ABSTRACT
BGE TECHNOLOGY GmbH (BGE TEC) and Sandia National Laboratories (SNL) developed and jointly tested a methodology for the safety assessment of engineered barrier systems (EBS) for a high-level waste/spent nuclear fuel (HLW/SNF) repository in salt. Long-term isolation in such a repository is provided by a multi-barrier system including natural and engineered barriers. The salt provides the natural barrier, whereas the engineered barriers are different sealing components installed in the repository. The developed methodology is tested via a generic repository concept that is situated in a generic bedded salt formation. Based on this, a global model was generated, including relevant stratigraphic layers and underground openings of the repository. BGE TEC used this model to perform the integrity assessment of the shafts and drift sealings as main parts of the EBS. Simultaneously, SNL conducts the radiological performance assessment (PA). Both parts interact by an optimization of the EBS based on PA simulations and EBS-parameters. For this purpose, sensitivity analyses were incorporated into the PA simulation. This contribution presents the modeling and methodological approach used for BGE TEC and SNL for the design and performance assessment of EBS.
