WorldWideScience

Sample records for 240pu isotope activities

  1. Plutonium isotopes 238Pu, 239+240Pu, 241Pu and 240Pu/239Pu atomic ratios in the southern Baltic Sea ecosystem

    Dagmara I. Strumińska-Parulska

    2010-09-01

    Full Text Available The paper summarizes the results of plutonium findings in atmospheric fallout samples and marine samples from the southern Baltic Sea during our research in 1986-2007. The activities of 238Pu and 239+240Pu isotopes were measured with an alpha spectrometer. The activities of 241Pu were calculated indirectly by 241Am activity measurements 16-18 years after the Chernobyl accident. The 240Pu/239Pu atomic ratios were measured using accelerator mass spectrometry (AMS. The 241Pu activities indicate that the main impact of the Chernobyl accident was on the plutonium concentration in the components of the Baltic Sea ecosystem examined in this work. The highest 241Pu/239+240Pu activity ratio was found in sea water (140 ± 33. The AMS measurements of atmospheric fallout samples collected during 1986 showed a significant increase in the 240Pu/239Pu atomic ratio from 0.29 ± 0.04 in March 1986 to 0.47 ± 0.02 in April 1986.

  2. Determination of 240Pu/239Pu isotope ratios in Kara Sea and Novaya Zemlya sediments using accelerator mass spectrometry

    Accelerator mass spectrometry (AMS) has been used to determine Pu activity concentrations and 240Pu/239Pu isotope ratios in sediments from the Kara Sea and radioactive waste dumping sites at Novaya Zemlya. Measured 239,240Pu activities ranged from 0.06 - 9.8 Bq/kg dry weight, 240Pu/239Pu atom ratios ranged from 0.13 to 0.28, and 238Pu/239,240Pu activity ratios from 0.02 to 0.6. Perturbations from global fallout isotope ratios were evident at three sites: the Yenisey Estuary and Abrosimov Fjords where 240Pu/239Pu ratios were lower (0.13-0.14); and Stepovogo Fjord sediments where ratios were higher (up to 0.28) than fallout ratios. Based on procedural blanks, detection limits for AMS were below 1 fg Pu and the method showed good precision for isotope ratio measurements, minimal matrix, interference and memory effects. For high level samples, comparison between alpha spectrometry and AMS gave good agreement for measurement of 239,240Pu activity concentrations. (author)

  3. Modeling and production of 240Am by deuteron-induced activation of a 240Pu target

    Finn, Erin C.; McNamara, Bruce K.; Greenwood, Lawrence R.; Wittman, Richard S.; Soderquist, Chuck Z.; Woods, Vincent T.; VanDevender, Brent A.; Metz, Lori A.; Friese, Judah I.

    2015-02-01

    A novel reaction pathway for production of 240Am is reported. Models of reaction cross-sections in EMPIRE II suggests that deuteron-induced activation of a 240Pu target produces maximum yields of 240Am from 11.5 MeV incident deuterons. This activation had not been previously reported in the literature. A 240Pu target was activated under the modeled optimum conditions to produce 240Am. The modeled cross-section for the 240Pu(d, 2n)240Am reaction is on the order of 20-30 mbarn, but the experimentally estimated value is 5.3 ± 0.2 mbarn. We discuss reasons for the discrepancy as well as production of other Am isotopes that contaminate the final product.

  4. Modeling and production of 240Am by deuteron-induced activation of a 240Pu target

    A novel reaction pathway for production of 240Am is reported. Models of reaction cross-sections in EMPIRE II suggest that deuteron-induced activation of a 240Pu target produces maximum yields of 240Am from 11.5 MeV incident deuterons. This activation had not been previously reported in the literature. A 240Pu target was activated under the modeled optimum conditions to produce 240Am. The modeled cross-section for the 240Pu(d, 2n)240Am reaction is on the order of 20–30 mbarn, but the experimentally estimated value is 5.6 ± 0.2 mbarn. We discuss reasons for the discrepancy as well as production of other Am isotopes that contaminate the final product

  5. Modeling and production of {sup 240}Am by deuteron-induced activation of a {sup 240}Pu target

    Finn, Erin C., E-mail: Erin.Finn@pnnl.gov; McNamara, Bruce, E-mail: Bruce.McNamara@pnnl.gov; Greenwood, Larry, E-mail: Larry.Greenwood@pnnl.gov; Wittman, Richard, E-mail: Richard.Wittman@pnnl.gov; Soderquist, Charles, E-mail: Chuck.Soderquist@pnnl.gov; Woods, Vincent, E-mail: Vincent.Woods@pnnl.gov; VanDevender, Brent, E-mail: Brent.Vandevender@pnnl.gov; Metz, Lori, E-mail: Lori.Metz@pnnl.gov; Friese, Judah, E-mail: Judah.Friese@pnnl.gov

    2015-04-15

    A novel reaction pathway for production of {sup 240}Am is reported. Models of reaction cross-sections in EMPIRE II suggest that deuteron-induced activation of a {sup 240}Pu target produces maximum yields of {sup 240}Am from 11.5 MeV incident deuterons. This activation had not been previously reported in the literature. A {sup 240}Pu target was activated under the modeled optimum conditions to produce {sup 240}Am. The modeled cross-section for the {sup 240}Pu(d, 2n){sup 240}Am reaction is on the order of 20–30 mbarn, but the experimentally estimated value is 5.6 ± 0.2 mbarn. We discuss reasons for the discrepancy as well as production of other Am isotopes that contaminate the final product.

  6. Presence of plutonium isotopes, {sup 239}Pu and {sup 240}Pu, in soils from Chile

    Chamizo, E., E-mail: echamizo@us.es [Centro Nacional de Aceleradores, Avda. Thomas Alba Edison, 7, 41092 Sevilla (Spain); Garcia-Leon, M., E-mail: manugar@us.es [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Avda. Reina Mercedes sn, 41012 Seville (Spain); Peruchena, J.I., E-mail: jiperuchena@gmail.com [Centro Nacional de Aceleradores, Avda. Thomas Alba Edison, 7, 41092 Sevilla (Spain); Cereceda, F., E-mail: francisco.cereceda@usm.cl [Laboratorio de Quimica Ambiental, Centro de Tecnologias Ambientales (CETAM), Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Vidal, V., E-mail: victor.vidal@usm.cl [Laboratorio de Quimica Ambiental, Centro de Tecnologias Ambientales (CETAM), Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Pinilla, E., E-mail: epinilla@unex.es [Departamento de Quimica Analitica, Facultad de Ciencias, Universidad de Extremadura, Avda. de Elvas sn, 06071 Badajoz (Spain); Miro, C., E-mail: cmiro@unex.es [Departamento de Fisica Aplicada, Universidad de Extremadura, Avda. de la Universidad sn, 10071 Caceres (Spain)

    2011-12-15

    Plutonium is present in every environmental compartment, due to a variety of nuclear activities. The Southern Hemisphere has received about 20% of the global {sup 239}Pu and {sup 240}Pu environmental inventory, with an important contribution of the so-called tropospheric fallout from both the atmospheric nuclear tests performed in the French Polynesia and in Australia by France and United Kingdom, respectively. In this work we provide new data on the impact of these tests to South America through the study of {sup 239}Pu and {sup 240}Pu in soils from different areas of Northern, Central and Southern Chile. The obtained results point out to the presence of debris from the French tests in the 20-40 Degree-Sign Southern latitude range, with {sup 240}Pu/{sup 239}Pu atomic ratios quite heterogeneous and ranging from 0.02 to 0.23. They are significantly different from the expected one for the global fallout in the Southern Hemisphere for the 30-53 Degree-Sign S latitude range (0.185 {+-} 0.047), but they follow the same trend as the reported values by the Department of Energy of United States for other points with similar latitudes. The {sup 239+240}Pu activity inventories show as well a wider variability range in that latitude range, in agreement with the expected heterogeneity of the contamination.

  7. Presence of plutonium isotopes, 239Pu and 240Pu, in soils from Chile

    Plutonium is present in every environmental compartment, due to a variety of nuclear activities. The Southern Hemisphere has received about 20% of the global 239Pu and 240Pu environmental inventory, with an important contribution of the so-called tropospheric fallout from both the atmospheric nuclear tests performed in the French Polynesia and in Australia by France and United Kingdom, respectively. In this work we provide new data on the impact of these tests to South America through the study of 239Pu and 240Pu in soils from different areas of Northern, Central and Southern Chile. The obtained results point out to the presence of debris from the French tests in the 20–40° Southern latitude range, with 240Pu/239Pu atomic ratios quite heterogeneous and ranging from 0.02 to 0.23. They are significantly different from the expected one for the global fallout in the Southern Hemisphere for the 30–53°S latitude range (0.185 ± 0.047), but they follow the same trend as the reported values by the Department of Energy of United States for other points with similar latitudes. The 239+240Pu activity inventories show as well a wider variability range in that latitude range, in agreement with the expected heterogeneity of the contamination.

  8. Isotope ratios of 240Pu/239Pu in soil samples from different areas

    Plutonium concentrations and 240Pu/239Pu atom ratios in soil samples from Japan and other areas in the world (including IAEA standard reference materials) were determined by ICP-MS. The range of 240Pu/239Pu atom ratios observed in 21 Japanese soil samples was 0.155 - 0.194 and the average was 0.180 ± 0.011, which is comparable to the global fallout value. A low ratio of about 0.05, which is derived from Pu-bomb, was found in samples from Nishiyama (Nagasaki) and Mururoa Atoll (IAEA-368), while a high ratio of about 0.31 was found in a sample from Bikini Atoll (Marshall Islands). The ratio for Irish Sea sediment (IAEA-135) was 0.21, which was higher than the global fallout value, suggesting the influence by the contamination from the Sellafield facility. The 240Pu/239Pu atom ratios in soils from the Chernobyl area were determined, and the ratio was found to be very high (about 0.4), indicating the high burn-up grade of the reactor fuel. These results show that the 240Pu/239Pu ratio can be used as a finger print to identify the source of the contamination. (author)

  9. 238Pu and 239+240Pu activities in lower Rhone valley in cultivated soils

    Measured 238Pu and 239+240Pu activities in French soils can be explained by the fallout from atmospheric nuclear tests and the disintegration of a US nuclear reactor satellite in 1964. However, some soil samples from the lower Rhone valley show higher mass activities, due to the Marcoule nuclear fuel reprocessing plant discharges. Soil samples from the Camargue, flooded in 1993 and 1994, where Rhone River sediments have been deposited, contain Pu from liquid effluents released by the nuclear plant. Seven samples taken near the nuclear facility show a direct influence by its atmospheric releases. Samples from soils irrigated with Rhone River water for 30 years do not show any activity significantly higher than regional means. (authors)

  10. Study of neutron-deficient isotopes of Fl in the 239Pu, 240Pu + 48Ca reactions

    Voinov, A. A.; Utyonkov, V. K.; Brewer, N. T.; Oganessian, Yu Ts; Rykaczewski, K. P.; Abdullin, F. Sh; Dmitriev, S. N.; Grzywacz, R. K.; Itkis, M. G.; Miernik, K.; Polyakov, A. N.; Roberto, J. B.; Sagaidak, R. N.; Shirokovsky, I. V.; Shumeiko, M. V.; Tsyganov, Yu S.; Subbotin, V. G.; Sukhov, A. M.; Sabelnikov, A. V.; Vostokin, G. K.; Hamilton, J. H.; Stoyer, M. A.; Strauss, S. Y.

    2016-07-01

    The results of the experiments aimed at the synthesis of Fl isotopes in the 239Pu + 48Ca and 240Pu + 48Ca reactions are presented. The experiment was performed using the Dubna gas-filled recoil separator at the U400 cyclotron. In the 239Pu+48Ca experiment one decay of spontaneously fissioning 284Fl was detected at 245-MeV beam energy. In the 240Pu+48Ca experiment three decay chains of 285Fl were detected at 245 MeV and four decays were assigned to 284Fl at the higher 48Ca beam energy of 250 MeV. The α-decay energy of 285Fl was measured for the first time and decay properties of its descendants 281Cn, 277Ds, 273Hs, 269Sg, and 265Rf were determined more precisely. The cross section of the 239Pu(48Ca,3n)284Fl reaction was observed to be about 20 times lower than those predicted by theoretical models and 50 times less than the value measured in the 244Pu+48Ca reaction. The cross sections of the 240Pu(48Ca,4-3n)284,285Fl at both 48Ca energies are similar and exceed that observed in the reaction with lighter isotope 239Pu by a factor of 10. The decay properties of the synthesized nuclei and their production cross sections indicate rapid decrease of stability of superheavy nuclei with departing from the neutron number N=184 predicted to be the next magic number.

  11. Determination of the 240Pu/239Pu atom ratio in low activity environmental samples by alpha spectrometry and spectral deconvolution

    In this paper, a simple technique, based on commercially-available software developed for gamma spectra analysis (MicroSAMPO trademark), is described by which this complex multiplet can be resolved at the much lower activities typical of many environmental samples. In our approach, it is not necessary to make any alterations to the normal alpha spectrometric set-up (including energy dispersion), other than to improve collimation. The instrumental function is defined for each spectrum by fitting a modified gaussian with exponential tails to the comparatively well-resolved 242Pu ''doublet'' (used as tracer) and, if present, the 238Pu ''doublet''. The fitted peaks are used to create an energy calibration file with which, using published energy data, the positions (in channels) of the component peaks of the multiplet are predicted. These positions are not altered subsequently when MicroSAMPO's interactive multiplet analysis facility is used to quantify the relative spectral intensities of the components. Before calculating the 240Pu/239Pu ratio, it is advisable to correct for coincidence summing of alpha particles and conversion electrons. The technique has been applied to the determination of the 240Pu/239Pu ratio in a set of environmental samples, most of which were supplied by IAEA-MEL under their laboratory intercomparison programme. Subsequently, replicate samples were analysed independently using thermal ionisation mass spectrometry. The agreement between the two sets of data was most satisfactory. Further validation of this deconvolution technique was provided by the good agreement between the measured alpha-emission probabilities for the component peaks in the 239,240Pu multiplet and published values. (orig.)

  12. Separation and activity determination of 239+240Pu, 241Am and Curium (242and244Cm) in evaporator concentrate by Alpha Spectrometry

    Alpha spectrometry analysis was used for activity determinations of Pu, Am and Cm isotopes in evaporator concentrate samples from nuclear power plants. Using a sequential procedure the first step was Pu isolation by an anion exchange column followed by an Am and Cm separation of U and Fe by a co-precipitation with oxalic acid. The precipitate was used for americium and curium separation of strontium by using a TRU resin extraction chromatography column. Due to their chemical similarities and energy difference it was seen that the simultaneous determination of 241Am, 242Cm and 243,244Cm isotopes is possible using the 243Am as tracer, once they have peaks in different region of interest (ROI) in the alpha spectrum. In this work it was used tracers, 238Pu, 243Am, 244Cm and 232U, for determination and quantification of theirs isotopes, respectively. The standard deviations for replicate analysis were calculated and for 241Am it was (1,040 ± 160 mBqKg-1), relative standard deviation 15.38%, and for 239+240Pu it was (551 +- 44 mBqKg-1), relative standard deviation 7.98%. In addition, for the 242Cm isotope the standard deviation for determinations was(75 ± 23 mBqKg-1), with the relative standard deviation 30.67% higher than for 241Am and 239+240Pu. The radiometric yields ranged from 90% to 105% and the lower limit of detection was estimated as being 2.05 mBqKg-1. (author)

  13. Simultaneous determination of radiocesium ((135)Cs, (137)Cs) and plutonium ((239)Pu, (240)Pu) isotopes in river suspended particles by ICP-MS/MS and SF-ICP-MS.

    Cao, Liguo; Zheng, Jian; Tsukada, Hirofumi; Pan, Shaoming; Wang, Zhongtang; Tagami, Keiko; Uchida, Shigeo

    2016-10-01

    Due to radioisotope releases in the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, long-term monitoring of radiocesium ((135)Cs and (137)Cs) and Pu isotopes ((239)Pu and (240)Pu) in river suspended particles is necessary to study the transport and fate of these long-lived radioisotopes in the land-ocean system. However, it is expensive and technically difficult to collect samples of suspended particles from river and ocean. Thus, simultaneous determination of multi-radionuclides remains as a challenging topic. In this study, for the first time, we report an analytical method for simultaneous determination of radiocesium and Pu isotopes in suspended particles with small sample size (1-2g). Radiocesium and Pu were sequentially pre-concentrated using ammonium molybdophosphate and ferric hydroxide co-precipitation, respectively. After the two-stage ion-exchange chromatography separation from the matrix elements, radiocesium and Pu isotopes were finally determined by ICP-MS/MS and SF-ICP-MS, respectively. The interfering elements of U ((238)U(1)H(+) and (238)U(2)H(+) for (239)Pu and (240)Pu, respectively) and Ba ((135)Ba(+) and (137)Ba(+) for (135)Cs and (137)Cs, respectively) were sufficiently removed with the decontamination factors of 1-8×10(6) and 1×10(4), respectively, with the developed method. Soil reference materials were utilized for method validation, and the obtained (135)Cs/(137)Cs and (240)Pu/(239)Pu atom ratios, and (239+240)Pu activities showed a good agreement with the certified/information values. In addition, the developed method was applied to analyze radiocesium and Pu in the suspended particles of land water samples collected from Fukushima Prefecture after the FDNPP accident. The (135)Cs/(137)Cs atom ratios (0.329-0.391) and (137)Cs activities (23.4-152Bq/g) suggested radiocesium contamination of the suspended particles mainly originated from the accident-released radioactive contaminates, while similar Pu contamination of suspended

  14. Evaluation both level and 239+240Pu spatial contamination of the Lira object and the neighbouring areas

    In the work the generalization of considerable data collection for revealing of 239+240Pu content range discriminative for Lira object and neighbouring areas is carried out. 239+240Pu mean specific activity in the soil cover surface and in the Berezovka River bottom sedimentations are determined. The correlation dependence between 239+240Pu artificial radionuclides and 137Cs is revealed. The general source of artificial radionuclide origination for examined isotopes is shown up, and it is related with global radioactive fallout

  15. Precision and accuracy in the determination of sup(238)Pu/(sup(239)Pu + sup(240)Pu) alpha activity ratio by alpha spectrometry

    Investigations were carried out for the evaluation of precision and accuracy in determining sup(238)Pu/(sup(239)Pu + sup(240)Pu) activity ratio by α spectrometry from the point of view of determining sup(238)Pu accurately in plutonium samples and in exploiting Isotope Dilution Alpha Spectrometry (IDAS) for determining the concentration of plutonium in the irradiated fuel dissolver solutions. Synthetic mixtures with α activity ratios ranging from 0.01 to 10 were prepared using sup(238)Pu and sup(239)Pu isotopes. Different methods which can be routinely used were tried to calculate the α activity ratio from the α spectrum taken on electrodeposited sources prepared from these mixtures. An accuracy of better than 0.5% and a precision of +- 0.2% (1 sigma) is demonstrated in the determination of α activity ratios ranging from 0.01 to 10 using electrodeposited sources and the evaluation method based on the geometric progression decrease (G.P.) for the far tail of the spectrum. (auth.)

  16. Determination of plutonium isotopes (238Pu, 239Pu, 240Pu, 241Pu) in environmental samples using radiochemical separation combined with radiometric and mass spectrometric measurements

    Xu, Yihong; Qiao, Jixin; Hou, Xiaolin;

    2014-01-01

    This paper reports an analytical method for the determination of plutonium isotopes (238Pu, 239Pu, 240Pu, 241Pu) in environmental samples using anion exchange chromatography in combination with extraction chromatography for chemical separation of Pu. Both radiometric methods (liquid scintillation...... counting and alpha spectrometry) and inductively coupled plasma mass spectrometry (ICP-MS) were applied for the measurement of plutonium isotopes. The decontamination factors for uranium were significantly improved up to 7.5×105 for 20 g soil compared to the level reported in the literature......, this is critical for the measurement of plutonium isotopes using mass spectrometric technique. Although the chemical yield of Pu in the entire procedure is about 55%, the analytical results of IAEA soil 6 and IAEA-367 in this work are in a good agreement with the values reported in the literature or reference...

  17. Estimation of 240Pu Mass in a Waste Tank Using Ultra-Sensitive Detection of Radioactive Xenon Isotopes from Spontaneous Fission

    We report on a technique to detect and quantify the amount of 240Pu in a large tank used to store nuclear waste from plutonium production at the Hanford nuclear site. While the contents of this waste tank are known from previous grab sample measurements, our technique could allow for determination of the amount of 240Pu in the tank without costly sample retrieval and analysis of this highly radioactive material. This technique makes an assumption, which was confirmed, that 240Pu dominates the spontaneous fissions occurring in the tank.

  18. A multi-radionuclide approach to evaluate the suitability of (239+240)Pu as soil erosion tracer.

    Meusburger, Katrin; Mabit, Lionel; Ketterer, Michael; Park, Ji-Hyung; Sandor, Tarjan; Porto, Paolo; Alewell, Christine

    2016-10-01

    Fallout radionuclides have been used successfully worldwide as tracers for soil erosion, but relatively few studies exploit the full potential of plutonium (Pu) isotopes. Hence, this study aims to explore the suitability of the plutonium isotopes (239)Pu and (240)Pu as a method to assess soil erosion magnitude by comparison to more established fallout radionuclides such as (137)Cs and (210)Pbex. As test area an erosion affected headwater catchment of the Lake Soyang (South Korea) was selected. All three fallout radionuclides confirmed high erosion rates for agricultural sites (>25tha(-1)yr(-1)). Pu isotopes further allowed determining the origin of the fallout. Both (240)Pu/(239)Pu atomic ratios and (239+240)Pu/(137)Cs activity ratios were close to the global fallout ratio. However, the depth profile of the (239+240)Pu/(137)Cs activity ratios in undisturbed sites showed lower ratios in the top soil increments, which might be due to higher migration rates of (239+240)Pu. The activity ratios further indicated preferential transport of (137)Cs from eroded sites (higher ratio compared to the global fallout) to the depositional sites (smaller ratio). As such the (239+240)Pu/(137)Cs activity ratio offered a new approach to parameterize a particle size correction factor that can be applied when both (137)Cs and (239+240)Pu have the same fallout source. Implementing this particle size correction factor in the conversion of (137)Cs inventories resulted in comparable estimates of soil loss for (137)Cs and (239+240)Pu. The comparison among the different fallout radionuclides highlights the suitability of (239+240)Pu through less preferential transport compared to (137)Cs and the possibility to gain information regarding the origin of the fallout. In conclusion, (239+240)Pu is a promising soil erosion tracer, however, since the behaviour i.e. vertical migration in the soil and lateral transport during water erosion was shown to differ from that of (137)Cs, there is a clear

  19. Fabrication of 12% {sup 240}Pu calorimetry standards

    Long, S.M.; Hildner, S.; Gutierrez, D.; Mills, C.; Garcia, W.; Gurule, C.

    1995-08-01

    Throughout the DOE complex, laboratories are performing calorimetric assays on items containing high burnup plutonium. These materials contain higher isotopic range and higher wattages than materials previously encountered in vault holdings. Currently, measurement control standards have been limited to utilizing 6% {sup 240}Pu standards. The lower isotopic and wattage value standards do not complement the measurement of the higher burnup material. Participants of the Calorimetry Exchange (CALEX) Program have identified the need for new calorimetric assay standards with a higher wattage and isotopic range. This paper describes the fabrication and verification measurements of the new CALEX standard containing 12% {sup 240}Pu oxide with a wattage of about 6 to 8 watts.

  20. Statistical activities during 1976 and the design and initial analysis of nuclear site studies. [/sup 241/Am, /sup 137/Cs, /sup 239/Pu, /sup 240/Pu

    Gilbert, R O; Essington, E H; Brady, D N; Doctor, P G; Eberhardt, L L

    1977-05-01

    Statistical design and analysis activities for the Nevada Applied Ecology Group (NAEG) during 1976 are briefly outlined. This is followed by a description of soil data collected thus far at nuclear study sites. Radionuclide concentrations in surface soil collected along a transect from ground zero (GZ) along the main fallout pattern are given for Nuclear Site (NS) 201. Concentrations in soil collected at 315 locations on a grid system at 200 foot spacings are also given for this site. The /sup 241/Am to /sup 137/Cs ratios change over NS 201 depending on location relative to GZ. They range from less than one where /sup 241/Am is at low levels, to more than fifty where /sup 241/Am levels are high (near GZ). The estimated median /sup 239/ /sup 240/Pu to /sup 241/Am ratio is 11 and appears to be relatively constant over the area (the 95 percent lower and upper limits on the true median ratio are about 8 and 14).

  1. Retrospective determination of 238Pu, 239,240Pu and 90Sr activities in the outer bark of Norway spruce (Picea abies (L.) Karst.) collected at various sites in the Czech Republic

    The activity concentrations of 238Pu, 239,240Pu and 90Sr were determined in 25 archived spruce outer bark samples collected in coniferous forests across the Czech Republic in 1995. At three sampling sites the radionuclide activity concentrations were determined in forest soil. Data was provided on the cumulative deposition and vertical distribution of 238Pu, 239,240Pu and 90Sr in forest soil. The median activity concentration of 238Pu in the spruce bark samples was 0.009 Bq kg-1. The median activity concentration of 239,240Pu was 0.212 Bq kg-1, and the median activity concentration of 90Sr was 10.6 Bq kg-1. The radionuclide activity concentration distribution was not significantly explained by the local long-term (1961-2000) mean annual precipitation totals, by site elevation, by bark acidity, by soil moisture and soil texture. The activity concentrations of the radionuclides in bark were found to be higher than or comparable with the published and measured figures for radionuclide activity concentrations in cultivated and uncultivated soils (0-20 cm layer) in the Czech Republic and abroad. The activity concentration ratio of 90Sr/239,240Pu in the investigated spruce bark samples was higher than in the relevant soil samples. We assume that the crucial radioactive contamination loads in bark occurred in the first half of the 1960s, when the concentration of the investigated radionuclides in the air was highest. Spruce trunk bark has preserved relatively high activity concentrations of these radionuclides. The mechanism governing the long-term radionuclide activity concentrations in outer bark proportional to the local radioactive fallout rates is not correctly known. Our results indicate the suitability of spruce bark for use as an effective monitor of radioactive plume fallout loads even several decades after the contamination episode. (author)

  2. Measurement of fallout radionuclides, (239)(,240)Pu and (137)Cs, in soil and creek sediment: Sydney Basin, Australia.

    Smith, B S; Child, D P; Fierro, D; Harrison, J J; Heijnis, H; Hotchkis, M A C; Johansen, M P; Marx, S; Payne, T E; Zawadzki, A

    2016-01-01

    Soil and sediment samples from the Sydney basin were measured to ascertain fallout radionuclide activity concentrations and atom ratios. Caesium-137 ((137)Cs) was measured using gamma spectroscopy, and plutonium isotopes ((239)Pu and (240)Pu) were quantified using accelerator mass spectrometry (AMS). Fallout radionuclide activity concentrations were variable ranging from 0.6 to 26.1 Bq/kg for (137)Cs and 0.02-0.52 Bq/kg for (239+240)Pu. Radionuclides in creek sediment samples were an order of magnitude lower than in soils. (137)Cs and (239+240)Pu activity concentration in soils were well correlated (r(2) = 0.80) although some deviation was observed in samples collected at higher elevations. Soil ratios of (137)Cs/(239+240)Pu (decay corrected to 1/1/2014) ranged from 11.5 to 52.1 (average = 37.0 ± 12.4) and showed more variability than previous studies. (240)Pu/(239)Pu atom ratios ranged from 0.117 to 0.165 with an average of 0.146 (±0.013) and an error weighted mean of 0.138 (±0.001). These ratios are lower than a previously reported ratio for Sydney, and lower than the global average. However, these ratios are similar to those reported for other sites within Australia that are located away from former weapons testing sites and indicate that atom ratio measurements from other parts of the world are unlikely to be applicable to the Australian context. PMID:26344369

  3. 240Pu/239Pu atom ratios in seawater from the western North Pacific and its marginal sea

    Full text: The atom ratio of 240Pu/239Pu is known to be a useful tracer to identify the sources of plutonium in the ocean. The objectives of this study are to measure the 239+240Pu activities and 240Pu/239Pu atom ratios in seawater from the western North Pacific and its marginal sea and to discuss the transport processes of plutonium. The 240Pu/239Pu atom ratios were measured with sector-field ICPMS. The atom ratios were significantly higher than the mean global fallout ratio. These high atom ratios proved the existence of close-in fallout plutonium originating from the Pacific proving grounds. (author)

  4. Seasonal variations in activity concentrations of 137Cs, 40K, 7Be, 228Ac, 99Tc, 90Sr, and 239/240Pu in Fucus vesiculosus and Ascophyllum nodosum from the South-Eastern coast of Norway

    Brown algae have been proven to be useful indicator organisms for heavy metals and radionuclides in the marine environments due to their ability to concentrate elements from the ambient water. There is quite a lot of data available on 137Cs in brown algae, especially for Fucus Vesiculosus. Fucus Vesiculosus is also commonly used to monitor the impact of the releases of 99Tc from the reprocessing plant in Sellafield. There is however a lack of data for other long-lived anthropogenic nuclides as 90Sr and Pu, and for natural occurring radionuclides. There is also a need for more knowledge about the mechanisms for uptake and accumulation of the different elements, and about different factors influencing the uptake. In this study activity concentrations of 137Cs, 40K, 7Be, 228Ac, 99Tc, 90Sr and 239/240Pu are measured in whole plants of Fucus vesiculosus and Ascophyllum nodosum collected over a period of one year from the south-eastern coast of Norway. Significant differences between the two species have been found. For 137Cs, 40K, 7Be, 228Ra and 239/240Pu, the activity concentrations were significantly higher in Fucus vesiculosus than in Ascophyllum nodosum, whereas for 99Tc the activity concentrations were higher in Ascophyllum nodosum than in Fucus vesiculosus. There were great seasonal variations in the concentrations of the measured radionuclides. For 99Tc there was also a difference in the temporal pattern for the two species. Possible uptake mechanisms will be discussed based on the results and on the known physiological differences between the two species. (author)

  5. Microscopic Calculations of 240Pu Fission

    Younes, W; Gogny, D

    2007-09-11

    Hartree-Fock-Bogoliubov calculations have been performed with the Gogny finite-range effective interaction for {sup 240}Pu out to scission, using a new code developed at LLNL. A first set of calculations was performed with constrained quadrupole moment along the path of most probable fission, assuming axial symmetry but allowing for the spontaneous breaking of reflection symmetry of the nucleus. At a quadrupole moment of 345 b, the nucleus was found to spontaneously scission into two fragments. A second set of calculations, with all nuclear moments up to hexadecapole constrained, was performed to approach the scission configuration in a controlled manner. Calculated energies, moments, and representative plots of the total nuclear density are shown. The present calculations serve as a proof-of-principle, a blueprint, and starting-point solutions for a planned series of more comprehensive calculations to map out a large set of scission configurations, and the associated fission-fragment properties.

  6. Association of fallout-derived 137Cs,90Sr and 239,240Pu with natural organic substances in soils

    Activity concentrations and associations of fallout-derived Cs, Sr and Pu in soils were investigated. The activity concentrations of 137Cs, 90Sr and 239,240Pu in volcanic ash soil were much higher than those in granite soil. They decreased with increasing depth in the soil. The activity ratios of 239,240Pu/137Cs and 90Sr/137Cs tended to increase slightly with increasing soil depth. Alkali extraction experiments with 0.1 M NaOH solution showed that the percentage activities of the fallout radionuclides found in the organic acid fractions were in the order 239,240Pu>90Sr>137Cs. The concentrations of 137Cs and 239,240Pu reacted with humic fractions were higher than those with fulvic fractions. In contrast to 137Cs and 239,240Pu,90Sr reacted more with fulvic fractions than with humic fractions. These results provide information about the effects of organic substances on the retention and migration of 137Cs,90Sr and 239,240Pu in soils under natural conditions

  7. Distribution and source of (129)I, (239)(,240)Pu, (137)Cs in the environment of Lithuania.

    Ežerinskis, Ž; Hou, X L; Druteikienė, R; Puzas, A; Šapolaitė, J; Gvozdaitė, R; Gudelis, A; Buivydas, Š; Remeikis, V

    2016-01-01

    Fifty five soil samples collected in the Lithuania teritory in 2011 and 2012 were analyzed for (129)I, (137)Cs and Pu isotopes in order to investigate the level and distribution of artificial radioactivity in Lithuania. The activity and atomic ratio of (238)Pu/((239,24)0)Pu, (129)I/(127)I and (131)I/(137)Cs were used to identify the origin of these radionuclides. The (238)Pu/(239+240)Pu and (240)Pu/(239)Pu ratios in the soil samples analyzed varied in the range of 0.02-0.18 and 0.18-0.24, respectively, suggesting the global fallout as the major source of Pu in Lithuania. The values of 10(-9) to 10(-6) for (129)I/(127)I atomic ratio revealed that the source of (129)I in Lithuania is global fallout in most cases though several sampling sites shows a possible impact of reprocessing releases. Estimated (129)I/(131)I ratio in soil samples from the southern part of Lithuania shows negligible input of the Chernobyl fallout. No correlation of the (137)Cs and Pu isotopes with (129)I was observed, indicating their different sources terms. Results demonstrate uneven distribution of these radionuclides in the Lithuanian territory and several sources of contamination i.e. Chernobyl accident, reprocessing releases and global fallout. PMID:26476410

  8. Precision of gamma-ray measurements of the effective specific power and effective {sup 240}Pu fraction of plutonium

    Sampson, T.E.

    1992-05-01

    This paper uses gamma-ray spectrometry data from replicate measurements on 40 plutonium-bearing samples to examine the repeatability of the effective {sup 240}Pu fraction ({sup 240}Pu{sub eff}) and the effective specific power (P{sub eff}) calculated from the isotopic distribution analyzed with gamma-ray spectrometry codes. The measurements were used to identify the error component arising from repeatability in the determination of the isotopic composition of plutonium in the sample and the contribution of the error component to the uncertainty in total plutonium mass measurements from neutron coincidence counting ({sup 240}Pu{sub eff}) and calorimetry (P{sub eff}). The 40 samples had {sup 240}Pu{sub eff} percentages ranging from 2 to 39% and P{sub eff} values ranging from 2 to 16 mW/g Pu. Four different gamma-ray spectrometry codes (FRAM, MGA, Blue Box, and PUJRC) were used to analyze the data (not all samples were analyzed with each code). All analyses showed that the % relative standard deviation of P{sub eff} was smaller than that of {sup 240}Pu{sub eff}. This result coupled with a cursory examination of uncertainties in coincidence counting of well-characterized samples and water-bath calorimetry errors for the same types of samples lead to the conclusion that smaller uncertainties will be present in the total plutonium mass determined by the combination of calorimetry/gamma-ray spectrometry than in the mass determined by coincidence counting/gamma-ray spectrometry. An additional examination of the biases arising from the {sup 240}Pu correlation used in the gamma-ray spectrometry codes also supported this conclusion. 17 refs.

  9. The pore water chemistry of sup(239,240)Pu and 137Cs on sediments of Buzzards Bay, Massachusetts

    The collection of large volumes of pore water and low level radiochemical measurements of sup(239,240)Pu and 137Cs have been combined to produce the first study of these fallout artificial radionuclides in marine pore waters. Profiles from box cores taken in June and September 1982 from Buzzards Bay, Mass., are reported along with profiles of many diagenetic constituents (i.e. SO42-, alkalinity, Fe, Mn, DOC, and nutrients). The sup(239,240)Pu pore water profile is characterized by a subsurface maximum of about 0.28 dpm/100 kg lying between 3 to 11 cm. Overlying seawater, in contrast, has an activity of 0.01 +- 0.02 dpm/100 kg. Below about 11 cm, the pore water sup(239,240)Pu distribution follows that of the solid phase which decreases rapidly with depth. The pore water profiles of 137Cs are characterized by a broad and deeply penetrating maximum where activities of about 35 to 40 dpm/100 kg extend from 3 to 20 cm. Overlying seawater, in contrast, has an activity of 17 to 24 dpm/100 kg. The 137Cs and sup(239,240)Pu pore water data show that there is preferential downward transport of 137Cs and that sup(239,240)Pu does not have an active diagenetic chemistry and is not significantly mobile in these coastal sediments. (author)

  10. Evaluation of 239+240Pu, 137Cs and natural 210Pb fallout in agricultural upland fields in Rokkasho, Japan

    The background distributions of 239+240Pu and 137Cs fallout in agricultural soil were investigated in Rokkasho where Japan's first commercial nuclear fuel reprocessing plant is now being constructed. The mean inventories of 239+240Pu and 137Cs in three fields with non-yam-cultivation history were 116 Bq x m-2 and 3.4 kBq x m-2, respectively. The mean atomic ratio of 240Pu/239Pu for all studied fields was 0.18±0.04, and was similar to that of global fallout. The 239+240Pu concentrations correlated very well with 137Cs (r = 0.97) in spite of heavy disturbance of the soil, and the activity ratio of 239+240Pu/137Cs was 0.037 ± 0.007, which is a typical value for global fallout. These results showed that the nuclides had similar behavior in agricultural upland fields in Rokkasho. Since 210Pb is steadily deposited from the atmosphere to the land, this nuclide could be an index for the degree of disturbance of a field and of soil lost from the field. The ratio of excess 210Pb inventory in the soil to the equivalent inventory of atmospheric 210Pb deposition was 96%, and indicated that soil was not lost from the cultivated fields. (author)

  11. Evaluation of neutron nuclear data for 240Pu

    Based on the experimental data evaluation and theoretical calculation, a complete set of neutron nuclear data for 240Pu has been recommended in the incident neutron energy range from 10-5 eV to 20 MeV for CENDL-2. The comparison of present evaluation with ENDF/B-6 and JENDL-3 has been carried out

  12. Measurement of the ${240}$Pu(n,f) reaction cross-section

    Following proposal CERN-INTC-2010-042 / INTC-P-280 (“Measurement of the fission cross-section of $^{240}$Pu and $^{242}$Pu at CERN’s n_TOF Facility”), the parallel measurement of the $^{240}$Pu(n,f) and $^{242}$Pu(n,f) reaction cross-sections was carried out at n_TOF EAR-1. While the $^{242}$Pu measurement was successful, unexpected sample-induced damage to the detectors caused by the high α-activity of the 240Pu samples resulted in a deterioration of the detector performance over the data taking period of several months, which compromised the measurement. This obstacle can be eliminated by performing the measurement in EAR-2, where the higher neutron flux will allow collecting data in a much shorter time, thus preventing the degradation of the detectors. In addition to this obvious advantage, the measurement would also benefit from the stronger suppression of the sample-induced α-background, due to the shorter times-of-flight involved.

  13. Perturbation in the 240Pu/239Pu global fallout ratio in local sediments following the nuclear accidents at Thule (Greenland) and Palomares (Spain).

    Mitchell, P I; León Vintró, L; Dahlgaard, H; Gascó, C; Sánchez-Cabeza, J A

    1997-08-25

    It is well established that the main source of the plutonium found in marine sediments throughout the Northern Hemisphere is global stratospheric fallout, characterized by a typical 240Pu/239Pu atom ratio of approximately 0.18. Measurement of perturbations in this ratio at various sites which had been subjected to close-in fallout, mainly from surface-based testing (e.g. Bikini Atoll, Nevada test site, Mururoa Atoll), has confirmed the feasibility of using this ratio to distinguish plutonium from different fallout sources. In the present study, the 240Pu/239Pu ratio has been examined in samples of sediment (and soil) collected at Thule (Greenland) and Palomares (Spain), where accidents involving the release and dispersion of plutonium from fractured nuclear weapons occurred in 1968 and 1966, respectively. The 240Pu/239Pu ratio was measured by high-resolution alpha spectrometry and spectral deconvolution, and confirmed in the case of the most active samples by high-resolution X-ray spectrometry. Only samples which displayed plutonium heterogeneities, i.e. hot particles or concentrations well in excess (at least two orders of magnitude) of those expected from global fallout, were selected for analysis. The analytical results showed that at Thule the mean 240Pu/239Pu atom ratio was 0.033 +/- 0.004 (n = 4), while at Palomares the equivalent ratio appeared to be significantly higher at 0.056 +/- 0.003 (n = 4). Both ratios are indicative of low burn-up plutonium and are consistent with those reported for weapons-grade plutonium. It is noteworthy that the mean 238Pu/239Pu activity ratio in the Thule samples, at 0.0150 +/- 0.0017 (n = 4), was also lower than that measured in the Palomares samples, namely, 0.0275 +/- 0.0012 (n = 4). The 241Pu/239Pu ratios were similarly different. Finally, the data show, in contrast to Palomares, that not all of the samples from the Thule accident site were contaminated with plutonium of identical isotopic composition. PMID:9241884

  14. The inflow of 238Pu and 239+240Pu from the Vistula River catchment area to the Baltic Sea

    The aim of the work was to estimate plutonium inflow from the Vistula River's catchments area to the Baltic Sea. There were differences in plutonium activities depending on season and sampling site. The highest activities of 238Pu and 239+240Pu were transported from the Vistula River watershed to the Baltic Sea in spring and the lowest in summer. Annually, the southern Baltic Sea is enriched via the Vistula River with 10.3 MBq of 238Pu and 89.0 MBq of 239+240Pu. The enhanced concentration of plutonium in water from the Vistula River is the result of its runoff from the Vistula drainage area, mostly from snowmelt, enhanced rainfalls and leached materials from river bed. - Highlights: → We estimated plutonium inflow from the Vistula River catchment area to the Baltic Sea. → We found differences in Pu activities depending on season and sampling site. → The highest amount of 239 + 240Pu was transported in spring and the lowest in summer. → Annually, the southern Baltic Sea is enriched with 89.0 MBq of 239 + 240Pu. → Enhanced Pu amount in water came from snowmelt, rainfalls and leached materials.

  15. Assessment of 238Pu and 239+240Pu, in marine sediments of the oceans Atlantic and Pacific of Guatemala

    In this investigation samples of marine sediments were taken from 14 places representatives of the oceans coast of Guatemala. For the assesment of 238Pu and 239+240Pu in sediments a radiochemical method was used to mineralize sediments and by ionic interchange it was separated from other elements, after that an electrodeposition of plutonium was made in metallic discs. The radioactivity of plutonium was measured by alpha spectrometry system and the alpha spectrums were obtained. The levels of plutonium are not higher than other countries that shown contamination. The contamination of isotope of 239+240Pu is higher than 238Pu and the contamination by two isotopes of plutonium is higher in the Atlantic than the Pacific ocean

  16. Model testing of radioactive contamination by 90Sr, 137Cs and 239,240Pu of water and bottom sediments in the Techa River (Southern Urals, Russia)

    This paper presents results of testing models for the radioactive contamination of river water and bottom sediments by 90Sr, 137Cs and 239,240Pu. The scenario for the model testing was based on data from the Techa River (Southern Urals, Russia), which was contaminated as a result of discharges of liquid radioactive waste into the river. The endpoints of the scenario were model predictions of the activity concentrations of 90Sr, 137Cs and 239,240Pu in water and bottom sediments along the Techa River in 1996. Calculations for the Techa scenario were performed by six participant teams from France (model CASTEAUR), Italy (model MARTE), Russia (models TRANSFER-2, CASSANDRA, GIDRO-W) and Ukraine (model RIVTOX), all using different models. As a whole, the radionuclide predictions for 90Sr in water for all considered models, 137Cs for MARTE and TRANSFER-2, and 239,240Pu for TRANSFER-2 and CASSANDRA can be considered sufficiently reliable, whereas the prediction for sediments should be considered cautiously. At the same time the CASTEAUR and RIVTOX models estimate the activity concentrations of 137Cs and 239,240Pu in water more reliably than in bottom sediments. The models MARTE (239,240Pu) and CASSANDRA (137Cs) evaluated the activity concentrations of radionuclides in sediments with about the same agreement with observations as for water. For 90Sr and 137Cs the agreement between empirical data and model predictions was good, but not for all the observations of 239,240Pu in the river water-bottom sediment system. The modelling of 239,240Pu distribution proved difficult because, in contrast to 137Cs and 90Sr, most of models have not been previously tested or validated for plutonium

  17. Behaviors and transfers of anthropogenic radionuclides (137Cs, 239+240Pu and 241Am) in a protected alpine wetland (France)

    The aim of this study is to confirm and increase the knowledge on anthropogenic radionuclide (RN) behavior (137Cs, 239+240Pu, 241Am) in natural compartments (artificial pool in a protected upland area). The novelty lies on comparisons of the three main compartments (pool water, soil, sediments) of this original mountainous site. Migration processes and transfers were particularly detailed in the light of two processes: lixiviation and leaching. Regarding 238U, anthropogenic RNs, lithology, organic matter contents, sedimentation rates (210Pb) and isotopic mass balances, RNs are mainly transported by leaching processes with higher 241Am in-depth mobility compared to 137Cs (intermediate for 239+240Pu). (author)

  18. Plutonium concentration and 240Pu/239Pu atom ratio in biota collected from Amchitka Island, Alaska: recent measurements using ICP-SFMS

    Three underground nuclear tests, including the Unites States' largest, were conducted on Amchitka Island, Alaska. Monitoring of the radiological environment around the island is challenging because of its remote location. In 2008, the Department of Energy (DOE) Office of Legacy Management (LM) became responsible for the long term maintenance and surveillance of the Amchitka site. The first DOE LM environmental survey occurred in 2011 and is part of a cycle of activities that will occur every 5 years. The University of Alaska Fairbanks, a participant in the 2011 study, provided the lichen (Cladonia spp.), freshwater moss (Fontinalis neomexicanus), kelp (Eualaria fistulosa) and horse mussel (Modiolus modiolus) samples from Amchitka Island and Adak Island (a control site). These samples were analyzed for 239Pu and 240Pu concentration and 240Pu/239Pu atom ratio using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). Plutonium concentrations and 240Pu/239Pu atom ratios were generally consistent with previous terrestrial and marine studies in the region. The 239+240Pu levels (mBq kg−1, dry weight) ranged from 3.79 to 57.1 for lichen, 167–700 for kelp, 27.9–148 for horse mussel, and 560–573 for moss. Lichen from Adak Island had higher Pu concentrations than Amchitka Island, the difference was likely the result of the higher precipitation at Adak compared to Amchitka. The 240Pu/239Pu atom ratios were significantly higher in marine samples compared to terrestrial and freshwater samples (t-test, p 240Pu/239Pu ratios in terrestrial samples are within the range of global fallout. • Elevated 240Pu/239Pu in marine samples was characteristic of North Pacific Ocean. • Potential sources of enriched Pu to the marine environment regionally are suggested. • Pu ratios cannot by themselves explain the enriched Pu in seawater around Amchitka

  19. Radioecologycal study of {sup 239/240}Pu in Bangka Island and Muria Peninsula: Determination of {sup 239/240}Pu in marine sediment and seawater as part of baseline data collecting for sitting of candidates of first Indonesia NPP

    Suseno, Heny, E-mail: henis@batan.go.id [Radioactive Waste Technology Center - The Indonesian National Nuclear Energy Agency (Indonesia); Wisnubroto, Djarot S. [The Indonesian National Nuclear Energy Agency (Indonesia)

    2014-03-24

    Radioisotope Pu-239/240 are alpha emitting nuclides important indicators of radioactive contamination of the marine environment. Global fallout is the main source of plutonium in the marine environment. There are very limited study on {sup 239/240}Pu in Indonesia coastal environments. The data of this radioisotopes is needed for baseline data of nuclear power plant (NPP) site candidates both in Bangka Island and Muria Peninsula. Bottom sediments play an important role in radioecological studies of the marine environment because a large proportion of radioactive substances entering the sea is adsorbed over time onto suspended particulate matter and deposited in sediments. Plutonium is particle reactive and deposited in marine sediment. Radioisotope {sup 239/240}Pu was determinated by alpha spectrometry after radiochemical procedure that was performed in both water and marine sediment from Bangka Island and Muria Peninsula. The sediment baseline of concentration {sup 239/240}Pu in Bangka Island and Muria Peninsula were range from 0.013 to 0.021 Bq.kg{sup −1} and 0.018 to 0.024 Bq.kg{sup −1} respectively. The water baseline concentration this isotope were range from 2.73 to 4.05 mBq.m{sup −3} and 2.98 to 4.50 mBq.m{sup −3}.

  20. Spatial distribution of 241Am, 137Cs, 238Pu, 239,240Pu and 241Pu over 17 year periods in the Ravenglass saltmarsh, Cumbria, UK

    Ninety five surface scrape samples were collected at the Ravenglass saltmarsh and analysed for radionuclides by alpha spectrometry (238Pu and 239,240Pu), gamma spectrometry (241Am and 137Cs) and liquid scintillation counting (241Pu). Both 241Am and 137Cs activities are compared with those reported by Horrill [1983. Concentrations and spatial distribution of radioactivity in an ungrazed saltmarsh. In: Coughtrey, P.J. (Ed.), Ecological Aspects of Radionuclide Release. British Ecological Society Special Publication No. 3. Blackwell, Oxford, pp. 119-215.] Significant decreases in activities for both radionuclides were observed which is caused by the declining levels of discharges from the Sellafield nuclear reprocessing plant since the 1980s. It has been concluded that the spatial distribution of these radionuclides are controlled by the tidal currents and the clay contents in the sediments. There is evidence of surface erosion of the saltmarsh and redistribution of radionuclides in the saltmarsh using isotopic ratios of measured Pu.

  1. Pu-239 and Pu-240 inventories and Pu-240/ Pu-239 atom ratios in the water column off Sanriku, Japan.

    Yamada, Masatoshi; Zheng, Jian; Aono, Tatsuo

    2013-04-01

    A magnitude 9.0 earthquake and subsequent tsunami occurred in the Pacific Ocean off northern Honshu, Japan, on 11 March 2011 which caused severe damage to the Fukushima Dai-ichi Nuclear Power Plant. This accident has resulted in a substantial release of radioactive materials to the atmosphere and ocean, and has caused extensive contamination of the environment. However, no information is available on the amounts of radionuclides such as Pu isotopes released into the ocean at this time. Investigating the background baseline concentration and atom ratio of Pu isotopes in seawater is important for assessment of the possible contamination in the marine environment. Pu-239 (half-life: 24,100 years), Pu-240 (half-life: 6,560 years) and Pu-241 (half-life: 14.325 years) mainly have been released into the environment as the result of atmospheric nuclear weapons testing. The atom ratio of Pu-240/Pu-239 is a powerful fingerprint to identify the sources of Pu in the ocean. The Pu-239 and Pu-240 inventories and Pu-240/Pu-239 atom ratios in seawater samples collected in the western North Pacific off Sanriku before the accident at Fukushima Dai-ichi Nuclear Power Plant will provide useful background baseline data for understanding the process controlling Pu transport and for distinguishing additional Pu sources. Seawater samples were collected with acoustically triggered quadruple PVC sampling bottles during the KH-98-3 cruise of the R/V Hakuho-Maru. The Pu-240/Pu-239 atom ratios were measured with a double-focusing SF-ICP-MS, which was equipped with a guard electrode to eliminate secondary discharge in the plasma and to enhance overall sensitivity. The Pu-239 and Pu-240 concentrations were 2.07 and 1.67 mBq/m3 in the surface water, respectively, and increased with depth; a subsurface maximum was identified at 750 m depth, and the concentrations decreased with depth, then increased at the bottom layer. The total Pu-239+240 inventory in the entire water column (depth interval 0

  2. 40K, 137Cs, 90Sr, 238,239+240Pu and 241Am in mammals' skulls from owls' pellets and owl skeletons in Poland

    Skulls of small mammals belonging to two species of rodents and three species of insectivores collected in Eastern Poland were the subject of the present investigation. The skulls were separated from owl pellets. Activities of 40K, 137Cs, 90Sr, 238,239+240Pu and 241Am were determined by means of gamma spectrometry as well as liquid scintillation spectrometry or alpha spectrometry along with relevant radiochemical procedures. A detailed description of the procedures is provided. The research was supplied with the analysis of three skeletons of owls. No measurable difference between the skulls of rodents and insectivorous animals with regard to activity of any of the examined radionuclides was found. No accumulation effect in the owl skeletons was detected. Though measured activities of 137Cs and 40K for the skulls were of the same magnitude as those found previously for large wild herbivorous animals from typical locations in Poland, those for 90Sr were even lower than previously determined. A big difference was found for activities of plutonium and americium isotopes. Their mean activities were higher by an order of magnitude when compared to the examined previously values. The maximum 239+240Pu activity was equal to 97.5±7.7 mBq/kg, with 65% of it originating from global fallout. Relatively high content of transuranic elements found for rodents and insectivorous mammals seems to be unrelated to their feeding habits and should rather be attributed to the living conditions. It is suggested that small mammals, together with tiny soil particles present in mid-soil living tunnels, can inhale the transuranic elements

  3. Plutonium isotopes in sediments from the Sudanese coast of the Red Sea

    Activity concentrations of Pu isotopes in surface marine sediments collected from the Sudanese coast of the Red Sea is presented. The following concentration ranges were determined: 238Pu, 4.7-28.6 mBq/kg; 239+240Pu, 53-343 mBq/kg dry weight. The average activity ratios of 238Pu/239+240Pu (0.075 ± 0.045 mBqk/kg) and 239+240Pu/137Cs (0.026 ± 0.025 mBq/kg) are appropriately comparable to the literature values that are characteristic of the global fallout from the atmospheric nuclear weapon tests. However, 239/240Pu/137Cs ratio in sediments collected from the biologically rich fringing reef is an order of magnitude higher compared to other sampling locations. (author)

  4. Concentrations of sup(239,240)Pu and 241Am in drinking water and organic fertilizer

    As part of an investigation of the chemistry and aquatic distribution of fallout-derived sup(239,240)Pu and 241Am in the aquatic environment a study has been made of the concentration of these nuclides in the drinking water and organic fertilizer, distributed to the populace of the Chicago area. The results clearly indicate that the concentration of sup(239,240)Pu is always lower in the water which has been treated at the Chicago Central Water Filtration Plant than in the raw water before treatment. Raw water levels are consistent with normal levels of sup(239,240)PU found in Lake Michigan waters which are approx 6 orders of magnitude below the maximum permissible concentration standard for drinking water. An additional possible source of sup(239,240)Pu and 241Am to humans can be through the distribution of the organic fertilizer, 'Nu Earth', by the Metropolitan Sanitary District, free of charge, for the use in home gardens. 'Nu Earth' consists primarily of sediment from an Imhoff Process which has been air-dried and aged in large, open-air piles. Samples of this organic fertilizer were analysed for sup(239,240)Pu and 241Am. The results indicate that there is little evidence to indicate that sup(239,240)Pu in drinking water or sup(239,240)Pu and 241Am from organic sludge will be health hazards in the Chicago area under current conditions. (U.K.)

  5. 239+240Pu and 90Sr deposition densities in undisturbed surface soil in Vietnam

    The study's goal is determination of 239+240Pu and 90Sr deposition densities from known distribution of 137Cs deposition density. The tasks done include: simultaneous determination of 239+240Pu, 90Sr and 137Cs deposition densities in undisturbed surface soil layer having depth to 20 cm and use it as basis for determining the ratios of deposition densities 239+240Pu/137Cs and 90Sr/137Cs; studying the impact of soil parameters such as soil texture, content of organic matter, Humic, Fulvic as well as of geography parameters such as latitude, longitude, annual rainfall to the variation of these ratios. (NHA)

  6. Worldwide data on fluxes of 239,240Pu, 238Pu to the oceans

    According to measurements (GEOSECS) the world's oceans contain approximately 16 PBq 239,240Pu, of which one-fourth is in the Atlantic and three-fourths in the Pacific Ocean. The expected inventory (from nuclear weapons testing) in the world's oceans is 12 PBq 239,240Pu including local fallout at the test sites. In the Irish Sea a local contamination of 0.3 PBq 239,240Pu from the Sellafield reprocessing plant resides in the sediments. No other sources than fallout and reprocessing add significantly to the 239,240Pu inventories in the oceans. The discrepancy between measurements and expectations are assumed to be due to an underestimate of the rainfall and dry fallout (seaspray) and thus of the Pu-deposition over the oceans, but may also to some degree be due to inadequate sampling

  7. Precision of gamma-ray measurements of the effective specific power and effective 240Pu fraction of plutonium

    This paper uses gamma-ray spectrometry data from replicate measurements on 40 plutonium-bearing samples to examine the repeatability of the effective 240Pu fraction (240Pueff) and the effective specific power (Peff) calculated from the isotopic distribution analyzed with gamma-ray spectrometry codes. The measurements were used to identify the error component arising from repeatability in the determination of the isotopic composition of plutonium in the sample and the contribution of the error component to the uncertainty in total plutonium mass measurements from neutron coincidence counting (240Pueff) and calorimetry (Peff). The 40 samples had 240Pueff percentages ranging from 2 to 39% and Peff values ranging from 2 to 16 mW/g Pu. Four different gamma-ray spectrometry codes (FRAM, MGA, Blue Box, and PUJRC) were used to analyze the data (not all samples were analyzed with each code). All analyses showed that the % relative standard deviation of Peff was smaller than that of 240Pueff. This result coupled with a cursory examination of uncertainties in coincidence counting of well-characterized samples and water-bath calorimetry errors for the same types of samples lead to the conclusion that smaller uncertainties will be present in the total plutonium mass determined by the combination of calorimetry/gamma-ray spectrometry than in the mass determined by coincidence counting/gamma-ray spectrometry. An additional examination of the biases arising from the 240Pu correlation used in the gamma-ray spectrometry codes also supported this conclusion. 17 refs

  8. Latitudinal distribution and sedimentation of 90Sr, 137Cs, 241Am and 239,240Pu in bottom sediment of the Northwest Pacific Ocean

    As a part of the Worldwide Marine Radioactivity Studies (WOMARS) of the International Atomic Energy Agency's Marine Environment Laboratory (IAEA-MEL) in Monaco, bottom sediment samples were collected along with water column samples in 1997 from the Northwest Pacific Ocean, and were analysed for 90Sr, 137Cs, 239,240Pu and 241Am contents in order to identify current distribution patterns and inventories, and to elucidate sources of these radionuclides in the region where the past US nuclear weapons tests were carried out. This study complements a previous reports on bottom sediments and water column. All the reported sediment data including data from 1997 cruise revealed that sedimentary 239+240Pu and 241Am concentrations peaked both in the latitudinal bands between 10-20 deg. N and 30-40 deg. N, and 137Cs and 90Sr in the latitudinal band between 30-40 deg. N. The latitudinal bands between 10-20 deg. N and 30-40 deg. N correspond to the major areas affected by close-in fallout and global fallout, respectively. Sediment inventories of 239,240Pu and 241Am exceeded or nearly equalled their overlying water inventories near the Bikini Atoll, however, in mid latitudes, more than 70% of 239,240Pu still remains in the water column. Sediment inventories of 137Cs and 90Sr account for about ten and less than five percent of the water column inventories, respectively. 241Am inventories in sediments exceeded those of the water column. The activity ratios of 137Cs/90Sr and 241Am/239,240Pu in sediments were higher than of the global fallout ratios. 90Sr content in the bottom sediments also appears to be controlled by the carbonate contents of the sea floor. The relative contribution of global and close-in fallouts to the total 239,240Pu was estimated using a two end-member mixing model based on the atom ratios of 240Pu/239Pu. The contribution of close-in fallout in sediment appears to be about 56 % for the latitudinal belt 10-20 deg. N. It is not unexpected that close-in fallout Pu

  9. Latitudinal distribution and sedimentation of 90Sr, 137Cs, 241Am and 239,240Pu in bottom sediment of the Northwest Pacific Ocean

    As a part of the Worldwide Marine Radioactivity Studies (WOMARS) of the International Atomic Energy Agency's Marine Environment Laboratory (IAEA-MEL) in Monaco, bottom sediment samples were collected along with water column samples in 1997 from the Northwest Pacific Ocean, and were analysed for 90Sr, 137Cs, 239,240Pu and 241Am contents in order to identify current distribution patterns and inventories, and to elucidate sources of these radionuclides in the region where the past US nuclear weapons tests were carried out. This study complements a previous reports on bottom sediments and water column. All the reported sediment data including data from 1997 cruise revealed that sedimentary 239+240Pu and 241Am concentrations peaked both in the latitudinal bands between 10-20 deg. N and 30-40 deg. N, and 137Cs and 90Sr in the latitudinal band between 30-40 deg. N. The latitudinal bands between 10-20 deg N and 30-40 deg. N correspond to the major areas affected by close-in fallout and global fallout, respectively. Sediment inventories of 239+240Pu and 241Am exceeded or nearly equalled their overlying water inventories near the Bikini Atoll, however, in mid latitudes, more than 70% of 239+240Pu still remains in the water column. Sediment inventories of 137Cs and 90Sr account for about ten and less than five percent of the water column inventories, respectively. 241Am inventories in sediments exceeded those of the water column. The activity ratios of 137Cs/90Sr and 241Am/239,240Pu in sediments were higher than of the global fallout ratios. 90Sr content in the bottom sediments also appears to be controlled by the carbonate contents of the sea floor. The relative contribution of global and close-in fallouts to the total 239,240Pu was estimated using a two end-member mixing model based on the atom ratios of 240Pu/239Pu. The contribution of close-in fallout in sediment appears to be about 56 % for the latitudinal belt 10-20 deg. N. It is not unexpected that close-in fallout Pu

  10. 137Cs, 239,240Pu and 241Am in boreal forest soil and their transfer into wild mushrooms and berries

    Profiles of podzolic soil from boreal forests were sampled from eight sites in Finland and the distribution of 137Cs in the soil layers was determined. In addition, 239,240Pu and 241Am were determined from two soil profiles taken at one sampling site. Inventories of 137Cs in the soil profiles varied between 1.7 kBq/m2 and 42 kBq/m2, reflecting known variation in 137Cs fallout from the Chernobyl accident. The highest proportions of the radionuclides were found in the organic layer at a depth of less than 5 cm, which on average contained 47% of 137Cs, 76% of 239,240Pu and 79% of 241Am. In the litter, clearly higher proportions of 137Cs were found compared to 239,240Pu and 241Am, probably indicating its more effective recycling from the organic layer back to the surface. Only very minor proportions of 137Cs were recorded below 20 cm. The concentration of 137Cs in the soil profiles could be approximated with a declining logarithmic trend. The activity concentrations of 137Cs were determined for six wild mushroom species and three wild berry species at two sites, as well as the aggregated transfer factors and the distribution of 137Cs between their various parts. In addition, 239,240Pu and 241Am were determined in one mushroom and three berry species at one site. Very high concentrations of 137Cs, up to 20 kBq/kg (d.w.), were found in mushrooms, and their transfer factors were between 0.1 m2/kg and 1.0 m2/kg. In berries, the transfer factors were an order of magnitude lower. 137Cs accumulated more in the caps of mushrooms and in the fruits of berries than in other parts. Transfer factors for 239,240Pu and 241Am were two to three orders of magnitude lower than those of 137Cs. - Highlights: ► 137Cs, 239,240Pu and 241Am mainly concentrated in organic layer in podzolic soil. ► Distribution of 137Cs in the upper 20 cm soil follows exponential declining trend. ► 137Cs concentrates into mushrooms but varies considerably between species. ► 137Cs concentrates in mushroom

  11. Model testing of radioactive contamination by {sup 90}Sr, {sup 137}Cs and {sup 239,240}Pu of water and bottom sediments in the Techa River (Southern Urals, Russia)

    Kryshev, I.I. [Scientific and Production Association ' Typhoon' , 82 Lenin Ave., Obninsk, Kaluga Region, 249038 (Russian Federation)], E-mail: ecomod@obninsk.com; Boyer, P.; Monte, L.; Brittain, J.E.; Dzyuba, N.N.; Krylov, A.L.; Kryshev, A.I.; Nosov, A.V.; Sanina, K.D.; Zheleznyak, M.I. [Scientific and Production Association ' Typhoon' , 82 Lenin Ave., Obninsk, Kaluga Region, 249038 (Russian Federation)

    2009-03-15

    This paper presents results of testing models for the radioactive contamination of river water and bottom sediments by {sup 90}Sr, {sup 137}Cs and {sup 239,240}Pu. The scenario for the model testing was based on data from the Techa River (Southern Urals, Russia), which was contaminated as a result of discharges of liquid radioactive waste into the river. The endpoints of the scenario were model predictions of the activity concentrations of {sup 90}Sr, {sup 137}Cs and {sup 239,240}Pu in water and bottom sediments along the Techa River in 1996. Calculations for the Techa scenario were performed by six participant teams from France (model CASTEAUR), Italy (model MARTE), Russia (models TRANSFER-2, CASSANDRA, GIDRO-W) and Ukraine (model RIVTOX), all using different models. As a whole, the radionuclide predictions for {sup 90}Sr in water for all considered models, {sup 137}Cs for MARTE and TRANSFER-2, and {sup 239,240}Pu for TRANSFER-2 and CASSANDRA can be considered sufficiently reliable, whereas the prediction for sediments should be considered cautiously. At the same time the CASTEAUR and RIVTOX models estimate the activity concentrations of {sup 137}Cs and {sup 239,240}Pu in water more reliably than in bottom sediments. The models MARTE ({sup 239,240}Pu) and CASSANDRA ({sup 137}Cs) evaluated the activity concentrations of radionuclides in sediments with about the same agreement with observations as for water. For {sup 90}Sr and {sup 137}Cs the agreement between empirical data and model predictions was good, but not for all the observations of {sup 239,240}Pu in the river water-bottom sediment system. The modelling of {sup 239,240}Pu distribution proved difficult because, in contrast to {sup 137}Cs and {sup 90}Sr, most of models have not been previously tested or validated for plutonium.

  12. Neutron-induced fission cross section of 240Pu from 0.5 MeV to 3 MeV

    Salvador-Castiñeira, P.; Bryś, T.; Eykens, R.; Hambsch, F.-J.; Göök, A.; Moens, A.; Oberstedt, S.; Sibbens, G.; Vanleeuw, D.; Vidali, M.; Pretel, C.

    2015-07-01

    240Pu has recently been pointed out by a sensitivity study of the Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA) to be one of the isotopes whose fission cross section lacks accuracy to meet the upcoming needs for the future generation of nuclear power plants (GEN-IV). In the High Priority Request List (HPRL) of the OECD, it is suggested that the knowledge of the 240Pu(n ,f ) cross section should be improved to an accuracy within 1-3 %, compared to the present 5%. A measurement of the 240Pu cross section has been performed at the Van de Graaff accelerator of the Joint Research Center (JRC) Institute for Reference Materials and Measurements (IRMM) using quasi-monoenergetic neutrons in the energy range from 0.5 MeV to 3 MeV. A twin Frisch-grid ionization chamber (TFGIC) has been used in a back-to-back configuration as fission fragment detector. The 240Pu(n ,f ) cross section has been normalized to three different isotopes: 237Np(n ,f ) , 235U (n ,f ) , and 238U (n ,f ) . Additionally, the secondary standard reactions were benchmarked through measurements against the primary standard reaction 235U (n ,f ) in the same geometry. A comprehensive study of the corrections applied to the data and the associated uncertainties is given. The results obtained are in agreement with previous experimental data at the threshold region. For neutron energies higher than 1 MeV, the results of this experiment are slightly lower than the ENDF/B-VII.1 evaluation, but in agreement with the experiments of Laptev et al. (2004) as well as Staples and Morley (1998).

  13. Measurement of the fission cross-section of $^{240}$Pu and $^{242}$Pu at CERN's n_TOF Facility

    Pavlik, A F; Gonzalez romero, E M

    The n_TOF Collaboration proposes to continue the fission program, already started in 2002-2004, taking advantage of the newly constructed Work Sector Type A, with the measurement of the two isotopes : $^{240}$ Pu and $^{242}$ Pu. They are both of major importance for reactor physics applications and are included in the Nuclear Energy Agency (NEA) High Priority List [1], in the NEA WPEC Subgroup 26 Report on the accuracy of nuclear data for advanced reactor designe [2] and in the EU 6$^{th}$ Framework Programme IP-EUROTRANS/NUDATRA reports [3]. Based on those requests, the measurement of the fission cross-section of the two Pu isotopes is one of the objectives of the project ANDES of the FP7 EURATOM program [4].

  14. Simultaneous measurement of {sup 239}Pu, {sup 240}Pu, {sup 241}Pu, and {sup 242}Pu by high resolution inductively coupled plasma mass spectrometer (HR ICP-MS) in marine sediments; Mesure des isotopes du plutonium des sediments marins par spectrometrie de masse a plasma couple inductivement haute resolution (HR ICP-MS)

    Bruneau, F

    1999-07-01

    Transuranics elements are of particular interest in radioecological studies because of their radiotoxicity and their potential use to decipher source fingerprints and transport processes. The simultaneous measurement of {sup 239}Pu, {sup 240}Pu, {sup 241}Pu, and {sup 242}Pu in environmental samples requires a specific chemical procedure. This work deals with an analytical procedure which yields a very high grade of purification of Pu suitable for ultra low level detection by HR ICP-MS, from marine sediments. After the elimination of major elements (Fe, Al, Mg...) by a first chromatographic separation, a new device of purification by solvent extraction and concentration by a second chromatographic separation is used to obtain a concentrated and high purified solution of plutonium. The chemical procedure have been validated on IAEA certified sediment samples and on sediment samples collected in the roads of Cherbourg which had been previously analysed by other techniques (a spectrometry and thermo-ionisation mass spectrometer). (author)

  15. Laboratory studies of the diagenesis and mobility of sup(239,240)Pu and 137Cs in nearshore sediments

    Controlled laboratory experiments have been used to study the diagenetic chemistry of sup(239,240)Pu, 137Cs and 55Fe. Experiments using Buzzards Bay sediments in small tanks show that sulfate reduction is accompanied by the production of large pore water concentration gradients of alkalinity, phosphate, ammonia and dissolved organic carbon and the formation of subsurface maxima in Fe and Mn. These pore water profiles demonstrate that bacterially-mediated processes of organic matter degradation and redox reactions can be simulated in the laboratory. A vertical profile of 55Fe in pore waters is reported for the first time: it follows the profile of stable Fe and as such has a large subsurface maximum between 2 to 4 cm depth. Comparison of 55Fe/Fe ratios in sediments and pore waters shows that there is preferential solubilization of 55Fe over stable Fe. The pore water activities of sup(239,240)Pu show no gradients within the large uncertainties of the counting statistics, but are two to four times higher than Buzzards Bay seawater. The activity of 137Cs in the pore water profile is constant within the large counting uncertainties and is twice that of Buzzards Bay seawater. Cs-137 does not appear to be involved in diagenetic chemistry but may increase in pore waters as a result of ion exchange reactions. (author)

  16. Gamma-emitters 90Sr, 238,239+240Pu and 241Am in bones and liver of eagles from Poland

    The present study focused on analyzing samples of bones, livers and kidneys of European white-tailed eagles (Haliaetus albicilla) and lesserspotted eagle (Aquila pomarina). Bone samples were collected for both species, from 7 and 2 individuals, respectively, whereas liver and kidney samples for white-tailed eagle species only, 2 and 1 individuals, respectively. The samples were analyzed for the presence of gamma-emitters and then for 90Sr, 238Pu, 239+240Pu and 241Am. The applied radiochemical method is presented. Activity concentration in ashen bones (600 deg C) for 90Sr ranged from 4.6±1.2 to 31.0±2.5 Bq/kg, for 239+240Pu from 238Pu from 241Am from 239+240Pu activity concentration of 78±9 mBq/kg (for fresh weight) was recorded in a single kidney sample. The liver samples showed activities of magnitude at least one order lower. No clear correlations were found between the activities of different radionuclides. (author)

  17. Spatial distributions of {sup 137}Cs and {sup 239+240}Pu in surface seawater within the Exclusive Economic Zone of East Coast Peninsular Malaysia

    Ahmad, Zaharudin, E-mail: zahar@nuclearmalaysia.gov.m [Radiochemistry and Environmental Group, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang (Malaysia); Mei-Wo, Yii; Abu Bakar, Ahmad Sanadi; Shahar, Hidayah [Radiochemistry and Environmental Group, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang (Malaysia)

    2010-09-15

    The studies of {sup 137}Cs and {sup 239+240}Pu distributions in surface seawater at South China Sea within the Exclusive Economic Zone (EEZ) of Peninsular Malaysia were carried out in June 2008. The analysis results will serve as additional information to the expanded baseline data for Malaysia's marine environment. Thirty locations from extended study area were identified in the EEZ from which large volumes of surface seawater samples were collected. Different co-precipitation techniques were employed to concentrate cesium and plutonium separately. A known amount of {sup 134}Cs and {sup 242}Pu tracers were used as yield determinant. The precipitate slurry was collected and oven dried at 60 {sup o}C for 1-2 days. Cesium precipitate was fine-ground and counted using gamma-ray spectrometry system at 661.62 keV, while plutonium was separated from other radionuclides using anion exchange, electrodeposited and counted using alpha spectrometry. The activity concentrations of {sup 137}Cs and {sup 239+240}Pu were in the range of 3.40-5.89 Bq/m{sup 3} and 2.3-7.9 mBq/m{sup 3}, respectively. The {sup 239+240}Pu/{sup 137}Cs ratios indicate that there are no new inputs of these radionuclides into the area.

  18. Spatial distributions of 137Cs and 239+240Pu in surface seawater within the Exclusive Economic Zone of East Coast Peninsular Malaysia

    The studies of 137Cs and 239+240Pu distributions in surface seawater at South China Sea within the Exclusive Economic Zone (EEZ) of Peninsular Malaysia were carried out in June 2008. The analysis results will serve as additional information to the expanded baseline data for Malaysia's marine environment. Thirty locations from extended study area were identified in the EEZ from which large volumes of surface seawater samples were collected. Different co-precipitation techniques were employed to concentrate cesium and plutonium separately. A known amount of 134Cs and 242Pu tracers were used as yield determinant. The precipitate slurry was collected and oven dried at 60 oC for 1-2 days. Cesium precipitate was fine-ground and counted using gamma-ray spectrometry system at 661.62 keV, while plutonium was separated from other radionuclides using anion exchange, electrodeposited and counted using alpha spectrometry. The activity concentrations of 137Cs and 239+240Pu were in the range of 3.40-5.89 Bq/m3 and 2.3-7.9 mBq/m3, respectively. The 239+240Pu/137Cs ratios indicate that there are no new inputs of these radionuclides into the area.

  19. (236)U and (239,)(240)Pu ratios from soils around an Australian nuclear weapons test site.

    Tims, S G; Froehlich, M B; Fifield, L K; Wallner, A; De Cesare, M

    2016-01-01

    The isotopes (236)U, (239)Pu and (240)Pu are present in surface soils as a result of global fallout from nuclear weapons tests carried out in the 1950's and 1960's. These isotopes potentially constitute artificial tracers of recent soil erosion and sediment movement. Only Accelerator Mass Spectrometry has the requisite sensitivity to measure all three isotopes at these environmental levels. Coupled with its relatively high throughput capabilities, this makes it feasible to conduct studies of erosion across the geographical extent of the Australian continent. In the Australian context, however, global fallout is not the only source of these isotopes. As part of its weapons development program the United Kingdom carried out a series of atmospheric and surface nuclear weapons tests at Maralinga, South Australia in 1956 and 1957. The tests have made a significant contribution to the Pu isotopic abundances present in the region around Maralinga and out to distances ∼1000 km, and impact on the assessment techniques used in the soil and sediment tracer studies. Quantification of the relative fallout contribution derived from detonations at Maralinga is complicated owing to significant contamination around the test site from numerous nuclear weapons safety trials that were also carried out around the site. We show that (236)U can provide new information on the component of the fallout that is derived from the local nuclear weapons tests, and highlight the potential of (236)U as a new fallout tracer. PMID:26141189

  20. Plutonium isotopes in the surface air in Japan

    Plutonium isotope concentrations in the surface air at Tsukuba, Japan are reported during the period from 1981 to the end of 1986. The 239,240Pu concentration in the surface air, which showed a marked seasonal variation with a spring maximum and fall minimum, decreased until the end of 1985 according to the stratospheric residence time of 1.15 years. In May 1986, elevated 239,240Pu concentrations with high 238Pu/239,240Pu activity ratios were observed. The serial trend of plutonium concentration in the surface air is similar to the concentrations of the Chernobyl-released radionuclides. These findings suggest that a significant part of the plutonium in the surface air in May 1986 was due to the Chernobyl fallout. (author) 15 refs.; 2 figs.; 3 tabs

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

    Strumińska-Parulska D. I.

    2013-04-01

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

  2. A comparative study of 239,240Pu in soil near the former Rocky Flats Nuclear Weapons Facility, Golden, CO

    The Rocky Flats Nuclear Weapons Plant near Golden, CO released plutonium into the environment during almost 40 years of operation. Continuing concern over possible health impacts of these releases has been heightened by lack of public disclosure of the US Department of Energy (DOE) activities. A dose reconstruction study for the Rocky Flats facilities, begun in 1990, provided a unique opportunity for concerned citizens to design and implement field studies without participation of the DOE, its contractors, or other government agencies. The Citizens Environmental Sampling Committee was formed in late 1992 and conducted a field sampling program in 1994. Over 60 soil samples, including both surface and core samples, were collected from 28 locations where past human activities would have minimal influence on contaminant distributions in soil. Cesium-137 activity was used as a means to assess whether samples were collected in undisturbed locations. The distribution of plutonium (as 239,240Pu) in soil was consistent with past sampling conducted by DOE, the Colorado Department of Public Health and Environment, and others. Elevated levels of 239,240Pu were found immediately east of the Rocky Flats Plant, with concentrations falling rapidly with distance from the plant to levels consistent with background from fallout. Samples collected in areas south, west, and north of the plant were generally consistent with background from fallout. No biases in past sampling due to choice of sampling locations or sampling methodology were evident. The study shows that local citizens, when provided sufficient resources, can design and implement technical studies that directly address community concerns where trust in the regulated community and/or regulators is low

  3. The Pöschl Teller model for total cross section of neutron scattering from 240Pu

    Neutron scattering cross-section of 240Pu have been investigated using an attractive potential. On applying the modified Pöschl-Teller model, the total cross-section of the n+240Pu in the energy range of 5-20 MeV have been calculated. It was compared with the available experimental data and evaluated data of JENDL-4.0, ENDF/B-VII.0 and CENDL-3.1 as well as with the theoretical values from TALYS-1.2 Nuclear Reaction Program, EMPIRE: 2.19 Nuclear Reaction Model Code and are found to be in reasonably good agreement. This supports the validity of the present calculation. (author)

  4. Prompt fission γ -ray spectrum characteristics from 240Pu(sf ) and 242Pu(sf )

    Oberstedt, S.; Oberstedt, A.; Gatera, A.; Göök, A.; Hambsch, F.-J.; Moens, A.; Sibbens, G.; Vanleeuw, D.; Vidali, M.

    2016-05-01

    In this paper we present first results for prompt fission γ -ray spectra (PFGS) characteristics from the spontaneous fission (sf) of 240Pu and 242Pu. For 242Pu(sf ) we obtained, after proper unfolding of the detector response, an average energy per photon ɛ¯γ=(0.843 ±0.012 ) MeV, an average multiplicity M¯γ=(6.72 ±0.07 ) , and an average total γ -ray energy release per fission E¯γ ,tot = (5.66 ± 0.06) MeV. The 240Pu(sf ) emission spectrum was obtained by applying a so-called detector-response transformation function determined from the 242Pu spectrum measured in exactly the same geometry. The results are an average energy per photon ɛ¯γ=(0.80 ±0.07 ) MeV, the average multiplicity M¯γ = (8.2 ± 0.4), and an average total γ -ray energy release per fission E¯γ ,tot = (6.6 ± 0.5) MeV. The PFGS characteristics for 242Pu(sf ) are in very good agreement with those from thermal-neutron-induced fission on 241Pu and scales well with the corresponding prompt neutron multiplicity. Our results in the case of 240Pu(sf ), although drawn from a limited number of events, show a significantly enhanced average multiplicity and average total energy, but may be understood from a different fragment yield distribution in 240Pu(sf ) compared to that of 242Pu(sf ).

  5. Background distributions of 239+240Pu and 137Cs of upland soil in Rokkasho, Japan

    The background distributions of Pu and 137Cs in soil were investigated in Rokkasho, Aomori Prefecture, where the first commercial nuclear fuel reprocessing plant in Japan is now being constructed. Soil core samples to 1 m depth were collected at 13 upland fields in Rokkasho and control sites in Hachinohe and Hirosaki. Since fields under yam (Dioscorea babatus) cultivation, which is a common crop in Rokkasho, were dug to approximately 1 m depth at harvesting, depth profiles of fallout radionuclides are heavily disturbed for most fields in Rokkasho. The mean inventories of 239+240Pu and 137Cs in three fields with no yam cultivation history were 116 Bq m-2 and 3.4 kBq m-2, respectively and similar to values in Hachinohe. However, the inventories were approximately a half of those in Hirosaki. The mean ratio of 239Pu/240Pu for all studied fields was 0.18±0.04, and similar to that of global fallout. The Pu concentrations correlate very well with 137Cs (r=0.97) in spite of heavy disturbance of soil, and the ratio of 239+240Pu/137Cs was 0.037±0.007, which is a typical value for global fallout. (author)

  6. 239 240Pu in Lake Michigan: 1971 to 1978

    The plutonium concentration data presented previously have consisted primarily of results from studies of short-term variations, i.e., the annual plutonium cycle conducted at Lake Michigan station ANL-5, 12 km SW of Grand Haven, Michigan. In this report, mean annual concentrations of total plutonium in unfiltered water from far off-shore (> 30 km) stations for the period 1971 through 1977, and from station ANL-5 (1975 through 1978) are summarized to establish the long-term trend in plutonium concentration in Lake Michigan. The results presented show that the mean annual concentration in the water column is similar at ANL-5 and at offshore stations and has decreased at the rate of only 6% per year during the period 1972 through 1978. The nearly constant concentration indicates that steady-state equilibria exist between plutonium inputs to the lake and the loss of plutonium from the water column. Observations suggest the existence of an active redox cycle for Pu in Lake Michigan. In this cycle, Pu IV atoms in solution are continually taken up by particulate materials but may be oxidized within microzones of the particles such as freshly deposited manganese coatings and also in solution by agents such as dissolved oxygen. In turn, the concentration of Pu VI in solution may be limited by reaction with reducing constituents of the coloidal-sized fraction (or decomposer organisms such as bacteria or fungi, which might have been present after filtration) and with planktonic organisms in the environment to produce Pu IV and thus maintain the cycle

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

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

  8. The coagulation of dissolved sup(239,240)Pu in estuaries as determined from a mixing experiment

    A mixing experiment, using large volumes (100 l) of filtered (240Pu during estuarine mixing. An organic-rich freshwater with a relatively high concentration (0.8 dpm/100 l) of dissolved sup(239,) 240Pu was used as one end-member; Buzzards Bay seawater (dissolved sup(239,) 240Pu=0.04 dpm/100 l) was the other. The results demonstrate that dissolved sup(239,) 240Pu in the freshwater undergoes extensive and rapid coagulation under simulated estuarine conditions. There is a strong correlation between the amount of coagulation of dissolved sup(239,) 240Pu, humic acids (HA), and Fe. The extent of coagulation of all three constituents increases with increasing salinity and the net extent of their removal is 53%, 57%, and 100% for Pu, HA, and Fe respectively. As has been domented for Fe in freshwater, dissolved sup(239,) 240Pu appears to be stabilized by naturally occurring humic substances to form negatively charged colloids which are then coagulated by seawater cations. The extrapolation of these experimental results to real estuaries will require additonal research. (orig.)

  9. Measurement of the 240Pu/239Pu mass ratio using a transition-edge-sensor microcalorimeter for total decay energy spectroscopy.

    Hoover, Andrew S; Bond, Evelyn M; Croce, Mark P; Holesinger, Terry G; Kunde, Gerd J; Rabin, Michael W; Wolfsberg, Laura E; Bennett, Douglas A; Hays-Wehle, James P; Schmidt, Dan R; Swetz, Daniel; Ullom, Joel N

    2015-04-01

    We have developed a new category of sensor for measurement of the (240)Pu/(239)Pu mass ratio from aqueous solution samples with advantages over existing methods. Aqueous solution plutonium samples were evaporated and encapsulated inside of a gold foil absorber, and a superconducting transition-edge-sensor microcalorimeter detector was used to measure the total reaction energy (Q-value) of nuclear decays via heat generated when the energy is thermalized. Since all of the decay energy is contained in the absorber, we measure a single spectral peak for each isotope, resulting in a simple spectral analysis problem with minimal peak overlap. We found that mechanical kneading of the absorber dramatically improves spectral quality by reducing the size of radioactive inclusions within the absorber to scales below 50 nm such that decay products primarily interact with atoms of the host material. Due to the low noise performance of the microcalorimeter detector, energy resolution values of 1 keV fwhm (full width at half-maximum) at 5.5 MeV have been achieved, an order of magnitude improvement over α-spectroscopy with conventional silicon detectors. We measured the (240)Pu/(239)Pu mass ratio of two samples and confirmed the results by comparison to mass spectrometry values. These results have implications for future measurements of trace samples of nuclear material. PMID:25723106

  10. Microscopic modeling of mass and charge distributions in the spontaneous fission of 240Pu

    Sadhukhan, Jhilam; Schunck, Nicolas

    2016-01-01

    In this letter, we outline a methodology to calculate microscopically mass and charge distributions of spontaneous fission yields. We combine the multi-dimensional minimization of collective action for fission with stochastic Langevin dynamics to track the relevant fission paths from the ground-state configuration up to scission. The nuclear potential energy and collective inertia governing the tunneling motion are obtained with nuclear density functional theory in the collective space of shape deformations and pairing. We obtain a quantitative agreement with experimental data and find that both the charge and mass distributions in the spontaneous fission of 240Pu are sensitive both to the dissipation in collective motion and to adiabatic characteristics.

  11. Microscopic modeling of mass and charge distributions in the spontaneous fission of 240Pu

    Sadhukhan, Jhilam; Nazarewicz, Witold; Schunck, Nicolas

    2016-01-01

    We propose a methodology to calculate microscopically the mass and charge distributions of spontaneous fission yields. We combine the multidimensional minimization of collective action for fission with stochastic Langevin dynamics to track the relevant fission paths from the ground-state configuration up to scission. The nuclear potential energy and collective inertia governing the tunneling motion are obtained with nuclear density functional theory in the collective space of shape deformations and pairing. We obtain a quantitative agreement with experimental data and find that both the charge and mass distributions in the spontaneous fission of 240Pu are sensitive both to the dissipation in collective motion and to adiabatic fission characteristics.

  12. {sup 239+240}Pu in the Barents Sea Regions. Sources and radioecological assessment

    Iosjpe, Mikhail [Norwegian Radiation Protection Authority, P.O. Box 55, N-1332 Oesteraas (Norway)

    2014-07-01

    The radioecological assessment for {sup 239+240}Pu in the Barents sea regions was made using the compartment modelling approach. The following sources of radioactive contamination were under consideration: global fallout from atmospheric testing of nuclear weapons, transport of {sup 239+240}Pu from the Sellafield and La Hauge nuclear plants and underwater testing of nuclear weapons in Chernaya Bay, Novaya Zemlya. The box model developed at NRPA uses a modified approach for compartmental modeling, which takes into account the dispersion of radionuclides over time. The box structures for surface, mid-depth and deep water layers have been developed based on the description of polar, Atlantic and deep waters in the Arctic Ocean and the Northern Seas, as well as site-specific information for the boxes. The volume of the three water layers in each box has been calculated using detailed bathymetry together with Geographical Information Systems. The box model includes the processes of advection of radioactivity between compartments, sedimentation, diffusion of radioactivity through pore water in sediments, resuspension, mixing due to bioturbation, particle mixing and a burial process for radionuclides in deep sediment layers. Radioactive decay is calculated for all compartments. The contamination of biota is further calculated from the known radionuclide concentrations in filtered seawater in the different water regions. Doses to man are calculated on the basis of seafood consumptions, in accordance with available data for seafood catches and assumptions about human diet in the respective areas. Dose to biota are determined on the basis of calculated radionuclide concentrations in marine organisms, water and sediment, using dose conversion factors. Results of the calculations show that atmospheric deposition is the dominant source for the Barents Sea, except for the Chernaya Bay region. It is also demonstrated that the impact of the Sellafield nuclear facilities has

  13. Annular cylinders experimental programme containing plutonium solutions at different 240Pu contents

    From 1963 to 1976, 730 critical experiments dealing with annular cylinders containing plutonium nitrate solutions were conducted on Valduc critical facility, called 'Apparatus B'. They aimed at validating critical configurations encountered in the fuel cycle, especially in storage and also at validating the 240Pu cross-sections in thermal neutron spectrum. It is to be noticed that these experiments validate criticality codes either in configurations with reactor-grade plutonium coming from the reprocessing cycle or with weapon-grade plutonium coming from the decommissioning of nuclear weapons. (authors)

  14. Application of 210Pb geochronology by the reconstruction of historical radionuclides concentrations ( 137Cs et 239+240Pu ) in the columns of the Alboran Sea

    Full text: The marine sediments are considered as a final reservoir of radioactive contaminants. The 210Pb from atmospheric fallouts deposits is stored in sediments with those from 226Ra original lithogenic. The activity of 210Pb excess in the accumulated sediment is an important tool to study the chronological process of sedimentation on recent time scales at over 100 years. However, this method should be validated using at least one independent tracer which provides an unequivocal temporal marker as 137Cs from nuclear testing. This work presents a method to rebuild historic concentrations of 137Cs and 230+240Pu in the water column Alboran Sea and their corresponding stream sediment. This is achieved by coupling the radiometric dating of the sediment column profiles using three independent levels: the excess 210Pb, 137Cs and 239 +240Pu. On the other hand, a simple model of the water column has been adapted to this end by making use of atmospheric flow, the measured values of distribution coefficient (Kd) and a first approximation of the rate of sedimentation. The timing model CM-CSR (diffusion coefficient of sedimentation rate constant) has been successfully applied to the three independent profiles, and was able to determine the parameters of diffusion and mass sedimentation rate. The results obtained give some ideas on the fate of atmospheric inputs to the marine environment and, particularly, that of the Chernobyl accident. The results of the models showed that direct and deferred contributions of Chernobyl accident are negligible in the Alboran Sea. The annual input of 210Pb to the sediment was estimated at 720±150 Bq.m-2. by year, while the rate of sedimentation is about 0092±0.003 g.cm-2 by year. On the other hand, the model could successfully reconstruct historic concentrations of 137Cs and 239+240Pu in the water column, and was able to reproduce the work of the same elements in the sediment column

  15. Transuranic concentrations in reef and pelagic fish from the Marshall Islands. [/sup 239/Pu, /sup 240/Pu

    Noshkin, V.E.; Eagle, R.J.; Wong, K.M.; Jokela, T.A.

    1980-09-01

    Concentrations of /sup 239 + 240/Pu are reported in tissues of several species of reef and pelagic fish caught at 14 different atolls in the northern Marshall Islands. Several regularities that are species dependent are evident in the distribution of /sup 239 + 240/Pu among different body tissues. Concentrations in liver always exceeded those in bone and concentrations were lowest in the muscle of all fish analyzed. A progressive discrimination against /sup 239 + 240/Pu was observed at successive trophic levels at all atolls except Bikini and Enewetak, where it was difficult to conclude if any real difference exists between the average concentration factor for /sup 239 + 240/Pu among all fish, which include bottom feeding and grazing herbivores, bottom feeding carnivores, and pelagic carnivores from different atoll locations. The average concentration of /sup 239 + 240/Pu in the muscle of surgeonfish from Bikini and Enewetak was not significantly different from the average concentrations determined in these fish at the other, lesser contaminated atolls. Concentrations among all 3rd, 4th, and 5th trophic level species are highest at Bikini where higher environmental concentrations are found. The reasons for the anomalously low concentrations in herbivores from Bikini and Enewetak are not known.

  16. Alpha-particle emission probabilities in the decay of {sup 240}Pu

    Sibbens, G., E-mail: goedele.sibbens@ec.europa.e [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Pomme, S.; Altzitzoglou, T. [European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel (Belgium); Garcia-Torano, E. [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Janssen, H.; Dersch, R.; Ott, O. [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany); Martin Sanchez, A. [Departamento de Fisica, Universidad de Extremadura, Badajoz, E-06071 (Spain); Rubio Montero, M.P. [Departamento de Fisica Aplicada, Universidad de Extremadura, Merida, Badajoz, E-06800 (Spain); Loidl, M. [Laboratoire National Henri Becquerel, LNE/CEA-LIST, 91191 Gif-sur-Yvette (France); Coron, N.; Marcillac, P. de [Institut d' Astrophysique Spatiale, CNRS, 91405 Orsay Campus (France); Semkow, T.M. [Wadsworth Center, New York State Department of Health, Albany, NY 12201 (United States)

    2010-07-15

    Sources of enriched {sup 240}Pu were prepared by vacuum evaporation on quartz substrates. High-resolution alpha-particle spectrometry of {sup 240}Pu was performed with high statistical accuracy using silicon detectors and with low statistical accuracy using a bolometer. The alpha-particle emission probabilities of six transitions were derived from the spectra and compared with literature values. Additionally, some alpha-particle emission probabilities were derived from {gamma}-ray intensity measurements with a high-purity germanium detector. The alpha-particle emission probabilities of the three main transitions at 5168.1, 5123.6 and 5021.2 keV were derived from seven aggregate spectra analysed with five different fit functions and the results were compatible with evaluated data. Two additional weak peaks at 4863.5 and 4492.0 keV were fitted separately, using the exponential of a polynomial function to represent the underlying tailing of the larger peaks. The peak at 4655 keV could not be detected by alpha-particle spectrometry, while {gamma}-ray spectrometry confirms that its intensity is much lower than expected from literature.

  17. Induced Fission of 240Pu within a Real-Time Microscopic Framework

    Bulgac, Aurel; Magierski, Piotr; Roche, Kenneth J.; Stetcu, Ionel

    2016-03-01

    We describe the fissioning dynamics of 240Pu from a configuration in the proximity of the outer fission barrier to full scission and the formation of the fragments within an implementation of density functional theory extended to superfluid systems and real-time dynamics. The fission fragments emerge with properties similar to those determined experimentally, while the fission dynamics appears to be quite complex, with many excited shape and pairing modes. The evolution is found to be much slower than previously expected, and the ultimate role of the collective inertia is found to be negligible in this fully nonadiabatic treatment of nuclear dynamics, where all collective degrees of freedom (CDOF) are included (unlike adiabatic treatments with a small number of CDOF).

  18. ZPR-6 assembly 7 high {sup 240}Pu core experiments : a fast reactor core with mixed (Pu,U)-oxide fuel and a centeral high{sup 240}Pu zone.

    Lell, R. M.; Morman, J. A.; Schaefer, R.W.; McKnight, R.D.; Nuclear Engineering Division

    2009-02-23

    ZPR-6 Assembly 7 (ZPR-6/7) encompasses a series of experiments performed at the ZPR-6 facility at Argonne National Laboratory in 1970 and 1971 as part of the Demonstration Reactor Benchmark Program (Reference 1). Assembly 7 simulated a large sodium-cooled LMFBR with mixed oxide fuel, depleted uranium radial and axial blankets, and a core H/D near unity. ZPR-6/7 was designed to test fast reactor physics data and methods, so configurations in the Assembly 7 program were as simple as possible in terms of geometry and composition. ZPR-6/7 had a very uniform core assembled from small plates of depleted uranium, sodium, iron oxide, U{sub 3}O{sub 8} and Pu-U-Mo alloy loaded into stainless steel drawers. The steel drawers were placed in square stainless steel tubes in the two halves of a split table machine. ZPR-6/7 had a simple, symmetric core unit cell whose neutronic characteristics were dominated by plutonium and {sup 238}U. The core was surrounded by thick radial and axial regions of depleted uranium to simulate radial and axial blankets and to isolate the core from the surrounding room. The ZPR-6/7 program encompassed 139 separate core loadings which include the initial approach to critical and all subsequent core loading changes required to perform specific experiments and measurements. In this context a loading refers to a particular configuration of fueled drawers, radial blanket drawers and experimental equipment (if present) in the matrix of steel tubes. Two principal core configurations were established. The uniform core (Loadings 1-84) had a relatively uniform core composition. The high {sup 240}Pu core (Loadings 85-139) was a variant on the uniform core. The plutonium in the Pu-U-Mo fuel plates in the uniform core contains 11% {sup 240}Pu. In the high {sup 240}Pu core, all Pu-U-Mo plates in the inner core region (central 61 matrix locations per half of the split table machine) were replaced by Pu-U-Mo plates containing 27% {sup 240}Pu in the plutonium

  19. Feedback on 239Pu and 240Pu nuclear data and associated covariances through the CERES integral experiments

    Benchmark measurements of irradiated and un-irradiated fuel samples were performed in the framework of the CERES collaborative program between AEA (UK Atomic Energy Agency) and CEA (French Atomic Energy Commission). These experiments provide relevant data for the validation of fuel burn-up and criticality-safety calculations for the whole fuel cycle. As part of this program, pile-oscillation measurements were carried out on a range of mixed-oxide samples with plutonium of various mass and isotopic contents, both in the MINERVE and DIMPLE reactors. Four core configurations, two over-thermalized situations and two pressurized water reactor (PWR)-type situations, were constituted with different forward and adjoint flux spectra, emphasizing fission and/or capture contributions. The experiments were analyzed using reference TRIPOLI4 calculations with the JEFF-3.1.1 library, using exact three-dimensional models of the core configurations. In a first step, calculations of each DIMPLE configuration were performed and compared with the experiment, showing very good agreements with a maximum C-E of -230 pcm. In the second step, reactivity worth experiments were analyzed, using recently developed exact-perturbation capabilities in TRIPOLI4. A consistent assimilation of calculation over experiment discrepancies was performed with the CONRAD code, using the integral data assimilation method. Covariance matrix on multigroup neutron cross sections and multiplicities were generated and significant trends were identified, especially on the 239Pu and 240Pu capture cross sections in the thermal energy range (E < 0.1 eV). Further investigations should be required to confirm these conclusions, due to the strong dependence of these trends and of posterior covariances to prior covariances. (author)

  20. Suitability of 239+240Pu and 137Cs as tracers for soil erosion assessment in mountain grasslands.

    Alewell, Christine; Meusburger, Katrin; Juretzko, Gregor; Mabit, Lionel; Ketterer, Michael E

    2014-05-01

    Anthropogenic radionuclides have been distributed globally due to nuclear weapons testing, nuclear accidents, nuclear weapons fabrication, and nuclear fuel reprocessing. While the negative consequences of this radioactive contamination are self-evident, the ubiquitous fallout radionuclides (FRNs) distribution form the basis for the use as tracers in ecological studies, namely for soil erosion assessment. Soil erosion is a major threat to mountain ecosystems worldwide. We compare the suitability of the anthropogenic FRNs, 137Cs and 239+240Pu as soil erosion tracers in two alpine valleys of Switzerland (Urseren Valley, Canton Uri, Central Swiss Alps and Val Piora, Ticino, Southern Alps). We sampled reference and potentially erosive sites in transects along both valleys. 137Cs measurements of soil samples were performed with a Li-drifted Germanium detector and 239+240Pu with ICP-MS. Our data indicates a heterogeneous deposition of the 137Cs, since most of the fallout origins from the Chernobyl April/May 1986 accident, when large parts of the European Alps were still snow-covered. In contrast, 239+240Pu fallout originated mainly from 1950s to 1960s atmospheric nuclear weapons tests, resulting in a more homogenous distribution and thus seems to be a more suitable tracer in mountainous grasslands. Soil erosion assessment using 239+240Pu as a tracer pointed to a huge dynamic and high heterogeneity of erosive processes (between sedimentation of 1.9 and 7 t ha(-1) yr(-1) and erosion of 0.2-16.4 t ha(-1) yr(-1) in the Urseren Valley and sedimentation of 0.4-20.3 t ha(-1) yr(-1) and erosion of 0.1-16.4 t ha(-1) yr(-1) at Val Piora). Our study represents a novel and successful application of 239+240Pu as a tracer of soil erosion in a mountain environment. PMID:24374184

  1. Retention and translocation of foliar applied {sup 239,240}Pu and {sup 241}Am, as compared to {sup 137}Cs and {sup 85}Sr, into bean plants (Phaseolus vulgaris)

    Henner, P. [Institute for Radioprotection and Nuclear Safety, Environment and Emergency Operations Division, Department for the Study of Radionuclides Behaviour in Ecosystems, Laboratory of Radioecology and Ecotoxicology, IRSN/DPRE/SECRE/LRE, Cadarache Centre, Building 186, BP 3, 13115 Saint-Paul-lez-Durance (France)]. E-mail: pascale.henner@irsn.fr; Colle, C. [Institute for Radioprotection and Nuclear Safety, Environment and Emergency Operations Division, Department for the Study of Radionuclides Behaviour in Ecosystems, Laboratory of Radioecology and Ecotoxicology, IRSN/DPRE/SECRE/LRE, Cadarache Centre, Building 186, BP 3, 13115 Saint-Paul-lez-Durance (France); Morello, M. [Institute for Radioprotection and Nuclear Safety, Environment and Emergency Operations Division, Department for the Study of Radionuclides Behaviour in Ecosystems, Laboratory of Radioecology and Ecotoxicology, IRSN/DPRE/SECRE/LRE, Cadarache Centre, Building 186, BP 3, 13115 Saint-Paul-lez-Durance (France)

    2005-07-01

    Foliar transfer of {sup 241}Am, {sup 239,240}Pu, {sup 137}Cs and {sup 85}Sr was evaluated after contamination of bean plants (Phaseolus vulgaris) at the flowering development stage, by soaking their first two trifoliate leaves into contaminated solutions. Initial retentions of {sup 241}Am (27%) and {sup 239,240}Pu (37%) were higher than those of {sup 137}Cs and {sup 85}Sr (10-15%). Mean fraction of retained activity redistributed among bean organs was higher for {sup 137}Cs (20.3%) than for {sup 239,240}Pu (2.2%), {sup 241}Am (1%) or {sup 85}Sr (0.1%). Mean leaf-to-pod translocation factors (Bq kg{sup -1}dry weight pod/Bq kg{sup -1}dry weight contaminated leaves) were 5.0 x 10{sup -4} for {sup 241}Am, 2.7 x 10{sup -6} for {sup 239,240}Pu, 5.4 x 10{sup -2} for {sup 137}Cs and 3.6 x 10{sup -4} for {sup 85}Sr. Caesium was mainly recovered in pods (12.8%). Americium and strontium were uniformly redistributed among leaves, stems and pods. Plutonium showed preferential redistribution in oldest bean organs, leaves and stems, and very little redistribution in forming pods. Results for americium and plutonium were compared to those of strontium and caesium to evaluate the consistency of the attribution of behaviour of strontium to transuranium elements towards foliar transfer, based on translocation factors, as stated in two radioecological models, ECOSYS-87 and ASTRAL.

  2. 90Sr and 239+240Pu 238Pu 241Am in some samples of mushrooms and forest soil from Poland

    Strontium-90, plutonium and americium activity concentrations in a few samples of forest soils, some species of mushrooms and fern leaves have been determined. These results are compared with cesium activity concentrations in the same materials obtained in a previous work. Radiochemical procedures are described. The origin of the contamination (Chernobyl accident or nuclear test explosion release) is discussed. The 90Sr activity concentration ranges from 0.6 Bq/kg (mushroom samples) to 48.4 Bq/kg (fern leaves). For 239+240Pu, it ranges from not detected above background (mushrooms, fern) to 10.8 Bq/kg (humus layer of forest soil). The maximum concentration of 241Am is found to be 2.4 Bq/kg (humus sample) and for 238Pu it is 0.85 Bq/kg (also in the humus sample). (author) 16 refs.; 7 figs.; 3 tabs

  3. Results of 90Sr and 239+240Pu, 238Pu, 241Am measurements in some samples of mushrooms and forest soil from Poland

    Strontium-90, plutonium and americium activity concentrations in a few samples of forest soils, some species of mushrooms and fern leaves were determined. These results are compared with caesium activity concentrations in the same materials obtained in a previous work. Radiochemical procedures are described. The origin of the contamination (Chernobyl accident or nuclear test explosion release) is discussed. The 90Sr activity concentration ranges from 0.6 Bq/kg (mushroom samples) to 48.4 Bq/kg (fern leaves). For 239+240Pu, it ranges from not detected above background (mushrooms, fern) to 10.8 Bq/kg (humus layer of forest soil). The maximum concentration of 241Am is found to be 2.4 Bq/kg (humus sample) and for 238Pu it is 0.85 Bq/kg (also in the humus sample). (author). 12 refs, 9 figs, 7 tabs

  4. Role of natural organic matter on iodine and (239)(,240)Pu distribution and mobility in environmental samples from the northwestern Fukushima Prefecture, Japan.

    Xu, Chen; Zhang, Saijin; Sugiyama, Yuko; Ohte, Nobuhito; Ho, Yi-Fang; Fujitake, Nobuhide; Kaplan, Daniel I; Yeager, Chris M; Schwehr, Kathleen; Santschi, Peter H

    2016-03-01

    been completely converted to organo-iodine. Fukushima-derived (239,240)Pu was detectable at a distance ∼ 61 km away, NW of FDNPP. However, it is confined to the litter layer, even three years after the FDNPP accident-derived emissions. Plutonium-239,240 activities were significantly correlated with soil OC and nitrogen contents, indicating Pu may be associated with nitrogen-containing SOM, similar to what has been observed at other locations in the United States. Together, these finding suggest that natural organic matter (NOM) plays a key role in affecting the fate and transport of I and Pu and may warrant greater consideration for predicting long-term stewardship of contaminated areas and evaluating various remediation options in Japan. PMID:26773510

  5. Determination of plutonium isotopes in freshwater lake sediments by sector-field ICP-MS after separation using ion-exchange chromatography

    The determination of Pu isotopes in lake sediments is important for many studies, such as Pu pollution source identification, sediment mixing estimation, erosion evaluation and establishment of deposition chronology in lakes. In this paper, a simple analytical method using sector field inductively coupled plasma mass spectrometry (ICP-MS) combined with two-stage chromatographic separation and purification of Pu was developed based on the optimization and adaptation of the previously published method for marine samples with an emphasis on the study of the elimination of interferences for the analysis of freshwater lake sediments. A strong base anion-exchange resin (AG MP-1M) was used to purify Pu isotopes with concentrated HBr as the final eluent for Pu elution. The chemical yields were ca. 64% and the decontamination factor for U was ca. 105. The developed method was validated using a freshwater lake sediment reference material (SRM-4354) and a marine sediment reference material (IAEA-368), and applied to the determination of Pu isotopes in sediment samples of Lake Poyang, East China. For the analysis of certified reference materials, both 239+240Pu activity of 31.6 mBq g-1 and 240Pu/239Pu atom ratio of 0.033 for IAEA-368 were comparable to the certified value and/or literature values. As for SRM-4354, 239+240Pu activity of 3.90 mBq g-1 agreed well with the certified value. However, the mean 240Pu/239Pu atom ratio of 0.144 was lower than those reported by other laboratories. This difference suggested that this material may be isotopically inhomogeneous. 240Pu/239Pu atom ratios of Poyang Lake sediment samples ranged from 0.185 to 0.192 with a mean value of 0.187±0.004, indicating that plutonium pollution originated from global fallout

  6. Evaluation of the fission and capture cross sections of 240Pu and 241Pu for ENDF/B-V

    Since there were appreciable new data which were not available for ENDF/B-IV, new evaluations for 240Pu and 241Pu were carried out for ENDF/B-V. The evaluation of the fission and capture cross sections is reviewed and problem areas are discussed. The neutron energy range of concern was from 10-5 eV to 20 MeV. Significant changes were made over the entire neutron energy region because of the new experimental data available. The problems in the evaluations due to discrepancies in the nuclear data are emphasized, particularly the 1-eV resonance in 240Pu and the 0.3-eV resonance in 241Pu. The evaluation of the fission and capture cross sections for ENDF/B-V represents an improvement over the previous evaluation; however, there continues to be a need for accurate experimental data. 7 figures

  7. Comparison of evaluations for 235U, 239Pu, 240Pu, 241Pu and 242Pu with integral measurements

    The evaluations for 235U, 239Pu, 240Pu, 241Pu and 242Pu are considered. Intercomparison is made of the neutron cross section data from INDL/A, ENDL-84, ENDF/B-5 and ENDF/B-6 (where applicable). Integral measurements of the spectrum averaged cross sections are compared to the values derived from evaluated data libraries. (author). 40 refs, 49 figs, 11 tabs

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

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

    1997-05-01

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

  9. Numerical simulation of 137Cs and 239,240Pu concentrations by an ocean general circulation model

    We simulated the spatial distributions and the temporal variations of 137Cs and 239,240Pu concentrations in the ocean by using the ocean general circulation model which was developed by National Center of Atmospheric Research. These nuclides are introduced into seawaters from global fallout due to atmospheric nuclear weapons tests. The distribution of radioactive deposition on the world ocean is estimated from global precipitation data and observed values of annual deposition of radionuclides at the Meteorological Research Institute in Japan and several observed points in New Zealand. Radionuclides from global fallout have been transported by advection, diffusion and scavenging, and this concentration reduces by radioactive decay in the ocean. We verified the results of the model calculations by comparing simulated values of 137Cs and 239,240Pu in seawater with the observed values included in the Historical Artificial Radionuclides in the HAM database, which has been constructed by the Meteorological Research Institute. The vertical distributions of the calculated 137Cs concentrations were in good agreement and are in good agreement with the observed profiles in the 1960s up to 250 m, in the 1970s up to 500 m, in the 1980s up to 750 m and in the 1990s up to 750 m. However, the calculated 137Cs concentrations were underestimated compared with the observed 137Cs at the deeper layer. This may suggest other transport processes of 137Cs to deep waters. The horizontal distributions of 137Cs concentrations in surface water could be simulated. A numerical tracer release experiment was performed to explain the horizontal distribution pattern. A maximum 239,240Pu concentration layer occurs at an intermediate depth for both observed and calculated values, which is formed by particle scavenging. The horizontal distributions of the calculated 239,240Pu concentrations in surface water could be simulated by considering the scavenging effect

  10. Impact of environmental curium on plutonium migration and isotopic signatures.

    Kurosaki, Hiromu; Kaplan, Daniel I; Clark, Sue B

    2014-12-01

    Plutonium (Pu), americium (Am), and curium (Cm) activities were measured in sediments from a former radioactive waste disposal basin located on the Savannah River Site, South Carolina, and in subsurface aquifer sediments collected downgradient from the basin. In situ Kd values (Pu concentration ratio of sediment/groundwater) derived from this field data and previously reported groundwater concentration data compared well to laboratory Kd values reported in the literature. Pu isotopic signatures confirmed multiple sources of Pu contamination. The ratio of (240)Pu/(239)Pu was appreciably lower for sediment samples compared to the associated groundwater. This isotopic ratio difference may be explained by the following: (1) (240)Pu produced by decay of (244)Cm may exist predominantly in high oxidation states (Pu(V)O2(+) and Pu(VI)O2(2+)) compared to Pu derived from the disposed waste effluents, and (2) oxidized forms of Pu sorb less to sediments than reduced forms of Pu. Isotope-specific Kd values calculated from measured Pu activities in the sediments and groundwater indicated that (240)Pu, which is derived primarily from the decay of (244)Cm, had a value of 10 ± 2 mL g(-1), whereas (239)Pu originating from the waste effluents discharged at the site had a value of 101 ± 8 mL g(-1). One possible explanation for the isotope-specific sorption behavior is that (240)Pu likely existed in the weaker sorbing oxidation states, +5 or +6, than (239)Pu, which likely existed in the +3 or +4 oxidation states. Consequently, remediation strategies for radioactively contaminated systems must consider not only the discharged contaminants but also their decay products. In this case, mitigation of Cm as well as Pu will be required to completely address Pu migration from the source term. PMID:25350948

  11. Impact of soil humus material on the behaviour of 239+240Pu in the terrestrial environment in tropical conditions

    When long-lived radionuclides deposited by fallout come in contact with soil, most are bound so tightly to soil particles that they are nearly immobile. Many fallout radionuclides are held either by adsorption on reactive sites on clay mineral soil particles, or by ion exchange and precipitation as hydroxide or sulfide. Thus, the radionuclides are distributed in organic and inorganic constituents of soil. Natural organic matter of soil consists of the dead plant and animal material and partially decomposed and resynthesized organic compounds present in soils and sediments. The purpose of this study was to determine the association of 239,240Pu with natural organic substances in soils

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

    The environmental mobility and bioavailability of radionuclides are related to their physicochemical forms, namely species. We here present a speciation analysis of important radionuclides including 129I (also 127I), 137Cs, 232Th, 238U and plutonium isotopes (239Pu and 240Pu) in soil (IAEA-375) and sediment (NIST-4354) standard reference materials and two fresh sediment samples from Øvre Heimdalsvatnet Lake, Norway. A modified sequential extraction protocol was used for the speciation analysis of these samples to obtain fractionation information of target radionuclides. Analytical results reveal that the partitioning behaviour, and thus the potential mobility and bioavailability, are exclusively featured for the individual radionuclide. Iodine is relatively mobile and readily binds to organic matter, while plutonium is mainly bound to both organic matter and nitric acid leachable fractions. Thorium is predominated in nitric acid leachable fraction and caesium is primarily observed in nitric acid and aqua regia leachable fractions and residue. Our analytical results reveal that around 50% of uranium might still remain in the residue which could not be extracted with aggressive acid, namely, aqua regia.

  13. Routine radiochemical method for the determination of 90Sr, 238Pu, 239+240Pu, 241Am and 244Cm in environmental samples

    Routine analytical procedures have been developed for the reliable simultaneous determination of 90Sr, 238Pu, 239+240Pu, 241Am and 242-244Cm, Chernobyl derived radioisotopes and fallout after nuclear weapon tests in a wide range of environmental samples: soil (100-200 g), sediments, aerosols, water and vegetation. This procedure has been applied to thousands of soil and sediment samples and hundreds of biological and water samples taken in the exclusive zone of Chernobyl NPP and different regions of Ukraine from 1989 to the present. After the sample has been properly prepared and isotopic tracers added, plutonium, americium and curium are precipitated with calcium oxalate and then lanthanum fluoride. Plutonium is separated from americium and curium by anion-exchange. Americium and curium are separated from rare earths by cation-exchange with gradient elute α-hydroxy-iso-butyric acid. During projects by AQCS IAEA 'Evaluation of Methods for 90Sr in a Mineral Matrix' and 'Proficiency Test for 239Pu, 241Pu and 241Am Measurement in a Mineral Matrix' accuracy and precision for 90Sr, 239Pu and 241Am by present procedure was evaluated. Advantages, difficulties and limitations of the method are discussed. (author)

  14. Migration of 137Cs, 90Sr, and 239+240Pu in Mediterranean forests: influence of bioavailability and association with organic acids in soil

    The understanding of downward migration of anthropogenic radionuclides in soil is a key factor in the assessment of their environmental behavior. There are several factors that can affect this process, such as the radionuclide source, their chemical form, soil and environmental characteristics, etc. Two Mediterranean pinewood ecosystems in Spain, which were affected mainly by global fallout, were selected to assess the migration of 137Cs, 90Sr, and 239+240Pu. Using auxiliary modeling (diffusion–convection equation and compartmental model), it followed from field observations that the migration velocities of 90Sr and 239+240Pu were similar and higher than that of 137Cs. The downward migration of radionuclides can be considered a consequence of their association with soil particles. A sequential speciation procedure also confirmed that 90Sr was the most bioavailable radionuclide followed by 239+240Pu and 137Cs. Although this can explain the different velocity of 90Sr and 137Cs, bioavailability could not explain by itself the similar velocities of 239+240Pu and 90Sr. The presence of organic acids in the soil can also influence the migration of radionuclides attached to them, which decreased in the order: 239+240Pu > 90Sr > 137Cs. Thus, the joint consideration of bioavailable and humic + fulvic acid fractions can explain the observed differences in the downward velocities. - Highlights: • Downward migration velocities of 137Cs, 90Sr and 239+240Pu in two Mediterranean forests were determined. • Downward migration velocities: 90Sr ≈ 239+240Pu > 137Cs. • Bioavailability by itself (90Sr > 239+240Pu > 137Cs) does not explain differences in migration velocities. • Humic + Fulvic acids: 239+240Pu > 90Sr > 137Cs. • Humic + Fulvic acids and bioavailable fraction can explain the downward migration velocities

  15. A modelling study on {sup 137}Cs and {sup 239,240}Pu behaviour in the Alboran Sea, western Mediterranean

    Perianez, R. [Departamento Fisica Aplicada I, E.U. Ingenieria Tecnica Agricola, Universidad de Sevilla, Ctra., Utrera km 1, 41013 Sevilla (Spain)], E-mail: rperianez@us.es

    2008-04-15

    A model for simulating the dispersion processes of {sup 137}Cs and {sup 239,240}Pu in the Alboran Sea is described. The model consists of two hydrodynamic models: a 2D depth-averaged model and a two-layer model which provide tidal and geostrophic currents, respectively; a sediment transport model which provides suspended particle concentrations and sedimentation rates over the domain; and the radionuclide dispersion model including interactions of dissolved radionuclides with suspended particles and bed sediments. These processes are formulated using kinetic transfer coefficients. The hydrodynamic and sediment models are run and validated in advance, and their results are then used to simulate the dispersion of {sup 137}Cs and {sup 239,240}Pu, which are introduced from atmospheric fallout. Radionuclide concentrations in the water column and distributions in bed sediments have been compared with measurements in the sea. Both set of data are, in general, in agreement. The model has also been applied to calculate radionuclide fluxes through the Strait of Gibraltar. These computed fluxes have been compared with previous estimations as well.

  16. Calculated activities of some isotopes in the RA reactor highly enriched fuel significant for possible environmental contamination - Operational report

    This report contains calculation basis and obtained results of activities for three groups of isotopes in the RA reactor 80% enriched fuel element. The following isotopes are included: 1) 85mKr, 87Kr, 88Kr, 131J, 132J, 133J, 134J, 135J, 133Xe, 138Xe i 138Cs, 2) 89Sr, 90Sr, 91Sr, 92Sr, 95Zr, 97Zr, 103Ru, 105Ru, 106Ru, 129mTe, 134Cs, 137Cs, 140Ba, 144Ce, kao i 3) 238Pu, 239Pu i 240Pu. It was estimated that the fuel is exposed to mean neutron flux. The periodicity of reactor operation is taken into account. Calculation results are given dependent on the time of exposure. These results are to be used as source data for Ra reactor safety analyses

  17. References to Studies of 137Cs, 90Sr and 239+240Pu in the Pacific Ocean a Bibliography

    Noshkin, V.E.

    2001-02-01

    This report contains a listing of publications known to this author on reported concentrations, reviews and discussions of {sup 137}Cs, {sup 90}Sr and {sup 239+240}Pu in seawater, sediment and the biota from parts of the North and South Pacific Ocean. Each reference has been assigned an accession number consisting of the first three letters of the first author's last name followed by the first letter of the first name, the year of the publication and an assigned number. Studies in both the coastal areas and the open ocean are included as well as those providing data within lagoons of coral atolls. Some references to the radionuclides in the Indian Ocean are also provided.

  18. sup(239/240)Pu, 137Cs, 90Sr, and 40K in different types of honey

    Information on the concentration of radionuclides in honey is of interest because this foodstuff consumed worldwide could be a source of radionuclides to man. Besides that, honey is used as a bioindicator for several radionuclides because the bees forage for nectar, pollen or honeydew over a large area of landscape. In this connection, it is of special interest to know when, and, if so, to what extent the concentrations of radionuclides in the honey depend on the type of honey sampled by the bees. For this reason, we determined sup(239/240)Pu, 137Cs, 90Sr and 40K in three important types of honey produced in the F.R.G., namely in honey from flowers, from honeydew and from heather. The data obtained in this way was used also to investigate whether significant correlations exist between these radionuclides in the various honey samples. (author)

  19. Bioturbation depths, rates and processes in Massachusetts Bay sediments inferred from modeling of 210Pb and 239 + 240Pu profiles

    Crusius, John; Bothner, Michael H.; Sommerfield, Christopher K.

    2004-01-01

    Profiles of 210Pb and 239 + Pu from sediment cores collected throughout Massachusetts Bay (water depths of 36-192 m) are interpreted with the aid of a numerical sediment-mixing model to infer bioturbation depths, rates and processes. The nuclide data suggest extensive bioturbation to depths of 25-35 cm. Roughly half the cores have 210Pb and 239 + 240Pu profiles that decrease monotonically from the surface and are consistent with biodiffusive mixing. Bioturbation rates are reasonably well constrained by these profiles and vary from ~0.7 to ~40 cm2 yr-1. As a result of this extensive reworking, however, sediment ages cannot be accurately determined from these radionuclides and only upper limits on sedimentation rates (of ~0.3 cm yr-1) can be inferred. The other half of the radionuclide profiles are characterized by subsurface maxima in each nuclide, which cannot be reproduced by biodiffusive mixing models. A numerical model is used to demonstrate that mixing caused by organisms that feed at the sediment surface and defecate below the surface can cause the subsurface maxima, as suggested by previous work. The deep penetration depths of excess 210Pb and 239 + 240Pu suggest either that the organisms release material over a range of >15 cm depth or that biodiffusive mixing mediated by other organisms is occurring at depth. Additional constraints from surficial sediment 234Th data suggest that in this half of the cores, the vast majority of the present-day flux of recent, nuclide-bearing material to these core sites is transported over a timescale of a month or more to a depth of a few centimeters below the sediment surface. As a consequence of the complex mixing processes, surface sediments include material spanning a range of ages and will not accurately record recent changes in contaminant deposition.

  20. Variation of activity levels, isotope ratios, concentration factors in space and time of plutonium in seaweed and mollusc species along the coast of the English Channel

    A study was carried out on the spatial and temporal variation of plutonium isotopes (238PU, 239-240Pu) in bio-indicator species (Fucus serratus, Patella sp., Mytilus edulis) sampled along the coast of the English Channel. Several periods of time were considered, covering 1982-1983, 1990-1993 and the year 1996. The activity levels of the radionuclides in question were less than 1 Bq kg-1 dry basis. A decrease in these activities has been observed over a number of years in relation to a reduction in the amounts of plutonium released from the establishment of La Hague. Long-shore gradients are apparent in the radionuclide distribution for Fucus. The discrepancy between the isotope ratios measured in the bio-indicator species and the releases from industrial sources leads to a discussion of the various source-terms affecting plutonium activities. Then concentration factors are defined. (author)

  1. 240Pu(n,f), 242Pu(n,f), 237Np(n,f), neutron fission cross sections, Esub(n) = 2.5 MeV

    Measurements of the absolute neutron fission cross section of 240Pu, 242Pu and 237Np have been made at 2.5 MeV using a hybrid detector. The fission events were detected in an ionization chamber (2π) and the neutron flux was determined by a proton recoil telescope and a directional long counter. Our values are compared to previous data

  2. Perturbation in the 240Pu/239Pu global fallout ratio in local sediment following the nuclear accidents at Thule (Greenland) and Palomares (Spain)

    It is well established that the main source of the plutonium found in marine sediments throughout the Northern Hemisphere is global stratospheric fallout, characterized by a typical 240Pu/239Pu atom ratio of ∼0.18. Measurements of perturbations in this ratio at various sites which had been subjected to close-in fallout, mainly from surface-based testing, has confirmed the feasibility of using this ratio to distinguish plutonium from different fallout sources. In the present study, the 240Pu/239Pu ratio has been examined in samples of sediment collected at Thule (Greenland) and Palomares (Spain), where accidents involving the release and dispersion of plutonium from fractured nuclear weapons occurred in 1968 and 1966, respectively. The 240Pu/239Pu ratio was measured by high-resolution alpha spectrometry and spectral deconvolution. The analytical results showed that at Thule the mean 240Pu/239Pu atom ratio was 0.033±0.004, while at Palomares the equivalent ratio appeared to be significantly higher at 0.056±0.003. Both ratios are consistent with those reported for soils samples at the Nevada site and Nagasaki, and are clearly indicative of weapons-grade plutonium. 27 refs., 1 fig., 2 tabs

  3. Deposition of [sup 210]Pb, [sup 137]Cs, [sup 239+240]Pu, [sup 238]Pu, and [sup 241]Am in the Antarctic peninsula area

    Roos, P.; Holm, E.; Persson, R.B.R. (Lund Univ. (Sweden). Dept. of Radiation Physics); Aarkrog, A.; Nielsen, S.P. (Risoe National Lab., Roskilde (Denmark))

    1994-01-01

    [sup 210]Pb, [sup 137]Cs, [sup 239+240]Pu, [sup 238]Pu, and [sup 241]Am were analysed in lichen, moss, grass and soil samples, as well as in lake sediments, from the South Shetland Islands, the Antarctic, in order to evaluate the flux and deposition of these elements. Average inventories of the analysed radionuclides in 1988 are given. The ratios [sup 238]Pu/[sup 239+240]Pu and [sup 241]Am/[sup 239+240]Pu of 0.21 [+-] 0.04 and 0.35 [+-] 0.08 respectively agree well with expected values in this area. A significant difference in [sup 137]Cs/[sup 239+240]Pu ratios between lichens and moss/grass/soil is observed which may be an effect of submerging and melt water altering radionuclide ratios. From one of three lakes studied it is possible to perform [sup 210]Pb dating with reasonable accuracy showing an average annual sediment accumulation in this lake of about 45 g m[sup -2]. (author).

  4. Identification of the contamination source of plutonium in environmental samples with isotopic ratios determined by inductively coupled plasma mass spectrometry and alpha-spectrometry

    Concentrations of 239+249Pu in environmental samples were determined by ICP-MS and α spectrometry, showing consistent results, which suggests an applicability of ICP-MS to 239Pu and 240Pu measurement. The activity ratios of 238Pu/239+240Pu and 240Pu/239Pu were significantly different in samples from the general environment and near Sellafield reprocessing plants, indicating the usefulness of these ratios for identification of the Pu contamination source. (author)

  5. 239+240Pu and 137Cs concentrations in fish, cephalopods, crustaceans, shellfish, and algae collected around the Japanese coast in the early 1990s

    Marine organisms, i.e. fish, cephalopods, crustaceans, shellfish, and algae, were collected in the early 1990s along the Sea of Japan coast and the Japanese Pacific coast and analyzed for their 239+240Pu and 137Cs concentrations. The 239+240Pu concentrations in muscle of fish were below 0.4 mBq/kg wet wt. and the lowest among the analyzed marine organisms. Most 137Cs concentrations in muscle of fish ranged from 100 to 300 mBq/kg wet wt. Higher concentrations of 239+240Pu, ranging from 1.6 to 5.7 mBq/kg wet wt., were observed in viscera of cephalopods than in their muscle. The 239+240Pu concentrations in whole soft tissues of bivalves varied approximately one order of magnitude from 0.8 to 6.1 mBq/kg wet wt., while 137Cs concentrations had little variation, being approximately 60 mBq/kg wet wt. The 239+240Pu concentrations in algae had a wide variation, ranging from 1.7 to 42.3 mBq/kg wet wt., and were higher than those of the other marine organisms. No statistically significant difference in mean concentrations of 239+240Pu was detected among the whole soft tissues of bivalves, viscera of cephalopods and crustaceans, and whole bodies of cephalopods and crustaceans within the 95% confidence limit. The mean concentrations of 137Cs became higher in the order, cephalopods and crustaceans and bivalves, algae, viscera of fish, muscles of fish. The mean concentrations of 239+240Pu were comparable for algae collected along the Japan Sea coast and the Pacific coast. Furthermore, the difference in mean concentrations of 137Cs in algae between the Japan Sea coast and the Pacific coast was not statistically significant within the 95% confidence limit. These results can be considered to indicate no definite influence from radioactive dumping into the Japan Sea by the former USSR and Russia with respect to radioactive pollution of marine organisms collected along the Japanese coast

  6. Using 239+240Pu atmospheric deposition and a simplified mass-balance model to re-estimate the soil erosion rate. A case study of Liaodong Bay in China

    By using the mass balance model of 137Cs and introducing 239+240Pu atmospheric deposition, a simplified mass balance model of 239+240Pu was developed and the soil erosion rate was re-estimated. The results indicated that the reference inventory of 239+240Pu was estimated to be 88.4 Bq/m2 in Liaodong Bay. In addition, the atomic ratios of 240Pu/239Pu in all core samples were approximately 0.18, which indicated that the major source of Pu was the global fallout. Statistical analysis of the erosion rates derived from the model demonstrates that the 239+240Pu atmospheric deposition is a feasible way to estimate the soil erosion rate and further improve tracer technique to assess the soil erosion rate. (author)

  7. Plutonium isotopes in marine sediments and some biota from the Sudanese coast of the Red Sea

    Measurements of 239+240Pu and 238Pu were carried out on marine biota as well as on sediments from the fringing reefs area extending towards north and south (Flamingo Bay) of Port Sudan harbour. The analyses were performed using radiochemical separation and alpha spectrometry. The range of the activity concentrations in marine sediments, in mBq kg-1 dry weight, was found to be from 5.10 to 82.00 for 239+240Pu and from 0.89 to 8.63 for 238Pu. Corresponding activity concentrations of 239+240Pu and 238Pu in sediments from the harbours at Port Sudan and Sawakin were 53-301 and 8.29-28.6 (Port Sudan) and 163-343 and 4.7 (Sawakin), respectively. The higher values for plutonium in marine algae suggest their suitability as an indicator species for monitoring purposes. The results obtained are generally lower than those found by other studies and show that the Red Sea environment is mildly affected by plutonium contamination. Activity ratios of plutonium isotopes confirm that the existence of plutonium in the Red Sea is mainly due to atmospheric global fallout. (authors)

  8. Alpha-activities in environmental samples

    Determination of 239Pu(240Pu) in human lungs from autopsies show for the period 1961 - 1965 lung burdens between 150 - 600 fCi and about 50 fCi/organ for the years 1978/79. In some cases also 241Am and 234U/238U contents were analyzed. Air concentration measurements concerning 239Pu(240Pu) and uranium isotopes were carried out using air filters taken between 1962 - 1979 at a sampling station in Vienna. Additionally performed investigations about the α-activity of typical food stuffs allow a rough estimation of the intake for the general population. Based on statistical data and the results of activity measurements especially of 210Po, 226Ra, 232Th and U(nat) in coals and the ashes, emissions from coal fired stationary sources are discussed. (Author)

  9. Determination of 90Sr, 137Cs and (239+240)Pu in waters with use of preliminary concentration

    A method for the simultaneous determination of artificial radionuclides (90Sr, 137Cs and (239+240)Pu) in water samples is described. The following preconcentration steps are used: co-precipitation of cesium on copper ferrocyanide; co-precipitation of plutonium on iron hydroxide; and precipitation of strontium in the carbonate form. The chemical yield is determined by using the tracers: 88Y, 85Sr, 134Cs and 236Pu or 242Pu. The method was applied to the determination of artificial radionuclides in water sources at nuclear test sites - the former Semipalatinsk nuclear test site and the 'Azgir' and 'Lira' test sites. The volume of water samples was 0.5 - 30.0 l, and the mineralization ranged from 0.1g/l to 100 g/l. The determination limits were: < 1 mBq/l for cesium-137; 0.02 mBq/l for plutonium-(239+240); and 1.5 mBq/l for strontium-90. The chemical yield was 60 - 90%

  10. Distribution of 90Sr, 137Cs and 239,240Pu in Caspian Sea water and biota

    Povinec, Pavel P.; Froehlich, Klaus; Gastaud, Janine; Oregioni, Beniamino; Pagava, Samson V.; Pham, Mai K.; Rusetski, Vladimir

    2003-09-01

    Two sampling expeditions were carried out in the Caspian Sea in 1995 and 1996. The aim was to investigate oceanographic conditions, water dynamics of the Sea and to measure radionuclide concentrations using 90Sr, 137Cs and 239,240Pu as tracers in the water column. Of the three basins comprising the Caspian Sea, the two deep basins (the central and southern basins) appear to be rapidly ventilated on a time scale of about 30 years, as shown by the penetration of radionuclides to bottom waters. The main source of radionuclides in the Sea has been global fallout and subsequent river run-off from catchment areas. At the stations visited, there were no signs of radioactive waste dumping, although the 90Sr levels found were higher than expected from global fallout, which may be due to remobilization of 90Sr from soil and its transport by rivers to the Sea. Radionuclide concentrations in fish and caviar are within the expected ranges and are not of radiological importance for consumption of fish and caviar from the Caspian Sea.

  11. Using uncertainty analyses to test for differences in fractional transfers of 238Pu and 239+240Pu to cattle grazing a contaminated arid environment

    This paper reports the results of Monte Carlo uncertainty and sensitivity analyses of the modeled fractional transfers of 238Pu and 239+240Pu from the gastrointestinal tract to the tissues of cattle that grazed a plutonium contaminated arid site near the Nevada Test Site. The analyses were conducted to assess the uncertainty in model parameters for the purpose of testing if the fractional transfer of 238Pu was greater than that of 239+240Pu to the tissues of the cattle. A sensitivity analysis of the fractional transfer model indicated that the Pu tissue concentration was the model parameter that had the highest correlation with computed fractional transfers. It was shown that accurate information on the variability of tissue concentrations is needed to obtain accurate estimates of the uncertainty of modeled fractional transfers. 34 refs., 3 figs., 5 tabs

  12. Comparison of the ENDF/B-V and SOKRATOR evaluations of 235U, 239Pu, 240Pu and 241Pu at low neutron energies

    The US and USSR's most recent evaluationsof 235U, 239Pu, 240Pu and 241Pu are compared over the thermal region and over the first few resonances. The two evaluations rest on essentially the same experimental data base and the differences reflect different approaches to the representation of the cross sections or different weightings of the experimental results. It is found that over the thermal and resolved ranges the two evaluations are very similar. Some differences in approaches are briefly discussed

  13. Estimates of /sup 239-240/Pu + 241Am inventory, spatial pattern, and soil tonnage for removal at nuclear site-201, NTS

    Estimates of /sup 239-240/Pu + 241Am inventory and spatial pattern in surface soil are given for Nuclear Site (NS)-201 in Area 18 on the Nevada Test Site (NTS). These estimates were obtained using Kriging techniques and the estimated average /sup 239-240/Pu to 241Am ratio of 7.5. (Henceforth, Pu and Am refer to /sup 239-240/Pu and 241Am.) Estimated concentration contours, 68% confidence bands on contours, and estimated average concentrations in 100- x 100-foot blocks are given. The total Pu + Am inventory estimated to be in the top 5 cm of soil over the defined area is approximately 9.4 curies. Lower and upper limits on this inventory estimate are 4 and 30 curies. It is estimated that about 33 acres (approx. = 13 hectares) of land are contaminated at levels greater than 160 pCi/g and about 51 acres (approx. = 21 hectares) to levels greater than 40 pCi/g. Approximately 23,000 tons of soil would need to be removed (to 15-cm depth) to clean up all areas with estimated concentrations greater than or equal to 160 pCi/g. About 36,000 tons would require removal at the 40- pCi/g level. The above estimates will be updated when additional data become available early in Calender Year 1980. 10 references, 7 figures, 1 table

  14. The concentration of 90Sr, 239,240Pu and 238Pu in the surface air of Prague in 1989 and 1990

    In 1989, positive values were found twice for 90Sr, namely in monitoring periods January-February (0.6 μBq.m-3) and September-October (0.8 μBq.m-3). In other monitoring periods, the concentrations of 90Sr in the surface air in Prague were below 0.3 μBq.m-3. Presence of 239,240Pu was not proved in Prague surface air in 1989. In the individual monitoring periods the concentrations of 239,240Pu were less than 0.13 μBq.m-3. In 1990, 90Sr concentrations in January-February and September-October were 2.1 and 1.2 μBq.m-3, respectively. In other monitoring periods, the concentrations of 90Sr were less than 0.3 μBq.m-3. The presence of 239,240Pu was not proved in Prague surface air in 1990 either. In the individual monitoring periods the concentrations were below 0.04 μBq.m-3. (Z.S.) 2 tabs., 8 refs

  15. Bioaccumulation of 239+240Pu in benthic organisms crab (Scylla serrata) and arca (Anadara granosa) : a case study from Trombay

    The study presents the concentration of (239+240)Pu in various size groups of crab (SCYLLA SERRATA) and arca (ANADARA GRANOSA). Around 96 crabs and 650 arcas were harvested from the Mumbai Harbour Bay. Crabs and arcas were grouped in different size groups as per their widths. The maximum concentration 239+240Pu is observed in case of crab for the lowest size group whereas for arca the same is observed in the highest size group. This difference in the uptake of (239+240)Pu is attributed to the difference in metabolic functions of the two species. Bio-accumulation factor (Bp) values in case of crab flesh ranged between 70 to 1140 kg-1 with a GM value of 180 and in arca the value ranged between 6 to 60 l kg-1 with a GM of 20. The values for shell were higher by factors of 2 to 9 in case of crab and 3 to 22 in case of arca. The smallest size group of crab shows maximum Bp value whereas for arca maximum Bp is observed for maximum size group. (author)

  16. Examining (239+240)Pu, (210)Pb and historical events to determine carbon, nitrogen and phosphorus burial in mangrove sediments of Moreton Bay, Australia.

    Sanders, Christian J; Santos, Isaac R; Maher, Damien T; Breithaupt, Joshua L; Smoak, Joseph M; Ketterer, Michael; Call, Mitchell; Sanders, Luciana; Eyre, Bradley D

    2016-01-01

    Two sediment cores were collected in a mangrove forest to construct geochronologies for the previous century using natural and anthropogenic radionuclide tracers. Both sediment cores were dated using (239+240)Pu global fallout signatures as well as (210)Pb, applying both the Constant Initial Concentration (CIC) and the Constant Rate of Supply (CRS) models. The (239+240)Pu and CIC model are interpreted as having comparable sediment accretion rates (SAR) below an apparent mixed region in the upper ∼5 to 10 cm. In contrast, the CRS dating method shows high sediment accretion rates in the uppermost intervals, which is substantially reduced over the lower intervals of the 100-year record. A local anthropogenic nutrient signal is reflected in the high total phosphorus (TP) concentration in younger sediments. The carbon/nitrogen molar ratios and δ(15)N values further support a local anthropogenic nutrient enrichment signal. The origin of these signals is likely the treated sewage discharge to Moreton Bay which began in the early 1970s. While the (239+240)Pu and CIC models can only produce rates averaged over the intervals of interest within the profile, the (210)Pb CRS model identifies elevated rates of sediment accretion, organic carbon (OC), nitrogen (N), and TP burial from 2000 to 2013. From 1920 to 2000, the three dating methods provide similar OC, N and TP burial rates, ∼150, 10 and 2 g m(-2) year(-1), respectively, which are comparable to global averages. PMID:26004816

  17. Measurement of plutonium isotopes in ground-level air in Northern-Germany - history and recent results

    The history of plutonium measurements performed on ground-level aerosols is summarised. Recent results are presented, and the activity ratios a(('2'39+240)Pu)/a(137Cs) and a(238Pu)/a(('2'39+240)Pu) measured are discussed and potential sources of 238Pu are considered. (author)

  18. Sources and Spatial Distribution of Metal Pollutants in Soils near the El Paso Smelter: A Forensic Study with Pb and Pu Isotopes.

    Ketterer, Michael; Moan, Matthew; Gremillion, Paul

    2010-05-01

    Lead and copper smelting has been conducted at El Paso since the late 1800's, and as a result, environmental media near the smelter have become contaminated. A study has been conducted to investigate the sources and spatial distribution of metal pollutants (Pb, Cd, Zn, Hg, As, Cu) and concomitant tracers (Ag, In, Sb, Bi) in soils from the smelter vicinity. Sampled locations were residential and non-residential locations in El Paso (Texas, USA), Anapra (New Mexico, USA) and Ciudad Juarez (Chihuahua, Mexico). Lead isotope studies indicate that the soil Pb is derived from smelting, and is consistent with two-component mixing between lead ores from Chihuahua (northern Mexico) having 206Pb/204Pb of 18.6 - 18.8 and ores from the Hanover, New Mexico (USA) mining district with 206Pb/204Pb of ~ 17.6. The Pb isotope results also exclude other common anthropogenic Pb sources such as paint and gasoline emissions as being major contributors. Concentrations of Hg and Pb of up to 10 and 11,000 ppm were found in surface soils within 1 km of the smelter. The metal concentration results clearly indicate that soils near the smelter ( 10 km distant). A general trend of decreasing concentrations vs. distance from the smelter was also observed. However, the results indicate that metal concentrations vary widely even at a fixed distance from the smelter point source. This phenomenon results from a combination of natural and anthropogenic processes that disturb and re-distribute soils in the surface environment. The site conditions consist of a very arid environment with little vegetation cover that is frequently disturbed by high winds and severe episodic rainfall. To study these effects, we have investigated stratospheric fallout plutonium (239+240Pu) as a proxy measure of disturbed vs. undisturbed soil conditions. The premise is that 'undisturbed' locations will have high 239+240Pu activities, and hence contain most or all of the cumulative deposition inventory of smelter pollutants

  19. First AID (Atom counting for Isotopic Determination).

    Roach, J. L. (Jeffrey L.); Israel, K. M. (Kimberly M.); Steiner, R. E. (Robert E.); Duffy, C. J. (Clarence J.); Roench, F. R. (Fred R.)

    2002-01-01

    Los Alamos National Laboratory (LANL) has established an in vitro bioassay monitoring program in compliance with the requirements in the Code of Federal Regulations, 10 CFR 835, Occupational Radiation Protection. One aspect of this program involves monitoring plutonium levels in at-risk workers. High-risk workers are monitored using the ultra-sensitive Therrnal Ionization Mass Spectrometry (TIMS) technique to ensure compliance with DOE standards. TIMS is used to measure atom ratios of 239Pua nd 240Puw ith respect to a tracer isotope ('Pu). These ratios are then used to calculate the amount of 239Pu and 240Pup resent. This low-level atom counting technique allows the calculation of the concentration levels of 239Pu and 240Pu in urine for at risk workers. From these concentration levels, dose assessments can be made and worker exposure levels can be monitored. Detection limits for TIMS analysis are on the order of millions of atoms, which translates to activity levels of 150 aCi 239Pua nd 500 aCi for 240Pu. pCi for Our poster presentation will discuss the ultra-sensitive, low-level analytical technique used to measure plutonium isotopes and the data verification methods used for validating isotopic measurements.

  20. Radiotoxicological analyses of 239+240Pu and 241Am in biological samples by anion-exchange and extraction chromatography: a preliminary study for internal contamination evaluations

    Many biological samples (urines and faeces) have been analysed by means of chromatographic extraction columns, utilising two different resins (AG 1-X2 resin chloride and T.R.U.), in order to detect the possible internal contamination of 239+240Pu and 241Am, for some workers of a reprocessing nuclear plant in the decommissioning phase. The results obtained show on one hand the great suitability of the first resin for the determination of plutonium, and on the other the great selectivity of the second one for the determination of americium

  1. Evaluation of fission cross sections and covariances for {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu

    Kawano, Toshihiko [Kyushu Univ., Fukuoka (Japan); Matsunobu, Hiroyuki [Data Engineering, Inc. (Japan); Murata, Toru [AITEL Corporation, Tokyo (JP)] [and others

    2000-02-01

    A simultaneous evaluation code SOK (Simultaneous evaluation on KALMAN) has been developed, which is a least-squares fitting program to absolute and relative measurements. The SOK code was employed to evaluate the fission cross sections of {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu for the evaluated nuclear data library JENDL-3.3. Procedures of the simultaneous evaluation and the experimental database of the fission cross sections are described. The fission cross sections obtained were compared with evaluated values given in JENDL-3.2 and ENDF/B-VI. (author)

  2. Measurement at n-TOF of the 237Np(n, γ) and 240Pu(n, γ) cross sections for the transmutation of nuclear waste

    The final design, safety assessment and precise performance analysis of transmutation devices such as Accelerator Driven Systems (ADS) or Fast Critical Reactors, need accurate and reliable nuclear data. The cross sections of 237Np and 240Pu have been measured in 2004 at n-TOF with good accuracy due to a combination of features unique in the world: high instantaneous neutron fluence and excellent energy resolution of the n-TOF facility [1], innovative Data Acquisition System based on flash ADCs and the use of a high performance BaF2 Total Absorption Calorimeter as a detection device. (authors)

  3. Preparation of isotopes and sources of actinide elements

    As the C.E.A. possesses no isotopic separation facility, the productions of isotopes of actinide elements are performed: a) by neutron irradiation and chemical treatment of special targets, b) by milking decay products from stocks of aged actinide elements, c) by chemical treatment of alpha active wastes. These productions concern the following isotopes: 233U, 238Pu, 242Pu, 243Cm, 242Cm, 244Cm (a); 228Th, 229Th, 234U, 237U, 239Np, 240Pu, 241Am, 248Cm (b); 237Np, 241Am (c). These isotopes are produced to satisfy French and international needs and are sent to users in various forms: solutions, metals, oxides, fluorides, or in different sources forms. The preparation of the sources represents an important field of activities divided into two parts: 1/Industrial sources: production of large series of different sources, 2/ Scientific sources: production of sources suitable for a specific scientific problem. A large overview of these activities is given

  4. Migration of plutonium isotopes in forest soil profiles in Lublin region (Eastern Poland)

    The distribution of Pu isotopes in three profiles of forest soil in Lublin region was determined. The retention half-time and migration velocity of 239,240Pu originated from global and Chernobyl fallouts was calculated. The average rate of migration of the global fallout plutonium was 0.4 cm/year and that of the Chernobyl one 0.7 cm/year. Good correlation between Pu concentration and organic matter contents was found only in the case of podzolic soil profile. In two profiles a good negative correlation between Pu activity and exchangeable pH of the soil layer was determined. (author)

  5. The neutron capture cross sections of 237Np(n,γ) and 240Pu(n,γ) and its relevance in the transmutation of nuclear waste

    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 237Np and 240Pu 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 237Np σ(n,γ) 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 240Pu σ(n,γ), the n-TOF σ(n,γ) 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

  6. 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

    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.

  7. {\\alpha}-accompanied cold ternary fission of $^{238-244}$Pu isotopes in equatorial and collinear configuration

    Santhosh, K P; Krishnan, Sreejith; Priyanka, B.

    2015-01-01

    The cold ternary fission of $^{238}$Pu, $^{240}$Pu, $^{242}$Pu and $^{244}$Pu isotopes, with $^{4}$He as light charged particle, in equatorial and collinear configuration has been studied within the Unified ternary fission model (UTFM). The fragment combination $^{100}$Zr+$^{4}$He+$^{134}$Te possessing the near doubly magic nuclei $^{134}$Te (N=82, Z=52) gives the highest yield in the alpha accompanied ternary fission of $^{238}$Pu. For the alpha accompanied ternary fission of $^{240}$Pu, $^{...

  8. Distribution of 137Cs, 90Sr, 239+240Pu, 241Am and 230,232Th on the fractions of natural organic species soils of ChNPP alienation zone

    The experimental data determination of distribution 137Cs, 90Sr, 239+240Pu, 241Am 'Chernobyl' releases and 230,232Th on the fraction of humic and fulvic acids sandy- podsolic, meadow and peaty soils taken in the exclusive zone ChNPP are presents. Soils organic matter was isolated by conventional alkali extraction (Turin's method). It was shown that, with depending of soils types 15-45 % 241Am associate with fulvic acids. In all investigated types of soils 30 - 40 % 239+240Pu connects with humic acids, as strong complexes. The distribution of environmental 230,232Th and artificial 239+240Pu on the fraction natural organic species is the same

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

    Strumińska-Parulska D. I.

    2013-04-01

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

  10. Distributions of long-lived anthropogenic radionuclides (14C, 129I and 239+240Pu) in coastal water columns off Sanriku, Japan

    The first commercial facility for reprocessing nuclear spent fuel in Japan is going to run in July 2006 and routine release of radionuclides to marine environment off Rokkasho will begin. Off Rokkasho area is located in the boundary where subarctic (Oyashio) and subtropical (Kuroshio) gyre mixes. And the Tsugaru Warm Current (TWC) flows into this region through the Tsugaru Strait and originates in the Kuroshio flowing in the Sea of Japan/the East Sea. Those three water masses of different origins and coastal water mass coexist in the surface layer of this domain. So it is important to clarify the distribution of anthropogenic radionuclides and their behaviors in the coastal seawater. Seawater samples were collected by use of CTD/Multi-Bottle Samplers (MBS) and large volume samplers (LVS) in October 2001 and June 2002. Carbon-14 and 129I were analyzed by accelerator mass spectrometry (AMS) and 239,240Pu was determined by the method of radiochemical separation and alpha spectrometry. Th long- lived radionuclide concentrations for all samples were in the range -233 - 75 per mille for Δ14C, not detected (N.D.) - 2.5x107 atoms/l for 129I, and N.D. - 0.025 mBq/l for 239,240Pu, respectively. The other anthropogenic radionuclides have the same concentration as those reported by the other organization. The vertical profiles of 14C and 129I decreased monotonically with depths. On the other hand, 239,240Pu profile have maximum at a depth of 500 - 700 m. The plots of potential density versus the concentrations designate that 14C and 129I virtually occurred in the water column lighter than the density of 26.6 - 26.8 and slightly penetrate into dense deeper layer. The maximum of Pu concentration existed at a density of 26.8 - 27.2. There is no difference of 129I concentration between two water masses (Oyashio and TWC) classified according to water temperature and salinity. Δ14C concentrations in TWC are higher than those in Oyashio, because TWC flows in sea surface over

  11. Studying of distribution of 137Cs, 90Sr, 239+240Pu, 241Am and 244Cm according to the organic acids fractions of the alienation zone soils

    The paper deals with data of research on the distribution of the radionuclides 137Cs, 90Sr, 239+240Pu, 241Am and 244Cm of ''the Chornobyl rains'' by the fractions of the organic matters of derno-podzolic sandy, derno-meadow and peat soils sampled in the alienation zone of the Chornobyl NPP. Functioning of organic matters was carried according to Tyurin's method. It is stressed that, independently on soil type, 137Cs is connected with the mineral contituent by 80-95%. It is found out that, independently on the soil type, 50-70% 137Sr and 15-45% 241Am are associated with fulvic acid fractions. The 241Am and 244Cm distribution according to organic acids taking into account deviations while carrying out determinations is unambiguous. It is found out that in all the soils tested the main quality of 239+24Pu is connected with humic acids

  12. Simultaneous measurement of 239Pu, 240Pu, 241Pu, and 242Pu by high resolution inductively coupled plasma mass spectrometer (HR ICP-MS) in marine sediments

    Transuranics elements are of particular interest in radioecological studies because of their radiotoxicity and their potential use to decipher source fingerprints and transport processes. The simultaneous measurement of 239Pu, 240Pu, 241Pu, and 242Pu in environmental samples requires a specific chemical procedure. This work deals with an analytical procedure which yields a very high grade of purification of Pu suitable for ultra low level detection by HR ICP-MS, from marine sediments. After the elimination of major elements (Fe, Al, Mg...) by a first chromatographic separation, a new device of purification by solvent extraction and concentration by a second chromatographic separation is used to obtain a concentrated and high purified solution of plutonium. The chemical procedure have been validated on IAEA certified sediment samples and on sediment samples collected in the roads of Cherbourg which had been previously analysed by other techniques (a spectrometry and thermo-ionisation mass spectrometer). (author)

  13. Dissolved forms of 90Sr, 239+240Pu and 241Am in the Sahan river waters from the Chernobyl area

    The dissolved forms of 90Sr, 239+240Pu and 241Am were studied for river water samples from the Chernobyl area in Ukraine on the basis of molecular size distribution. The river waters were collected at a station from Sahan River, which is a tributary of Pripyat River and located in the so-called Exclusion Zone (30-km zone), near the Chernobyl Nuclear Power Plant, in April and August 1996. The water samples had a pH of 7, conductivity of 190-210 mS m-1 and DOC concentration of 8-11 mg l-1. An ultrafiltration technique was used for the size-fractionation of the radionuclides in the river waters. Percentage of 90Sr, 239+240Pu and 241Am in the size fraction over 10,000 daltons was 2-20%, 68-79% and 57-62%, respectively. On the other hand, percentage of DOC and Si was 25-36% and 3%, respectively, for the size fraction over 10,000 daltons. These results indicate that 90Sr is present as cationic ions, but Pu and Am may be associated with organics of high molecular size and not with inorganic colloids such as aluminosilicate. In order to understand the association properties, laboratory experiments were performed for Am using humic substances isolated from the Sahan River water in April 1999 because of a significant fraction of dissolved organic materials and high complexation ability for actinides. The molecular size of 241Am in the presence of humic substances were studied for 0.01M NaClO4 solution at pH7 and the humic concentration of 10 mg l-1. The size patterns of 241Am were in good agreement with those of the river water samples. These results suggest that the dissolved forms of actinides in the Sahan River water are controlled by the presence of aquatic humic substances. (author)

  14. Geographic and vertical distribution of global fallout americium 241, plutonium isotopes and cesium 137 in lake sediments

    In this study, we present results concerning the activity concentrations of 241Am, 239-240Pu, 238Pu and 137Cs in lake sediments. Bulk cores for radionuclide inventories and high resolution cores for depth distribution are analysed

  15. Isotope dilution alpha spectrometry for the determination of plutonium concentration in irradiated fuel dissolver solution : IDAS and R-IDAS

    The report presents a new technique, Isotope Dilution Alpha Spectrometry (IDAS) and Reverse Isotope Dilution Alpha Spectrometry (R-IDAS) for determining the concentration of plutonium in the irradiated fuel dissolver solution. The method exploits sup(238)Pu in IDAS and sup(239)Pu in R-IDAS as a spike and provides an alternative method to Isotope Dilution Mass Spectrometry (IDMS) which requires enriched sup(242)Pu as a spike. Depending upon the burn-up of the fuel, sup(238)Pu or sup(239)Pu is used as a spike to change the sup(238)Pu/(sup(239)Pu+sup(240)Puactivity ratio in the sample by a factor of 10. This change is determined by α-spectrometry on electrodeposited sources using a solid state silicon surface barrier detector coupled to a multichannel analyser. The validity of a simple method based on the geometric progression (G.P.) decrease for the far tail of the spectrum to correct for the tail contribution of sup(238)Pu peak (5.50 MeV) to the low energy sup(239)Pu + sup(240)Pu peak (5.17 MeV) is established. Results for the plutonium concentration on different irradiated fuel dissolver solutions with burn-uo ranging from J,000 to 100,000 MWD/TU are presented and compared with those obtained by IDMS. The values obtained by IDAS or R-IDAS and IDMS agree within 0.5%. (auth.)

  16. {sup 137}Cs, {sup 90}Sr, {sup 241}Am and {sup 239+240}Pu radionuclides speciation in soils of the former Semipalatinsk test site

    Kabdyrakova, A.M.; Kunduzbaeva, A.Y.; Lukashenko, S.N.; Magasheva, R.Y. [Institute of radiation safety and ecology (Kazakhstan)

    2014-07-01

    The paper presents results of studies into {sup 137}Cs and {sup 90}Sr, {sup 241}Am and {sup 239+240}Pu techno-genic radionuclides speciation in soils of ecosystems at different topography of the Semipalatinsk Test Site (STS), exposed to different nuclear testing. The data were obtained for radionuclides speciation in soils of the following STS ecosystems: - grassland ecosystems within near-portal areas of tunnels - horizontal adits constructed for nuclear testing, affected by radioactive-contaminated water flows from the tunnels of Degelen Site; - steppe ecosystems, exposed to ground radioactive contamination resulted from above-ground and aerial nuclear testing of different yield, as well as simulation (hydrodynamic and hydro-nuclear) experiments at 'Experimental Field' testing site. - steppe ecosystems, exposed to ground radioactive contamination caused by testing of liquid and powdery radiological warfare weapon (RWW) at Site '4 a'; - 'Northern' and 'Western' areas of STS, where concentration level of artificial radionuclides in soil is comparable with the level of global fall-outs ('background' areas). To study the radionuclides speciation, method of sequential extraction was applied, and water-soluble, exchange, organic mobile and tightly bound forms were separated. Feature of the studied grassland ecosystems is that they are developed solely along the bed of water streams flowing from tunnels and are located at small area of 1-2 m{sup 2}. Radioactive contamination of soil is caused by radioactive contaminant sorption by sediments. Despite the significant space limitation of the ecosystems content of radionuclides speciation in soil greatly varies, particularly readily-soluble and mobile forms. The variation may be explained by high humidity which makes possible both sorption and desorption processes. If basic radionuclides contributing to radioactive contamination of grassland soils at Degelen Site are {sup

  17. 137Cs, 90Sr, 241Am and 239+240Pu radionuclides speciation in soils of the former Semipalatinsk test site

    The paper presents results of studies into 137Cs and 90Sr, 241Am and 239+240Pu techno-genic radionuclides speciation in soils of ecosystems at different topography of the Semipalatinsk Test Site (STS), exposed to different nuclear testing. The data were obtained for radionuclides speciation in soils of the following STS ecosystems: - grassland ecosystems within near-portal areas of tunnels - horizontal adits constructed for nuclear testing, affected by radioactive-contaminated water flows from the tunnels of Degelen Site; - steppe ecosystems, exposed to ground radioactive contamination resulted from above-ground and aerial nuclear testing of different yield, as well as simulation (hydrodynamic and hydro-nuclear) experiments at 'Experimental Field' testing site. - steppe ecosystems, exposed to ground radioactive contamination caused by testing of liquid and powdery radiological warfare weapon (RWW) at Site '4 a'; - 'Northern' and 'Western' areas of STS, where concentration level of artificial radionuclides in soil is comparable with the level of global fall-outs ('background' areas). To study the radionuclides speciation, method of sequential extraction was applied, and water-soluble, exchange, organic mobile and tightly bound forms were separated. Feature of the studied grassland ecosystems is that they are developed solely along the bed of water streams flowing from tunnels and are located at small area of 1-2 m2. Radioactive contamination of soil is caused by radioactive contaminant sorption by sediments. Despite the significant space limitation of the ecosystems content of radionuclides speciation in soil greatly varies, particularly readily-soluble and mobile forms. The variation may be explained by high humidity which makes possible both sorption and desorption processes. If basic radionuclides contributing to radioactive contamination of grassland soils at Degelen Site are 137Cs and 90Sr, then at Experimental Field site these are transuranic radionuclides

  18. Radionuclides 137Cs, 90Sr, 241Am and 239+240Pu in vegetation cover of the former Semipalatinsk test site

    The Semipalatinsk Test Site (STS) is one of the largest testing grounds for nuclear weapons. Diverse nuclear explosions were carried out on its territory: 340 underground tests (sites 'Degelen', 'Balapan' and 'Sary-Uzen'), 30 surface and 86 nuclear air explosions (site for radioactive warfare agent (RWA) and 'Experimental Field'). Since the STS was shutdown a large amount of information about current radiological situation in its territory has been collected. In recent years, one of the main problems is gradual transfer of its lands for national economy. Under these conditions, an essential element for prediction of radioactive contamination levels of food products is radionuclides redistribution parameters in soil-plant system used in calculation of doses to the population living within STS territory. Until recently, matter of radionuclides migration from soil to plants has been poorly studied. Individual researches, more or less devoted to this issue occurred in the past, but have virtually no information about accumulation of transuranic radionuclides in plants. More regular studies in this direction have been initiated recently. Between 2007 and 2013 features of artificial radionuclides accumulation in certain plant species under radioactive tunnel watercourses at 'Degelen' site were studied. We've obtained statistically reliable data characterizing accumulation of radionuclides, including 239+240Pu and 241Am, in steppe plants at 'Experimental field' site. The content of radionuclides in plants was researched at the RWA site. Comprehensive ecological survey in order to release the lands to the national economic turnover investigated parameters of radionuclides accumulation in steppe grasses at conditionally 'background' areas of STS and some parts of radioactive trace plume caused by the explosion in 1953. To date, all the findings have been generalized. We present an integrated picture about accumulation of artificial radionuclides 137Cs, 90Sr, 239+240Pu and

  19. Vertical distributions of plutonium isotopes in marine sediment cores off the Fukushima coast after the Fukushima Dai-ichi Nuclear Power Plant accident

    W. T. Bu

    2013-04-01

    Full Text Available The Fukushima Dai-ichi Nuclear Power Plant (FDNPP accident led to the release of large amounts of radionuclides into the atmosphere as well as direct discharges into the sea. In contrast to the intensive studies on the distribution of the released high volatility fission products, such as 131I, 134Cs and 137Cs, similar studies of the actinides, especially the Pu isotopes, are limited. To obtain the vertical distribution of Pu isotopes in marine sediments and to better assess the possible contamination of Pu from the FDNPP accident in the marine environment, we determined the activities of 239+240Pu and 241Pu as well as the atom ratios of 240Pu/239Pu and 241Pu/239Pu in sediment core samples collected in the western North Pacific off Fukushima from July 2011 to July 2012. We also measured surface sediment samples collected from seven Japanese estuaries before the FNDPP accident to establish the comprehensive background baseline data. The observed results of both the Pu activities and the Pu atom ratios for the sediments in the western North Pacific were comparable to the baseline data, suggesting that the FDNPP accident did not cause detectable Pu contamination to the studied regions prior to the sampling time. The Pu isotopes in the western North Pacific 30 km off the Fukushima coast originated from global fallout and Pacific Proving Ground close-in fallout.

  20. Updated estimates of /sup 239-240/Pu + 241Am inventory, spatial pattern, and soil tonnage for removal at nuclear site-201, NTS

    These new estimates are based on 712 241Am soil concentrations including 185 data values not previously available. Estimates were obtained using essentially the same kriging techniques and the estimated average /sup 239-240/Pu to 241Am ratio of 7.5 used to obtain previous results. The total Pu + Am inventory estimated to be in the top 5 cm of soil over the 109 hectare study is approximately 16.3 curies. Lower and upper limits on this inventory estimate are about 6.7 and 45.6 curies, respectively. It is estimated that about 58 acres (approx. = 23 hectares) of land in the study are contaminated at levels greater than 40 pCi/g which includes about 40 acres (approx. = 16 hectares) at levels greater than 160 pCi/g. Approximately 28,000 tons of soil would need to be removed (to 15-cm depth) to clean up all areas with estimated concentrates greater than or equal to 160 pCi/g. About 41,000 tons would require removal at the 40 pCi/g level. 5 references, 6 figures, 2 tables

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

    Full text: The determination of the association percentages of transuranics to different sediment phases could define their fate once they have been deposited onto the marine floor and their possible reactivity at the sediment/sea water interphase. Nowadays, there is a wide variety of leaching methods to extract transuranics from the different geochemical compounds conforming the sediments. Nevertheless, a general controversy is extended in the scientific world due to the extreme difficulty in testing their reliability, since the standards of transuranics linked to a certain sedimentary phase are not commercially available. Two mud subsamples taken from a storage container were analysed employing the same sequential extraction method, but with small handling differences.The following fractions were isolated: (1) Readily available (2) Carbonate bound and specifically adsorbed (3) Organically bound (4) Oxide and hydroxides bound and (5) residual. The 239,240Pu, 238Pu and 241Am extracted in each phase were analysed using standard radiochemical procedures. 241Pu was determined by both direct scintillation counting and through the 241Am in-growth up on the old disks containing Plutonium. The procedure for uncertainty calculations has been also included. (author)

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

    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)

  3. Estimation of covariances of 10B, 11B, 55Mn, 240Pu and 241Pu neutron nuclear data in JENDL-3.2

    Covariances of nuclear data have been estimated for 5 nuclides contained in JENDL-3.2. The nuclides considered are 10B, 11B, 55Mn, 240Pu, and 241Pu, which are regarded as important for the nuclear design study of fast reactors. The physical quantities for which covariances are deduced are cross sections, resolved and unresolved resonance parameters, and the first order Legendre-polynomial coefficient for the angular distribution of elastically scattered neutrons. The covariances were estimated by using the same methodology that had been used in the JENDL-3.2 evaluation in order to keep a consistency between mean values and their covariances. The least-squares fitting code GMA was used in estimating covariances for reactions of which JENDL-3.2 cross sections had been evaluated by taking account of measurements. Covariances of nuclear model calculations were deduced by the KALMAN system. The covariance data obtained were compiled in the ENDF-6 format, and will be put into the JENDL-3.2 Covariance File which is one of JENDL special purpose files. (author)

  4. Estimation of covariances of {sup 10}B, {sup 11}B, {sup 55}Mn, {sup 240}Pu and {sup 241}Pu neutron nuclear data in JENDL-3.2

    Shibata, Keiichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakajima, Yutaka; Murata, Toru

    1998-08-01

    Covariances of nuclear data have been estimated for 5 nuclides contained in JENDL-3.2. The nuclides considered are {sup 10}B, {sup 11}B, {sup 55}Mn, {sup 240}Pu, and {sup 241}Pu, which are regarded as important for the nuclear design study of fast reactors. The physical quantities for which covariances are deduced are cross sections, resolved and unresolved resonance parameters, and the first order Legendre-polynomial coefficient for the angular distribution of elastically scattered neutrons. The covariances were estimated by using the same methodology that had been used in the JENDL-3.2 evaluation in order to keep a consistency between mean values and their covariances. The least-squares fitting code GMA was used in estimating covariances for reactions of which JENDL-3.2 cross sections had been evaluated by taking account of measurements. Covariances of nuclear model calculations were deduced by the KALMAN system. The covariance data obtained were compiled in the ENDF-6 format, and will be put into the JENDL-3.2 Covariance File which is one of JENDL special purpose files. (author)

  5. CALORIMETER-BASED ADJUSTMENT OF MULTIPLICITY DETERMINED 240PU EFF KNOWN-A ANALYSIS FOR THE ASSAY OF PLUTONIUM

    Dubose, F.

    2012-02-21

    In nuclear material processing facilities, it is often necessary to balance the competing demands of accuracy and throughput. While passive neutron multiplicity counting is the preferred method for relatively fast assays of plutonium, the presence of low-Z impurities (fluorine, beryllium, etc.) rapidly erodes the assay precision of passive neutron counting techniques, frequently resulting in unacceptably large total measurement uncertainties. Conversely, while calorimeters are immune to these impurity effects, the long count times required for high accuracy can be a hindrance to efficiency. The higher uncertainties in passive neutron measurements of impure material are driven by the resulting large (>>2) {alpha}-values, defined as the ({alpha},n):spontaneous fission neutron emission ratio. To counter impurity impacts for high-{alpha} materials, a known-{alpha} approach may be adopted. In this method, {alpha} is determined for a single item using a combination of gamma-ray and calorimetric measurements. Because calorimetry is based on heat output, rather than a statistical distribution of emitted neutrons, an {alpha}-value determined in this way is far more accurate than one determined from passive neutron counts. This fixed {alpha} value can be used in conventional multiplicity analysis for any plutonium-bearing item having the same chemical composition and isotopic distribution as the original. With the results of single calorimeter/passive neutron/gamma-ray measurement, these subsequent items can then be assayed with high precision and accuracy in a relatively short time, despite the presence of impurities. A calorimeter-based known-{alpha} multiplicity analysis technique is especially useful when requiring rapid, high accuracy, high precision measurements of multiple plutonium bearing items having a common source. The technique has therefore found numerous applications at the Savannah River Site. In each case, a plutonium (or mixed U/Pu) bearing item is divided

  6. Behavior of plutonium isotopes in the marine environment of Enewetak atoll

    There continue to be reports in the literature that suggest a difference in the behavior of 239+240Pu and 238Pu in some aquatic environments. Plutonium isotopes have been measured in marine samples collected over 3 decades form Enewetak atoll, one of the sites in the Marshall Islands used by the United States between 1946 and 1958 to test nuclear devices. The plutonium isotopes originated from a variety of complex sources and could possibly coexist in this environment as different physical-chemical species. However results indicate little difference in the mobility and biological availability of 239+240Pu and 238Pu. (author)

  7. Determination of 238Pu and 239+240Pu in soils of different agricultural regions of Guatemala

    This study allowed to determine the concentration of radioactivity alpha, due to contamination for plutonium in cultivated soils of different regions of Guatemala. They were carried out samplings for convenience in cultivated soils of 15 departments of the republic, determined in each soils sample, the activity concentration for plutonium 238Plutonium and 239+240Plutonium expressed in mili-becquerel by kilogram (mBq/Kg), which has been caused from all over the world by the different provoked liberations or accidents of radioactive particles to the atmosphere

  8. Distribution of the Pu and Am isotopes in the BOMARC missile site soil

    Full text: The activity concentrations as well as the activity and atomic ratios of the Pu and Am isotopes in different sizes of the soil sampled around BOMARC Missile Site were obtained by radiochemical analysis. The association pattern between the actinides and soil particles was investigated using a spherical model of a particle size with a variable radius. From the activity and atomic ratios of Pu and Am, the origin of the Pu and Am isotopes was identified in the BOMARC Missile Site soil. Plutonium is one of the transuranic elements which is primarily present in the environment as a result of human activity, namely as the fallout from nuclear weapon testings during the late 1940s through to the early 1960s, and accidental releases due to military mishaps. One particular mishap occurred in 1960 at McGuire Air Force Base in New Jersey, when a Boeing Michigan Aeronautical Research Center (BOMARC) missile caught fire and the warhead was partially melted by the fire. Although the missile did not explode, subsequent fire fighting activities contributed to the dispersion of weapons grade plutonium into the local environment. Soil samples around BOMARC site were taken to a depth of 2 inches by the U.S. Air Force Institute for Environment. The soil samples were blended and homogenized in a soil tumbler, and subdivided into approximately 20-gram samples. Grain size fractions were determined with sieves. Determination of 239,240Pu, 238Pu, 241Pu, 241Am and 239U was performed using a radiochemical method. After adding 242Pu, 243Am and 232U tracers, a total of a 2 g ashed soil sample was dissolved with concentrated HNO3 and HF and evaporated to dryness. Dissolution in HNO3/HF was repeated and again evaporated to dryness. The residue was dissolved in 9 M HCl. After filtration, the solution was passed over an anion exchange column (chloride form) to which the Pu was sorbed. The columns were washed with 9 M HCl followed by 8 M HNO3. This effluent was evaporated to dryness and

  9. Distribution of Pu and Am isotopes in BOMARC missile site soil

    Full text: The activity concentrations as well as the activity and atomic ratios of the Pu and Am isotopes in different sizes of the soil sampled around BOMARC Missile Site were obtained by radiochemical analysis. The association pattern between the actinides and soil particles was investigated using a spherical model of a particle size with a variable radius. From the activity and atomic ratios of Pu and Am, the origin of the Pu and Am isotopes was identified in the BOMARC Missile Site soil. Plutonium is one of the transuranic elements which is primarily present in the environment as a result of human activity, namely as the fallout from nuclear weapon testings during the late 1940s through to the early 1960s, and accidental releases due to military mishaps. One particular mishap occurred in 1960 at McGuire Air Force Base in New Jersey, when a Boeing Michigan Aeronautical Research Center (BOMARC) missile caught fire and the warhead was partially melted by the fire. Although the missile did not explode, subsequent fire fighting activities contributed to the dispersion of weapons grade plutonium into the local environment. Soil samples around BOMARC site were taken to a depth of 2 inches by the U.S. Air Force Institute for Environment. The soil samples were blended and homogenized in a soil tumbler, and subdivided into approximately 20-gram samples. Grain size fractions were determined with sieves. Determination of 239,240Pu, 238Pu, 241Pu, 241Am and 238U was performed using a radiochemical method. After adding 242Pu, 243Am and 232U tracers, a total of a 2 g ashed soil sample was dissolved with concentrated HNO3 and HF and evaporated to dryness. Dissolution in HNO3/HF was repeated and again evaporated to dryness. The residue was dissolved in 9 M HCl. After filtration, the solution was passed over an anion exchange column (chloride form) to which the Pu was sorbed. The columns were washed with 9 M HCl followed by 8 M HNO3. This effluent was evaporated to dryness and

  10. Plutonium isotopes in the terrestrial environment at the Savannah River Site, USA: a long-term study.

    Armstrong, Christopher R; Nuessle, Patterson R; Brant, Heather A; Hall, Gregory; Halverson, Justin E; Cadieux, James R

    2015-02-01

    This work presents the findings of a long-term plutonium (Pu) study at Savannah River Site (SRS) conducted between 2003 and 2013. Terrestrial environmental samples were obtained at the Savannah River National Laboratory (SRNL) in the A-Area. Plutonium content and isotopic abundances were measured over this time period by α particle and thermal ionization mass spectrometry (3STIMS). We detail the complete process of the sample collection, radiochemical separation, and measurement procedure specifically targeted to trace plutonium in bulk environmental samples. Total plutonium activities were determined to be not significantly above atmospheric global fallout. However, the (238)Pu/(239+240)Pu activity ratios attributed to SRS are substantially different than fallout due to past (238)Pu production on the site. The (240)Pu/(239)Pu atom ratios are reasonably consistent from year to year and are lower than fallout indicating an admixture of weapons-grade material, while the (242)Pu/(239)Pu atom ratios are higher than fallout values, again due to actinide production activities. Overall, the plutonium signatures obtained in this study reflect a distinctive mixture of weapons-grade, heat source, and higher burn-up plutonium with fallout material. This study provides a unique opportunity for developing and demonstrating a blue print for long-term low-level monitoring of trace plutonium in the environment. PMID:25535652

  11. Determination of {sup 238}Pu, {sup 239+240}Pu, {sup 241}Pu and {sup 241}Am in radioactive waste from IPEN reactor

    Geraldo, Bianca; Taddei, Maria Helena T.; Cheberle, Sandra M.; Ferreira, Marcelo T., E-mail: bgeraldo@cnen.gov.b, E-mail: mhtaddei@cnen.gov.b, E-mail: scsantos@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; Marumo, Julio T., E-mail: jtmarumo@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Ion exchange resin is a common type of radioactive waste arising from treatment of coolant water of the main circuit of research and nuclear power reactors. This waste contains high concentrations of fission and activation products. The management of this waste includes its characterization in order to determine and quantify specific radionuclides including those known as difficult-to-measure radionuclides (RDM). The analysis of RDMs generally involves expensive and time-consuming complex radiochemical analysis for purification and separation of the radionuclides. The objective of this work is to show an easy methodology for quantifying plutonium and americium isotopes in spent ion exchange resin, used for purification of the cooling water of the IEA-R1 reactor located at the Nuclear and Energy Research Institute, IPEN-CNEN/SP. The resins were destroyed by acid digestion, followed by purification and separation of the Pu and Am isotopes with anionic and chromatographic resins. {sup 238}Pu, {sup 239}+{sup 24}'0Pu, and {sup 24}'1Am isotopes were analyzed in an alpha spectrometer equipped with surface barrier detectors. {sup 241}Pu isotope was analyzed by liquid scintillation counting. Chemical recovery yield ranged from 73 to 98% for Pu and 77 to 98% for Am, demonstrating that the methodology is suitable for identification and quantification of the isotopes studied in spent resins. (author)

  12. Distributions of Pu isotopes in seawater and bottom sediments in the coast of the Japanese archipelago before and soon after the Fukushima Dai-ichi Nuclear Power Station accident

    A radioactivity measurement survey was carried out from 24 April 2008 to 3 June 2011 to determine the levels of plutonium isotopes and 240Pu/239Pu atom ratios in the marine environments off the sites of commercial nuclear power stations around the Japanese islands; the sampling period extended to two months after the Fukushima Dai-ichi Nuclear Power Station accident. In our previous study (Oikawa et al., 2015), data on Pu isotopes and 241Am in sediments have already been reported. In this study, we report those on Pu isotopes in seawater as well as sediments, and the characteristics of sediments in addition (e.g., ignition loss and biogenic opals). Concentrations of 239+240Pu in seawater and bottom sediments remained nearly constant at all sampling locations during the survey period. In addition, no regional differences were observed in the 239+240Pu concentrations in surface waters. Higher 239+240Pu concentrations were found in bottom waters at deeper sampling locations, but the 240Pu/239Pu atom ratios were nearly constant regardless of the water depth. Higher 239+240Pu concentrations were also found in bottom sediments at deeper sampling locations, but vice versa for 240Pu/239Pu atom ratios as reported in the previous report. The sediments samples from deeper locations showed the higher percentage of ignition loss as well as the higher content of biogenic opal. There was likely to be some driving force participating in the transfer of Pu isotopes associated with biogenic substances to the deeper seabed. The present survey showed that the accident at the Fukushima Dai-ichi Nuclear Power Station did not contribute much to the inventory of Pu isotopes in the adjacent sea area. - Highlights: • Pu concentration off the Japan coast before and after FDNPS accident was measured. • No regional differences were observed in 239+240Pu concentrations in surface waters. • 240Pu/239Pu atom ratios were also nearly identical in seawaters. • There were no significant

  13. Isotopic Pu, Am and Cm signatures in environmental samples contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident

    Dust samples from the sides of roads (black substances) have been collected together with litter and soil samples at more than 100 sites contaminated heavily in the 20-km exclusion zones around Fukushima Dai-ichi Nuclear Power Plant (FDNPP) (Minamisoma City, and Namie, Futaba and Okuma Towns), in Iitate Village located from 25 to 45 km northwest of the plant and in southern areas from the plant. Isotopes of Pu, Am and Cm have been measured in the samples to evaluate their total releases into the environment from the FDNPP and to get the isotopic compositions among these nuclides. For black substances and litter samples, in addition to Pu isotopes, 241Am, 242Cm and 243,244Cm were determined for most of samples examined, while for soil samples, only Pu isotopes were determined. The results provided a coherent data set on 239,240Pu inventories and isotopic composition among these transuranic nuclides. When these activity ratios were compared with those for fuel core inventories in the FDNPP accident estimated by a group at JAEA, except 239,240Pu/137Cs activity ratios, fairly good agreements were found, indicating that transuranic nuclides, probably in the forms of fine particles, were released into the environment without their large fractionations. The obtained data may lead to more accurate information about the on-site situation (e.g., burn-up, conditions of fuel during the release phase, etc.), which would be difficult to get otherwise, and more detailed information on the dispersion and deposition processes of transuranic nuclides and the behavior of these nuclides in the environment

  14. Sequential determination of 239,240Pu, 238 Pu, 241 Am and 90Sr in radioactive wastes using SPE sorbents Analig Pu02, AnaLig Sr01 and TRU Resin

    A simple and rapid method of the sequential determination of radionuclides 239,240Pu, 238 Pu, 241 Am and 90Sr in radioactive sludge from the NPP Bohunice A1 with high radiochemical yields and efficient removal of interfering components from a matrix was developed. Separation method combines SPE sorbents Analig Pu02, AnaLig Sr01 made by IBC Advanced Technologies and TRU Resin (Eichrom Technologies) placed in tandem. Advantage of a single-stage column located on the vacuum box with a rapid flow is an effective pre-concentration and separation of radionuclides and minimization of sample separation time. (authors)

  15. Development and evaluation of an alpha spectrometer for precise measurement of activity ratio of plutonium

    In reprocessing plants, alpha spectrometry is used for the determination of plutonium concentration by isotope dilution alpha spectrometry. 238Pu content and for isotope correlations to calculate the specific activity and isotope composition of plutonium. All these studies involve the use of an alpha spectrometer to measure the activity ratio of 238Pu/(239Pu+240Pu) precisely. Technical Physics and Prototype Engineering Division (TPPED) of Bhabha Atomic Research Centre (BARC), Trombay, India has recently developed an alpha spectrometer, performance evaluation of which has been carried out by employing it to determine the activity ratio measurements of plutonium. Comparison of its performance with a commercially available system demonstrates that the indigenously developed instrument does provide acceptable levels of precision and accuracy for the activity ratio measurements of plutonium. (author)

  16. Analysis Method of 241Pu Radioactivity by Isotope Dilution-Extraction Liquid Scintillation Spectrometer

    2008-01-01

    <正>241Pu is the only pure β emitter with the maximum energy of 20.81 keV in plutonium isotopes of 238Pu, 239Pu, 240Pu and 242Pu, in which 241Pu is mostly specific radioactivity because its half-life is 14.29 a.

  17. Identifying Sources of Non-fallout Nuclear Contamination in Hudson River Sediments by Plutonium and Neptunium isotope ratios.

    Kenna, T. C.; Chillrud, S. N.

    2002-12-01

    In an effort to identify and characterize nuclear contaminants released from sources contained within the Hudson River drainage basin, Pu isotopes and 237Np have been measured in a series of sediment cores collected from various locations within the region. During the last several decades, the Hudson River has received input of radioactive contamination from several sources. The first and most significant, has been global fallout, which was a result of atmospheric testing of nuclear weapons primarily by governments of the United States and Former Soviet Union in the 1950s and 1960s. The second, is contamination resulting from reactor releases at the Indian Point Nuclear Power Plant (IPNPP) located on the Hudson River about 35 miles north of New York City. This facility began operation in 1962. A third source of radioactive contamination to the region is contamination resulting from activities at the Knolls Atomic Power Laboratory (KAPL) located on the Mohawk River, which began operation in 1946. Our research entails identifying different sources of nuclear contamination by measurement of plutonium and neptunium isotopic ratios by inductively coupled plasma mass spectrometry (ICP-MS). The isotopic composition of a nuclear contaminant is a sensitive indicator of its origin. By comparing the isotopic composition measured in fluvial sediments to mean values reported for global fallout (i.e. 240Pu/239Pu = 0.18 ñ 0.014, 237Np/239Pu = 0.48 ñ 0.07, and 241Pu/239Pu = .00194 ñ 00028) it is possible to identify contaminants as non-fallout in origin. To date, we have analyzed selected samples from 3 sediment cores collected from the following locations: 1) the Mohawk River downstream of KAPL, 2) the Hudson River above its confluence with the Mohawk River, and 3) the lower Hudson River at a location in close proximity to IPNPP. Isotopic analysis of sediments from the Mohawk River indicates contamination that is clearly non-fallout in origin (240Pu/239Pu ranges between 0

  18. Isotopic signature of plutonium at Bikini atoll

    Atom ratios of the isotopes 239Pu, 240Pu, 241Pu and 244Pu were determined in sediments and soils from Bikini atoll using low energy Accelerator Mass Spectrometry. All samples had been contaminated by local fallout from nuclear weapon testing between 1946 and 1958 and show significant variations in the isotopic composition, which are ascribed to the different yields of single tests and to the mixture of material from various devices. Differences in the 244Pu/239Pu ratio (2.8-5.7x10-4) are more pronounced than in the 240Pu/239Pu ratio of the same samples and provide complementary information to distinguish the sources of contamination.

  19. The indirect plutonium isotopes' content in the ChNPP restricted zone soil samples

    There is presented the procedure of indirect specific activity determination of radioisotopes238Pu and 239+240Pu in the samples of Ch NPP exclusion zone objects and environmental based on the measured specific activity values of reference radionuclides 90Sr and 154Eu, and determined reference radionuclides weighting factors. Reference radionuclides specific activities are determined by scintillation spectrometers of beta-, gamma-radiation energies. Weighting factors are determined by calibration measurements using radiochemical procedures of plutonium determination.The indirect measurements of specific activity radioisotopes 238Pu and 239+240Pu range is within 1 to 30000 Bq/kg

  20. Sector field inductively coupled plasma mass spectrometry in the elemental and isotopic analysis of lanthanides and actinides

    Plutonium is one element which is indispensable in identifying the source and for estimating the hazardous effects of rad. The isotopic ratios of plutonium (240Pu/239Pu) and its total concentration in environmental samples were also precisely estimated by high resolution inductively coupled plasma mass spectrometry

  1. Transport process of Pu isotope in marginal seas of the western North Pacific Ocean

    Significant quantities of Pu isotopes have been released into the marine environment as the result of atmospheric nuclear weapons testing. Most radionuclides globally dispersed in atmospheric nuclear weapons testing were released into the environment during the 1950's and 1960's. In the western North Pacific Ocean, the principal source can be further distinguished as two distinct sources of Pu: close-in tropospheric fallout from nuclear weapons testing at the Pacific Proving Grounds (PPG) in the Marshall Islands and global stratospheric fallout. Since the 240Pu/239Pu atom ratio is characteristic for the Pu emission source, information on Pu isotopic signature is very useful to better understand the transport process in the oceans and to identify the sources of Pu. The mean atom ratio of 240Pu/239Pu from the global stratospheric fallout is 0.180 ±0.014 based on soil sample data, whereas that from close-in tropospheric fallout from the PPG is 0.33 - 0.36. The 240Pu/239Pu atom ratios in seawater samples collected in marginal seas of the western North Pacific Ocean will provide important and useful data for understanding the process controlling Pu transport and for distinguishing future Pu sources. The objectives of this study were to measure the 239+240Pu concentrations and 240Pu/239Pu atom ratios in seawater from the Sea of Okhotsk, Japan Sea, South China Sea and Sulu Sea and to discuss the transport process of Pu. Large-volume seawater samples (250 L each) were collected from the surface to the bottom in marginal seas of the western North Pacific Ocean with acoustically triggered quadruple PVC sampling bottles during the R/V Hakuho-Maru cruise. The 239Pu and 240Pu concentrations and 240Pu/239Pu atom ratios were measured with a double-focusing SF-ICP-MS, which was equipped with a guard electrode to eliminate secondary discharge in the plasma and to enhance overall sensitivity. In the Sea of Okhotsk, the 239+240Pu concentration was 2.8 mBq m-3 in the surface water

  2. Removal of low level of 239+240Pu in aqueous solution between pH 2-6 by calcium alginate and its variation with aquatic humic substance

    During this work laboratory simulated experiments were carried out for the removal of low level of 239+240Pu from the aqueous solution. Water samples after filtering through 0.22 mm filter paper were spiked with 250 Bq/1 of 239+240Pu as Pu(NO3)4. The pH of the solutions were controlled between 2-6 by using 0.01M NaOH/HNO3. Spiked samples were kept in the argon atmosphere for a week. The spiked water is passed separately through 20 cm column having about 4 gm of calcium alginate beads. Calcium-alginate beads were prepared by immobilising 2% sodium alginate in 0.2 M calcium chloride solution. At different pH about 95-98% Pu was retained in the beads and significant variation was not observed at pH range studied. To understand the impact of dissolved organic substance on the absorption characteristics of Pu(IV) on calcium-alginate beads, about 0.01% (weight/volume) humic acid solution was mixed in the ratio of 1-4/100 (V/V) experimental solutions. It was observed that the presence of organic matter decreased the absorption by 40% which clearly indicate the complexation of Pu(IV) with humic acid, which was not further forming complex within the alginate beads. The various physicochemical characteristics were measured before and after passing the solution. About 40% of Pu is recovered from sodium alginate beads by using 0.1 M HNO3. (author)

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

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

  4. Rapid Determination of Plutonium Isotopes in Environmental Samples Using Sequential Injection Extraction Chromatography and Detection by Inductively Coupled Plasma Mass Spectrometry

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

    2009-01-01

    This article presents an automated method for the rapid determination of 239Pu and 240Pu in various environmental samples. The analytical method involves the in-line separation of Pu isotopes using extraction chromatography (TEVA) implemented in a sequential injection (SI) network followed by det...

  5. Chronology of Pu isotopes and {sup 236}U in an Arctic ice core

    Wendel, C.C., E-mail: cato.wendel@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Oughton, D.H., E-mail: deborah.oughton@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Lind, O.C., E-mail: ole-christian.lind@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Skipperud, L., E-mail: lindis.skipperud@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway); Fifield, L.K., E-mail: keith.fifield@anu.edu.au [Department of Nuclear Physics, Australian National University, Canberra ACT 0200 (Australia); Isaksson, E., E-mail: elisabeth.isaksson@npolar.no [Norwegian Polar Institute, Fram Centre, Hjalmar Johansens Gate 14, N9296 Tromsø (Norway); Tims, S.G., E-mail: steve.tims@anu.edu.au [Department of Nuclear Physics, Australian National University, Canberra ACT 0200 (Australia); Salbu, B., E-mail: brit.salbu@umb.no [Isotope Laboratory, Department of Plant and Environmental Sciences, Agricultural University of Norway, P.O. Box 5003, N-1432 Aas (Norway)

    2013-09-01

    In the present work, state of the art isotopic fingerprinting techniques are applied to an Arctic ice core in order to quantify deposition of U and Pu, and to identify possible tropospheric transport of debris from former Soviet Union test sites Semipalatinsk (Central Asia) and Novaya Zemlya (Arctic Ocean). An ice core chronology of {sup 236}U, {sup 239}Pu, and {sup 240}Pu concentrations, and atom ratios, measured by accelerator mass spectrometry in a 28.6 m deep ice core from the Austfonna glacier at Nordaustlandet, Svalbard is presented. The ice core chronology corresponds to the period 1949 to 1999. The main sources of Pu and {sup 236}U contamination in the Arctic were the atmospheric nuclear detonations in the period 1945 to 1980, as global fallout, and tropospheric fallout from the former Soviet Union test sites Novaya Zemlya and Semipalatinsk. Activity concentrations of {sup 239+240}Pu ranged from 0.008 to 0.254 mBq cm{sup −2} and {sup 236}U from 0.0039 to 0.053 μBq cm{sup −2}. Concentrations varied in concordance with {sup 137}Cs concentrations in the same ice core. In contrast to previous published results, the concentrations of Pu and {sup 236}U were found to be higher at depths corresponding to the pre-moratorium period (1949 to 1959) than to the post-moratorium period (1961 and 1962). The {sup 240}Pu/{sup 239}Pu ratio ranged from 0.15 to 0.19, and {sup 236}U/{sup 239}Pu ranged from 0.18 to 1.4. The Pu atom ratios ranged within the limits of global fallout in the most intensive period of nuclear atmospheric testing (1952 to 1962). To the best knowledge of the authors the present work is the first publication on biogeochemical cycles with respect to {sup 236}U concentrations and {sup 236}U/{sup 239}Pu atom ratios in the Arctic and in ice cores. - Highlights: • Concentrations and atom ratios of Pu and {sup 236}U determined in an Arctic ice core. • Concentrations of U and Pu found to be higher pre- than post-moratorium. • U and Pu concentrations

  6. Plutonium isotopes in the atmosphere of Central Europe: Isotopic composition and time evolution vs. circulation factors.

    Kierepko, Renata; Mietelski, Jerzy W; Ustrnul, Zbigniew; Anczkiewicz, Robert; Wershofen, Herbert; Holgye, Zoltan; Kapała, Jacek; Isajenko, Krzysztof

    2016-11-01

    This paper reports evidence of Pu isotopes in the lower part of the troposphere of Central Europe. The data were obtained based on atmospheric aerosol fraction samples collected from four places in three countries (participating in the informal European network known as the Ring of Five (Ro5)) forming a cell with a surface area of about 200,000km(2). We compared our original data sets from Krakow (Poland, 1990-2007) and Bialystok (Poland, 1991-2007) with the results from two other locations, Prague (Czech Republic; 1997-2004) and Braunschweig (Germany; 1990-2003) to find time evolution of the Pu isotopes. The levels of the activity concentration for (238)Pu and for ((239+240))Pu were estimated to be a few and some tens of nBqm(-3), respectively. However, we also noted some results were much higher (even about 70 times higher) than the average concentration of (238)Pu in the atmosphere. The achieved complex data sets were used to test a new approach to the problem of solving mixing isotopic traces from various sources (here up to three) in one sample. Results of our model, supported by mesoscale atmospheric circulation parameters, suggest that Pu from nuclear weapon accidents or tests and nuclear burnt-up fuel are present in the air. PMID:27450248

  7. Individual economical value of plutonium isotopes and analysis of the reprocessing of irradiated fuel

    An economical analysis of plutonium recycle in a PWR reactor, without any modification, is done, supposing an open market for the plutonium. The individual value of the plutonium isotopes is determined solving a system with four equations, which the unknow factors are the Pu-239, Pu-240, pu-241 and Pu-242 values. The equations are obtained equalizing the cost of plutonium fuel cycle of four different isotope mixture to the cost of the uranium fuel cycle. (E.G.)

  8. The history and source of particulate 137Cs and 239,240Pu deposition in sediments of the Ob River Delta, Siberia

    This paper presents the first results of a project designed to examine the transfer of particle-associated artificial radionuclides down the Ob River in Siberia to its delta over the past 5 decades. The main sources include fallout from atmospheric nuclear weapons tests and weapons complexes and test sites of the Former Soviet Union in or near the Ob watershed. The approach is to measure the accumulation of the radionuclides in undisturbed delta sediments - obtaining a record of their deposition over time. These records were found in sediments of shallow lakes apart from, and connected to, the main channel. Sediment cores were collected in the summer of 1994 using a shallow draft catamaran to reach these lakes from a support ship in the main channel. Measurements are presented on the depth distributions of 137Cs and Pu isotopes and their inventories in a series of dated sediment cores - including one from a location in the Taz Estuary (which does not receive Ob River sediments). Sediment dating was carried out using the excess 210Pb technique. The results obtained are compared with known information on the temporal history of releases from the various sources and characteristics of the isotopic composition of the sources. The results show that good records of radionuclide deposition indicate that the major fraction of 137Cs and Pu isotopes deposited in these delta sediments comes from atmospheric nuclear weapons test fallout - both delivered directly from the atmosphere and from downstream transport of watershed sediments. No more than 25% of the observed inventories could be derived from other sources

  9. Distribution of Pu isotopes and 137Cs in and around the former soviet union's Semipalatinsk nuclear test site

    This paper is a report on our survey of residual radioactivity, Pu isotopes and 137Cs, within and without the territory of the Semipalatinsk nuclear test site. Soil samples within the test site were collected at approximately 30 sites along the roads connecting Kurchatov City, ground zero for the first USSR nuclear test, Balapan, Degelen Mountain and Salzhal settlement. Furthermore, outside the test site, the soil was sampled at about 20 sites, including some settlements (Mostik, Dolon, Tchagan, etc.), forest and pasture areas, along the roads from Semipalatinsk City to Kurchatov City and north Korosteli settlement. The contamination levels of long-lived radionuclides, 137Cs, 238Pu and 239,240Pu as well as 240Pu/239Pu atomic ratio in the soil were determined by non-destructive γ-spectrometric method and radiochemical separation followed by α-spectrometric and/or ICP-MS methods, respectively. The results showed that although 137Cs was within typical environmental levels except for an areas near ground zero and Balapan, 239,240Pu was elevated levels contaminated with weapons-grade plutonium in all area we visited. From the stepwise leaching of Pu from the soil, 50-80% of total 239,240Pu in most samples was found to be tightly incorporated into the soil components which might have been melted at time of detonation. (author)

  10. Determining the age and history of plutonium using isotope correlations and experimentally determined data on isotopic abundances of plutonium and 241Am

    Linear correlations using a data set of nominally cooled samples of Pu formed in Indian PHWRs using experimentally determined 241Pu/239Pu versus 240Pu/239Pu and 241Am/239Pu versus 240Pu/239Pu isotope ratios have been developed which can be used for determining the age of Pu. By correlating both Pu and Am isotopic information, an understanding of how the material was processed, when chemical separations occurred to remove 241Am as well as the true age of the Pu in sample can be obtained. Two actual samples from a PHWR with unknown origin were analyzed as a part of case study for application of this new methodology. (author)

  11. 90Sr, 238U, 234U, 137Cs, 40K and 239/240Pu in Emmental type cheese produced in different regions of Western Europe

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

  12. Distribution of Pu isotopes and {sup 137}Cs in and around the former soviet union`s Semipalatinsk nuclear test site

    Yamamoto, Masayoshi [Kanazawa Univ., Tatsunokuchi, Ishikawa (Japan). Low Level Radioactivity Laboratory; Hoshi, Masaharu; Takada, Jun; Tsukatani, Tsuneo; Sekerbaev, A.Kh.; Busev, B.I.

    1999-03-01

    This paper is a report on our survey of residual radioactivity, Pu isotopes and {sup 137}Cs, within and without the territory of the Semipalatinsk nuclear test site. Soil samples within the test site were collected at approximately 30 sites along the roads connecting Kurchatov City, ground zero for the first USSR nuclear test, Balapan, Degelen Mountain and Salzhal settlement. Furthermore, outside the test site, the soil was sampled at about 20 sites, including some settlements (Mostik, Dolon, Tchagan, etc.), forest and pasture areas, along the roads from Semipalatinsk City to Kurchatov City and north Korosteli settlement. The contamination levels of long-lived radionuclides, {sup 137}Cs, {sup 238}Pu and {sup 239,240}Pu as well as {sup 240}Pu/{sup 239}Pu atomic ratio in the soil were determined by non-destructive {gamma}-spectrometric method and radiochemical separation followed by {alpha}-spectrometric and/or ICP-MS methods, respectively. The results showed that although {sup 137}Cs was within typical environmental levels except for an areas near ground zero and Balapan, {sup 239,240}Pu was elevated levels contaminated with weapons-grade plutonium in all area we visited. From the stepwise leaching of Pu from the soil, 50-80% of total {sup 239,240}Pu in most samples was found to be tightly incorporated into the soil components which might have been melted at time of detonation. (author)

  13. Tracing the dispersion of contaminated sediment with plutonium isotope measurements in coastal catchments of Fukushima Prefecture

    Evrard, Olivier; Pointurier, Fabien; Onda, Yuichi; Chartin, Caroline; Hubert, Amélie; Lepage, Hugo; Pottin, Anne-Claire; Lefèvre, Irène; Bonté, Philippe; Laceby, J. Patrick; Ayrault, Sophie

    2015-04-01

    The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident led to important releases of radionuclides into the environment, and trace levels of plutonium (Pu) were detected in northeastern Japan. However, measurement of Pu isotopic atom and activity ratios is required to differentiate between the contributions of global nuclear test fallout and FDNPP emissions. In this study, we measured Pu isotopic ratios in recently deposited sediments along rivers draining the most contaminated part of the inland radioactive plume. To this end, we carried out a thorough chemical purification and concentration of Pu from sediment samples (5 g dry material) and precise isotopic measurements using a double-focusing sector field ICP-MS. Results showed that the entire range of measured Pu isotopes (i.e., 239Pu, 240Pu, 241Pu, and 242Pu) were detected in all samples, although in extremely low concentrations. The 241Pu/239Pu atom ratios measured in sediment deposits (0.0017-0.0884) were significantly higher than the corresponding values attributed to the global fallout (0.00113±0.00008 on average in the Northern Hemisphere between 31°-71°N). The results indicated the presence of Pu from FDNPP, in slight excess compared to the Pu background from global fallout, representing up to ca. 60% of Pu in the analyzed samples. These results demonstrate that this radionuclide has been transported relatively long distances (45 km) from FDNPP and deposited in rivers representing a potential source of Pu to the ocean.

  14. Comparative concentrations of 137Cs, 90Sr, /sup 239,240/Pu, and 241Am in tissues of fish from the Marshall Islands and calculated dose commitments from their consumption

    Body burdens of 90Sr, 137Cs, and the transuranics in bottom-feeding fish from Marshall Island atolls are derived, in part, from the quantities of the radionuclides irreversibly fixed to ingested carbonate material. Radionuclide concentration factors for different species of fish are characterized by relating tissue concentrations to those in filtered seawater. For bottom-feeding fish, the values are lower at the lesser contaminated atolls than those values determined for the same species at the more contaminated atolls. These fish have the ability to lower their gut pH during feeding. When this occurs, there is a dissolution of a fraction of the ingested calcium carbonate containing radionuclides that were fixed or fused internally to the material during nuclear testing. Fractions of the radionuclides released during solution in carbonate matrix are available for passage across the gut wall. Amounts released to solution in the gut are proportional to the levels of contamination at the different atolls. Concentration factors for higher trophic level species, which do not rely on sediments or coral for their source of food, show no such trends between differentially contaminated atolls. A two-source model used to compute the internal concentrations is described. Americium-241 seems to be more biologically available than /sup 239,240/Pu to higher trophic level species from the lagoons, whereas at lower trophic levels the opposite seems to be the case. Cesium-137 is now the largest contributor of the small radiological dose to man from the marine fish pathway, with the transuranics contributing from 2 to 30% of the total dose. 22 references, 1 figure, 19 tables

  15. Geochemical behaviour of plutonium isotopes in natural media (lakes, rivers, estuaries)

    Artificial radionuclide activities (238Pu, 239+240Pu) were measured in natural environments. Their distribution and geochemical behaviour are evaluated and compared them to these of the 137Cs. In a volcanic crater lake, influenced only by atmospheric fallout (Lac Pavin, France), sediments are enriched in 239+240Pu, whereas 137Cs stays in the dissolved phase. Diffusion processes and migration of radionuclides is shown to occur in sediments. Remobilization of 239+240Pu is probable at the sediment/water interface. In the Garonne-Dordogne, Seine and Loire rivers, the 239+240Pu activity levels in suspended matter are little influenced by the waste discharges of nuclear power plants. The element is essentially transported in the particulate fraction, more than is 137Cs. In all the esturies studied (Gironde, Seine, Loire) 239+240Pu concentrations in suspended matter increase between the river and the estuary. Simultaneously a removal of plutonium from the dissolved phase is observed. High plutonium concentrations are measured in the Seine estuary; they are attributed to a ''marine'' contamination: the French nuclear reprocessing plant of La Hague discharges low level radioactive liquid wastes, a part may reach the Seine estuary. There are no decrease in particulate 137Cs concentrations between the river and the estuary of the Gironde, such as it occurs in the Loire. In this last case, the phenomenon is explained by the presence of ''young caesium'' originating in the power plant effluents and which is more exchangeable than 137Cs of atmospheric origin. In the Seine estuary, the influence of marine contamination causes an increase of particulate and dissolved 137Cs concentrations

  16. Intercalibration of selected anthropogenic radionuclides for the GEOTRACES Program

    Kenna, Timothy C.; Masqué, Pere; Mas, Jose Luis;

    2012-01-01

    As part of the GEOTRACES Program, six laboratories participated in an intercalibration exercise on several anthropogenic radionuclides of interest. The effort was successful for 239,240Pu activity, 240Pu/239Pu isotope ratio, and 137Cs activity measured in filtered seawater samples from the Bermuda...

  17. Depositional behaviors of plutonium and thorium isotopes at Tsukuba and Mt. Haruna in Japan indicate the sources of atmospheric dust.

    Hirose, K; Igarashi, Y; Aoyama, M; Inomata, Y

    2010-02-01

    Monthly plutonium and thorium depositions at Tsukuba (28m asl) and Mt. Haruna (1370m asl) were measured during 2006 and 2007 (Jan 2006-Dec 2007 at Tsukuba, Nov 2006-Dec 2007 at Mt. Haruna). The monthly (239,240)Pu depositions ranged from 0.044 to 2.67mBq m(-2) at Tsukuba and from 0.05 to 0.9mBq m(-2) at Mt. Haruna during the measurement periods. Monthly (239,240)Pu deposition did not differ markedly between the two sites except in April 2007. Seasonal pattern of monthly (239,240)Pu depositions at both sites showed high in spring and low in summer, and typical of seasonal variations in northeastern Asia. Thorium deposition at Tsukuba was higher than that at Mt. Haruna except in May and June 2007. (230)Th/(232)Th activity ratios were used to partition deposition samples into locally and remotely derived fractions. The results revealed that a major proportion of total (239,240)Pu and Th deposits are derived from remote sources, especially in spring. PMID:19804923

  18. Isotopic neutron sources for neutron activation analysis

    This User's Manual is an attempt to provide for teaching and training purposes, a series of well thought out demonstrative experiments in neutron activation analysis based on the utilization of an isotopic neutron source. In some cases, these ideas can be applied to solve practical analytical problems. 19 refs, figs and tabs

  19. Plutonium in Soils from Northeast China and Its Potential Application for Evaluation of Soil Erosion

    Xu, Yihong; Qiao, Jixin; Hou, Xiaolin;

    2013-01-01

    Surface and soil core samples from northeast China were analyzed for Pu isotopes. The measured 240Pu/239Pu atomic ratios and 239 1 240Pu/137Cs activity ratios revealed that the global fallout is the dominant source of Pu and 137Cs at these sites. Migration behavior of Pu varying with land type an...

  20. First measurements of 236U concentrations and 236U/239Pu isotopic ratios in a Southern Hemisphere soil far from nuclear test or reactor sites

    The variation of the 236U and 239Pu concentrations as a function of depth has been studied in a soil profile at a site in the Southern Hemisphere well removed from nuclear weapon test sites. Total inventories of 236U and 239Pu as well as the 236U/239Pu isotopic ratio were derived. For this investigation a soil core from an undisturbed forest area in the Herbert River catchment (17°30′ – 19°S) which is located in north-eastern Queensland (Australia) was chosen. The chemical separation of U and Pu was carried out with a double column which has the advantage of the extraction of both elements from a relatively large soil sample (∼20 g) within a day. The samples were measured by Accelerator Mass Spectrometry using the 14UD pelletron accelerator at the Australian National University. The highest atom concentrations of both 236U and 239Pu were found at a depth of 2–3 cm. The 236U/239Pu isotopic ratio in fallout at this site, as deduced from the ratio of the 236U and 239Pu inventories, is 0.085 ± 0.003 which is clearly lower than the Northern Hemisphere value of ∼0.2. The 236U inventory of (8.4 ± 0.3) × 1011 at/m2 was more than an order of magnitude lower than values reported for the Northern Hemisphere. The 239Pu activity concentrations are in excellent agreement with a previous study and the 239+240Pu inventory was (13.85 ± 0.29) Bq/m2. The weighted mean 240Pu/239Pu isotopic ratio of 0.142 ± 0.005 is slightly lower than the value for global fallout, but our results are consistent with the average ratio of 0.173 ± 0.027 for the southern equatorial region (0–30°S). - Highlights: • Exploration of uranium-236 (236U) and plutonium-239 (239Pu) in the Southern Hemisphere by accelerator mass spectrometry. • We report the depth profile for both isotopes from a forest site well removed from nuclear test or reactor sites. • 236U and 239Pu were deposited at the same time due to nuclear weapons tests but show a slightly different depth dependence. • The

  1. Plutonium isotopic composition by gamma-ray spectroscopy

    We discuss the general approach, computerized data analysis methods, and results of measurements to determine the isotopic composition of plutonium by gamma-ray spectroscopy. The simple techniques are designed to be applicable to samples of arbitrary size, geometry, chemical and isotopic composition that have attained 241Pu-237U equilibrium. The combination of the gamma spectroscopic measurement of isotopic composition coupled with calorimetric measurement of total sample power is shown to give a totally nondestructive determination of sample Pu mass with a precision of 0.6% for 1000-g samples of PuO2 with 12% 240Pu content. The precision of isotopic measurements depends upon many factors including sample size, sample geometry, and isotopic content. Typical ranges are found to be 238Pu, 239Pu, 0.1 to 0.5%; 240Pu, 2 to 5%; 241Pu, 0.3 to 0.7%; 242Pu (determined by isotopic correlation); and 241Am, 0.2 to 10%

  2. Photonuclear activation of pure isotopic mediums.

    Grohman, Mark A.; Lukosi, Eric Daniel

    2010-06-01

    This work simulated the response of idealized isotopic U-235, U-238, Th-232, and Pu-239 mediums to photonuclear activation with various photon energies. These simulations were conducted using MCNPX version 2.6.0. It was found that photon energies between 14-16 MeV produce the highest response with respect to neutron production rates from all photonuclear reactions. In all cases, Pu-239 responds the highest, followed by U-238. Th-232 produces more overall neutrons at lower photon energies then U-235 when material thickness is above 3.943 centimeters. The time it takes each isotopic material to reach stable neutron production rates in time is directly proportional to the material thickness and stopping power of the medium, where thicker mediums take longer to reach stable neutron production rates and thinner media display a neutron production plateau effect, due to the lack of significant attenuation of the activating photons in the isotopic mediums. At this time, no neutron sensor system has time resolutions capable of verifying these simulations, but various indirect methods are possible and should be explored for verification of these results.

  3. Investigation of the oxidation states of Pu isotopes in a hydrochloric acid solution.

    Lee, M H; Kim, J Y; Kim, W H; Jung, E C; Jee, K Y

    2008-12-01

    The characteristics of the oxidation states of Pu in a hydrochloric acid solution were investigated and the results were applied to a separating of Pu isotopes from IAEA reference soils. The oxidation states of Pu(III) and Pu(IV) were prepared by adding hydroxylamine hydrochloride and sodium nitrite to a Pu stock solution, respectively. Also, the oxidation state of Pu(VI) was adjusted with concentrated HNO(3) and HClO(4). The stability of the various oxidation states of plutonium in a HCl solution with elapsed time after preparation were found to be in the following order: Pu(III) approximately Pu(VI)>Pu(IV)>Pu(V). The chemical recoveries of Pu(IV) in a 9M HCl solution with an anion exchange resin were similar to those of Pu(VI). This method for the determination of Pu isotopes with an anion exchange resin in a 9M HCl medium was applied to IAEA reference soils where the activity concentrations of (239,240)Pu and (238)Pu in IAEA-375 and IAEA-326 were consistent with the reference values reported by the IAEA. PMID:18674920

  4. The Activity Check of Brachytherapy Isotope

    An isotope Ir-192, which is used in brachytherapy depends on import in whole quantities. There are a few ways for its activity. measurement using Welltype chamber or the way to rely on authentic decay table of manufacturer. In-air dosimetry using Farmer Chamber, etc. In this paper, let me introduce the way using Farmer chamber which is easier and simple. With the Farmer chamber and source calibration jig, take a measurement the activity of an isotope Ir-192 and compare the value with the value from decay table of manufacturer and check the activity of source. The result of measurement, compared the value from decay table, by ±2.1. (which belongs to recommendable value for AAPM ±5% as difference of error range). It is possible to use on clinical medicine. With the increase in use of brachytherapy, the increase of import is essential. And an accurate activity check of source is compulsory. For the activity check of source, it was possible to use Farmer chamber and source calibration jig without additional purchase of Well type chamber.

  5. Isotopic composition and origin of uranium and plutonium in selected soil samples collected in Kosovo

    Danesi, P.R. E-mail: P.R.Danesi@iaea.org; Bleise, A.; Burkart, W.; Cabianca, T.; Campbell, M.J.; Makarewicz, M.; Moreno, J.; Tuniz, C.; Hotchkis, M

    2003-07-01

    Soil samples collected from locations in Kosovo where depleted uranium (DU) ammunition was expended during the 1999 Balkan conflict were analysed for uranium and plutonium isotopes content ({sup 234}U, {sup 235}U, {sup 236}U, {sup 238}U, {sup 238}Pu, {sup 239+240}Pu). The analyses were conducted using gamma spectrometry ({sup 235}U, {sup 238}U), alpha spectrometry ({sup 238}Pu, {sup 239+240}Pu), inductively coupled plasma-mass spectrometry (ICP-MS) ({sup 234}U, {sup 235}U, {sup 236}U, {sup 238}U) and accelerator mass spectrometry (AMS) ({sup 236}U). The results indicated that whenever the U concentration exceeded the normal environmental values ({approx}2 to 3 mg/kg) the increase was due to DU contamination. {sup 236}U was also present in the released DU at a constant ratio of {sup 236}U (mg/kg)/{sup 238}U (mg/kg)=2.6x10{sup -5}, indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg and, on the basis of the measured {sup 238}Pu/{sup 239+240}Pu, could be entirely attributed to the fallout of the nuclear weapon tests of the 1960s (no appreciable contribution from DU)

  6. Isotopic composition and origin of uranium and plutonium in selected soil samples collected in Kosovo

    Soil samples collected from locations in Kosovo where depleted uranium (DU) ammunition was expended during the 1999 Balkan conflict were analysed for uranium and plutonium isotopes content (234U, 235U, 236U, 238U, 238Pu, 239+240Pu). The analyses were conducted using gamma spectrometry (235U, 238U), alpha spectrometry (238Pu, 239+240Pu), inductively coupled plasma-mass spectrometry (ICP-MS) (234U, 235U, 236U, 238U) and accelerator mass spectrometry (AMS) (236U). The results indicated that whenever the U concentration exceeded the normal environmental values (∼2 to 3 mg/kg) the increase was due to DU contamination. 236U was also present in the released DU at a constant ratio of 236U (mg/kg)/238U (mg/kg)=2.6x10-5, indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg and, on the basis of the measured 238Pu/239+240Pu, could be entirely attributed to the fallout of the nuclear weapon tests of the 1960s (no appreciable contribution from DU)

  7. Further development of IDGS: Isotope dilution gamma-ray spectrometry

    The isotope dilution gamma-ray spectrometry (IDGS) technique for determining the plutonium concentration and isotopic composition of highly radioactive spent-fuel dissolver solutions has been further developed. Both the sample preparation and the analysis have been improved. The plutonium isotopic analysis is based on high-resolution, low-energy gamma-ray spectrometry. The plutonium concentration in the dissolver solutions then is calculated from the measured isotopic differences among the spike, the dissolver solution, and the spiked dissolver solution. Plutonium concentrations and isotopic compositions of dissolver solutions analyzed from this study agree well with those obtained by traditional isotope dilution mass spectrometry (IDMS) and are consistent with the first IDGS experimental result. With the current detector efficiency, sample size, and a 100-min count time, the estimated precision is ∼0.5% for 239Pu and 240Pu isotopic analyses and ∼1% for the plutonium concentration analysis. 5 refs., 2 figs., 7 tabs

  8. Plutonium source isotopic analysis with up to 25 mm Pb shielding using the FRAM Isotopic Analysis Code.

    Hypes, Philip A.

    2000-01-01

    The FRAM Isotopics Analysis Code has been used to analyze plutonium spectra taken through very thick shielding. Three plutonium sources with 240Pu content of 6.6%, 9.7%, and 16.3% were measured with lead shielding thicknesses ranging from zero to 25.3 mm, in nominal increments of 1.6mm. Multiple spectra were taken for each sample at each shielding level, and the spectra were analyzed using FRAM V3.2. A new parameter set was developed to analyze spectra from zero to 25 mm lead. We will report on the accuracy capabilities of this parameter set.

  9. Plutonium isotopes and 137Cs in Dolon settlement near the Semipalatinsk Nuclear Test Site. About 50 years after the first nuclear weapon testing

    Recent controversies concerning the radiation doses for populations living in the village of Dolon due to the nuclear explosions carried out at the Semipalatinsk Nuclear Test Site (SNTS) have encouraged us to evaluate in more detail the levels and distributions of residual long-lived radionuclides 137Cs and Pu isotopes (238Pu, 239,240Pu) in soils within the village. Soil core samples up to a depth of about 30 cm and/or 100 cm were collected at 25 sites and subjected to analysis of 137Cs and Pu isotopes. The inventories of 137Cs and 239,240Pu were found to be in the wide range of 790-10,310 and 530-14,320 Bq/m2, respectively. Sequential leaching of Pu from the soil showed that more than ca. 80% of the 239,240Pu was not leached by hot digestion with conc. HNO3 + H2O2, indicating the presence of Pu associated with fused silicates. Further, the presence of hot-particles from the Pu contaminants by a-track radiography technique using CR-39 polycarbonate was confirmed in the soil, even at present, after about 50 years from the first nuclear weapon testing. (author)

  10. Comparative analysis of spent fuel isotope composition for VVER-440 compare to VVER-1000 reactors

    Calculations were made for reactor cell of fuel assemblies for VVER-440 and VVER-1000 depending on their manufactory and operation conditions. These cells were composed of the fuel assemblies with the maximum multiplying purpose (enrichment of 4.4% for both reactor types). Concentration as function of burnup of ten most usable isotopes, such as main fuel isotopes U235, U236, U238, Pu239, Pu240, Pu241, as well as some actinides, and fission products, such as Pu242, Am241, Sm149, Sm151 was analyzed

  11. Study on determination of plutonium isotopes in soils from Lublin region (Poland)

    Plutonium isotopes were introduced to the environment mainly as a fallout from nuclear weapons tests carried out intensively in 1954 - 1963 and occasionally later. It was estimated that about 1.2·1016 Bq of 239,240Pu and about 8·10l4Bq of 238Pu was spread in the atmosphere. Another source of plutonium isotopes, which caused local contamination were liquid releases from nuclear facilities, fallout from nuclear-powered satellites burnt up in the atmosphere, accidents of airplanes carrying nuclear missiles or accidental releases such as from Chernobyl in 1986. The latter, which caused the most extensive contamination, especially in Europe, introduced to the atmosphere about 2·1014 Bq of 239,240Pu. Most of plutonium isotopes was spread in the stratosphere, from where it falls down continuously on the Earth surface. Region of Lublin (in eastern part of Poland) has not come yet within monitoring of soil contamination by alpha emitting isotopes like plutonium, while the large contaminations with Chernobyl originated radioisotopes were observed. In our Department we have taken up a study on determination of contamination level of soil by alpha emitting nuclides and, as a result of a cooperation with J. Stefan Institute in Ljubljana (Slovenia), we have developed methods for plutonium isotopes separation

  12. Preparation of a multi-isotope plutonium AMS standard and preliminary results of a first inter-lab comparison

    Dittmann, B.-A.; Dunai, T. J.; Dewald, A.; Heinze, S.; Feuerstein, C.; Strub, E.; Fifield, L. K.; Froehlich, M. B.; Tims, S. G.; Wallner, A.; Christl, M.

    2015-10-01

    The motivation of this work is to establish a new multi-isotope plutonium standard for isotopic ratio measurements with accelerator mass spectrometry (AMS), since stocks of existing solutions are declining. To this end, certified reference materials (CRMs) of each of the individual isotopes 239Pu, 240Pu, 242Pu and 244Pu were obtained from JRC IRMM (Joint Research Center Institute for Reference Materials and Measurements). These certified reference materials (IRMM-081a, IRMM-083, IRMM-043 and IRMM-042a) were diluted with nitric acid and mixed to obtain a stock standard solution with an isotopic ratio of approximately 1.0:1.0:1.0:0.1 (239Pu:240Pu:242Pu:244Pu). From this stock solution, samples were prepared for measurement of the plutonium isotopic composition by AMS. These samples have been measured in a round-robin exercise between the AMS facilities at CologneAMS, at the ANU Canberra and ETH Zurich to verify the isotopic ratio and to demonstrate the reproducibility of the measurements. The results show good agreement both between the different AMS measurements and with the gravimetrically determined nominal ratios.

  13. Equivalence test for sample data of isotopic compositions in PWR spent fuel

    Statistical combination method for previous and JAERI data of isotopic compositions in PWR spent fuel has been investigated. Using the F and T statistical test method, tests for the normality, the homogeneous variance and equivalent mean at a 5 % significance level have been carried out for twenty two isotopes which consist of spent fuel over 30 GWd/tU in burnup. All isotopes except U-238 and Nd-148 seem to be satisfied with the normality. 16 isotopes including U-234 seem to be satisfied with the homogeneous variance. 9 isotopes including U-235 seem to have a equivalent mean. 6 isotopes of U-235, Pu-240, Pu-241, Cs-134, Nd-144 and Sm-148 are appeared to be satisfied simultaneously with 3 alternative test results

  14. Tree-ring isotope records of tropical cyclone activity

    Miller, Dana L.; Mora, Claudia I.; Grissino-Mayer, Henri D.; Mock, Cary J.; Uhle, Maria E.; Sharp, Zachary

    2006-01-01

    The destruction wrought by North Atlantic hurricanes in 2004 and 2005 dramatically emphasizes the need for better understanding of tropical cyclone activity apart from the records provided by meteorological data and historical documentation. We present a 220-year record of oxygen isotope values of α-cellulose in longleaf pine tree rings that preserves anomalously low isotope values in the latewood portion of the ring in years corresponding with known 19th and 20th century landfalling/near-coa...

  15. {\\alpha}-accompanied cold ternary fission of $^{238-244}$Pu isotopes in equatorial and collinear configuration

    Santhosh, K P; Priyanka, B

    2015-01-01

    The cold ternary fission of $^{238}$Pu, $^{240}$Pu, $^{242}$Pu and $^{244}$Pu isotopes, with $^{4}$He as light charged particle, in equatorial and collinear configuration has been studied within the Unified ternary fission model (UTFM). The fragment combination $^{100}$Zr+$^{4}$He+$^{134}$Te possessing the near doubly magic nuclei $^{134}$Te (N=82, Z=52) gives the highest yield in the alpha accompanied ternary fission of $^{238}$Pu. For the alpha accompanied ternary fission of $^{240}$Pu, $^{242}$Pu and $^{244}$Pu isotopes, the highest yield was found for the fragment combination with doubly magic nuclei $^{132}$Sn (N=82, Z=50) as the heavier fragment. The deformation and orientation of fragments have also been taken into account for the alpha accompanied ternary fission of $^{238-244}$Pu isotopes, and it has been found that in addition to closed shell effect, ground state deformation also plays an important role in determining the isotopic yield in the ternary fission process. The emission probability and ki...

  16. Fallout Radioactivity in Some Egyptian Lakes Bottom Sediments

    As a part of the Egyptian environmental radioactivity monitoring program, the fallout radioactivity levels in Qarun, Bardawill and Ed ku lakes bottom sediments have been measured. The specific activities of 137Cs were measured using gamma ray spectrometer based on Hyper pure germanium detector. The specific activities of plutonium isotopes(238Pu, 239+240Pu and 241Pu) were measured using alpha spectrometry based on surface battier detectors and liquid scintillation spectrometry after radiochemical separation. The activity ratios 239+240Pu/137Cs, 239+240Pu/241Pu, and 238Pu/ 239+240Pu were calculated. The results seemed to confirm that fallout radioactivity is mainly due to nuclear weapons testing fallout

  17. Measurement of plutonium isotopic composition by gamma-ray spectroscopy

    The technology of the analysis of plutonium isotopic ratio is independent of the measurement geometry and applicable to samples of physical and chemical composition. Three standard plutonium samples were measured in the HPGe system. The results showed that CRM 136 and CRM 137 containing 238Pu(0.223%) and 238Pu(0.268%) were 18.4% and 14.2% error and CRM 138 of 238Pu(0.01%) was 76% error. However the analysis represented less than 1.6% and 9% error in the three standard samples of highly involved 239Pu and 240Pu. Therefore, gamma-ray spectroscopy is very effective in the plutonium isotope analysis, having greater than 10% in content

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

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

    2004-07-01

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

  19. Use of plutonium isotope activity ratios in dating recent sediments

    The majority of plutonium presently in the biosphere has come from the testing of nuclear devices. In the early 1950s, the Pu-238/239+240 activity ratio of fallout debris was > 0.04; in the more extensive test series of 1961 to 1962, the Pu-238/239+240 activity ratios were quite consistent at 0.02 to 0.03 and maximum fallout delivery occurred in mid-1963. A significant perturbation in Pu isotope activity ratios occurred in mid-1966 with the deposition of Pu-238 from the SNAP-9A reentry and burn-up. Recently deposited sediments have recorded these events and where accumulation rates are rapid (> 1 cm/y), changes in Pu isotope activity ratios can be used as a geochronological tool

  20. Total beta activity, 137Cs and 90Sr in surface air in northern Finland in 1963

    Air filter samples collected at Sodankylae(67 22' N, 26 39' E) were analyzed to determine concentrations of 137Cs and 90Sr in surface air in northern Finland in 1963. Previously, activity concentrations of Pu isotopes have been determined from the same filters. Activity concentrations of 137Cs and 90Sr in surface air were 3-13800 ± 2700 μBq/m3 and 3-5340 ± 290 μBq/m3, respectively. Air concentrations of 137Cs and 90Sr varied seasonally with a maximum in spring due to the springtime enhanced transportation of air masses with radioactive aerosols from the stratosphere to the troposphere. Activity ratios 90Sr/239+240Pu and 90Sr/137Cs were 6.9 ± 0.8-75 ± 5 and 0.08 ± 0.03-1.46 ± 0.51, respectively. The median value for the 90Sr/137Cs ratio (0.508) indicates contamination from global nuclear test fallout. An air mass back trajectory analysis suggests that no direct transport of radioactivity from the Novaya Zemlya test site to northern Finland occurred in 1963. (orig.)

  1. Origin and release date assessment of environmental plutonium by isotopic composition

    Varga, Zsolt [Hungarian Academy of Sciences, Radiation Safety Department, Institute of Isotopes, Budapest (Hungary)

    2007-10-15

    The origin and release date of environmental plutonium have been assessed by the measurement of plutonium and americium isotopic composition. The applicability and sensitivity of different plutonium isotope ratios, {sup 240}Pu/{sup 239}Pu and {sup 241}Pu/{sup 239}Pu measured by inductively coupled plasma sector field mass spectrometry and {sup 238}Pu/{sup 239}Pu analysed by alpha spectrometry, have been evaluated for origin determination in several types of environmental samples. With use of mixing models the contribution of different sources (e.g. global fallout or Chernobyl) can be calculated. By the measurement of the {sup 241}Am/{sup 241}Pu isotope ratio, the release date (i.e. formation of {sup 241}Pu by irradiation) can be estimated in environmental samples, which is an important parameter to distinguish recent plutonium release from previous (e.g. Chernobyl) emissions. (orig.)

  2. Origin and release date assessment of environmental plutonium by isotopic composition

    The origin and release date of environmental plutonium have been assessed by the measurement of plutonium and americium isotopic composition. The applicability and sensitivity of different plutonium isotope ratios, 240Pu/239Pu and 241Pu/239Pu measured by inductively coupled plasma sector field mass spectrometry and 238Pu/239Pu analysed by alpha spectrometry, have been evaluated for origin determination in several types of environmental samples. With use of mixing models the contribution of different sources (e.g. global fallout or Chernobyl) can be calculated. By the measurement of the 241Am/241Pu isotope ratio, the release date (i.e. formation of 241Pu by irradiation) can be estimated in environmental samples, which is an important parameter to distinguish recent plutonium release from previous (e.g. Chernobyl) emissions. (orig.)

  3. Survey of plutonium and uranium atom ratios and activity levels in Mortandad Canyon

    Gallaher, B.M.; Benjamin, T.M.; Rokop, D.J.; Stoker, A.K.

    1997-09-22

    For more than three decades Mortandad Canyon has been the primary release area of treated liquid radioactive waste from the Los Alamos National Laboratory (Laboratory). In this survey, six water samples and seven stream sediment samples collected in Mortandad Canyon were analyzed by thermal ionization mass spectrometry (TIMS) to determine the plutonium and uranium activity levels and atom ratios. Be measuring the {sup 240}Pu/{sup 239}Pu atom ratios, the Laboratory plutonium component was evaluated relative to that from global fallout. Measurements of the relative abundance of {sup 235}U and {sup 236}U were also used to identify non-natural components. The survey results indicate the Laboratory plutonium and uranium concentrations in waters and sediments decrease relatively rapidly with distance downstream from the major industrial sources. Plutonium concentrations in shallow alluvial groundwater decrease by approximately 1000 fold along a 3000 ft distance. At the Laboratory downstream boundary, total plutonium and uranium concentrations were generally within regional background ranges previously reported. Laboratory derived plutonium is readily distinguished from global fallout in on-site waters and sediments. The isotopic ratio data indicates off-site migration of trace levels of Laboratory plutonium in stream sediments to distances approximately two miles downstream of the Laboratory boundary.

  4. Root activity evaluation in tree crops using isotopic techniques

    This paper discusses the methdology used to evalute root activity of the crops utilizing the technique of soil injection with solutions marked with isotopes. Some of the experimental data obtained with coffee, citrus and oil palm are also presented. Ovel all, these tree crops present a higher root activity in soil layers close to the surface (0-20 cm) and to a distance from the trunk which varies with age, season and variety. The most important conclusions are: 1. The isotope injection technique using 32P, 15N, or 85Rb, allow direct and reliable determination of root activity in these tree crops. 2. Root activity of three crops depends on age of the tree, variety, moisture content of the soil and soil type. 3. Soil moisture is the most influencial factor affecting root activity. This is turn depends on the irrigation method employed. 4. From the practical view point, the best distance from the trunk to apply fertilizer in the one wich has highest root activity closest to the soil surface

  5. Pu isotopes in the western North Pacific Ocean before the accident at Fukushima Dai-ichi Nuclear Power Station

    Yamada, M.; Zheng, J.; Aono, T.

    2011-12-01

    Anthropogenic radionuclides such as Pu-239 (half-life: 24100 yr), Pu-240 (half-life: 6560 yr) and Pu-241 (half-life: 14.325 yr) mainly have been released into the environment as the result of atmospheric nuclear weapons testing. In the North Pacific Ocean, two distinct sources of Pu isotopes can be identified; i.e., the global stratospheric fallout and close-in tropospheric fallout from nuclear weapons testing at the Pacific Proving Grounds in the Marshall Islands. The atom ratio of Pu-240/Pu-239 is a powerful fingerprint to identify the sources of Pu in the ocean. The Pu-240/Pu-239 atom ratios in seawater and marine sediment samples collected in the western North Pacific before the accident at Fukushima Dai-ichi Nuclear Power Station will provide useful background data for understanding the process controlling Pu transport and for distinguishing future Pu sources. The atom ratios of Pu-240/Pu-239 in water columns from the Yamato and Tsushima Basins in the Japan Sea were significantly higher than the mean global fallout ratio of 0.18; however, there were no temporal variation of atom ratios during the period from 1984 to 1993 in the Japan Sea. The total Pu-239+240 inventories in the whole water columns were approximately doubled during the period from 1984 to 1993 in the two basins. The atom ratio of Pu-240/Pu-239 in surface water from Sagami Bay, western North Pacific Ocean, was 0.224 and showed no notable variation from the surface to the bottom with the mean atom ratio being 0.234. The atom ratios for the Pacific coast, near the Rokkasho nuclear fuel reprocessing plant, were approximately the same as the 0.224 ratio obtained from Sagami Bay, western North Pacific margin. The atom ratios in the surficial sediments from Sagami Bay ranged from 0.229 to 0.247. The mean atom ratio in the sediment columns in the East China Sea ranged from 0.248 for the Changjiang estuary to 0.268 for the shelf edge. The observed atom ratios were significantly higher than the mean

  6. 福岛核事故向环境释放的 Pu研究进展%Plutonium Isotopes Released f rom Fukushima Daiichi Nuclear Power Plant Accident into Environment

    倪有意; 卜文庭; 郭秋菊; 胡丹; 许宏

    2015-01-01

    On March 11 , 2011 , a catastrophic tsunami induced by a magnitude 9.0 earthquake caused the terrible Fukushima Daiichi Nuclear Power Plant (FDNPP) acci‐dent ,leading to the release of a large amount of radionuclides into the environment .T he published studies on plutonium isotopes in the environment after the FDNPP accident were reviewed in this paper .The total atmospheric released amounts of Pu from the FDNPP accident were estimated to be 109 Bq ,that is only 1/10 000 of that released from the Chernobyl accident .The Pu isotopes were released from the damaged reactors ,not from the spent fuel pools in the FDNPP .The Pu isotopic ratios (240 Pu/239 Pu ,241 Pu/239 Pu) and activity ratios of A(238 Pu)/A(239+ 240 Pu) were significantly different from that of global fallout ,serving as powerful fingerprints for Pu source identification .To date , the plutonium isotopes from the accident in the terrestrial environment within the 30 km zone around the FDNPP site have been widely observed and there are no strong positive correlations between the Pu isotopes contamination levels and the distances from the FDNPP site .The influence of the FDNPP accident on Pu distributions in the marine environment is limited .No detectable Pu contamination from the accident is observed even in the near coastal (5 km off the FDNPP site) marine sediments .%福岛核事故向环境释放的放射性核素中包含了锕系元素Pu ,其中以极毒组的239 Pu、240 Pu和高毒组的241 Pu为主。本文总结并分析了针对福岛核事故向环境释放的 Pu的相关研究。据估计,福岛核事故向环境中排放的239+240 Pu总量约为109 Bq ,是切尔诺贝利核事故排放量的万分之一。此次事故排放的Pu同位素原子比(240 Pu/239 Pu和241 Pu/239 Pu)及活度比(A (238 Pu)/A (239+240 Pu))明显异于全球沉降值,可作为事故中Pu溯源的判定依据。事故所排放的Pu全部来源于核电站1~3号反应堆堆芯

  7. Performance of isotope correlations for the estimate of 242Pu

    Full text: The lack of a gamma-ray signature from 242Pu represents an Achilles heel for many plutonium isotope abundance measurements made by high-resolution gamma spectrometry (HRGS). This holds in particular for plutonium materials containing a significant fraction of this isotope. The problem is partially solved through the application of isotope correlations estimating the relative abundance of 242Pu from relations to ratios of other plutonium isotopes measurable by HRGS. In the mid of the nineties a new type of isotope correlation had been proposed for LWR plutonium based on the following relation: 242Pu/239Pu = C0·[238Pu/239Pu]c1 · [240Pu/239Pu]c2 with recommended coefficients C0, C1 and C2 for PWR and BWR fuels, respectively. We have adopted this type of correlation for the routine analysis of safeguards samples in the Euratom On-Site Laboratories and in the Institute for Transuranium Elements. In order to cover the full range of plutonium materials received for analysis, the application of the above correlation has been also extended to AGR and Magnox-type of plutonium. The differing sets of coefficients C0, C1 and C2 approximating best the correlation for the additional types of materials were determined from a set of reference isotopic data. Since in many instances the origin and the type of the plutonium are not known a priori, criteria for categorization were established helping to select the appropriate isotope correlation. Parametric plots of the ratios 238Pu/239Pu versus 240Pu/239Pu generally allow to discern unambiguously Magnox, AGR and LWR plutonium, and to some extent also BWR and PWR plutonium, as long as a mixing of the respective plutonium materials has not occurred. With this kind of categorization implemented in the routine analysis the performance of the 242Pu estimate is substantially improving in most cases. Performance data for 242Pu in particular, and for plutonium isotope abundance measurements by HRGS in general, as derived from a

  8. Examining Changes in Radioxenon Isotope Activity Ratios during Subsurface Transport

    Annewandter, Robert

    2014-05-01

    The Non-Proliferation Experiment (NPE) has demonstrated and modelled the usefulness of barometric pumping induced gas transport and subsequent soil gas sampling during On-Site inspections. Generally, gas transport has been widely studied with different numerical codes. However, gas transport of radioxenons and radioiodines in the post-detonation regime and their possible fractionation is still neglected in the open peer-reviewed literature. Atmospheric concentrations of the radioxenons Xe-135, Xe-133m, Xe-133 and Xe-131m can be used to discriminate between civilian releases (nuclear power plants or medical isotope facilities), and nuclear explosion sources. It is based on the multiple isotopic activity ratio method. Yet it is not clear whether subsurface migration of the radionuclides, with eventual release into the atmosphere, can affect the activity ratios due to fractionation. Fractionation can be caused by different mass diffusivities due to mass differences between the radionuclides. Cyclical changes in atmospheric pressure can drive subsurface gas transport. This barometric pumping phenomenon causes an oscillatoric flow in upward trending fractures or highly conductive faults which, combined with diffusion into the porous matrix, leads to a net transport of gaseous components - a so-called ratcheting effect. We use a general purpose reservoir simulator (Complex System Modelling Platform, CSMP++) which is recognized by the oil industry as leading in Discrete Fracture-Matrix (DFM) simulations. It has been applied in a range of fields such as deep geothermal systems, three-phase black oil simulations, fracture propagation in fractured, porous media, and Navier-Stokes pore-scale modelling among others. It is specifically designed to account for structurally complex geologic situation of fractured, porous media. Parabolic differential equations are solved by a continuous Galerkin finite-element method, hyperbolic differential equations by a complementary finite

  9. Measurement of the activity of electron capturing isotopes

    In order to measure precisely the activity of electron capturing isotopes, an equipment was constructed for the detection the X-photons, the Auger- and the conversing electrons by a high-pressure, gas-flow 4π proportional counter. The proportional counter and the NaI(Tl) scintillation counter are placed in a common lead-shielding, thus, the equipment is suited for the measurement of radioisotopes decaying in coincidence. The structure of the proportional counter and of the pressure-control system are detailed. As an example, the energy spectra of a 109Cd solution, taken at different pressures, are published. At a pressure of 1.1 MPa the 3 peaks are well separated. The results of an international test, in which the radioactivity of a 57Co sample was determined, are published, too. (L.E.)

  10. Calculation of cross sections for heavy isotopes

    In the present work an integrated system of codes for basic neutron data evaluation were assembled and built. Complete evaluations for the isotopes 240Pu, 241Pu, 242Pu and 238Pu were performed. The following cross sections: total, elastic, radiative capture, fission, total inelastic, partial inelastic, (n,2n), (n,3n) and differential elastic were evaluated as well as the average number of neutrons per neutron-induced fission and the average elastic scattering cosine in the lab system.The data for the plutonium isotopes were incorporated into the German KEDAK file. A method was developed for calculating the energy distributions of the second and third secondary neutrons from the A(n,2n) and (n,3n) reactions in the framework of the compound nucleus theory, and utilizing the nuclear data of the nuclei A, A-1, A-2. This method was used to generate the 238U secondary neutron energy distributions in the incident neutron energy range of 6 to 15 MeV. A nuclear data evaluation for 237U in the resolved inelastic scattering range (10-700 keV) was performed. The compound elastic and partial inelastic scattering cross sections were used in the 238U secondary neutron energy distribution calculations. (B.G.)

  11. Generation of an actinide isotopes cross section set for fast reactor calculations using data from ENDL and ENDF/B-IV

    A Bondarenko format 25-group cross section set of actinide isotopes was generated for the fuel cycle evaluation and the incineration study in fast reactor systems. Evaluated Nuclear Data Library of Lawrence Livermore Laboratory (U.S.) was used as the source data. The actinide isotopes treated are the following 28: Th-232, U-233, U-234, U-235, U-236, U-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Pu-243, Am-241, Am-242, Am-243, Cm-242, Cm-243, Cm-245, Cm-246, Cm-247, Cm-248, Bk-249, Cf-249, Cf-250, Cf-251, Cf-252 and a pseudo-fission product. ENDF/B-IV was used for U-238. The set was then collapsed to one energy group using a large LMFBR core spectrum for the comparison with other one-group sets. (author)

  12. Intercomparison of Activity Measurement of Isotopes 57Co5 and 131I (II)

    Intercomparison of activity measurement of isotopes 57Co and 131I between PSPKR-BATAN and several hospitals in Indonesia, PPTN-BATAN Bandung as well as PPR-BATAN Serpong was carried out. Both isotopes used have been standardized at PSPKR-BATAN. Each isotope consisted of 2 samples with different activities, where the weight of each sample was about 3 gram + 0.2%. To know the performance of dose calibrator belong to the hospitals, these standardized isotopes were measured. The differences of the activity measurement for 57Co were vary from 0.13 to 32 %, and for 131I from 0.3 to 50 %. In general, deviation of dose calibrator using Geiger Muller was relatively greater than that of ionization chamber

  13. A cyclic neutron activation system using an isotopic neutron source for the measurement of short-lived isotopes

    The design and construction of an activation analysis system using an isotopic neutron source which allows the measurement of prompt and delay gamma-rays, in conventional activation and cyclic activation modes, is briefly described with emphasis laid on its flexibility, transportability and low cost. Photon spectra obtained from the irradiation of large samples under prompt, delay and cyclic conditions using both NaI(Tl) and Ge(Li) detectors are presented and described with respect to 'in-vivo' neutron activation analysis and the measurement of N, O, Na, P, Cl and Cd. It is pointed out that, despite the attractive possibility of measuring Se in liver, 'in-vivo', by cyclic activation analysis, the system may potentially prove a very useful tool for industrial and other non-medical applications. (author)

  14. Non-destructive measurement of carbonic anhydrase activity and the oxygen isotope composition of soil water

    Jones, Sam; Sauze, Joana; Ogée, Jérôme; Wohl, Steven; Bosc, Alexandre; Wingate, Lisa

    2016-04-01

    Carbonic anhydrases are a group of metalloenzymes that catalyse the hydration of aqueous carbon dioxide (CO2). The expression of carbonic anhydrase by bacteria, archaea and eukarya has been linked to a variety of important biological processes including pH regulation, substrate supply and biomineralisation. As oxygen isotopes are exchanged between CO2 and water during hydration, the presence of carbonic anhydrase in plants and soil organisms also influences the oxygen isotope budget of atmospheric CO2. Leaf and soil water pools have distinct oxygen isotope compositions, owing to differences in pool sizes and evaporation rates, which are imparted on CO2during hydration. These differences in the isotopic signature of CO2 interacting with leaves and soil can be used to partition the contribution of photosynthesis and soil respiration to net terrestrial CO2 exchange. However, this relies on our knowledge of soil carbonic anhydrase activity and currently, the prevalence and function of these enzymes in soils is poorly understood. Isotopic approaches used to estimate soil carbonic anhydrase activity typically involve the inversion of models describing the oxygen isotope composition of CO2 fluxes to solve for the apparent, potentially catalysed, rate of oxygen exchange during hydration. This requires information about the composition of CO2 in isotopic equilibrium with soil water obtained from destructive, depth-resolved soil water sampling. This can represent a significant challenge in data collection given the considerable potential for spatial and temporal variability in the isotopic composition of soil water and limited a priori information with respect to the appropriate sampling resolution and depth. We investigated whether we could circumvent this requirement by constraining carbonic anhydrase activity and the composition of soil water in isotopic equilibrium with CO2 by solving simultaneously the mass balance for two soil CO2 steady states differing only in the

  15. Performance of isotope correlations for the estimate of 242Pu

    The lack of a gamma-ray signature from 242 Pu represents an Achilles heel for many plutonium isotope abundance measurements made by high-resolution gamma spectrometry (HRGS). This holds in particular for plutonium materials containing a significant fraction of this isotope. The problem is partially solved through the application of isotope correlations estimating the relative abundance of 242 Pu from relations to ratios of other plutonium isotopes measurable by HRGS. In the mid of the nineties a new type of isotope correlation had been proposed for LWR plutonium with the recommended coefficients for PWR and BWR fuels. This type of correlation was adopted for the routine analysis of safeguards samples in the Euratom On-Site Laboratories and in the Institute for Transuranium Elements. In order to cover the full range of plutonium materials received for analysis, the application of the above correlation has been also extended to AGR and Magnox-type of plutonium with different sets of coefficients approximating best the correlation for the additional types of materials were determined from a set of reference isotopic data. Since in many instances the origin and the type of the plutonium are not known a priori, criteria for categorization were established helping to select the appropriate isotope correlation. Parametric plots of the ratios 238 Pu/239 Pu versus 240 Pu/239 Pu generally allow to discern unambiguously Magnox, AGR and LWR plutonium, and to some extent also BWR and PWR plutonium, as long as a mixing of the respective plutonium materials has not occurred. With this kind of categorization implemented in the routine analysis the performance of the 242 Pu estimate is substantially improving in most cases. Performance data for 242 Pu in particular, and for plutonium isotope abundance measurements by HRGS in general, as derived from a larger set of measurement data are presented and discussed in terms of their impact on the interpretation of passive neutron

  16. ZZ AMZ, 70-Group 40 Isotope Multigroup Library for Fast Reactor Calculation

    1 - Description of program or function: format: EXPANDA; number of groups: 70-group library of multigroup constants; nuclides: H-1, Be-9, B-10, B-11, C-12, O-16, N-23, Mg, Al-27, Si, Ti, V, Cr, Mn-55, Fe, Ni, Cu, Ga, Zr, Nb-93, Mo, In-115, Sn, Pb, Th-232, Pa-233, U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, and lumped fission products of U-233, U-235, Pu-239. origin: ENDF/B-IV and ENDF/B-V; weighting spectrum: Fission products inventories for BBR reactor at 360 and 600 days of irradiation were calculated and used as weighting function. AMZ is a 70-group library of multigroup constants for the fast reactor nuclear design code EXPANDA. Data is stored for three temperatures (300 K, 900 K, 2100 K) and for seven background cross sections. The following isotopes are available: H1, Be9, B10, B11, C12, O16, N23, Mg, Al27, Si, Ti, V, Cr, Mn55, Fe, Ni, Cu, Ga, Zr, Nb93, Mo, In115, Sn, Pb, Th232, Pa233, U233, U234, U235, U236, U238, Pu238, Pu239, Pu240, Pu241, Pu242, Am241, and lumped fission products of U233, U235, Pu239. 2 - Method of solution: Nuclear cross sections, transfer matrices, and self-shielding factors were generated from ENDF/B-IV data using the codes NJOY (PSR-0171) and RGENDF

  17. Study on plutonium isotopic analysis in environmental samples

    A method for determination of plutonium isotope ratio in environmental samples was investigated in our laboratory. Plutonium was separated with complex matrix and purified by using TEVA extraction chromatography resin, and determined by MC-ICP-MS. The elution of Pu from TEVA column was tested. Plutonium could be eluted from TEVA column effectively by 0.025mol·l-1 H2C2O4-0.15mol·l-1HNO3 or 10-2 mol·l-1 ascorbic acid- 0.2 mol·l-1HNO3. For one TEVA column, the decontamination factors of main environmental matrix , such as Na, K, Ca, Al, Fe, Mg, were between 104-105, and the concentration of total cation ions in the final elution was less than 10 μg·g-1, which could be determined by MC-ICP-MS directly. The decontamination of U, Th and Am was also examined, DFU/Pu=1.97x103, DFTh/Pu=7.19 x 104, DFAm/Pu=1.52x104 were obtained. The chemical recovery of plutonium during the whole process was ∼ 30%. Because of the tailing of 238U and the formation of 238UH+ while the determination of plutonium isotope by MS, it was not enough for the decontamination of uranium by using one TEVA column. A UTEVA column was needed before the solution loading in the TEVA resin. The decontamination factor of uranium could reach 1.33x106. The detection limit of Pu by MC-ICP-MS was about 2.5 fg·ml-1. The influence of U on the determination of plutonium isotope ratio was also examined. For the solution containing less than 1 ng·g-1 uranium, Aridus sample introduction system was adopted to improve the sensitivity. Meinhard PFA nebulizer was used for solutions of high uranium concentration (1- 500 ng·g-1). The results show that, the 238UH+/U+ is about 8.9x10-5 for the high content of uranium, and about 3.6x10-4 for the low content. According to the method mentioned above, two IAEA reference materials, IAEA-368 and SOIL-6 were analyzed. Purified Pu fractions were obtained by using UTEVA+TEVA extraction chromatography; 240Pu/239Pu were determined by MC-ICP-MS. The results were shown. Ocean

  18. Study on plutonium isotopic analysis in environmental samples

    A method for determination of plutonium isotope ratio in environmental samples was investigated in our laboratory. Plutonium was separated with complex matrix and purified by using TEVA extraction chromatography resin, and determined by MC-ICP-MS. The elution of Pu from TEVA column was tested. Plutonium could be eluted from TEVA column effectively by 0.025mol·l-1 H2C2O4-0.15mol·l-1HNO3 or 10-2 mol·l-1 ascorbic acid-0.2mol·l-1HNO3. For one TEVA column, the decontamination factors of main environmental matrix , such as Na, K, Ca, Al, Fe, Mg, were between 104-105, and the concentration of total cation ions in the final elution was less than 10 μg·g-1, which could be determined by MC-ICP-MS directly. The decontamination of U, Th and Am was also examined, DFU/Pu=1.97x103,DFTh/Pu=7.19x104,DFAm/Pu=1.52x104 were obtained. The chemical recovery of plutonium during the whole process was ∼30%. Because of the tailing of 238U and the formation of 238UH+ while the determination of plutonium isotope by MS, it was not enough for the decontamination of uranium by using one TEVA column. A UTEVA column was needed before the solution loading in the TEVA resin. The decontamination factor of uranium could reach 1.33x106. The detection limit of Pu by MC-ICP-MS was about 2.5 fg·ml-1. The influence of U on the determination of plutonium isotope ratio was also examined. For the solution containing less than 1 ng·g-1 uranium, Aridus sample introduction system was adopted to improve the sensitivity. Meinhard PFA nebulizer was used for solutions of high uranium concentration(1-500 ng·g-1). The results show that, the 238UH+/U+ is about 8.9x10-5 for the high content of uranium, and about 3.6x10-4 for the low content. According to the method mentioned above, two IAEA reference materials, IAEA-368 and SOIL-6 were analyzed. Purified Pu fractions were obtained by using UTEVA+TEVA extraction chromatography; 240Pu/239Pu were determined by MC-ICP-MS. The results were showed in table 1. Ocean

  19. Antimony isotopic composition in river waters affected by ancient mining activity.

    Resongles, Eléonore; Freydier, Rémi; Casiot, Corinne; Viers, Jérôme; Chmeleff, Jérôme; Elbaz-Poulichet, Françoise

    2015-11-01

    In this study, antimony (Sb) isotopic composition was determined in natural water samples collected along two hydrosystems impacted by historical mining activities: the upper Orb River and the Gardon River watershed (SE, France). Antimony isotope ratio was measured by HG-MC-ICP-MS (Hydride Generation Multi-Collector Inductively Coupled Plasma Mass Spectrometer) after a preconcentration and purification step using a new thiol-cellulose powder (TCP) procedure. The external reproducibility obtained for δ(123)Sb measurements of our in-house Sb isotopic standard solution and a certified reference freshwater was 0.06‰ (2σ). Significant isotopic variations were evident in surface waters from the upper Orb River (-0.06‰≤δ(123)Sb≤+0.11‰) and from the Gardon River watershed (+0.27‰≤δ(123)Sb≤+0.83‰). In particular, streams that drained different former mining sites exploited for Sb or Pb-Zn exhibited contrasted Sb isotopic signature, that may be related to various biogeochemical processes occurring during Sb transfer from rocks, mine wastes and sediments to the water compartment. Nevertheless, Sb isotopic composition appeared to be stable along the Gardon River, which might be attributed to the conservative transport of Sb at distance from mine-impacted streams, due to the relative mobile behavior of Sb(V) in natural oxic waters. This study suggests that Sb isotopic composition could be a useful tool to track pollution sources and/or biogeochemical processes in hydrologic systems. PMID:26452900

  20. DU ammunition and the environment: Isotopic concentrations of U and Pu and DU particle size distribution in soil samples

    The work summarises the experimental studies conducted by the IAEA Seibersdorf Laboratories and other collaborating groups on soil samples collected in Kosovo locations where DU ammunition was expended during the 1999 Balkan conflict. The samples were analysed for their content in uranium and plutonium isotopes (234U, 235U, 236U, 238U, 238Pu, 239+240Pu). The analyses were conducted by gamma spectrometry (235U, 238U), alpha spectrometry (238Pu, 239+240Pu), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) (234U, 235U, 236U, 238U) and Accelerator Mass Spectrometry (AMS) (235U, 238U). The results indicated that whenever the U concentration exceeded the normal environmental values (approx. 2 to 3 mg/kg) the increase was due to DU. 236U was also present in the released DU at the constant ratio 236U (mg/kg)/238U (mg/kg) = 2.6 x 10-5 , indicating that the DU used in the ammunition was from a batch that had been irradiated and then reprocessed. The plutonium concentration in the soil (undisturbed) was about 1 Bq/kg. From the measured 238Pu/239+240Pu it could be attributed to the fallout of the nuclear weapon tests of the sixties (no appreciable contribution from DU). Selected soil samples were also investigated by secondary ion mass spectrometry (SIMS), X-ray fluorescence imaging using a micro-beam (μ-XRF) and scanning electron microscopy equipped with an energy dispersive X-ray fluorescence detector (SEM-EDXRF). This permitted to identify the presence of small DU particles and measure their size distribution. The results, although not permitting any legitimate extrapolation to all the sites hit by the DU rounds, indicated that there can be 'spots' where hundreds of thousand particles may be present in a few milligrams of DU contaminated soil. The particle size distribution showed that most of the DU particles were < 5 μm in diameter and more than 50 % of the particles had a diameter < 1.5 μm. Knowledge on DU particles is needed as a base for the assessment of

  1. Distribution and source of 129I, 239,240Pu, 137Cs in the environment of Lithuania

    Ezerinskis, Z.; Hou, Xiaolin; Druteikiene, R.;

    2016-01-01

    Fifty five soil samples collected in the Lithuania teritory in 2011 and 2012 were analyzed for 129I, 137Cs and Pu isotopes in order to investigate the level and distribution of artificial radioactivity in Lithuania. The activity and atomic ratio of 238Pu/239,240Pu, 129I/127I and 131I/137Cs were u...

  2. Chlorine Isotopes: As a Possible Tracer of Fluid/Bio-Activities on Mars and a Progress Report on Chlorine Isotope Analysis by TIMs

    Nakamura, N.; Nyquist, L.E.; Reese, Y.; Shih, C-Y.; Numata, M.; Fujitani, T.; Okano, O.

    2009-01-01

    Significantly large mass fractionations between chlorine isotopes (Cl-35, Cl-37) have been reported for terrestrial materials including both geological samples and laboratory materials. Also, the chlorine isotopic composition can be used as a tracer for early solar system processes. Moreover, chlorine is ubiquitous on the Martian surface. Typical chlorine abundances in Gusev soils are approx.0.5 %. The global surface average chlorine abundance also is approx.0.5 %. Striking variations among outcrop rocks at Meridiani were reported with some chlorine abundances as high as approx.2%. Characterizing conditions under which chlorine isotopic fractionation may occur is clearly of interest to planetary science. Thus, we have initiated development of a chlorine isotopic analysis technique using TIMS at NASA-JSC. We present here a progress report on the current status of development at JSC and discuss the possible application of chlorine isotopic analysis to Martian meteorites in a search for fluid- and possibly biological activity on Mars.

  3. On the substantion of permissible concentrations of plutonium isotopes in the water of fresh water and sea water NPP cooling reservoirs

    Substantiation of maximum permissible concentration (PC) of plutonium isotopes (238Pu, 239Pu, 240Pu) in fresh and sea water cooling reservoirs of NPP with fast neutron reactors is given. The main criterion when calculating permissible plutonium content in water of surface reservoirs is the requirement not to exceed the established limits for radiation doses to persons resulted from water use. Data on coefficients of plutonium concentration in sea and fresh water hydrobionts are presented as well as on plutonium PC in water of fresh and sea water cooling reservoirs and bottom sediments of sea water cooling reservoirs. It is shown that doses to critical groups of population doesn't exceed potentially hazardous levels due to plutonium intake through food chains. But the calculation being carried out further should be corrected

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

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

    2010-01-01

    This paper reports an automated analytical method for rapid and simultaneous determination of plutonium isotopes (239Pu and 240Pu) and neptunium (237Np) in environmental samples. An extraction chromatographic column packed with TrisKem TEVA® resin was incorporated in a sequential injection (SI......) system for the isolation of plutonium and neptunium from matrix elements and interfering nuclides. Valence adjustment is a crucial step to ensure the same chemical behavior of plutonium and neptunium onto the TEVA column and consequently to accomplish their simultaneous separation and detection. Distinct...... procedures were investigated and compared for the adjustment of oxidation states of plutonium and neptunium to Pu(IV) and Np(IV), respectively. A two-step protocol using sulfite and concentrated nitric acid as redox reagents was proven to be the most effective method. The analytical results for both...

  5. Reconstruction of the isotope activity content of heterogeneous nuclear waste drums

    Radioactive waste must be characterized in order to verify its conformance with national regulations for intermediate storage or its disposal. Segmented gamma scanning (SGS) is a most widely applied non-destructive analytical technique for the characterization of radioactive waste drums. The isotope specific activity content is generally calculated assuming a homogeneous matrix and activity distribution for each measured drum segment. However, real radioactive waste drums exhibit non-uniform isotope and density distributions most affecting the reliability and accuracy of activities reconstruction in SGS. The presence of internal shielding structures in the waste drum contributes generally to a strong underestimation of the activity and this in particular for radioactive sources emitting low energy gamma-rays independently of their spatial distribution. In this work we present an improved method to quantify the activity of spatially concentrated gamma-emitting isotopes (point sources or hot spots) in heterogeneous waste drums with internal shielding structures. The isotope activity is reconstructed by numerical simulations and fits of the angular dependent count rate distribution recorded during the drum rotation in SGS using an analytical expression derived from a geometric model. First results of the improved method and enhancements of this method are shown and are compared to each other as well as to the conventional method which assumes a homogeneous matrix and activity distribution. It is shown that the new model improves the accuracy and the reliability of the activity reconstruction in SGS and that the presented algorithm is suitable with respect to the framework requirement of industrial application. - Highlights: ► The reconstruction of the isotope specific activity content relies on an easy analytical model motivated by basic physics. ► The reconstruction of the isotope specific activity content is based on the assumption that activity can be

  6. Separation Of Uranium And Plutonium Isotopes For Measurement By Multi Collector Inductively Coupled Plasma Mass Spectroscopy

    Martinelli, R E; Hamilton, T F; Williams, R W; Kehl, S R

    2009-03-29

    Uranium (U) and plutonium (Pu) isotopes in coral soils, contaminated by nuclear weapons testing in the northern Marshall Islands, were isolated by ion-exchange chromatography and analyzed by mass spectrometry. The soil samples were spiked with {sup 233}U and {sup 242}Pu tracers, dissolved in minerals acids, and U and Pu isotopes isolated and purified on commercially available ion-exchange columns. The ion-exchange technique employed a TEVA{reg_sign} column coupled to a UTEVA{reg_sign} column. U and Pu isotope fractions were then further isolated using separate elution schemes, and the purified fractions containing U and Pu isotopes analyzed sequentially using multi-collector inductively coupled plasma mass spectrometer (MCICP-MS). High precision measurements of {sup 234}U/{sup 235}U, {sup 238}U/{sup 235}U, {sup 236}U/{sup 235}U, and {sup 240}Pu/{sup 239}Pu in soil samples were attained using the described methodology and instrumentation, and provide a basis for conducting more detailed assessments of the behavior and transfer of uranium and plutonium in the environment.

  7. A study of in-line plutonium isotopic analysis for gaseous plutonium hexafluoride

    In-line plutonium isotopic analysis of gaseous plutonium hexafluoride (PuF6) is very important for process control and special nuclear material accountability in any plutonium-isotope-separation process that requires a gaseous phase. Although much effort had been devoted to analyze arbitrary plutonium samples, no isotopic analysis had been done on gaseous PuF6 samples. We have initiated a study on the use of a high-resolution, gamma-ray spectroscopy technique to analyze gaseous plutonium hexafluoride. For the first time, PuF6 gas samples with pressures varying from 0.15 to 31 torr, which were directly fed into a gas cell from a process flow loop, were measured. The isotopic results of these measurements agree very well with those of mass spectrometry measurements of solid PuF4. The precision of a 10-min measurement of a 10-torr reactor-grade PuF6 is 1.5% for 238Pu, 0.22% for 239Pu, 0.87% for 240Pu, and 17.5% for 241Pu

  8. Activation analysis and isotope dilution applied to the determination of rare earth elements in ytrium oxides

    A method for determining rare earth elements from matrix constituted by sample of ytrium oxide is shown. Ion exchange technique and electron with chelating agent have been chosen for chemical separations. The method consists of using isotope dilution followed by activation analysis in order to determine the amounts of the elements

  9. Thin layer activation analysis of α induced reactions for surface wear studies in some natural isotopes

    The thin layer activation technique is widely used to study surface wear and erosion by employing medium energy, light charged particle accelerators in the micrometer range. In the present work, TLA technique has been explored using gamma spectroscopy for a large number of reactions in several isotopes, which may be of interest for the reactor technology

  10. Neutron activation analysis of stable isotopic tracers for studies of mineral bioavailability

    With increased recognition of the importance of trace minerals in nutrition it is necessary to investigate factors affecting their absorption. Enriched stable isotopic tracers with determination by neutron activation analysis or mass spectroscopy have been used to investigate the absorption of minerals by term and pre-term babies and to compare their absorption from infant formulae, without any radiological risk. (UK)

  11. A 233U/236U/242Pu/244Pu spike for isotopic and isotope dilution analysis by mass spectrometry with internal calibration

    The Khlopin Radium Institute prepared on behalf of the IAEA a synthetic mixture of 233U, 236U, 242Pu and 244Pu isotopes. The isotopic composition and elemental concentration of uranium and plutonium were certified on the basis of analyses done by four laboratories of the IAEA Network, using mass spectrometry with internal standardization. The certified values for 233U/236U ratio and the 236U chemical concentration have a coefficient of variation of 0.05%. The latter is fixed by the uncertainty in the 235U/238U ratio of NBS500 used as internal standard. The coefficients of variation of the 244Pu/242Pu ratio and the 242Pu chemical concentration are respectively 0.10% and 0.16% and limited by the uncertainty in the 240Pu/239Pu ratio of NBS947. This four isotope mixture was used as an internal standard as well as a spike, to analyze 30 batches of LWR spent fuel solutions. The repeatability of the mass spectrometric measurements have a coefficient of variation of 0.025% for the uranium concentration, and of 0.039% for the plutonium concentration. The spiking and treatment errors had a coefficient of variation of 0.048%. (author). Refs, figs and tabs

  12. Study on bioavailability of dietary iron of women by using activable isotopic tracer and neutron activation analysis techniques

    The bioavailability of diet iron of 10 healthy young women in Beijing area is studied by using two enriched isotopes 54Fe and 58Fe, and neutron activation analysis techniques. The abundance of 54Fe and 58Fe is 61.4% and 23.4%, respectively. In additional, the atomic absorption spectrometry is employed to measure total iron in fecal samples. Dysprosium, rarely absorbed by human body, is used to monitor the residence time of tracer isotopes in order to collect the fecal samples completely. The results show that the bioavailability of dietary iron in young women is (14.9 +- 3.9)%

  13. Anthropogenic radionuclides in fish, shellfish, algae and sediments from the Sudanese Red Sea coastal environment

    The activity concentration of fallout radionuclides viz. 238Pu, 239+240Pu, 241Am, 137Cs and 90Sr has been measured in some species of multicellular marine algae, coral fishes and shellfish, and surface sediments collected from the fringing reef at different locations along the Sudanese coast of the Red Sea. The measurements were carried out using alpha-particle spectrometry, high-resolution gamma spectrometry and gas-flow proportional counter. In the sediments analyzed, the activity concentration averaged 2.65 ± 1.3 (238Pu), 47.96 ± 26.3 (239+240Pu), 19.1 ± 6.5 (241Am), 273 ± 157 (137Cs) and 140.8 ± 73.9 (90Sr) mBq/kg dry weight. Activity concentration ratios were 0.066 ± 0.041 (238Pu: 239+240Pu), 0.22 ± 0.04 (239+240Pu:137Cs), and 0.43 ± 0.1 (241Am:239+240Pu). These values are typical of those reported in the literature from the regions unaffected directly by nuclear accidents or nuclear reprocessing plant discharges and can thus be attributed to global fallout. Average activity concentrations (mBq/gk Dry weight) in marine algae from different locations were found to be 20.1 ± 14.1, 21.6 ± 13.3 and 8.5 ± 3.8 (239+240Pu), 6.2 ± 4.0, 11.7 ± 6.1 and 5.1 ± 3.5 (241Am) and 688 ± 242, 868 ± 713 and 116 ± 14.8 (137Cs) for brown, red and green algae, respectively. These results were found to be consistently decrease towards the south from Portsudan harbour and comparable to global fallout values. High levels of 137Cs were observed in brown algae (Cystoseria species) and red algae (Lauranthia species). This possibly suggests their suitability to be used as bioindicators since algae are known to be effective bioindicators for monitoring the anthropogenic radioactivity in the marine environment. Plutonium isotopes were measured in some species of coral fishes and shellfish samples from the fringing reefs area at Port Sudan. Activity concentrations of both 238Pu, 239+240Pu in fish are close to detection limits, while shellfish show values an order of

  14. Anthropogenic radionuclides in fish, shellfish, algae and sediments from the Sudanese Red Sea coastal environment

    The activity concentration of fallout radionuclides v.z.,238Pu ,239+240Pu, 241Am,137Cs and 90Sr has been measured in some species of multicellular marine algae, coral fishes and shellfish, and surface sediments collected from the fringing reef at different locations along the Sudanese coast of the Red Sea. The measurements were carried out using alpha-particle spectrometry, high-resolution gamma spectrometry and gas-flow proportional counter. In the sediments analyzed, the activity concentration averaged 2.65±1.3 (238Pu), 47.96 ± 26.3 (239+240Pu), 19.1± 6.5 (241Am), 273 ± 157 (137Cs) and 140.8±73.9 (90Sr) mBq/kg dry weight. Activity concentration ratios were 0.066±0.041 (238Pu: 239+240Pu), 0.22±0.04 (239+240Pu:137Cs), and 0.43±0.1 (241Am:239+240Pu). These values are typical of those reported in the literature from the regions unaffected directly by nuclear accidents or nuclear reprocessing plant discharges and can thus be attributed to global fallout. Average activity concentrations (mBq/gk Dry weight) in marine algae from different locations were found to be 20.1±14.1, 21.6±13.3 and 8.5±3.8 (239+240Pu), 6.2±4.0, 11.7±6.1 and 5.1±3.5 (241Am) and 688±242, 868±713 and 116±14.8 (137Cs) for brown, red and green algae, respectively. These results were found to be consistently decrease towards the south from Portsudan harbour and comparable to global fallout values. High levels of 137Cs were observed in brown algae (Cystoseria species) and red algae (Lauranthia species). This possibly suggests their suitability to be used as bioindicators since algae are known to be effective bioindicators for monitoring the anthropogenic radioactivity in the marine environment. Plutonium isotopes were measured in some species of coral fishes and shellfish samples from the fringing reefs area at Port Sudan. Activity concentrations of both 238Pu ,239+240Pu in fish are close to detection limits, while shellfish show values an order of magnitude higher relative to coral

  15. Isotope identification of Langkawi black sand using neutron activation analysis

    The Langkawi black sand has been analyzed using the method of neutron activation analysis (INAA). A total of 22 elements have been detected. Elements such as Mn, Cu, Cr, U and Th occur in high concentration. Prospect for future mineralization of these elements may be of economic interest. (author) 9 refs.; 1 tab

  16. ZPR-6 assembly 7 high {sup 240} PU core : a cylindrical assemby with mixed (PU, U)-oxide fuel and a central high {sup 240} PU zone.

    Lell, R. M.; Schaefer, R. W.; McKnight, R. D.; Tsiboulia, A.; Rozhikhin, Y.; Nuclear Engineering Division; Inst. of Physics and Power Engineering

    2007-10-01

    Over a period of 30 years more than a hundred Zero Power Reactor (ZPR) critical assemblies were constructed at Argonne National Laboratory. The ZPR facilities, ZPR-3, ZPR-6, ZPR-9 and ZPPR, were all fast critical assembly facilities. The ZPR critical assemblies were constructed to support fast reactor development, but data from some of these assemblies are also well suited to form the basis for criticality safety benchmarks. Of the three classes of ZPR assemblies, engineering mockups, engineering benchmarks and physics benchmarks, the last group tends to be most useful for criticality safety. Because physics benchmarks were designed to test fast reactor physics data and methods, they were as simple as possible in geometry and composition. The principal fissile species was {sup 235}U or {sup 239}Pu. Fuel enrichments ranged from 9% to 95%. Often there were only one or two main core diluent materials, such as aluminum, graphite, iron, sodium or stainless steel. The cores were reflected (and insulated from room return effects) by one or two layers of materials such as depleted uranium, lead or stainless steel. Despite their more complex nature, a small number of assemblies from the other two classes would make useful criticality safety benchmarks because they have features related to criticality safety issues, such as reflection by soil-like material. The term 'benchmark' in a ZPR program connotes a particularly simple loading aimed at gaining basic reactor physics insight, as opposed to studying a reactor design. In fact, the ZPR-6/7 Benchmark Assembly (Reference 1) had a very simple core unit cell assembled from plates of depleted uranium, sodium, iron oxide, U3O8, and plutonium. The ZPR-6/7 core cell-average composition is typical of the interior region of liquid-metal fast breeder reactors (LMFBRs) of the era. It was one part of the Demonstration Reactor Benchmark Program,a which provided integral experiments characterizing the important features of demonstration-size LMFBRs. As a benchmark, ZPR-6/7 was devoid of many 'real' reactor features, such as simulated control rods and multiple enrichment zones, in its reference form. Those kinds of features were investigated experimentally in variants of the reference ZPR-6/7 or in other critical assemblies in the Demonstration Reactor Benchmark Program.

  17. Reconstruction of historical lead contamination and sources in Lake Hailing, Eastern China: a Pb isotope study.

    Zhang, Rui; Guan, Minglei; Shu, Yujie; Shen, Liya; Chen, Xixi; Zhang, Fan; Li, Tiegang; Jiang, Tingchen

    2016-05-01

    The history records of lead and its stable isotopic ratios were determined in a sediment core to receive anthropogenic impacts on the Lake Hailing in eastern China. The sediment core was dated based on (210)Pb, (137)Cs, and (239+240)Pu. The historical changes of Pb/Al and Pb isotope ratios showed increasing trend upward throughout the core, suggesting changes in energy usage and correlating closely with the experience of a rapid economic and industrial development of the catchment, Linyi City, in eastern China. Based on the mixing end member model of Pb isotope ratios, coal combustion emission dominated anthropogenic Pb sources in the half part of the century contributing 13 to 43 % of total Pb in sediment. Moreover, contributions of chemical and organic fertilizer were 1-13 and 5-14 %, respectively. In contrast, the contribution of leaded gasoline was low than 8 %. The results indicated that historical records of Pb contamination predominantly sourced from coal combustion and chemical and organic fertilizer in the catchment. In addition, an increase of coal combustion source and fertilizers was found throughout the sediment core, whereas the contribution of leaded gasoline had declined after 2000s, which is attributed to the phaseout of leaded gasoline in China. PMID:26832874

  18. Distribution of transuranic isotopes in the water of the North Sea and adjacent regions

    During the years 1978 to 1980 large scale investigations were carried out for the determination of transuranics in the Western Baltic Sea, in the Kattegat and Skagerrak, and in the whole of the North Sea including a strip to the West and East of the Orkney and Shetland Islands, as well as in a region between North Cape and Spitzbergen. The measurements in the North Sea region were carried out in order to gain better knowledge about the further spreading and behaviour of transuranic isotopes which are introduced into the sea from nuclear fuel reprocessing plants. As far as the other areas are concerned, measurements are intended to provide basic data to supplement the only very meagre data material available. The isotopes of 238Pu and 239+240Pu were determined from 60 l unfiltered seawater according to the method of Murray and Statham. Nevertheless, for analysis of 241Am, 200 l of seawater were required owing to the lower concentrations. For that reason, this isotope could be determined in only a limited number of samples taken from particularly interesting regions. The data of 1978 were made known in an earlier report; however, they are now interpreted together with the present results

  19. Plutonium dosage using isotopic dilution. Application to the study of irradiated fuels

    The uranium/plutonium ratio can be determined in a fuel after irradiation by isotopic dilution using a solution containing uranium 233 and plutonium enriched in the 240 or 242 isotopes. A description is given of the measurement method, the calibration, the solution preparation techniques and the mass spectrometric analysis. To use this method it is necessary, after mixing, for the isotopes to be distributed in the same way in the system both for the sample items and those of the tracer. This condition leads to difficulties which become apparent, particularly during calibration. The use of an electric computer, has made it possible to reduce the time required for analysis and to simplify the checking of results. The U/Pu ratio can be determined to 3 or 4 per cent if a 240Pu-rich tracer is used, and to better than 2 per cent using 242Pu. 235U consumption is measured. by a particular technique involving a uranium hexafluoride analysis. The depletion is measured to ± 5 x 10-4. (authors)

  20. Study on bioavailability of zinc for children's diet by using activable isotopic tracer 70Zn and neutron activation analysis techniques

    Bioavailability of zinc for three groups (low amount of diet zinc, balance amount of diet zinc and high amount of diet zinc) of children's diet is studied by using activable isotopic tracer 70Zn and neutron activation analysis techniques. The results indicate that the fractional absorption of zinc from balance diet zinc group is the highest, up to 33.9%. A procedure of pre-irradiation concentration zinc for fecal samples using anion exchanger is developed, and the enriched 70Zn with isotopic abundance of 18.3% is used for tracer. The mass ratios between 70Zn and 68Zn or 64Zn and their contents between natural zinc and enriched zinc are used to calculate the bioavailability of zinc. Instrumental neutron activation analysis of 64Zn of each original fecal samples and pre-irradiation concentrated zinc samples are used to normalize the chemical yield in order to reduce the uncertainty during the chemical separation procedure

  1. Isotopic techniques for measuring the biological activity in plant rhizosphere

    The use of 14C made it possible to separate root respired CO2 and microbial CO2 resulting from exudates utilisation by the rhizosphere microflora. Measurements were done after wheat plants grown under axenic and non axenic conditions were placed during short period of time in an atmosphere contaning 14CO2. Under axenic conditions evolution of 14CO2 follows a bell shaped curve due to the brief appearance of labelled compounds translocated from the aerial part of the plants to the roots. In the presence of microorganisms, the maximum of activity due to root respiration is identical but immediately followed by a second peak of 14CO2 evolution that was attributed to the decomposition of labelled exudates by the microflora. The same observations resulted from the labelling of a grassland vegetation sampled with its soil and placed in the laboratory. Preliminary results obtained using this method of short term labelling of plants are presented here

  2. Concentrations and activity ratios of uranium isotopes in groundwater from Donana National Park, South of Spain

    The levels and distribution of natural radionuclides in groundwaters from the unconfined Almonte-Marismas aquifer, upon which Donana National Park is located, have been analysed. Most sampled points were multiple piezometers trying to study the vertical distribution of the hydrogeochemical characteristics in the aquifer. Temperature, pH, electrical conductivity, dissolved oxygen and redox potential were determined in the field. A large number of parameters, physico-chemical properties, major and minor ions, trace elements and natural radionuclides (U-isotopes, Th-isotopes, Ra-isotopes and 210Po), were also analysed. In the southern zone, where aeolian sands crop out, water composition is of the sodium chloride type, and the lower U-isotopes concentrations have been obtained. As water circulates through the aquifer, bicarbonate and calcium concentrations increase slightly, and higher radionuclides concentrations were measured. Finally, we have demonstrated that 234U/238U activity ratios can be used as markers of the type of groundwater and bedrock, as it has been the case for old waters with marine origin confined by a marsh in the south-east part of aquifer

  3. Radiochemical neutron activation analysis of zinc for stable isotope tracer studies in human nutrition

    Stable isotopes are beginning to be used to study trace element nutrition in humans. As they do not expose subjects to radiation, they will be very useful for population groups that can not be studied with radioactive tracers (pregnant women and persons under the age of 18). The zinc stable isotope used in experiments was 70Zn whose abundance was increased from 0.62% to 66%. Blood, urine and feces samples were collected at various times after the administration of the tracer and the ratios of Zn-70/Zn-64 and Zn-70/Zn-68 were determined in the collected samples. Neutron Activation Analysis (NAA) was used to determine the Zn isotopes. As biological samples contain large quantites of Na, Cl, Br, K it was necessary to separate these in order to detect Zn isotopes. Pre and post-irradiation separations were done. Chelex-100 was used for former, Mn was precipitated as MnO2 and Cu was separated by dithizone extraction. The yields for pre and post-irradiation separations for 90 samples were 86+-16% and 70+-13% respectively. (author)

  4. Characterization of Tank 48H Samples for Alpha Activity and Actinide Isotopics

    This document reports the total alpha activity and actinide isotopic results for samples taken from Tank 48H prior to the addition of sodium tetraphenylborate and MST in Batch number-sign 1 of the ITP process. This information used to determine the quantity of MST for Batch number-sign 1 of the ITP process and the total actinide content in the tank for dose calculations

  5. Programming and detection of activity in an online isotope separation collector

    A device for programming irradiation, counting and printing times, to be used connected with on-line isotopic separation studies is described in this paper. On the other hand a fast mechanical transporting aluminum ribbon (0. 4 m/s) has been used to transfer the collected activity to the low background counting place. The working parameters can be suited to short half-lives (down to a few seconds) as well as for neutron induced uranium fission yields. (author)

  6. Cellular Metabolic Activity and the Oxygen and Hydrogen Stable Isotope Composition of Intracellular Water and Metabolites

    Kreuzer-Martin, H. W.; Hegg, E. L.

    2008-12-01

    Intracellular water is an important pool of oxygen and hydrogen atoms for biosynthesis. Intracellular water is usually assumed to be isotopically identical to extracellular water, but an unexpected experimental result caused us to question this assumption. Heme O isolated from Escherichia coli cells grown in 95% H218O contained only a fraction of the theoretical value of labeled oxygen at a position where the O atom was known to be derived from water. In fact, fewer than half of the oxygen atoms were labeled. In an effort to explain this surprising result, we developed a method to determine the isotope ratios of intracellular water in cultured cells. The results of our experiments showed that during active growth, up to 70% of the oxygen atoms and 50% of the hydrogen atoms in the intracellular water of E. coli are generated during metabolism and can be isotopically distinct from extracellular water. The fraction of isotopically distinct atoms was substantially less in stationary phase and chilled cells, consistent with our hypothesis that less metabolically-generated water would be present in cells with lower metabolic activity. Our results were consistent with and explained the result of the heme O labeling experiment. Only about 40% of the O atoms on the heme O molecule were labeled because, presumably, only about 40% of the water inside the cells was 18O water that had diffused in from the culture medium. The rest of the intracellular water contained 16O atoms derived from either nutrients or atmospheric oxygen. To test whether we could also detect metabolically-derived hydrogen atoms in cellular constituents, we isolated fatty acids from log-phase and stationary phase E. coli and determined the H isotope ratios of individual fatty acids. The results of these experiments showed that environmental water contributed more H atoms to fatty acids isolated in stationary phase than to the same fatty acids isolated from log-phase cells. Stable isotope analyses of

  7. Determination of activable isotopic tracers of zinc by neutron activation analysis for study of bioavailability of zinc

    A procedure of pre-irradiation concentration of zinc in fecal samples using anion exchanger was developed for the study of the bioavailability of zinc by neutron activation analysis. The mass ratios between 70Zn and 68Zn, or 64Zn and their contents between natural zinc and enriched zinc are used to calculate the bioavailability of zinc when the abundance of the isotope 70Zn is not high enough. (author) 9 refs.; 1 fig.; 2 tabs

  8. Comparison of uranium and radium isotopes activities in some wells and thermal springs samples in Morroco

    Activities and activity ratios of uranium and radium isotopes (234U, 238U, 226Ra, 228Ra, 234U/238U, 226Ra/238U, 228Ra/226Ra) have been determined, for the first time in Morocco, for 15 well water samples and 12 spring water samples. The obtained results show that, unlike well waters, the thermal spring waters present relatively low 238U activities and elevated 226Ra activities and 234U/238U activity ratios. Uranium and radium activities are similar to those published for other non polluting regions of the world, they are inferior to the Maximum Contaminant Levels and don't present any risk for public health in Morocco. (author)

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

    The aim of this work was to calculate the values of the 234U/238U activity ratio in natural environment (water, sediments, Baltic organisms and marine birds from various regions of the southern Baltic Sea; river waters (the Vistula and the Oder River); plants and soils collected near phosphogypsum waste heap in Wislinka (Northern Poland) and deer-like animals from Northern Poland. On the basis of the studies it was found that the most important processes of uranium geochemical migration in the southern Baltic Sea ecosystem are the sedimentation of suspended material and the vertical diffusion from the sediments into the bottom water. Considerable values of the 234U/238U are characterized for the Vistula and Oder Rivers and its tributaries. The values of the 234U/238U activity ratio in different tissues and organs of the Baltic organisms, sea birds and wild deer are varied. Such a large variation value of obtained activity ratios indicates different behavior of uranium isotopes in the tissues and organisms of sea birds and wild animals. This value shows that uranium isotopes can be disposed at a slower or faster rate. The values of the 234U/238U activity ratio in the analyzed plants, soils and mosses collected in the vicinity of phosphogypsum dumps in Wislinka are close to one and indicate the phosphogypsum origin of the analyzed nuclides. Uranium isotopes 234U and 238U are not present in radioactive equilibrium in the aquatic environment, which indicates that their activities are not equal. The inverse relationship is observed in the terrestrial environment, where the value of the of the 234U/238U activity ratio really oscillates around unity. (author)

  10. Bulk - Samples gamma-rays activation analysis (PGNAA) with Isotopic Neutron Sources

    An overview is given on research towards the Prompt Gamma-ray Neutron Activation Analysis (PGNAA) of bulk-samples. Some aspects in bulk-sample PGNAA are discussed, where irradiation by isotopic neutron sources is used mostly for in-situ or on-line analysis. The research was carried out in a comparative and/or qualitative way or by using a prior knowledge about the sample material. Sometimes we need to use the assumption that the mass fractions of all determined elements add up to 1. The sensitivity curves are also used for some elements in such complex samples, just to estimate the exact percentage concentration values. The uses of 252Cf, 241Arn/Be and 239Pu/Be isotopic neutron sources for elemental investigation of: hematite, ilmenite, coal, petroleum, edible oils, phosphates and pollutant lake water samples have been mentioned.