Macroscopically and microscopically research about structure of faults at a repository scale

not registered; not registered; Morooka, Koichi*

This study is an object to collect and arrange data about the mass transfer path during a natural barrier system by grasping actual rock feature, in order to be useful for a performance assessment of a natural barrier system at geological disposal of HLW. An existence of permeability high large-scale faults extends a large influence over a performance assessment of geological disposal. With "The Second Progress Report on Research and Development for the Geological Disposal of HLW in Japan" which Nuclear Cycle Development Institute (JNC) issued, it is as" A repository would be located at least 100 meters away from major faults and major fracture zones which could adversely affect the stability and performance of the repository" as a Reference Case concept model of a natural barrier system, Then, they are as "in the Reference Case, the transport path consists of the host rock and the downstream fault". It will not be easy to know the distribution of faults in the subsurface deep division without data acquired from many boreholes and underground laboratory. With this study, specific data on the large-scale faults and fracture zones has been collected and arranged by investigating in underground galleries and on the literatures of a post-operated mine site. Based on this result, a consideration on the principal transfer pass at a natural barrier system has been conducted. The contents conducted in this report is the follows. (1)investigation of literature about data of fracture, shear zone, and geology, (2)field investigation of fracture and shear zone in the rock, (3)arrangement of these results, (4)modeling of the major water conductive feature, and (5)evaluation of an assumption which has been introduced in the Second Progress Report issued by JNC.