Abstract: In accordance with the requirements of IAEA Safety Guide SSG-23, a safety case study for the Southwest radioactive waste disposal facility was conducted from 2019 to 2023. This research has developed a site-specific FEPs (Features, Events, and Processes) list and assessment scenarios for the facility, projected future climate change prediction in the facility site region, established a concrete evolution model for the disposal units and a long-term dynamic model of groundwater level. Migration parameters are also provided for representative radionuclides in both concrete and undisturbed soil. This research achievement could serve as a demenstration for China to develop guidelines for safety process system analysis, and provide reference for other near surface disposal facilities to conduct safety process system analysis research.

Key words: near surface disposal, safety evaluation, safety case study