Current state of the additional geological surveys of crush zones at the fast breeder prototype reactor "Monju" site

Ishimaru, Tsuneari ; Shimada, Koji   ; Sasaki, Akimichi; Tanaka, Yukumo; Miyazaki, Masashi; Yasue, Kenichi; Niwa, Masakazu   ; Sueoka, Shigeru   ; Umeda, Koji; Ikeda, Makinori

The Nuclear Regulation Authority instructed to develop a further additional research plan regarding the crushed zones on the Monju site against the JAEA on September 25. The JAEA developed a research plan in response to this instruction, and, the stripping investigation with expansion of the area, the additional detailed geographical and geological surveys around the mountains/terrace boundary, and the marine seismic surveys in the coastal waters, were conducted. The fracture zones were grouped into 2 systems called -system and -system in the on-site investigation. We examined the cross-cutting relationships and displacements of the fracture zones and confirmed that the -system was formed after the -system. From the investigation results so far, similar to the results of the compilation report of April 31, 2010, no clear evidence was observed to support that on-site crushed zones are active faults.