Horonobe Underground Research Laboratory Project; Synthesis of Phase II (Construction Phase) investigations to a depth of 350m

Sato, Toshinori  ; Sasamoto, Hiroshi   ; Ishii, Eiichi   ; Matsuoka, Toshiyuki; Hayano, Akira  ; Miyakawa, Kazuya   ; Fujita, Tomoo* ; Tanai, Kenji ; Nakayama, Masashi ; Takeda, Masaki ; Yokota, Hideharu; Aoyagi, Kazuhei  ; Ono, Hirokazu ; Shigeta, Naotaka; Hanamuro, Takahiro  ; Ito, Hiroaki 

The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. This report summarizes the results of the Phase II investigations carried out from April 2005 to June 2014 to a depth of 350m. Integration of work from different disciplines into a "geosynthesis" ensures that the Phase II goals have been successfully achieved and identifies key issues that need to made to be addressed in the Phase II investigations Efforts are made to summarize as many lessons learnt from the Phase II investigations and other technical achievements as possible to form a "knowledge base" that will reinforce the technical basis for both implementation and the formulation of safety regulations.