Development of safety assessment method under uncertainty for Horonobe URL project (Contract research)

Takase, Hiroyasu*; Inagaki, Manabu*; Noguchi, Toshihide*; Shimaoka, Akiko*; Martin, A. J.*; Wakamatsu, Hisanori*; Takase, Kyoko*; Tabara, Michiko*; Matsui, Hiroya 

In this study a systematic approach to explicitly address type and size of uncertainties associated with safety assessment due mainly to incomplete knowledge on a spatially heterogeneous geological environment was developed. In this approach a wide range of model variations including the ones with relatively law plausibility are taken into account so that ambiguity remaining in the knowledge is illustrated, which is a distinctive feature of the approach compared with the conventional methodology where only a limited number of best plausible model variations are considered. The study also proposed an approach to assessing plausibility of each model variation based on multiple pieces of evidence by using evidential support logic (ESL). Furthermore the approach was applied to Horonobe area to demonstrate its applicability to the similar class of geological environment as an example.