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Arai, Yoichi; Watanabe, So; Nakahara, Masaumi; Funakoshi, Tomomasa; Hoshino, Takanori; Takahatake, Yoko; Sakamoto, Atsushi; Aihara, Haruka; Hasegawa, Kenta; Yoshida, Toshiki; et al.
Progress in Nuclear Science and Technology (Internet), 7, p.168 - 174, 2025/05
The Japan Atomic Energy Agency (JAEA) has been conducting a project named "Systematic Treatment of RAdioactive liquid waste for Decommissioning (STRAD)" project since 2018 for fundamental and practical studies for treating radioactive liquid wastes with complicated compositions. Fundamental studies have been conducted using genuine liquid wastes accumulated in a hot laboratory of the JAEA called the Chemical Processing Facility (CPF), and treatment procedures for all liquid wastes in CPF were successfully designed on the results obtained. As the next phase of the project, new fundamental and practical studies on primarily organic liquid wastes accumulated in different facilities of JAEA are in progress. This paper reviews the representative achievements of the STRAD project and introduces an overview of ongoing studies.
Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki
Progress in Nuclear Science and Technology (Internet), 7, p.195 - 198, 2025/05
Extraction chromatgraphy technology for trivalent minor actinide (MA(III) ; Am(III) and Cm(III)) recovery from the solution generated by an extraction process in reprocessing of spent nuclear fuel has been developed. A fine particle is generated in the solution. The fine particle must be removed before MA recovery operation, because that leads clogging of the extraction chlomatography column. In order to prevent clogging the column, filtration system utilizing porous silica beads packed column has been designed. In this study, a fine particle trapping system was developed and particle removal performance of the system was experimentally evaluated using alumina particles as simulated fine particle. Column experiments revealed that the fine particle with the particle size from 0.12 to 15 m is cause of clogging of the filtration column. Since simulated fine particles were trapped on filtration experiments, a filtration system using the porous silica beads column is practical,
Minowa, Kazuki*; Watanabe, So; Nakase, Masahiko*; Takahatake, Yoko; Miyazaki, Yasunori; Ban, Yasutoshi; Matsuura, Haruaki*
Nuclear Instruments and Methods in Physics Research B, 556, p.165496_1 - 165496_6, 2024/11
Times Cited Count:0 Percentile:0.00(Instruments & Instrumentation)In this study, X-ray absorption near edge structure (XANES) spectral analysis and column experiments were used to verify the selectivity of rare earth (RE) ions by alkyl diamide amine (ADAAM) adsorbent. In addition, the interactions between the N atoms of ADAAM and RE ions were evaluated to determine whether any of the RE ions are a valid simulant for developing a mutual separation process for minor actinides (MAs) in highly radioactive liquid waste. It was confirmed that La and Ce interacted with the amine N atom of ADAAM and they showed a peak shift of the N-K edge XANES spectrum; this finding suggested that a soft interaction is an essential factor influencing ion selectivity. Therefore, the selection factor of RE ions by ADAAM adsorbent was similar to that of MAs. It was concluded that RE ions are reasonable species to simulate MAs.
Yamamoto, Yuri*; Minowa, Kazuki*; Takahatake, Yoko; Watanabe, So; Nakamura, Masahiro; Matsuura, Haruaki*
Electrochemistry (Internet), 92(4), p.043019_1 - 043019_4, 2024/04
Times Cited Count:0 Percentile:0.00(Electrochemistry)In the pyro-reprocessing of spent nuclear fuel, salt bath is normally used in several times, but at final moment, spent salt containing small amount of chloride nuclear fuel material is generated. In terms of managing nuclear fuel materials, it is desirable that the nuclear fuel materials should be recovered from the spent salt. We are proposing methods for recovering nuclear fuel materials using precipitation by oxide addition and distillation for reducing pressure techniques. In this study, we have focused on the behavior of manganese(II), which is one of the radioactivated products. As a result of experiments and thermodynamic simulation, it was found that manganese(II) is likely to be entrained in nuclear fuel materials. Therefore, it is necessary to add a step to separate manganese(II) from nuclear fuel materials.
Watanabe, So; Takahatake, Yoko; Hasegawa, Kenta; Goto, Ichiro*; Miyazaki, Yasunori; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki
Mechanical Engineering Journal (Internet), 11(2), p.23-00461_1 - 23-00461_10, 2024/04
Iwamoto, Toshihiro; Saito, Madoka*; Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Naruse, Atsuki*; Tsukahara, Takehiko*
Mechanical Engineering Journal (Internet), 11(2), p.23-00444_1 - 23-00444_7, 2024/04
Watanabe, So; Takahatake, Yoko; Ogi, Hiromichi*; Osugi, Takeshi; Taniguchi, Takumi; Sato, Junya; Arai, Tsuyoshi*; Kajinami, Akihiko*
Journal of Nuclear Materials, 585, p.154610_1 - 154610_6, 2023/11
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)Takahatake, Yoko; Watanabe, So; Arai, Tsuyoshi*; Sato, Takahiro*; Shibata, Atsuhiro
Applied Radiation and Isotopes, 196, p.110783_1 - 110783_5, 2023/06
Times Cited Count:2 Percentile:46.61(Chemistry, Inorganic & Nuclear)Watanabe, So; Takahatake, Yoko; Hasegawa, Kenta; Goto, Ichiro*; Miyazaki, Yasunori; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 6 Pages, 2023/05
Iwamoto, Toshihiro; Saito, Madoka*; Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Naruse, Atsuki*; Tsukahara, Takehiko*
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 4 Pages, 2023/05
Applicability of temperature swing extraction technology employing monoamides was examined for uranium contaminated waste treatment procedure. Separation experiments on simulated target solution with three kinds of monoamides with different structure showed that Ce(IV) in the solution was selectively recovered by the temperature swing extraction operation. Based on the experiments, an appropriate monoamide for the procedure was selected.
Takahatake, Yoko; Watanabe, So; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki
Proceedings of 30th International Conference on Nuclear Engineering (ICONE30) (Internet), 4 Pages, 2023/05
High level liquid waste generated from reprocessing of spent nuclear fuel is possible to form precipitations so called as sludge. The sludge will significantly influence on extraction chromatography technology for trivalent minor actinide (MA(III)) recovery. Applicability of a pre-column as a filter for removal of the sludge was experimentally evaluated. In this study, remote handling media exchanging experiments were carried out, and a concept of the pre-column system was proposed based on the results. The media of the pre-column was porous silica particle. Since the media formed block, it interfered water current on ejecting porous silica particle. It was better on trickling basis and using upper outlet than other system, but the operation to control the media block behavior and optimization of water flow is needed.
Nakahara, Masaumi; Watanabe, So; Aihara, Haruka; Takahatake, Yoko; Arai, Yoichi; Ogi, Hiromichi*; Nakamura, Masahiro; Shibata, Atsuhiro; Nomura, Kazunori
Proceedings of International Conference on Nuclear Fuel Cycle; Sustainable Energy Beyond the Pandemic (GLOBAL 2022) (Internet), 4 Pages, 2022/07
Various radioactive wastes have been generated from Chemical Processing Facility for basic research on advanced reactor fuel reprocessing, radioactive waste disposal, and nuclear fuel cycle technology. Many types of reagents have been used for the experiments, and some troublesome materials were produced in the course of experiments. The radioactive liquid wastes were treated for stable and safe storage using decomposition, solvent extraction, precipitation, and solidification methods. In this study, current status of harmless treatment for the radioactive liquid wastes would be reported.
Takahatake, Yoko; Watanabe, So; Irisawa, Keita; Shiwaku, Hideaki; Watanabe, Masayuki
Journal of Nuclear Materials, 556, p.153170_1 - 153170_7, 2021/12
Times Cited Count:5 Percentile:49.08(Materials Science, Multidisciplinary)Sugiyama, Daisuke*; Nakabayashi, Ryo*; Tanaka, Shingo*; Koma, Yoshikazu; Takahatake, Yoko
Journal of Nuclear Science and Technology, 58(4), p.493 - 506, 2021/04
Times Cited Count:2 Percentile:20.79(Nuclear Science & Technology)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:77.98(Nuclear Science & Technology)Sugiyama, Daisuke*; Nakabayashi, Ryo*; Koma, Yoshikazu; Takahatake, Yoko; Tsukamoto, Masaki*
Journal of Nuclear Science and Technology, 56(9-10), p.881 - 890, 2019/09
Times Cited Count:4 Percentile:34.09(Nuclear Science & Technology)Takahatake, Yoko; Koma, Yoshikazu
Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 4 Pages, 2019/05
Takahatake, Yoko; Ambai, Hiromu; Sano, Yuichi; Takeuchi, Masayuki; Koizumi, Kenji; Sakamoto, Kan*; Yamashita, Shinichiro
Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 9 Pages, 2018/10
The corrosion behaviour of FeCrAl-ODS steels for the accident tolerant fuel cladding of LWRs were investigated in nitric acid solutions for the reprocessing process of spent fuels. The corrosion tests were carried out at 60C, 80
C and the boiling point of the solutions, and the specimens were then analysed by XPS. The corrosion remarkably progressed at the boiling point, and the highest corrosion rate was 0.22 mm/y. In the oxide film, the atomic concentration of Fe was lower, than that in the base material, and those of Cr and Al were higher. The results show that the corrosion of FeCrAl-ODS steels in hot nitric acid solution is not severe because of the high corrosion resistance of the oxide film formed on the material; hence, the corrosion resistance of the new cladding materials in the dissolution process of spent fuel is acceptable for reprocessing operations.
Sano, Yuichi; Ambai, Hiromu; Takahatake, Yoko
Aichi Shinkurotoron Hikari Senta 2017-Nendo Kokyoto Riyo Seika Hokokusho (Internet), 1 Pages, 2018/00
In order to elucidate the mechanism of corrosion in the reprocessing process and propose a method for suppressing corrosion, the effect of coexisting substances on the chemical form of Ru in nitric acid solution containing seawater components was evaluated. The result of XAFS measurement for Ru showed the structural change around a Ru atom due to the interaction with chloride ion, which will suppress the corrosion promoting action of Ru in nitric acid solution.
Takahatake, Yoko; Shibata, Atsuhiro; Nomura, Kazunori; Sato, Tsutomu*
Minerals (Internet), 7(12), p.247_1 - 247_13, 2017/12
Times Cited Count:9 Percentile:42.19(Geochemistry & Geophysics)Hydrous sodium titanate (SrTreat) is able to remove radioactive Sr from Radioactive contaminated water at Fukushima Daiichi Nuclear Power station (F1NPS). Knowing the amount of radioactive nuclides in the used SrTreat is important for an effective disposal and deposition of the F1NPS waste. This study investigated changes in the ability of SrTreat to sorb Sr during its use, and to understand the causes of changes in the sorbing. After exposure to a simulated treated water for 99 h, the surface structure of the SrTreat was changed, and the percentage of sorbed Sr and the buffer capacity for protons decreased. When the amount of radioactive nuclides contained in the used SrTreat is calculated from the sorption data of the as received SrTreat.