LONG-TERM SAFETY ANALYSIS AND MODEL VALIDATION THROUGH URL RESEARCH-A MAJOR TASK OF GRS' FINAL REPOSITORY RESEARCH DIVISION

摘要

In Germany all types of radioactive waste will be disposed of in deep geological repositories. While a repository for low-level radioactive waste (LLW) has recently been licensed, different host rock formations are considered for disposal of heat producing high-level waste (HLW). The latter includes directly disposed spent fuel and vitrified waste from its reprocessing. Different canister and disposal concepts are considered for spent fuel disposal, i.e. thick-walled iron casks in horizontal drifts or thinwalled BSK3 steel casks in vertical boreholes, respectively. GRS is the leading expert institution in Germany concerning nuclear safety and waste management Since 30 years, GRS has developed and continuously improves a set of computer codes, which allow to assess the performance and the long-terM safety of repositories in various host rocks (salt, clay or granite) applying different technical options. Advanced methods for deterministic as well as probabilistic assessments are available. In order to characterize the host rocks and backfill/buffer materials and to develop disposal technologies, comprehensive laboratory experiments and a large number of in-situ tests have been performed at GRS' geo-laboratory and at underground research laboratories in different host formations. THMc processes occurring in the host rocks and engineeredbarrier-systems are numerically simulated. The paper presents an overview of GRS' work highlighting important results of PA studies for both the salt option and the clay option. Also, recent results of in-situ investigations and laboratory studies will be presented together with modeling results. Special emphasis is dedicated to the consideration of coupled tHM processes which are of relevance in PA.