Mizunami Underground Research Laboratory project. Plan for fiscal year 2012

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU project is planned in three overlapping phases ; Surface-based Investigation Phase (Phase I), Construction Phase (Phase II) and Operation Phase (Phase III). Currently, the project is under the Construction Phase and the Operation Phase. This document introduces the research and development activities planned for 2012 fiscal year based on the MIU Master Plan updated in 2010, construction plan and research collaboration plan, etc. Observations of hydraulic pressure, groundwater chemistry properties have been continued at the existing boreholes. Borehole investigations are planned to be carried out at the -300m stage in order to characterize rock mechanical properties. As study on engineering technologies for deep underground, validation and evaluation of design methodology, existing and supplementary excavation methods, countermeasures during excavation and safe construction will be carried out based on data obtained during shafts and galleries construction. For Phase III investigations, laboratory tests are planned to be conducted for the development of solute transport conceptual models and observation of solute transport properties. As research collaborations, various experiments and researches are planned to carried out with CRIEPI(Central Research Institute of Electric Power Industry), AIST(National Institute of Advanced Industrial Science and Technology), Nagra(National Cooperative for the Disposal of Radioactive Waste) and other research organizations. For construction plan, horizontal galleries at the GL-500m level will be excavated. (author)