ROLES OF THE NUMO SAFETY CASE IN THE STEPWISE SITING PROCESS

摘要

NUMO’s recently completed safety case is genericand will be utilised to support preparation for futurephases of work and development of a template for later,more complete and rigorous, safety cases. This paper putsthe safety case in context by consideration of the stepwiseprocess that will lead to selection of a site for Japan’sfirst deep geological repository. In the staged sitingprocess specified by the Final Disposal Act, the first step,involving site-specific Literature Survey, is initiated whenvolunteer communities come forward. Using the currentsafety case as a template, specific site descriptive models(SDMs) will be developed using planned extension ofcurrent technology to capture both geological history andfuture evolution. The SDM forms the basis ofidentification of potential repository horizons, for each ofwhich illustrative disposal concepts and layouts for HLWand/or TRU waste will be developed to allow their prosand cons to be assessed in terms of both operational andpost closure safety and determine the fundamentalacceptability of the site. This background also serves tofocus the subsequent field investigation programme fromthe surface, in the second Preliminary Investigation step,with further modification and confirmation by DetailedInvestigation to support the licensing process.