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Suyama, Kenya; Gunji, Satoshi; Watanabe, Tomoaki; Araki, Shohei; Fukuda, Kodai; Shimada, Kazuya; Fujita, Tatsuya; Ueki, Taro; Nguyen, H. H.
JAEA-Conf 2024-001, 40 Pages, 2024/07
JAEA-Conf-2024-001.pdf:1.28MB
JAEA-Conf-2024-001-appendix(CD-ROM).zip:163.97MB
The 12th International Conference on Nuclear Criticality Safety (ICNC2023) was held from October 1 to October 6, 2023, at the Sendai International Center (Aobayama, Aoba-ku, Sendai, Miyagi-prefecture 980-0856, Japan), organized by Japan Atomic Energy Agency (JAEA) and co-organized by the Reactor Physics Division of the Atomic Energy Society of Japan (AESJ) and the Nuclear Energy Agency of the Organization for Economic Co-operation and Development (OECD/NEA). 224 presentations passed peer review and 273 technical session registrations, bringing the total number of registered participants to 289, including accompanying persons. Technical tours were also conducted to i) Fukushima Daiichi Nuclear Power Station of TEPCO holdings and Interim Storage Facility Information Center, ii) Nuclear Science Research Institute of JAEA (STACY Renewable Reactor and FCA), iii) NanoTerasu of Tohoku University (synchrotron radiation facility) and Onagawa Nuclear Power Station of Tohoku Electric Power Co., Inc. This report summarizes the conference and compiles the papers that were presented and agreed to be published in the Proceedings.
Shimada, Kazuya; Ishizuka, Chikako*; Chiba, Satoshi*
Proceedings of 12th International Conference on Nuclear Criticality Safety (ICNC2023) (Internet), 9 Pages, 2023/10
TKE (total kinetic energy), one of the nuclear data, is the kinetic energy of fission fragments, and influences not only the energy obtained in nuclear fission, but also the criticality safety assessment. Exploring the underlying factors influencing TKE is vital for fundamental research and utilization of nuclear energy. Instinctively, it is expected that as the energy of incident neutrons on the target nucleus increases, thus leading to a corresponding increase in TKE. However, experimental evidence suggests that TKE decreases as the excitation energy increases. In this study, we investigate this phenomenon. The four-dimensional Langevin model captures the overall shape of the nuclear fission fragment as Brownian motion until the nuclear fission. Using this model, we calculated the excitation energy dependence of TKE. Our investigation reveals that the decreasing trend in TKE can be attributed to the deformation of the heavy fission fragments.
Shimada, Taro; Takubo, Kazuya*; Takeda, Seiji; Yamaguchi, Tetsuji
Progress in Nuclear Science and Technology (Internet), 5, p.183 - 187, 2018/11
After fuel debris is removed from the reactor containment vessel at Fukushima Daiichi NPS (1F) and collected in waste containers in the future, the waste containers will be disposed at a deep geological repository. The uranium inventory and uranium-235 (
U) enrichment of the fuel debris are larger than those of high-level vitrified wastes which are produced from liquid waste during reprocessing of spent nuclear fuels. Therefore, there is a possibility not to be excluded that a criticality occurs in the geological media where the uranium precipitates at the far-field from the repository, after the uranium located in the repository is dissolved by groundwater. In this study, we calculated the quantity of uranium precipitated at the natural barrier, and studied dimension of uranium deposited in the natural barrier and carried out the criticality analysis.
Shimada, Taro; Takeda, Seiji; Sakai, Ryutaro*; Takubo, Kazuya; Tanaka, Tadao
MRS Advances (Internet), 1(61), p.4081 - 4086, 2016/00
Volcanic eruption which may affect geological disposal system directly depends on the regional location in Japan. It is required that the disposal site should be located far from existing volcanos. However, there are regions where it is impossible to exclude the possibility of appearance of new volcanic activity on the site even if the site is located far from existing volcanos. In order to identify the influence of volcanic eruption at disposal site to public if it occurs public exposure doses were evaluated based on the two scenarios considering types of eruption at new volcanic activity in Japan. One is the exposure by tephra widespread by Strombolian eruption and deposited on the ground surface, including radionuclides from vitrified waste forms after a volcanic conduit penetrated disposal galleries. The other is that by waste forms appeared at the surface by Merapi type pyroclastic flow. Exposure doses of the residents living on the tephra do not exceed 1mSv/y even when the eruption occurs at 1,000 years after closure of disposal site. Dose rate for the volcanic researchers temporarily approaching waste forms becomes less than 1mSv/h when the eruption occurs 100,000 years after. It indicated that attention should be paid to the impact by Merapi type pyroclastic flow on researchers approaching waste forms appeared rather than that by Strombolian eruption on residents living on the tephra widespread.
Al conductor for coils with react-and-wind methodKizu, Kaname; Tsuchiya, Katsuhiko; Shimada, Katsuhiro; Ando, Toshinari*; Hishinuma, Yoshimitsu*; Koizumi, Norikiyo; Matsukawa, Makoto; Miura, Yushi*; Nishimura, Arata*; Okuno, Kiyoshi; et al.
Fusion Engineering and Design, 82(5-14), p.1493 - 1499, 2007/10
Times Cited Count：3 Percentile：24.10(Nuclear Science & Technology)no abstracts in English
Tsuzuki, Kazuhiro; Kamiya, Kensaku; Shinohara, Koji; Bakhtiari, M.*; Ogawa, Hiroaki; Kurita, Genichi; Takechi, Manabu; Kasai, Satoshi; Sato, Masayasu; Kawashima, Hisato; et al.
Nuclear Fusion, 46(11), p.966 - 971, 2006/11
Times Cited Count：16 Percentile：45.63(Physics, Fluids & Plasmas)no abstracts in English
Al strand and cable-in-conduit conductorKizu, Kaname; Tsuchiya, Katsuhiko; Shimada, Katsuhiro; Ando, Toshinari*; Hishinuma, Yoshimitsu*; Koizumi, Norikiyo; Matsukawa, Makoto; Miura, Yushi*; Nishimura, Arata*; Okuno, Kiyoshi; et al.
IEEE Transactions on Applied Superconductivity, 16(2), p.872 - 875, 2006/06
Times Cited Count：1 Percentile：11.63(Engineering, Electrical & Electronic)no abstracts in English
Tsuzuki, Kazuhiro*; Kimura, Haruyuki; Kusama, Yoshinori; Sato, Masayasu; Kawashima, Hisato; Kamiya, Kensaku; Shinohara, Koji; Ogawa, Hiroaki; Uehara, Kazuya; Kurita, Genichi; et al.
Fusion Science and Technology, 49(2), p.197 - 208, 2006/02
Times Cited Count：11 Percentile：57.88(Nuclear Science & Technology)no abstracts in English
Tsuzuki, Kazuhiro; Shinohara, Koji; Kamiya, Kensaku; Kawashima, Hisato; Sato, Masayasu; Kurita, Genichi; Bakhtiari, M.; Ogawa, Hiroaki; Hoshino, Katsumichi; Kasai, Satoshi; et al.
Journal of Nuclear Materials, 329-333(1), p.721 - 725, 2004/08
Times Cited Count：7 Percentile：43.26(Materials Science, Multidisciplinary)no abstracts in English
Tsuzuki, Kazuhiro; Kimura, Haruyuki; Kawashima, Hisato; Sato, Masayasu; Kamiya, Kensaku; Shinohara, Koji; Ogawa, Hiroaki; Hoshino, Katsumichi; Bakhtiari, M.; Kasai, Satoshi; et al.
Nuclear Fusion, 43(10), p.1288 - 1293, 2003/10
Times Cited Count：40 Percentile：72.60(Physics, Fluids & Plasmas)no abstracts in English
Kato, Takashi; Tsuji, Hiroshi; Ando, Toshinari; Takahashi, Yoshikazu; Nakajima, Hideo; Sugimoto, Makoto; Isono, Takaaki; Koizumi, Norikiyo; Kawano, Katsumi; Oshikiri, Masayuki*; et al.
Fusion Engineering and Design, 56-57, p.59 - 70, 2001/10
Times Cited Count：18 Percentile：74.95(Nuclear Science & Technology)no abstracts in English
Terakado, Tsunehisa; Okano, Jun; Shimada, Katsuhiro; Miura, Yushi; Yamashita, Yoshiki*; Matsukawa, Makoto; Hosogane, Nobuyuki; Tsuji, Hiroshi; Ando, Toshinari*; Takahashi, Yoshikazu; et al.
JAERI-Tech 2001-056, 24 Pages, 2001/08
JAERI-Tech-2001-056.pdf:1.17MB
no abstracts in English
Shimada, Taro; Takubo, Kazuya; Takeda, Seiji; Tanaka, Tadao
no journal, ,
In long-term safety assessment of geological disposal system, it is necessary to evaluate the impact on the nuclides migration where groundwater flow and water composition are changed with decreasing a depth of the repository by uplifts and denudation. Therefore, we developed an integrated safety assessment methodology for uplifts and denudation where nuclides migration was evaluated reflecting temporal and spatial changes of parameters of natural and engineered barriers such as distribution coefficient, porosity and groundwater velocity, which were obtained by calculation of groundwater flow, salt water distribution and long-term transition of engineered barriers. The methodology was applied to an assumed disposal site composed of sedimentary rocks with uplift and denudation. Migration parameters of engineered barrier such as coefficient of water permeability and porosity of buffer material were evaluated considering the interaction between overpack and surrounding bentonite clay under the condition of water composition. Migration parameters of the natural barrier such as distribution coefficient were determined by the combination of the geology section and water composition section on the migration pathway from the repository to the outlet of the natural barrier at the depth of 40m from the surface. The migration fluxes of some radionuclides at the outlet of natural barrier were evaluated and then the impacts on nuclides migration by uplifts and denudation were compared.
Al CIC conductor measured with spring methodKizu, Kaname; Ando, Toshinari*; Tsuchiya, Katsuhiko; Shimada, Katsuhiro; Matsukawa, Makoto; Tamai, Hiroshi; Koizumi, Norikiyo; Okuno, Kiyoshi; Nishimura, Arata*; Hishinuma, Yoshimitsu*; et al.
no journal, ,
no abstracts in English
Araki, Shohei; Shimada, Kazuya; Gunji, Satoshi
no journal, ,
no abstracts in English
Gunji, Satoshi; Araki, Shohei; Shimada, Kazuya; Yoshikawa, Tomoki; Hasegawa, Kenta; Aizawa, Eiju; Ishii, Junichi; Izawa, Kazuhiko; Araki, Masaaki
no journal, ,
no abstracts in English
Shimada, Kazuya; Nguyen, H. H.; Araki, Shohei; Suyama, Kenya; Izawa, Kazuhiko; Gunji, Satoshi
no journal, ,
no abstracts in English
Shimada, Kazuya; Araki, Shohei; Suyama, Kenya; Izawa, Kazuhiko; Gunji, Satoshi
no journal, ,
In the basic experiments at the modified STACY, critical water levels were measured with varying numbers of fuel rods. In this study, the effective multiplication factors were calculated for the experimental critical water levels. MVP3 and MCNP6 have been used in the previous analysis of STACY, and the SCALE6 was additionally used to compare the calculation results. I investigated whether the deviation in the effective multiplication factor obtained here was larger than the uncertainty in critical water level measurement. When critical water level is low, for example about 450 mm, the effective multiplication factors were within the uncertainty in critical water level measurement. On the other hand, when critical water level is high, for example about 1200 mm, the effective multiplication factors were widely distributed outside the uncertainty in critical water level measurement.
Shimada, Kazuya; Suyama, Kenya
no journal, ,
In fuel debris systems where water and fuel are mixed, their spatial configuration affects the effective multiplication factor. For critical safety management of debris, we examined indicators relating spatial configuration to effective multiplication factor k
, with the long-term goal of quantifying this relationship. Initially targeting critical experiments with fuel rods randomly arranged on lattices, we proposed an indicator h for debris applications without geometric constraints like lattice arrangements. This indicator is defined from nearest-neighbor distance distributions of fuel rods, inspired by pair distribution functions in materials science. To validate this indicator, we confirmed correlations in simplified lattice systems. Results showed negative correlations between h and k, suggesting the indicator's potential. Future work will examine systems without lattice constraints.
Al strand and cable-in-conduit conductorKizu, Kaname; Ando, Toshinari*; Okuno, Kiyoshi; Koizumi, Norikiyo; Shimada, Katsuhiro; Seo, Kazutaka*; Takahata, Kazuya*; Tamai, Hiroshi; Tsuchiya, Katsuhiko; Nishimura, Arata*; et al.
no journal, ,
no abstracts in English
