Master plan of the Mizunami Underground Research Laboratory Project

Tono Geoscientific Research Unit, Geological Isolation Research and Development Directorate

The Japan Atomic Energy Agency is implementing scientific studies of the deep geological environment and development of technologies to enhance the reliability of geological disposal technology ('geoscientific research') at Mizunami Underground Research Laboratory (MIU). The aims of the MIU Project are to establish techniques for investigation, analysis and assessment of the deep geological environment, and to develop a range of engineering techniques for deep underground application, with main focus on the crystalline rock with fresh ground-water condition. The master plan of the MIU project has been revised several times since 1996, reflecting the revision of "Long-term plan for Research, Development and Utilization of Nuclear Energy" and relocation of the research site. In 2009, revisions of the basic policy about fundamental strategy for geological disposal have resulted in the extension of the time range to reach the milestone on the establishment of methodologies for the detailed investigation. On the other hand, increasing role of the underground research facility as a platform for achieving the public acceptance of the geological disposal has been recognized. Thus JAEA has intended to construct an additional research gallery at a depth of 300m of the MIU and to revise the master plan therein. In this revision, major results of the Phase I(surface-based investigation) have highlighted and investigations for the Phase II (construction) and Phase III (operation) are restructured from the view point of their relative importance to the implementation of the geological disposal programme.