Miyamoto, Yutaka; Yasuda, Kenichiro
Journal of Nuclear and Radiochemical Sciences (Internet), 18, p.13 - 15, 2018/07
A sequential separation technique using an anion-exchange column developed in the previous works have the potential to completely separate picograms of Am from the lanthanides using mixtures of acetic acid, hydrochloric acid, and nitric acid as the eluents, without any functional ligands or special columns. This experimental result implies that ultra-trace actinides, including Am, Pu, U, and Th in environmental samples can be sequentially separated by combination of these mixed-media eluents and an anion exchange column.
Kaneko, Masashi; Watanabe, Masayuki; Miyashita, Sunao*; Nakashima, Satoru*
Journal of Nuclear and Radiochemical Sciences (Internet), 17, p.9 - 15, 2017/03
Density functional calculations were applied to the complexation of Eu(III) and Am(III) ions with phosphinic acid (O-donor) and dihiophosphinic acid (S-donor) from the viewpoint of the bonding nature of valence orbitals in metal ion. Two and four conformers for S-donor and O-donor complexes, respectively were optimized. Their stabilization energies by complex formation toward [M(HO)] were estimated. As the result, the energies reproduced the experimental Am(III)/Eu(III) selectivity that O-donor ligand preferably coordinates to Eu(III) ion, whereas S-donor ligand selectively coordinates to Am(III) ion. Focused on the bonding natures of d and f-orbital electrons, it was indicated that the d-orbital electrons in both Eu and Am complexes participate in the covalency as bonding-type nature and have the almost same contribution. Meanwhile, the contribution of the f-orbital electrons was different between Eu and Am complexes and indicated that in the case of S-donor complex, non-bonding type and bonding type contributions were observed for Eu and Am complexes, respectively and in the case of O-donor complex, bonding type and anti-bonding type contributions were observed for Eu and Am complexes, respectively. This result suggested that the bonding natures of d-orbital electrons contribute to the geometrical similarity of molecular structures for Eu and Am complexes and the bonding natures of f-orbital electrons contribute to the difference in the selectivity of Eu and Am ions.
Kasamatsu, Yoshitaka*; Toyoshima, Atsushi; Tome, Hayato*; Tsukada, Kazuaki; Asai, Masato; Haba, Hiromitsu*; Nagame, Yuichiro
Journal of Nuclear and Radiochemical Sciences (Internet), 13(1), p.9 - 12, 2013/06
Adsorption behavior of the group-5 elements, Nb and Ta, on cation-exchange resin was studied in mixed solution of HF and HNO as a model experiment of their heavier homologue, element 105 (dubnium, Db). Chemical reactions of these elements in the cation exchange rapidly reached the equilibrium. It was found that distribution coefficients of Nb and Ta decrease with increasing the fluoride ion concentration in the studied range of 10 - 10 M. Clear difference between Nb and Ta was observed in the variations of the distribution coefficients against the fluoride ion concentration. This would originate from their different chemical species of fluoride complexes. We propose the cation-exchange experiment of Db based on the present experimental results to understand its fluoride complex formation.
Asai, Masato; Kaneya, Yusuke*; Sato, Tetsuya; Tsukada, Kazuaki; Oe, Kazuhiro; Sato, Nozomi; Toyoshima, Atsushi
Journal of Nuclear and Radiochemical Sciences (Internet), 12(1), p.5 - 10, 2012/06
To measure radioactivities in soil contaminated by the accident of the Fukushima Daiichi Nuclear Power Plant, efficiency calibration of Ge detectors for I, Cs, and Cs in volume sources was investigated. -ray detection efficiencies for these nuclei were determined precisely using standard soil samples containing Cs, Cs, Hf, and Zr. These standard sources were prepared by admixing radioactive solutions with soil, and point sources were made from the same solutions to determine their radioactivity concentrations. Cascade summing corrections for rays of Cs in soil samples were evaluated experimentally. To easily calculate the cascade summing corrections for volume sources, we examined a simplified method using averaged efficiencies, and evaluated its validity through a comparison of the calculated correction factors with the experimental ones.
Journal of Nuclear and Radiochemical Sciences, 12(1), p.A1 - A6, 2012/05
Chemical studies of rutherfordium (Rf) and nobelium (No) recently carried out at JAEA are reviewed. Anion-exchange behavior of Rf in HF and HNO mixed solution was studied together with short-lived Zr and Hf isotopes using an automated chemistry apparatus. It was found that the hexafluoro complex of Rf is present in the solutions under the given conditions where the same complexes of Zr and Hf are existing. The formation constant of the Rf complex was evaluated to be at least one order of magnitude smaller than those of Zr and Hf. Oxidation experiments of No was conducted in 0.1 M -hydroxyisobutyric (-HIB) acid using a newly developed electrolytic column chromatography apparatus on an atom-at-a-time scale. The result clearly demonstrated that stable No is successfully oxidized to the trivalent state, No, which is held in the -HIB solution.
Usuda, Shigekazu*; Magara, Masaaki; Esaka, Fumitaka; Yasuda, Kenichiro; Kokubu, Yoko; Lee, C. G.; Miyamoto, Yutaka; Suzuki, Daisuke; Inagawa, Jun; Sakurai, Satoshi; et al.
Journal of Nuclear and Radiochemical Sciences, 11(2), p.A5 - A9, 2011/01
In the analysis of IAEA safeguards environmental samples, isotope ratios of ultra-trace amounts of uranium and plutonium in samples taken from nuclear facilities are determined to detect undeclared nuclear materials and activities. In order to keep and enhance the reliability of the measurement results, validation of analytical methods and estimation of measurement uncertainty in such ultra-trace analysis should be properly done in accordance with worldwide standards. In this paper, the current activities on achievement of QA/QC (quality assurance and quality control) and estimation of measurement uncertainty in the ultra-trace analysis at a clean chemistry laboratory (CLEAR) of JAEA are reported.
Toyoshima, Atsushi; Kasamatsu, Yoshitaka*; Tsukada, Kazuaki; Asai, Masato; Ishii, Yasuo; Tome, Hayato*; Nishinaka, Ichiro; Sato, Tetsuya; Nagame, Yuichiro; Schdel, M.; et al.
Journal of Nuclear and Radiochemical Sciences, 11(1), p.7 - 11, 2010/06
The extraction behavior of rutherfordium (Rf) into trioctylphosphine oxide (TOPO) from 2.0 - 7.0 M HCl solution was studied together with that of the homologues Zr and Hf. The extracted yields of Rf, Zr, and Hf increased with an increase of HCl concentration, and the sequence of their extraction was Zr Hf Rf. It is suggested that the stability of the RfCl2(TOPO) complex is lower than that of the corresponding species of the homologues.
Miyamoto, Yutaka; Yasuda, Kenichiro; Magara, Masaaki; Kimura, Takaumi; Usuda, Shigekazu*
Journal of Nuclear and Radiochemical Sciences, 10(2), p.7 - 12, 2009/12
With combination of a single anion-exchange column and mixed-media of CHCOOH and other acids (HCl and/or HNO), 50 ng of U, Th, Pb, and lanthanides were sequentially separated. All of the elements were recovered more than 95%, and the decontamination factor was more than 100. This separation technique reduces separation time and simplified the complicated traditional processes without any special reagents and equipments.
Kasamatsu, Yoshitaka; Toyoshima, Atsushi; Tome, Hayato; Tsukada, Kazuaki; Haba, Hiromitsu*; Nagame, Yuichiro
Journal of Nuclear and Radiochemical Sciences, 8(2), p.69 - 72, 2007/10
We investigated anion-exchange behavior of Nb, Ta and Pa in HF/HNO media to find suitable experimental conditions for the study of the Db fluoride complex formation. We measured Kd values of Nb, Ta and Pa on strong basic anion exchangers in the wide range of the fluoride ion concentration, 110210M, in order to in detail investigate anionic fluoride complex formation of those elements. We have used tracer concentrations of isotopes of Nb, Ta and Pa in the experiments. Variation of the Kd values as a function of [NO] was also studied. As a result, we observed an apparent difference in the adsorption behavior of the homologues. Based on these results together with the measurement of the equilibrium time, we propose rapid online experimental condition for the study of Db fluoride.
Watanabe, Satoshi; Katabuchi, Tatsuya*; Ishioka, Noriko; Matsuhashi, Shimpei
Journal of Nuclear and Radiochemical Sciences, 8(2), p.105 - 107, 2007/10
Sakamoto, Fuminori; Nankawa, Takuya; Kozai, Naofumi; Fujii, Tsutomu*; Iefuji, Haruyuki*; Francis, A. J.; Onuki, Toshihiko
Journal of Nuclear and Radiochemical Sciences, 8(2), p.133 - 136, 2007/10
Protein expression of grown in the medium containing U(VI) and U(VI) was examined by two-dimensional gel electrophoresis. of BY4743 was grown in medium containing U of 0, 2.0, and 5.0 10 M or U of 2.5 10 (radioactivity was higher by 350 times than 2.0 10 M U) and 5.0 10 M for 112 h at 30C. The growths of the yeast grown in the above media were in the following order: control 2.5 10 M U 2.0 10 M U 5.0 10 M U 5.0 10 M U. This result indicated that not only radiological but also chemical effect of U reduced the growth of the yeast. The concentrations of U in the medium containing U or U decreased, suggesting U accumulation by the yeast cells. The 2-D gel electrophoresis analysis showed the appearance of several spots after exposure to U or to U but not in the control containing no uranium. These results show that the yeast cells exposed to U express several specific proteins.
Francis, A. J.; Dodge, C. J.*; Onuki, Toshihiko
Journal of Nuclear and Radiochemical Sciences, 8(2), p.121 - 126, 2007/10
We investigated the biotransformation of Pu(IV)-citrate by under aerobic conditions. Citric acid was rapidly metabolized by resulting in the formation of Pu polymer. Addition of Pu(VI) to a mixture consisting of bacterial cells and kaolinite clay showed that the Pu was preferentially associated with bacterial cells as Pu(IV) and that Pu(VI) was reduced to Pu(V) and Pu(IV) only in the presence of bacteria.
Nishio, Katsuhisa; Hofmann, S.*; Ikezoe, Hiroshi; Heberger, F. P.*; Ackermann, D.*; Antalic, S.*; Comas, V. F.*; Gan, Z.*; Heinz, S.*; Heredia, J. A.*; et al.
Journal of Nuclear and Radiochemical Sciences, 8(2), p.73 - 78, 2007/10
Journal of Nuclear and Radiochemical Sciences, 6(8), p.205 - 210, 2005/12
no abstracts in English
Matsuoka, Hiromitsu; Hashimoto, Kazuyuki; Hishinuma, Yukio*; Ishikawa, Koji*; Terunuma, Hitoshi*; Tatenuma, Katsuyoshi*; Uchida, Shoji*
Journal of Nuclear and Radiochemical Sciences, 6(3), p.189 - 191, 2005/12
Applicability of Mo adsorbent PZC(Poly Zirconium Compound) for W/Re generator was investigated. Long term stability of adsorption of W to the PZC column, elution of Re from PZC column, desorption of from PZC column, and labeling of Hydroxyethylidene Diphosphonic Acid(HEDP) and Mercaptoacetyltriglycine(MAG3) with Re eluted from PZC column were tested. The PZC generator gave reproducible Re elution yields with low W parent breakthrough for a long period of time(about 5 months), that is the W/Re generator using PZC has a potential for practical use.
Hashimoto, Kazuyuki; Wan, K. W. H. B. B.*; Matsuoka, Hiromitsu
Journal of Nuclear and Radiochemical Sciences, 6(3), p.193 - 196, 2005/12
The radioisotopes of rhenium (Re and Re) are attractive radionuclides for radiotherapy because of their energetic beta particles and gamma rays suitable for imaging. Mercaptoacetyltriglycine, MAG3 (NS ligand), is a useful bifunctional ligand in labeling monoclonal antibodies with metallic radionuclides. In this study, the labeling of MAG3 with carrier-free Re from a W/Re generator was investigated in detail. The Re-MAG3 complex was synthesized by the direct labeling method and by the indirect labeling method using a transfer ligand (citric acid or gluconic acid). The dependence of the labeling yield upon the reaction conditions such as the concentrations of tin(II) chloride dihydrate as a reducing agent, S-benzoyl MAG3 and the transfer ligand, pH, temperature, reaction time and the addition of a carrier was examined. The labeling yield of Re-MAG3 synthesized by the all method was over 90% under the optimum conditions.
Asakura, Toshihide; Kim, S.-Y.; Morita, Yasuji; Ozawa, Masaki*
Journal of Nuclear and Radiochemical Sciences, 6(3), p.267 - 269, 2005/12
An electrolytic extraction (EE) method, i.e. electro-reductive deposition, of Tc from nitric acid aqueous solution was studied for future reprocessing. After 30 min of constant potential electrolysis by carbon electrode at -0.3 V vs. SSE (Standard Silver Electrode), Tc concentration in 3 M nitric acid decreased to 93 % of the initial value, which corresponds to 7 % of deposition. With co-existence of Pd, the value reached to 15 % of deposition equivalent by electrolysis at 0.0 V vs. SSE for 60 min. An acceleration effect of Pd on Tc deposition (promoter effect) was suggested. The concentration, however, increased to the initial value after further electrolysis and competing re-dissolution of deposited Tc was also suggested. In cyclic voltammetry measurements, it was found that the deposit from Tc-Pd-Ru-Rh solution dissolved easier than that from Pd-Ru-Rh did. In electrolyzed Tc solution, an absorption peak at 482 nm was found. It can be attributed to the complex with nitrite anion, and the complex formation is proposed as one possible mechanism of Tc re-dissolution.
Asakura, Toshihide; Hotoku, Shinobu; Ban, Yasutoshi; Matsumura, Masakazu; Morita, Yasuji
Journal of Nuclear and Radiochemical Sciences, 6(3), p.271 - 274, 2005/12
Tc extraction and separation experiments were performed basing on PUREX technique with using spent UO fuel with burn-up of 44 GWd/t. The experimental results were examined with performing calculations by a simulation code ESSCAR (Extraction System Simulation Code for Advanced Reprocessing). It was demonstrated that Tc can be almost quantitatively extracted from a dissolver solution and that Tc can also be almost quantitatively recovered by scrubbing. Further, it was clearly presented from the calculation results of ESSCAR that the extraction mechanism of Tc is dominated by the synergistic effect of Zr and U.
Journal of Nuclear and Radiochemical Sciences, 6(2), p.A21 - A28, 2005/12
no abstracts in English
Aoyama, Takafumi; Maeda, Shigetaka; Maeda, Yukimoto; Suzuki, Soju
Journal of Nuclear and Radiochemical Sciences, 6(3), p.279 - 282, 2005/12
The present study examines the potential for the demonstration of fission product transmutation in the experimental fast reactor JOYO at JNC's Oarai Engineering Center. The possibility of creating a highly-efficient transmutation irradiation field by loading neutron moderating subassemblies in the reflector region of JOYO was examined in a series of scoping calculations. A cluster of reflector subassemblies was replaced with beryllium or zirconium hydride (ZrH1.65) moderated subassemblies. These moderated subassemblies surrounded one central test subassembly that would contain Tc or I target material. The Tc transmutation rate was 16.2% using ZrH and 13.9% using beryllium as moderator. As a result of this study, basic characteristics of LLFP transmutation in JOYO using relevant moderator materials were investigated and the future feasibility was shown.