Effort toward Confidence Building in Total System Performance Assessment for a Potential HLW Disposal in Korea

摘要

Since 1997, KAERI has been devoted to developing needed technologies to ensure long-termrnpost closure safety of a potential permanent repository for HLW. KAERI initiated a study onrnbuilding a KAERI list for features, events, and processes followed by their screening processesrnand constructing feasible scenarios. For each selected scenario, KAERI sets up an appropriaternapproach for total system performance assessment(TSPA). Based on it, KAERI develops a longrnterm plan on software development to secure all computational tools. One of the prime tasksrnidentified in this process is to develop an one-dimensional probabilistic safety assessment code,rnMASCOT-K. The MASCOT was originally developed for LILW disposal, so release features ofrnHLW are added on it. To estimate characteristics of a fractured medium, some multidimensionalrnanalyses on radionuclide migration from a failed container to a fracture surroundedrnby a porous media through a buffer region is considered. Results show that predictions from thernMASCOT-K analysis match well with these independent models. The next step is to securerninput data for TSPA. From literature surveys and pre-run LILW researches, KAERI collectsrninformation adequate for a generic study. Also KAERI has launched key laboratory scale andrnlimited field experiments such as drilling several deep boreholes into crystalline rocks in twornlocations. These data have been logged into the database system, PAID, which is availablernthroughout the internet. Combining these efforts, KAERI is performing the preliminary PSA torncheck whether the Korean reference disposal concept proposed by KAERI can meet regulatoryrnguidelines given by the national authority. Interim results show that even for severe wellrnscenarios, the Korean disposal concept can satisfy the guidelines. A more detailed study is underrnway.