Characterization of water conducting fracture and their long-term behavior in deep crystalline rock; A Case study of the Toki granite

Ishibashi, Masayuki; Ando, Tomomi*; Sasao, Eiji; Yuguchi, Takashi; Nishimoto, Shoji*; Yoshida, Hidekazu*

Oyo Chishitsu, 55(4), p.156 - 165, 2014/10

https://doi.org/10.5110/jjseg.55.156

Understanding of long-term history of water-conducting features such as flow-path fractures is key issue to evaluate deep geological environment for geological disposal of high-level radioactive waste (HLW). Thus, we conducted study on the geological features and the long-term behavior of flow-path fractures based on the data obtained at -300m levels in the Mizunami Underground research laboratory (MIU), central Japan. Total 1670 fractures were mapped in underground gallery at the -300m levels. Flow-path fractures occupy about 11% of all fractures. The flow-path fractures are divided into grout filling fractures and low inflow-rate fractures. All of the grout filling fractures is filled with calcite as fracture filling minerals without conspicuous host rock alteration around fractures. The low inflow-rate fractures possessed similar geological character with the sealed fractures which are not acted as flow-path. The geological character of fracture filling and host tock alteration around fractures indicates the history of the formation at the time of intrusion and emplacement of host granite (Stage I), then filling at hydrothermal event (Stage II), and finally opening and elongation during exhumation stage (Stage III). In conclusion, the present flow-path fractures were formed by opening and/or elongation of pre-existed fractures, which were filled at the hydrothermal event, at the time of exhumation.

Electrically tunable spin injector free from the impedance mismatch problem

Ando, Kazuya*; Takahashi, Saburo; Ieda, Junichi; Kurebayashi, Hidekazu*; Trypiniotis, T.*; Barnes, C. H. W.*; Maekawa, Sadamichi; Saito, Eiji

Nature Materials, 10(9), p.655 - 659, 2011/09

https://doi.org/10.1038/nmat3052

Novel pyroprocess with a high separation efficiency of actinides from lanthanides, 2; Equilibrium distributions of actinides and lanthanides in molten chloride salt and liquid Gallium/Aluminum system

Kitawaki, Shinichi; Nakayoshi, Akira; Kofuji, Hirohide; Murakami, Tsuyoshi*; Sakamura, Yoshiharu*; Iizuka, Masatoshi*; Ando, Hidekazu*; Nohira, Toshiyuki*

no journal, , 

The MA recovery process by dry process was studied for partitioning and transmutation scenario. We measured equilibrium separation factor by the experiments of reduction extraction using liquid Ga/Al and chloride molten salt. The experimental results, as compared with the case of using a liquid Cd, high separation efficiency for the rare earth element was obtained.

Applicability of pyro-reprocessing technologies to the treatment of fuel debris, 2; Electrolytic reduction tests for simulated fuel debris

Sakamura, Yoshiharu*; Uruga, Kazuyoshi*; Ando, Hidekazu*; Kitawaki, Shinichi; Nakayoshi, Akira; Kofuji, Hirohide

no journal, , 

no abstracts in English