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Collaborative Laboratories for Advanced Decommissioning Science; Institute of Science Tokyo*
JAEA-Review 2025-016, 143 Pages, 2025/10
JAEA-Review-2025-016.pdf:10.71MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2023. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (hereafter referred to "1F"), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Challenge of novel hybrid-waste-solidification of mobile nuclei generated in Fukushima Nuclear Power Station and establishment of rational disposal concept and its safety assessment" conducted from FY2021 to FY2023. This study aims to establish the rational waste disposal concept of various wastes generated in 1F based on the hybrid-waste-solidification by the Hot Isostatic Press (HIP) method. The ceramics form with target elements, mainly iodine, which is challenging to immobilize, and Minor Actinides such as Am, an alpha emitter and heat source, are HIPed with well-studied materials such as SUS and zircaloy, which make the long-term stability evaluation and safety assessment possible. In 2024, the project's final year, we demonstrated the effectiveness of the hybrid solidification concept by linking all the sub-themes, from waste synthesis to disposal considerations. The compatibility of various wastes, such as ALPS, AREVA sediment wastes, AgI, waste silver adsorbent, ceria adsorbent, and iodine apatite, with metals and oxide matrices was investigated. which involves investigating the HIPed hybrid wastes after exploring the compatibility of various metals and oxide matrices using the rapid sintering method, spark plasma sintering (SPS), proposed in this project. It revealed that hybrid waste solidification with SUS matrix was superior for many wastes. Furthermore, we studied waste disposal concepts based on nuclide migration calculations. Finally, we could connect the waste fabrication to safety assessment for the first time, leading to finding an appropriate waste disposal scenario for 1F decommissioning.
Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*
JAEA-Review 2024-012, 122 Pages, 2024/09
JAEA-Review-2024-012.pdf:6.31MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2022. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station (hereafter referred to "1F"), Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2021, this report summarizes the research results of the "Challenge of novel hybrid-waste-solidification of mobile nuclei generated in Fukushima Nuclear Power Station and establishment of rational disposal concept and its safety assessment" conducted in FY2022. The present study aims to establish the rational waste disposal concept of a variety of wastes generated in 1F based on the hybrid-waste-solidification by the Hot Isostatic Press (HIP) method. The ceramics form with target elements, mainly iodine, which is difficult to immobilize, and Minor actinides such as Am, an alphaemitter and heat source, are HIPed with well-studied materials such as SUS and zircaloy, which make the long-term stability evaluation and safety assessment possible.
analyses with ferromagnetic and plasma rotation effects and wall geometry for a high steady state tokamakKurita, Genichi; Bialek, J.*; Tsuda, Takashi; Azumi, Masafumi*; Ishida, Shinichi; Navratil, G. A.*; Sakurai, Shinji; Tamai, Hiroshi; Matsukawa, Makoto; Ozeki, Takahisa; et al.
Nuclear Fusion, 46(2), p.383 - 390, 2006/02
Times Cited Count：9 Percentile：29.71(Physics, Fluids & Plasmas)It is shown that critical beta is decreased by ferromagnetic effect by about 8% for 
/
2, and denoting the permeability of ferromagnetic wall and vacuum, respectively, for tokamak of aspect ratio 3. The existence of the stability window for resistive wall mode opened by both effects of the toroidal plasma rotation and the plasma dissipation, which was not observed for high aspect ratio tokamak, is found for tokamak of aspect ratio 3. The effect of ferromagnetism on them is also investigated. The critical beta analyses of NCT (National Centralized Tokamak) plasma using VALEN code are started with stabilizing plate and vacuum vessel geometry with finite resistivity, and the results for passive effect of stabilizing plate are obtained. The calculations including stabilizing effect of the vacuum-vessel and also active feedback control are also performed for present design of NCT plasma.
plasma operationTamai, Hiroshi; Akiba, Masato; Azechi, Hiroshi*; Fujita, Takaaki; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; Hosogane, Nobuyuki; Ichimura, Makoto*; et al.
Nuclear Fusion, 45(12), p.1676 - 1683, 2005/12
Times Cited Count：15 Percentile：44.03(Physics, Fluids & Plasmas)Design studies are shown on the National Centralized Tokamak facility. The machine design is carried out to investigate the capability for the flexibility in aspect ratio and shape controllability for the demonstration of the high-beta steady state operation with nation-wide collaboration, in parallel with ITER towards DEMO. Two designs are proposed and assessed with respect to the physics requirements such as confinement, stability, current drive, divertor, and energetic particle confinement. The operation range in the aspect ratio and the plasma shape is widely enhanced in consistent with the sufficient divertor pumping. Evaluations of the plasma performance towards the determination of machine design are presented.
Matsumoto, Taro; Naito, Hiroshi*; Tokuda, Shinji; Kishimoto, Yasuaki*
Nuclear Fusion, 45(11), p.1264 - 1270, 2005/11
Times Cited Count：15 Percentile：44.03(Physics, Fluids & Plasmas)A gyrokinetic particle simulation is executed to clarify the effect of the electron inertia on the MHD phenomena in the reversed shear configuration (RSC) of a cylindrical tokamak plasma. It is found that the collisionless (kinetic) double tearing modes grow up at the Alfv
n time scale, and nonlinearly induce the internal collapse when the helical flux at the magnetic axis is less than that at the outer resonant surface. After the internal collapse, the secondary reconnection is induced by the current concentration due to the 
convective flow. It is also clarified that a nonlinear dynamics accompanied with the elementary processes caused by the flow can generate a new RSC with resonant surfaces. In the presence of the density gradient, after the full reconnection induced by the mode, the radial electric field is found to be generated due to the difference of the 
motion between ions and electrons. However, the intensity of the radial field is not so large as that induced by the collisionless kink mode.
Kurita, Genichi; Tsuda, Takashi; Azumi, Masafumi; Ishida, Shinichi; Takeji, Satoru*; Sakasai, Akira; Matsukawa, Makoto; Ozeki, Takahisa; Kikuchi, Mitsuru
Nuclear Fusion, 43(9), p.949 - 954, 2003/09
Times Cited Count：32 Percentile：66.52(Physics, Fluids & Plasmas)In order to improve economic and environmental suitability of tokamak fusion reactors, both the accomplishment of high beta plasmas and the practical use of low activation materials to reduce the amount of radioactive waste are crucially important. Low radio-activation ferritic steel is considered as a most promising candidate for structural material in DEMO reactors, and there is the possibility of reduction of critical beta value by the deterioration of MHD stability due to ferromagnetism of ferritic steel. This paper investigates the effect of ferromagnetism with plasma flow on the beta limit of tokamak plasma by carrying out MHD stability analyses including ferromagnetic and plasma flow effects.
Utsumi, Takayuki*; Koga, J. K.; Kunugi, Tomoaki*
Parallel Computational Fluid Dynamics; New Frontiers and Multi-Disciplinary Applications, p.539 - 546, 2003/00
no abstracts in English
n eigenmodes in tokamak plasmasFukuyama, Atsushi*; Ozeki, Takahisa
Purazuma, Kaku Yugo Gakkai-Shi, 75(5), p.537 - 547, 1999/05
no abstracts in English
; Takizuka, Tomonori; Hatayama, Akiyoshi*;
Journal of Nuclear Materials, 266-269, p.526 - 531, 1999/00
Times Cited Count：4 Percentile：34.08(Materials Science, Multidisciplinary)no abstracts in English
; Kunugi, Tomoaki; Koga, J. K.
Computer Physics Communications, 108(2-3), p.159 - 179, 1998/00
Times Cited Count：15 Percentile：63.72(Computer Science, Interdisciplinary Applications)no abstracts in English
Yamagiwa, Mitsuru; Hirose, A*; Elia, M.*
PPL-163, 22 Pages, 1997/01
no abstracts in English
Yamagiwa, Mitsuru; Hirose, A*; Elia, M.*
Plasma Physics and Controlled Fusion, 39(3), p.531 - 540, 1997/00
Times Cited Count：6 Percentile：23.85(Physics, Fluids & Plasmas)no abstracts in English
Tokuda, Shinji;
JAERI-Research 96-044, 102 Pages, 1996/08
JAERI-Research-96-044.pdf:2.3MB
no abstracts in English
Yoshino, Ryuji; Neyatani, Yuzuru; Isei, Nobuaki; Koide, Yoshihiko; Kawano, Yasunori; A.Tanga*; Campbell, D. J.*; M.F.Johnson*; L.Rossi*
IAEA-CN-60/A5-8, 0, p.685 - 695, 1995/00
no abstracts in English
Yamagiwa, Mitsuru
Nuclear Fusion, 35(10), p.1225 - 1230, 1995/00
Times Cited Count：0 Percentile：0.00(Physics, Fluids & Plasmas)no abstracts in English
D.A.Humphreys*; Yoshino, Ryuji
JAERI-M 92-069, 25 Pages, 1992/05
no abstracts in English
Azumi, Masafumi; Hasegawa, Mitsuru*; ; Kurihara, Kenichi; Nakamura, Yukiharu; Nishio, Satoshi; Shimomura, Yasuo; Shinya, K.*; Sugihara, Masayoshi; ; et al.
JAERI-M 92-041, 100 Pages, 1992/03
no abstracts in English
Ozeki, Takahisa; Azumi, Masafumi; Kamada, Yutaka; Yoshino, Ryuji; Tokuda, Shinji; Tsunematsu, Toshihide; Nagashima, Keisuke; Yoshida, Hidetoshi;
Nuclear Fusion, 31(1), p.51 - 60, 1991/00
Times Cited Count：8 Percentile：40.82(Physics, Fluids & Plasmas)no abstracts in English
Ozeki, Takahisa; M.S.Chu*; L.L.Lao*; T.S.Taylor*; M.S.Chance*; ; K.H.Burrell*; R.D.Stambaugh*
Nuclear Fusion, 30(8), p.1425 - 1432, 1990/08
Times Cited Count：122 Percentile：93.17(Physics, Fluids & Plasmas)no abstracts in English
Takeda, Tatsuoki; Tsunematsu, Toshihide; ; ;
Computational Mechanics 86;Theory and Applications, p.9 - 3, 1986/00
no abstracts in English
