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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,
Nozaki, Yukio*; Sukegawa, Hiroaki*; Watanabe, Shinichi*; Yunoki, Seiji*; Horaguchi, Taisuke*; Nakayama, Hayato*; Yamanoi, Kazuto*; Wen, Z.*; He, C.*; Song, J.*; et al.
Science and Technology of Advanced Materials, 26(1), p.2428153_1 - 2428153_39, 2025/02
Times Cited Count:0 Percentile:0.00(Materials Science, Multidisciplinary)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.
Oguri, Kaori; Hagura, Naoto*; Yamaguchi, Akiko; Okumura, Masahiko; Matsuura, Haruaki*; Tsunashima, Yasumichi; Aoki, Katsumi; Arai, Yoichi; Watanabe, So
Nuclear Instruments and Methods in Physics Research B, 556, p.165516_1 - 165516_8, 2024/11
Times Cited Count:0 Percentile:0.00(Instruments & Instrumentation)Ningyo-toge is the uranium mine that has been operated in Japan. Various radioactive elements such as Uranium (U), and Radium (Ra) are still present in the mine ground water with very small amount, and behavior of those elements is not fully understood. In this study, we investigated the composition of metal oxides and clay minerals in a soil of slag deposit at the mine, and systematics of adsorption structure of various ions were examined. Identifying the composition and chemical forms of minerals present in the soil of slag can provide useful information for the safety assessment and evaluation of influence on the surrounding environment.
Watanabe, Kenichi*; Sugai, Yusuke*; Hasegawa, Sota*; Tanaka, Seishiro*; Hitomi, Keitaro*; Nogami, Mitsuhiro*; Shinohara, Takenao; Su, Y. H.; Parker, J. D.*; Kockelmann, W.*
Scientific Reports (Internet), 14, p.25224_1 - 25224_13, 2024/10
Times Cited Count:0 Percentile:0.00(Multidisciplinary Sciences)Sato, Nobuaki*; Kameo, Yutaka; Sato, Soichi; Kumagai, Yuta; Sato, Tomonori; Yamamoto, Masahiro*; Watanabe, Yutaka*; Nagai, Takayuki; Niibori, Yuichi*; Watanabe, Masayuki; et al.
Introduction to Dismantling and Decommissioning Chemistry, 251 Pages, 2024/09
This book focuses on the dismantling and decommissioning of nuclear facilities and reactors that have suffered severe accidents. In Part 1, we introduce basic aspects ranging from fuel chemistry, analytical chemistry, radiation chemistry, corrosion, and decontamination chemistry to waste treatment and disposal. Then, Part 2 covers the chemistry involved in the decommissioning of various nuclear facilities, and discusses what chemical approaches are necessary and possible for the decommissioning of TEPCO's Fukushima Daiichi Nuclear Power Plants, how decommissioning should be carried out, and what kind of research and development and also human resource development are required for this.
Arai, Yoichi; Watanabe, So; Watanabe, Masayuki; Arai, Tsuyoshi*; Katsuki, Kenta*; Agou, Tomohiro*; Fujikawa, Hisaharu*; Takeda, Keisuke*; Fukumoto, Hiroki*; Hoshina, Hiroyuki*; et al.
Nuclear Instruments and Methods in Physics Research B, 554, p.165448_1 - 165448_10, 2024/09
Times Cited Count:0 Percentile:0.00(Instruments & Instrumentation)Nakahara, Masaumi; Watanabe, So; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yuri, Yosuke*; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Koka, Masashi*; Yamada, Naoto*; Hagura, Naoto*
Nuclear Instruments and Methods in Physics Research B, 554, p.165449_1 - 165449_5, 2024/09
Times Cited Count:0 Percentile:0.00(Instruments & Instrumentation)Ion beam induced luminescence analysis of lanthanide complexes in the organic solvents for minor actinides recovery process was carried out to investigate the structures of complexes. In this study, hydrogen ion beam obtained from the single-ended accelerator and argon ion beam obtained from the azimuthally varying field cyclotron were used in Takasaki Ion Accelerators for Advanced Radiation Application in National Institutes for Quantum Science and Technology. In the experiments, ion beam induced luminescence spectra of lanthanide complexes in the organic solvents were measured, and the relationship between the obtained spectra and the structures of complexes was studied.
Arai, Yoichi; Hasegawa, Kenta; Watanabe, So; Watanabe, Masayuki; Minowa, Kazuki*; Matsuura, Haruaki*; Hagura, Naoto*; Katsuki, Kenta*; Arai, Tsuyoshi*; Konishi, Yasuhiro*
Journal of Radioanalytical and Nuclear Chemistry, 333(7), p.3585 - 3593, 2024/07
Times Cited Count:1 Percentile:25.62(Chemistry, Analytical)Nakahara, Masaumi; Watanabe, So; Kimura, Shuya; Sasaki, Misa*; Inagaki, Hiromitsu*; Moriguchi, Tetsuji*
Progress in Nuclear Energy, 172, p.105195_1 - 105195_8, 2024/07
Times Cited Count:1 Percentile:57.00(Nuclear Science & Technology)A novel removal technique with ultrafine bubbles has been proposed for decommissioning of nuclear facilities. The performance of removal technology with ultrafine bubbles was evaluated in the removal experiments with non-radioactive materials, simulated contaminants precipitated Co oxides. To investigate the influence of difference in the chemical forms, the decontamination experiments were carried out with the fuel pin end plugs contaminated radioactive materials in a hot cell.
Kobayashi, Takuma*; Suzuki, Asato*; Nakanuma, Takato*; Sometani, Mitsuru*; Okamoto, Mitsuo*; Yoshigoe, Akitaka; Shimura, Takayoshi*; Watanabe, Heiji*
Materials Science in Semiconductor Processing, 175, p.108251_1 - 108251_7, 2024/06
Times Cited Count:3 Percentile:77.39(Engineering, Electrical & Electronic)Ichikawa, Tsubasa*; Hakoshima, Hideaki*; Inui, Koji*; Ito, Kosuke*; Matsuda, Ryo*; Mitarai, Kosuke*; Miyamoto, Koichi*; Mizukami, Wataru*; Mizuta, Kaoru*; Mori, Toshio*; et al.
Nature Reviews Physics (Internet), 6(6), p.345 - 347, 2024/06
Times Cited Count:7 Percentile:99.15(Physics, Applied)Ishikado, Motoyuki*; Takahashi, Ryuta*; Yamauchi, Yasuhiro*; Nakamura, Masatoshi*; Ishimaru, Sora*; Yamauchi, Sara*; Kawamura, Seiko; Kira, Hiroshi*; Sakaguchi, Yoshifumi*; Watanabe, Masao; et al.
JPS Conference Proceedings (Internet), 41, p.011010_1 - 011010_7, 2024/05
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.
Hasegawa, Kenta; Goto, Ichiro*; Miyazaki, Yasunori; Ambai, Hiromu; Watanabe, So; Watanabe, Masayuki; Sano, Yuichi; Takeuchi, Masayuki
Mechanical Engineering Journal (Internet), 11(2), p.23-00407_1 - 23-00407_8, 2024/04
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
Funakoshi, Tomomasa; Watanabe, So; Arai, Yoichi; Iwamoto, Toshihiro; Watanabe, Masayuki; Nishimoto, Yoshihiro*; Yasuda, Makoto*
Mechanical Engineering Journal (Internet), 11(2), p.23-00445_1 - 23-00445_7, 2024/04
Osawa, Naoki*; Kim, S.-Y.*; Kubota, Masahiko*; Wu, H.*; Watanabe, So; Ito, Tatsuya; Nagaishi, Ryuji
Nuclear Engineering and Technology, 56(3), p.812 - 818, 2024/03
Times Cited Count:2 Percentile:57.00(Nuclear Science & Technology)