based on theoretical models with remaining simplifications and shortcomings. An unambiguous observational determination of a production event is still missing. In order to facilitate searches in this direction, e.g. by looking for radioactive tracers in stellar envelopes, the interstellar medium or terrestrial reservoirs, we provide improved theoretical estimates and corresponding uncertainty ranges for the actinide production (232Th, 235, 236, 238U, 237Np, 244Pu, and 247Cm) in neutrino-driven winds of core-collapse supernovae. Since state-of-the-art supernova models do not yield r-process viable conditions - but still lack, for example, the effects of strong magnetic fields - we base our investigation on a simple analytical, Newtonian, adiabatic and steady-state wind model and consider the superposition of a large number of contributing components, whose nucleosynthesis-relevant parameters (mass weight, entropy, expansion time-scale, and neutron excess) are constrained by the assumption that the integrated wind nucleosynthesis closely reproduces the Solar system distribution of r-process elements. We also test the influence of uncertain nuclear physics.

  17. The Separation Method of Neptunium in Reprocessed Uranium Product by TEVA-UTEVA Column Extraction Chromatography

    Institute of Scientific and Technical Information of China (English)

    JIN; Hua; SU; Yu-lan; YING; Zhe-cong; ZHAO; Sheng-yang

    2012-01-01

    <正>237Np, as a highly toxic nuclide, is limited strictly in the final uranium product of spent nuclear fuel reprocessing plant. Due to the low concentration level of 237Np, which is lower than 2.5 μg/g U, its accurate measurement is one of the most difficult analytical works in

  18. Inorganic, radioisotopic and organic analysis of 241-AP-101 tank waste

    Energy Technology Data Exchange (ETDEWEB)

    SK Fiskum; PR Bredt; JA Campbell; LR Greenwood; OT Farmer; GJ Lumetta; GM Mong; RT Ratner; CZ Soderquist; RG Swoboda; MW Urie; JJ Wagner

    2000-06-28

    Battelle received five samples from Hanford waste tank 241-AP-101, taken at five different depths within the tank. No visible solids or organic layer were observed in the individual samples. Individual sample densities were measured, then the five samples were mixed together to provide a single composite. The composite was homogenized and representative sub-samples taken for inorganic, radioisotopic, and organic analysis. All analyses were performed on triplicate sub-samples of the composite material. The sample composite did not contain visible solids or an organic layer. A subsample held at 10 C for seven days formed no visible solids. The characterization of the 241-AP-101 composite samples included: (1) Inductively-coupled plasma spectrometry for Ag, Al, Ba, Bi, Ca, Cd, Cr, Cu, Fe, K, La, Mg, Mn, Na, Nd, Ni, P, Pb, Pd, Ru, Rh, Si, Sr, Ti, U, Zn, and Zr (Note: Although not specified in the test plan, As, B, Be, Co, Li, Mo, Sb, Se, Sn, Tl, V, W, and Y were also measured and reported for information only) (2) Radioisotopic analyses for total alpha and total beta activities, {sup 3}H, {sup 14}C, {sup 60}Co, {sup 79}Se, {sup 90}Sr, {sup 99}Tc as pertechnetate, {sup 106}Ru/Rh, {sup 125}Sb, {sup 134}Cs, {sup 137}Cs, {sup 152}Eu, {sup 154}Eu, {sup 155}Eu, {sup 238}Pu, {sup 239+240}Pu, {sup 241}Am, {sup 242}Cm, and {sup 243+244}Cm; (3) Inductively-coupled plasma mass spectrometry for {sup 237}Np, {sup 239}Pu, {sup 240}Pu, {sup 99}Tc, {sup 126}Sn, {sup 129}I, {sup 231}Pa, {sup 233}U, {sup 234}U, {sup 235}U, {sup 236}U, {sup 238}U, {sup 241}AMU, {sup 242}AMU, {sup 243}AMU, As, B, Be, Ce, Co, Cs, Eu, I, Li, Mo, Pr, Rb, Sb, Se, Ta, Te, Th, Tl, V, and W; (4) total U by kinetic phosphorescence analysis; (5) Ion chromatography for Cl, F, NO{sub 2}, NO{sub 3}, PO{sub 4}, SO{sub 4}, acetate, formate, oxalate, and citrate; (6) Density, inorganic carbon and organic carbon by two different methods, mercury, free hydroxide, ammonia, and cyanide. The 241-AP-101 composite met all

  19. Analysis of trace neptunium in the vicinity of underground nuclear tests at the Nevada National Security Site.

    Science.gov (United States)

    Zhao, P; Tinnacher, R M; Zavarin, M; Kersting, A B

    2014-11-01

    A high sensitivity analytical method for (237)Np analysis was developed and applied to groundwater samples from the Nevada National Security Site (NNSS) using short-lived (239)Np as a yield tracer and HR magnetic sector ICP-MS. The (237)Np concentrations in the vicinity of the Almendro, Cambric, Dalhart, Cheshire, and Chancellor underground nuclear test locations range from tritium and other non-sorbing radionuclides ((14)C, (36)Cl, (99)Tc and (129)I) as expected. Surprisingly, (237)Np and plutonium ((239,240)Pu) retardation factors are very similar. It is possible that Np(IV) exists under mildly reducing groundwater conditions and exhibits a retardation behavior that is comparable to Pu(IV). Independent of the underlying process, (237)Np is migrating downgradient from NNSS underground nuclear tests at very low but measureable concentrations.

  20. Nuclear Criticality Safety of the DOT 9975 Container for237NpO2Storage, Handling, and Transport

    Energy Technology Data Exchange (ETDEWEB)

    Reed, D.A.

    2003-08-29

    Nuclear criticality safety considerations are presented to address use of the DOT 9975 shipping container for {sup 237}NpO{sub 2}. The DOT 9975 container will be used by multiple DOE sites and contractors. Various of site- and activity-specific NCS and facility safety documents are yet to be developed. For these reasons, an overall assessment of criticality safety of {sup 237}NpO{sub 2}-loaded DOT 9975 containers is considered useful to personnel involved in generating, reviewing, or approving these various documents. It is concluded that inherent container features, the loading per container (maximum of 6 kg {sup 237}Np), and the nuclear physics properties of {sup 237}NpO{sub 2} combine to preclude the potential for a nuclear criticality accident. This conclusion applies to storage, handling, and transport operations involving closed DOT 9975 packages, including credible off-normal conditions that may result in damage to packages during those operations.

  1. Palm content of production metal

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, M.H.; Swift, W.H.

    1959-11-23

    Purpose of this study was to determine the {sup 237}Np input to the Purex process. The {sup 237}Np content of 639 g Pu/ton U irradiated fuel was found to be 1.78 {plus_minus} .09 g/ton of uranium at the 95% confidence level. Standard recovery for the chemical method was 96.7%, 98.0% for the sampling.

  2. Temporal variation and provenance of thorium deposition observed at Tsukuba, Japan.

    Science.gov (United States)

    Hirose, Katsumi; Kikawada, Yoshikazu; Igarashi, Yasuhito

    2012-06-01

    Temporal variations of monthly thorium (Th) deposition observed at Tsukuba, Japan during the period 1990-2007, comparing with plutonium deposition, was studied. The monthly (232)Th deposition as did (239,240)Pu, varied according to season and inter-annually. In particular, (232)Th deposition increased significantly in spring coinciding with Asian dust (Kosa) events. The (230)Th/(232)Th activity ratios vary according to sources and can therefore be used to differentiate between locally derived and remotely derived (232)Th. The (230)Th/(232)Th activity ratios in deposition samples showed large variability with high ratios occurring in early spring. These high (230)Th/(232)Th ratios in deposition can be attributed to local dust storms, especially in early spring, that cause resuspension of soils from cultivated fields which are characterized by high (230)Th/(232)Th activity ratios. The results reveal that both locally and remotely derived (232)Th deposition showed seasonal variations with maxima in spring, although the remotely derived fraction is dominant rather than the locally derived one. The (232)Th deposition maxima later in spring is attributable to the remotely derived fraction, corresponding to the Kosa events. Annual (232)Th deposition exhibited an increasing trend, suggesting the presence of sources other than soil dust such as fly ash from increasing coal burning.

  3. No iron fertilization in the equatorial Pacific Ocean during the last ice age

    Science.gov (United States)

    Costa, K. M.; McManus, J. F.; Anderson, R. F.; Ren, H.; Sigman, D. M.; Winckler, G.; Fleisher, M. Q.; Marcantonio, F.; Ravelo, A. C.

    2016-01-01

    The equatorial Pacific Ocean is one of the major high-nutrient, low-chlorophyll regions in the global ocean. In such regions, the consumption of the available macro-nutrients such as nitrate and phosphate is thought to be limited in part by the low abundance of the critical micro-nutrient iron. Greater atmospheric dust deposition could have fertilized the equatorial Pacific with iron during the last ice age—the Last Glacial Period (LGP)—but the effect of increased ice-age dust fluxes on primary productivity in the equatorial Pacific remains uncertain. Here we present meridional transects of dust (derived from the 232Th proxy), phytoplankton productivity (using opal, 231Pa/230Th and excess Ba), and the degree of nitrate consumption (using foraminifera-bound δ15N) from six cores in the central equatorial Pacific for the Holocene (0-10,000 years ago) and the LGP (17,000-27,000 years ago). We find that, although dust deposition in the central equatorial Pacific was two to three times greater in the LGP than in the Holocene, productivity was the same or lower, and the degree of nitrate consumption was the same. These biogeochemical findings suggest that the relatively greater ice-age dust fluxes were not large enough to provide substantial iron fertilization to the central equatorial Pacific. This may have been because the absolute rate of dust deposition in the LGP (although greater than the Holocene rate) was very low. The lower productivity coupled with unchanged nitrate consumption suggests that the subsurface major nutrient concentrations were lower in the central equatorial Pacific during the LGP. As these nutrients are today dominantly sourced from the Subantarctic Zone of the Southern Ocean, we propose that the central equatorial Pacific data are consistent with more nutrient consumption in the Subantarctic Zone, possibly owing to iron fertilization as a result of higher absolute dust fluxes in this region. Thus, ice-age iron fertilization in the

  4. No iron fertilization in the equatorial Pacific Ocean during the last ice age.

    Science.gov (United States)

    Costa, K M; McManus, J F; Anderson, R F; Ren, H; Sigman, D M; Winckler, G; Fleisher, M Q; Marcantonio, F; Ravelo, A C

    2016-01-28

    The equatorial Pacific Ocean is one of the major high-nutrient, low-chlorophyll regions in the global ocean. In such regions, the consumption of the available macro-nutrients such as nitrate and phosphate is thought to be limited in part by the low abundance of the critical micro-nutrient iron. Greater atmospheric dust deposition could have fertilized the equatorial Pacific with iron during the last ice age--the Last Glacial Period (LGP)--but the effect of increased ice-age dust fluxes on primary productivity in the equatorial Pacific remains uncertain. Here we present meridional transects of dust (derived from the (232)Th proxy), phytoplankton productivity (using opal, (231)Pa/(230)Th and excess Ba), and the degree of nitrate consumption (using foraminifera-bound δ(15)N) from six cores in the central equatorial Pacific for the Holocene (0-10,000 years ago) and the LGP (17,000-27,000 years ago). We find that, although dust deposition in the central equatorial Pacific was two to three times greater in the LGP than in the Holocene, productivity was the same or lower, and the degree of nitrate consumption was the same. These biogeochemical findings suggest that the relatively greater ice-age dust fluxes were not large enough to provide substantial iron fertilization to the central equatorial Pacific. This may have been because the absolute rate of dust deposition in the LGP (although greater than the Holocene rate) was very low. The lower productivity coupled with unchanged nitrate consumption suggests that the subsurface major nutrient concentrations were lower in the central equatorial Pacific during the LGP. As these nutrients are today dominantly sourced from the Subantarctic Zone of the Southern Ocean, we propose that the central equatorial Pacific data are consistent with more nutrient consumption in the Subantarctic Zone, possibly owing to iron fertilization as a result of higher absolute dust fluxes in this region. Thus, ice-age iron fertilization in the

  5. 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

  6. Corrigendum to "Deep water provenance and dynamics of the (de)glacial Atlantic meridional overturning circulation" [Earth Planet. Sci. Lett. 445 (2016) 68-78

    Science.gov (United States)

    Lippold, Jörg; Gutjahr, Marcus; Blaser, Patrick; Christner, Emanuel; de Carvalho Ferreira, Maria Luiza; Mulitza, Stefan; Christl, Marcus; Wombacher, Frank; Böhm, Evelyn; Antz, Benny; Cartapanis, Olivier; Vogel, Hendrik; Jaccard, Samuel L.

    2017-01-01

    We have reconstructed past modes of the Atlantic Meridional Overturning Circulation (AMOC) by combining two sedimentary proxies, Nd isotopes (εNd) and the 231Pa/230Th ratio over the last deglaciation. Combined down-core 231Pa/230Th and εNd records from six Atlantic Ocean sediment archives are presented (Lippold et al., 2016).

  7. Neptunium Transport Behavior in the Vicinity of Underground Nuclear Tests at the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, P; Tinnacher, R M; Zavarin, M; Williams, R W; Kersting, A B

    2010-12-03

    We used short lived {sup 239}Np as a yield tracer and state of the art magnetic sector ICP-MS to measure ultra low levels of {sup 237}Np in a number of 'hot wells' at the Nevada National Security Site (NNSS), formerly known as the Nevada Test Site (NTS). The results indicate that {sup 237}Np concentrations at the Almendro, Cambric, Dalhart, Cheshire and Chancellor sites, are in the range of 3 x 10{sup -5} to 7 x 10{sup -2} pCi/L and well below the MCL for alpha emitting radionuclides (15 pCi/L) (EPA, 2009). Thus, while Np transport is believed to occur at the NNSS, activities are expected to be well below the regulatory limits for alpha-emitting radionuclides. We also compared {sup 237}Np concentration data to other radionuclides, including tritium, {sup 14}C, {sup 36}Cl, {sup 99}Tc, {sup 129}I, and plutonium, to evaluate the relative {sup 237}Np transport behavior. Based on isotope ratios relative to published unclassified Radiologic Source Terms (Bowen et al., 1999) and taking into consideration radionuclide distribution between melt glass, rubble and groundwater (IAEA, 1998), {sup 237}Np appears to be substantially less mobile than tritium and other non-sorbing radionuclides, as expected. However, this analysis also suggests that {sup 237}Np mobility is surprisingly similar to that of plutonium. The similar transport behavior of Np and Pu can be explained by one of two possibilities: (1) Np(IV) and Pu(IV) oxidation states dominate under mildly reducing NNSS groundwater conditions resulting in similar transport behavior or (2) apparent Np transport is the result of transport of its parent {sup 241}Pu and {sup 241}Am isotopes and subsequent decay to {sup 237}Np. Finally, measured {sup 237}Np concentrations were compared to recent Hydrologic Source Term (HST) models. The 237Np data collected from three wells in Frenchman Flat (RNM-1, RNM-2S, and UE-5n) are in good agreement with recent HST transport model predictions (Carle et al., 2005). The agreement

  8. Determination of specific activity of 230Th in uranium ore samples

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new method suitable for determining specific activity of 230Th in uranium ore samples is built. The method is characterized by adding the 230Th/ 232Th standard dilution agent with lower activity ratio (Its 230Th/ 232Th activity ratio and 230Th have been known) to the samples and using isotopic dilution analysis. The method can be applied to analyses of 230Th specific activity in various 230Th/ 232Th activity ratio samples. The precision can also be improved.

  9. Studies of Np and Pu in the marine environment of Swedish-Danish waters and the North Atlantic Ocean.

    Science.gov (United States)

    Lindahl, Patric; Roos, Per; Holm, Elis; Dahlgaard, Henning

    2005-01-01

    The long-lived anthropogenic radionuclides (237)Np, (239)Pu and (240)Pu were determined in marine environmental samples (seaweed and seawater) collected from Swedish-Danish waters and the North Atlantic Ocean at various locations on different occasions during the period 1991-2001. The measurements were performed with sector field Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and conventional alpha spectrometry. The (237)Np activity concentrations in Fucus vesiculosus and surface seawater from the Swedish west coast and Danish waters ranged from 0.16+/-0.02 to 1.02+/-0.09 mBq kg(-1) (dry weight) and 0.65+/-0.02 to 1.69+/-0.02 mBq m(-3), respectively, depending on the location and sampling year. Most of the (237)Np in these waters is believed to originate from the Sellafield nuclear reprocessing plant, with some contribution from global fallout. The (240)Pu/(239)Pu atomic ratios in F. vesiculosus samples are reported in this study with an overall average of 0.17+/-0.03. The (237)Np and (239)Pu activity concentrations observed in surface seawater collected in North Atlantic waters ranged from 0.16+/-0.01 to 0.62+/-0.08 mBq m(-3) and from 0.64+/-0.05 to 4.27+/-0.08 mBq m(-3), respectively, and the (237)Np/(239)Pu atomic ratios were a good indicator of conservative behaviour of Np in marine waters.

  10. Prompt Fission Neutron Spectra of Actinides

    Energy Technology Data Exchange (ETDEWEB)

    Capote, R; Chen, Y J; Hambsch, F J; Kornilov, N V; Lestone, J P; Litaize, O; Morillon, B; Neudecker, D; Oberstedt, S; Ohsawa, T; Smith, D. L.

    2016-01-01

    The energy spectrum of prompt neutrons emitted in fission (PFNS) plays a very important role in nuclear science and technology. A Coordinated Research Project (CRP) “Evaluation of Prompt Fission Neutron Spectra of Actinides”was established by the IAEA Nuclear Data Section in 2009, with the major goal to produce new PFNS evaluations with uncertainties for actinide nuclei. The following technical areas were addressed: (i) experiments and uncertainty quantification (UQ): New data for neutron-induced fission of 233U, 235U, 238U, and 239Pu have been measured, and older data have been compiled and reassessed. There is evidence from the experimental work of this CRP that a very small percentage of neutrons emitted in fission are actually scission neutrons; (ii) modeling: The Los Alamos model (LAM) continues to be the workhorse for PFNS evaluations. Monte Carlo models have been developed that describe the fission phenomena microscopically, but further development is needed to produce PFNS evaluations meeting the uncertainty targets; (iii) evaluation methodologies: PFNS evaluations rely on the use of the least-squares techniques for merging experimental and model data. Considerable insight was achieved on how to deal with the problem of too small uncertainties in PFNS evaluations. The importance of considering that all experimental PFNS data are “shape” data was stressed; (iv) PFNS evaluations: New evaluations, including covariance data, were generated for major actinides including 1) non-model GMA evaluations of the 235U(nth,f), 239Pu(nth,f), and 233U(nth,f) PFNS based exclusively on experimental data (0.02 ≤ E ≤ 10 MeV), which resulted in PFNS average energies E of 2.00±0.01, 2.073±0.010, and 2.030±0.013 MeV, respectively; 2) LAM evaluations of neutron-induced fission spectra on uranium and plutonium targets with improved UQ for incident energies from thermal up to 30 MeV; and 3) Point-by-Point calculations for 232Th, 234U and 237Np targets; and (v) data

  11. Criticality experiments and benchmarks for cross section evaluation: the neptunium case

    Directory of Open Access Journals (Sweden)

    Duran I.

    2013-03-01

    Full Text Available The 237Np neutron-induced fission cross section has been recently measured in a large energy range (from eV to GeV at the n_TOF facility at CERN. When compared to previous measurement the n_TOF fission cross section appears to be higher by 5-7% beyond the fission threshold. To check the relevance of n_TOF data, we apply a criticality experiment performed at Los Alamos with a 6 kg sphere of 237Np, surrounded by enriched uranium 235U so as to approach criticality with fast neutrons. The multiplication factor ke f f of the calculation is in better agreement with the experiment (the deviation of 750 pcm is reduced to 250 pcm when we replace the ENDF/B-VII.0 evaluation of the 237Np fission cross section by the n_TOF data. We also explore the hypothesis of deficiencies of the inelastic cross section in 235U which has been invoked by some authors to explain the deviation of 750 pcm. With compare to inelastic large distortion calculation, it is incompatible with existing measurements. Also we show that the v of 237Np can hardly be incriminated because of the high accuracy of the existing data. Fission rate ratios or averaged fission cross sections measured in several fast neutron fields seem to give contradictory results on the validation of the 237Np cross section but at least one of the benchmark experiments, where the active deposits have been well calibrated for the number of atoms, favors the n_TOF data set. These outcomes support the hypothesis of a higher fission cross section of 237Np.

  12. Validation of Cross Sections with Criticality Experiment and Reaction Rates: the Neptunium Case

    Science.gov (United States)

    Leong, L. S.; Tassan-Got, L.; Audouin, L.; Berthier, B.; Le Naour, C.; Stéphan, C.; Paradela, C.; Tarrío, D.; Duran, I.

    2014-04-01

    The 237Np neutron-induced fission cross section has been recently measured in a large energy range (from eV to GeV) at the n_TOF facility at CERN. When compared to previous measurements the n_TOF fission cross section appears to be higher by 5-7% beyond the fission threshold. To check the relevance of the n_TOF data, we considered a criticality experiment performed at Los Alamos with a 6 kg sphere of 237Np, surrounded by uranium highly enriched in 235U so as to approach criticality with fast neutrons. The multiplication factor keff of the calculation is in better agreement with the experiment when we replace the ENDF/B-VII.0 evaluation of the 237Np fission cross section by the n_TOF data. We also explored the hypothesis of deficiencies of the inelastic cross section in 235U which has been invoked by some authors to explain the deviation of 750 pcm. The large modification needed to reduce the deviation seems to be incompatible with existing inelastic cross section measurements. Also we show that the νbar of 237Np can hardly be incriminated because of the high accuracy of the existing data. Fission rate ratios or averaged fission cross sections measured in several fast neutron fields seem to give contradictory results on the validation of the 237Np cross section but at least one of the benchmark experiments, where the active deposits have been well calibrated for the number of atoms, favors the n_TOF data set. These outcomes support the hypothesis of a higher fission cross section of 237Np.

  13. Criticality experiments and benchmarks for cross section evaluation: the neptunium case

    Science.gov (United States)

    Leong, L. S.; Tassan-Got, L.; Audouin, L.; Paradela, C.; Wilson, J. N.; Tarrio, D.; Berthier, B.; Duran, I.; Le Naour, C.; Stéphan, C.

    2013-03-01

    The 237Np neutron-induced fission cross section has been recently measured in a large energy range (from eV to GeV) at the n_TOF facility at CERN. When compared to previous measurement the n_TOF fission cross section appears to be higher by 5-7% beyond the fission threshold. To check the relevance of n_TOF data, we apply a criticality experiment performed at Los Alamos with a 6 kg sphere of 237Np, surrounded by enriched uranium 235U so as to approach criticality with fast neutrons. The multiplication factor ke f f of the calculation is in better agreement with the experiment (the deviation of 750 pcm is reduced to 250 pcm) when we replace the ENDF/B-VII.0 evaluation of the 237Np fission cross section by the n_TOF data. We also explore the hypothesis of deficiencies of the inelastic cross section in 235U which has been invoked by some authors to explain the deviation of 750 pcm. With compare to inelastic large distortion calculation, it is incompatible with existing measurements. Also we show that the v of 237Np can hardly be incriminated because of the high accuracy of the existing data. Fission rate ratios or averaged fission cross sections measured in several fast neutron fields seem to give contradictory results on the validation of the 237Np cross section but at least one of the benchmark experiments, where the active deposits have been well calibrated for the number of atoms, favors the n_TOF data set. These outcomes support the hypothesis of a higher fission cross section of 237Np.

  14. Method for Determination of Neptunium in Large-Sized Urine Samples Using Manganese Dioxide Coprecipitation and 242Pu as Yield Tracer

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2013-01-01

    A novel method for bioassay of large volumes of human urine samples using manganese dioxide coprecipitation for preconcentration was developed for rapid determination of 237Np. 242Pu was utilized as a nonisotopic tracer to monitor the chemical yield of 237Np. A sequential injection extraction...... to 100% and high separation capacity of processing up to 5 L of human urine samples. The MnO2 coprecipitation process is simple and straightforward in which a batch (8–12) of samples can be pretreated within 4 h (i.e.,

  15. Uptake of radionuclide thorium by twelve native plants grown in uranium mill tailings soils from south part of China

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Xun, E-mail: m13836295186@163.com

    2016-08-01

    Highlights: • Screen dominant plants grown in uranium mill tailings soils. • Quantify the content of {sup 232}Th of soil samples from uranium mill tailings. • Quantify the transfer factor, bioconcentration factor and phytoremediation factor. • Screen out the plant species capable of remediating radionuclide contaminated soils. • Guide the reuse of study area in future. - Abstract: The concentrations of thorium ({sup 232}Th) in soil from a uranium mill tailings repository in South China were analyzed. The results showed that all the soil samples were acidic and the concentrations of {sup 232}Th in all the soil samples were more than the natural radionuclide content in soil of China. Through the field investigation, twelve kinds of dominant plants were discovered. The total quantity of {sup 232}Th in the whole plant is highest in rice flat sedge. We also found that Miscanthus floridulus has the greatest transfer factor (TF) for {sup 232}Th, rice flat sedge has the greatest bioconcentration factor (BF) for {sup 232}Th. At the mean time, M. floridulus has the greatest phytoremediation factor (PF) for {sup 232}Th. On the basis of the above conclusions and the definition for hyperaccumulator, rice flat sedge and M. floridulus could be the candidates of phytoremediation for radionuclide {sup 232}Th in the soil.

  16. Application of ICP-MS for the assessment of thorium excretion in urine.

    Science.gov (United States)

    Roth, P; Werner, E; Wendler, I; Schramel, P

    1996-01-01

    A method for rapid and sensitive determination of thorium in urine by inductively coupled plasma mass spectometry (ICP-MS) is described. The method is sufficiently sensitive to detect 1 ng/L 232Th in urine without any sample preparation. The mean urinary 232Th excretion in 23 unexposed subjects was 6.2 +/- 3.3 ng/d.

  17. Feasibility studies for assessing internal exposure to {sup 233}U

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, D.J.; Sharma, R.C.; Ramanujam, A.; Haridasan, T.K.; Sawant, P.D.; Rathinam, M

    2003-07-01

    The potential internal occupational exposure encountered as a consequence of the {sup 232}Th-{sup 233}U fuel cycle are likely to arise predominantly from the inhalation of {sup 232}Th, {sup 233}U and ({sup 232}Th + {sup 233}U) compounds of absorption Types M and S. In the past, although direct and indirect methods for assessments of internal exposure to {sup 232}Th and its daughters were developed, standardised and employed, no such attempts have been made with regard to {sup 233}U and {sup 233}U+{sup 232}Th. Therefore, feasibility studies for assessing internal exposures to {sup 233}U have been conducted using three methods: urine bioassay, in vivo counting and measurement of thoron gas in the exhaled breath of a worker. This paper describes details of these studies and discusses the results obtained. (author)

  18. Rapid and simultaneous determination of neptunium and plutonium isotopes in environmental samples by extraction chromatography using sequential injection analysis and ICP-MS

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2010-01-01

    This paper reports an automated analytical method for rapid and simultaneous determination of plutonium isotopes (239Pu and 240Pu) and neptunium (237Np) in environmental samples. An extraction chromatographic column packed with TrisKem TEVA® resin was incorporated in a sequential injection (SI...

  19. Study on behavior of long-lived radionuclides in soil environment

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Shigemitsu; Watanabe, Hitoshi; Katagiri, Hiromi; Akatsu, Yasuo [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works

    1996-04-01

    Distribution of {sup 99}Tc, {sup 239,240}Pu and {sup 237}Np in soil in Japan was measured. Dependency of concentration on physical and chemical properties of soil was studied. High sensitivity inductively coupled plasma mass spectroscopy was applied to the quantitative analysis of long-lived radionuclides. (J.P.N.)

  20. Thorium isotopes in human tissues

    Energy Technology Data Exchange (ETDEWEB)

    Stehney, A.F.; Lucas, H.F.

    1991-12-31

    Concentrations of {sup 232}Th and activity ratios of {sup 228}Th to {sup 232}Th and {sup 230}Th to {sup 232}Th were determined in autopsy samples from five former employees of a thorium refinery. The ranges of {sup 232}Th activity concentrations (mBq g{sup {minus}1}) were 0.17--94 in lungs, 3.9--1210 in pulmonary lymph nodes, 0.14--1.19 in bones, 0.015--0.68 in liver, 0.97--5.8 in spleen, and 0.009--0.068 in kidneys. These concentrations are 10 to 1000 times greater than have been reported for persons not occupationally exposed to Th. In most of the samples, the ratios of {sup 230}Th to {sup 232}Th and {sup 228}Th to {sup 232}Th activity at death of the subject were 0.1--0.2 and 0.2--0.4, respectively. Thorium-228 to {sup 228}Ra activity ratios ({plus_minus} standard errors) of 0.86 {plus_minus} 0.11 in lungs and 1.18 {plus_minus} 0.13 in lymph nodes of one subject were obtained by calculation from ratios of {sup 228}Th to {sup 232}Th.

  1. Sequential injection approach for simultaneous determination of ultratrace plutonium and neptunium in urine with accelerator mass spectrometry.

    Science.gov (United States)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per; Lachner, Johannes; Christl, Marcus; Xu, Yihong

    2013-09-17

    An analytical method was developed for simultaneous determination of ultratrace level plutonium (Pu) and neptunium (Np) using iron hydroxide coprecipitation in combination with automated sequential injection extraction chromatography separation and accelerator mass spectrometry (AMS) measurement. Several experimental parameters affecting the analytical performance were investigated and compared including sample preboiling operation, aging time, amount of coprecipitating reagent, reagent for pH adjustment, sedimentation time, and organic matter decomposition approach. The overall analytical results show that preboiling and aging are important for obtaining high chemical yields for both Pu and Np, which is possibly related to the aggregation and adsorption behavior of organic substances contained in urine. Although the optimal condition for Np and Pu simultaneous determination requires 5-day aging time, an immediate coprecipitation without preboiling and aging could also provide fairly satisfactory chemical yields for both Np and Pu (50-60%) with high sample throughput (4 h/sample). Within the developed method, (242)Pu was exploited as chemical yield tracer for both Pu and Np isotopes. (242)Pu was also used as a spike in the AMS measurement for quantification of (239)Pu and (237)Np concentrations. The results show that, under the optimal experimental condition, the chemical yields of (237)Np and (242)Pu are nearly identical, indicating the high feasibility of (242)Pu as a nonisotopic tracer for (237)Np determination in real urine samples. The analytical method was validated by analysis of a number of urine samples spiked with different levels of (237)Np and (239)Pu. The measured values of (237)Np and (239)Pu by AMS exhibit good agreement (R(2) ≥ 0.955) with the spiked ones confirming the reliability of the proposed method.

  2. Studies of Np and Pu in the marine environment of Swedish-Danish waters and the North Atlantic Ocean

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, Patric [Department of Radiation Physics, Lund University Hospital, SE-221 85 Lund (Sweden) and Korea Ocean Research and Development Institute, Ansan P.O. Box 29, Seoul 425-600 (Korea, Republic of)]. E-mail: patriclindahl@yahoo.com; Roos, Per [Risoe National Laboratory, P.O. Box 49, DK-4000 Roskilde (Denmark); Holm, Elis [Department of Radiation Physics, Lund University Hospital, SE-221 85 Lund (Sweden); Risoe National Laboratory, P.O. Box 49, DK-4000 Roskilde (Denmark); Dahlgaard, Henning [Risoe National Laboratory, P.O. Box 49, DK-4000 Roskilde (Denmark)

    2005-07-01

    The long-lived anthropogenic radionuclides {sup 237}Np, {sup 239}Pu and {sup 240}Pu were determined in marine environmental samples (seaweed and seawater) collected from Swedish-Danish waters and the North Atlantic Ocean at various locations on different occasions during the period 1991-2001. The measurements were performed with sector field Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and conventional alpha spectrometry. The {sup 237}Np activity concentrations in Fucus vesiculosus and surface seawater from the Swedish west coast and Danish waters ranged from 0.16 {+-} 0.02 to 1.02 {+-} 0.09 mBq kg{sup -1} (dry weight) and 0.65 {+-} 0.02 to 1.69 {+-} 0.02 mBq m{sup -3}, respectively, depending on the location and sampling year. Most of the {sup 237}Np in these waters is believed to originate from the Sellafield nuclear reprocessing plant, with some contribution from global fallout. The {sup 240}Pu/{sup 239}Pu atomic ratios in F. vesiculosus samples are reported in this study with an overall average of 0.17 {+-} 0.03. The {sup 237}Np and {sup 239}Pu activity concentrations observed in surface seawater collected in North Atlantic waters ranged from 0.16 {+-} 0.01 to 0.62 {+-} 0.08 mBq m{sup -3} and from 0.64 {+-} 0.05 to 4.27 {+-} 0.08 mBq m{sup -3}, respectively, and the {sup 237}Np/{sup 239}Pu atomic ratios were a good indicator of conservative behaviour of Np in marine waters.

  3. 一种用于铀同位素比值α能谱分析的磷化膜制源新技术%A New Source-preparation Technique of Phosphate Conversion Coating Used in the Determination of Uranium Isotope Ratio by Alpha Spectrometry

    Institute of Scientific and Technical Information of China (English)

    王哲; 王玉学; 郭冬发; 付琳; 黄秋红; 孙伟; 陈春军

    2016-01-01

    A new source-preparation technique of uranium phosphate conversion coating was developed for the determination of uranium isotope ratio by alpha spectrometry. It was found experimentally that under the conditions of 3.14 cm2 Ni-foil,0.5 mol/L HCl,2.5 mol/L NaCl ,0.08 mol/L KH 2 PO 4 ,20 g/L ascorbic acid ,25 mL initial solution,90℃ constant experiment temperature,1 60 r/min vibration frequency ,20 mm vibration amplitude,and 70min deposition time ,uranium less than 200 μg can be quantitatively and spontaneously converted into phosphorization film on Ni-foil. Compared to the tradi-tional source-preparation technique of electro-deposition,the technique of uranium phosphate conversion coating has the advantage of simple in electro-deposition device, easy in operation, high working-efficiency ,no interference in measuring lots of coexisting radionuclides such as 2 3 2 Th ,2 30 Th,22 6 Ra,2 3 1 Pa and so on in phosphating solution. The total spike recovery rate of uranium reaches 100% nearly,and the spectrum resolution is good in determing uranium isotope ratio by alpha spectrometry.%研发了一种用于铀同位素比值α能谱分析的磷化膜制源新技术.试验发现,当镍镀片面积为3.14 cm2,盐酸浓度为0.5 mol/L ,氯化钠浓度为2.5 mol/L ,磷酸二氢钾浓度为0.08 mol/L,抗坏血酸浓度为20 g/L,溶液体积为25 mL,恒温90℃,振荡速率为160次/min,振程20 mm 时,磷化膜制源70 min,200μg 以下的铀可在镍箔上定量转化为磷化膜.与传统的电沉积制源技术相比较,应用磷化膜制源技术进行测量源制备时无需电沉积装置,制源过程简单快速,工效高,大量共存的232 Th 、230 Th、226 Ra、231 Pa 等核素均不产生干扰,铀的全程回收率接近100%,α能谱峰分辨率较好.

  4. Interactions of secondary particles with thorium samples in the setup QUINTA irradiated with 6 GeV deuterons

    Energy Technology Data Exchange (ETDEWEB)

    Khushvaktov, J., E-mail: khushvaktov@jinr.ru [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute of Nuclear Physics ASRU, Tashkent (Uzbekistan); Adam, J. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Nuclear Physics Institute ASCR PRI (Czech Republic); Baldin, A.A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute for Advanced Studies “OMEGA”, Dubna (Russian Federation); Chilap, V.V. [Center of Physical and Technical Projects “Atomenergomash”, Moscow (Russian Federation); Furman, V.I.; Sagimbaeva, F.; Solnyshkin, A.A.; Stegailov, V.I.; Tichy, P.; Tsoupko-Sitnikov, V.M.; Tyutyunnikov, S.I.; Vespalec, R. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Vrzalova, J. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Nuclear Physics Institute ASCR PRI (Czech Republic); Yuldashev, B.S. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Institute of Nuclear Physics ASRU, Tashkent (Uzbekistan); Wagner, V. [Nuclear Physics Institute ASCR PRI (Czech Republic); Zavorka, L.; Zeman, M. [Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2016-08-15

    The natural uranium assembly, QUINTA, was irradiated with 6 GeV deuterons. The {sup 232}Th samples were placed at the central axis of the setup QUINTA. The spectra of gamma rays emitted by the activated {sup 232}Th samples have been analysed and more than one hundred nuclei produced have been identified. For each of those products, reaction rates have been determined. The ratio of the weight of produced {sup 233}U to {sup 232}Th is presented. Experimental results were compared with the results of Monte Carlo simulations by FLUKA code.

  5. Interactions of secondary particles with thorium samples in the setup QUINTA irradiated with 6 GeV deuterons

    Science.gov (United States)

    Khushvaktov, J.; Adam, J.; Baldin, A. A.; Chilap, V. V.; Furman, V. I.; Sagimbaeva, F.; Solnyshkin, A. A.; Stegailov, V. I.; Tichy, P.; Tsoupko-Sitnikov, V. M.; Tyutyunnikov, S. I.; Vespalec, R.; Vrzalova, J.; Yuldashev, B. S.; Wagner, V.; Zavorka, L.; Zeman, M.

    2016-08-01

    The natural uranium assembly, QUINTA, was irradiated with 6 GeV deuterons. The 232Th samples were placed at the central axis of the setup QUINTA. The spectra of gamma rays emitted by the activated 232Th samples have been analysed and more than one hundred nuclei produced have been identified. For each of those products, reaction rates have been determined. The ratio of the weight of produced 233U to 232Th is presented. Experimental results were compared with the results of Monte Carlo simulations by FLUKA code.

  6. Neutron scattering studies in the actinide region

    Energy Technology Data Exchange (ETDEWEB)

    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 {sup 14}N, {sup 181}Ta, {sup 232}Th, {sup 238}U and {sup 239}Pu; Prompt fission spectra for {sup 232}Th, {sup 235}U, {sup 238}U and {sup 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.

  7. Neutron scattering studies in the actinide region. Progress report, August 1, 1988--July 31, 1991

    Energy Technology Data Exchange (ETDEWEB)

    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 {sup 14}N, {sup 181}Ta, {sup 232}Th, {sup 238}U and {sup 239}Pu; Prompt fission spectra for {sup 232}Th, {sup 235}U, {sup 238}U and {sup 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.

  8. Field test of nuclide migration in bentonite-based materials at aerated zone. Cooperative research program on field migration test between CIRP and JAERI

    Energy Technology Data Exchange (ETDEWEB)

    Fan Zhiwen; Cui Anxi; Gu Cunli [China Inst. for Radiation Protection, Taiyuan, Shanxi (China)] [and others

    2002-03-01

    A field test was jointly conducted by China Institute for Radiation Protection (CIRP) and Japan Atomic Energy Research Institute (JAERI) to explore moisture movement with Br{sup -} and migration of radioactive tracer {sup 237}Np, {sup 238}Pu and {sup 90}Sr in bentonite-based materials at aerated zone. The test ran under two rainfall conditions, the artificial rainfall with sprinkling density of 15 mm/d and 5 mm/hr, and the natural rainfall. Tracing test of Br{sup -} implies that there does have water going through the bentonite specimen. However, the curves are very complex and further work need be conducted to quantify this movement. {sup 238}Pu has no observable movement during the test period under either rainfall conditions, and {sup 237}Np has very short movement dominated by diffusion. Bentonite-based materials are effective to retard nuclide migration. (author)

  9. The Geochemical Behaviour of Tc, Np, and Pu in Spent Nuclear Fuel in an Oxidizing Environment

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Edgar C.; Hanson, Brady D.; McNamara, Bruce K.; R. Giere and P. Stille

    2004-10-01

    Studies at the Nopal and Shinkolowbwe uranium deposits show that the primary uraninite (UO2) altered to a suite of secondary uranyl minerals similar to those observed in corrosion tests with uranium oxide . Although the Nopal I deposit tells us something about the possible fate of uranium, it tells us little about the likely fate of the important long-lived radionuclides; iodine (129I), cesium (135Cs), technetium (99Tc), neptunium (237Np), and plutonium (239Pu). Most performance assessment (PA) models, assume conservatively, that as the UO2 matrix corrodes, the key radionuclides (129I, 99Tc, 237Np, and 239Pu) will be released congruently. In so doing, these PA models force increased reliance on human engineered barriers.

  10. Application of off/on line sequential injection system with high resolution ICP-MS to measurement radionuclides in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Chang-Kyu Kim (IAEA, Physics, Chemistry and Instrumentation Lab., Agency' s Laboratories, Seibersdorf (Austria))

    2010-03-15

    A sequential injection system was developed, which can be widely used for the separation and preconcentration of analytes from diverse environmental samples. The system enables the separation time to be shortened by maintaining a constant flow rate of solution and by avoiding clogging or bubbling in a chromatographic column. The SI system was successfully applied to the separation of 237Np and Pu isotopes in IAEA reference materials and environmental samples, and to the sequential separation of 210Po and 210Pb in a phosphogypsum candidate reference material. The replicate analysis results of 237Np, 239+240Pu 210Po and 210Pb in some IAEA reference materials using the SI system associated with HR-ICP-MS, alpha-spectrometry and LSC are in good agreement with the recommended value within 5% of standard deviation. The SI system enabled a halving of the separation time required for radionuclides. (author)

  11. Magnetic sublattices in Np2Co17 and Np2Ni17

    Science.gov (United States)

    Colineau, E.; Hen, A.; Sanchez, J.-P.; Griveau, J.-C.; Magnani, N.; Eloirdi, R.; Halevy, I.; Gaczyński, P.; Orion, I.; Shick, A. B.; Caciuffo, R.

    2016-12-01

    Rare-earth-based compounds R2T17 (R=Rare earth; T=Transition metal) have been extensively studied and developed for applications as permanent magnets. The actinide-based analogues, however, are much less documented and we report here about the magnetic properties of Np2Co17 and Np2Ni17, as inferred from 237Np Mössbauer spectroscopy, the best resonance in actinides, and specific heat.

  12. Average resonance parameters evaluation for actinides

    Energy Technology Data Exchange (ETDEWEB)

    Porodzinskij, Yu.V.; Sukhovitskij, E.Sh. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    New evaluated <{Gamma}{sub n}{sup 0}> and values for {sup 238}U, {sup 237}Np, {sup 243}Cm, {sup 245}Cm, {sup 246}Cm and {sup 241}Am nuclei in the resolved resonance region are presented. The applied method based on the idea that experimental resonance missing results in correlated changes of reduced neutron widths and level spacings distributions is discussed. (author)

  13. Analysis of the evaluated data discrepancies for minor actinides and development of improved evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Ignatyuk, A. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    The work is directed on a compilation of experimental and evaluated data available for neutron induced reaction cross sections on {sup 237}Np, {sup 241}Am, {sup 242m}Am and {sup 243}Am isotopes, on the analysis of the old data and renormalizations connected with changes of standards and on the comparison of experimental data with theoretical calculation. Main results of the analysis performed by now are presented in this report. (J.P.N.)

  14. Measurements of Fission Cross Sections of Actinides

    CERN Multimedia

    Wiescher, M; Cox, J; Dahlfors, M

    2002-01-01

    A measurement of the neutron induced fission cross sections of $^{237}$Np, $^{241},{243}$Am and of $^{245}$Cm is proposed for the n_TOF neutron beam. Two sets of fission detectors will be used: one based on PPAC counters and another based on a fast ionization chamber (FIC). A total of 5x10$^{18}$ protons are requested for the entire fission measurement campaign.

  15. Modelling of reaction cross sections and prompt neutron emission

    Science.gov (United States)

    Hambsch, F.-J.; Tudora, A.; Oberstedt, S.

    2010-10-01

    Accurate nuclear data concerning reaction cross sections and the emission of prompt fission neutrons (i.e. multiplicity and spectra) as well as other fission fragment data are of great importance for reactor physics design, especially for the new Generation IV nuclear energy systems. During the past years for several actinides (238U(n, f) and 237Np(n, f)) both the reaction cross sections and prompt neutron multiplicities and spectra have been calculated within the frame of the EFNUDAT project.

  16. Moessbauer spectroscopy with actinide elements

    Energy Technology Data Exchange (ETDEWEB)

    Potzel, W.; Moser, J.; Asch, L.; Kalvius, G.M. (Technische Univ. Muenchen, Garching (Germany, F.R.)

    1983-01-01

    Although formally equivalent to the lanthanide (4f) elements, the light actinides show a much more varied behaviour due to the larger spatial extent and ionizability of the 5f electrons. The application of Moessbauer spectroscopy for the determination of electronic properties of the actinides is outlined. Emphasis is put on high pressure Moessbauer experiments using the 60 keV transition in /sup 237/Np to study questions of delocalization of 5f electrons.

  17. Extended X-ray Absorption Fine Spectrometry for Np(Ⅴ) Adsorption to γ-FeOOH/Water Interface

    Institute of Scientific and Technical Information of China (English)

    YANG; Chun-li; ZHANG; Sheng-dong; RAO; Lin-feng

    2013-01-01

    237Np(Ⅴ)is estimated to be the most hazardous radionuclide concerning its half-time(2.14×106year),radiotoxicity and environmental behavior.It has been reported that most of actinides can be sequestered by a variety of minerals,especially iron oxides as common components of rocks,soils and sediments.Np(Ⅴ)sorption at mineral-water interfaces are of great importance in contaminant regulation

  18. Experimental study on neptunium migration under in situ geochemical conditions

    Science.gov (United States)

    Kumata, M.; Vandergraaf, T. T.

    1998-12-01

    Results are reported for migration experiments performed with Np under in situ geochemical conditions over a range of groundwater flow rates in columns of crushed rock in a specially designed facility at the 240-level of the Underground Research Laboratory (URL) near Pinawa, Manitoba, Canada. This laboratory is situated in an intrusive granitic rock formation, the Lac du Bonnet batholith. Highly altered granitic rock and groundwater were obtained from a major subhorizontal fracture zone at a depth of 250 m in the URL. The granite was wet-crushed and wet-sieved with groundwater from this fracture zone. The 180-850-μm size fraction was selected and packed in 20-cm long, 2.54-cm in diameter Teflon™-lined stainless steel columns. Approximately 30-ml vols of groundwater containing 3HHO and 237Np were injected into the columns at flow rates of 0.3, 1, and 3 ml/h, followed by elution with groundwater, obtained from the subhorizontal fracture, at the same flow rates, for a period of 95 days. Elution profiles for 3HHO were obtained, but no 237Np was detected in the eluted groundwater. After terminating the migration experiments, the columns were frozen, the column material was removed and cut into twenty 1-cm thick sections and each section was analyzed by gamma spectrometry. Profiles of 237Np were obtained for the three columns. A one-dimensional transport model was fitted to the 3HHO breakthrough curves to obtain flow parameters for this experiment. These flow parameters were in turn applied to the 237Np concentration profiles in the columns to produce sorption and dispersion coefficients for Np. The results show a strong dependence of retardation factors ( Rf) on flow rate. The decrease in the retarded velocity of the neptunium ( Vn) varied over one order of magnitude under the geochemical conditions for these experiments.

  19. Analysis of the evaluated data discrepancies for minor actinides and development of improved evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Ignatyuk, A. [Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1997-03-01

    The work is directed on a compilation of experimental and evaluated data available for neutron induced reaction cross sections on {sup 237}Np, {sup 241}Am, {sup 242m}Am and {sup 243}Am isotopes, on the analysis of the old data and renormalizations connected with changes of standards and on the comparison of experimental data with theoretical calculation. Main results of the analysis performed by now are presented in this report. (J.P.N.)

  20. Average resonance parameters evaluation for actinides

    Energy Technology Data Exchange (ETDEWEB)

    Porodzinskij, Yu.V.; Sukhovitskij, E.Sh. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    New evaluated <{Gamma}{sub n}{sup 0}> and values for {sup 238}U, {sup 237}Np, {sup 243}Cm, {sup 245}Cm, {sup 246}Cm and {sup 241}Am nuclei in the resolved resonance region are presented. The applied method based on the idea that experimental resonance missing results in correlated changes of reduced neutron widths and level spacings distributions is discussed. (author)

  1. The Study on the Migration of Radionuclides in the Shallow Land

    Energy Technology Data Exchange (ETDEWEB)

    Li, S.; Wang, Z.; Li, Z.; Zhao Y.; Guo, Z.; Guo, L.; Shi, Y.; Ogawa, H.; Maeda, T.; Matsumoto, J.; Mukai, M.; Tanaka, T.

    2002-02-25

    >From 1995 through 2001 a cooperative study project on the migration of radionuclides in shallow land was carried out by CIRP and JAERI, which covers field test, laboratory simulation test, other laboratory studies and related model development. The radionuclides studied involve 90Sr, 237Np, 238Pu. For comparison the nonradioactive elements Sr, Nd and Ce were also studied. The field test was performed both in aerated zone and aquifer zone of loess. In the aerated zone the nuclide migration in engineering materials were also studied. The study in the aerated zone was carried out in 9 pits with the size of 2m x 2m under natural conditions or artificial sprinkling conditions. The study in the aquifer was carried out in a new built Underground Research Facility with the area of 142m2. The test results show that the order of adsorption activity of the nuclide on the loess is 238Pu > 237Np > 90Sr and Nd, Ce > Sr. During the 3 years period of test the migration of 238Pu and Nd, Ce was not observable in both aerated zone and aquifer zone, the nuclide of 237Np migrated a small distance, and the nuclide of 90Sr had a relative large migration. The migration of the nuclides in engineering materials was not detected, which include cement, degraded cement, cement mortar, Chinese bentonite and Japanese bentonite.

  2. Thorium distributions in high- and low-dust regions and the significance for iron supply

    Science.gov (United States)

    Hayes, Christopher T.; Rosen, Jeffrey; McGee, David; Boyle, Edward A.

    2017-02-01

    Thorium and uranium isotopes (232Th, 230Th, 238U, and 234U) were investigated to refine their use for estimating mineral dust deposition and Fe delivery to the ocean. U concentrations and isotope ratios were consistent with conservative behavior and can safely be described using published U-salinity relationships and global average seawater isotopic composition. Near Barbados, waters affected by the Amazon outflow contained elevated 232Th. This signals one region where the thorium-dust method is inaccurate because of a confounding continental input. Dissolved 232Th fluxes in this region suggest that Amazonian Fe supply to the adjacent open ocean is much larger than local atmospheric deposition. The colloidal content of dissolved Th south of Bermuda was found to be quite small (2-6%), similar to that found north of Hawaii, despite the order of magnitude higher dust deposition in the Atlantic. This finding supports the assumption that dissolved 232Th and 230Th are scavenged at the same rate despite their different sources and also sheds light on the increase of dissolved 232Th fluxes with integrated depth. Outside the region influenced by Amazon River waters, dissolved 232Th fluxes are compared with Bermudan aerosol Fe deposition to estimate that fractional Th solubility is around 20% in this region. Finally, new dissolved and soluble Fe, Mn, and Cr data from the subtropical North Pacific support the idea that Fe concentrations in the remote ocean are highly buffered, whereas 232Th has a larger dynamic range between high- and low-dust regions.

  3. Decorporation and therapeutic efficacy of liposomal-DTPA against thorium-induced toxicity in the Wistar rat.

    Science.gov (United States)

    Kumar, Amit; Sharma, Pragya; Ali, Manjoor; Pandey, Badri Narain; Mishra, Kaushala Prasad

    2012-03-01

    This study examined the effect of liposomal encapsulation of (99m)Tc-labeled diethylenetriaminepentaacetic acid (metastable technetium labeled DTPA) on its organ distribution and therapeutic effect of optimized neutral liposomal-DTPA against thorium ((232)Th)-induced liver toxicity and its accumulation in rat animal model. (99m)Tc-DTPA was encapsulated in neutral (dipalmitoylphosphatidylcholine:cholesterol) and positively (dipalmitoylphosphatidylcholine:cholesterol:stearylamine) charged liposomes using thin film hydration method. Comparative efficacy of liposomal and free DTPA (11.2 mg/kg) was examined in terms of its effect on (232)Th accumulation and subsequent toxicity in the liver and blood of rat administered with (232)Th-nitrate (600 μg/kg). Organ distribution of free or liposomal (99m)Tc-DTPA was determined by solid scintillation counting and (232)Th accumulation by Inductively Coupled Plasma-Atomic Emission Spectroscopy. Neutral liposomes encapsulated with (99m)Tc-DTPA showed more uptake in liver, spleen and blood than with positively charged liposomal- and free- (99m)Tc-DTPA. Administration of (232)Th-nitrate to rat significantly increased the levels of liver toxicity markers and of oxidative injury, which were found to be restored more significantly by neutral liposomal-DTPA than free-DTPA. The accumulation of (232)Th in liver and blood of contaminated mice was found to be decreased more significantly by neutral liposomal-DTPA than by free-DTPA. Decorporation and consequent mitigation of (232)Th induced toxicity may be significantly improved by liposomal encapsulation of DTPA, a chelating agent.

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

    Science.gov (United States)

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

    2012-12-01

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    CERN Document Server

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

    2000-01-01

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

  7. Natural activity concentrations in bottled drinking water and consequent doses.

    Science.gov (United States)

    Kabadayi, Önder; Gümüs, Hasan

    2012-07-01

    The radioactivity concentrations of nuclides (238)U, (232)Th and (40)K in bottled drinking water from six different manufacturers from Turkey were measured using high-resolution gamma-ray spectrometry. The measurement was done using a coaxial high-purity germanium detector system coupled to Ortec-Dspect jr digital MCA system. The average measured activity concentrations of the nuclides (238)U, (232)Th and (40)K are found to be 0.781, 1.05 and 2.19 Bq l(-1), respectively. The measured activity concentrations have been compared with similar studies from different locations. The annual effective doses for ingestion of radionuclides in the water are found to be 0.0246 mSv for (238)U and 0.169 mSv for (232)Th.

  8. Direct gamma-ray measurement of different radionuclides in the surface water of Suez Canal; Mesure directe du rayonnement gamma emis par divers radionucleides dans les eaux de surface du canal de Suez

    Energy Technology Data Exchange (ETDEWEB)

    Lasheen, Y.F.; El-Zakla, T.; Seliman, A.F.; Abdel-Rassoul, A.A. [Hot Labs. Center, Atomic Energy Authority, Cairo (Egypt)

    2008-04-15

    The radioactivity levels of naturally-occurring {sup 238}U, {sup 232}Th, {sup 226}Ra and {sup 40}K and anthropogenic {sup 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 {sup 137}Cs radioactivity levels in surface water from the Suez Canal with those of other sea waters is presented. The radioactivity levels of {sup 238}U, {sup 232}Th, {sup 226}Ra and {sup 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 {sup 238}U, {sup 232}Th and {sup 226}Ra is discussed. (authors)

  9. Correlation of radon and thoron concentrations with natural radioactivity of soil in Zonguldak, Turkey

    Science.gov (United States)

    Koray, Abdullah; Akkaya, Gizem; Kahraman, Ayşegül

    2017-02-01

    Radon and thoron gases are produced by the decay of the radioactive elements those are radium and thorium in the soil. In this study, the correlations between soil radon and thoron concentration with their parent nuclide (226Ra and 232Th) concentrations in collected soil samples from the same locations were evaluated. The result of the measurement shows that the distribution of radon and thoron in soil showed the same tendency as 226Ra and 232Th distribution. It was found a weak correlation between the radon and the 226Ra concentration (R =0.57), and between the thoron and the 232Th concentration (R=0.64). No strong correlation was observed between soil-gas radon and thoron concentration (R = 0.29).

  10. Monte Carlo simulation of indoor external exposure due to gamma-emitting radionuclides in building materials

    Science.gov (United States)

    Deng, Jun; Cao, Lei; Su, Xu

    2014-10-01

    The use of building materials containing naturally occurring radionuclides, such as 40K, 238U, 232Th and their progeny, could lead to external exposures to the residents of such buildings. In this paper, a set of models are constructed to calculate the specific effective dose rates (the effective dose rate per Bq/kg of 40K, the 238U series, and the 232Th series) imposed on residents by building materials with the MCNPX code. The effect of chemical composition, position concerned in the room and thickness as well as density of material is analyzed. In order to facilitate more precise assessment of indoor external dose due to gamma-emitting radionuclides in building materials, three regressive expressions are proposed and validated by measured data to calculate specific effective rates for 40K. the 238U series and the 232Th series, respectively.

  11. Radionuclide concentration in cabbage samples due to gamma radiation in Samsun, Turkey

    Science.gov (United States)

    Altıkulaç, Aydan; Gümüş, Hasan

    2016-11-01

    Establishing of radioactivity planes in foodstuff has emphasis because it allows the evaluation of population exposure to radiation by take nourishment. In this paper, the activity concentrations of 226Ra, 232Th, 40K and 137Cs were determined in cabbage samples collected from Samsun city of Turkey using a gamma ray spectrometry method with a HPGe detector. The mean concentration value of 226Ra, 232Th, 40K and 137Cs in cabbage samples were 1.11±0.03 Bqkg-1, 1.44±0.04 Bqkg-1, 743.75±21.21 Bqkg-1 and 0.18±0.003 Bqkg-1, respectively. The calculated total annual effective dose received from 226Ra, 232Th, 40K and 137Cs due to cabbage samples by population of Samsun province was quite lower than the World average value as suggested by UNSCEAR.

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

    Science.gov (United States)

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

    2016-03-01

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

  13. 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...

  14. Natural gamma radioactivity and of {sup 137} Cs in soil of the Chimaltitan municipality, Jalisco, Mexico; Radiactividad gamma natural y del {sup 137} Cs en suelo del Municipio de Chimaltitan, Jalisco, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garay, A.; Mireles, F.; Quirino, L.L.; Davila, J.I.; Rios, C.; Lugo, J.F.; Soriano, J.M.; Angoli, A. [UAEN-Universidad Autonoma de Zacatecas, Cipres 10, Frac. La Penuela, 98000 Zacatecas (Mexico)]. e-mail: albinogaray@hotmail.com.mx

    2003-07-01

    With the purpose of determining the activity due to the natural presence of the {sup 226} Ra, {sup 232} Th, {sup 40} K and {sup 137} Cs in soil samples, of the municipality of Chimaltitan Jalisco. A set of these samples was measured in a gamma ray spectrometric system based on a High-purity Germanium detector. It is well-known that approximately 87% of the dose of the received radiation by the population is due to sources of natural radiation and 13% of the anthropogenic radiation. The gamma radiation comes mainly from the {sup 40} K and of those radionuclides of the series of radioactive decay of {sup 238} U and {sup 232} Th that its find dispersed thoroughly in the terrestrial crust. In this work its were analyzed twenty-two soil samples. It is enlarged the activity characterization for the radioisotopes of {sup 226} Ra {sup 232} Th, {sup 40} K and {sup 137} Cs. (Author)

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

    Science.gov (United States)

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

    2010-11-01

    The aim of this case study was to estimate the bioaccessibility of uranium ((238)U) and thorium ((232)Th) from a healing earth by analysing the solubility of these radionuclides in synthetic gastric and intestinal fluids. An easy applicable in vitro test system was used to investigate the fractional mobilization of the soil contaminants being potentially available for absorption under human in vivo conditions. These findings provided the basis for a prospective dose assessment. The solubility experiments were performed using two different in vitro digestion methods. The concentrations of (238)U and (232)Th in the solutions extracted from the soil were measured by inductively coupled plasma mass spectrometry (ICP-MS). The dissolved fractions in the synthetic gastrointestinal fluid ranged in average from 10.3% to 13.8% for (238)U and from 0.3% to 1.6% for (232)Th, respectively, depending on the digestion method. Subsequently, the committed effective doses from intake of (238)U and (232)Th after ingestion of the healing earth during 1 year were evaluated for adult persons. Thereby ingestion dose coefficients calculated as a function of bioaccessibility were used. The dose assessments ranged between 4.3 × 10(-7)-1.9 × 10(-6) Sv y(-1) for (238)U and 5.6 × 10(-7)-3.3 × 10(-6) Sv y(-1) for (232)Th, respectively. On the basis of the assumptions and estimations made, the present work indicates a relatively low radiation risk due to (238)U and (232)Th after internal exposure of the healing earth. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Natural radioactivity in sand beaches of Guarapari, Espirito Santo state, Brazil: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, Danilo C.; Pereira, Claubia; Oliveira, Arno H.; Santos, Talita O.; Reis, Patricia L., E-mail: danilo@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Dept. de Engenharia Nuclear; Rocha, Zildete, E-mail: rochaz@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MH (Brazil)

    2011-07-01

    Using gamma ray spectrometry, the activity concentration of naturally occurring radionuclides {sup 226}Ra, {sup 232}Th, and {sup 40}K was determined in sand beaches samples from different areas in Guarapari, Espirito Santo state, from Brazil. The absorbed dose rates and annual effective dose were calculated and the results are compared with the internationally accepted values as well as others high background radiation areas (HBRAs).The activity concentration of the {sup 232}Th in Areia Preta as well as the absorbed dose rates and annual effective dose were higher than the others regions compared. The results show that Areia Preta in Guarapari has higher background found in beaches in world. (author)

  17. Variations in radioactivity of phosphate rocks from differnet sites in Central Eastern Desert of Upper Egypt

    Institute of Scientific and Technical Information of China (English)

    AMEl-Arabi; AMMYousef

    2002-01-01

    Natural radionuclides in the phosphate rock samples collected from Wadi Batur,Wadi Hegaza and Gabal Abu Had at Eastern Desert were determined using a high resolution γ-ray spectrometer.The experimental results concerning 226Ra,232Th and their daughters are presented.Analyses of the measured spectra show that 226Ra is distinguished with remarkable activities with average values ranging from 22.4 to 558Bq/kg,while 232Th activity concentration is in the range of 9.7 to 92.8Bq/kg.The results of the analyses were found to be in a good agreement with the data obtained by others.

  18. Variations in radioactivity of phosphate rocks from different sites in Central Eastern Desert of Upper Egypt

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Natural radionuclides in the phosphate rock samples collected from Wadi Batur, Wadi Hegaza and Gabal Abu Had at Eastern Desert were determinedusing a high resolution γ-ray spectrometer. The experimental results concerning 226Ra,232Th and their daughters are presented. Analyses of the measured spectra show that226Ra is distinguished with remarkable activities with average values ranging from 22.4to 558 Bq/kg, while 232Th activity concentration is in the range of 9.7 to 92.8 Bq/kg.The results of the analyses were found to be in a good agreement with the dataobtained by others.

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

    Science.gov (United States)

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

    2016-03-01

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

  20. Distribution of Np and Pu in Swedish lichen samples (Cladonia stellaris) contaminated by atmospheric fallout

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, Patric E-mail: patric.lindahl@radfys.lu.se; Roos, Per; Eriksson, Mats; Holm, Elis

    2004-07-01

    The activity concentrations of {sup 237}Np and the two Pu isotopes, {sup 239}Pu and {sup 240}Pu, were determined in lichen samples (Cladonia stellaris) contaminated by fallout from atmospheric nuclear test explosions and the Chernobyl accident. The samples were collected at 18 locations in Sweden, from north to south, between 1986 and 1988 and analysed with high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) and alpha spectrometry. Data on the activity ratios {sup 238}Pu/{sup 239+240}Pu and {sup 134}Cs/{sup 137}Cs measured previously were also included in this study for comparison. The {sup 237}Np activity concentration ranged from 0.08{+-}0.01 to 2.08{+-}0.17 mBq kg{sup -1}, depending on the location of the sampling site and time of collection. The {sup 239+240}Pu activity concentration ranged from 0.09{+-}0.01 to 4.09{+-}0.15 Bq kg{sup -1}, with the {sup 240}Pu/{sup 239}Pu atomic ratio ranging between 0.16{+-}0.01 and 0.44{+-}0.03, the higher ratios indicating a combination of weapons test fallout and Chernobyl fallout. The {sup 237}Np/{sup 239}Pu atomic ratios ranged between 0.06{+-}0.01 and 0.42{+-}0.04, the lower ratios indicating combination of weapons test fallout and Chernobyl fallout. At a well-defined sampling site at Lake Rogen (62.32 deg. N, 12.38 deg. E), additional lichen samples were collected between 1987 and 1998 to study the distribution of Np and Pu in different layers. The concentrations of the two elements follow each other quite well in the profile.

  1. Fission cross section calculations of actinides with EMPIRE code

    Energy Technology Data Exchange (ETDEWEB)

    Sin, M.; Oblozinsky, P.; Herman,M.; Capote,R.

    2010-04-30

    The cross sections of the neutron induced reactions on {sup 233,234,236}U, {sup 237}Np, {sup 238,242}Pu, {sup 241,243}Am, {sup 242,246}Cm carried out in the energy range 1 keV-20 MeV with EMPIRE code are presented, emphasizing the fission channel. Beside a consistent, accurate set of evaluations, the paper contains arguments supporting the choice of the reaction models and input parameters. A special attention is paid to the fission parameters and their uncertainties.

  2. TANGRA-Setup for the Investigation of Nuclear Fission induced by 14.1 MeV neutrons

    OpenAIRE

    RUSKOV I.; Kopatch, Y; BYSTRITSKY V.; Skoy, V.; SHVETSOV V.; Hambsch, Franz-Josef; Oberstedt, Stephan; CAPOTE NOY R.; Sedyshev, P.; GROZDANOV D.; IVANOV I. Zh.; ALEKSAKHIN V. Yu.; BOGOLUBOV E. P.; BARMAKOV Y.; Khabarov, S. V.

    2015-01-01

    The new experimental setup TANGRA (Tagged Neutrons & Gamma Rays), for the investigation of neutron induced nuclear reactions, e.g. (n,xn’), (n,xn’γ), (n,γ), (n,f), on a number of important isotopes for nuclear science and engineering (235,238U, 237Np, 239Pu, 244,245,248Cm) is under construction and being tested at the Frank Laboratory of Neutron Physics (FLNP) of the Joint Institute for Nuclear Research (JINR) in Dubna. The TANGRA setup consists of: a portable neutron generator ING-27, wit...

  3. Advances in fuel materials for the transmutation of actinides

    Energy Technology Data Exchange (ETDEWEB)

    Prunier, C.

    1994-12-31

    The physical feasibility of actinides, spent fuels and fission products burning in fission reactors is well understood. In fast reactors, this operation is more favourable. The homogeneous recycling mode has had a preliminary validation in Phenix (the Super fact experiment). For the heterogenous recycling mode, past experience for {sup 238} Pu production in thermal spectrum was obtained with Np O{sub 2}-Mg O targets. An irradiation experiment in Phenix blanket is foreseen with the same type of target. The {sup 237} Np problem seems to be most conveniently treated, even in the short term, by homogeneous recycling with Pu in fast reactors. (author). 15 figs., 4 tabs.

  4. Modelling of reaction cross sections and prompt neutron emission

    Directory of Open Access Journals (Sweden)

    Oberstedt S.

    2010-10-01

    Full Text Available Accurate nuclear data concerning reaction cross sections and the emission of prompt fission neutrons (i.e. multiplicity and spectra as well as other fission fragment data are of great importance for reactor physics design, especially for the new Generation IV nuclear energy systems. During the past years for several actinides (238U(n, f and 237Np(n, f both the reaction cross sections and prompt neutron multiplicities and spectra have been calculated within the frame of the EFNUDAT project.

  5. Reactivity worth measurements with Caliban and Silene experimental reactors

    Energy Technology Data Exchange (ETDEWEB)

    Casoli, P.; Authier, N. [CEA Valduc, 21 - Is-sur-Tille (France)

    2008-07-01

    Reactivity worth measurements of material samples put in the central cavities of nuclear reactors allow to test cross section nuclear databases or to extract information about the critical masses of fissile elements. Such experiments have already been completed on the CALIBAN and SILENE experimental reactors operated by the Criticality and Neutronics Research Laboratory of Valduc (Cea, France), using the perturbation measurement technique. Feasibility studies have been performed to prepare future experiments on new materials (beryllium, copper, tantalum, {sup 237}Np) and results show that the obtained values for most materials are clearly above the measurement limits and then the perturbation technique can be used even with smaller size samples.

  6. Speciation of Long-Lived Radionuclides in the Environment

    DEFF Research Database (Denmark)

    Hou, Xiaolin

    , isotopes of Pu, and 237Np in seawater, fresh water, soil, sediment, vegetations, and concrete. The developed methods are used for the investigation of the chemical speciation of these radionuclides as well as their environmental behaviours, especially in Danish environment. In addition the speciation of Pu......This project started in November 2005 and ended in November 2008, the work and research approaches are summarized in this report. This project studied the speciation of radionuclides in environment. A number of speciation analytical methods are developed for determination of species of 129I, 99Tc...

  7. Leaching characteristics of actinides from simulated reactor waste glass

    Energy Technology Data Exchange (ETDEWEB)

    Weed, H.C.; Coles, D.G.; Bradley, D.J.; Mensing, R.W.; Schweiger, J.S.; Rego, J.H.

    1979-08-01

    Even without statistical analysis, some general trends can be seen in the results: leach rate increases with flow rate at high temperature, but is approximately independent of it at room temperature; agreement between the results from the one-pass method and those from the IAEA method are fair in the case of WIPP brine solution, and good in the case of the others; and the /sup 237/Np leach rate increases with temperature, but the /sup 239/Pu leach rate either decreases with temperature or does not change.

  8. Magnetic sublattices in Np{sub 2}Co{sub 17} and Np{sub 2}Ni{sub 17}

    Energy Technology Data Exchange (ETDEWEB)

    Colineau, E., E-mail: eric.colineau@ec.europa.eu; Hen, A. [Institute for Transuranium Elements (ITU), European Commission, Joint Research Centre (JRC) (Germany); Sanchez, J.-P. [CEA, INAC-SPSMS (France); Griveau, J.-C.; Magnani, N.; Eloirdi, R. [Institute for Transuranium Elements (ITU), European Commission, Joint Research Centre (JRC) (Germany); Halevy, I. [Ben Gurion University, Nuclear Engineering Department (Israel); Gaczyński, P. [Institute for Transuranium Elements (ITU), European Commission, Joint Research Centre (JRC) (Germany); Orion, I. [Ben Gurion University, Nuclear Engineering Department (Israel); Shick, A. B. [Institute of Physics, ASCR (Czech Republic); Caciuffo, R. [Institute for Transuranium Elements (ITU), European Commission, Joint Research Centre (JRC) (Germany)

    2016-12-15

    Rare-earth-based compounds R{sub 2}T{sub 17} (R=Rare earth; T=Transition metal) have been extensively studied and developed for applications as permanent magnets. The actinide-based analogues, however, are much less documented and we report here about the magnetic properties of Np{sub 2}Co{sub 17} and Np{sub 2}Ni{sub 17}, as inferred from {sup 237}Np Mössbauer spectroscopy, the best resonance in actinides, and specific heat.

  9. Photofissility of heavy nuclei at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Deppman, A.; Arruda Neto, J.D.T.; Likhachev, V.P. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Tavares, O.A.P.; Duarte, S.B.; Oliveira, E.C. de [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)

    2002-10-01

    We use the recently developed MCMC/MCEF (Multi Collisional Monte Carlo plus Monte Carlo for Evaporation-Fission calculations) model to calculate the photo fissility and the photofission cross section at intermediate energies for the {sup 243} Am and for {sup 209} Bi, and compare them to results obtained for other actinides and to available experimental data. As expected, the results for {sup 243} Am are close to those for {sup 237} Np. The fissility for pre actinide nuclei is nearly one order of magnitude lower than that for the actinides. Both fissility and photofission cross section for {sup 209} Bi are in good agreement with the experimental data. (author)

  10. The ultra-pure Ti for the low background experiments

    Science.gov (United States)

    Chepurnov, Alexander; Nisi, Stefano; di Vacri, Maria Laura; Suvorov, Yury

    2013-08-01

    The constant increase in mass of the cryostats, containment tanks, passive shielding and other mechanical elements of the modern low background detectors put more stringent requirements on their radiopurity levels. In general they have to be ˜1 mBq/kg of 238U/232Th or lower, which means that mass concentration should be manufactory line.

  11. Specific activities and radiological hazard assessment in beach sand samples in Songkhla province, Thailand after Fukushima Dai-Ichi nuclear power plant accident in Japan

    Science.gov (United States)

    Kessaratikoon, P.; Boonkrongcheep, R.; Choosiri, N.; Daoh, M.; Udomsomporn, S.

    2017-06-01

    According to the Fukushima Dai-Ichi Nuclear Power Plant Accident in Japan on March 11, 2011, specific activities of natural (40K, 226Ra and 232Th) and anthropogenic (137Cs) radionuclides in 210 beach sand samples which were collected from Maharat, Sai Kaew, Samila, Chalatat, Na Thab, Sakom and Soi Sawan beaches in Songkhla Province along the eastern coast of Thailand, have been studied and evaluated. The specific activity levels of 40K, 226Ra, 232Th and 137Cs in the area were found in the range 110.13 - 4574.12, 6.99 - 451.87, 3.75 - 665.76 and 0.58- 9.91 Bq/Kg, respectively. Furthermore, the median values of specific activities of 40K, 226Ra, 232Th and 137Cs were calculated and compared with other research data in Thailand as well as global measurements and evaluations. Moreover, four radiological hazard indices for the studied area were also assessed by using the median values of specific activities of 40K, 226Ra and 232Th.

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

    Science.gov (United States)

    Misdaq, M A; Outeqablit, K

    2010-12-01

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

  13. Breeding of 233U in the thorium-uranium fuel cycle in VVER reactors using heavy water

    Science.gov (United States)

    Marshalkin, V. E.; Povyshev, V. M.

    2015-12-01

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the 233U-232Th oxide fuel of water-moderated reactors with variable water composition (D2O, H2O) that ensures breeding of the 233U and 235U isotopes. The method is comparatively simple to implement.

  14. Determination of traces of uranium and thorium in titanium and copper used for the construction of the Russian Emission Detector 100 by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Poteshin, Sergey S; Sysoev, Alexey A; Lagunov, Sergey S; Sereda, Andrei; Sosnovtsev, Valery V; Bolozdynya, Alexander I; Efremenko, Yuriy B

    2015-01-01

    The Russian Emission Detector 100 (RED-100) under construction at the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) is designed to detect the presently undiscovered effect of coherent neutrino scattering. One of the factors limiting the sensitivity of the detector is the spontaneous decay of uranium and thorium in the detector materials. Radioactive impurities in detector materials at levels of parts per billion can significantly affect the sensitivity. Five random samples of titanium and one of copper from materials used in the construction of the detector were selected for assay. The concentration of (232)Th and (238)U were measured by inductively coupled plasma mass spectrometry (ICP- MS) in solid titanium using both: solutions in acids and direct sampling by laser ablation (LA-ICP-MS). The LA- ICP-MS method allowed us to determine (238)U and (232)Th at subnanogram per gram levels. This method is much faster than ICP-MS with liquid injection. The titanium samples studied have impurities in the range between 1 ng g(-1) and 21 ng g(-1) for (238)U and 3 ng g(-1) and 31 ng g(-1) for (232)Th. In copper we set upper limits of 0.4 ng g(-1) for (238)U and 1 ng g(-1)for (232)Th. The total activity of the cryostat constructed from materials studied was estimated to be 43 Bq.

  15. Radiometric fingerprinting of fluvial sediments in the Rhine-Meuse delta, the Netherlands – a feasibility test

    NARCIS (Netherlands)

    Hebinck, K.; Middelkoop, H.; van Diepen, N.M; van der Graaf, E.R.; de Meijer, R.J.

    2007-01-01

    The deposits of the Rhine and the Meuse in the Netherlands alternate in their delta in a complex way. This paper discusses a method to distinguish the deposits of the Rhine and the Meuse based on the differences in natural radioactivity of (40)K, (238)U and (232)Th, and the effect of the age of the

  16. Feasibility of Thorium Fuel Cycles in a Very High Temperature Pebble-Bed Hybrid System

    Directory of Open Access Journals (Sweden)

    L.P. Rodriguez

    2015-08-01

    Full Text Available Nuclear energy presents key challenges to be successful as a sustainable energy source. Currently, the viability of the use thorium-based fuel cycles in an innovative nuclear energy generation system is being investigated in order to solve these key challenges. In this work, the feasibility of three thorium-based fuel cycles (232Th-233U, 232Th-239Pu, and 232Th-U in a hybrid system formed by a Very High Temperature Pebble-Bed Reactor (VHTR and two Pebble-Bed Accelerator Driven Systems (ADSs was evaluated using parameters related to the neutronic behavior such as nuclear fuel breeding, minor actinide stockpile, the energetic contribution of each fissile isotope, and the radiotoxicity of the long lived wastes. These parameters were used to compare the fuel cycles using the well-known MCNPX ver. 2.6e computational code. The results obtained confirm that the 232Th-233U fuel cycle is the best cycle for minimizing the production of plutonium isotopes and minor actinides. Moreover, the inclusion of the second stage in the ADSs demonstrated the possibility of extending the burnup cycle duration and reducing the radiotoxicity of the discharged fuel from the VHTR.

  17. Natural thorium isotopes in marine sediment core off Labuan port

    Energy Technology Data Exchange (ETDEWEB)

    Hafidz, B. Y.; Asnor, A. S.; Terence, R. C.; Mohamed, C. A. R. [School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600, Bangi, Selangor (Malaysia)

    2014-02-12

    Sediment core was collected from Labuan port and analyzed to determine the radioactivity of thorium (Th) isotopes. The objectives of this study are to determine the possible sources of Th isotopes at Labuan port and estimates the sedimentation rate based on {sup 228}Th/{sup 232}Th model. The results suggest the {sup 230}Th and {sup 232}Th might be originated from terrestrial sedimentary rock while {sup 228}Th originated by authigenic origin. High ratio value of {sup 230}Th/{sup 232}Th detected at the top surface sediment indicates the increasing of {sup 230}Th at the recent years which might be contributed from the anthropogenic sources. The sedimentation rate of core sediment from Labuan Port was successfully estimated by using {sup 228}Th/{sup 232}Th model. The result show high sedimentation rate with 4.67 cm/year indicates rapid deposition occurred at this study area due to the high physical activity at the Labuan port. By assume the constant sedimentation rate at this area; we estimated the age of 142 cm core sediment obtained from Labuan port is 32 years started from 1981 to 2012. This chronology will be used in forthcoming research to investigate the historical profile of anthropogenic activities affecting the Labuan port.

  18. Natural thorium isotopes in marine sediment core off Labuan port

    Science.gov (United States)

    Hafidz, B. Y.; Asnor, A. S.; Terence, R. C.; Mohamed, C. A. R.

    2014-02-01

    Sediment core was collected from Labuan port and analyzed to determine the radioactivity of thorium (Th) isotopes. The objectives of this study are to determine the possible sources of Th isotopes at Labuan port and estimates the sedimentation rate based on 228Th/232Th model. The results suggest the 230Th and 232Th might be originated from terrestrial sedimentary rock while 228Th originated by authigenic origin. High ratio value of 230Th/232Th detected at the top surface sediment indicates the increasing of 230Th at the recent years which might be contributed from the anthropogenic sources. The sedimentation rate of core sediment from Labuan Port was successfully estimated by using 228Th/232Th model. The result show high sedimentation rate with 4.67 cm/year indicates rapid deposition occurred at this study area due to the high physical activity at the Labuan port. By assume the constant sedimentation rate at this area; we estimated the age of 142 cm core sediment obtained from Labuan port is 32 years started from 1981 to 2012. This chronology will be used in forthcoming research to investigate the historical profile of anthropogenic activities affecting the Labuan port.

  19. Radiometric fingerprinting of fluvial sediments in the Rhine-Meuse delta, the Netherlands – a feasibility test

    NARCIS (Netherlands)

    Hebinck, K.; Middelkoop, H.; Diepen, N. van; Graaf, E.R. van der; Meijer, R.J. de

    2007-01-01

    The deposits of the Rhine and the Meuse in the Netherlands alternate in their delta in a complex way. This paper discusses a method todistinguish the deposits of the Rhine and the Meuse based on the differences in natural radioactivity of 40K, 238U and 232Th, and the effect ofthe age of the deposits

  20. Content of Transuranium Nuclide in Process of Irradiating Thorium

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Currently, sufficient nuclear fuel supply is most important problem with the nuclear power grow rapidly, so the use of thorium fuel is being put on the agenda. The applicability of thorium as a power reactor is based on a (n, γ) reaction on 232Th. The consequent nucleus, 233Th,

  1. The Calculation of 233U and 232U in Irradiation Process of Thorium

    Institute of Scientific and Technical Information of China (English)

    MA; Peng; MAO; Guo-shu

    2012-01-01

    <正>Currently,sufficient nuclear fuel supply is the most important problem with the nuclear power growing rapidly, so the use of thorium fuel is being put on the agenda. The applicability of thorium as a power reactor fuel is based on a (n, γ) reaction of 232Th. The resulting nuclide, 233Th, is unstable to form

  2. Growth rate and chemical composition of a manganese nodule from the EEZ of Seychelles

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.; Borole, D.V.

    mhe ferro-manganese nodule collected in EEZ of Seychelles yields a growth rate of 1.5 mm/10 6Y 230Th (ex)/ and 230Th (ex)/ 232Th activity ratio methods indicating very slow growth of ferro-manganese nodules. The Mn/Fe and U/Th ratios suggest...

  3. Radionuclide concentrations in mussels collected from the southern coast of Bangladesh

    Energy Technology Data Exchange (ETDEWEB)

    Alam, M.N.; Chowdhury, M.I.; Kamal, M.; Ghose, S. E-mail: rtl@globalctg.net; Matin, A.K.M.A.; Ferdousi, G.S.M

    2000-01-01

    Concentrations of {sup 226}Ra, {sup 232}Th, {sup 238}U, {sup 40}K and {sup 137}Cs were determined in whole soft tissues (WST) and shells of groups of different size of marine mussel Perna viridis L. and estuarine mussel Modiolus striatulus H. and water samples which were collected from the southern coast of Bangladesh. Correlation analysis showed that the concentrations of radionuclides vary with mussel size. A positive correlation existed for {sup 238}U and {sup 40}K and a negative one for {sup 232}Th between the radionuclide concentration and mussel size; {sup 232}Th concentrations in WST and shells of the mussels showed an inverse relationship with those of {sup 238}U and {sup 40}K, while {sup 238}U showed positive correlation with {sup 40}K. The concentration factors (CF) for {sup 226}Ra, {sup 232}Th and {sup 238}U in both P. viridis and M. striatulus were higher than those for {sup 40}K. The contents of {sup 137}Cs in both mussels were below the detection limit.

  4. Gamma radiation measurement in select sand samples from Camburi beach - Vitoria, Espirito Santo, Brazil: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Livia F.; Pecequilo, Brigitte R.S.; Aquino, Reginaldo R., E-mail: lfbarros@ipen.b, E-mail: brigitte@ipen.b, E-mail: raquino@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The variation of natural radioactivity along the surface of the beach sands of Camburi, located in Vitoria, capital of Espirito Santo, southeastern Brazil, was determined from the contents of {sup 226}Ra, {sup 232}Th and {sup 40}K. Eleven collecting points was selected along all the 6 km extension of the Camburi beach. Sand samples collected from all established points on January 2011 were dried and sealed in standard 100 mL polyethylene flasks and measured by high resolution gamma spectrometry after a 4 weeks ingrowth period, in order to allow the secular equilibrium in the {sup 238}U and {sup 232}Th series. The {sup 226}Ra concentration was determined from the weighted average concentrations of {sup 214}Pb and {sup 214}Bi. The {sup 232}Th concentration was determined from the weighted average concentrations of {sup 228}Ac, {sup 212}Pb and {sup 212}Bi and the {sup 40}K from its single gamma transition. Preliminary results show activity concentrations varying from 5 Bq.kg{sup -1} to {sup 222} Bq.kg{sup -1} for {sup 226}Ra and from 14 Bq.kg{sup -1} to 1074 Bq.kg{sup -'}1 for {sup 232}Th, both with the highest values for Camburi South and Central. For {sup 40}K, the activity concentrations ranged from 14 Bq.kg{sup -1} to 179 Bq.kg{sup -1} and the highest values were obtained for Camburi South. (author)

  5. Natural radioactivity and chemical concentrations in Egyptian groundwater.

    Science.gov (United States)

    Amin, Rafat M; Khalil, F A; El Fayoumi, M A K

    2011-02-01

    Measurements of natural radioactivity in drinking water have been performed in many parts of the world, mostly for assessment of the doses and risk resulting from consuming water. A study of the radionuclide and chemical components in groundwater from Beni Suef Governate, Egypt has been carried out. Fifty water samples were analyzed by gamma ray spectroscopy to determine the 226Ra, 232Th, and 40K concentrations; major elements, pH, alkalinity, and conductivity were also measured. The specific activity values ranged from 0.008 to 0.040 Bq/l for 226Ra, from 0.003 to 0.019 Bq/l for 232Th, and from 0.025 to 0.344 Bq/l for 40K. The annual ingestions of these radionuclides, using local consumption rates (average over the whole population) of 1.5 l day(-1), were estimated to be 8.59, 4.86, and 83.47 Bq year(-1) for 226Ra, 232Th, and 40K, respectively. The estimated values and weighted means of these radionuclides compare well with the world average. The estimated effective doses from drinking water were found to be 2.4 μSv year(-1) (226Ra), 1.1 μSv year(-1) (232Th), and 0.51 μSv year(-1) (40K). Contribution of these radionuclides to the committed effective dose from 1 year consumption of drinking water is estimated to be only 4%.

  6. Determination of radionuclide concentration of landfill at Eliozu, Port ...

    African Journals Online (AJOL)

    A survey of the radionuclide concentration from landfill around Eliozu in Port- Harcourt ... 232Th, 238U and 40K. 10 soil and 10 water samples collected from the respective ... This value is lesser than the world-averaged of 55 nGy.h−1for soil.

  7. THERMOLUMINESCENT DOSIMETRY

    African Journals Online (AJOL)

    2005-10-20

    Oct 20, 2005 ... abo area of the city has the least radiation dose rate while Obantoku area has the upper limit. aking this as ... 'n Abeokuta. eywords: Environmental radiation, thermoluminescent dosimetry, Abeokuta, outdoor ... Both 238U and 232Th have long decay series with ... effects of radiation exposure (Hanson and.

  8. THERMOLUMINESCENT DOSIMETRY

    African Journals Online (AJOL)

    2005-10-20

    Oct 20, 2005 ... abo area of the city has the least radiation dose rate while Obantoku area has the upper limit. aking this as ... “n Abeokuta. eywords: Environmental radiation, thermoluminescent dosimetry, Abeokuta, outdoor ... Both 238U and 232Th have long decay series with ... effects of radiation exposure (Hanson and.

  9. Delayed reflow of an ischemic infarct after spontaneous thrombolysis studied by CBF tomography using SPECT and Tc-99m HMPAO

    DEFF Research Database (Denmark)

    Companioni, J M; Lassen, N A; Tfelt-Hansen, P

    1991-01-01

    A patient with a large ischemic infarct in the left middle cerebral artery territory was studied six times in the acute/subacute phase by cerebral blood flow (CBF) tomography using Tc-99m-HMPAO. The SPECT instrument used was a brain dedicated highly sensitive four-camera system (TOMOMATIC 232) th...

  10. Breeding of {sup 233}U in the thorium–uranium fuel cycle in VVER reactors using heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Marshalkin, V. E., E-mail: marshalkin@vniief.ru; Povyshev, V. M. [Russian Federal Nuclear Center All-Russian Research Institute of Experimental Physics (VNIIEF) (Russian Federation)

    2015-12-15

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the {sup 233}U–{sup 232}Th oxide fuel of water-moderated reactors with variable water composition (D{sub 2}O, H{sub 2}O) that ensures breeding of the {sup 233}U and {sup 235}U isotopes. The method is comparatively simple to implement.

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

    Science.gov (United States)

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

    2015-12-10

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

  12. 77 FR 29697 - Honeywell Metropolis Works; Grant of Exemption for Honeywell Metropolis Works License

    Science.gov (United States)

    2012-05-18

    ... and ALI determinations (Ref. 4). Consistent with the ICRP 68 methodology, Honeywell also requested... isotopes of thorium, uranium, and some of the transuranic radionuclides. For example, for inhalation of insoluble thorium-232 (\\232\\Th), the CEDE per unit intake calculated using the revised ICRP lung model is a...

  13. {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.

  14. The absorption and scavenging ability of a bacillus on the of heavy ...

    African Journals Online (AJOL)

    微软用户

    2014-09-05

    Sep 5, 2014 ... radioactive materials (NORMs) from 238U and 232Th and their respective ... radionuclides in the end products and wastes of the phosphate industry. .... MATERIALS AND METHODS ... (Jamok, 2014), and stored at room temperature for a period of 5 .... phosphate rock samples is above the proposed safety.

  15. Dependency of renal thorium and uranium excretion from age and gender in non-exposed persons; Abhaengigkeit der renalen Thorium- und Uranausscheidung von Geschlecht und Alter bei nicht-exponierten Personen

    Energy Technology Data Exchange (ETDEWEB)

    Werner, E.; Roth, P.; Wendler, I.; Schramel, P. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Neuherberg (Germany)

    1998-12-31

    For the assessment of an occupational incorporation of thorium or uranium it is essential to know which portion of the measured activity is caused by natural sources. In the present study the daily urinary excretion of {sup 232}Th and {sup 238}U was measured in 76 healthy volunteers. None of them had a previous history of occupational exposure to thorium or uranium. The data show no difference in the excretion between male and female subjects. Whereas in adolescents only little excretion of {sup 232}Th and {sup 238}U is found, a significantly increasing variation of thorium and uranium in urine is observed with progressing age. From the data obtained an age-related upper limit of {sup 232}Th and {sup 238}U urinary excretion can be derived, which may be useful for the interpretation of a measured value due to the occupational exposure. (orig.) [Deutsch] Fuer die Beurteilung einer beruflich bedingten Inkorporation von Thorium oder Uran ist es wichtig zu wissen, welcher Artikel am gemessenen Wert auf natuerliche Quellen zurueckzufuehren ist. In der vorliegenden Studie wurde die taegliche Ausscheidung von{sup 232}Th und {sup 238}U im Urin bei 76 gesunden Personen im Alter von 7 bis 84 Jahren mit der ICP-MS gemessen. Keine dieser Personen hatte vorher beruflichen Umgang mit Thorium oder Uran gehabt. Die Daten zeigen keinen Unterschied zwischen Frauen und Maennern. Waehrend bei Jugendlichen nur geringe Ausscheidungswerte beobachtet werden, tritt mit zunehmendem Lebensalter eine erhebliche Vergroesserung des Variationsbereichs ein. Aus den erhobenen Daten ergibt sich eine altersbezogene Obergrenze fuer die {sup 232}Th- und {sup 238}U-Ausscheidung im Urin, die fuer die Interpretation eines Messwertes bei beruflicher Exposition herangezogen werden kann. (orig.)

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    SCEPAN S. MILJANIC

    2007-06-01

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

  18. Thorium isotopes in colloidal fraction of water from San Marcos Dam, Chihuahua, Mexico

    Science.gov (United States)

    Cabral-Lares, M.; Melgoza, A.; Montero-Cabrera, M. E.; Renteria-Villalobos, M.

    2013-07-01

    The main interest of this stiidy is to assess the contents and distribution of Th-series isotopes in colloidal fraction of surface water from San Marcos dam, because the suspended particulate matter serves as transport medium for several pollutants. The aim of this work was to assess the distribution of thorium isotopes (232Th and 230Th) contained in suspended matter. Samples were taken from three surface points along the San Marcos dam: water input, midpoint, and near to dam wall. In this last point, a depth sampling was also carried out. Here, three depth points were taken at 0.4, 8 and 15 meters. To evaluate the thorium behavior in surface water, from every water sample the colloidal fraction was separated, between 1 and 0.1 μm. Thorium isotopes concentraron in samples were obtained by alpha spectrometry. Activity concentrations obtained of 232Th and 230Th in surface points ranged from 0.3 to 0.5 Bq ṡ L-1, whereas in depth points ranged from 0.4 to 3.2 Bq ṡ L-1, respectively. The results show that 230Th is in higher concentration than 232Th in colloidal fraction. This can be attributed to a preference of these colloids to adsorb uranium. Thus, the activity ratio 230Th/232Th in colloidal fraction showed values from 2.3 to 10.2. In surface points along the dam, 230Th activity concentration decreases while 232Th concentration remains constant. On the other hand, activity concentrations of both isotopes showed a pointed out enhancement with depth. The results have shown a possible lixiviation of uranium from geological substrate into the surface water and an important fractionation of thorium isotopes, which suggest that thorium is non-homogeneously distributed along San Marcos dam.

  19. Partitioning of protactinium, uranium, thorium and other trace elements between columbite and hydrous silicate melt

    Science.gov (United States)

    Huang, F.; Schmidt, M. W.; Günther, D.; Eikenberg, J.

    2009-12-01

    U-series disequilibria are a unique powerful tool to constrain the time-scales and processes of magmatism in mid-ocean ridge, intra-plate, and convergent margin settings. 235U-231Pa is one of the important parent-daughter pairs (231Pa half life = 33 kyr) because protactinium is normally much more incompatible than U during magmatism and thus the ubiquitously observed 231Pa excess in young igneous rocks most likely reflects melting processes. However, because of the extreme incompatibility of protactinium in most silicate minerals (mineral/meltDPa determined at the permissible Pa doping level of 10 ppm (bulk). Experiments were run in a piston cylinder apparatus at 0.5 GPa and 1115 oC using Pt double capsules with NNO or FMQ as external fO2 buffers. The starting material is a hydrous per-aluminous granitic composition, doped with Pa solution in the Paul Scherrer Institute and also contains other trace elements including U, Th, REE, Zr, Hf, W, Mo, Ti, V, Ge, P, and Sn. Experiments employing an oscillating rather than constant temperature have produced columbite crystals up to 30 μm and large areas of crystal-free water-saturated silicate melts. Columbite/silicate melt partition coefficients of non-radioactive trace elements are presently measured by LA-ICP-MS, and Pa will be added as a next stage. The result will give the oxidation state of Pa at oxygen fugacities of the mantle and crust, and have important implications for the partitioning of Pa between silicate minerals and melt and on our understanding of 231Pa-235U disequilibrium in natural magmatic systems.

  20. U-series disequilibria of trachyandesites from minor volcanic centers in the Central Andes

    Science.gov (United States)

    Huang, Fang; Sørensen, Erik V.; Holm, Paul M.; Zhang, Zhao-Feng; Lundstrom, Craig C.

    2017-10-01

    Young trachyandesite lavas from minor volcanic centers in the Central Andes record the magma differentiation processes at the base of the lower continental crust. Here we report U-series disequilibrium data for the historical lavas from the Andagua Valley in Southern Peru to define the time-scale and processes of magmatism from melting in the mantle wedge to differentiation in the crust. The Andagua lavas show (230Th)/(238U), (231Pa)/(235U), and (226Ra)/(230Th) above unity except for one more evolved lava with 230Th depletion likely owing to fractional crystallization of accessory minerals. The 226Ra excess indicates that the time elapsed since magma emplacement and differentiation in the deep crust is within 8000 years. Based on the correlations of U-series disequilibria with SiO2 content and ratios of incompatible elements, we argue that the Andagua lavas were produced by mixing of fresh mantle-derived magma with felsic melt of earlier emplaced basalts in the deep crust. Because of the lack of sediment in the Chile-Peru trench, there is no direct link of recycled slabs with 230Th and 231Pa excesses in the Andagua lavas. Instead, 230Th and 231Pa excesses are better explained by in-growth melting in the upper mantle followed by magma differentiation in the crust. Such processes also produced the 226Ra excess and the positive correlations among (226Ra)/(230Th), Sr/Th, and Ba/Th in the Andagua lavas. The time-scale of mantle wedge melting should be close to the half-life of 231Pa (ca. 33 ka), while it takes less than a few thousand years for magma differentiation to form intermediate volcanic rocks at a convergent margin.

  1. High-resolution fission cross section of 231Pa. [0. 4 eV to 12 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Plattard, S.; Auchampaugh, G. F.; Hill, N. W.; de Saussure, G.; Perez, R. B.; Harvey, J. A.

    1979-01-01

    The /sup 231/Pa fission cross section was measured with high resolution at OREA from 0.1 to 12 MeV and between 0.4 eV and 10 keV. The data show evidence for fractionated vibrational structures in the threshold region of the fission cross section, and narrow fission resonances above 0.4 eV with an average fission width < GAMMA/sub f/ > = 8 ..mu..eV. 3 figures, 3 tables.

  2. Study for 228Th reduction in thermal reactor with Th-U fuel cycls

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    By using computercode WIMS/CENDL, the effects of some parameters, core configuration such as fuel element structure, neutron flux and burn-up, are discussed in thispaper.It is shown that high neutron flux, small fuel rod diameter,large volume ratio of coolant to fuel, seed-blank heterogeneous corearrangement and 231Pa chemical separation are necessary for reducing 228Th production in reactor.

  3. Mantle Plume Upwelling Rates: Evidence from U-Series in Young Ocean Island Basalts

    Science.gov (United States)

    Bourdon, B.; Turner, S. P.; Stracke, A.; Saal, A. E.

    2004-12-01

    U-series disequilibria measured in recent lavas at intraplate volcanoes provide a powerful probe to examine the validity of the plume model. U-Th and U-Pa fractionation produced during melting is a function of the melting rate. In turn, this parameter should scale with mantle upwelling velocities. Simply stated, a larger melting rate (larger mantle upwelling velocity) yields smaller Th and Pa excess relative to their parent nuclides. A number of observations supports this approach: (1) there is a negative correlation between 230Th excess and buoyancy fluxes (2) based on new measurements of 231Pa in the Azores, Iceland and the Galapagos and literature data, we show here that there is also a well defined correlation between 231Pa excess and buoyancy flux (3) For Hawaii, Iceland and the Azores, 230Th excess (or 231Pa excess) increases as a function of the distance from the centre of the `hotspot'. These observations suggests that `hotspot' buoyancy fluxes are associated with a greater melt production per unit of time and that the centre of `hotspot' corresponds to a faster mantle upwelling velocity than its periphery. This is therefore in strong support of a model where ocean islands are associated with faster upwelling at depth. However, there is in fact not a simple relationship between melt productivity and upwelling velocities. Notably, the presence of volatiles, of mafic lithologies or of variably enriched peridotitic source could all affect melting rate and hence U-Th-Pa fractionation. We have considered these issues in great detail using a large data base for the Azores islands. While there are clear variations in mantle source composition, they cannot explain the observations of increasing 231Pa/235U ratio with distance from the centre of the Azores hotspot . If we take into account the effect of water in the source of the Azores, it clearly affects the scaling between U-series fractionation and upwelling velocity but not the overall conclusions.

  4. Accelerator Mass Spectrometry of Actinides in Ground- and Seawater: An Innovative Method Allowing for the Simultaneous Analysis of U, Np, Pu, Am, and Cm Isotopes below ppq Levels.

    Science.gov (United States)

    Quinto, Francesca; Golser, Robin; Lagos, Markus; Plaschke, Markus; Schäfer, Thorsten; Steier, Peter; Geckeis, Horst

    2015-06-02

    (236)U, (237)Np, and Pu isotopes and (243)Am were determined in ground- and seawater samples at levels below ppq (fg/g) with a maximum sample size of 250 g. Such high sensitivity was possible by using accelerator mass spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA) with extreme selectivity and recently improved efficiency and a significantly simplified separation chemistry. The use of nonisotopic tracers was investigated in order to allow for the determination of (237)Np and (243)Am, for which isotopic tracers either are rarely available or suffer from various isobaric mass interferences. In the present study, actinides were concentrated from the sample matrix via iron hydroxide coprecipitation and measured sequentially without previous chemical separation from each other. The analytical method was validated by the analysis of the Reference Material IAEA 443 and was applied to groundwater samples from the Colloid Formation and Migration (CFM) project at the deep underground rock laboratory of the Grimsel Test Site (GTS) and to natural water samples affected solely by global fallout. While the precision of the presented analytical method is somewhat limited by the use of nonisotopic spikes, the sensitivity allows for the determination of ∼10(5) atoms in a sample. This provides, e.g., the capability to study the long-term release and retention of actinide tracers in field experiments as well as the transport of actinides in a variety of environmental systems by tracing contamination from global fallout.

  5. Stuies of neptunium(V) sorption on montmorillonite, clinoptilolite, quartz and {alpha}-alumina

    Energy Technology Data Exchange (ETDEWEB)

    Bertetti, F.P.; Pabalan, R.T.; Turner, D.R.; Almendarez, M.G. [Southwest Research Institute, San Antonio, TX (United States)

    1996-10-01

    {sup 237}Np is a particular concern to the safety suitability of Yucca Mountain, Nevada, as a geologic repository for high-level nuclear wastes. In this study, montmorillonite, clinoptilolite, quartz, and {alpha}-alumina were reacted with {sup 237}Np-bearing solutions to characterize the sorption behavior of Np(V) on these minerals. Batch experiments were conducted at room temperature (20{plus_minus}2{degrees}C) over a range of conditions in which solution pH, sorbent surface area, initial concentration of N(V), ionic strength, and partial pressure of CO{sub 2} were varied. For all the minerals studied, Np(V) sorption begins at pH values coincident with the start of Np hydrolysis in solution ({approximately}6.5-7). For solutions undersaturated with respect to atmospheric CO{sub 2}, sorption increases continuously with increasing pH. For solutions at equilibrium with atmospheric CO{sub 2}, the {open_quotes}sorption envelope{close_quotes} is coincident with the calculated predominance field (pH {approximately}7-9.5) of the NpO{sub 2}(OH){sup 0}(aq) species, and sorption is inhibited at higher pH where neptunyl carbonate complexes predominate. Modeling of the sorption behavior of Np(V) was performed using a surface complexation-approach (Diffuse-Layer Model).

  6. Analytical method for the determination of Np and Pu in sea water by AMS with respect to the Fukushima accident

    Energy Technology Data Exchange (ETDEWEB)

    Hain, K., E-mail: karin.hain@mytum.de [Physics Department, Technische Universität München, James-Franck-Str.1, 85748 Garching (Germany); Faestermann, T.; Famulok, N.; Fimiani, L.; Gómez-Guzmán, J.M.; Korschinek, G. [Physics Department, Technische Universität München, James-Franck-Str.1, 85748 Garching (Germany); Kortmann, F.; Lierse von Gostomski, Ch. [Radiochemie München, Technische Universität München, Walther-Meißner-Str.3, 85748 Garching (Germany); Ludwig, P. [Physics Department, Technische Universität München, James-Franck-Str.1, 85748 Garching (Germany); Shinonaga, T. [Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Radiation Protection, Ingolstädter Landstrasse 1, 855764 Neuherberg (Germany)

    2015-10-15

    A chemical separation procedure for plutonium (Pu) and neptunium (Np) was developed using extraction chromatography, mass spectrometry and radiometric analysis to determine their concentrations and isotopic ratios in sea water. {sup 241}Am, which causes isobaric background to {sup 241}Pu in mass spectrometric measurements, was successfully separated from the Pu fraction by this method. Water samples which were spiked with {sup 242}Pu and {sup 237}Np or {sup 239}Np, respectively, were used for chemical yield determination. The chemical yields of Pu and Np, which were determined by alpha and gamma spectrometry at the Radiochemie München (RCM), of more than 85% were obtained. The developed method was applied to analyze the concentration of Pu and Np in the certified reference material, IAEA-443, by Accelerator Mass Spectrometry (AMS) at the Maier–Leibnitz-Laboratory (MLL) to check the applicability of the method to sea water samples. The concentrations of {sup 240}Pu, {sup 241}Pu and {sup 237}Np obtained in this study are in agreement with the certified and literature values within the uncertainties. Due to strong isotopic interference of {sup 239}Pu with {sup 238}U, it was not possible to analyze the concentration of {sup 239}Pu. Some modifications of the chemical separation method to suppress the uranium (U) fraction are under consideration. This method can be used for the analysis of Pu and Np in Pacific Ocean water samples collected after the Fukushima accident.

  7. Safe management of actinides in the nuclear fuel cycle: Role of mineralogy

    Science.gov (United States)

    Ewing, Rodney C.

    2011-02-01

    During the past 60 years, more than 1800 metric tonnes of Pu, and substantial quantities of the "minor" actinides, such as Np, Am and Cm, have been generated in nuclear reactors. Some of these transuranium elements can be a source of energy in fission reactions (e.g., 239Pu), a source of fissile material for nuclear weapons (e.g., 239Pu and 237Np), and of environmental concern because of their long-half lives and radiotoxicity (e.g., 239Pu and 237Np). There are two basic strategies for the disposition of these heavy elements: (1) to "burn" or transmute the actinides using nuclear reactors or accelerators; (2) to "sequester" the actinides in chemically durable, radiation-resistant materials that are suitable for geologic disposal. There has been substantial interest in the use of actinide-bearing minerals, especially isometric pyrochlore, A 2B 2O 7 (A = rare earths; B = Ti, Zr, Sn, Hf), for the immobilization of actinides, particularly plutonium, both as inert matrix fuels and nuclear waste forms. Systematic studies of rare-earth pyrochlores have led to the discovery that certain compositions (B = Zr, Hf) are stable to very high doses of alpha-decay event damage. Recent developments in our understanding of the properties of heavy element solids have opened up new possibilities for the design of advanced nuclear fuels and waste forms.

  8. EA-MC Neutronic Calculations on IAEA ADS Benchmark 3.2

    Energy Technology Data Exchange (ETDEWEB)

    Dahlfors, Marcus [Uppsala Univ. (Sweden). Dept. of Radiation Sciences; Kadi, Yacine [CERN, Geneva (Switzerland). Emerging Energy Technologies

    2006-01-15

    The neutronics and the transmutation properties of the IAEA ADS benchmark 3.2 setup, the 'Yalina' experiment or ISTC project B-70, have been studied through an extensive amount of 3-D Monte Carlo calculations at CERN. The simulations were performed with the state-of-the-art computer code package EA-MC, developed at CERN. The calculational approach is outlined and the results are presented in accordance with the guidelines given in the benchmark description. A variety of experimental conditions and parameters are examined; three different fuel rod configurations and three types of neutron sources are applied to the system. Reactivity change effects introduced by removal of fuel rods in both central and peripheral positions are also computed. Irradiation samples located in a total of 8 geometrical positions are examined. Calculations of capture reaction rates in {sup 129}I, {sup 237}Np and {sup 243}Am samples and of fission reaction rates in {sup 235}U, {sup 237}Np and {sup 243}Am samples are presented. Simulated neutron flux densities and energy spectra as well as spectral indices inside experimental channels are also given according to benchmark specifications. Two different nuclear data libraries, JAR-95 and JENDL-3.2, are applied for the calculations.

  9. Safe management of actinides in the nuclear fuel cycle: Role of mineralogy; La gestion des actinides dans le cycle du combustible nucleaire: le role de la mineralogie

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, R.C. [Department of Nuclear Engineering and Radiological Sciences, Department of Geological Sciences, Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-1005 (United States)

    2011-02-15

    During the past 60 years, more than 1800 metric tonnes of Pu, and substantial quantities of the 'minor' actinides, such as Np, Am and Cm, have been generated in nuclear reactors. Some of these transuranium elements can be a source of energy in fission reactions (e.g., {sup 239}Pu), a source of fissile material for nuclear weapons (e.g., {sup 239}Pu and {sup 237}Np), and of environmental concern because of their long-half lives and radiotoxicity (e.g., {sup 239}Pu and {sup 237}Np). There are two basic strategies for the disposition of these heavy elements: (1) to 'burn' or transmute the actinides using nuclear reactors or accelerators; (2) to 'sequester' the actinides in chemically durable, radiation-resistant materials that are suitable for geologic disposal. There has been substantial interest in the use of actinide-bearing minerals, especially isometric pyrochlore, A{sub 2}B{sub 2}O{sub 7} (A rare earths; B = Ti, Zr, Sn, Hf), for the immobilization of actinides, particularly plutonium, both as inert matrix fuels and nuclear waste forms. Systematic studies of rare-earth pyrochlores have led to the discovery that certain compositions (B = Zr, Hf) are stable to very high doses of alpha-decay event damage. Recent developments in our understanding of the properties of heavy element solids have opened up new possibilities for the design of advanced nuclear fuels and waste forms. (author)

  10. The influence of source heterogeneity on the U-Th-Pa-Ra disequilibria in post-glacial tholeiites from Iceland

    Science.gov (United States)

    Koornneef, J. M.; Stracke, A.; Bourdon, B.; Grönvold, K.

    2012-06-01

    We investigate the relative influence of mantle upwelling velocity and source heterogeneity on the melting rates recorded by 230Th-238U, 231Pa-235U and 226Ra-230Th disequilibria in post-glacial tholeiites from Iceland's main rift areas. The measured (230Th/238U) ratios range from 1.085 to 1.247, the (231Pa/235U) ratios from 1.333 to 1.925, and the (226Ra/230Th) ratios from 0.801 to 1.218. A general positive correlation between 230Th excesses and distance from the inferred plume centre is consistent with a model of decreasing mantle upwelling velocity with increasing distance from the plume axis. However, the model is not substantiated by the (231Pa/235U) data as the correlation with distance from the plume centre is weak. On the scale of individual eruption centres, the observed U-series are influenced by variations in melt transport time, source porosity, and local variations in mantle upwelling velocity. Broad correlations between (230Th/238U) and (231Pa/235U) and highly incompatible trace element ratios for samples from the Western Volcanic Zone provide, however, evidence for a significant underlying effect of source heterogeneity on the U-series data. Low 230Th and 231Pa excesses in enriched samples from the Western Volcanic Zone with high U/Th, Nb/U and Nb/La indicate that partial melts from an enriched source component, characterised by high melt productivity but low bulk DU/DTh, influence the U-series systematics of the erupted melts. These results re-affirm the presence of comparatively larger abundances of enriched material in the mantle source beneath the South Western Rift of Iceland, which has been suggested based on relationships between highly incompatible element and Pb isotope ratios in Icelandic basalts. Overall, our results highlight the importance of lithological heterogeneity on the melting behaviour of the upper mantle and the composition of oceanic basalts.

  11. Radioactivity levels and radiological hazard indices at the Saudi coastline of the Gulf of Aqaba

    Science.gov (United States)

    Al-Trabulsy, H. A.; Khater, A. E. M.; Habbani, F. I.

    2011-03-01

    The coast of the Gulf of Aqaba is subjected to several sources of pollution due to several activities occurring at the coastal area. The activities vary between industrial, tourist and other development aspects at the Jordanian coastline of the Gulf of Aqaba. Phosphate industry has been considered a major source polluting the marine environment. According to official reports, 4-7 million tons of raw phosphate is exported through the Gulf of Aqaba. During transportation and loading, a small proportion of this enters the waters of the Gulf. Phosphate dust has also been considered another source of nutrients loading to the Gulf. 19 sediment samples were collected along the Saudi Gulf coastline, from the Saudi-Jordan border down to the end of the Gulf at Tiran Strait. Measurements of the activity concentrations of 226Ra, 232Th, 40K and 137Cs in Bq/kg (in dry weight) of the collected samples were carried out using gamma-ray spectrometry based on a highly pure germanium coaxial detector (HPGe). The concentrations of 238U and 232Th were also determined using ICP-MS technique. The average specific activities for 226Ra, 232Th, 40K and 137Cs were found to be 11.4±1.5, 22.5±3.7, 641.1±61.3 and 3.5±0.7 Bq/kg, respectively. The results show that the mean activity of 226Ra and 232Th is lower than the world average of 25 Bq/kg for both of them, whereas the mean value for 40K is about double the world average of 370 Bq/kg. The presence of 137Cs in the analyzed samples is low in most locations. The mean concentrations of 238U and 232Th in the study area are 1.2 and 5.4 mg/kg, respectively, and the ratio 238U/ 232Th is 0.2, which is lower than the global ratio of 0.3. The ratio of 226Ra/ 228Ra was found to decrease southwards in the direction of Tiran Strait, away from the phosphate industry in Jordan. Mean values for radium equivalent, absorbed dose, annual effective dose, external and internal hazard index and representative level index were determined as: 92.9 Bq/kg, 45.6 n

  12. 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

  13. Initial 230Th and isotopic compositions of U and Th in a Holocene stalagmite from Ninh Binh, Vietnam

    Science.gov (United States)

    Shen, C.; Sung, Y.; Chen, Y.; Ho, W.; Wang, X.; Galang, C.; Cheng, H.; Edwards, R.; Burr, G.; Lam, D.

    2003-12-01

    The application of the 238U-234U-230Th disequilibrium dating technique to cave carbonates has provided access to a valuable source of Quaternary environmental information. For some speleothems, however, the initial Th associated with the incorporation of detrital materials into the growing carbonate matrix can bias the true ages, which play a pivotal role in the paleo-sciences. Isochron techniques and development diagrams (Cheng et al., 2000, {\\ G.C.A.}, 64, 2401-2416) were used on a stalagmite with unusually high thorium concentrations of 5-130 ppm and low uranium concentration of 100-300 ppb, collected from Ninh Binh, Vietnam, in order to evaluate the initial 230Th values, 230Th/232Th ratios and ages. Uranium and thorium concentrations and isotopic compositions for forty subsamples collected from eight horizons of this 4600-yr old speleothem were analyzed by ICP-MS techniques (Shen et al., 2002, {\\ Chem. Geology}, 185, 165-178). Results from the application of isochron techniques were: (1) 50-90% of the 230Th was deposited initially and must be subtracted from measured 230Th in order to obtain accurate ages; (2) in some cases, discordant ages were obtained among subsamples on the same horizon if the same initial of 230Th/232Th was used for correction; (3) there was some variability in the initial 230Th/232Th values for different layers. These observations indicate that there are many Th sources with different concentrations and 230Th/232Th ratios introduced into growing layers during crystallization. Accordingly, the initial values of 230Th/232Th ratios vary between and within horizons. Such heterogeneous coprecipitation of detrital materials places some limits on the utility of simple two-dimensional isochron approaches to speleothems with large and complicated Th contamination, which enhances the uncertainty of estimated ages. If the development diagram technique is also employed, the initial values of 230Th/232Th ratios are more tightly constrained, varying

  14. Radiological impacts of phosphogypsum.

    Science.gov (United States)

    Al Attar, Lina; Al-Oudat, Mohammad; Kanakri, Salwa; Budeir, Youssef; Khalily, Hussam; Al Hamwi, Ahmad

    2011-09-01

    This study was carried out to assess the radiological impact of Syrian phosphogypsum (PG) piles in the compartments of the surrounding ecosystem. Estimating the distribution of naturally occurring radionuclides (i.e. (226)Ra, (238)U, (232)Th, (210)Po and (210)Pb) in the raw materials, product and by-product of the Syrian phosphate fertilizer industry was essential. The data revealed that the concentrations of the radionuclides were enhanced in the treated phosphate ore. In PG, (226)Ra content had a mean activity of 318 Bq kg(-1). The uranium content in PG was low, ca. 33 Bq kg(-1), because uranium remained in the phosphoric acid produced. Over 80% of (232)Th, (210)Po and (210)Pb present partitioned in PG. The presence of PG piles did not increase significantly the concentration of (222)Rn or gamma rays exposure dose in the area studied. The annual effective dose was only 0.082 mSv y(-1). The geometric mean of total suspended air particulates (TSP) ca. 85 μg m(-3). The activity concentration of the radionuclides in filtrates and runoff waters were below the detection limits (ca. 0.15 mBq L(-1) for (238)U, 0.1 mBq L(-1) for (232)Th and 0.18 mBq L(-1) for both of (210)Po and (210)Pb); the concentration of the radionuclides in ground water samples and Qattina Lake were less than the permissible limits set for drinking water by the World Health Organisation, WHO, (10, 1 and 0.1 Bq L(-1) for (238)U, (232)Th and both of (210)Po and (210)Pb, respectively). Eastern sites soil samples of PG piles recorded the highest activity concentrations, i.e. 26, 33, 28, 61 and 40 Bq kg(-1) for (226)Ra, (238)U, (232)Th, (210)Po and (210)Pb, respectively, due to the prevailing western and north-western wind in the area, but remained within the natural levels reported in Syrian soil (13-32 Bq kg(-1) for (226)Ra, 24.9-62.2 Bq kg(-1) for (238)U and 10-32 Bq kg(-1) for (232)Th). The impact of PG piles on plants varied upon the plant species. Higher concentrations of the radionuclides were

  15. An intercomparison on radionuclides in environmental samples, Baltic-Danish co-operation project on radiation protection 2001-2003

    DEFF Research Database (Denmark)

    Nielsen, S.P.

    2004-01-01

    , 241Am, 226Ra, 232Th and 40K. The evaluation of analytical performance was based on comparison with median values, a 10% target standard deviation and statistical tests at the 99% level. For 137Cs the resultsfrom 10 out of 16 laboratories passed the evaluation tests. For 90Sr the results from 5 out...... of 12 laboratories passed the evaluation tests. For 60Co, 239,240Pu and 241Am two laboratories submitted results and both passed the tests. For the naturalradionuclides 226Ra, 232Th and 40K, only a few laboratories did not pass the tests. For all radionuclides combined, the results from 6 out of 16...... laboratories passed the evaluation tests. The results indicate that for several of the laboratories there isroom to improve the analytical quality on radionuclides in environmental samples to match an uncertainty corresponding to a relative standard deviation of 10%....

  16. Natural γ-ray-emitting radionuclides in Egyptian cement

    Institute of Scientific and Technical Information of China (English)

    A.M.EL-ARABI; A.ABBADY; A.H. EL-KAMEL; A. NOSIER; A. MOUSTAFA

    2005-01-01

    Samples of cement manufactured in Egypt and the raw materials have been analyzed using gamma-spectroscopy, in order to determine the concentration of natural radionuclides and associated radiological hazard. The mean of specific activity due to radionuclides of 226Ra, 232Th and 40K was found to be (20±4), (11± 2),(320±18) (gypsum), (41±8), (27±5), (410±27) (clay), (58±11), (18±3), (321±20) (iron ore) and (37.6±6), (11.8±3),phate resistant cement (S.R.C.), clinker and white cement, while the mean specific activities of 226Ra and 232Th are activities (concentrations) are in the same range as the data released in other countries. The calculated radiation hazard parameters for all the samples are still lower than the acceptable values in Egypt and other countries.

  17. Experiments on parity violation in the compound nucleus

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.D.

    1996-09-01

    Results from experiments that measure parity-violating longitudinal asymmetries in the scattering of epithermal neutrons from compound-nuclear resonances at the Manuel Lujan Neutron Scattering Center at Los Alamos are discussed. Parity non-conserving asymmetries have been observed for many p-wave resonances in a single target. Measurements were performed on several nuclei in the mass region of A-100 and A-230. The statistical model of the compound nucleus provides a theoretical basis for extracting mean-squared matrix elements from the experimental asymmetry data, and for interpreting the mean-squared matrix elements. The constraints on the weak meson-exchange couplings calculated from the compound-nucleus asymmetry data agree qualitatively with the results from few-body and light-nuclei experiments. For all nuclei but {sup 232}Th measured asymmetries have random signs. For {sup 232}Th eight of eight measured asymmetries are positive. This phenomenon is discussed in terms or doorway models.

  18. Evaluation of effective dose in consequence of Para chestnut ingestion; Avaliacao da dose efetiva em consequencia da ingestao de castanha do Para

    Energy Technology Data Exchange (ETDEWEB)

    Bellintani, Sandra A.; Oliveira, Joselens de; Carvalho, Jurandyr S. de; Hiromoto, Goro [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1995-12-31

    Commercial samples of Brazil nut tree seed (Bertholletia excelsa) were analysed for the presence or uranium and thorium series of natural radionuclides. The samples were analysed for the content of {sup 238} U, {sup 226} Ra, {sup 210} Pb, {sup 232} Th, {sup 228} Th. Mean values 1.4 {+-} 0.4 Bq/kg for {sup 238} U, 26.3{+-}4.1 Bq/kG for {sup 226} Ra, 4.7{sup {+-}}1.8 Bq/kg for {sup 210} Pb, 16.5{+-}4.3 Bq/kg for {sup 232} Th, 31.3{+-}6.4 Bq/Kg for {sup 228} Ra and 12.3{+-}5.1 Bq/kg for {sup 228} Th. The effective dose due to the ingestion of natural radionuclides contained in the Brazil nuts, is 2.6 x 10{sup -2} mSv/kg ingested per year. (author). 9 refs., 1 tab.

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

    Science.gov (United States)

    Pham, M K; van Beek, P; Carvalho, F P; Chamizo, E; Degering, D; Engeler, C; Gascó, C; Gurriaran, R; Hanley, O; Harms, A V; Herrmann, J; Hult, M; Ikeuchi, Y; Ilchmann, C; Kanisch, G; Kis-Benedek, G; Kloster, M; Laubenstein, M; Llaurado, M; Mas, J L; Nakano, M; Nielsen, S P; Osvath, I; Povinec, P P; Rieth, U; Schikowski, J; Smedley, P A; Suplinska, M; Sýkora, I; Tarjan, S; Varga, B; Vasileva, E; Zalewska, T; Zhou, W

    2016-03-01

    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: (40)K, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (234)U, (238)U, (239)Pu, (239+240)Pu and (241)Am for IAEA-410 and (40)K, (137)Cs, (210)Pb ((210)Po), (226)Ra, (228)Ra, (228)Th, (232)Th, (235)U, (238)U, (239)Pu, (240)Pu and (239+240)Pu for IAEA-412. The CRMs can be used for quality assurance and quality control purposes in the analysis of radionuclides in sediments, for development and validation of analytical methods and for staff training. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Determination of thorium by ICP-MS and ICP-OES.

    Science.gov (United States)

    Holmes, L

    2001-01-01

    Natural thorium (232-Th) has traditionally been measured by radiometric techniques such as alpha and gamma spectrometry. However. with both ICP-OES and ICP-MS instruments becoming relatively common in many analytical laboratories. these techniques have become more acceptable in thorium analysis. This paper will briefly describe an overview of the instrumentation currently available and the techniques themselves applied to thorium analysis. Both techniques have low detection limits and require little sample treatment after the sample digestion. Routine sample analysis time is short and spectra easy to interpret. usually giving results with low uncertainties, Whereas ICP-OES measures total thorium only, ICP-MS also offers the potential to measure other long-lived thorium isotopes (t 1/2 > 10(4) years), such as 232Th. However, other important isotopes, such as 228Th. are still out of reach for routine analysis. The main disadvantage of the techniques is the requirement for a sample digestion stage.

  1. Fusion reactions with the one-neutron halo nucleus 15C

    CERN Document Server

    Alcorta, M; Back, B B; Bedoor, S; Bertone, P F; Deibel, C M; DiGiovine, B; Esbensen, H; Greene, J P; Hoffmann, C R; Jiang, C L; Lighthall, J C; Marley, S T; Pardo, R C; Paul, M; Rogers, A M; Ugalde, C; Wuosmaa, A H

    2011-01-01

    The structure of 15C, with an s1/2 neutron weakly bound to a closed-neutron shell nucleus 14C, makes it a prime candidate for a one-neutron halo nucleus. We have for the first time studied the cross section for the fusion-fission reaction 15C + 232Th at energies in the vicinity of the Coulomb barrier and compared it to the yield of the neighboring 14C + 232Th system measured in the same experiment. At sub-barrier energies, an enhancement of the fusion yield by factors of 2-5 was observed for 15C, while the cross sections for 14C match the trends measured for 12,13C.

  2. Evaluation of radioactive emissions of lignite-fired power plants in Turkey using the Analytic Hierarchy Process

    Energy Technology Data Exchange (ETDEWEB)

    Bueke, Tayfun [Mugla Sitki Kocman Univ., Mugla (Turkey). Dept. of Energy Systems Engineering

    2013-11-15

    Radioactive emissions of 13 lignite-fired power plants in Turkey are of great concern to the public and to scientists alike. The purpose of this study is to evaluate these power plants, according to their radioactive emissions by using the Analytic Hierarchy Process. Control criteria are in particular {sup 226}Ra, {sup 232}Th, {sup 40}K and {sup 238}U emissions from the power plants. These control criteria are weighted according to the objective assessment. The calculations are repeated for three different objective assessments of control criteria namely the mortality risk coefficients for inhalation, ingestion, external exposure of {sup 226}Ra, {sup 232}Th, {sup 40}K and {sup 238}U. It has been calculated that the Can lignite-fired power plant is ranking first while the Soma-B plant is ranking last according to the radioactive emissions of the power plants when the average of three different objective control criteria are used in the calculations. (orig.)

  3. THE INVESTIGATION OF BURNUP CHARACTERISTICS USING THE SERPENT MONTE CARLO CODE FOR A SODIUM COOLED FAST REACTOR

    Directory of Open Access Journals (Sweden)

    MEHMET E. KORKMAZ

    2014-06-01

    Full Text Available In this research, we investigated the burnup characteristics and the conversion of fertile 232Th into fissile 233U in the core of a Sodium-Cooled Fast Reactor (SFR. The SFR fuel assemblies were designed for burning 232Th fuel (fuel pin 1 and 233U fuel (fuel pin 2 and include mixed minor actinide compositions. Monte Carlo simulations were performed using Serpent Code1.1.19 to compare with CRAM (Chebyshev Rational Approximation Method and TTA (Transmutation Trajectory Analysis method in the burnup calculation mode. The total heating power generated in the system was assumed to be 2000 MWth. During the reactor operation period of 600 days, the effective multiplication factor (keff was between 0.964 and 0.954 and peaking factor is 1.88867.

  4. Use of thorium as tracer on study of groundwater of Botucatu sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Paulo Augusto d' A.; Menezes, Maria Angela B.C. de; Moreira, Rubens Martins; Reis Junior, Aluisio Souza; Kastner, Geraldo Frederico, E-mail: paap@cdtn.br, E-mail: menezes@cdtn.br, E-mail: rubens@cdtn.br, E-mail: reisas@cdtn.br, E-mail: gfk@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Thorium in some mineral compounds is very difficult to be dissolved in aqueous medium. To study the mobility of thorium in water, one alternative is to complex this element with EDTA, becoming possible to follow the behavior of thorium this medium. This way, in groundwater with low natural radioactivity and low {sup 232}Th activity, thorium can be used as a tracer. This paper describes the application of the complex Th-EDTA as a tracer applying the solution trough a sandstone sample made by rock from Botucatu Sandstone. The objective was to simulate the flow of groundwater inside the original rock aiming at future use of rare-earth elements complexed with EDTA as tracer. Alpha spectrometry technique was used to determine {sup 232}Th in the water samples with {sup 230}Th as inner-standard. (author)

  5. Gamma-Ray Measurements of Naturally Occurring Radioactive Materials in Sludge, Scale and Well Cores of the Oil Industry in Southern Iraq

    Directory of Open Access Journals (Sweden)

    Abdul Ridha Hussain SUBBER

    2013-12-01

    Full Text Available Radioactivity of nuclides 238U, 226Ra, 232Th and 40K was measured in soil by γ-ray spectrometry using a NaI (Li detector. A criterion was set in order to analyze sludge samples from oil fields and oil well-cores in southern Basrah, in the Iraq oil fields. More than 3 γ-ray energy peaks were used for the determination of 226Ra and 232Th activity concentrations to obtain results that are more accurate. Relationships between the measured radionuclides were discussed. Radionuclides 238U and 226Ra were found in disequilibrium with ratio of specific activities (238 U/226 Ra less than unity for most of the sludge and core samples. The content of radioactive elements in the sludge, scale and well core is found within the range of other petroleum countries in the region.doi:10.14456/WJST.2014.93

  6. The Status of Natural Radioactivity and Heavy Metals Pollution on Marine Sediments Red Sea Coast, At Safaga, Egypt

    OpenAIRE

    2016-01-01

    Natural 226Ra, 232Th and 40K radio nuclides concentration in beach Sediments along Safaga coast of Red sea, Egypt has been carried out using a NaI (Tl) gamma ray spectrometric technique. The total average concentrations of radionuclides ± uncertainty of 226Ra, 232Th and 40K were 22.2 ± 1.7, 19.2 ± 2.5, and 477.6 ± 27.6 Bq kg-1 , respectively. The total average absorbed dose rate is found to be 41.4 nGyh-1 , whereas the annual effective dose rate has an average value of 54 µSvy-1. The total or...

  7. Afyon-Sandıklı-Şuhut Arasındaki Bölgenin Toryum Konsantrasyonunun Alansal Dağılımı

    Directory of Open Access Journals (Sweden)

    N. Ayten UYANIK

    2014-07-01

    Full Text Available Although at least 20 elements are known as natural radioactive, only U (Uranium, Th (Thorium and K (Potassium are important elements in nuclear geophysics. Stable nucleus of 232Th is Pb and in this chain there are 10 isotopes. 208Tl decay chain produces characteristic gamma radiation (2.62 MeV. The 232Th concentrations have been measured using portable gamma-ray spectrometer, for about 180 seconds counting times at 1169 points with known geographical coordinates. The variation of eTh concentration has been mapped in Afyonkarahisar district (Sandıklı, Şuhut, Haydarlı. eTh concentration values ranged between 0-80 ppm with different regional lithology. It should be noted that high concentration values were obtained in volcanic rocks and altered volcanic zones

  8. Numerical design of the Seed-Blanket Unit for the thorium nuclear fuel cycle

    Directory of Open Access Journals (Sweden)

    Oettingen Mikołaj

    2016-01-01

    Full Text Available In the paper we present the Monte Carlo modelling by the means of the Monte Carlo Continuous Energy Burn-up Code of the 17x17 Pressurized Water Reactor fuel assembly designed according to the Radkowsky Thorium Fuel concept. The design incorporates the UO2 seed fuel located in the centre and (Th,UO2 blanket fuel located in the peripheries of fuel assembly. The high power seed region supplies neutrons for the low power blanket region and thus induces breeding of fissile 233U from fertile 232Th. The both regions are physically separated and thus this approach is also known as either the heterogonous approach or the Seed-Blanket Unit. In the numerical analysis we consider the time evolutions of infinite neutron multiplication factor, axial/radial power density profile, 233U, 235U and 232Th.

  9. Environmental consequences of uranium atmospheric releases from fuel cycle facility: II. The atmospheric deposition of uranium and thorium on plants.

    Science.gov (United States)

    Pourcelot, L; Masson, O; Renaud, P; Cagnat, X; Boulet, B; Cariou, N; De Vismes-Ott, A

    2015-03-01

    Uranium and thorium isotopes were measured in cypress leaves, wheat grains and lettuce taken in the surroundings of the uranium conversion facility of Malvési (South of France). The comparison of activity levels and activity ratios (namely (238)U/(232)Th and (230)Th/(232)Th) in plants with those in aerosols taken at this site and plants taken far from it shows that aerosols emitted by the nuclear site (uranium releases in the atmosphere by stacks and (230)Th-rich particles emitted from artificial ponds collecting radioactive waste mud) accounts for the high activities recorded in the plant samples close to the site. The atmospheric deposition process onto the plants appears to be the dominant process in plant contamination. Dry deposition velocities of airborne uranium and thorium were measured as 4.6 × 10(-3) and 5.0 × 10(-3) m s(-1), respectively.

  10. Nuclear energy release from fragmentation

    CERN Document Server

    Li, Cheng; Tsang, M B; Zhang, Feng-Shou

    2015-01-01

    Nuclear energy released by splitting Uranium and Thorium isotopes into two, three, four, up to eight fragments with nearly equal size are studied. We found that the energy released come from equally splitting the $^{235,238}$U and $^{230,232}$Th nuclei into to three fragments is largest. The statistical multifragmentation model is employed to calculate the probability of different breakup channels for the excited nuclei. Weighing the the probability distributions of fragments multiplicity at different excitation energies for the $^{238}$U nucleus, we found that an excitation energy between 1.2 and 2 MeV/u is optimal for the $^{235}$U, $^{238}$U, $^{230}$Th and $^{232}$Th nuclei to release nuclear energy of about 0.7-0.75 MeV/u.

  11. Limits on uranium and thorium bulk content in GERDA Phase I detectors

    CERN Document Server

    Agostini, 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; Csathy, J Janicsko; 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

    2016-01-01

    Internal contaminations of $^{238}$U, $^{235}$U and $^{232}$Th in the bulk of high purity germanium detectors are potential backgrounds for experiments searching for neutrinoless double beta decay of $^{76}$Ge. 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 $^{226}$Ra, $^{227}$Ac and $^{228}$Th, the long-lived daughter nuclides of $^{238}$U, $^{235}$U and $^{232}$Th, respectively, have been derived. With these upper limits a background index in the energy region of interest from $^{226}$Ra and $^{228}$Th contamination is estimated which satisfies the prerequisites of a future ton scale germanium double beta decay experiment.

  12. Characterization of monazite dust particles

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Kenya Dias da; Juliao, Ligia; Santos, Maristela; Fernandes, Paulo; BBusch, Miliane; Nascimento, Sheila; Sousa, Wanderson [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)]. E-mail: kenya@ird.gov.br; Pedrero, Zoyne; Leite, Carlos V. Barros [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)]. E-mail: cvbl@vdg.puc-rio.br

    2002-07-01

    The aim of this work is to evaluate exposure of inhabitant of high background area to monazite airborne particles. The main deposit of mineral sands and the most important mineral processed plant is located in Buena village, a seashore village in the North of Rio de Janeiro state. The Buena inhabitants (about 300 persons) live around the plant. People living in regions with high concentration of monazite can be contaminated by ingestion of local foodstuff and inhalation of monazite airborne particles containing thorium. The elemental mass concentration, {sup 232} Th, {sup 228} Th and {sup 228} Ra concentrations in the respirable fraction of aerosols, MMAD (Mass Median Aerodynamic Diameter) of airborne particles and {sup 232} Th, {sup 228} Th and {sup 228}Ra concentrations in feces samples of the Buena village inhabitant were determined. (author)

  13. Mussels (Mytilus galloprovincialis) as a bio-indicator species in radioactivity monitoring of Eastern Adriatic coastal waters.

    Science.gov (United States)

    Krmpotić, Matea; Rožmarić, Martina; Barišić, Delko

    2015-06-01

    Croatian Adriatic coastal waters are systematically monitored within the Mediterranean Mussel Watch Project using mussels (Mytilus galloprovincialis) as a bio-indicator species. The study includes determination of naturally occurring ((7)Be, (40)K, (232)Th, (226)Ra and (238)U), as well as anthropogenic (137)Cs radionuclides. Activity concentrations in dry weight of mussels' soft tissue along the Croatian Adriatic coast are presented, with spatial and seasonal variations given and discussed. Samples were collected in spring and autumn for the period between 2009 and 2013. Radionuclides were determined by gamma-ray spectrometry. Activity concentrations of (7)Be were the highest in spring periods, especially in the areas with significant fresh water discharges. Activity concentrations of (40)K did not vary significantly with season or location. (137)Cs activities were low, while (232)Th, (226)Ra and (238)U activities were mostly below the detection limit of performed gamma-spectrometric measurement.

  14. The investigation of burnup characteristics using the serpent Monte Carlo code for a sodium cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Korkmaz, Mehmet E.; Agar, Osman [Karamanoglu Mehmetbey University, Faculty of Kamil Oezdag Science, Karaman (Turkmenistan)

    2014-06-15

    In this research, we investigated the burnup characteristics and the conversion of fertile {sup 232}Th into fissile {sup 233}U in the core of a Sodium-Cooled Fast Reactor (SFR). The SFR fuel assemblies were designed for burning {sup 232}Th fuel (fuel pin 1) and {sup 233}U fuel (fuel pin 2) and include mixed minor actinide compositions. Monte Carlo simulations were performed using Serpent Code1.1.19 to compare with CRAM (Chebyshev Rational Approximation Method) and TTA (Transmutation Trajectory Analysis) method in the burnup calculation mode. The total heating power generated in the system was assumed to be 2000 MWth. During the reactor operation period of 600 days, the effective multiplication factor (keff) was between 0.964 and 0.954 and peaking factor is 1.88867.

  15. 家装木材的放射性分析%Analyse Radioactivity of Decor Wood

    Institute of Scientific and Technical Information of China (English)

    郑贤利; 赵越; 屈国普; 罗鸣文

    2012-01-01

    通过分析家装木材中的放射性比活度及内外照射指数,结果表明:不同原木中的放射性含量不同,均为40K>226Ra>232Th;复合板E0级的放射性高于E1级;分析的样品均能用作室内的装饰材料.%Through the analysis of the radioactive specific activity, exposures inside and outside the index in decor wood, the results shows that the radioactive content is different in different logs, are 40K > 226 Ra >232Th and the radioactive content of E0 Composite board is higher than El. Analysis of samples can be used for indoor decoration materials.

  16. Thorium mobilization in groundwaters from Aguas da Prata, Sao Paulo state; Mobilizacao de torio em aguas subterraneas de Aguas da Prata, estado de Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Tonetto, Erica Martini [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Area de Concentracao Geociencias e Meio Ambiente. Pos-Graduacao em Geociencias]. E-mail: etonetto@rc.unesp.br; Bonotto, Daniel Marcos [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Dept. de Petrologia e Metalogenia]. E-mail: dbonotto@rc.unesp.br

    2002-09-15

    The paper describes and discusses results of the determination, by alpha spectrometry, of the natural thorium isotopes in groundwaters associated with different rock types in Aguas da Prata spa, state of Sao Paulo. The dissolved Thorium is relatively low (0.003 to 1.72 mg.L{sup -1} for {sup 232}Th), while the {sup 22}'8Th/{sup 232}Th isotopic ratios for dissolved thorium were higher than unity (1.8 to 34). The thorium concentration in suspended solids of these waters ranged between 183 up and 3445 mug.g{sup -1} and indicates that significant thorium transport occurs under this condition. The obtained results allowed to calculate the factor for preferential mobilization of thorium in particulate matter relative to the liquid phase, an important parameter for understanding the geochemical behaviour of this element in hydrosphere. (author)

  17. The Average Lifetime of Giant Composite Systems Formed in Strongly Damped Collisions

    Institute of Scientific and Technical Information of China (English)

    TIAN Jun-Long; WU Xi-Zhen; OU Li; LI Zhu-Xia

    2007-01-01

    The dynamic, adiabatic and diabatic entrance potentials in strongly damped reactions of 238 U+238 U, 232Th+250 Cf are calculated and compared. The feature of the dynamical potential implies that it is possible for the composite systems to stick together for a period of time. By means of the improved quantum molecular dynamics model the time evolution of the density and charge distributions of giant composite systems and their fragments for reactions 238U+238U, 232Th+250Cf are investigated, from which the lifetimes of giant composite systems at different energies are obtained. The longest average lifetime of 238 U+238 U is found when the incident energy is about Ec.m.=1080 Me V, which is about 1200 fm/c.

  18. Absence of {sup 232,230,228}Th enhancement decay by ultrasound exposure

    Energy Technology Data Exchange (ETDEWEB)

    Aupiais, J. [CEA DAM DIF, Arpajon (France); Cousin, V.; Nikitenko, S.I.; Pflieger, R. [Marcoule Institute for Separation Chemistry, ICSM, UMR 5257, Bagnols-sur-Ceze (France); Moisy, P. [CEA, Bagnols-sur-Ceze (France). RadioChemistry and Processes Dept.

    2013-08-01

    We report on our attempt to reproduce the {sup 228}Th decay enhancement under the effect of power ultrasound claimed recently in the literature. The evolution of natural thorium isotopic composition ({sup 232}Th, {sup 230}Th, and {sup 228}Th) in various aqueous solutions submitted to 20 kHz power ultrasound (0.18 W mL{sup -1}, 20 C, Ar). The radioactivities of the three isotopes of thorium ({sup 232}Th, {sup 230}Th and {sup 228}Th) were followed by a liquid scintillation counting technique. No change was detected during ultrasonic irradiation. Our results demonstrate that under the studied conditions the rate of Th isotopes radioactive decay is not modified under the effect of ultrasound on aqueous solutions of thorium salts. (orig.)

  19. Impact of Thorium Capture Cross Section Uncertainty on the Thorium Utilized ADS Reactivity Calculation

    Directory of Open Access Journals (Sweden)

    Thanh Mai Vu

    2014-01-01

    Full Text Available Recently, the researches on fast neutron spectrum system utilized thorium fuel are widely conducted. However, the recent thorium cross section libraries are limited compared to uranium cross section libraries. The impact of thorium cross section uncertainty on thorium fuel utilized accelerator driven system (ADS reactivity calculation is estimated in this study. The uncertainty of the keff caused by 232Th capture cross section of JENDL-4.0 is about 1.3%. The uncertainty of JENDL-4.0 is needed to be enhanced to provide more reliable results on reactivity calculation for the fast system. The impact of uncertainty of  232Th capture cross section of ENDF/B-VII is small (0.1%. Therefore, it will cause no significant impact of the thorium cross section library on the thorium utilized ADS design calculation.

  20. Measurement of the total activity concentrations of Libyan oil scale

    Science.gov (United States)

    Da Silva, F. C. A.; Bradley, D. A.; Regan, P. H.; Rozaila, Z. Siti

    2017-08-01

    Twenty-three oil scale samples obtained from the Libyan oil and gas industry production facilities onshore have been measured using high-resolution gamma-ray spectrometry with a shielded HPGe detector, the work being carried out within the Environmental Radioactivity Laboratory at the University of Surrey. The main objectives of this work were to determine the extent to which the predominant radionuclides associated with the uranium and thorium natural decay chains were in secular equilibrium with their decay progeny, also to compare differences between the total activity concentrations (TAC) in secular equilibrium and disequilibrium and to evaluate the measured activities for the predominant gamma-ray emitting decay radionuclides within the 232Th and 238U chains. The oil scale NORM samples did not exhibit radioactive equilibrium between the decay progeny and longer-lived parent radionuclides of the 238U and 232Th series.

  1. Measurement of neutron-induced activation cross-sections using spallation source at JINR and neutronic validation of the Dubna code

    Indian Academy of Sciences (India)

    Manish Sharma; V Kumar; H Kumawat; J Adam; V S Barashenkov; S Ganesan; S Golovatiouk; S K Gupta; S Kailas; M I Krivopustov; H S Palsania; V Pronskikh; V M Tsoupko-Sitnikov; N Vladimirova; H Westmeier; W Westmeier

    2007-02-01

    A beam of 1 GeV proton coming from Dubna Nuclotron colliding with a lead target surrounded by 6 cm paraffin produces spallation neutrons. A Th-foil was kept on lead target (neutron spallation source) in a direct stream of neutrons for activation and other samples of 197Au, 209Bi, 59Co, 115In and 181Ta were irradiated by moderated beam of neutrons passing through 6 cm paraffin moderator. The gamma spectra of irradiated samples were analyzed using gamma spectrometry and DEIMOS software to measure the neutron cross-section. For this purpose neutron fluence at the positions of samples is also estimated using PREPRO software. The results of cross-sections for reactions 232Th(, ), 232Th(, 2), 197Au(, ), 197Au(, ), 197Au(, ), 59Co(, ), 59Co(, ), 181Ta(, ) and 181Ta(, ) are given in this paper. Neutronics validation of the Dubna Cascade Code is also done using cross-section data by other experiments.

  2. Distribution of uranium and thorium in groundwater of arid climate region

    Science.gov (United States)

    Murad, Ahmed; Alshamsi, Dalal; Aldahan, Ala; Hou, Xiaolin

    2014-05-01

    Uranium, thorium and their decay products are the most common radionuclides in groundwater in addition to potassium-40. Once groundwater is used for drinking, domestic and irrigation purposes, the radionuclides will then pose environmental and health related hazard originating from radioactivity and toxicity. In the investigation presented here, assessment of 238U, 235U and 232Th concentrations in groundwater across of the United Arab Emirates (UAE) is evaluated in terms of quality and sources. The region is dominated by arid climate conditions and radioactivity assessment of groundwater is essential for safe use of groundwater. Furthermore, the results were linked to data from other arid regions and worldwide. Groundwater samples (total dissolved solids,TDS, 142.5 mg L-1 to 12770 mg L-1) from 67 different wells were collected across geomorphologically different areas and most of the wells are actively used for agriculture. The aquifers are recent sand dunes, Quaternary (3 million years to present) sediments, and older carbonate rocks (230-10 million years). The 235U, 238U and 232Th measurements were carried out using ICP-MS system equipped with an Xt-skimmer cone and a concentric nebulizer under hot plasma conditions. Concentrations of 235U, 238U and 232Th range at (0.125-508.4) ng L-1, (25.81-69237) ng L-1 and (0.236-2529) ng L-1, respectively. Apparently, most 235U, 238U, 232Th concentrations in the sampled groundwater are below the WHO proposed permissible level of 60000 ng/L for total uranium (1 Bq L-1 for 235U and 10 Bq L-1 for 238U) and 5000 ng L-1 (1Bq L-1) for 232Th. A few samples show high concentrations of uranium that are associated with high TDS values and occur within interbedded limestones and shales aquifer. Comparison with worldwide groundwater data suggests that 238U concentration is highest in the arid regions groundwater where the recharge to aquifers is relatively low. The situation for 232Th concentrations seems less affected by climatic

  3. Radiological Impact of Phosphogypsum Application in Agriculture

    Science.gov (United States)

    Dias, Nivea M. P.; Caires, Eduardo F.; Pires, Luiz F.; Bacchi, Marcio A.; Fernandes, Elisabete A. N.

    2010-08-01

    Phosphogypsum (PG) contains radionuclides from 238U and 232Th decay series. Due to the presence of these radionuclides, many countries restricted the use of PG in agriculture, however there is not such restriction in Brazil. The main objective of this work was to evaluate the impact of PG application on 226Ra (238U) and 228Ra (232Th) concentrations in soil. Gamma-spectrometry was carried out using HPGe detector. No increment of 226Ra and 228Ra was observed for increasing PG doses. Average values found for 226Ra and 228Ra were respectively 37 Bq kg-1 and 57 Bq kg-1. The results showed that the increasing PG doses in the specific conditions of the experiment did not cause a significant increment of radionuclides.

  4. Evaluation of excess life time cancer risk due to natural radioactivity of the Lignite samples of the Nichahoma, lignite belt, North Kashmir, India

    Energy Technology Data Exchange (ETDEWEB)

    Ashraf, Mudasir [VIT Univ., Vellore, Tamil Nadu (India). Photonic, Nuclear and Medical Physics Div.; Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar (India). Dept. of Radiological Physics and Bio-engineering; Radha, C. Anu; Ramasubramanian, V. [VIT Univ., Vellore, Tamil Nadu (India). Photonic, Nuclear and Medical Physics Div.; Ahmad, Shakeel; Masood, Sajad [Kashmir Univ., Srinagar (India). Dept. of Physics; Dar, Rayees Ahmad [Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar (India). Div. of Biostatistics

    2016-11-01

    Naturally occurring radionuclides of the {sup 226}Ra, {sup 232}Th, and {sup 40}K present in the lignite samples was measured by using a low-background Pb-shielded gamma spectroscopic counting assembly utilizing NaI(Tl) detector for the measurement and to evaluation the radiation hazard indices and excess life time cancer risk. The average values of specific activity concentrations in the investigated lignite samples was found to be 45.36 Bq kg{sup -1} for {sup 226}Ra, 21.42 Bq kg{sup -1} for {sup 232}Th, 40.51 Bq kg{sup -1} for {sup 40}K and 79.11 Bq kg{sup -1} for Ra{sub eq} respectively. The average value excess life time cancer risk was found to be relatively higher than the world average. Moreover, the correlation analysis shows the strong dependence of excess lifetime cancer risk on measured dose and the radium equivalent activity.

  5. Experimental and Simulation of Gamma Radiation Dose Rate for High Exposure Building Material

    CERN Document Server

    Abbasi, Akbar

    2015-01-01

    Natural radioactivity concentrations in high exposure building materials are commonly used in Iran, which is measured a direct exposure by using {\\gamma}-ray spectrometry. The values for 226Ra, 232Th and 40K were in the ranges 3.8 - 94.2, 6.5 - 172.2 and 556.9 - 1539.2 Bqkg-1, respectively. The absorbed dose rates in the standard dwelling room due to 238U, 232Th series and 40K were calculated with MCNPX code. The simulation and experimental results were between 7.95 - 41.74 and 8.36 - 39.99 nGy h-1, respectively. These results were compared with experimental outing and there was overlap closely. The simulation results are able to develop for any kind of dwelling places.

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

    Directory of Open Access Journals (Sweden)

    D.A.E. Darwish

    2015-01-01

    Full Text Available Gamma ray spectra of natural radioactivity from 238U- and 232Th series and from 40K of eight (representing 40 collected samples granite samples collected from Saint Katherine region, South Sinai, Egypt, had been measured using a gamma-ray spectrometer with an HPGe detector. The results reported in the present article include: Specific activities (A of 226Ra, 232Th and 40K radionuclides, Radium equivalent activities (Raeq, external and internal hazard indices (Hext, Hint, external and internal level indices (Iγ, Iα, activity utilization index (I, exposure rate (ER and other important parameters to the subject. The results have been presented in table graphs with the permissible maximum limits.

  7. Measuring radioactivity level in various types of rice using NaI (Tl detector

    Directory of Open Access Journals (Sweden)

    Laith A. Najam

    2015-03-01

    Full Text Available A study of long- lived gamma emitting radionuclides in rice consumed in Nineveh Province (IRAQ were performed. The study targeted the natural radionuclides 226Ra, 232Th and 40K .The rice samples originated from seven different countries. NaI(Tl detector was used to measure the radionuclides level. The radioactivity concentrations of 226Ra, 232Th and 40K ranged from 51.15 to 109.26 Bq/kg,13.67 to 71.97 Bq/kg and 231.87 to 691.71Bq/kg. In order to evaluate the radiological hazard of the natural radioactivity, radium equivalent activity, gamma absorbed dose rate, internal and external hazard indices , gamma index and finally alpha index have been calculated . Hence rice consumption in Nineveh province (IRAQ is radiologically safe for the presence of the investigated radionuclides.

  8. Effect of reducing groundwater on the retardation of redox-sensitive radionuclides

    Directory of Open Access Journals (Sweden)

    Rose TP

    2008-12-01

    Full Text Available Abstract Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions were designed to simulate subsurface conditions at the Nevada Test Site (NTS, where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing conditions, radionuclide distribution coefficients varied with the mineralogic composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for 99Tc (from 1.22 at oxidizing to 378 mL/g at mildly reducing conditions and 237Np (an increase from 4.6 to 930 mL/g in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for 99Tc, which tends to be mobile under oxidizing conditions. A review of the literature suggests that iodine sorption should decrease under reducing conditions when I- is the predominant species; this was not consistently observed in batch tests. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI reduction to U(IV. Sorption of Pu was not affected by the decreasing Eh conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH4. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides 99Tc and 237Np, which are commonly identified as long-term dose contributors in the risk

  9. Determination of {sup 236}U and transuranium elements in depleted uranium ammunition by {alpha}-spectrometry and ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Desideri, D.; Meli, M.A.; Roselli, C.; Testa, C. [General Chemistry Institute, Urbino University, Urbino (Italy); Boulyga, S.F.; Becker, J.S. [Central Department of Analytical Chemistry, Research Centre Juelich, Juelich (Germany)

    2002-11-01

    It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products ({sup 236}U, {sup 239}Pu, {sup 240}Pu, {sup 241}Am, and {sup 237}Np) in the ammunition. In this work the analysis of actinides by {alpha}-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. {sup 242}Pu and {sup 243}Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri-n-octylamine (TNOA), with a decontamination factor higher than 10{sup 6}; after elution plutonium was determined by ICP-MS ({sup 239}Pu and {sup 240}Pu) and {alpha}-spectrometry ({sup 239+240}Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10{sup -12} g g{sup -1} and 2 x 10{sup -11} g g{sup -1}. The {sup 240}Pu/{sup 239}Pu isotope ratio in one penetrator sample (0.12{+-}0.04) was significantly lower than the {sup 240}Pu/{sup 239}Pu ratios found in two soil samples from Kosovo (0.35{+-}0.10 and 0.27{+-}0.07). {sup 241}Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 10{sup 7}. The concentration of {sup 241}Am in the penetrator samples was 2.7 x 10{sup -14} g g{sup -1} and <9.4 x 10{sup -15} g g{sup -1}. In addition {sup 237}Np was detected at ultratrace levels. In general, ICP-MS and {alpha}-spectrometry results were in good agreement.The presence of anthropogenic radionuclides ({sup 236}U, {sup 239}Pu,{sup 240}Pu, {sup 241}Am, and {sup 237}Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of

  10. Determination of (236)U and transuranium elements in depleted uranium ammunition by alpha-spectrometry and ICP-MS.

    Science.gov (United States)

    Desideri, D; Meli, M A; Roselli, C; Testa, C; Boulyga, S F; Becker, J S

    2002-11-01

    It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products ((236)U, (239)Pu, (240)Pu, (241)Am, and (237)Np) in the ammunition. In this work the analysis of actinides by alpha-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. (242)Pu and (243)Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri- n-octylamine (TNOA), with a decontamination factor higher than 10(6); after elution plutonium was determined by ICP-MS ((239)Pu and (240)Pu) and alpha-spectrometry ((239+240)Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10(-12) g g(-1) and 2 x 10(-11) g g(-1). The (240)Pu/(239)Pu isotope ratio in one penetrator sample (0.12+/-0.04) was significantly lower than the (240)Pu/(239)Pu ratios found in two soil samples from Kosovo (0.35+/-0.10 and 0.27+/-0.07). (241)Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 10(7). The concentration of (241)Am in the penetrator samples was 2.7 x 10(-14) g g(-1) and <9.4 x 10(-15) g g(-1). In addition (237)Np was detected at ultratrace levels. In general, ICP-MS and alpha-spectrometry results were in good agreement. The presence of anthropogenic radionuclides ((236)U, (239)Pu,(240)Pu, (241)Am, and (237)Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of radionuclides are very low, their radiotoxicological effect is negligible.

  11. Developing an 'atomic clock' for fission lifetime measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wilschut, H.W.; Kravchuk, V.L

    2004-04-05

    The relevance of measuring fission lifetimes of hot nuclei is briefly discussed. It is shown that K X-ray emission prior to fission can be used to measure fission lifetimes. The preparation of the K-shell hole, the simultaneous nuclear excitation, and the analysis of the X-ray spectra is described. First results of a measurement using a {sup 20}Ne beam of 30 MeV/nucleon on a {sup 232}Th target are reported.

  12. Emission of intermediate mass fragments during fission

    Science.gov (United States)

    Chen, S. L.; de Souza, R. T.; Cornell, E.; Davin, B.; Hamilton, T. M.; Hulbert, D.; Kwiatkowski, K.; Lou, Y.; Viola, V. E.; Korteling, R. G.; Wile, J. L.

    1996-11-01

    Ternary fission in the reaction 4He + 232Th at Elab=200 MeV has been observed. Intermediate mass fragments (IMF: 3fission. The widths of the energy spectra are relatively constant for neck fragments with Z>=4, suggesting little variability in the scission configurations. A linear dependence of on Z is observed for the neck IMFs. The observed trend is compared with a Coulomb trajectory model.

  13. Natural radionuclides in urine- and faeces samples; Natuerliche Radionuklide in Urin- und Stuhlproben

    Energy Technology Data Exchange (ETDEWEB)

    Froning, M.; Burow, M.; Ennen, R.; Hoelters, A.; Laumen-Sentis, S.; Zoriy, M. [Forschungszentrum Juelich GmbH (Germany). Geschaeftsbereich Sicherheit und Strahlenschutz

    2016-07-01

    In interpreting of measurement data for incorporation monitoring by excretion samples a clear distinction between the natural intake and the fraction subjected due to occupational exposure should be performed. At the present only a few data about an excretion of primordial elements such as {sup 238}U, {sup 232}Th are available in the literature. In the following study actual data measured in urine and faeces will be presented and discussed.

  14. Environmental radioactivity assessment for Bayburt, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Kucukomeroglu, B; Kurnaz, A; Cevik, U [Department of Physics, Karadeniz Technical University, Trabzon (Turkey); Damla, N [Department of Physics, Batman University, Batman (Turkey); Celebi, N; Ataksor, B; Taskin, H [Cekmece Nuclear Research and Training Centre, Altinsehir Yolu, Halkali, Istanbul (Turkey)], E-mail: ndamla@ktu.edu.tr

    2009-09-01

    This study assesses the results of environmental radioactivity measurements for Bayburt Province in the Eastern Black Sea area of Turkey. Using {gamma}-ray spectrometry, activity concentrations of the natural radionuclides {sup 226}Ra, {sup 232}Th and {sup 40}K and a fission product {sup 137}Cs were investigated in soil samples. The activity concentrations of {sup 226}Ra, {sup 232}Th and {sup 40}K in various building materials such as sand, cement and marble and in drinking waters were determined. The activity concentrations vary from 16 to 54 Bq kg{sup -1} for {sup 226}Ra, from 10 to 21 Bq kg{sup -1} for {sup 232}Th and from 113 to 542 Bq kg{sup -1} for {sup 40}K in building materials. The mean specific activity concentrations of {sup 226}Ra, {sup 232}Th and {sup 40}K in drinking waters were 93, 30 and 504 mBq l{sup -1}, respectively. The concentrations of gross {alpha} and {beta} radioactivity in drinking water samples collected from four different sampling stations have been determined. The results show that the gross {alpha} and {beta} activities are lower than the screening levels given by the World Health Organization (WHO), which are a maximum contaminant level of 0.5 Bq l{sup -1} and 1.0 Bq l{sup -1} gross {alpha} and {beta} radioactivity, respectively, in drinking water. Indoor radon measurements were made in 44 dwellings in Bayburt by using Cr-39 detectors. Radon concentrations in dwellings in Bayburt varied from 17 to 125 Bq m{sup -3} and the average value was 56 Bq m{sup -3}. The results obtained in this study indicate that the region has a background radiation level that is within the typical natural range and shows no significant departures from other parts of the country.

  15. 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.

  16. Radionuclide distribution of Holocene sediments and its effects on the habitat of recent foraminifers: A case study from the Western Marmara Sea (Turkey)

    Science.gov (United States)

    Ünal Yumun, Zeki; Kam, Erol; Murat Kılıc, Ali

    2017-04-01

    ABSTRACT Radionuclides cause radioactive contamination in aquatic environments just as other non-biodegradable pollutants, such as heavy metals, sink to the seafloor and accumulate in the sediments. These radioactive pollutants especially affect benthic foraminifera living on the sediment surface or in the sediments in the seafloor. Foraminifera were used as bioindicators to analyze the effect of radioactivity pollution on ecosystems. In this study, we have investigated natural and artificial radionuclide (232Th, 226Ra, 40K and 137Cs) distribution in sediment samples taken in the living areas of benthic foraminifera in the Western Marmara Sea by means of gamma spectrometry. Accordingly, 29 core samples taken in 2016 from depths of about 20-35 m close to the shores of the Marmara Sea were used. Core samples representing the pollution of the study area were collected at locations such as discharge points for domestic and industrial areas, port locations, and others. Other samples were taken from areas unaffected or less affected by pollution. The radionuclide concentration activity values in the sediment samples obtained from the locations, in Bq/kg, were 137Cs, 0.9-9.4; 232Th, 18.9-86; 226Ra, 10-50; 40K, 24.4-670. These values were compared with the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) data, and an environmental analysis was carried out. The 226Ra series, the 232Th series, and the 40K radionuclides accumulate naturally, and they are also increasing continuously due to anthropogenic pollution. Although the 226Ra values obtained throughout the study areas remained within normal limits according to the UNSCEAR values, the 40K and 232Th series values were found to be higher in almost all locations. According to these results, the main causes of radioactive pollution in the investigation area are agricultural and mining activities. Keywords: Ra-226, Th-232, K-40, Cs-137, radionuclide, Western Marmara Sea, Foraminifera

  17. The procedure and results of calculations of the equilibrium isotopic composition of a demonstration subcritical molten salt reactor

    Science.gov (United States)

    Nevinitsa, V. A.; Dudnikov, A. A.; Blandinskiy, V. Yu.; Balanin, A. L.; Alekseev, P. N.; Titarenko, Yu. E.; Batyaev, V. F.; Pavlov, K. V.; Titarenko, A. Yu.

    2015-12-01

    A subcritical molten salt reactor with an external neutron source is studied computationally as a facility for incineration and transmutation of minor actinides from spent nuclear fuel of reactors of VVER-1000 type and for producing 233U from 232Th. The reactor configuration is chosen, the requirements to be imposed on the external neutron source are formulated, and the equilibrium isotopic composition of heavy nuclides and the key parameters of the fuel cycle are calculated.

  18. Preliminary survey of outdoor gamma dose rates in Lesvos Island (Greece).

    Science.gov (United States)

    Petalas, Anastasios B; Vogiannis, Efstratios; Nikolopoulos, Dimitrios; Halvadakis, Constantinos P

    2005-01-01

    This study reports the first attempt to record the radioactive background due to gamma radiation in Lesvos Island (Greece). The study reports the results from 335 outdoor total gamma effective dose rate measurements conducted using GPS navigation and a Geiger-Muller detector (Bicron, Micro Sievert) on the whole surface of the island together with a digital map produced by appropriate mapping GIS programme. The study also reports the measurements of outdoor gamma dose rates due to the 238U, 232Th and 40K radionuclides as estimated via in situ gamma-ray spectrometry measurements performed at 26 sites using a 3 x 3 inch NaI (thallium activated) portable detector. The results from the outdoor total gamma effective dose rates range between 0.0023 and 0.28 microSv h(-1). The highest outdoor total gamma effective dose rates (0.013-0.28 microSv h(-1)) were detected in the northeastern part of the island and the intermediate rates (0.066-0.13 microSv h(-1)) in the central region. The outdoor gamma dose rates due to 238U, 232Th and 40K radionuclides range between 1.7 +/- 0.8 and 154 +/- 7 nGy h(-1) with an average of 86 +/- 6 nGy h(-1). The average contribution of each of the examined radionuclides (238U, 232Th and 40K) to the total gamma dose rate was found to be equal to 12 +/- 4% for 238U, 58 +/- 6% for 232Th and 29 +/- 7% for 40K, respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

    Santos Junior, Jose Araujo dos [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Quimica]. E-mail: jaraujo@ufpe.br; Cardoso, Jorge Joao Ricardo Ferreira [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Geologia]. E-mail: jcardoso@ufpe.br; Amaral, Romilton dos Santos; Leoterio, Dilmo Marques da Silva [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Radioecologia (RAE)]. E-mail: romilton@ufpe.br; Menezes, Romulo Simoes Cezar [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Fertilidade de Solos]. E-mail: rmenezes@ufpe.br; Silva, Cleomacio Miguel da [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Fisica]. E-mail: cleomacio@hotmail.com; Rocha, Edilson Accioly [Centro Federal de Educacao Tecnologica de Pernambuco, Recife, PE (Brazil)]. E-mail: edilsonaccioly@cefetpe.br

    2007-07-01

    Levels of natural radioactivity are the major cause of external exposure to gamma radiation. Based on this parameter, natural radioactivity of {sup 238}U, {sup 232}Th and {sup 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{sup 2}, around an anomaly of uranium in rock, were analyzed. The activities of {sup 238}U were evaluated by the 63 keV photopeak of {sup 234}Th, that of {sup 232}Th by the 338, 911 and 969 keV peak of {sup 228}Ac, and that of {sup 40}K by its 1,461 keV peak. The mean of the activities for these radionuclides were 91 Bq.kg{sup -1} (median 88 Bq.kg{sup -1}) for the {sup 238}U, {sup 228} Bq.kg{sup -1} (median 215 Bq.kg{sup -1}) for the {sup 232}Th and 1,827 Bq.kg{sup -1} (median 1,662 Bq.kg{sup -1}) for the {sup 40}K. The anomalous rock did not present neither associated thorium nor potassium (values below the limit of detection: < 10 Bq.kg{sup -1} of {sup 232}Th and < 62 Bq.kg{sup -}'1 of {sup 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)

  20. Assessments of radioactivity concentration of natural radionuclides and radiological hazard indices in sediment samples from the East coast of Tamilnadu, India with statistical approach.

    Science.gov (United States)

    Ravisankar, R; Chandramohan, J; Chandrasekaran, A; Prince Prakash Jebakumar, J; Vijayalakshmi, I; Vijayagopal, P; Venkatraman, B

    2015-08-15

    This paper reports on the distribution of three natural radionuclides (238)U, (232)Th and (40)K in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a NaI(Tl) detector based γ-spectrometry. The mean activity concentration is ⩽2.21, 14.29 and 360.23Bqkg(-1) for (238)U, (232)Th and (40)K, respectively. The average activity of (232)Th, (238)U and (40)K is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of (238)U, (232)Th and (40)K to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (Hex) internal hazard index (Hin), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended values. Therefore, coastal sediments do not to pose any significant radiological health risk to the people living in nearby areas along East coast of Tamilnadu. The data obtained in this study will serve as a baseline data in natural radionuclide concentration in sediments along the coastal East coast of Tamilnadu. Copyright © 2015 Elsevier

  1. Nuclear fuels for hybrid reactors; Combustiveis para reatores hibridos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Antonio T. e; Souza, Ubiratan C. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Dept. de Reatores. E-mail: teixeira@net.ipen.br

    2000-07-01

    This paper presents thermal and thermal-hydraulics analysis for two core types proposed for a Fast Energy Amplifier utilizing, respectively, mixed oxides and metallic fuels. The mixed oxide fuels is of type ThO{sub 2} + 0,1{sup 233} U, and the metallic fuel is of type {sup 232} Th + 30% TRU. The analysis results permit to establish the necessary design parameters to be utilized in an irradiation performance analysis of these fuels. (author)

  2. Natural Radioactivity of Beach Sand Samples in the Tripoli Region, Northwest Libya

    OpenAIRE

    2008-01-01

    A comprehensive study was conducted to determine the radioactivity concentrations of beach sand samples from different sites along the coast of Tripoli, northwest Libya, using high resolution g-ray spectroscopy. Collection of samples was carried out during low tide, where it was possible to collect sediments from the wet region that was covered by sea water during high tide. From the measured g-ray spectra, elemental concentrations were determined for 226Ra, 232Th, 40K, and 210Pb at...

  3. Spectral interference corrections for the measurement of (238)U in materials rich in thorium by a high resolution gamma-ray spectrometry.

    Science.gov (United States)

    Yücel, H; Solmaz, A N; Köse, E; Bor, D

    2009-11-01

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

  4. 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.

  5. Natural radioactivity level in materials used for medieval vaulting in the territory of the central Balkan region

    OpenAIRE

    Bjelić Igor S.; Todorović Dragana J.; Krneta-Nikolić Jelena D.; Lazarević Đorđe R.; Stanković Koviljka Đ.

    2016-01-01

    This work presents the results of an investigation undertaken to determine the level of natural radioactivity in the traditional building materials used for medieval indoor vaulted constructions in the territory of the central Balkan region. Indoor radiation exposure varies appreciably if it comes from the earth building materials, hence the presence of natural radioisotopes of 226Ra, 232Th, and 40K in masonry vaulted constructions was analyzed using gamma ...

  6. Evaluation of Differences in Response of DOD Portable Instruments and Solid-State Detectors used by MEXT for Measurement of External Radiations with Attention to the Cosmic Radiation Component

    Science.gov (United States)

    2014-03-01

    reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching...in reported results that is operator-induced. Third, an under-response of MEXT solid- state scintillators , such as thallium-activated sodium iodide...naturally-occurring radioactive materials in the environment are 232Th (and radioactive decay products), 238U (and radioactive decay products), and 40K

  7. Complexity Theory of Beam Halo-Chaos and Its Control Methods With Prospective Applications

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This article offers an overview and comprehensive survey of the complexity theory of beamhalo-chaos and its control methods with prospective applications. In recent years, there has been growinginterest in proton beams of high power linear accelerator due to its attractive features in possiblebreakthrough applications, such as production of nuclear materials (e.g., tritium, transforming 232Th to233U), transmutation of radioactive wastes, productions of radioactive isotopes for medical use, heavy ion

  8. 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.

  9. Enrichment and particle size dependence of polonium and other naturally occurring radionuclides in coal ash.

    Science.gov (United States)

    Sahu, S K; Tiwari, M; Bhangare, R C; Pandit, G G

    2014-12-01

    Coal fired thermal power contributes 70% of power in India. Coal fired power generation results in huge amounts of fly ash and bottom ash of varying properties. Coal, which contains the naturally occurring radionuclides, on burning results in enrichment of these radionuclides in the ashes. In the present study, coal, bottom ash and fly ash samples collected from six coal-fired power plants in India were measured for (210)Po using alpha spectrometry and for natural U, (226)Ra, (232)Th and (40)K by an HPGe γ-ray spectrometer. (210)Po in fly ash ranged from 25.7 to 70 Bq/kg with a mean value of 40.5 Bq/kg. The range and mean activities of (238)U, (226)Ra, (232)Th, (40)K in fly ash were 38.5-101 (78.1), 60-105.7 (79), 20-125 (61.7) and 43.6-200 (100) Bq/kg respectively. Fly ash and bottom ash contains two to five times more natural radionuclides than feed coal. The results were compared with the available data from earlier studies in other countries. The effect of particle size on enrichment factor of the nuclides in fly ash was studied. (210)Po showed the largest size dependence with its concentration favoring the smaller particle size while (232)Th showed least size dependence. (238)U and (226)Ra showed behavior intermediate to that of (210)Po and (232)Th. Also the correlation between sulfur content of the feed coal and activity of (210)Po was investigated. Increased sulfur content in feed coal enhanced enrichment of (210)Po in ash. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. The procedure and results of calculations of the equilibrium isotopic composition of a demonstration subcritical molten salt reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nevinitsa, V. A., E-mail: Neviniza-VA@nrcki.ru; Dudnikov, A. A.; Blandinskiy, V. Yu.; Balanin, A. L.; Alekseev, P. N. [National Research Centre Kurchatov Institute (Russian Federation); Titarenko, Yu. E.; Batyaev, V. F.; Pavlov, K. V.; Titarenko, A. Yu., E-mail: yuri.titarenko@itep.ru [Institute for Theoretical and Experimental Physics (Russian Federation)

    2015-12-15

    A subcritical molten salt reactor with an external neutron source is studied computationally as a facility for incineration and transmutation of minor actinides from spent nuclear fuel of reactors of VVER-1000 type and for producing {sup 233}U from {sup 232}Th. The reactor configuration is chosen, the requirements to be imposed on the external neutron source are formulated, and the equilibrium isotopic composition of heavy nuclides and the key parameters of the fuel cycle are calculated.

  11. Study of pollution in the El Jadida-Safi Atlantic coastal zone (Morocco) by using PIXE and SSNTD methods

    OpenAIRE

    2008-01-01

    International audience; In this work PIXE experiments were performed for measuring heavy and light elements (ranging from aluminium to lead) concentrations inside various polluted and unpolluted soils as well as liquid samples collected from different phosphate factory sewers in the El Jadida-Safi Atlantic coastal region (Morocco). In addition, uranium (238U) and thorium (232Th) contents were evaluated in the same samples studied by using CR-39 and LR-115 type II solid state nuclear track det...

  12. Radioactivity in rocks and soil and interaction with groundwater in an arid region

    Science.gov (United States)

    Alshamsi, Dalal; Murad, Ahmed; Aldahan, Ala; Hou, Xiaolin; El Saiy, Ayman

    2014-05-01

    Interaction of groundwater with soil and rocks changes the chemical composition of the water both spatially and temporally. In arid regions, surficial recharge of groundwater is generally limited to sporadic rainfall events which may cause rapid interaction between the recharge water and the aquifers materials. Among the elements that commonly increase in concentration as groundwater interact with the aquifer materials are the radioactive elements such as uranium and thorium and their decay chain products. Here, we present data on 235U, 238U, 232Th as well as 137Cs in some sediments and rock aquifers located in the United Arab Emirates (UAE) in southeastern Arabian Peninsula. The Quaternary sediments are composed of silt, sand and gravel with varying proportions of quartz, carbonates, feldspars, evaporites, while the carbonates are mainly limestones, dolomitic limestones, dolomite and calcareous mudstones. These carbonate rocks cover ages extending from 10-230 Myr. After complete digestion using fluoric and nitric acids and chemical separation, the isotopes were measured using ICP-MS. The 235U, 238U and 232Th concentrations ranges are 2.66-32.5 ng/g, 354.7-4453 ng/g and 13.2-1367 ng/g respectively in the carbonate rocks. In the sediments the concentrations are 4.6-17.5 ng/g for 235U, 631.7-2406 ng/g for 238U and 25.6-799.6 ng/g for 232Th. Although it is difficult to quantify the amounts of uranium isotopes that enter the hydrological system from the aquifers, it seems that in the presence of carboxyl ions, uranium forms highly soluble complexes which can be transported to large distances in groundwater. The variations in 232Th concentrations are probably controlled by the availability of sulfate salt rocks (like gypsum) interacting with thorium and forming soluble thorium compounds which can also explain the highly variable concentrations in groundwater.

  13. Levels of Radioactivity in the Cuban Marine Environment

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C.A.; Asencio, M.D.; Caravaca, A.M.; Morell, E.S.; Claro, R.M

    1998-07-01

    The National Sampling Programme has been initiated to determine the levels of natural and artificial radioactivity in the Cuban Marine Environment. Samples of water, sediment and marine life were analysed. The levels of {sup 40}K, {sup 226}Ra, {sup 232}Th, {sup 210}Po, {sup 137}Cs and {sup 90}Sr in components of the marine environment are described. The materials and methods used for the work are those recommended by the Centre of Radiation Protection and Hygiene and accepted internationally. (author)

  14. Distribution of radionuclides in different parts of a mushroom: Influence of the degree of maturity

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, Antonio [Department of Physics, Veterinary Faculty, University of Extremadura, Avda de la Universidad s/n, 10071 Caceres (Spain)]. E-mail: ymiralle@unex.es; Guillen, Fco. Javier [Department of Physics, Veterinary Faculty, University of Extremadura, Avda de la Universidad s/n, 10071 Caceres (Spain); Salas, Alejandro [Department of Physics, Veterinary Faculty, University of Extremadura, Avda de la Universidad s/n, 10071 Caceres (Spain); Manjon, Jose Luis [Department of Plant Biology, Faculty of Sciences, University of Alcala, 28871 Alcala de Henares, Madrid (Spain)

    2006-04-15

    Mushrooms are known to be bioaccumulators of radionuclides, but little is known about their distribution within the fruiting bodies or the influence of the degree of maturity on uptake. We carried out a series of cultures of the species Pleurotus eryngii under controlled laboratory conditions to analyze these variables. The maximal uptake of {sup 134}Cs and {sup 85}Sr was found to occur in mature fruiting bodies, and with the growth of the mushroom the distribution of radionuclides within the fruiting bodies became inhomogeneous. In particular, there was an exponential increase in the percentage of the total activity of {sup 134}Cs, {sup 85}Sr, and {sup 6}Co in the cap + gills as the fruiting bodies matured, accompanied by a complementary decrease in the stem. Radiocaesium, potassium, calcium, {sup 239+24}Pu, {sup 234,238}U, {sup 228,230,232}Th, and {sup 226}Ra were assayed in the cap, gills, and stem of fruiting bodies of Tricholoma equestre collected in a natural ecosystem and cultured P. eryngii. Potassium and radiocaesium were mainly located in the cap + gills, and {sup 226}Ra in the gills. There was a disequilibrium between {sup 230,232}Th and {sup 228}Th in the different parts of the fungi, probably due to uptake of {sup 228}Ra and subsequent decay to {sup 228}Th. Finally, the distribution pattern of{sup 239+24}Pu, {sup 234,238}U, and {sup 230,232}Th seemed to be species dependent.

  15. Environmental and radio-ecological studies on shallow marine sediments from harbour areas along the Red Sea coast of Egypt for identification of anthropogenic impacts.

    Science.gov (United States)

    El-Taher, Atef; Madkour, Hashem A

    2014-01-01

    Analysis of marine sediments of the studied localities provides investigators with data to characterise the composition of these sediments allowing for the identification of particular pollution sources. A study of texture, geochemistry, X-ray diffraction and natural radionuclide content of shallow marine sediments from Quseir harbour, Safaga harbour and El-Esh area in the Red Sea coast of Egypt was conducted for the purpose of assessing the possible influence of human activities on the composition of the sediments. The activity concentrations of the naturally occurring radionuclides (226)Ra, (232)Th and (40)K were measured by using γ-ray spectrometry. The mean activity concentrations of (226)Ra, (232)Th and (40)K in all areas studied were found to be 71±6, 66±5 and 92±7 Bq kg(-1) for (226)Ra, 83±5, 71±7 and 162±23 Bq kg(-1) for (232)Th and 513±10, 493±20 and 681±28 Bq kg(-1) for (40)K, respectively. The results of the study presented were compared with corresponding results obtained in other coastal and aquatic environments in the Red Sea.

  16. An Ultra-Low Background PMT for Liquid Xenon Detectors

    CERN Document Server

    Akerib, D S; Bernard, E; Bernstein, A; Bradley, A; Byram, D; Cahn, S B; Carmona-Benitez, M C; Carr, D; Chapman, J J; Chan, Y-D; Clark, K; Coffey, T; deViveiros, L; Dragowsky, M; Druszkiewicz, E; Edwards, B; Faham, C H; Fiorucci, S; Gaitskell, R J; Gibson, K R; Hall, C; Hanhardt, M; Holbrook, B; Ihm, M; Jacobsen, R G; Kastens, L; Kazkaz, K; Larsen, N; Lee, C; Lesko, K; Lindote, A; Lopes, M I; Lyashenko, A; Malling, D C; Mannino, R; McKinsey, D; Mei, D; Mock, J; Morii, M; Nelson, H; Neves, F; Nikkel, J A; Pangilinan, M; Pech, K; Phelps, P; Shutt, T; Silva, C; Skulski, W; Solovov, V N; Sorensen, P; Spaans, J; Stiegler, T; Sweany, M; Szydagis, M; Taylor, D; Thomson, J; Tripathi, M; Uvarov, S; Verbus, J R; Walsh, N; Webb, R; White, J T; Wlasenko, M; Wolfs, F L H; Woods, M; Zhang, C

    2012-01-01

    Results are presented from radioactivity screening of two models of photomultiplier tubes designed for use in current and future liquid xenon experiments. The Hamamatsu 5.6 cm diameter R8778 PMT, used in the LUX dark matter experiment, has yielded a positive detection of four common radioactive isotopes: 238U, 232Th, 40K, and 60Co. Screening of LUX materials has rendered backgrounds from other detector materials subdominant to the R8778 contribution. A prototype Hamamatsu 7.6 cm diameter R11410 MOD PMT has also been screened, with benchmark isotope counts measured at <0.4 238 U / <0.3 232 Th / <8.3 40 K / 2.0+-0.2 60 Co mBq/PMT. This represents a large reduction, equal to a change of \\times 1/24 238U / \\times 1/9 232Th / \\times 1/8 40K per PMT, between R8778 and R11410 MOD, concurrent with a doubling of the photocathode surface area (4.5 cm to 6.4 cm diameter). 60Co measurements are comparable between the PMTs, but can be significantly reduced in future R11410 MOD units through further material selec...

  17. Rapid collection of iron hydroxide for determination of Th isotopes in seawater.

    Science.gov (United States)

    Okubo, Ayako; Obata, Hajime; Magara, Masaaki; Kimura, Takaumi; Ogawa, Hiroshi

    2013-12-04

    This work introduces a novel method of recovery of iron hydroxide using a DIAION CR-20 chelating resin column to determine Th isotopes in seawater with a sector field (SF) inductively coupled plasma mass spectrometer (ICP-MS). Thorium isotopes in seawater were co-precipitated with iron hydroxide, and this precipitate was sent to chelating resin column. Ferric ions in the iron hydroxide were bonded to functional groups of the chelating resin directly, resulting in a pH increase of the effluent by release of hydroxide ion from the iron hydroxide. The co-precipitated thorium isotopes were quantitatively collected within the column, which indicated that thorium was retained on the iron hydroxide remaining on the chelating column. The chelating column quantitatively collected (232)Th with iron hydroxide in seawater at flow rates of 20-25 mL min(-1). Based on this flow rate, a 5 L sample was processed within 3-4 h. The >20 h aging of iron hydroxide tends to reduce the recovery of (232)Th. The rapid collection method was successfully applied to the determination of (230)Th and (232)Th in open-ocean seawater samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Assay methods for U-238, Th-232, and Pb-210 in lead and calibration of Bi-210 bremsstrahlung emission from lead

    CERN Document Server

    Orrell, John L; Arnquist, Isaac J; Eggemeyer, Tere A; Glasgow, Brian D; Hoppe, Eric W; Keillor, Martin E; Morley, Shannon M; Myers, Allan W; Overman, Cory T; Shaff, Sarah M; Thommasson, Kimbrelle S

    2015-01-01

    Assay methods for measuring 238U, 232Th, and 210Pb concentrations in refined lead are presented. The 238U and 232Th concentrations are determined using isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) after anion exchange column separation of dissolved lead samples. The 210Pb concentration is inferred through {\\alpha}-spectroscopy of a daughter isotope, 210Po, after chemical precipitation separation on dissolved lead samples. Subsequent to the 210Po {\\alpha}-spectroscopy assay, a method for evaluating 210Pb concentrations in solid lead samples was developed via measurement of bremsstrahlung radiation from \\b{eta}-decay of a daughter isotope, 210Bi, by employing a 14-crystal array of high purity germanium (HPGe) detectors. Ten sources of refined lead were assayed. The 238U concentrations were <34 microBq/kg and the 232Th concentrations ranged <0.6-15 microBq/kg, as determined by the ICP-MS assay method. The 210Pb concentrations ranged from ~0.1-75 Bq/kg, as inferred by the 210Po ...

  19. A radiological survey of the Eğrigöz granitoid, Western Anatolia/Turkey.

    Science.gov (United States)

    Canbaz Öztürk, B; Yaprak, G; Çam, N F; Candan, O

    2015-06-01

    A radiological survey of the granitoid areas throughout Western Anatolia was conducted during 2007-14. As a part of this radiological survey, this article presents results obtained from Eğrigöz pluton, which lies in the northeastern region of Western Anatolia. In the investigated area, the activity measurements of the natural gamma-emitting radionuclides ((226)Ra, (232)Th and (40)K) in the granitic rock samples and soils have been carried out by means of the NaI(Tl) gamma-ray spectrometry system. The activity concentrations of the relevant natural radionuclides in the granite samples appeared in the ranges as follows: (226)Ra, 28-95 Bq kg(-1); (232)Th, 50-122 Bq kg(-1) and (40)K, 782-1365 Bq kg(-1), while the typical ranges of the (226)Ra, (232)Th and (40)K activities in the soil samples were found to be 7-184, 11-174 and 149-1622 Bq kg(-1), respectively. Based on the available data, the radiation hazard parameters associated with the surveyed rocks/soils are calculated. The corresponding absorbed dose rates in air from all those radionuclides were always much lower than 200 nGy h(-1) and did not exceed the typical range of worldwide average values noted in the UNSCEAR (2000) report. Furthermore, the data are also used for the mapping of the surface soil activity of natural radionuclides and the corresponding gamma dose rates of the surveyed area.

  20. Natural Radioactivity in Tanzania Cements and their Raw Materials

    Directory of Open Access Journals (Sweden)

    Aloyce Isaya Amasi

    2014-10-01

    Full Text Available This paper presents the study of natural radioactivity in Tanzania Portland cements and their raw materials. Samples collected as raw materials were pozzolan, sandstone, limestone, clay, gypsum and cement as finished products. The natural radioactivity due to the presence of radium 226Ra, thorium 232Th and potassium 40K were measured by means of gamma spectrometer coupled with HPGe detector. The mean measured activity concentrations of 226Ra, thorium 232Th and potassium 40K in the raw materials range from 2.6 to 93.2, 1.3 to 172.8 and 6.3 to 997 Bq/kg, respectively with higher activity concentrations in pozzolan and lower in gypsum. Activity concentrations of natural radionuclides in raw materials (excluding some materials from Songwe deposits in Mbeya region are comparative with the worldwide average concentrations of these radionuclides in soil. The average activity concentration of 226Ra, thorium 232Th and potassium 40K in the cements are 46, 28 and 228 Bq/kg, respectively. The calculated values of radiological indices are below 60% of the upper recommended values for building materials. The average annual effective dose to an occupant from use of these materials equals to 0.45 mSv. Average activity concentrations of the mentioned radionuclides in Tanzania cements are in the middle of the variability interval of the national averages.

  1. Radon and Thoron Exhalation Rates from Surface Soil of Bangka - Belitung Islands, Indonesia

    Directory of Open Access Journals (Sweden)

    Syarbaini Syarbaini

    2015-03-01

    Full Text Available DOI:10.17014/ijog.2.1.35-42Radon and thoron exhalation rate from soil is one of the most important factors that can influence the radioactivity level in the environment. Radon and thoron gases are produced by the decay of the radioactive elements those are radium and thorium in the soil, where its concentration depends on the soil conditions and the local geological background. In this paper, the results of radon and thoron exhalation rate measurements from surface soil of Bangka Belitung Islands at thirty six measurement sites are presented. Exhalation rates of radon and thoron were measured by using an accumulation chamber equipped with a solid-state alpha particle detector. Furthermore, the correlations between radon and thoron exhalation rates with their parent nuclide (226Ra and 232Th concentrations in collected soil samples from the same locations were also evaluated. The result of the measurement shows that mostly the distribution of radon and thoron is similar to 226Ra and 232Th, eventhough it was not a good correlation between radon and thoron exhalation rate with their parent activity concentrations (226Ra and 232Th due to the environmental factors that can influence the radon and thoron mobilities in the soil. In comparison to a world average, Bangka Belitung Islands have the 222Rn and 220Rn exhalation rates higher than the world average value for the regions with normal background radiation.

  2. α谱法测定低微量铀、钍含量的研究

    Institute of Scientific and Technical Information of China (English)

    夏明; 周秀云

    1982-01-01

    Alpha-spectrometric technique is described as an independent method of determining micro-content of U233 and Th233. This method is based on the comparison of U234 and Th233 alpha spectral activity in geological samples with U232 and Th233 spectral activity contributed by the spike of known concentration. The experiment procedure consists in dissolving fine powdered sample with acid and adding a given amount of U232-Th223 spike. The uranium and thorium are then separated by ion exchange. After purification each fraction is mounted on a separate stainless steel disk for measurement by alpha spectrometer which consist essentially of a surface barrier deterctor and a low noise amplification system connected to a multichannel analyser. After correcting for background, tail and other factors, the desired U232 and Th232 concentrations can be calculated. The data obtained by the alpha-spectrometric method using U232-Th223 spike are compared with colorimetric determination. Excellent agreement is obtained between the two sets of results. The coefficient of correlation is about 0.98 for U234 and 0.97 for Th232. The accuracy of uranium and thorium analyses by this method depends primarily upon the counting statistics of U233, U232, Th233 and Th223 and, to a lesser extent, upon the calibration of U233-Th238 spike. Errors of uranium and thorium concentration by this method are generally 2 to 5 per cent.

  3. Measurement of natural radionuclides and dose assessment of granites from Ondo State, Nigeria; Mesure des radionucleides naturels et de l'evaluation de la dose de granits de l'Etat d'Ondo, Nigeria

    Energy Technology Data Exchange (ETDEWEB)

    Ademola, J.A.; Ayeni, A.A. [Department of Physics, University of Ibadan, Ibadan (Nigeria)

    2010-10-15

    The activity concentrations of {sup 226}Ra, {sup 232}Th and {sup 40}K in fifty granite samples collected from five different quarry industries in Ondo State, Nigeria, were determined using gamma-ray spectrometry. The mean activity concentrations for each industry ranged from 16.7(6.4) to 85.4(23.0), 62.4(10.1) to 113.6(7.6), and 1315(136) to 1551(84) Bq.kg{sup -1} for {sup 226}Ra, {sup 232}Th and {sup 40}K, respectively. The values in parenthesis are the standard deviations. When compared with results from some parts of the world, the {sup 226}Ra and {sup 232}Th contents were lower, whereas the {sup 40}K content was similar. Using different approaches to estimate the potential radiological hazard of the samples, the results obtained were below the recommended maximum limits. This shows that the radiological hazards associated with the use of the granites examined in this study as building material are within the acceptable limit. (authors)

  4. Clay Mineral: Radiological Characterization

    Science.gov (United States)

    Cotomácio, J. G.; Silva, P. S. C.; Mazzilli, B. P.

    2008-08-01

    Since the early days, clays have been used for therapeutic purposes. Nowadays, most minerals applied as anti-inflammatory, pharmaceutics and cosmetic are the clay minerals that are used as the active ingredient or, as the excipient, in formulations. Although their large use, few information is available in literature on the content of the radionuclide concentrations of uranium and thorium natural series and 40K in these clay minerals. The objective of this work is to determine the concentrations of 238U, 232Th, 226Ra, 228Ra, 210Pb and 40K in commercial samples of clay minerals used for pharmaceutical or cosmetic purposes. Two kinds of clays samples were obtained in pharmacies, named green clay and white clay. Measurement for the determination of 238U and 232Th activity concentration was made by alpha spectrometry and gamma spectrometry was used for 226Ra, 228Ra, 210Pb and 40K determination. Some physical-chemical parameters were also determined as organic carbon and pH. The average activity concentration obtained was 906±340 Bq kg-1 for 40K, 40±9 Bq kg-1 for 226Ra, 75±9 Bq kg-1 for 228Ra, 197±38 Bq kg-1 for 210Pb, 51±26 Bq kg-1 for 238U and 55±24 Bq kg-1 for 232Th, considering both kinds of clay.

  5. Preliminary Study of Natural Radioactivity in the Lake Bosumtwi Basin

    Directory of Open Access Journals (Sweden)

    Simon Adu

    2011-08-01

    Full Text Available The concentrations of 238U, 232Th, and 40K in water from Lake Bosumtwi and bore-holes in selected towns around the Bosumtwi basin of the Ashanti region of Ghana have been determined. The concentrations were determined for water samples from 24 boreholes and 12 points across the lake using a High-Purity Germanium (HPGe (γ-ray spectrometry. The water samples from the lake were found to contain acceptable levels of radionuclides with mean activity concentrations of 7.9, 89.7 and 0.6 mBq/L for 238U, 40K, and 232Th, respectively. The water samples from the boreholes recorded mean activity concentrations of 7.7, 85.5, and 3.3 mBq/L for 238U, 40K and 232Th, respectively. The annual effective dose calculated for the lake varied from 0.244 to 1.121 μSv with an average of 0.763 μSv and that calculated for the boreholes varied from 0.296 to 2.173 μSv with an average of 1.166 μSv. The radionuclides concentrations in water from the bore-holes and that of the lake, which serve as sources of water supply to the surrounding communities are negligible and pose no radiological hazards to the public.

  6. Natural radioactivity measurements in Pahang State, Malaysia.

    Science.gov (United States)

    Gabdo, Hamman Tukur; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Garba, Nuraddeen Nasiru; Sanusi, Mohamad

    2016-06-01

    This study was aimed at providing the baseline data of terrestrial gamma dose rates and natural radioactivity to assess the corresponding health risk in the ambient environment of the Pahang State. Terrestrial gamma radiation (TGR) from 640 locations was measured with the mean value found to be 176 ± 5 nGy h(-1). Ninety-eight soil samples were analysed using a high-purity germanium detector (HPGe), and the mean concentrations of the radionuclides (226)Ra, (232)Th and (40)K are 110 ± 3, 151 ± 5 and 542 ± 51 Bq kg(-1), respectively.(226)Ra and (232)Th concentrations were found to be three times the world average, while that of (40)K is quite higher than the world average value. The acid-intrusive geological formation has the highest mean concentrations for (226)Ra (215 ± 6 Bq kg(-1)), (232)Th (384 ± 12 Bq kg(-1)) and (40)K (1564 ± 153 Bq kg(-1)). The radium equivalent activities (Req) and the external hazard index (Hex) for the various soil types were also calculated. Some of the soil types were found to have values exceeding the internationally recommended levels of 370 Bq kg(-1) and the unity value, respectively.

  7. Radioactivity measurements and risk assessments of spa waters in some areas in Turkey.

    Science.gov (United States)

    Duran, Selcen Uzun; Kucukomeroglu, Belgin; Damla, Nevzat; Taskin, Halim; Celik, Necati; Cevik, Uğur; Ersoy, Hakan

    2017-03-01

    The current study presents the results of the activity of radionuclides in spa waters, and evaluates their radiological influences on the population consuming these waters in the Central and Eastern Black Sea regions of Turkey. Since these waters are used for therapy and consumption purposes unconsciously, their radiological impact on the people was computed by taking into consideration the annual intake through ingestion of (226)Ra, (232)Th, (40)K, (137)Cs and (222)Rn. The mean activities were estimated to be 11.35 for gross alpha, 6.23 for gross beta, 2.96 for (226)Ra, 0.42 for (232)Th, 0.069 for (137)Cs, 0.19 for (40)K, and 267 Bq L(-1) for (222)Rn, respectively. The estimated effective doses from spa water were found to be 49.77 µSv a(-1) ((226)Ra), 5.95 µSv a(-1) ((232)Th), 0.07 µSv a(-1) ((137)Cs), 0.83 µSv a(-1) ((40)K) and 56.03 µSv a(-1) ((222)Rn). These values were evaluated and compared with related verified values from literature. Also, physico-chemical characterizations of spa water samples considered in the current study were investigated. This study would be useful for consumers and official authorities for the assessment of radiation exposure risk due to usage of the considered spa waters.

  8. Radioactivity levels and heavy metals in the urban soil of Central Serbia.

    Science.gov (United States)

    Milenkovic, B; Stajic, J M; Gulan, Lj; Zeremski, T; Nikezic, D

    2015-11-01

    Radioactivity concentrations and heavy metal content were measured in soil samples collected from the area of Kragujevac, one of the largest cities in Serbia. The specific activities of (226)Ra, (232)Th, (40)K and (137)Cs in 30 samples were measured by gamma spectrometry using an HPGe semiconductor detector. The average values ± standard deviations were 33.5 ± 8.2, 50.3 ± 10.6, 425.8 ± 75.7 and 40.2 ± 26.3 Bq kg(-1), respectively. The activity concentrations of (226)Ra, (232)Th and (137)Cs have shown normal distribution. The annual effective doses, radium equivalent activities, external hazard indexes and excess lifetime cancer risk were also estimated. A RAD7 device was used for measuring radon exhalation rates from several samples with highest content of (226)Ra. The concentrations of As, Co, Cr, Cu, Mn, Ni, Pb and Zn were measured, as well as their EDTA extractable concentrations. Wide ranges of values were obtained, especially for Cr, Mn, Ni, Pb and Zn. The absence of normal distribution indicates anthropogenic origin of Cr, Ni, Pb and Zn. Correlations between radionuclide activities, heavy metal contents and physicochemical properties of analysed soil were determined by Spearman correlation coefficient. Strong positive correlation between (226)Ra and (232)Th was found.

  9. Radiological study of Mersing District, Johor, Malaysia

    Science.gov (United States)

    Saleh, Muneer Aziz; Ramli, Ahmad Termizi; Alajerami, Yasser; Aliyu, Abubakar Sadiq; Bt Basri, Nor Afifah

    2013-04-01

    A potential site has been selected for a nuclear power plant (NPP) in Mersing District of Malaysia. This study aims at providing the base line data of this district for the first time, in line with the International Atomic Energy Agency (IAEA) for NPP sitting criteria. The mean dose rate, mean population weighted dose rate and annual effective dose are found to be 140 nGy h-1, 0.836 mSv y-1 and 0.857 mSv, respectively. A hyper Purity Germanium Detector (HPGe) is used in determining the activity concentrations of 232Th, 226Ra and 40K. The activity concentration ranges from 16±1 to 410±15 Bq kg-1 for 232Th, 17±1 to 271±8 Bq kg-1 for 226Ra and 13±3 to 1434±57 Bq kg-1 for 40K. In addition, a Low Background Alpha Beta Series 5 XLB Automatic was used in the determination of gross alpha and gross beta activity. The result ranges from 202±50 to 2325±466 Bq kg-1 for gross alpha and 164±17 to 2447±103 Bq kg-1 for gross beta. Contour maps were produced for isodose, activity concentration of 232Th, 226Ra, 40K, gross alpha and gross beta for the study area. The results are compared with UNSCEAR (2000).

  10. Estimation of radioecological parameters of soil samples from a phosphatic area

    Directory of Open Access Journals (Sweden)

    Harb Shaaban

    2016-01-01

    Full Text Available The activity concentrations of natural radionuclides (226Ra, 232Th, and 40K for a set of 31 agricultural soil samples from the Nile River banks in the area of El-Sebaiya city, Aswan Governorate, Egypt were measured by gamma-spectrometry. The study revealed that the average activity concentrations of natural radionuclides 226Ra, 232Th, and 40K were 23.2 ± 2.8Bq/kg, 21.1 ± 2.8 Bq/kg, and 218.6 ± 3.7 Bq/kg, respectively. The obtained results of the activity concentrations are within the range of values reported for neighbouring areas in Egypt. The values obtained for the hazard indices and the representative level index in all sampling sites were lower than unity, showing that there is no significant risk arising from the exposure to the soil in the studied area. The absorbed dose rate and annual effective dose in air outdoors and indoors were calculated from 226Ra, 232Th, and 40K in soil, the average values being 32.64 nGy/h, 40.06 µSv, and 160.25 µSv, respectively. The absorbed dose rate at the eastof El-Sebaiya city is higher than that obtained for the west because of higher concentrations of tri-calcium phosphate in the soil. The studied area is not significantly affected by the industrial activities, except for a few isolated spots.

  11. Releases of natural radionuclides from oil-shale-fired power plants in Estonia

    Energy Technology Data Exchange (ETDEWEB)

    Realo, E.; Realo, K.; Jogi, J. [AN Ehstonskoj SSR, Tartu (Estonia). Inst. Fiziki

    1996-11-01

    In the vicinity of two large oil-shale-fired power plants in northeast Estonia, depth-dependent activity concentrations of natural radionuclides in soil were determined by gamma spectrometry. In the surface soil considerably higher (or lower) concentrations of {sup 40}k, {sup 226}Ra and {sup 232}Th were found than in deeper soil layers. The observed increase or decrease of the enrichment of radionuclides for different sampling sites was dependent on the relative concentrations of radionuclides in fly-ash and in deep soil layers. The fraction of the radionuclides deposited onto the ground was characterized by a mean {sup 226}Ra/{sup 232}Th activity concentration ratio of 2.2, approximately equal to the one (2.1) found for oil-shale filter ash. The atmospheric deposition rates of fly-ash radionuclides onto the ground were estimated and compared to other relevant published data. The migration of the deposited fly-ash radionuclides into soil was satisfactorily described assuming an exponential depth distribution with the relaxation length value, {alpha}{sup -1} = 2.9 {+-} 0.6 cm, for both {sup 226}Ra and {sup 232}Th. (Author).

  12. Characterization of thorium excretion in a region rich in monazite, as subsidy for the analysis of the incorporation in situations of occupational and public exposure; Caracterizacao da excrecao de torio em uma regiao rica em monazita, como subsidio para a analise da incorporacao em situacoes de exposicao ocupacional e de publico

    Energy Technology Data Exchange (ETDEWEB)

    Juliao, Ligia Mendes Quintaes de Castro

    1998-07-01

    The northern part of the state of Rio de Janeiro is characterized by the presence of large deposits of monazite sand In this region a monazite sand extraction plant is located, which has been in operation for more than 20 years In order to analyse the background contribution to the internal contamination, 72 inhabitants of this region were monitored through excreta analysis Some people have contributed with more than one sample to our study In the high background radiation area it was possible to detect significant amounts of {sup 232}Th in urine samples suggesting a chronic thorium incorporation In 'normal' background areas, as in the city of Rio da Janeiro, the amount of {sup 232}Th excreted in urine is not significant. The average {sup 252}Th concentration in feces samples from the non exposed population is about one third of the average of {sup 232}Th concentration in feces samples from the workers and twice of the average concentration in feces samples from inhabitants of the city of Rio de Janeiro The results indicate that the thorium intake is influenced by the place of the residence and show how important is to characterize the region where workers live when an occupational control is done. (author)

  13. Natural Radioactivity in Some Food Crops from Bangka-Belitung Islands, Indonesia

    Directory of Open Access Journals (Sweden)

    Syarbaini

    2014-06-01

    Full Text Available Natural radioactivities of food crops are the main sources of internal radiation exposure in humans. Bangka Belitung islands of Indonesia has natural background radioactivity higher than normal area because of tin mining activities.The study was carried out to evaluate the natural radioactivity concentration in some food crops grown in Bangka and Belitung Islands. Food samples collected from Bangka and Belitung Islands were analysed by means of a gamma spectroscopy for natural radionuclides 226Ra, 232Th and 40K. The annual intake of the food was estimated on the basis of their average annual consumption. Calculations were also made to determine the effective dose to an individual consuming such diets. The intakes of these radionuclides were calculated using the concentrations in Bangka Belitung foods and annual consumption rates of these food. Annual intakes of these radionuclides were as follows: 226Ra= 190.00; 232Th, 633.79 and 40K = 2065.10 Bq/year. The annual internal dose resulting from ingestion of radionuclides in food was 0.205 mSv/year which is very much lower than annual dose limit of 1 mSv for general public. The radionuclides with highest consumption is 40K followed by 232Th and 226Ra

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  15. Radioactivity of sand, groundwater and wild plants in northeast Sinai, Egypt.

    Science.gov (United States)

    Ramadan, Khaled A; Seddeek, Mostafa K; Nijim, Abdelkareem; Sharshar, Taher; Badran, Hussein M

    2011-12-01

    The radioactivity levels are poorly studied in non-coastal arid regions. For this reason, 38 locations covering an area of about 350 km(2) in northeast Sinai, Egypt, were investigated by γ-ray spectroscopy. Moderately significant correlations among (238)U, (234)Th, and (226)Ra isotopes and low significant correlations between the concentrations of (238)U-series and (232)Th in sand were obtained. No evidence of correlation was found between the concentrations of radioisotopes and pH, grain size, total organic matter content, bicarbonate or calcium carbonate concentrations of the sand samples. The mean values of soil-to-plant transfer factor were 0.15, 0.18, 1.52 and 0.74 for (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. The range of concentrations of (226)Ra,( 232)Th, and (40)K in water samples collected from five wells were<0.4-0.16,<0.4-0.13, and<0.15-1.62 Bq l(-1), respectively. The mean absorbed dose rate in outdoor air at a height of 1 m above the ground surface for the sand samples was 19.4 nGy h(-1). The Ra(eq) activities of the sands are lower than the recommended maximum value of 370 Bq kg(-1) criterion limit for building materials.

  16. Measurement of natural radioactivity in building materials used in Urumqi, China.

    Science.gov (United States)

    Ding, Xiang; Lu, Xinwei; Zhao, Caifeng; Yang, Guang; Li, Nan

    2013-07-01

    Building materials contain natural radionuclides (226)Ra, (232)Th and (40)K, which cause direct radiation exposure of the public. The concentrations of (226)Ra, (232)Th and (40)K in commonly used building materials of Urumqi, China have been analysed using gamma-ray spectrometry. The concentrations of (226)Ra, (40)K and (232)Th in the studied building materials range from 19.8 to 87.4, from 273.3 to 981.2 and from 11.6 to 47.7 Bq kg(-1), respectively. The radium equivalent activity (Raeq), gamma index (Iγ) and alpha index (Iα) were calculated to assess the radiation hazards to people living in dwellings made of the materials studied. The calculated Raeq values of all the building materials are lower than the limit of 370 Bq kg(-1) for building materials. The values of Iγ and Iα of all the building materials are less than unity. The study shows that these materials may be safely used as construction materials and do not pose significant radiation hazards.

  17. 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)

  18. Radiological impacts of natural radioactivity from phosphogypsum piles in Huelva (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Duenas, C.; Fernandez, M.C.; Canete, S. [Department of Applied Physics I, Faculty of Science, University of Malaga, 29071 Malaga (Spain); Perez, M., E-mail: mperezm@uma.e [Department of Radiology and Health Physics, Ophthalmology and OTL, Faculty of Medicine, University of Malaga, 29071 Malaga (Spain)

    2010-02-15

    The activity concentrations of {sup 226}Ra, {sup 232}Th and {sup 40}K have been measured by gamma spectroscopy in samples of soil collected from the different zones of around Huelva (Spain). The average activity concentrations of {sup 226}Ra (Bq kg{sup -1}) in the active phosphogypsum (PG) stacks, unrestored and restored zones were 647, 573 and 83 respectively. The corresponding values for {sup 232}Th and {sup 40}K (Bq kg{sup -1}) were 8, 10 and 25 and 33, 47 and 225 respectively. As a measure of radiation hazard to the occupational workers and public, the Ra equivalent activities, representative level index and dose rates due to natural radionuclides at 1 m above the ground surface were estimated. The average of absorbed dose rates due to {sup 226}Ra, {sup 232}Th and {sup 40}K (nGy/h) from active PG stacks, unrestored and restored zones are 284, 255 and 55.The calculated external gamma-radiation average dose (mSv/y) received by the workers of the phosphogypsum piles are estimated to be 0.293, 0.262 and 0.057 which is far below the international agreed dose limit of 20 mSv/y () for workers. Also, the radiation dose to a member of the public resulting from the use of PG is negligible compared to the average annual effective dose from natural sources (2.4 mSv/y).

  19. 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.

  20. Soil depth profiles and radiological assessment of natural radionuclides in forest ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Manigandan, P.K. [Al Musanna College of Technology, Muscat (Oman); Chandar Shekar, B. [Bharathiar Univ., Coimbatore (India). Kongunadu Arts and Science College

    2017-08-01

    We measured the distribution of three naturally occurring radionuclides, {sup 238}U, {sup 232}Th, and {sup 40}K, in soil samples collected from a rainforest in the Western Ghats of India. For each surface sample, we calculated average activity concentration, outdoor terrestrial γ dose rate, annual effective dose equivalent (AEDE), and radiation hazard index. The activity concentrations of surface samples were randomly distributed over space, but differed slightly with different soil depths. The concentration of {sup 232}Th and the average terrestrial γ dose rates were slightly higher than the world averages, so slightly high γ radiation appears to be a general characteristic of the Western Ghats. However, all radiological hazard indices were within the limits proposed by the International Commission on Radiological Protection. The results reported here indicate that, except for {sup 232}Th, the naturally occurring radionuclides in the forest soils of the Western Ghats were within the ranges specified by United Nations Scientific Committee on the Effects of Atomic Radiation for undisturbed virgin soils.

  1. Analytical evaluation of natural radionuclides and their radioactive equilibrium in raw materials and by-products.

    Science.gov (United States)

    Ji, Young-Yong; Chung, Kun Ho; Lim, Jong-Myoung; Kim, Chang-Jong; Jang, Mee; Kang, Mun Ja; Park, Sang Tae

    2015-03-01

    An investigation into the distribution of natural radionuclides and radioactive secular equilibrium in raw materials and by-products in a domestic distribution was conducted to deduce the optimum conditions for the analytical evaluation of natural radionuclides for (238)U, (226)Ra, and (232)Th using a gamma-ray spectrometer and inductively coupled plasma mass spectrometer (ICP-MS). The range of the specific activities of natural radionuclides was first evaluated by analyzing (228)Ac and (214)Bi, which are (232)Th and (226)Ra indicators, respectively, in about 100 samples of raw materials and by-products through a gamma-ray spectrometer. From further experiments using several samples selected based on the results of the distribution of natural radionuclides, the validation of their analytical evaluations for the indirect measurements using a gamma-ray spectrometer and direct measurements using ICP-MS was assured by comparing their results. Chemically processed products from the raw materials, such as Zr sand and ceramic balls, were generally shown for the type of bead and particularly analyzed showing a definite disequilibrium with above a 50% difference between (238)U and (226)Ra in the uranium series and (232)Th and (228)Ra in the thorium series. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Implications of modelled radioactivity measurements along coastal Odisha, Eastern India for heavy mineral resources

    Science.gov (United States)

    Ghosal, S.; Agrahari, S.; Guin, R.; Sengupta, D.

    2017-01-01

    A radioelemental assemblage assessment of two beaches of Odisha is performed for the first time. The radiation is measured in two ways, both on field with the help of a hand held environmental survey meter and in the laboratory, where the concentrations of radionuclide's 238U, 232Th and 4K have been determined with the help of High Purity Germanium detector (HPGe). Mineralogical analysis of selected samples has been performed with the help of X-Ray Fluorescence Spectrometry (XRF). A marked difference between the concentration of Uranium (274 Bq kg-1) and Thorium (2489 Bq kg-1) is observed and discussed based on the geology of the area. The placer deposits showing an enrichment of thorium can be an important source of nuclear fuel for the thorium based nuclear reactors. The ratio of thorium and uranium concentrations gives us an idea about the coastal processes associated with the beach. Statistical analysis of the data shows a positive correlation between 238U and 232Th and a strong negative correlation is indicated between 4 K and 238U, 232Th. A cross plot between the equivalent thorium and the equivalent uranium and the equivalent thorium and potassium, represents the nature of deposition and its association with the heavy mineral along with the radioactive elements. Heavy minerals exhibit an increasing trend towards Northeast-Southwest along the south eastern coast of India.

  3. Determination of uranium, thorium and potassium activity concentrations in soil cores in Araba valley, Jordan.

    Science.gov (United States)

    Abusini, M; Al-Ayasreh, K; Al-Jundi, J

    2008-01-01

    Soil samples were collected from six different locations in Araba valley, situated between Aqaba port and Dead sea. The samples have been analysed by using gamma-ray spectrometry. From the measured gamma-ray spectra, activity concentrations are determined for (238)U, (232)Th and (40)K. The mean activity concentration for (238)U, (232)Th and (40)K was found to be in the range 19 +/- 1.4 to 38.7 +/- 3, 14.3 +/- 0.8 to 35 +/- 3.2 and 94 +/- 18.9 to 762 +/- 47.4 Bq kg(-1), respectively. These results indicate that the mean concentrations of (238)U, (232)Th and (40)K in the populated Araba valley are lower than those in other populated areas. On the other hand, the concentrations of the major oxides (Al(2)O(3), SiO(2), K(2)O, CaO and Fe(2)O(3)) in the samples were determined using wavelength dispersive X-ray fluorescence. High potassium and iron content in some samples might be attributed to the active faults, which refer to the Dead sea transform fault.

  4. Geochemistry of uranium and thorium and natural radioactivity levels of the western Anatolian plutons, Turkey

    Science.gov (United States)

    Papadopoulos, Argyrios; Altunkaynak, Şafak; Koroneos, Antonios; Ünal, Alp; Kamaci, Ömer

    2017-01-01

    Seventy samples from major plutons (mainly granitic) of Western Anatolia (Turkey) have been analyzed by γ-ray spectrometry to determine the specific activities of 238U, 226Ra, 232Th and 40K (Bq/kg). Τhe natural radioactivity ranged up to 264 Bq/kg for 238U, 229.62 Bq/kg for 226Ra, up to 207.32 Bq/kg for 232Th and up to 2541.95 Bq/kg for 40K. Any possible relationship between the specific activities of 226Ra, 238U, 232Th and 40K and some characteristics of the studied samples (age, rock-type, colour, grain size, occurrence, chemical and mineralogical composition) was investigated. Age, major and trace element geochemistry, color, pluton location and mineralogical composition are likely to affect the concentrations of the measured radionuclides. The range of the Th/U ratio was large (0.003-11.374). The latter, along with 226Ra/238U radioactive secular disequilibrium, is also discussed and explained by magmatic processes during differentiation.

  5. ASSESSMENT OF AGE-DEPENDENT RADIATION DOSE DUE TO INTAKE OF URANIUM AND THORIUM IN DRINKING WATER FROM SIKAR DISTRICT, RAJASTHAN, INDIA.

    Science.gov (United States)

    Duggal, Vikas; Rani, Asha; Balaram, V

    2016-10-01

    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. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Basin-Scale nd Isotope Gradients in South Atlantic Marine Sedimentary Records

    Science.gov (United States)

    Ran, W.; Abouchami, W.; Zahn, R.; Masque, P.

    2012-12-01

    Recent 231Pa/230Th and Nd isotopes studies have suggested a slower and re-configured Meridional Overturning Circulation in the Atlantic (AMOC) during the Last Glacial Maximum (LGM) [1]. We have undertaken a Sr and Nd isotope study on sediment core MD02-2594 (34°43'S, 17°20'E, 2440 m) located in the Cape Basin where nutrient-based proxies - δ13C and Cd/Ca ratios - and low 231Pa/230Th, a tracer of deep water overturning rate, indicate the presence of Southern Component Water (SCW) and a weaker AMOC during the LGM [1]. Samples cover the LGM and Holocene sections of the core previously analysed for Pa/Th [1]. Sr and Nd isotope data were obtained on the bulk sediment as well as on the Fe-Mn oxides leachates and the residual detrital fraction extracted using established sequential leaching procedure. Analyses were performed on a ThermoFisher Triton TIMS at MPIC and Nd isotopes measured as NdO. Our results show that the bulk sediment Nd isotope record is, as expected, overprinted by the Nd isotope composition of the lithogenic fraction and follows closely the 231Pa/230Th record. Sr isotope ratios in Fe-Mn leachates have been used as diagnostic of a seawater origin for the Fe-Mn oxides which should yield modern seawater Sr isotopic composition. Our samples have 87Sr/86Sr ratios similar to or slightly higher than those measured for seawater [2]. The Nd isotope composition of the Fe-Mn leachates show, nevertheless, a distinct signature from both the bulk sediment and the detrital fraction, both of which display systematically less radiogenic Nd isotope ratios throughout the whole record. The seawater ɛNd record exhibits a decreasing trend from the LGM into the Bolling-Allerød and Younger Dryas, prior to stabilizing at a value of about -9 during the Holocene. Covariations between Nd isotope ratios of Fe-Mn leachates and 231Pa/230Th reveal contrasted behaviour during the LGM and the Holocene period: low and nearly constant glacial Pa/Th values are associated with

  7. Current activities and future plans for nuclear data measurements at J-PARC

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Atsushi; Harada, Hideo; Nakamura, Shoji; Iwamoto, Osamu; Toh, Yosuke; Koizumi, Mitsuo; Kitatani, Fumito; Furutaka, Kazuyoshi [Japan Atomic Energy Agency, Ibaraki (Japan); Igashira, Masayuki; Katabuchi, Tatsuya; Mizumoto, Motoharu [Tokyo Institute of Technology, Research Laboratory for Nuclear Reactors, Tokyo (Japan); Hori, Jun-ichi [Kyoto University, Research Reactor Institute, Osaka (Japan); Kino, Koichi [Hokkaido University, Faculty of Engineering, Sapporo (Japan); Kiyanagi, Yoshiaki [Nagoya University, Graduate School of Engineering, Nagoya (Japan)

    2015-12-15

    In order to improve the data accuracy of neutron-capture cross-sections of minor actinides (MAs) and long-lived fission products (LLFPs), a new experimental instrument named ''Accurate Neutron-Nucleus Reaction measurement Instrument'' (ANNRI) has been constructed in the Materials and Life science experimental Facility (MLF) at the Japan Proton Accelerator Research Complex (J-PARC), and measurements of neutron-capture cross-sections of MAs, LLFPs and some stable isotopes with high-intensity pulsed neutrons have been started. The analyses for {sup 244}Cm, {sup 246}Cm, {sup 241}Am and {sup 237}Np were finished; those for {sup 129}I, {sup 107}Pd, {sup 99}Tc, {sup 93}Zr and some stable isotopes are in progress. These results will give significant contributions in the field of developing innovative nuclear systems. (orig.)

  8. Measurements of fast neutron-induced fission data of Np-237

    Energy Technology Data Exchange (ETDEWEB)

    Win, Than; Saito, Keiichiro; Baba, Mamoru; Iwasaki, Tomohiko; Ibaraki, Masanobu; Miura, Takako; Sanami, Toshiya; Nauchi, Yasushi; Hirakawa, Naohiro [Tohoku Univ., Sendai (Japan). Faculty of Engineering

    1998-03-01

    We have performed the following measurements for {sup 237}Np using the 4.5 MV Dynamitron accelerator of Tohoku University as the pulsed neutron source: (1) Prompt fission neutron spectrum for 0.62 MeV incident neutrons, and (2) Neutron-Induced fission cross-section between 10 and 100 keV. The prompt fission neutron spectrum was measured using TOF method with a heavily shielded NE213 scintillation detector. The Maxwellian temperature T{sub m} derived is 1.28 MeV, which is lower than that of 1.38 MeV in JENDL-3.2. The fission cross sections were measured between 10 - 100 keV. The results are between JENDL-3.2 and ENDF/B-VI. (author)

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

    Directory of Open Access Journals (Sweden)

    Ducasse Q.

    2013-12-01

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

  10. Improved Neutron Capture Cross Section Measurements with the n_TOF Total Absorption Calorimeter

    CERN Document Server

    Mendoza, E; Perkowski, J; Andriamonje, S; Carrapico, C; Moinul, M; Vannini, G; Quesada, J M; Harrisopulos, S; Milazzo, P M; Berthier, B; Lozano, M; Krticka, M; Domingo-Pardo, C; Nolte, R; Chiaveri, E; Saarmento, H; Jericha, E; Ferrari, A; Massimi, C; Giubrone, G; Avrigeanu, V; Martinez, T; Guerrero, C; Andrzejewski, J; Karadimos, D; Mengoni, A; Ganesan, S; Vlachoudis, V; Becares, V; Cortes, G; Variale, V; Losito, H; Calvino, F; Kappeler, F; Gunsing, F; Gramegna, F; Colonna, N; Marrone, S; Pavlik, A; Berthoumieux, E; Paradela, C; Mastinu, P F; Vaz, P; Tassan-Got, L; Kadi, Y; Tarrio, D; Cano-Ott, D; Brugger, M; Wallner, A; Audouin, L; Fernandez-Ordonez, M; Becvar, F; Goncalves, I F; Cerutti, F; Ventura, A; Mosconi, M; Tagliente, G; Duran, I; Casado, A; Ioannides, K; Weiss, C; Mirea, M; Gomez-Hornillos, M B; Vlastou, R; Calviani, M; Lederer, C; Gonzalez-Romero, E; Marganiec, J; Vidriales, J J; Lebbos, E; Leeb, H; Heil, M; Dillmann, I; Tain, J L; Belloni, F

    2011-01-01

    The n\\_TOF collaboration operates a Total Absorption Calorimeter (TAC) {[}1] for measuring neutron capture cross-sections of low-mass and/or radioactive samples. The results obtained with the TAC have led to a substantial improvement of the capture cross sections of (237)Np and (240)Pu {[}2]. The experience acquired during the first measurements has allowed us to optimize the performance of the TAC and to improve the capture signal to background ratio, thus opening the way to more complex and demanding measurements on rare radioactive materials. The new design has been reached by a series of detailed Monte Carlo simulations of complete experiments and dedicated test measurements. The new capture setup will be presented and the main achievements highlighted.

  11. Speciation of long-lived radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Xiaolin Hou

    2008-11-15

    This project started in November 2005 and ended in November 2008, the work and research approaches are summarized in this report. This project studied the speciation of radionuclides in environment. A number of speciation analytical methods are developed for determination of species of 129I, 99Tc, isotopes of Pu, and 237Np in seawater, fresh water, soil, sediment, vegetations, and concrete. The developed methods are used for the investigation of the chemical speciation of these radionuclides as well as their environmental behaviours, especially in Danish environment. In addition the speciation of Pu isotopes in waste samples from the decommissioning of Danish nuclear facilities is also investigated. The report summarizes these works completed in this project. Through this research project, a number of research papers have been published in the scientific journals, the research results has also been presented in the Nordic and international conference/meeting and communicated to international colleagues. Some publications are also enclosed to this report. (au)

  12. Fast data acquisition in Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kalvius, G.M. (Technische Universitaet Muenchen, Garching, Ger.); Potzel, W.; Koch, W.; Forster, A.; Asch, L.; Wagner, F.E.; Halder, N.

    1977-01-01

    Three different gamma-ray detection systems for Moessbauer measurements at count rates above 10/sup 5/ s/sup -1/ are described. The first uses the fast output of an uncooled NaI(Tl) scintillation counter and will still provide energy discrimination at total pulse rates up to 10/sup 6/ s/sup -1/. Count rates up to some 10/sup 7/ s/sup -1/ can be handled by a tin-loaded plastic scintillation detector, but only with very limited energy resolution. For even higher photon intensities, the method of current integration is available. The various techniques are illustrated and compared on the basis of measurements with the Moessbauer resonances in /sup 170/Yb (84 keV), /sup 199/Hg (158 keV) and /sup 237/Np (60 keV).

  13. Pressure-dependent hyperfine interactions in NpAl/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Litterst, F.J.; Moser, J.; Potzel, W.; Potzel, U.; Kalvius, G.M.; Asch, L.; Gal, J.; Spirlet, J.C.

    1986-12-01

    /sup 237/Np Moessbauer data of NpAl/sub 2/ are reported for pressures up to 90 kbar in a temperature range from 1.5 K to 77 K. Application of pressure yields a continuous reduction of the Curie temperature T/sub c/, of the saturation hyperfine magnetic field and of the isomer shift indicating an increasing delocalization of 5 f electrons. Severe relaxational broadenings of the magnetic patterns are found especially for high pressures and close to T/sub c/. In part these may be connected with interconfigurational fluctuations but major role play fluctuations within the lowest electronic levels of Np at rates in the range of 1-10 GHz.

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

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Steier, Peter;

    2013-01-01

    An automated analytical method implemented in a novel dual-column tandem sequential injection (SI) system was developed for simultaneous determination of 236U, 237Np, 239Pu, and 240Pu in seawater samples. A combination of TEVA and UTEVA extraction chromatography was exploited to separate and purify...... target analytes, whereupon plutonium and neptunium were simultaneously isolated and purified on TEVA, while uranium was collected on UTEVA. The separation behavior of U, Np, and Pu on TEVA–UTEVA columns was investigated in detail in order to achieve high chemical yields and complete purification...... for the radionuclides of interest. 242Pu was used as a chemical yield tracer for both plutonium and neptunium. 238U was quantified in the sample before the separation for deducing the 236U concentration from the measured 236U/238U atomic ratio in the separated uranium target using accelerator mass spectrometry...

  15. The simultaneous neutron and photon interrogation method for fissile and non-fissile element separation in radioactive waste drums

    Energy Technology Data Exchange (ETDEWEB)

    Jallu, F. E-mail: fanny.jallu@cea.fr; Lyoussi, A.; Passard, C.; Payan, E.; Recroix, H.; Nurdin, G.; Buisson, A.; Allano, J

    2000-10-01

    Measuring {alpha}-emitters such as ({sup 234,235,236,238}U, {sup 238,239,240,242,244}Pu, {sup 237}Np, {sup 241,243}Am, ...), in solid radioactive waste allows us to quantify the {alpha}-activity in a drum and then to classify it. The simultaneous photon and neutron interrogation experiment (SIMPHONIE) method dealt with in this paper, combines both active neutron interrogation and induced photofission interrogation techniques simultaneously. Its purpose is to quantify fissile ({sup 235}U, {sup 239,241}Pu, ...) and non-fissile ({sup 236,238}U, {sup 238,240}Pu, ...) elements separately in only one measurement. This paper presents the principle of the method, the experimental setup, and the first experimental results obtained using the DGA/ETCA Linac and MiniLinatron pulsed linear electron accelerators located at Arcueil, France. First studies were carried out with U and Pu bare samples.

  16. Determination of spatial and energy distributions of neutrons in experiments on transmutation of radioactive waste using relativistic protons

    Energy Technology Data Exchange (ETDEWEB)

    Zhuk, I.V.; Lomonosova, E.M.; Boulyga, S.F.; Kievitskaia, A.I.; Rakhno, I.L.; Chigrinov, S.E.; Bradnova, V.; Krivopustov, M.I.; Kulakov, B.A.; Brandt, R.; Ochs, M.; Wan, J.-S

    1999-06-01

    The experiments on transmutation of {sup 129}I and {sup 237}Np using uranium-lead targets surrounded by a paraffin moderator were performed at the Joint Institute for Nuclear Research (JINR, Russia). The targets were irradiated by 1.5 GeV and 7.4 GeV protons at the Synchrophasotron of JINR. In the frame of present work spatial and energy distributions of neutrons on the surface of the paraffin moderator were measured using SSNTD technique. It is shown that measured values of spectral indices do not depend on the energy of incident protons but depend on the target composition. The presence of the uranium insertion softens neutron spectra.

  17. National Low-Level Waste Management Program Radionuclide Report Series

    Energy Technology Data Exchange (ETDEWEB)

    J.P. Adams; M.L. Carboneau; W.E. Allred

    1999-02-01

    The National Low Level Waste Management Program at the Idaho National Engineering and Environmental Laboratory has published a report containing key information about selected radionuclides that are most likely to contribute significantly to the radiation exposures estimated from a performance assessment of a low-level radioactive waste (LLW) disposal facility. The information includes physical and chemical characteristics, production means, waste forms, behavior of the radionuclide in soils, plants, groundwater, and air, and biological effects in animals and humans. The radionuclides included in this study comprise all of the nuclides specifically listed in 10CFR61.55, Tables 1 and 2, 3 H, 14 C, 59 Ni, 60 Co, 63 Ni, 90 Sr, 94 Nb, 99 Tc, 129 I, 137 Cs, 241 Pu, and 242 Cm. Other key radionuclides addressed in the report include 237 Np, 238 U, 239 Pu, and 241 Am. This paper summarizes key information contained within this report.

  18. National Low-Level Waste Management Program Radionuclide Report Series

    Energy Technology Data Exchange (ETDEWEB)

    Adams, James Paul; Carboneau, Michael Leonard; Allred, William Edgar

    1999-03-01

    The National Low Level Waste Management Program at the Idaho National Engineering and Environmental Laboratory has published a report containing key information about selected radionuclides that are most likely to contribute significantly to the radiation exposures estimated from a performance assessment of a low-level radioactive waste (LLW) disposal facility. The information includes physical and chemical characteristics, production means, waste forms, behavior of the radionuclide in soils, plants, groundwater, and air, and biological effects in animals and humans. The radionuclides included in this study comprise all of the nuclides specifically listed in 10CFR61.55, Tables 1 and 2, 3 H, 14 C, 59 Ni, 60 Co, 63 Ni, 90 Sr, 94 Nb, 99 Tc, 129 I, 137 Cs, 241 Pu, and 242 Cm. Other key radionuclides addressed in the report include 237 Np, 238 U, 239 Pu, and 241 Am. This paper summarizes key information contained within this report.

  19. Intermediate mass fragment production in the proton-induced reactions of heavy targets

    CERN Document Server

    Deppman, A; Guimaraes, V; Karapetyan, G S; Balabekyan, A R; Demekhina, N A; Adam, J

    2013-01-01

    The production of intermediate-mass fragments (IMFs) formed in the proton-induced reaction with $^{238}$U and $^{237}$Np at 660 MeV was measured in the LNP Phasotron and in U-400M Cyclotron, Joint Institute for Nuclear Research (JINR), Dubna, Russia. We have applied the induced-activation method in off-line analysis. A total of 115 isotopes of all elements in the range $7 \\leq A \\leq 69$ were unambiguously identified with high precision. There is a consideration that the formed nuclides could be produced in a very asymmetric binary decay of heavy nuclei originating from the spallation of heavy targets. Mass-yield distributions were derived from the data, and were compared with the the simulation code CRISP for multi modal fission.

  20. Transmutation studies using SSNTD and radiochemistry and the associated production of secondary neutrons

    CERN Document Server

    Brandt, R; Wan, J S; Schmidt, T; Langrock, E J; Vater, P; Adam, J; Bamblevski, V P; Bradnova, V; Gelovani, L K; Kalinnikov, V K; Krivopustov, M I; Kulakov, B A; Sosnin, A N; Perelygin, V P; Pronskikh, V S; Stegailov, V I; Tsoupko-Sitnikov, V M; Modolo, G; Odoj, R; Philippen, P W; Adloff, J C; Pape, F; Debeauvais, M; Zamani-Valassiadou, M; Hashemi-Nezhad, S R; Dwivedi, K K; Guo Shi Lun; Li, L; Wang, Y L; Wilson, B

    1999-01-01

    Experiments using 1.5 GeV, 3.7 GeV and 7.4 GeV protons from the Synchrophasotron, LHE, JINR, Dubna, Russia, on extended Pb- and U- targets were carried out using SSNTD and radiochemical sensors for the study of secondary neutron $9 fluences. We also carried out first transmutation studies on the long-lived radwaste nuclei /sup 129/I and /sup 237/Np. In addition, we carried out computer code simulation studies on these systems using LAHET and DCM/CEM codes. We $9 have difficulties to understand rather large transmutation rates observed experimentally when they are compared with computer simulations. There seems to be a rather fundamental problem understanding the large transmutation rates as $9 observed experimentally in Dubna and CERN, as compared to those theoretical computer simulations mentioned above. (10 refs).

  1. Level density and gamma-ray strength function in the odd-odd 238Np

    CERN Document Server

    Tornyi, Tamás Gábor; Eriksen, Tomas Kvalheim; Görgen, Andreas; Giacoppo, Francesca; Hagen, Trine Wiborg; Krasznahorkay, Attila; Larsen, Ann-Cecilie; Renstrøm, Therese; Rose, Sunniva Johanne; Siem, Sunniva; Tveten, Gry Merete

    2014-01-01

    The level density and gamma-ray strength function in the quasi-continuum of 238Np has been measured using the Oslo method. The level density function follows closely the constant-temperature level density formula and reaches 43 million levels per MeV at Sn = 5.488 MeV of excitation energy. The gamma-ray strength function displays a two-humped resonance at low-energy as also seen in previous investigations of Th, Pa and U isotopes. The structure is interpreted as the scissors resonance and has an average centroid of wSR = 2.26(5) MeV and a total strength of BSR = 10.8(12)m2N, which is in excellent agreement with sum-rule estimates. The scissors resonance is shown to have an impact on the 237Np(n; g)238Np cross section.

  2. Measurements of the neutron capture cross sections and incineration potentials of minor-actinides in high thermal neutron fluxes: Impact on the transmutation of nuclear wastes; Mesures des sections efficaces de capture et potentiels d'incineration des actinides mineurs dans les hauts flux de neutrons: Impact sur la transmutation des dechets

    Energy Technology Data Exchange (ETDEWEB)

    Bringer, O

    2007-10-15

    This thesis comes within the framework of minor-actinide nuclear transmutation studies. First of all, we have evaluated the impact of minor actinide nuclear data uncertainties within the cases of {sup 241}Am and {sup 237}Np incineration in three different reactor spectra: EFR (fast), GT-MHR (epithermal) and HI-HWR (thermal). The nuclear parameters which give the highest uncertainties were thus highlighted. As a result of fact, we have tried to reduce data uncertainties, in the thermal energy region, for one part of them through experimental campaigns in the moderated high intensity neutron fluxes of ILL reactor (Grenoble). These measurements were focused onto the incineration and transmutation of the americium-241, the curium-244 and the californium-249 isotopes. Finally, the values of 12 different cross sections and the {sup 241}Am isomeric branching ratio were precisely measured at thermal energy point. (author)

  3. Study on the properties of saline HLLW in China

    Institute of Scientific and Technical Information of China (English)

    LiangJun-Fu; TianGuo-Xing; 等

    1997-01-01

    The properties and the component of HLLW(High Level Liquid Waste)were studied.The senuine saline HLLW is a blue-green liquid without any deposition.Its density and acidity are 1.399 g/ml(23±1℃) and 2.1 mol/L NHO3,respectively.The activities of 137Cs, 90Sr,99Tc,237Np,239Pu,241Am,total α,totalβ,totalγ are determined.The extractabilities of actinides in the genuine HLLW were examined with a five-stage cross extraction experiment.More than 98% of Pu is in Pu4+ species,and more than 70% of Np is in Np4+ species.More than 99.97% α-nuclides could be extracted by 30% TRPO-Kerosene in 1mol/L NHO3 from the HLLW.

  4. Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples.

    Science.gov (United States)

    Hou, Xiaolin; Roos, Per

    2008-02-11

    The radiometric methods, alpha (alpha)-, beta (beta)-, gamma (gamma)-spectrometry, and mass spectrometric methods, inductively coupled plasma mass spectrometry, accelerator mass spectrometry, thermal ionization mass spectrometry, resonance ionization mass spectrometry, secondary ion mass spectrometry, and glow discharge mass spectrometry are reviewed for the determination of radionuclides. These methods are critically compared for the determination of long-lived radionuclides important for radiation protection, decommissioning of nuclear facilities, repository of nuclear waste, tracer application in the environmental and biological researches, these radionuclides include (3)H, (14)C, (36)Cl, (41)Ca, (59,63)Ni, (89,90)Sr, (99)Tc, (129)I, (135,137)Cs, (210)Pb, (226,228)Ra, (237)Np, (241)Am, and isotopes of thorium, uranium and plutonium. The application of on-line methods (flow injection/sequential injection) for separation of radionuclides and automated determination of radionuclides is also discussed.

  5. Leaching tests of simulated Cogema bituminized waste form

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, S.; Akimoto, T.; Iida, Y.; Nagano, T. [Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

    2000-07-01

    The leaching behavior of COGEMA-type bituminized radioactive waste was studied for the atmospheric and anaerobic conditions. Active and inactive laboratory-scale bitumen samples, including two major salts of NaNO{sub 3} and BaSO{sub 4}, were contacted with deionized water, an alkaline solution (0.01 mol/L Ca(OH){sub 2} or 0.03 mol/L KOH), or a saline solution (0.5 mol/L KCl). It was found that the release of salt was reduced in the Ca(OH){sub 2} solution compared with deionized water under the atmospheric conditions. No significant difference in the concentrations of {sup 237}Np in leachants contacted with the samples for 7 days was observed between the atmospheric and the anaerobic conditions. (authors)

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

    Directory of Open Access Journals (Sweden)

    Tveten G. M.

    2013-03-01

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

  7. Some results from the second iteration of total-system performance assessment for Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, M.L. [Sandia National Labs., Albuquerque, NM (United States)

    1994-12-31

    The second preliminary total-system performance assessment for the potential radioactive-waste-repository site at Yucca Mountain has recently been completed. This paper summarizes results for nominal aqueous and gaseous releases using the composite-porosity flow model. The results are found to be sensitive to the type of unsaturated-zone flow, to percolation flux and climate change, to saturated-zone dilution, to container-wetting processes and container-corrosion processes, to fuel-matrix alteration rate and radionuclide solubilities (especially for {sup 237}Np), and to bulk permeability and retardation of gases {sup 14}C. There are areas that should be given priority in the site-characterization program. Specific recommendations are given in the full report of the study.

  8. Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results

    Energy Technology Data Exchange (ETDEWEB)

    Coles, D.G.

    1981-08-20

    A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for /sup 237/Np and /sup 239/Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected the leach rate, but only slightly. Temperature effects were significant. Plutonium leach rate was lower at higher temperature suggesting that Pu sorption onto the beads was enhanced at the higher temperature. The range of leach rates for all analyzed elements (except Pu), at both temperatures, at all three flow rates, and with all three leachant compositions varied over only three orders of magnitude. The range of variables used in this experiment covered those expected in many proposed repository environments.

  9. 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.)

  10. U-Th-Ra variations in Himalayan river sediments (Gandak river, India): Weathering fractionation and/or grain-size sorting?

    Science.gov (United States)

    Bosia, Clio; Chabaux, François; Pelt, Eric; France-Lanord, Christian; Morin, Guillaume; Lavé, Jérôme; Stille, Peter

    2016-11-01

    Understanding the origin of U-Th-Ra variations in the Ganga river sediments is a prerequisite for correctly using U-series nuclides to constrain the sediment transport times in Himalayan rivers. For this purpose, U, Th, and Ra concentrations, along with 238U-234U-230Th-226Ra radioactive disequilibria, were analyzed in bank, bedload and suspended sediments from the Gandak river, one of the main tributaries of the Ganga river. The data confirm that U and Th budgets of the Himalayan sediments are significantly influenced by minor resistant minerals, such as zircon, garnet and Ti-bearing minerals, the dissolution of which required the use of a high-pressure acid digestion process. Most importantly, the results indicate that the variations in (238U/232Th) and (230Th/232Th) activity ratios and 238U-234U-230Th-226Ra disequilibria in sediments along the river alluvial plain mainly reflect modifications in the mineralogical and grain-size compositions rather than the degree of weathering during transport. The (238U/232Th) and (230Th/232Th) activity ratios in the bank and bed sediments are related to variations in the minor primary minerals strongly enriched in U and Th (i.e., zircon, REE-bearing minerals and Ti-bearing minerals), whereas the activity ratios in the suspended load are related to variations in the proportions of clay, Fe-oxyhydroxides and the silt-sand fraction, which contains U- and Th-bearing minor minerals. The data also indicate that 238U-234U-230Th-226Ra disequilibria are strongly influenced by secondary mineral phases: the 230Th budget is likely mainly controlled by Fe-oxyhydroxides, and the 226Ra budget is likely mainly controlled by clay minerals. Therefore, the variations in the 238U-234U-230Th-232Th system in the sediments of the Gandak river cannot simply be interpreted as the result of fractionation due to chemical transformation of the bulk sediment during its transport within the alluvial plain and/or the result of radioactive decay. Consequently

  11. 武汉市空气中~(238)U、~(226)Ra、~(232)Th放射性浓度估算

    Institute of Scientific and Technical Information of China (English)

    施锦华; 陈昌华

    1989-01-01

    本文报道武汉市空气中~(238)U、~(226)Ra、~(232)Th 放射性浓度的估算结果。空气中~(238)U、~(226)Ra、~(232)Th 的放射性浓度是根据地面空气中铀、镭、钍的主要天然来源是土壤粒子的再悬浮的假定,通过调查测量武汉市土壤中天然放射性核素含量和空气中含尘量,经计算后确定的。我们于1984年4—10月在武汉地区采集了60个土壤样品,调查测量了土壤中天然放射性核素含量,并根据在1981—1985年间采集的7346个空气粉尘样品测得的空气中含尘量,估算出武汉市空气中~(238)U、~(226)Ra 和~(232)Th 放射性浓度的五年平均值分别为24.0、18.9和28.7nBq/L。五年中以1983年的平均值最高,分别为30.4、23.9和36.2nBq/L。以1984和1985年的数据为例,空气中~(238)U、(226)Ra、~(232)Th 放射性浓度呈明显的季节性变化,两年中均以冬季为最高,夏季最低。在武汉市六个城区中,空气中~(238)U、~(226)Ra、~(232)Th 的放射性浓度,以青山区最高,武昌区最低。

  12. Determination of thorium isotopes in mineral and environmental water and soil samples by alpha-spectrometry and the fate of thorium in water.

    Science.gov (United States)

    Jia, Guogang; Torri, G; Ocone, R; Di Lullo, A; De Angelis, A; Boschetto, R

    2008-10-01

    A method has been developed for determination of thorium isotopes in water and soil samples by alpha-spectrometry. After fusion with Na(2)CO(3) and Na(2)O(2) at 600 degrees C, soil samples were leached with HNO(3) and HCl. Thorium in water sample or in soil leaching solution was coprecipitated together with iron (III) as hydroxides and/or carbonates at pH 9 with ammonia solution, separated from uranium and other alpha-emitters by a Microthene-TOPO (tri-octyl-phosphine oxide) chromatographic column, electrodeposited on a stainless steel disk, and measured by alpha-spectrometry. The method was checked with two certified reference materials supplied by the IAEA, and reliable results were obtained. The detection limits of the method for water (soil) samples are 0.44 microBq l(-1) (0.070 Bq kg(-1)) for (232)Th, 0.80 microBq l(-1) (0.13 Bq kg(-1)) for (230)Th and 1.0 microBq l(-1) (0.16 Bq kg(-1)) for (228)Th, respectively, if 100 l of water (0.50 g) for each sample are analysed. A variety of water or soil samples were analysed using this procedure and giving average thorium yields of 75.5+/-14.2% for water and 93.4+/-4.5% for soil. The obtained concentrations of thorium isotopes in water samples are in the range of 0.0007-0.0326 mBq l(-1) for (232)Th, thorium isotopes in water was studied. The exposure impact due to intake of thorium in the analysed drinking water was evaluated, showing a negligible amount of dose contribution. The concentrations of (232)Th, (230)Th and (228)Th in the analysed soil samples are in the range of 30.2-48.6, 32.5-60.5 and 31.0-53.0 Bq kg(-1), respectively. The obtained mean ratio is 1.04+/-0.05 for (228)Th/(232)Th and 1.20+/-0.41 for (230)Th/(232)Th.

  13. Neptunium(V) sorption behavior on clinoptilolite, quartz and montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Bertetti, F.P.; Pabalan, R.T.; Turner, D.R.; Almendarez, M.G. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

    1996-08-01

    Performance assessment models have identified {sup 237}Np as a radionuclide of concern in meeting release limits established for the geologic disposal of high-level nuclear waste at the proposed repository at Yucca Mountain, Nevada. In this study, quartz, clinoptilolite, and montmorillonite, which are minerals representative of phases that occur both in the rock matrix and as fracture coatings at Yucca Mountain, were reacted with {sup 237}Np-bearing solutions to characterize the sorption behavior of Np(V) on these minerals. Batch experiments were conducted over a wide range of conditions in which pH of solution, surface loading, sorbent surface area, initial concentration of Np(V), and partial pressure of CO{sub 2} were varied. Initial Np(V) concentrations were between 1 {times} 10{sup {minus}7} and 1 {times} 10{sup {minus}6} M in electrolyte solutions of 0.1 or 0.01 M NaNO{sub 3}. The oxidation state of Np in solution was verified with NIR spectroscopy and by solvent extraction. Prior to the start of experiments, minerals were pretreated to eliminate impurities, and the clinoptilolite and montmorillonite were converted to Na-form by ion exchange with NaCl solutions. Results indicate that, for all three minerals, Np(V) sorption begins at pH values coincident with the start of hydrolysis in solution ({approximately}7). For solutions undersaturated with respect to atmospheric CO{sub 2}, sorption increases continuously with increasing pH. Under equilibrium with atmospheric CO{sub 2}, Np(V) sorption is important in the pH range (7--9.5) where NpO{sub 2}(OH){sup 0}(aq) is significant, whereas sorption is inhibited at higher pH where neptunyl carbonate complexes are the predominant species.

  14. Critical role of water content in the formation and reactivity of uranium, neptunium, and plutonium iodates under hydrothermal conditions: implications for the oxidative dissolution of spent nuclear fuel.

    Science.gov (United States)

    Bray, Travis H; Ling, Jie; Choi, Eun Sang; Brooks, James S; Beitz, James V; Sykora, Richard E; Haire, Richard G; Stanbury, David M; Albrecht-Schmitt, Thomas E

    2007-04-30

    The reactions of 237NpO2 with excess iodate under acidic hydrothermal conditions result in the isolation of the neptunium(IV), neptunium(V), and neptunium(VI) iodates, Np(IO3)4, Np(IO3)4.nH2O.nHIO3, NpO2(IO3), NpO2(IO3)2(H2O), and NpO2(IO3)2.H2O, depending on both the pH and the amount of water present in the reactions. Reactions with less water and lower pH favor reduced products. Although the initial redox processes involved in the reactions between 237NpO2 or 242PuO2 and iodate are similar, the low solubility of Pu(IO3)4 dominates product formation in plutonium iodate reactions to a much greater extent than does Np(IO3)4 in the neptunium iodate system. UO2 reacts with iodate under these conditions to yield uranium(VI) iodates solely. The isotypic structures of the actinide(IV) iodates, An(IO3)4 (An=Np, Pu), are reported and consist of one-dimensional chains of dodecahedral An(IV) cations bridged by iodate anions. The structure of Np(IO3)4.nH2O.nHIO3 is constructed from NpO9 tricapped-trigonal prisms that are bridged by iodate into a polar three-dimensional framework structure. Second-harmonic-generation measurements on a polycrystalline sample of the Th analogue of Np(IO3)4.nH2O.nHIO3 reveal a response of approximately 12x that of alpha-SiO2. Single-crystal magnetic susceptibility measurements of Np(IO3)4 show magnetically isolated Np(IV) ions.

  15. Effect of Reducing Groundwater on the Retardation of Redox-Sensitive Radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Zavarin, M; Rose, T P

    2008-04-21

    Laboratory batch sorption experiments were used to investigate variations in the retardation behavior of redox-sensitive radionuclides. Water-rock compositions used during these experiments were designed to simulate subsurface conditions at the Nevada Test Site (NTS), where a suite of radionuclides were deposited as a result of underground nuclear testing. Experimental redox conditions were controlled by varying the oxygen content inside an enclosed glove box and by adding reductants into the testing solutions. Under atmospheric (oxidizing) conditions, the radionuclide distribution coefficients varied with the mineralogical composition of the sorbent and the water chemistry. Under reducing conditions, distribution coefficients showed marked increases for {sup 99}Tc and {sup 237}Np in devitrified tuff, but much smaller variations in alluvium, carbonate rock, and zeolitic tuff. This effect was particularly important for {sup 99}Tc, which tends to be mobile under oxidizing conditions. Unlike other redox-sensitive radionuclides, iodine sorption may decrease under reducing conditions when I{sup -} is the predominant species. Overall, sorption of U to alluvium, devitrified tuff, and zeolitic tuff under atmospheric conditions was less than in the glove-box tests. However, the mildly reducing conditions achieved here were not likely to result in substantial U(VI) reduction to U(IV). Sorption of Pu was not affected by the decreasing redox conditions achieved in this study, as the predominant sorbed Pu species in all conditions was expected to be the low-solubility and strongly sorbing Pu(OH){sub 4}. Depending on the aquifer lithology, the occurrence of reducing conditions along a groundwater flowpath could potentially contribute to the retardation of redox-sensitive radionuclides {sup 99}Tc and {sup 237}Np, which are commonly identified as long-term dose contributors in the risk assessment in various nuclear facilities.

  16. Minor Actinides Loading Optimization for Proliferation Resistant Fuel Design - BWR

    Energy Technology Data Exchange (ETDEWEB)

    G. S. Chang; Hongbin Zhang

    2009-09-01

    One approach to address the United States Nuclear Power (NP) 2010 program for the advanced light water reactor (LWR) (Gen-III+) intermediate-term spent fuel disposal need is to reduce spent fuel storage volume while enhancing proliferation resistance. One proposed solution includes increasing burnup of the discharged spent fuel and mixing minor actinide (MA) transuranic nuclides (237Np and 241Am) in the high burnup fuel. Thus, we can reduce the spent fuel volume while increasing the proliferation resistance by increasing the isotopic ratio of 238Pu/Pu. For future advanced nuclear systems, MAs are viewed more as a resource to be recycled, and transmuted to less hazardous and possibly more useful forms, rather than simply disposed of as a waste stream in an expensive repository facility. MAs play a much larger part in the design of advanced systems and fuel cycles, not only as additional sources of useful energy, but also as direct contributors to the reactivity control of the systems into which they are incorporated. A typical boiling water reactor (BWR) fuel unit lattice cell model with UO2 fuel pins will be used to investigate the effectiveness of adding MAs (237Np and/or 241Am) to enhance proliferation resistance and improve fuel cycle performance for the intermediate-term goal of future nuclear energy systems. However, adding MAs will increase plutonium production in the discharged spent fuel. In this work, the Monte-Carlo coupling with ORIGEN-2.2 (MCWO) method was used to optimize the MA loading in the UO2 fuel such that the discharged spent fuel demonstrates enhanced proliferation resistance, while minimizing plutonium production. The axial averaged MA transmutation characteristics at different burnup were compared and their impact on neutronics criticality and the ratio of 238Pu/Pu discussed.

  17. Determination of Neptunium, Americium and Curium in Spent Nuclear Fuel Samples by Alpha Spectrometry Using {sup 239}Np and {sup 243}Am as a Spike and a Tracer

    Energy Technology Data Exchange (ETDEWEB)

    Jeo, Kih-Soo; Song, Byung-Chul; Kim, Young-Bok; Han, Sun-Ho; Jeon, Young-Shin; Jung, Euo-Chang; Jee, Kwang-Yong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2007-07-01

    Determination of actinide elements and fission products in spent nuclear fuels is of importance for a burnup determination and source term evaluation. Especially, the amounts of uranium and plutonium isotopes are used for the evaluation of a burnup credit in spent nuclear fuels. Additionally, other actinides such as Np, Am and Cm in spent nuclear fuel samples is also required for the purposes mentioned above. In this study, {sup 237}Np, {sup 241}Am and {sup 244}Cm were determined by an alpha spectrometry for the source term data for high burnup spent nuclear fuels ranging from 37 to 62.9 GWD/MtU as a burnup. Generally, mass spectrometry has been known as the most powerful method for isotope determinations such as high concentrations of uranium and plutonium. However, in the case of minor actinides such as Np, Am and Cm, alpha spectrometry would be recommended instead. Determination of the transuranic elements in spent nuclear fuel samples is different from that for environmental samples because the amount of each nuclide in the spent fuel samples is higher and the relative ratios between each nuclide are also different from those for environmental samples. So, it is important to select an appropriate tracer and an optimum sample size depending on the nuclides and analytical method. In this study {sup 237}Np was determined by an isotope dilution alpha(gamma) spectrometry using {sup 239}Np as a spike, and {sup 241}Am and curium isotopes were determined by alpha spectrometry using {sup 243}Am as a tracer. The content of each nuclide was compared with that by the Origen-2 code.

  18. Preconceptual Feasibility Study to Evaluate Alternative Means to Produce Plutonium-238

    Energy Technology Data Exchange (ETDEWEB)

    John D. Bess; Matthew S. Everson

    2013-02-01

    There is currently no large-scale production of 238Pu in the United States. Feasibility studies were performed at the Idaho National Laboratory to assess the capability of developing alternative 238Pu production strategies. Initial investigations indicate potential capability to provision radioisotope-powered systems for future space exploration endeavors. For the short term production of 238Pu, sealed canisters of dilute 237Np solution in nitric acid could be irradiated in the Advanced Test Reactor (ATR). Targets in the large and medium “I” positions of the ATR were irradiated over a simulated period of 306 days and analyzed using MCNP5 and ORIGEN2.2. Approximately 0.5 kg of 238Pu could be produced annually in the ATR with purity greater than 92%. Optimization of the irradiation cycles could further increase the purity to greater than 98%. Whereas the typical purity of space batteries is between 80 to 85%, the higher purity 238Pu produced in the ATR could be blended with existing lower-purity inventory to produce useable material. Development of irradiation methods in the ATR provides the fastest alterative to restart United States 238Pu production. The analysis of 238Pu production in the ATR provides the technical basis for production using TRIGA® (Training, Research, Isotopes, General Atomics) nuclear reactors. Preliminary analyses envisage a production rate of approximately 0.7 kg annually using a single dedicated 5-MW TRIGA reactor with continuous flow loops to achieve high purity product. Two TRIGA reactors represent a robust means of providing at over 1 kg/yr of 238Pu annually using dilute solution targets of 237Np in nitric acid. Further collaboration and optimization of reactor design, radiochemical methods, and systems analyses would further increase annual 238Pu throughput, while reducing the currently evaluated reactor requirements.

  19. Electron spin resonance (ESR) dating of hominid-bearing deposits in the Caverna delle Fate, Ligure, Italy

    Science.gov (United States)

    Falgueres, Christophe; Yokoyama, Yuji; Bibron, Roland

    1990-07-01

    Stalagmitic floors interstratified with Mousterian deposits from the Caverna delle Fate (Italy) have been dated by the electron spin resonance (ESR) method. Three samples dated fall between 60,000 and 74,000 yr and indicate the age of the Mousterian deposits. They are in good agreement with ages determined by nondestructive γ-ray spectrometry of the human remains from 231Pa/ 235U and 230Th /234U ratios, which are, respectively, 75,000 -14,000+21,000 and 82,000 -25,000+36,000 yr. These dates are consistent with the morphological characteristics of the bones as Neanderthal remains.

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

    Science.gov (United States)

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

    2016-04-01

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

  1. Changes in the geometry and strength of the Atlantic meridional overturning circulation during the last glacial (20-50 ka)

    Science.gov (United States)

    Burckel, Pierre; Waelbroeck, Claire; Luo, Yiming; Roche, Didier M.; Pichat, Sylvain; Jaccard, Samuel L.; Gherardi, Jeanne; Govin, Aline; Lippold, Jörg; Thil, François

    2016-11-01

    We reconstruct the geometry and strength of the Atlantic meridional overturning circulation during the Heinrich stadial 2 and three Greenland interstadials of the 20-50 ka period based on the comparison of new and published sedimentary 231Pa / 230Th data with simulated sedimentary 231Pa / 230Th. We show that the deep Atlantic circulation during these interstadials was very different from that of the Holocene. Northern-sourced waters likely circulated above 2500 m depth, with a flow rate lower than that of the present-day North Atlantic deep water (NADW). Southern-sourced deep waters most probably flowed northwards below 4000 m depth into the North Atlantic basin and then southwards as a return flow between 2500 and 4000 m depth. The flow rate of this southern-sourced deep water was likely larger than that of the modern Antarctic bottom water (AABW). Our results further show that during Heinrich stadial 2, the deep Atlantic was probably directly affected by a southern-sourced water mass below 2500 m depth, while a slow, southward-flowing water mass originating from the North Atlantic likely influenced depths between 1500 and 2500 m down to the equator.

  2. Assessment of natural radioactivity in wall paints of commercial use in Brazil; Avaliacao da radioatividade natural em tintas de uso comercial no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Leandro Milhomens da

    2016-11-01

    Natural radioactivity in soils, rocks and construction materials, due to {sup 40}K and the natural series of {sup 232}Th and {sup 2}'3{sup 8}U, is the main contribution to external exposure in mankind. In this work, activity concentrations of {sup 226}Ra ({sup 238}U series), {sup 232}Th and {sup 4}'0K were determined for 50 white latex wall paints samples, commercialized in Brazil, namely 15 Economic quality samples, 15 Standard quality samples and 20 Premium quality samples and for a single titanium dioxide sample. The samples were tightly sealed and stored for a minimum period of 30 days, to reach the radioactive secular equilibrium from {sup 238}U and {sup 232}Th series, then measured by high resolution gamma ray spectrometry. The activity concentration was determined using the weighted average concentrations of {sup 214}Pb and {sup 214}Bi for {sup 226}Ra and {sup 228}Ac, {sup 212}Pb and {sup 212}Bi for {sup 232}Th. The {sup 4}'0K activity concentration was determined by its single transition of 1460.8 keV. Self attenuation correction factors of the samples whose densities are higher than 1.0 g.cm{sup -3}, were determined and used to make the necessary corrections. The radiological indices radium equivalent activity (Ra{sub eq}), activity concentration index (I{sub γ}), internal exposure risk index (H{sub in}) and external exposure risk index (H{sub ex}) and also the absorbed dose rate (D) and annual effective dose (D{sub ef}) were calculated from the activity concentrations of {sup 226}Ra, {sup 232}Th and {sup 40}K. The activity concentration values for {sup 226}Ra ranged from under the minimum detectable activity to 38.7 Bq.kg{sup -1}, for {sup 232}Th from under the minimum detectable activity to 101.2 Bq.kg{sup -1} and for {sup 40}K from under the minimum detectable activity to 256 Bq.kg{sup -1}. Ra{sub eq} ranged from 1.41 Bq.kg{sup -1} to 203 Bq.kg{sup -1}, I{sub γ} ranged from 0.0047 to 0.720, H{sub in} from 0.0076 to 0.653 and H{sub ex

  3. Assessment of environmental radioactivity for Batman, Turkey.

    Science.gov (United States)

    Damla, Nevzat; Cevik, Ugur; Kobya, Ali Ihsan; Ataksor, Berna; Isik, Umit

    2010-01-01

    The province of Batman, located in southern Anatolia, has a population of approximately 500,000. To our knowledge, there exists no information regarding the environmental radioactivity in this province. Therefore, gamma activity measurements in soil, building materials and water samples and an indoor radon survey have been carried out in the Batman province. The mean activity concentrations of the natural radionuclides (226Ra, 232Th and 40K) and a fission product (137Cs) were 35+/-8, 25+/-10, 274+/-167 and 12+/-7 Bq kg(-1), respectively, in the soil samples. The concentrations of 226Ra, 232Th and 40K in the selected building materials ranged from 18 to 48 Bq kg(-1), 8 to 49 Bq kg(-1) and 68 to 477 Bq kg(-1), respectively. All the calculated radium equivalent (Raeq) activity values of the building material samples are lower than the limit of 370 Bq kg(-1), equivalent to a gamma-dose of 1.5 mSv year(-1). The activity concentrations of 226Ra, 232Th and 40K in tap waters collected from the study area were determined with mean specific activity concentrations of 42+/-15, 35+/-9 and 524+/-190 mBq L(-1), respectively. Indoor radon measurements were made at 95 dwellings in Batman using a CR-39 detector. The radon concentration levels were found to vary from 23 to 145 Bq m(-3). The arithmetic mean of the measured radon concentration levels was found to be 84 Bq m(-3) with a standard deviation value of 23 Bq m(-3). The measurement results obtained in this study did not significantly differ from those taken in other parts of the country. The data generated in this study can be used to determine whether the Batman province is in a normal or high background radiation area and provides a valuable database for future estimations of the impact of radioactive pollution.

  4. Natural radionuclide concentrations in two phosphate ores of east Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Lakehal, Ch. [Department of Physics, Mentouri Constantine University, 25000 Constantine (Algeria); Ramdhane, M., E-mail: ramdhane@hotmail.co [Department of Physics, Mentouri Constantine University, 25000 Constantine (Algeria); Boucenna, A. [Department of Physics, Ferhat-Abbas University, 19000 Setif (Algeria)

    2010-05-15

    Ore is considered as an important source of many elements such as the iron, phosphorus, and uranium. Concerning the natural radionuclides, their concentrations vary from an ore to other depending on the chemical composition of each site. In this work, two phosphate ores found in East of Algeria have been chosen to assess the activity concentration of natural radionuclides represented mainly by three natural radioactive series {sup 238}U, {sup 235}U and {sup 232}Th, and the primordial radionuclide {sup 40}K where they were determined using ultra-low background, high-resolution gamma-ray spectroscopy. The measured activity concentrations of radioactive series ranged from 6.2 +- 0.4 to 733 +- 33 Bq.kg{sup -1} for the {sup 232}Th series, from 249 +- 16 to 547 +- 39 Bq.kg{sup -1} for the {sup 238}U series, around 24.2 +- 2.5 Bq.kg{sup -1} for the {sup 235}U series, and from 1.4 +- 0.2 to 6.7 +- 0.7 Bq.kg{sup -1} for {sup 40}K. To assess exposure to gamma radiation in the two ores, from specific activities of {sup 232}Th, {sup 40}K and {sup 226}Ra, three indexes were determined: Radium equivalent (Ra{sub eq}), external and internal hazard indexes (H{sub ex} and H{sub in}), their values ranged from 831 +- 8 to 1298 +- 14 Bq.kg{sup -1} for Ra{sub eq}, from 2.2 +- 0.4 to 3.5 +- 0.7 Bq.kg{sup -1} for H{sub ex}, and from 4.2 +- 0.7 to 4.5 +- 0.7 Bq.kg{sup -1} for H{sub in}.

  5. Radiation levels in samples of dicalcium phosphate (DCP) and bovine and poultry rations by gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Luz Filho, Isaias Venancio da; Scheibel, Viviane; Appoloni, Carlos Roberto, E-mail: isaiasfilhojr@yahoo.com.b [Universidade Estadual de Londrina (UEL), PR (Brazil). Dept. de Fisica

    2009-07-01

    The objective of the present work is to determine the radiation levels found in bovine rations and in the dicalcium phosphate (DCP) feed supplement. Knowledge of the radiation levels in samples of rations and DCP for cattle is important, because they are directly and indirectly-part of the human diet. In order to obtain this data, gamma-ray spectrometry technique was used, employing a HPGe detector of 66% of relative efficiency, with an energy resolution of 2.03 KeV for the {sup 60}Co 1332.46 KeV line. The radioactive activity of the radionuclides {sup 40}K, {sup 137}Cs, {sup 238}U, {sup 232}Th and its respective decay series was measured. The accommodation recipient of the samples was a Marinelli beaker of 1 L. The {sup 238}U series activities were calculated through {sup 214}Pb and {sup 214}Bi activities, and the {sup 232}Th series' activity was calculated through the {sup 228}Ac, {sup 212}Pb, {sup 212}Bi and {sup 208}Tl values. The DCP samples and the rations measured in this work were produced in Londrina city, Brazil, in the second semester of 2007. Among the rations, the largest {sup 40}K and {sup 228}Ra activities were found in the ration sample for milk cattle, 402 +- 14 and 1.71 +- 0.10 Bq/kg, respectively. The ration for beef cattle yielded the largest activity for {sup 226}Ra, 1.51 + 0.93 Bq/kg. In the DCP sample, the activities for the {sup 238}U, {sup 40}K and {sup 232}Th were respectively 83 +- 26; 46.6 +- 2.8 and 7.79 +- 0.70 Bq/kg. The MDA values for {sup 137}Cs varied from 0.037 to 0.29 Bq/kg. (author)

  6. Assessment of gamma radiation exposure and distribution of natural radioactivity in beach sands associated with plutonic rocks of Greece

    Science.gov (United States)

    Papadopoulos, Argyrios; Koroneos, Antonios; Christofides, Georgios; Stoulos, Stylianos

    2016-04-01

    This study aims to evaluate the activity concentrations of 238U, 226Ra, 232Th, 228Th and 40K along beaches of Greece associated with plutonic rocks. They range from 6-940, 1-2292, 5-10143, 5-9953 and 27-1319 Bq/kg respectively, with some of them representing the highest values of natural radioactivity measured in sediments in Greece. The investigated beaches include Sithonia peninsula (Chalkidiki, N. Greece), some islands of the Aegean Sea (Mykonos, Paros, Naxos, Serifos, Ikaria), the area of Kavala (N. Greece), Samothraki island, NE Chalkidiki and Maronia (NE Greece). Several of these places are associated with high touristic activity such as Mykonos, Naxos, Paros, Serifos, Ikaria, Sithonia and Kavala. The (% wt.) heavy magnetic fraction (HM) (allanite, amphibole, mica, clinopyroxene, magnetite and hematite), the heavy non-magnetic fraction (HNM) (monazite, zircon, titanite and apatite) and the total heavy fraction (TH), were correlated with the concentrations of the measured radionuclides in the bulk samples. The heavy fractions seem to control the activity concentrations of 238U and 232Th of all the samples, showing some local differences in the main 238U and 232Th mineral carrier. The measured radionuclides in the beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parental rocks, so as to provide data upon their enrichment or depletion. The highest values of the equivalent dose have been reported in Mykonos, Naxos, Kavala and Sithonia. The annual equivalent dose which should be limited to at least 1 mSv y-1, varies between 0.003 and 0.759 mSv y-1 for tourists and from 0.012 to 3.164 mSv y-1 for local people working on the beach.

  7. Comparative analysis of dose rates in bricks determined by neutron activation analysis, alpha counting and X-ray fluorescence analysis for the thermoluminescence fine grain dating method

    Science.gov (United States)

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

    2014-11-01

    In order to evaluate the age from the equivalent dose and to obtain an optimized and efficient procedure for thermoluminescence (TL) dating, it is necessary to obtain the values of both the internal and the external dose rates from dated samples and from their environment. The measurements described and compared in this paper refer to bricks from historic buildings and a fine-grain dating method. The external doses are therefore negligible, if the samples are taken from a sufficient depth in the wall. However, both the alpha dose rate and the beta and gamma dose rates must be taken into account in the internal dose. The internal dose rate to fine-grain samples is caused by the concentrations of natural radionuclides 238U, 235U, 232Th and members of their decay chains, and by 40K concentrations. Various methods can be used for determining trace concentrations of these natural radionuclides and their contributions to the dose rate. The dose rate fraction from 238U and 232Th can be calculated, e.g., from the alpha count rate, or from the concentrations of 238U and 232Th, measured by neutron activation analysis (NAA). The dose rate fraction from 40K can be calculated from the concentration of potassium measured, e.g., by X-ray fluorescence analysis (XRF) or by NAA. Alpha counting and XRF are relatively simple and are accessible for an ordinary laboratory. NAA can be considered as a more accurate method, but it is more demanding regarding time and costs, since it needs a nuclear reactor as a neutron source. A comparison of these methods allows us to decide whether the time- and cost-saving simpler techniques introduce uncertainty that is still acceptable.

  8. Determination of activity concentration of natural and artificial radionuclides in sand samples from mediterranean coast of Antalya in Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Eke, Canel [Akdeniz Univ., Div. of Physics Education, Antalya (Turkey); Akdeniz Univ., Nuekleer Bilimler Uygulama ve Arastirma Merkezi, Antalya (Turkey); Boztosun, Ismail [Akdeniz Univ., Nuekleer Bilimler Uygulama ve Arastirma Merkezi, Antalya (Turkey); Akdeniz Univ., Dept. of Physics, Antalya (Turkey)

    2015-07-15

    In this paper, we attempt to determine the activity concentration of natural and artificial radionuclides in 37 sand samples from the Mediterranean coast of Antalya in Turkey by using a high purity Germanium (HpGe) detector. {sup 238}U, {sup 232}Th, {sup 40}K and {sup 137}Cs activity concentrations, absorbed dose rate, annual effective dose equivalent, radium equivalent activity, external and internal hazard index of sand samples are determined respectively. The average values are 13.43 ± 0.21 Bq/kg, 6.96 ± 0.06 Bq/kg and, 122.46 ± 18.58 Bq/kg, for {sup 238}U, {sup 232}Th and {sup 40}K respectively. Most of the activity concentration values are less than below minimum detection limit for {sup 137}Cs. The average values of the absorbed dose rate D (nGy/h), annual effective dose equivalent AEDE(μSv/y), radium equivalent activity Ra{sub eq} (Bq/kg), external hazard index H{sub ex} and internal hazard index H{sub in} are 15.52 nGy/h, 19.03 μSv/y, 32.81 Bq/kg, 0.09 and 0.12 respectively. It is observed that {sup 238}U, {sup 232}Th, {sup 40}K and {sup 137}Cs activity concentrations, absorbed dose rate, annual effective dose equivalent, radium equivalent activity are in the limit of the published values, external and internal hazard index values are less than unity.

  9. Radiation hazards evaluation for selected sand samples from Camburi beach, Vitoria, Espirito Santo, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Livia F.; Pecequilo, Brigitte R.S., E-mail: lfbarros@ipen.br, E-mail: brigitte@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    In this work, a single location at Camburi beach, known to be a naturally high background region, was studied. Radiation hazards indexes and annual effective dose were evaluated from the {sup 226}Ra, {sup 232}Th and {sup 40}K sands activities concentrations. Sand samples were monthly collected during 2011, dried, sealed in standard 100 mL HPDE polyethylene flasks and measured by high resolution gamma spectrometry after a 4 weeks in-growth period. The {sup 226}Ra concentration was determined from the weighted average concentrations of {sup 214}Pb and {sup 214}Bi. The {sup 232}Th concentration was determined from the weighted average concentrations of {sup 228}Ac, {sup 212}Pb and {sup 212}Bi and the {sup 4}0K from its single gamma transition. The results, considering samples gamma-rays self-attenuation, show activities concentrations in the range from 6 Bq kg{sup -1} to 39 Bq kg{sup -1} for {sup 226}Ra, 13 Bq kg{sup -1} to 161 Bq kg{sup -1} for {sup 232}Th, and 7 Bq kg{sup -1} to 65 Bq kg{sup -1} for {sup 40}K. The radium equivalent activity for the studied samples ranged from 26 Bq kg{sup -1} to 274 Bq kg{sup -}'1. The external and internal hazard indexes varied, respectively, from 0.07 to 0.74 and from 0.09 to 0.85. The annual effective dose values laid from 0.07 mSv.y{sup -1} to 0.72 mSv.y{sup -}'1. All values obtained in this work are below the radiological protection recommended limits. (author)

  10. Natural uranium and thorium isotopes in sediment cores off Malaysian ports

    Science.gov (United States)

    Yusoff, Abdul Hafidz; Sabuti, Asnor Azrin; Mohamed, Che Abd Rahim

    2015-06-01

    Sediment cores collected from three Malaysian marine ports, namely, Kota Kinabalu, Labuan and Klang were analyzed to determine the radioactivities of 234U, 238U, 230Th, 232Th and total organic carbon (TOC) content. The objectives of this study were to determine the factors that control the activity of uranium isotopes and identify the possible origin of uranium and thorium in these areas. The activities of 234U and 238U show high positive correlation with TOC at the middle of sediment core from Kota Kinabalu port. This result suggests that activity of uranium at Kota Kinabalu port was influenced by organic carbon. The 234U/238U value at the upper layer of Kota Kinabalu port was ≥1.14 while the ratio value at Labuan and Klang port was ≤ 1.14. These results suggest a reduction process occurred at Kota Kinabalu port where mobile U(VI) was converted to immobile U(IV) by organic carbon. Therefore, it can be concluded that the major input of uranium at Kota Kinabalu port is by sorptive uptake of authigenic uranium from the water column whereas the major inputs of uranium to Labuan and Klang port are of detrital origin. The ratio of 230Th/232Th was used to estimate the origin of thorium. Low ratio value (lt; 1.5) at Labuan and Klang ports support the suggestion that thorium from both areas were come from detrital input while the high ratio (> 1.5) of 230Th/232Th at Kota Kinabalu port suggest the anthropogenic input of 230Th to this area. The source of 230Th is probably from phosphate fertilizers used in the oil-palm cultivation in Kota Kinabalu that is adjacent to the Kota Kinabalu port.

  11. Assessment of radionuclides and heavy metals in marine sediments along the Upper Gulf of Thailand

    Science.gov (United States)

    Khuntong, S.; Phaophang, C.; Sudprasert, W.

    2015-05-01

    Due to the Fukushima Daiichi nuclear disaster in 2011 and the development of nuclear power plant in neighboring countries such as Vietnam in the near future, radionuclide assessment in marine sediment during 2010 - 2011 may be useful as background levels for radiation protection in Thailand. Marine sediments (10 samples) were collected approximately 1 km away from the coastline along Chonburi to Pattaya, Chonburi Province. The sediments were ground and sieved through 2-mm test sieve after air drying. Radionuclides were measured with a gamma spectrometer equipped with a well-calibrated HPGe detector. The samples were prepared in the same geometry as the reference material. The optimal counting time was 60,000 - 80,000 s for statistical evaluation and uncertainties. No contamination of 137Cs as an artificial radionuclide was found. Naturally-occurring radionuclides including 238U, 232Th and 40K were found. The mean specific activities of 238U, 232Th and 40K were 44 ± 10, 59 ± 17 and 463 ± 94 Bq/kg in the rainy season (2010); 41 ± 6, 50 ± 9 and 484 ± 83 Bq/kg in the winter (2010), and 39 ± 6, 41 ± 7 and 472 ± 81 Bq/kg in the summer (2011), respectively. The mean specific activities were higher than the values in the UNSCEAR report of 35, 30 and 400 Bq/kg for 238U, 232Th and 40K, respectively. From the measured specific activities, the absorbed dose rate, radium equivalent activity, external hazard index and annual external effective dose rate were calculated in order to assess the health risk. No radiation hazards related to the radioactivity in the sediment were expected. The accumulation of radionuclides varied with the particle size and the organic matter content in the sediment. The accumulation of heavy metals showed similar results to that of the radionuclides in the sediment.

  12. Thorotrast: analysis of the time evolution of its α activity concentration, in the 70 years following the chemical purification of Thorium.

    Science.gov (United States)

    Bianconi, A; Corradini, M; Leali, M; Lodi Rizzini, E; Venturelli, L; Zurlo, N

    2013-09-01

    We simulate the α-activity of the Thorium series elements present in the contrast medium named Thorotrast, used until 1960 and cause of certified deaths until today. Assuming, as active components at t=0, (232)Th and (228)Th in the same relative concentration they have in nature, α-activity oscillates for some decades before reaching a stationary value that in absence of biological depletion would be AST =24000Bq/g. Our Montecarlo code generates the nuclear decays of the Thorium series with and without in-vivo biological depletion, arriving to three kinds of results for the activity: 1) Theoretical activity concentration (no biological depletion). Our result is fitted by: A(t)=A(ST).{[1-exp(-t/10)]+[exp(-t/tB)(1-0.8exp(-t/tA))]}, with t in years, tA=1.07.10(-2) years, and tB=2.38 years. 2) Weak biological depletion (228Ra/232 Th equilibrium activity ratio 0.6, 224Ra/228Ra e.a.r 0.9, 10% excretion for 220Rn). The ratio of the activity concentration to the theoretical activity concentration is fitted by: A weak (t)/A(t)=0.61+0.29 exp[-(t/15)2] (t in years). 3) Strong biological depletion (228Ra/232Th e.a.r 0.4, 224Ra/228Ra e.a.r. 0.8, 10% excretion for 220Rn). The ratio of the activity concentration to the theoretical activity concentration is fitted by A(strong)(t)/A(t)=0.44+0.4 exp[-(t/13)2](t in years). We also report fluctuation calculation for two cases where standard statistical behavior is not expected.

  13. Radionuclide contents and radiological risk to the population due to raw minerals and soil samples from the mining sites of quality ceramic and pottery industries in Akwa Ibom, Nigeria; Contenu en radionucleides et risque radiologique aux populations d'echantillons de sols et de mineraux bruts issus de sites miniers des industries de la poterie et de la ceramique de qualite a Akwa Ibom, Nigeria

    Energy Technology Data Exchange (ETDEWEB)

    Jibiri, N.N.; Esen, N.U. [Radiation and Health Physics Research Laboratory, Department of Physics, University of Ibadan, Ibadan (Nigeria)

    2011-01-15

    Samples of domestically produced industrial raw minerals and soil samples from three mining sites of quality ceramic/smelting and pottery industries in Akwa Ibom, Nigeria, were collected and analyzed for their {sup 226}Ra, {sup 232}Th and {sup 40}K contents using gamma-ray spectroscopy. The range of activity concentrations of the radionuclides in the industrial raw minerals were 17.55 {+-} 1.63 to 80.99 {+-} 2.61 Bq.kg{sup -1} for {sup 226}Ra, 7.64 {+-} 0.77 to 23.94 {+-} 0.92 Bq.kg{sup -1} for {sup 232}Th and 63.22 {+-} 3.43 to 503.90 {+-} 5.69 Bq.kg{sup -1} for {sup 40}K, while in the soil samples they varied from 2.87 to 34.78 Bq.kg{sup -1}, 7.02 to 24.47 Bq.kg{sup -1} and 7.05 to 162.81 Bq.kg{sup -1} for {sup 226}Ra, {sup 232}Th and {sup 40}K, respectively. These results, along with the estimated absorbed dose rates, annual effective dose rates, radium equivalent (Ra{sub eq}), external hazard index (H{sub ex}), internal hazard index (H{sub in}) and representative of the gamma index (I{gamma}r) are presented. The results obtained were below the internationally accepted safe limits. Therefore, the analyzed samples could be used in the local industries in the area as component raw materials and/or as building materials. Also, the mining activities of these minerals in the area have not significantly affected the natural radiation dose levels in the area, hence the resulting dose to the population is therefore considered generally low. (authors)

  14. Terrestrial gamma dose rate, radioactivity and radiological hazards in the rocks of an elevated radiation background in Juban District, Ad Dali' Governorate, Yemen.

    Science.gov (United States)

    Abdurabu, Wedad Ali; Ramli, Ahmad Termizi; Saleh, Muneer Aziz; Heryansyah, Arien; Alnhary, Anees; Fadhl, Shadi

    2016-03-01

    This study aims to evaluate natural radiation and radioactivity in the rock and to assess the corresponding health risk in a region of elevated background radiation in Juban District, Ad Dali' Governorate, Yemen. The mean external gamma dose rate was 374 nGy h(-1) which is approximately six times the world average. The measured results were used to compute annual effective dose equivalent, collective effective dose and excess lifetime cancer risk, which are 2.298 mSv, 61.95 man Sv y(-1) and 8.043  ×  10(-3), respectively. Rocks samples from different geological formations were analyzed for quantitative determination of (226)Ra, (232)Th and (40)K. The specific activity of the rocks samples ranges from 7  ±  1 Bq Kg(-1) to 12 513  ±  329 Bq Kg(-1) for (232)Th, from 6  ±  1 Bq kg(-1) to 3089  ±  74 Bq kg(-1) for (226)Ra and 702  ±  69 Bq kg(-1) to 2954  ±  285 Bq kg(-1) for (40)K. (232)Th is the main contributor to gamma dose rate from the rock samples. Indicators of radiological health impact, radium equivalent activity and external hazard index are 3738 Bq kg(-1) and 10.10, respectively. The mean external hazard index was ten times unity in the studied locations in Juban District, which is higher than the recommended value.

  15. Environmental-Impact Assessment of Natural Radioactivity Around a Traditional Mining Area in Al-Ibedia, Sudan.

    Science.gov (United States)

    Idriss, Hajo; Salih, Isam; Alaamer, Abdulaziz S; Saleh, Almuaiz; Abdelgali, M Y

    2016-05-01

    Recently, in the Sudan, traditional gold mining has been growing rapidly and has become a very attractive and popular economic activity. Mining activity is recognized as one of the sources of radioactivity contamination. Hence, the radioactivity concentration and radiological hazard due to exposure of radionuclides (226)Ra, (232)Th, and (40)K were evaluated. The measurements were performed using gamma-ray spectrometry with an NaI (Tl) detector. The results show that (226)Ra, (232)Th, and (40)K activity concentration ranged from 2.66 to 18.47, 9.20 to 51.87, and 0.17 to 419.77 Bq/kg with average values of 7.54 ± 4.91, 20.74 ± 11.29, and 111.87 ± 136.84 Bq/kg, respectively. In contrast, (222)Rn in soil, (222)Rn in air, and (226)Ra in vegetables along with radiation dose were computed and compared with the international recommended levels. Potential radiological effects to miners and the public due to (226)Ra, (232)Th, (40)K, and (222)Rn are insignificant. (226)Ra transferred to vegetables appears to be negligible compared with the allowable limit 1.0 mSv/year set by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The average value of the annual gonadal dose equivalent (AGDE) is lower than the global average of 300 µSv/year (UNSCEAR 2000). However, some locations exhibit values >300 µSv/year. To the best of our knowledge, so far there seems to be no data regarding radioactivity monitoring in traditional mining areas in the Sudan.

  16. Soil radioactivity levels, radiological maps and risk assessment for the state of Kuwait.

    Science.gov (United States)

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

    2016-07-01

    An evaluation of the radioactivity levels associated with naturally occurring radioactive materials has been undertaken as part of a systematic study to provide a surface radiological map of the State of Kuwait. Soil samples from across Kuwait were collected, measured and analysed in the current work. These evaluations provided soil activity concentration levels for primordial radionuclides, specifically members of the (238)U and (232)Th decay chains and (40)K which. The (238)U and (232)Th chain radionuclides and (40)K activity concentration values ranged between 5.9 ↔ 32.3, 3.5 ↔ 27.3, and 74 ↔ 698 Bq/kg respectively. The evaluated average specific activity concentrations of (238)U, (232)Th and (40)K across all of the soil samples have mean values of 18, 15 and 385 Bq/kg respectively, all falling below the worldwide mean values of 35, 40 and 400 Bq/kg respectively. The radiological risk factors are associated with a mean of 33.16 ± 2.46 nG/h and 68.5 ± 5.09 Bq/kg for the external dose rate and Radium equivalent respectively. The measured annual dose rates for all samples gives rise to a mean value of 40.8 ± 3.0 μSv/y while the internal and internal hazard indices have been found to be 0.23 ± 0.02 and 0.19 ± 0.01 respectively.

  17. Assessment of natural radioactivity levels in soil samples from some areas in Assiut, Egypt.

    Science.gov (United States)

    El-Gamal, Hany; Farid, M El-Azab; Abdel Mageed, A I; Hasabelnaby, M; Hassanien, Hassanien M

    2013-12-01

    The natural radioactivity of soil samples from Assiut city, Egypt, was studied. The activity concentrations of 28 samples were measured with a NaI(Tl) detector. The radioactivity concentrations of (226)Ra, (232)Th, and (40)K showed large variations, so the results were classified into two groups (A and B) to facilitate the interpretation of the results. Group A represents samples collected from different locations in Assiut and characterized by low activity concentrations with average values of 46.15 ± 9.69, 30.57 ± 4.90, and 553.14 ± 23.19 for (226)Ra, (232)Th, and (40)K, respectively. Group B represents samples mainly collected from the area around Assiut Thermal Power Plant and characterized by very high activity concentrations with average values of 3,803 ± 145, 1,782 ± 98, and 1,377 ± 78 for (226)Ra, (232)Th, and (40)K, respectively. In order to evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity (Raeq), the absorbed dose rate (D), the annual effective dose rate (E), the external hazard index (H ex), and the annual gonadal dose equivalent (AGDE) have been calculated and compared with the internationally approved values. For group A, the calculated averages of these parameters are in good agreement with the international recommended values except for the absorbed dose rate and the AGDE values which are slightly higher than the international recommended values. However, for group B, all obtained averages of these parameters are much higher by several orders of magnitude than the international recommended values. The present work provides a background of radioactivity concentrations in the soil of Assiut.

  18. Spatial and depth wise characterization of radionuclides and minerals in various beach sediments from high background radiation area, Kerala, India.

    Science.gov (United States)

    Ramasamy, V; Sundarrajan, M; Paramasivam, K; Suresh, G

    2014-11-04

    The activity concentrations ((238)U, (232)Th and (40)K) and mineralogical characterization of different layer (upper surface, first, second and third feet) Kerala beach sediments have been assessed with an aim of evaluating the radioactivity content profile, its relation to specific minerals and their distributions (spatial and depth wise). The eight different radiological indices are calculated for all samples and compared with either recommended values or the world average values of radioactivity content of the three primordial radionuclides to assess the complete radiological profile of the sediments. The radioactivity study suggests that the average specific activities of radionuclides ((238)U and (232)Th) are higher than the world average values as given in UNSCEAR reports and all radiological parameters in all layer samples are more than the recommended safety levels. These results are on the expected lines since the samples are from a well-known high background radiation area. Using FTIR, mineralogical characteristics of the sediments were analyzed and the extinction coefficient is calculated to find the relative distribution of major minerals. The calculated values show that the amount of major minerals decreases in the order of quartz>calcite>kaolinite>microcline feldspar in all layers. To confirm the results obtained from FTIR, XRD analysis was also carried out. The observations made through the XRD technique are matched with FTIR observations. Statistical analyses (cluster and factor analysis) are carried out to assess the relation between the radionuclides and minerals, and also assess their distribution patterns in different layers. The analyses suggest that the concentration of (40)K may have a strong association with the light mineral calcite and also suggest that spatial distributions of (40)K and calcite are almost similar in every layer. The concentrations of (238)U, (232)Th and absorbed dose rate are evenly distributed (spatial) and other

  19. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    Science.gov (United States)

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-01-01

    Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize. PMID:26437425

  20. Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

    Directory of Open Access Journals (Sweden)

    Adriana Eštoková

    2013-12-01

    Full Text Available The radionuclide activities of 226Ra, 232Th and 40K and radiological parameters (radium equivalent activity, gamma and alpha indices, the absorbed gamma dose rate and external and internal hazard indices of cements and cement composites commonly used in the Slovak Republic have been studied in this paper. The cement samples of 8 types of cements from Slovak cement plants and five types of composites made from cement type CEM I were analyzed in the experiment. The radionuclide activities in the cements ranged from 8.58–19.1 Bq·kg−1, 9.78–26.3 Bq·kg−1 and 156.5–489.4 Bq·kg−1 for 226Ra, 232Th and 40K, respectively. The radiological parameters in cement samples were calculated as follows: mean radium equivalent activity Raeq = 67.87 Bq·kg−1, gamma index Iγ = 0.256, alpha index Iα = 0.067, the absorbed gamma dose rate D = 60.76 nGy·h−1, external hazard index Hex = 0.182 and internal hazard index Hin was 0.218. The radionuclide activity in composites ranged from 6.84–10.8 Bq·kg−1 for 226Ra, 13.1–20.5 Bq·kg−1 for 232Th and 250.4–494.4 Bq·kg−1 for 40K. The calculated radiological parameters of cements were lower than calculated radiological parameters of cement composites.

  1. Committed dose assessment based on background outdoor gamma exposure in Chihuahua City, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Luevano G, S.; Perez T, A.; Pinedo A, C.; Renteria V, M. [Universidad Autonoma de Chihuahua, Facultad de Zootecnia y Ecologia, Perif. Francisco R. Almada Km 1, 31415 Chihuahua, Chih. (Mexico); Carrillo F, J.; Montero C, M. E., E-mail: mrenteria@uach.mx [Centro de Investigacion en Materiales Avanzados, Miguel de Cervantes 120, 31136 Chihuahua, Chih. (Mexico)

    2015-10-15

    Full text: Determining ionizing radiation in a geographic area serves to assess its effects on populations health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the committed dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, annual effective dose, and the lifetime cancer risk, 48 sampling points were randomly selected along the Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Muller counter. At the same sites, 48 soil samples were taken to obtain the activity concentrations of {sup 226}Ra, {sup 232}Th, {sup 40}K and their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Outdoor gamma dose rates ranged from 56 to 193 n Gy h{sup -1}. Results indicated that lifetime effective dose to inhabitants of Chihuahua City is in average of 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of activity concentrations in soil were 51.8, 73.1, and 1096.5 Bq kg{sup -1}, of {sup 226}Ra, {sup 232}Th and {sup 40}K, respectively. From the analysis of the spatial distribution of {sup 232}Th, {sup 226}Ra, and {sup 40}K is to north, to north-center, and to south of city, respectively. In conclusion, natural background gamma dose received by inhabitants of Chihuahua City is high and mainly due to geological characteristics of the zone. (Author)

  2. Natural radioactivity levels and heavy metals in chemical and organic fertilizers used in Kingdom of Saudi Arabia.

    Science.gov (United States)

    El-Taher, A; Althoyaib, S S

    2012-01-01

    The present work deals with identifying and determining the activity levels of natural occuring radionuclides, (226)Ra and (232)Th series, their decay products and (40)K, in chemical and organic fertilizers used in Kingdom of Saudi Arabia. A total of 30 samples: 20 phosphatic fertilizers (single super-phosphate SSP and triple super-phosphate,TSP) and 10 organic fertilizers (cow, sheep and chicken) collected from markets and farms. The gamma-ray spectrometer consists of NaI(Tl) detector and its electronic circuit was used for measuring γ-ray spectra. The ranges of radioactivity levels of (226)Ra, (232)Th and (40)K in chemical fertilizers are 51.5±5.2-106.3±7.5, 5.1±1.6-9.9±3.2. and 462.6±21-607.3±14Bqkg(-1), respectively. The activities of (226)Ra, (232)Th and (40)K in natural fertilizers (cow, sheep and chicken) are lower than the activities in chemical fertilizers. The obtained data are compared with available reported data from other countries in literature. The Ra(eq) in chemical fertilizer ranges from 100.37 to 161.43Bqkg(-1) and in organic fertilizer ranges from 34.07 to 102.19Bqkg(-1), which are lower than the limit of 370Bqkg(-1) adopted from NEA-OECD (1979). The average heavy metal (Pb, Cd, Ni, Co and Cr) contents of the fertilizers marketed in the Kingdom of Saudi Arabia are also determined and within the limits of those used worldwide.

  3. Natural Radioactivity in some building materials from Spain

    Energy Technology Data Exchange (ETDEWEB)

    Miro, C. [Universidad de Extremadura (UEX), 10071-Caceres (Spain); Madruga, M.J.; Reis, M. [Instituto Superior Tecnico, Universidade de Lisboa, Campus Tecnologico e Nuclear, 2695-066 Bobadela LRS (Portugal)

    2014-07-01

    Studies of natural radiation are of great importance because it is the main source of exposure of human kind. Building materials is one of the sources which cause direct radiation exposure because of their radium, thorium and potassium content. The aim of this work is to measure gamma activity due to {sup 40}K, {sup 226}Ra and {sup 232}Th in samples of commonly used as a building materials in Spain. Cement, gypsum, plaster, marble, slates, granite and wood had been analysed. These materials are used for private and public building. Radium equivalent activities (Ra{sub eq}) and various hazard indices were also calculated to assess the radiation hazard. Results were also compared with the data available in the literature for other countries of the world. Cement, gypsum and plaster samples were collected from hardware stores. Marble, slates and granite samples were taken from different quarries. And the wood samples were taken from eucalyptus trees from forest. Activity concentrations {sup 40}K-, {sup 226}Ra- and {sup 232}Th-activity was determined by gamma spectrometry using a HPGe coaxial detector. The results show that the range of average values of the activity concentrations due to {sup 40}K, {sup 226}Ra and {sup 232}Th were found between 37 and 1340 Bq/kg, 0.007 and 104 Bq/kg, and <0.005 and 75 Bq/kg, respectively. Maxima values were obtained in granite. Radium equivalent activities range from 3.7 Bq/kg to 283 Bq/kg, calculated in wood and granite, respectively. Therefore all the samples showed Raeq activities within the limit, 370 Bq/kg, set by UNSCEAR. Values of external hazard index for all samples under investigation are below the unity, while the internal hazard index for granite exhibits a value around the unity. Acknowledgements to the financial support of the Junta de Extremadura (project PRI09A092 and FEDER-group GRU09053). (authors)

  4. Natural Radionuclide Contents in Raw Materials and the Aggregate Finished Product from Dangote Cement Plc, Obajana, Kogi State, North Central Nigeria

    Directory of Open Access Journals (Sweden)

    J.O. Ajayi

    2012-11-01

    Full Text Available Assessment of gamma ray activity in raw materials and the end product in Dangote Cement from Dangote Cement Plc, Obajana and Kogi State has been investigated in this study. Gamma ray spectrometry that possesses scintillation detector was used to analyze the samples collected from the company. Samples collected as raw materials are limestone, clay, gypsum and laterite and cement as finished product. The 40K, 238U, 232Th activity concentration were detected. The concentration of 40K range from 4649±366 to 0±65 Bq/Kg with highest value in limestone and lowest in laterite. The 238U concentration is highest in gypsum range from 696±233 to 41±27 Bq/Kg in laterite. 232Th activity is below detectable limit in all the raw materials but it has activity concentration of 40±26 Bq/Kg in the finished product which may be traceable to the fact that some finished additives are present which are not in the basic raw materials of this cement under investigation. It is concluded that the natural radionuclide measured for 40K, 238U and 232Th has mean activities of 2189.75±219.5, 331.25±132.25 and 0±31 Bq/Kg respectively, while its corresponding mean absorbed dose rate in air at 1 m above the ground was calculated to be 235.61 nGy/h or 2.064 mSv/y and the aggregate finished product (cement has absorbed dose rate of 342.22 nGy/h and an effective dose equivalent of 2.998 mSv/y. The calculated absorbed doses in nGy/h and mSv/y shows that Dangote cement under consideration has higher activities of the isotopes than the permissible level suggested by ICRP (80 nGy/h or 0.7 mSv/y

  5. Role of light and heavy minerals on natural radioactivity level of high background radiation area, Kerala, India.

    Science.gov (United States)

    Ramasamy, V; Sundarrajan, M; Suresh, G; Paramasivam, K; Meenakshisundaram, V

    2014-02-01

    Natural radionuclides ((238)U, (232)Th and (40)K) concentrations and eight different radiological parameters have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation hazards. Activity concentrations ((238)U and (232)Th) and all the radiological parameters in most of the sites have higher values than recommended values. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area. In order to know the light mineral characterization of the present sediments, mineralogical analysis has been carried out using Fourier transform infrared (FTIR) spectroscopic technique. The eight different minerals are identified and they are characterized. Among the various observed minerals, the minerals such as quartz, microcline feldspar, kaolinite and calcite are major minerals. The relative distribution of major minerals is determined by calculating extinction co-efficient and the values show that the amount of quartz is higher than calcite and much higher than microcline feldspar. Crystallinity index is calculated to know the crystalline nature of quartz present in the sediments. Heavy mineral separation analysis has been carried out to know the total heavy mineral (THM) percentage. This analysis revealed the presence of nine heavy minerals. The minerals such as monazite, zircon, magnetite and illmenite are predominant. Due to the rapid and extreme changes occur in highly dynamic environments of sandy beaches, quantities of major light and heavy minerals are widely varied from site to site. Granulometric analysis shows that the sand is major content. Multivariate statistical (Pearson correlation, cluster and factor) analysis has been carried out to know the effect of mineralogy on radionuclide concentrations. The present study concluded that heavy minerals induce the (238)U and (232)Th

  6. Daily changes of radon concentration in soil gas under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Evelise G.; Oliveira, Arno Heeren de, E-mail: evelise.lara@gmail.com, E-mail: heeren@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Rocha, Zildete; Rios, Francisco Javier, E-mail: rochaz@cdtn.br, E-mail: javier@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    This work aims at relating the daily change in the radon concentration in soil gas in a Red Yellow Acrisol (SiBCS) under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity. The {sup 226}Ra, {sup 232}Th, U content and permeability were also performed. The measurements of radon soil gas were carried out by using an AlphaGUARD monitor. The {sup 226}Ra activity concentration was made by Gamma Spectrometry (HPGe); the permeability was carried out using the RADON-JOK permeameter and ICP-MS analysis to {sup 232}Th and U content. The soil permeability is 5.0 x 10{sup -12}, which is considered average. The {sup 226}Ra (22.2 ± 0.3 Bq.m{sup -3}); U content (73.4 ± 3.6 Bq.kg{sup -1}) and {sup 232}Th content (55.3 ± 4.0 Bq.kg{sup -1}) were considered above of average concentrations, according to mean values for soils typical (~ 35.0 Bq.kg{sup -1}) by UNSCEAR. The results showed a difference of 26.0% between the highest and the lowest concentration of radon in soil gas: at midnight (15.5 ± 1.0 kBq.m{sup -3}) and 3:00 pm, the highest mean radon concentration (21.0 ± 1.0 kBq.m{sup -3}). The room temperature and surface soil temperature showed equivalent behavior and the surface soil temperature slightly below room temperature during the entire monitoring time. Nevertheless, the relative humidity showed the highest cyclical behavior, showing a higher relationship with the radon concentration in soil gas. (author)

  7. Radioactivity of cigarettes and the importance of (210)Po and thorium isotopes for radiation dose assessment due to smoking.

    Science.gov (United States)

    Kubalek, Davor; Serša, Gregor; Štrok, Marko; Benedik, Ljudmila; Jeran, Zvonka

    2016-05-01

    Tobacco and tobacco smoke are very complex mixtures. In addition to various chemical and organic compounds they also contain natural radioactive elements (radionuclides). In this work, the natural radionuclide activity concentrations ((234)U, (238)U, (228)Th, (230)Th, (232)Th, (226)Ra, (210)Pb and (210)Po) of nine different cigarette samples available on the Slovenian market are reported. In addition to (210)Po, the transfer of thorium isotopes from a cigarette to a smoker's body and lungs have been determined for the first time. Cigarette smoke and exhaled air from smokers' lungs were collected from volunteer smokers (C-4 brand) to determinate what quantity of (210)Po and thorium isotopes is transferred from the tobacco to the smoker's lungs. Cigarette ash and smoked filters were also collected and analysed. Among the determined isotopes, (210)Pb and (210)Po showed the highest activity concentrations. During the smoking of one cigarette approximately 22% of (210)Po (and presumably its predecessor (210)Pb), 0.6% of (228)Th, 24% of (230)Th, and 31% of (232)Th are transferred from the cigarette and retained in the smoker's body. The estimated annual effective dose for smokers is 61 μSv/year from (210)Po; 9 μSv/year from (210)Pb; 6 μSv/year from (228)Th; 47 μSv/year from (230)Th, and 37 μSv/year from (232)Th. These results show the importance of thorium isotopes in contributing to the annual effective dose for smoking. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Measurement of Radionuclide Concentration in Some Water Resources in Markazi Province, Iran

    Directory of Open Access Journals (Sweden)

    Reza Pourimani

    2016-03-01

    Full Text Available Introduction Natural and artificial radionuclides are the main sources of human radiation exposure. These radionuclides, which are present in the environment, can be dissolved into water. Evidence suggests that radionuclides being entered the human body through drinking or hot spring water can be harmful for human health. Materials and Methods In this study,10 samples were collected from ground water resources of Arak, one sample from the surface water of Kamal-Saleh Dam, and four samples from the hot springs of Mahallat region. The specific activities of 226Ra, 232Th, 40K, and 137Cs were determined in the samples, using gamma ray spectrometry and a high-purity germanium (HPGe detector. Results Specific activities of 226Ra, 232Th, 40K, and 137Cs were determined in the water samples. The mean 226Ra activity concentrations in drinking water samples from Aman Abad, Mobarak Abad, and Taramazd wells were 7.65±1.64, 1.56±1.04, and 1.45±1.39 Bq/l, while the corresponding values for 232Th were 2.70±0.18, 0.41±0.16, and 1.27±0.44 Bq/l, respectively. The annual effective dose due to drinking water varied from 0.01 to 0.78 mSv/y. Moreover, the specific activity of 226Ra in the water samples from the orifice of Donbe, Shafa, Soleymani, and Souda hot springs varied from 0.47±0.16 to 1.90±0.21. Conclusion The calculated annual effective dose due to water consumption by Iranians was within the average annual global range. Therefore, based on the present results, radionuclide intake due to water consumption had no consequences for public health; however, it is recommended that hot spring baths use air conditioning devices.

  9. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico.

    Science.gov (United States)

    Luevano-Gurrola, Sergio; Perez-Tapia, Angelica; Pinedo-Alvarez, Carmelo; Carrillo-Flores, Jorge; Montero-Cabrera, Maria Elena; Renteria-Villalobos, Marusia

    2015-09-30

    Determining ionizing radiation in a geographic area serves to assess its effects on a population's health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h(-1). At the same sites, 48 soil samples were taken to obtain the activity concentrations of (226)Ra, (232)Th and (40)K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h(-1). Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg(-1), for (226)Ra, (232)Th and (40)K, respectively. From the analysis, the spatial distribution of (232)Th, (226)Ra and (40)K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize.

  10. Lifetime Effective Dose Assessment Based on Background Outdoor Gamma Exposure in Chihuahua City, Mexico

    Directory of Open Access Journals (Sweden)

    Sergio Luevano-Gurrola

    2015-09-01

    Full Text Available Determining ionizing radiation in a geographic area serves to assess its effects on a population’s health. The aim of this study was to evaluate the spatial distribution of the background environmental outdoor gamma dose rates in Chihuahua City. This study also estimated the annual effective dose and the lifetime cancer risks of the population of this city. To determine the outdoor gamma dose rate in air, the annual effective dose and the lifetime cancer risk, 48 sampling points were randomly selected in Chihuahua City. Outdoor gamma dose rate measurements were carried out by using a Geiger-Müller counter. Outdoor gamma dose rates ranged from 113 to 310 nGy·h−1. At the same sites, 48 soil samples were taken to obtain the activity concentrations of 226Ra, 232Th and 40K and to calculate their terrestrial gamma dose rates. Radioisotope activity concentrations were determined by gamma spectrometry. Calculated gamma dose rates ranged from 56 to 193 nGy·h−1. Results indicated that the lifetime effective dose of the inhabitants of Chihuahua City is on average 19.8 mSv, resulting in a lifetime cancer risk of 0.001. In addition, the mean of the activity concentrations in soil were 52, 73 and 1097 Bq·kg−1, for 226Ra, 232Th and 40K, respectively. From the analysis, the spatial distribution of 232Th, 226Ra and 40K is to the north, to the north-center and to the south of city, respectively. In conclusion, the natural background gamma dose received by the inhabitants of Chihuahua City is high and mainly due to the geological characteristics of the zone. From the radiological point of view, this kind of study allows us to identify the importance of manmade environments, which are often highly variable and difficult to characterize.

  11. Authenticity test in ceramics and archaeological figures by thermoluminescence; Prueba de Autenticidad en ceramicas y figuras arqueologicas por termoluminiscencia

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez L, A.; Schaaf, P. [Laboratorio de Termoluminiscencia, Instituto de Geofisica-UNAM (Mexico); Filloy, L. [Museo Nacional de Antropologia e Historia, Ciudad de Mexico (Mexico)

    1999-07-01

    At present exists quite a lot of false archaeological pieces which provokes doubts about the legitimacy of the pieces. In this work it is presented the Authenticity test by Thermoluminescence realized at the urn of the goddess 13 serpent of the zapotec culture of Oaxaca which is exposed in Mexico City. The original piece contains crystalline structures which present hardly the thermoluminescence phenomena by the presence of {sup 238} U, {sup 232} Th, and {sup 40} K getting with this the form and intensity of the natural thermoluminescence curve of an archaeological piece which shows a Tl peak and allows to know so if it was made recently or not. (Author)

  12. Consistency among integral measurements of aggregate decay heat power

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, H.; Sagisaka, M.; Oyamatsu, K.; Kukita, Y. [Nagoya Univ. (Japan)

    1998-03-01

    Persisting discrepancies between summation calculations and integral measurements force us to assume large uncertainties in the recommended decay heat power. In this paper, we develop a hybrid method to calculate the decay heat power of a fissioning system from those of different fissioning systems. Then, this method is applied to examine consistency among measured decay heat powers of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U and {sup 239}Pu at YAYOI. The consistency among the measured values are found to be satisfied for the {beta} component and fairly well for the {gamma} component, except for cooling times longer than 4000 s. (author)

  13. Evaluation of the natural radioactivity at sands of anomalous regions of Espirito Santo state, Brazil; Avaliacao da radioatividade natural em areias de regioes anomalas do Espirito Santo, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Aquino, Reginaldo Ribeiro de; Pecequilo, Brigitte Roxana Soreanu, E-mail: raquino@ipen.b, E-mail: brigitte@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-10-26

    The natural radioactivity in sands of anomalous regions of the state of Espirito Santo, Brazil, were calculated from the concentration of activity of {sup 40}K, {sup 225}Ra and {sup 232}Th for the places of south and central of Camburi, Curva da Jurema, Ilha do Boi, Setibinha, south and central area of Praia da Areia Preta, denominated Black Spot. The samples were sealed and measured by high resolution gamma spectrometry and after a expectation time pf 30 days, until to reach a radioactive equilibrium

  14. Influence of nuclear dissipation on fission dynamics of the excited nucleus $^{248}$Cf within a stochastic approach

    Indian Academy of Sciences (India)

    ESLAMIZADEH HADI

    2016-07-01

    A stochastic approach to fission dynamics based on two-dimensional Langevin equations was applied to calculate the anisotropy of the fission fragments angular distribution and average pre-scission neutron multiplicities for the compound nucleus 248Cf formed in the $${16}$O+$^{232}$Th reactions. Postsaddle nuclear dissipation strength of $(12–14) \\times 10^{21} s^{−1}$ was extracted for Cf nucleus by fitting the results of calculations with the experimentaldata. Furthermore, it was found that the results of calculations for the anisotropy of the fission fragments angular distribution and pre-scission neutron multiplicities are very sensitive to the magnitude of post-saddle nucleardissipation.

  15. Measurements of natural radionuclides in soil samples from Upper Egypt

    Institute of Scientific and Technical Information of China (English)

    Shaban Ramadan Mohamed HARB; Khaled SALAHEL DIN; Abd Elbaset ABBADY; Mohamed Abd Elleh ALI; Rolf MICHEL

    2008-01-01

    This paper presents the results of natural radioactivity measured for the soil of Qena using gamma-ray spectrometry at ZSR, Hanover University, Germany. Soil samples of radioactive concentrations of 238U-series (234Th,214Pb, and 214Bi), 232Th-series (228Ac, 212pb, and 208Tl) and 40K were analyzed. Three objectives were set: (1) activity levels by surface soil sampling at 0~30 cm depth, (2) dose rates of gamma radiation, radium equivalent, index hazard, and effective dose, and (3) ambient dose rates.

  16. Estimation of radiation hazard indices from natural radioactivity of some rocks

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Different samples of igneous and metamorphic rocks from Egypt and Germany have been considered to measure γ-ray activity concentrations due to naturally occurring, potentially hazardous radonuclides 2266Ra, 232Th and 40K. The radiation hazard parameters including radiation equivalent activity, gamma-absorbed dose rate, and external and internal hazard indices have been estimated. The gamma-absorbed dose rates in air of rocks in Egypt range found that the radiation hazard indices in common igneous rocks are distinctly higher in acidic than in ultrabasic rocks. The results are discussed and compared with the corresponding published data.

  17. Radiation hazard of solid metallic tailings in Shangluo, China

    OpenAIRE

    Zhuang Sukai; Lu Xinwei; Li Jiantao; Li Qian

    2016-01-01

    The radiation hazards of five kinds of different solid metallic tailings collected from Shangluo, China were determined on the basis of natural radioactivity measurements using low background multichannel gamma ray spectrometry. The activity concentration of 226Ra, 232Th and 40K in the tailings ranged from 5.1 to 204.3, 3.8 to 28.5, and 289.6 to 762.3 Bq/kg, respectively. The radium equivalent activities and the external hazard indexes of all studied metall...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-11-15

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

  19. Transport of radionuclides in an unconfined chalk aquifer inferred from U-series disequilibria

    Science.gov (United States)

    Hubert, Amélie; Bourdon, Bernard; Pili, Eric; Meynadier, Laure

    2006-11-01

    U-series disequilibria measured in waters and rocks from a chalk aquifer in France have been used as an analog for long-term radionuclide migration. Drill core samples from a range of depths in the vadose zone and in the saturated zone, as well as groundwater samples were analyzed for 238U, 234U, 232Th and 230Th to determine transport mechanisms at the water/rock interface and to quantify parameters controlling the migration of radionuclides. Isotope measurements in rocks were done by TIMS, whereas ( 234U/ 238U) and ( 230Th/ 232Th) activity ratios in water samples were measured by multi-collector-ICP-MS. Both depletion and enrichment in 234U relative to 238U were observed in carbonate rock samples resulting from chemical weathering in the unsaturated zone and calcite precipitation in the zone of water-table oscillation, respectively. The correlation between ( 230Th/ 232Th) activity ratios and 87Sr/ 86Sr ratios found in the chalk samples indicates that thorium is mainly contained in a minor silicate phase whose abundance is variable in chalk samples. Water samples are all characterized by ( 234U/ 238U) > 1 resulting from α-recoil effect of 234Th. Groundwaters are characterized by a more radiogenic signature in 87Sr/ 86Sr than the rocks. Moreover, ( 230Th/ 232Th) activity ratios in the waters are lower than in the rocks, and increase with distance from the water divide, which suggests that Th transport is controlled by colloids formed during water infiltration in the soil. A 1-D transport model has been developed in order to constrain the U-series nuclide transport considering a transient behavior of radionuclides in the aquifer and a time-dependent composition for the solid phase. This model permits a prediction of the time scale of equilibration of the system, and an estimation of parameters such as weathering rate, distribution coefficients and α-recoil fractions. Retardation factors of 10-35 and from 1 × 10 4 to 2 × 10 5 were predicted for U and Th

  20. Determination of thorium in environmental and workplace materials by ICP-MS.

    Science.gov (United States)

    Holmes, L; Pilvio, R

    2000-01-01

    The paper outlines the advantages of the use of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) over radiometric techniques to measure natural thorium, 232Th. Experimental parameters that must be taken into account in the sample digestion, preparation and ICP-MS analysis of environmental (soils, rocks, sediments) or workplace (thorium oxide, reference solutions) materials are described. The methods presented are applied to various reference materials, with the aim of providing suitable procedures to be useful for other important thorium containing materials (such as monazite sands or welding electrodes). The participation in a European Commission intercomparison exercise is detailed and a comparison with alpha spectrometry is made.

  1. Natural radioactivity level of associated bone-coal mining area in Zhejiang Province

    Institute of Scientific and Technical Information of China (English)

    YE Ji-Da; ZHENG Hui-Di; SONG Wei-Li; ZENG Guang-Jian; WANG Sha-Ling; WU Zong-Mei

    2005-01-01

    The geographic distribution, γ-radiation level and specific activity of radionuclides of the bone-coal mines in Zhejiang Province were reported. The weighted average of γ-radiation dose rate of the bone-coal mines is 566 nGy/h for 107 main bone-coal mines. The weighted mean activity of 238U, 226Ra, 232Th and 40K in the samples are 949, 918, 34 and 554 Bq/kg for 171 samples of bone-coal, respectively.

  2. Radioactivity level of the ambient environment of Anren bone-coal power station

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The radioactivity level of the ambient environment of Anren Bonc-coalPower Station (BCPS) was investigated systematically. The γ radiation dose ratelevel in the environment, the content of 238U and 226Ra in the ambient soil and thefarmland in the direction of downwind, the concentrations of 238U, 232Th, 226Ra, 40Kand 222Rn, as well as α potential energy in air, and the concentrations of natural Uand Th in effluent are all higher than the corresponding values of the reference site.The additional annual effective dose equivalent to the residents living in the housesmade of bone-coal cinder brick is 2.7mSv.

  3. Spallation Neutron Spectrum on a Massive Lead/Paraffin Target Irradiated with 1 GeV Protons

    CERN Document Server

    Adam, J; Barashenkov, V S; Brandt, R; Golovatiouk, V M; Kalinnikov, V G; Katovsky, K; Krivopustov, M I; Kumar, V; Kumawat, H; Odoj, R; Pronskikh, V S; Solnyshkin, A A; Stegailov, V I; Tsoupko-Sitnikov, V M; Westmeier, W

    2004-01-01

    The spectra of gamma-ray emitted by decaying residual nuclei, produced by spallation neutrons with (n, xn), (n,xnyp), (n,p), (n,gamma) reactions in activation threshold detectors - namely, ^{209}Bi, ^{197}Au, ^{59}Co, ^{115}In, ^{232}Th, were measured in the Laboratory of Nuclear Problems (LNP), JINR, Dubna, Russia. Spallation neutrons were generated by bombarding a 20 cm long cylindrical lead target, 8 cm in diameter, surrounded by a 6 cm thick layer of paraffin moderator, with a 1 GeV proton beam from the Nuclotron accelerator. Reaction rates and spallation neutron spectrum were measured and compared with CASCADE code calculations.

  4. Dose assessment from domestic building materials used in housing sector in Serbia.

    Science.gov (United States)

    Petrović, M; Vučić, D; Karamarković, J

    2014-11-01

    The results of mass activity measuring in many domestic building materials used in a housing sector are presented. Natural radionuclides (40)K, (226)Ra, (232)Th, (235)U and (238)U as well as artificial radionuclide (137)Cs were detected using a gamma spectrometry. Based on measured mass activity values, the absorbed dose rate from examined building materials was calculated following EC standards. According to the UNSCEAR procedure, the annual effective dose was also calculated. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Natural radioactivity in some building materials in Cuba and their contribution to the indoor gamma dose rate

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-07-01

    The natural radioactivity of some building materials commonly used in Cuba was measured by gamma spectrometry. Typical concentrations, so far encountered, are in the ranges: 47 to 2511 Bq.kg{sup -1} for {sup 40} K; 9 to 71 Bq.kg{sup -1} for {sup 226} Ra; and 2 to 38 Bq.kg{sup -1} for {sup 232} Th. The external gamma ray absorbed doses in indoor air, and the corresponding effective dose equivalents in a typical dwelling are presented in this work. (author)

  6. Environmental Radioactivity Study in Surface Sediments of Guacanayabo Gulf (Cuba)

    Science.gov (United States)

    Reyes, H.; López-Pino, N.; Rizo, O. Díaz; Bernal, J. L.; D'Alessandro, K.; Padilla, F.; Corrales, Y.; Casanova, O. A.; Gelen, A.; Martínez, Y.; Aguilar, J.; Arado, J. O.; Maidana, N. L.

    2009-06-01

    Sediment samples have been collected in the Guacanayabo gulf located in the southeast Cuba, to determinate the radioactivity levels of 210Pb, 234Th, 214Pb, 137Cs, 232Th and 40K using Low-Background Gamma Spectrometry and to evaluate its impact in the habitat of important marine species for fishery industry. The obtained results show the lowest radioactivity levels determined in Cuban marine environments. The species capture declination in the last years is not originated by radioactive pollution of the zone.

  7. GEMS: Underwater spectrometer for long-term radioactivity measurements

    OpenAIRE

    2010-01-01

    GEMS (Gamma Energy Marine Spectrometer) is a prototype of an autonomous radioactivity sensor for underwater measurements, developed in the framework of the KM3NeT Design Study (DS) EC project. The spectrometer is sensitive to gamma rays produced by 40K decays and it is also able to detect other natural (e.g., 238U, 232Th) and anthropogenic radionuclides (e.g. 137Cs). The decay of 40K, contained in sea salt, particulate and sediments, is one of the main sources of photon background...

  8. (n,xn γ reaction cross section measurements for (n,xn reaction studies

    Directory of Open Access Journals (Sweden)

    Rouki Chariklia

    2013-03-01

    Full Text Available In the context of improvement of nuclear data bases for future nuclear reactor researches, we study (n,xn reactions experimentally with the help of the (n,xn γ technique. The experiments are performed at the GELINA facility which delivers a pulsed, white neutron beam. Several measurement campaigns have been performed on 235U, 232Th, 182,183,184,186W and 238U isotopes. A compilation of all these experimental cross sections (mostly still preliminary compared to theoretical predictions will be discussed.

  9. Fragment properties from fission of {sup 234,238}U induced by 6 -10 MeV bremsstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Goeoek, Alf; Eckardt, Christian; Enders, Joachim; Freudenberger, Martin; Neumann-Cosel, Peter von [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); Hambsch, Franz-Josef; Oberstedt, Stephan [EC-JRC IRMM, Geel (Belgium); Oberstedt, Andreas [Akademi foer Naturvetenskap och Teknik, Oerebro Universitet (Sweden); Fundamental Fysik, Chalmers Tekniska Hoegskola, Goeteborg (Sweden); Richter, Achim [Institut fuer Kernphysik, Technische Universitaet Darmstadt (Germany); ECT, Villazzano (Trento) (Italy)

    2012-07-01

    Experiments to investigate the photon-induced fission of actinide nuclei at excitation energies in the vicinity of the fission barrier are carried out at the super conducting Darmstadt linear electron accelerator S-DALINAC. A twin Frisch grid ionization chamber is used to deduce mass, total kinetic energy, and angular distributions of the fission fragments. In this contribution results on fission fragment mass and total kinetic energy distributions from {sup 234,238}U are presented along with the currently on-going investigation of {sup 234}U and {sup 232}Th fragment angular distributions.

  10. 钍俘获反应率离线伽马测量方法%Thorium capture ratio determination throughγ-ray off-line method∗

    Institute of Scientific and Technical Information of China (English)

    羊奕伟; 刘荣; 严小松

    2013-01-01

      为了测定聚变-裂变反应堆模型钍包层中的钍俘获率以及钍–铀转化率,探索了一种新的钍活化离线γ测量法.利用测量232Th俘获反应产物233Th衰变链中233Pa衰变放出的311.98 keV特征γ射线,来反推计算并最终确定232Th(n,γ)233Th的反应率,测试实验中不确定度约6%(233Th/232Th量级为10−17情况下).详细介绍了此方法的背景和原理方法,并进行简单的校验实验,证明其能够较好地得到模拟装置中的俘获率.与瞬发γ测量法以及质谱分析法进行对比,本方法更适合用于聚变-裂变反应堆模型钍包层中的钍俘获率以及钍-铀转化率测量,并有望进一步测量其他相关参数.%To determine the thorium capture ratio and thorium-uranium conversion ratio in the thorium cladding of the fusion-fission reactor model, a new approach, activated thorium sample decay γ-ray off-line measurement, is introduced in this paper. This method is based on the measurement of the 311.98 keV characteristic decayγ-ray emitted by 233Pa which is produced through decay of 233Th, the capture product of 232Th. Then some reverse mathematic approach is brought in and finally the 232Th (n,γ) 233Th reaction ratio is determined, with an uncertainty of 6%in the test experiment (233Th/232Th under the order of magnitude 10−17). In the paper, we introduce the detail of the approach including the background, principle and the result of a simple test experiment which shows that this approach can work well in thorium capture ratio determination. Compared with promptγ-ray method and mass spectrometer method, this decayγ-ray off-line method has many advantages in determining the thorium capture ratio and thorium-uranium conversion ratio in the thorium cladding. It is also promising in the measurement of other relevant parameters.

  11. The efficiency study of different purification methods for liquid scintillator

    CERN Document Server

    Hu, Wei; Yu, Boxiang; Zhang, Xuan; Zhou, Li; Cai, Xiao; Sun, Lijun

    2016-01-01

    JUNO is an experiment aimed at detecting neutrino mass hierarchy. The innermost part of the JUNO detector is formed by 20,000 tons of liquid scintillator which should have very low level of radioactive materials, such as 238U, 232Th, and 40K. Since the radioactive level of raw LAB(the solvent of LS)cannot reach so stringent requirements of JUNO, the purification for LAB plays an extremely important role in LS production. This article studies the efficiency of several different purification methods for LS, like distillation, water extraction and Al2O3 purification.

  12. Application of pulse shape discrimination in Si detector for fission fragment angular distribution measurements

    Indian Academy of Sciences (India)

    B K Nayak; E T Mirgule; R K Choudhury

    2005-12-01

    Pulse shape discrimination (PSD) with totally depleted transmission type Si surface barrier detector in reverse mount has been investigated to identify fission fragments in the presence of elastic background in heavy ion-induced fission reactions by both numerical simulation and experimental studies. The PSD method is compared with the other conventional methods adopted to identify fission fragments with solid-state detectors such as - telescope and single thin detector and the data for the 10B + 232Th fission reaction are presented. Results demonstrate the usefulness of a single transmission-type surface barrier detector for the identification of fission fragments and projectiles like heavy ions.

  13. High-spin states in boson models with applications to actinide nuclei

    CERN Document Server

    Kuyucak, S

    1995-01-01

    We use the 1/N expansion formalism in a systematic study of high-spin states in the sd and sdg boson models with emphasis on spin dependence of moment of inertia and E2 transitions. The results are applied to the high-spin states in the actinide nuclei ^{232}Th, ^{234-238}U, where the need for g bosons is especially acute but until now, no realistic calculation existed. We find that the d-boson energy plays a crucial role in description of the high-spin data.

  14. Natural radioactivity measurements in building materials used in Samsun, Turkey.

    Science.gov (United States)

    Tufan, M Çagatay; Disci, Tugba

    2013-01-01

    In this study, radioactivity levels of 35 different samples of 11 commonly used building materials in Samsun were measured by using a gamma spectrometry system. The analysis carried out with the high purity Germanium gamma spectrometry system. Radioactivity concentrations of (226)Ra, (232)Th and (40)K range from 6 to 54 Bq kg(-1), 5 to 88 Bq kg(-1) and 6 to 1070 Bq kg(-1), respectively. From these results, radium equivalent activities, gamma indexes, absorbed dose rates and annual effective doses were calculated for all samples. Obtained results were compared with the available data, and it was concluded that all the investigated materials did not have radiological risk.

  15. Radioactivity in food in Belgrade city

    OpenAIRE

    Vitorović Gordana; Mitrović Branislava; Grdović Svetlana; Petrujkić Branko; Vitorović Duško

    2010-01-01

    The activity concentrations of 40K, 238U, 226Ra, 232Th and 137Cs were measured using the gamma spectrometric method in different food chain samples from the area of the City of Belgrade during the periods May-June 2007 and May-June 2008. Relatively high activities of 40K and 137Cs were detected in the soil. These results indicate that 137Cs is present in the area of Belgrade even 20 years after the nuclear accident in the Chernobyl nuclear power plant. However, in the samples of feedstuffs, a...

  16. Vertical profiles and enrichment pattern of natural radionuclides in monazite areas of coastal Kerala

    Energy Technology Data Exchange (ETDEWEB)

    Shetty, P.K. [Department of Studies in Physics, Mangalore University, Mangalagangothri, Mangalore, Karnataka 574199 (India); Narayana, Y. [Department of Studies in Physics, Mangalore University, Mangalagangothri, Mangalore, Karnataka 574199 (India)]. E-mail: narayanay@yahoo.com; Siddappa, K. [Department of Studies in Physics, Mangalore University, Mangalagangothri, Mangalore, Karnataka 574199 (India)

    2006-07-01

    Detailed studies on radionuclides concentration in different environmental matrices of high background areas were undertaken in the coastal areas of Karunagapalli, Chavara, Neendakara and Kollam to study the distribution and enrichment of the radionuclides in the region. The sand samples collected at different distances from sea waterline and at different depths, were analysed for primordial radionuclides by gamma spectrometry. The activity of primordial radionuclides was determined for the different size fractions of sand to study the enrichment pattern. The highest activity was found confined in 125-63 {mu}m particle size fraction in sand. The minimum {sup 232}Th activity was 9.4 Bq kg{sup -1}, found in Kollam at a depth of 10-20 cm, 40 m away from waterline in 500-250 {mu}m particle size fraction and maximum activity of 136,811.2 Bq kg{sup -1} was observed in Chavara in grains of size 125-63 {mu}m at a depth of 0-10 cm for a sample collected 20 m away from waterline. The lowest {sup 226}Ra activity observed was 29.6 Bq kg{sup -1} at Kollam beach for a sample 40 m away from waterline in grains of size 1000-500 {mu}m and at a depth of 20-30 cm and the highest activity observed was 10,309 Bq kg{sup -1} in grains of size 125-63 {mu}m for a sample collected at a distance 20 m away from waterline and at a depth of 0-10 cm. The activity of {sup 4}K was below detectable level in most of the samples collected from the high background monazite area. The {sup 232}Th, {sup 226}Ra activities decrease with depth for the samples collected 20 m away from the waterline and increase with depth for the samples collected 40 m away from the waterline at Chavara and Kollam beaches. No definite correlation was found between variation of the concentrations of {sup 232}Th and {sup 226}Ra with depth at Karunagapalli and Neendakara beach sands. There exists a strong correlation between {sup 226}Ra and {sup 232}Th activities in the region. The results of these investigations are presented

  17. Evaluation of Radioactivity Concentration in Tilapia Nilotica and Radiation Dose to Egyptian Population

    Science.gov (United States)

    Amer, Hannan H.; El-Khawas, Enas H.

    2013-03-01

    One of the three goals of the United Nations for sustainable food security is to ensure that all people have access to sufficient, nutritionally adequate, and safe food. The study was carried out to evaluate the Uranium (238U) and thorium (232Th) concentration in the Bolti (Tilapia nilotica) fish collected from Nasser Lake by using two different types of detectors CR-39 SSNTDs and gamma spectroscopy. The annual intake of Bolti fish was estimated on the basis of their average annual consumption. Calculations were also made to determine the effective dose to an individual consuming such diet.

  18. Geo-neutrino review

    Energy Technology Data Exchange (ETDEWEB)

    Tolich, N., E-mail: ntolich@u.washington.edu [Center for Experimental Nuclear Physics and Astrophysics, and Departments of Physics, University of Washington, Seattle, WA, 98195 (United States)

    2012-08-15

    The principal source of energy for dynamic processes of the earth, such as plate tectonics is thought to come from the radioactive decays of {sup 238}U, {sup 232}Th, and {sup 40}K within the earth. These decays produce electron-antineutrinos, so-called geo-neutrinos, the measurement of which near the earth's surface allows for a direct measure of the total radiogenic heat production in the earth. The KamLAND and Borexino experiments have both measured a geo-neutrino flux significantly greater than zero. As shown in these proceedings, more precise future measurements will significantly constrain earth composition models.

  19. Internal exposure from building materials exhaling (222)Rn and (220)Rn as compared to external exposure due to their natural radioactivity content.

    Science.gov (United States)

    Ujić, Predrag; Celiković, Igor; Kandić, Aleksandar; Vukanac, Ivana; Durasević, Mirjana; Dragosavac, Dusan; Zunić, Zora S

    2010-01-01

    The main scope of this paper is to point out the importance of introducing radon and thoron exhalation measurements from building materials in the regulating frame. Currently (2009), such a regulation of this kind of exposure is not explicitly included in the Serbian regulating network. To this end, this work reports concentration measurements of (226)Ra, (232)Th and (40)K and radon and thoron exhalation rates from building materials used in Serbia. Following detailed analysis, it was noticed that both internal exposures to radon and/or thoron exhaling from building materials may exceed external exposures to their precursors contained therein.

  20. Fast Thorium Molten Salt Reactors started with Plutonium

    OpenAIRE

    Merle-Lucotte, E.; Heuer, D.; Le Brun, C.; Mathieu, L.; Brissot, R.; Liatard, E.; Méplan, O.; Nuttin, A.

    2006-01-01

    One of the pending questions concerning Molten Salt Reactors based on the 232Th/233U fuel cycle is the supply of the fissile matter, and as a consequence the deployment possibilities of a fleet of Molten Salt Reactors, since 233U does not exist on earth and is not yet produced in the current operating reactors. A solution may consist in producing 233U in special devices containing Thorium, in Pressurized Water or Fast Neutrons Reactors. Two alternatives to produce 233U are examined here: dire...