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Oe, Toshiaki*; Wakasugi, Keiichiro
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 24(1), p.27 - 32, 2017/06
The report estimates the life-time of the waste glass dissolution in the geologic disposal environment. The overall safety report on the geologic disposal in Japan showed very short life-time of approximately 70,000 years under pessimistic assumptions ignoring the temperature decrease due to radioactive decay and dissolution rate reduction due to surface shrinkage. These factors are physically established phenomena and may not be excluded. The dissolution models including these factors of temperature and surface area decreases are discussed and used for re-evaluation. Three fracture models are presented for evaluating the surface area decreases; a single plate, monotonic spheres, spheres having power-law distribution. All models have the same initial volume as the waste glass block for mass conservation and the total surface areas are 10 times higher than the initial pristine block because of the fracture development during production. The results indicate the retention time of 50% of initial mass exceed 100,000 years even by different fracture models and the dissolution life-times are expected for 260,000700,000 years depending on models. These results imply more strong isolation capability of the waste glass than that estimated in the overall safety report.
Takahashi, Yuta*; Oe, Toshiaki*; Wakasugi, Keiichiro
Tokai Daigaku Kiyo Kogakubu, 56(2), p.21 - 26, 2016/00
Hirano, Fumio; Sato, Seichi*; Kozaki, Tamotsu*; Inagaki, Yaohiro*; Iwasaki, Tomohiko*; Oe, Toshiaki*; Kato, Kazuyuki*; Kitayama, Kazumi*; Nagasaki, Shinya*; Niibori, Yuichi*
Journal of Nuclear Science and Technology, 49(3), p.310 - 319, 2012/03
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)The thermal impacts of hull and end piece wastes from the reprocessing of MOX spent fuels burned in LWRs on repository performance were investigated. The heat generation rates in MOX spent fuels and the resulting heat generation rates in hull and end piece wastes change depending on the fuel histories including the burn-up of UO spent fuels, the cooling period before reprocessing, the storage period of fresh MOX fuels. The heat generation rates of hull and end piece wastes from the reprocessing of MOX spent fuels with any of those histories are significantly larger than those from UO spent fuels with burn-ups of 45 GWd/THM. If a temperature below 80C is specified for cement-based materials used in waste packages after disposal, the allowable number of canisters containing compacted hull and end pieces in a package for 45 GWd-MOX needs to be limited to a value of 0.7 to 1.6, which is significantly lower than the value of 4.0 for 45 GWd-UO.
Nakayama, Shinichi; Nagasaki, Shinya*; Inagaki, Yaohiro*; Oe, Toshiaki*; Sasaki, Takayuki*; Sato, Seichi*; Sato, Tsutomu*; Tanaka, Satoru*; Tochiyama, Osamu*; Nagao, Seiya*; et al.
JAEA-Conf 2007-003, 120 Pages, 2007/03
The 1st information exchange meeting on Radioactive Waste Disposal Research Network was held in Nuclear Science Research Institute of Japan Atomic Energy Agency on August 4, 2006. Radioactive Waste Disposal Research Network was established by under Interorganization Atomic Energy Research Program of Japan Atomic Energy Agency, and the objective is to bring both research infrastructures and human expertise in Japan to an adequate performance level, thereby contributing to the development of the fundamental research area in the field of radioactive waste disposal. This lecture material is a collection of research presentations and discussions during the information exchange meeting.
Oe, Toshiaki*; Yamaguchi, Tetsuji
Nihon Genshiryoku Gakkai-Shi, 40(1), p.47 - 49, 1998/01
no abstracts in English
Tanaka, Satoru*; Nagasaki, Shinya*; *; *; Muraoka, Susumu; *; *; *; *; *; et al.
Nihon Genshiryoku Gakkai-Shi, 39(12), p.1008 - 1018, 1997/00
Times Cited Count:3 Percentile:30.38(Nuclear Science & Technology)no abstracts in English
*; *; *; *; Sakamoto, Yoshiaki; *; *; ; Nagasaki, Shinya*; *; et al.
Nihon Genshiryoku Gakkai-Shi, 37(1), p.59 - 77, 1995/00
Times Cited Count:12 Percentile:74.13(Nuclear Science & Technology)no abstracts in English
*; *; *; *; *; *; ; Nagasaki, Shinya*
Nihon Genshiryoku Gakkai-Shi, 35(5), p.420 - 437, 1993/05
Times Cited Count:6 Percentile:56.02(Nuclear Science & Technology)no abstracts in English
; *; *; *; *; *; Kimura, Hideo; Munakata, Masahiro
Nihon Genshiryoku Gakkai-Shi, 34(4), p.342 - 364, 1992/04
Times Cited Count:2 Percentile:27.5(Nuclear Science & Technology)no abstracts in English
Yoshiki, Nobuya*; Oe, Toshiaki*; Tsukamoto, Masaki*; Tanaka, Hiroshi*
JNC TJ1400 2005-003, 149 Pages, 1990/03
None
Sekioka, Yasushi; Takeda, Seiji; Kimura, Hideo; Yamaguchi, Tetsuji; Oe, Toshiaki*; Nagasaki, Shinya*; Sasaki, Takayuki*; Kozaki, Tamotsu*; Inagaki, Yaohiro*
no journal, ,
no abstracts in English
Oe, Toshiaki*; Nagasaki, Shinya*; Kimura, Hideo; Takeda, Seiji; Sekioka, Yasushi; Kato, Hiroyasu*; Akahori, Kuniaki*
no journal, ,
no abstracts in English
Uchida, Masahiro; Amano, Kenji; Hama, Katsuhiro; Takeuchi, Ryuji; Yoshida, Takuma*; Noshita, Kenji*; Futakuchi, Katsuhito*; Oe, Toshiaki*; Nagasaki, Shinya*
no journal, ,
no abstracts in English
Oe, Toshiaki*; Nagasaki, Shinya*; Kimura, Hideo; Takeda, Seiji; Sekioka, Yasushi; Kato, Hiroyasu*
no journal, ,
no abstracts in English
Hama, Katsuhiro; Uchida, Masahiro; Amano, Kenji; Takeuchi, Ryuji; Hagiwara, Hiroki; Yoshida, Takuma*; Noshita, Kenji*; Nagasaki, Shinya*; Oe, Toshiaki*; Futakuchi, Katsuhito*
no journal, ,
The micro-chemical probe for characterization of geological environment has been developed. The performance test shows that this equipment can be applicable for the in-situ experiment.
Oe, Toshiaki*; Suzuki, Masashi*; Tachi, Yukio; Kato, Hiroyasu*
no journal, ,
Physico-chemical properties of pore water in water saturated compacted bentonite was investigated by the osmotic pressure measurement. Osmotic pressure reached the peak value at dry density of 1.2 g/cm, implying that physico-chemical properties change drastically at this desity.
Mitsui, Seiichiro; Oe, Toshiaki*; Inagaki, Yaohiro*; Okubo, Takahiro*; Kurosawa, Susumu*; Goto, Takahiro*; Inagaki, Manabu*; Ishiguro, Katsuhiko*; Takase, Hiroyasu*; Takahashi, Hirokazu*
no journal, ,
In order to develop robust performance assessment models, we have been preparing an information basis regarding glass properties and glass dissolution/alteration processes under disposal conditions as a part of NUMO-JAEA joint project. Our iterative working process for the preparation of the information basis comprises five steps: (1) integration of current knowledge; (2) development of glass dissolution scenarios based on current knowledge; (3) development of conceptual model; (4) sensitivity analyses to evaluate relative importance of relevant processes and associated uncertainties; and (5) identification of future R&D issues towards further improvement of the information basis. The current status will be presented in this talk.