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Sample records for 232th 237np 231pa

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2009-10-01

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

  6. 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...

  7. 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.

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

    Science.gov (United States)

    Yücel, Haluk

    2007-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-11-15

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

  10. In-beam spectroscopy of 231Pa

    International Nuclear Information System (INIS)

    Information on energy levels and on E2 and M1 matrix elements in 231Pa has been obtained using conversion-electron and gamma-ray spectroscopy following the 232Th(p, 2p)231Pa reaction and Coulomb excitation of the radioactive target 231Pa by 4He and 32S ions. The results are analyzed in the framework of the rotational model, applied to the rotational band built on the 1/2-[530] Nilsson state whose 3/2- member forms the ground state of this nucleus. The deviations of the level energies from the rigidrotor values can be described by Coriolis couplings. The analysis of the Coulomb-excitation process shows that a constant set of rotational parameters Q0, gR, gK, and b can fairly well account for the measured line intensities. (orig.)

  11. 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.

  12. Chemical aspects of 237 Np Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    The 237Np Moessbauer effect has been especially useful in studies of neptunium chemistry, by virtue of its excellent resolution and straightforward experimental techniques. Neptunium can have valences from +3 to +7, and a broad range of compounds can be prepared that are analogous to those of other actinide elements. Studies on neptunium compounds, for example, have a ready application to the analogous compounds of uranium and plutonium. The emphasis in this paper will be on the application of the 237Np Moessbauer effect to problems in neptunium chemistry

  13. Irradiation studies of 231Pa in DHRUVA reactor for preparation of 232U

    International Nuclear Information System (INIS)

    In this paper, identification of the potential source of 231Pa, various stages of its recovery and the sample of 231Pa supplied for trial irradiation are described. For producing 232U, irradiation work is proposed in different stages of irradiation. Various trial irradiations and its results are discussed in this paper along with their specific objectives. A computational estimation of conversion efficiency of 231Pa (∼ 10μg) to 232U in DHRUVA reactor, was carried out. The computational result predicted the conversion efficiency and the results of γ-spectroscopy based analysis of the second trial sample matched well. A first level calculation was also carried out to estimate the tolerable quantity of 232Th to keep the concentration of 233U below 5% in the 232U sample. The radioactivity due to the presence of various impurities present in the sample, during the high fluence irradiation, is being estimated. The feasibility of production of the 232U isotope in DHRUVA reactor has thus been established. (author)

  14. 232Th, a rigid rotor

    International Nuclear Information System (INIS)

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

  15. Determination of 237Np in sediments and sea water

    International Nuclear Information System (INIS)

    Compared to other transuranic elements such as Pu and Am present environmental levels of Np are very low. Neptunium nuclides are therefore of little radiological significance in the concentrations found in the environment. In the longer term, however, 237Np will become one of the most important radionuclides remaining in high-level radioactive waste. We have further developed a new method for analysis of neptunium in large samples of soil, sediment and seawater. The samples are measured on alpha detectors and by ICPMS (Inductively coupled plasma mass spectrometry)

  16. 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)

  17. 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

  18. Pre-concentration studies of 237Np using sulphonic acid based actinide™ resin

    International Nuclear Information System (INIS)

    The absorption studies of the standard 237Np have been performed using actinide™ resin to standardise the selective separation. The supernatant solution was checked for alpha activity of 237Np using scintillation counting technique. It was found that more than 95 % of 237Np was absorbed in the actinide™ resin. The absorbed 237Np from the actinide™ resin was leached out using isopropyl alcohol. The leached out activity of 237Np in the isopropyl alcohol was estimated using same alpha scintillation counting technique and was found to be greater than 95 %. The selective absorption of 237Np resin from the other impurities in actinide™ is helpful in the analytical solution during recycle of fuels as well as in the waste management process. This is very much important because 237Np is one of the long-lived minor actinides produced from the 238U(n, 2n) reaction followed by beta decay. Thus it is useful for the conventional reactor based on natU and fast reactor based on U-Pu fuel. (author)

  19. Status of the Neutron Capture Measurement on 237Np with the DANCE Array at LANSCE

    International Nuclear Information System (INIS)

    Neptunium-237 is a major constituent of spent nuclear fuel. Estimates place the amount of 237Np bound for the Yucca Mountain high-level waste repository at 40 metric tons. The Department of Energy's Advanced Fuel Cycle Initiative program is evaluating methods for transmuting the actinide waste that will be generated by future operation of commercial nuclear power plants. The critical parameter that defines the transmutation efficiency of actinide isotopes is the neutron fission-to-capture ratio for the particular isotope in a given neutron spectrum. The calculation of transmutation efficiency therefore requires accurate fission and capture cross sections. Current 237Np evaluations available for transmuter system studies show significant discrepancies in both the fission and capture cross sections in the energy regions of interest. Herein we report on 237Np (n,γ) measurements using the recently commissioned DANCE array

  20. 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...... efficiency in terms of chemical yields of 237Np and removal of interfering nuclides. Although ca. 30% of sorbed Np onto AG 1-×4 was stripped out during HCl rinsing step for the removal of Th, chemical yield ratios of 237Np to 242Pu were proven steady with an average value of 0.67±0.04 (n=15) under selected......, thereby demonstrating the usefulness of 242Pu as a non-isotopic tracer for 237Np chemical yield monitoring. The on-column separation procedure fosters rapid analysis as required in emergency situations since each individual sample can be handled within 2.5h, and leads to a significant decrease in labor...

  1. (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.

  2. New radiochemical methods for determination of 237Np a 241Pu using extraction chromatography (Presentation)

    International Nuclear Information System (INIS)

    Thesis was focused on the development of a new methodology for the separation of anthropogenic transuranium radionuclides 237Np a 241Pu from different kinds of matrices. The analytical methods used in this study were based on extraction chromatography and were optimized according to the sample type. The proposed radiochemical procedure is a combination of two algorithms, which represent the separation of radionuclides by using extraction chromatographic sorbents TEVA resin and TRU resin supplied by Eichrom Technologies LLC. 239Np a 237Np were selectively captured on sorbent TEVA resin in oxidation state 4+. TRU resin was used for purification of plutonium fraction from interfering americium radionuclide. 242Pu and 239Np radionuclides as tracers have been used to monitor the radiochemical yields of separation. Before every radiochemical separation tracer radionuclide 239Np was obtained by separation from the parent radionuclide 243Am, which is in radioactive equilibrium to 239Np. The average yield of chemical separation was 69,3% for 239Np at 277 keV energy line and 65,9% at 228 keV energy line. The NPL AH-B08069 (2008) samples which consist of the mixture of alpha-radionuclides were used for the modification and optimization of separation method used for separation of Np and Pu in model samples. This method provided high radiochemical yields of 239,240Pu (95,0 ± 3,5)% and 237Np (87,9 ± 3,0)%.. Reliability of the method was verified by applying our modified separation procedures on reference materials IAEA-375 and IAEA-414 supplied by International Atomic Energy Agency. A good agreement between the results is obtained by this procedure and the certified values were found. Samples of contaminated soils from the area of Nuclear power plant A-1 Jaslovske Bohunice which is stored temporarily before disposal were analyzed using developed separation procedure. Specific activity of investigated radionuclides was determined in these samples. (author)

  3. New radiochemical methods for determination of 237Np a 241Pu using extraction chromatography

    International Nuclear Information System (INIS)

    Thesis was focused on the development of a new methodology for the separation of anthropogenic transuranium radionuclides 237Np a 241Pu from different kinds of matrices. The analytical methods used in this study were based on extraction chromatography and were optimized according to the sample type. The proposed radiochemical procedure is a combination of two algorithms, which represent the separation of radionuclides by using extraction chromatographic sorbents TEVA resin and TRU resin supplied by Eichrom Technologies LLC. 239Np a 237Np were selectively captured on sorbent TEVA resin in oxidation state 4+. TRU resin was used for purification of plutonium fraction from interfering americium radionuclide. 242Pu and 239Np radionuclides as tracers have been used to monitor the radiochemical yields of separation. Before every radiochemical separation tracer radionuclide 239Np was obtained by separation from the parent radionuclide 243Am, which is in radioactive equilibrium to 239Np. The average yield of chemical separation was 69,3% for 239Np at 277 keV energy line and 65,9% at 228 keV energy line. The NPL AH-B08069 (2008) samples which consist of the mixture of alpha-radionuclides were used for the modification and optimization of separation method used for separation of Np and Pu in model samples. This method provided high radiochemical yields of 239,240Pu (95,0 ± 3,5)% and 237Np (87,9 ± 3,0)%.. Reliability of the method was verified by applying our modified separation procedures on reference materials IAEA-375 and IAEA-414 supplied by International Atomic Energy Agency. A good agreement between the results is obtained by this procedure and the certified values were found. Samples of contaminated soils from the area of Nuclear power plant A-1 Jaslovske Bohunice which is stored temporarily before disposal were analyzed using developed separation procedure. Specific activity of investigated radionuclides was determined in these samples. (author)

  4. Study of 237Np photonuclear reactions near threshold, induced by gamma rays from thermal neutron capture

    International Nuclear Information System (INIS)

    The photodisintegration of 237Np has been studied using monochromatic photons produced by thermal neutron capture in several materials. The partial cross sections σ gamma, sub(f) and σ gamma, sub(n) were measured in the energy interval from 5.43 MeV to 10.83 MeV. Analysing the photofission data according to the liquid drop model, the height (E sub(f)) and the curvature ((h/2π)ω) of the simple fission barrier were determined: E sub(f) = (5.9 +- 0.2) MeV and (h/2π)ω = (0.8 +- 0.4) MeV. For the competition between photoneutron emission and fission (GAMMA sub(n) / GAMMA sub(f) a constant value was found (1.28+- 0.15) in the energy range 6.73 - 10.83 MeV. From this result the following nuclear temperatures for 237Np were extracted on bases of some models of levels density: T = 0.84 +- 0.06 MeV (Fujimoto-Yamaguchi model) and T = 0.60 +- 0.04 MeV (Constant Nuclear temperature model). (Author)

  5. Study of the excited levels of 233Pa by the 237Np alpha decay

    International Nuclear Information System (INIS)

    The excited levels in 233Pa following the 237Np alpha decay have been studied, by performing different experiences to complete available data and supply new information. Thus, two direct alpha spectrum measurement, one alpha-gamma bidimensional coincidence experiment, three gamma-gamma and gamma-X ray coincidences and some other measurements of the gamma spectrum, direct and coincident with alpha-particles have been made. These last experiences have allowed to obviate usual radiochemical separation methods, the 233Pa radioactive descendent interferences being eliminated by means of the coincidence technic. As a result, a primary decay scheme has been elaborated, including 15 new gamma transitions and two new levels, not observed in the most recent works. (Author) 60 refs

  6. 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.

  7. 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.)

  8. 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)

  9. 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)

  10. 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)

  11. 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.

  12. 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

  13. 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.

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

    International Nuclear Information System (INIS)

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

  15. Uranium age determination: Separation and analysis of 230Th and 231Pa

    International Nuclear Information System (INIS)

    In this work we focused on the age determination of uranium materials of different uranium enrichment. The radioactive decay of the uranium isotopes provides a chronometer that is inherent to the material, in particular the mother/daughter pairs 234U/230Th and 235U/231Pa can be advantageously used. Due to the relatively long half-lives of 234U (2.46 · 105 years) and 235U (7.04 · 108 years) only minute amounts of daughter nuclides are growing in, therefore both separation of Th and Pa from uranium must be of high chemical recovery and must afford large decontamination factors. Analytical methods for the age determination of uranium samples using the parent/daughter relations 234U/230Th and 235U/231Pa is demonstrated. Thorium is separated from bulk uranium using extraction chromatography and subsequently quantified using square-spectrometry, thermal ionisation mass spectrometry (TIMS) and inductively coupled mass spectrometry (ICP-MS). Protactinium is separated by highly selective sorption of protactinium to silica gel followed by square-spectrometric quantification. The methods were tested and validated using uranium reference materials of different uranium enrichment and of known ages. The experimental results obtained with both methods were found to agree with the assumed ages of the reference materials within the combined uncertainty of the measurement. The analysis exploiting the parent/daughter pair 235U/231Pa exhibits a slightly larger combined uncertainty and bias than the thorium method but is found valuable in validating the experimental results by means of a second, independent analysis

  16. The rotational bands in the nuclei 229Pa and 231Pa

    International Nuclear Information System (INIS)

    Experimental evidence is presented for the similarity between the rotational spectra built on the 1/2-[530] state in 231Pa, where the 3/2- member of the band forms the ground state, and in 229Pa, where this state lies within 20 keV of the ground state. Our findings are in contrast with earlier work invoking octupole deformations in the ground state to account for the different positions of low-lying Nilsson states in the two isotopes. (author)

  17. Inductively Coupled Plasma Mass Spectrometry For The Determination Of 237Np In Spent Nuclear Fuel Samples By Isotope Dilution Method Using 239Np As A Spike

    International Nuclear Information System (INIS)

    A determination method for 237Np in spent nuclear fuel samples was developed using an isotope dilution method with 239Np as a spike. In this method, inductively coupled plasma mass spectrometry (ICP-MS) was taken for the 237Np instead of the previously used alpha spectrometry. 237Np and 239Np were measured by ICP-MS and gamma spectrometry, respectively. The recovery yield of 237Np in synthetic samples was 95.9±9.7% (1S, n=4). The 237Np contents in the spent fuel samples were 0.15, 0.25, and 1.06 μg/mgU and these values were compared with those from ORIGEN-2 code. A fairly good agreement between the measurements (m) and calculations (c) was obtained, giving ratios (m/c) of 0.93, 1.12 and 1.25 for the three PWR spent fuel samples with burnups of 16.7, 19.0, and 55.9 GWd/MtU, respectively

  18. Rapid determination of 237Np in soil samples by multi-collector inductively-coupled plasma mass spectrometry and gamma spectrometry

    International Nuclear Information System (INIS)

    A radiochemical procedure is developed for the determination of 237Np in soil with multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS) and gamma-spectrometry. 239Np (milked from 243Am) was used as an isotopic tracer for chemical yield determination. The neptunium in the soil is separated by thenoyl-trifluoracetone extraction from 1 M HNO3 solution after reducing Np to Np(IV) with ferrous sulfamate, and then purified with Dowex 1 x 2 anion exchange resin. 239Np in the resulting solution is measured with gamma-spectrometry for chemical yield determination while the 237Np is measured with MC-ICP-MS. Measurement results for soil samples are presented together with those for two reference samples. By comparing the determined value with the reference value of the 237Np activity concentration, the feasibility of the procedure was validated. (author)

  19. Fusion hybrids for generation of advanced (231Pa+232U+233U+234U)-fuel in closed (U-Pu-Th)-fuel cycle

    International Nuclear Information System (INIS)

    Technology of controlled thermonuclear fusion (CTF) is traditionally regarded as a practically inexhaustible energy source. However, development, mastering, broad deployment of fast breeder reactors and closure of nuclear fuel cycle (NFC) can also extend fuel base of nuclear power industry (NPI) up to practically unlimited scales. Under these conditions, it seems reasonable to introduce into a circle of the CTF-related studies the works directed towards solving some principal problems which can appear in a large-scale NPI in closed NFC. The first challenge is a large scale of operations in NFC back-end that should be reduced by achieving substantially higher fuel burn-up in power nuclear reactors. The use of 231Pa-232Th-232U-233U fuel in light-water reactor (LWR) opens a possibility of principle to reach very high (about 30% HM) or even ultra-high fuel burn-up. The second challenge is a potential unauthorized proliferation of fissionable materials. As is known, a certain remarkable quantity of 232U being introduced into uranium fraction of nuclear fuel can produce a serious barrier against switching the fuel over to non-energy purposes. Involvement of hybrid thermonuclear reactors (HTR) into NPI structure can substantially facilitate resolving these problems. If HTR will be involved into NPI structure, then main HTR mission consists not in energy generation but in production of nuclear fuel with a certain isotope composition. The present paper analyzes some neutron-physical features in production of advanced nuclear fuels in thorium HTR blankets. The obtained results demonstrated that such a nuclear fuel may be characterized by very stable neutron-multiplying properties during full LWR operation cycle and by enhanced proliferation resistance too. The paper evaluates potential benefits from involvement of HTR with thorium blanket into the international closed NFC. (author)

  20. 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...

  1. Synchronous 231Pa/230Th Holocene variability from the Mendeleev and Lomonosov Ridges at mid-depths

    Science.gov (United States)

    Hoffmann, S. S.; McManus, J. F.; Curry, W. B.; Brown-Leger, S.

    2011-12-01

    The Arctic Ocean contributes to global thermohaline circulation through export of intermediate and deep water through Fram Strait; however, the history of formation and circulation of Arctic waters at these depths is little known and presents a major challenge to paleoceanographers. Sedimentary measurements of the uranium-series radionuclides 231Pa and 230Th may provide a means of investigating the past dynamics of these deeper waters. We present 231Pa/230Th records from two well-dated box cores at mid-depths in the Arctic: PL-AR-94 BC 17 from 2255 m on the flank of the Mendeleev Ridge, Makarov Basin, and PL-94-AR BC 28 from 1990 m on the Lomonosov Ridge flank, Amundsen Basin. These records show synchronous millennial-scale variability through the Holocene, with peaks in 231Pa/230Th at 10.5, 7, and 5 ka, interspersed with low ratio values at 8, 6, and 4 ka. Indicators of surface ocean processes at these sites, such as particle fluxes and planktonic δ18O, do not show similar synchronous variation; nor do 231Pa/230Th records from shallower and deeper waters in the central Arctic. We therefore hypothesize that these millennial-scale variations in 231Pa/230Th ratios reflect paleoceanographic changes specific to mid-depth waters across Arctic subbasins, and that these common features may reflect a common source in the core flow of the Arctic Ocean Boundary Current between 1500 and 2500 m.

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

    International Nuclear Information System (INIS)

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

  3. Uranium age determination - Separation and analysis of 230Th and 231Pa

    International Nuclear Information System (INIS)

    Full text: In recent years several incidents involving illicit trafficking and smuggling of nuclear material, radioactive sources and radioactively contaminated materials have raised growing public concern about criminal acts involving nuclear materials. Consequently, research efforts in nuclear forensic science have been intensified in order to develop and improve methods for the identification of the nature and origin of seized materials. Information obtained from the analysis of unknown nuclear materials is of key importance in order to aide authorities that are in charge of developing fast and appropriate response action. For the identification of nuclear materials various sample characteristics are of relevance, including isotopic composition, the content of chemical impurities, material properties and the date of production. Information on the production date, respectively the 'age' of nuclear materials, will also be of key importance in other fields of nuclear science, i.e. for the verification of a Fissile Materials Cut-Off Treaty (FMCT) in order to distinguish freshly produced materials from 'old' excess weapons materials. The age of nuclear materials may also be of relevance under a strengthened safeguards regime to reveal clandestine production of weapons usable materials, i.e. the separation of plutonium or production of highly enriched uranium (HEU). The age dating of plutonium samples has been described in detail for bulk samples as well as for particles. In this work we focused on the age determination of uranium materials of different uranium enrichment. The radioactive decay of the uranium isotopes provides a chronometer that is inherent to the material, in particular the mother/daughter pairs 234U/230Th and 235U/231Pa can be advantageously used. Due to the relatively long half-lives of 234U (2.46·105 years) and 235U (7.04·108 years) only minute amounts of daughter nuclides are growing in, therefore both separation of Th and Pa from uranium must

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2011-04-01

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

  6. Coulex fission of 234U, 235U, 237Np, and 238Np studied within the SOFIA experimental program

    International Nuclear Information System (INIS)

    SOFIA (Studies On FIssion with Aladin) is an experimental project which aims at systematically measuring the fission fragments' isotopic yields as well as their total kinetic energy, for a wide variety of fissioning nuclei. The PhD work presented in this dissertation takes part in the SOFIA project, and covers the fission of nuclei in the region of the actinides: 234U, 235U, 237Np and 238Np. The experiment is led at the heavy-ion accelerator GSI in Darmstadt, Germany. This facility provides intense relativistic primary beam of 238U. A fragmentation reaction of the primary beam permits to create a secondary beam of radioactive ions, some of which the fission is studied. The ions of the secondary beam are sorted and identified through the FR-S (Fragment Separator), a high resolution recoil spectrometer which is tuned to select the ions of interest.The selected - fissile - ions then fly further to Cave-C, an experimental area where the fission experiment itself takes place. At the entrance of the cave, the secondary beam is excited by Coulomb interaction when flying through an target; the de-excitation process involves low-energy fission. Both fission fragments fly forward in the laboratory frame, due to the relativistic boost inferred from the fissioning nucleus.A complete recoil spectrometer has been designed and built by the SOFIA collaboration in the path of the fission fragments, around the existing ALADIN magnet. The identification of the fragments is performed by means of energy loss, time of flight and deviation in the magnet measurements. Both fission fragments are fully (in mass and charge) and simultaneously identified.This document reports on the analysis performed for (1) the identification of the fissioning system, (2) the identification of both fission fragments, on an event-by-event basis, and (3) the extraction of fission observables: yields, TKE, total prompt neutron multiplicity. These results, concerning the actinides, are discussed, and the

  7. Rapid determination of 237Np in soil samples by multi-collector inductively-coupled plasma mass spectrometry and gamma spectrometry

    OpenAIRE

    Yi, Xiaowei; Shi, Yanmei; Xu, Jiang; He, Xiaobing; ZHANG, HAITAO; Lin, Jianfeng

    2013-01-01

    A radiochemical procedure is developed for the determination of 237Np in soil with multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS) and gamma-spectrometry. 239Np (milked from 243Am) was used as an isotopic tracer for chemical yield determination. The neptunium in the soil is separated by thenoyl-trifluoracetone extraction from 1 M HNO3 solution after reducing Np to Np(IV) with ferrous sulfamate, and then purified with Dowex 1 × 2 anion exchange resin. 239Np in the resu...

  8. 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.

  9. The neutron capture cross sections of {sup 237}Np(n,{gamma}) and {sup 240}Pu(n,{gamma}) and its relevance in the transmutation of nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

    Neutron capture cross sections of actinides are of great relevance for the Transmutation of Nuclear Waste in Accelerator Driven Systems (ADS) and Generation-IV reactors. The neutron capture cross sections of {sup 237}Np and {sup 240}Pu in the range of 1 eV to 2 keV were measured at the n-TOF facility with a Total Absorption Calorimeter. The data have been analyzed with the SAMMY code. The corresponding covariance matrices have been generated. The final cross sections are presented and compared to the previously existing ones.The n-TOF {sup 237}Np {sigma}(n,{gamma}) is in agreement with the evaluated data files below 300 eV and its is lower by 10 to 15% up to 2 keV. This discrepancy with the evaluated data files is also observed in the capture cross section derived from the transmission measurements of Gressier et al. In the case of the {sup 240}Pu {sigma}(n,{gamma}), the n-TOF {sigma}(n,{gamma}) agrees within uncertainties with JENDL-3.3 and JEFF-3.1, except for a group of resonances around 800 eV. Endf/B-VII data are lower than n-TOF and the mentioned evaluations, with differences that increase with neutron energy up to 15-20 per cent.

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

    CERN Document Server

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

    2001-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-03-01

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

  12. 230,232Th in milk, meat, and grain in Korea

    International Nuclear Information System (INIS)

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

  13. 232Th and 238U neutron emission cross section calculations and analysis of experimental data

    International Nuclear Information System (INIS)

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

  14. Analysis of prompt fission neutron spectrum and multiplicity for 237Np(n,f)in the frame of multi-modal Los Alamos model

    Institute of Scientific and Technical Information of China (English)

    Zheng Na; Ding Yi; Zhong Chun-Lai; Chen Jin-Xiang; Fan Tie-Shuan

    2009-01-01

    The improved version of Los Alamos model with the multi-modal fission approach is used to analyse the prompt fission neutron spectrum and multiplicity for the neutron-induced fission of 237Np.The spectra of I~eutrons emitted from fragments for the three most dominant fission modes(standard Ⅰ,standard Ⅱ and superlong)are calculated separately and the total spectrum is synthesized.The multi-modal parameters contained in the spectrum model are determined on the basis of experimental data of fission fragment mass distributions.The calculated total prompt fission neutron spectrum and multiplicity are better agreement with the experimental data than those obtained from the conventional treatment of the Los Alamos model.

  15. 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.

  16. 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.

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

    International Nuclear Information System (INIS)

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

  18. 226Ra, 232Th and 40K analysis in water samples from Assiut, Egypt

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  20. 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.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  3. Sequential leaching extraction of 239,240Pu, 238Pu, 241Pu, 237Np and 241Am from a mud sample: An intercomparison study

    International Nuclear Information System (INIS)

    The transuranics content of a mud sample taken from a nuclear waste storage container was analysed employing two different sequential extraction methods. The following fractions were isolated: (1)Water soluble (2) Readily available (3) Carbonate bound and specifically adsorbed (4) Organically bound (5) Oxide and hydroxides bound and (6) residual. Both methods differ in the reagents employed, the extraction sequence applied as well as the temperature and means of extraction. The 239,240Pu, 238Pu, 237Np and 241Am extracted in each phase were determined using standard radiochemical procedures. 241Pu was analysed through the 241Am in-growth on just one old disk of the residual fraction containing plutonium. Plutonium was mainly associated to organic-oxides fractions (89-92 %). The percentage extracted in each fraction depended on the method and the extraction sequence used. The soluble fraction of plutonium was less than 13%. Neptunium seemed to be the more soluble than the other transuranics (27%) and the americium showed a tendency to be associated to carbonates (30%). (author)

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

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

  7. Evaluation and improvement of cross section accuracy for most important dosimetry reactions 27Al(n,p), 56Fe(n,p) and 237Np(n,f) including covariance data

    International Nuclear Information System (INIS)

    New evaluations of cross sections and their uncertainties for dosimetry reactions 27Al(n,p) , 56Fe(n,p) and 237Np(n,f) have been carried out in the frame work of IAEA Research Contract No. 11372/RB. Data files prepared for this reactions in the ENDF-6 format may be consider as candidates for the new International Reactor Dosimetry File: IRDF-2002. (author)

  8. 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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-05-01

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

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

    Science.gov (United States)

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

    2012-02-01

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

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

    Science.gov (United States)

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

    2006-09-01

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

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

    OpenAIRE

    Xin Wang; Qiyan Feng; Ruoyu Sun; Guijian Liu

    2015-01-01

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

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

    Science.gov (United States)

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

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

  15. 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.

  16. 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.

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

    Science.gov (United States)

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

    2016-08-01

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

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

    Science.gov (United States)

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

    1997-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    CERN Document Server

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

    2012-01-01

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

  1. 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...

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

    International Nuclear Information System (INIS)

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

  3. The nuclear structure of 229Pa from the 231Pa(p,t)229Pa and 230Th(p,2nγ)229Pa reactions

    International Nuclear Information System (INIS)

    The level structure of the 229Pa nucleus has been investigated by means of the 231Pa(p,t)229Pa and 230Th(p,2nγ)229Pa reactions. Triton angular-distribution measurements were subjected to a CCBA analysis and combined with the results of in-beam conversion electron and γ-ray spectroscopy to establish a level scheme. Two low-lying bands of opposite parity were observed up to spins (23/2)- and (17/2)+, respectively. Rotational bands built on some 0+ excitations of the even-even core can be assigned. The lowest states of three further low-lying bands are observed. The level scheme is interpreted in terms of an octupole-deformed core with an unpaired proton. From the E1/E2 branching ratio the electric dipole moment can be deduced vertical stroke D0vertical stroke =(0.09 ±0.04) e .fm. ((orig.))

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

    International Nuclear Information System (INIS)

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

  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. 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...

  7. 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.

  8. 238U, 232TH, AND 222RN concentration measured in various traditional medicinal plant preparation using nuclear track detectors

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  10. 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)

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

    Science.gov (United States)

    Badhan, K; Mehra, R

    2012-11-01

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

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

    International Nuclear Information System (INIS)

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

  13. 8Dim calculations of the third barrier in $^{232}$Th and a conflict between theory and experiment on uranium nuclei

    CERN Document Server

    Jachimowicz, P; Skalski, J

    2013-01-01

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

  14. 237Np在破碎凝灰岩和凝灰质砂上的吸附研究%STUDY OF 237Np ADSORPTION ON CRUSHED TUFF AND TUFFACEOUS SAND

    Institute of Scientific and Technical Information of China (English)

    王旭东; 田中忠夫; 武部慎一

    2001-01-01

    The adsorption characteristics of 237Np on crushed tuff andtuffaceous sand from northeast Japan have been studied using sequential extraction analysis technique. With a large difference in cation exchange capacity (CEC), both materials show nearly same sorptivity for 237Np. Together with dominance of ion exchange processes in sorption indicated by sequential extraction analysis, it suggests an absence of specific sorption at sites of this kind. It's interesting to find that sorption on Fe-Mn oxyhydroxide-oxides, defined by our sequential extraction procedure, almost keep constant for both cases, without time dependency. A potential mechanism of surface chemical reaction is deduced. Kinetics with respect to exchangeable and residual portions in tuff and fuffaceous sand confirms that some slow processes are controlling radionuclide sorption.%用连续提取法研究了237Np在破碎凝灰岩和凝灰质砂上的吸附。研究结果表明,48h以后,2种介质对237Np的吸附百分数相近,而且吸附的237Np在各相间的分布均以离子交换态为主。凝灰岩和凝灰质砂的阳离子交换容量差异显著,说明离子交换作用仅发生在粘土矿物的表面,凝灰岩中蒙脱石的层间没有发生阳离子交换。在28d的实验时间内,237Np在介质中的Fe-Mn氧化物-氢氧化物上的吸附百分数几乎不随时间变化。这可能是因为该吸附过程为瞬时即可完成的表面化学反应。介质内离子交换相和残余相上的吸附则显示为缓慢的吸附过程。

  15. 230Th/ 234U/ 238U and 231Pa/ 235U ages from a single fossil coral fragment by multi-collector magnetic-sector inductively coupled plasma mass spectrometry

    Science.gov (United States)

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

    2005-02-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  18. 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.

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

    OpenAIRE

    SALEH, Ibrahim Hindawy

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Čučulović Ana

    2014-01-01

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

  4. 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.

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

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hansen, Violeta; Hou, Xiaolin;

    2012-01-01

    The environmental mobility and bioavailability of radionuclides are related to their physicochemical forms, namely species. We here present a speciation analysis of important radionuclides including 129I (also 127I), 137Cs, 232Th, 238U and plutonium isotopes (239Pu and 240Pu) in soil (IAEA-375...

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

    International Nuclear Information System (INIS)

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

  7. 230Th, 232Th and 238U determinations in phosphoric acid fertilizer and process products by ICP-MS

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-10-01

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

  9. 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

  10. 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%

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Mohammed Saad Alsaffar

    2015-07-01

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

  15. 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)

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-04-15

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-02-15

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

  1. 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

  2. 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.

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

    International Nuclear Information System (INIS)

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

  4. 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.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Oliveira Luciano S.R.

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  9. High-temperature X-ray diffraction studies on La1-2xCaxThxPO4(s) (x = 0, 0.25, 0.5) solid-solution

    International Nuclear Information System (INIS)

    Advanced Heavy Water Reactor (AHWR), Compact High Temperature Reactor (CHTR) and Accelerator Driven System (ADS) are being developed in India to use 232Th-233U fuel cycle. Unlike natural uranium, natural thorium contains only trace amounts of fissile material (231Th), which are insufficient to initiate a nuclear chain reaction. It can be used with 233U, 235U and 239Pu as fissile fuel. Because of it, the back end of thorium fuel cycle contains long-lived 231Pa, 229Th, 230Th and low level of minor actinides (237Np, 241Am, 243Am, 244Cm) for final disposal in geological repositories. From a geochemical point of view, monazite (LnPO4 with Ln: rare earths) is the most abundant lanthanide phosphate observed in natural samples). Such minerals appear as the major thorium source on earth, especially in several ores which contain up to 29 wt% of ThO2, 16wt% of UO2, respectively

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-06-12

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

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-01-15

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  20. 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 .

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Victor M. Tshivhase

    2015-12-01

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

  3. 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)

  4. 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

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

    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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  8. {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)

  9. 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).

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

    International Nuclear Information System (INIS)

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

  11. 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.

  12. 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.

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

    Science.gov (United States)

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

    2016-06-01

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

  14. 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})

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  18. 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.

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

    Science.gov (United States)

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

    2015-10-01

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

  20. 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.

  1. 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)

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  6. 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

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

    Science.gov (United States)

    Turner, Simon; Black, Stuart; Berlo, Kim

    2004-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-09-01

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

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

    Science.gov (United States)

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

    2008-09-01

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

  10. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-07-01

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

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

    Science.gov (United States)

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

    2016-02-01

    Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland. PMID:26490904

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  17. 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)

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

    Science.gov (United States)

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

    2016-01-01

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

  19. Characterization of actinide physics specimens for the US/UK joint experiment in the Dounreay Prototype Fast Reactor

    International Nuclear Information System (INIS)

    The United States and the United Kingdom are engaged in a joint research program in which samples of the higher actinides are irradiated in the Dounreay Prototype Fast Reactor in Scotland. The purpose of the porogram is (1) to study the materials behavior of selected higher actinide fuels and (2) to determine the integral cross sections of a wide variety of the higher actinide isotopes. Samples of the actinides are incorporated in fuel pins inserted in the core. For the fuel study, the actinides selected are 241Am and 244Cm in the form of Am2O3, Cm2O3, and Am6Cm(RE)7O21, where (RE) represents a mixture of lanthanides. For the cross-section determinations, the samples are milligram quantities of actinide oxides of 248Cm, 246Cm, 244Cm, 243Cm, 243Am, 241Am, 244Pu, 242Pu, 241Pu, 240Pu, 239Pu, 238Pu, 237Np, 238U, 236U, 235U, 234U, 233U, 232Th, 230Th, and 231Pa encapsulated in vanadium. Coincident with the irradiations, neutron flux and energy spectral measurements are made with vanadium-encapsulated dosimeter materials located within the same fuel pins

  20. Preparation of actinide specimens for the US/UK joint experiment in the Dounreay Prototype Fast Reactor

    International Nuclear Information System (INIS)

    A joint research program involving the United States and the United Kingdom was initiated about four years ago for the purpose of studying the fuel behavior of higher actinides using in-core irradiation in the fast reactor at Dounreay, Scotland. Simultaneously, determination of integral cross sections of a wide variety of higher actinide isotopes (physics specimens) was proposed. Coincidental neutron flux and energy spectral measurements were to be made using vanadium encapsulated dosimetry materials in the immediate region of the fuel pellets and physics samples. The higher actinide samples chosen for the fuel study were 241Am and 244Cm in the forms of Am2O3, Cm2O3, and Am6Cm(RE)7O21, where (RE) represents a mixture of lanthanides. Milligram quantities of actinide oxides of 248Cm, 246Cm, 244Cm, 243Cm, 243Am, 241Am, 244Pu, 242Pu, 241Pu, 240Pu, 239Pu, 238Pu, 237Np, 238U, 236U, 235U, 234U, 233U, 232Th, 230Th, and 231Pa were encapsulated to obtain nuclear cross section and reaction rate data for these materials

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

    International Nuclear Information System (INIS)

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

  2. 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.

  3. Speciation of 241Am molecular compounds through 237Np Moessbauer and 241Am XPS spectroscopy

    International Nuclear Information System (INIS)

    Light actinides (U to Am) can be found in several oxidation states from (II) to (VII) in the molecular form or in the condensed matter state. The large variety of oxidation states is usually attributed to the contribution of the 5f states to the valence orbitals. For the heavier actinides, for which the 5f electrons are non bonding, the actinides become rare-earth like with a smaller number of oxidation states (II and III). However it is still not understood what really decides on the stability of a given oxidation state, and how it is depending on the chemical environment (coordination sphere, nature of the counter-anion, etc). This work shows how Moessbauer spectroscopy and 4f photoelectron spectroscopy (XPS) can contribute to progress in the understanding of the electronic structure of the actinide, especially for Am compounds Moessbauer reverse experiments were undertaken to show in what manner the electronic structure of the Am is preserved during the decay process (oxidation state stability). The result of XPS measurements shows that it is possible to correlate the 4f binding energy of the Am to the charge at the actinide core. The obtained results are somewhat surprising. The formal oxidation state (V) is 'less oxidised' than expected. Some Am(III) have less electron density (that means are more ionic) than americyl (V) hydroxide or carbonate. The reason for these surprisingly results comes from the 'Am=O' multiple bond system which reduces dramatically the charge at the actinide by a pi-donation mechanism. The evolution of the 4f binding energy of the Am species does not follow the oxidation state order. Theoretical DFT calculation were done on Am(V) compounds for qualitative electronic modeling. (authors)

  4. 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

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

    Institute of Scientific and Technical Information of China (English)

    羊奕伟; 刘荣; 蒋励; 鹿心鑫; 王玫; 严小松

    2014-01-01

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

  6. 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.

  7. 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

  8. Sorption of 231Pa on silica and the effect of humic acid

    International Nuclear Information System (INIS)

    Sorption of protactinium on silica colloids was studied in the pH range of 1 to 12 in NaClO4 medium using radiotracer technique. Silica was characterized using X-ray diffraction, light scattering and surface area measurements. The point of zero charge for silica colloids was about pH 2. The sorption of protactinium was about 98% in the pH range of 3 to 9 and was lower (70-80 %) below pH 3 and above pH 9. The quantitative sorption in the pH range 3 to 9 could be explained by surface complexation model. The reduction in sorption was attributed to electrostatic repulsion as the fraction of protactinium exists as cationic species at pH ≤ 2 and anionic species above pH 9. There was reduction in the sorption of protactinium in the presence of humic acid below pH 2 and above pH 10. Sorption of protactinium on silica in presence of 0.05M HF was about 99% between pH 3 to 8 and below 30% in the low and high pH region. Isotherm study revealed an exponential decrease in protactinium activity in solution with increase in silica. (author)

  9. Speciation of {sup 241}Am molecular compounds through {sup 237}Np Moessbauer and {sup 241}Am XPS spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fouchard, S.; Gouder, T.; Colineau, E.; Wastin, F.; Rebizant, J.; Simoni, E.; Guillaumont, D.; Meyer, D

    2004-07-01

    Light actinides (U to Am) can be found in several oxidation states from (II) to (VII) in the molecular form or in the condensed matter state. The large variety of oxidation states is usually attributed to the contribution of the 5f states to the valence orbitals. For the heavier actinides, for which the 5f electrons are non bonding, the actinides become rare-earth like with a smaller number of oxidation states (II and III). However it is still not understood what really decides on the stability of a given oxidation state, and how it is depending on the chemical environment (coordination sphere, nature of the counter-anion, etc). This work shows how Moessbauer spectroscopy and 4f photoelectron spectroscopy (XPS) can contribute to progress in the understanding of the electronic structure of the actinide, especially for Am compounds Moessbauer reverse experiments were undertaken to show in what manner the electronic structure of the Am is preserved during the decay process (oxidation state stability). The result of XPS measurements shows that it is possible to correlate the 4f binding energy of the Am to the charge at the actinide core. The obtained results are somewhat surprising. The formal oxidation state (V) is 'less oxidised' than expected. Some Am(III) have less electron density (that means are more ionic) than americyl (V) hydroxide or carbonate. The reason for these surprisingly results comes from the 'Am=O' multiple bond system which reduces dramatically the charge at the actinide by a pi-donation mechanism. The evolution of the 4f binding energy of the Am species does not follow the oxidation state order. Theoretical DFT calculation were done on Am(V) compounds for qualitative electronic modeling. (authors)

  10. Transmutation study of 237Np in energy + transmutation setup using 1.6 GeV deuteron-beam

    International Nuclear Information System (INIS)

    In this paper, the results of the measurement of cross sections of (n, γ) and (n, f) reactions of long lived fission fragment, Np237 have been presented in the mixed neutron environment of the E + T set up

  11. 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....

  12. 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...

  13. 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.

  14. 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.)

  15. Photofission of heavy nuclei at energies up to 4 GeV

    CERN Document Server

    Cetina, C; Briscoe, W J; Cole, P L; Feldman, G; Heimberg, P; Murphy, L Y; Phillips, S; Sanabria, J C; Crannell, H; Longhi, A; Sober, D I; Kezerashvili, G Ya; Crannell, Hall

    2000-01-01

    Total photofission cross sections for 238U, 235U, 233U, 237Np, 232Th, and natPb have been measured simultaneously, using tagged photons in the energy range Egamma=0.17-3.84 GeV. This was the first experiment performed using the Photon Tagging Facility in Hall B at Jefferson Lab. Our results show that the photofission cross section for 238U relative to that for 237Np is about 80%, implying the presence of important processes that compete with fission. We also observe that the relative photofission cross sections do not depend strongly on the incident photon energy over this entire energy range. If we assume that for 237Np the photofission probability is equal to unity, we observe a significant shadowing effect starting below 1.5 GeV.

  16. Solid state track recorder measurements in the poolside critical assembly

    International Nuclear Information System (INIS)

    Fission rate measurements using solid state track recorders (SSTR) have been performed at the PCA. A schematic representation of a cross-section of the PCA is shown. Fission rates were measured in the pressure vessel simulator at the T/4, T/2 and 3T/4 positions and in the void box (VB). SSTR measurements were carried out with 232Th, 235U (bare and cadmium covered), 238U and 237Np fissionable deposits. Midplane only measurements were carried out for 235U and 237Np, while 5 axial locations at 1/4T and 1/2T and 3 axial locations at 3/4T and in the VB were sampled for 232Th and 238U. The HEDL SSTR fission rate measurements reported herein for both configurations together with NBS and CEN/SCK fission chamber measurements will be used to establish absolute and relative fission reaction rates, and ratios for the PCA pressure vessel Benchmark Facility

  17. Translation of selected papers published in Nuclear Constants, No. 3(57), Moscow 1984

    International Nuclear Information System (INIS)

    The document contains the English translation of 6 papers selected for the nuclear data interest, (mainly the determination and the evaluation of the fast fission cross sections of 232Th, 235U, 238U, 237Np, 243Am) which were published in ''Topics in Atomic Science and Technology'', Series Nuclear Constants, No. 3(57), Moscow (1984). The original report was distributed as INDC(CCP)-240/G. Refs, figs and tabs

  18. FFTF (FAST FLUX TEST FACILITY) REACTOR CHARACTERIZATION PROGRAM ABSOLUTE FISSION RATE MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    FULLER JL; GILLIAM DM; GRUNDL JA; RAWLINS JA; DAUGHTRY JW

    1981-05-01

    Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.

  19. FFTF (Fast Flux Test Facility) Reactor Characterization Program: Absolute Fission-rate Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, J.L.; Gilliam, D.M.; Grundl, J.A.; Rawlins, J.A.; Daughtry, J.W.

    1981-05-01

    Absolute fission rate measurements using modified National Bureau of Standards fission chambers were performed in the Fast Flux Test Facility at two core locations for isotopic deposits of {sup 232}Th, {sup 233}U, {sup 235}U, {sup 238}U, {sup 237}Np, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu. Monitor chamber results at a third location were analyzed to support other experiments involving passive dosimeter fission rate determinations.

  20. Isoscaling and fission modes in the yields of the Kr and Xe isotopes from photofission of actinides

    Science.gov (United States)

    Drnoyan, J.; Zhemenik, V. I.; Mishinsky, G. V.

    2016-05-01

    Yields of Kr and Xe isotopes in photofission of 232Th, 238U, 237Np, 244Pu, 243Am, and 248Cm were tested for isoscaling dependence. Isoscaling for Kr is revealed. For Xe, isoscaling is found to be affected by the STI and STII fission modes governed by the N = 82 and N = 88 neutron shells. The work was performed at the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (JINR).

  1. Analysis for the radionuclides of the natural uranium and thorium decay chains with special reference to uranium mine tailings

    International Nuclear Information System (INIS)

    A detailed review is made of the experimental techniques that are available, or are in the process of development, for the determination of 238U, 235U, 234U, 231Pa, 232Th, 230Th, 228Th, 228Ra, 226Ra, 223Ra, 210Po and 210Pb. These products of the uranium and thorium decay chains are found in uranium mine tailings. Reference is also made to a procedure for the selective phase extraction of mineral phases from uranium mine tailings

  2. 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.

  3. Radiochemical method for the simultaneous determination of 233U, 236U, 237Np, 236Pu, 238Pu, and 239Pu in biological materials

    International Nuclear Information System (INIS)

    A radiochemical method has been developed for the determination of multiple isotopes of uranium, neptunium, and plutonium in biological materials. The elements are separated from the other sample constituents and from each other by anion exchange in halide media. Their recoveries are monitored by isotopic diluents. The amounts of the analyte and diluent isotopes of each element are measured alpha spectrometrically. The interelemental separation factors are generally greater than 102, and the recovery of each element ranges from 60% to 90%. 4 references, 1 table

  4. 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)

  5. On the role of energy separated in fission process, excitation energy and reaction channels effects in the isomeric ratios of fission product 135Xe in photofission of actinide elements

    Science.gov (United States)

    Thiep, Tran Duc; An, Truong Thi; Cuong, Phan Viet; Vinh, Nguyen The; Mishinski, G. V.; Zhemenik, V. I.

    2016-07-01

    In this work we present the isomeric ratio of fission product 135Xe in the photo-fission of actinide elements 232Th, 233U and 237Np induced by end-point bremsstrahlung energies of 13.5, 23.5 and 25.0 MeV which were determined by the method of inert gaseous flow. The data were analyzed, discussed and compared with the similar data from literature to examine the role of energy separated in fission process, excitation energy and reaction channels effects.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    A new certified reference material (CRM) for radionuclides in sea water from the Irish sea (IAEA-443) is described and the results of the certification process are presented. Ten radionuclides (3H, 40K, 90Sr, 137Cs, 234U, 235U, 238U, 238Pu, 239+240Pu and 241Am) have been certified, and information...... values on massic activities with 95% confidence intervals are given for four radionuclides (230Th, 232Th, 239Pu and 240Pu). Results for less frequently reported radionuclides (99Tc, 228Th, 237Np and 241Pu) are also reported. The CRM can be used for quality assurance/quality control of the analysis...

  7. Application of inductively coupled plasma mass spectrometry to the measurement of long-lived radionuclides in environmental samples

    International Nuclear Information System (INIS)

    This review describes applications of inductively coupled plasma mass spectrometry (ICP-MS) to the determination of long-lived radionuclides in environmental samples. Simultaneous determination of 232Th and 238U in biological samples is described in detail; in this procedure an internal standard, Tl or Bi, is adopted for correction of the matrix effect. Determination of 237Np in soil samples by ICP-MS is also described. It is chemically separated to ensure no interference from matrix elements. The detection limits are several mBq (several pg) for the case of radionuclides having a half life of thirty or forty thousand years. (author)

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

    OpenAIRE

    Шаманин, И.; Годовых, А.

    2006-01-01

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

  9. 238U And 232Th Concentration In Rock Samples using Alpha Autoradiography and Gamma Spectroscopy Techniques

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  12. Fission fragment angular distributions and fission cross section validation

    International Nuclear Information System (INIS)

    The present knowledge of angular distributions of neutron-induced fission is limited to a maximal energy of 15 MeV, with large discrepancies around 14 MeV. Only 238U and 232Th have been investigated up to 100 MeV in a single experiment. The n-TOF Collaboration performed the fission cross section measurement of several actinides (232Th, 235U, 238U, 234U, 237Np) at the n-TOF facility using an experimental set-up made of Parallel Plate Avalanche Counters (PPAC), extending the energy domain of the incident neutron above hundreds of MeV. 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. I will show the methods we used to reconstruct the full angular resolution by the tracking of fission fragments. Below 10 MeV our results are consistent with existing data. For example in the case of 232Th, below 10 MeV the results show clearly the variation occurring at the first (1 MeV) and second (7 MeV) chance fission, corresponding to transition states of given J and K (total spin and its projection on the fission axis), and a much more accurate energy dependence at the 3. chance threshold (14 MeV) has been obtained. In the spallation domain, above 30 MeV we confirm the high anisotropy revealed in 232Th by the single existing data set. I'll discuss the implications of this finding, related to the low anisotropy exhibited in proton-induced fission. I also explore the critical experiments which is valuable checks of nuclear data. The 237Np neutron-induced fission cross section has recently been 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 n-TOF data, we simulate a criticality experiment performed at Los Alamos with a 6 kg sphere of 237Np. This sphere was

  13. 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.

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

    International Nuclear Information System (INIS)

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

  15. Calculations of neutron and proton induced reaction cross sections for actinides in the energy region from 10MeV to 1GeV

    International Nuclear Information System (INIS)

    Several nuclear model codes were applied to calculations of nuclear data in the energy region from 10MeV to 1GeV. At energies up to 100MeV the nuclear theory code GNASH was used for nuclear data calculation for neutrons incident for on 238U, 233-236U, 238-242Pu, 237Np, 232Th, 241-243Am and 242-247Cm. At energies from 100MeV to 1GeV the intranuclear cascade exciton model including the fission process was applied to calculations of protons and neutrons with 233U, 235U, 238U, 232Th, 232Pa, 237Np, 238Np, 239Pu, 241Am, 242Am and 242-248Cm. Determination of parameter systematics was a major effort in the present work that was aimed at improving the predictive capability of the models used. An emphasis was placed upon a simultaneous analysis of data for a variety of reaction channels for the nuclei considered, as well as of data that are available for nearby nuclei or for other incident particles. Comparisons with experimental data available on multiple reaction cross sections, isotope yields, fission cross sections, particle multiplicities, secondary particle spectra, and double differential cross sections indicate that the calculations reproduce the trends, and often the details, of the measurements data. (author) 82 refs

  16. Total half-lives for selected nuclides

    International Nuclear Information System (INIS)

    Measurements of the half-lives of 3H, 10Be, 14C, 26Al, 40K, 39Ar, 53Mn, 87Rb, 92Nb, 129I, 138La, 147Sm, 176Lu, 174Hf, 180Ta, 187Re, 186Os, 190Pt, 204Pb, 210Pb, 210Po, 222Rn, 224Th, 226Ra, 227Ac, 228Ra, 228Th, 230Th, 232Th, 231Pa have been compiled and evaluated. The effect of the 14C half-life value on carbon dating ages is discussed as well as the stability of 204Pb. 237 refs., 30 tabs

  17. 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.

  18. ORELA contribution to thorium-cycle nuclear data

    International Nuclear Information System (INIS)

    The measurements of direct importance to the 232Th/233U 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 232Th 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 252Cf anti nu measurement of unprecedented accuracy and 233U anti nu ratio measurement give a 233U prompt anti nu (thermal) of 2.490 +- 0.009 neutron/fission. This result allows a much more satisfactory understanding of the 233U 2200 m/s constants. In addition, a 232Th γ-ray production measurement provides needed cross sections for shielding, and important data for both application and fission physics were obtained from 232Th fission and both 231Pa and 234U fission and total cross section measurements. Data requirements and discrepancies suggested from this work are discussed

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

    Science.gov (United States)

    Wilson, J. N.; Gunsing, F.; Bernstein, L.; Bürger, A.; Görgen, A.; Thompson, I. J.; Guttormssen, M.; Larsen, A.-C.; Mansouri, P.; Renstrøm, T.; Rose, S. J.; Siem, S.; Wiedeking, M.; Wiborg, T.

    2012-02-01

    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.

  20. 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.

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

    International Nuclear Information System (INIS)

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

  2. Improved radioanalytical method for the simultaneous determination of Th, U, Np, Pu and Am(Cm) on a single TRU column by alpha spectrometry and ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Macsik, Z.; Groska, J.; Vajda, N. [RadAnal Ltd., Budapest (Hungary); Vogt, S.; Kim, C.S.; Maddison, A.; Donohye, D. [IAEA, Seibersdorf (Austria). Environmental Sample Lab.; Kis-Benedek, G. [IAEA, Seibersdorf (Austria). Terrestrial Environment Lab.

    2013-05-01

    A radioanalytical method based on the use of a single TRU extraction chromatographic column and selective, on-column oxidation state adjustment of actinides was developed for the determination of Th, U, Np, Pu and Am(Cm) in environmental samples (such as sediment and swipe samples). The procedure of Vajda et al. was further investigated and optimized focusing on the separation of Th, U and Np. The improved method combines two measurement techniques - alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS) - which allows to obtain more reliable information on a wider range of isotopes: {sup 228}Th, {sup 230}Th, {sup 232}Th, {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 241}Am, {sup 242}Cm, {sup 243}Cm and {sup 244}Cm from one sample. (orig.)

  3. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Andrade-II, E.; Karapetyan, G.S.; Deppman, A.; Guimaraes, V. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Balabekyan, A.R. [Yerevan State University, Alex Manoogian 1, Yerevan (Armenia); Demekhina, N.A. [Yerevan Physics Institute, Alikhanyan Brothers 2, Yerevan (Armenia); Joint Institute for Nuclear Research (JINR), Flerov Laboratory of Nuclear Reactions (LNR), Moscow (Russian Federation)

    2014-07-01

    We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on {sup 241}Am, {sup 238}U, and {sup 237}Np targets and the Bremsstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on {sup 232}Th and {sup 238}U 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. (author)

  5. Improved radioanalytical method for the simultaneous determination of Th, U, Np, Pu and Am(Cm) on a single TRU column by alpha spectrometry and ICP-MS

    International Nuclear Information System (INIS)

    A radioanalytical method based on the use of a single TRU extraction chromatographic column and selective, on-column oxidation state adjustment of actinides was developed for the determination of Th, U, Np, Pu and Am(Cm) in environmental samples (such as sediment and swipe samples). The procedure of Vajda et al. was further investigated and optimized focusing on the separation of Th, U and Np. The improved method combines two measurement techniques - alpha spectrometry and inductively coupled plasma mass spectrometry (ICP-MS) - which allows to obtain more reliable information on a wider range of isotopes: 228Th, 230Th, 232Th, 234U, 235U, (236U), 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 241Am, 242Cm, 243Cm and 244Cm from one sample. (orig.)

  6. Application of high resolution inductively coupled plasma mass spectrometry to the measurement of long-lived radionuclides

    International Nuclear Information System (INIS)

    The radioactivity determination of long-lived radionuclides in environmental samples is difficult due to their low concentration and low specific activity. Limits of detection (DL) for long-lived radionuclides (99Tc, 226Ra, 232Th, 237Np, 238U, 243Am) in standard solutions using Inductively Coupled Plasma Mass Spectrometry with a double focusing mass analyzer (HR-ICP-MS) with ultrasonic nebulizer were calculated. DL of most nuclides were under the fg g-1 level. It seems that the analysis by using HR-ICP-MS has the advantage of detection for low level radio nuclides whole half life is more than 1000 y. This method was applied to 226Ra analysis in hot spring waters and 230Th in lake sediments analysis after a simple chemical separation. (author)

  7. 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.

  8. 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.)

  9. Radionuclide desorption kinetics on synthetic Zn/Ni-labeled montmorillonite nanoparticles

    Science.gov (United States)

    Huber, F. M.; Heck, S.; Truche, L.; Bouby, M.; Brendlé, J.; Hoess, P.; Schäfer, T.

    2015-01-01

    Sorption/desorption kinetics for selected radionuclides (99Tc(VII), 232Th(IV), 233U(VI), 237Np(V), 242Pu and 243Am(III)) under Grimsel (Switzerland) ground water conditions (pH 9.7 and ionic strength of ∼1 mM) in the presence of synthetic Zn or Ni containing montmorillonite nanoparticles and granodiorite fracture filling material (FFM) from Grimsel were examined in batch studies. The structurally bound Zn or Ni in the octahedral sheet of the synthetic colloids rendered them suitable as colloid markers. Only a weak interaction of the montmorillonite colloids with the fracture filling material occurs over the experimental duration of 10,000 h (∼13 months). The tri- and tetravalent radionuclides are initially strongly associated with nanoparticles in contrast to 99Tc(VII), 233U(VI) and 237Np(V) which showed no sorption to the montmorillonite colloids. Radionuclide desorption of the nanoparticles followed by sorption to the fracture filling material is observed for 232Th(IV), 242Pu and 243Am(III). Based on the conceptual model that the driving force for the kinetically controlled radionuclide desorption from nanoparticles and subsequent association to the FFM is the excess in surface area offered by the FFM, the observed desorption kinetics are related to the colloid/FFM surface area ratio. The observed decrease in concentration of the redox sensitive elements 99Tc(VII), 233U(VI) and 237Np(V) may be explained by reduction to lower oxidation states in line with Eh-pH conditions prevailing in the experiments and thermodynamic considerations leading to (i) precipitation of a sparingly soluble phase, (ii) sorption to the fracture filling material, (iii) possible formation of eigencolloids and/or (iv) sorption to the montmorillonite colloids. Subsequent to the sorption/desorption kinetics study, an additional experiment was conducted investigating the potential remobilization of radionuclides/colloids attached to the FFM used in the sorption/desorption kinetic

  10. Systematic study of actinide and pre-actinide fission modes

    CERN Document Server

    Andrade-II, E; Deppman, A; Bernal-Castillo, J L; Balabekyan, A R; Demekhina, N A; Adam, J; Garcia, F; Guzmán, F

    2016-01-01

    In this work, we present new experimental data on mass distribution of fission fragments from $^{241}$Am proton-induced fission at $660$ MeV measured at the LNR Phasotron (JINR). The systematic analysis of several measured fragment mass distributions from different fission reactions available in the literature is also presented. The proton-induced fission of $^{241}$Am, $^{237}$Np and $^{238}$U at 26.5, 62.9 and 660 MeV was studied. The proton-induced fission of $^{232}$Th was studied at 26.5, 62.9 and 190 MeV. The fission of $^{208}$Pb also by a proton was investigated at 190, 500 and 1000 MeV. The fission of $^{197}$Au was studied for 190 and 800 MeV protons. Bremsstrahlung reactions with maximum photon energies of 50 and 3500 MeV were studied for $^{232}$Th and $^{238}$U. The framework of the Random Neck Rupture Model was applied in the analysis. The roles of the neutron excess and of the so called fissility parameter were also investigated.

  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. Ternary fission with 4He emission in 16O(144 Mev) + 232Th and 12C(108 Mev) + 197Au reactions

    International Nuclear Information System (INIS)

    Results of coincidence study of 4He emission with fission fragments in 12C (108 MeV) ions with sup(197)Au target and 16O (144 MeV) ions with sup(223)Th target reactions are presented. On the basis of Monte Carlo kinematic simulation of nuclear reactions analysis of energy and velocity spectra of α-particles has been performed. The conclusion has been performed. The conclusion has been drawn that the main source of 4He emission was the evaporation from a fissioning compound nucleus. Substantial part of α-particles was emitted from fully accelerated fission fragments. Some of 4He nuclei with mean energy of about 16 MeV emitted mainly perpendicular to the fission axis were identified as similar to long range α-particles in ternary fission of heavy nuclei with low excitation energy. Multiplicities of emission of these particles are considerably higher than those at low excitation energy. Comparison of experimental results with statistical model calculations has been made

  13. Neutron capture cross section of $^{232}Th$ measured at the nTOF facility at CERN in the unresolved resonance region up to 1 MeV

    CERN Document Server

    Aerts, G; Alvarez, H; Alvarez-Velarde, F; Andriamonje, Samuel A; Andrzejewski, J; Assimakopoulos, P A; Audouin, L; Badurek, G; Baumann, P; Becvar, F; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Carillo de Albornoz, A; Cennini, P; Chepel, V Yu; Chiaveri, Enrico; Colonna, N; Cortés, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillman, I; Dolfini, R; Domingo-Pardo, C; Dridi, W; Durán, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Fitzpatrick, L; Frais-Kölbl, H; Fujii, K; Furman, W; Gonçalves, I; González-Romero, E M; Goverdovski, A; Gramegna, F; Griesmayer, E; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martínez, A; Igashira, M; Isaev, S; Jericha, E; Käppeler, F K; Kadi, Y; Karadimos, D; Karamanis, D; Kerveno, M; Ketlerov, V; Köhler, P; Konovalov, V; Kossionides, E; Krticka, M; Lamboudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marques, L; Marrone, S; Mastinu, P; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, Heinz; O'Brien, S; Oshima, M; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, Carlo; Rudolf, G; Rullhusen, P; Salgado, J; Sarchiapone, L; Savvidis, I; Stéphan, C; Taliente, G; Taín, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarín, D; Vincente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K

    2006-01-01

    We have measured the neutron capture reaction yield of /sup 232energy range from 1 eV to 1 MeV. The average capture cross section has been extracted in the energy range from 4 keV up to 1 MeV with an overall accuracy better than 4%. An independent IAEA evaluation shows good agreement with the data. The average cross section has been expressed in terms of average resonance parameters using the partial waves script l=0,1, and 2.

  14. 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.

  15. ZZ MATXSLIBJ33, JENDL-3.3 based, 175 N-42 photon groups (VITAMIN-J) MATXS library for discrete ordinates multi-group

    International Nuclear Information System (INIS)

    -156, Gd-152, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, Tb-159, Er-162, Er-164, Er-166, Er-167, Er-168, Er-170, Hf-174, Hf-176, Hf-177, Hf-178, Hf-179, Hf-180, Ta-181, W-182, W-183, W-184, W-186, Hg-196, Hg-198, Hg-199, Hg-200, Hg-201, Hg-202, Hg-204, Pb-204, Pb-206, Pb-207, Pb-208, Bi-209, Ra-223, Ra-224, Ra-225, Ra-226, Ac-225, Ac-226, Ac-227, Th-227, Th-228, Th-229, Th-230, Th-232, Th-233, Th-234, Pa-231, Pa-232, Pa-233, U-232, U-233, U-234, U-235, U-236, U-237, U-238, Np-235, Np-236, Np-237, Np-238, Np-239, Pu-236, Pu-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Pu-244, Pu-246, Am-241, Am-242, Am-242m, Am-243, Am-244, Am-244m, Cm-240, Cm-241, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246, Cm-247, Cm-248, Cm-249, Cm-250, Bk-247, Bk-249, Bk-250, Cf-249, Cf-250, Cf-251, Cf-252, Cf-254, Es-254, Es-255, Fm-255 Temperatures: 300 K. Origin: JENDL-3.3. Weighting spectrum: -- iwt=11 for NJOY-99. Legendre expansion: P6. Thermal scattering: free gas model. Self shielding: sigma-0, infinity, 10000, 1000, 300, 100, 30, 10, 1, 0.1, 1. E-5. Kerma factors are provided. NEA-1707/03: Corrections were made to the continuous inelastic scattering matrices (MT=91), for all nuclides for which this channel is open. This replaces the previous version. 2 - Methods: The nuclear data processing system NJOY-99.67 was used to produce MATXSLIBJ33. It can be further processed using TRANSX-2.15. 3 - Restrictions on the complexity of the problem: Accuracy of pointwise cross-section reconstruction: 0.1%; Upper limit of thermal region: 4.6 eV

  16. A study of the generation of 232U in UO2 and MOX fuels

    International Nuclear Information System (INIS)

    To clarify the generation pathway of 232U, an important nuclide for dose evaluation at various stages in the reuse of uranium, concentrations of 232U generated through various pathways were evaluated for UO2 and mixed oxide (MOX) fuels. Burnup calculation was conducted with ORIGEN2.2 code adopting ORLIBJ40 library, a set of cross-section libraries based on JENDL-4.0. It was found that differences in 232U concentrations in UO2 and MOX fuels mainly arise from differences in the initial compositions of 234U, 235U, and 236U. It was also found that the contribution of plutonium and americium isotopes in MOX fuels is small compared with that of uranium isotopes. The results clarified that the capture cross sections of 230Th, 231Pa, 235U, and 236U, as well as the (n,2n) cross sections of 237Np and 238U, have a large effect on the generation of 232U. Additional investigation showed that 232U concentration is strongly affected not only by time after irradiation but also by time before irradiation. (author)

  17. 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)

  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. 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.

  20. 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)

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

    International Nuclear Information System (INIS)

    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

  2. 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.

  3. 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.

  4. 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.

  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. Trace, ultratrace and isotope analysis of long-lived radionuclides by laser ablation inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has become established as a very efficient and sensitive technique for the analysis of solids. For the determination of long-lived radionuclides in solid nuclear waste or contaminated environmental samples LA-ICP-MS is the method of choice. The capability of LA-ICP-MS for measurements on long-lived radionuclides in non-conducting concrete matrix, which is a very common matrix in waste packages will be investigated. Of special interest are the limits of detection of long-lived radionuclides, which are compared for two different types of mass spectrometer coupled to a commercial laser ablation system. The limits of detection of long-lived radionuclides investigated in concrete matrix are determined in the low pg g-1 range in quadrupole LA-ICP-MS and in double-focusing sector field LA-ICP-MS. The main problem in the quantification of analytical results is that no suitable standard reference materials are available. Therefore synthetic laboratory standards (concrete matrix doped with long-lived radionuclides, such as 99Tc, 232Th, 233U, 235U, 237Np, 238U) were investigated by LA-ICP-MS. Different calibration procedures - the correction of analytical results with experimentally determined relative sensitivity coefficients (RSCs), the use of calibration curves and solution calibration by coupling LA-ICP-MS with an ultrasonic nebulizer - were applied for the determination of long-lived radionuclides, especially for Th and U in different solid samples. (orig.)

  7. ZZ FSXJ32, MCNP nuclear data library based on JENDL-3.2. ZZ FSXLIBJ33, MCNP nuclear data library based on JENDL-3.3

    International Nuclear Information System (INIS)

    -103, Rh-105, Pd-102, Pd-104, Pd-105, Pd-106, Pd-107, Pd-108, Pd-110, Ag-107, Ag-109, Ag-110m,Cd-106, Cd-108, Cd-110, Cd-111, Cd-112, Cd-113, Cd-114, Cd-116, In-113, In-115, Sn-112, Sn-114, Sn-115, Sn-116, Sn-117, Sn-118, Sn-119, Sn-120, Sn-122, Sn-123, Sn-124, Sn-126, Sb-121, Sb-123, Sb-124, Sb-125, Te-120, Te-122, Te-123, Te-124, Te-125, Te-126, Te-127m,Te-128, Te-129m,Te-130, I -127, I -129, I -131, Xe-124, Xe-126, Xe-128, Xe-129, Xe-130, Xe-131, Xe-132, Xe-133, Xe-134, Xe-135, Xe-136, Cs-133, Cs-134, Cs-135, Cs-136, Cs-137, Ba-130, Ba-132, Ba-134, Ba-135, Ba-136, Ba-137, Ba-138, Ba-140, La-138, La-139, Ce-140, Ce-141, Ce-142, Ce-144, Pr-141, Pr-143, Nd-142, Nd-143, Nd-144, Nd-145, Nd-146, Nd-147, Nd-148, Nd-150, Pm-147, Pm-148, Pm-148m,Pm-149, Sm-144, Sm-147, Sm-148, Sm-149, Sm-150, Sm-151, Sm-152, Sm-153, Sm-154, Eu-151, Eu-152, Eu-153, Eu-154, Eu-155, Eu-156, Gd-152, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, Tb-159, Er-162, Er-164, Er-166, Er-167, Er-168, Er-170, Hf-174, Hf-176, Hf-177, Hf-178, Hf-179, Hf-180, Ta-181, W-182, W-183, W-184, W-186, Hg-196, Hg-198, Hg-199, Hg-200, Hg-201, Hg-202, Hg-204, Pb-204, Pb-206, Pb-207, Pb-208, Bi-209, Ra-223, Ra-224, Ra-225, Ra-226, Ac-225, Ac-226, Ac-227, Th-227, Th-228, Th-229, Th-230, Th-232, Th-233, Th-234, Pa-231, Pa-232, Pa-233, U-232, U-233, U-234, U-235, U-236, U-237, U-238, Np-235, Np-236, Np-237, Np-238, Np-239, Pu-236, Pu-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Pu-244, Pu-246, Am-241, Am-242, Am-242m, Am-243, Am-244, Am-244m, Cm-240, Cm-241, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246, Cm-247, Cm-248, Cm-249, Cm-250, Bk-247, Bk-249, Bk-250, Cf-249, Cf-250, Cf-251, Cf-252, Cf-254, Es-254, Es-255, Fm-255 Temperatures: 300 K. Origin: JENDL-3.3. Thermal scattering: Free gas model Kerma factors are provided. The original JENDL-3.3 has two problems in Am-241 data. One is the missing of MF/MT=4/18, and the other is the incorrect neutron spectra for MT=18 below 500 keV. The updated data have been produced as JENDL-3

  8. U-Th-Ra-Pa Disequilibria in the Kasuga Seamounts: recent "sediment" flux melting in the Mariana rear arc

    Science.gov (United States)

    Gill, J.; Holden, P.

    2002-12-01

    Mariana volcanic front lavas define a U-Th isotope mixing line with an apparent age of 30 Ka between U-enriched "basalt fluid"-dominated Guguan and "sediment melt"-dominated Uracas in 238U-230Th equilibrium (Elliott et al., 1997). However, new results for basalts collected by dredging and diving on the shoshonitic Kasuga Seamounts, 10-20 km behind the VF, require re-interpretation of both Mariana components. Kasuga basalts are the local "sediment" extreme, reaching La/Sm = 5, Th/Nb=0.75, and eNd=3 in the most K-rich samples. Despite this extremity, their U-Th disequilibria lie along the same mixing line as for the VF, but extend to 20 percent 230Th-enrichment and (230Th)/(232Th) lower than at the intersection with the equiline. This indicates deeper melting than at the VF, and that the source's Th/U ratio was higher than the intersection. (226Ra)/(230Th) ratios extend to 3.5 even though samples have unknown eruption ages and Ba/Th is only 100, much lower than at the VF. (231Pa)/(235U) is mostly 1.7, higher than at the VF. (231Pa)/(230Th) correlates positively with excess U, consistent with recent flux melting. However, the mantle being melted is more fertile than at the VF, and the flux is more "sedimentary" apart from its disequilibria. Disequilibria in the highest-K Kasuga are most like Kick-em-Jenny, the most sediment-rich part of the Antilles.

  9. 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.

  10. 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

  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. 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.)

  13. In-beam spectroscopy of the Kπ = 0- bands in 230-236U

    International Nuclear Information System (INIS)

    The Kπ = 0- bands in even uranium nuclei were studied in the compound reactions 231Pa(p,2n)230U, 230,232Th(α,2n)232,234U and 236U(d,pn)236U. In-beam γ-rays were measured in coincidence with conversion-electrons, which were detected with an iron-free orange spectrometer. The negative-parity levels are observed up to intermediate spins (I-). In addition, the 1- and 3- levels in 230U were confirmed by a decay study with an isotope separated 230Pa source. For the heavier isotopes (A > or approx. 232) the properties of the Kπ = 0- bands (energies and γ-branchings) are consistent with a vibrational character of these bands. For 230U the Kπ = 0- band lies at rather low energy (E(1-) = 367 keV), and the level spacings within this band are very similar to those of the isotones 228Th and 226Ra, which might indicate the onset of a stable octupole deformation. (orig.)

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

    International Nuclear Information System (INIS)

    U-series dating is based on the decay of the two long-lived isotopes238U(τ1/2=4.47 x 109 years) and 235U (τ1/2 0.7 x 109 years). 238U and its intermediate daughter isotopes 234U (τ1/2 = 245.4 ka) and 230Th (τ1/2 = 75.4 ka) have been the main focus of recently developed mass spectrometric techniques (Edwards et al., 1987) while the other less frequently used decay chain is based on the decay 235U to 231Pa (τ1/2 = 32.8 ka). Both the 238U and 235U decay chains terminate at the stable isotopes 206Pb and 207Pb respectively. Thermal ionization mass spectrometry (TIMS) has a number of inherent advantages, mainly the ability to measure isotopic ratios at high precision on relatively small samples. In spite of these now obvious advantages, it is only since the mid-1980's when Chen et al., (1986) made the first precise measurements of 234U and 232Th in seawater followed by Edwards et al., (1987) who made combined 234U-230Th measurements, was the full potential of mass spectrometric methods first realised. Several examples are given to illustrate various aspects of TIMS U-series

  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. 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.

  17. Production of photofission fragments and study of their nuclear structure

    International Nuclear Information System (INIS)

    The fission fragments of heavy nuclei (Z > 90) are neutron-rich isotopes of the elements from Zn (Z = 30) to Nd (Z = 60) with a neutron number of 45 - 90. The large neutron excess in the fission fragments under study could lead to the essential change in their structure and radioactive decay characteristics. This change will manifest itself in the appearance of new magic numbers of protons or neutrons, new regions of deformation, of new islands of isomerism. The high energy of β-decay can result in the new, much rarer, modes of radioactive decay (for example, β2n or βα). Study of the nuclear structure of fission fragments is one of the main directions of the DRIBs project, being developed in the Flerov Laboratory of Nuclear Reactions, JINR. The aim of this project is the production of the intense beams of accelerated radioactive nuclei in a wide range of Z and A and the study of their properties. The neutron-rich nuclei of medium mass numbers will be produced in the photofission reactions on the electron accelerator microtron MT-25. The parameters of this microtron allow to produce the high yield of photofission fragments (up to 1011s-1 at the irradiation of thick uranium target by Bremsstrahlung. The first experiments using photofission fragments were performed. The independent yields of Kr (A = 87 - 93) and Xe (A = 137 - 143) fragments at the photofission of different heavy nuclei 232 Th, 238 U, 237 Np, 244 Pu were measured. These data allows to refer about yields of the most neutron-rich isotopes. The rare mode decay, emission of delayed neutron pair (β2n), was observed at the photofission of 238 U. It is, probably, 136 Sb, the intensity of β 2n branch is about 10-3. Other experiments using neutron, gamma and laser spectroscopy methods are planned. (authors)

  18. 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.

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

    International Nuclear Information System (INIS)

    A high sensitivity analytical method for 237Np analysis was developed and applied to groundwater samples from the Nevada National Security Site (NNSS) using short-lived 239Np as a yield tracer and HR magnetic sector ICP-MS. The 237Np concentrations in the vicinity of the Almendro, Cambric, Dalhart, Cheshire, and Chancellor underground nuclear test locations range from <4 × 10−4 to 2.6 mBq/L (6 × 10−17–4.2 × 10−13 mol/L). All measured 237Np concentrations are well below the drinking water maximum contaminant level for alpha emitters identified by the U.S. EPA (560 mBq/L). Nevertheless, 237Np remains an important indicator for radionuclide transport rates at the NNSS. Retardation factor ratios were used to compare the mobility of 237Np to that of other radionuclides. The results suggest that 237Np is less mobile than tritium and other non-sorbing radionuclides (14C, 36Cl, 99Tc and 129I) as expected. Surprisingly, 237Np and plutonium (239,240Pu) 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, 237Np is migrating downgradient from NNSS underground nuclear tests at very low but measureable concentrations. - Highlights: • A high sensitivity analytical method for 237Np analysis in groundwater was developed. • Groundwater samples from the Nevada National Security Site (NNSS) were analyzed. • 237Np concentrations were well below the EPA maximum contaminant level in drinking water. • 237Np is less mobile than 3H and other non-sorbing radionuclides. • 237Np and Pu apparent retardation factors are similar

  20. 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...

  1. 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...... varied between 1.98 ± 0.05 and 14.1 ± 0.3 mBq/m2. The contribution from the Chernobyl accident to the total 237Np deposition in peat was 0.1–13%, the Chernobyl-derived fraction of total 237Np in peat being much lower than the previously determined corresponding Chernobyl-derived fractions of 239+240Pu...

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

    International Nuclear Information System (INIS)

    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, 3H, 14C, 60Co, 79Se, 90Sr, 99Tc as pertechnetate, 106Ru/Rh, 125Sb, 134Cs, 137Cs, 152Eu, 154Eu, 155Eu, 238Pu, 239+240Pu, 241Am, 242Cm, and 243+244Cm; (3) Inductively-coupled plasma mass spectrometry for 237Np, 239Pu, 240Pu, 99Tc, 126Sn, 129I, 231Pa, 233U, 234U, 235U, 236U, 238U, 241AMU, 242AMU, 243AMU, 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, NO2, NO3, PO4, SO4, 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 contract limits (molar ratio of analyte to sodium or ratio of becquerels of analyte to moles of sodium) defined in Specification 7 for Envelope A. Except for a few cases, the characterization results met or surpassed the

  3. 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

  4. Field experiment determinations of distribution coefficients of actinide elements in alkaline lake environments

    International Nuclear Information System (INIS)

    Measurements of the radioisotope concentrations of a number of elements (Am, Pu, U, Pa, Th, Ac, Ra, Po, Pb, Cs, and Sr) in the water and sediments of a group of alkaline (pH = 9-10), saline lakes demonstrate greatly enhanced soluble-phase concentrations of elements with oxidation states of (III)-(VI) as the result of complexing by carbonate ion. Ratios of soluble radionuclide concentrations in Mono Lake to those in seawater ([CO32-] in Mono Lake = 200 times that of seawater) were: Pu(approx. =10), 238U(approx. =150), 231Pa, 228Th, 230Th(approx. =103), and 232Th(approx. =105). Effective distribution coefficients of these radionuclides in high CO32- environments are several orders of magnitude lower (i.e., less particle reactive) than in most other natural waters. The importance of CO32- ion on effective K/sub d/ values was also strongly suggested by laboratory experiments in which most of the dissolved actinide elements became adsorbed to particles after a water sample normally at a pH of 10 was acidified, stripped of all CO2, and then returned to pH 10 by adding NH4OH. Furthermore, the effect of complexation by organic ligands is of secondary importance in the presence of appreciable carbonate ion concentration. Neither pure phase solubility calculations nor laboratory scale K/sub d/ determinations accurately predicted the measured natural system concentrations. Therefore, measurements of the distribution of radionuclides in natural systems are essential for assessment of the likely fate of potential releases from high level waste repositories to groundwater. 50 references, 31 figures, 43 tables

  5. 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.

  6. 10 CFR Appendix L to Part 110 - Illustrative List of Byproduct Materials Under NRC Export/Import Licensing Authority a

    Science.gov (United States)

    2010-01-01

    ...) Antimony 126 (Sb 126) Arsenic 73 (As 73) Arsenic 74 (As 74) Arsenic 76 (As 76) Arsenic 77 (As 77) Barium... 149 (Nd 149) Neptunium 235 (Np 235) Neptunium 237 (Np 237) Nickel 59 (Ni 59) Nickel 63 (Ni 63)...

  7. 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

  8. 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

  9. 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

  10. 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

  11. /sup 238/Pu processing at the Savannah River Plant

    Energy Technology Data Exchange (ETDEWEB)

    Burney, G.A.

    1983-01-01

    /sup 238/Pu is produced by irradiating /sup 237/Np. The /sup 237/Np is produced as a byproduct when natural or enriched uranium is irradiated with neutrons. The /sup 237/Np is separated by solvent extraction and ion exchange. It is converted to NpO/sub 2/ and fabricated into targets for irradiation. The irradiated targets are cooled and dissolved in strong nitric acid. The /sup 238/Pu and /sup 237/Np are separated from fission products and other cationic impurities and from each other by three cycles of anion exchange. The /sup 237/Np is recycled to produce more targets for irradiation. The pure /sup 238/Pu solution is precipitated as Pu oxalate and calcined to PuO/sub 2/. After several powder-conditioning steps, the PuO/sub 2/ is hot pressed into fuel forms. Each form is encased in iridium for loading into a specially designed power unit for space application. 8 references, 9 figures, 1 table.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Impact of fission product partitioning and transmutation of Np-237, I-127 and Tc-99 on waste disposal strategies

    Energy Technology Data Exchange (ETDEWEB)

    Beatsle, L.H. [Studiecentrum voor Kernenergie - Centre d' Etude de l' Energie Nucleaire (SCK-CEN), Mol (Belgium)

    1991-07-01

    From the point of view of waste management, three isotopes {sup 237}Np, {sup 129}I and {sup 99}Tc deserve particular attention since they cannot be confined within any presently known geological barrier. The safety assessment studies showed that {sup 129}I diffuses through 50 m of clay after 5000 years and creates a radiological burden which is superior to the other nuclides. {sup 99}Tc and {sup 237}Np emerge much later (million years) but cannot be confined in the repository. Separation of {sup 237}Np is already envisaged by the reprocessing plants and small modifications to the PUREX process permit to separate this nuclide quantitatively. However, the overall Np reduction factor cannot be higher than 3 to 4 because {sup 237}Np is formed by alpha-decay of {sup 241}Am which is immobilized in the glass. The irradiation technology to transmute {sup 237}Np into {sup 238}Pu is available. Iodine is separated from the dissolver off-gases in the reference fuel cycle and could be transformed into a stable Ba(IO{sub 3}){sub 2} matrix which can serve as irradiation 1291 matrix to destroy. Technetium is produced as insoluble residue and occurs in the waste streams together with Ru, Rh and Pd. Its recovery is still questionable and needs further developments. Irradiation of small targets in HFRs can lead to a 90% transmutation of these long-lived isotopes but the irradiation periods (particularly for {sup 129}I) are very long. The present HFR generation is not designed to handle large amounts of long-lived radionuclides and new more powerful units ought to be designed for that purpose. (author)

  18. 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.

  19. 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.

  20. Studies of natural radioactivity of some Egyptian rock phosphates

    International Nuclear Information System (INIS)

    226Ra, 235U, 232Th and 40K activity concentrations (Bq/kg) in some Egyptian phosphate samples have been measured using HPGe gamma spectrometer. Also their radium equivalent activities were calculated and discussed. (author)

  1. ZZ KASHIL-E70, 199 N, 42 Photon Groups Cross Sections in MATXS Format Based on ENDF/B-VII.0 for Shielding Applications

    International Nuclear Information System (INIS)

    1 - Description: Format: MATXS, 204 nuclides processed with NJOY99.245. Number of groups: 199 neutron-, 42 photon-groups. 204 Nuclides including 8 thermal scattering law data: H-1, H-2, H-3, He-3, He-4, Li-6, Li-7, Be-9, Be-9, Be-9, B-10, B-11, C-nat, C-nat, N-14, N-15, O-16, O-17, F-19, Na-23, Mg-24, Mg-25, Mg-26, Al-27, Si-28, Si-29, Si-30, P-31, S-32, S-33, S-34, S-36, Cl-35, Cl-37, K-39, K-40, K-41, Ca-40, Ca-42, Ca-43, Ca-44, Ca-46, Ca-48, Sc-45, Ti-46, Ti-47, Ti-48, Ti-49, Ti-50, V-nat, Cr-50, Cr-52, Cr-53, Cr-54, Mn-55, Fe-54, Fe-56, Fe-57, Fe-58, Co-59, Ni-58, Ni-60, Ni-61, Ni-62, Ni-64, Cu-63, Cu-65, Ga-69, Ga-71, Y-89, Zr-90, Zr-91, Zr-92, Zr-94, Zr-96, Nb-93, Mo-92, Mo-94, Mo-95, Mo-96, Mo-97, Mo-98, Mo-100, Pd-102, Pd-104, Pd-105, Pd-106, Pd-108, Pd-110, Ag-107, Ag-109, Cd-106, Cd-108, Cd-110, Cd-112, Cd-113, Cd-114, Cd-116, In-113, In-115, I-127, Xe-124, Xe-126, Xe-128, Xe-129, Xe-130, Xe-131, Xe-132, Xe-134, Xe-136, Cs-133, Ba-138, Pr-141, Nd-143, Nd-145, Nd-146, Nd-148, Nd-150, Pm-147, Sm-147, Sm-151, Sm-152, Eu-151, Eu-152, Eu-153, Eu-154, Eu-155, Gd-152, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, Dy-164, Ho-165, Lu-175, Lu-176, Hf-174, Hf-176, Hf-177, Hf-178, Hf-179, Hf-180, Ta-181, Ta-182, W-182, W-183, W-184, W-186, Re-185, Re-187, Ir-191, Ir-193, Au-197, Pb-206, Pb-207, Pb-208, Bi-209, Th-230, Th-232, Pa-231, Pa-233, U-232, U-233, U-234, U-235, U-236, U-237, U-238, Np-237, Np-238, Np-239, Pu-236, Pu-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Pu-243, Pu-244, Am-241, Am-242, Am-242m, Am-243, Cm-241, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246, Cm-247, Cm-248, Bk-249, Cf-249, Cf-250, Cf-251, Cf-252, Cf-253, Es-253. Origin: ENDF/B-VII.0. Weighting spectrum: 300, 600, 1000, 2100 K. The KASHIL-E70 is a MATXS-format, 199-group neutron and 42-group photon cross section library for shielding applications based on ENDF/B-VII.0. The library contains 204 nuclide data including 8 thermal scattering law data processed by the NJOY99.259 code patched with NEA

  2. U/Th-dating living and young fossil corals from the central tropical Pacific

    Science.gov (United States)

    Cobb, Kim M.; Charles, Christopher D.; Cheng, Hai; Kastner, Miriam; Edwards, R. Lawrence

    2003-05-01

    This study evaluates the accuracy of U/Th dates for young (reef corals, both living and fossil, and explores strategies for refining those dates. The high precision of the U/Th method (±1-2%) for dating young corals is well-established. Earlier studies have demonstrated the method's accuracy for select samples of known age. However, these studies have focused on typical samples that have extremely low 232Th concentrations (tens of pg/g). Here we study the dating systematics of young corals that have low but significant amounts of 232Th (up to 1000 pg/g), indicating the presence of small fractions of non-radiogenic 230Th (i.e. 230Th not generated by in situ U decay). We report U/Th ages for living and subaerially exposed fossil corals from Palmyra Island, located in the central tropical Pacific, that range from 50 to 700 yr old. The Palmyra corals contain varying amounts of 232Th and small fractions of associated non-radiogenic 230Th. Uncertainty associated with the correction for non-radiogenic 230Th can lead to significant errors in U/Th dates. We have characterized non-radiogenic 230Th/ 232Th values, ( 230Th/ 232Th) nr, as a means of minimizing this source of error. We calculate ( 230Th/ 232Th) nr values ranging from 0 to 2×10 -5 for the Palmyra living corals by comparing measured U/Th dates to absolute dates for the living coral, whose chronology is well-established. For the fossil corals, we employ three different approaches to arrive at ( 230Th/ 232Th) nr estimates. First, we compare measured U/Th dates to absolute dates in samples from a young fossil coral that overlaps the living coral. Next, we use the firm relative dating constraints imposed by five overlapping fossil corals from the 14th-15th centuries to calculate ( 230Th/ 232Th) nr values. Finally, we attempt to anchor the 14th-15th century floating coral chronology to an absolute chronology by correlating the climate signals in the coral records to those in absolutely dated climate proxy records. All

  3. Natural Radioactivity in Tanzania Cements and their Raw Materials

    OpenAIRE

    Aloyce Isaya Amasi; Kelvin Mark Mtei; Ijumba Jasper Nathan; Pawel Jodłowski; Chau Nguyen Dinh

    2014-01-01

    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 materia...

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

    OpenAIRE

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

    2015-01-01

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

  5. Neutron scattering studies in the actinide region

    International Nuclear Information System (INIS)

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

  6. Optimization of small long-life PWR based on thorium fuel

    Energy Technology Data Exchange (ETDEWEB)

    Subkhi, Moh Nurul, E-mail: nsubkhi@students.itb.ac.id [Nuclear Physics and Biophysics Research Group, Faculty of Mathematics and Natural Science, Bandung Institute of Technology. Jalan Ganesha 10, Bandung (Indonesia); Physics Dept., Faculty of Science and Technology, State Islamic University of Sunan Gunung Djati Bandung Jalan A.H Nasution 105 Bandung (Indonesia); Suud, Zaki, E-mail: szaki@fi.itb.ac.id; Waris, Abdul; Permana, Sidik [Nuclear Physics and Biophysics Research Group, Faculty of Mathematics and Natural Science, Bandung Institute of Technology. Jalan Ganesha 10, Bandung (Indonesia)

    2015-09-30

    A conceptual design of small long-life Pressurized Water Reactor (PWR) using thorium fuel has been investigated in neutronic aspect. The cell-burn up calculations were performed by PIJ SRAC code using nuclear data library based on JENDL 3.2, while the multi-energy-group diffusion calculations were optimized in three-dimension X-Y-Z geometry of core by COREBN. The excess reactivity of thorium nitride with ZIRLO cladding is considered during 5 years of burnup without refueling. Optimization of 350 MWe long life PWR based on 5% {sup 233}U & 2.8% {sup 231}Pa, 6% {sup 233}U & 2.8% {sup 231}Pa and 7% {sup 233}U & 6% {sup 231}Pa give low excess reactivity.

  7. 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.

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

    International Nuclear Information System (INIS)

    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

  9. Refinement of Pu parent-daughter isotopic and concentration analysis for forensic (dating) purposes

    International Nuclear Information System (INIS)

    Plutonium (Pu) metal samples from an interlaboratory exchange exercise and simulated swipe samples were dated using plutonium-uranium (Pu-U) and plutonium-americium (Pu-Am). Metal data were evaluated for consistency and the swipe data against its source material. Metal ages based on 239Pu versus 235U and 240Pu versus 236U agreed to within a few percent, while the 238Pu-234U and 241Pu-241Am measurements had larger uncertainties. Swipe ages compared favorably with the material's known history. Neptunium (237Np) analyses were examined in the context of the 241Pu-241Am-237Np system to estimate whether Np can provide insights on material from which Am, Np, and U were removed. (author)

  10. A chromatographic separation of neptunium and protactinium using 1-octanol impregnated onto a solid phase support

    International Nuclear Information System (INIS)

    We have developed a new chromatographic method to efficiently separate and isolate neptunium (Np) and protactinium (Pa), based on the selective extraction of protactinium by primary alcohols. The effectiveness of the new technology is demonstrated by efficient separation of 233Pa from parent radionuclide 237Np, using a hydrochloric acid mobile-phase medium. Our new approach reproducibly isolated 233Pa tracer with a yield of 99 ± 1 % (n = 3; radiochemical purity 100 %) and enabled chemical recovery of 237Np parent material of 92 ± 3 % (radiochemical [99 %) for future 233Pa tracer preparations. Compared to previous methods, the new approach reduces radioactive inorganic and organic waste; simplifies the separation process by eliminating cumbersome liquid-liquid extractions; and allows isolation of radiochemically-pure fractions in less than 1 h. (author)

  11. Neptunium distribution in PUREX process streams

    International Nuclear Information System (INIS)

    237Np is one of the most important minor actinides present in spent fuel both from environmental and application point of view. The routing of neptunium to the particular waste stream of PUREX process is required for its separation and purification as 237Np is the target nuclide for production of 238Pu. In addition, the routing of neptunium to a particular PUREX stream will help in better waste management, which in turn will reduce its bearing on the environment considering its long half life, alpha emitting properties and mobile nature. In order to route Neptunium to a particular waste stream of PUREX process, it is imperative to understand the distribution of neptunium in various process streams. Although, there are reports on Np distribution under simulated conditions of PUREX streams, the present study deals with neptunium determination in actual PUREX streams samples. (author)

  12. 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)

  13. 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)

  14. Nordic collaboration on the use of mass-spectrometers for the analysis of radioisotopes. NKS-project NORCMASS. Final report

    International Nuclear Information System (INIS)

    This report cover an overview of the work performed during a three year (2003-2005) project initialized with the purpose of identifying and work on problems in isotope ratio and ultra trace measurements of primarily plutonium and uranium isotopes and 237Np using ICPMS. The project also included an educational part aiming to describe fundamental aspects and practical steps for radioisotope measurements using ICP-MS. (au)

  15. Electron paramagnetic resonance and electron nuclear double resonance of 237-neptunium hexafluoride in uranium hexafluoride single crystals

    Science.gov (United States)

    Butler, James E.; Hutchison, Clyde A., Jr.

    1981-03-01

    The EPR and ENDOR spectra of 237NpF6 molecules dilutely substituted for host molecules in single crystals of UF6 at temperatures between 1.2 and 2.1 °K have been obtained at microwave frequencies, ˜9.4 and ˜9.7 GHz. Approximate values are given for the parameters in a spin Hamiltonian formalism that describes the measurements. The results are discussed.

  16. 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

  17. 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.

  18. 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.

  19. Modelling of reaction cross sections and prompt neutron emission

    OpenAIRE

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

    2010-01-01

    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.

  20. 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.)

  1. 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)

  2. High-sensitivity fast neutron detector KNK-2-7M

    International Nuclear Information System (INIS)

    The construction of the fast neutron detector KNK-2-7M is briefly described. The results of the study of the detector in the pulse-counting mode are given for the fissions of 237Np nuclei in the radiator of the neutron-sensitive section and in the current mode with the separation of sectional currents of functional sections. The possibilities of determining the effective number of 237Np nuclei in the radiator of the neutronsensitive section are considered. The diagnostic possibilities of the detector in the counting mode are shown by example of the analysis of the reference data from the neutron-field characteristics in the working hall of the BR-K1 reactor. The diagnostic possibilities of the detector in the current operating mode are shown by example of the results of measuring the 237Np-fission intensity in the BR-K1 reactor power start-ups implemented in the mode of fission-pulse generation on delayed neutrons at the detector arrangement inside the reactor core cavity under conditions of a wide variation of the reactor radiation field

  3. 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.

  4. Radiochemical determination of Np-237 in soil samples contaminated with weapon grade plutonium

    International Nuclear Information System (INIS)

    The Palomares terrestrial ecosystem (Andalusia, southwestern Spain) is known to constitute a natural laboratory to study the distribution, behaviour and migration of certain actinides, such as plutonium, americium and neptunium. This scenario is partially contaminated with weapon grade plutonium since the burn-out and fragmentation of two of the four thermonuclear bombs accidentally dropped by a B-52 from the USA Air Force back in 1966. While performing radiometric measurements on the field, with the goal of gathering information about the surface contamination levels, the possible presence of 237Np was observed through its 29 keV gamma emission. To accomplish a more detailed characterization of the source term in the contaminated area using the isotopic ratios Pu-Am-Np, the radiochemical isolation and later quantification by alpha spectrometry of 237Np was initiated. As a first approach, a bibliographic study was undertaken, considering different radiochemical methods applied to a variety of samples such as soils, sediments, sea water, lichens, etc. The radiochemical procedure selected in our laboratory involves separation of neptunium from americium, uranium and plutonium with ionic resin (AG 1x2), given that in soil samples from Palomares 239+240Pu levels are several orders of magnitude higher than 237Np. Then neptunium is isolated using TEVA organic resin. After electro-deposition, quantification is performed by high resolution alpha spectrometry. Different analyses have been performed with blank solutions spiked with 236Pu, 237Np and 244Cm, solutions resulting from the total dissolution of isolated radioactive particles and soil samples. The lack of an appropriate tracer in our lab led to the determination of an average percentage of Np recovery using a certified solution of 237Np. Decontamination percentages obtained during the Pu-Np separation ranged from 98 % to 100 %. Some tests to investigate the effect of the addition or absence of NaNO2 (responsible for

  5. Partial neutron capture cross sections of actinides using cold neutron prompt gamma activation analysis

    International Nuclear Information System (INIS)

    Nuclear waste needs to be characterized for its safe handling and storage. In particular long-lived actinides render the waste characterization challenging. The results described in this thesis demonstrate that Prompt Gamma Neutron Activation Analysis (PGAA) with cold neutrons is a reliable tool for the non-destructive analysis of actinides. Nuclear data required for an accurate identification and quantification of actinides was acquired. Therefore, a sample design suitable for accurate and precise measurements of prompt γ-ray energies and partial cross sections of long-lived actinides at existing PGAA facilities was presented. Using the developed sample design the fundamental prompt γ-ray data on 237Np, 241Am and 242Pu were measured. The data were validated by repetitive analysis of different samples at two individual irradiation and counting facilities - the BRR in Budapest and the FRM II in Garching near Munich. Employing cold neutrons, resonance neutron capture by low energetic resonances was avoided during the experiments. This is an improvement over older neutron activation based works at thermal reactor neutron energies. 152 prompt γ-rays of 237Np were identified, as well as 19 of 241Am, and 127 prompt γ-rays of 242Pu. In all cases, both high and lower energetic prompt γ-rays were identified. The most intense line of 237Np was observed at an energy of Eγ=182.82(10) keV associated with a partial capture cross section of σγ=22.06(39) b. The most intense prompt γ-ray lines of 241Am and of 242Pu were observed at Eγ=154.72(7) keV with σγ=72.80(252) b and Eγ=287.69(8) keV with σγ=7.07(12) b, respectively. The measurements described in this thesis provide the first reported quantifications on partial radiative capture cross sections for 237Np, 241Am and 242Pu measured simultaneously over the large energy range from 45 keV to 12 MeV. Detailed uncertainty assessments were performed and the validity of the given uncertainties was demonstrated. Compared

  6. 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.

  7. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2015-11-01

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

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

    International Nuclear Information System (INIS)

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

  12. 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.

  13. 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)

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

    Directory of Open Access Journals (Sweden)

    Quesada José Manuel

    2016-01-01

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

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

    International Nuclear Information System (INIS)

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

  16. 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.

  17. 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...

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

    International Nuclear Information System (INIS)

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

  19. 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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2010-11-01

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

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

    International Nuclear Information System (INIS)

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

  3. 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.

  4. Measuring radioactivity level in various types of rice using NaI (Tl) detector

    OpenAIRE

    Laith A. Najam; Nada F. Tawfiq; Fouzey H. Kitha

    2015-01-01

    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 na...

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

    International Nuclear Information System (INIS)

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

  6. 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)

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

    OpenAIRE

    BALDIK, Hüseyin AYTEKIN and Rıdvan

    2008-01-01

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

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

    OpenAIRE

    B., CENGİZ G.; REŞİTOĞLU,; De, S.

    2014-01-01

    The objective of this study is to determine the distribution of natural radionuclides in surface soils in the Karscity center, Turkey. The activity concentrations of 238U, 232 Th, 40 K and 137Cs in 38 soil samples collected from the study area were measured through NaI(Tl) gamma spectrometry. The average activities of the samples were determined to be 47.8, 31.2 and 536 Bqkg-1 for the natural radionuclides 226Ra (238U), 232Th, 40K, respectively, and 18 Bqkg-1 for the fission product 137Cs. ...

  9. Radiological impact assessment for near surface disposal of thorium waste

    International Nuclear Information System (INIS)

    Thorium (232Th) itself is not fissile and so is not directly usable in a thermal neutron reactor. However, it is fertile and upon absorbing a neutron will transmute to uranium-233 (233U), which is a fissile fuel material. The thorium fuel fabrication may lead to low level waste comprising of 232Th. This waste may be disposed of in the Near Surface Disposal Facility (NSDF). The very low probability event of leaching of the waste may lead to contamination of the groundwater system. This paper deals with the estimation of the radiological impact of thorium waste disposal in NSDF through groundwater drinking pathway using the Multiple Area Source Model (MASOM). (author)

  10. Variations in radioactivity of phosphate rocks from different sites in central eastern desert of upper Egypt

    International Nuclear Information System (INIS)

    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 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 data obtained by others

  11. Gamma spectroscopic analysis of powdered granite samples in some Eastern desert's areas

    International Nuclear Information System (INIS)

    A gamma spectroscopic method for the determination of 226Ra, 232Th and 40K contents in powdered granite samples from areas in different sites in Eastern desert is presented. HPGe detector setup, coaxial type and 8192 channels MCA were applied for measurements. The data show that the concentration values of 226Ra, 232Th and 40K in these samples ranged between 102-640, 56-161 and 774-1234 (Bq/kg), respectively. Radium equivalent activty (Raeq) and activity level in all samples were calculated. The data are discussed and compared with other experimental values

  12. 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.

  13. 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.

  14. Natural environmental radioactivity and the corresponding health risk in Johor Bahru District, Johor, Malaysia

    International Nuclear Information System (INIS)

    This study aims to obtain the baseline data on environmental terrestrial radiation and to assess the corresponding health risk in Johor Bahru District, Johor, Malaysia. The mean activity concentrations of 232Th, 226Ra and 40K were 119 ± 6, 51 ± 4 and 158 ± 21 Bq kg-1, respectively. Primordial radionuclide 232Th is the main contributor to gamma dose rate and the mean found to be 135 nGy h-1. Gross alpha and gross beta activity concentrations in water were 0.012 ± 0.003 and 0.234 ± 0.018 Bq L-1, respectively. (author)

  15. 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.

  16. Radionuclide Transport in Fracture-Granite Interface Zones

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Q; Mori, A

    2007-09-12

    In situ radionuclide migration experiments, followed by excavation and sample characterization, were conducted in a water-conducting shear zone at the Grimsel Test Site (GTS) in Switzerland to study diffusion paths of radionuclides in fractured granite. In this work, we employed a micro-scale mapping technique that interfaces laser ablation sampling with inductively coupled plasma-mass spectrometry (LA/ICP-MS) to measure the fine-scale (micron-range) distribution of actinides ({sup 234}U, {sup 235}U, and {sup 237}Np) in the fracture-granite interface zones. Long-lived {sup 234}U, {sup 235}U, and {sup 237}Np were detected in flow channels, as well as in the adjacent rock matrix, using the sensitive, feature-based mapping of the LA/ICP-MS technique. The injected sorbing actinides are mainly located within the advective flowing fractures and the immediately adjacent regions. The water-conducting fracture studied in this work is bounded on one side by mylonite and the other by granitic matrix regions. These actinides did not penetrate into the mylonite side as much as the relatively higher-porosity granite matrix, most likely due to the low porosity, hydraulic conductivity, and diffusivity of the fracture wall (a thickness of about 0.4 mm separates the mylonite region from the fracture) and the mylonite region itself. Overall, the maximum penetration depth detected with this technique for the more diffusive {sup 237}Np over the field experimental time scale of about 60 days was about 10 mm in the granitic matrix, illustrating the importance of matrix diffusion in retarding radionuclide transport from the advective fractures. Laboratory tests and numerical modeling of radionuclide diffusion into granitic matrix was conducted to complement and help interpret the field results. Measured apparent diffusivity of multiple tracers in granite provided consistent predictions for radionuclide transport in the fractured granitic rock.

  17. Challenge in determination of long-lived radionuclides by ICP-MS

    International Nuclear Information System (INIS)

    The ultra-trace and isotope analysis of long-lived radionuclides in environmental materials (in biological or geological samples and waters) is relevant of increasing importance [1-5].E.g., the determination of long-lived radionuclides is for the detection of radionuclide contamination in environmental materials in which several radioactive nuclides (e.g.99Tc, 129I , 237Np, 239Pu, 240Pu, 241Am) are present from fallout due to nuclear weapons testing, nuclear power plants or nuclear accidents. Especially, isotope ratios of uranium and plutonium [6] can indicate the origin of contamination in the environmental samples

  18. 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...... 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...

  19. Effects of the shape of tracer source on 90Sr migration

    International Nuclear Information System (INIS)

    The method and the results of the tracer migration test in horizontal column, which was conducted in the experimental shaft of the CIRP's Field Test Site, are introduced. The effects of the shape of tracer source on 90Sr migration are discussed. The results indicates that adsorption capacity of loess to 90Sr, 237Np, 238Pu and 241Am are relatively strong. Humus retarded migration of 90Sr. Retardation coefficient of 90Sr, under the condition of plane source, is less than that under the condition of point source. (authors)

  20. INERT-MATRIX FUEL: ACTINIDE ''BURNING'' AND DIRECT DISPOSAL

    International Nuclear Information System (INIS)

    Excess actinides result from the dismantlement of nuclear weapons (Pu) and the reprocessing of commercial spent nuclear fuel (mainly 241 Am, 244 Cm and 237 Np). In Europe, Canada and Japan studies have determined much improved efficiencies for burnup of actinides using inert-matrix fuels. This innovative approach also considers the properties of the inert-matrix fuel as a nuclear waste form for direct disposal after one-cycle of burn-up. Direct disposal can considerably reduce cost, processing requirements, and radiation exposure to workers

  1. 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.

  2. Progress on Radiochemical Analysis for Nuclear Waste Management in Decommissioning

    DEFF Research Database (Denmark)

    Hou, Xiaolin; Qiao, Jixin; Shi, Keliang;

    With the increaed numbers of nuclear facilities have been closed and are being or are going to be decommissioned, it is required to characterise the produced nuclear waste for its treatment by identification of the radionuclides and qualitatively determine them. Of the radionuclides related...... for determination of long-lived 94Nb in the nuclear waste; (2) development of a sensitive method for measurement of 237Np using AMS; (3) improvement of analytical method for determinaiton of 99Tc using ICP-MS; (4) improvement of method for 14C measurement using LSC; and (5) Characterization of steel samples from...

  3. Alpha self-irradiation effects in ternary oxides of actinides elements: The zircon-like phases AmIIIVO4 and AIINpIV(VO4)2 (A=Sr, Pb)

    International Nuclear Information System (INIS)

    We report the experimental studies of irradiation damage from alpha decay in neptunium and americium vanadates versus cumulative dose. The isotopes used were the transuranium α-emitter 237Np and the α,γ-emitter 241Am. Neptunium and americium vanadates self-irradiation was studied by X-ray diffraction method (XRD). The comparison of the powder diffraction patterns reveal that the irradiation has no apparent effect on the neptunium phases while the americium vanadate swells and becomes metamict as a function of cumulative dose

  4. A novel assay method for the trace determination of Th and U in copper and lead using inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    LaFerriere, B.D.; Maiti, T.C.; Arnquist, I.J.; Hoppe, E.W., E-mail: eric.hoppe@pnnl.gov

    2015-03-01

    This study describes a novel sample preparation and assay method developed, primarily in support of the MAJORANA DEMONSTRATOR neutrinoless double-beta decay experiment, for the determination of extremely low levels of Th and U in copper and lead shielding components. Meticulously clean sample preparation methods combined with anion exchange separations for analyte pre-concentration and matrix removal were developed. Quantification was performed by isotope dilution inductively coupled plasma mass spectrometry. Detection limits of 0.0084 pg {sup 232}Th/g (0.034 µBq {sup 232}Th/kg) and 0.0106 pg {sup 238}U/g (0.131 µBq {sup 238}U/kg) were determined for copper, while detection limits of 0.23 pg {sup 232}Th/g (0.94 µBq {sup 232}Th/kg) and 0.46 pg {sup 238}U/g (5.7 µBq {sup 238}U/kg) were achieved for lead. These methods allow the Majorana Collaboration to accurately assay detector components and ensure that the experiment's stringent radiopurity requirements are met.

  5. 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.

  6. Measurement of Natural Radioactivity in Soil Along the Bank of River Kaduna – Nigeria.

    Directory of Open Access Journals (Sweden)

    Abdullahi, M. A

    2013-09-01

    Full Text Available Gamma-ray spectrometry of natural radioactivity was carried out in soil along the bank of river Kaduna Nigeria using EDXRF techniques. The activity concentration in Bq/kg for 40K and 232Th were calculated from the % weight of K and Th determined in the soil samples. The mean activity concentration of 40K was found to be 1168.13 ±94.67Bq/kg in range between 810.62 ± 21.91 to 1765.32 ± 31.30 Bq/kg. The mean activity concentration of 232Th was found to be 18.76 ± 2.51Bq/kg in range between 8.12 ± 2.44 to 33.70 ± 6.90 Bq/kg. The highest values of 40K and 232Th were found in samples obtained from GRA 2 and this can be attributed to the increase anthropogenic activities going on in the area. The mean activity concentration of 40K in the study area is higher than world average value while that of 232Th is lower than world average value

  7. Polarization phenomena in heavy ion induced reactions

    International Nuclear Information System (INIS)

    Mechanisms of heavy ion reactions are discussed from the experimental results on polarization of products 12B in 14N + 100Mo and 14N + 232Th reactions. Polarization determines the signs of deflection functions corresponding to large energy losses. (author)

  8. Decision making algorithm of the rehabilitation of agricultural lands contaminated with heavy natural radionuclides

    International Nuclear Information System (INIS)

    Problem of rehabilitation of agricultural land contaminated with heavy natural radionuclides (210Pb,210Po,226Ra,232Th,238U) was considered. Algorithm of decision making support on advisability of rehabilitation of mentioned land was suggested. Proposed algorithm was tested on the base of agricultural farmlands located in the affected zone of Pridneprovsky Chemicals Plant and its tailing dumps

  9. Activity levels of some radionuclides in Mariout and Brullus lakes, Egypt.

    Science.gov (United States)

    Dar, Mahmoud A; El Saharty, Abeer A

    2013-11-01

    Mariout and Brullus are two of the highly fish-productive lakes in the northern coast of Egypt along the Mediterranean Sea. They are widely used to drain industrial wastes, sewage and agriculture drainage. The activities of (238)U, (232)Th, (40)K and (137)Cs were measured in the uppermost part of the surface sediments of the two lakes, using gamma-ray spectrophotometry. Brullus Lake recorded significantly higher (238)U and (232)Th and lower (40)K (17.22±2.49, 10.03±0.56 and 299.70±17.78 Bq kg(-1)) than Mariout Lake (12.65±1.53, 7.24±0.76 and 518.75±46.24 Bq kg(-1), respectively). Cesium-137 shows nearly equal activities in both lakes (3.33±0.46 and 3.68±0.70 Bq kg(-1), respectively). Activity distributions of (238)U and (232)Th in the sediments of Mariout Lake show a significant increase to the west, southwest and northeast, (40)K activity increased westwards, while the (137)Cs level was increased to the east and northeast, indicating agriculture drainage, industrial wastes and lands reclamation around the lake. At Brullus Lake, the activity trends of (238)U, (232)Th, (40)K and(137)Cs were increasing to the west and south towards the agriculture and industrial waste-water-feeding drains. PMID:23630385

  10. Natural radionuclides and dose estimation in natural water resources from Elba protective area, Egypt

    International Nuclear Information System (INIS)

    The concentrations of the natural radionuclides 226Ra, 232Th and 40K in 15 different water samples from Elba protective area, south-eastern desert of Egypt, have been determined using NaI(Tl) detector. Gamma ray spectrometric analysis was performed and the concentrations obtained for each of the radionuclides expressed in Bq l-1 ranging from 1.6 to 11.1 for 226Ra, 0.21 to 0.97 for 232Th and 9.1 to 23 for 40K. A reasonable correlation was found between 226Ra, 232Th concentrations and pH, although no general trend was observed with conductivity and total dissolved solids. The mean effective doses of 0.56 mSv y-1 for 226Ra, 0.065 mSv y-1 for 232Th and 0.04 mSv y-1 for 40K were estimated for the ingestion of these waters by adults. (authors)

  11. 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

  12. 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

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

    Science.gov (United States)

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

    2015-01-01

    The Russian Emission Detector 100 (RED-100) under construction at the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) is designed to detect the presently undiscovered effect of coherent neutrino scattering. One of the factors limiting the sensitivity of the detector is the spontaneous decay of uranium and thorium in the detector materials. Radioactive impurities in detector materials at levels of parts per billion can significantly affect the sensitivity. Five random samples of titanium and one of copper from materials used in the construction of the detector were selected for assay. The concentration of (232)Th and (238)U were measured by inductively coupled plasma mass spectrometry (ICP- MS) in solid titanium using both: solutions in acids and direct sampling by laser ablation (LA-ICP-MS). The LA- ICP-MS method allowed us to determine (238)U and (232)Th at subnanogram per gram levels. This method is much faster than ICP-MS with liquid injection. The titanium samples studied have impurities in the range between 1 ng g(-1) and 21 ng g(-1) for (238)U and 3 ng g(-1) and 31 ng g(-1) for (232)Th. In copper we set upper limits of 0.4 ng g(-1) for (238)U and 1 ng g(-1)for (232)Th. The total activity of the cryostat constructed from materials studied was estimated to be 43 Bq. PMID:26307714

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

    International Nuclear Information System (INIS)

    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

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

    DEFF Research Database (Denmark)

    Gäfvert, T.; Pagels, J.; Holm, E.

    2003-01-01

    for two scenarios, one realistic and one with conservative assumptions, showing that the annual committed effective dose from inhalation of Th-232, Th-230, Th-228 and Ra-228, for a full-time TIG welder, in the realistic case is below 0.3 mSv and with conservative assumptions around 1 mSv or lower...

  16. Thorium in the workplace measurement intercomparison

    International Nuclear Information System (INIS)

    The monitoring of radionuclides in the nuclear industry has been recognized as the most straightforward way of assessing health and safety issues associated with the exposure of the workforce to potentially harmful radiation doses. Much of this is achieved by measurements in the workplace itself and by the bioassay and monitoring of workers in the industry. However, there also exists a significant 'non-nuclear' industry where workers are exposed to radioactive materials, for example where this involves thorium, which is made wide use of in the aerospace and other high technology industries. As such work involves the processing of thorium bearing materials, the workforce is potentially exposed to 232Th and its daughter nuclides. Thus, to monitor the workforce effectively, it is important to be able to measure both 232Th and the decay products of 232Th where they are in an unknown state of radioactive equilibrium and this is where monitoring laboratories may experience some difficulty. Accordingly, the Health and Safety Laboratory in the UK has organized a EC wide project on the monitoring of thorium in the 'non-nuclear' workplace; this project is currently ongoing. We report the results of the first intercomparison of this project involving two solutions of 232Th, one in radioactive equilibrium and one not in equilibrium with its daughters. The results are presented with some comments on how this intercomparison has progressed and how these first results will inform the rest of the project

  17. GIS predictive mapping of terrestrial gamma radiation in the Northern State, Sudan

    International Nuclear Information System (INIS)

    This study presents the evaluation of absorbed dose in air due to gamma-emitting nuclides from 238U and 232Th series, 40K and 137Cs and the corresponding geographical information system (GIS) predictive mapping for the Northern State. Activity concentration of 238U, 232Th , 40K and 137Cs in soil samples collected from different locations have been measured using high resolution gamma spectrometry. On average, activity concentrations were 19±4 (238U), 47±11 (232Th), 317±65 (40K) and 2.26 Bq kg-1 for 137Cs. Absorbed dose rate in air at a height of 1 m above ground surface was calculated using seven sets of dose rate conversion factors (DRCFs) and the corresponding annual effective dose was estimated. On average, the values obtained fall within a narrow range of 44 and 53 nGy h-1, indicating that the variation in absorbed dose rate is insignificant for different DRCFs. The corresponding annual effective dose ranged from 53 to 65 μSv y-1. Using GIS, prediction maps for concentrations of 238U, 232Th, 40K and 137Cs were produced. Also, a map for absorbed dose rate in air at a height of 1 m above the ground level was produced, which showed a trend of increasing from the west towards south-east of the State. (authors)

  18. 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)

  19. 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).

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

    Science.gov (United States)

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

    2015-12-01

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

  1. 76 FR 31379 - Notice of Availability of Environmental Assessment and Finding of No Significant Impact for...

    Science.gov (United States)

    2011-05-31

    ...-232 (Th-232) and radium-226 (Ra-226) are provided in the revised DP. Small quantities of Th-232 and Ra... DCGLs established in the DP Revision 2 for Ra-226 and Th-232 do not exceed the trigger levels requiring... revised DP includes new site-specific soil DCGLs for Ra-226 and Th-232, to support the...

  2. A novel assay method for the trace determination of Th and U in copper and lead using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    This study describes a novel sample preparation and assay method developed, primarily in support of the MAJORANA DEMONSTRATOR neutrinoless double-beta decay experiment, for the determination of extremely low levels of Th and U in copper and lead shielding components. Meticulously clean sample preparation methods combined with anion exchange separations for analyte pre-concentration and matrix removal were developed. Quantification was performed by isotope dilution inductively coupled plasma mass spectrometry. Detection limits of 0.0084 pg 232Th/g (0.034 µBq 232Th/kg) and 0.0106 pg 238U/g (0.131 µBq 238U/kg) were determined for copper, while detection limits of 0.23 pg 232Th/g (0.94 µBq 232Th/kg) and 0.46 pg 238U/g (5.7 µBq 238U/kg) were achieved for lead. These methods allow the Majorana Collaboration to accurately assay detector components and ensure that the experiment's stringent radiopurity requirements are met

  3. 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.

  4. 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.

  5. Muon-induced fission

    International Nuclear Information System (INIS)

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

  6. 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.

  7. Investigation of gamma-ray activity and radiological hazards of the bricks fabricated around Lahore (Pakistan)

    International Nuclear Information System (INIS)

    Employing state of art measurement techniques and software, gamma ray activity due to /sup 224/Ra, /sup 232/Th and /sup 40/K have been measured from bricks fabricated around Lahore, Pakistan. External and internal hazards due to dose rate from radioactivity of bricks have calculated from several samples. (author)

  8. Population exposure to airborne thorium at the high natural radiation areas in India

    International Nuclear Information System (INIS)

    High natural radiation areas in the coastal and peninsular India were studied for airborne thorium and resultant population exposure due to inhalation. Four locations covering three states viz., Ayiramthengu and Neendakara in Kerala, Kudiraimozhi in Tamil Nadu and Bhimilipatnam in Andhra Pradesh were investigated. External gamma radiation fields 1 m above the monazite ore bodies ranged from 200 to 3000 nGy h-1. Soil samples showed 232Th specific activity varying from 0·1 to 1·5 Bq g-1 with surface alpha activity in the range of 1·0-12·5 Bq cm-2. Suspended particulates in the samples ranged from 60-140 μg m-3 with 232Th showing a wider variation of -3. There was poor correlation between suspended particulates and long-lived alpha airborne activity (r=-0·3). The resuspension factors for 232Th were in the range of 1·5x10-8-7·9x10-7 cm-1. Higher resuspension was correlated with dry sand dunes. The upper limits for Committed Effective Dose (CED) due to inhalation of airborne 232Th at the respective high natural radiation areas were estimated to range from 50±30 to 300±130 μSv (5-30 mrem) per year per adult member of public assuming an activity median aerodynamic diameter of 1 μm for the airborne particulates. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. 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.

  10. 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.

  11. 230Th/U-dating of a late Holocene low uranium speleothem from Cuba

    International Nuclear Information System (INIS)

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

  12. Hydride interference on the determination of minor actinide isotopes by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Hydrogen adducts of the major naturally occurring actinide isotopes 232Th and 238U were studied using an inductively coupled plasma mass spectrometer. The hydride:atomic ion ratios for both elements varied as a function of the parameters that were studied, i.e., nebulizer flow rate, solution uptake rate and desolvation conditions. When the instrument sensitivity for U and Th was optimized, 232ThH+:232Th+ was found to be (3.9±0.2) x 10-5 with pneumatic nebulization and (2.10±0.07) x 10-5 with ultrasonic nebulization. Under the same conditions, 238UH+:238U+ was found to be (3.2±0.2) x 10-5 and (1.8±0.1) x 10-5 using pneumatic and ultrasonic nebulization, respectively. Conditions that reduced hydrogen number density and/or increased plasma temperature decreased the hydride:atomic ion ratio. Such conditions are best if 233U and 239Pu are to be determined in the presence of 232Th and 238U. (Author)

  13. 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,

  14. HEU age determination

    International Nuclear Information System (INIS)

    A technique has been developed to determine the Highly Enriched Uranium (HEU) Age which is defined as the time since the HEU was produced in an enrichment process. The HEU age is determined from the ratios of relevant uranium parents and their daughters viz 230Th/234U and 231Pa/235U. Uranium isotopes are quantitatively measured by their characteristic gammas and their daughters by alpha spectroscopy. In some of the samples where HEU is enriched more than 99%, the only mode of HEU age determination is by the measurement of 231Pa since there is negligible quantity of 230Th due to very low atom concentrations of 234U in the sample. In this paper we have presented data and methodology of finding the age of two HEU samples

  15. Measurements of radium in water using impregnated fibers

    International Nuclear Information System (INIS)

    The technique perfected by Moore and Reid for sampling radium in seawater is well adapted for environmental sampling. Using this method, we have examined runoff from mine tailings and have observed relatively high amounts of 223Ra (from the 235U series). Apparently the fiber is able to absorb a precursor, 231Pa or 227Ac, and hence retains the 223Ra concentrations for long storage periods. Examples of high-resolution alpha spectrometry of these activities are presented

  16. 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.

  17. 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.

  18. Transfer-factors for radionuclides in the coal-fired power plants environments in Serbia

    International Nuclear Information System (INIS)

    Full text: During the coal combustion in power plants, radionuclides are distributed in solid and gaseous combustion products and discharged into environment. Radioactivity monitoring of coal-fired power-plants environments (PP Nikola Tesla, PP Kolubara, PP Morava and PP Kostolac) in Serbia was carried out during 2003-2006. Here are presented results concerning the soil-plant and ash-plant systems. Plant samples growing at the soil and ash disposals are analyzed by gamma spectrometry (HPGe detector, relative efficiency 23%) and corresponding transfer factors (TF) for natural isotopes 226Ra, 232Th and 40K were calculated and discussed. Obtained concentrations values of naturally occurring radionuclides are in following ranges: (0.4 - 29) Bq/kg 226Ra, (0.16 - 23) Bq/kg 232Th, (245 - 1274) Bq/kg 40K, (1.7 - 30) Bq/kg 238U, (0.08 - 4.7) Bq/kg 235U, (5.6 - 95) Bq/kg 210Pb; (28 - 288) Bq/kg 7Be and man-made 137Cs in range 0.06 - 2.8 Bq/kg. Ash-to-plant and soil-to-plant transfer factors for 226Ra, 232Th and 40K are calculated for several sampling points. Values for both ash-to-plant and soil-to-plant transfer factors are much higher for 40K than 226Ra and 232Th probably due to different assimilation mechanisms of these elements by plants. Analyzed radionuclides have higher concentrations in the ash disposal than soil, and corresponding transfer-factors values obtained for ash-plant systems (ranged from 0,007 to 0,179 for 226Ra, from 0,015 to 0,174 for 232Th and from 0,418 to 2,230 for 40 K) are higher, indicating that there is no limit value for absorption in plants. (author)

  19. Assessment of radionuclide and metal contamination in a thorium rich area in Norway.

    Science.gov (United States)

    Popic, Jelena Mrdakovic; Salbu, Brit; Strand, Terje; Skipperud, Lindis

    2011-06-01

    The Fen Central Complex in southern Norway, a geologically well investigated area of magmatic carbonatite rocks, is assumed to be among the world largest natural reservoirs of thorium ((232)Th). These rocks, also rich in iron (Fe), niobium (Nb), uranium ((238)U) and rare earth elements (REE), were mined in several past centuries. Waste locations, giving rise to enhanced levels of both radionuclides and metals, are now situated in the area. Estimation of radionuclide and metal contamination of the environment and radiological risk assessment were done in this study. The average outdoor gamma dose rate measured in Fen, 2.71 μGy h(-1), was significantly higher than the world average dose rate of 0.059 μGy h(-1). The annual exposure dose from terrestrial gamma radiation, related to outdoor occupancy, was in the range 0.18-9.82 mSv. The total activity concentrations of (232)Th and (238)U in soil ranged from 69 to 6581 and from 49 to 130 Bq kg(-1), respectively. Enhanced concentrations were also identified for metals, arsenic (As), lead (Pb), chromium (Cr) and zinc (Zn), in the vicinity of former mining sites. Both radionuclide and heavy metal concentrations suggested leaching, mobilization and distribution from rocks into the soil. Correlation analysis indicated different origins for (232)Th and (238)U, but same or similar for (232)Th and metals As, Cr, Zn, nickel (Ni) and cadmium (Cd). The results from in situ size fractionation of water demonstrated radionuclides predominately present as colloids and low molecular mass (LMM) species, being potentially mobile and available for uptake in aquatic organisms of Norsjø Lake. Transfer factors, calculated for different plant species, showed the highest radionuclide accumulation in mosses and lichens. Uptake in trees was, as expected, lower. Relationship analysis of (232)Th and (238)U concentrations in moss and soil samples showed a significant positive linear correlation. PMID:21556423

  20. 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.

  1. Proton-induced fission of heavy nuclei at intermediate energies

    CERN Document Server

    Deppman, A; Guimaraes, V; Karapetyan, G S; Balabekyan, A R; Demekhina, N A

    2013-01-01

    The intermediate energy proton-induced fission of 241Am, 238$U and 237$Np is studied. The inelastic interactions of protons and heavy nuclei are described by a CRISP model, in which the reaction proceeds in two steps. The first one corresponds fast cascade, where a series of individual particle-particle collisions occurs within the nucleus. It leaves a highly excited cascade residual nucleus, assumed to be in thermal equilibrium. Subsequently, in the second step the excited nucleus releases its energy by evaporation of neutrons and light charged particles as well. Both the symmetric and asymmetric fission are regarded, and the fission probabilities are obtained from CRISP code calculations, by means of statistical weighting factors. The fission cross sections, the fissility of the fissioning nuclei, and the number of nucleons lost by the target - before and after fission - are calculated and compared to experiments for 660 MeV protons incident on 241Am, 238$U and 237$Np. Some of the model predictions are in f...

  2. Radionuclide migration experiments in a natural fracture in a quarried block of granite

    International Nuclear Information System (INIS)

    A radionuclide migration experiment was performed over a distance of 1 m in a natural fracture in a quarried block of granite. The fracture in the block was characterized hydraulically by measuring the pressure drop in borehole-to-borehole pump tests. The effective fracture volume in the block was ∼100 mL. A silicone coating was applied to the exterior, and the block was immersed in a tank of water to which hydrazine was added to provide a chemically reducing barrier. Migration experiments were performed at a flow rate of 2.2 mL h-1 using 85Sr, 131I,137Cs, 144Ce, 152Eu, 237Np and 238Pu. A total of 9.5 L of groundwater was pumped through the fracture, corresponding to ∼95 fracture volumes. Only 85Sr, 131I, 137Cs, 237Np and 238Pu were observed in the eluent. Scanning of the fracture surface at the end of the migration experiment showed limited mobility of α-emitting radionuclides and of the rare-earth elements, consistent with static sorption data obtained on representative fracture surface material. The mobility of 137Cs was higher than that of the rare-earth elements, but it was lower than that of 85Sr. When samples of fracture-coating material were separated into fractions with different specific gravity, there was a clear indication of radionuclide association with mineral groups. (author)

  3. Radionuclide migration experiments in a natural fracture in a quarried block of granite

    Science.gov (United States)

    Vandergraaf, Tjalle T.; Drew, Douglas J.; Masuda, Sumio

    1996-02-01

    A radionuclide migration experiment was performed over a distance of 1 m in a natural fracture in a quarried block of granite. The fracture in the block was characterized hydraulically by measuring the pressure drop in borehole-to-borehole pump tests. The effective fracture volume in the block was ˜ 100 mL. A silicone coating was applied to the exterior, and the block was immersed in a tank of water to which hydrazine was added to provide a chemically reducing barrier. Migration experiments were performed at a flow rate of 2.2 mL h -1 using 85Sr, 131I, 137Cs, 144Ce, 152Eu, 237Np and 238Pu. A total of 9.5 L of groundwater was pumped through the fracture, corresponding to ˜95 fracture volumes. Only 85Sr, 131I, 137Cs, 237Np and 238Pu were observed in the eluent. Scanning of the fracture surface at the end of the migration experiment showed limited mobility of α-emitting radionuclides and of the rare-earth elements, consistent with static sorption data obtained on representative fracture surface material. The mobility of 137Cs was higher than that of the rare-earth elements, but it was lower than that of 85Sr. When samples of fracture-coating material were separated into fractions with different specific gravity, there was a clear indication of radionuclide association with mineral groups.

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

    International Nuclear Information System (INIS)

    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 129I, 237Np and 243Am samples and of fission reaction rates in 235U, 237Np and 243Am 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

  5. The effects of actinide separation on the radiological consequences of geologic disposal of high-level waste

    International Nuclear Information System (INIS)

    It has often been suggested that the potential hazard to man from the disposal of high-level radioactive waste could be reduced by removing a substantial fraction of the actinide elements. In this report the effects of actinide separation on the radiological consequences of one of the disposal options currently under consideration, that of burial in deep geologic formations, are examined. The results show that the potential radiological impact of geologic disposal of high-level waste arises from both long-lived fission products and actinides (and their daughter radionuclides). Neither class of radionuclides is of overriding importance and actinide separation would therefore reduce the radiological impact to only a limited extent and over limited periods. There might be a case for attempting to reduce doses from 237Np. To achieve this it appears to be necessary to separate both neptunium and its precursor element americium. However, there are major uncertainties in the data needed to predict doses from 237Np; further research is required to resolve these uncertainties. In addition, consideration should be given to alternative methods of reducing the radiological impact of geologic disposal. The conclusions of this assessment differ considerably from those of similar studies based on the concept of toxicity indices. Use of these indices can lead to incorrect allocation of research and development effort. (author)

  6. Transuranium reference measurements and reference materials

    International Nuclear Information System (INIS)

    During the 30 years of its existence, the Central Bureau for Nuclear Measurements has been involved in numerous high-accuracy investigations of mainly nuclear properties of elements important for the nuclear fuel cycle and for application of relevant radionuclides. This paper reports that these studies were made possible by the availability of particle accelerators (150-MeV electron linear accelerator; 3.7- and 7-MV Van de Graaff accelerators) as neutron sources and the use of specialized laboratories for the preparation, characterization, and manipulation of radioactive samples. Examples of investigations with plutonium and neptunium are capture and fission cross sections of 239Pu at very low energies, spontaneous fission fragment mass and energy distributions of 242Pu at very low energies, spontaneous fission fragment mass and energy distributions of 242Pu, alpha-particle and gamma-ray spectra of 237Np, half-life of 241Pu, use of 237Np in reactor neutron dosimetry, preparation and characterization of plutonium oxide reference materials for nondestructive analysis, and demonstration of the potential of synthetic isotope mixtures for analytical control of the nuclear fuel cycle

  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. 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.

  9. 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

  10. Thorium determination in intercomparison samples and in some Romanian building materials by gamma-ray spectrometry

    International Nuclear Information System (INIS)

    Thorium content in zircon sand, thorium ore and a thorium liquid sample, as well as in some Romanian building materials: sand, wood, tufa, asbestos-cement, cement mill dust, fly coal ash, bricks and tile (28 samples) was determined by gamma-ray spectrometry. For the building materials, 226 Ra, 40 K and 137 Cs specific activities were also measured. All samples were kept tightly closed in the pots for about one month, to allow that the radioactive equilibrium among the gaseous radionuclides 222 Rn (238 U series), 220 Rn (232 Th series) and their daughter products be reached. 232 Th activity concentration was calculated from its daughter products 228 Ac, 212 Pb, 212 Bi and 208 Tl, assuming radioactive equilibrium among all 232Th decay chain isotopes. The activity concentrations of 226 Ra was calculated by 214 Pb and 214 Bi daughter products, assuming radioactive equilibrium among all 226 Ra decay chain isotopes. Zircon sand, thorium ore and a thorium liquid sample were analyzed in the frame of the European Commission Project 'Thematic network on the analysis of thorium and its isotopes in workplace materials', coordinated by the Health and Safety Laboratory HSL, Sheffield, United Kingdom. Thorium nitrate solution containing 232 Th in equilibrium with its daughter products and the two thorium minerals (without any prior treatment) were prepared as test samples by the Centre for Ionizing Radiation Metrology at the UK National Physical Laboratory (NPL), Teddington, England. The obtained 232 Th results are in good agreement with those of NPL for the liquid and ore samples (analyst/NPL ratios of 0.97 and 1.05, respectively) and rather good agreement for zircon sand (analyst/NPL ratio of 1.20). Sand, wood, tufa, asbestos-cement, cement mill dust, fly coal ash, tile, red and autoclaved cellular concrete (ACC) bricks collected from building material factories in different zones of Romania were investigated for natural and artificial radioactivity. The results were compared

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

    International Nuclear Information System (INIS)

    Full-text: The annual intake of four naturally occurring radionuclides 226Ra, 238U, 232Th and 40K from powdered milk, wheat flour, tea and coffee for Malaysian population were estimated using gamma spectrometry system. The radionuclides annual intake of 226Ra ranged from 6 to 35.7 Bq, 232Th ranged from 7.6 to 57.7 Bq, 238U ranged from 6.3 to 63.7 Bq and 40K ranged from 771.8 to 1707.5 Bq for adults. The means of these intakes were 28.8 Bq for 226Ra, 38.5 Bq for 232Th, 28.1 Bq for 238U and 2921.1 Bq for the 40K. The annual intake of radionuclide for infants were found to be 66.2 Bq for 226Ra, 71.6 Bq for 232Th, 23 Bq for 238U and 7774.8 Bq for 40K. the annual internal dose for infants from the intake of powdered milk were 63.5 μSv for 226Ra, 32.2 μSv for 232Th, 2.8 μSv for 238U and 326.5 μSv for 40K. The measured values also gives annual internal dose of 13.7 μSv 226Ra, 19 μSv for 232Th, 4 μSv for 238U and 24.2 μSv for 40K for adult population. The net radiological impact of these radionuclides is 425 μSv for infants and 60.9 μSv for adults. This value gives cancer risk factor of 1.8 x 10-3 for infants and 1.7 x 10-4 for adults. The probability of cancer risk increment is estimated as 0.18 % for infants (18 person in 10000) and 0.017 % for adults (1.7 person in 10000). Whereas ICRP cancer risk factor for general public is 2.5 x 10-3 nd the total risk involved from all natural radiation sources based on global average radiation dose of 2.4 mSv is of 6 x 10-3. The estimated cancer risk shows that probability of increase of cancer risk from intake of milk, wheat flour, tea and coffee is only a minor fraction of ICRP values. Therefore, the diet does not pose any significant health hazard and is considered safe for human consumption. (author)

  12. Gamma radioactivity in sediments of Maracaibo Lake, Venezuela

    International Nuclear Information System (INIS)

    Maracaibo Lake is located to the west part of Venezuela (see Figure), with a surface of 13.000 Km2, its coast embraces a longitude of 729 Km. This lake is the largest fresh water hydrologic basin of Venezuela and its ecosystem is subjected to intense and constant modification due to the strong oil exploitation developed in this region. Both in the coastal area and inside the lake, the petroleum extraction process induces modification in the ecosystem. Radioactive content characterization was carried out in coastal sediments of Maracaibo Lake, measuring the specific activity of the following elements: 40K, gamma emitters of the natural radioactive series (238U and 232Th) and radioactive elements of anthropogenic origin (137Cs, among others) and cosmogenic as Berilium-7. The radioactive disequilibrium in the 238U and 232Th series was evaluated. Surface samples (from depth up to 5 cm) of the sediments along the coast were recollected and measured by high resolution gamma spectroscopy using a HpGe detector of approximately 2 KeV resolution for the 1,33 MeV 60Co peak and efficiency higher than 20% (supplied under the IAEA Technical Co-operation Project VEN/9/005). The 137Cs concentrations ranged in the interval 0,5-13,1 Bq/kg, while those of natural radionuclides are 238U (2,12 - 5,01 ppm), 232Th (6,71-38,58 ppm) and 40K (1,05-3,64%), assuming radioactive equilibrium in samples. Between elements of the 238U series high correlation was obtained while it is low between those of the 232Th series, being evidenced radioactive disequilibrium in this series. We found high positive correlation between 40K and elements of the 232Th series, and in turn low and negative with those of the 238U series. 232Th and 238U correlate negatively one to each other. This coastal sediment characterization of Maracaibo Lake allowed us to obtain a map of radioactive levels in these areas, which will serve as reference for future investigations. Reference sample for this study were supplied by

  13. Implantation of alpha spectrometry methodology for the determination of U and Th isotopes in igneous rocks: application to the study of radioactive desequilibrium in the Trindade Island, Brazil

    International Nuclear Information System (INIS)

    This work describes the implementation of experimental procedures for alpha spectrometry measurement of 238U, 234U and 230Th activities in silicates. The best experimental conditions were defined using 233U, 232U and 229Th radioactive tracers and simulating the usual conditions found in processing silicates. The chemical procedures consists of the following steps: radioactive tracer addition and sample dissolution by acid digestion, U and Th pre-concentration by co-precipitation, element separation and purification by ion exchange chromatography and electrodeposition in inox steel disks. In order to evaluate its effectiveness, the procedure was applied to the Brazilian geological standards BB-1 (basalt) and GB-1 (granite). The obtained chemical yields for uranium and thorium are of about 60% and 70%, respectively, for both matrices. The described methodology furnishes activity measurements with less than 4% relative precision and accuracies of about 1%, that are essential for petrogenetic applications. The 238U and 232Th series disequilibrium conditions were investigated by alpha spectrometry, together with neutron activation analysis and natural gamma-ray spectrometry. 234U/238U, 238U/232Th and 230Th/232Th activity ratios and the 234Th, 214Pb, 214Bi, 235U, 228Ac, 212Pb, 212Bi and 208Tl specific activities were obtained. These results were interpreted with the help of additional constraints given by the larger and smaller elements concentrations, measured by X-ray fluorescence. The 232Th series is in secular radioactive equilibrium in all analysed samples. In the case of the 238U series, the equilibrium condition was verified, as expected, in the oldest rocks from the Trindade Island (Trindade Complex and Desejado Sequence). On the other hand, the results show that, in the samples from the last three volcanic episodes in the island (Morro Vermelho Formation, Valado Formation and Vulcao do Paredao), the 230Th and 238U are not in equilibrium. Furthermore the three

  14. In-situ gamma-ray survey of rare-earth tailings dams--A case study in Baotou and Bayan Obo Districts, China.

    Science.gov (United States)

    Li, Baochuan; Wang, Nanping; Wan, Jianhua; Xiong, Shengqing; Liu, Hongtao; Li, Shijun; Zhao, Rong

    2016-01-01

    An in-situ gamma-ray spectrometer survey with a scintillation detector of NaI(Tl) (Φ75 mm × 75 mm) was carried out in the Baotou and Bayan Obo Districts in order to estimate the levels of natural radionuclides near rare-earth (RE) tailings dams. In the RE tailings dam of Baotou, the mean concentrations of (238)U and (232)Th were 3.0 ± 1.0 mg/kg (range: 1.9-4.6 mg/kg) and 321 ± 31 mg/kg (range: 294-355 mg/kg), respectively. In the Bayan Obo tailings dam, the mean concentrations of (238)U and (232)Th were 5.7 ± 0.5 mg/kg (range: 5.3-6.1 mg/kg) and 276 ± 0.5 mg/kg (range: 275.5-276.3 mg/kg), respectively. The average (232)Th concentrations in the mining areas of the Bayan Obo Mine and the living areas of the Bayan Obo Town were 18.7 ± 7.5 and 26.2 ± 9.1 mg/kg, respectively. The (232)Th concentration recorded in the tailings dams was much higher than the global average (7.44 mg/kg). Our investigation shows that the (232)Th concentration in the tailings in the Baotou dam was 34.6 times greater than that in the local soil (in Guyang County); the average concentrations of (232)Th in the soil in the Baotou District and Bayan Obo Districts were about 1.35 and 2.82 times greater, respectively, than that in the soil in Guyang County. Based on our results, the highest estimated effective dose due to gamma irradiation was 1.15 mSv per year, estimated from the data observed in the Baotou tailings dams. The results of this preliminary study indicate the potential importance of radioactivity in RE tailings dams and that remedial measures may be required. PMID:26555365

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

    International Nuclear Information System (INIS)

    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

  16. Determination of 236U and transuranium elements in depleted uranium ammunition by α-spectrometry and ICP-MS

    International Nuclear Information System (INIS)

    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 (236U, 239Pu, 240Pu, 241Am, and 237Np) in the ammunition. In this work the analysis of actinides by α-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. 242Pu and 243Am 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 106; after elution plutonium was determined by ICP-MS (239Pu and 240Pu) and α-spectrometry (239+240Pu) 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 240Pu/239Pu isotope ratio in one penetrator sample (0.12±0.04) was significantly lower than the 240Pu/239Pu ratios found in two soil samples from Kosovo (0.35±0.10 and 0.27±0.07). 241Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 107. The concentration of 241Am in the penetrator samples was 2.7 x 10-14 g g-1 and -15 g g-1. In addition 237Np was detected at ultratrace levels. In general, ICP-MS and α-spectrometry results were in good agreement.The presence of anthropogenic radionuclides (236U, 239Pu,240Pu, 241Am, and 237Np) 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. (orig.)

  17. 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

  18. Monitoring of natural radioactivity in manganese ore

    International Nuclear Information System (INIS)

    The natural radionuclides (238U, 232Th, and 40K) contents of Manganese ore collected by Sinai Manganese Company in Egypt-Cairo have been determined by low background spectroscopy using hyper-pure germanium (HPGe) detector. The mean activities due to the three radionuclides (238U, 232Th, and 40K) were found to be 3543 ± 106, 222 ± 6.6 and 3483 ± 104 Bq/kg, respectively. The absorbed dose rates due to the natural radioactivity in samples under investigation ranged from 1522 ± 45 to 1796 ± 53 nGy/h. The radium equivalent activity varied from 3807 ± 114 to 4446 ± 133 Bq/kg. Also, the representative external hazard index values for the corresponding samples were estimated.

  19. A novel assay method for the trace determination of Th and U in copper and lead using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    This study describes a novel sample preparation and assay method developed in support of the MAJORANA DEMONSTRATOR experiment for the determination of thorium and uranium levels in copper and lead shielding components. Meticulously clean sample preparation methods combined with novel anion exchange separations for analyte pre-concentration and matrix removal were developed. Quantification was performed by inductively coupled plasma mass spectrometry. Detection limits of 0.0084 pg 232Th/g and 0.0106 pg 238U/g were determined for copper, while detection limits of 0.23 pg 232Th/g and 0.46 pg 238U/g were achieved for lead. These methods allow the Majorana Collaboration to accurately assay detector components and ensure that the experiment's stringent radiopurity requirements are met.

  20. 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.)

  1. 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

  2. Thorium in human tissues

    International Nuclear Information System (INIS)

    The human tissue contents of natural alpha-emitting isotopes of thorium (228Th, 230Th, and 232Th) were determined in six sets of samples from Colorado and two lung samples from New York. Lung, lymph nodes from lung, liver, kidney, spleen, and bone were obtained at autopsy, and radiochemical analyses were made. Thorium-230 and 232Th are distributed similarly in the body, with major amounts present in bone (60%), followed by lung (20%) and lymph nodes (6%). Concentration decreased in the order lymph nodes > lung > bone > liver, kidney, and spleen. Thorium-228 is found primarily in bone (95%), and concentration decreases in the order lymph nodes > bone > lung > liver, kidney, and spleen. For all isotopes the median ratio of concentration in lymph nodes to lung was about 15. Thorium-230 was significantly increased in lung and skeleton samples from an underground hard-rock miner

  3. Hydrogeochemical utilization of natural isotopes from U(4n+2) and Th(4n) series at Morro do Ferro, Pocos de Caldas (MG)

    International Nuclear Information System (INIS)

    Uranium and thorium isotopic analysis were performed on well spoils of the main ore body at Morro do Ferro, Pocos de Caldas (MG), using groundwater from several boreholes in the area and surface water from a steam that originates at the base of the hill. For extraction of uranium and thorium a long chemical process was applied to samples; activities of 228Th and 232 Th isotopes (4n series) and also of 238U, 234U and 230Th isotopes (4n+2 series)were determined by the alpha spectrometry method. The ratios 234U?238U determined for well spoils did not show marked disequilibria between these isotopes. However, the ratios 228Th/232Th and 230Th/234U obtained in some samples showed a high disequilibrium between these isotopes, associated with the presence of possible zones of removal of uranium and precipitation of radium.(author)

  4. Radioactivity of beach sand in the south western coast of Sri Lanka

    International Nuclear Information System (INIS)

    The activity concentrations and effective dose rates due to 232Th, 238U and 40K were determined for sand samples collected along the coastal strip from Crow Island to Beruwala, a part of south western coast of Sri Lanka, using a high-purity germanium detector. The ranges and the mean activity concentrations measured were (11-19 600, 2100), (7-3150, 450) and (14-1210, 220) Bq kg-1 for 232Th, 238U and 40K, respectively. The effective annual gamma dose in the area ranged from 0.004 to 16.8 mSv y-1. For 21 % of the locations, the annual effective dose determined from the activity concentrations exceeded the average worldwide exposure of 2.4 mSv y-1. (authors)

  5. Radiological Impact of Phosphogypsum Application in Agriculture

    International Nuclear Information System (INIS)

    Phosphogypsum (PG) contains radionuclides from 238U and 232Th decay series. Due to the presence of these radionuclides, many countries restricted the use of PG in agriculture, however there is not such restriction in Brazil. The main objective of this work was to evaluate the impact of PG application on 226Ra (238U) and 228Ra (232Th) concentrations in soil. Gamma-spectrometry was carried out using HPGe detector. No increment of 226Ra and 228Ra was observed for increasing PG doses. Average values found for 226Ra and 228Ra were respectively 37 Bq kg-1 and 57 Bq kg-1. The results showed that the increasing PG doses in the specific conditions of the experiment did not cause a significant increment of radionuclides.

  6. Investigation of natural radioactivity levels in water around Kadugli, Sudan

    International Nuclear Information System (INIS)

    Surface water from Miri Lake and groundwater from around Kadugli (West-Central Sudan) obtained by means of hand-pumps was analysed for 238U, 226Ra, 222Rn, and 232Th activity concentrations. The surface water showed very low levels of radionuclide concentrations: -1 for 238U, 226Ra, 222Rn, and 232Th, respectively. Groundwater revealed a significant amount of natural radioactivity (16.1-1720, 7.7-14.3, 3000-139,000, -1) respectively. The overall annual effective dose was below the WHO reference dose level of 0.1 mSv yr-1 except in one groundwater sample with an associated dose of 0.7 mSv yr-1

  7. Osnovnye zakonomernosti raspredelenija, migracii i nakoplenija radionuklidov v donnyh otlozhenijah Baltijskogo morja [The basic patterns of the distribution, migration and accumulation of radionuclides in the bottom sediment of the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Grigoryev Andrey

    2011-01-01

    Full Text Available This paper focuses on the impact of certain factors on the contemporary distribution of natural (226Ra, 232Th, 40К and anthropogenic (137Cs, 60Co radionuclides in the sediments of the Baltic Sea. The results of the study suggest that the distribution of 137Cs is determined by the content of hydromica of silty-clay and clay grain-size fractions, while radiocaesium is mainly accumulated by silty fractions. The accumulation of 226Ra by bottom sediments is mainly determined by the pH geochemical barrier at the water-seafloor boundary. The accumulation of 232Th occurs mainly in clayey fractions of the sediment. The distribution and accumulation of 40K is predominantly determined by the ratio of potassium contained in hydromica minerals. Significant 60Co activity was registered only in a few samples.

  8. Comparative study of the natural radioactivity of some selected rocks from Egypt and Germany

    International Nuclear Information System (INIS)

    The radioactivity contents of various radionuclides in rocks play an important role in health physics and geo-scientific research. The naturally occurring radionuclides 226Ra, 232Th and 40K are the main sources of radiation in soil and rocks from which traditional building materials are derived. These radionuclides pose exposure risks externally due to their gamma-ray emissions and internally due to radon and its progenies, which emit alpha particles. The activity concentration (Bq/kg) in igneous and metamorphic rock samples from different locations in Egypt and Germany has been analysed. The concentration values of samples for 226Ra, 232Th and 40K were found in the range of 3.9 : 57.4, 3.2: 53.4 and 202: 1211 in Egypt and 5.1 : 76, 3.4 : 70 and 10: 2070, respectively in Germany. Even though these radionuclides are widely distributed, their concentrations depend on the local geological conditions. (author)

  9. Lognormal distribution of natural radionuclides in freshwater ecosystems and coal-ash repositories

    International Nuclear Information System (INIS)

    This study summarizes and analyses data for natural radionuclides, 40K, 226 Ra and 'Th, measured by gamma spectrometry in water samples, sediments and coal-ash samples collected from regional freshwater ecosystems and near-by coal-ash repositories during the last decade, 1986-1996, respectively. The frequency plots of natural radionuclide data, for which the hypothesis of the regional scale log normality was accepted, exhibited single population groups with exception of 226Ra and232Th data for waters. Thus the presence of break points in the frequency distribution plots indicated that 226Ra and 232Th data for waters do not come from a single statistical population. Thereafter the hypothesis of log normality was accepted for the separate population groups of 226 Ra and '-32 Th in waters. (authors)

  10. Dig-face monitoring during excavation of a radioactive plume at Mound Laboratory, Ohio

    International Nuclear Information System (INIS)

    A dig-face monitoring system consists of onsite hardware for collecting information on changing chemical, radiological, and physical conditions in the subsurface soil during the hazardous site excavation. A prototype dig-face system was take to Mount Laboratory for a first trial. Mound Area 7 was the site of historical disposals of 232Th, 227Ac, and assorted debris. The system was used to monitor a deep excavation aimed at removing 227Ac-contaminated soils. Radiological, geophysical, and topographic sensors were used to scan across the excavation dig-face at four successive depths as soil was removed. A 3-D image of the contamination plumes was developed; the radiation sensor data indicated that only a small portion of the excavated soil volume was contaminated. The spatial information produced by the dig-face system was used to direct the excavation activities into the area containing the 227Ac and to evaluate options for handling the separate 232Th plume

  11. Radioactivity in Zircon from Jos, Central Nigeria

    International Nuclear Information System (INIS)

    Mining and processing of zircon along with other minerals, generally for export purposes, have been taking place in Jos, central Nigeria, for several decades. Over the years, there has been increasing concern about the radiological impact resulting from these activities. A previous assessment in the vicinity of processing areas reported an annual dose of 50 mSv which by far exceeds the 1 mSv dose limit for members of the public. In the study, the activity concentrations of 238U and 232Th in 28 samples of zircon from Jos were determined using neutron activation analysis. The results gave concentrations of 466 μg/g (5.75 Bq/g) for 238U and 7054 μg/g (28.62 Bq/g) for 232Th. These results complement the results of earlier assessments and may assist in the proper management of these activities and the choice and implementation of appropriate protective measures. (author)

  12. Transfer of Radioactivity in the Treatment of Wastewater by Phosphate

    International Nuclear Information System (INIS)

    Radionuclides of natural, terrestrial origin are ubiquitous in the environment and contribute significantly to external and internal doses to the population. Of particular importance are the solid radionuclides belonging to the 238U and 232Th series which are present in soil and rocks. The aim of this work was to study the transfer of 238U and 232Th during the treatment of wastewater by infiltration percolation through a phosphate bed. To assess radiation dose due to the treated water which is used in agriculture and for the irrigation of gardens in urban areas, these radionuclides have been measured in wastewater, phosphate samples and treated water by using solid state nuclear track detectors. (author)

  13. Evaluation of radionuclides content in the Near-Aral inhabited area's soils

    International Nuclear Information System (INIS)

    The soils analysis for radionuclides content determination in three inhabited areas of Near-Aral region (Shiili, Kazalinsk and Zhalagash) is carried out. In capacity of the 226Ra, 232Th, 40K, 137Cs, and radon concentrations analytical parameters were selected. A mean, minimal and maximal values of 226Ra, 232Th, 40K, 137Cs radioisotopes in the selected areas soils are presented. Results of radionuclide content researches testify about 137Cs global fallout typical levels for the Northern Hemisphere. So on the base of these data one can affirm that radiation situation in these regions is normal and radiation background level does not presents threat for human health. The indoor radon content excluding of two points does not exceeds the stated norms

  14. Determination of naturally occurring radionuclides in selected rocks from Hetaunda area, Central Nepal

    International Nuclear Information System (INIS)

    The specific activities of the naturally occurring radionuclides 238U, 232Th, and 40K were measured in rock samples from the Hetaunda area, central Nepal, by using gamma spectrometry. The specific activities were found to be in the range of 17 - 95 Bq.kg-1 for 238U, 24 - 260 Bq.kg-1 for 232Th and 32 - 541 Bq.kg-1 for 40K. From these data absorbed dose rates in air and annual effective doses were calculated and compared with respective data from the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) compilation. The results from our study open the door to the safe applicability of most of the investigated materials as a cheep building material. (author)

  15. 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

  16. Determination of naturally occurring radionuclides in selected rocks from Hetaunda area, central Nepal

    International Nuclear Information System (INIS)

    The specific activities of the naturally occurring radionuclides 238U, 232Th, and 40K were measured in rock samples from the Hetaunda area, central Nepal, using gamma spectrometry. The specific activities were found to be in the range of 17-95 Bq kg-1 for 238U, 24-260 Bq kg-1 for 232Th and 32-541 Bq kg-1 for 40K. From these data absorbed dose rates in air and annual effective doses were calculated and compared with respective data from the UNSCEAR compilation. The results from our study open the door to the safe applicability of most of the investigated materials as a cheep building material. (author)

  17. 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.

  18. 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.

  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. 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.

  1. 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.)

  2. Radiological characterization of pharmaceutical and cosmetic clays

    International Nuclear Information System (INIS)

    Natural radionuclide activity concentration (235U, 238U, 234U, 230Th, 226Ra, 232Th, 228Th, 228Ra and 40K) in clay materials used for cosmetic and medical purposes was determined by alpha and gamma spectrometry. The activity concentration resulted in the range of 0.71 and 4.42 Bq kg-1 for 235U, 15.1-91.4 and 15.3-81.6 Bq kg-1 for 238U and 234U, respectively, 18.7-72.4 Bq kg-1 for 230Th, 27.6-59.7 for 226Ra, 7.80-55.0 and 8.76-58.1 for 232Th and 228Th, 8.60-66.9 Bq kg-1 for 228Ra and 151.6-1,459 Bq kg-1 for 40K. In an oral treatment, the intake was calculated and for some radionuclides the results were higher than the annual dietary intake. (author)

  3. 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.

  4. Fission neutron statistical emission

    International Nuclear Information System (INIS)

    The statistical model approach FINESSE (FIssion NEutronS' Statistical Emission) for the description of fission neutron multiplicities, energy spectra and angular distributions is described. Based on an extended Weisskopf ansatz and on a realistic temperature distribution it provides a fragment mass number dependent description of fission neutron data. Model parameters (optical potential, n/γ competition) were fixed on the basis of the 252Cf(sf) (nuclear data standard). Combined with a phenomenological fission model for predicting relevant fragment data as function of asymmetry. FINESSE can be applied to any fission reaction of actinides in the Th-Cf region without further parameter adjustment. Results are presented for 252Cf(sf) and neutron induced fission of 235U, 239Pu, 232Th. Effects of multiple-chance fission are discussed for 232Th(n,xnf) reacation. (author). 46 refs, 11 figs

  5. Measurement of natural radioactivity and radiation hazard assessment in the soil samples of Ramanagara and Tumkur districts, Karnataka, India

    International Nuclear Information System (INIS)

    The activity concentration of primordial radionuclides, 226Ra, 232Th and 40K in soil samples of Ramanagara and Tumkur districts were determined by gamma spectrometry using HPGe detector. The average activity concentrations of 226Ra, 232Th and 40K were found to be 33.78 ± 1.99, 77.44 ± 2.37 and 791.58 ± 5.78 Bq Kg-1 respectively. The measured activity concentrations of these radionuclides were compared with world average activity concentration of soil. The radiological hazard indices of the natural radioactivity have been calculated and compared with the internationally approved values. The concentration of these radionuclides with different size and depth of the soil samples was studied. (author)

  6. 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. PMID:25500060

  7. Chemical deposition and characterization of thorium-alloyed lead sulfide thin films

    International Nuclear Information System (INIS)

    We present a chemical bath deposition process for alloying PbS thin films with 232Th, a stable isotope of thorium, to provide a model system for radiation damage studies. Variation of deposition parameters such as temperature, reagent concentrations and time allows controlling the properties of the resulting films. Small amounts of incorporated thorium (0.5%) strongly affected the surface topography and the orientation of the films and slowed down the growth rate. The Th appears to be incorporated as substitutional ions in the PbS lattice. - Highlights: • Chemical bath deposition has been used for alloying lead sulfide films with 232Th. • The effect of Th on the structural and optical properties of the films was studied. • Incorporation of Th affected surface topography, orientation, Eg and growth rate

  8. Radionuclide equilibria between the aquatic environment and fish tissues

    International Nuclear Information System (INIS)

    Equilibrium conditions are often assumed in dose and risk calculations based on the simple linear concentration factor model, a commonly used model in the study of contaminant flow through ecosystems. It has been argued that by using a power function model to describe radionuclide retention in fish, equilibrium may never be achieved under natural conditions, thereby violating the equilibrium requirement in the concentration factor model. Our results demonstrate uranium-series radionuclide equilibria in a natural population of common white sucker (Catostomus commersoni). Concentration factors indicated that 226Ra, 232Th, 230Th, and 228Th preferentially deposited in bone over muscle. Although 226Ra had the highest concentration in bone, 228Th yielded the highest concentration factors for water-to-bone transfer. 232Th may not be in equilibrium because of a growth dilution effect. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. 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.

  10. Analysis of a water moderated critical assembly with anisn-Vitamin C

    International Nuclear Information System (INIS)

    A tightly packed water moderated 233UO2--ThO2 critical assembly was analyzed with the Vitamin C library and the 1-D S/s n/ code, ANISN (S8,P3). The purpose of the study was to provide validation of this calculational model as applied to water-cooled hybrid fusion blankets. The quantities compared were the core eigenvalue and various activation shapes. The calculated eigenvalue was 1.02 +- 0.01. The 233U fission and 232Th capture shapes were found to be in good agreement (+-5%) with experiment, except near water--metal boundaries where differences up to 24% were observed. No such error peaking was observed in the 232Th fast fission shape. We conclude that the model provides good volume averaged reaction rates in water-cooled systems. However, care must be exercised near water boundaries where thermally dependent reaction rates are significantly underestimated

  11. 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.

  12. 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)

  13. 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.

  14. 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.

  15. Soudan Low Background Counting Facility (SOLO)

    International Nuclear Information System (INIS)

    The Soudan Low Background Counting Facility (SOLO) has been in operation at the Soudan Mine, MN since March 2003. In the past two years, we have gamma-screened samples for the Majorana, CDMS and XENON experiments. With individual sample exposure times of up to two weeks we have measured sample contamination down to the 0.1 ppb level for 238U / 232Th, and down to the 0.25 ppm level for 40K

  16. Characterization of the low-background gamma spectrometer at INSTEC for environmental radioactivity studies

    International Nuclear Information System (INIS)

    The capability of Low-Background Gamma Spectrometer (LBGS) at InSTEC for environmental proposes is studied. Fifty three γ-lines were fixed in the LBGS background spectrum. The Minimum Detectable Activities for 210Pb, 238U, 226Ra, 137Cs, 232Th and 40K were calculated using a Monte Carlo simulated detector volumetric efficiency. The radionuclide activities in marine sediment standard were determined by absolute and relative methods for validation. (Author)

  17. Uptake of natural and anthropogenic actinides in vegetable crops grown on a contaminated lake bed

    International Nuclear Information System (INIS)

    Activity concentrations and plant/soil concentration ratios (CRs) of 239,240Pu, 241Am, 244Cm, 232Th, and 238U were determined for three vegetable crops grown on an exposed, contaminated lake bed of a former reactor cooling reservoir in South Carolina, USA. The crops included greens and tubers of turnips (Brassica rapa var. white-globe), bush beans (Phaseolus vulgaris), and husks and kernels of sweet corn (Zea mays var. silver queen). Although all plots were fertilized, some received K2SO4, while others received no K2SO4. The K2SO4 fertilizer treatment generally lowered activity concentrations for 241Am, 244Cm, 232Th and 238U, but differences were statistically significant for 241Am and 244Cm only. Highly significant differences occurred in activity concentrations among actinides and among crops. In general, turnip greens exhibited the highest uptake for each of the actinides measured, while corn kernels had the least. For turnip greens, geometric mean CRs ranged from 2.3×10-3 for 239,240Pu to 5.3×10-2 for 241Am (no K2SO4 fertilizer). For corn kernels, geometric mean CRs ranged from 2.1×10-5 for 239,240Pu and 232Th to 1.5×10-3 for 244Cm (no K fertilizer). In general, CRs across all crops for the actinides were in the order: 244Cm>241Am>238U>232Th >239,240Pu. Lifetime health risks from consuming crops contaminated with anthropogenic actinides were similar to the risks from naturally occurring actinides in the same crops (total ∼2×10-6); however, these risks were only ∼0.3% of the risk from consuming the same crops contaminated with 137Cs. (author)

  18. Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

    OpenAIRE

    Adriana Eštoková; Lenka Palaščáková

    2013-01-01

    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 t...

  19. NATURAL RADIOACTIVITY IN SOME BUILDING MATERIALS USING A GAMMA-RAY SPECTROMETER

    OpenAIRE

    AKKURT, Iskender; Betül MAVİ

    2011-01-01

    The main reason for the natural radioactivity in the earth is decay series of 40K, 238U and 232Th radionuclides. Because all building materials are soil product, they contain these radionuclides as natural so that building materials have different amounts of radioactivity. In this study the concentrations of natural radioactivity levels of the commonly used natural building materials in Isparta region have been determined. The samples have been analysed using a NaI(Tl) ƒ×-ray spectrometer sy...

  20. Review of international normatives for natural radioactivity determination in building materials

    OpenAIRE

    Mossini Eros; Macerata Elena; Giola Marco; Mariani Mario

    2015-01-01

    Anthropogenic activities, such as high-altitude flights and living in buildings, have enhanced the public exposure to natural radiation. In particular, 40K and radionuclides belonging to 232Th and 238U decay chains are present even in building materials, and they may be considered as partially responsible for the effective dose coming from natural radioactivity. Scientists and governments have devoted great attention to the evaluation of the effects produced on the public by naturally occurri...

  1. Natural radioactivity measurement and evaluation of radiological hazards in some commercial flooring materials used in Thiruvannamalai, Tamilnadu, India

    OpenAIRE

    Senthilkumar, G.; Y. Raghu; S. Sivakumar; Chandrasekaran, A; D. Prem Anand; Ravisankar, R.

    2014-01-01

    The radioactivity concentrations of 226Ra, 232Th and 40K in some commercial flooring materials used in Tiruvannamalai, Tamilnadu, India, were measured using NaI(Tl) gamma ray spectrometer. The natural radionuclide contents, Ra equivalent activities and various hazard indices were also calculated to assess the radiation hazard. It was found that none of the results exceed the recommended limit value. All samples under investigation are within the recommended safety limit and do not pose signif...

  2. 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 ...

  3. Assessment of natural radioactivity in soil samples of Dez river sides – Khouzestan province

    OpenAIRE

    Nasri Nasrabadi; Hajialiani; Mostajaboddavati

    2015-01-01

    Geographical features of each region of the world affect the activity concentration of natural radionuclides such as uranium, thorium and potassium. In this study, 26 soil samples were randomly collected from sides of the Dez River and transferred to the Laboratory for preparation. Activity concentration of natural radioactive materials was measured using p-type HPGe detector with a 38% relative efficiency. The results indicated that radioactivity concentration of 226Ra, 232Th and 40K in soi...

  4. Assessments of radioactivity concentration of natural radionuclides and radiological hazard indices in sediment samples from the East coast of Tamilnadu, India with statistical approach.

    Science.gov (United States)

    Ravisankar, R; Chandramohan, J; Chandrasekaran, A; Prince Prakash Jebakumar, J; Vijayalakshmi, I; Vijayagopal, P; Venkatraman, B

    2015-08-15

    This paper reports on the distribution of three natural radionuclides (238)U, (232)Th and (40)K in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a NaI(Tl) detector based γ-spectrometry. The mean activity concentration is ⩽2.21, 14.29 and 360.23Bqkg(-1) for (238)U, (232)Th and (40)K, respectively. The average activity of (232)Th, (238)U and (40)K is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of (238)U, (232)Th and (40)K to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (Hex) internal hazard index (Hin), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended values. Therefore, coastal sediments do not to pose any significant radiological health risk to the people living in nearby areas along East coast of Tamilnadu. The data obtained in this study will serve as a baseline data in natural radionuclide concentration in sediments along the coastal East coast of Tamilnadu. PMID:26036177

  5. Preliminary economic evaluation of thorium based fuels in PWRs

    OpenAIRE

    Du Toit, M.H.; Cilliers, A.C.

    2014-01-01

    Many studies have proven that thorium-based fuel cycles are more expensive than current uranium fuel cycles, which is confirmed in this paper as well. This research, however, goes beyond the conventional nuclear plant refueling cycle, aiming to optimize the refueling cycle in line with specific advantages realized from the thoriumbased refueling cycle. These benefits are the good thermal neutronic characteristics of fertile 232Th and fissile 233U, resulting in longer r...

  6. 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.

  7. Naturally occurring radioactive material from the aluminium industry-a case study: the Egyptian Aluminium Company, Nag Hammady, Egypt

    Energy Technology Data Exchange (ETDEWEB)

    Abbady, Adel G E; El-Arabi, A M [Physics Department, South Valley University, Faculty of Science, Qena (Egypt)

    2006-12-15

    The activity concentrations and the gamma-absorbed dose rates of the terrestrial naturally occurring radionuclides {sup 226}Ra and {sup 232}Th were determined in samples of bauxite, alumina and aluminium dross tailings industrial waste (used to produce two types of alums) using high purity germanium (HPGe) gamma ray spectrometry. The bauxite and alumina are imported by Egyptalum (The Egyptian Aluminium Company, Nag Hammady, Egypt) from Guinea and India. The activity concentrations in the bauxite range from 29 {+-} 1 to 112 {+-} 6 Bq kg{sup -1} for {sup 226}Ra, and 151 {+-} 8 to 525 {+-} 12 Bq kg{sup -1} for {sup 232}Th, with mean values of 62 {+-} 8 and 378 {+-} 50 Bq kg{sup -1}, respectively. With respect to alumina and tail, the mean values are 5.7 {+-} 1.1 and 8.4 {+-} 0.8 Bq kg{sup -1} for {sup 226}Ra and 7.2 {+-} 1.6 and 10.7 {+-} 1.2 Bq kg{sup -1} for {sup 232}Th. Potassium-40 was not detected in any of the studied samples. The measured activity concentrations of {sup 226}Ra and {sup 232}Th in bauxite are higher than the world average while in alumina and tail they are lower. As a measure of radiation hazard to the occupational workers and members of the public, the Ra equivalent activities and external gamma dose rates due to natural radionuclides at 1 m above the ground surface were calculated. The external {gamma}-radiation doses received by the Egyptalum workers are 97, 409, 8.5 and 12.7 {mu}Sv y{sup -1} for the Guinean and Indian bauxite, the alumina and tail, respectively, which is well below the recommended allowed dose of 1 mSv y{sup -1} for non-exposed workers.

  8. Radionuclides and Radiation Indices of High Background Radiation Area in Chavara-Neendakara Placer Deposits (Kerala, India)

    OpenAIRE

    Mary Thomas Derin; Perumal Vijayagopal; Balasubramaniam Venkatraman; Ramesh Chandra Chaubey; Anilkumar Gopinathan

    2012-01-01

    The present paper describes a detailed study on the distribution of radionuclides along Chavara - Neendakara placer deposit, a high background radiation area (HBRA) along the Southwest coast of India (Kerala). Judged from our studies using HPGe gamma spectrometric detector, it becomes evident that Uranium ((238)U), Thorium ((232)Th) and Potassium ((40)K) are the major sources for radioactivity prevailing in the area. Our statistical analyses reveal the existence of a high positive correlation...

  9. Distribution, enrichment and principal component analysis for possible sources of naturally occurring and anthropogenic radionuclides in the agricultural soil of Punjab state, India.

    Science.gov (United States)

    Kumar, Ajay; Joshi, Vikram M; Mishra, Manish K; Karpe, Rupali; Rout, Sabyasachi; Narayanan, Usha; Tripathi, Raj M; Singh, Jaspal; Kumar, Sanjeev; Hegde, Ashok G; Kushwaha, Hari S

    2012-06-01

    Enrichment factor (EF) of elements including geo-accumulation indices for soil quality and principal component analysis (PCA) were used to identify the contributions of the origin of sources in the studied area. Results of (40)K, (137)Cs, (238)U and (232)Th including their decay series isotopes in the agricultural soil of Mansa and Bathinda districts in the state of Punjab were presented and discussed. The measured mean radioactivity concentrations for (238)U, (232)Th and (40)K in the agricultural soil of the studied area differed from nationwide average crustal abundances by 51, 17 and 43 %, respectively. The sequence of the EFs of radionuclides in soil from the greatest to the least was found to be (238)U > (40)K > (226)Ra > (137)Cs > (232)Th > (228)Ra. Even though the enrichment of naturally occurring radionuclides was found to be higher, they remained to be in I(geo) class of '0', indicating that the soil is uncontaminated with respect to these radionuclides. Among non-metals, N showed the highest EF and belonged to I(geo) class of '2', indicating that soil is moderately contaminated due to intrusion of fertiliser. The resulting data set of elemental contents in soil was also interpreted by PCA, which facilitates identification of the different groups of correlated elements. The levels of the (40)K, (238)U and (232)Th radionuclides showed a significant positive correlation with each other, suggesting a similar origin of their geochemical sources and identical behaviour during transport in the soil system. PMID:21893521

  10. Assessment of natural radioactivity levels and associated dose rates in soil samples from Northern Rajasthan, India.

    Science.gov (United States)

    Duggal, Vikas; Rani, Asha; Mehra, Rohit; Ramola, R C

    2014-01-01

    The analysis of naturally occurring radionuclides ((226)Ra, (232)Th and (40)K) has been carried out in 40 soil samples collected from four districts of the Northern Rajasthan, India using gamma-ray spectrometry with an NaI(Tl) detector. The activity concentrations of the samples range from 38±9 to 65±11 Bq kg(-1) with a mean value of 52 Bq kg(-1) for (226)Ra, from 8±8 to 32±9 Bq kg(-1) with a mean value of 19 Bq kg(-1) for (232)Th and from 929±185 to 1894±249 Bq kg(-1) with a mean value of 1627 Bq kg(-1) for (40)K. The measured activity concentration of (226)Ra and (40)K in soil was higher and for (232)Th was lower than the worldwide range. Radium equivalent activities were calculated for the soil samples to assess the radiation hazards arising due to the use of these soils in the construction of buildings. The calculated average radium equivalent activity was 205±20 Bq kg(-1), which is less than the recommended limit of 370 Bq kg(-1) by the Organization for Economic Cooperation and Development. The total absorbed dose rate calculated from the activity concentration of (226)Ra, (232)Th and (40)K ranges from 77 to 123 nGy h(-1) with an average value of 103 nGy h(-1). The mean external (Hex) and internal hazard indices (Hin) for the area under study were determined to be 0.55 and 0.69, respectively. The corresponding average annual effective dose was found to be 0.63 mSv. PMID:23943368

  11. Assessment of natural radioactivity levels in rocks and their relationships with the geological structure of Johor state, Malaysia.

    Science.gov (United States)

    Alnour, I A; Wagiran, H; Ibrahim, N; Hamzah, S; Elias, M S; Laili, Z; Omar, M

    2014-01-01

    The distribution of natural radionuclides ((238)U, (232)Th and (40)K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of (238)U, (232)Th and (40)K activity concentrations (67±6, 85±7 and 722±18 Bg kg(-1), respectively) were observed in the granite rock. The lowest concentrations of (238)U and (232)Th (2±0.1 Bq kg(-1) for (238)U and 2±0.1 Bq kg(-1) for (232)Th) were observed in gabbro rock. The lowest concentration of (40)K (45±2 Bq kg(-1)) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg(-1). The highest value of radium equivalent in the present study (239±17 Bq kg(-1)) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h(-1). The effective dose ranged from 5 to 138 μSv h(-1). The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed.

  12. 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

  13. Reference material for natural radionuclides in glass designed for underground experiments

    OpenAIRE

    Povinec, P.; PHAM M. K.; Busto, J.; Cerna, C.; Degering, D.; Y. Hamajima; Holy, K.; Hult, Mikael; Jeskovsky, M.; Koehler, M; Kovacik, A.; Laubenstein, Matthias; Loaiza, P.; Mamedov, F.; Marquet, C.

    2015-01-01

    A reference material designed for the determination of natural radionuclides in solid samples (glass pellets) is described and the results of certification are presented. The material has been certified for 7 natural radionuclides (40K, 226Ra, 228Ra, 228Th, 232Th, 235U and 238U). An information value is given for 210Pb. Radon (222Rn) emanation experiments showed results comparable within participating laboratories, however, the number of data and precision was too low to carry out a certifica...

  14. Exposures from thorium contained in thoriated tungsten welding electrodes.

    Science.gov (United States)

    Jankovic, J T; Underwood, W S; Goodwin, G M

    1999-01-01

    Information provided in this article can be used for estimating the radiation dose associated with the use of thoriated tungsten electrodes in tungsten inert gas welding. Area and breathing zone concentrations of 232Th generated by welding and electrode sharpening along with particle size information; isotopic composition of electrodes from two domestic manufacturers and one European manufacturer; and process variables and estimates on the number of thoriated tungsten electrodes manufactured are presented. Past literature is reviewed and compared with the results of this study. Isotopic analysis of a nominal 2% thoriated electrode found 0.6 ppm +/- 0.4 ppm 230Th and less than 0.1 ppm 228Th. Analysis of a ceriated tungsten electrode and a lanthanated tungsten electrode for 232Th found 124 ppm and 177 ppm, respectively. Electrode consumption during welding was primarily the result of tip sharpening. Less than 3% of the weight loss was attributable to the welding process. The in-mask concentration of respirable thorium particulate in the welder's breathing zone was 0.002 x 10(-12) microCi 232Th/mL. The concentration of respirable thorium particulate from electrode sharpening was 1.3 x 10(-12) microCi 232Th/mL. The measured sharpening time was 20 sec per electrode. Estimates of the activity median aerodynamic diameters for the respirable fraction of the welding and electrode sharpening aerosols were 3.5 and 5 microns, respectively, when measured in the breathing zone at 0.3 m (12 inches) from the point of operation. The respirable fraction of the total welding and sharpening aerosols was 45 and 60%. PMID:10386359

  15. The formation and decay of superheavy nuclei produced in $^{48}Ca$-induced reactions

    OpenAIRE

    Kumar, Sushil; Balasubramaniam, M.; Raj K Gupta; Munzenberg, G.; Scheid, W.

    2011-01-01

    The formation of superheavy nuclei in $^{48}Ca+^{232}Th$, $^{238}U$, $^{242,244}Pu$ and $^{248}Cm$ reactions and their subsequent decay are studied within the quantum mechanical fragmentation theory (QMFT) and the QMFT based preformed cluster-decay model (PCM) of Gupta and collaborators. According to QMFT, all these $^{48}Ca$-induced reactions are cold fusion reactions with relative excitation energies larger than for the $Pb$-induced cold fusion reactions and smaller than for the lighter bea...

  16. 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.

  17. Saturation condition and evolution of the nuclides for sub-critical system driven by accelerator

    International Nuclear Information System (INIS)

    At present work, under initial inventory with 232Th and natU, the evolution of nuclides in subcritical devices under given thermal, fast, hardening fast and fission neutron field are studied without the detail structure of sub-critical device and the burn-up being considered. It is supposed that the subcritical reactor consists of uniform in which the flux of neutron is homogeneous. The fissile nuclides breeding, equilibrium condition, minor activity (MA) accumulation and transmutation, are studied. (author)

  18. Assessment of natural radionuclide levels in Pakistani foodstuffs and associated radiation doses

    International Nuclear Information System (INIS)

    A comprehensive study for the assessment of natural radionuclides (40K, 238U, 226Ra, 228Ra, and 232Th) in Pakistani food items (fruits, seasonal vegetables, beef, mutton, poultry meat and eggs) and drinks samples (milk, tap water and soft drinks) was carried out in Pakistan using HPGe based high resolution gamma spectrometry. All the food items and drink samples showed detectable 40K activity, however, most of the other natural radionuclides in solid food were found to have contents below the minimum detectable activity (MDA). The range of 40K activity was found to be 0.02 to 110.5 Bq kg-1 for solid food and drink samples. The cumulative average value of 238U, 226Ra, 228Ra and 232Th were found to be 0.07, 0.03, 0.06 and 0.06 Bq kg-1 in fruits, vegetables, meat and egg samples respectively. In all milk and water based drinks the respective measured values of the mean activity of 238U, 226Ra, 228Ra and 232Th were 0.16, 0.06, 0.07 and 0.05 Bq kg-1. The annual ingestion/intakes of 40K 238U, 226Ra, 228Ra and 232Th were found to be only 0.06%, 0.007%, 0.02%, 0.03% and 0.05% of the Annual Limits on Intakes (ALIs) of these radionuclides as specified by IAEA, which shows that their contribution in Pakistani diet does not pose any significant radiological health problem. (author)

  19. 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)

  20. Enrichment and particle size dependence of polonium and other naturally occurring radionuclides in coal ash

    International Nuclear Information System (INIS)

    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 210Po using alpha spectrometry and for natural U, 226Ra, 232Th and 40K by an HPGe γ-ray spectrometer. 210Po 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 238U, 226Ra, 232Th, 40K 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. 210Po showed the largest size dependence with its concentration favoring the smaller particle size while 232Th showed least size dependence. 238U and 226Ra showed behavior intermediate to that of 210Po and 232Th. Also the correlation between sulfur content of the feed coal and activity of 210Po was investigated. Increased sulfur content in feed coal enhanced enrichment of 210Po in ash

  1. Natural Radioactivity in Soil and Water from Likuyu Village in the Neighborhood of Mkuju Uranium Deposit

    OpenAIRE

    Mohammed, Najat K.; Mazunga, Mohamed S.

    2013-01-01

    The discovery of high concentration uranium deposit at Mkuju, southern part of Tanzania, has brought concern about the levels of natural radioactivity at villages in the neighborhood of the deposit. This study determined the radioactivity levels of 30 soil samples and 20 water samples from Likuyu village which is 54 km east of the uranium deposit. The concentrations of the natural radionuclides 238U, 232Th, and 40K were determined using low level gamma spectrometry of the Tanzania Atomic Ener...

  2. 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.

  3. Impact of Thorium Capture Cross Section Uncertainty on the Thorium Utilized ADS Reactivity Calculation

    OpenAIRE

    Thanh Mai Vu; Takanori Kitada

    2014-01-01

    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 neede...

  4. Radon-222 dose rates to burrowing mammals

    OpenAIRE

    Beresford, N.A.; Barnett, C.L.; Potter, E. D.; Vives I Batlle, J.; Barlow, T.S.; Copplestone, D.

    2011-01-01

    Estimates of absorbed dose rates as a consequence of exposure of wildlife to natural background radionuclides are required to put results of assessments conducted for releases of radionuclides from licensed sites into context. There have been recent review papers in which estimated dose rates to marine, freshwater and terrestrial wildlife (specifically the ICRP Reference Animals and Plants (ICRP 2008)) from 40K and radionuclides in the 238U and 232Th series have been presented (Beresford et a...

  5. Preliminary survey of outdoor gamma dose rates in Lesvos Island (Greece).

    Science.gov (United States)

    Petalas, Anastasios B; Vogiannis, Efstratios; Nikolopoulos, Dimitrios; Halvadakis, Constantinos P

    2005-01-01

    This study reports the first attempt to record the radioactive background due to gamma radiation in Lesvos Island (Greece). The study reports the results from 335 outdoor total gamma effective dose rate measurements conducted using GPS navigation and a Geiger-Muller detector (Bicron, Micro Sievert) on the whole surface of the island together with a digital map produced by appropriate mapping GIS programme. The study also reports the measurements of outdoor gamma dose rates due to the 238U, 232Th and 40K radionuclides as estimated via in situ gamma-ray spectrometry measurements performed at 26 sites using a 3 x 3 inch NaI (thallium activated) portable detector. The results from the outdoor total gamma effective dose rates range between 0.0023 and 0.28 microSv h(-1). The highest outdoor total gamma effective dose rates (0.013-0.28 microSv h(-1)) were detected in the northeastern part of the island and the intermediate rates (0.066-0.13 microSv h(-1)) in the central region. The outdoor gamma dose rates due to 238U, 232Th and 40K radionuclides range between 1.7 +/- 0.8 and 154 +/- 7 nGy h(-1) with an average of 86 +/- 6 nGy h(-1). The average contribution of each of the examined radionuclides (238U, 232Th and 40K) to the total gamma dose rate was found to be equal to 12 +/- 4% for 238U, 58 +/- 6% for 232Th and 29 +/- 7% for 40K, respectively. PMID:15728423

  6. Determination of uranium and thorium isotope ratios by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Measurements conditions were selected and a procedure was proposed for determining the 234U/238U and 230Th/232Th isotope ratios using an ELEMENT single-channel double-focusing inductively coupled plasma mass spectrometer. The procedure was tested in analyzing bottom sediments from Lake Baikal with the extraction preconcentration of uranium and thorium. The accuracy of the procedure was verified using certified reference materials and a model solution by comparing the results obtained with the data of α spectrometry

  7. Contents of radionuclides and heavy metals in fish roe of commercial fish of the Zaporizhya reservoir

    International Nuclear Information System (INIS)

    Comprehensive radiation-toxicological studies of fish roe of some commercial fish of the Zaporizhya Reservoir were conducted. It was found that the greatest number of 137Cs (4,5 Bq/kg) and 90Sr (3,2 Bq/kg) was accumulated by fish roe of perch. Heavy metals (cadmium, copper, zinc and lead), and natural radionuclides 226Ra and 232Th were accumulated to a greater amount of bream fish roe

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

    International Nuclear Information System (INIS)

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

  9. Histological type of Thorotrast-induced liver tumors associated with the translocation of deposited radionuclides

    International Nuclear Information System (INIS)

    Exposure to internally deposited radionuclides is known to induce malignant tumors of various histological types. Thorotrast, a colloidal suspension of radioactive Thorium dioxide (232ThO2) that emits alpha-particles, was used as a radiographic contrast during World War II. Thorotrast is known to induce liver tumors, particularly intrahepatic cholangiocarcinoma (ICC) and angiosarcoma (AS), decades after injection. Therefore, patients injected with Thorotrast comprise a suitable study group to understand biological effects of internal ionizing radiation injury. Autoradiography and X-ray fluorescence spectrometry (XRF) were carried out on non-tumorous liver sections from Thorotrast-induced ICC (T-ICC) and Thorotrast-induced AS (T-AS). Autoradiography revealed that the slope of the regression line of the number of alpha tracks for the amount of deposited Thorium (232Th) was higher in non-tumorous parts of the liver with T-ICC than those with T-AS. XRF showed that the intensity ratio of Radium (Ra) to Thorium (Th) in non-tumorous liver tissue with T-ICC was significantly higher than that with T-AS. Furthermore, the mean 228Ra/232Th radioactivity ratio at the time of death calculated was also significantly higher in T-ICC cases than in T-AS cases. These suggest that the metabolic behavior of radionuclides such as relocation and excretion, as well as the content of deposited radionuclides, is a major factor in determining the histological type of Thorotrast-induced liver tumors. (author)

  10. 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)

  11. 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. PMID:26942842

  12. Study on the primordial concentration of radionuclides in the soil samples of Pachamali Hills,Tiruchirappalli district,Tamil Nadu

    International Nuclear Information System (INIS)

    Every living organism on this planet is constantly exposed to naturally occurring ionizing radiations, which are referred to as background radiation or natural radiation. Exposure of this ionizing radiation due to naturally occurring radionuclides present in soil and rocks is unavoidable. 238U, 232Th and 40K are the major radionuclides present abundantly in nature. These radionuclides vary in concentration over different areas due topographical, geographical, geochemical conditions of the areas concerned. Present study has been undertaken with the aim to generate baseline data on the radiation profile on the background radiation of Pachamalai Hill environment located in Tiruchirappalli dist. Totally 60 soil samples have been collected from six major sampling stations and processed and analysed using NaI(TI) gamma ray spectrometer. The activity of 232Th has been found to be varied from 23.12 to 103.4 Bqkg-1. The activity of 238U has been found to be varied form 10.64 to 47.25 Bqkg-1 and the activity of 40K varies from 120 to 324.12 Bqkg-1. The depth profile study also has been carried out. In the case of depth profile study concentration of 238U and 232Th has been found to decrease with depth in soil. However, the activity due to 40K remains more or less uniform. The mean absorbed dose rate due to primordial radionuclides is found to be 59.7 nGy h-1. (author)

  13. 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.

  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. Histological type of Thorotrast-induced liver tumors associated with the translocation of deposited radionuclides.

    Science.gov (United States)

    Yamamoto, Yoichiro; Chikawa, Junichi; Uegaki, Yoshinobu; Usuda, Nobuteru; Kuwahara, Yoshikazu; Fukumoto, Manabu

    2010-02-01

    Exposure to internally deposited radionuclides is known to induce malignant tumors of various histological types. Thorotrast, a colloidal suspension of radioactive Thorium dioxide ((232)ThO(2)) that emits alpha-particles, was used as a radiographic contrast during World War II. Thorotrast is known to induce liver tumors, particularly intrahepatic cholangiocarcinoma (ICC) and angiosarcoma (AS), decades after injection. Therefore, patients injected with Thorotrast comprise a suitable study group to understand biological effects of internal ionizing radiation injury. Autoradiography and X-ray fluorescence spectrometry (XRF) were carried out on non-tumorous liver sections from Thorotrast-induced ICC (T-ICC) and Thorotrast-induced AS (T-AS). Autoradiography revealed that the slope of the regression line of the number of alpha tracks for the amount of deposited Thorium ((232)Th) was higher in non-tumorous parts of the liver with T-ICC than those with T-AS. XRF showed that the intensity ratio of Radium (Ra) to Thorium (Th) in non-tumorous liver tissue with T-ICC was significantly higher than that with T-AS. Furthermore, the mean (228)Ra/(232)Th radioactivity ratio at the time of death calculated was also significantly higher in T-ICC cases than in T-AS cases. These suggest that the metabolic behavior of radionuclides such as relocation and excretion, as well as the content of deposited radionuclides, is a major factor in determining the histological type of Thorotrast-induced liver tumors. PMID:19917057

  16. Gamma hazards and risk associated with NORM in sediment from amang processing recycling ponds

    International Nuclear Information System (INIS)

    Amang processing is an important downstream activity of tin mining noted for technologically enhancing naturally occurring radioactive materials. A study was carried out to determine the gamma radiation hazards associated with amang processing with special reference to the sediment accumulated in amang processing ponds. Twenty eight sediment samples from two amang processing plants employing the recycling close water management system were collected and analyzed. The activity concentrations of 226Ra, 232Th and 40K in sediments were measured using gamma spectrometry analysis, with a Hyper Pure Ge-Li detector coupled to a Multi Channel Analyzer detector system. The range of mean activity concentrations of 226Ra, 232Th and 40K were between 40.94 - 189.58 Bq kg-1, 104.90 - 516.17 Bq kg-1 and 74.8-848.0 Bq/ kg respectively. The maximum activity concentrations of 226Ra, 232Th and 40K recorded were higher than Malaysia average and the worlds natural highest. Gamma Radiation Representative Level Index, Iγr associated with these levels of activity concentrations of radionuclide in sediments, warrants an immediate attention from the regulatory authorities. The contribution of amang processing and the use of recycling close water management system in enhancing potential environmental radiological risk are discussed. (author)

  17. 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.

  18. Radioactivity levels in soil of salt field area, Kelambakkam, Tamilnadu, India

    Institute of Scientific and Technical Information of China (English)

    R.RAVISANKAR; A.RAJALAKSHMI; P.ESWARAN; V GAJENDIRAN; V.MEENAKSHISUNDRAM

    2007-01-01

    Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer.The activity concentration for 232 Th,238 U and 40 K are ranged from 27.88 to 45.27 Bq/kg,from BDL to 13.30 Bq/kg,and from 135.54 to 381.28 Bq/kg,respectively.The measured activity concentrations for these radionudides were compared with world average activity of soil.The average activity concentration of 232Th in the present study is 1.19 times higher than world median value while the activity of 238 U and 40K is found to be lower.The absorbed dose rates due to these radionuclides、were calculated.The average absorbed gamma dose rate due to the presence of 232Th,238U and 40K in soil samples is 36.99 nGy-h(-1).These results indicate no radiological anomaly.The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.

  19. 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. PMID:26999725

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Thorium s-wave neutron widths from 21 to 2006 eV

    International Nuclear Information System (INIS)

    A 232Th total cross section measurement in the resolved resonance region has been requested with a 2% accuracy in order to obtain resonance parameters with a 5% accuracy. These data are required for both fast and light-water breeder reactor studies. Inspection of the prior 232Th differential data base shows several problems: the thermal cross sections seem inconsistent; the measured capture widths have large uncertanties; the two rather complete sets of measured neutron widths are systematically discrepant; and the differential data appear to give Cd capture ratios and shielded-capture resonance integrals smaller than those required by integral measurements. In order to improve the differential data base we have measured neutron transmission spectra through eight samples of 232Th. Resonance parameters have been obtained from these data using the computer code S10B. Fits to these data up to 440 eV, which concentrated on the capture widths, have been previously reported. The results of extending these fits to 2.0 keV are reported and discussed in terms of the s-wave strength function and the dilute-capture resonance integral

  5. 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.

  6. 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).

  7. Thematic network on the analysis of thorium and its isotopes in workplace materials

    International Nuclear Information System (INIS)

    An EC-funded thematic network was established to bring together experts in the field of thorium analysis in order to co-ordinate research activity and identify best analytical practice, requirements for reference materials, etc. The work programme of the network included (i) a survey of past, current and proposed research to determine future research needs; (ii) a series of intercomparison exercises to test the performance of methods for measuring thorium in workplace materials; and (iii) a workshop to promote best practice and transfer information to regulatory authorities and industry. Three interlaboratory comparisons were carried out, as planned, to test the performance of techniques and methodologies available for measurement of thorium. Test solutions containing 232Th and 228Th in equilibrium, test solutions containing 232Th and 228Th in disequilibrium and solid test samples containing 232Th and 228Th in equilibrium were supplied to participants. These were analysed by a variety of techniques. Full details of the three laboratory intercomparisons are given in a series of HSL reports and in other publications

  8. 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.

  9. 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 ...

  10. Radioactivity measurements in moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis) samples collected from Marmara region of Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Belivermis, Murat, E-mail: belmurat@istanbul.edu.t [Istanbul University, Faculty of Science, Department of Biology, 34134 Vezneciler, Istanbul (Turkey); Cotuk, Yavuz, E-mail: cotukyav@istanbul.edu.t [Istanbul University, Faculty of Science, Department of Biology, 34134 Vezneciler, Istanbul (Turkey)

    2010-11-15

    The present study was conducted to compare the {sup 137}Cs, {sup 40}K, {sup 232}Th, and {sup 238}U activity concentrations in epigeic moss (Hypnum cupressiforme) and lichen (Cladonia rangiformis). The activity levels in 37 moss and 38 lichen samples collected from the Marmara region of Turkey were measured using a gamma spectrometer equipped with a high purity germanium (HPGe) detector. The activity concentrations of {sup 137}Cs, {sup 40}K, {sup 232}Th, and {sup 238}U in the moss samples were found to be in the range of 0.36-8.13, 17.1-181.1, 1.51-6.17, and 0.87-6.70 Bq kg{sup -1} respectively, while these values were below detection limit (BDL)-4.32, 16.6-240.0, 1.32-6.47, and BDL-3.57 Bq kg{sup -1} respectively in lichen. The average moss/lichen activity ratios of {sup 137}Cs, {sup 40}K, {sup 232}Th, and {sup 238}U were found to be 1.32 {+-} 0.57, 2.79 {+-} 1.67, 2.11 {+-} 0.82, and 2.19 {+-} 1.02, respectively. Very low {sup 137}Cs concentrations were observed in moss and lichen samples compared to soil samples collected from the same locations in a previous study. Seasonal variations of the measured radionuclide activities were also examined in the three sampling stations.

  11. 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)

  12. Investigation and analysis of NORM source term in the phosphate industry based on the first nationwide pollution source survey

    International Nuclear Information System (INIS)

    China has launched the First Nationwide Pollution Source Survey (FNPSS) during 2006-2009. Ministry Environmental Protection (MEP) sponsored the campaign of measuring the natural radionuclide contents in all factories and mines nationwide in relation to phosphate, rare-earth, niobium/tantalum, zircon, tin, lead/zinc, copper, iron, coal, aluminum and vanadium. This paper analyzes mainly the data on the contents of U, 232Th and 226Ra in phosphate ore and solid waste produced by the phosphate industry in China, as one of a series of papers on naturally occurring radioactive materials (NORMs) investigation. It is concluded that the averages of U, 232Th and 226Ra in phosphate ore are 396 Bq/kg, 26 Bq/kg and 403.6 Bq/kg, respectively. The average of U and 226Ra contents in solid waste produced by the phosphate industry are both less than 200 Bq/kg, mostly. The range of U and 226Ra are 22.7-723.6 Bq/kg and 5.6-1042.1 Bq/kg, respectively. The 232Th content is very low. It is suggested that the phosphate industrial solid waste should be subject to sort management, and some phosphate industry factories and mines should carry out relevant investigation, radiation evaluation and research. (authors)

  13. Natural radioactivity levels in river, stream and drinking water of the northwestern areas of Pakistan

    International Nuclear Information System (INIS)

    Natural radioactivity in the aquatic media has been determined by collecting samples of river, stream and drinking water from the northwestern areas of Pakistan. The concentrations of 40K, 226Ra and 232Th have been measured using a low background gamma-spectrometer and a 10 cm3 planar intrinsic high purity germanium detector. The annual ingestion of these radionuclides, using local consumption rates (average over the whole population) of 0.9 l x d-1, were estimated to be 49.2, 6.2 and 1.1 Bq x y-1 for 40K, 226Ra and 232Th, respectively. A comparison of the annual intakes of these radionuclides, using annual consumption rates of NCRP, ICRP and FBSP shows that the contribution from natural radionuclides to annual intake is slightly greater for NCRP than for ICRP and FBSP consumption rates. However, the estimated values and weighted means of these radionuclides compare well with the world average. The annual effective dose equivalent from drinking water was found to be 3.6 x 10-6 mSv x y-1 (226Ra), 3.2 x 10-12 mSv x y-1 (232Th) and 2.1 x 10-6 mSv x y-1 (40K). These values are lower than those given by NCRP. (author)

  14. Radiological Assessment of Drinking Water of the Chittagong Region of Bangladesh

    International Nuclear Information System (INIS)

    The specific activity of 222Rn, 226Ra, 232Th and 40K in drinking water of the Chittagong region of Bangladesh was measured using high resolution γ spectrometry. The specific activity of 222Rn in the drinking water ranged from 2.04 ± 0.51 to 9.39 ± 2.06 Bq.1-1 and the mean activity was 4.46 ± 1.95 Bq.1-1. The mean specific activity of 226Ra was found to be 0.043 ± 0.017 Bq.1-1, the mean activity of 232Th was 0.19 ± 0.05 Bq.1-1, and the mean 40K activity was 4.16 ± 1.58 Bq.1-1. No 134Cs and 137Cs activity was detected in any of the samples of drinking water from the region. From these data the age-dependent associated effective doses due to the ingestion of these isotopes as a consequence of direct consumption of drinking water has been calculated. The average adult effective dose due to intake of drinking water was 56.2 μSv.y-1 for 232Th, 7.6 μSv.y-1 for 226Ra and 16.7 μSv.y-1 for 40K. (author)

  15. 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.

  16. Radioactivity in raw materials and end products in the Italian ceramics industry

    International Nuclear Information System (INIS)

    The natural radioactivity due to the presence of 238U, 232Th and 40K in zirconium minerals (zircon and baddeleyite) used in the Italian ceramics industry, in tiles and in waste sludges resulting from ceramic processes, has been measured. The measurements were made by γ-ray spectrometry with a high-purity germanium (HPGe) detector connected to a multichannel analyser. The average concentrations of 238U and 232Th observed in the mineral samples (>3000 and >500 Bq kg-1, respectively) are higher than the concentrations found in the earth's crust by one or two orders of magnitude. The specific activities of tiles and sludges are much lower than in zirconium minerals. The 238U and 232Th concentrations in tiles (50-79 and 52-66 Bq kg-1, respectively) are not higher than in other building materials. The 238U concentration of sludges (116-193 Bq kg-1) is 4-6 times higher than the mean value for the earth's crust. The results are examined on the basis of the existing Italian legislation (D.Lgs no. 230, 1995, Gazzetta Ufficiale 13/06/1996, no. 136, Supplemento Ordinario, Rome, Italy) and the EC Directive no. 29/Euratom of the year 1996 (Gazzetta Ufficiale della Communita Europea 29/06/1996, no. L159)

  17. Assessment of Natural Radioactivity Level in Groundwater from Selected Areas in Accra Metropolis

    Directory of Open Access Journals (Sweden)

    E.J.M. Nguelem

    2013-02-01

    Full Text Available The aim of this present study was to assess natural radioactivity levels in selected groundwater (boreholes and wells used as domestic purposes in particular and drinking as well in some communities in Adentan and Abokobi areas in Greater Accra region of Ghana. This was achieved by first measuring the activity concentration of 222Rn, 40K and 232 232Th in groundwater samples using High-Purity Germanium (HPGe detector. These concentrations of 40K, 222Rn and 232Th were used with their ingested dose conversion factors to estimate annual effective dose for Adult members of public due to consumption of the groundwater. The estimated average annual effective dose due to consumption of 40K, 222Rn and 232Th in the water samples from Adentan and Abokobi were 113.007±3.940 and 76.568±2.321 μSv/y, respectively. These were compared with the estimated average annual dose due to ingestion of nuclides in water by the WHO (100 μSv/y and the estimated average dose due to ingestion of radionuclides in food and water (290 μSv/y by UNSCEAR (2000. They are found within the range even though Adentan value is slightly higher than the WHO average value. The results show that consumption of groundwater may not pose any radiological health hazard to the public.

  18. Activity concentrations of natural radionuclide levels in well waters of Ago Iwoye, Nigeria

    International Nuclear Information System (INIS)

    Natural Radioactivity, though natural requires concentration monitoring, especially for the health/ environmental checks of the populace. Materials and Methods; The activity concentrations of 40K, 238U and 232Th in the waters from wells with depths ranging between 141.0 214.0 feet were randomly sampled and determined from 20 locations in Ago-Iwoye town in South Western, Nigeria. Results: The activity concentrations obtained were in the ranges of (9.9-50.9)Bq/kg with mean value of (25.1±10.7) Bq/kg for 40K, (BDL-15.0) Bq/kg with mean value of (1.2±3.2) Bq/kg for 238U and (BDL-6.2) Bq/kg with mean value of (1.6±1.7) Bq/kg for 232Th. Conclusion: According to the results obtained for the activity concentrations from 20 well water samples in Ago Iwoye, Southwestern, Nigeria it was observed that the V40K, 238U and 232Th values were still within the tolerance level indicating minimal radiological health burden on the human populace and the environment.

  19. Concentration and activity ratio of thorium isotopes in surface soil around proposed uranium mining site in India

    International Nuclear Information System (INIS)

    Unconformity type of uranium deposits at Lambapur and Peddagattu located in Nalgonda District of Andhra Pradesh, India has been reported. Soil surveillance for isotopic thorium belonging to two different radioactive decay chains provide information on characterization of soil formation due to weathering of underlying host rocks. Thorium concentration and their isotopic activity ratio in localized soil samples were assessed. Thorium concentration and 230Th/232Th activity ratio were observed to be in the range of 15 ±3 mg/kg to 132 ± 15 mg/kg and 0.21± 0.07-0.68 ± 0.05, respectively. A significant wide variation in thorium concentration and that of activity ratio for localized area soil indicates the soil development due to a different type of underlying host rocks. Activity ratio of 228Th/232Th in the soil samples of the study area are observed to vary from 0.87 ± 0.05 to 1.07 ± 0.15 with a mean of 0.96 ± 0.02, indicating secular equilibrium between 232Th and its daughter product 228Th. The study describes the application of isotopic thorium activity as a chronological indicator for geological characterization. (author)

  20. Study of environmental natural gamma radiation dose and activity of uranium-238, thorium-232 using NaI (Tl) scintillation detector

    International Nuclear Information System (INIS)

    Exposure to ionizing radiation from natural sources is a continuous and unavoidable feature of life-systems on the earth. The environmental effective gamma radiation dose from terrestrial and cosmic radiation at height one foot above the earth's surface in open atmosphere has been measured at twenty different places in Sindhudurg district of Maharashtra state by using 2x2 NaI (Tl) scintillation detector. The activity of 238U and 232Th has been measured using gamma ray spectroscopy. The effective gamma radiation dose at different locations varies between, 0.286 to 0.804 mS/y, with an average value 0.512 mSv/y. The 238U activity varies from 0.466 KBq/m2 to 1.133 KBq/m2 with mean value of 0.684 KBq/m2. The 232Th activity varies from 0.552 KBq/m2 to 1.267 KBq/m2 with mean 0.8682 KBq/m2. The 238U to 232Th activity ratio varies from 0.494 to 1.47 with mean 0.898. (author)