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Sample records for 241am 243am 245cm

  1. Fission Cross-section Measurements of (233)U, (245)Cm and (241,243)Am at CERN n_TOF Facility

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

    2011-01-01

    Neutron-induced fission cross-sections of minor actinides have been measured using the n_TOF white neutron source at CERN, Geneva, as part of a large experimental program aiming at collecting new data relevant for nuclear astrophysics and for the design of advanced reactor systems. The measurements at n_TOF take advantage of the innovative features of the n_TOF facility, namely the wide energy range, high instantaneous neutron flux and good energy resolution. Final results on the fission cross-section of 233U, 245Cm and 243Am from thermal to 20 MeV are here reported, together with preliminary results for 241Am. The measurement have been performed with a dedicated Fast Ionization Chamber (FIC), a fission fragment detector with a very high efficiency, relative to the very well known cross-section of 235U, measured simultaneously with the same detector.

  2. Competence of alpha spectrometry analysis algorithms used to resolve the 241Am and 243Am alpha peak overlap

    Five alpha spectrometry analysis algorithms were evaluated for their ability to resolve the 241Am and 243Am peak overlap present under typical low-level counting conditions. The major factors affecting the performance of the algorithms were identified using design-of-experiment combined with statistical analysis of the results. The study showed that the accuracy of the 241Am/243Am ratios calculated by the algorithms depends greatly on the degree of peak deformation and tailing. Despite the improved data quality obtained using an algorithm that may include peak addition and tail estimation, the accurate determination of 241Am by alpha spectrometry relies primarily on reduction of peak overlap rather than on algorithm selection

  3. Neutron capture cross section measurements of $^{238}$U, $^{241}$Am and $^{243}$Am at n_TOF

    Koehler, P E; Plag, R

    The increase of the world energy demand and the need of low carbon energy sources have triggered the renaissance and/or enhancement of nuclear energy in many countries. Fundamental nuclear physics can contribute in a practical way to the sustainability and safety of the nuclear energy production and the management of the nuclear waste. There exists a series of recent studies which address the most relevant isotopes, decay data, nuclear reaction channels and energy ranges which have to be investigated in more detail for improving the design of different advanced nuclear systems [1] and nuclear fuel cycles [2]. In this proposal, we aim at the measurement of the neutron capture cross sections of $^{238}$U, $^{241}$Am and $^{243}$Am. All three isotopes are listed in the NEA High Priority Request List [37], are recommended for measurements [1] and play an important role in the nuclear energy production and fuel cycle scenarios. The measurements will provide as well valuable nuclear structure data necessary for the...

  4. The use of isotopic correlation technique for determination of sup(241)Am and sup(243)Am concentration in nuclear irradiated fuels

    In the last years the isotopic correlation technique is emerging as a powerful tool for the determination of concentration and isotopic composition of heavy nuclides in the nuclear fuel cycle. Accordingly, this technique has gained significant importance for the safeguard of the nuclear materials as well as for the accounting and build up of actinides elements in the irradiated nuclear fuels. In this work 42 isotopic correlations between the nuclides sup(241)Am and sup(243)Am and post irradiation isotopic data of 7 samples from fuel element BE-124 and 1 sample from fuel element BE-120 from the Obrigheim pressurized water nuclear power reactor, Federal Republic of Germany, were proposed. These isotopic correlations allowed to estimate the isotopic concentrations of sup(241)Am and sup(243)Am with an average deviation, relative to the experimental data obtained from isotopic dilution mass spectrometry technique, of 10%. These results are more precise than those found using the computer code ORIGEN 2 demonstrating the great potential of this technique for the determination of isotopic concentration and build up of those nuclides in irradiated nuclear fuels. The analytical and other experimental aspects of the post irradiation isotopic analysis of nuclear fuels are also discussed. (author)

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

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

    2002-01-01

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

  6. Measurements of energy dependence of average number of prompt neutrons from neutron-induced fission of 235U, 241Am and 243Am from 0.5 to 12 MeV

    The energy dependence measurements results of average number of prompt neutrons from neutron-induced fission of 235U, 241Am, 243Am and total gamma-rays energy for 235U and 243Am from 0.5 to 12 MeV are presented. The measurements were carried out with neutron beam from uranium target of electron linac of All-Union Scientific Research Institute of Experimental Physics using time-of-flight technique on 28.5 m flight-path. The neutrons and gamma-rays from fission were detected by a big liquid scintillator detector (BLSD) loaded with gadolinium, events of fission - by parallel plate avalanche detector for fission fragments. Measurement of energy dependence of anti νp, Eγtot and determination of BLSD efficiency (relative to anti νp and Eγtot for 252Cf) were carried out simultaneously. Least squares fitting results give anti νp=3.05+0.14degEn for 241Am and anti νp=3.20+.15degEn for 243Am. (orig.)

  7. Characterization of strong 241Am sources

    Gamma ray spectra of strong 241Am sources may reveal information about the source composition as there may be other radioactive nuclides such as progeny and radioactive impurities present. In this work the possibility to use gamma spectrometry to identify inherent signatures in 241Am sources in order to differentiate sources from each other, is investigated. The studied signatures are age, i.e. time passed since last chemical separation, and presence of impurities. The spectra of some sources show a number of Doppler broadened peaks in the spectrum which indicate the presence of nuclear reactions on light elements within the sources. The results show that the investigated sources can be differentiated between by age and/or presence of impurities. These spectral features would be useful information in a national nuclear forensics library (NNFL) in cases when the visual information on the source, e.g. the source number, is unavailable. - Highlights: • Age and impurities can be used as a signature for 241Am sources. • Nuclear reactions take place in sources with low Z impurities. • Some sources contain 243Am as an impurity

  8. Beneficial uses of 241Am

    This report assesses the uses of 241Am and the associated costs and supply. The study shows that 241Am-fueled radioisotope thermoelectric generators in the range of 1 to 5 W electrical provide the most promising use of kilogram amounts of this isotope. For medical uses, where purity is essential, irradiation of 241Am can produce 97% pure 238Pu at $21,000/g. Using a pyro-metallurgical process, 241Am could be recovered from molten salt extraction (MSE) residues at an estimated incremental cost of $83/g adjusted to reflect the disposal costs of waste products. This cost of recovery is less than the $300/g cost for disposal of the 241Am contained in the MSE residues

  9. The influence of impurities for cross section measurement of {sup 241,243}Am(n,f) reactions

    Kai, Tetsuya; Kobayashi, Katsuhei; Yamamoto, Shuji; Fujita, Yoshiaki; Kimura, Itsuro; Miyoshi, Mitsuharu; Yamamoto, Hideki [Kyoto Univ. (Japan); Shinohara, Nobuo

    1997-03-01

    The influence of the impurities on the fission cross section measurements for {sup 241}Am and {sup 243}Am has been investigated with the practical results. Following cases have been considered as the influence of impurities; (a) experiments with the {sup 241}Am sample that contains impurities originally, and (b) experiments with the {sup 243}Am sample that contains impurities produced by {alpha}, {beta} decays after the chemical purification. The present study has demonstrated the usefulness of pure samples by the comparison of the experiments using the sample on the market with those using the pure sample processed by the authors. Particularly on the case (b), the correction of the impurity through the periodical measurements was experimentally performed (about 18% around 0.3 eV in 4 weeks after the chemical purification). (author)

  10. Determination of 241Am in reindeer bone

    The purpose of this work was to develop a procedure to separate americium from other alpha active nuclides present in reindeer bone samples, especially 228Th and its daughter nuclides. The 241Am-spectrum of a reindeer bone sample analyzed using the proposed method is given. The α-spectrum was measured one week after electrodeposition. The absence of the alpha peak of 224Ra, the daughter nuclide of 228Th, indicates that no 228Th was electrodeposited onto the platinum disc. Four reindeer bone samples were analyzed for 241Am using the method developed. The 241Am/239240Pu activity ratio in reindeer bone was 0.9 :- 0.4. These results indicate that compared to plutonium, americium is accumulated in reindeer bone more heavily than in liver. All 241Am values presented are concentrations at the time of radioassay, and no correction has been made for the ingrowth of 241Am formed by the decay of 241Pu during stockpilling. However, all 241Am determinations were made 1 to 3 yrs after sample collection, and thus the corrections due to the ingrowth can be considered slight. About 60% of plutonium body burden is located in liver and 20% in skeleton. The activity ratio 241Am/239240Pu in these animals was about 0.2 and 1.0 in liver and skeleton, respectively. This indicates that about 60% of the 241Am body burden is located in skeleton and about 30% in liver. It can be roughly estimated that the whole-body activity of 241Am is thus about 40% of the 239240Pu body burden

  11. Biosorption of 241Am by R. arrihizus

    The Biosorption of radionuclide 241Am on R.arrihizus from aqueous solution and the effects of the experimental conditions on the biosorption are investigated by the batch technique. The experimental results show that the R.arrihizus is a very efficient sorbent. The biosorption reaches equilibration in 1 h, the optimum pH range is 1-3. No significant temperature effect on 241Am biosorption is observed in the range of 10-45 degree C. No significant differences of biosorption in the presence and absence of Au3+ or Ag+ are observed. The relationship between concentrations of 241Am in aqueous solutions and adsorption capacities of 241Am can be described by the Freundlich adsorption equation

  12. Biosorption of 241Am by microorganism

    The biosorption of 241Am on A. niger, R. arrihizus and Candida albicans from aqueous solution, and the effects of the experimental conditions on the biosorption are investigated by the batch technique. The experimental results show that all the microorganism above are very efficient as the sorbent. The biosorption equilibrium time is 2 h and the optimum pH ranges 1-3. No significant differences on 241Am biosorption are observed at the temperature of 15-45 degree C, or in the presence and absence of Au3+ or Ag+. The relationship between concentrations of 241Am in aqueous solutions and adsorption capacities of 241Am can be described by the Freundlich adsorption equation on A. niger and R. arrihizus, while as it can be done by the Langmuir adsorption equation on Candida albicans

  13. Biosorption of 241Am by Candida sp

    The biosorption of radionuclide 241Am from solutions by Candida sp., and the influences of experimental conditions on the adsorption were studied. The results showed that the adsorption equilibrium was achieved within 4h and the optimum pH=2. No significant differences on 241Am biosorption were observed at 10-45 degree C, or challenged with Au3+ or Ag+, even 1500 times or 4500 times over 241Am, respectively. The adsorption rate could reach 97.8% by dry Candida sp. of 0.82 g/L in 241Am solutions (pH=2) of 5.6-111 MBq/L (44.04-873.0 μg/L) (C0), with maximum adsorption capacity (W) of 63.5 MBq/g (501.8 μg/g), implying that the removal of 241Am by Candida sp. from solutions was feasible. The relationship between activities (C0) and adsorption capacities (W) of 241Am indicated that the biosorption process could be described by Langmuir adsorption isotherm

  14. Plant uptake and transport of 241Am

    We conducted several experiments with 241Am to obtain a more complete understanding of how this transuranium element is absorbed and transported in plants. In a plant species (Tamarix pentandra Pall.) that has salt glands in the leaves excreting NaCl and other ions, 241Am was not pumped through these glands. Cyanide, which forms complexes with any metals, when applied to a calcareous soil, greatly increased the transport of 241Am into stems and leaves of bush bean plants. Radioactive cyanide (14C) was also transported to leaves and stems. When radish was grown in both calcareous and noncalcareous soils, 241Am appeared to be fixed on the peel so firmly that it was resistant to removal by HNO3 washing. The chelating agent DTPA induced increased transport of 241Am to leaves and into the fleshy roots of the radish. Data for Golden Cross hybrid corn grown in solution culture showed at least seven times as much 241Am transport to the xylem exudatields are corrected by recovery of added tracers

  15. Excretion analysis of a case of old internal contamination with 241Am

    Two radiochemical methods were used in parallel to determine 241Am in the urine and feces of a person who had been internally contaminated with that radionuclide 25 years before. Both methods used feces and urine mineralizations. The first method comprised coprecipitation of Am together with alkaline earth metals by using bismuth phosphate, single separation on a catex, double separation on an anex, and extraction of Am into TTA in benzene. The other method consists of double coprecipitation of Am, viz., with calcium oxalate and with Fe(OH)3, followed by double separation on an anex and a single separation on a catex. In both methods, 243Am served as the recovery indicator and in the preparation of electrodeposition samples. The samples were measured by alpha spectrometry using PIPS detectors

  16. Preparation of tracer 239Np from 243Am

    The aim of this work is the preparation of tracer 239Np from 243Am by extraction chromatography as a separation method that can be used as a tracer to determine the radiochemical yield of 237Np in the analysis of environmental samples. (authors)

  17. Gamma-ray spectra of 241Am

    The γ-spectrum of 241Am was reinvestigated by using intense sources (100 and 25 mCi) for the energy range of Eγ>60 keV, and purified solution source of about 10 μCi for the low energy and to make sure that the γ-lines present in the spectrum come from the α-decay of 241Am. The study was divided into three parts. The γ-spectrometers consists of 40 and 10% relative efficiency Hp Ge detectors and 8192 channel ADC for normal spectra, and Si-Li for low energy. Outs of 169 γ-lines that are presented in the spectrum 47 are new. The major part of the new gamma lines was observed in the energy range of Eγ≥200 keV. (author)

  18. Measurement of contamination by 241Am

    In relation to the fact that four employees at the Danish Isotope Center who had regularly cleaned the smoke detectors used for control measurements were found to be contaminated with 241Am, the aim was to investigate the suitability of the Phoswich detector system for measurement of contamination of humans by 241Am. It was also wished to compare this measuring method with other selected ones. The measurement results are presented in detail. It was found that measurements taken on the cranium with the Phoswich detectors were more suitable for measurement of contamination by 241Am than the use of a Ge detector on the liver, - because of the first-named method's greater degree of measuring efficiency, (0.013 cps/Bq compared with 0.0001 cps/Bq in the case of Ge detector measurement) and lower minimum detectable activity in relation to that activity that was measured on A1 (one of the employees). It was found that Phoswich-detector measurement and measuring of urine samples supplemented each other in a satisfactory way. The Phoswich detector enables a quick measurement of the degree of seriousness of the contamination of a person and a relatively accurate determination of the calculated intake of contamination which has a size of at least twice the annual limit of intake size. Measurements of urine samples enable smaller amounts of contamination to be revealed, but this takes ca. 32 weeks and is less accurate than Phoswich measurement especially if a long time has elapsed after the intake. (AB) (34 refs.)

  19. Fission dynamics study in 243Am and 254Fm

    Banerjee, K.; Ghosh, T. K.; Roy, P.; Bhattacharya, S.; Chaudhuri, A.; Bhattacharya, C.; Pandey, R.; Kundu, S.; Mukherjee, G.; Rana, T. K.; Meena, J. K.; Mohanto, G.; Dubey, R.; Saneesh, N.; Sugathan, P.; Guin, R.; Das, S.; Bhattacharya, P.

    2016-06-01

    Fission fragment mass distributions in the reactions 11B + 232Th and 11B + 243Am were measured in an energy range around the barrier. No sudden change in the width of the mass distribution as a function of center-of-mass energy was observed at near-barrier energies, indicating no quasifission transition in the near-barrier energies. Interestingly, the previous measurements of fission fragment angular anisotropies for the same systems showed significant departure from the statistical saddle-point model predictions at near-barrier energies, indicating the presence of nonequilibrium fission processes.

  20. Neutron transmission and capture of 241Am

    A set of neutron transmission and capture experiments based on the Time Of Flight (TOF) technique, were performed in order to determine the 241Am capture cross section in the energy range from 0.01 eV to 1 keV. The GELINA facility of the Institute for Reference Materials and Measurements (IRMM) served as the neutron source. A pair of C6D6 liquid scintillators was used to register the prompt gamma rays emerging from the americium sample, while a Li-glass detector was used in the transmission setup. Results from the capture and transmission data acquired are consistent with each other, but appear to be inconsistent with the evaluated data files. Resonance parameters have been derived for the data up to the energy of 100 eV. (authors)

  1. Accumulation and retention of 241Am in marine plankton

    Two samples of sea water spiked with 241Am were prepared, one containing a rich suspension of phytoplankton cells and the other not. Adult Artemia brine shrimp were placed in each sample and the accumulation, uptake and concentration factors were obtained. Results from the Artemia uptake show that 241Am is far more effectively accumulated from the water pathway than from the combined food and water pathway. The experiments indicate that 241Am is relatively non-assimilatable when digested and thus most, if not all, of the isotope is rapidly voided in fecal pellets

  2. Photon interaction studies using 241Am -rays

    N Ramachandran; K Karunakaran Nair; K K Abdullah; K M Varier

    2006-09-01

    We have carried out some photon interaction measurements using 59.54 keV -rays from a 241Am source. These include attenuation studies as well as photoelectric absorption studies in various samples. The attenuation studies have been made using leaf and wood samples, samples like sand, sugar etc., which contain particles of varying sizes as well as pellets and aqueous solutions of rare earth compounds. In the case of the leaf and wood samples, we have used the -ray attenuation technique for the determination of the water content in fresh and dried samples. The variation of the attenuation coefficient with particle size has been investigated for sand and sugar samples. The attenuation studies as well as the photoelectric studies in the case of rare earth elements have been carried out on samples containing such elements whose K-absorption edge energies lie below and close to the -energy used. Suitable compounds of the rare earth elements have been chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. A well-shielded scattering geometry was used for the photoelectric measurements. The mixture rule was invoked to extract the values of the mass attenuation coefficients for the elements from those of the corresponding compounds. The results are consistent with theoretical values derived from the XCOM package.

  3. Characterisation of a protection level 241Am calibration source

    A 241Am radioactive source and transport mechanism was installed at the National Physical Laboratory in December 1991 to be used for protection level calibration work. This report details the various measurements involved in the commissioning process. (Author)

  4. Motivation for New Measurements on 241, 242, 243Am Isotopes

    The initial objective of this work was an updated review on the Am isotopes data since the next official release (3.1) of the JEFF3 evaluated data file is foreseen around June 2005. Alternatively, this work searches for the possible reasons of the observed discrepancies between differential and integral measurement results. In particular, strong differences are encountered on σγth values and epithermal branching ratio values for the 241Am. Although the JEF2.2 validation is used as guide in parallel with a systematic study of all differential and integral results available, the need for new measurements clearly shows up. This paper finally draws up a list of desired and feasible new differential and integral measurements on the Am isotopes

  5. 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)

  6. Biosorption of 241Am by immobilized Saccharomyces cerevisiae

    Americium-241 is one of the most serious radioactive contaminating nuclides due to its high toxicity and long half-life. The encouraging biosorption of 241Am from aqueous solutions by free Saccharomyces cerevisiae (S. cerevisiae) has been observed in our previous experiments. 241Am biosorption by immobilized S. cerevisiae and the effect of the various experimental conditions on the adsorption were investigated. The results indicated that the 241Am biosorption by immobilized S. cerevisiae is still very efficient, and immobilized S. cerevisiae can be used repeatedly or continuously. The biosorption equilibrium was achieved within 2 hours, and more than 92% of 241Am was removed by immobilized S. cerevisiae in the pH 1-4 range. No significant differences in 241Am biosorption were observed at 15-45 deg C. The immobilized S. cerevisiae, even after used repeatedly for 6 times, still could adsorb more than 90% of 241Am in solutions of 1.08 MBq/l (8.5 μg/l). At this moment, the total adsorption capacity for 241Am was more than 63.3 KBq/g globe (0.5 μg/g), but has not reached saturation yet. The 241Am left in solutions with initial concentration of 1.08 MBq/l (8.5 μg/l) was noted as low as ∼10 Bq/l (∼8.0 x 10-5 μg/l) after adsorption by the immobilized S. cerevisiae for 3 times. (author)

  7. Comparison of two leg phantoms containing (241)Am in bone.

    Kramer, Gary H; Hauck, Barry; Capello, Kevin; Rühm, Werner; El-Faramawy, Nabil; Broggio, David; Franck, Didier; Lopez, Maria Antonia; Navarro, Teresa; Navarro, Juan Francisco; Perez, Begoña; Tolmachev, Sergei

    2011-09-01

    Three facilities (CIEMAT, HMGU and HML) have used their in vivo counters to compare two leg phantoms. One was commercially produced with (241)Am activity artificially added to the bone inserts. The other, the United States Transuranium and Uranium Registries' (USTUR) leg phantom, was manufactured from (241)Am-contaminated bones resulting from an intake. The comparison of the two types of leg phantoms showed that the two phantoms are not similar in their activity distributions. An error in a bone activity estimate could be quite large if the commercial leg phantom is used to estimate what is contained in the USTUR leg phantom and, consequently, a real person. As the latter phantom was created as a result of a real contamination, it is deemed to be the more representative of what would actually happen if a person were internally contaminated with (241)Am. PMID:21799341

  8. Method comparison for 241Am emergency urine bioassay.

    Li, Chunsheng; Sadi, Baki; Benkhedda, Karima; St-Amant, Nadereh; Moodie, Gerry; Ko, Raymond; Dinardo, Anthony; Kramer, Gary

    2010-10-01

    241Am is one of the high-risk radionuclides that might be used in a terrorist attack. 241Am in urine bioassay can identify the contaminated individuals who need immediate medical intervention and decontamination. This paper compares three methods for the measurement of 241Am in urine, namely liquid scintillation counting (LSC), inductively coupled plasma mass spectrometry (ICP-MS) and gamma spectrometry (GS), at two levels, 20 and 2 Bq l(-1). All three methods satisfied the ANSI N13.30 radio-bioassay criteria for accuracy and repeatability. ICP-MS offered the best sensitivity and fastest sample turnaround; however, the ICP-MS system used in this work may not be available in many bioassay laboratories. LSC and GS are more commonly available instruments. GS requires minimal or no sample preparation, which makes it a good candidate method. Moreover, the sample throughput can be significantly improved if the GS and LSC methods are automated. PMID:20573683

  9. Solubilization of 241AmO2 in siderophore solutions

    The solubilization of 241AmO2 in tissue culture medium was measured. Variables included serum concentration, chelon type, and time. Serum was found to affect the soluble (0.1 μm filterable) fraction more than any other variable

  10. The Cases of Internal Contamination with 241Am

    Full text: Up to present time, 14 people with intake of 241Am were measured by direct methods and also their excreta were analysed. Different approaches for the estimation of whole body content of 241Am were used. For the direct measurement, method of counting of 241Am in the skull is the most sensitive one. Introduction of this method for the routine in vivo measurements of the workers means that more cases with 241Am internal contamination were identified than before, when only simple whole body counting has been used. The most sensitive method is excretion analysis, which is, of course, quite time consuming. The interpretation of it is much more dependent on the assumed time of intake. Evaluation of the intake from the measurement in the skeleton is less dependent on the time of intake. It is not sensitive enough for monitoring of occupational exposure. This method is especially suitable for follow up of cases with old intakes. When higher inhalation intakes occur (both continuous and single accidental), combination of both approaches direct measurements in vivo and excretion analysis helps to estimate time of intake and enable to estimate committed effective dose in a realistic way. (author)

  11. Tagging fast neutrons from an (241)Am/(9)Be source.

    Scherzinger, J; Annand, J R M; Davatz, G; Fissum, K G; Gendotti, U; Hall-Wilton, R; Håkansson, E; Jebali, R; Kanaki, K; Lundin, M; Nilsson, B; Rosborge, A; Svensson, H

    2015-04-01

    Shielding, coincidence, and time-of-flight measurement techniques are employed to tag fast neutrons emitted from an (241)Am/(9)Be source resulting in a continuous polychromatic energy-tagged beam of neutrons with energies up to 7MeV. The measured energy structure of the beam agrees qualitatively with both previous measurements and theoretical calculations. PMID:25644080

  12. Methods of assessment of whole body 241Am content

    This paper discuss an influence of different skull phantoms on efficiency of the measurement. Description of some methods of an assessment of the 241Am content in the human skeleton from measurements performed over long bones of the human body is also offered. (authors)

  13. Incorporation of 241Am: effectiveness of late DTPA chelation therapy

    In four persons who had incorporated 241Am probably by inhalation, a DTPA chelation therapy was initiated several months after incorporation. Excretion measurements and in vivo measurements were performed in order to quantify the enhancement of 241Am excretion and the activity distribution in the body. DTPA was administered 4-11 times as an infusion of 1 g DTPA. Daily excretion rates were raised essentially, up to factors of 65-140 (urine) and 30-50 (faeces) after the first administration. Dose calculations performed on the basis of a modified ICRP 30, Part 4 model yielded dose reductions (e.g. for subject A) of 90%, 28%, 28% and 26% for liver, bone surfaces, red bone marrow and lungs, respectively, corresponding to a reduction of the effective dose equivalent of approximately 40%. (author)

  14. Distribution of 241Am in offspring from BALB/c mice injected with 241Am at 14 days of gestation: relation to calcium and iron metabolism and comparison with distribution of 241Am after injection of adults

    Pregnant mice were given intravenous injections of 241 Am citrate at 14 days of gestation. The fetal skeleton had a higher or similar uptake of 241Am per gram of fresh tissue than the liver. The liver in adults concentrated 5 to 20 times more 241 Am per gram of fresh tissue than the bones. Measurement of changes in calcium and iron content and concentration with time, showed that in developing mice intensive calcification of bones determined uptake of 241Am. The 241Am uptake was related to calcium concentration of the fetal bones, which was greater at 14 days of gestation in the anterior bones, mandibles and calvaria, than in ribs and femurs. Transfer of 241Am to pups via milk resulted in further accumulation of 241Am in skeleton and liver. The incorporation in the skeleton persisted after weaning and contributed to the lifetime body burden. The 241Am concentration decreased rapidly with time after injection in relation to growth of the organs. Radiation dose rates and cumulative radiation doses were calculated for liver and bones of contaminated offspring. (author)

  15. Separation and determination of 241Am in urine samples from radiation workers using PC88-A and alpha spectrometry

    Bioassay technique is used for the estimation of actinides present in the body based on their excretion rate through body fluids. For occupational radiation workers urine assay is the preferred method for monitoring of chronic internal exposure. Determination of low concentrations of actinides such as plutonium, americium and uranium at low level of mBq in urine by alpha spectrometry requires pre-concentration of large volumes of urine. This article deals with standardization of analytical method for the determination of 241Am isotope in urine samples using Extraction Chromatography (EC) and 243Am tracer for radiochemical recovery. The method involves oxidation of urine followed by co-precipitation of americium along with calcium phosphate. This precipitate after treatment is further subjected to calcium oxalate co-precipitation. Separation of Am was carried out by EC column prepared by PC88-A (2-ethyl hexyl phosphonic acid 2-ethyl hexyl monoester) adsorbed on microporous resin XAD-7 (PC88A-XAD7). Am-fraction was electro-deposited and activity estimated using tracer recovery by alpha spectrometer. Ten routine urine samples of radiation workers were analyzed and consistent radiochemical recovery was obtained in the range 44-60% with a mean and standard deviation of 51 and 4.7% respectively. (author)

  16. Preparation and high intensity heavy ion irradiation tests of intermetallic 243Am/Pd targets

    Previously reported preparation method for Pd-based intermetallic targets (Usoltsev, et al., 2012) [1] has been successfully applied for producing two stationary 243Am/Pd targets. Both targets have been irradiated at the U-400 cyclotron at Flerov Laboratory of Nuclear Reactions Dubna (Russian Federation) using high intensity beams (up to 0.83 μApart) of 48Ca18+. Alpha-particle spectroscopy and light microscopy allowed for a comprehensive characterization of the intermetallic targets before and after irradiation. A natNd/Pd intermetallic target and a solely electroplated 243Am/Ti target were similarly investigated for comparison

  17. Recovery of 241Am/Be neutron sources, Wooster, Ohio

    In August 1997, the Nuclear Regulatory Commission (NRC) submitted to the US Department of Energy (DOE) a partial list of licensed radioactive sealed sources to be recovered under a pilot project initiating Radioactive Source Recovery Program (RSRP) operations. The first of the pilot project recoveries was scheduled for September 1997 at Eastern Well Surveys in Wooster, Ohio, a company with five unwanted sealed sources on the NRC list. The sources were neutron emitters, each containing 241Am/Be with activities ranging from 2.49 to 3.0 Ci. A prior radiological survey had established that one of these sources, a Gulf Nuclear Model 71-1 containing 3 Ci of 241Am, was contaminated with 241Am and might be leaking. The other four sources were obsolete and could no longer be used by Eastern Well Surveys for their intended application in well-logging applications due to NRC decertification of these sources. All of the sources exceeded the limits established for Class C waste under 10 CFR 61.55 and, as a result, are the ultimate responsibility of the DOE under the provisions of PL 99-240. This report describes the cooperative effort between the DOE and NRC to recover the sources and transport them to Los Alamos National Laboratory (LANL) for deactivation under the RSRP. This operation alleviated any potential risk to the public health and safety from the site which might result from the leaking neutron sources or the potential mismanagement of unwanted sources. The on-site recovery occurred on September 23, 1997, and was performed by personnel from LANL and its contractor and was observed by staff from the Region III office of the NRC. All aspects of the recovery were successfully accomplished, and the sources were received at LANL on September 29, 1997. Experience gained during this operation will be used to formulate operational poilicies and procedures which will contribute to the eventual routine recovery operations of a full-scale RSRP

  18. A case of occupational internal contamination with 241Am

    An internal contamination with 241Am was detected in a worker during a routine monitoring of workers from a company producing Am sources for smoke detectors and Am-Be neutron sources. During the 4-year period after the exposure, the number of urine and faecal samples from the worker were analysed; in vivo measurements were also performed. Specific values for absorption parameters of the human respiratory tract model and particle transport values were applied to improve the model fit to the measurement data. A good agreement of the bioassay data with the so-modified model predictions was obtained. (authors)

  19. Electronic structure of polycrystalline Cd metal using 241Am radioisotope

    Dhaka, M. S.; Sharma, G.; Mishra, M. C.; Sharma, B. K.

    2014-04-01

    Electronic structure study of the polycrystalline cadmium metal is reported. The experimental measurement is undertaken on a polycrystalline sheet sample using 59.54 keV radioisotope of 241Am. These results are compared with the ab initio calculations. The theoretical calculations are performed using linear combination of atomic orbitals (LCAO) method employing the density functional theories (DFT) and Hartree-Fock (HF) and augmented plane wave (APW) methods. The spherically averaged APW and LCAO based theoretical Compton profiles are in good agreement with the experimental measurement however the APW based theoretical calculations show best agreement.

  20. Electronic structure of polycrystalline Cd metal using 241Am radioisotope

    Electronic structure study of the polycrystalline cadmium metal is reported. The experimental measurement is undertaken on a polycrystalline sheet sample using 59.54 keV radioisotope of 241Am. These results are compared with the ab initio calculations. The theoretical calculations are performed using linear combination of atomic orbitals (LCAO) method employing the density functional theories (DFT) and Hartree-Fock (HF) and augmented plane wave (APW) methods. The spherically averaged APW and LCAO based theoretical Compton profiles are in good agreement with the experimental measurement however the APW based theoretical calculations show best agreement

  1. Preliminary investigation on biosorption mechanism of 241Am by Rhizopus arrhizus

    As an important radioisotope in nuclear industry and other fields, 241Am is one of the most serious contamination concerns due to its high radiation toxicity and long half-life. Encouraging biosorption of 241Am from aqueous solutions by free or immobilized Rhizopus arrhizus (R. arrhizus) has been observed in our experiments. In this study, the preliminary evaluation on the mechanism was further explored via chemical or biological modification of R. arrhizus using europium as a substitute for americium. The results indicated that in approximately 48 hours R. arrhizus was able for efficient adsorption of 241Am. The pH value of solutions decreased gradually with the uptake of 241Am by R. arrhizus, implying that H+ was released from R. arrhizus via ion-exchange. The biosorption of 241Am by the decomposed cell wall of R. arrhizus was as efficient as by the intact fungus. The adsorption ratio for 241Am by deacylated R. arrhizus dropped, implying that carboxyl functional groups of R. arrhizus play an important role in the biosorption of 241Am. Most of the investigated acidic ions have no significant influence on the adsorption of 241Am, while saturated EDTA can strongly inhibit the biosorption of 241Am by R. arrhizus. When the concentrations of coexistent Eu3+, Nd3+ were 300 times more than that of 241Am, the adsorption ratios would decrease to about 86% from more than 99%. It could be noted by transmission electron microscope (TEM) analysis that the adsorbed Eu is scattered almost in the whole fungus, while Rutherford backscattering spectrometry (RBS) indicated that Ca in R. arrhizus have been replaced by Eu via ion-exchange. The change of the absorption peak structure in the IR spectra implied that there was complexation between metals and microorganism. The results implied that the adsorption mechanism of 241Am by R. arrhizus is very complicated involved ion-exchange, complexation process as well as nonspecific adsorption in the cell wall by static electricity. (author)

  2. A Method for Specific Activity Measurement of 241Am Solution

    According to the principle of coincidence theory, the specific activity of 241Am solution was determined on 4πα+4πγ counting standard device by γ efficiency extrapolation, and the problems of constant correction coefficients of self-absorption and scattering in α ionization chamber method were solved. The method was based on the alteration of detection efficiency when the height of elevator was altered, and the activity was obtained by γ fitting extrapolation according to detection efficiency. The results of more than 20 alpha radioactive sources by this method in our work are accordant with those of 2πα ionization chamber, and their uncertainties are improved to 0.4%. (authors)

  3. Biosorption of 241Am by Rhizopus arrihizus: preliminary investigation and evaluation

    The biosorption of 241Am from solution by a fungus--Rhizopus Arrihizus (R. arrihizus), and the effect of experimental conditions on the adsorption were investigated. The preliminary results showed that the biosorption of 241Am by R. arrihizus is very efficient. An average of more than 99% of the total 241Am was removed by R. arrihizus of 1.3 g/l (dry weight) from 241Am solutions of 5.6-111 MBq/l (44.3-877.2 μg/l) (C0), with adsorption capacities (W) of 4.2-79.4 MBq/g biomass (dry weight) (33.2-627.5 μg/g). The biosorption equilibrium was achieved within 1 h and the optimum pH ranged from 1 to 3. No significant differences in 241Am biosorption were observed at 10-45 deg. C, or in solutions containing Au3+ or Ag+, even 2000 times above 241Am concentration. The relationship between concentrations and adsorption capacities of 241Am indicated that the 241Am biosorption by R. arrihizus obeys the Freundlich adsorption equation

  4. Distribution of 241Am in the human body as determined by external counting

    Methods for determining the distribution of 241Am within the body of a contaminated subject and their application to several cases under study at the Center for Human Radiobiology are described. In general, 241Am is found in the lungs even at long times after inhalation, and systemic 241Am is observed to deposit in the liver and to label the skeleton in a fairly uniform manner; similar findings have been reported in animal studies (L172). Further analysis of the skeletal distribution of 241Am indicates deposition on bone surfaces. In contrast, the distribution of injected 239Pu in an (abnormal) skeleton is rather non-uniform when compared to that of 241Am

  5. Measurements of neutron cross section of the {sup 243}Am(n,{gamma}){sup 244}Am reaction

    Hatsukawa, Yuichi; Shinohara, Nobuo; Hata, Kentaro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    The effective thermal neutron cross section of {sup 243}Am(n,{gamma}){sup 244}Am reaction was measured by the activation method. Highly-purified {sup 243}Am target was irradiated in an aluminum capsule by using a research reactor JRR-3M. The tentative effective thermal neutron cross sections are 3.92 b, and 84.44 b for the production of {sup 244g}Am and {sup 244m}Am, respectively. (author)

  6. Biosorption of 241Am by Saccharomyces cerevisiae. Preliminary investigation on mechanism

    As an important radioisotope in nuclear industry and other fields, 241Am is one of the most serious contamination concerns due to its high radiation toxicity and long half-life. The encouraging biosorption of 241Am from aqueous solutions by free or immobilized Saccharomyces cerevisiae (S. cerevisiae) has been observed in our previous experiments. In this study, the preliminary evaluation on mechanism was further explored via chemical or biological modification of S. cerevisiae, and using europium as a substitute for americium. The results indicated that the culture times of more than 16 hours for S. cerevisiae was suitable and the efficient adsorption of 241Am by the S. cerevisiae was able to achieve. The pH value in solutions decreased gradually with the uptake of 241Am in the S. cerevisiae, implying that H+ released from S. cerevisiae via ion-exchange. The biosorption of 241Am by the decomposed cell wall, protoplasm or cell membrane of S. cerevisiae was same efficient as by the intact fungus. However, the adsorption ratio for 241Am by the deproteinized or deacylated S. cerevisiae dropped obviously, implying that protein or carboxyl functional groups of S. cerevisiaece play an important role in the biosorption of 241Am. Most of the investigated acidic ions have no significant influence on the 241Am adsorption, while the saturated EDTA can strong inhibit the biosorption of 241Am on S. cerevisiae. When the concentrations of coexistent Eu3+, Nd3+ were 100 times more than that of 241Am, the adsorption ratios would decrease to 65% from more than 95%. It could be noted by transmission electron microscope (TEM) analysis that the adsorbed Eu is almost scattered in the whole fungus, while Rutherford backscattering spectrometry (RBS) analysis indicated that Ca in S. cerevisiae have been replaced by Eu via ion-exchange. All the results implied that the adsorption mechanism of 241Am on S. cerevisiae is very complicated and at least involved in ion exchange, complexation

  7. 241Am distribution in foetal haemopoietic organs of Balb/c mice

    Developing haemopoietic organs and the fetal skeleton are considered target organs after internal contamination of the mother with actinides. Pregnant Balb/c mice were injected with 14 kBq 241Am citrate at day 14 of gestation, at the time haematopoiesis rises in the foetal liver. The 241Am retention was measured between one day after injection until 3 months after birth. The activities of 241Am in carcass and liver were measured by gamma-counting in a NaI (Tl) well-type crystal, skeletal parts and intestinal tract were measured by alpha-counting in a ZnS counter. Liver and skeleton concentrated 241Am but in the skeleton the 241Am concentration varied considerably between various parts: e.g. mandible and calvarium showed a 5 fold higher 241Am concentration compared to the femur. Comparison was made between mice which stayed with their mother till 3 weeks after birth and mice which received a foster-mother, this allows to calculate the importance of the maternal contamination via milk to the dose of the young mice. The retention data were used to calculate initial dose rates and absorbed radiation doses in function of time in the organs at risk. 15 refs.; 1 figure; 2 tabs

  8. Influence of organic fertilization on the sorption mechanisms of 241 Am in tropical soils

    In this work the mechanisms involved in the sorption of 241Am were investigated depending on the physicochemical properties of some Brazilian soils and on alterations promoted by organic amendment. This experimental study was conducted in a controlled area, where pots containing different kinds of soils (histisol, ferralsol and nitisol), with different organic amendment doses (without amendment; 2 kg m-2 and 4 kg m-2) were artificially contaminated by radioactive solution water, which contained 241Am. Migration studies, distribution (or partition) coefficient (KJ), bioavailability and organic matter were carried out in these soils, with ar without organic amendment. In order to evaluate the effective bioavailability of radionuclides, radish (Raphanus sativus L.) was cultivated in these pots, and later the concentration of 241Am in radish's roots was measured. The main results show that 241Am tends to be strongly attached to organic matter and that organic amendment in tropical soils minimizes the radionuclide studied desorption. Also, distribution (or partition) coefficient values for 241Am were generated and these values are smaller than those ones determined for soils from temperate zones. Physical and chemical fractioning of organic matter were carried out. (author)

  9. Measurement and analysis of the $^{243}$Am neutron capture cross section at the n_TOF facility at CERN

    Mendoza, E; Guerrero, C; Berthoumieux, E; Abbondanno, U; Aerts, G; Alvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Balibrea, J; Baumann, P; Becvar, F; Belloni, F; Calvino, F; Calviani, M; Capote, R; Carrapico, C; Carrillo de Albornoz, A; Cennini, P; Chepel, V; Chiaveri, E; Colonna, N; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Dolfini, R; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Ferrant†, L; Ferrari, A; Ferreira-Marques, R; Fitzpatrick, L; Frais-Koelbl, H; Fujii, K; Furman, W; Goncalves, I; Gonz alez-Romero, E; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Isaev, S; Jericha, E; Kappeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Ketlerov, V; Kerveno, M; Koehler, P; Konovalov, V; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lossito, R; Lozano, M; Lukic, S; Marganiec, J; Marques, L; Marrone, S; Martınez, T; Massimi, C; Mastinu, P; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O’Brien, S; Oshima, M; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rosetti, M; 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; Vicente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K

    2014-01-01

    Background:The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties of minor actinides. Purpose: Reduce the $^{243}$Am(n,$\\gamma$) cross section uncertainty. Method: The $^{243}$Am(n,$\\gamma$) cross section has been measured at the n_TOF facility at CERN with a BaF$_{2}$ Total Absorption Calorimeter, in the energy range between 0.7 eV and 2.5 keV. Results: The $^{243}$Am(n,$\\gamma$) cross section has been successfully measured in the mentioned energy range. The resolved resonance region has been extended from 250 eV up to 400 eV. In the unresolved resonance region our results are compatible with one of the two incompatible capture data sets available below 2.5 keV. The data available in EXFOR and in the literature has been used to perform a simple analysis above 2.5 keV. Conclusions: The results of this measurement contribute to reduce the $^{243}$Am(n,$\\gamma$) cross section uncertainty and suggest that this cross section is underestimate...

  10. $^{241}$Am: a difficult actinide for (n,$\\gamma$) cross section measurement

    Rossbach, M

    2014-01-01

    Many attempts have been made in the past to determine accurate cross section data for neutron capture in $^{241}$Am, however, the reported data for thermal neutron energies scatter by more than 25% around 680 b. The situation is complicated as the product of the capture reaction is twofold: $^{241}$Am (n,$\\gamma$)$^{242g}Am,^{242m}$Am. The production ratio for ground- and metastable state is uncertain but also $^{241}$Am exhibits a very low first resonance at about 0.3 eV and this might influence the 1/v behaviour at thermal energy, 0.025 eV. In our experiments, we are using cold neutrons at the PGAA facilities of the Budapest and Garching Research Reactors, hence, we assume to be independent of the perturbations from possible non-1/v behaviour.

  11. Accumulation of 241Am by suspended matter, diatoms and aquatic weeds of the Yenisei River

    In this work we experimentally estimated the capacities of the key components of the Yenisei River (Russia): particulate suspended matter (seston), diatom microalgae, and submerged macrophytes for accumulating 241Am from water. In our experiments large particles of seston (>8 μm), comparable in size with diatoms, took up most of americium from water. The accumulation of americium by isolated diatom algae (Asterionella formosa and Diatoma vulgare) was lower than by total seston. The concentration factors (CFs) of 241Am for seston of the Yenisei River in our experiments were (2.8-6.9).105; for diatoms - (1.5-4.2).104. The CFs for aquatic plant Elodea canadensis were within the same order of magnitude as those for diatoms. Activity concentration and CFs of 241Am were nearly the same in experiments under dark and light conditions. This is indicative of an energy independent mechanism of americium uptake from the water by diatoms and submerged macrophytes.

  12. Adsorption of 241Am and 226Ra from natural water by wood charcoal

    The adsorption of 241Am and 226Ra from natural water by a granulated wood charcoal was investigated as a function of the solution pH, in the range 4-10, and of the water flow, in the range 3.5-42 cm3/min. The percentage adsorption of 241Am (fairly constant at >80% for all pHs) was greater than that of 226Ra (which increased with increasing pH from ∼40% up to >80%). The results are explained by considering the different species of each radionuclide present at the pH values of the solution at the end of the adsorbent column, and the pH of the point of zero charge of the adsorbent. At pH 6, the elimination of 241Am from natural water was independent of the water flow, while the elimination of 226Ra declined linearly as the flow rate was increased

  13. Fast Neutron Imaging Using 241Am-Be Neutron Source%241Am-Be中子源快中子成像研究

    蒋诗平; 陈亮; 万里飚; 杜淮江; 范扬眉; 韩荣典

    2007-01-01

    中子成像是一种与X射线成像互补的无损探测技术.为探索同位素中子源用于发展可移动的无损检测系统,利用241Am-Be作为中子源,使用自制的中子发光转换屏和X射线胶片作为探测系统开展了快中子成像研究,并获得了较高质量的图像.研究结果表明,利用241Am-Be中子源发展小型探测系统是有潜力的.

  14. Bonner sphere measurements of 241Am-B and 241Am-F neutron energy spectra unfolded using high-resolution a priori data

    High-resolution neutron energy spectra, covering the entire energy range of interest, for two standard radionuclide neutron sources (241Am-B and 241Am-F) have been derived from Bonner sphere measurements by using high-resolution a priori data in the unfolding process. In each case, two a priori spectra were used, one from a two-stage calculation and also one from a combination of the calculated spectrum with a high-resolution measured spectrum. The unfolded spectra are compared with those published elsewhere and show significant differences from the ISO- and IAEA-recommended spectra for 241Am-B and 241Am-F, respectively. Values for the fluence-average energy and fluence-to-dose-equivalent conversion coefficients are presented for the new spectra, and the implications of the new spectra for the emission rates of the sources when measured by the manganese bath technique are also determined. A combination of calculations and measurements has been performed to determine the spectral fluence from two reference neutron sources over the entire energy range of interest. For the Am-B source, this approach has supported the spectra of Marsh et al. and Zimbal and reduced confidence in the ISO 8529 spectrum. However, in terms of derived quantities, there is a good agreement between all the available spectra. In contrast, the new Am-F spectrum presented here is significantly different from those already published. The fluence to dose conversion coefficients derived from the new spectrum are 9 % lower than the currently accepted values, and the emission rates of Am-F sources measured by the manganese bath technique may need to be increased by up to 0.5 %. (authors)

  15. Uncertainty of the estimation of 241Am content of the human body

    The aim of the study was to make a realistic estimation of 241Am activity in the body of the people with old internal contamination. A whole-body counter equipped with HPGe and LEGe detectors was used as a major tool. Calibration was performed using phantoms of the human head, knee, arm and leg of different origin. Using it for the evaluation of 241Am in the body of an internally contaminated case, body activity was estimated to be 5.6 kBq and its uncertainty was in the range given by factor 1.5 ± 1. (author)

  16. Transport parameters of 241 Am from low and intermediate level radioactive waste in disposal surroundings

    A programme on the safety analysis linked to the geological disposal of radioactive wastes is under study at the Institute for Nuclear Research Pitesti. In relation to the migration of radionuclides in the terrestrial environment following a possible release from the repository, specific experimental studies have been developed in order to provide the necessary input data for the risk assessment models. The paper reports the results of studies performed with 241 Am. Laboratory experiments were conducted to determine the transport parameters of 241 Am in the geological formations of Saligny site - the potential near-surface repository for low and intermediate radioactive wastes in Romania. (authors)

  17. Evolution of late blood damage from decreasing doses of 241Am following injection in the rat

    Rats were given intravenous or intramuscular injections of 241Am at decreasing doses ranging from 7.5 μCi to 0.075 μCi per kg of body weight. Blood examinations showed that higher doses exerted an irreversible destructive effect on all blood cells. As the administered doses decreased, the destructive effect of 241Am dropped and even became reversible for white cells. Proliferative disorders such as leukocytosis with myelemias, leukemias -chiefly acute or chronic granulocytic leukemias- were then demonstrated. Red cells only dropped but more and more slowly. At the lowest doses, life-span shortening was the most evident effect

  18. Theoretical L X-ray emission probabilities in the decay of 241Am

    L X-rays emitted in the decay of 241Am are widely used for the calibration of X-ray detectors. Many measurements of the X-ray intensities in this decay have been made, however detailed balancing of the decay scheme has not yet been successful. This work attempts balancing of the decay scheme. The balance does not work with published values of fluorescence yields and Coster-Kronig transition probabilities but produces a better balance than previous studies and also shows the possibility of problems due to chemical effects with 241Am as a standard. (orig.)

  19. A feasibility study for transportable 241Am-in-lung and 241Am-in-nose-blow monitoring systems for use following a weapons accident

    In a nuclear weapon accident involving fire or conventional explosion, most of the radiation dose received by people in the immediate vicinity would result from inhalation of 239Pu. This is accompanied by the nuclide 241Am, which is much easier to determine by external counting because of the 60 keV gamma ray emission. In the event of an accident, a priority would be to identify any people who have had intakes of 239Pu which were so large that decorporation therapy should be considered. Direct measurement of lung content provides the most rapid and convenient method for assessing intakes by inhalation. A transportable system has been considered as this could be deployed close to the site of the accident and would allow rapid measurements to be made. The feasibility of a transportable 241Am-in-nose-blow and nasal swab measurement system has also been considered. This would be used to help select people for 241Am-in-lung measurements. (author)

  20. Effects of the herbicide glyphosate on the uptake of 239Pu and 241Am to vegetation

    Glyphosate (n-phosphonomethyl glycine) is a broad spectrum herbicide widely used in lowland agriculture, forestry and improved upland pastures. Although its metal chelating properties are well established, its interaction with radionuclides remains unknown. A pot experiment was conducted to determine the effect of soil applications of glyphosate on the uptake of 239Pu and 241Am to peas and carrots grown in loam, peat and sand soils. Soil-to-plant transfer factors were calculated for treated and untreated soils at harvest. The most marked effect was an increase in 241Am uptake to crops grown in loam soil. Supplementary laboratory batch experiments were conducted by shaking radiolabelled soil and its associated soil solution with glyphosate. The activity concentration of 241Am increased ten fold in the liquid phase of loam soils treated with glyphosate. It is postulated that this 241Am desorption could have been mediated by the formation of a stable Am-glyphosate complex which was subsequently more available for crop uptake than Am alone. (author)

  1. 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.)

  2. Disposition of 241AmO2 following inhalation by beagle dogs

    Translocation of 241Am from the lungs of beagles following inhalation of AmO2 was fairly rapid, roughly equal quantities being found in the liver and skeleton at all postexposure times to 810 days. Less than 16 percent of the initial body burden was excreted, more than two-thirds of this in the feces

  3. Spatial statistical analysis of contamination level of 241Am and 239Pu, Thule, North-West Greenland

    Strodl Andersen, J. (JSA EnviroStat (Denmark))

    2011-10-15

    A spatial analysis of data on radioactive pollution on land at Thule, North-West Greenland is presented. The data comprises levels of 241Am and 239,240Pu on land. Maximum observed level of 241Am is 2.8x105 Bq m-2. Highest levels were observed near Narsaarsuk. This area was also sampled most intensively. In Groennedal the maximum observed level of 241Am is 1.9-104 Bq m-2. Prediction of the overall amount of 241Am and 239,240Pu is based on grid points within the range from the nearest measurement location. The overall amount is therefore highly dependent on the model. Under the optimal spatial model for Narsaarsuk, within the area of prediction, the predicted total amount of 241Am is 45 GBq and the predicted total amount of 239,240Pu is 270 GBq. (Author)

  4. Development of an 241Am applicator for intracavitary irradiation of gynecologic cancers.

    Nath, R; Peschel, R E; Park, C H; Fischer, J J

    1988-05-01

    Sealed sources of 241Am that emit primarily 60 keV photons produce relative dose distributions in water comparable to those from 137Cs or 226Ra sources and can produce dose rates of up to 100 cGy/hr at 1 cm in water. Also, 241Am gamma rays can be effectively shielded by thin layers of high atomic number materials (HVL is 1/8th mm of lead) placed on the applicator or inside some body cavities (for example, hypaque in bladder, barium sulphate in rectum). These properties of 241Am sources open a new approach to optimizing intracavitary irradiation of various cancers by allowing a reduction in dose and volume of irradiated critical organs or by increasing tumor doses. The relative ease with which highly effective shielding is achievable with 241Am sources would allow the design and fabrication of partially shielded applicators which can produce asymmetric dose distributions to allow unidirectional irradiation of localized lesions. Design and dosimetry characteristics of a gynecological applicator containing 241Am sources are presented. The applicator consists of a 2, 3, or 4 segment vaginal plaque (loaded with 2 and 5 Ci 241Am sources) and a tandem made up of a single 8 Ci 241Am source. Dose rates at 2 cm from the plaques are 42.0, 47.4, 58.3 and 56.7 cGy/hr for 5-5, 5-4-5, 5-5-5, and 5-4-4-5 Ci plaques, respectively. The 5-4-5 Ci plaque in combination with the 8 Ci tandem produces dose rates of 60.0 and 22.8 cGy/hr to points A and B, respectively. Surface dose rates on the plaque applicators are 143, 124, 142 and 132 cGy/hr for 5-5, 5-4-5, 5-5-5 and 5-4-4-5 Ci applicators, respectively. The shielding effect of a 0.5 mm thick lead foil on one side of the 5-4-5 Ci applicator is found to be a factor of 16.8; for example, the dose rate at 2 cm from the unshielded side is 42.0 cGy/hr compared to a dose rate of 2.5 cGy/hr at 2 cm from the shielded side. Initial clinical experience with this applicator in the treatment of recurrent gynecological lesions is also presented

  5. Re-evaluation of neutron nuclear data for 242mAm, 243Am, 99Tc and140Ce

    The evaluated nuclear data given in JENDL-3.2 were compared with other evaluated data sets and available experimental data, for important minor actinides of 242mAm and 243Am, and fission product nuclides of 99Tc and 140Ce. Since problems were found as a result of the comparison, the data of JENDL-3.2 were improved for these nuclides. It was found that the evaluated data of Maslov et al. were superior to the others. They were adopted for 242mAm and 243Am after further improvements. For 99Tc and 140Ce, resonance parameters and optical model parameters were improved. The cross sections of these two nuclides in the smooth part were re-calculated. The present results were given in the neutron energy range from 10-5 eV to 20 MeV in the ENDF-6 format, and adopted to JENDL-3.3. (author)

  6. Proposed retention model for human inhalation exposure to 241AmO2

    A dosimetry model based on a four-year study in Beagle dogs was developed to predict patterns of absorbed radiation doses for people exposed by inhalation to 241AmO2. Following a single inhalation exposure to one of three sizes of monodisperse or a polydisperse aerosol of 241AmO2, pairs of dogs were sacrificed at 8, 32, 64 and 256 days, and 2 and 4 years. For about 80% of the initial lung burden, the retention halftimes were 11, 18, 26 and 27 days for the 0.75, 1.5 and 3.0 μm aerodynamic diameter and the 1.8 μm activity median aerodynamic diameter aerosols, respectively. For the remaining 20% of the initial lung burden, the retention halftimes were between 200 to 300 days with no apparent particle size influence. Additional 241Am metabolic studies reported in the literature using inhalation exposure or injection of the citrate complex were synthesized in the model as were eleven reported cases of human inhalation exposure. This model is compared to the ICRP II and TGLD lung models, both developed by analogy to Pu metabolism. The proposed model differs from these latter models in two important areas: (a) lung retention of 241AmO2 could not be adapted to the classifications used in these models, and (b) the fractional translocation from lung to other organs is 2 to 8 times larger. These factors considerably alter the predicted radiation dose distribution among organs and lead to the conclusion that derived radiation protection standards for 241AmO2 inhalation exposure should be modified. (author)

  7. Removal of inhaled 241Am oxide particles of various sizes from beagle dogs using lung lavage and chelation treatment

    The combined treatments of lung lavage and chelation therapy were evaluated for the removal of inhaled 241AmO2 aerosols in Beagle dogs. Groups 1 to 3 were exposed to monodisperse particles of 241AmO2 of 0.75, 1.5 and 3.0 μm aerodynamic diameter (AD) respectively; a fourth group was exposed to polydisperse particles of 241AmO2 with an activity median aerodynamic diameter (AMAD) of 1.8 μm. Treatment consisted of 5 lung lavages of the right and left lungs. Treated dogs were also given 18 intravenous injections of DTPA. The dogs were sacrificed 64 days after inhalation exposure. The amount of 241Am removed from lung in the lavage fluid for Groups 1 to 4 represented 41, 46, 42 and 33 % of the initial lung burden, respectively. The amount of 241Am excreted in the urine from the treated dogs in excess of that excreted by the untreated dogs for Groups 1 to 4 was 20, 19, 8 and 26 %, respectively. More 241Am was excreted in the urine from dogs that inhaled smaller particle sized aerosols. As a result of the removal of 241Am activity, the 64-day cumulative absorbed radiation doses to lung, liver and skeleton were reduced by 50, 90 and 85 %, respectively. (author)

  8. Effects of naturally occurring aquatic organic fractions on 241Am uptake by Scenedesmus obliquus (Chlorophyceae) and Aeromonas hydrophila (Pseudomonadaceae)

    Naturally occurring organics were extracted from water collected from Skinface Pond near Aiken, S.C. Organics were separated into four nominal diameter size fractions (I, greater than 0.0183; II, 0.0183 to 0.0032; III, 0.0032 to 0.0009; IV, less than 0.0009 μm) by membrane ultrafiltration and introduced into Scenedesmus obliquus and Aeromonas hydrophila cultures to determine their effects on 241Am availability for uptake. Effects on 241Am uptake were determined in actively growing S. obliquus cultures after 96 h of growth and in dense cultures of nongrowing cells after 4 h. Uptake by A. hydrophila was determined after 4 and 24 h in actively growing cultures. All organic fractions stimulated S. obliquus growth, with the most pronounced effects due to larger organic fractions, whereas no apparent growth stimulation of A. hydrophila was observed for any organic fraction. For both long-term and short-term studies, cellular 241Am concentration (picocuries/cell) increased with increasing 241Am concentration for S. obliquus and A. hydrophila. Fraction IV increased 241Am uptake by both S. obliquus and A. hydrophila during 4-h incubations. During 96-h incubations fraction I was flocculated and cosedimented, with S. obliquus and A. hydrophila cells causing an apparent increase in 241Am uptake. Fractions II and III reduced apparent 241Am uptake by S. obliquus as a result of biological dilution caused by increased algal growth due to the organics. Fraction IV caused a reduction in 241Am uptake by S. obliquus not attributable to biological dilution. Organics increased 241Am uptake by A. hydrophila during 4- and 24-h incubations. A. hydrophila also caused flocculation of fraction I during 96-h incubations

  9. Radiochemical determination of the neutron capture cross sections of {sup 241}Am irradiated in the JMTR reactor

    Shinohara, N.; Hatsukawa, Y.; Hata, K.; Kohno, N. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    The thermal neutron capture cross section {sigma}{sub 0} and Resonance integral I{sub 0} of {sup 241}Am leading to the production of {sup 242m}Am and {sup 242g}Am were measured by radiochemical method. The cross sections obtained in this study are {sigma}{sub 0}=60.9 {+-} 2.6 barn, I{sub 0}=213 {+-} 13 barn for {sup 241}Am(n,{gamma}){sup 242m}Am and {sigma}{sub 0}=736 {+-} 31 barn, I{sub 0}=1684 {+-} 92 barn for {sup 241}Am(n,{gamma}){sup 242g}Am. (author)

  10. Standardization of 241Am by digital coincidence counting, liquid scintillation counting and defined solid angle counting

    Balpardo, C; Rodrigues, D; Arenillas, P

    2010-01-01

    The nuclide 241Am decays by alpha emission to 237Np. Most of the decays (84.6 %) populate the excited level of 237Np with energy of 59.54 keV. Digital Coincidence Counting was applied to standardize a solution of 241Am by alpha-gamma coincidence counting with efficiency extrapolation. Electronic discrimination was implemented with a pressurized proportional counter and the results were compared with two other independent techniques: Liquid Scintillation Counting using the logical sum of double coincidences in a TDCR array and Defined Solid Angle Counting taking into account activity inhomogeneity in the active deposit. The results show consistency between the three methods within a limit of a 0.3%. An ampoule of this solution will be sent to the International Reference System (SIR) during 2009. Uncertainties were analysed and compared in detail for the three applied methods.

  11. On a low intensity 241Am Compton spectrometer for measurement of electron momentum density

    B L Ahuja; N L Heda

    2007-05-01

    In this paper, a new design and construction of a low intensity (100 mCi) 241Am -ray Compton spectrometer is presented. The planar spectrometer is based on a small disc source with the shortest geometry. Measurement of the momentum density of polycrystalline Al is used to evaluate the performance of the new design. The measured profile is in good agreement with the existing theoretical data and our density functional calculations.

  12. Carcinogenic effects of the combined action of /sup 241/Am and. gamma. -radiation

    Filippova, L.G.; Buldakov, L.A.; Nifatov, A.P. (Institut Biofiziki, Moscow (USSR))

    In experiments on Wistar rats a study was made of the carcinogenic effects of the combined exposure to /sup 241/Am administered intrapertioneally (6.7 to 229.4 kBq/kg body weight) and external ..gamma..-radiation (/sup 137/Cs, 175 cGy). The occurrence of osteosarcoma, leucosis, skin and mammary tumors increased in the exposed animals. The combined irradiation produced an additive carcinogenic effect.

  13. Carcinogenic effects of the combined action of 241Am and γ-radiation

    In experiments on Wistar rats a study was made of the carcinogenic effects of the combined exposure to 241Am administered intrapertioneally (6.7 to 229.4 kBq/kg body weight) and external γ-radiation (137Cs, 175 cGy). The occurrence of osteosarcoma, leucosis, skin and mammary tumors increased in the exposed animals. The combined irradiation prodUced an additive carcinogenic effect

  14. Proton-induced fission on 241Am, 238U and 237Np at intermediate energies

    Deppman, A.; Andrade-II, E.; Guimaraes, V; Karapetyan, G. S.; Balabekyan, A. R.; Demekhina, N. A.

    2013-01-01

    Intermediate energy data of proton-induced fission on 241Am, 238U and 237Np targets were analysed and investigated using the computational simulation code CRISP. Inelastic interactions of protons on heavy nuclei and both symmetric and asymmetric fission are regarded. The fission probabilities are obtained from the CRISP code calculations by means of the Bohr-Wheeler model. The fission cross sections, the fissility and the number of nucleons evaporated by the nuclei, before and after fission, ...

  15. Factors influencing the chemical extractability of 241Am from a contaminated soil

    Factors influencing the extractability of 241Am from an artificially contaminated soil were investigated. This was done with an equilibrium batch technique using a CH3COOH-NH4OH and HNO3-NaOH extracting system. The influence of several soil components was determined indirectly by selectively removing them from the soil. The effect of water- and HCl-soluble salts and organic matter on 241Am extractability was small. The most marked effect was due to the soil organic fraction that was not water- or HCl-soluble. This organic fraction was influential under both low and high pH conditions, but its influence was particularly marked under low pH conditions. The free iron-oxides had an appreciable effect under low pH conditions, but no observable effect in the high pH range. Though to a lesser extent, the free silica and alumina, amorphous alumino-silicate, and possibly residual organic matter also showed some influence. These results provide some implications on the conditions that influence the movement of 241Am in soils and its availability to plants. A review of the literature on the behavior of Am in soils is included

  16. Isolating 241Am from waste solutions containing Al, Ca, Fe, and Cr

    About 2.4 kg of 241Am contaminated with calcium and aluminum had been recovered from low-activity waste during recycle of 11% 240Pu. A process was developed and demonstrated to purify the americium before shipment as 241AmO2. The americium and some of the calcium were batch extracted into 50% TBP-n-paraffin from 2.2M Al(NO3)3 - 0.3M HNO3 solution in a canyon tank. Pregnant solvent was scrubbed first with 2.1M Al3+-0.3M Li+-6.7M NO3- and then with 7M LiNO3 to reduce the calcium content and to displace the aluminum. Americium was then stripped from the solvent with water and concentrated by evaporation. Before precipitating the americium with oxalic acid, the nitric acid was adjusted with NH4OH to yield a 1M NH4NO3 solution. Recovery across the batch extraction step was 97.8%, while 93% of the calcium and >99% of the aluminum was rejected. Recovery across precipitation averaged >96% while producing a product which was >99.3% pure 241AmO2. The major impurities were water, carbon, calcium, iron, and zinc

  17. Exposure of workers from intakes of ''241Am in the Czech Republic

    Americium 241 has been used for many applications in the Czech republic since the end of the sixties. The original material was AmO2 powder, imported from the ten Soviet Union. Up to now, about 30 cases with ''241Am internal contamination had been identified. The intakes and commented effective doses have been calculated according to ICRP 78 biokinetic model for ''241Am of class M and AMAD 5μm, however, the agreement between intakes calculated from skeleton activities and activities in urine and faeces has not been very good. In the present paper, activities in skulls, obtained from in vivo measurements, were calculated suing efficiencies depending on the size of skull. The activity of ''241Am in skeleton and daily excreted activity of 3 voltammeters were fitted with ICRP 67 biokinetic models for classes M and S and AMAD values 1, 5, 10 and 20 μm. The best agreement in intakes calculated from individual data sets (skeleton, urine, faces) was obtained for the class M and AMAD 10 μm. (Author) 16 refs

  18. Exposure of workers from intakes of ''241Am in the Czech Republic

    Malatova, I.; Beckova, V.; Vrba, T.; Pospisilova, H.

    2004-07-01

    Americium 241 has been used for many applications in the Czech republic since the end of the sixties. The original material was AmO{sub 2} powder, imported from the ten Soviet Union. Up to now, about 30 cases with ''241Am internal contamination had been identified. The intakes and commented effective doses have been calculated according to ICRP 78 biokinetic model for ''241Am of class M and AMAD 5{mu}m, however, the agreement between intakes calculated from skeleton activities and activities in urine and faeces has not been very good. In the present paper, activities in skulls, obtained from in vivo measurements, were calculated suing efficiencies depending on the size of skull. The activity of ''241Am in skeleton and daily excreted activity of 3 voltammeters were fitted with ICRP 67 biokinetic models for classes M and S and AMAD values 1, 5, 10 and 20 {mu}m. The best agreement in intakes calculated from individual data sets (skeleton, urine, faces) was obtained for the class M and AMAD 10 {mu}m. (Author) 16 refs.

  19. Plutonium, 90Sr and 241Am in human bones from southern and northeastern parts of Poland

    The paper presents the results of our study on 238Pu, 239Pu, 240Pu, 241Am and 90Sr concentration in human bones carried out on a set of 88 individual samples of central Europe origin. Bone tissue samples were retrieved under surgery while introducing hip joint implants. The conducted surgeries tend to cover either southern or northeastern parts of Poland. While for the southern samples only global fallout was expected to be seen, a mixed global and Chernobyl fallout were to be reflected in the others. Alpha spectrometry was applied to obtain activity concentration for 238Pu, 239+240Pu, 241Am, while liquid scintillation spectrometry for 90Sr and mass spectrometry to receive 240Pu/239Pu mass ratio. Surprisingly enough, and to the contrary to our expectations we could not see any significant differences in either Pu activity or Pu mass ratio between the studied populations. In both populations Chernobyl fraction proved marginal. The results on 90Sr and 241Am confirm similarities between the two examined groups. (author)

  20. Calculation of anisotropy factors for 241Am-Be neutron sources

    The authors calculated anisotropy factors for 241Am-Be neutron sources used for calibration of neutron-measuring devices for radiation protection purpose. In this calculation, we created a calculation model composed of following three steps: (1) calculation of α-particle spectrum at the surface of spherical cluster of AmO2, (2) calculation of neutron yield in a thick beryllium target and of neutron spectrum produced by 8Be (α,n) reactions; and (3) calculation of angular fluence distribution of neutrons emerging from two different encapsulation types of 241Am-Be neutron sources. This computation was made by combining an in-house code using the 9Be(α,n) cross section data library (JENDL/AN-2005) and the Monte Carlo code MCNP-4C. As a result, anisotropy factors in the direction perpendicular to the source capsule axis were evaluated to be 1.030 and 1.039 for 241Am-Be in a standard Amersham X3 capsule and X4 capsule, respectively. These values are in reasonable close agreement with the published experimental data. If the support structures are included in the simulation, the anisotropy factors for these neutron sources increase by about 10%. (author)

  1. Investigations of the chemical forms of 239Pu and 241Am in estuarine sediments and a salt marsh soil

    Estuarine sediments and a salt marsh soil have been fractionated by non-destructive procedures. The distribution of 239Pu and 241Am in these fractions has been determined by gel permeation chromatography and extraction with complexing agents. (author)

  2. Dose distributions around cylindrical 241Am sources for a clinical intracavitary applicator

    Encapsulated, cylindrical sources containing 2, 5, and 8 Ci of 241Am have been designed and fabricated for intracavitary irradiation of uterine cancers. Exposure rates in air and dose rates in water around these sources have been measured using an ionization chamber and a lithium fluoride thermoluminescent dosimetry system. Dose rates in water at a distance of 2.5 cm from the source center along a direction transverse to the source axis were found to be 10.4, 24.3, and 23.3 cGy/h for the 2-, 5-, and 8-Ci sources, respectively, using an ionization chamber. Under the same conditions, the thermoluminescent dosimetry system yielded the values of 10.3, 23.1, and 22.3 cGy/h. It was observed that the ratio of dose-to-water and exposure in air is sensitive to the scattering geometry and source geometry in the case of 241Am photons. This ratio was found to increase substantially as conditions of full scattering were approached. A three-dimensional integration model was employed for the determination of dose distributions around these sources. Results of this dose computation model have been compared against the measured data and were found to be in good agreement with each other. Average deviations of calculated data from measured data were in the range of 0.2 to 0.5 cGy/h and larger deviations were observed in the paraxial region, where the effects of oblique filtration are more severe. Computed dose rate tables were employed as reference source data in a modified version of a commercial treatment planning system in order to develop a facility for clinical dosimetry of 241Am intracavitary applications

  3. Enhanced removal of 241Am by DTPA chelation therapy in an adult and teenage subject

    A series of Na3 (Ca-DTPA) chelation treatments were carried out on two human subjects, an adult man and a teenage boy, who have long-term body burdens of 241Am. The in vivo whole-body counting, bioassay of urine and feces, and various blood chemistry measurements were coordinated to coincide with this therapy schedule. Decreases in total body burdens for this treatment period were measured as 5 percent in the adult and 30 percent in the youth. High concentrations of zinc in urine and a corresponding decrease of activity of the zinc-dependent erythropoietic enzyme, ALAD, were also observed. (U.S.)

  4. A comparison of Ca-DTPA and Zn-DTPA for chelating 241Am in beagles

    Results of a comparative study of the efficiency of removing body burdens of 241Am in beagles subjected to chelation therapy with either Ca-DTPA or Zn-DTPA are given. It is shown that on an equimolar basis the efficacy of the calcium salt is not greater than the zinc salt for treatments begun 2 weeks after radionuclide injection. The authors suggest that due to the much greater toxicity which has been shown for Ca-DTPA, it appears that Zn-DTPA should replace Ca-DTPA as treatment of choice in human cases. (U.K.)

  5. Study of 241 Am alpha spectra resolution using a ionization chamber with different grid types

    This paper describes some techniques used in the design of high resolution gridded ionization chambers for measurements of absolute activity of radionuclides. Details of the geometry of the system and its electrodes are presented; their shape and the spacing between the grid wire were studied. The experimental spectra obtained with an 241 Am source using 90% Ar and 10% C H4 as a flow gas show a total resolution of 39 KeV in very good agreement with best results available in the literature. (author). 17 refs., 2 figs., 3 tabs

  6. Electronic structure of polycrystalline Cd metal using {sup 241}Am radioisotope

    Dhaka, M. S., E-mail: msdhaka75@yahoo.co.in [Department of Physics, University College of Science, M. L. S. University, Udaipur-313001 (India); Sharma, G. [Department of Pure and Applied Physics, University of Kota, Kota-324005 (India); Mishra, M. C. [Department of Physics, R. R. M. Government College, Jhunjhunu-333001 (India); Sharma, B. K. [Department of Physics, University of Rajasthan, Jaipur-302004 (India)

    2014-04-24

    Electronic structure study of the polycrystalline cadmium metal is reported. The experimental measurement is undertaken on a polycrystalline sheet sample using 59.54 keV radioisotope of {sup 241}Am. These results are compared with the ab initio calculations. The theoretical calculations are performed using linear combination of atomic orbitals (LCAO) method employing the density functional theories (DFT) and Hartree-Fock (HF) and augmented plane wave (APW) methods. The spherically averaged APW and LCAO based theoretical Compton profiles are in good agreement with the experimental measurement however the APW based theoretical calculations show best agreement.

  7. Influence of organic fertilization on the sorption mechanisms of {sup 241} Am in tropical soils; A influencia da adubacao organica nos mecanismos de sorcao do {sup 241} Am em solos tropicais

    Pereira, Tatiane Rocha

    2009-07-01

    In this work the mechanisms involved in the sorption of {sup 241}Am were investigated depending on the physicochemical properties of some Brazilian soils and on alterations promoted by organic amendment. This experimental study was conducted in a controlled area, where pots containing different kinds of soils (histisol, ferralsol and nitisol), with different organic amendment doses (without amendment; 2 kg m{sup -2} and 4 kg m{sup -2}) were artificially contaminated by radioactive solution water, which contained {sup 241}Am. Migration studies, distribution (or partition) coefficient (KJ), bioavailability and organic matter were carried out in these soils, with ar without organic amendment. In order to evaluate the effective bioavailability of radionuclides, radish (Raphanus sativus L.) was cultivated in these pots, and later the concentration of {sup 241}Am in radish's roots was measured. The main results show that {sup 241}Am tends to be strongly attached to organic matter and that organic amendment in tropical soils minimizes the radionuclide studied desorption. Also, distribution (or partition) coefficient values for {sup 241}Am were generated and these values are smaller than those ones determined for soils from temperate zones. Physical and chemical fractioning of organic matter were carried out. (author)

  8. Removal of inhaled 241Am oxide of various particle sizes from beagle dogs by lung lavage and chelation treatment

    The removal of 241Am oxide aerosols of various particle sizes from the lung was studied in 24 Beagle dogs. There were four groups of dogs with six dogs per group and each group inhaled an aerosol of 241Am oxide of a different particle size or particle size distribution. The four aerosols had sizes of: 0.75 μm AD, sigma/sub g/ 1.1; 1.5 μm AD, sigma/sub g/ 1.1; 3.0 μm AD, sigma/sub g/ 1.1; or 1.5 μm AMAD and sigma/sub g/ of 1.6. Three of the dogs in each group were treated with 10 lung lavages, the first lavage performed 2 days after exposure and the last lavage on day 49 after exposure. Each of these treated dogs was also given 100 mg diethylenetriaminepentaacetic acid (DTPA) intravenously daily for 4 days after 241Am exposure and twice per week thereafter to the end of the study. Daily excreta collections were made on each of the dogs until sacrifice at 64 days after exposure. The sacrifice body burden (SBB) was much lower for all of the treated dogs compared to the untreated dogs. The 241Am activity found in the recovered lavage fluid was two to four times greater than the sacrifice body burden. These results suggest that the treatment procedures were effective in reducing the lung and body burden of 241Am

  9. Performance comparison of an 241Am-Be neutron source-based PGNAA setup with the KFUPM PGNAA setup

    Monte Carlo calculations have been carried out to compare the performance of an 241Am-Be neutron source-based prompt gamma neutron activation analysis (PGNAA) setup with that of the 2.8 MeV neutron-based PGNAA setup at King Fahd University of Petroleum and Minerals (KFUPM) to analyze Portland cement samples. This work is a part of a wide Monte Carlo studies being conducted at KFUPM in search of a more efficient neutron source for its 2.8 MeV neutrons, from the D(d,n) reaction, based PGNAA facility. In this study an 241Am-Be neutron source-based PGNAA setup was simulated. For comparison, the diameter of a cylindrical external moderator of the 241Am-Be neutron source, based PGNAA setup, was assumed to be similar to that used in the KFUPM PGNAA setup. It was revealed that although the optimum geometry of the 241Am-Be neutron source-based setup is similar to that of the KFUPM PGNAA facility, the performance of the 241Am-Be neutron source-based setup is slightly poorer than that of the 2.8 MeV neutron-based setup. (author)

  10. Incidence of liver tumors in beagles with body burdens of 239Pu or 241Am

    Tetravalent 239Pu or trivalent 241Am in a citrate buffer, given via a single intravenous injection to beagles, induced very pronounced liver changes, usually at relatively long postinjection times. The lesions consisted of cell injury or cell necrosis which was followed by nodular hyperplasia and a significant incidence of primary liver tumors. The most frequent neoplasm was the bile duct adenoma, followed by the bile duct carcinoma. A lesser number of sarcomas were also induced, especially fibrosarcomas. The number of hepatic cell tumors was low. An abnormally high incidence of both hyperplastic nodules and primary liver tumors occurred at long postinjection times and at average doses extending down to ∼10 rads. The various nodular lesions and liver tumors frequently occurred as incidental findings in dogs dying from other causes, especially bone cancer. In comparison to bone neoplasia, the liver was a much less important target organ in the high-dose level groups, but in some of the low-dose groups, especially in the 241Am groups, the risk of radiation-induced liver cancer was approximately equal to or exceeded the risk of skeletal tumors. However, in any projection of the risks observed in this animal model to man, one should be mindful that the beagle skeleton is approximately 25 times more sensitive to radiation-induced bone neoplasia than is the human skeleton (Mays et al., 1976) and that the radiosensitivity difference for the beagle and human liver is unknown. 41 refs., 8 figs., 5 tabs

  11. Determination of Pu isotopic composition and 241Am by high resolution gamma spectrometry on solid samples

    The present report gives a detailed account of the development of non-destructive assay technique using high resolution gamma-ray spectrometry (HRGS) for determination of plutonium (Pu) isotopic composition and the 241Am content in solid Pu samples. Energy range 120-420 keV was used in this study. The methodology involves in situ relative efficiency calibration during the measurement process itself, to reduce the errors and increase the reliability of the method. Twenty solid Pu samples of power reactor and research reactor grade were analyzed by this method and the results were compared with those obtained by thermal ionization mass spectrometry. The accuracy of the final results depends strongly upon the accuracy of the available nuclear data (decay constant, gamma abundance etc.). MATLAB based programme was written to perform the analysis. A counting time of 4 hour was chosen for achieving good statistics on the results for samples having 100-200 mg of Pu. The attainable accuracy is found to be 0.5-1% for the fissile isotopes (239Pu + 241Pu) and 5-10% for 241Am content. (author)

  12. Installation and measurement capacity of 3 x 592 GBq 241Am-Be neutron irradiation cell

    In this study, the installation and measurement capacity of the neutron irradiation system are investigated. First of all an irradiation geometry enabling optimum irradiation was designed for three 241Am-Be sources each of it having 592 GBq activity. Neutron irradiation system was installed after design and optimization of the system including the design of appropriate moderator and shielding were completed. Radiation safety standards of the Neutron Research Laboratory fulfilling the requirements of national regulation were achieved with unique configuration of the shielding materials. In this study the results of qualitative and quantitative detection limits obtained for Na, Al, Cl, K, Ti, V, Mn, Fe, Co, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Mo, Ru, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Yb, Lu, Hf, W, Pt, Au, Th and U elements by using the neutron irradiation cell comprising 3 x 592 GBq 241Am-Be isotopic neutron source are presented and discussed. (orig.)

  13. Orally administered DTPA penta-ethyl ester for the decorporation of inhaled (241)Am.

    Sueda, Katsuhiko; Sadgrove, Matthew P; Huckle, James E; Leed, Marina G D; Weber, Waylon M; Doyle-Eisele, Melanie; Guilmette, Raymond A; Jay, Michael

    2014-05-01

    Diethylenetriaminepentaacetic acid (DTPA) is an effective decorporation agent to facilitate the elimination of radionuclides from the body, but its permeability-limited oral bioavailability limits its utility in mass-casualty emergencies. To overcome this limitation, a prodrug strategy using the penta-ethyl ester form of DTPA is under investigation. Pharmacokinetic and biodistribution studies were conducted in rats by orally administering [(14) C]DTPA penta-ethyl ester, and this prodrug and its hydrolysis products were analyzed as a single entity. Compared with a previous reporting of intravenously administered DTPA, the oral administration of this prodrug resulted in a sustained plasma concentration profile with higher plasma exposure and lower clearance. An assessment of the urine composition revealed that the bioactivation was extensive but incomplete, with no detectable levels of the penta- or tetra-ester forms. Tissue distribution at 12 h was limited, with approximately 73% of the administered dose being associated with the gastrointestinal tract. In the efficacy study, rats were exposed to aerosols of (241) Am nitrate before receiving a single oral treatment of the prodrug. The urinary excretion of (241) Am was found to be 19% higher than with the control. Consistent with prior reports of DTPA, the prodrug was most effective when the treatment delays were minimized. PMID:24619514

  14. Measurement of thermal neutron cross section for {sup 241}Am(n,f) reaction

    Kobayashi, Katsuhei; Yamamoto, Shuji; Fujita, Yoshiaki [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Miyoshi, Mitsuharu; Kimura, Itsuro; Kanno, Ikuo; Shinohara, Nobuo

    1997-03-01

    Making use of a standard neutron spectrum field with a pure Maxwellian distribution, the thermal neutron cross section for the {sup 241}Am(n,f) reaction has been measured relative to the reference value of 586.2b for the {sup 235U}(n,f) reaction. For the present measurement, electrodeposited layers of {sup 241}Am and {sup 235}U have been employed as back-to-back type double fission chambers. The present result at neutron energy of 0.0253 eV is 3.15 {+-} 0.097b. The ENDF/B-VI data is in good agreement with the present value, while the JENDL-3.2 data is lower by 4.2%. The evaluated data in JEF-2.2 and by Mughabghab are higher by 0.9% and 1.6%, respectively than the present result. The ratios of the earlier experimental data to the present value are distributed between 0.89 and 1.02. (author)

  15. Evidence of radiolytic oxidation of 241Am in Na+/Cl-HCO3-/CO32- media

    This paper examines Americium behavior in Cl- media at room temperature in connection with environmental and waste disposal programs. Most published values on U, Np, Pu and Am complexation in chloride media have been determined using extraction methods. Spectrophotometric techniques are not sensitive enough to prove actinide complexation by chloride, which is confirmed in this paper for Am(III). Am(OH)3(s), AmOHCO3(s), Am2(CO3)3(s) or NaAm(CO3)2(s) solid phases can control the Am solubility, depending on the chemical conditions of the aqueous phase (usually PCO2). 241Am solubility is here found to be higher in NaCl 4M media than in NaCl 0.1 M (up to 3 orders of magnitude). Addition of a reducing agent (metallic iron) lowers the solubility. After a week, solubilities in NaCl 0.1 M and 4 M are similar. These results are consistent with Am(III) radiolytic oxidation to Am(V), due to α radiations. Little evidence of Cl- or mixed Cl--CO32- complexes is found in these conditions. In Na+-OH--Cl- media, 241Am(III) oxidation had also been proposed. Slow kinetics of precipitation could induce experimental uncertainties

  16. New data from the 243Am + 48Ca reaction give cross-bombardment verification of elements 113, 115 and 117

    The reaction 243Am + 48Ca has been reinvestigated to provide new evidence for the discovery of elements 113, 115. Twenty eight new 288115 decay chains were detected in this reaction to increase from three to 31 the number of 288115 atoms observed. In addition, four new decay chains were observed for the first time and assigned to the decay of 289115. These new 289115 events have the same properties for their decay chains as those observed for 289115 populated in the alpha decay of 293117 produced in the 249Bk + 48Ca reaction to provide cross-bombardment evidence. These new high statistics data sets and the cross-bombardment agreement provide definitive evidence for the discoveries of the new elements with Z = 113, 115, 117.

  17. Development of the MICROMEGAS Detector for Measuring the Energy Spectrum of Alpha Particles by using a 241-Am Source

    Kim, Do Yoon; Shin, Jae Won; Park, Tae-Sun; Hong, Seung-Woo; Andriamonje, Samuel; Kadi, Yacine; Tenreiro, Claudio

    2016-01-01

    We have developed MICROMEGAS (MICRO MEsh GASeous) detectors for detecting {\\alpha} particles emitted from an 241-Am standard source. The voltage applied to the ionization region of the detector is optimized for stable operation at room temperature and atmospheric pressure. The energy of {\\alpha} particles from the 241-Am source can be varied by changing the flight path of the {\\alpha} particle from the 241 Am source. The channel numbers of the experimentally-measured pulse peak positions for different energies of the {\\alpha} particles are associated with the energies deposited by the alpha particles in the ionization region of the detector as calculated by using GEANT4 simulations; thus, the energy calibration of the MICROMEGAS detector for {\\alpha} particles is done. For the energy calibration, the thickness of the ionization region is adjusted so that {\\alpha} particles may completely stop in the ionization region and their kinetic energies are fully deposited in the region. The efficiency of our MICROMEGA...

  18. The potential of coconut fibers in raw and treated forms to remove {sup 241}Am from aqueous solutions

    Fonseca, Heverton C.O.; Jesus, Nella N.M. de; Nobre, Vanessa B.; Potiens Junior, Ademar; Sakata, Solange K., E-mail: sksakata@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    In the Radioactive Waste Management (GRR) at the Nuclear and Energy Research Institute (IPEN/CNEN-SP) vegetal biomass has been studied as adsorbent to remove radioisotopes from radioactive liquid wastes as part of the radioactive waste treatment program. In this work coconuts fiber was evaluate as biosorbent to remove {sup 241}Am from aqueous solutions and many different parameters were studied such as particle size (35 and 80 mesh) and contact time (between 5 and 60 minutes). In order to evaluate if the treated biomass could remove more {sup 241}Am the experiments were also performed using raw biomass and treated with H{sub 2}O{sub 2} in basic conditions. When the experiment was carried out using raw coconuts fiber with 80 mesh, neutral conditions after 5 minutes of contact time 99% of the radionuclide was removed from the aqueous solution. This result shows the potential of this biomass to remove {sup 241}Am from radioactive liquid wastes. (author)

  19. The potential of coconut fibers in raw and treated forms to remove 241Am from aqueous solutions

    In the Radioactive Waste Management (GRR) at the Nuclear and Energy Research Institute (IPEN/CNEN-SP) vegetal biomass has been studied as adsorbent to remove radioisotopes from radioactive liquid wastes as part of the radioactive waste treatment program. In this work coconuts fiber was evaluate as biosorbent to remove 241Am from aqueous solutions and many different parameters were studied such as particle size (35 and 80 mesh) and contact time (between 5 and 60 minutes). In order to evaluate if the treated biomass could remove more 241Am the experiments were also performed using raw biomass and treated with H2O2 in basic conditions. When the experiment was carried out using raw coconuts fiber with 80 mesh, neutral conditions after 5 minutes of contact time 99% of the radionuclide was removed from the aqueous solution. This result shows the potential of this biomass to remove 241Am from radioactive liquid wastes. (author)

  20. Recoil-range studies of heavy products of multinucleon transfer from 18O to 245Cm and 249Cf

    Recoil range distributions were measured for alpha and spontaneous fission activities made in the bombardment of 245Cm and 249Cf with 18O from 6.20 MeV/nucleon down to the interaction barrier. The shape of the distributions indicates tht transfers of up to four protons take place via a combination of quasi-elastic (QET) and deep inelastic (DIT) mechanisms, rather than complete fusion-de-excitation (CF) or massive transfer (MT). Angular distributions constructed from recoil range distributions, assuming QET/DIT, indicate that the QET component contributes more significantly to the heavy product residue cross section than the DIT, even though primary cross sections are expected to be higher for DIT than for QET. This may be explained qualitatively as a result of the high excitation energies associated with DIT; the very negative Q/sub gg/ of projectile stripping for these systems combined with the lower expected optimal Q/sub rxn/ of QET compared to DIT can give QET products comparatively low excitation

  1. Synthesis of the isotopes of elements 118 and 116 in the 249Cf and 245Cm+48Ca fusion reactions

    Oganessian, Y T; Utyonkov, V K; Lobanov, Y V; Abdullin, F S; Polyakov, A N; Sagaidak, R N; Shirokovsky, I V; Tsyganov, Y S; Voinov, A A; Gulbekian, G G; Bogomolov, S L; Gikal, B N; Mezentsev, A N; Iliev, S; Subbotin, V G; Sukhov, A M; Subotic, K; Zagrebaev, V I; Vostokin, G K; Itkis, M G; Moody, K J; . Patin, J B; Shaughnessy, D A; Stoyer, M A; Stoyer, N J; Wilk, P A; Kenneally, J M; Landrum, J H; Wild, J F; Lougheed, R W

    2006-01-31

    The decay properties of {sup 290}116 and {sup 291}116, and the dependence of their production cross sections on the excitation energies of the compound nucleus, {sup 293}116, have been measured in the {sup 245}Cm({sup 48}Ca,xn){sup 293-x}116 reaction. These isotopes of element 116 are the decay daughters of element 118 isotopes, which are produced via the {sup 249}Cf+{sup 48}Ca reaction. They performed the element 118 experiment at two projectile energies, corresponding to {sup 297}118 compound nucleus excitation energies of E* = 29.2 {+-} 2.5 and 34.4 {+-} 2.3 MeV. During an irradiation with a total beam dose of 4.1 x 10{sup 19} {sup 48}Ca projectiles, three similar decay chains consisting of two or three consecutive {alpha} decays and terminated by a spontaneous fission (SF) with high total kinetic energy of about 230 MeV were observed. The three decay chains originated from the even-even isotope {sup 294}118 (E{sub {alpha}} = 11.65 {+-} 0.06 MeV, T{sub {alpha}} = 0.89{sub -0.31}{sup +1.07} ms) produced in the 3n-evaporation channel of the {sup 249}Cf+{sup 48}Ca reaction with a maximum cross section of 0.5{sub -0.3}{sup +1.6} pb.

  2. In vitro dose-response of macrophages to 239PuO2 and 241AmO2

    As part of a study designed to examine various means of solubilizing actinide particles within macrophages, we have measured the in vitro effects of 241AmO2 and 239PuO2 on these cells. Dose distribution within the cell population was estimated by autoradiography and compared to cell detachment as a function of time. The 241AmO2 and 239PuO2 were toxic in proportion to their radioactivity rather than their mass. Approximately 385 intracellular disintegrations are required from either radionuclide to cause cells to detach from the flask surface

  3. Transfer of 241Am and 237Pu from euphausiid moults to a carbonate-rich marine sediment

    Concentrations of 241Am and 237Pu adsorbed onto moulted exoskeletons from the euphausiid Meganyctiphanes norvegica decreased exponentially with 50% retention times of 3-7 d when moults were incubated in filtered seawater with small amounts of carbonate-rich sediment. Over 95% of sediment weight was present as -2) was greatest in the medium-fine sand fraction which had the highest carbonate content. These particles constituted -2 surface: atoms μm-3 in solution) was 103-104 times higher than similar quotients for 241Am and 237Pu sorbed to surfaces of organic particles are transferred to sediments. (author)

  4. Actinides separation and long-lived fission products from the high activity effluent

    The aim of this document is to study the decontamination of a high activity effluent in minor actinides-α transmitters (241Am, 243Am, 243Cm, 245Cm, 237Np, 238Pu, 242Pu, 235U, 238U) and long-life fissions products (133Cs, 137Cs) and then the separation of Am, Cm, Np, Cs and Pu, U traces. (TEC). 16 figs., 1 tab

  5. Characterization of the neutron field of the 241AmBe in a calibration room

    The field of neutrons produced by an isotopic source of neutrons of 241 Am Be had been characterized. The characterization was carried out modeling those relevant details of the calibration room and simulating the neutron transport at different distances of the source. The calculated spectra were used to determine the equivalent environmental dose rate. A series of experiments were carried out with the Bonner sphere spectrometric system to measure the spectra in the same points where the calculations were carried out and with these spectra the rates of environmental dose were calculated. By means of a one sphere dosemeter type Berthold the rates of environmental dose were measured. To the one to compare the calculated spectra and measured its were found small differences in the group of the thermal neutrons due to the elementary composition used during the simulation. When comparing the derived rates starting from the calculated spectra with those measured it was found a maxim difference smaller to 13%. (Author)

  6. Attenuation studies near K-absorption edges using Compton scattered 241Am gamma rays

    K K Abdullah; N Ramachandran; K Karunakaran Nair; B R S Babu; Antony Josephm; Rajive Thomas; K M Varier

    2008-04-01

    We have carried out photon attenuation measurements at several energies in the range from 49.38 keV to 57.96 keV around the K-absorption edges of the rare earth elements Sm, Eu, Gd, Tb, Dy and Er using 59.54 keV gamma rays from 241Am source after Compton scattering from an aluminium target. Pellets of oxides of the rare earth elements were chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. The scattered gamma rays were detected by an HPGe detector. The results are consistent with theoretical values derived from the XCOM package.

  7. Improvement of evaluated neutron nuclear data for 237Np and 241Am

    The nuclear data of 237Np and 241Am that are particularly important among the minor actinides were investigated by comparing JENDL-3.2 with the recent evaluated data and available experimental data. As a result of the study, several defects of JENDL-3.2 data were revealed. They were improved on the basis of experimental data or recent evaluated data. For the both nuclides, main quantities revised in the present work were the resonance parameters, cross sections, angular and energy distributions of secondary neutrons, number of neutrons per fission. The data were given in the neutron energy range from 10-5 eV to 20 MeV, and compiled in the ENDF-6 format. (author)

  8. In situ determination of 241Am on Enewetak Atoll. Date of survey: July 1977-December 1979

    An in situ gamma ray spectrometer system was operated at Enewetak Atoll from July 1977 to December 1979 in support of the Enewetak Cleanup Project. The system employed a high purity germanium planar detector suspended at a height of 7.4 m above ground. Conversion factors were established to relate measured photopeak count rate data to source concentration in the soil. Data obtained for 241Am, together with plutonium-to-americium ratios obtained from soil sample analyses, were used to establish area-averaged surface (0 to 3 cm) transuranic concentration values. In areas which exceeded cleanup criteria, measurements were made in an iterative fashion to guide soil removal until levels were reduced below the cleanup criteria. Final measurements made after soil removal had been completed were used to document remaining surface transuranic concentration values and to establish external exposure rate levels due to 137Cs and 60Co

  9. A comparative study of the carcinogenetic effects of 241Am, 239Pu and 237Np

    In this experiment, 420 wistar rats were used to study the comparative carcinogenetic effects of 241Am, 239Pu and 237Np. These nuclides were injected to animals intravenously, subcutaneously or directly into the lung (Stansen's lung puncture method) in doses of 1.0, 5.0 and 8.5 μCi/kg, respectively. As soluble nitrate, the nuclides were rapidly transfered from the site of injection into the bone and the liver. Osteosarcomas were found in some animals 8 months to one year after intoxication. Diagnosis of osteosarcoma is based on the histopatological examination and X-ray photography. In the Am-poisoned rats the incidence of osteosarcoma is about 31-74%, varied with different doses and different routes of intoxication; in Pu-poisoned rats, the incidence of osteosarcoma is about 55-66%. while in Np-poisoned rats, it is about 36-53%. Primary lung cancers were also found in those animals poisoned by means of Stansen's lung puncture method with the above three nuclides. The incidence of primary lung cancers is about 6% in Am-and Pu-poisoned rats and 13% in Np-poisoned rats. The incidence of metastasis of osteosarcoma in lung is about 25-65% for Am-poisoned rats, 45-55% for Pu-poisoned rats and 41-80% for Np-poisoned rats. The life-span of above poisoned rats was significantly shorter than that of the normal control animals. The chemical weight for 241Am, 239Pu and 237Np in same unit of radioactivity (1.0 μCi) equals to 0.308 μg, 15.9 μg and 1418.7 μg, respectively. For this reason, we have to pay more attention to the chemical mass effect in carcinogenesis of the above three nuclides

  10. Characterization of 241Am and Pu content in soil from peaceful nuclear explosions regions by γ/X-spectrometric method

    The γ/X-spectrometric methodology and apparatus for analysis of the 241Am content in the soil and plant samples from the peaceful nuclear explosions areas in Yakutiya and the Perm region are briefly presented. The conclusion is made on the possibility of applying the γ/X-spectrometric methodology for the wide-scale measurements in the peaceful nuclear explosions regions

  11. Bone marrow from Balb/c mice radiocontaminated with 241Am in utero shows a deficient in vitro haemopoiesis

    Radiation damage from 241Am to bone marrow cells was manifest in long-term bone marrow cultures (LTC) from offspring of mice radiocontaminated at 14th day of gestation (119, 479, 803, 1754 kBq 241Am kg). Offspring were reared by their own contaminated mother for 3 weeks postnatal. LTC from these offspring were less able to support in vitro CFC proliferation than control LTC. This radiation damage persisted 71 weeks after radiocontamination in utero. Damage was observed at lower doses if 241Am contamination occurred at foetal rather than adult ages. Radiation damage was observed only using LTC. After culturing LTC in 25% FCS and recharging the stromal adherent layer with bone marrow cell suspensions originating either from control offspring or from offspring contaminated with 241Am in utero evidence was found that the proliferation capacity of haemopoietic cells was diminished. However, the nature of effects on the stromal elements is currently somewhat equivocal. Following in utero contamination stromal adherent cells appeared to support better production of in vitro CFC. (author)

  12. Characterization of the neutron field from the 241Am-Be isotopic source of the IPHC irradiator

    A measurement campaign has been carried out recently to provide the source intensity and the reference spectra around a neutron irradiation facility based on 241Am-Be radionuclide source, using the UAB Bonner Sphere Spectrometer. This facility, which consists of a bunker, a container/shielding for the source and an irradiation device that uses an automated remote-controlled system for the source positioning and rotating during the dosimeter irradiation, is intended to be routinely used to check the response of passive dosimeters, namely those based on photo-stimulated imaging plates and solid-state nuclear track detectors. The measurement results, in terms of neutron spectra and global dosimetric quantities (i.e., fluence and ambient dose equivalent rates) at different distances with respect to the 241Am-Be source, were compared with Monte Carlo simulations using the MCNPX code and a good agreement was observed. An estimation of the un-scattered neutron spectrum directly emitted from the 241Am-Be source is given as well. - Highlights: ► We describe a neutron irradiation facility based on 241Am-Be radioactive source. ► The neutron field was characterized with a Bonner sphere spectrometer (BSS). ► Monte Carlo simulations using the MCNPX code were in good agreement with BSS. ► The un-scattered neutron spectrum is provided and compared to that given by the ISO-8529 standard. ► The neutron intensity of the 241Am-Be source is also estimated

  13. Characterization of 241Am and 134Cs bioaccumulation in the king scallop Pecten maximus: investigation via three exposure pathways

    In order to understand the bioaccumulation of 241Am and 134Cs in scallops living in sediments, the uptake and depuration kinetics of these two elements were investigated in the king scallop Pecten maximus exposed via seawater, food, or sediment under laboratory conditions. Generally, 241Am accumulation was higher and its retention was stronger than 134Cs. This was especially obvious when considering whole animals exposed through seawater with whole-body concentration factors (CF7d) of 62 vs. 1, absorption efficiencies (A0l) of 78 vs. 45 for seawater and biological half-lives (Tb1/2l) of 892 d vs. 22 d for 241Am and 134Cs, respectively. In contrast, following a single feeding with radiolabelled phytoplankton, the assimilation efficiency (AE) and Tb1/2l of 134Cs were higher than those of 241Am (AE: 28% vs. 20%; Tb1/2l: 14 d vs. 9 d). Among scallop tissues, the shells always contained the higher proportion of the total body burden of 241Am whatever the exposure pathway. In contrast, the whole soft parts presented the major fraction of whole-body burden of 134Cs, which was generally associated with muscular tissues. Our results showed that the two radionuclides have contrasting behaviors in scallops, in relation to their physico-chemical properties. - Highlights: → We determined Am and Cs uptake and depuration kinetics following seawater, food and sediment exposures. → We determined radionuclide tissue distribution after exposure and after depuration periods. → Am was mainly associated to the shell whatever the exposure pathway was. → Transfer processes occurred between soft and hard tissues for Am.

  14. Determination of 51Cr and 241Am X-ray and gamma-ray emission probabilities per decay

    Full text: In this paper results of X-ray and gamma-ray emission probabilities per decay of 51Cr and 241Am are presented. The measurements were carried out by means of an HPGe planar spectrometer. The radionuclide 51Cr decays with a half-life of 27.7 days by electron capture process populating the excited levels of 51V, which emits X-rays between 4 and 6 keV and a gamma ray of 320 keV. The radionuclide 241Am decays with a half-life of 157,850 days by alpha emission, populating the excited levels of 237Np, which emits X-rays between 11 and 20 keV and two main gamma rays of 26 and 59 keV. The choice of 51Cr was made due to the need of more results since there are two discrepant sets of values for the 320 keV emission probability per decay in the literature. The choice of 241Am was made because, although this radionuclide be considered a primary standard for spectrometers calibration using its well-known 59 keV gamma ray emission probability, the 26 keV gamma ray and the X-rays emission probabilities present large discrepancies in the literature. The activity of 51Cr and 241Am samples was determined in a 4-coincidence counting system. The same sources were measured in an HPGe planar spectrometer with Be window, suitable for measurements in low energy range. The HPGe spectrometer was calibrated in a well defined geometry by means of 54Mn, 55Fe, 57Co, 133Ba, 152Eu, 166mHo and 241Am (59 keV) sources, previously standardized in a coincidence system. The MCNP Monte Carlo code was used for simulation of the spectrometer calibration curve for the selected geometry, and compared with the experimental one

  15. 241Am distribution and retention in pregnant mice, in their offspring and in non-pregnant mice: comparison between continuous Am administration and single injection

    Pregnant BALB/c mice and age and sex matched nulliparous controls were contaminated with 241Am (13 kBq per mouse). Five days after the termination of contamination, 241Am incorporation was measured in the tissues of adults and in the liver an the femur of newborn and one-month-old mice. Pregnancy resulted in higher 241Am concentrations in bone but lower concentrations in the liver of the mothers. Protracted administration of 241Am compared to a single injection resulted in a lower concentration of 241Am in the livers of pregnant mice, their nulliparous controls and from newborn mice. The higher 241Am concentration in the femur at birth after protected exposure before 14 days of gestation compared to protracted exposure after 14 days of gestation could reflect the increased placental transfer of 241Am with advancing gestational age. Radiation doses to the femur were estimated between 4 and 20 mGy. Haemopoietic changes were noticed at these dose levels in all groups until at least 6 months after birth. (author)

  16. A Monte Carlo-based knee phantom for in vivo measurements of 241Am in bone

    Determination of internal contamination of 241Am can be done by direct counting of gamma emission using a Whole Body Counter. Due to the strong attenuation of the low-energy photons, it is advised to perform the measurement on bones surrounded by a thin layer of tissue. In vivo measurements are performed at CIEMAT using a system of four Low-Energy germanium (LE Ge) detectors calibrated with realistic anthropomorphic phantoms. As an alternative, Monte Carlo techniques are applied on voxel phantoms based on tomographic images to avoid the need of different physical phantoms for different radionuclides and organs. This technique is employed to study the convenience of americium measurements in the knee for the evaluation of the deposition in the whole skeleton. The spatial distribution of the photon fluence through a cylinder along the axis of the leg has been calculated to determine the best counting geometry. The detection efficiency is then calculated and the results are compared with those obtained using the physical phantom to validate the proposed method

  17. An electrostatic potential meter based on 241Am α-ray ionic current measurement

    An electrostatic potential meter on the basis of α-ray ionic current measurement was experimentally investigated, especially to have high position resolving power at the measurement. A rod-shaped probe of the potential meter, following a picoammeter, was topped with a thin cylindrical ion collector where a small 241Am α-ray source of 0.93 MBq was mounted. The α-rays are emitted towards a charged material to be examined, and ionize air in a restricted region near the collector head. A movable shade electrode was also attached to the probe so as to surround the ion collector to extend and adjust measurable potential range. To design the probe of the potential meter, potential distribution inside the shade electrode was precisely examined in advance by the finite element method with a computer calculation. The sensitivity of the potential meter is adjusted by changing slightly the position of the shade electrode, since the electric field strength of the ionized region is strongly affected by the electrode position. The experiments employing charged plates of comb-shape showed that the potential meter with the shade electrode of 25 mm outside diameter has a resolving power of about 30 mm and is applicable for measuring potential up to 7 kV with relative error less than 5 %. (author)

  18. Distribution of 239Pu and 241Am in the human skeleton

    The 241Am and 239Pu distribution in the skeletons of two former nuclear workers has been measured. The skeletons of both individuals appear to be within normal limits for Caucasian men about 50 y old. Both had lower limb bones that were heavier than the age controls and Case I had upper-body bones that were lighter than the age control group. The distribution of americium in the skeleton of Case I, 25 years post exposure, indicated that a more rapid turnover of initially deposited americium on the bone surfaces of cancellous bone, as compared to that deposited on the bone surfaces of compact bone, had occurred. This resulted in a larger proportion of americium located in the compact bone of the extremities and a lesser quantity in the more cancellous bones of the vertebral column, pelvis and rib cage. A similar shift in the distribution of plutonium occurred in Case II in the 35 y since initial deposition, but at a slower rate than that for americium. The ratio of each actinide in the liver to that in the systemic system (liver content/systemic system content) was 0.065 and 0.436, for americium and plutonium, respectively, suggesting that a much more rapid turnover of americium in the liver, compared to plutonium, provided a much larger fraction of that nuclide for circulatory feedback to the remodeling skeletal system. 8 references, 3 tables

  19. Artificial (Pu 90Sr, 241Am) and natural (U) isotopes in human bones from Poland

    In two papers we have presented results if analyses of artificial isotopes (238,239,240Pu, 241Am and 90Sr) content in human bones, using samples collected during hip joint replacement surgery. Since the patients were members of general population (not exposed in any particular form to artificial radionuclides) results can be treated as current background level for Poland and perhaps also whole central Europe. During this project the open question appeared - what is the level in human bones of natural alpha emitters like 238U-, 234U, for instance. Therefore about 30 human hip joint bone samples are being now analysed for the presence of uranium along with mentioned above artificial radionuclides. Samples are ashen and sequential radiochemical analyse is applied for separation of Pu, Sr and Am isotopes followed by separation of uranium using anion exchange resin. Measurements of plutonium, americium and uranium are performed using alpha spectrometry. That for 90Sr is done by LSC. Results will be presented during conference. Document available in abstract form only. (authors)

  20. Collimator duct for neutron radiographs using a source of 241Am-Be

    With the aim of designing a collimator system to realize Neutron Radiographs using source of 241Am-Be, a collimator was designed using two removable modules. One parameter of merit to be considered in the building of a collimator is the intensity of the neutron beam on the image plane. Therefore, the choice of the inner coating material is of utmost importance. As the scattered neutrons can reduce the resolution of the neutron radiographic image, it would be opportune to capture them so that the neutron beam is aligned. Thus, an aligning module made of an absorbent material was designed, to coat the wall end extensions of the collimator. Two other parameters are essential to configure a collimator system: the length, L, and diameter of the opening, D. Geometric resolution of the neutron radiographic image is defined by the ratio L/D, as well as the neutron flux on the image plane. Simulations with code MCNP-4B were conducted to select the geometry of the collimator, the materials for the structure and coating and the dimensions for the L and D parameters and aluminum was chosen as the structural material and cadmium for coating. (author)

  1. Solubilization of 241AmO2 in alveolar macrophage cultures

    Cultured rabbit alveolar macrophages were used to study the effect of phagocytosis on the solubilization of 241AmO2. A comparison was made of the solubility of phagocytized AmO2 and AmO2 in cell-free media, in the presence and absence of 0.1 mM DTPA. A time-dependent increase of 26% in the soluble (0.1-μm filtrate) intracellular americium fraction was seen in macrophages cultured for 3 days. The addition of 0.1mM DTPA to culture medium resulted in an increase of 36% over the same time period. In contrast, cell-free media without DTPA resulted in less than a 2% increase in solubility after 4 days of incubation, while addition of 0.1mM DTPA resulted in a 5% increase over the same time period. These results indicate cell-mediated solbuilization of phagocytized AmO2 by macrophages

  2. Neutron transmission and capture cross section measurements for 241Am at the GELINA facility

    Resonance parameters for neutron-induced reactions on 241Am below 110 eV have been determined. The parameters result from a resonance shape analysis of transmission and capture data measured at the time-of-flight facility GELINA, with the accelerator operating at a 50 Hz repetition rate. The transmission experiments were carried out at a 25 m station using a Li glass scintillator. The capture experiments were performed at a 12.5 m station by applying the total energy detection principle in combination with the pulse height weighting technique using a pair of C6D6 detectors. The normalization of the capture data was determined by a combined least squares adjustment of the transmission and capture data. From the adjusted resonance parameters a capture cross section of 749 ± 35 b for a neutron energy of 0.0253 eV and an average radiation width of Γγ = 42.0 meV for s-wave resonances were obtained. A missing-level analysis for s-wave neutron resonances within the statistical model results in compatible values with previous estimates. The neutron widths obtained in this work are approximately 22% larger compared to other experimental data and evaluated data libraries. Also the thermal capture cross section is larger than most of the recommended values. However, the resonance parameter file presented in this work is consistent with results of both integral experiments and of the experimentally determined resonance integrals. (authors)

  3. Measurement of neutron induced fission of {sup 235}U, {sup 233}U and {sup 245}Cm with the FIC detector at the CERN n-TOF facility

    Calviani, M.; Karadimos, D.; 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.; Cano-Ott, D.; Capote, R.; Carrapic, 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.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Jericha, E.; Kappeler, F.; Kadi, Y.; 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

    A series of measurements of neutron induced fission cross section of various transuranic isotopes have been performed at the CERN n-TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n-TOF neutron flux, the well known cross section of the {sup 235}U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as {sup 235}U, {sup 233}U and {sup 245}Cm in the energy range from 0.050 eV to about 2 MeV. These results for {sup 235}U, {sup 233}U and {sup 245}Cm show results consistent with databases in the resonance region, with no normalization required for {sup 233}U. In the case of {sup 245}Cm, for the energy range between thermal and 20 eV, we obtained the first experimental data ever published, while showing a good agreement with previous data in the region above that value.

  4. Measurement of neutron induced fission of 235U, 233U and 245Cm with the FIC detector at the CERN n-TOF facility

    A series of measurements of neutron induced fission cross section of various transuranic isotopes have been performed at the CERN n-TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n-TOF neutron flux, the well known cross section of the 235U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as 235U, 233U and 245Cm in the energy range from 0.050 eV to about 2 MeV. These results for 235U, 233U and 245Cm show results consistent with databases in the resonance region, with no normalization required for 233U. In the case of 245Cm, for the energy range between thermal and 20 eV, we obtained the first experimental data ever published, while showing a good agreement with previous data in the region above that value.

  5. Excretion of DTPA from human body and the effect of DTPA on the excretion of 241Am in urine

    The excretion of DTPA in urine was studied after intramuscular injection or inhalation as an aerosol. For two administration of DTPA, the excretion fraction of DTPA in urine can be described by sum of two exponent functions. For intramuscular injection, the fast removal part is about 97% of all the activity administered with a half-life of 88 minutes; the slow removal part is about 3% with a half-life of 292 minutes; the excretion rate of DTPA within 24 hours is about 99%. For inhalation of DTPA, the fast removal part is about 81% with a half-life of 92 minutes; the slow removal part is about 19% with a half-life of 624 minutes. The therapeutic effect of DTPA on 241Am is good, the average excretion of 241Am in urine after treatment is 18 times more than that before treatment

  6. Preparation and measurement of 241Am solutions to establish traceability of counting equipment to the National Physical Laboratory

    Measurement of the 241Am activity in ampoules prepared from a stock solution has established direct traceability of the Harwell low geometry counters numbers 12 and 13 to the 4π alpha/gamma coincidence counting equipment at the National Physical Laboratory. The mean values obtained from measurements on three ampoules at each establishment agree to within 0.2%; the difference lies within the respective experimental errors. (author)

  7. New source moderator geometry to improve performance of 252Cf and 241Am Be source-based PGNAA setups

    Naqvi, A. A.; Abdelmonem, M. S.; Al-Misned, Ghada; Al-Ghamdi, Hanan

    2006-06-01

    The gamma ray yield from a 252Cf and a 241Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the 252Cf and the 241Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a 252Cf and a 241Am-Be source-based PGNAA setups.

  8. Study of neutron moderation using the {sup 241}Am-Be spectrum with hydrogenated materials; Estudo da moderacao de neutrons utilizando o espectro de {sup 241}Am-Be com materiais hidrogenados

    Santos, A.R.L.; Silva, F.S.; Martins, M.M.; Pereira, W.W., E-mail: aleiras@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ/LNMRI/LN), Rio de Janeiro, RJ (Brazil). Lab. de Neutrons; Freitas, B.M. [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Tavares, D.Y.S. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    This work intends to assess materials for moderation of neutrons, trying to reduce the rate of H{sub p}(10) and H⁎p(10), reducing the effective dose of Occupationally Exposed Workers (OEW) who handle this source daily. The neutron spectra moderated by different materials was performed with a neutron source of {sup 241}Am-Be in an electronic positioning system, using a neutron spectrometry with Bonner Sphere at 50 cm from the center of source. The materials used for moderation were paraffin, silicone and Polyvinyl Chloride (PVC) resin ball. (author)

  9. Measurement of the neutron-induced fission cross-section of 243Am relative to 235U from 0.5 to 20 MeV

    The ratio of the neutron-induced fission cross-sections of 243Am and 235U was measured in the energy range from 0.5 to 20 MeV with uncertainties of ∼ 4%. The experiment was performed at the CERN nTOF facility using a fast ionization chamber. With the good counting statistics that could be achieved thanks to the high instantaneous flux and the low backgrounds, the present results are useful for resolving discrepancies in previous data sets and are important for future reactors with improved fuel burn-up. (orig.)

  10. Measurement of the neutron-induced fission cross-section of {sup 243}Am relative to {sup 235}U from 0.5 to 20 MeV

    Belloni, F.; Milazzo, P.M.; Abbondanno, U.; Fujii, K.; Moreau, C. [Istituto Nazionale di Fisica Nucleare, Trieste (Italy); Calviani, M. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); CERN, Geneva (Switzerland); Colonna, N.; Barbagallo, M.; Marrone, S.; Meaze, M.H.; Tagliente, G.; Terlizzi, R. [Istituto Nazionale di Fisica Nucleare, Bari (Italy); Mastinu, P.; Gramegna, F. [Lab. Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A. [Irfu, CEA, Gif-sur-Yvette (France); Alvarez, H.; Cano-Ott, D.; Duran, I.; Embid-Segura, M.; Gonzalez-Romero, E.; Paradela, C.; Tarrio, D. [Univ. de Santiago de Compostela, Galicia (Spain); Alvarez-Velarde, F.; Guerrero, C.; Martinez, T.; Villamarin, D.; Vincente, M.C. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andrzejewski, J.; Marganiec, J. [Univ. of Lodz (Poland); Audouin, L.; Dillmann, I.; Heil, M.; Kaeppeler, F.; Mosconi, M.; Plag, R.; Voss, F.; Walter, S.; Wisshak, K. [Karlsruhe Inst. of Technology, Eggenstein-Leopoldshafen (Germany). Inst. fuer Kernphysik; Badurek, G.; Jericha, E.; Leeb, H.; Oberhummer, H. [Technische Univ. Wien, Atominstitut der Oesterreichischen Universitaeten, Wien (Austria); Baumann, P.; David, S.; Kerveno, M.; Lukic, S.; Rudolf, G. [IReS, Centre National de la Recherche Scientifique/IN2P3, Strasbourg (France); Becvar, F.; Krticka, M. [Charles Univ., Faculty of Mathematics and Physics, Prague (Czech Republic); Calvino, F.; Cortes, G.; Poch, A.; Pretel, C. [Univ. Politecnica de Catalunya, Barcelona (Spain); Capote, R. [NAPC/Nuclear Data Section, International Atomic Energy Agency, Vienna (Austria); Univ. de Sevilla (Spain); Carrapico, C.; Goncalves, I.; Salgado, J.; Santos, C.; Tavora, L.; Vaz, P. [Inst. Tecnologico e Nuclear, Lisbon (Portugal)] [and others

    2011-12-15

    The ratio of the neutron-induced fission cross-sections of {sup 243}Am and {sup 235}U was measured in the energy range from 0.5 to 20 MeV with uncertainties of {approx} 4%. The experiment was performed at the CERN n{sub T}OF facility using a fast ionization chamber. With the good counting statistics that could be achieved thanks to the high instantaneous flux and the low backgrounds, the present results are useful for resolving discrepancies in previous data sets and are important for future reactors with improved fuel burn-up. (orig.)

  11. Neutron-induced fission cross sections of 233U and 243Am in the energy range 0.5 Mev En 20 MeV @ n_TOF

    Belloni, F; Milazzo, P M; Calviani, M; Colonna, N; Mastinu, P; Abbondanno, U; Aerts, G; Álvarez, H; Álvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Baumann, P; Becvár, F; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P; Chepel, V; Chiaveri, E; 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; González-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Jericha, E; Käppeler, 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; Martínez, T; Massimi, C; Mengoni, A; 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; Vazl, P; Ventura, A; Villamarin, D; Vincente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wiescher, M; Wisshak, K

    2011-01-01

    Neutron-induced fission cross-sections of actinides have been recently measured at the neutron time of flight facility n_TOF at CERN in the frame of a research project involving isotopes relevant for nuclear astrophysics and nuclear technologies. Fission fragments are detected by a gas counter with good discrimination between nuclear fission products and background events. Neutron-induced fission cross-sections of 233U and 243Am were determined relative to 235U. The present paper reports the results obtained at neutron energies between 0.5 and 20 MeV.

  12. Updated estimates of 239240Pu + 241Am inventory, spatial pattern, and soil tonnage for removal at Nuclear Site-201, NTS

    Updated estimates of 239240Pu + 241Am inventory and spatial pattern in surface soil are given for Nuclear Site (NS)-201 in Area 18 of the Nevada Test Site (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 239240Pu to 241Am ratio of 7.5 used by Simpson and Gilbert (1980) to obtain previous results. Estimated concentration contours, 68% confidence bands for the contours and estimated median concentrations for 50 x 50 ft blocks are given. The total Pu + Am inventory estimated to be in the top 5 cm of soil over the 109 hectare study (an area 5.2 hectares larger than used by Simpson and Gilbert, 1980) is approximately 16.3 curies. The approximate 68% confidence interval on this inventory estimate is about 6.7 to 45.6 curies. 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. These new estimates of inventory and spatial patterns are within the range of sampling error of previous estimates obtained by Simpson and Gilbert

  13. Nuclear data measurements in 3x592 GBq 241Am-Be neutron cell

    The aim of this study is to present the results of the activities carried out within the scope of the Nuclear Data Measurements in 3x592 GBq Am-Be Neutron Cell project. The study covers the establishment of neutron irradiation systems, neutron and gamma dose rate evaluations in and around the laboratory, performance measurements of neutron irradiation systems, measurements of thermal, epithermal and fast neutron flux, gamma spectrometer efficiency calibrations, fast neutron fission product yield measurements for fertile nuclides (232Th and 238U), cross section measurements for fast neutron threshold detectors, gamma ray intensity measurements of the nuclides in uranium decay chain, elemental detection limit measurements and the half life measurement of short-lived isotopes. First of all, an irradiation geometry, which enables optimum irradiation, was designed for an irradiation system of 3 241Am-Be sources with 592 GBq activity each. Paraffin was chosen in order to slow down the source neutrons. An equilateral quadrangle with 70 cm side length and 60 cm height was used as paraffin moderator. Experimentally, it was determined that paraffin with approximately 3.5 cm thickness slows down to maximum thermal neutron flux of 241Am-Be neutrons. Paraffin block was placed on the base of the source room. In order to determine the positions of thermal and fast neutron irradiations, indium wires were irradiated with 5 mm intervals vertically parallel to the neutron sources in thermal and fast neutron irradiation cells. The position of maximum thermal and fast neutron fluxes is 61.5 cm for the thermal neutron irradiation cells and 69 cm for the fast neutron irradiation cell, from the top of the irradiation pipes down. One of the most important parameters of nuclear data measurements is the counting efficiency of the gamma spectrometer used for each counting geometry. For this reason, the detector efficiencies for the related counting geometries need to be measured accurately

  14. Thermal neutron capture cross-section measurements of 243Am and 242Pu using the new mini-INCA α- and γ-spectroscopy station

    In the framework of the Mini-INCA project, dedicated to the study of Minor Actinide transmutation process in high neutron fluxes, an α- and γ-spectroscopy station has been developed and installed at the High Flux Reactor of the Laue-Langevin Institut. This set-up allows short irradiations as well as long irradiations in a high quasi-thermal neutron flux and post-irradiation spectroscopy analysis. It is well suited to measure precisely, in reference to 59Co cross-section, neutron capture cross-sections, for all the actinides, in the thermal energy region. The first measurements using this set-up were done on 243Am and 242Pu isotopes. Cross-section values, at En=0.025eV, were found to be (81.8+/-3.6)b for 243Am and (22.5+/-1.1)b for 242Pu. These values differ from evaluated data libraries by a factor of 9% and 17%, respectively, but are compatible with the most recent measurements, validating by the way the experimental apparatus

  15. Alpha and conversion electron spectroscopy of 238,239Pu and 241Am and alpha-conversion electron coincidence measurements

    Dion, Michael P.; Miller, Brian W.; Warren, Glen A.

    2016-09-01

    A technique to determine the isotopic constituents of a mixed actinide sample has been proposed by a coincident alpha-conversion electron measurement. This presents a unique signature to allow the unfolding of isotopes that possess overlapping alpha particle energy and reduce backgrounds of an unseparated sample. The work presented here are results of conversion electron spectroscopy of 241Am, 238Pu and 239Pu using a dual-stage peltier-cooled 25 mm2 silicon drift detector and alpha spectroscopy with a passivated ion implanted planar silicon detector. The conversion electron spectra were evaluated from 20-55 keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information and calibration to aid in the coincident measurement approach. Furthermore, an alpha-conversion electron spectrometer was assembled using the silicon based detectors described and results of a coincident spectrum analysis is reported for 241Am.

  16. Measurement and analysis of the $^{241}$Am(n,$\\gamma$) cross section at the CERN n_TOF facility.

    Fraval, Kevin

    In the context of the current nuclear technology, the radiotoxicity of the spent fuel of a typical PWR reactor is dominated by minor actinides for times greater than 104 years. In particular, 241Am and its 432 years half-life is responsible for about half of the minor actinide content of a PWR spent fuel. This thesis work consisted in measuring and analysing the 241Am(n, ) cross section at the CERN n TOF facility. After selecting exclusively the events obtained with lead shielding in front of the C6D6 detectors, the amplitude-energy calibration has to be adjusted with time, by using a photon coming from the 27Al(,,p)30Si reaction. Histogram extraction included applying a weighting function (obtained by MCNP simulation), a dead time correction, and a normalization to the compound nucleus excitation energy. The background corrected spectra were normalized relatively to the 4.9 eV resonance on 197Au. Finally, the resonance analysis was performed using the SAMMY code. The extracted thermal value is 678±68 barns,...

  17. Measurement of mass yields from the 241Am(2nth,f reaction at the Lohengrin Spectrometer

    Köster U.

    2013-03-01

    Full Text Available The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. While the yields are known for the major actinides (235U, 239Pu in the thermal neutron-induced fission, only few measurements have been performed on 242Am. The interest of 242Am concerns the reduction of radiotoxicity of 241Am in nuclear wastes using transmutation reactions. This paper presents the measurement of the fission mass yields from the reaction 241Am(2nth,f performed at the Lohengrin mass spectrometer (ILL, France for both the light and the heavy peaks: a total of 41 mass yields have been measured. The experiment was also meant to determine whether there is a difference in mass yields between the isomeric state and the ground state as it exists in fission and capture cross sections. The method used to address this question is based on a repeated measurement of a set of fission mass yields as a function of the ratio between the 242gAm and the 242mAm fission rates. The presented experiment is also a first step towards the measurement of the isotopic fission yields of 242Am.

  18. Production of monodisperse respirable aerosols of 241AmO2 and evaluation of in vitro dissolution

    A method is described for production of monodisperse (sigma//sub g/ less than 1.2) particles of 241AmO2 for use in inhalation experiments with dogs and rodents. The effects of physical and chemical factors on the production of polydisperse aerosols of 241AmO2 were studied and evaluated. The best aerosol was achieved when a suspension of americium hydroxide with 2.5 mg Am/ml at pH = 7.3 was aerosolized and passed through two heating columns in succession, the first at 3000C and the second at 10500C. The particles were roughly spherical and had densities near 8 gm/cm3; the aerosol AMAD and sigma/sub g/ were about 1.5 μm and 1.7, respectively. Monodisperse particles were separated and collected with the Lovelace Aerosol Particle Separator (LAPS) and subsequently suspended in deionized water with pH adjusted to 10.2 with NH3 for nebulization to produce monodisperse aerosols for inhalation exposures. Particles collected on filters during inhalation experiments were used for evaluation of in vitro dissolution rates with two systems and various forms of a lung fluid simulant. The important role of phosphate ions in such dissolution systems was demonstrated, suggesting the potential for the equally important role of free phosphate in retarding dissolution of AmO2 particles in the lung. (U.S.)

  19. Measurement and analysis of the 241Am(n,γ) cross section at the CERN nTOF facility

    In the context of the current nuclear technology, the radiotoxicity of the spent fuel of a typical PWR reactor is dominated by minor actinides for times greater than 104 years. In particular, 241Am and its 432 years half-life is responsible for about half of the minor actinide content of a PWR spent fuel. This thesis work consisted in measuring and analysing the 241Am(n,γ) cross section at the CERN nTOF facility. After selecting exclusively the events obtained with lead shielding in front of the C6D6 detectors, the amplitude-energy calibration has to be adjusted with time, by using a photon coming from the 27Al(α,p)30Si* reaction. Histogram extraction included applying a weighting function (obtained by MCNP simulation), a dead time correction, and a normalization to the compound nucleus excitation energy. The background corrected spectra were normalized relatively to the 4.9 eV resonance on 197Au. Finally, the resonance analysis was performed using the SAMMY code. The extracted thermal value is 678±68 barns, the uncertainty being mostly due to the large background level. The resolved range was extended from 150 eV to 320 eV, with a total of 192 resonances that had to be added of heavily modified. The unresolved region was analysed up to 150 keV, yielding a larger average cross section than previously evaluated below 20 keV. (author)

  20. Obtaining the mass attenuation coefficient of the wood to a beam of gamma-ray of 241Am

    Full text: The quality of wood produced in Brazil reforestation has been the subject of many discussions in the Forestry Sector. SeEKXing to produce a rapid growth and wood quality, the Forestry Sector, found in Applied Nuclear Physics, a precise method of determining the density of wood known as ad hoc technique of attenuation of gamma-ray. The radioisotope used in this technique is that it has a picture 241Am peak of 59.6 keV gamma-ray. This work has the objective of determining the mass attenuation coefficient of wood of the genus Eucalyptus for 241Am radioisotope. We used 324 samples of wood from six different treatments: a seminal of Eucalyptus grandis; two clones of E. grandis; three clones of the hybrid E. grandis x E. urophylla. The same assay was used for the six treatments. It was determined the basic density of the samples by the method of immersion in water and then the basic density was converted into apparent density in the moisture equilibrium and it was determined the attenuation coefficient of mass. Preliminary results showed that the attenuation coefficient of mass did not vary between treatments, and its average value 0.1822 ± 0.0015. It was to here that the attenuation coefficient of mass in the wood of the genus Eucalyptus in moisture equilibrium can be constant. (author)

  1. New search for correlated e{sup +}e{sup -} pairs in the {alpha} decay of {sup 241}Am

    Bernabei, R.; Belli, P.; Di Marco, A. [INFN, Sezione Roma ' ' Tor Vergata' ' , Rome (Italy); Universita di Roma ' ' Tor Vergata' ' , Dipartimento di Fisica, Rome (Italy); Cappella, F.; D' Angelo, A.; Incicchitti, A. [INFN, Sezione Roma, Rome (Italy); Universita di Roma ' ' La Sapienza' ' , Dipartimento di Fisica, Rome (Italy); Caracciolo, V.; Castellano, S.; Cerulli, R.; Laubenstein, M. [Laboratori Nazionali del Gran Sasso, INFN, Assergi (Italy); Dai, C.J.; He, H.L.; Ma, X.H.; Sheng, X.D.; Wang, R.G. [Chinese Academy, IHEP, Beijing (China); Montecchia, F. [INFN, Sezione Roma ' ' Tor Vergata' ' , Rome (Italy); Universita di Roma ' ' Tor Vergata' ' , Dipartimento di Ingegneria Civile e Ingegneria Informatica, Rome (Italy); Tretyak, V.I. [Institute for Nuclear Research, Kyiv (Ukraine); Ye, Z.P. [Chinese Academy, IHEP, Beijing (China); University of Jing Gangshan, Jiangxi (China)

    2013-05-15

    A new search for production of correlated e{sup +}e{sup -} pairs in the {alpha} decay of {sup 241}Am has been carried out deep underground at the Gran Sasso National Laboratory of the INFN by using pairs of NaI(Tl) detectors of the DAMA/LIBRA set-up. The experimental data show an excess of double coincidences of events with energy around 511keV in faced pairs of detectors, which are not explained by known side reactions. This measured excess gives a relative activity {lambda} = (4.70{+-}0.63) x 10{sup -9} for the Internal Pair Production (IPP) with respect to the alpha decay of {sup 241}Am; this value is of the same order of magnitude as previous determinations. In a conservative approach the upper limit {lambda} < 5.5 x 10{sup -9} (90% C.L.) can be derived. It is worth noting that this is the first result on IPP obtained in an underground experiment, and that the {lambda} value obtained in the present work is independent of the live-time estimate. (orig.)

  2. Measurement of Neutron Induced Fission of 235U, 233U and 245Cm with the FIC Detector at the CERN n()TOF Facility

    A series of measurements of neutron induced fission cross section of various TRU isotopes have been performed at the CERN n()TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n()TOF neutron flux, the well known cross section of the 235U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as 235U, 233U and 245Cm in the energy range from 0.050 eV to about 2 MeV.

  3. Energy distributions and yields of 3H, 4He and 6He-particles emitted in the 245Cm(n_th,f) reaction

    Serot, O; Wagemans, J; Goeminne, G; Köster, U; Geltenbort, P; Nesvizhevsky, V V

    2001-01-01

    The energy distributions and yields of light charged particles emitted during thermal neutron induced fission of 245Cm have been measured at the high flux reactor of the Institute Laue Langevin in Grenoble (France). The detection of the ternary particles was done using a Delta-E/E telescope, permitting a good separation of the ternary particles. In this way, the characteristics of the energy distribution (average energy and full width at half maximum) for 4He, 3H and 6He particles as well as their emission probabilities could be determined. For the emission probabilities per fission, the following values were obtained: LRA/B=(2.15+-0.05)E-3, 3H/B=(1.85+-0.10)E-4 and 6He/B=(4.95+-1.25)E-5.

  4. 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

  5. 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)

  6. Characterization of the neutron field of the {sup 241}AmBe in a calibration room; Caracterizacion del campo de neutrones del {sup 241} AmBe en una sala para calibracion

    Vega C, H.R. [UAZ, A.P. 336, 98000 Zacatecas (Mexico); Gallego, E.; Lorente, A. [Universidad Politecnica de Madrid, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain)] e-mail: rvega@cantera.reduaz.mx

    2003-07-01

    The field of neutrons produced by an isotopic source of neutrons of {sup 241} Am Be had been characterized. The characterization was carried out modeling those relevant details of the calibration room and simulating the neutron transport at different distances of the source. The calculated spectra were used to determine the equivalent environmental dose rate. A series of experiments were carried out with the Bonner sphere spectrometric system to measure the spectra in the same points where the calculations were carried out and with these spectra the rates of environmental dose were calculated. By means of a one sphere dosemeter type Berthold the rates of environmental dose were measured. To the one to compare the calculated spectra and measured its were found small differences in the group of the thermal neutrons due to the elementary composition used during the simulation. When comparing the derived rates starting from the calculated spectra with those measured it was found a maxim difference smaller to 13%. (Author)

  7. Evaluation of committed effective doses from internal contamination of 241Am using experimentally determined parameters of the contaminant

    Internal contamination of workers with 241Am has occurred a few times since the beginning of the 1970's, mainly in the workplace where radionuclide sources were produced, and later on, also during liquidation of radioactive waste. Contamination in workers was measured in vivo and bioassay was performed. Solubility of aerosol in lungs was studied by in vitro dissolution test with a simulant solution of the extracellular airway lining fluids. Model calculation for the estimation of intakes was done with the experimentally obtained parameters of aerosol, with modified times of intake, with scattering factors, including Types A and B errors, and with corrections on skull size for in vivo measurements. For most cases, an acceptable fit to the experimental data was obtained; for two cases with intakes taking place long time ago (∼30 y), some changes in the model are necessary. (authors)

  8. Evaluation of committed effective doses from internal contamination of {sup 241}Am using experimentally determined parameters of the contaminant

    Malatova, I.; Beckova, V.; Vrba, T. [National Radiation Protection Institute, Srobarova 48, 100 00 Prague 10 (Czech Republic)

    2007-07-01

    Internal contamination of workers with {sup 241}Am has occurred a few times since the beginning of the 1970's, mainly in the workplace where radionuclide sources were produced, and later on, also during liquidation of radioactive waste. Contamination in workers was measured in vivo and bioassay was performed. Solubility of aerosol in lungs was studied by in vitro dissolution test with a simulant solution of the extracellular airway lining fluids. Model calculation for the estimation of intakes was done with the experimentally obtained parameters of aerosol, with modified times of intake, with scattering factors, including Types A and B errors, and with corrections on skull size for in vivo measurements. For most cases, an acceptable fit to the experimental data was obtained; for two cases with intakes taking place long time ago ({approx}30 y), some changes in the model are necessary. (authors)

  9. In situ determination of /sup 241/Am on Enewetak Atoll. Date of survey: July 1977-December 1979

    Tipton, W.J.; Fritzsche, A.E.; Jaffe, R.J.; Villaire, A.E.

    1981-11-01

    An in situ gamma ray spectrometer system was operated at Enewetak Atoll from July 1977 to December 1979 in support of the Enewetak Cleanup Project. The system employed a high purity germanium planar detector suspended at a height of 7.4 m above ground. Conversion factors were established to relate measured photopeak count rate data to source concentration in the soil. Data obtained for /sup 241/Am, together with plutonium-to-americium ratios obtained from soil sample analyses, were used to establish area-averaged surface (0 to 3 cm) transuranic concentration values. In areas which exceeded cleanup criteria, measurements were made in an iterative fashion to guide soil removal until levels were reduced below the cleanup criteria. Final measurements made after soil removal had been completed were used to document remaining surface transuranic concentration values and to establish external exposure rate levels due to /sup 137/Cs and /sup 60/Co.

  10. Monte Carlo optimization of sample dimensions of an 241Am Be source-based PGNAA setup for water rejects analysis

    Idiri, Z.; Mazrou, H.; Beddek, S.; Amokrane, A.; Azbouche, A.

    2007-07-01

    The present paper describes the optimization of sample dimensions of a 241Am-Be neutron source-based Prompt gamma neutron activation analysis (PGNAA) setup devoted for in situ environmental water rejects analysis. The optimal dimensions have been achieved following extensive Monte Carlo neutron flux calculations using MCNP5 computer code. A validation process has been performed for the proposed preliminary setup with measurements of thermal neutron flux by activation technique of indium foils, bare and with cadmium covered sheet. Sensitive calculations were subsequently performed to simulate real conditions of in situ analysis by determining thermal neutron flux perturbations in samples according to chlorine and organic matter concentrations changes. The desired optimal sample dimensions were finally achieved once established constraints regarding neutron damage to semi-conductor gamma detector, pulse pile-up, dead time and radiation hazards were fully met.

  11. Determination of boron in water solution by an indirect neutron activation technique from a 241Am/Be source

    Boron content in water solutions has been analysed by Indirect Activation Technique a twin 241Am/Be neutron source with a source strength of 9x106 n/seg. The boron concentration was inferred from the measurement of the activity induced in a vanadium flux monitor. The vanadium rod was located inside the boron solution in a standart geometrical set up with respect to the neutron source. Boron concentrations in the range of 100 to 1000 ppm were determined with an overall accuracy of about 2% during a total analysis time of about 20 minutes. Eventhough the analysis is not selective for boron yet due the rapid, simple and precise nature, it is proposed for the analysis of boron in the primary coolant circuit of Nuclear Power Plants of PWR type. (Author)

  12. Use of a lowest intensity 241Am Compton spectrometer for the measurement of directional Compton profiles of ZnSe

    In this paper we report on electron momentum densities in ZnSe using Compton scattering technique. For the directional measurements we have employed a newly developed 100 mCi 241Am Compton spectrometer which is based on a small disc source with shortest geometry. For the theoretical calculations we have employed a self-consistent Hartree-Fock linear combination of atomic orbitals (HF-LCAO) approach. It is seen that the anisotropy in the measured Compton profiles is well reproduced by our HF-LCAO calculation and the other available pseudopotential data. The anisotropy in the Compton profiles is explained in terms of energy bands and bond length. - PACS numbers: 13.60.Fz, 78.70. Ck, 78.70.-g (orig.)

  13. Similarity of 241Am and 59Fe speciation in selected freshwaters and of their adsorption on crayfish exoskeleton

    The particulate fraction and the organically complexed fraction of freshly added 241Am and 59Fe were determined in 21 prefiltered surface waters. The adsorptive behaviour of both radionuclides on a biological surface (isolated carapace segments of crayfish) was tested simultaneously. A striking similarity was observed in the chemical and absorptive behaviours of both radionuclides. The stoichiometry of particulate formation revealed a 3/4, Am to Fe ratio. This same stoichiometric relationship was observed in organic complexation, while adsorptive behaviour was characterised by a 1/1, Am to Fe ratio. It is concluded that Am predictably follows the chemistry of freshly added Fe at least over a 15 day period. This observation may find interesting application in risk assessment where use can be made of the well-known geochemical cycling of iron to predict the behaviour of man-made Am. (author)

  14. Microdosimetric evaluation of relative biological effectiveness for 103PD, 125I, 241AM, and 192IR brachytherapy sources

    Purpose: To determine the microdosimetric-derived relative biological effectiveness (RBE) of 103Pd, 125I, 241Am, and 192Ir brachytherapy sources at low doses and/or low dose rates. Methods and Materials: The Theory of Dual Radiation Action can be used to predict expected RBE values based on the spatial distribution of energy deposition at microscopic levels from these sources. Single-event lineal energy spectra for these isotopes have been obtained both experimentally and theoretically. A grid-defined wall-less proportional counter was used to measure the lineal energy distributions. Unlike conventional Rossi proportional counters, the counter used in these measurements has a conducting nylon fiber as the central collecting anode and has no metal parts. Thus, the Z-dependence of the photoelectric effect is eliminated as a source of measurement error. Single-event spectra for these brachytherapy sources have been also calculated by: (a) the Monte Carlo code MCNP to generate the electron slowing down spectrum, (b) transport of monoenergetic electron tracks, event by event, with our Monte Carlo code DELTA, (c) using the concept of associated volume to obtain the lineal energy distribution f(y) for each monoenergetic electron, and (d) obtaining the composite lineal energy spectrum for a given brachytherapy source based on the electron spectrum calculated at step (a). Results: Relative to 60Co, the RBE values obtained from this study are: 2.3 for 103Pd, 2.1 for 125I, 2.1 for 241Am, and 1.3 for 192Ir. Conclusions: These values are consistent with available data from in vitro cell survival experiments. We suggest that, at least for these brachytherapy sources, microdosimetry may be used as a credible alternative to time-consuming (and often uncertain) radiobiological experiments to obtain information on radition quality and make reliable predictions of RBE in low dose rate brachytherapy

  15. 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).

  16. The biokinetics of four 239Pu/241Am dioxide bearing dusts in the rat after inhalation: the implications for occupational exposure

    The aims of the work described here were to provide an experimental basis for evaluating the committed effective dose equivalent per unit intake together with the ALI for four industrial oxide bearing dusts, and to assess the extent to which 241Am could be used for estimating the 239Pu content of the lung after an accidental intake of these materials. (author)

  17. Artificial radionuclides 90Sr and 241Am in the sediments of the Baltic Sea: Total and spatial inventories and some temporal trends

    Highlights: • The inventories of 137Sr and 241Am in the Baltic Sea is studied. • About 20 sediment cores around the Baltic Sea were analyzed. • The results show that 90Sr distribution is uneven and effected by the Chernobyl fallout. • 241Am is more evenly distributed in the sediments. • The Baltic Sea is the most contaminated sea with respect to 137Cs in sediments. -- Abstract: The Baltic Sea was contaminated by radioactivity following global nuclear fallout and later by the Chernobyl accident. Despite the decrease of radioactivity caused by radioactive decay, radionuclides have a prolonged residence time in the water of the Baltic Sea due to slow water exchange and relatively rapid sedimentation. Very little is known about the amounts or spatial differences of 90Sr and 241Am in the Baltic Sea sediments. In this study, 20 sediment cores taken around the Baltic Sea were investigated to estimate inventories of these radionuclides. The rough results show that the Chernobyl fallout added the amount of 90Sr in the same areas where the increase of 137Cs can be detected, whereas this is not the case for 241Am which is more evenly distributed in the sea bottom. In addition, local differences occur in the concentrations. These results are an important amendment to the radioactivity baseline of the Baltic Sea

  18. 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

  19. Recoil-range studies of heavy products of multinucleon transfer from /sup 18/O to /sup 245/Cm and /sup 249/Cf

    McFarland, R.M.

    1982-09-01

    Recoil range distributions were measured for alpha and spontaneous fission activities made in the bombardment of /sup 245/Cm and /sup 249/Cf with /sup 18/O from 6.20 MeV/nucleon down to the interaction barrier. The shape of the distributions indicates tht transfers of up to four protons take place via a combination of quasi-elastic (QET) and deep inelastic (DIT) mechanisms, rather than complete fusion-de-excitation (CF) or massive transfer (MT). Angular distributions constructed from recoil range distributions, assuming QET/DIT, indicate that the QET component contributes more significantly to the heavy product residue cross section than the DIT, even though primary cross sections are expected to be higher for DIT than for QET. This may be explained qualitatively as a result of the high excitation energies associated with DIT; the very negative Q/sub gg/ of projectile stripping for these systems combined with the lower expected optimal Q/sub rxn/ of QET compared to DIT can give QET products comparatively low excitation.

  20. Implementation of a anti-coincidence system of 4{pi}NaI(Tl)-Cl and primary standardization of {sup 57}Co, {sup 124}Sb and {sup 241}Am; Implementacao de um sistema de anti-coincidencia 4{pi}NaI(Tl)-Cl e padronizacao primaria do {sup 57}Co, {sup 124}Sb e {sup 241}Am

    Silva, Carlos Jose da; Iwahara, Akira; Poledna, Roberto; Oliveira, Estela Maria de; Prinzio, Maria Antonieta de, E-mail: carlos@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Lopes, Ricardo Tadeu [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LIN/COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

    2009-07-01

    The Radionuclide Metrology Laboratory of the IRD-Brazil, implemented a primary standardization system which utilizes the anti-coincidence technique with live time keeping. For testing the performance of these system it was made the standardization of the {sup 57}Co, {sup 124}Sb and {sup 241}Am. Encourages results were obtained not only the standardization of {sup 241}Am but also of the {sup 124}Sb whose reference value obtained by the LNMRI was utilized for the key comparison organized by the IAEA and EURAMET. The standard uncertainties were of 0.28%, 0.22% and 0.13% for the {sup 57}Co, {sup 124}Sb and {sup 241}Am, respectively

  1. Parameter uncertainty analysis in the task of internal dose reconstruction based on 241Am organ activity measurements

    Retrospective individual dose assessment of workers chronically exposed to plutonium is an important task in investigation of possible health effects from internal plutonium depositions. In most cases inhalation is the primary mode of the plutonium exposures, though an additional route of plutonium intake through wounds (pinpricks) also occurs in some cases. Estimating of systemic and total body deposition of plutonium from urinalysis is usually used to carry out the task of individual dose assessment. But this technique used alone gives no information about the routes of intake and solubility of aerosol particles, which could result in wrong lung dose calculations. Direct in vivo measurements of 241Am content in lungs, skeleton and liver by whole-body counting technique allow one to improve the estimation of the organ deposition of plutonium and the estimation of the individual lung doses. Our method of plutonium dose calculating uses the fact that plutonium of reactor origin is accompanied by 241Am that is grown in from decay of the 241Pu parent. The algorithm applies the new ICRP Publication 66/67 models and takes into account such parameters as 241Pu/239Pu ratio, the activity ratio of 239Pu to the sum of alpha emitting plutonium isotopes, effective aging time of mixed fission products and actinides, particle size distribution of plutonium aerosols (AMAD) and a rate of intake within the period of employment. The purpose of this paper is to quantify the reliability of the model's prediction and retrospective dose calculations by the parameter uncertainty analysis. It takes into account the uncertainty of all parameters describing the components of the plutonium aerosol, AMAD and the rate of intake. The parameter uncertainty analysis involved assigning probability distributions to each parameter and the use of Monte Carlo simulation technique to produce a quantitative statement of confidence in the model's prediction. It is shown that cumulative distribution

  2. Prompt gamma-ray neutron activation analysis (PGNAA) system by using a 740 GBq 241Am-Be neutron source

    A PGNAA system consisting of a 740 GBq 241Am-Be neutron source and a gamma spectrometer with a n-type Ge (REGe) detector was installed at Ankara Nuclear Training and Research Center to measure the prompt gamma-rays produced by the interactions of thermal neutrons in the samples for the analysis of light elements such as B, P, S and Cl, and some trace elements with large cross sections (Cd, Hg, Sm, Gd, etc.). In the irradiation system, a 55 cm diameter cylinder tank filled with the water moderator comprises the neutron source placed in a polypropylene tube that was positioned in lead rings (internal diameter - 9 cm and outer diameter - 21 cm) in order to reduce the gamma rays emitted from the source such as 0.0596 MeV (241Am) and 4.43 MeV (0.6 gamma per neutron) from the 9Be(α, n) reaction in the source. The moderator tank was shielded with paraffin in all sides against fast neutrons. The thickness of paraffin at the front side of the tank is 28 cm and 18 cm at other sides. The neutron irradiation system was also shielded by using chevron lead bricks of 18 cm thickness. The background-prominent gamma-rays which is especially the 2.223 MeV gamma ray from the 1H(n, γ) reaction formed in hydrogenous materials used for neutron moderation was reduced remarkably in view of the permissible gamma dose for overall irradiation room. The neutrons thermalized in moderator travel through the hole with 6 cm diameter for the sample irradiation. The detector was shielded with Li2CO3 powder against thermal neutrons to avoid radiation damage and surrounded by additional lead bricks to reduce gamma-background. The measurements are carried out for efficiency calibration of the detector by using the standard source. The characteristics of PGNAA system with the isotopic neutron source and its analysis capability are discussed

  3. 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

  4. 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

  5. Experimental study of the neutron induced fission cross-section of 234U, 237Np and 243Am with time-of-flight spectrometry technics

    The current work concentrates on the measurements of the nuclear data needed for solving the problem of transmutation of radiotoxic waste. It includes fission cross-section of 234U in the energy range from thermal to 1 MeV, 237Np and 243Am in the resonance region and average group capture cross-section of 234U and 236U. Almost all of these data are recommended by IAEA as a first priority needs for transmutation problem. Another objective is to obtain the high resolution data of the fission cross-section of the 234U on the fission barrier to confirm the existence of the fine structure, attributed to the vibrational resonances in the third well of the fission barrier. The Dissertation summarizes more, than 10 years of the experiments, performed on the pulsed neutron sources IBR-2 and IBR-30 of Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research (FLNP JINR) in Dubna, Russia; 'Fakel' of Russian Scientific Center 'Kurchatov's Institute' and n-TOF of CERN. The TOF technique was used for neutron energy spectrometry and various kinds of detectors to mark the fission events. The independent measurements of the same isotopes done on different neutron sources and sometimes with different techniques gives strong, self-consistent set of data. (author)

  6. Determining the neutron spectrum of 241Am-Be and 252Cf sources using bonner sphere spectrometer

    M.A Varshabi

    2016-06-01

    Full Text Available Bonner spheres system is one of the ways of measuring neutron energy distribution which is often applied in spectrometry and neutron dosimetry. This system includes a thermal neutron detector, being located in the center of several polyethylene spheres, and it is still workable due to the isotropic response of the system which in turn is derived from the spherical symmetry of moderators and the broad measurable range of the energy. In order to practically use this spectrometer, it is necessary to calibrate this system using standard neutron sources. This research aimed to determine the calibration factor of Bonner spheres spectrometry system and energy spectrum of two standard 241Am-Be and 252Cf sources in the atomic energy organization. Calibration and experimental measurement were done via the two standard sources. The response vector of each detector was derived by using MCNPX simulation code, based on the Monte Carlo method. The spectra unfolding of this system was performed through iterative method using the SPUNIT code done in software NSDUAZ6LiI and BUMS. 

  7. Evidence for age-related performance degradation of 241Am foil sources commonly used in UK schools

    The characteristics of alpha radiation have for decades been demonstrated in UK schools using small sealed 241Am sources. There is a small but steady number of schools who report a considerable reduction in the alpha count rate detected by an end-window GM detector compared with when the source was new. This cannot be explained by incorrect apparatus or set-up, foil surface contamination, or degradation of the GM detector. The University of Liverpool and CLEAPSS collaborated to research the cause of this performance degradation. The aim was to find what was causing the performance degradation and the ramifications for both the useful and safe service life of the sources. The research shows that these foil sources have greater energy straggling with a corresponding reduction in spectral peak energy. A likely cause for this increase in straggling is a significant diffusion of the metals over time. There was no evidence to suggest the foils have become unsafe, but precautionary checks should be made on old sources. (paper)

  8. Recoiled Proton Track Registration in Polycarbonate Plastic by Irradiation of Neutron from 241Am-Be Radioisotope Source

    Full text: This research attempts to investigate properties of recoiled proton track registration in polycarbonate (PC) which was irradiated by neutrons from 241Am-Be source. The irradiated PC was etched with PEW solution (15% KOH, 45% H2O and 40% ethyl alcohol) at 70oC for 1 h. The recoiled proton tracks were observed under an optical microscope at approximately 100 times of magnification. The tracks were then characterized by using the Image J program which is an image processing and analysis software. The study showed that the average track density in PC was 2.74 x 105 tracks per square centimeter for a neutron flux of approximately 1.58 x 104neutrons/cm2.s at 2 weeks of irradiation time. The minimum and maximum track areas were found to be 3.443 and 340.698 μm2 while the minimum and maximum track diameters were found to be 4.137 and 20.828μm respectively

  9. Aluminium and copper analysis in metallic alloys by neutron activation analysis from an 241 Am-Be source

    Aluminium and copper have been determined in aluminium alloys by the method of activation with neutrons from an 241 Am-Be source of intensity 9,8 x 106 n/s. The activity induced due to reactions 27 Al (n, γ)28 Al and 63 Cu (n, γ)64 Cu have been measured with a NaI (Tl) detector coupled to a single channel system. In order to obtain the samples and standards of about the same composition, the material to be irradiated was powdered. In view of low intensity of neutron source it was necessary to use samples of up to 50 g. A series of preliminary irradiations were carried out to ensure that the geometry for the irradiation and for the counting are reproducible. The results have been compared with those obtained by chemical methods. Assuming that the results obtained by chemical method is exact, a maximum relative error of 3,6% is obtained by this method. The method has a good reproducibility. The time needed for analysis of aluminium and copper are 18 min and 2 hours 40 minutes respectively. Four different samples were analysed. The average of five measurements for one of the samples was: 88.0% for aluminium and 10.0% for copper. The standard deviation and coefficient of variation were 0,8 and 1.0% for aluminium and 0,2 and 2.0% for copper. (author)

  10. Application of the technique of attenuation of the gamma radiation of the 241Am in vegetable substratum

    The substratum animal, vegetable, mineral or artificial exercises the function of the soil, supplying to the plant sustain, nutritious, water and oxygen. The constant extraction of the fern-acu (xaxim), it has been taking to the presence in the official list of the threatened Brazilian species of extinction in reason of this intense destined commercial exploration the floriculture and gardening. For this reason the cut is being prohibited in several law of the Brazilian. As attempt of substitution of the exploration of the plant fiber fiber, a new substratum is being marketed at the market, it is the coxim, industrialized product of the coconut fiber (Cocus nucifera). Produced in the Northeast, where the culture of the coconut tree is extensive, the coconut fiber is a natural vegetable material abundant, renewable and very light resulting from the industrial processing of the peels of the coconut. Therefore, considering the substratum as important variable of the productive cycle of plants free from the soil, and for this responsible for the development and growth of the plants, it was had as objective in the present study, to determine density gradients in vegetable substratum of xaxim and coconut fiber in different humidity conditions, for the method of radiation gamma of the 241Am, seeking your application in the production of roses. (author)

  11. Measurement of fission yields from the 241Am(2nth,f reaction at the Lohengrin Spectrometer

    Amouroux Ch.

    2013-12-01

    Full Text Available The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. While the yields are known for the major actinides (235U, 239Pu in the thermal neutron-induced fission, only few measurements have been performed on 242Am. This paper presents the results of a measurement at the Lohengrin mass spectrometer (ILL, France on the reaction 241Am(2nth,f: a total of 41 mass yields in the light and the heavy peaks have been measured and compared with the fission process simulation code GEF. Modus operandi and first results of a second experiment performed in May 2013 on the same reaction but with the goal of extracting the isotopic yields are presented as well: 8 mass yields were re-measured and 18 isotopic yields have been investigated and are being analyzed. Results concerning the kinetic energy and its comparison with the GEF Code are also presented in this paper.

  12. Artificial (Pu {sup 90}Sr, {sup 241}Am) and natural (U) isotopes in human bones from Poland

    Mietelski, J.W.; Tomankiewicz, E. [Institute of Nuclear Phyics (Poland); Golec, E.; Golec, J.; Nowak, S.; Szczygiel, E. [The 5th Military Clinical Hospital and Polyclinic (Poland); Kuzma, K. [General Hospital (Poland)

    2014-07-01

    In two papers we have presented results if analyses of artificial isotopes ({sup 238,239,240}Pu, {sup 241}Am and {sup 90}Sr) content in human bones, using samples collected during hip joint replacement surgery. Since the patients were members of general population (not exposed in any particular form to artificial radionuclides) results can be treated as current background level for Poland and perhaps also whole central Europe. During this project the open question appeared - what is the level in human bones of natural alpha emitters like {sup 238}U-, {sup 234}U, for instance. Therefore about 30 human hip joint bone samples are being now analysed for the presence of uranium along with mentioned above artificial radionuclides. Samples are ashen and sequential radiochemical analyse is applied for separation of Pu, Sr and Am isotopes followed by separation of uranium using anion exchange resin. Measurements of plutonium, americium and uranium are performed using alpha spectrometry. That for {sup 90}Sr is done by LSC. Results will be presented during conference. Document available in abstract form only. (authors)

  13. 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.

  14. Characterization of the CRNA Bonner sphere spectrometer based on {sup 6}LiI scintillator exposed to an {sup 241}Am-Be neutron source

    Mazrou, Hakim [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz Fanon, B.P. 399, 16000 Alger (Algeria)], E-mail: mazrou_h@comena-dz.org; Sidahmed, Tassadit; Idiri, Zahir; Lounis-Mokrani, Zohra; Bedek, Said [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz Fanon, B.P. 399, 16000 Alger (Algeria); Allab, Malika [Faculte de Physique, Universite des Sciences et de la Technologie Houari-Boumediene (USTHB), Alger (Algeria)

    2008-02-15

    In the present work, measurements have been performed using an available multisphere neutron spectrometer based on a calibrated {sup 6}LiI scintillation detector (10mmox2mm) exposed to an {sup 241}Am-Be neutron source. Sensitive analysis has been performed to assess influence of angle and source-detector distances dependence on the detector responses. Our experimental responses were compared with the published experimental and calculated data for two {sup 241}Am-Be (ISO, PTB) neutron spectra with (4mmox4mm) {sup 6}LiI detector. A discrepancy by a factor of about two was achieved and it is chiefly due to the difference shown in active surface of both detectors.

  15. Evaluation of quantitative factors of 90Sr, 137Cs, 239Pu, 241Am transfer from contaminated soil with gastric and intestine juices of cows

    The biological availability and parameters of transuranium elements metabolism in an organism of cows pasturing in the Chernobyl NPP alienation zone are evaluated. The values of the radioactivity of 90Sr, 137Cs, 239Pu and 241Am are presented in samples of gastric and intestine juices of cows as well as in simulative solutions after soil processing by them. Quantitative parameters of 90Sr, 137Cs, 239Pu and 241Am transfer from solid phase of soil to gastric, intestine juice of cows as well as to simulative solutions have been estimated on the basis of results of laboratory incubation experiments. A prevailing role of enzyme complex and microflora of gastrointestinal tract in radionuclides transfer from solid phase of soil to solution has been shown

  16. NAA of copper in its ores by ''2''4''1Am-Be neutron source using the standard addition technique

    Neutron activation analysis using nuclear reactors as sources of activating particles is a well established technique, which has been described adequately in the literature and has been used for the analysis of a wide range of materials. The ''2''4''1Am-Be neutron source is also a useful source of activating particles for, although the neutron flux is relatively low (approximately 10''5 ncm''-''2 s''-''1) it is adequate for a range of analyses where extreme sensitivity is not of prime importance and offers the advantages of relatively low cost and ease of operation. The determination of Cu in its ores has been investigated for a typical industrial application of ''2''4''1Am-Be neutron activation by method of standard addition

  17. 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)

  18. The subcellular distribution of 239Pu, 241Am and 59Fe in the liver of rat and Chinese hamster as dependent on time

    The subcellular distribution of monomeric 239Pu, 241Am and iron in rat and Chinese hamster liver has been investigated by sucrose-, metrizamide- and Percoll-density gradients. In rat liver, the transuranium elements become and remain bound to typical lysosomes primary storage organelle in Chinese hamster liver. However, their apparent density in sucrose decreases with time, which possible indicates transition into telolysomes. The transuranium nuclides show a subcellular distribution which is quite different from that of iron. (orig.)

  19. Some pathophysiological and biochemical changes in dogs with different forms of lesions induced by inhalation of /sup 239/Pu and /sup 241/Am nitrates

    Kalmykova, Z.I.; Tokarskaya, Z.B.; Buldakov, L.A.; Nifatov, A.P.; Vedeneev, V.S.

    Dogs were acutely, subacutely and chronically inhaled with polymeric /sup 239/Pu and monomeric /sup 241/Am nitrates. Distinctly directed changes were observed in the protein fraction and glycoproteins, as well as in transaminases and sorbitoldehydrogenase of the blood serum, which were attributed to unequal radiation loads to the lungs and the organs of the secondary deposition of nuclides, and also to different degree of the respiratory distress.

  20. 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)

  1. US Transuranium Registry report on the 241Am content of a whole body. Part I: Introduction and history of the case

    The first whole-body analysis of the U.S. Transuranium Registry was initiated in 1979. The donor was a 49-yr-old male Caucasian radiochemist who died of metastatic malignant melanoma. The donor had a recognized, longstanding 241Am internal deposition first identified in a routine urine sample in 1958. A summary of the clinical and postmortem findings is presented with the chronologic sequence of the procedures

  2. The influence of the primary solutes in the study of the yield of alpha/beta discrimination in 241 Am and 210 Po

    We have studied the yields in efficiency and alpha/beta discrimination for two commercial cocktails, Ultima-Gold''TM AB and Insta-Gel and three laboratory-made mixtures made of Insta-Gel and naphthalene, pyrene or 9,10-diphenylanthracene. Also, we have tested the samples made of radioactive solutions of ''241 Am and ''210 Po in HNO3 of different concentrations in all scintillator solutions. (Author)

  3. New source-moderator geometry to improve performance of 252Cf and 241Am-Be source-based PGNAA setups

    The gamma ray yield from a 252Cf and a 241Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the 252Cf and the 241Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a 252Cf and a 241Am-Be source-based PGNAA setups

  4. New source-moderator geometry to improve performance of {sup 252}Cf and {sup 241}Am-Be source-based PGNAA setups

    Naqvi, A.A. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)]. E-mail: aanaqvi@kfupm.edu.sa; Abdelmonem, M.S. [Department of Physics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Al-Misned, Ghada [Girls Education College, Riyadh Girls Colleges, Riyadh (Saudi Arabia); Al-Ghamdi, Hanan [Girls Education College, Riyadh Girls Colleges, Riyadh (Saudi Arabia)

    2006-06-15

    The gamma ray yield from a {sup 252}Cf and a {sup 241}Am-Be source-based Prompt Gamma Ray Activation Analysis (PGNAA) setup has been observed to increase with enclosing their neutrons sources in a high-density polyethylene moderator. The prompt gamma rays yield from both setups depends upon the moderator length and the source position in it. For both setups, the optimum moderator length is found to be 7 cm. The optimum position of the neutron source inside moderator of the {sup 252}Cf and the {sup 241}Am-Be source-based PGNAA setups was found to be at a distance of 0.5 and 0.75 cm from the moderator-end facing the sample, respectively. Due to enclosure of the source in the moderator, about three-fold increase has been observed in the yield of prompt gamma rays from a Portland cement sample of a {sup 252}Cf and a {sup 241}Am-Be source-based PGNAA setups.

  5. 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)

  6. 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

  7. Radiosensitivity and proliferative activity of vertebral CFU-s surviving in mice injected with oncogenic activities of 239Pu or 241Am

    Survival, radiosensitivity and capability to produce differentiated progeny were studied in CFU-S from lumbar vertebrae of mice injected with 198.6 kBq 239Pu/kg or 208.6 kBq 241Am/kg. The CFU-S assay and 59Fe uptake by spleen colonies were used. The number of CFU-S from treated mice was significantly lower than in the controls. Higher radiosensitivity of CFU-S from 239Pu- or 241Am-treated mice was demonstrated using additional exposure to 0.5 Gy X-rays 1, 24, 48, 72 hrs after cell transplant and expressed more accurately by survival curves obtained 1 hr after the marrow cell injection. The effect of 239Pu on CFU-S was characterized by D0 0.58 Gy (n=0.91) and that of 241Am by D0 0.64 Gy (n=0.91); corresponding control values were D0 0.89 Gy, n=1.11. Lower iron utilization due not only to the decreased CFU-S numbers, but also to the defective production of erythrocytes per one CFU-S was found. The complexity of radiation effect on hematopoietic stem cells was demonstrated by the present study. (author)

  8. An improved in-house method for the determination of 241 Am in surface sediment within the exclusive economic zone of East Coast Peninsular Malaysia

    Present of 241 Am in the environment is being determined as part of surveillance and research programs related to nuclear activities. The separation of 241 Am from environmental samples was carried out against the IAEA reference material by using an improved in-house radiochemical separation method through anion exchange column, followed by the electro-deposition on a stainless steel disc, and finally assayed on alpha spectrometry counting system. The resulting spectra showed good isolated peak, indicating a good separation of the radionuclide of interest. The analytical results were in good agreement with the certified value for IAEA-326 and IAEA-368 with the calculated U-score was 0.36 and 0.82, respectively, showing no significant difference between the experimental and certified value. Using this method, distributions of 241 Am in seabed surface sediment in the Exclusive Economic Zone of East Coast Peninsular Malaysia were studied. Samples were collected during June 2008 where the concentrations of 241 were found to be ranged from < 0.08 to 0.36 Bq/kg, dry weight. (Author)

  9. Characterization of neutron flux spectra in the irradiation sites of a 37 GBq {sup 241}Am-Be isotopic source

    Yücel, Haluk [Ankara University, Institute of Nuclear Sciences, 06100 Tandogan, Ankara (Turkey); Budak, Mustafa Guray, E-mail: mbudak@gazi.edu.tr [Gazi University, Gazi Education Faculty, 06500 Teknikokullar, Ankara (Turkey); Karadag, Mustafa [Gazi University, Gazi Education Faculty, 06500 Teknikokullar, Ankara (Turkey); Yüksel, Alptuğ Özer [Ankara University, Institute of Nuclear Sciences, 06100 Tandogan, Ankara (Turkey)

    2014-11-01

    Highlights: • An irradiation unit was installed using a 37 GBq {sup 241}Am-Be neutron source. • The source neutrons moderated by using both water and paraffin. • Irradiation unit was shielded by boron oxide and lead against neutrons and gammas. • There are two sites for irradiations, one of them has a pneumatic transfer system. • Cadmium ratio method was used for irradiation site characterization. - Abstract: For the applicability of instrumental neutron activation analysis (NAA) technique, an irradiation unit with a 37 GBq {sup 241}Am-Be neutron source was installed at Institute of Nuclear Sciences of Ankara University. Design and configuration properties of the irradiation unit are described. It has two different sample irradiation positions, one is called site #1 having a pneumatic sample transfer system and the other is site #2 having a location for manual use. In order to characterize neutron flux spectra in the irradiation sites, the measurement results were obtained for thermal (φ{sub th}) and epithermal neutron fluxes (φ{sub epi}), thermal to epithermal flux ratio (f) and epithermal spectrum shaping factors (α) by employing cadmium ratios of gold (Au) and molybdenum (Mo) monitors. The activities produced in these foils were measured by using a p-type, 44.8% relative efficiency HPGe well detector. For the measured γ-rays, self-absorption and true coincidence summing effects were taken into account. Additionally, thermal neutron self-shielding and resonance neutron self-shielding effects were taken into account in the measured results. For characterization of site #1, the required parameters were found to be φ{sub th} = (2.11 ± 0.05) × 10{sup 3} n cm{sup −2} s{sup −1}, φ{sub epi} = (3.32 ± 0.17) × 10{sup 1} n cm{sup −2} s{sup −1}, f = 63.6 ± 1.5, α = 0.045 ± 0.009, respectively. Similarly, those parameters were measured in site #2 as φ{sub th} = (1.49 ± 0.04) × 10{sup 3} n cm{sup −2} s{sup −1}, φ{sub epi} = (2.93 ± 0

  10. Characterization of neutron flux spectra in the irradiation sites of a 37 GBq 241Am-Be isotopic source

    Highlights: • An irradiation unit was installed using a 37 GBq 241Am-Be neutron source. • The source neutrons moderated by using both water and paraffin. • Irradiation unit was shielded by boron oxide and lead against neutrons and gammas. • There are two sites for irradiations, one of them has a pneumatic transfer system. • Cadmium ratio method was used for irradiation site characterization. - Abstract: For the applicability of instrumental neutron activation analysis (NAA) technique, an irradiation unit with a 37 GBq 241Am-Be neutron source was installed at Institute of Nuclear Sciences of Ankara University. Design and configuration properties of the irradiation unit are described. It has two different sample irradiation positions, one is called site #1 having a pneumatic sample transfer system and the other is site #2 having a location for manual use. In order to characterize neutron flux spectra in the irradiation sites, the measurement results were obtained for thermal (φth) and epithermal neutron fluxes (φepi), thermal to epithermal flux ratio (f) and epithermal spectrum shaping factors (α) by employing cadmium ratios of gold (Au) and molybdenum (Mo) monitors. The activities produced in these foils were measured by using a p-type, 44.8% relative efficiency HPGe well detector. For the measured γ-rays, self-absorption and true coincidence summing effects were taken into account. Additionally, thermal neutron self-shielding and resonance neutron self-shielding effects were taken into account in the measured results. For characterization of site #1, the required parameters were found to be φth = (2.11 ± 0.05) × 103 n cm−2 s−1, φepi = (3.32 ± 0.17) × 101 n cm−2 s−1, f = 63.6 ± 1.5, α = 0.045 ± 0.009, respectively. Similarly, those parameters were measured in site #2 as φth = (1.49 ± 0.04) × 103 n cm−2 s−1, φepi = (2.93 ± 0.15) × 101 n cm−2 s−1, f = 50.9 ± 1.3 and α = 0.038 ± 0.008. The results for f-values indicate

  11. Determination of 106Ru, 134/137Cs, and 241Am concentrations and Action Level in the Foodstuffs Consumed by Inhabitants of Iraq

    *H. N. Majeed

    2013-03-01

    Full Text Available The specific activity concentrations of (106Ru, 134/137Cs, and 241Am nuclides in 40 imported foodstuffs which collected randomly in January 2012 from all Iraqi cities markets were studied. The rang of specific activity concentrations of 106Ru varies from (37.930±6.16 Bq kg-1 (S No. :17: Turkey Kidney bean to 99.735±9.99 Bq kg-1 (S No.:32: Egypt Broad bean, with average value 71.667±8.47 Bq kg-1. For 134Cs varies from 0.200±0.45 Bq kg-1 (S No. :19 : Ukraine Chick-pea to 2.365±1.54 Bq kg-1 (S No. :33 : Peru Broad bean with average value (0.988±0.99 Bq kg-1.The activity concentrations of 137Cs varies from 0.164±0.40 Bq kg-1 (S No.:19 : Ukraine Chick-pea to 5.291±2.30 Bq kg-1 ( S No.: 39: Uzbekistan Mung bean with average value 1.460±1.21, then for 241Am the activity concentrations varies from 0.029±0.17 Bq kg-1 (S No.:23 : Iran Chick-pea to 1.248±1.12 Bq kg-1 (S No.:40: Canada Green peas with average value 0.399±0.63. All the values were less than the World average concentrations [15,17]. The high contributor for 106Ru, 134/137Cs, and 241Am radionuclides were in Broad bean and other foodstuffs (which contained Brown grit, White grit, Mung bean and Green peas as a 12%, Broad bean as 14%, corn as a 19% and other foodstuffs with 15% respectively The lowest contributor of 106Ru, 134/137Cs, and 241Am radionuclides in the studied foodstuffs were 6% in cowpea, 7% in semolina, 5% in lentil and 4% in lentil respectively. The action level of the 106Ru, 134/137Cs, and 241Am radionuclide’s for three age groups have been calculated and the foodstuffs were within the range permitted and free of any radiation and thus there was no seriousness in dealing with.

  12. The total cross section and the fission cross section of 241Am in the resonance region. Resonance parameters

    The 241Am total and fission cross sections have been measured in the resonance region, using the 60MeV Saclay linac as a pulsed neutron source. The resonance parameters obtained by a single level shape analysis of the transmission data are given for 189 levels up to 150eV neutron energy. The mean level spacing, corrected for 18% of missed resonances in the 0 to 50eV energy range, is (0.55+-0.05)eV. The s-wave neutron strength function value, in the 0 to 150eV energy range, is equal to (0.94+-0.09)10-4. The average radiation width obtained from 43 resonances is (43.77+-0.72)MeV. Only preliminary results of the fission experiment are available now; 38 fission widths are given up to 32eV neutron energy, with the average value GAMMA(f) approximately equal to 0.23MeV; the statistical distribution of these fission widths corresponds to a X2 law with 4 degrees of freedom. An area analysis of the Los Alamos fission data has also been done, from which we obtain 36 GAMMA(f) values in the 20eV to 50eV energy range; the corresponding average value is: GAMMA(f) approximately equal to 0.52MeV; the statistical distribution obeys to a X2 law with 15 degrees of freedom, in desagreement with the Saclay results

  13. Radiosensitivity of vertebral bone marrow CFU-S surviving in mice internally contaminated with 239Pu or 241Am

    The radiosensitivity of pluripotent hemopoietic stem cells was studied in ICR ''Swiss'' mice (28 g/mouse) given i.v. 198.6 kBq 239Pu/kg as citrate complex or 208.6 kBq 241Am/kg as nitrate at the age of 10 weeks. The bone marrow cells were examined at the early and late phases of radionuclide contamination. To obtain data for survival curves and D0 of stem cells the CFU-S assay was used and the donor vertebral marrow cells were exposed to the complementary X-irradiation either early after injection to the heavily irradiated recipients or to the ''in vitro'' irradiation given before the transplantation. To determine the iron uptake in splenic erythroid progeny the recipients given marrow cells unexposed to the X-rays received 37 kBq 59Fe 6 h before they were killed and the relative activity per colony was calculated. The radiation effect of the used actinides on the bone marrow cells resulted in decreased cellularity and seriously altered both relative and absolute CFU-S numbers. The radiosensitivity of CFU-S increased in all intervals examined (D0 from 0.60 to 0.86 Gy, in controls 0.97 to 1.06 Gy) and was more expressed when the CFU-S were exposed to the X-rays immediately after the bone marrow cell transplantation to the heavily irradiated hosts. The stem cell pool appeared, especially at older age, to be affected also in its ability to produce erythrocytic progeny. (orig.)

  14. Hydration of the trivalent lanthanide ion 152Eu (III) in aqueous solutions at 298 K and similarity with the trivalent transplutonium element ion 241Am (III)

    Ionic self-diffusion coefficients data for 152Eu (III) and 241Am (III) are reported for concentrations of a supporting electrolyte of Gd(NO3)3-HNO3 or Nd(ClO4)3-HClO4 aqueous solutions up to 1.14 mol.L-1 at 2 C. The open-end capillary method (O.E.C.M.) is used for the determination of the ionic self-diffusion coefficients at pH = 2.50 labelled with tracers 152Eu (III) and 241Am (III). The fitting in polynomial forms of the experimental self-diffusion coefficients versus the square root of the ionic strength : - permits a comparison between the limiting diffusion coefficient value against the square root of the ionic strength and the limiting coefficients at infinite dilute solutions taken from conductimetric measurements in the literature using the Nernst-Einstein expression. - shows that the variation of D versus the square root of supporting electrolyte concentration is not linear in dilute solution. The divergence to the Onsager limiting law starts from 10-3 M and we aim to extend the validity range up to 0.2 M or more, by proposition of semi-empirical model with one adjustable parameter b. A study of Walden's law behaviour at variable concentrations can provide an interesting discussion for an eventual expression if the parameter b. The similarity in the ionic transport process (4f and 5f elements) leads us to conclude as a further consequence, it may be argued that of 152Eu (III) and 241Am (III) ions have the same hydration as a tripositive ion (with a comparable ionic radius) in the absence of hydrolysis, association and complexing (by choice of an acidic medium at pH 2.50)

  15. The subcellular distribution of 239Pu, 241Am and 59Fe in the liver of rat and Chinese hamster as dependent on time

    The subcellular distribution of monomeric 239Pu, 241Am and iron in rat and Chinese hamster liver has been investigated by sucrose-, metrizamide- and Percoll-density gradients. In rat liver, the transuranium elements become and remain bound to typical lysosomes up to several months after incorporation. Lysosomes are also the primary storage organelle in Chinese hamster liver. However, their apparent density in sucrose decreases with time, which possibly indicates transition into telolysomes. The transuranium nuclides show a subcellular distribution which is quite different from that of iron. (orig.)

  16. Improving the performance of 241Am-Be for PGNAA applications using a proper shielding for neutron source and the NaI detector

    Panjeh Hamed; Hakimabad Hashem M.; Motavalli Lalle R.

    2010-01-01

    The gamma ray spectrum resolution from a 241Am-Be source-based prompt gamma ray activation analysis set-up has been observed to increase in the energy region of interest with enclosing the NaI detector in a proper neutron and gamma ray shield. We have investigated the tact that the peak resolution of prompt gamma rays in the region of interest from the set-up depends on the source activity to the great extent, size and kind of the detector and the geometry of the detector shield. In ord...

  17. 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

  18. MCNP simulation of the incident and Albedo neutron response of the IRD Albedo Neutron Dosemeter for 241Am-Be moderated sources

    The IRD TLD Albedo dosemeter measures both incident and albedo neutron component. The incident to Albedo ratio is used to take into account the energy dependence of its response. In this paper, the behavior of the IRD Albedo dosemeter response as a function of the incident to Albedo ratio for 241Am-Be sources was simulated to improve its algorithm. The simulation was performed in MCNPX transport code and presents a good agreement with experimental measurements. The results obtained in this work are very useful to improve the accuracy of the IRD Albedo dosemeter at real neutron workplace. (author)

  19. The bioavailability of the transuranic elements 237Pu and 241Am for the pond snail, Lymnaea stagnalis L., and their behaviour in selected natural surface waters

    An attempt was made to characterise the bioavailability of 237Pu and 241Am for the pond snail Lymnaea stagnalis L. in selected surface waters. The uptake, distribution and retention patterns were studied through the contamination route water-snail. The effects of a number of parameters, such as seasonal variation, water type (pH, conductivity, ionic composition) and presence of food, on the bioavailability of the transuranics were evaluated. Finally, an assessment was made concerning the chemical speciation of plutonium and americium in the selected freshwaters

  20. 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)

  1. 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

  2. 241Am(n,γ) cross section in the neutron energy region between 0.02 eV and 300 keV

    The Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory (LANL) was used for a neutron capture cross section measurement on 241Am. The high granularity of the DANCE array (160 BaF2 detectors in a 4π geometry) enables an efficient detection of prompt gamma rays following neutron capture. The preliminary results on the 241Am(n,γ) cross section are presented from 0.02 eV to 300 keV. The cross section at thermal energy En = 0.0253 eV was determined to be 665±33 barns. Resonance parameters were obtained using the SAMMY7 fit to the measured cross section in the resonance region. Significant discrepancies were found between our results and data evaluations for the first three lowest lying resonances. The cross section for neutrons with En>l keV agrees well with the ENDF/B-VII.0 and JENDL-3.3 evaluations

  3. Effects of arctic temperatures on distribution and retention of the nuclear waste radionuclides 241Am, 57Co, and 137Cs in the bioindicator bivalve Macoma balthica

    Hutchins, D.A.; Stupakoff, I.; Hook, S.; Luoma, S.N.; Fisher, N.S.

    1998-01-01

    The disposal of radioactive wastes in Arctic seas has made it important to understand the processes affecting the accumulation of radionuclides in food webs in coldwater ecosystems. We examined the effects of temperature on radionuclide assimilation and retention by the bioindicator bivalve Macoma balthica using three representative nuclear waste components, 241Am, 57Co, and 137Cs. Experiments were designed to determine the kinetics of processes that control uptake from food and water, as well as kinetic constants of loss. 137Cs was not accumulated in soft tissue from water during short exposures, and was rapidly lost from shell with no thermal dependence. No effects of temperature on 57Co assimilation or retention from food were observed. The only substantial effect of polar temperatures was that on the assimilation efficiency of 241Am from food, where 10% was assimilated at 2??C and 26% at 12??C. For all three radionuclides, body distributions were correlated with source, with most radioactivity obtained from water found in the shell and food in the soft tissues. These results suggest that in general Arctic conditions had relatively small effects on the biological processes which influence the bioaccumulation of radioactive wastes, and bivalve concentration factors may not be appreciably different between polar and temperate waters.

  4. A Procedure for the Sequential Determination of Radionuclides in Environmental Samples. Liquid Scintillation Counting and Alpha Spectrometry for 90Sr, 241Am and Pu Radioisotopes

    Since 2004, IAEA activities related to the terrestrial environment have aimed at the development of a set of procedures to determine radionuclides in environmental samples. Reliable, comparable and ‘fit for purpose’ results are an essential requirement for any decision based on analytical measurements. For the analyst, tested and validated analytical procedures are extremely important tools for the production of analytical data. For maximum utility, such procedures should be comprehensive, clearly formulated and readily available for reference to both the analyst and the customer. This publication describes a combined procedure for the sequential determination of 90Sr, 241Am and Pu radioisotopes in environmental samples. The method is based on the chemical separation of strontium, americium and plutonium using ion exchange chromatography, extraction chromatography and precipitation followed by alpha spectrometric and liquid scintillation counting detection. The method was tested and validated in terms of repeatability and trueness in accordance with International Organization for Standardization (ISO) guidelines using reference materials and proficiency test samples. Reproducibility tests were performed later at the IAEA Terrestrial Environment Laboratory. The calculations of the massic activity, uncertainty budget, decision threshold and detection limit are also described in this publication. The procedure is introduced for the determination of 90Sr, 241Am and Pu radioisotopes in environmental samples such as soil, sediment, air filter and vegetation samples. It is expected to be of general use to a wide range of laboratories, including the Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA) network for routine environmental monitoring purposes

  5. 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)

  6. 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)

  7. 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).

  8. Mass accumulation rates and fallout radionuclides 210Pb, 137Cs and 241Am inventories determined in radiometrically dated abyssal sediments of the Black Sea

    Five abyssal (deep-sea) sediment cores collected during the two international cruises on R/V 'Professor Vodyanitskiy' (RADEUX-1998 and RADEUX-2000) in the framework of the Regional Technical Co-operation Project RER/2/003 'Marine Environmental Assessment in the Black Sea Region' were subjected to detailed radiometric analysis. The sediments were dated using the radionuclides 210Pb, 137Cs and 241Am and the results used to calculate a number of key parameters, e.g. radionuclide inventories, fluxes and sediment accumulation rates. The sediment cores were collected using a MARK II-400 multi-corer (Bowers and Connelly) in both Western and Eastern sub-basins of the Black Sea. The cores were sliced on board with a resolution of 0.2-0.4 cm for the top 5 cm and 1-5 cm downward using an extruder that was specially designed to prevent loss of the uppermost fluff-layer, possible down-smearing and interlayer cross-contamination of the sediment. Dry bulk density (DBD) and cumulative dry mass (CDM) were calculated on a salt-free basis using direct determination of the salt contribution to the dry mass of the sediment. Calculations showed that in the near surface sediments, and particularly in the top fluff-layer, the salt dissolved in pore-water contributed up to 30-60% of the mass of dried sediments. Neglecting this correction could cause an erroneous interpretation of the 210Pb activity profile, resulting in overestimation of both the average sedimentation rate and its recent temporal changes. Sediment samples were analysed for 210Pb, 226Ra, 137Cs and 241Am by direct gamma assay in UHMI after 3 weeks equilibration in hermetically sealed plastic holders, using an EG and G Ortec (Ametek) HPGe GWL series well-type coaxial low background intrinsic germanium detector. Correction was made for the effect of self-absorption of low energy γ-rays within the sample using attenuation parameters determined in. Chronostratigraphical analysis of the data and sediment age calculation have

  9. 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

  10. X-ray attenuation around -edge of Zr, Nb, Mo and Pd: A comparative study using proton-induced X-ray emission and 241Am gamma rays

    K K Abdullah; K Karunakaran Nair; N Ramachandran; K M Varier; B R S Babu; Antony Joseph; Rajive Thomas; P Magudapathy; K G M Nair

    2010-09-01

    Mass attenuation coefficients (/ρ) for Zr, Nb, Mo and Pd elements around their -edges are measured at 14 energies in the range 15.744–28.564 keV using secondary excitation from thin Zr, Nb, Mo, Rh, Pd, Cd and Sn foils. The measurements were carried out at the and energy values of the target elements by two techniques: (1) Proton-induced X-ray emission (PIXE) and (2) 241Am (300 mCi) source. In PIXE, 2 MeV proton-excited X-rays were detected by a Si(Li) detector. In the second case, X-rays excited by 59.54 keV photons from the targets were counted by an HPGe detector under a narrow beam good geometry set-up with sufficient shielding. The results are consistent with theoretical values derived from the XCOM package and indicate that the PIXE data have better statistical accuracy.

  11. Monte Carlo optimization of sample dimensions of an {sup 241}Am-Be source-based PGNAA setup for water rejects analysis

    Idiri, Z. [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz-Fanon, B.P. 399, 16000 Alger (Algeria)]. E-mail: zmidiri@yahoo.fr; Mazrou, H. [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz-Fanon, B.P. 399, 16000 Alger (Algeria); Beddek, S. [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz-Fanon, B.P. 399, 16000 Alger (Algeria); Amokrane, A. [Faculte de Physique, Universite des Sciences et de la Technologie Houari-Boumediene (USTHB), Alger (Algeria); Azbouche, A. [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz-Fanon, B.P. 399, 16000 Alger (Algeria)

    2007-07-21

    The present paper describes the optimization of sample dimensions of a {sup 241}Am-Be neutron source-based Prompt gamma neutron activation analysis (PGNAA) setup devoted for in situ environmental water rejects analysis. The optimal dimensions have been achieved following extensive Monte Carlo neutron flux calculations using MCNP5 computer code. A validation process has been performed for the proposed preliminary setup with measurements of thermal neutron flux by activation technique of indium foils, bare and with cadmium covered sheet. Sensitive calculations were subsequently performed to simulate real conditions of in situ analysis by determining thermal neutron flux perturbations in samples according to chlorine and organic matter concentrations changes. The desired optimal sample dimensions were finally achieved once established constraints regarding neutron damage to semi-conductor gamma detector, pulse pile-up, dead time and radiation hazards were fully met.

  12. Measurement and Analysis of $^{241}$Am(n,γ) Cross Sections with C$_6$D$_6$ Detectors at the n_TOF Facility at CERN

    Fraval, K; Mastromarco, M; Meaze, M; Mendoza, E; Mengoni, A; Milazzo, P M; Mingrone, F; Mirea, M; Mondalaers, W; Paradela, C; Pavlik, A; Perkowski, J; Plompen, A; Praena, J; Quesada, J M; Rauscher, T; Reifarth, R; Riego, A; Roman, F; Rubbia, C; Sarmento, R; Schillebeeckx, P; Schmidt, S; Tagliente, G; Tain, J L; Tarrío, D; Tassan-Got, L; Tsinganis, A; Valenta, S; Vannini, G; Variale, V; Vaz, P; Ventura, A; Versaci, R; Vermeulen, M J; Vlachoudis, V; Vlastou, R; Wallner, A; Ware, T; Weigand, M; Weiß, C; Wright, T; Žugec, P

    The 241Am(n,γ) cross sections have been measured at the n_TOF facility at CERN using C6D6 liquid scintillators and time of flight spectrometry. The results in the resolved resonance range bring new constraints to evaluations below 150 eV, and the energy upper limit can be extended from 150 eV to 320 eV. The analysis goes from thermal energy to 150 keV, and the unresolved resonance range cross section turns out to be larger than expected by evaluations or otherwise measured by previous works. The thermal cross section is found to be σthσth = 740 ± 74 barns, which is larger than expected by evaluations and most previous measurements.

  13. Measurement of the neutron-induced fission cross-section of {sup 241}Am at the time-of-flight facility n{sub T}OF

    Belloni, F.; Milazzo, P.M.; Abbondanno, U.; Fujii, K.; Moreau, C. [Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); Calviani, M. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); CERN, Geneva (Switzerland); Colonna, N.; Barbagallo, M.; Marrone, S.; Meaze, M.H.; Tagliente, G.; Terlizzi, R. [Istituto Nazionale di Fisica Nucleare (INFN), Bari (Italy); Mastinu, P.; Gramegna, F. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Gunsing, F.; Perrot, L.; Plukis, A. [Irfu, CEA, Gif-sur-Yvette (France); Alvarez, H.; Cano-Ott, D.; Duran, I.; Embid-Segura, M.; Gonzalez-Romero, E.; Paradela, C.; Tarrio, D. [Universidade de Santiago de Compostela, Santiago de Compostela (Spain); Alvarez-Velarde, F.; Guerrero, C.; Martinez, T.; Villamarin, D.; Vincente, M.C. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andrzejewski, J.; Marganiec, J. [University of Lodz, Lodz (Poland); Audouin, L.; Dillmann, I.; Heil, M.; Kaeppeler, F.; Mosconi, M.; Plag, R.; Voss, F.; Walter, S.; Wisshak, K. [Institut fuer Kernphysik, Karlsruhe Institute of Technology, Campus Nord, Nord (Germany); Badurek, G.; Jericha, E.; Leeb, H.; Oberhummer, H. [Technische Universitaet Wien, Atominstitut der Oesterreichischen Universitaeten, Wien (Austria); Baumann, P.; David, S.; Kerveno, M.; Lukic, S.; Rudolf, G. [Centre National de la Recherche Scientifique/IN2P3 - IReS, Strasbourg (France); Becvar, F.; Krticka, M. [Charles University in Prague, Faculty of Mathematics and Physics, Prague (Czech Republic); Calvino, F.; Cortes, G.; Poch, A.; Pretel, C. [Universitat Politecnica de Catalunya, Barcelona (Spain); Capote, R. [NAPC/Nuclear Data Section, International Atomic Energy Agency (IAEA), Vienna (Austria); Universidad de Sevilla, Sevilla (Spain)] [and others

    2013-01-15

    The neutron-induced fission cross-section of {sup 241}Am has been measured relative to the standard fission cross-section of {sup 235}U between 0.5 and 20 MeV. The experiment was performed at the CERN n{sub T}OF facility. Fission fragments were detected by a fast ionization chamber by discriminating against the {alpha} -particles from the high radioactivity of the samples. The high instantaneous neutron flux and the low background of the n{sub T}OF facility enabled us to obtain uncertainties of {approx} 5%. With the present results it was possible to resolve discrepancies between previous data sets and to confirm current evaluations, thus providing important information for design studies of future reactors with improved fuel burn-up. (orig.)

  14. A radiochemical procedure for a low-level measurement of ''241 Am in environmental samples using a supported functional organo phosphorus extractant

    The transuranides analysis in environmental samples is carried out by CIEMAT using standardized methods based on sequential separation with ionic-exchange resins. The americium fraction is purified through a two-layer ion exchange column and lately in an anion-exchange column in nitric acid methanol medium. The technique is time-consuming and the results are not completely satisfactory (low recovery and loss of alpha-resolution) for some samples. The chemical compound CMPO (octyl(phenyl).N,N-diisobutyl carbomoylmethyiphosphine oxide) dissolved in TPB (tributyl phosphate) and supported on an inert substrate has been tested directly for ''241 Am analysis by a large number of laboratories. A new method that combines both procedures has been developed. The details of the improved procedure are described in this paper. The advantages of its application to environmental samples (urine, faeces and sediments) are discussed. The utilization of standard, with americium certified concentrations confirms the reliability of our measurements

  15. 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

  16. 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

  17. {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

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

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

    2007-02-01

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

  19. Calibration Human Voxel Phantoms for In Vivo Measurement of ''241 Am in Bone at the Whole Body Counter Facility of CIEMAT

    The Whole Body Counting facility of CIEMAT is capable of carrying out In-Vivo measurements of radionuclides emitting X-rays and low energy gamma radiation internally deposited in the body. The system to use for this purpose consists of flour Low energy Germanium (LeGe) Camberra detectors working in the energy range from 10 to 1000 keV. Physical phantoms with a known contamination in the organ of interest are normally used for the calibration of the LEGe detection system. In this document we present a calibration method using the Monte Carlo technique (MCNP4C) over a voxel phantom obtained from a computerized tomography of a real human head. The phantom consists of 104017 (43x59x41) cubic voxels, 4 mn on each side, os specific tissues, but for this simulation only two types are taken into account: adipose tissue and hard bone. The skull is supposed to be contaminated with ''241 Am and the trajectories of the photons are simulated till they reach the germanium detectors. The detectors were also simulated in detail to obtain a good agreement with the reality. In order to verify the accuracy of this procedure to reproduce the experiments, the MCNP results are compared with laboratory measurements of a head phantom simulating an internal contamination of 1000 Bq of ''241 Am deposited in bone. Different relative positions source-detector were tried to look for the best counting geometry for measurement of a contaminated skull. Efficiency values are obtained and compared, resulting in the validation of the mathematical method for the assessment of internal contamination of American deposited in skeleton. (Author) 16 refs

  20. Calibration Human Voxel Phantoms for In Vivo Measurement of ''241 Am in Bone at the Whole Body Counter Facility of CIEMAT

    Moraleda, M.; Lopez, M. A.; Gomez Ros, J. M.; Navarro, T.; Navarro, J. F.

    2002-07-01

    The Whole Body Counting facility of CIEMAT is capable of carrying out In-Vivo measurements of radionuclides emitting X-rays and low energy gamma radiation internally deposited in the body. The system to use for this purpose consists of flour Low energy Germanium (LeGe) Camberra detectors working in the energy range from 10 to 1000 keV. Physical phantoms with a known contamination in the organ of interest are normally used for the calibration of the LEGe detection system. In this document we present a calibration method using the Monte Carlo technique (MCNP4C) over a voxel phantom obtained from a computerized tomography of a real human head. The phantom consists of 104017 (43x59x41) cubic voxels, 4 mn on each side, os specific tissues, but for this simulation only two types are taken into account: adipose tissue and hard bone. The skull is supposed to be contaminated with ''241 Am and the trajectories of the photons are simulated till they reach the germanium detectors. The detectors were also simulated in detail to obtain a good agreement with the reality. In order to verify the accuracy of this procedure to reproduce the experiments, the MCNP results are compared with laboratory measurements of a head phantom simulating an internal contamination of 1000 Bq of ''241 Am deposited in bone. Different relative positions source-detector were tried to look for the best countring geometry for measurement of a contaminated skull. Efficiency values are obtained and compared, resulting in the validation of the mathematical method for the assessment of internal contamination of American deposited in skeleton. (Author) 16 refs.

  1. Determination of the transfer coefficients between oyster's mushrooms and their cultivation media by using of isotopes 239Pu and 241Am

    Mushrooms are unicellular or poly-cellular organisms, which are feed lateral or saprophytic. Mainly their cells have developed cellular sheet and definite form. Poly-cellular mushrooms generate the fibers, called hypes, which make twine, called mycelium, which side as feeding tissue. From mycelium grow fertile body, which have reproductive function. These fertile bodies with their speed and period of grow, as possible bio-indicators of contamination biosphere by heavy metals, present applicable matrix for analysis. In this work we try to find a way of using fungus to clean up soil contaminated with radioactive waste, especially plutonium and americium. The completely natural method, called myco-remediation or fungal remediation, which was successfully used for clean up soil contaminated with petroleum hydrocarbons and other toxic or hazardous waste, is expected to be faster and more cost-effective than other bioremediation techniques. The analyzed radionuclides were determined using by followed algorithm - the Pu was separated by liquid extraction with Aliquat-336 and for the determination of Am was used liquid extraction with TOPO. For the determination of chemical recovery was used tracer 242Pu with activity 5,0.10-2 Bq, respectively 243Am with activity 1.28.10-1 Bq. The samples after separation were precipitated, micro-filtrated and follow measured by α-spectrometer Ortec. (author)

  2. 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

  3. Improving the performance of 241Am-Be for PGNAA applications using a proper shielding for neutron source and the NaI detector

    Panjeh Hamed

    2010-01-01

    Full Text Available The gamma ray spectrum resolution from a 241Am-Be source-based prompt gamma ray activation analysis set-up has been observed to increase in the energy region of interest with enclosing the NaI detector in a proper neutron and gamma ray shield. We have investigated the tact that the peak resolution of prompt gamma rays in the region of interest from the set-up depends on the source activity to the great extent, size and kind of the detector and the geometry of the detector shield. In order to see the role of a detector shield, five kinds of the detector shield were used and finally the proper kind was introduced. Since the detector shield has an important contribution in the reduction of the undesirable and high rate gamma rays coming to the gamma ray detector, a good design of a proper shield enables the elimination of the unwanted events, such as a pulse pile-up. By improving the shielding design, discrete and distinguishable photoelectric peaks in the energy region of interest have been observed in the spectrum of prompt gamma rays.

  4. Estimation of multi-group cross section covariances for 235,238U, 239Pu, 241Am, 56Fe, 23Na and 27Al

    This paper presents the methodology used to estimate multi-group covariances for some major isotopes used in reactor physics. The starting point of this evaluation is the modelling of the neutron induced reactions based on nuclear reaction models with parameters. These latest are the vectors of uncertainties as they are absorbing uncertainties and correlation arising from the confrontation of nuclear reaction model to microscopic experiment. These uncertainties are then propagated towards multi-group cross sections. As major breakthroughs were then asked by nuclear reactor physicists to assess proper uncertainties to be used in applications, a solution is proposed by the use of integral experiment information at two different stages in the covariance estimation. In this paper, we will explain briefly the treatment of all type of uncertainties, including experimental ones (statistical and systematic) as well as those coming from validation of nuclear data on dedicated integral experiment (nuclear data oriented). We will illustrate the use of this methodology with various isotopes such as 235,238U, 239Pu, 241Am, 56Fe, 23Na and 27Al. (authors)

  5. Investigation on biokinetics of 134Cs and 241Am radionuclides in three different organisms and a new evaluation by using discrete time model

    In this study, 134Cs and 241Am biokinetic experiments have been observed originally for Black Sea condition with using the gastropod Patella coerulea and the macro algae Enteremorpha linza and the common mussel Mytilus galloprovlncialis as bio indicator organisms. The experiments that have at least three originality, have been carried out very carefully and biokinetic parameters have been calculated by using classical model. The results are compared with the proportionally similar experiments in the literature globally. In this thesis, a new model application has proposed for the biokinetic evaluation for loss experiments of organisms. That is discrete time model. Loss experiments can be evaluated proportionally in a quick and easy way by using this model. Then, it can be observed that the calculated decreasing factor (r) by discrete time model, shows the loss process quality. Moreover, the loss experiments can be stopped when the decreasing factor goes to 1. So, the loss experiment can be evaluated rapidly and quickly with the adequate reliability by using discrete time model. Furthermore, the loss process in the organisms becomes slower and biologic half-lives becomes longer, when the decreasing factor (r) goes to 1. On the other hand, the biological depuration rate (k) goes to nearly zero. So, the proposed discrete time model that is applied in this thesis originally for biokinetic, can be evident that it has an adequate reliability for the biokinetic evaluation

  6. 241Am-photonabsorptiometry in patients with chronic renal failure, with particular reference to the effect of 1-alpha-hydroxyvitamin D3

    The study was undertaken in patients with chronic renal failure (CRF patients) in order to evaluate 1) the degree and course of skeletal demineralization and 2) the effect on the bone mineral content (BMC) of long-term treatment with 1α-hydroxyvitamin D3 (1α(OH)D3). BMC was measured on the radius by 241Am-photonabsorptiometry and the results were corrected for age, sex and bone width. In a cross-sectional study BMC was measured in 191 normal subjects and in 88 renal patients. In a controlled longitudinal trial 22 CRF patients were treated for 25.6 months with 1α(OH)D3, while 22 CRF patients did not receive vitamin D supplements. In non-treated CRF-patients an accelerated bone loss (approx. equal to 3%/year) and a significantly reduced BMC (mean 87.2% of normal) was found. In the 1α(OH)D3 treated patients BMC increased on an average 0.9%/year, significantly different from the continued bone loss recorded in the nontreated control patients. The data indicate that 1) CRF patients via accelerated bone loss develop reduced bone mass, and 2) cessation of this bone loss may be achieved by long-term treatment with 1α(OH)D3. (orig.)

  7. 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

  8. 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.

  9. 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

  10. Freestanding single crystal chemical vapor deposited diamond films produced using a lift-off method: Response to α-particles from 241Am and crystallinity

    Thick (∼100 μm) undoped diamond films were grown homoepitaxially on single crystal (SC) diamond substrates by microwave plasma chemical vapor deposition (CVD). To form a freestanding SC diamond film (plate), the substrate was pre-ion-implanted with high-energy ion beams before the film growth, and after the thick-film deposition, the substrate was eliminated using a lift-off method, resulting in fabrication of a SC CVD diamond plate. Two samples were prepared; sample 1 was grown on a (0 0 1) oriented, nitrogen doped CVD SC diamond at ∼900 °C with the input microwave power of 1.7 kW, while sample 2 was grown on a (0 0 1) oriented, high-pressure high-temperature synthesized type-Ib SC diamond at ∼900 °C with the input microwave power of 1.25 kW. The formed SC plates have high optical transparencies, indicating no remarkable optical absorptions seen in the wavelength from ultraviolet to near infrared. The photoluminescence (PL) spectra of both samples show strong free exciton FE peaks, while in sample 2 relatively strong optical emissions corresponding to nitrogen related centers were observed in the visible region. After the metal electrodes were formed on both faces of the SC diamond plate to fabricate a sandwich-type diamond particle detector, the energy spectra of 5.486 MeV α-particles from 241Am were measured. The charge collection efficiencies (CCEs) of sample 1 were CCE = 98% for a hole transport and CCE = 89% for an electron transport, respectively, while CCEs of sample 2 were CCE = 80% for a hole transport and CCE = 78% for an electron transport, respectively. These results indicate that both holes and electrons in sample 2 were trapped much more than those in sample 1. Possible candidates of carrier capture centers are nitrogen and/or nitrogen-vacancy centers observed in PL, nonradiative defect (complex) centers, extended defects such as threading dislocations observed in micrographs taken with polarizers. The different growth conditions most

  11. Transfer and translocation of {sup 241}Am, {sup 239}Pu, {sup 137}Cs and {sup 85}Sr after partial foliar contamination of bean plants

    Henner, P.; Colle, C.; Morello, M. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

    2004-07-01

    Bean plants at the flowering development stage were contaminated by soaking their two first leaves for 3 hours in a solution containing one of the actinides {sup 241}Am or {sup 239}Pu, or both {sup 137}Cs and {sup 85}Sr. The aim of the study was to assess the adequacy of using the values of Cs/Sr for the foliar transfer parameters of transuranic actinides, as used for example in the ASTRAL code to calculate the contamination of agricultural products after a nuclear accident. Secondly, these experiments were launched to tentatively determine specific values for the foliar transfer parameters for Am and Pu, despite technical limitations due to high radiotoxicity of these isotopes which prevented the contamination of the whole foliage of bean plants. Cs and Sr were used to compare the results with those obtained with other modes of contamination, by dry deposition of aerosols for example. Results showed that the soaking protocol was adequate to compare the foliar transfer of various radionuclides, although it should be difficult to provide specific values because of partial contamination of the foliage. Foliar transfer factors, expressed as Bq.kg{sup -1}{sub dw} {sub pods}/Bq.L{sup -1}{sub solution} (2.5x10{sup -2}) and translocation factors, dimensionless, (2.3x10{sup -3}) for Am and for Pu (1.5x10{sup -3} and 7.5x10{sup -5} respectively), compared to those for Sr (respectively 3.6x10{sup -3} and 5.9x10{sup -4}) and for Cs (respectively 2.9x10{sup -1} and 1.3x10{sup -1}), were studied using this procedure. Transfer and translocation factors for Am were significantly higher than those for Sr, but were smaller than those for Cs. Therefore, Am can be classified as a medium mobile radionuclide in plant. Transfer and translocation of Pu were significantly lower than these for Sr and for Am. Besides, the transfer and translocation factors of Am and Pu only differed from one order of magnitude or less from the one of Sr, which could be in the usual range of variation

  12. A radiochemical procedure for a low-level measurement of ''241Am in environmental samples using a supported functional organo phosphorus extractant; Metodo analitico para la determinacion de ''241Am en muestras biologicas y sedimentos marinos mediante uso de una columna con extractante organico

    Gasco, C.; Anton, M. P.; Alvarez, A.; Navarro, N.; Salvador, S.

    1994-07-01

    The transuranides analysis in environmental samples is carried out by CIEMAT using standardized methods based on sequential separation with ionic-exchange resins. The americium fraction is purified through a two-layer ion exchange column and lately in an anion-exchange column in nitric acid methanol medium. The technique is time consuming and the results are not completely satisfactory (low recovery and loss of a-resolution) for some samples. The chemical compound CMPO (octyl(phenyl)-N,N-diisobutyl carbomoylmethyiphosphine oxide) dissolved in TPB (tributyl phosphate) and supported on an inert substrate has been tested directly for ''241Am analysis by a large number of laboratories. A new method that combines both procedures has been developed. The details of the improved procedure are described in this paper. The advantages of its application to environmental samples (urine, faeces and sediments) are discussed. The utilization of standard samples, with americium certified concentrations confirms the reliability of our measurements. (Author) 8 refs.

  13. 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)

  14. 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)

  15. An experimental investigation of M-subshell fluorescence yields and of the L1-L3 radiative transition in neptunium and curium from the radioactive decays of 241Am and 249Cf

    The construction and performance of a wall-less multiwire proportional counter (MWPC) is described. The absolute emission rate of M x rays from a 241Am source was measured with the MWPC and with a single-wire proportional counter and a value of (6.35 +- 0.60) x 10-2 M x rays per decay, or (0.470 +- 0.045) M x rays per L/sub α/ x ray is obtained. High resolution Ge(Li) and Si(Li) x-ray spectrometers and the multiwire proportional counter (MWPC) were used for measuring coincidences, respectively, between various L x rays and the M x rays of neptunium (Z = 93) from a 241Am source. In addition, M x rays of curium from a 249Cf source were measured with a Si(Li) detector in coincidence with various K and L x rays detected with a Ge(Li) spectrometer. 81 refs., 24 figs., 23 tabs

  16. Nuclear data evaluation for 237Np, 241Am, 242gAm and 242mAm irradiated by neutrons and protons at energies up to 250 MeV

    Evaluation of nuclear data has been performed for 237Np, 241Am, 242gAm and 242mAm. Neutron data were obtained at energies from 20 to 250 MeV and combined with JENDL-3.3 data at 20 MeV. Evaluation of the proton data has been done from 1 to 250 MeV. The coupled channel optical model was used to obtain angular distributions for elastic and inelastic scattering and transmission coefficients. Pre-equilibrium exciton model and Hauser-Feshbach statistical model were used to describe neutron and charged particles emission from excited nuclei. These evaluation is the first work for producing full sets of evaluated file up to 250 MeV for 237Np and Americium isotopes. (author)

  17. Neutron monitor calibration with 241AmBe(α, n), 252Cf , 252Cf+D2O and 238PuBe(α, n) used in dose evaluation near Linac

    The use of linear accelerators in Radiotherapy is becoming increasingly more common. From the Radiation Protection point of view, these instruments represent an advance relative to cobalt and caesium irradiators, mainly due to the absence of radioactive material. On the other hand, accelerators with energies over 10 MeV contaminate with neutrons the therapeutic beam. These neutrons are generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. Photo-neutrons can also interact with other materials, present in the treatment room, consequently modifying the initial spectrum and causing other types of interactions which privilege the gamma capture. In this way, the measurement of the photo-neutron spectrum can be necessary in a radiometric survey. The present work carries through measurements in a linear accelerator of 15 MeV using three neutron area monitors calibrated using four radioactive sources: three ISO reference sources, 241AmBe (α, n), 252Cf (f, n) and 252Cf+D2O, and a 238PuBe(α, n) source. As the three first sources, this last one was standardized in the LMNRI/IRD manganese bath system. Comparison and evaluation of the response of these instruments were thereby made, analyzing whether the reading of the detectors using standard sources is adequate. In conclusion, the analysis of the response of neutron area calibrated detectors enable the use of them in an environment containing medical linear accelerator. (author)

  18. Neutron monitor calibration with {sup 241}AmBe({alpha}, n), {sup 252}Cf , {sup 252C}f+D{sub 2}O and {sup 238}PuBe({alpha}, n) used in dose evaluation near Linac

    Salgado, Ana Paula; Pereira, Walsan Wagner; Patrao, Karla Cristina de Souza; Fonseca, Evaldo Simoes da [Instituto de Radioprotecao e Dosimetria (IRD-CNEN/RJ), Rio de Janeiro, RJ (Brazil). Lab. de Neutrons], e-mail: asalgado@ird.gov.br

    2009-07-01

    The use of linear accelerators in Radiotherapy is becoming increasingly more common. From the Radiation Protection point of view, these instruments represent an advance relative to cobalt and caesium irradiators, mainly due to the absence of radioactive material. On the other hand, accelerators with energies over 10 MeV contaminate with neutrons the therapeutic beam. These neutrons are generated when high-energy photons interact with high-atomic-number materials such as tungsten and lead present in the accelerator itself. Photo-neutrons can also interact with other materials, present in the treatment room, consequently modifying the initial spectrum and causing other types of interactions which privilege the gamma capture. In this way, the measurement of the photo-neutron spectrum can be necessary in a radiometric survey. The present work carries through measurements in a linear accelerator of 15 MeV using three neutron area monitors calibrated using four radioactive sources: three ISO reference sources, {sup 241}AmBe ({alpha}, n), {sup 252}Cf (f, n) and 252{sup C}f+D{sub 2}O, and a 238{sup P}uBe({alpha}, n) source. As the three first sources, this last one was standardized in the LMNRI/IRD manganese bath system. Comparison and evaluation of the response of these instruments were thereby made, analyzing whether the reading of the detectors using standard sources is adequate. In conclusion, the analysis of the response of neutron area calibrated detectors enable the use of them in an environment containing medical linear accelerator. (a0011uth.

  19. Manufacture Quasi-monochromatic X-ray Machine to Replace 241 Am Low Energy Photon Source%替代241Am低能光子源的准单色X射线机的研制

    林辉; 肖雪夫; 赵靖; 简利民

    2014-01-01

    研究了用滤光片法产生50~60 keV的准单色X射线的条件,对输出的X射线进行了数种金属滤光片实验研究,选出合适的滤光片,通过实验对准直器的机械结构进行了确定。采用自行设计委托加工的X射线管、准直器和购买的高压电源,组装成符合实验要求的X射机。该装置输出了50~60 keV能量段的准单色光谱,在料位计上能替代241 Am低能光子源。%A practical approach to produce 50-60 keV quasi-monochromatic X-ray by selection metal filter was studied .The appropriate metal filter was selected after various types of filters were tested . The mechanical structure of the collimator was also determined . According to the experimental requirement , a X-ray machine was assembled with a X-ray tube ,a collimator and an ultrahigh voltage power source .This device generates standard spectrum of quasi-monochromatic X-ray in the energy range of 50-60 keV ,and the X-ray machine can present an appropriate substitution to 241 Am low energy photon source in the traditional level indicator .

  20. Contamination of seven workers with 241Am

    Widespread contamination occurred in the building in which radiation waste was handled. An occurrence of internal contamination of workers was also suspected. Therefore, workers were measured in vivo and bioassay was performed too. Estimation of committed effective dose had to be based on results of excretion analysis as irremovable surface contamination occurred on the skin and hair of workers, thus influencing results of in vivo measurements. The results of bioassay of 7 workers are presented. Intakes and committed effective doses were calculated from excretion data using IMBA Professional Plus software. The best fits for the most of workers were obtained when combination of acute and chronic intakes was used. Acute intakes varied from 135 Bq to 1300 Bq, chronic intakes from 0.03 Bq/d to 0.3 Bq/d. Committed effective doses from 3 to 36 mSv were estimated for individual workers. (author)

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

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

  2. Contamination of seven workers with {sup 241}Am; Contaminations de sept travailleurs par {sup 241}Am

    Malatova, I.; Beckova, V.; Pospisilova, H.; Filgas, R. [National Radiation Protection Institute, Praha (Czech Republic)

    2005-10-15

    Widespread contamination occurred in the building in which radiation waste was handled. An occurrence of internal contamination of workers was also suspected. Therefore, workers were measured in vivo and bioassay was performed too. Estimation of committed effective dose had to be based on results of excretion analysis as irremovable surface contamination occurred on the skin and hair of workers, thus influencing results of in vivo measurements. The results of bioassay of 7 workers are presented. Intakes and committed effective doses were calculated from excretion data using IMBA Professional Plus software. The best fits for the most of workers were obtained when combination of acute and chronic intakes was used. Acute intakes varied from 135 Bq to 1300 Bq, chronic intakes from 0.03 Bq/d to 0.3 Bq/d. Committed effective doses from 3 to 36 mSv were estimated for individual workers. (author)

  3. Measurement of fission cross-section of actinides at n_TOF for advanced nuclear reactors

    Calviani, Marco; Montagnoli, G; Mastinu, P

    2009-01-01

    The subject of this thesis is the determination of high accuracy neutron-induced fission cross-sections of various isotopes - all of which radioactive - of interest for emerging nuclear technologies. The measurements had been performed at the CERN neutron time-of-flight facility n TOF. In particular, in this work, fission cross-sections on 233U, the main fissile isotope of the Th/U fuel cycle, and on the minor actinides 241Am, 243Am and 245Cm have been analyzed. Data on these isotopes are requested for the feasibility study of innovative nuclear systems (ADS and Generation IV reactors) currently being considered for energy production and radioactive waste transmutation. The measurements have been performed with a high performance Fast Ionization Chamber (FIC), in conjunction with an innovative data acquisition system based on Flash-ADCs. The first step in the analysis has been the reconstruction of the digitized signals, in order to extract the information required for the discrimination between fission fragm...

  4. ANSI/ANS-8.15-1981(R87): Nuclear criticality control of special actinide elements

    The American National Standard, open-quotes Nuclear Criticality Safety in Operations with Fissionable Materials Outside Reactotorsclose quotes American National Standards Institute/American Nuclear Society (ANSI/ANS)-8.1-1983(R88) provides guidance for the nuclides 233U, 235U, and 239Pu. These three nuclides are of primary interest in out-of-reactor criticality safety since they are the most commonly encountered in the vast majority of operations. However, some operations can involve nuclides other than 233U, 235U, and 239Pu in sufficient quantities that their effect on criticality safety could be of concern. ANSI/ANS-8.15-1981(R87) open-quotes Nuclear Criticality Control of Special Actinide Elements,close quotes provides guidance for 15 such nuclides. The standard was approved for use on November 9, 1981. When it received its first 5-yr review, no changes were made, and it was reaffirmed effective October 30, 1987. The standard was again reviewed and reaffirmed without changes in December 1995. The next 5-yr review of the standard is due in December 2000. The affected nuclides are 237Np, 238Pu, 240Pu, 242Pu, 241Am, 243Am, 244Cm, 239Pu, 241Pu, 242mAm, 243Cm, 245Cm, 247Cm, 249Cf, and 251Cf

  5. 241Am INGROWTH AND ITS EFFECT ON INTERNAL DOSE.

    Konzen, Kevin

    2016-07-01

    Generally, plutonium has been manufactured to support commercial and military applications involving heat sources, weapons, and reactor fuel. This work focuses on three typical plutonium mixtures while observing the potential of Am ingrowth and its effect on internal dose. The term "ingrowth" is used to describe Am production due solely to the decay of Pu as part of a plutonium mixture, where it is initially absent or present in a smaller quantity. Dose calculation models do not account for Am ingrowth unless the Pu quantity is specified. This work suggested that Am ingrowth be considered in bioassay analysis when there is a potential of a 10% increase to the individual's committed effective dose. It was determined that plutonium fuel mixtures, initially absent of Am, would likely exceed 10% for typical reactor grade fuel aged less than 30 y; however, heat source grade and aged weapons grade fuel would normally fall below this threshold. Although this work addresses typical plutonium mixtures following separation, it may be extended to irradiated commercial uranium fuel and is expected to be a concern in the recycling of spent fuel. PMID:27218291

  6. Determination of 241Am and 244Cm in environmental samples

    The present technique describes a method to separate, purify and measure low levels of americium and curium in different environmental samples such as sediments, soils, water, vegetables, and air filters. The determination of radionuclides in theses environmental matrices have analytical problems, since a simple method doesn't exist for the purification, which is indispensable for its later measuring alpha spectrometry. The developed technique consist on taking an aliquot of the sample to analyze, to add tracer as americium 243 and curium 242, and to dissolve the matrix in a such way to have a clear solution. For the isolation of the americium and curium of the other actinides ar used as separation techniques: precipitation with Fe3+, anionic and cationic exchange, and extraction with a appropriate organic solvent. The purification of the americium and curium is followed by the electrodeposition habitually used. The measurement is carried out by alpha spectrometry with a detector of implanted ion. The detection limit for this techniques is of 0,002 Bq/l or 0,2 mBq in the case of filters. (author)

  7. Medical grade 238Pu from 241Am: progress report

    Shielding requirements for fabrication of americium targets were evaluated, a preliminary flowsheet for processing the irradiated Am targets was developed, and the AMRAD computer program, which models the irradiation cycle, was improved

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

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

    2004-07-01

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

  9. Analysis of americium-beryllium neutron source composition using the FRAM code

    Hypes, P. A. (Philip A.); Bracken, D. S. (David S.); Sampson, Thomas E.; Taylor, W. A. (Wayne A.)

    2002-01-01

    The FRAM code was originally developed to analyze high-resolution gamma spectra from plutonium items. Its capabilities have since been expanded to include analysis of uranium spectra. The flexibility of the software also enables a capable spectroscopist to use FRAM to analyze spectra in which neither plutonium nor uranium is present in significant amounts. This paper documents the use of FRAM to determine the {sup 239}Pu/{sup 241}Am, {sup 243}Am/{sup 241}Am, {sup 237}Np/{sup 241}Am, and {sup 239}Np/{sup 241}Am ratios in americium-beryllium neutron sources. The effective specific power of each neutron source was calculated from the ratios determined by FRAM in order to determine the americium mass of each of these neutron sources using calorimetric assay. We will also discuss the use of FRAM for the general case of isotopic analysis of nonplutonium, nonuranium items.

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

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

    2007-08-28

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

  11. The production of transplutonium elements in France

    The development of the program for the production of transplutonium elements, 241Am, 243Am and 244Cm, in France, required a major effort from the technological and chemical standpoints. Pre-existing hot cells were reconditioned and others specially built for these production operations. From the chemical standpoint, the development of extractive chromatography on the preparative scale has allowed the definition of simple processes. This type of process, initially developed for the treatment of Pu/Al targets, is ideal for the treatment of industrial wastes for their decontamination and for the production of 241Am

  12. Preparation of targets for nuclear chemistry experiments at DANCE

    In this paper, we describe the separation chemistry and electrodepositions conducted for the preparation of 241Am, 243Am and 233U targets used for cross-section measurements at DANCE. Thick, adherent deposits were prepared using molecular plating from isopropyl alcohol solutions. Improved yields and thicknesses were observed for 241Am electrodeposition after the material was purified using TRU resin from Eichrom. Similarly, 233U deposits were improved after purification with an anion exchange column in 9 M HBr followed by purification using UTEVA resin from Eichrom. (author)

  13. Research of vertical migration of radionuclides in the soil at testing 'Red forest' area

    Researches of vertical migration of Chernobyl origin radionuclides at testing 'Red forest' rea in 5-km ChNPP-zone were carried out. The γ- and β- spectrometer measurements of soil samples were carried out using the anticompton spectrometer and a beta spectrometer. Presence of 60Co, 134, 137Cs, 154,155Eu, 241Am to depth of 30 cm in all soil cuts was fixed. The sites with sod-low-podzol sandy soils on alluvial sands contain 137Cs, 90Sr and 241Am to depth of 60 cm. The presence 243Am and 243Cm was found in the top layers of soils at territory of testing area.

  14. Electrochemical oxidation of 243Am(III) in nitric acid by a terpyridyl-derivatized electrode

    Dares, C. J.; Lapides, A. M.; Mincher, B. J.; Meyer, T. J.

    2015-11-05

    A high surface area, tin-doped indium oxide electrode surface-derivatized with a terpyridine ligand has been applied to the oxidation of trivalent americium to Am(V) and Am(VI) in nitric acid. Potentials as low as 1.8 V vs. the saturated calomel electrode are used, 0.7 V lower than the 2.6 V potential for one-electron oxidation of Am(III) to Am(IV) in 1 M acid. This simple electrochemical procedure provides, for the first time, a method for accessing the higher oxidation states of Am in non-complexing media for developing the coordination chemistries of Am(V) and Am(VI) and, more importantly, for separation of americium from nuclear waste streams.

  15. Neutron-induced fission cross section measurement of 233U, 241Am and 243Am in the energy range 0.5 MeV En 20 MeV at nTOF at CERN

    Belloni, F. [Instituto Nazionale de Fisica Nucleare-Italy and CEA-France; Milazzo, P. M. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Calviani, M. [Laboratori Nazionali di Legnaro, Italy and CERN, Geneva, Switzerland; Colonna, N. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Mastinu, P. F. [INFN, Laboratori Nazionali di Legnaro, Italy; Abbondanno, U. [Instituto Nazionale de Fisica Nucleare, Trieste, Italy; Aerts, G. [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Alvarez, H. [University of Santiago de Compostela, Spain; Alvarez-Velarde, F. [Centro de Investigaciones Energeticas Medioambientales y Technol., Madrid, Spain; Andriamonje, S. [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Andrzejewski, J. [University of Lodz, Lodz, Poland; Assimakopoulos, P. A. [University of Ioannina, Greece; Audouin, L. [Centre National de la Recherche Scidntifique/IN2P3-IPN, Orsay, France; Badurek, G. [Vienna University of Technology, Austria; Barbagallo, M. [Instituto Nazionale di Fisica Nucleare, Bari, Italy; Baumann, P. [CNRS, Strasbourg, France; Becvar, F. [Charles University, Prague, Czech Republic; Berthoumieux, E. [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Calvino, F. [Universidad Politecnica de Madrid, Spain; Cerutti, F. [CERN, Geneva, Switzerland; Cano-Ott, D. [CIEMAT, Spain; Capote, R. [IAEA-Vienna, Austria and Universidad de Sevilla, Spain; Carrapico, C. [Instituto Tecnológico e Nuclear (ITN), Lisbon, Portugal; Carrillo de Albornoz, A. [Instituto Tecnológico e Nuclear (ITN), Lisbon, Portugal; Cennini, P. [CERN, Geneva, Switzerland; Chepel, V. [University of Ciombra, Portugal; Chiaveri, E. [CERN, Geneva, Switzerland; Cortes, G. [Universitat Politecnica de Catalunya, Barcelona, Spain; Couture, A. [University of Notre Dame, IN; Cox, J. [University of Notre Dame, IN; Dahlfors, M. [CERN, Geneva, Switzerland; David, S. [CNRS, Orsay, France; Dillmann, I. [Institut fur Kernphysik, Karlsruhe, Germany; Dolfini, R. [Universita di Pavia, Italy; Domingo-Pardo, C. [CSIC-Universidad de Valencia; Koehler, Paul [ORNL; The n_TOF Collaboration, [CERN, Geneva, Switzerland

    2012-01-01

    Neutron-induced fission cross section measurements of 233U, 243Am and 241Am relative to 235U have been carried out at the neutron time-of-flight facility n TOF at CERN. A fast ionization chamber has been employed. All samples were located in the same detector; therefore the studied elements and the reference 235U target are subject to the same neutron beam.

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

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

    1997-03-01

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

  17. Measurements of minor actinides cross sections for transmutation

    The existing reactors produce two kinds of nuclear waste: the fission products and heavy nuclei beyond uranium called minor actinides (Americium and Curium isotopes). Two options are considered: storage in deep geological site and/or transmutation by fast neutron induced fission. These studies involve many neutron data. Unfortunately, these data bases have still many shortcomings to achieve reliable results. The aim of these measurements is to update nuclear data and complement them. We have measured the fission cross section of 243Am (7370 y) in reference to the (n,p) elastic scattering to provide new data in a range of fast neutrons (1-8 MeV). A statistical model has been developed to describe the reaction 243Am (n,f). Moreover, the cross sections from the following reactions have been be extracted from these calculations: inelastic scattering 243Am (n,n') and radiative capture 243Am (n,γ) cross sections. The direct measurements of neutron cross sections are often a challenge considering the short half-lives of minor actinides. To overcome this problem, a surrogate method using transfer reactions has been used to study few isotopes of curium. The reactions 243Am (3He, d)244Cm, 243Am (3He, t)243Cm and 243Am (3He, α)242Am allowed to measure the fission probabilities of 243,244Cm and 242Am. The fission cross sections of 242,243Cm (162,9 d, 28,5 y) and 241Am (431 y) have been obtained by multiplying these fission probabilities by the calculated compound nuclear neutron cross section relative to each channel. For each measurement, an accurate assessment of the errors was realized through variance-covariance studies. For measurements of the reaction 243Am(n,f), the analysis of error correlations allowed to interpret the scope of these measures within the existing measurements. (author)

  18. Production of transplutonium elements. Overview of some national programmes

    In the last fifteen years programmes of production of transplutonium element isotopes have been well established or decided in various countries. These productions concern essentially 241Am, 243Am, 244Cm, 248Cm and 252Cf isotopes. In western world the most ambitious programme is developped by the USA in OAK RIDGE and SAVANNAH RIVER facilities for the production of transcurium elements, especially 252Cf; LOS ALAMOS, ROCKY FLATS and HANFORD facilities for 241Am production. Other western nations produced in the past or possess a permanent programme; for example kilogram amount of 241Am has been produced in RFA, while in France productions of 241Am, 243Am and 244Cm are run in routine. Various other countries are involved in the production of transplutonium isotopes but this correspond often to punctual productions. Informations related to the soviet's programme are scarce, but productions of mg quantities of transcurium elements are known. This paper gives 63 references about these programmes with special emphasis on the chemical processes

  19. Measurements of Fission Cross Sections of Actinides

    Wiescher, M; Cox, J; Dahlfors, M

    2002-01-01

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

  20. The OSMOSE Experimental Program for the qualification of integral cross sections of actinides

    The need of better nuclear data on minor actinides has been stressed by various organizations throughout the world. It especially deals with the studies on plutonium management and waste incineration in existing systems and transmutation of waste or Pu burning in future nuclear concepts. To address this issue, a Working Party of the OECD has been concerned with identifying these needs and has produced a detailed High Priority Request List for Nuclear Data. The first step in obtaining better nuclear data consists in measuring accurate integral data and comparing them to integrated energy dependent data: this comparison provides a direct assessment of the effect of deficiencies in the differential data. Several international programs have indicated a strong desire to obtain accurate integral reaction rate data for improving the major and minor actinides cross sections. Data on major actinides (i.e. 235U, 236U, 238U, 239Pu, 240Pu, 241Pu, 242Pu and 241Am) are reasonably well-known and available in the Evaluated Nuclear Data Files (JEFF, JENDL, ENDF-B). However information on the minor actinides (i.e. 232Th, 233U, 237Np, 238Pu, 242Am, 243Am, 242Cm, 243Cm, 244Cm, 245Cm, 246Cm and 247Cm) is less well-known and considered to be relatively poor in some cases, having to rely on model and extrapolation of few data points. In this framework, the ambitious OSMOSE program between the Commissariat a l'Energie Atomique (CEA), Electricite de France (EDF) and the U.S. Department of Energy (DOE) has been undertaken with the aim of measuring the integral absorption rate parameters of actinides in the MINERVE experimental facility located at the CEA Cadarache Research Center. The OSMOSE Program (Oscillation in Minerve of isOtopes in 'Eupraxic' Spectra) includes a complete analytical program associated with the experimental measurement program and aims at understanding and resolving potential discrepancies between calculated and measured values. The OSMOSE program began in 2005 and will

  1. The OSMOSE program for the qualification of integral cross sections of actinides: Preliminary results in a PWR-UOx spectrum

    The need for improved nuclear data for minor actinides has been stressed by various organizations throughout the world - especially for studies relating to plutonium management, waste incineration, transmutation of waste, and Pu burning in future nuclear concepts. Several international programs have indicated a strong desire to obtain accurate integral reaction rate data for improving the major and minor actinides cross sections. Data on major actinides (i.e. 235U, 236U, 238U, 239Pu, 240Pu, 241Pu, 242Pu and 241Am) are reasonably well-known and available in the Evaluated Nuclear Data Files (JEFF, JENDL, ENDF-BX However information on the minor actinides (i.e. 232Th, 233U, 237Np, 238Pu, 242Am, 243Am, 243Cm, 235Cm, 244Cm, 245Cm, 246Cm and 247Cm) is less well-known and considered to be relatively poor in some cases, having to rely on model and extrapolation of few data points. In this framework, the ambitious OSMOSE program between the Commissariat a l'Energie Atomique (CEA), Electricite de France (EDF) and the U.S. Dept. of Energy (DOE) has been undertaken with the aim of measuring the integral absorption rate parameters of actinides in the MINERVE experimental facility located at the CEA Cadarache Research Center. The OSMOSE Program (Oscillation in Minerve of isotopes in 'Eupraxic' Spectra) includes a complete analytical program associated with the experimental measurement program and aims at understanding and resolving potential discrepancies between calculated and measured values. In the OSMOSE program, the reactivity worth of samples containing separated actinides are measured in different neutron spectra using an oscillation technique with an overall expected accuracy better than 3%. Reactivity effects of less than 10 pcm (0.0001 or approximately 1.5 cents) are measured and compared with calibrations to determine the differential reactivity-worth of the individual samples. The first experimental results were obtained with a very good reproducibility in 2005 and

  2. R and D for actinide partitioning and recovery of valuables from high level waste using radiotracers

    In the context of growing world population with rapidly increasing energy needs and the threat of global warming due to CO2 emission (caused by fossil fuel burning), the nuclear energy may be an attractive option particularly in the developing countries. Recycling of fuel is a unique feature of nuclear power technology which makes it a favourable choice with respect to conservation of energy resources. Steady growth of global fuel reprocessing activities (6000 tHM/annum) implies a vital role of separation science in developing efficient procedures for the separation and purification of actinides and in devising safe procedures for the management of nuclear waste arising at different stages of the PUREX process. High Level Waste (HLW) comprising of the concentrate of the raffinate of the co-extraction cycle (with over 95% of the total radioactivity produced in the burn up process in reactor) need to be isolated from the biosphere. There is a consensus among the waste management technologists that the safest route to achieve this, is to deposit it in a stable geological formation after it's immobilization in suitable glass/Synroc matrix. It ensures that any risk from exposure due to accidental intervention or natural disturbance is minimized. Risk perception is essentially due to the large radiological toxicity associated with alpha emitters like 237Np, 241Am, 243Am and 245Cm. Isotopes of Pu (left unrecovered) present in HLW also contribute towards radiological toxicity. In view of the high cost involved and the need for continuous surveillance, several countries are considering modifying their reprocessing schemes to partition (isolate) long-lived actinides from HLW. Since the volume of the actinide oxides (which retain major fraction of the radio toxicity of HLW) is significantly lower as compared to the other metal oxides present in HLW, such an approach is expected to reduce the cost of immobilization as well as of disposal (in geological repository) and

  3. Average resonance parameters evaluation for actinides

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

    1997-03-01

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

  4. Evaluation of the contamination risk by 241AM from lightning rods disposed at uncontrolled garbage dump

    Radioactive lightning rods were manufactured in Brazil until 1989, when the licenses for using radioactive sources in these products were lifted by the national nuclear authority. Since then, radioactive devices have been replaced by Franklin type one and collected as radioactive waste. However, only 23 percent of the estimated total number of installed rods was delivered to Brazilian Nuclear Commission (Comissao Nacional de Energia Nuclear - CNEN). This situation is of concern as there is a possibility of the rods being discarded as domestic waste, considering that in Brazil, 63.6 percent of the municipal solid waste is disposed at uncontrolled garbage dump, according to Instituto Brasileiro de Geografia e Estatistica (IBGE) in 2000. In addition, americium, the most common employed radionuclide, is classified as a high toxicity element, when ingested or inhaled. In the present study, it was performed migration experiments of Am-241 by lysimeter system in order to evaluate the risk of contamination caused by radioactive lightning rods disposed as a common solid waste. Sources removed from lightning rods were placed inside lysimeters filled with organic waste, collected at the restaurant of Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, and the generated leachate was periodically analyzed to determine its characteristics such as pH, redox potential, solid content and concentration of the radioactive material. Microbial growth was also evaluated by counting the number of colony forming units. The equivalent dose to members of the public has been calculated considering the ingestion of drinking water, the most probable mode of exposure. The final result was about 145 times below the effective dose limit of 1 mSv.year-1 for members of the public, established by the International Commission on Radiological Protection (ICRP), demonstrating that the risk caused by lightning rods disposed at uncontrolled garbage dump is low. (author)

  5. Whole body counter calibration and determination of 241 Am body content

    Internal contamination of man by americium is relatively rare. It is possible at manipulations with americium in laboratory and at the production of AmBe neutron sources when safety measures are not fully kept. The most probable contamination route is inhalation when the radionuclide is manipulated in powder form.Americium is distributed in body to all tissues. According a modification of ICRP biokinetic model by USTUR (1994) based on Am measurements of exposed persons, fractions of initial deposition are 45 % in skeleton (elimination half life 50 years), 25 % in liver (2,5 y), 20 % in muscles (10 y) and 10% in other tissues (10 y). It is well known that concentration of americium is higher in trabecular bones (skull) as in cortical ones (long and short). It is deposited on a bone surface (both inner and outer), so the concentration in bones is dependent on a ratio of bone surface to bone volume.These facts are influencing reliable determination of Am in a body. The measurement geometry is chosen according the deposition of Am in a human body. The highest deposition is in skeleton and the second one in liver, lungs are the primary organ of contamination in case of inhalation. 1. Liver - in this case there are a lot of interferences from deposit in near soft tissues, lungs and variable thick of tissues between liver and detector. Calibration phantom is relatively simple to make - water solution of Am in a shaped flask. 2. Lungs - a large organ so the efficiency is relatively low and it is influenced by self-absorption in ribs and sternum, interfering is also the deposit in liver and soft tissues. Phantom preparation is problematic due to complex geometry and density of lungs. 3. Skeleton - ankle joint and bones of foot - the bone mass is large, the self-absorption in bones is a problem, preparation of a realistic calibration phantom is difficult due to complex geometry and need of manipulation with radioactive materials (e.g. plaster). 4. Skeleton - knee joints - the same problems as at ankle and interferences from muscles of thigh and calf. Phantom preparation is difficult due to complex geometry and need of manipulation with active materials (e.g. plaster). 5. Skeleton - skull - temporal bone - very complex geometry and various soft tissues (face muscles, ears) are interfering. 6. Skeleton - skull - roof of the neuro-cranium (parietal and frontal bones) - consists from flat bones with low variations in thickness. Thin overlapping tissue makes the self-absorption low. Preparation of phantom is much simpler as by other geometries. Thin (6 mm) phantom allow application of radionuclide water solution on both inner and outer surface and relatively homogeneous distribution in a phantom made from absorbing material, e.g. plaster.Use of real skull is complicated by a low ability of absorption of radionuclide solution. Our phantom is made from absorbent gauze and plaster what is adjusting the density and improving mechanical properties of the phantom.Simple and reproducible geometry enables simulation by a Monte Carlo code, enables to study influences of overlapping tissues with various thickness, influences of radionuclides present in overlapping tissues and in brain. (authors)

  6. A new evaluation of the cases of internal contamination with 241Am from the year 2001

    Widespread contamination occurred in the building in which radiation waste was handled. An occurrence of internal contamination of workers was also suspected. Therefore, workers were measured in vivo and bioassay was performed too. Estimation of committed effective dose had to be based on results of excretion analysis as irremovable surface contamination occurred on the skin and hair of workers, thus, influencing results of in vivo measurements. The results of bioassay of 7 workers were presented already before together with the evaluation of intakes and committed effective doses. At present time, the cases were re-evaluated using IMBA Professional Plus software. The main difference- in comparison with the previous evaluation are: the data sets with the excreted activity with urine and faeces are used simultaneously; the logarithmic-normal distribution of the data is assumed; uncertainty of the measured data is chosen according to IDEAS Guidelines; combination of acute and chronic intakes is used; aerosol absorption class in the lungs M and S and parameters for absorption found experimentally. Estimation of the intakes and committed effective doses were stepwise improved as more information from workplace were gained. Use of the sophisticated software IMBA, enabling simultaneous use of more data sets and enabling change of different input parameters made a significant improvement in the evaluation of experimental data. However, with exception of one case, the statistics of the fit was not good enough. Variation of more parameters in the model of americium biokinetics could be next step. However, it is not expected that it will lead to significant changes in the estimation of the doses. (authors)

  7. Target accuracy of MA nuclear data and progress in validation by post irradiation experiments with the fast reactor 'JOYO'

    This paper presents a discussion about the target accuracy of MA nuclear data for fast reactor cycle system development, as well as the validation work on those nuclear data by PIE analyses. The PIE analyses are in progress on fuels and MA samples (237Np, 241Am, 243Am, 244Cm) irradiated at the experimental fast reactor 'JOYO'. The analysis result on the first examined MA sample suggested the necessity of re-evaluation of the isomeric ratio for 241Am capture reaction both in ENDF/B-VI and in JENDL-3.3. The above result contributes to the uncertainty-reduction both of burnup reactivity loss and of gamma energy release from fuel assemblies. (author)

  8. Monte Carlo modeling of spallation targets containing uranium and americium

    Neutron production and transport in spallation targets made of uranium and americium are studied with a Geant4-based code MCADS (Monte Carlo model for Accelerator Driven Systems). A good agreement of MCADS results with experimental data on neutron- and proton-induced reactions on 241Am and 243Am nuclei allows to use this model for simulations with extended Am targets. It was demonstrated that MCADS model can be used for calculating the values of critical mass for 233,235U, 237Np, 239Pu and 241Am. Several geometry options and material compositions (U, U + Am, Am, Am2O3) are considered for spallation targets to be used in Accelerator Driven Systems. All considered options operate as deep subcritical targets having neutron multiplication factor of k∼0.5. It is found that more than 4 kg of Am can be burned in one spallation target during the first year of operation

  9. Preparation of americium targets for nuclear chemistry experiments at DANCE

    Using 1 gram of 241Am from LANL stocks, the purification steps required to obtain a solution of 241Am from the original material are described. Part of the purified solution was submitted for purity analysis by mass spectrometry, radiochemistry and trace metals analysis. The impurities were expected to be 239Pu and 237Np. A second fraction of this material was used for electroplating three samples onto titanium disks that were suitable for insertion into an instrument package to be placed into the DANCE detector. The purification methods used, the electroplating setup and the solutions to various problems that were encountered in making these targets are discussed. The analytical results are discussed as well as the yields from the electrodeposition process. Comparison of these yields with those from similar experiments utilizing 235U and 243Am are also discussed. (author)

  10. Results of the Excreta Bioassay Quality Control Program for April 1, 2009 through March 31, 2010

    Antonio, Cheryl L.

    2012-07-19

    A total of 58 urine samples and 10 fecal samples were submitted during the report period (April 1, 2009 through March 31, 2010) to General Engineering Laboratories, South Carolina by the Hanford Internal Dosimetry Program (IDP) to check the accuracy, precision, and detection levels of their analyses. Urine analyses for Sr, 238Pu, 239Pu, 241Am, 243Am 235U, 238U, elemental uranium and fecal analyses for 241Am, 238Pu and 239Pu were tested this year as well as four tissue samples for 238Pu, 239Pu, 241Am and 241Pu. The number of QC urine samples submitted during the report period represented 1.3% of the total samples submitted. In addition to the samples provided by IDP, GEL was also required to conduct their own QC program, and submit the results of analyses to IDP. About 33% of the analyses processed by GEL during the third year of this contract were quality control samples. GEL tested the performance of 21 radioisotopes, all of which met or exceeded the specifications in the Statement of Work within statistical uncertainty (Table 4).

  11. VERTICAL MIGRATION OF RADIONUCLIDES IN THE VICINITY OF THE CHERNOBYL CONFINEMENT SHELTER

    Farfan, E.; Jannik, T.; Marra, J.

    2011-10-01

    Studies on vertical migration of Chernobyl-origin radionuclides in the 5-km zone of the Chernobyl Nuclear Power Plant (ChNPP) in the area of the Red Forest experimental site were completed. Measurements were made by gamma spectrometric methods using high purity germanium (HPGe) detectors with beryllium windows. Alpha-emitting isotopes of plutonium were determined by the measurement of the x-rays from their uranium progeny. The presence of {sup 60}Co, {sup 134,137}Cs, {sup 154,155}Eu, and {sup 241}Am in all soil layers down to a depth of 30 cm was observed. The presence of {sup 137}Cs and {sup 241}Am were noted in the area containing automorphous soils to a depth of 60 cm. In addition, the upper soil layers at the test site were found to contain {sup 243}Am and {sup 243}Cm. Over the past ten years, the {sup 241}Am/{sup 137}Cs ratio in soil at the experimental site has increased by a factor of 3.4, nearly twice as much as would be predicted based solely on radioactive decay. This may be due to 'fresh' fallout emanating from the ChNPP Confinement Shelter.

  12. Migration of the radionuclides 99Tc, 237Np, 238Pu and 241Am in the caprock of the Gorleben repository

    31 different combinations of sediments with groundwaters (sediment-groundwater-systems) formed the basis of the experiments to determine sorption data and sorption mechanisms of radionuclides in selected acquifer systems with loose rock samples taken from shafts 1 and 2. The waters were selected on the basis of pore water analyses. For cohesive materials from which no pore water could be extracted, groundwaters from the horizon below and above were chosen. (orig.)

  13. Determination of vanadium, manganese and tungsten in steels with an 241 Am-Be isotopic neutron source

    A non-destructive neutron activation method was developed for determination of vanadium, manganese, and tungsten in alloy-steel, with the aid of an Am-Be 1,85x1011Bq(5Ci) isotopic neutron source, employing NaI (T1) detector well type 2x2 in. The 51V (n,γ) 52V, 55Mn (n,γ) 56Mn, and 186W (n,γ) 187W nuclear reactions are induced in steel samples subject to activation by thermal neutron. After irradiation, the activity of the samples was measured by γ-spectrometry under the 1434 KeV 52V, 847KeV 56Mn, and 686 KeV 187W photopeaks. Possible interferences due to other radionuclides activity were investigated by determining the 52V, 56Mn, and 187W half-lifes. The time of analysis for vanadium determination was 11 min, with 1,5% of precision and 3,4% of average absolute deviation. The time of analysis for manganese determination was 22,8 min with 4,0% of precision and 3,4% of average absolute deviation. The time of analysis for tungsten determination was 44,62 min with 3,8% of precision and 3,1% of average absolute deviation. The activation analysis method is adequated for steel quality control in industry. (Author)

  14. Concentrations of 239,240Pu and 241Am of marine products in coastal waters of Ibaraki

    More than 200 samples of marine products have been collected and analyzed for plutonium and almost 100 samples for americium around Hitachi, Tokai and Oarai in the pacific coast of Ibaraki prefecture. The data have shown that the concentration factor (CF) values for plutonium were 330 for bivalve, 770 for abalone (muscle) and 610 for brown algae. For americium, the CF was calculated as 2400 for bivalve, 1000 for abalone (muscle) and 420 for brown algae. (author)

  15. Plutonium, 241Am and 137Cs ratios, inventories and vertical profiles in Washington and Oregon continental shelf sediments

    Beasley, T. M.; Carpenter, R.; Jennings, C. D.

    1982-10-01

    Continental shelf sediments from nine locations off Washington and Oregon have 239,240Pu inventories which average 8.0 ± 2.6 mCi/km 2. The Columbia River and seawaters advecting over the shelf supply Pu which is removed to underlying sediments, principally through scavenging by inorganic paniculate matter. Mass balance calculations argue that less than 20 percent of the advected Pu need be scavenged from the water column to balance river input and total shelf sediment inventories. The percentage of the Pu removed through scavenging is consistent with observed participate concentrations in shelf waters and published sediment/water distribution coefficients. No marked separation of Pu from 137Cs is observed with depth in Pacific shelf sediments as has been reported in Atlantic coastal sediments. This interocean distinctness can be explained by differences in particle mixing and downward diffusion of Cs in sediments of varying porosities. The transuranic inventories and Pu/Cs ratios in the Pacific sediments do not support the hypothesis of Livingston and Bowen that Pu is remobilized within the sediment column by 'complexone' formation with (principally) organic substances. Excess 210Pb/ 239,240Pu inventory ratios in eight representative cores from the Washington shelf average 100 ± 19, even though absolute values of both inventories vary by much larger factors. This reasonably constant ratio, for a given water depth, permits estimation of total Pu inventories and prediction of sites of unusual Pu accumulation from data on the more easily measured natural radionuclide.

  16. Prompt neutron multiplicities for the transplutonium nuclides

    The direct determination of the average prompt neutron emission values is reviewed, and a method of comparing different sites of neutron emission multiplicity distribution values is described. Measured and recommended values are tabulated for these nuclides: 241Am, 242Am, 242Cm, 243Cm, 244Cm, 246Cm, 247Cm, 248Cm, 250Cm, 245Cm, 249Bk, 246Cf, 249Cf, 250Cf, 252Cf, 254Cf, 251Cf, 253Es, 254Es, 244Fm, 246Fm, 255Fm, 252No, 254Fm, 256Fm, 257Fm. 59 refs., 24 tabs

  17. MANTRA: An Integral Reactor Physics Experiment to Infer Actinide Capture Cross-sections from Thorium to Californium with Accelerator Mass Spectrometry

    G. Youinou; C. McGrath; G. Imel; M. Paul; R. Pardo; F. Kondev; M. Salvatores; G. Palmiotti

    2011-08-01

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectrometry technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am, 244Cm and 248Cm.

  18. Combined procedure using radiochemical separation of plutonium, americium and uranium radionuclides for alpha-spectrometry

    Radiochemical separation of Pu, Am and U was tested from synthetic solutions and evaporator concentrate samples from nuclear power plants for isolation of each of them for alpha-spectrometry analysis. The separation was performed by anion-exchange chromatography, extraction chromatography, using TRU resin, and precipitation techniques. The aim of the study was to develop a sensitive analytical procedure for the sequential determination of 242Pu, 238Pu, 239+240Pu, 241Am and 235,238U in radioactive wastes. 238Pu, 242Pu, 243Am and 232U were used as tracers. The measurements of α emitting radionuclides were performed by semiconductor detector that is used especially when spectrometric information is needed. For synthetic solutions the chemical recovery was based on associated iron concentration and was about 93%. (author)

  19. Neutron resonance transmission analysis of reactor spent fuel assemblies

    A method called Neutron Resonance Transmission Analysis (NRTA) is under study which would use a pulsed neutron beam for nondestructive isotopic assay of a complete spent fuel assembly. Neutrons removed from the collimated beam by absorption or scattering in the resonances of the various isotopes in the spent fuel appear as dips in the neutron transmission. The method is completely insensitive to matrix materials such as oxide, fuel cladding, and other structural members. Measurements on spent fuel buttons using the NBS linac as a pulsed neutron source demonstrate a high accuracy capability for the isotopes 234235236238U, 239240241242Pu, 241Am, 243Am, and several fission products. The NRTA method offers high speed and modest operational cost, and it can be implemented with commercially available medical or radiographic γ-ray generators adapted for neutron production. (Auth.)

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

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

  1. AN INTEGRAL REACTOR PHYSICS EXPERIMENT TO INFER ACTINIDE CAPTURE CROSS-SECTIONS FROM THORIUM TO CALIFORNIUM WITH ACCELERATOR MASS SPECTROMETRY

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor (ATR) at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectroscopy (AMS) technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am and 248Cm.

  2. MANTRA: An Integral Reactor Physics Experiment to Infer Actinide Capture Cross-sections from Thorium to Californium with Accelerator Mass Spectrometry

    The principle of the proposed experiment is to irradiate very pure actinide samples in the Advanced Test Reactor at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. This approach has been used in the past and the novelty of this experiment is that the atom densities of the different transmutation products will be determined using the Accelerator Mass Spectrometry technique at the ATLAS facility located at ANL. It is currently planned to irradiate the following isotopes: 232Th, 235U, 236U, 238U, 237Np, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 243Am, 244Cm and 248Cm.

  3. WWER-1000 spent fuel nuclide inventory at the Kozloduy NPP

    This paper contains a presentation and discussion of selected isotope inventory results for different types of WWER-1000 spent fuel assemblies. Nuclide inventory calculations of spent fuel assemblies at the Kozloduy NPP are routinely performed using the SCALE 4.4a computer code system. Besides the standard 17x17 ORIGEN-S library, a specific library developed at the Kozloduy NPP for each different fuel type at typical irradiation conditions is used. The evaluated concentrations of the most important isotopes - 235U, 236U, 238U, 239Pu, 240Pu, 241Pu, 242Pu - depending on burnup, are compared with fuel supplier data and with data calculated using the HELIOS-1.5 lattice code. The buildup of some other isotopes (237Np, 241Am, 243Am) is presented, too. (authors)

  4. WWER-1000 spent fuel nuclide inventory at the Kozloduy NPP

    This paper contains a presentation and discussion of selected isotope inventory results for different types of WWER-1000 spent fuel assemblies. Nuclide inventory calculations of spent fuel assemblies at Kozloduy NPP are routinely performed using the SCALE 4.4a computer code system. Besides the standard 17x17 ORIGEN-S library, a specific library developed at the Kozloduy NPP for each different fuel type at typical irradiation conditions is used. The evaluated concentrations of the most important isotopes-235U, 236U, 238U, 239Pu, 240Pu, 241Pu, 242Pu-depending on burnup, are compared with fuel supplier data and with data calculated using the HELIOS-1.5 lattice code. The buildup of some other isotopes (237Np, 241Am, 243Am) is presented, too (Authors)

  5. Fast neutron capture in actinide isotopes: recent results from Karlsruhe

    Capture gamma-ray spectra of 241Am, 240Pu, 242Pu 238U and 197Au were calculated in the framework of the spherical optical model and the statistical model. These spectra were used to correct experimental data for the capture cross sections of 240242Pu and 241Am from relative measurements using a Moxon Rae-detector with graphite converter and 197Au as well as 238U as standards. This correction is required to take into account that the detector efficiency is not exactly proportional to gamma-ray energy. The resulting correction factors proved to be negligible for measurements relative to 238U, whereas they are approx. 3% if gold is used as a standard. The capture cross section of 243Am has been measured in the energy range 10 to 250 keV using kinematically collimated neutrons from the 7Li(p,n) and T(p,n) reaction. The samples are positioned at flight paths of 5 to 7 cm and gold was used as a standard. Capture events were detected by two Moxon-Rae detectors with graphite and bismuth-graphite converters shielded by 0.5 to 2 cm of lead. Fission events were detected by a NE213 liquid scintillator. The present status of the experiment and some preliminary results will be presented

  6. Results of The Excreta Bioassay Quality Control Program For April 1, 2010 Through March 31, 2011

    Antonio, Cheryl L.

    2012-07-19

    A total of 76 urine samples and 10 spiked fecal samples were submitted during the report period (April 1, 2010 through March 31, 2011) to GEL Laboratories, LLC in South Carolina by the Hanford Internal Dosimetry Program (IDP) to check the accuracy, precision, and detection levels of their analyses. Urine analyses for 14C, Sr, for 238Pu, 239Pu, 241Am, 243Am, 235U, 238U, 238U-mass and fecal analyses for 241Am, 238Pu and 239Pu were tested this year. The number of QC urine samples submitted during the report period represented 1.1% of the total samples submitted. In addition to the samples provided by IDP, GEL was also required to conduct their own QC program, and submit the results of analyses to IDP. About 31% of the analyses processed by GEL during the first year of contract 112512 were quality control samples. GEL tested the performance of 23 radioisotopes, all of which met or exceeded the specifications in the Statement of Work within statistical uncertainty except the slightly elevated relative bias for 243,244Cm (Table 4).

  7. Results of The Excreta Bioassay Quality Control Program For April 1, 2008 through March 31, 2009

    Antonio, Cheryl L.

    2010-06-01

    A total of 62 urine samples and 6 spiked fecal samples were submitted during the report period (April 1, 2008 through March 31, 2009) to General Engineering Laboratories, South Carolina by the Hanford Internal Dosimetry Program (IDP) to check the accuracy, precision, and detection levels of their analyses. Urine analyses for Sr, 238Pu, 239Pu, 241Am, 243Am 235U, 238U, elemental uranium and fecal analyses for 241Am, 238Pu and 239Pu were tested this year. The number of QC urine samples submitted during the report period represented 1.3% of the total samples submitted. In addition to the samples provided by IDP, GEL was also required to conduct their own QC program, and submit the results of analyses to IDP. About 34% of the analyses processed by GEL during the third year of this contract were quality control samples. GEL tested the performance of 21 radioisotopes, all of which met or exceeded the specifications in the Statement of Work within statistical uncertainty. IDP concluded that GEL was performing well for all analyses tested, and concerns identified earlier were satisfactorily resolved (see section on Follow-up on Concerns During the Fourth Contract Year).

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

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

  9. Post irradiation examination of irradiated americium oxide and uranium dioxide in magnesium aluminate spinel

    To study MgAl2O4 spinel as inert matrix material for the transmutation of minor actinides, two capsules were irradiated at the high flux reactor in Petten, containing 12.5 wt% micro-dispersed 241AmOx in spinel and 25 wt% micro-dispersed enriched UO2 in spinel. During irradiation, the initially present 241Am was converted for 99.8% to fission products (50%), plutonium (30%), curium (16%) and 243Am (4%). The UO2 spinel target experienced a burn-up of 32% fission per initial metal atom. The post irradiation examination of the AmOx inert matrix target showed swelling of 27 vol.%, and a gas release of 48% for He and 16% for Xe and Kr. The UO2 inert matrix target also showed a large volumetric swelling of 11%, directed mainly radially. Ceramography on the UO2 inert matrix target revealed a complete restructuring of the spinel grains upon irradiation and the absence of porosity, suggesting that amorphisation is the main cause of the swelling

  10. Post irradiation examination of irradiated americium oxide and uranium dioxide in magnesium aluminate spinel

    Klaassen, F. C.; Bakker, K.; Schram, R. P. C.; Klein Meulekamp, R.; Conrad, R.; Somers, J.; Konings, R. J. M.

    2003-06-01

    To study MgAl 2O 4 spinel as inert matrix material for the transmutation of minor actinides, two capsules were irradiated at the high flux reactor in Petten, containing 12.5 wt% micro-dispersed 241AmO x in spinel and 25 wt% micro-dispersed enriched UO 2 in spinel. During irradiation, the initially present 241Am was converted for 99.8% to fission products (50%), plutonium (30%), curium (16%) and 243Am (4%). The UO 2 spinel target experienced a burn-up of 32% fission per initial metal atom. The post irradiation examination of the AmO x inert matrix target showed swelling of 27 vol.%, and a gas release of 48% for He and 16% for Xe and Kr. The UO 2 inert matrix target also showed a large volumetric swelling of 11%, directed mainly radially. Ceramography on the UO 2 inert matrix target revealed a complete restructuring of the spinel grains upon irradiation and the absence of porosity, suggesting that amorphisation is the main cause of the swelling.

  11. Post irradiation examination of irradiated americium oxide and uranium dioxide in magnesium aluminate spinel

    Klaassen, F.C. E-mail: klaassen@nrg-nl.com; Bakker, K.; Schram, R.P.C.; Klein Meulekamp, R.; Conrad, R.; Somers, J.; Konings, R.J.M

    2003-06-01

    To study MgAl{sub 2}O{sub 4} spinel as inert matrix material for the transmutation of minor actinides, two capsules were irradiated at the high flux reactor in Petten, containing 12.5 wt% micro-dispersed {sup 241}AmO{sub x} in spinel and 25 wt% micro-dispersed enriched UO{sub 2} in spinel. During irradiation, the initially present {sup 241}Am was converted for 99.8% to fission products (50%), plutonium (30%), curium (16%) and {sup 243}Am (4%). The UO{sub 2} spinel target experienced a burn-up of 32% fission per initial metal atom. The post irradiation examination of the AmO{sub x} inert matrix target showed swelling of 27 vol.%, and a gas release of 48% for He and 16% for Xe and Kr. The UO{sub 2} inert matrix target also showed a large volumetric swelling of 11%, directed mainly radially. Ceramography on the UO{sub 2} inert matrix target revealed a complete restructuring of the spinel grains upon irradiation and the absence of porosity, suggesting that amorphisation is the main cause of the swelling.

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

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

  13. Sensitivity analysis for actinide production and depletion in fast reactors

    In sensitivity analysis of the actinide production and depletion in fast reactors, a mathematical method of calculating sensitivity coefficients is improved and simplified by combining the time-dependent generalized perturbation technique with the eigenvalue method. Numerical calculations show that the eigenvalue method is well applicable in solving the nuclide chain equation and its adjoint equation and the cylic chains in the decay scheme of the actinides can be interpreted by means of complex eigenvalues. The sensitivity coefficients of actinide production and depletion in a 1000 MWe fast reactor are strongly dependent on the type of Pu fuel used, i.e. Pu fuel from BWR or Pu fuel from the blanket of FBR. The sensitivity coefficients due to variations of capture cross sections, σsub(n,2n) of 238U, lambda sub(β) of 241Pu and lambda sub(α) of 242Cm are especially large. Sensitivity analyses for the 1000 MWe fast reactors show that higher priorily should be given to decay constants of 241Pu and 242Cm, capture cross sections of 237Np, 241Am, 243Am and 242Pu, and fission cross sections of 237Np, 242Pu, 241Am and sup(242m)Am. (author)

  14. Biological pathways and chemical behavior of plutonium and other actinides in the environment

    The principal long-lived actinide elements that may enter the environment from either U or Pu fuel cycles are Pu, Am, Cm, and Np. Approximately 25% of the alpha activity estimated to be released to the atmosphere from the LMFBR fuel cycle will be contributed by 241Am, 242Cm, and 244Cm. The balance of the alpha activity will come from Pu isotopes. Activities of 242Cm, 244Cm, 241Am, 243Am, and 237Np in waste may exceed concentrations of Pu isotopes in waste after various periods of decay. Thorium and uranium isotopes may also be released by operations of the thorium fuel cycle. Environmental actinides are discussed under the following headings: sources of man-made actinide elements; pathways of exposure; environmental chemistry of actinides; uptake of actinides by plants; distribution of actinides in components of White Oak Lake; entry of actinides into terrestrial food chains; relationship between chemical behavior and uptake of actinides by organisms; and behavior of Pu in freshwater and marine food chains

  15. Safe handling of kilogram amounts of fuel-grade plutonium and of gram amounts of plutonium-238, americium-241 and curium-244

    During the past 10 years about 600 glove-boxes have been installed at the Institute for Transuranium Elements at Karlsruhe. About 80% of these glove-boxes have been designed and equipped for handling 100-g to 1-kg amounts of 239Pu containing 8-12% 240Pu (low-exposure plutonium). A small proportion of the glove-boxes is equipped with additional shielding in the form of lead sheet or lead glass for work with recycled plutonium. In these glove-boxes gram-amounts of 241Am have also been handled for preparation of Al-Am targets using tongs and additional shielding inside the glove-boxes themselves. Water- and lead-shielded glove-boxes equipped with telemanipulators have been installed for routine work with gram-amounts of 241Am, 243Am and 244Cm. A prediction of the expected radiation dose for the personnel is difficult and only valid for a preparation procedure with well-defined preparation steps, owing to the fact that gamma dose-rates depend strongly upon proximity and source seize. Gamma radiation dose measurements during non-routine work for 241Am target preparation showed that handling of gram amounts leads to a rather high irradiation dose for the personnel, despite lead or steel glove-box shielding and shielding within the glove-boxes. A direct glove-hand to americium contact must be avoided. For all glove-handling of materials with gamma radiation an irradiation control of the forearms of the personnel by, for example, thermoluminescence dosimeters is necessary. Routine handling of americium and curium should be executed with master-slave equipment behind neutron and gamma shielding. (author)

  16. Development of fission micro-chambers for nuclear waste incineration studies

    The incineration of transuranic elements by neutron induced fission is a very promising way to reduce long-term radiotoxicity of nuclear waste. The Mini-Inca aims to outline the ideal physical conditions to transmute minor actinides, mainly 241-243Am, 237Np and 244-245Cm. For some actinides there are large discrepancies of neutron cross sections taken from different evaluated nuclear data libraries. These cross sections play a dominant role in transmutation systems. For instance, a factor 20 was pointed out for the 242gsAm thermal neutron capture cross section from JEF-2.2 (5500 barns) and ENDF-B/VI (250 barns) libraries. Computer simulations can lead to controversial results depending on the nuclear data library that was used. To measure the incineration rate of minor actinides, and to provide an unambiguous experimental reference, fission micro-chambers are of great interest. (author)

  17. Actinide targets for the synthesis of super-heavy elements

    Roberto, J. B.; Alexander, C. W.; Boll, R. A.; Burns, J. D.; Ezold, J. G.; Felker, L. K.; Hogle, S. L.; Rykaczewski, K. P.

    2015-12-01

    Since 2000, six new super-heavy elements with atomic numbers 113 through 118 have been synthesized in hot fusion reactions of 48Ca beams on actinide targets. These target materials, including 242Pu, 244Pu, 243Am, 245Cm, 248Cm, 249Cf, and 249Bk, are available in very limited quantities and require specialized production and processing facilities resident in only a few research centers worldwide. This report describes the production and chemical processing of heavy actinide materials for super-heavy element research, current availabilities of these materials, and related target fabrication techniques. The impact of actinide materials in super-heavy element discovery is reviewed, and strategies for enhancing the production of rare actinides including 249Bk, 251Cf, and 254Es are described.

  18. Fission cross-section measurements on 233U and minor actinides at the CERN n-TOF facility

    Neutron-induced fission cross-sections of minor actinides have been measured at the white neutron source n-TOF at CERN, Geneva. The studied isotopes include 233U, interesting for Th/U based nuclear fuel cycles, 241,243Am and 245Cm, relevant for transmutation and waste reduction studies in new generation fast reactors (Gen-IV) or Accelerator Driven Systems. The measurements take advantage of the unique features of the n-TOF facility, namely the wide energy range, the high instantaneous neutron flux and the low background. Results for the involved isotopes are reported from ∼30 meV to around 1 MeV neutron energy. The measurements have been performed with a dedicated Fission Ionization Chamber (FIC), relative to the standard cross-section of the 235U fission reaction, measured simultaneously with the same detector. Results are here reported. (authors)

  19. 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)

  20. Comparison among the rice bark in the raw and active forms in the removal of 241Am and 137Cs from liquid radioactive wastes

    New techniques involving treatment of radioactive wastes which associate simplicity and low cost have been directed the attention for the bio sorption, which is a process were solid vegetable or micro-organism for the retention, removing, or recovering of heavy metals from a liquid environment. This study evaluated the capacity of a bio sorbent to remove Am-241 and Cs-137 from liquid radioactive waste. The chosen material was the rice bark employed in the raw or activated forms. The obtained results suggest that the bio sorption, with the activated rice bark, can be a viable technique for the treatment of liquid radioactive wastes containing Am-241 and Cs-137 present in liquid radioactive wastes

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

    Adam, Jindřich

    2007-01-01

    Roč. 68, č. 2 (2007), s. 201-212. ISSN 0304-4289 R&D Projects: GA MŠk 1P04LA213 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutro production Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.383, year: 2007

  2. Distribution of sup 137 Cs, sup 90 Sr, sup 238 Pu, sup 239 Pu, sup 241 Am and sup 244 Cm in Pond B, Savannah River Site

    Whicker, F.W. (Colorado State Univ., Fort Collins, CO (USA)); Pinder, J.E. III; Bowling, J.W. (Savannah River Ecology Lab., Aiken, SC (USA)); Alberts, J.J. (Georgia Univ., Sapelo Island, GA (USA). Marine Inst.); Brisbin, I.L. Jr. (Savannah River Ecology Lab., Aiken, SC (USA))

    1989-05-01

    The gradual senescence of present-day operating nuclear facilities, and resultant contamination of aquatic and terrestrial ecosystems, emphasize the importance of understanding the behavior of radionuclides in the environment. Observations and deductions concerning mechanisms of radionuclide transport can contribute significantly to knowledge of fundamental ecological processes. This study emphasized the ecosystem-level distribution of several long-lived radionuclides in an abandoned reactor cooling impoundment after a twenty year period of chemical and biological equilibration. 90 refs., 14 figs., 5 tabs.

  3. Artificial radioactivity and marine environment. Study of 238Pu, 239Pu+240Pu, 241Pu and 241Am in the Mediterranean sea

    This paper is in two parts. Part one is about the methods for analyzing transuranium elements particularly the development of an analytical process for plutonium and for perfecting an Americium analyzing method, capable of treating samples of 200 litres of sea water, 100 grams of sediment and 100 grams of biological matter. Part two concerns the in situ determinations carried out within the scope of the study on the distribution and behaviour of transuranium elements in the Mediterranean sea. The high sea studies concerned the effects of atmospheric fall out and the vertical distribution of Pu and Am. Studies along the coasts enabled a quantitative study to be made of the contribution of rivers to the Mediterranean and to study the distribution of Pu along the French Mediterranean coast line

  4. 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)

  5. Monte Carlo calculations on transmutation of transuranic nuclear waste isotopes using spallation neutrons. Difference of lead and graphite moderators

    Transmutation rates of 239Pu and some minor actinides (237Np, 241Am, 245Cm and 246Cm), in two accelerator driven systems (ADS) with lead or graphite moderating environments, were calculated using the LAHET code system. The ADS that were used had a large volume (∼ 30 m3) and contained no fissile material, except for a small amount of fissionable waste nuclei that existed in some cases. Calculations were performed at incident proton energy of 1.5 GeV and spallation target was lead. Also breeding rates of 239Pu and 233U as well as the transmutation rates of two long-lived fission products 99Tc and 129I were calculated at different locations in the moderator. It is shown that an ADS with graphite moderator is a much more effective transmuter than that with lead moderator

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

    It is well known that ammunition containing depleted uranium (DU) was used by NATO during the Balkan conflict. To evaluate the origin of DU (the enrichment of natural uranium or the reprocessing of spent nuclear fuel) it is necessary to directly detect the presence of activation products (236U, 239Pu, 240Pu, 241Am, and 237Np) in the ammunition. In this work the analysis of actinides by α-spectrometry was compared with that by inductively coupled plasma mass spectrometry (ICP-MS) after selective separation of ultratraces of transuranium elements from the uranium matrix. 242Pu and 243Am were added to calculate the chemical yield. Plutonium was separated from uranium by extraction chromatography, using tri-n-octylamine (TNOA), with a decontamination factor higher than 106; after elution plutonium was determined by ICP-MS (239Pu and 240Pu) and α-spectrometry (239+240Pu) after electroplating. The concentration of Pu in two DU penetrator samples was 7 x 10-12 g g-1 and 2 x 10-11 g g-1. The 240Pu/239Pu isotope ratio in one penetrator sample (0.12±0.04) was significantly lower than the 240Pu/239Pu ratios found in two soil samples from Kosovo (0.35±0.10 and 0.27±0.07). 241Am was separated by extraction chromatography, using di(2-ethylhexyl)phosphoric acid (HDEHP), with a decontamination factor as high as 107. The concentration of 241Am in the penetrator samples was 2.7 x 10-14 g g-1 and -15 g g-1. In addition 237Np was detected at ultratrace levels. In general, ICP-MS and α-spectrometry results were in good agreement.The presence of anthropogenic radionuclides (236U, 239Pu,240Pu, 241Am, and 237Np) in the penetrators indicates that at least part of the uranium originated from the reprocessing of nuclear fuel. Because the concentrations of radionuclides are very low, their radiotoxicological effect is negligible. (orig.)

  7. Comparison among the rice bark in the raw and active forms in the removal of {sup 241}Am and {sup 137}Cs from liquid radioactive wastes; Comparacao entre a casca de arroz nas formas brutas e ativada na remocao de {sup 241}Am e {sup 137}Cs de rejeitos radioativos liquidos

    Ferreira, Rafael V.P.; Lima, Josenilson B. de; Bellini, Maria Helena; Sakata, Solange Kazumi; Marumo, Julio Takehiro, E-mail: rpadua@ipen.b, E-mail: sksakata@ipen.b, E-mail: jblima@ipen.b, E-mail: mbmarumo@ipen.b, E-mail: jtmarumo@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-10-26

    New techniques involving treatment of radioactive wastes which associate simplicity and low cost have been directed the attention for the bio sorption, which is a process were solid vegetable or micro-organism for the retention, removing, or recovering of heavy metals from a liquid environment. This study evaluated the capacity of a bio sorbent to remove Am-241 and Cs-137 from liquid radioactive waste. The chosen material was the rice bark employed in the raw or activated forms. The obtained results suggest that the bio sorption, with the activated rice bark, can be a viable technique for the treatment of liquid radioactive wastes containing Am-241 and Cs-137 present in liquid radioactive wastes

  8. Investigation of neutronic behavior in a CANDU reactor with different (Am, Th, 235U)O2 fuel matrixes

    Recently thorium-based fuel matrixes are taken into consideration for nuclear waste incineration because of thorium proliferation resistance feature moreover its breeding or convertor ability in both thermal and fast reactors. In this work, neutronic influences of adding Am to (Th-235U)O2 on effective delayed neutron fraction, reactivity coefficients and burn up of a fed CANDU core has been studied using MCNPX 2.6.0 computational code. Different atom fractions of Am have been introduced in the fuel matrix to evaluate its effects on neutronic parameters of the modeled core. The computational data show that adding 2% atom fraction of Am to thorium-based fuel matrix won't noticeably change reactivity coefficients in comparison with the fuel matrix containing 1% atom fraction of Am. The use of 2% atom fraction of Am resulted in a higher delayed neutron fraction. According to the obtained data, 32.85 GWd burn up of the higher Americium-containing fuel matrix resulted in 55.2%, 26.5%, 41.9% and 2.14% depletion of 241Am, 243Am, 235U and 232Th respectively. 132.8 kg of 233U fissile element is produced after the burn up time and the nuclear core multiplication factor increases in rate of 2390 pcm. The less americium-containing fuel matrix resulted in higher depletion of 241/243Am, 235U and 232Th while the nuclear core effective multiplication factor increases in rate of 5630 pcm after the burn up time with 9.8 kg additional 233U production.

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

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

  10. Behavior of actinides in the Integral Fast Reactor fuel cycle

    Courtney, J.C. [Louisiana State Univ., Baton Rouge, LA (United States). Nuclear Science Center; Lineberry, M.J. [Argonne National Lab., Idaho Falls, ID (United States). Technology Development Div.

    1994-06-01

    The Integral Fast Reactor (IFR) under development by Argonne National Laboratory uses metallic fuels instead of ceramics. This allows electrorefining of spent fuels and presents opportunities for recycling minor actinide elements. Four minor actinides ({sup 237}Np, {sup 240}Pu, {sup 241}Am, and {sup 243}Am) determine the waste storage requirements of spent fuel from all types of fission reactors. These nuclides behave the same as uranium and other plutonium isotopes in electrorefining, so they can be recycled back to the reactor without elaborate chemical processing. An experiment has been designed to demonstrate the effectiveness of the high-energy neutron spectra of the IFR in consuming these four nuclides and plutonium. Eighteen sets of seven actinide and five light metal targets have been selected for ten day exposure in the Experimental Breeder Reactor-2 which serves as a prototype of the IFR. Post-irradiation analyses of the exposed targets by gamma, alpha, and mass spectroscopy are used to determine nuclear reaction-rates and neutron spectra. These experimental data increase the authors` confidence in their ability to predict reaction rates in candidate IFR designs using a variety of neutron transport and diffusion programs.

  11. EMP Attachment 1 DOE-SC PNNL Site Sampling and Analysis Plan

    Meier, Kirsten M.

    2011-11-10

    This Sampling and Analysis Plan (SAP) is written for the radiological environmental air surveillance program for the DOE-SC PNNL Site, Richland Washington. It provides the requirements for planning sampling events, and the requirements imposed on the analytical laboratory analyzing the air samples. The actual air sampling process is in procedure EPRP-AIR-029. The rationale for analyte selection, media, and sampling site location has been vetted through the data quality objectives (DQO) process (Barnett et al. 2010). The results from the DQO process have been reviewed and approved by the Washington State Department of Health. The DQO process (Barnett et al. 2010) identified seven specific radionuclides for analysis along with the need for gross alpha and gross beta radiological analyses. The analytes are {sup 241}Am, {sup 243}Am, {sup 244}Cm, {sup 60}Co, {sup 238}Pu, {sup 239}Pu, and {sup 233}U. The report also determined that air samples for particulates are the only sample matrix required for the monitoring program. These samples are collected on 47-mm glass-fiber filters.

  12. Behavior of actinides in the Integral Fast Reactor fuel cycle

    The Integral Fast Reactor (IFR) under development by Argonne National Laboratory uses metallic fuels instead of ceramics. This allows electrorefining of spent fuels and presents opportunities for recycling minor actinide elements. Four minor actinides (237Np, 240Pu, 241Am, and 243Am) determine the waste storage requirements of spent fuel from all types of fission reactors. These nuclides behave the same as uranium and other plutonium isotopes in electrorefining, so they can be recycled back to the reactor without elaborate chemical processing. An experiment has been designed to demonstrate the effectiveness of the high-energy neutron spectra of the IFR in consuming these four nuclides and plutonium. Eighteen sets of seven actinide and five light metal targets have been selected for ten day exposure in the Experimental Breeder Reactor-2 which serves as a prototype of the IFR. Post-irradiation analyses of the exposed targets by gamma, alpha, and mass spectroscopy are used to determine nuclear reaction-rates and neutron spectra. These experimental data increase the authors' confidence in their ability to predict reaction rates in candidate IFR designs using a variety of neutron transport and diffusion programs

  13. Analysis of high burnup spent nuclear fuel by ICP-MS

    Inductively coupled plasma mass spectrometry (ICP-MS) as the primary tool for determining concentrations of a suite of nuclides in samples excised from high-burnup spent nuclear fuel rods taken from light water nuclear reactors. The complete analysis included the determination of 95Mo, 99Tc, 101Ru, 103Rh, 109Ag, 137Cs, 143Nd, 145Nd, 148Nd, 147Sm, 149Sm, 150Sm, 151Sm, 152Sm, 151Eu, 153Eu, 155Eu, 155Gd, 237Np, 234U, 235U, 236U, 238U, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, 241Am, 242mAm, and 243Am. The isotopic composition of fissiogenic lanthanide elements was determined using high-performance liquid chromatography (HPLC) with ICP-MS detection. These analytical results allow the determination of fuel burn-up based on 148Nd, Pu, and U content, as well as provide input for storage and disposal criticality calculations. Results show that ICP-MS along with HPLC-ICP-MS are suitable of performing routine determinations of most of these nuclides, with an uncertainty of ±10% at the 95% confidence level. (author)

  14. Group neutron fission and radiative-capture cross-sections for transactinides

    A comparison is made between evaluations of radiative-capture and fission cross-sections for the isotopes 236U, 237Np, 238Pu, 241Am, 243Am, 242Cm and 244Cm, and group cross-sections for use in fast-reactor calculations are recommended. Group cross-sections obtained from the HEDL graphical data (evaluation for ENDF/B-V) are shown for 234U, 236Pu, 237Pu, 242Pu, 244Pu, sup(242m)Am, 241Cm, 243Cm and 248Cm. Group cross-sections for 32 isotopes from the ENDL-76 library files are also given. In choosing recommended cross-sections, account was taken of the extent of agreement with experimental data where these are available, the extent to which the cross-sections are documented and the extent to which they have been calculated from a theoretical model. The reliability of evaluations is discussed. An attempt is made to evaluate the error in single-group cross-sections averaged over a typical fast-reactor spectrum. Conclusions are drawn from a study of the literature on the current status of experimental and theoretical research on transactinide cross-sections, and from the spread of the different evaluation data. Finally, the situation with respect to the integral experiments which can be used for correcting transactinide cross-sections is discussed. (author)

  15. Radiation instrumentation: radiological chemistry

    Program efforts were concentrated in the following areas: development of low-level radiochemical laboratory techniques, in situ monitoring techniques, and activation analysis technology. Four different techniques were evaluated for borehole analysis of uranium and thorium ores. These involved the detection of fission product photons after 252Cf activation, the detection of low-energy gamma rays, the direct measurement of the 1001 keV photon from /sup 242m/Pa, a 238U daughter, and isotopic excitation x-ray fluorescence spectroscopy. X-ray fluorescence spectroscopy and detection of uranium daughter photons allowed 0.01% uranium to be detected. X-ray spectrometry of rare earth elements following activation analysis also allowed better elemental detection sensitivities to be obtained than did the detection of high-energy photons identified with a Ge(Li) detector in typical instrumental neutron activation analysis. An activation analysis facility is under development utilizing 252Cf in a 235U-fueled subcritical assembly. This assembly will be used to develop cyclic activation analysis techniques for some 65 elements in environmental matrices with sensitivities varying from parts per million to parts per billion. A study was initiated to identify instrumentation required for the measurement of transuranium elements associated with power reactor fuels. Transuranium isotopes, 237Pu, 238Pu, 239Pu, 241Am, 243Am, and 244Cm can be identified through low energy photons or x-rays emitted following alpha emission with planar intrinsic Ge detectors

  16. Maximization of burning and/or transmutation (B/T) capacity in coupled spectrum reactor (CSR) by fuel and core adjustment

    A conceptual design of burning and/or transmutation (B/T) reactor, based on a modified conventional 1150 MWe-PWR system, consisted of two core regions for thermal and fast neutrons, respectively, was proposed herein for the treatments of minor actinides (MA). In the outer region 237Np, 241Am, and 243Am burned by thermal neutrons, while in the inner region 244Cm was burned mainly by fast neutrons. The geometry of B/T fuel in the outer region was left the same with that of PWR, while in the inner region the B/T fuel was arranged in a tight-lattice geometry that allowed a higher fuel to coolant volume ratio. The maximization of B/T capacity in CSR were done by, first, increasing the radius of the inner region. Second, reducing the coolant to fuel volume ratio, and third, choosing a suitable B/T fuel type. The result of the calculations showed that the equilibrium of main isotopes in CSR can be achieved after about 5 recycle stages. This study also showed that the CSR can burn and transmute up to 808 kg of MA in a single reactor core effectively and safely. (author)

  17. Actinide behavior in the Integral Fast Reactor. Final project report

    The Integral Fast Reactor (IFR) under development by Argonne National Laboratory uses metallic fuels instead of ceramics. This allows electrorefining of spent fuels and presents opportunities for recycling minor actinide elements. Four minor actinides (237Np, 240Pu, 241Am, and 243Am) determine the waste storage requirements of spent fuel from all types of fission reactors. These nuclides behave the same as uranium and other plutonium isotopes in electrorefining, so they can be recycled back to the reactor without elaborate chemical processing. An experiment has been designed to demonstrate the effectiveness of the high-energy neutron spectra of the IFR in consuming these four nuclides and weapons grade plutonium. Eighteen sets of seven actinide and five light metal targets have been selected for seven day exposure in the Experimental Breeder Reactor-II which serves as a prototype of the IFR. Post-irradiation analyses of the exposed targets by gamma, alpha, and mass spectroscopy are used to determine nuclear reaction rates and neutron spectra. These experimental data increase the authors confidence in their ability to predict reaction rates in candidate IFR designs using a variety of neutron transport and diffusion programs

  18. Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE

    Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for 241Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for 243Am for neutron energies between 35 eV and 200 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on 242mAm will be presented, where the fission events were actively triggered during the experiments. In these experiments, the Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,γ) from (n,f) events. The first evidence of neutron capture on 242mAm in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

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

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

  20. Neutron capture and neutron-induced fission experiments on americium isotopes with DANCE

    Jandel, Marian [Los Alamos National Laboratory

    2008-01-01

    Neutron capture cross section data on Am isotopes were measured using the Detector for Advanced Neutron Capture Experiments (DANCE) at Los Alamos National Laboratory. The neutron capture cross section was determined for {sup 241}Am for neutron energies between thermal and 320 keV. Preliminary results were also obtained for {sup 243}Am for neutron energies between 35 eV and 200 keV. The results on concurrent neutron-induced fission and neutron-capture measurements on {sup 242m}Am will be presented, where the fission events were actively triggered during the experiments. In these experiments, the Parallel-Plate Avalanche Counter (PPAC) detector that surrounds the target located in the center of the DANCE array was used as a fission-tagging detector to separate (n,{gamma}) from (n,f) events. The first evidence of neutron capture on {sup 242m}Am in the resonance region in between 2 and 9 eV of the neutron energy was obtained.

  1. Measured solubilities and speciations of neptunium, plutonium, and americium in a typical groundwater (J-13) from the Yucca Mountain region

    Solubility and speciation data are important in understanding aqueous radionuclide transport through the geosphere. They define the source term for transport retardation processes such as sorption and colloid formation. Solubility and speciation data are useful in verifying the validity of geochemical codes that are part of predictive transport models. Results are presented from solubility and speciation experiments of 237NpO2+, 239Pu4+, 241Am3+/Nd3+, and 243Am3+ in J-13 groundwater (from the Yucca Mountain region, Nevada, which is being investigated as a potential high-level nuclear waste disposal site) at three different temperatures (25 degree, 60 degree, and 90 degree C) and pH values (5.9, 7.0, and 8.5). The solubility-controlling steady-state solids were identified and the speciation and/or oxidation states present in the supernatant solutions were determined. The neptunium solubility decreased with increasing temperature and pH. Plutonium concentrations decreased with increasing temperature and showed no trend with pH. The americium solutions showed no clear solubility trend with increasing temperature and increasing pH

  2. Evaluation of the contamination risk by {sup 241}AM from lightning rods disposed at uncontrolled garbage dump; Avaliacao da contaminacao provocada por para-raios radioativos de americio-241 descartados em lixoes

    Marumo, Julio Takehiro

    2006-07-01

    Radioactive lightning rods were manufactured in Brazil until 1989, when the licenses for using radioactive sources in these products were lifted by the national nuclear authority. Since then, radioactive devices have been replaced by Franklin type one and collected as radioactive waste. However, only 23 percent of the estimated total number of installed rods was delivered to Brazilian Nuclear Commission (Comissao Nacional de Energia Nuclear - CNEN). This situation is of concern as there is a possibility of the rods being discarded as domestic waste, considering that in Brazil, 63.6 percent of the municipal solid waste is disposed at uncontrolled garbage dump, according to Instituto Brasileiro de Geografia e Estatistica (IBGE) in 2000. In addition, americium, the most common employed radionuclide, is classified as a high toxicity element, when ingested or inhaled. In the present study, it was performed migration experiments of Am-241 by lysimeter system in order to evaluate the risk of contamination caused by radioactive lightning rods disposed as a common solid waste. Sources removed from lightning rods were placed inside lysimeters filled with organic waste, collected at the restaurant of Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN/SP, and the generated leachate was periodically analyzed to determine its characteristics such as pH, redox potential, solid content and concentration of the radioactive material. Microbial growth was also evaluated by counting the number of colony forming units. The equivalent dose to members of the public has been calculated considering the ingestion of drinking water, the most probable mode of exposure. The final result was about 145 times below the effective dose limit of 1 mSv.year-1 for members of the public, established by the International Commission on Radiological Protection (ICRP), demonstrating that the risk caused by lightning rods disposed at uncontrolled garbage dump is low. (author)

  3. 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

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

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

  5. CIEMAT results in IAEA proficiency tests in the context of emergency situations (210Po, 239,240Pu, 210Pb, gamma-emitters and 241Am) in environmental samples

    Three laboratories of CIEMAT with different: radiochemical procedures, detection capacity levels and counting equipment took part in the IAEA proficiency tests IAEA-CU-2007-09 and IAEA-CU-2007-04 (2007- 2008). This participation has allowed to compare and optimize some techniques in the case of emergency situations. The diverse methods used for the radionuclides determination, the capacity of each method for separating appropriately the radionuclides and their precision and trueness have been studied comparatively. The results of these exercises showed that the natural occurring radionuclides existing in the environmental samples are best isolated by time consuming analytical methods. Nevertheless, emergency methods require less manipulation, lower aliquot of sample and permit an acceptable detection limit for the radionuclides quantification. The selection of a radiochemical method for a specific purpose depends mainly on the sensibility required by the labs. The IAEA evaluation of the results as well as, our evaluation taking into account our capacities and objectives, are presented in this work. (author)

  6. Use of MCNP to compare the response of dose deposited in the TLD 100, TLD 600 and TLD 700 in radiation fields due to {sup 60}Co and {sup 241}AmBe source; Uso do MCNP para comparacao das respostas de dose depositada nos TLD 100, TLD 600 e TLD 700 em campos de irradiacao devido a fontes de {sup 60}Co e {sup 241}AmBe

    Cavalieri, Tassio A.; Castro, Vinicius A.; Siqueira, Paulo T.D., E-mail: tassio.cavalieri@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-08-15

    The successes of Boron Neutron Capture Therapy (BNCT) depend on the ability to deliver an adequate irradiation field to the target cells. Neutron beams used in BNCT are mostly driven from reactors and therefore, not only have a neutron energy range which far exceeds the thermal region but also do have a great gamma component. Beam characterization and dosimetry are consequently one of the essential procedures to be overcome to properly apply this technique. One of the methods currently used in mixed field (field containing both neutron and gamma) characterization, lies on the use of a pair of detectors with distinct responses to each beam component. But this technique needs to be better understood of how each thermoluminescent dosimeter (TLD) behaves in a mixed field or in a pure field. This work presents the results of a set of simulations performed in order to analyze the response of three ordinary types of TLDs - TLD 100, TLD 600 and TLD 700 - submitted to different irradiation fields from a Cobalt source and an Americium-Beryllium source inside a paraffin disk. And is also a possible method for performing the selection and calibration of theses TLDs. (author)

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

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

    2008-12-01

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

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

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

  9. RAPID DETERMINATION OF ACTINIDES IN URINE BY INDUCTIVELY-COUPLED PLASMA MASS SPECTROMETRY AND ALPHA SPECTROMETRY: A HYBRID APPROACH

    Maxwell, S.; Jones, V.

    2009-05-27

    A new rapid separation method that allows separation and preconcentration of actinides in urine samples was developed for the measurement of longer lived actinides by inductively coupled plasma mass spectrometry (ICP-MS) and short-lived actinides by alpha spectrometry; a hybrid approach. This method uses stacked extraction chromatography cartridges and vacuum box technology to facilitate rapid separations. Preconcentration, if required, is performed using a streamlined calcium phosphate precipitation. Similar technology has been applied to separate actinides prior to measurement by alpha spectrometry, but this new method has been developed with elution reagents now compatible with ICP-MS as well. Purified solutions are split between ICP-MS and alpha spectrometry so that long- and short-lived actinide isotopes can be measured successfully. The method allows for simultaneous extraction of 24 samples (including QC samples) in less than 3 h. Simultaneous sample preparation can offer significant time savings over sequential sample preparation. For example, sequential sample preparation of 24 samples taking just 15 min each requires 6 h to complete. The simplicity and speed of this new method makes it attractive for radiological emergency response. If preconcentration is applied, the method is applicable to larger sample aliquots for occupational exposures as well. The chemical recoveries are typically greater than 90%, in contrast to other reported methods using flow injection separation techniques for urine samples where plutonium yields were 70-80%. This method allows measurement of both long-lived and short-lived actinide isotopes. 239Pu, 242Pu, 237Np, 243Am, 234U, 235U and 238U were measured by ICP-MS, while 236Pu, 238Pu, 239Pu, 241Am, 243Am and 244Cm were measured by alpha spectrometry. The method can also be adapted so that the separation of uranium isotopes for assay is not required, if uranium assay by direct dilution of the urine sample is preferred instead

  10. Rapid analytical technique to identify alpha emitting isotopes in water, air-filters, urine, and solid matrices using a Frisch Grid detector.

    Scarpitta, Salvatore C; Miltenberger, Robert P; Gaschott, Robert; Carte, Nina

    2003-04-01

    A 5-inch-diameter Frisch Grid gas-proportional ionization chamber was utilized at Brookhaven National Laboratory (BNL) to rapidly characterize and quantify alpha-emitting actinides in unprocessed water, soil, air-filter, urine, and solid matrices. Instrument calibrations for the various matrices were performed by spiking representative samples with National Institute of Standards and Technology traceable isotopes of 230Th, 232U, 236Pu, and 243Am. Detection efficiencies were typically 15-20% for solid matrices (soil, concrete, filters, dry urine) and 45% for mass-less water samples. Instrument background over a 512-channel alpha-energy range of 3-8 MeV is very low at 0.01 cps. At optimum efficiency, minimum detectable levels of 0.56 mBq Kg(-1), 74 mBq L(-1) and 14.8 mBq filter(-1) were achievable for 40 x 10(-6) Kg soil, 1 x 10(-3) L tap water (or urine), and 4.5 cm diameter air-filter samples, respectively, each counted for 60 min. Data and spectra are presented showing the quality of results obtained using untreated samples obtained from the BNL Graphite Research Reactor Decommissioning Project. These samples contained Bq to MBq per gram amounts of (239,240)Pu, 241Am, and/or (234,235/238)U (as well as other beta/gamma emitters). Data and spectra are also presented for a very finely pulverized and homogeneous U.S. DOE/RESL soil reference standard (spiked with 239Pu, 241Am, and 233U) that was used to assess precision, accuracy, and reproducibility. Although this technique has its limitations, the advantages are (1) minimal sample preparation, (2) no separation chemistry required, (3) no chemical or hazardous waste generated, and (4) ability to immediately characterize and quantify alpha-emitting nuclides in most matrices. The benefits of this technique to the BNL/DOE Project Managers were rapid (1-2 d) turn-around times coupled with significant cost savings, as compared to commercial off-site analyses. PMID:12705448

  11. Transmutation of high level wastes in a fusion-driven transmuter (FDT)

    This study presents the transmutations of both the minor actinides (MAs: 237Np, 241Am, 243Am and 244Cm) and the long-lived fission products (LLFPs: 99Tc, 129I and 135Cs), discharged from high burn-up PWR-MOX spent fuel, in a fusion-driven transmuter (FDT) and the effects of the MA and LLFP volume fractions on their transmutations. The blanket configuration of the FDT is improved by analyzing various sample blanket design combinations with different radial thicknesses. Two different transmutation zones (TZMA and TZFP which contain the MA and LLFP nuclides, respectively) are located separately from each other. The volume fraction of the MA is raised from 10 to 20% stepped by 2%. The MAs are cladded with the graphite (10%) and cooled with the high-pressured helium gas for nuclear heat transfer. The volume fraction of helium is reduced from 80 to 70% depending on that of MA. Furthermore, the volume fraction of graphite is raised from 10 to 80% stepped by 5% to slow down the energy of neutrons entering into the TZFP while the volume fraction of LLFP is reduced from 80 to 10% depending on the graphite volume fraction. The calculations are performed for an operation period (OP) of up to 10 years by 75% plant factor (η) under a neutron wall load (P) of 5 MW/m2 to estimate neutronic parameters and transmutation characteristics per D-T fusion neutron. The transmutation rates of the LLFP nuclides increase linearly with the increase of volume fractions of the MA, and the 99Tc nuclide among them has the highest transmutation rate

  12. Determination of actinides by alpha spectrometric methods

    attributes of mass activities of radionuclides in oyster mushroom's sporocarps compared to their sub-base. We used two methods to separate the monitored radionuclides in a radiochemical analyse. The first of them was an extraction fluid - fluid with Aliquat-336 to separate Pu and TOPO to separate Am. The second method was a proceeding modified by us and utilizing principles of an extraction chromatography with TRU Resin and DGA Resin sorbents made by Eichrom Company. An effectivity and a suitability of both applied methods were monitored following the attributes of radiochemical extractions used in tracer's radionuclides 242Pu a 243Am in this particular type of environmental samples. The reliability of the modified methodology, in accordance to selected criteria for validation of analytical method, was proved by comparison of both above mentioned methods. material delivered from IAEA, which presented a soil sample with code identification Soil IAEA-375. The obtained values of mass activities of 239+240Pu, 239Pu and 241Am used in reference material, demonstrated a conformity with IAEA values, whereby we fulfilled one of the significant conditions of validate process. At the end of this thesis we applied the modified method of extraction chromatography with UTEVA Resin sorbent to define mass activities of uranium on soil and water samples where we monitored attributes of radiochemical extractions of 232U tracer's radionuclide as the criteria of utilizability. The reliability of our modified method was verified by participation in international interlaboratory comparative proficiency tests and our results were in accordance with results of the reference laboratory. It means also a fulfilment of notable standard of the validate process. The results of all realized experimentations of radionuclides separation whether by extraction fluid - fluid or by extraction chromatography were determined by alpha-spectrometric measurements. (author)

  13. Migration study of americium in porous medium

    Migration experiments of 241Am3+ had been performed by a column system, to investigate migration behavior of 241Am through a column packed porous sedimentary materials: a coastal sandy soil and a reddish soil. Most 241Am loaded into the column packed the reddish soil sorbed on the influent edge of the column. In the case of the sandy soil, however, considerable amount of 241Am was passed through the column. This shows that there is colloidal 241Am species which may move without effective interaction with the sandy soil. Such a migration behavior of colloidal 241Am in the sandy soil column could be evaluated by a sorption model based on filtration theory. Sorption mechanisms of 241Am on the sedimentary materials were examined by a chemical extraction method, for 241Am sorbed on the sandy soil and the reddish soil at any sections in the column. The 241Am sorbed on the reddish soil was mainly controlled by a reversible ion exchange reaction. On the other hand, the 241Am sorbed on the sandy soil ws controlled by irreversible reactions, such as the selective chemical sorptions onto Fe and Mn oxyhydroxide/oxide. The experimental results support that the migration of 241Am in the reddish soil layer can be estimated by using the Kd, whereas that in the sandy soil can not be explained by the Kd concept. (author)

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

    Waldo, R.W.

    1980-05-01

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

  15. Study of calculated and measured time dependent delayed neutron yields

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

  16. The absolute total delayed neutron yields, relative abundances and half-lives of delayed neutron groups in 6- and 8-group model format from neutron induced fission of 232Th, 233U, 236U, 239Pu, and 241Am in the energy range from 0.35 MeV (or threshold energy) to 5 MeV

    The latest evaluation of delayed neutron constants was made for main fuel nuclides (235U, 238U, 239Pu) within an working group under the auspices of the Nuclear Energy Agency’s (NEA) Working Party on International Evaluation Cooperation (WPEC), Subgroup 6 (SG6) in 1999 [1]. As a result of this work the total delayed yields for the above nuclides were essentially corrected as compared with Tuttle’s recommended data set [2]. For the total delayed yields from 238U correction is +5.6%, for thermal induced fission of 239Pu - +3.4% and for fast neutron induced fission of 239Pu - +3.2%. This is a direct indication that there is a need for a continuing effort on delayed neutron data improving. From now, this will be mainly directed at satisfying new requirements emerging from the current trends in reactor technology, such as: the use of high burn-up fuel, the burning of plutonium stocks, the general growing interest in fuel recycling strategies, and new concept of actinide burners

  17. Concentration and speciation of plutonium, americium, uranium, thorium, potassium and 137Cs in a venice canal sediment sample

    Testa, C.; Desideri, D.; Guerra, F.; Meli, M. A.; Roselli, C.; Degetto, S.

    1999-01-01

    A sequential extraction method consisting of six operationally-defined fractions has been developed for determining the geochemical partitioning of natural (U, Th, 40K) and antropogenic (Pu, Am, 137Cs) radionuclides in a 40-50 cm deep sediment sample collected in a Venice canal. Extraction chromatography with Microthene-TOPO (U, Th), Microthene-TNOA (Pu) and Microthene-HDEHP (Am) column was used for the chemical separation of a single radionuclide; the final recoveries were calculated by adding 236U, 229Th, 242Pu and 243Am as the yield tracers. After electrodeposition the alpha spectrometry was carried out. 137Cs and 40K were measured by gamma spectrometry. The total concentrations in the wet sample (Bq/kgd), obtained by a complete disgregation of the matrix by wet and dry treatment, were the following: 239+240Pu=1.03±0.07, 238Pu=0.022±0.005, 241Am=0.337±0.027, 137Cs=9.78±0.78, 238U=28.84±1.62, 232Th=21.42±1.93, 40K=376.05±12.78. The mean ratio 238Pu/239+240Pu (0.02) shows a contamination due essentially to fall-out and U and Th alpha spectra indicate the natural origin of two elements. The absence of 134Cs in the sample proves that at 40-50 cm depth the sediment was not affected by the Chernobyl fall-out. As far as the speciation is concerned the following fractions were considered: water soluble, carbonates, Fe-Mn oxides, organic matter, acid soluble, residue. Pu (˜67%) an Am (˜95%) were present principally in the carbonate fraction; U was more distributed and about 30% and 45% appeared in the carbonate fraction and in the residue respectively; the majority of Th was present in the residue (˜60%); 40K was totally present in the residue; finally 137Cs was found mostly in the acid soluble fraction (˜53%) and in the residue (˜47%). Some stable elements (Fe, Mn, Al, Ti, Ca, Pb, Ba) were also determined in the different fractions to get more information about the chemical association of the single radionuclides.

  18. ZZ SINEX, 100 Neutron-Group Neutron Reaction Cross-Section Library from ENDF/B by SUPERTOG for ANISN

    , Cl, K, Ca, V, Cr, 55-Mn, Fe, 59-Co, Ni, Cu, 63-Cu, 65-Cu, Nb, Mo, 107-Ag, 109-Ag, 135-Xe, 133-Cs, 149-Sm, 151-Eu, 153-Eu, Gd, 164-Dy, 175-Lu, 176-Lu, 181-Ta, 182-Ta, 182-W, 183-W, 184-W, 186-W, 185-Re, 187-Re, 197-Au, Pb, 232-Th, 233-Pa, 234-U, 235-U, 238-U, 238-Pu, 239-Pu, 240-Pu, 241-Pu, 242-Pu, 241-Am, 243-Am, and 244-Cm. 2 - Method of solution: DLC-24 was generated by SUPERTOG from nuclear data in either point-by-point or parametric representation as specified by ENDF/B. This data is averaged over each specified group width. For the top 99 groups, the explicit assumption was made that the flux (weighting function) has the shape of a fission spectrum jointed at 0.0674 MeV by a 1/E tail. When resonance data were available, resolved and unresolved resonance contributions were calculated, using the infinite dilution approximation. For the thermal group (group 100), values for all materials except hydrogen were taken from the Maxwellian average values derived from the ENDF/B data. The values for hydrogen are more consistent for hydrogen in water. It should be noted that these thermal group values are in some cases different from values used in the latest version of DLC-2

  19. ZZ DLC-2D/100G, 100 Neutron-Group Cross-Section Library by SUPERTOG Calculation for ANISN, DOT

    1 - Nature of physical problem solved: Format: ANISN, DOT or DTF-4; Number of groups: 100; Nuclides: H, D, He, He-3, Li-6, Li-7, Be-9, B-10, B-11, C-12, N-14, O-16, Na-23, Mg, Al-27, Si, Cl, K, Ca, V, Cr, Mn-55, Fe, Co-59, Ni, Cu, Cu-63, Cu-65, Nb, Mo, Ag-107, Xe-135, Cs-133, Sm-149, Eu-151, Eu-153, Gd, Dy-164, Lu-175, Lu-176, Ta-181, Ta-182, W-182, W-183, W-184, W-186, Re-185, Re-187, Au-197, Pb, Th-232, Pa-233, U-234, U-235, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-243, and Cm-244. Origin: The nuclides in DLC-2 are those which have been released as category I ENDF/B by the National Neutron Cross Section Center, Brookhaven National Laboratory. Weighting spectrum: The explicit assumption was made that the flux has the shape of a fission spectrum joined at 0.0674 MeV by a 1/E tail. Neutron transport calculations can be performed with DLC-2 data. Since the data are intended for use in multigroup discrete-ordinates or Monte Carlo transport codes which treat anisotropic scattering, possible cross section angular expansion is limited only by the options available in the particular code used. Specifically, the retrieval program manipulates DLC-2 such that it conforms to input requirements of the ANISN, DOT, or DTF-4 codes, or any computer code using data in the ANISN or DTF-4 format. The nuclides in DLC-2 are those which have been released as category I ENDF/B by the National Neutron Cross Section Center, Brookhaven National Laboratory. The library contains data for H, D, He, 3-He, 6-Li, 7-Li, 9-Be, 10-B, 11-B, 12-C, 14-N, 16-O, 23-Na, Mg, 27-Al, Si, Cl, K, Ca, V, Cr, 55-Mn, Fe, 59-Co, Ni, Cu, 63-Cu, 65-Cu, Nb, Mo, 107-Ag, 135-Xe, 133-Cs, 149-Sm, 151-Eu, 153-Eu, Gd, 164-Dy, 175-Lu, 176-Lu, 181-Ta, 182-Ta, 182-W, 183-W, 184-W, 186-W, 185-Re, 187-Re, 197-Au, Pb, 232-Th, 233-Pa, 234-U, 235-U, 238-U, 238-Pu, 239-Pu, 240-Pu, 241-Pu, 242-Pu, 241-Am, 243-Am, and 244-Cm. 2 - Method of solution: DLC-2 was generated by SUPERTOG from nuclear data in either point

  20. OREST, LWR Burnup Simulation Using Program HAMMER and ORIGEN

    printer-output. 3 - Restrictions on the complexity of the problem: NEA version is limited for 100 loops, 1000 burnup time-steps and 10 post-irradiation steps. GRS recommends the use of LWR fuels based on oxygen and on the main HAMMER isotopes 235-U, 236-U, 238-U, 237-Np, 238-Pu, 239-Pu, 240-Pu, 241-Pu, 242-Pu, 241-Am and 243-Am. Gadolinium entries should be handled with care if singular positions of Gd-rods in real assemblies are found. Other mixture entries at start of calculation should only be impurities. Cladding should be Zr, Al or stainless steel. Special options for handling other materials can be found in the user description. Activation of structure materials is not calculated. Strong heterogeneous assembly problems outside of the input data processor should be pre-calculated by using more-dimensional codes to achieve a neutron spectra equivalent HAMMER lattice (FEC-method). Coolant pressure, coolant temperatures and coolant steam contents are assumed to be constant during burnup. During each program loop neutron spectra and cross sections are assumed to be constant

  1. ZZ DLC-16 COBB, 123 Neutron-Group Cross-Section Library from ENDF/B for XSDRN Calculation

    1 - Nature of physical problem solved: Format: XSDRN; Number of groups: 123; Nuclides: H, D, He, Be-9, B-10, C-12, O-16, Na-23, Mg, Al-27, Ti, Cr, Mn-55, Fe, Ni, Cu, Cu-63, Cu-65, Nb-93, Mo, Xe-135, Sm-149, Eu-151, Eu-153, Gd, Dy-164, Lu-175, Lu-176, W-182, W-183, W-184, W-186, Re-185, Re-187, Au-197, U-233, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-243, and Cm-244. Origin: Mainly ENDF/B; Weighting spectrum: Fast cross sections → 1/E (14 MeV to .414 eV) Thermal cross sections → 1/E (1.86 eV to 0.125 eV) → Maxwell-Boltzmann (0.125 eV to 0.0047 eV). The library is intended to be a source of evaluated data for the cross section preparation code XSDRN. It supplements, rather than replaces, the existing XSDRN master library which is distributed with the code package. The library contains data for H, D, He, 9-Be, 10-B, 12-C, 16-O, 23-Na, Mg, 27-Al, Ti, Cr, 55-Mn, Fe, Ni, Cu, 63-Cu, 65-Cu, 93-Nb, Mo, 135-Xe, 149-Sm, 151-Eu, 153-Eu, Gd, 164-Dy, 175-Lu, 176-Lu, 182-W, 183-W, 184-W, 186-W, 185-Re, 187-Re, 197-Au, 233-U, 234-U, 235-U, 236-U, 238-U, 237-Np, 238-Pu, 239-Pu, 240-Pu, 241-Pu, 242-Pu, 241-Am, 243-Am, and 244-Cm. 2 - Method of solution: The library contains ENDF/B version 2 cross sections processed through several steps (primarily by SUPERTOG) into the standard XSDRN 123-group energy structure. These steps are - (a) process fast cross sections with SUPERTOG into standard GAM-2 energy structure (14 MeV to 0.414 eV), using a 1/E weighting function, and produce a GAM-2 tape. (This step was performed by R. Q. Wright, Math Div., ORNL). (b) Process thermal cross sections with SUPERTOG into standard 30-group THERMOS energy group structure (1.86 eV to 0.0047 eV), using a Maxwell-Boltzmann distribution with temperature 293 deg.K as a weighting function for E < 0.125 eV coupled to a 1/E weighting function for E from 0.125 eV to 1.86 eV. (c) Compute room temperature free-gas kernels, using THERMOS tape-making program, and

  2. 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

  3. 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

  4. Speciation of plutonium and americium in the soils affected by Kraton-3 accidental underground nuclear explosion in Yakutia (Russia)

    In calcareous soils from Yakutia only 0.1 % or less 239Pu and 241Am exist in water-soluble form, i.e., the mobility of these radionuclides is relatively low. In the top humus-containing layer (0-4 cm) 239Pu and 241Am are distributed uniformly between organic and inorganic soil components. In the bottom soil layer (20-30 cm) the radionuclides are present mainly in inorganic soil components. The estimation of the radionuclide mobility demonstrates that 241Am is potentially a more mobile element than 239Pu. In the considered calcareous soils collected from the top layer 239Pu and 241Am exist both in humic and fulvic acids (FA). 241Am is much stronger bound to the group of mobile FA than 239Pu. In the bottom soil layer 239Pu and 241Am have been found mainly in FA. (author)

  5. Recovery of Americium-241 from lightning rod by the method of chemical treatment

    About 95% of the lightning rods installed in the Peruvian territory have set in their structures, pose small amounts of radioactive sources such as Americium-241 (241Am), fewer and Radium 226 (226Ra) these are alpha emitters and have a half life of 432 years and 1600 years respectively. In this paper describes the recovery of radioactive sources of 241Am radioactive lightning rods using the conventional chemical treatment method using agents and acids to break down the slides. The 241Am recovered was as excitation source and alpha particle generator for analysing samples by X Ray Fluorescence, for fixing the stainless steel 241Am technique was used electrodeposition. (author)

  6. Speciation and bioavailability of Americium-241 in the fresh water environment

    Due to its anthropogenic origin, the transuranic americium 241 confronts physiologists with the intriguing question, which mechanisms are involved in the incorporation or elimination of such artificial elements in biological cycles. The investigations on the speciation and bioavailability of 241Am in the freshwater environment aim to establish a relation between the behavior of 241Am in freshwater ecosystems and its availability for biota. In the limnic environment, most often characterized by a high organic load and a low conductivity, the effect of complexation of 241Am with humic acids and competition with trivalent cations such as A1 and Fe, were proven to be significant on the speciation of 241Am. Based on the registration of the 241Am uptake by a large number of freshwater organisms, the crayfish Astacus leptodactylus Eschscholtz was chosen to study the whole-body uptake of 241Am, its corresponding organ distribution and its retention in the animal. The share of external fixation and ingestion in the global uptake, and the effect of speciation on it, were studied more carefully. Other aspects in this physiological part were: the kinetics of 241Am in the hemolymph and the hepatopancreas, and its subcellular distribution in the digestive gland. Finally, by comparing the physiology of 241Am with some other metals (240Pu, 64Cu, 198Au) with analogous or contradictional properties, we tried to find out whether the behavior of 241Am in organisms can be explained from its chemical characteristics

  7. Phytoremediation: role of terrestrial plants and aquatic macrophytes in the remediation of radionuclides and heavy metal contaminated soil and water.

    Sharma, Sunita; Singh, Bikram; Manchanda, V K

    2015-01-01

    Nuclear power reactors are operating in 31 countries around the world. Along with reactor operations, activities like mining, fuel fabrication, fuel reprocessing and military operations are the major contributors to the nuclear waste. The presence of a large number of fission products along with multiple oxidation state long-lived radionuclides such as neptunium ((237)Np), plutonium ((239)Pu), americium ((241/243)Am) and curium ((245)Cm) make the waste streams a potential radiological threat to the environment. Commonly high concentrations of cesium ((137)Cs) and strontium ((90)Sr) are found in a nuclear waste. These radionuclides are capable enough to produce potential health threat due to their long half-lives and effortless translocation into the human body. Besides the radionuclides, heavy metal contamination is also a serious issue. Heavy metals occur naturally in the earth crust and in low concentration, are also essential for the metabolism of living beings. Bioaccumulation of these heavy metals causes hazardous effects. These pollutants enter the human body directly via contaminated drinking water or through the food chain. This issue has drawn the attention of scientists throughout the world to device eco-friendly treatments to remediate the soil and water resources. Various physical and chemical treatments are being applied to clean the waste, but these techniques are quite expensive, complicated and comprise various side effects. One of the promising techniques, which has been pursued vigorously to overcome these demerits, is phytoremediation. The process is very effective, eco-friendly, easy and affordable. This technique utilizes the plants and its associated microbes to decontaminate the low and moderately contaminated sites efficiently. Many plant species are successfully used for remediation of contaminated soil and water systems. Remediation of these systems turns into a serious problem due to various anthropogenic activities that have

  8. Importance of neutron cross-sections for transmutation

    Accurate neutron cross-section data is fundamental to the reliable design of any transmutation device, and, in particular, of an accelerator-driven system (ADS). Calculations of the behaviour of the core depend strongly on the cross-section data: parameters such as the multiplication coefficient, power densities or reactivity may vary significantly depending on the nuclear-data (ND) library used. These potential discrepancies justify the need to improve the present data for several isotopes and reaction channels, for a wide range of neutron energies from thermal to high-energy. This paper follows on from work performed in the context of the nTOF-ND-ADS project of the EURATOM 5th framework program, where a preliminary analysis of the effects of different cross-section data was carried out using the Monte Carlo code package FLUKA-EAMC. That study was based on the Pb-Bi cooled 80 MWth energy-amplifier prototype, and included comparison of parameters such as source multiplication coefficient ksrc, neutron spectra, neutron balance and one-group cross-sections for different isotopes using different nuclear-data evaluations. The present work expands this analysis to other isotopes of interest such as 233U, 243Am, 244,245Cm and the long-lived fission fragments (LLFFs) 99Tc and 129I. A direct comparison of nuclear-data libraries to indicate the spread between values was performed. The paper also extends the sensitivity analysis of the parameters mentioned above to moderated systems, such as TRADE (triga accelerator-driven experiment): a 1 MW triga reactor coupled with a 110-140 MeV-2 mA proton cyclotron. Study of the discrepancies in the thermal and epithermal regions is essential for the design of systems for the transmutation of LLFF (transmutation by adiabatic resonance crossing, TARC) and also important for minor actinides (MAs) for which sub-threshold fission should not be neglected. These studies highlight the relative importance of different isotopes and assess the

  9. 1976 Hanford americium-exposure incident: accident description

    An accident is described, involving the explosion of an ion-exchange column containing about 100 g of 241Am. A chemical operator was injured in this accident, receiving acid burns and superficial cuts on the upper part of his body. From 1 to 5 curies of 241Am is estimated to have been deposited on the injured worker and on his clothing

  10. Inhaled americium dioxide

    This project includes experiments to determine the effects of Zn-DTPA therapy on the retention, translocation and biological effects of inhaled 241AmO2. Beagle dogs that received inhalation exposure to 241AmO2 developed leukopenia, clincial chemistry changes associated with hepatocellular damage, and were euthanized due to respiratory insufficiency caused by radiation pneumonitis 120 to 131 days after pulmonary deposition of 22 to 65 μCi 241Am. Another group of dogs that received inhalation exposure to 241AmO2 and were treated daily with Zn-DTPA had initial pulmonary deposition of 19 to 26 μCi 241Am. These dogs did not develop respiratory insufficiency, and hematologic and clinical chemistry changes were less severe than in the non-DTPA-treated dogs

  11. Investigation of the retention and distribution of americium-241 in the baboon and the enhanced removal of americium-241 from the body by diethylenetriaminepentaacetic acid (DTPA)

    Experiments were performed to study the metabolism and distribution of intravenously administered 241Am in the adult and juvenile baboon; in addition, decorporation therapy using Na3-CaDTPA was performed on selected baboons to assess the efficacy of this drug in removing systemic burdens of 241Am from this primate species. Determination of the kinetics of 241Am was accomplished principally by in vivo methodologies and by radiochemical analysis of 241Am activity of biological material. The use of Na3-CaDTPA as a therapeutic agent for the removal of 241Am from the body proved to be an effective form of treatment in the case of early administration. (U.S.)

  12. ZZ MCJEF22NEA.BOLIB, MCNP Cross Section Library Based on JEF-2.2

    1 - Description or function: Continuous energy cross-section data library for the Monte Carlo program MCNP based on the JEF-2.2 evaluated nuclear data library (ACE Format). Format: ACE Number of groups: Continuous energy Nuclides (107): H-1, H-2, He-4, Li-6, Li-7, Be-9, B-10, B-11, C-nat, N-14, N-15, O-16, O-17, F-19, Na-23, Mg-nat, Al-27, Si-nat, Cl-nat, Ti-nat, Cr-50, Cr-52, Cr-53, Cr-54, Mn-55, Fe-54, Fe-56, Fe-57, Fe-58, Co-59, Ni-58, Ni-60, Ni-61, Ni-62, Ni-64, Zr-90, Zr-91, Zr-92, Zr-94, Zr-96, Zr-nat, Nb-93, Mo-92, Mo-94, Mo-95, Mo-96, Mo-97, Mo-98, Mo-100, Mo-nat, Tc-99, Ru-101, Ru-102, Ru-104, Rh-103, Pd-105, Pd-107, Ag-109, I-129, Xe-131, Cs-133, Pr-141, Nd-143, Nd-145, Pm-147, Sm-147, Sm-149, Sm-150, Sm-151, Sm-152, Eu-153, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, Hf-174, Hf-176, Hf-177, Hf-178, Hf-179, Hf-180, Pb-nat, Bi-209, Th-232, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-239bis, Pu-240, Pu-241, Pu-242, Am-241, Am-242, Am-242m, Am-243, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246, Cm-247, Cm-248. Temperatures: 300 deg. K, 500 deg. K, 560 deg. K, 760 deg. K, 800 deg. K, 1000 deg. K, 1500 deg. K and 2200 deg. K. Thermal scattering (for diverse Temperatures); H in CH2 (polyethylene), H in H2O (light water), D in D2O (heavy water), C (graphite), Be (beryllium metal). Dosimetry cross-section: 16-S-32, 48-Cd-0, 79-Au-197; Origin: JEF-2.2, IRDF-90 V2. 2 - Methods: This library was generated with the NJOY-94.66 nuclear data processing system

  13. ZZ MCB63NEA.BOLIB, MCNP Cross Section Library Based on ENDF/B-VI Release 3

    1 - Description of program or function: Continuous energy cross-section data library for the Monte Carlo program MCNP based on the ENDF/B-VI Release 3 evaluated nuclear data library (ACE Format). Format: ACE; Number of groups: Continuous energy; Nuclides (107): H-1, H-2, He-4, Li-6, Li-7, Be-9, B-10, B-11, C-nat, N-14, N-15, O-16, O-17, Na-23, Mg-nat, Al-27, Si-nat, Cl-nat, Ti-nat, Cr-50, Cr-52, Cr-53, Cr-54, Mn-55, Fe-54, Fe-56, Fe-57, Fe-58, Co-59, Ni-58, Ni-60, Ni-61, Ni-62, Ni-64, Zr-90, Zr-91, Zr-92, Zr-94, Zr-96, Zr-nat, Nb-93, Mo-94, Mo-95, Mo-96, Mo-97, Mo-nat, Tc-99, Ru-101, Ru-102, Ru-104, Rh-103, Pd-105, Pd-107, Ag-109, I-129, Xe-131, Cs-133, Pr-141, Nd-143, Nd-145, Pm-147, Sm-147, Sm-149, Sm-150, Sm-151, Sm-152, Eu-153, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, Hf-174, Hf-176, Hf-177, Hf-178, Hf-179, Hf-180, Hf-nat, Pb-206, Pb-207, Pb-208, Bi-209, Th-232,U-233, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-242, Am-242m, Am-243, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246, Cm-247, Cm-248. Temperatures: 300 deg. K, 500 deg. K, 560 deg. K, 760 deg. K, 800 deg. K, 1000 deg. K, 1500 deg. K and 2200 deg. K. Thermal scattering (for diverse Temperatures): H in CH2 (polyethylene), H in H2O (light water), D in D2O (heavy water), C (graphite), Be (beryllium metal). Dosimetry cross-section: 16-S-32, 48-Cd-0, 79-Au-197. Origin: ENDF/B-VI Release 3, IRDF-90 Version 2. 2 - Methods: This library was generated with the NJOY-94.66 nuclear data processing system

  14. Method of preparation of tracer radionuclide 239Np using extraction chromatography

    This poster describes the preparation of tracers 239Np from 243Am. Used method involves stabilization of Np(IV) by ascorbic acid and ferric nitrate, separation of 239Np from 243Am using extraction chromatography and determination of activity of the solution obtained with 239Np using HPGe detector. In the experiment we used the commercially available sorbent TEVA Resin from the company Eichrom Technologies.

  15. Biosorption of radionuclide Americium-241 by A. niger spore and hyphae

    The biosorption of radionuclide 241Am from solution was studied by a. niger spore and hyphae, and the effects of the operational conditions on the treatment were investigated. The results showed the treatment by A. niger spore and hyphae were very efficient. An average of 96% of the total 241Am was removed from 241Am solutions of 5.6-111 MBq/L (C0), with adsorption capacities (W) of 7.2-142.4 MBq/g biomass, 5.2-106.5 MBq/g, respectively. The biosorption equilibrium was achieved within 1 h and the optimum pH value ranged 3-0.1 mol/L HNO3 and 3-2 for spore and hyphae of A. niger, respectively. No significant effects on 241Am biosorption were observed at 15 degree C-45 degree C, or challenged with containing Au3+ or Ag+, even 2000 times above 241Am amount. the index relationship between concentrations and adsorption capacities of 241Am indicated that the 241Am biosorption by A. niger spore and hyphae obey to Freundlich adsorption equation. The adsorption behavior of A. niger spore and hyphae were basically coincident

  16. In vitro studies of actinides and alveolar macrophages

    The toxicity of 239PuO2, 239Pu(NO3)4, and 241AmO2 to rabbit alveolar macrophages in culture was assessed. Comparison of toxicity of 239Pu(NO3)4 and 241AmO2 at the same radiation dose level indicates toxicity is due to radiation and not the chemical form of the actinide. Investigations were begun to determine the effect of serum macrophages and DTPA on 241AmO2 solubility

  17. Americium behaviour in plastic vessels

    Legarda, F.; Herranz, M. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R., E-mail: raquel.idoeta@ehu.e [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Abelairas, A. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2010-07-15

    The adsorption of {sup 241}Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of {sup 241}Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of {sup 241}Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  18. Estimation of americium in cemented waste block using gamma ray spectrometry

    A method was developed for the estimation of 241Am present in the cemented waste block which was cylindrical in shape. In such large sample, the attenuation of gamma rays increases with size of the sample and density of the material present. Attenuation correction was incorporated using linear attenuation coefficients of 59.54 keV gamma ray of 241Am. Also in such large samples, error due to the distribution of activity is more. Estimation of 241Am in the cemented sample was carried out by applying corrections for attenuation and for the sample geometry. (author)

  19. Contribution to the experimental study of transuranian element (Pu, Am, Cm) transfers between the various phases (particles, water, organisms) of the sedimentary system

    The methodology of this work is first given. Transfer kinetics of 237Pu, 241Am and 242Cm between seawater and macrofauna of loose substrates are studied. The effect of temperature and salinity over the transfers of 237Pu, 241Am and 242Cm between water and bivalve mollusk Tapes decussatus is then studied. This work deals also with transfer kinetics of these elements between carnivorous organisms of the loose substrates and their preys. A preliminary study of 241Am transfers between two phases, particles and interstitial water is finally presented: role of benthic burrowing organisms

  20. Americium behaviour in plastic vessels

    The adsorption of 241Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of 241Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of 241Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  1. Study of heavy elements at IMP

    The present status of heavy elements research at IMP (Institute of Modern Physics, Chinese Academy of Science, Lanzhou) is reviewed. Many efforts have been devoted into the stuclies of actinides and of transactinides. Some progresses have been made in synthesis and identification of new nuclides and studies of their exotic decay properties in these regions. The rapid chemical separation procedures have been widely applied when the half-lives of the expected nuclides are long enough. Three new neutron-rich isotopes of 237,238Th, 239Pa were produced by heavy-ion induced multinucleon transfer reaction and fast neutron-induced (n, 2p) reaction. A new neutron-deficient transuranium nuclide 235Am was also produced via proton-induced reaction and identified for the first time by using He-jet transportation, liquid-liquid extraction and x-γ coincidence measurements. The half-life of 235Am was determined to be 15±5 min. The β-delayed fission of 230Ac was observed for the first time and the BDF probability of 230Ac was determined to be (1.19±0.40)x10-8. Two new transactinide nuclides of 259Db and 265Bh were produced successfully via the reactions of 241Am(22Ne, 4n) 259Db and 243Am(26Mg, 4n) 265Bh, respectively at HIRFL (Heavy Ion Research Facility at Lanzhou). The high-radioactive americium targets with thickness of ∼1 mg/cm2 were prepared on 7μm aluminum or 15μm beryllium by molecular platting method at one single cycle. The reaction products were transported and collected using the helium-jet coupling with the rotating wheel apparatus. The identification of 259Db was based on the genetic relationship between the new activity and the known nuclide established by α-recoiled milking measurement. The half-life of 259Db were determined to be 0.5 s and the alpha energy was Ea = 9.47 MeV. Another new isotope 265Bh was identified based on observation of the α-α correlation between the 265Bh and its daughter 261Db and 257Lr nuclei using an improved rotating-wheel system

  2. Estimation of the solubility of radioactive aerosol particles in biological liquids

    Solubility of aerosol 'hot' particles sampled in 1987 in the town of Pripyat in the simulated lung fluid (SLF) (Gamble or Ringer solution) and in 0.1 M HCl was studied under static conditions. Leaching of radionuclides from the 'hot' particles in SFL decreases in the order 137Cs > 90Sr >> 239+240Pu > 241Am, and in 0.1 M HCl in the order 90Sr > 241Am >> 137Cs > 239+240Pu. The degree of passing into 0.1 M HCl solution for 90Sr and 241Am was estimated at 3.3-21 and 2.7-17%, respectively. Depending on the particle size, 0.06-2.2% of 241Am and 0.2-1.8% of 239+240Pu passes into SLF within 28 days

  3. The study of solubility Chernobyl 'hot' particles in simulated lung fluid

    The solubility of the aerosol 'hot' particles selected at Pripyat region in 1987 in simulated lung fluid (SLF - Gamble's or Pinger's solutions) and 0,1 M HCl was studied statistically. The result showed that leaching of the radionuclides in SLF decrease in line 137Cs > 90Sr >> 239+240Pu ≥ 241Am and in 0,1 M HCl 90Sr >241Am>> 137Cs ≥ 239+240Pu. In dissolution experiments with 0,1 M HCl estimated the soluble portion of the 90Sr and 241Am as 1,4 - 21,0 and 0,9 - 17,0 % correspondingly. In accordance with the size of the 'hot' particles 0,01 - 0,4 % 241Am and 0,02 - 0,3 % 239+240Pu were dissolve in the SLF during seven days

  4. Track segment studies with Chinese hamster cells

    Survival curves of near-diploid and near-tetraploid Chinese hamster cell cultures following irradiation by an 241Am α source indicate different growth rates for the two clones. Possible reasons for the difference are discussed

  5. Recovery of Americium-241 from lightning rod by the method of chemical treatment; Recuperacion del Americio-241 provenientes de los pararrayos por el metodo de tratamiento quimico

    Cruz, W.H., E-mail: wcruz@ipen.gob.pe [Instituto Peruano de Energia Nuclear (GRRA/IPEN), Lima (Peru). Division de Gestion de Residuos Radiactivos

    2013-07-01

    About 95% of the lightning rods installed in the Peruvian territory have set in their structures, pose small amounts of radioactive sources such as Americium-241 ({sup 241}Am), fewer and Radium 226 ({sup 226}Ra) these are alpha emitters and have a half life of 432 years and 1600 years respectively. In this paper describes the recovery of radioactive sources of {sup 241}Am radioactive lightning rods using the conventional chemical treatment method using agents and acids to break down the slides. The {sup 241}Am recovered was as excitation source and alpha particle generator for analysing samples by X Ray Fluorescence, for fixing the stainless steel {sup 241}Am technique was used electrodeposition. (author)

  6. 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

  7. Artificial radionuclides in the atmosphere over Lithuania

    Systematic observations of radionuclide composition and concentration in the atmosphere have been carried out at the Institute of Physics in Vilnius since 1963. An increase in activity concentration of radionuclides in the atmosphere was observed after nuclear weapon tests and the Chernobyl NPP accident. At present the radiation situation in Lithuania is determined by two main sources of radionuclides, forest fire and resuspension products transferred from highly polluted region of the Ukraine and Belarus. During forest fires the increase in activity concentration of 137Cs in the atmosphere was registered in many countries and in Lithuania as well. This work summarizes the experimental data on transport of cesium, plutonium, americium from the highly contaminated territories after the Chernobyl accident. The activity concentrations of 137Cs were measured in two - three days samples while plutonium and americium in monthly samples. In addition, the analyses of the events of the increase activity concentration, meteorological situation, speciation of radionuclides and mechanisms of formation and transformation of aerosol carriers of radionuclides are presented. Aerosols were sampled on perchlorvinyl filters and the large volume air samplers with a flow rate from 2400 m3/h to about 6000 m3/h were used. The radiochemical analyses of monthly samples of aerosol ashes (about 30 g) were performed. For separation of Pu isotopes the TOPO/cyclohexane extraction and radiochemical purification using UTEVA resin were performed, Am was separated after TOPO/cyclohexane extraction using TRU and TEVA resins (100-150 μm). 242Pu and 243Am were used as tracers in the separation procedure. The alpha spectrometry measurements of Pu and Am isotopes deposited on a stainless steel disc were carried out with the Alphaquattro (Silena) spectrometer. 137Cs was determined by gamma-ray spectrometry using the high purity HPGe detector (resolution - 1.9 keV/1.33 Mev, efficiency - 42%). Accuracy

  8. Biosorption of Americium-242 by saccharomyces cerevisiae: preliminary evaluation and mechanism

    As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high radiation toxicity and long half-life. In this experiment, the biosorption of 241Am from solution by a fungus, Saccharomyces cerevisiae (S. cerevisiae), and the effects of various experimental conditions on the biosorption and the mechanism were explored. The preliminary results showed that S. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total 241Am could be removed by S. cerevisiae of 2.1g/L (dry weight) from 241Am solutions of 2.22MBq/L -555 MBq/L (Co). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1-3. The culture times of more than 16 hours were suitable and the efficient adsorption of 241Am by the S. cerevisiae could be noted. The biosorption of 241Am by the decomposed cell wall, protoplasm or cell membrane of S. cerevisiae was same efficient as by the intact fungus, but the some components of S. cerevisiae, such as protein and acylation group had obvious effect on adsorption. When the concentrations of coexistent Eu3+, Nd3+ were 100 times more than that of 241Am, the adsorption rates would drop to 65%. However, most of the investigated acidic ions have no significant influence on the 241Am adsorption but minute change of pH value, while the saturated EDTA can strong inhibit the biosorption of 241Am.. (authors)

  9. Determination of mass attenuation coefficients of some boron ores at 59.54 keV by using scintillation detector

    The mass attenuation coefficients of the 59.54 keV radiation of 241Am point source in boron ores such as tincal, ulexite and colemanite were determined experimentally by a scintillation detector and theoretically. Since boron ores contain boron, hydrogen, and a lot of elements, they may be used as shielding against neutrons and gammas simultaneously, e.g. for shielding 241Am/Be neutron sources, as they emit both gammas and neutrons.

  10. Applying a low energy HPGe detector gamma ray spectrometric technique for the evaluation of Pu/Am ratio in biological samples

    The estimation of Pu/241Am ratio in the biological samples is an important input for the assessment of internal dose received by the workers. The radiochemical separation of Pu isotopes and 241Am in a sample followed by alpha spectrometry is a widely used technique for the determination of Pu/241Am ratio. However, this method is time consuming and many times quick estimation is required. In this work, Pu/241Am ratio in the biological sample was estimated with HPGe detector based measurements using gamma/X-rays emitted by these radionuclides. These results were compared with those obtained from alpha spectroscopy of sample after radiochemical analysis and found to be in good agreement. - Highlights: • High resolution gamma ray spectroscopy technique with low energy HPGe detector is used for the measurement of Pu isotopes and 241Am in biological samples. • Results obtained with gamma ray spectroscopy compared well with the results obtained from radiochemical analysis of sample followed by α-spectroscopy. • Results of this study will be useful for assessment and medical management of Pu/241Am embedded in tissue of workers

  11. Effect of americium-241 on luminous bacteria. Role of peroxides

    Alexandrova, M., E-mail: maka-alexandrova@rambler.r [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Rozhko, T. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Vydryakova, G. [Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation); Kudryasheva, N. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation)

    2011-04-15

    The effect of americium-241 ({sup 241}Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of {sup 241}Am in nutrient media (0.16-6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 {sup o}C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the {sup 241}Am is discussed. The effect of {sup 241}Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in {sup 241}Am solutions was demonstrated; and the similarity of {sup 241}Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions. - Highlights: {yields} Am-241 in water solutions (A = 0.16-6.7 kBq/L) suppresses bacterial growth.{yields} Am-241 (A = 0.16-6.7 kBq/L) stimulate bacterial luminescence. {yields} Peroxides, secondary radiolysis products, cause increase of bacterial luminescence.

  12. Modeling the effect of continuous infusion DTPA therapy on the retention and dosimetry of inhaled actinides

    A biokinetic model of the treatment of dogs that inhaled 241AmO2 aerosols with continuously infused DTPA has been adapted from a model previously published by Mewhinney and Griffith. This model simulated both the tissue retention and excretion of 241Am, and was used to estimate the cumulative radiation doses to tissues at risk from 241Am alpha radiation. The results showed that at 64 days after exposure, the liver dose of the DTPA-treated animals was 3% that of the corresponding controls, the skeletal dose was 2%, the kidney dose was 4%, and the lung dose was 67% of controls. This paper describes a biokinetic and dosimetric model that was adapted from a previously published model. It was developed to provide a means of estimating radiation doses for cases where continuously infused DTPA therapy is used to reduce radiation dose. The model was formulated for the case of 241Am02 inhalation, a physicochemical form of Am that is moderately soluble in vivo, and one to which people have been exposed. Because adequate human data, particularly tissue data, are not available from cases of accidental human exposure to 241Am, two published data sets from experiments in which Beagle dogs inhaled 241Am02 aerosols have been used to obtain parameter estimates for the model. The model simulations were then used to provide dose estimates with and without infused-DTPA therapy. (author)

  13. Effects of americium-241 and humic substances on Photobacterium phosphoreum: Bioluminescence and diffuse reflectance FTIR spectroscopic studies

    Kamnev, Alexander A.; Tugarova, Anna V.; Selivanova, Maria A.; Tarantilis, Petros A.; Polissiou, Moschos G.; Kudryasheva, Nadezhda S.

    The integral bioluminescence (BL) intensity of live Photobacterium phosphoreum cells (strain 1883 IBSO), sampled at the stationary growth stage (20 h), was monitored for further 300 h in the absence (control) and presence of 241Am (an α-emitting radionuclide of a high specific activity) in the growth medium. The activity concentration of 241Am was 2 kBq l-1; [241Am] = 6.5 × 10-11 M. Parallel experiments were also performed with water-soluble humic substances (HS, 2.5 mg l-1; containing over 70% potassium humate) added to the culture medium as a possible detoxifying agent. The BL spectra of all the bacterial samples were very similar (λmax = 481 ± 3 nm; FWHM = 83 ± 3 nm) showing that 241Am (also with HS) influenced the bacterial BL system at stages prior to the formation of electronically excited states. The HS added per se virtually did not influence the integral BL intensity. In the presence of 241Am, BL was initially activated but inhibited after 180 h, while the system 241Am + HS showed an effective activation of BL up to 300 h which slowly decreased with time. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, applied to dry cell biomass sampled at the stationary growth phase, was used to control possible metabolic responses of the bacteria to the α-radioactivity stress (observed earlier for other bacteria under other stresses). The DRIFT spectra were all very similar showing a low content of intracellular poly-3-hydroxybutyrate (at the level of a few percent of dry biomass) and no or negligible spectroscopic changes in the presence of 241Am and/or HS. This assumes the α-radioactivity effect to be transmitted by live cells mainly to the bacterial BL enzyme system, with negligible structural or compositional changes in cellular macrocomponents at the stationary growth phase.

  14. ZZ KAFAX-F31, 150 and 12 Groups Cross Section Library in MATXS Format based on JEFF-3.1 for Fast Reactors

    1 - Description: Format: MATXS, 142 nuclides processed with NJOY99.245. Number of groups: 150 neutron-, 12 photon-groups. 142 nuclides: H-1, H-2, He-3, He-4, Li-6, Li-7, Be-9, B-10, B-11, C-nat, N-14, N-15, O-16, F-19, Na-23, Mg-24, Mg-25, Mg-26, Al-27, Si-28, Si-29, Si-30, P-31, Cl-35, Cl-37, Ar-40, K-39, K-40, K-41, Ca-40, Ca-42, Ca-43, Ca-44, Ca-46, Ca-48, Ti-46, Ti-47, Ti-48, Ti-49, Ti-50, V-nat, Cr-50, Cr-52, Cr-53, Cr-54, Mn-55, Fe-54, Fe-56, Fe-57, Fe-58, Co-59, Ni-58, Ni-60, Ni-61, Ni-62, Ni-64, Cu-63, Cu-65, Ga-nat, Y-89, Zr-90, Zr-91, Zr-92, Zr-93, Zr-94, Zr-95, Zr-96, Nb-93, Mo-92, Mo-94, Mo-95, Mo-96, Mo-97, Mo-98, Mo-99, Mo-100, Ag-107, Ag-109, Cd-106, Cd-108, Cd-110, Cd-111, Cd-112, Cd-113, Cd-114, Cd-115m, Cd-116, Sn-112, Sn-114, Sn-115, Sn-116, Sn-117, Sn-118, Sn-119, Sn-120, Sn-122, Sn-123, Sn-124, Sn-125, Sn-126, Eu-151, Eu-153, Gd-152, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, W-182, W-183, W-184, W-186, Re-185, Re-187, Au-197, Pb-206, Pb-207, Pb-208, Bi-209, Th-232, Pa-233, U-233, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-242, Am-242m, Am-243, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246. Origin: JEFF-3.1. Weighting spectrum: 300, 600, 900, 1200 K. The KAFAX-F31 is a MATXS-format, 150-group neutron and 12-group photon cross section library for fast reactors based on JEFF-3.1. This library was originally generated for the KALIMER (Korea Advanced LIquid Metal Reactor) core analyses. It includes 142 nuclide data (Table 1) processed by the NJOY99.245 code patched with NEA020. The library can be utilized to generate the problem-dependent group constants for neutron and/or photon transport calculations through the DANTSYS, DOORS, or PARTISN code systems. 2 - Methods: The KAFAX-F31 was generated at 300, 600, 900, and 1200 K. It contains the self-shielded cross sections for 5 to 10 background cross sections depending on the nuclides. The neutron group structure consists of one-eighth lethargy widths in almost

  15. ZZ KAFAX-E70, 150 and 12 Groups Cross Section Library in MATXS Format based on ENDF/B-VII.0 for Fast Reactors

    1 - Description: Format: MATXS, 144 nuclides processed with NJOY99.245. Number of groups: 150 neutron-, 12 photon-groups. 144 nuclides: H-1, H-2, He-3, He-4, Li-6, Li-7, Be-9, B-10, B-11, C-nat, N-14, N-15, O-16, F-19, Na-23, Mg-24, Mg-25, Mg-26, Al-27, Si-28, Si-29, Si-30, P-31, Cl-35, Cl-37, Ar-40, K-39, K-40, K-41, Ca-40, Ca-42, Ca-43, Ca-44, Ca-46, Ca-48, Ti-46, Ti-47, Ti-48, Ti-49, Ti-50, V-nat, Cr-50, Cr-52, Cr-53, Cr-54, Mn-55, Fe-54, Fe-56, Fe-57, Fe-58, Co-59, Ni-58, Ni-60, Ni-61, Ni-62, Ni-64, Cu-63, Cu-65, Ga-69, Ga-71, Y-89, Zr-90, Zr-91, Zr-92, Zr-93, Zr-94, Zr-95, Zr-96, Nb-93, Mo-92, Mo-94, Mo-95, Mo-96, Mo-97, Mo-98, Mo-99, Mo-100, Ag-107, Ag-109, Cd-106, Cd-108, Cd-110, Cd-111, Cd-112, Cd-113, Cd-114, Cd-115m, Cd-116, Sn-112, Sn-113, Sn-114, Sn-115, Sn-116, Sn-117, Sn-118, Sn-119, Sn-120, Sn-122, Sn-123, Sn-124, Sn-125, Sn-126, Eu-151, Eu-153, Gd-152, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, W-182, W-183, W-184, W-186, Re-185, Re-187, Au-197, Pb-206, Pb-207, Pb-208, Bi-209, Th-232, Pa-233, U-233, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-242, Am-242m, Am-243, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246. Origin: ENDF/B-VII.0. Weighting spectrum: 300, 600, 900, 1200 k. The ZZ-KAFAX-E70 is a MATXS-format, 150-group neutron and 12-group photon cross section library for fast reactors based on ENDF/B-VII.0. This library was originally generated for the KALIMER (Korea Advanced Liquid Metal Reactor) core analyses. It includes 144 nuclide data processed with the NJOY99.245 code patched with NEA020. The library can be used to generate the problem-dependent group constants for neutron and/or photon transport calculations through the DANTSYS, DOORS, or PARTISN code systems. 2 - Methods: The KAFAX-E70 was generated at 300, 600, 900, and 1200 K. It contains the self-shielded cross sections for 5 to 10 background cross sections depending on the nuclides. The neutron group structure consists of one-eighth lethargy

  16. ZZ KAFAX-J33, 150 and 12 Groups Cross Section Library in MATXS Format based on JENDL-3.3 for Fast Reactors

    1 - Description: Format: MATXS, 136 nuclides processed with NJOY99.245. Number of groups: 150 neutron-, 12 photon-groups. 136 Nuclides: H-1, H-2, He-3, He-4, Li-6, Li-7, Be-9, B-10, B-11, C-nat, N-14, N-15, O-16, F-19, Na-23, Mg-24, Mg-25, Mg-26, Al-27, Si-28, Si-29, Si-30, P-31, Cl-35, Cl-37, Ar-40, K-39, K-40, K-41, Ca-40, Ca-42, Ca-43, Ca-44, Ca-46, Ca-48, Ti-46, Ti-47, Ti-48, Ti-49, Ti-50, V-nat, Cr-50, Cr-52, Cr-53, Cr-54, Mn-55, Fe-54, Fe-56, Fe-57, Fe-58, Co-59, Ni-58, Ni-60, Ni-61, Ni-62, Ni-64, Cu-63, Cu-65, Ga-69, Ga-71, Y-89, Zr-90, Zr-91, Zr-92, Zr-93, Zr-94, Zr-95, Zr-96, Mo-92, Mo-94, Mo-95, Mo-96, Mo-97, Mo-98, Mo-99, Mo-100, Ag-107, Ag-109, Cd-106, Cd-108, Cd-110, Cd-111, Cd-112, Cd-113, Cd-114, Cd-116, Sn-112, Sn-114, Sn-115, Sn-116, Sn-117, Sn-118, Sn-119, Sn-120, Sn-122, Sn-123, Sn-124, Sn-126, Eu-151, Eu-153, Gd-152, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, W-182, W-183, W-184, W-186, Pb-206, Pb-208, Bi-209, Th-232, Pa-233, U-233, U-234, U-235, U-236, U-238, Np-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-242, Am-242m, Am-243, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246. Origin: JENDL-3.3. Weighting spectrum: 300, 600, 900, 1200 K. The KAFAX-J33 is a MATXS-format, 150-group neutron and 12-group photon cross section library for fast reactors based on JENDL-3.3. This library was originally generated for the KALIMER (Korea Advanced LIquid Metal Reactor) core analyses. It includes 136 nuclide data processed by the NJOY99.245 code patched with NEA020. The library can be utilized to generate the problem-dependent group constants for neutron and/or photon transport calculations through the DANTSYS, DOORS, or PARTISN code systems. 2 - Methods: The KAFAX-J33 was generated at 300, 600, 900, and 1200 K. It contains the self-shielded cross sections for 5 to 10 background cross sections depending on the nuclides. The neutron group structure consists of one-eighth lethargy widths in almost all the energy ranges, except between 1 and 10 keV in

  17. Assay of TRU wastes containing (α,n) sources

    We have studied methods of determining alpha activity in transuranic waste from the gamma rays produced by the reactions (α,nγ), (α,pγ), and (α,α'γ) or produced directly by the alpha-emitting isotopes. Gamma-ray spectra were acquired for 20 drums of waste at the Stored Waste Examination Pilot Plant at Idaho National Engineering Laboratory with a high-purity germanium detector. To assist in the analysis, gamma-ray spectra were also acquired from the following standard neutron sources: 238Pu/Li, 241Am/Li, 241Am/Be, 241Am/B, 241Am/13C, 238PuO2, and 241AmF. Neutron measurements on the 20 drums were made in a combined passive and active neutron assay system for transuranic waste in Idaho. Representative gamma-ray spectra, line intensities, and calculated alpha activities for the drums are presented. In most matrix types, the alpha activity can be estimated from the neutron assay system results alone or from the reaction gamma-ray outputs. This work demonstrates a method of certifying the alpha activity, as well as the fissile content, of transuranic waste for the Waste Isolation Pilot Plant

  18. Proposals for setting possible limits on intake of transuranium radionuclides absorbed from the gastrointestinal tract

    The absorption of transuranium elements (238Pu, 241Am, 252Cf) from the gastrointestinal (GI) tract as influenced by physiological factors (e.g. age) and physical and chemical properties of compounds incorporated has been studied in 600 white mongrel rats. Average values of absorption have been determined for simple salts and a complex citrate. A number of factors increasing absorption have been found. Thus, originally bound compounds contained in the meat of animals incorporated with 238Pu and 241Am when alive, 241Am-containing potato juice and green oat stalks enhanced absorption by a factor of 5 to 30 as compared with an adequate control. Ethanol administered orally as a 20% solution increased the absorption of americium nitrate by 60% and that of citrate by 23%. Oral administratio of 241Am nitrate solution together with ferric chloride changes the metabolic kinetics of the nuclide completely. The total absorption of americium from DI tract is 7.1 times that of the control, but a considerable fraction absorbed into blood is excreted with urine (4.2% over 8 days). Among physiological factors age effects the absorption of transuranics from the GI tract to acertain degree. The absorption of 252Cf in 7 day-old young rats proves to be 8.1 times that of adults. Gestation brought about a 2.7 fold increase of 241Am absorption

  19. Radionuclide concentrations in bivalves collected along the coastal United States

    In 1990, the National Oceanic and Atmospheric Administration's National Status and Trends Program initiated a study of artificial radionuclides (241Am, 239+240Pu, 238Pu, 137Cs, 110Ag, 90Sr, 65Zn, 60Co, and 58Co) in oysters and mussels collected along the coastal US. The results of this study show that activation products 110Ag, 65Zn, 60Co and 58Co are sometimes present close to nuclear facilities. In addition, based on a nonparametric Kruskal-Wallis statistical test, it appears that 241Am and 137Cs concentrations as well as 241Am/239+240Pu and 137Cs/40K activity ratios are highest along the West Coast of the US. For 238Pu, 239+240Pu, and 90Sr activities and the other ratios, the differences observed in the distribution of the radionuclides between the various coasts are not statistically significant. There is also a statistical difference between the values of the 239+240Pu/90Sr ratio in oysters vs mussels collected along the East Coast and of the 241Am/239+240Pu ratio between two species of mussels collected along the West Coast. Finally, when the NOAA results for 241Am, 239+240Pu, and 137Cs are compared with those of an earlier (1976-1978) Mussel Watch Program sponsored by the Environmental Protection Agency, the statistical Sign Test generally shows a significant decrease in the concentrations between the mid-1970s and the early 1990s. (author)

  20. Study for correction of neutron scattering in the calibration of the albedo individual monitor from the Neutron Laboratory (LN), IRD/CNEN-RJ, Brazil; Estudo da correcao do espalhamento de neutrons na calibracao do monitor individual de albedo no LN

    Freitas, B.M.; Silva, A.X. da, E-mail: bfreitas@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Mauricio, C.L.P.; Martins, M.M. [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    The Instituto de Radioprotecao e Dosimetria (IRD) runs a neutron individual monitoring service with albedo type monitor and thermoluminescent detectors (TLD). Moreover the largest number of workers exposed to neutrons in Brazil is exposed to {sup 241}Am-Be fields. Therefore a study of the response of albedo dosemeter due to neutron scattering from {sup 241}Am-Be source is important for a proper calibration. In this work, it has been evaluated the influence of the scattering correction in two distances at the Low Scattering Laboratory of the Neutron Laboratory of the Brazilian National Laboratory (Lab. Nacional de Metrologia Brasileira de Radiacoes Ionizantes) in the calibration of that albedo dosemeter for a {sup 241}Am-Be source. (author)

  1. Comparative study of plutonium and americium bioaccumulation from two marine sediments contaminated in the natural environment

    Plutonium and americium sediment-animal transfer was studied under controlled laboratory conditions by exposure of the benthic polychaete Nereis diversicolor (O. F. Mueller) to marine sediments contaminated by a nuclear bomb accident (near Thule, Greenland) and nuclear weapons testing (Enewetak Atoll). In both sediment regimes, the bioavailability of plutonium and 241Am was low, with specific activity in the tissues 241Am occurred and 241Am uptake from the Thule sediment was enhanced compared to that from lagoon sediments of Enewetak Atoll. Autoradiography studies indicated the presence of hot particles of plutonium in the sediments. The results highlight the importance of purging animals of their gut contents in order to obtain accurate estimates of transuranic transfer from ingested sediments into tissue. It is further suggested that enhanced transuranic uptake by some benthic species could arise from ingestion of highly activity particles and organic-rich detritus present in the sediments. (author)

  2. Transuranium element transport in agricultural systems (soil to food chain transfer of nuclear fuel cycle radionuclides). Annual progress report

    Progress is reported on the following research projects: preparation of bibliography covering literature on plant uptake of transuranium elements; development of techniques for growth of agricultural crops in large containers that simulate field conditions; equipment for counting of alpha-emitting transuranium elements; studies on variability in concentration ratio of 241Am under different environmental conditions; alpha radiation burn in bush beans exposed to 241Am in solution; constancy of concentration ratio as a measure of plant uptake of 241Am; growth of radishes in soil with and without DTPA, and radish peel as source of radionuclides; effects of varying levels of DTPA in loam soil on concentration ratio values; and a plant species (Atriplex hymenelytra--desert holly) with high C.R. values and search for other plants with high C.R. values

  3. Standard practice for The separation of americium from plutonium by ion exchange

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This practice describes the use of an ion exchange technique to separate plutonium from solutions containing low concentrations of americium prior to measurement of the 241Am by gamma counting. 1.2 This practice covers the removal of plutonium, but not all the other radioactive isotopes that may interfere in the determination of 241Am. 1.3 This practice can be used when 241Am is to be determined in samples in which the plutonium is in the form of metal, oxide, or other solid provided that the solid is appropriately sampled and dissolved (See Test Methods C758, C759, and C1168). 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  4. Transportability Class of Americium in K Basin Sludge under Ambient and Hydrothermal Processing Conditions

    Delegard, Calvin H.; Schmitt, Bruce E.; Schmidt, Andrew J.

    2006-08-01

    This report establishes the technical bases for using a ''slow uptake'' instead of a ''moderate uptake'' transportability class for americium-241 (241Am) for the K Basin Sludge Treatment Project (STP) dose consequence analysis. Slow uptake classes are used for most uranium and plutonium oxides. A moderate uptake class has been used in prior STP analyses for 241Am based on the properties of separated 241Am and its associated oxide. However, when 241Am exists as an ingrown progeny (and as a small mass fraction) within plutonium mixtures, it is appropriate to assign transportability factors of the predominant plutonium mixtures (typically slow) to the Am241. It is argued that the transportability factor for 241Am in sludge likewise should be slow because it exists as a small mass fraction as the ingrown progeny within the uranium oxide in sludge. In this report, the transportability class assignment for 241Am is underpinned with radiochemical characterization data on K Basin sludge and with studies conducted with other irradiated fuel exposed to elevated temperatures and conditions similar to the STP. Key findings and conclusions from evaluation of the characterization data and published literature are summarized here. Plutonium and 241Am make up very small fractions of the uranium within the K Basin sludge matrix. Plutonium is present at about 1 atom per 500 atoms of uranium and 241Am at about 1 atom per 19000 of uranium. Plutonium and americium are found to remain with uranium in the solid phase in all of the {approx}60 samples taken and analyzed from various sources of K Basin sludge. The uranium-specific concentrations of plutonium and americium also remain approximately constant over a uranium concentration range (in the dry sludge solids) from 0.2 to 94 wt%, a factor of {approx}460. This invariability demonstrates that 241Am does not partition from the uranium or plutonium fraction for any characterized sludge matrix. Most

  5. Synthesis and Physicochemical Characterization of a Diethyl Ester Prodrug of DTPA and Its Investigation as an Oral Decorporation Agent in Rats.

    Huckle, James E; Sadgrove, Matthew P; Leed, Marina G D; Yang, Yu-Tsai; Mumper, Russell J; Semelka, Richard C; Jay, Michael

    2016-07-01

    The increasing threats of nuclear terrorism have made the development of medical countermeasures a priority for international security. Injectable formulations of diethylenetriaminepentaacetic acid (DTPA) have been approved by the FDA; however, an oral formulation is more amenable in a mass casualty situation. Here, the diethyl ester of DTPA, named C2E2, is investigated for potential as an oral treatment for internal radionuclide contamination. C2E2 was synthesized and characterized using NMR, MS, and elemental analysis. The physiochemical properties of solubility, lipophilicity, and stability were investigated in order to predict its oral bioavailability. Finally, an animal efficacy study was conducted in Sprague Dawley rats pre-contaminated by intramuscular injection with (241)Am(NO3)3 to establish effectiveness of the therapy via the oral route. Synthesis of C2E2 yielded a crystalline powder with high solubility and improved lipophilicity over DTPA. The ester was stable in both simulated gastric and intestinal fluids over the anticipated time course of absorption. Capsules containing C2E2 were demonstrated to be stable for 12 months under accelerated stability conditions. After a single dose, C2E2 enhanced the elimination of (241)Am in a dose-dependent manner. Significant improvement was seen in both total (241)Am decorporation and reduction of (241)Am liver and skeletal burden. C2E2 was concluded to be effective when orally administered to (241)Am-contaminated rats. It may therefore have potential for medical countermeasure in treating humans contaminated with (241)Am or other transuranic elements. An oral capsule or powder for reconstitution may be suitable formulations for future development based on the physiochemical properties and anticipated dose required for efficacy. PMID:27106838

  6. Comparative studies on transuranium nuclide biokinetics in sediment-dwelling invertebrates

    Sediment-dwelling molluscs (bivalve and gastropod), echinoderms (ophiuroid and holothurian) and annelids (polychaete) were analyzed for accumulation tissue distribution and loss of 237Pu, 241Am and 242Cm. After a 3-week exposure to a given radionuclide organisms were transferred to clean sea water for the depuration phase. Some individuals were dissected following both the uptake and loss period. Concentration factors varied widely (1-103), strongly dependent on species and radionuclide. All species tested took up more 241Am than 237Pu with the exception of the brittle star Ophiura texturata which showed a preference for 237Pu over 241Am by a factor of 5. The highest uptake of 241Am was noted in the polychaete Hermione hystrix which reached concentration factors of 103 and showed no indication of approaching steady state after 20 days. The detritivorous gastropod Aporrhais pespelicani attained somewhat higher 241Am concentration factors (550) than did the suspension-feeding clam (330). The lowest 241Am concentration factors were found in the brittle star (60) and the sea cucumber Stichopus regalis (20). Transuranics accumulated in polyaetes > molluscs > echinoderms, with ophiuroids reaching higher levels than holothurians, most of the radionuclides (80-90%) associating with shell or body wall. Particularly high concentration factors (103-104) were noted in chitinous setae of the polychaete and digestive tissues and gonads of the ophiuroid. Tranfer probably takes place via the coelomic fluid. Tbsub(1/2) ranged from 2-13 months, a function of species rather than the transuranic element. Benthic species of the sediment-water interface can readily accumulate transuranic elements retaining them for relatively long periods of time

  7. Prediction of in vivo background in phoswich lung count spectra

    Phoswich scintillation counters are used to detect actinides deposited in the lungs. The resulting spectra, however, contain Compton background from the decay of 40K, which occurs naturally in the striated muscle tissue of the body. To determine the counts due to actinides in a lung count spectrum, the counts due to 40K scatter must first be subtracted out. The 40K background in the phoswich NaI(Tl) spectrum was predicted from an energy region of interest called the monitor region, which is above the 238Pu region and the 241Am region, where photopeaks from 238Pu and 241Am region, where photopeaks from 238Pu and 241Am occur. Empirical models were developed to predict the backgrounds in the 238Pu and 241Am regions by testing multiple linear and nonlinear regression models. The initial multiple regression models contain a monitor region variable as well as the variables gender, (weight/height)α, and interaction terms. Data were collected from 64 male and 63 female subjects with no internal exposure. For the 238Pu region, the only significant predictor was found to be the monitor region. For the 241Am region, the monitor region was found to have the greatest effect on prediction, while gender was significantly only when weight/height was included in a model. Gender-specific models were thus developed. The empirical models for the 241Am region that contain weight/height were shown to have the best coefficients of determination (R2) and the lowest mean squares for error (MSE)

  8. An in situ survey of Clean Slate 1, 2, and 3, Tonopah Test Range, Central Nevada. Date of survey: September--November 1993

    A ground-based in situ radiological survey was conducted downwind of the Clean Slate 1, 2, and 3 nuclear safety test sites at the Tonopah Test Range in central Nevada from September through November 1993. The purpose of the study was to corroborate the americium-241 (241Am) soil concentrations that were derived from the aerial radiological survey of the Clean Slate areas, which was conducted from August through October 1993. The presence of 241Am was detected at 140 of the 190 locations, with unrecoverable or lost data accounting for fifteen (15) of the sampling points. Good agreement was obtained between the aerial and in situ results

  9. In vivo measurements of exposed individuals

    This section describes several studies of exposed individuals and the actual in vivo measurements made at this laboratory during the past three years. In all cases, the nuclides being measured are bone seekers and were measured with NaI(Tl)-CsI(Tl) detectors above the thorax or surrounding the head. The studies include the measurement of occupational contamination for 241Am, metabolic studies of 241Am in a child and his father, estimation of employee exposures to compounds of depleted uranium, measurements of residents of the Marshall Islands and measurement of occupational contamination for lead (Pb-210)

  10. Soluble and particle-associated fallout radionuclides in Mediterranean water and sediments

    From measurements in Mediterranean seawater and sediments, fallout 137Cs, 90Sr, and 239240Pu behaved mostly as soluble nuclides tracing Mediterranean water movement, whereas 55Fe and 241Am behaved more as particle-associated nuclides and were relatively rapidly removed to the sediments. Patterns of nuclide distribution within sediments showed depths of penetration in the order 55Fe > (239240Pu, 137Cs) > 241Am and were thought to result from biological mixing on nuclides whose arrival rates varied in the same order

  11. Radiometric dating of the United Kingdom SWAP sites

    Measurements of 210Pb by direct gamma assay have been used to date sediment cores from Surface Water Acidification Project (SWAP) study sites in the U.K. The results were checked against additional dating evidence from the artificial fallout isotopes 137Cs and 241Am. At one of the sites, Devoke Water in Cumbria, the 137Cs and 241Am data were crucial in identifying a recent sediment hiatus. At sites with recently afforested catchments the sediment record indicated substantial increases in accumulation rates. (author)

  12. Preparation of americium source for smoke detector

    This report describes the method developed for the preparation of 241Am source for smoke detector. Americium was electrodeposited from iso-propyl alcohol medium on silver backing. Thin layer of gold (few hundred micro gram thick) was plated on the americium source to make it safe for handling. The thickness of plated gold was such that the alpha radiations from the 241Am source could escape out of the gold layer and cause ionisation in the surrounding air. The performance of the prepared sources were checked in a smoke detector and was found to be satisfactory and comparable to the imported sources. (author). 1 refs., 2 figs., 1 tab

  13. Experimental optimization of a landmine detection facility using PGNAA method

    The optimum moderator geometry increases the performance of prompt gamma neutron activation analysis (PGNAA) method considerably. In this work an 241Am-Be source was used in the moderator geometry for detecting buried landmines by PGNAA method. Experiments were done to find the best moderator geometry for the moderated 241Am-Be source, by replacing the mine with a neutron detector and counting the thermal neutron flux. The flux of thermal neutrons at the place of mine was used as a determining factor to introduce the best moderator geometry. (authors)

  14. Experimental optimization of a landmine detection facility using PGNAA method

    Hashem MIRI-HAKIMABAD; Hamed PANJEH; Alireza VEJDANI-NOGHREIYAN

    2008-01-01

    The optimum moderator geometry increases the performance of prompt gamma neutron activation analysis (PGNAA) method considerably. In this work an 241Am-Be source was used in the moderator geometry for detecting buried landmines by PGNAA method. Experiments were done to find the best moderator geometry for the moderated 241 Am-Be source, by replacing the mine with a neutron detector and counting the thermal neutron flux. The flux of thermal neutrons at the place of mine was used as a determining factor to introduce the best moderator geometry.

  15. High resolution alpha spectroscopy with low cost photodiodes

    Energy resolution for α-spectra comparable to that from good quality surface barrier detectors has been obtained with inexpensive commercial silicon photodiodes. Using a low noise charge-sensitive preamplifier, an alpha energy resolution of less than 15 keV (fwhm) was achieved for 5.486 MeV α-particles from 241Am; this performance enables fine structure peaks to be clearly observed for 239Pu, 241Am, and 244Cm in a mixed α-source. The energy response was found to be highly linear and stable over long periods of operation. Results for other radiations are also briefly described. (orig.)

  16. An in situ survey of Clean Slate 1, 2, and 3, Tonopah Test Range, Central Nevada. Date of survey: September--November 1993

    NONE

    1995-08-01

    A ground-based in situ radiological survey was conducted downwind of the Clean Slate 1, 2, and 3 nuclear safety test sites at the Tonopah Test Range in central Nevada from September through November 1993. The purpose of the study was to corroborate the americium-241 ({sup 241}Am) soil concentrations that were derived from the aerial radiological survey of the Clean Slate areas, which was conducted from August through October 1993. The presence of {sup 241}Am was detected at 140 of the 190 locations, with unrecoverable or lost data accounting for fifteen (15) of the sampling points. Good agreement was obtained between the aerial and in situ results.

  17. Development of a dielectric microcalorimeter by using 0.99SrTiO3-0.01SrTa2O6 materials

    A microcalorimeter chip was fabricated by using 0.99SrTiO3-0.01SrTa2O6 dielectric material. After cooling down below 100mK, the dielectric microcalorimeter was irradiated by α particles emitted from an 241Am source. The operating temperature of the dielectric microcalorimeter was maintained by operating a liquid helium-free compact dilution refrigerator. The dielectric microcalorimeter was irradiated by 5.5MeVα particles emitted from an 241Am source at the temperature of 100mK. By applying the bias voltage, detection signal pulses were observed at the output of a charge-sensitive preamplifier

  18. Analysis of a liquid sample residue using in situ alpha spectrometry

    Three in situ alpha spectrometry methods were demonstrated to rapidly detect alpha-particle emitting radionuclides from a liquid sample. The liquid containing natU and 241Am was evaporated under an infrared lamp and the residue was analyzed in a vacuum and at ambient air pressure. The residue was too thick to determine activities of individual nuclides, but their identification and activity ratio calculations were possible. U and 241Am behaved differently during the liquid dry off, which led to alpha peaks of different shape. This finding should be taken into account for preparing future spectrum unfolding programs. (author)

  19. Modifying radionuclide effects

    This project involves a study of the relationship of physiological and environmental factors to the metabolism and effects of radionuclides. We have studied placental transfer and suckling as pathways of americium entry into the newborn or juvenile rat. Rats were injected intravenously with 5 μCi of 241Am while nulliparous (30 days prior to mating), pregnant (day 19 of gestation), or lactating (1 day after parturition), and subsequent litters were killed to determine 241Am retention. A deficit in reproductive performance was observed in the group injected before mating, as evidenced by reduced number and weight of offspring

  20. Above-threshold structure in {sup 244}Cm neutron-induced fission cross section

    Maslov, V.M. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    The quasi-resonance structure appearing above the fission threshold in neutron-induced fission cross section of {sup 244}Cm(n,f) is interpreted. It is shown to be due to excitation of few-quasiparticle states in fissioning {sup 245}Cm and residual {sup 244}Cm nuclides. The estimate of quasiparticle excitation thresholds in fissioning nuclide {sup 245}Cm is consistent with pairing gap and fission barrier parameters. (author)

  1. Determination of mass attenuation coefficient in wood and leaves of typical trees by gamma-ray attenuation technique

    Using an 241 Am source the mass attenuation coefficient of different woods and leaves of typical species of the Atlantic Forest were measured. The results for natural wood, dry wood and dry leaves indicate that the variation is very small among different species. However, woods present a higher attenuation than leaves, both depending on their water content. (author). 10 refs., 3 figs., 1 tab

  2. Equilibrium constant for aqueous mono fluoro complex of Am(III) by solvent extraction and ion exchange

    Stability constant of Am(III)-F has been measured by distribution method using two extractants and two cation exchangers. Distribution ratios were measured by counting γ activity from 241Am and the equilibrium free fluoride by ion selective potentiometry. The value of log β1 is 2.48 ± 0.02. (author). 5 refs., 1 tab

  3. MEASUREMENT OF WHEAT DENSITY

    冯跟胜; 党金春; 等

    1995-01-01

    A method used for on line determining the change of wheat density with a automatic watering machine in a lqarge flour mill has been studied.The results show that the higher distinguishing ability is obtained when using 241Am as a γ-ray source for measuring the wheat density than using 137Cs.

  4. New experimental set-ups for investigating properties of the spontaneously fissionable 242Am isomer in the IBR-30 and IBR-2 pulsed reactors

    The mean neutron number per isomeric fission event of 242Am is measured. Correlations between the isomeric fission probabilities and the fission widths of neutron resonance of 241Am are investigated. For these experiments neutron time-of-flight spectrometers based on pulsed reactors IBR-30 and IBR-2 at the JINR Dubna are used

  5. Calibration of whole-body counters for transuranic radionuclides by using total-body donations to the United States Transuranium Registry

    One of the many benefits of the whole-body donation programme of the United States Transuranium Registry is the calibration of whole-body counters by measuring a donated body containing radioactivity before radiochemical analysis of the body occurs. These measurements have provided the best existing calibration factors for measuring 241Am and 239Pu in the skeleton of living people. In one case where the body contained an easily measurable quantity of 241Am, the 241Am content was found to be the same for identical bones on the right and left sides of the body. The bones from the right side of the body and every other vertebrae were radiochemically analysed and the bones from the left side were reserved. These latter have a known quantity of naturally distributed 241Am based on the analysis of bones from the right side. These reserved bones are being incorporated into tissue equivalent body parts for future calibrations and interlaboratory comparisons. The measurements on the total body and the reserved bones have already been very useful in determining the contribution of skeletal activity to that of lung measurements and determining a calibration factor for measuring 239Pu deposited in the skeleton. In the future it is planned to periodically make in vivo measurements on those people participating in the total-body donation programme so that calibration factors can be obtained for lung and liver content after subsequent analysis of these tissues. (author)

  6. Neutron spectra and dosimetric features of isotopic neutron sources: a review

    A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of 24NaBe, 24NaD2O, 116InBe, 140LaBe, 238PuLi, 239PuBe, 241AmB, 241AmBe, 241AmF, 241AmLi, 242CmBe, 210PoBe, 226RaBe, 252Cf and 252Cf/D2O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

  7. Preface to the injection tables

    Twelve groups of dogs received intravenous injections of various doses of 226Ra, 239Pu, 228Ra, 228Th, 90Sr, 241Am, 249Cf, or 252Cf at approximately 17 months of age. The animals were euthanized when death appeared imminent. Data are presented on the calculated radiation dose to the skeleton and pathological changes observed at autopsy

  8. Options for clean-up of the Maralinga test site

    This report examines the limit of contamination of the soil and ground cover by 239Pu, 235U and 241Am which may be considered as permitting the unrestricted land use of the former nuclear weapon test sites at Emu and Maralinga by Aboriginal groups. It reports on the options available to achieve this objective and their cost

  9. Hanford intercontractor support

    Distribution coefficients (Kd values) were determined on subsoils from Washington and South Carolina for 241Am, 237Np, and 99Tc as a function of equilibrium solution concentration of calcium (Ca2+) and of sodium (Na+). Kd values decreased in all cases with increasing solution concentrations of Ca2+ and Na+. For the South Carolina subsoil Kd values ranged from 1.0 to 67 for 241Am as a function of Ca2+, from 0.2 to 0.002 M, respectively, 1.6 to 280 for 241Am as a function of Na+, 0.43 to 0.66 for 237Np as a function of Ca2+, and 0.16 to 0.25 for 237Np as a function of Na+ from 3.0 less than 0.015 M, respectively. For the Washington soil, Kd values were greater than 1200 for 241Am and ranged from 0.36 to 2.37 as a function of Ca2+ and from 3.19 to 3.90 for 237Np as a function of Na+ over the above concentration ranges, respectively. Kd values for 99Tc were essentially 0 at all NaHCO3 concentrations on the South Carolina subsoil

  10. Study of the functional characteristics of a NaI(Tl) scintillator gamma spectrometer

    Functional characteristics (resolution, stability, linearity, counting efficiency) of a NaI(Tl) scintillator gamma spectrometer were studied. Diagrams were plotted and several standard sources (241Am, 109Cd, 57Co, 137Cs, 54Mn, 22Na) with gamma energies ranging from 60 to 1275 KeV were used. (C.L.B.)

  11. Use of Hauser-V code for nuclear data evaluation

    This Statistical (HAUSER-FESHBACH Theory) optical model based code was used for calculating the fission cross sections for 239Pu and 241Am as a part of International Code Intercomparison exercise. The results submitted are compared with other eight different contributions

  12. Characterization and use of shadow cone in a calibration laboratory for neutron; Caracterizacion y empleo de conos de sombra en un laboratorio para calibracion neutronica

    Gallego Diaz, E.; Valle Diez, A. del; Lorente Fillol, A.; Vega Carrillo, H. R.

    2011-07-01

    We present the design, characterization and use of shadow cones neutron measurements of the Laboratory of Nuclear Engineering Department of the ETSII-UPM (LMN-UPM), with an irradiation room size 9 mx 16 mx 8 m in that used an {sup 2}41Am-Be source of 11 GBq (3 Ci).

  13. Measurement of the cross sections of the minor transactinium isotopes

    Measurements of neutron cross sections of the minor transactinium isotopes performed since the 1975 IAEA meeting on transactinium isotope nuclear data are reviewed. Some of the recent developments in experimental techniques are briefly described. As two specific examples measurements on 241Am and 230Th(n,f) are discussed in some detail

  14. Fuel-containing particles released from the fourth block of the Chernobyl NPP in soil samples of the Bryansk district

    Autoradiography is used to identify radioactive microparticles in the small soil fraction. Microparticles containing α-emitters are detected. Radiochemical and α-spectrometric methods revealed the nature of the α-tracks. The contents of Pu and 241Am in the studied sample are estimated. The data confirm the open-quotes Chernobyl originclose quotes of the contaminated Bryanski soil (Novozybkovsk region)

  15. Neutron spectra and dosimetric features of isotopic neutron sources: a review

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Martinez O, S. A., E-mail: fermineutron@yahoo.com [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte 39-115, 150003 Tunja, Boyaca (Colombia)

    2015-10-15

    A convenient way to produce neutrons is the isotopic neutron source, where the production is through (α, n), (γ, n), and spontaneous fission reactions. Isotopic neutron sources are small, easy to handle, and have a relative low cost. On the other hand the neutron yield is small and mostly of them produces neutrons with a wide energy distribution. In this work, a review is carried out about the the main features of {sup 24}NaBe, {sup 24}NaD{sub 2}O, {sup 116}InBe, {sup 140}LaBe, {sup 238}PuLi, {sup 239}PuBe, {sup 241}AmB, {sup 241}AmBe, {sup 241}AmF, {sup 241}AmLi, {sup 242}CmBe, {sup 210}PoBe, {sup 226}RaBe, {sup 252}Cf and {sup 252}Cf/D{sub 2}O isotopic neutron source. Also, using Monte Carlo methods, the neutron spectra in 31 energy groups, the neutron mean energy; the Ambient dose equivalent, the Personal dose equivalent and the Effective dose were calculated for these isotopic neutron sources. (Author)

  16. Summing coincidence errors using 152Eu lungs to calibrate a lung-counting system: are they significant?

    Kramer, Gary H; Lynch, Timothy; Lopez, Maria Antonia; Hauck, Barry M

    2004-02-01

    The use of a lung phantom containing 152Eu/241 Am activity can provide a sufficient number of energy lines to generate an efficiency calibration for the in vivo measurements of radioactive materials in the lungs. However, due to the number of energy lines associated with 152Eu, coincidence summing occurs and can present a problem when using such a phantom for calibrating lung-counting systems. A Summing Peak Effect Study was conducted at three laboratories to determine the effect of using an efficiency calibration based on a 152Eu/241 Am lung phantom. The measurement data at all three laboratories showed the presence of sum peaks. While one of the laboratories found only small biases (< 5%) when using the 152Eu/241 Am calibration, the other facilities noted up to 30% positive bias in the 140 keV to 190 keV energy range that prevents the use of the 152Eu/241 Am lung phantom for routine calibrations. Although manufactured by different vendors, the three facilities use similar types of germanium detectors (38 cm2 by 25 mm thick or 38 cm2 by 30 mm thick) for counting. These results underscore the need to evaluate the coincidence summing effect, which appear system dependent, when using a nuclide such as 152Eu for the calibration of low-energy lung counting systems and highlight the problem of using a general calibration curve in place of specific nuclide calibration factors. PMID:14744066

  17. Investigating the Inverse Square Law with the Timepix Hybrid Silicon Pixel Detector: A CERN [at] School Demonstration Experiment

    Whyntie, T.; Parker, B.

    2013-01-01

    The Timepix hybrid silicon pixel detector has been used to investigate the inverse square law of radiation from a point source as a demonstration of the CERN [at] school detector kit capabilities. The experiment described uses a Timepix detector to detect the gamma rays emitted by an [superscript 241]Am radioactive source at a number of different…

  18. Ionization cross section measurement of heavy atom L levels (Z>=72) with Americium 241 γ radiation at 59.6 keV

    The cross-sections for L X-ray production by the 59.6 keV γ radiation of 241Am have been measured for heavy elements (Z > 70). The L subshell ionization cross-sections have been calculated on the basis of these measurements

  19. The role of natural organic matter in the migration behaviour of americium in the Boom clay - Part II: analysis of migration experiments

    Full text of publication follows: In demonstrating the suitability of Boom Clay as a potential site for the disposal of radioactive waste in Belgium, the role of the relatively high amount of Natural Organic Matter (NOM) present in the Boom Clay on the mobility of critical radionuclides needs investigation. Trivalent actinides and lanthanides form strong complexes with humic substances. Complexation of these trivalent radionuclides with NOM present in the Boom Clay may have opposing effects. If complexed by the aqueous phase (mobile) NOM, radionuclide transport will be governed by the mobility of these dissolved radionuclide-NOM species. If complexed by the solid phase (immobile) NOM, migration will be retarded. One of the aims of the EC projects TRANCOM-Clay and TRANCOM-II was to investigate the role of mobile NOM as radionuclide carrier with the objective of deriving conceptual models that can be implemented in repository performance assessment (PA) models. A separate paper describes the results of column migration experiments involving the transport of 241Am-14C-NOM complexes through Boom Clay cores. This paper describes the transport model, POPCORN, that was developed to describe and evaluate the influence of NOM on radionuclide transport in clay, taking into account attachment/detachment rates of NOM to clay surfaces and the kinetics of RN complexation to, and destabilization from, NOM. The POPCORN model was used to evaluate diffusion experiments involving injection of 14C-labelled NOM in Boom Clay cores. Model fits were obtained by varying the rates of filtration of NOM by attachment to the surface of the clay matrix. POPCORN was then used to analyse the 241Am-14C-NOM migration experiments. The stability properties of the 241Am-NOM were characterised by kinetic constants, and good matches to the migration data were achieved for the experiments. The findings suggest that a small sub-population of the original 241Am-OM is the most stable, and that this sub

  20. Uptake of americium-241 by plants from contaminated Chernobyl exclusive zone test site soils

    Americium-241 was found to accumulate in soils and biological objects of the environment. Its concentration has increased many times after the Chernobyl disaster and can be expected to increase about 40 times in the future. This research concentrated on the contaminated exclusive Chernobyl zone polluted by trace radionuclides, their behavior and accumulation by various plant species. Special attention is devoted to the bioavailability of 241Am to the plants Galium rivale, G. tinctorium, G. aparine, G. intermedium, Berteroa incana, Artemisia absinthium, A. vulgaris, Centaurea borysthenica, C. arenaria, Cirsium arvense, Succissa pratensis, Solidago virgaurea, Linaria vulgaris, Lepidium ruderale, Stenactis annua, Veronica maxima, Verbascum lychnitis, Euphorbia cyparissias, Genista tinctoria, Erigeron canadensis, Oenothera biennis, Betula pendula and Quercus robur, which were collected from the Chernobyl, Kopachi, and Yanov districts. The plant samples of Oenothera biennis, Betula pendula and Quercus robur were collected from the Yanov district, where the soil contamination by 241Am and 137Cs was at the level of 660 and 27 MBq/m2, respectively. Gamma spectroscopy and radiochemical methods were used to estimate the activity concentration of 137Cs, 90Sr, 238Pu, 239+240Pu, 241Am. The radionuclides were measured in the dry green mass of the plant samples and in the dry soils. The contamination of the Oenothera biennis, Betula pendula and Quercus robur samples by 137Cs was (5.8±1,5)x106, (7.4±1.1)x105, and (2.6±0.2)x106 Bq/kg dry mass, respectively, and contamination by 241Am was 47±5, 45±3 and 3.2±0.2 Bq/kg, respectively. The soil-to-plant transfer ratio for 137Cs ranged lay within the interval of 0.2 to 0.03 Bq/kg : Bq/m2, the the transfer ratio for 241Am did not exceed 7x10-5 Bq/kg : Bq/m2. The coefficient of the relative contents of the 241Am/239+240Pu radionuclides in the various plant samples varied from 3.2 to 8.3, while for soil from the Yanov district this

  1. Uptake, depuration, and radiation dose estimation in zebrafish exposed to radionuclides via aqueous or dietary routes

    Understanding uptake and depuration of radionuclides in organisms is necessary to relate exposure to radiation dose and ultimately to biological effects. We investigated uptake and depuration of a mixture of radionuclides to link bioaccumulation with radiation dose in zebrafish, Danio rerio. Adult zebrafish were exposed to radionuclides (54Mn, 60Co, 65Zn, 75Se, 109Cd, 110mAg, 134Cs and 241Am) at tracer levels (-1) for 14 d, either via water or diet. Radioactivity concentrations were measured in whole body and excised gonads of exposed fish during uptake (14 d) and depuration phases (47 d and 42 d for aqueous and dietary exposures respectively), and dose rates were modelled from activity concentrations in whole body and exposure medium (water or diet). After 14-day aqueous exposure, radionuclides were detected in decreasing activity concentrations: 75Se > 65Zn > 109Cd > 110mAg > 54Mn > 60Co > 241Am > 134Cs (range: 175-8 Bq g1). After dietary exposure the order of radionuclide activity concentration in tissues (Bq g-1) was: 65Zn > 60Co > 75Se > 109Cd > 110mAg > 241Am > 54Mn > 134Cs (range: 91-1 Bq g-1). Aqueous exposure resulted in higher whole body activity concentrations for all radionuclides except 60Co. Route of exposure did not appear to influence activity concentrations in gonads, except for 54Mn, 65Zn, and 75Se, which had higher activity concentrations in gonads following aqueous exposure. Highest gonad activity concentrations (Bq g-1) were for 75Se (211), 109Cd (142), and 65Zn (117), and highest dose rates (μGy h-1) were from 241Am (aqueous, 1050; diet 242). This study links radionuclide bioaccumulation data obtained in laboratory experiments with radiation dose determined by application of a dosimetry modelling tool, an approach that will enable better linkages to be made between exposure, dose, and effects of radionuclides in organisms. - Highlights: →Uptake and depuration of radionuclides in zebrafish exposed via water or diet.

  2. Accumulation of transuranic elements in the aquatic biota of the Belarusian sector of contaminated area near the Chernobyl nuclear power plant - Accumulation of transuranic elements in aquatic biota of Belarusian sector of contaminated area of Chernobyl nuclear power plant

    Golubev, Alexander; Mironov, Vladislav [International Sakharov Environmental University. Box 220070, 23 Dolgobrodskaya Street, Minsk, 220070 (Belarus)

    2014-07-01

    The evolution of nuclear contamination of Belarus territory after Chernobyl accident includes the four stages: 1. Iodine-neptunium stage, caused mainly by short-lived radionuclides {sup 131}I, {sup 239}Np and others with a half-life period of several weeks; II. Intermediate stage, caused by radionuclides with a half-life period of a year ({sup 144}Ce, {sup 106}Ru, {sup 134}Cs, etc.); III. Strontium-cesium stage, caused by {sup 90}Sr and {sup 137}Cs with a half-life period of about 30 years; IV. Plutonium-americium, caused by long-lived α-emitting radionuclides {sup 241}Am (period of half-life of 432 years) and {sup 239+240}Pu, having high radio and chemo-toxicity. According to forecasts, activity of {sup 241}Am to 2050 year will increase by 2.5 times and it will be the most important dose-related factor for the aquatic biota within the Chernobyl accident zone. In 2002 - 2008 years we have studied the accumulation of trans-uranic elements (TUE, {sup 241}Am, {sup 239+240}Pu) in basic components of water body ecosystems within the Chernobyl zone - non-flowing Perstok Lake, weak-flowing Borschevka flooding and small Braginka River. Among investigated components are water, bottom sediments, submerged macrophytes (Ceratophyllum submersum, Hydrocharis morsus-ranae, Lemna minor, Nuphar lutea, Stratiotes aloides), emergent macrophytes (Typha spp.), shellfish and fish. In the soil cover in the vicinity of the Perstok Lake activity of {sup 241}Am at present is equivalent to 300 - 600 Bq.kg{sup -1}, that is the basic source of its income to the lake. Radionuclides mobility in the water environment is higher than in the soil, that facilitates the rapid incorporation of {sup 241}Am to the trophic nets of water bodies and its removal by near-water animals in the terrestrial biotopes, including outside Chernobyl zone. Thus, the activity of {sup 241}Am in bottom sediments in the Perstok Lake and Borschevka flooding in 2008 year reach respectively 324 and 131 Bq.kg{sup -1}, and the

  3. Accumulation of transuranic elements in the aquatic biota of the Belarusian sector of contaminated area near the Chernobyl nuclear power plant - Accumulation of transuranic elements in aquatic biota of Belarusian sector of contaminated area of Chernobyl nuclear power plant

    The evolution of nuclear contamination of Belarus territory after Chernobyl accident includes the four stages: 1. Iodine-neptunium stage, caused mainly by short-lived radionuclides 131I, 239Np and others with a half-life period of several weeks; II. Intermediate stage, caused by radionuclides with a half-life period of a year (144Ce, 106Ru, 134Cs, etc.); III. Strontium-cesium stage, caused by 90Sr and 137Cs with a half-life period of about 30 years; IV. Plutonium-americium, caused by long-lived α-emitting radionuclides 241Am (period of half-life of 432 years) and 239+240Pu, having high radio and chemo-toxicity. According to forecasts, activity of 241Am to 2050 year will increase by 2.5 times and it will be the most important dose-related factor for the aquatic biota within the Chernobyl accident zone. In 2002 - 2008 years we have studied the accumulation of trans-uranic elements (TUE, 241Am, 239+240Pu) in basic components of water body ecosystems within the Chernobyl zone - non-flowing Perstok Lake, weak-flowing Borschevka flooding and small Braginka River. Among investigated components are water, bottom sediments, submerged macrophytes (Ceratophyllum submersum, Hydrocharis morsus-ranae, Lemna minor, Nuphar lutea, Stratiotes aloides), emergent macrophytes (Typha spp.), shellfish and fish. In the soil cover in the vicinity of the Perstok Lake activity of 241Am at present is equivalent to 300 - 600 Bq.kg-1, that is the basic source of its income to the lake. Radionuclides mobility in the water environment is higher than in the soil, that facilitates the rapid incorporation of 241Am to the trophic nets of water bodies and its removal by near-water animals in the terrestrial biotopes, including outside Chernobyl zone. Thus, the activity of 241Am in bottom sediments in the Perstok Lake and Borschevka flooding in 2008 year reach respectively 324 and 131 Bq.kg-1, and the activity of 241Am in macrophytes of the Perstok Lake at the same year was 1,0 - 3,7 Bq.kg-1. In

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

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

  5. Role of natural dissolved organic compounds in determining the concentrations of americium in natural waters

    Concentrations of 241Am, both in solution and bound to suspended particulate matter, have been measured in several North American lakes. Dissolved concentrations vary from 0.4 μBq/L to 85 μBq/L. The 241Am in these lakes originated solely from global fallout and hence entered all lakes in the same physiocochemical form. The observed differences in solubility behavior must, therefore, be attributable to chemical and/or hydrological differences among the lakes. Concentrations of dissolved 241Am are highly correlated with the corresponding concentrations of /sup 239, 240/Pu(III,IV), suggesting that a common factor is responsible for maintaining both in solution. The K/sub D/ values for 241Am and /sup 239, 240/Pu(III,IV) are highly correlated with the concentrations of dissolved organic carbon (DOC) in the waters, suggesting that the common factor is the formation of soluble complexes with natural DOC for both elements. This hypothesis was tested in a series of laboratory experiments in which the DOC from several of the lakes was isolated by ultrafiltration. Plots of K/sub D/, as a function of DOC concentration, show K/sub D/ to be very high (approx.106) at low DOC concentrations. Above critical concentrations (a few mg/L DOC) the K/sub D/ values begin a progressive decrease with increasing DOC. We conclude that in most surface waters, the dissolved 241Am concentration is regulated by an adsorption/desorption equilibrium with the sediments (and suspended solids) and the value of K/sub D/ that characterizes this equilibrium is largely determined by the concentration of natural DOC in the water. 11 refs., 3 figs., 2 tabs

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

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

  7. Discoveries of Elements 113, 115 and 117

    Discovery of two isotopes of the new element 117 in the 249Bk + 48Ca reaction is described. A new 243Am + 48Ca experiment was carried out to firmly establish the discoveries of new elements 115 and 113. A total of thirty one decay chains of 288115 are now observed in the Am reaction. In addition, four new decay chains are assigned to 289115.

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

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

    2016-05-01

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

  9. Theoretical and experimental study of the bio-geochemical behaviour of americium 241 in simplified rhizosphere conditions. Application to a calcareous agricultural soil

    Americium 241, is one of the most radio-toxic contaminant produced during the nuclear fuel cycle. It can be found in all environmental compartments, in particular the soils. The main goals of this study are to identify, quantify and model the effect of the main factors controlling the mobility of 241Am in the rhizosphere and the agricultural soils. The physico-chemical parameters of the soil and of the soil solution, the potential role of microorganisms on the sorption-desorption processes, and the speciation of americium in solution have been more particularly studied. 241Am remobilization has been studied at the laboratory using leaching experiments performed in controlled conditions on reworked calcareous soils artificially contaminated with 241Am. The soil samples have been washed out in different hydrodynamic conditions by solutions with various compositions. The eluted solution has been analyzed (pH, conductivity, ionic composition, Fetot, organic acids, 241Am) and its bacterial biomass content too. The overall results indicate that 241Am remobilization is contrasted and strongly linked with the condition under study (pH, ionic strength, glucose and/or citrate concentration). Therefore, a solution in equilibrium with the soil or containing small exudate concentrations (10-4 M) re-mobilizes only a very small part of the americium fixed on the solid phase. The desorption of 241Am corresponds to a solid/liquid coefficient of partition (Kd) of about 105 L.kg-1. A significant addition of glucose induces an important dissolution of soil carbonates by the indirect action of microorganisms, but does not significantly favor the 241Am remobilization. On the other hand, the presence of strong citrate concentrations (≥ 10-2 M) allows 300 to 10000 time greater re-mobilizations by the complexing of 241Am released after the dissolution of the carrying phases. Finally, the colloidal transport of 241Am has been systematically observed in a limited but significant extend and

  10. Proliferation Resistant Fuel for Pebble Bed Modular Reactors

    Proliferation of nuclear weapons produced with power reactors plutonium has always been amajor problem of the nuclear energy industry. This includes the PebbleBed Modular Reactor(PBMR), which is a specific design of a GenIV High-Temperature Reactor (HTR), mainly due to its online refueling feature, which may be misused for the production of weapons gradeplutonium. A promising approach toward preventing the proliferation of power reactorplutoniumis to denaturate the plutonium by increasing the ratio of 238Pu to total Pu in the spentfuel(1). The 238Pu isotope is characterized by a high heat rate (approximately 567 W/kg) due to thealpha decay of the 238Pu with half-life of 87.74 yr, in addition to its high spontaneous fissionneutron emission, which is higher than that of 240Pu. Thus, the presence of 238Pu in Pu considerably complicates the design and construction of nuclear weapons based on Pu, owing tothese characteristics of 238Pu. Recent papers(2,3) show that a Pu mixture is proliferation resistant given that the weight ratio of 238Pu to Pu is larger than 6%. In this paper we have studied afeasible technique for ensuring that the 238Pu to Pu ratio, in the Pu produced in PBMR, is larger than 6% during the entire fuel cycle. Contamination of the spent fuel with 238Pu may be achieved by doping the nuclear fuel witheither 241Am or 237Np(4-13). The 238Pu isotope is obtained from both 241Am and 237Np by a neutron-capture reaction and the subsequent decay of the reaction products(13).The 237Np isotopeis by itself a potential weapons grade material. However, its large critical mass of 57±4 kg(14) andthe difficulty of extracting it from irradiated fuel elements make it impractical for weapons purposes. On the other hand, the critical mass of 241Am is smaller, i.e. 34 to 45 kg. However, withdecay heat production of 114W/kg, the critical mass becomes a heat source of 3.9 to 5.1 KW,which makes 241Am unsuitable for weapons applications(3). As a result, it is a non

  11. Placental transfer of americium and plutonium in mice

    Actinide element release to the environment and subsequent transfer through food chains to pregnant women may present a radiation hazard to fetuses in utero. To measure americium incorporation, four groups of pregnant mice were intravenously dosed with four concentrations of 243Am citrate in late pregnancy. Concentrations of 243Am in fetuses, placentas, and maternal femur, liver, carcass and pelt were determined 48 hr after injection. Doses were chosen so that the number of atoms of 243Am in each injected dose was equal to the number of atoms of 239Pu used in an earlier study of transplacental movement. Results indicate that, atom for atom, americium is incorporated into fetal tissue in lesser amounts (10-25 times) than is plutonium when intravenously administered to pregnant mice in equal atom amounts. Tissue analyses indicated that, at low dose levels, the average fraction of the dose incorporated into the fetuses decreased as the dose to the pregnant mouse was increased. A similar pattern was noted for placentas and maternal femurs. Data indicate that one must make extrapolations from low dose data only to make reasonable and realistic estimates of the transplacental movement and fetal incorporation of environmental levels of actinide elements in man and other species. (author)

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

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

  13. ZZ MCB-JEF2.2, MCB Continuous-Energy Neutron Cross Section Libraries for Temperatures from 300 to 1800 K

    -154, Eu-155, Eu-156, Eu-157, Gd-154, Gd-155, Gd-156, Gd-157, Gd-158, Gd-160, Tb-159, Tb-160, Dy-160, Dy-161, Dy-162, Dy-163, Dy-164, Ho-165, Er-166, Er-167, Lu-175, Lu-176, Hf-174, Hf-176, Hf-177, Hf-178, Hf-179, Hf-180, Ta-181, Ta-182, W-182, W-183, W-184, W-186, Re-185, Re-187, Au-197, Pb-nat., Bi-209, Th-230, Th-232, Pa-231, Pa-233, U-232, U-233, U-234, U-235, U-236, U-237, U-238, Np-237, Np-238, Np-239, Pu-236, Pu-237, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242, Pu-243, Pu-244, Am-241, Am-242, Am-242m, Am-243, Cm-241, Cm-242, Cm-243, Cm-244, Cm-245, Cm-246, Cm-247, Cm-248, Bk-249, Cf-249, Cf-250, Cf-251, Cf-252, Cf-253, Es-253. Temperatures: 300 K, 600 K, 900 K, 1200 K, 1500 K, and 1800 K. Origin: JEF-2.2. 2 - Methods: The library was generated using the NJOY processing code. An example of the input data is provided

  14. Design and Thermal Distribution of Microwave Spiral Antenna

    Spiral microwave antennas have been developed and measure the thermal distribution in agar phantom. The design has been configured in three types, 3 cm f applicator with 24.5 cm length (A type), 4 cm f with 12.2 cm (B type) and 6 cm f with 24.5 cm length (C type). The relative specific absorption rate (SAR) measured in phantom have been used to estimate the depth and profile of effective heating. The applicator of copper antenna with 4 cm f diameter and 12.2 cm length (B type) has the most homogeneous (FWHM=3.5 cm) and heating into deep with (Deff=4cm)

  15. Low and high dose measurement by Agfa personal monitoring film and FD-III-B badge dosimeter system

    This paper presents the measurement of the dose equivalent Hp(10) to low (0.005-1) mSv and high (20-1000) mSv doses by exposure at 241Am and 173Cs radiation sources of the halide film with FB-III-D dosimeter system. Accuracy of measurements, standard error of the dose mean value (SEM) and some comments about ability to reread of dosimetric films were determined. A good accuracy was obtained over the important dose ranges. In the low dose range, under 0.1 mSv, the SEM values of the 241Am doses, recorded on the film under plastic filter, are between -21.36% and +47.51%. For 0.1-500 mSv 137Cs dose range the SEM values are from -9.55% to +7.24%.

  16. Comments on chelation therapy

    The primary purpose of actinide chelation is to decrease the risk from radiation-induced cancer. While occupational exposures in the past have mainly involved low specific activity 239Pu, future exposures will increasingly involve high specific activity plutonium, americium, and curium - all of which clear more rapidly from the lung. This will tend to shift the cancer risk from lung to bone and liver. Although therapy with Ca- or Zn-DTPA rapidly removes 241Am from the canine, the sub-human primate, and the human liver, improved methods for removal from bone and lung are needed. DTPA can remove 241Am more easily from the growing skeleton of a child than from the mature skeleton of an adult. Investigators at Karlsruhe are developing chelation agents for oral administration and are investigating the reduction in local dose to bone resulting from chelation therapy

  17. Solubility of americium collected on an aerosol filter

    Kinetics of dissolution of undefined americium aerosol in simulated serum ultrafiltrate was studied. 241Am was present in aerosol collected at a workplace, where an intake of 241Am had occurred formerly. Dissolution experiments in four parts of an aerosol filter were carried out either in ambient air or under CO2 and pH was kept within physiological range. Two?phase kinetics was found in both cases with dissolution half?times for rapid and slow phases ranging from 0.16 to 0.23 d and from 150 to 500 d, respectively. Regardless data dispersion, found half?times justify use of class M model in intake assessment. (author)

  18. 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

  19. Preliminary experiment of the controllable Am-Be neutron source based on composite polymeric membrane

    A controllable Am-Be neutron source was designed based on a hamburger structure including two Be pallets and a composite polymeric membrane carrying 241Am. The composite polymeric membrane was made of polyvinylidene fluoride (PVDF) and polyvinyl alcohol (PVA). PVDF polymeric membrane was used as the base film to load the mixed Am(NO3)3-PVA solution, which was coated on the PVDF polymeric membrane. The thickness of two layers was both about 5 μm. The correlative calculations were performed using the Geant4 code. A piece of composite membrane loading 241Am of 2.13 × 106 Bq was placed in the middle of two Be pallets just like a hamburger. Neutrons were produced continuously until the composite membrane was separated from Be pallets. The neutron yield of the controllable hamburger neutron source was measured as 54 n/(106α), which was 15.6 % lower than the calculation value. (author)

  20. Minior Actinide Doppler Coefficient Measurement Assessment

    Nolan E. Hertel; Dwayne Blaylock

    2008-04-10

    The "Minor Actinide Doppler Coefficient Measurement Assessment" was a Department of Energy (DOE) U-NERI funded project intended to assess the viability of using either the FLATTOP or the COMET critical assembly to measure high temperature Doppler coefficients. The goal of the project was to calculate using the MCNP5 code the gram amounts of Np-237, Pu-238, Pu-239, Pu-241, AM-241, AM-242m, Am-243, and CM-244 needed to produce a 1E-5 in reactivity for a change in operating temperature 800C to 1000C. After determining the viability of using the assemblies and calculating the amounts of each actinide an experiment will be designed to verify the calculated results. The calculations and any doncuted experiments are designed to support the Advanced Fuel Cycle Initiative in conducting safety analysis of advanced fast reactor or acceoerator-driven transmutation systems with fuel containing high minor actinide content.

  1. Detecting energy dependent neutron capture distributions in a liquid scintillator

    Balmer, Matthew J.I., E-mail: m.balmer@lancaster.ac.uk [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Gamage, Kelum A.A. [Department of Engineering, Lancaster University, LA1 4YR (United Kingdom); Taylor, Graeme C. [Neutron Metrology Group, National Physical Laboratory, Teddington, TW11 0LW (United Kingdom)

    2015-03-11

    A novel technique is being developed to estimate the effective dose of a neutron field based on the distribution of neutron captures in a scintillator. Using Monte Carlo techniques, a number of monoenergetic neutron source energies and locations were modelled and their neutron capture response was recorded. Using back propagation Artificial Neural Networks (ANN) the energy and incident direction of the neutron field was predicted from the distribution of neutron captures within a {sup 6}Li-loaded liquid scintillator. Using this proposed technique, the effective dose of {sup 252}Cf, {sup 241}AmBe and {sup 241}AmLi neutron fields was estimated to within 30% for four perpendicular angles in the horizontal plane. Initial theoretical investigations show that this technique holds some promise for real-time estimation of the effective dose of a neutron field.

  2. Energetic resolution study on pure and CsBr doped CsI under gamma excitations and alpha particles

    Pure and doped CsI crystals were grown using the Bridgman technique. Bromine was the doping element which was studied in the range of 1.5x10-1 M to 10-2 M. The distribution of the doping element at crystalline volume was determined by neutron activation. Concerning gamma radiation response it was carried out measurements to evaluate the developed scintillators in the energy range of 350 keV to 1330 keV. For alpha particles measurements an 241Am source was used with 5.54 MeV energy. The resolution of 3.7% was obtained for the CsI:Br 10-2 M crystal, when excited with alpha particles from an 241Am source. For CsI:Br 10-1 M crystal 9.1% resolution was obtained when excited with gamma radiation from 22Na source, with 1275 keV energy. (author)

  3. Mutual separation of americium(III) and europium(III) using glycolamic acid and thioglycolamic acid

    The extractants, bis(2-ethylhexyl)diglycolamicacid (HDEHDGA) and bis(2-ethylhexy)thiodiglycolamic acid (HDEHSDGA) were synthesized and characterized by 1H and 13C NMR, mass and IR spectroscopy. The extraction behaviour of (152+154)Eu(III) and 241Am(III) from nitric acid medium by a solution of HDEHDGA (or HDEHSDGA) in n-dodecane (n-DD) was studied for the mutual separation of actinides and lanthanides. The effect of various parameters such as the pH, concentrations of HDEHDGA, HDEHSDGA, sodium nitrate, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) and diethylenetriaminepentaacetic acid (DTPA) on the separation factor (SF) of americium(III) over europium(III) and vice versa was studied, and the conditions needed for the preferential separation were optimised. The results show that HDEHDGA exhibits higher extraction for (152+154)Eu(III) and HDEHSDGA shows the superior selectivity for 241Am(III). (orig.)

  4. The comparison of four neutron sources for Prompt Gamma Neutron Activation Analysis (PGNAA) in vivo detections of boron

    A Prompt Gamma Ray Neutron Activation Analysis (PGNAA) system, incorporating an isotopic neutron source has been simulated using the MCNPX Monte Carlo code. In order to improve the signal to noise ratio different collimators and a filter were placed between the neutron source and the object. The effect of the positioning of the neutron beam and the detector relative to the object has been studied. In this work the optimisation procedure is demonstrated for boron. Monte Carlo calculations were carried out to compare the performance of the proposed PGNAA system using four different neutron sources (241Am/Be, 252Cf, 241Am/B, and DT neutron generator). Among the different systems the 252Cf neutron based PGNAA system has the best performance. (author)

  5. Experimental investigation of mass efficiency curve for alpha radioactivity counting using a gas-proportional detector

    Gross α counting of evaporated water residues offers a simple method for screening α radioactivity in water for both public health and emergency purposes. The evaporation process for water has been improved by using a combination of roughening of the surface of counting planchettes, two-stage evaporation, and temperature-controlled block heating. The efficiency of the gas-proportional detector for α-particle detection in water residues was studied as a function of sample mass-thickness in the range between 0.1 and 13 mg cm-2. The effect of α energy on the efficiency, as well as moisture absorption on the samples, were studied using 230Th, 238U, 239Pu, 241Am, and 244Cm radionuclides. Also, α-to-β crosstalk was investigated as a function of sample mass for 230Th, 239Pu, 210Po, 241Am, and 244Cm. The improved method can also be applied for gross α detection in biological fluids

  6. The 1976 Hanford Americium Accident: Then and Now

    Carbaugh, Eugene H.

    2013-10-02

    The 1976 chemical explosion of an 241Am ion exchange column at a Hanford Site waste management facility resulted in the extreme contamination of a worker with 241Am, nitric acid and debris. The worker underwent medical treatment for acid burns, as well as wound debridement, extensive personal skin decontamination and long-term DTPA chelation therapy for decorporation of americium-241. Because of the contamination levels and prolonged decontamination efforts, care was provided for the first three months at the unique Emergency Decontamination Facility with gradual transition to the patient’s home occurring over another two months. The medical treatment, management, and dosimetry of the patient have been well documented in numerous reports and journal articles. The lessons learned with regard to patient treatment and effectiveness of therapy still form the underlying philosophy of treatment for contaminated injuries. Changes in infrastructure and facilities as well as societal expectations make for interesting speculation as to how responses might differ today.

  7. Alpha-spectrometry measurement of Am and Cm at trace levels in environmental samples using extraction chromatography

    Various anthropogenic sources contribute to the presence of americium and curium isotopes in environmental samples. Incomplete radiochemical separations led to electrodeposited sources containing stable element impurities increasing auto-absorption effects. Other radioactive elements, such as 227Ac and its daughters, interfered with 241Am and 243,244Cm emissions. These impurities are now completely eliminated using a Tru-Spec trademark column. Very low levels of 241Am and 243,244Cm in environmental samples (i.e. algae, mussels, sediment, etc.) from the Channel and the Rhone river, including its estuary, were investigated using a routine radiochemical process and measurement at levels as low as achievable with state of the art measuring technology. (orig.)

  8. Alpha-n and spontaneous fission sources and spectra from individual plutonium isotopes in PuF4 and PuO2

    Plutonium-containing compounds vary widely in isotopic content, and as a result, the dose as function of isotopic content also varies considerably. Determination of the dose from neutrons, decay and capture gammas from plutonium in the form of compounds thus requires that the spontaneous fission and (α,n) source and spectra from each individual isotope be known. To facilitate dose calculations from plutonium-containing compounds, we have calculated the spontaneous fission and (α,n) sources and spectra for 1 g of each of the plutonium isotopes in the form of either PuF4 or PuO2. As 241Am is often a component in a mixture of plutonium isotopic compounds, the source and spectra from 1 g of 241Am mixed with PuF4 or PuO2 has also been determined. Using these results, the neutron source and spectra may be determined for any sample composition. 2 refs., 3 tabs

  9. Brazilian two-component TLD albedo neutron individual monitoring system

    Since 1983, Instituto de Radioprotecao e Dosimetria, Brazil, uses a TLD one-component albedo neutron monitor, which has a single different calibration factor specifically for each installation type. In order to improve its energy response, a two-component albedo monitor was developed, which measure the thermal neutron component besides the albedo one. The two-component monitor has been calibrated in reference neutron fields: thermal, five accelerator-produced monoenergetic beams (70, 144, 565, 1200 and 5000 keV) and five radionuclide sources (252Cf, 252Cf(D2O), 241Am-Be, 241Am-B and 238Pu-Be) at several distances. Since January 2008, mainly Brazilian workers who handle neutron sources at different distances and moderation, such as in well logging and calibration facilities are using it routinely.

  10. Determination of Energy and Angular Response of an Albedo Neutron Personal Dosemeter

    The result of the determination of energy and angular response for the albedo neutron personal dosemeter used by CPHR, is described. The dosemeters consist of two pairs of LiF detectors (6LiF+7LiF) separated by a piece of boron-loaded plastic. For the study, the dosemeters were irradiated in three mixed neutron-gamma fields (thermal neutrons, moderated 241Am-Be and 241Am-Be) and at two incidence angles of radiation (0 deg. and 60 deg. ). The variation of the sensibility at different neutron spectra and incidence angles of radiation was determined. The methodology of dose evaluation, applying the obtained coefficients, was established. (author)

  11. US Mussel Watch Program: Transuranic element data from Woods Hole Oceanographic Institution 1976-1983. Technical report

    Bivalves (Mytilus edulis, Mytilus californianus, Crassostrea virginica and Ostrea equestris) were collected once per year during 1976, 1977, and 1978 along the United States coast and analyzed for (239,240)Pu, (241)Am and (137)Cs as part of the U.S. Mussel Watch program. Monthly samples were collected during 1976-1980 from Narragansett Bay, Rhode Island and Bodega Head, California and analyzed for (239,240)Pu, (241)Am, and (137)Cs. There is no evidence in the data for systematic regional or local elevated concentrations of radionuclides as a result of releases from the nuclear fuel cycle. Monthly fluctuations in radionuclide concentrations in the Narragansett Bay mussels appear to be primarily influenced by spawning

  12. Measurements of the neutron capture cross sections and incineration potentials of minor-actinides in high thermal neutron fluxes: Impact on the transmutation of nuclear wastes

    This thesis comes within the framework of minor-actinide nuclear transmutation studies. First of all, we have evaluated the impact of minor actinide nuclear data uncertainties within the cases of 241Am and 237Np incineration in three different reactor spectra: EFR (fast), GT-MHR (epithermal) and HI-HWR (thermal). The nuclear parameters which give the highest uncertainties were thus highlighted. As a result of fact, we have tried to reduce data uncertainties, in the thermal energy region, for one part of them through experimental campaigns in the moderated high intensity neutron fluxes of ILL reactor (Grenoble). These measurements were focused onto the incineration and transmutation of the americium-241, the curium-244 and the californium-249 isotopes. Finally, the values of 12 different cross sections and the 241Am isomeric branching ratio were precisely measured at thermal energy point. (author)

  13. Sorption of americium in tuff and pure minerals using synthetic and natural groundwaters

    The distribution of Am between selected solid and liquid phases has been studied using initial 241Am solutions with a molarity smaller than 1 x 10-11. The synthetic and natural groundwaters used have pH values in the 7--8 range and a total alkalinity of approximately 1 mN which is mainly due to bicarbonate. Mass spectrometric isotope dilution was utilized to determine the amount of Am in the solution phase initially and after equilibrium was attained. Using this sensitive technique, 7 x 108 atoms of 241Am were accurately measured. Our results indicate that the percent of Am lost to the walls of the container in the absence of geologic material varies from 35 to 84. The Am sorption coefficient determined is on the order of 103 ml/g for clinoptilolite, 104 ml/g for tuff consisting mainly of alkali feldspar and cristobalite, and 105 ml/g for romanechite. 12 refs

  14. Transuranic elements and strontium-90 in samples from forests in Poland

    Enhanced levels of non-volatile nuclides;141,144Ce, 95Zr, 95Nb, 103,106Ru, 238,239,240,241Pu, 241Am, 242,243,244Cm and 154,155Eu were observed in the samples from north-western Poland. This was considered to be a result of finding in sample ''hot particle''. Investigations conducted in the Institute of Nuclear Physics allowed us to conclude that on this area a non typical isotopic composition of Chernobyl fallout was very common. The enhanced activities (up to 100% above the global fallout value) of 90Sr, 238,239,240Pu and 241Am were observed. The presence of 243,244Cm and 154,155Eu was confirmed. It seems that the quasi-continuous fallout of huge numbers of small 'hot particles' occurred there from the high altitude radioactive cloud, which moved toward Scandinavia on 26-th of April, 1986. (author)

  15. Study of commercial Si-PIN photodiode as an x-ray detector

    Two commercial Si-PIN photodiode were evaluated as a low cost X-ray detector in conjunction with forward biased FET preamplifiers. Evaluation was done at room temperature and at a temperature of about -10degC using X-ray spectroscopy amplifier with 241Am radio active source. The results shows 700 eV full width at half maximum for 241Am γ-ray (59.5 keV) with S5821-02 from Hamamatsu Photonics at low temperature and 800 eV with S1722-02 at the same conditions. The S1722-02 photodiode showed almost flat response up to 20 keV X-ray energy. The improvement of photodiode and FET cooling system and proper selection of FET will be expected to show better resolution. (author)

  16. Am-241 remobilization in a calcareous soil under simplified rhizospheric conditions studied by column experiments

    The effects of simplified rhizospheric conditions on the leaching of 241Am from a calcareous soil, freshly contaminated, were investigated in batch and column experiments. Glucose and/or citrate were used as artificial exudate solutions at concentrations ranging from 10-4 to 10-2 mol dm-3. Am desorption, expressed in terms of distribution coefficients, varied from Kd > 104 dm3 kg-1 corresponding to a majority of experimental conditions, to Kd ≤ 102 dm3 kg-1 when citrate combined or not with glucose was used at ≥10-2 mol dm-3. Soil columns revealed successive steady states coupled with transitory episodes, the latter represented up to 90% of the total Am release. 241Am fractions with different behaviours were thus highlighted in columns whereas batch only accounted for highest Am mobile fractions. The implications of the different processes are discussed in terms of modelling approach and risk assessment

  17. Management of decontamination solution arising from Cerium redox process

    This paper describes the recovery of Pu from decontamination stream generated from Cerium Redox Process meant for decontamination of contaminated metallic wastes. Extraction of Pu is carried out using PUREX solvent after reducing it to tetravalent state which is subsequently stripped using hydroxylamine nitrate and nitric acid mixture. Raffinate from this step containing Ce3+, 241Am and corrosion products is subjected to ozonisation wherein Ce3+ is oxidized to Ce4+. Quantitative extraction of Ce is achieved by PUREX solvent in second cycle which is stripped using a mixture of NaNO2 and HNO3. Raffinate from this step contains 241Am and corrosion product which is removed by solvent extraction using TEHDGA. The final alpha lean waste can be managed by cementation. (author)

  18. Coincidence system for the absolute measurement of radionuclides activity using a liquid scintillator

    A system for the standartization of radioisotopes activity using liquid scintillator detector was developed. The system was set up at Nuclear Metrology Laboratory - L.M.N. (Nuclear Physics Division - IEA). The system performance was checked by absolute activity measurements for two radioisotopes, 60Co and 241Am. The activities were determined by the 4π(α, β-γ) coincidence method. An accuracy of the order of 99,8% was obtained. The results for 60Co were compared with those obtained by 4πβ-γ coincidence method using a proportional counter at L.M.N., while the results for 241Am were compared with those obtained through the linear extrapolation method using the same liquid scintillator. Compared to other systems, the advantages of this one are the simplicity and the short time spent in the sample preparation, and the negligible self-absorption. (Author)

  19. Measurements of the neutron capture cross sections and incineration potentials of minor-actinides in high thermal neutron fluxes: Impact on the transmutation of nuclear wastes; Mesures des sections efficaces de capture et potentiels d'incineration des actinides mineurs dans les hauts flux de neutrons: Impact sur la transmutation des dechets

    Bringer, O

    2007-10-15

    This thesis comes within the framework of minor-actinide nuclear transmutation studies. First of all, we have evaluated the impact of minor actinide nuclear data uncertainties within the cases of {sup 241}Am and {sup 237}Np incineration in three different reactor spectra: EFR (fast), GT-MHR (epithermal) and HI-HWR (thermal). The nuclear parameters which give the highest uncertainties were thus highlighted. As a result of fact, we have tried to reduce data uncertainties, in the thermal energy region, for one part of them through experimental campaigns in the moderated high intensity neutron fluxes of ILL reactor (Grenoble). These measurements were focused onto the incineration and transmutation of the americium-241, the curium-244 and the californium-249 isotopes. Finally, the values of 12 different cross sections and the {sup 241}Am isomeric branching ratio were precisely measured at thermal energy point. (author)

  20. Measurement of fission cross sections and fragment angular distributions using solid state track detectors

    Fission cross sections and angular distributions of fission fragments from fissions induced by 14.1 and 15.8 MeV neutrons, respectively, in 232Th, 231Pa, 233U, 235U, 238U, 237Np, 239Pu and 241Am have been studied using Lexan plastic track detectors. A novel experimental set-up evolved from considerations of neutron economy allows simultaneous measurement of angular distribution of fission fragments from five independently fissioning nuclides at a time. The data on angular anistropy were analysed in the perspective of different chances of fissions taking place simultaneously in this energy region. Third-chance fission thresholds for 231Pa and 241Am were estimated from the measured anisotropy values to be 13.2 and 11.1 MeV, respectively. (author)

  1. Nuclear and Physical Methods of Control For soil and Near-ground Air Contamination With Plutonium and Americium-241 in Belarus

    As a result of the Chernobyl NPP accident considerable territories of Belarus have been contaminated with Pu and 241Am. The absence of instrumental techniques for a direct analysis of transuranium elements (TUE) in the objects of the environment has made the using of laborious radiochemical methods inevitable what, in its turn, has limited a necessary scale of investigations on TUE problem. The paper presents the more cheap and express instrumental nuclear and physical techniques for Pu and 241Am analysis in soils and near-ground layer of air having been developed at the Institute of Power Engineering Problems / National Academy of Sciences of Belarus (IPEP NASB), as well as some results having been obtained using these techniques

  2. Absolute measurement of neutron source emission rate with manganese bath method

    The manganese bath method is one of the most widespread and exact method to measure neutron source emission rate (neutron source intensity) absolutely at present. Pouring some 56Mn solution with known activity into the bath, the system efficiency can be obtained from γ counts of 56Mn, which is measured by two NaI(Tl) detectors. From saturated counts of a 241Am-Be(α, n) neutron source in the bath, the source emission rate can be obtained. An standard 241Am-Be(α, n) source which is the transfer source of the CCRI(Ⅲ)-K9. AmBe international key comparison organized by the Comite Consultatif des Rayonnements Ionisants, was measured absolutely with the neutron source emission rate standard equipment (manganese bath method). The result is coincident with the average value of the comparison within the uncertainties, therefore the reliability of the standard equipment is verified. (authors)

  3. Participation in IAEA-TEL-201304/28 ALMERA Proficiency Test Exercise on Determination of Anthropogenic Radionuclides in Water and Flour Samples.

    Visetpotjanakit, S; Kaewpaluek, S; Udomsomporn, S

    2016-03-01

    The Office of Atoms for Peace (OAP) participated in the IAEA-TEL-201304/28 ALMERA Proficiency Test Exercise, "Determination of Anthropogenic Radionuclides in Water and Flour Samples," organized by the ALMERA network. There were three test samples sent together with one known activity sample for quality control purpose. Two of the test samples were spiked water: one contained (134)Cs and (137)Cs and the other contained (90)Sr, (60)Co, (152)Eu and (241)Am. The third sample was wheat flour spiked with (134)Cs and (137)Cs. OAP submitted all results to IAEA after determining (134)Cs, (137)Cs, (60)Co, (152)Eu and (241)Am activities by direct gamma-ray counting and (90)Sr by chemical separation and Cerenkov measurement. Our results with critical comments and statistical analysis are described in this paper. PMID:26688353

  4. High resolution alpha particle detectors based on 4H-SiC epitaxial layer

    We fabricated and characterized 4H-SiC Schottky diodes as a spectrometric detector of alpha particles. A thin blocking contact of Ni/Au (15 nm) was used to minimize the influence on alpha particles energy. Current-voltage characteristics of the detector were measured and a low current density below 0.3 nAcm−2 was observed at room temperature. 239Pu241Am244Cm was used as a source of alpha particles within the energy range between 5.1 MeV and 5.8 MeV for detector testing. The charge collection efficiency close to 100 % at reverse bias exceeding 50 V was determined. The best spectrometric performance shows a pulse height spectrum at a reverse bias of 200 V giving an energy resolution of 0.25 % in the full width and half maximum for 5.486 MeV of 241Am

  5. Separation and determination of americium in low-level alkaline waste of NPP origin

    Todorov, B.; Djingova, R.; Nikiforova, A.

    2006-01-01

    The aim of this work is to develop a short and cost-saving procedure for the determination of 241Am in sludge sample of the alkaline low-level radioactive waste (LL LRAW) collected from Nuclear Power Plant “Kozloduy”. The determination of americium was a part of a complex analytical approach, where group actinide separation was achieved. An anion exchange was used for separation of americium from uranium, plutonium and iron. For the separation of americium extraction with diethylhexyl phosphoric acid (DEHPA) was studied. The final radioactive samples were prepared by micro co-precipitation with NdF3, counted by alpha and gamma spectrometry. The procedure takes 2 hours. The recovery yield of the procedure amounts to (95 ± 1.5)% and the detection limit is 53 mBq/kg 241Am (t=150 000 s). The analytical procedure was applied for actual liquid wastes and results were compared to standard procedure.

  6. CdZnTe Frisch collar detectors for γ-ray spectroscopy

    Low-energy γ-ray spectra were collected from 241Am, 57Co, 133Ba, 198Au, 137Cs and 235U using a 3.4x3.4x5.7 mm3 CdZnTe detector utilizing an insulated Frisch ring. The CdZnTe detector was fabricated from a single crystal and a copper shim was used as the Frisch collar. Room-temperature energy resolution of 1.45% full-width half-maximum (FWHM) was obtained for 137Cs at 661.7 keV without electronic correction. The detector fabrication process is described and the resulting energy spectra are discussed. The detector fabrication process is described and the resulting energy spectra are discussed. The detector full-energy-peak intrinsic efficiency is reported for different γ-ray energies, specifically from 241Am, 57Co, 133Ba and 137Cs

  7. Optimization of an analytical method using extraction chromatography for the determination of plutonium, americium and curium in soil samples

    An analytical method for determination of the actinides 238Pu, 239+240Pu, 241Am and 244Cm in soil samples was developed and optimized to allow specific immission measurements of radionuclides in the vicinity of the recently constructed radwaste facility at Wuerenlingen/Switzerland. Following a rapid extraction from the soil sample, as well as a preconcentration step via calcium oxalate precipitation, the actinides are separated using extraction chromatography. Separation of the actinides is carrie out applying the specific resins U/TEVA, TRU and TEVA (Eichrom Technologies IL/USA) and the anion exchange resin BioRAD 1-X2. Measurements are then performed using an α-spectrometer equipped with ion-implanted silicon charged particle detectors. For counting times of less than three days a detection limit of less than 0.05 Bq/kg is obtained for the actinides 238Pu, 239+240Pu, 241Am and 244Cm. (author)

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

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

  9. Gamma-sources on the basis of metallic americium-241

    A batch of gamma-radiation sources has been manufactured from metallic americium-241 of isotopic purity, its activity varying from 0.08 to 0.93 GBq. The cores of the sources are high-purity americium metal condensate on a tantalum or stainless steel substrate prepared by thermal decomposition of 241Pu-241Am alloy in a high vacuum. 7 refs., 1 tab

  10. Development of the in vivo measurement system of bone mineral content using monoenergetic gamma rays

    A system, developed for in vivo measurement of bone mineral content (BMC) using monoenergetic gamma-rays of 241 Am, is described. It presents a discussion of the theoretical and practical aspects of the technique, with details of acquisition and data processing and also discusses the calibration procedure used. The results obtained with in vivo measurements are presented and BMC values of clinically normal subjects and chronic renal patients are compared. (author)

  11. Charged particle detectors made from thin layers of amorphous silicon

    A series of experiments was conducted to determine the feasibility of using hydrogenated amorphous silicon (α-Si:H) as solid state thin film charged particle detectors. 241Am alphas were successfully detected with α-Si:H devices. The measurements and results of these experiments are presented. The problems encountered and changes in the fabrication of the detectors that may improve the performance are discussed

  12. Evaluation of detector positioning for low-energy in vivo gamma spectrometry

    To ensure precision in detector positioning relative to a subject, two dual crystal detectors are mounted on independent assemblies each with six degrees of rotational freedom. All of the possible degrees of movement are furnished with calibrated scale markings for reference purposes. To determine the relative detector positioning variability, a volunteer subject has been repetitively measured over the chest and around the head. In addition, an 241Am lung phantom was measured over the chest in a similar manner

  13. Ascophyllum nodosum (L.) Le Jolis as a bioindicator of radioactivity in the Irish Sea

    Bourne, G S; Assinder, D J

    1991-01-01

    The response of Ascophyllum nodosum to a sudden increase in radioactivity analogous to a nuclear incident is examined in the field. super(137)Cs, super(241)Am and super(239+240)Pu showed net accumulation with exposure time, unlike natural super(228)Th, which was used as a control. Caesium had the highest accumulation rate followed by americium and finally plutonium. Younger plant sections were found to accumulate all the radionuclides significantly faster than older plant sections. Americium ...

  14. A purity monitoring system for liquid argon calorimeters

    For liquid argon calorimeters electronegative impurities dissolved in the medium degrade the detector response and deteriorate the energy resolution, especially at high energies. A concept for a purity monitoring system for liquid argon calorimeters has been developed and is presented here. Special combined monitors of 241Am- and 207Bi-cells are used to monitor the concentration of impurities. The working principle as well as results from test measurements are discussed

  15. Radiometric dating

    The paper on radiometric dating is a chapter in a handbook of Holocene Palaeoecology and Palaeohydrology. This chapter is part of a section on dating methods. Radiocarbon dating is discussed with respect to the apparent ages of lake sediments, seawater, sea creatures and plants. Isotope dating methods for the late Holocene deposits involving 210Pb, 137Cs, sup(239, 240)Pu, 241Am, 32Si and 39Ar are also described. (U.K.)

  16. Methodology for the Inventory and Assessment of Americium Contamination Level in 1987 in an Area of Palomares Contaminated with Plutonium Weapon Grade

    This paper presents a methodology applied for the assessment of the ''241 Am coming from the decay of ''241 Pu isotope content in a contaminated area of Palomares, where the clean-up work done in 1966, given the negligible agricultural importance of such area at the time and its geographical characteristics, was not of the same magnitude as for the rest of the region. (Author) 4 refs

  17. Ionization chamber with fast timing properties and good energy resolution for fission fragment detection

    A twin ionization chamber for fission fragment detection is described. The chamber allows to extract both, fast timing- and energy proportional signals. A time resolution of 1.62 ns FWHM was obtained between two fission fragments detected in the two halves of the chamber. For 241Am α-particles the chamber gave an energy resolution of 1.3 percent. As counting gas methane NTP was used

  18. Neutron field characteristics of Ciemat's Neutron Standards Laboratory Hector Rene Vega-Carrillo

    Guzmán-García, Karen Arlete; Méndez Villafañe, Roberto; Vega-Carrillo, Héctor René

    2015-01-01

    Monte Carlo calculations were carried out to characterize the neutron field produced by the calibration neutron sources of the Neutron Standards Laboratory at the Research Center for Energy, Environment and Technology (CIEMAT) in Spain. For 241AmBe and 252Cf neutron sources, the neutron spectra, the ambient dose equivalent rates and the total neutron fluence rates were estimated. In the calibration hall, there are several items that modify the neutron field. To evaluate their effects differen...

  19. Communication of nuclear data progress: No. 2 (1989)

    This issue includes five parts. The subjects are: (n, r), (n, 2n) measurements; nonstatistical effects in radiative neutron capture; optical model calculation of fission products 92Zr and 138Ba; evaluations of 241Am, 58Fe(n, r) cross section and Ca neutron nuclear data; systematics of (n, np), (n, pn) and (n, d) cross section; and spline fitting for multi-set data with knot optimization

  20. Manche centre. Environment surveillance. Measurement results; Centre de la Manche. La surveillance de l`environnement. Resultats des mesures

    NONE

    1998-11-01

    This booklet reports on the environmental radioactivity measurements performed around the Manche plant (France) during the third quarter of 1998 in rainwater, surface and underground waters, air and grass. Measurements concern the alpha and beta activity, tritium, {sup 137}Cs, {sup 241}Am, {sup 7}Be and {sup 40}K. Other pollutant (metals) measurements on rainwater, rivers surface water and sediments are given. (J.S.)

  1. Studies of Electron Avalanche Behavior in Liquid Argon

    Kim, J.G.; Dardin, S. M.; Jackson, K.H.; Kadel, R. W.(Lawrence Berkeley National Laboratory and University of California, 94720, Berkeley, California, USA); Kadyk, J. A.; Peskov, V.; Wenzel, W. A.

    2002-01-01

    Electron avalanching in liquid argon is being studied as a function of voltage, pressure, radiation intensity, and the concentrations of certain additives, especially xenon. The avalanches produced in an intense electric field at the tip of a tungsten needle are initiated by ionization from a moveable americium (241Am) gamma ray source. Photons from xenon excimers are detected as photomultiplier signals in coincidence with the current pulse from the needle. In pure liquid argon the avalanche ...

  2. Depth dose determination for a mixed radiation field using a thin plastic scintillator dosimetry system

    Aydarous Abdulkadir; Waker Anthony

    2012-01-01

    Plastic scintillators, due to their favorable characteristics compared with other dosimetry techniques, were used as detectors to estimate dose distributions in high gradient dose fields. In this study, a thin plastic scintillator (type BC-408) was coupled to a photomultiplier tube and multichannel analyzer as a technique for real-time dose measurements. The well-defined beta, gamma, and beta-gamma emitters (137Cs, 133Ba, 22Na, 109Cd, 55Fe, and 241Am) have enabled parallel depth dose me...

  3. Effect of physico-chemical properties on metabolism of transuranium oxide aerosols inhaled by beagle dogs

    The oxides of four transuranium isotopes (238Pu, 239Pu, 241Am, and 244Cm), prepared by identical methods of calcining the oxalate at 7500C for two hours, had different physico-chemical properties. For all four oxides the density ranges from 9.8 to 11.4 g cm-3 and initial ultrafilterability (suspended fraction of activity less than 24 A) varied from 0.002 percent for 239PuO2 to 2.24 percent for 238PuO2. Dogs were exposed by nose-only techniques to aerosols generated by nebulizing water suspensions of the oxides. The dogs were sacrificed at intervals from one week to about a year postexposure. The rate of translocation of material from lung to other tissues increased from 239Pu to 238Pu to 241Am to 244Cm, possibly reflecting the decrease in mean particle size from an MMD of 0.7 μm to 239PuO2 to 0.6 μm for 238PuO2 to 0.4 μm for 241AmO2 to 0.1 μm for 244CmO/sub x/. Accumulation of the isotopes in the liver and skeleton as a percentage of final body burden was 1 percent 239Pu and 7 to 23 percent for 238Pu at about a year postexposure, while at 270 days postexposure, values were 40 percent for 241Am and 40 to 30 percent for 244Cm

  4. Evaluation of a novel extraction chromatographic resin material made from room temperature ionic liquid and CMPO for Am uptake

    A novel extraction chromatographic resin material containing CMPO and the room temperature ionic liquid, 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C8-mim+)(NTf2-) was prepared and evaluated for the uptake of 241Am by batch method. The resin showed much higher uptake of Am(III) as compared to the resin made from CMPO in n-dodecane under equivalent loading. (author)

  5. Concentration and speciation of radionuclides in environmental samples

    The paper will describe three examples dealing with the measure of some natural (U, Th, 210Pb, 40K) and artificial (137Cs, 90Sr, 239+240Pu, 241Am) radionuclides in environmental samples such as mosses, sediments, soils. Extraction chromatography, liquid extraction, selective precipitation and electroplating were used to isolate the radionuclides, except for gamma emitters which were detected by gamma spectrometry. Alpha spectrometry were used to measure the alpha emitters and low background beta detector to measure the beta emitters

  6. Energy dispersive x-ray fluorescence (EDXRF) determination of lanthanides after preconcentration on 1-(2-pyridylazo)-2-naphthol modified naphthalene

    A method is described for the simultaneous multielement determination of yttrium and lanthanides at microgram level. This is based on the preconcentration of these lanthanides on to 1-(2-pyridylazo)-2-naphthol modified naphthalene. The quantitation of lanthanides was carried out by energy dispersive X-ray fluorescence analyzer, employing 241Am annular source, via their characteristic K x-rays. The developed procedure gave reliable results in the analysis of xenotime samples. (author) 11 refs.; 2 figs.; 2 tabs

  7. Characterisation of contaminaiton in Maralinga and Emu soils

    A range of Maralinga and Emu soils have been characterised by means of sieving and microparticle classification, yielding mass and activity distribution of plutonium and americium with respect to size. The activity distribution is quite different from the mass distribution and much more variable from sample to sample. While the 241Am activities >0.1 Bq, extends at least 100 km from the firing sites at Taranaki. 19 refs., 17 tabs., 4 figs

  8. Low temperature composite bolometers using RuO2 films as a thermistor

    Results from a massive composite bolometer made of a sapphire crystal and ruthenium oxide films are presented. The properties of such RuO2 films, in the temperature range [50 mK, 200 mK] have been studied. Individual particle detections, using an 241 Am source, have been used to calibrate the system in this temperature interval. Improvements in the performances of such detectors lead to consider them as realistic candidates for the detection of Dark Matter

  9. Radioelement studies in the oceans. Progress report, January 1, 1977--December 31, 1977

    Data are reported on the content of various fallout radionuclides in samples of seawater and sediments collected during 1977 in the Atlantic Ocean, Mediterranean Sea, and Pacific Ocean. Methods used for the preparation of samples for radiometric analysis are described briefly. Radionuclides found included 137Cs, 134Cs, 242Cm, 244Cm, 90Sr, 238Pu, 239Pu, 240Pu, and 241Am. A list is included of publications during the time period covered by this report

  10. Transuranium radionuclides in components of the benthic environment of Enewetak Atoll

    Data on the concentrations and distributions of transuranium radionuclides in the marine environment of Enewetak Atoll are reviewed. The distributions of the transuranics in the lagoon are very heterogeneous. The quantities of transuranics generated during the nuclear-test years at the Atoll and now associated with various sediment components are discussed. Whenever possible, concentrations of 241Am and /sup 239+240/Pu are compared

  11. Evaluation of CZT crystals from the former Soviet Union

    Vertical high pressure Bridgman (VHPB) Cd1-xZnxTe (0.04 241Am radioactive source was found. Electron lifetimes below 1 (micro)s were measured in crystals having significant numbers of micro-defects, compared to lifetimes of 5--15 (micro)s found in spectrometer grade materials produced in the US. Furthermore, the zinc composition along the growth axis showed better homogeneity in comparison with the US material

  12. Screening of natural adsorbents for removal of radio-contaminants from aqueous effluents

    The present paper is a summary of studies carried out to examine the uptake potential of some of the bio/natural adsorbents for removal of radiocontaminants from aqueous effluents. Three different bio/natural materials namely coconut coir pith, sugarcane bagasse and saw dust were selected as adsorbents. Preliminary characterisations of the above adsorbents were carried out and percentage of removal of 239Pu and 241Am from aqueous solutions were checked using batch equilibration method. (author)

  13. Iododeoxyuridine radiosensitization by low- and high-energy photons for brachytherapy dose rates

    The dependence of iododeoxyuridine (IUdR) radiosensitization on photon energy and dose rate in the range of interest to brachytherapy was investigated by irradiating Chinese hamster cells in vitro under aerobic conditions. The radiosensitization produced by 10(-5) and 10(-4) M IUdR for 28-keV (average) photons from 125I, 60-keV photons from 241Am, and 830-keV (average) photons from 226Ra was measured at nominal dose rates of 0.17, 0.30, 0.57, and 0.73 Gy/h. Radiosensitization factors for IUdR were essentially independent of dose rate from 0.30 to 0.73 Gy/h for all cases except for 10(-4) M IUdR plus 241Am, in which case the radiosensitization factor increased from 2.5 +/- 0.2 to 3.0 +/- 0.1. In all cases, the radiosensitization factor decreased significantly as the dose rate was lowered from 0.30 to 0.17 Gy/h e.g., the radiosensitization factor for 241Am dropped to 1.9 +/- 0.2 at a dose rate of 0.17 Gy/h. Moreover, at 0.17 Gy/h the radiosensitization factors were essentially the same for all three photon energies. As the dose rate increased from 0.17 to 0.73 Gy/h, the difference between the radiosensitization factors for the three photon energies became larger; radiosensitization factors for 241Am were higher than those for 226Ra and 125I. In temporary brachytherapy the tumor is irradiated at the higher dose rate of about 0.50-0.70 Gy/h, while the normal tissues are irradiated at lower dose rates; the dose rate dependence of the radiosensitization factor may therefore lead to an improvement in the therapeutic ratio for brachytherapy in combination with IUdR

  14. Study of some health physics parameters of bismuth-ground granulated blast furnace slag shielding concretes

    Kumar, Sandeep; Singh, Sukhpal

    2016-05-01

    The Bismuth-ground granulated blastfurnace slang (Bi-GGBFS) concrete samples were prepared. The weight percentage of different elements present inBi-GGBFS Shielding concretewas evaluated by Energy Dispersive X-ray Microanalysis (EDX). The exposure rate and absorbed dose rate characteristics were calculated theoretically for radioactive sources namely 241Am and 137Cs. Our calculations reveal that the Bi-GGBFS concretes are effective in shielding material for gamma radiations.

  15. Neutron spectra and dosimetric assessment around a neutron Howitzer container

    Barros, Silvia; Gallego Díaz, Eduardo F.; Lorente Fillol, Alfredo; Gonçalves, Isabel F.; Vaz, Pedro; Vega-Carrillo, Héctor René; Zankl, María

    2014-01-01

    The neutron Howitzer container at the Neutron Measurements Laboratory of the Nuclear Engineering Department of the Polytechnic University of Madrid (UPM), is equipped with a 241Am-Be neutron source of 74 GBq in its center. The container allows the source to be in either the irradiation or the storage position. To measure the neutron fluence rate spectra around the Howitzer container, measurements were performed using a Bonner spheres spectrometer and the spectra were unfolded using the NSDann...

  16. Evaluation of neutron data for americium-241

    Maslov, V.M.; Sukhovitskij, E.Sh.; Porodzinskij, Yu.V.; Klepatskij, A.B.; Morogovskij, G.B. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    The evaluation of neutron data for {sup 241}Am is made in the energy region from 10{sup -5} eV up to 20 MeV. The results of the evaluation are compiled in the ENDF/B-VI format. This work is performed under the Project Agreement CIS-03-95 with the International Science and Technology Center (Moscow). The Financing Party for the Project is Japan. The evaluation was requested by Y. Kikuchi (JAERI). (author). 60 refs.

  17. Signal processing in cryogenic particle detection

    Yuryev, Y.N. [Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of); Korea Research Institute of Standards and Science (KRISS), Daejeon (Korea, Republic of); Jang, Y.S. [Korea Research Institute of Standards and Science (KRISS), Daejeon (Korea, Republic of); Kim, S.K. [Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of); Lee, K.B.; Lee, M.K. [Korea Research Institute of Standards and Science (KRISS), Daejeon (Korea, Republic of); Lee, S.J. [Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of); Korea Research Institute of Standards and Science (KRISS), Daejeon (Korea, Republic of); Yoon, W.S. [Korea Research Institute of Standards and Science (KRISS), Daejeon (Korea, Republic of); Kim, Y.H., E-mail: yhkim@kriss.re.k [Korea Research Institute of Standards and Science (KRISS), Daejeon (Korea, Republic of)

    2011-04-11

    We describe a signal-processing program for a data acquisition system for cryogenic particle detectors. The program is based on an optimal-filtering method for high-resolution measurement of calorimetric signals with a significant amount of noise of unknown origin and non-stationary behavior. The program was applied to improve the energy resolution of the alpha particle spectrum of an {sup 241}Am source.

  18. Signal processing in cryogenic particle detection

    Yuryev, Y. N.; Jang, Y. S.; Kim, S. K.; Lee, K. B.; Lee, M. K.; Lee, S. J.; Yoon, W. S.; Kim, Y. H.

    2011-04-01

    We describe a signal-processing program for a data acquisition system for cryogenic particle detectors. The program is based on an optimal-filtering method for high-resolution measurement of calorimetric signals with a significant amount of noise of unknown origin and non-stationary behavior. The program was applied to improve the energy resolution of the alpha particle spectrum of an 241Am source.

  19. Aims and results of the bore-hole development project of the Mecsek Coal Mines (Hungary)

    A project for the joint development of methodology and instrumentation was launched by the Mecsek Coal Mines in order to increase the efficiency of geophysical prospecting. Actual field examples are presented showing the detection of tectonic disturbances by radioactive logging methods from exploratory holes. Results of comparative measurements by means of scintillation and GM-tube detectors using various radiation sources (60Co, 241Am, 90Sr and 137Cs) are given in detail. (Sz.J.)

  20. Measurement of long-lived radionuclides in the Atlantic related to deep-sea disposal of radioactive wastes. Part of a coordinated programme on behaviour of long-lived radionuclides released from deep-ocean dumping activities

    Fish, especially Black Scabbard (Aphanopus carbo), water and sediment were taken from the Northeast Atlantic near a proposed nuclear dumpsite, and analysed for 238Pu, 239+240Pu, 241Am, 137Cs, and 210Po. The concentrations found for black scabbard are lower than those obtained for other deep slope fish and shallow water species. The fish is now known to live in the 800-1400 metre range and hence does not act as a monitor for conditions near the bottom