A New Safety Concept for Geological Disposal in Japan (II)

This paper provides further discussion of a new defence-in-depth safety concept that was presented at ICEM09[1]. The basic idea is that it is rational to assume that the performance of passive engineered barriers with suitably chosen characteristics and the natural barrier will maintain their safety functions for a sufficiently long time due to geochemical buffering occurring deep underground, The approach can be used to enhance and embed public understanding of the long-term safety of geological disposal. This paper summarizes the logic of the approach focusing on the following topics, which are the basic themes of the new safety concept. 1. Applicability of the defence-in-depth concept to the geological disposal of radioactive waste; 2. Natural Analogue approach to explaining the long-term behaviour of the barriers; and 3. Approach for the Social Dialogue with stakeholder, which is the most important issue for site selection.