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Watanabe, So; Ogi, Hiromichi*; Arai, Yoichi; Aihara, Haruka; Takahatake, Yoko; Shibata, Atsuhiro; Nomura, Kazunori; Kamiya, Yuichi*; Asanuma, Noriko*; Matsuura, Haruaki*; et al.
Progress in Nuclear Energy, 117, p.103090_1 - 103090_8, 2019/11
Times Cited Count：14 Percentile：79.50(Nuclear Science & Technology)Ohashi, Yusuke; Harada, Masayuki*; Asanuma, Noriko*; Ando, Shion; Tanaka, Yoshio; Ikeda, Yasuhisa*
Journal of Radioanalytical and Nuclear Chemistry, 311(1), p.491 - 502, 2017/01
Times Cited Count：1 Percentile：9.62(Chemistry, Analytical)In order to assess the feasibility of method for recovering U from wastes containing uranium (scrap uranium) using polyvinylpolypyrrolidone (PVPP) adsorbent, we have examined the adsorption and desorption behavior of metal species in HCl aqueous solutions dissolving scrap uranium. It was found that the U(VI) species are selectively adsorbed onto PVPP regardless of the presence of a large amount of Na(I) and Al(III), that the adsorbed U(VI) species are desorbed from PVPP column selectively by water. Pure uranium was efficiently recovered from the eluates. From these results, the PVPP resin is expected to be used as the adsorbent in the treatment process of scrap uranium.
Ohashi, Yusuke; Asanuma, Noriko*; Harada, Masayuki*; Tanaka, Yoshio; Ikeda, Yasuhisa*
Journal of Radioanalytical and Nuclear Chemistry, 309(2), p.627 - 636, 2016/08
Times Cited Count：8 Percentile：56.75(Chemistry, Analytical)As one of methods for recovering uranium from the uranium-bearing wastes, we have proposed the electrolytic deposition method using choline chloride-urea (CCU) which is known as an ambient temperature molten salt. More than 92% of uranium components in inactivated alumina and spent sodium fluoride adsorbent was dissolved into CCU solution. Cyclic voltammograms (CVs) of the solutions prepared by dissolving uranium-bearing wastes in CCU were measured in the potential range of -2.0 to 1.1 V (vs. Ag/AgCl). The one reduction peak was observed around -0.7 V for all solutions. Based on the results of CVs, bulk electrolyses of the solutions dissolving uranium-bearing wastes were also carried out at -1.5V at 80 
C. The deposits were formed on a carbon electrode as cathode. Consequently, we confirmed that CCU is effective media for recovering uranium selectively from uranium-bearing waste.
Ohashi, Yusuke; Harada, Masayuki*; Asanuma, Noriko*; Ikeda, Yasuhisa*
Journal of Nuclear Materials, 464, p.119 - 127, 2015/09
Times Cited Count：18 Percentile：80.16(Materials Science, Multidisciplinary)In order to examine feasibility of the electrochemical deposition method for recovering uranium from the solid wastes contaminated with uranium using ionic liquid as electrolyte, we have studied the electrochemical behavior of each solution prepared by soaking the spent NaF adsorbents and the steel waste contaminated with uranium in BMICl (1-butyl-3-methyl- imidazolium chloride). The uranyl(VI) species in BMICl solutions were found to be reduced to U(V) irreversibly around -0.8 to -1.3 V vs. Ag/AgCl. Based on the electrochemical data, we have performed potential controlled electrolysis of each solution at -1.5 V vs. Ag/AgCl. Black deposit was obtained, and their composition analyses suggest that the deposit is the mixtures of U(IV) and U(VI) compounds containing O, F, Cl, and N elements. From the present study, it is expected that the solid wastes contaminated with uranium can be decontaminated by treating them in BMICl and the dissolved uranium species are recovered electrolytically.
Ohashi, Yusuke; Asanuma, Noriko*; Harada, Masayuki*; Wada, Yukio*; Matsubara, Tatsuo; Ikeda, Yasuhisa*
Journal of Nuclear Science and Technology, 46(8), p.771 - 775, 2009/08
Most of the metal or bed material wastes generated from uranium enrichment facilities or uranium refining and conversion plants are contaminated by uranium fluoride compounds such as UF. The UF powder was completely dissolved in BMICl(1-buthyl-3-methylimidazolium chloride). The uranium concentrations of metal waste dropped below the temporary proposed clearance level (1.0 Bq/g) using BMICl. In the cyclic voltammogram of BMICl solution when dissolving UF, uncoupled reduction and oxidation peaks were observed and the reduction peak was considered to correspond to the reduction of uranyl(VI) + e
uranyl(V) followed by further reduction to UO
.
Morita, Yasuji; Kawata, Yoshihisa*; Mineo, Hideaki; Koshino, Nobuyoshi*; Asanuma, Noriko*; Ikeda, Yasuhisa*; Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*
Journal of Nuclear Science and Technology, 44(3), p.354 - 360, 2007/03
Times Cited Count：16 Percentile：71.14(Nuclear Science & Technology)Precipitation behavior of Pu and other transuranium elements with N-cyclohexyl-2-pyrrolidone (NCP) has been examined to develop a simple reprocessing based only on precipitation method. From HNO
solutions containing only Pu, both Pu(VI) and Pu(IV) were precipitated with NCP, but they required more NCP than in the U(VI) precipitation. Selective U(VI) precipitation from HNO solution containing U(VI) and Pu(IV) was achieved by stirring the solution for sufficient time after addition of NCP with ratio of [NCP]/[U]=1.4. Addition of an enough amount of NCP to U(VI)-Pu(VI) or U(VI)-Pu(IV) solutions gave a quantitative precipitation of both U and Pu. Neither Am(III) nor Np(V) was precipitated in the selective U precipitation and the simultaneous U-Pu precipitation. These results demonstrate the feasibility of the reprocessing by precipitation with NCP.
Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*; Morita, Yasuji; Kawata, Yoshihisa*; Mineo, Hideaki; Koshino, Nobuyoshi*; Asanuma, Noriko*; Harada, Masayuki*; et al.
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 4 Pages, 2005/10
N-cyclohexyl-2-pyrrolidone (NCP), can selectively precipitate U(VI) ions in aqueous nitric acid solutions. Utilizing this property, we have been developing a simple reprocessing process of spent nuclear fuel based only on precipitation method. In the first precipitation step, only U is separated by precipitation in a yield of about 70%, and in the second precipitation step both U and Pu are recovered and separated from fission products (FP) and other transuranium elements (TRU). In the present study, a precipitator and a precipitate separator were designed and built up, and were tested with aspets of operationability and system performance.
Morita, Yasuji; Kawata, Yoshihisa*; Mineo, Hideaki; Koshino, Nobuyoshi*; Asanuma, Noriko*; Ikeda, Yasuhisa*; Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
N-cyclohexyl-2-pyrrolidone (NCP) can selectively precipitate U(VI) ions in aqueous nitric acid solutions. Utilizing this property, we have been developing a simple reprocessing process of spent nuclear fuel based only on precipitation method. In the first precipitation step, only U is separated by precipitation in a yield of about 70%, and in the second precipitation step both U and Pu are recovered and separated from fission products (FP) and other transuranium elements (TRU). In JAERI, precipitation behaviors of Pu and other TRU were examined experimentally, and the results showed the feasibility of the process establishement.
Hayashi, Takumi; Kobayashi, Kazuhiro; Iwai, Yasunori; Asanuma, Noriko; Ohira, Shigeru; Nishi, Masataka
Fusion Science and Technology, 41(3), p.647 - 651, 2002/05
no abstracts in English
Kobayashi, Kazuhiro; Hayashi, Takumi; Iwai, Yasunori; Asanuma, Noriko; Nishi, Masataka
Fusion Science and Technology, 41(3), p.673 - 677, 2002/05
no abstracts in English
Ohashi, Yusuke; Asanuma, Noriko*; Harada, Masayuki*; Ikeda, Yasuhisa*
no journal, ,
In the cyclic voltammogram of BMICl solution when dissolving metal waste contaminated with UF, uncoupled reduction peak and a pair of oxidation-reduction peaks were observed around -1.0V and 0V. The reduction peak was considered to correspond to the reduction of U(VI) U(V). A pair of peaks were considered to be the reversible peak of Fe(III) Fe(II). After the electrolysis of the solution, the working electrode was washed by ethanol. From the results of XPS measurement, uranium component was observed on the surface of the electrode though no Fe conponent was observed. Hence we would expect that the uranium component could be recovered by electrolysis from the solution generated in the decontamination treatment of the steel wastes contaminated with UF in BMICl.
Ohashi, Yusuke; Harada, Masayuki*; Asanuma, Noriko*; Ikeda, Yasuhisa*
no journal, ,
Solid and liquid radioactive waste derived from research and development for uranium refining and conversion has been stored at the Japan Atomic Energy Agency Ningyo-toge Environmental Engineering Center. The solid waste with uranium totals 1500ton.Most of this waste is considered to exceed the radioactivity level for VLLW. Hence we have proposed to recover uranium using adsorbent with high selectivity to uranium after dissolving sludge into inorganic acid. Dissolution experiments were carried out by adding each sludge sample into 1N hydrochloric acid as changing dissolution time. 90% of Uranium in calcium fluoride sludge dissolved within 10 minutes. Calcium fluoride itself didn't dissolved completely. Main component of active alumina adsorbent dissolved slowly though uranium in active alumina adsorbent dissolved completely within 10 minutes. Main component of sodium fluoride adsorbent and uranium in it dissolved completely within 10 minutes.
Ohashi, Yusuke; Ando, Shion; Tsunashima, Yasumichi; Harada, Masayuki*; Ikeda, Yasuhisa*; Asanuma, Noriko*
no journal, ,
Sludge like uranium bearing waste and adsorbent were dissolved using hydrochloric acid. Uranium in the solution is recovered using PVPP. Recovered uranium was desorbed from PVPP using pure water and then uranium was recovered as uranium peroxide. As a result, it was confirmed that highly pure uranium was recovered.
Ibe, Junya*; Mitani, Mao*; Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Asanuma, Noriko*; Matsuura, Haruaki*
no journal, ,
Asanuma, Noriko*; Miyano, Riku*; Shimizu, Tomu*; Aihara, Haruka; Watanabe, So; Nomura, Kazunori
no journal, ,
no abstracts in English
Watanabe, So; Ogi, Hiromichi*; Arai, Yoichi; Aihara, Haruka; Shibata, Atsuhiro; Nomura, Kazunori; Kamiya, Yuichi*; Asanuma, Noriko*; Matsuura, Haruaki*; Kubota, Toshio*; et al.
no journal, ,
Ibe, Junya*; Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Asanuma, Noriko*; Matsuura, Haruaki*
no journal, ,
Since waste salt generated from pyro-reprocessing test which contains uranium can easily capture moisture from the air and corrode equipment and piping material, further treatment technology for decontamination and waste stabilization is required. The aim of this study is to develop a simple separation method for decontamination of salts. First, LiCl-KCl eutectic and NaCl-2CsCl salts were used as melt baths, lithium oxide was used as a precipitant, and cerium chloride was used as uranium surrogate for testing the precipitation process in glove box. Next, since the actual waste salt is precipitated outside the glovebox. From the results obtained by structural analysis and XRD on precipitates generated, it is considered that oxychloride was formed by the similarity in EXAFS oscillation and X-ray diffraction patterns.
Takahatake, Yoko; Sakamoto, Atsushi; Asanuma, Noriko*; Matsuura, Haruaki*; Watanabe, So; Watanabe, Masayuki
no journal, ,
no abstracts in English
Aso, Hiroki*; Toyosaki, Ayaka*; Asanuma, Noriko*; Takahatake, Yoko; Hoshino, Takanori; Watanabe, So; Watanabe, Masayuki; Matsuura, Haruaki*
no journal, ,
no abstracts in English
Suzuki, Tatsuya*; Honda, Masanori*; Asanuma, Noriko*; Osaka, Masahiko
no journal, ,
Pyridine-resin based ion-exchange method has been proposed as a recovery technique of molybdenum from high level waste. A batch experiment was carried out for the evaluation of Mo distribution coefficient to the pyridine-resin. Zirconium adsorption behavior was also investigated.
