Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage; Progress report on NUMO-JAEA collaborative research in FY2011 (Joint research)

Shibata, Masahiro ; Sawada, Atsushi ; Tachi, Yukio  ; Makino, Hitoshi ; Hayano, Akira  ; Mitsui, Seiichiro  ; Taniguchi, Naoki ; Oda, Chie  ; Kitamura, Akira  ; Osawa, Hideaki  ; Semba, Takeshi ; Hioki, Kazumasa ; Kamei, Gento ; Ebashi, Takeshi*; Kubota, Shigeru*; Kurosawa, Susumu*; Goto, Junichi*; Goto, Takahiro*; Ishii, Eiichi*   ; Inagaki, Manabu*; Moriya, Toshifumi*; Suzuki, Satoru*; Oi, Takao* ; Ichihara, Takayuki*; Ishida, Keisuke*; Ishiguro, Katsuhiko*; Tsuchi, Hiroyuki*

JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation phase. The topics and the conducted research are follows; (1) Study on selection of host rock: in terms of hydraulic properties, items for assessing rock property, and assessment methodology of groundwater travel time has been organized with interaction from site investigation. (2) Study on development of scenario: the existing approach has been embodied, in addition, the phenomenological understanding regarding dissolution of and nuclide release from vitrified waste, corrosion of the overpack, long-term performance of the buffer are summarized. (3) Study on setting nuclide migration parameters: the approach for parameter setting has been improved for sorption and diffusion coefficient of buffer/rock, and applied and tested for parameter setting of key radionuclides. (4) Study on ensuring quality of knowledge: framework for ensuring quality of knowledge has been studied and examined aimed at the likely disposal facility condition.