Study on Performance Assessment for HLW Repository in China

This paper presents the latest achievements of performance assessment (PA) for high level radioactive waste (HLW) repository in China. The first PA model, taking Beishan granite site as an example, is established with GoldSim and is verified by comparison with Japanese PA model. Then the behaviors of granite repository in Beishan area are simulated. The results from these simulations show that the engineered barrier is the most important part inside the repository, especially its bentonite plays a key role in the retardation of repository after the nuclide is released from the vitrified waste. Five sensitive parameters are identified and two design parameters are optimized. As a result, it has been proved that performance assessment model is a necessary tool to understand the behaviors of repository, to identify sensitive parameters, and to optimize design parameters.