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Maeda, Toshikatsu; Tanaka, Tadao; Mukai, Masayuki; Ogawa, Hiromichi; Yamaguchi, Tetsuji; Munakata, Masahiro; Matsumoto, Junko; Kozai, Naofumi; Bamba, Tsunetaka; Fan, Z.*; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.336 - 341, 2003/09
no abstracts in English
Futakuchi, Katsuhito*; Hashimoto, Shuji*; Sakuramoto, Yuji*; ; Kamei, Gento
JNC TN8400 2001-007, 52 Pages, 2001/04
JNC-TN8400-2001-007.pdf:2.34MB
As a natural analogue, the authors investigted a Tertiary argillaceous bed and a Quarternary hypabyssal rock (porphyrite) which intruded into the argillaceous rock, distributed in the Nishikubiki district of Niigata prefecture in Japan. We examined the variation of clay mineral species in the argillaceous rock surrounding the intrusive rock and carried out thermal analyses for the argillaceous rock based on the coolig history of the intrusive rock. The predominant clay mineral varied from montmorillonite to illite through illite/montmorillonite interlayers with approaching to the intrusive rock. The thermal analyses indicated that the temperature descended from 270 to 15 
C during the 7.5
10
years at alocalty of argillaceous rock containing 75% illite in the interlayers. On the assumption that the alteration from montmorillonite to illite was regarded as a first-order reaction, we evaluated the apparent activation energy based on the thermal condition mentioned above; about 103 kJ/mol was obtained for this illitization. This was within the range of values reported previously by laboratory experiments and/or examinations of natural illitizations.
Chijimatsu, Masakazu*; Fujita, Tomoo; Sugita, Yutaka; Taniguchi, Wataru
JNC TN8400 2000-008, 339 Pages, 2000/01
JNC-TN8400-2000-008.pdf:30.96MB
Geological disposal of high-level radioactive waste (HLW) in Japan is based on a multibarrier system composed of engineered and natural barriers. The engineered barriers are composed of vitrified waste confined within a canister, overpack and buffer material. Highly compacted bentonite clay is considered one of the most promising candidate buffer material mainly because of its low hydraulic conductivity and high adsorption capacity of radionuclides. In a repository for HLW, complex thermal, hydraulic and mechanical (T-H-M) phenomena will take place, involving the interactive processes between radioactive decay heat from the vitrified waste, infiltration of ground water and stress generation due to the earth pressure, the thermal loading and the swelling pressure of the buffer material. In order to evaluate the performance of the buffer material, the coupled T-H-M behaviors within the compacted bentonite have to be modelled. Before establishing a fully coupled T-H-M model, the mechanism of each single Phenomenon or partially coupled phenomena should be identified. Furthermore, in order to evaluate the coupled T-H-M phenomena, the analysis model was developed physically and numerically and the adequacy and the applicability was tested though the engineered scale laboratory test and in-situ test. In this report, the investigative results for the development of coupled T-H-M model were described. This report consists of eight chapters. In Chapter l, the necessity of coupled T-H-M model in the geological disposal project of the high-level radioactive waste was described. In Chapter 2, the laboratory test results of the rock sample and the buffer material for the coupled T-H-M analysis were shown. The rock samples were obtained from the in-situ experimental site at Kamaishi mine. As the buffer material, bentonite clay (Kunigel V1 and Kunigel OT-9607) and bentonite-sand mixture were used. In Chapter 3, in-situ tests to obtain the rock property were shown. As ...
Ishikawa, Kiyoshi*; Mezaki, Yoshihiko*; Suzuki, Hideo*; Kai, Masanori*; Watanabe, Hajime*; Fujimori, Seiji*; Ishikawa, Junichi*
JNC TJ7420 99-016, 878 Pages, 1999/06
no abstracts in English
Matsui, Hiroya; Ozaki, Yusuke; Kimoto, Kazushi*; Ichikawa, Yasuaki*
no journal, ,
The quantitative estimation of the time dependent behavior of a host rock is important to confident the design of a plug in HLW repository. On the other hand, interaction between rock and groundwater may affect with the time dependent behavior. Therefore, it is need to establish the model such a coupling process and estimate a distribution of micro crack in rock quantitatively. The paper report the results of the study on evaluation of the properties of a crystalline rock using of surface wave for these purpose.
