Study on evaluation method of potential impact of natural phenomena on a HLW disposal system

Japan Atomic Energy Agency (JAEA) have developed a formal evaluation method to assess the potential impact of natural phenomena (earthquakes and faulting; volcanism; uplift, subsidence, denudation and sedimentation; climatic and sea-level changes) on a high level radioactive waste (HLW) disposal system. This study focuses on identifying key T-H-M-C-G (thermal - hydrological - mechanical - chemical - geometrical) process associated with perturbations at description of potential changes of the geological environment. In this report, we revised the framework as a part of the total system performance assessment for two purposes: the first one is quantification of relationship of characteristic of natural phenomena between geological environmental conditions (THMCG), and the other one is quantification of relationship of THMCG condition between parameters of performance assessment. On the other hand, we applied the revised framework to all natural phenomena. As a result, to apply the revised framework, we could show that information integration could carry out efficiently. In particular, we introduced the view of change of situations about phenomena such as climate changes which the grade of impact cannot grasp easily as compared with volcanism. Thereby, information integration was attained by the common framework. Furthermore, we could show that suitable scenarios might be chosen by information integration. (author)