Developing resilient concepts for geological disposal of waste in Japan - 5289

Since the Great Tohoku earthquake, tsunami and reactor meltdowns, there has been increased public concern regarding nuclear issues and also on the potential of major natural hazards to cause accidents at nuclear facilities. In response to this - and to help rebuild the public confidence required to site a repository - a study has examined if the concept of resilience, as commonly applied in the nuclear power industry, could be applied to a geological repository. This is an expansion from past work which tended to focus on defence in depth during construction and operation, while the robustness provided by the multiple barrier concept is the basis of passive safety for the post-closure phase. Resilience in this context means not only assuring safety during expected conditions, but also resistant to perturbations, including human factors, mitigating their consequences and easing recovery. This paper summarises output from such considerations, with a special focus on the recent assessment of repository life-cycle for a range of repository concepts, for some of which temperature management is a concern during the operational phase. Interestingly, this led to highlighting some operational concerns that could be managed by engineering measures, leading to a novel 'resilient' repository design. (authors)