ASSESSMENT OF EMERGENCY PLANNING ZONE FOR SMALL MODULAR PRESSURIZED WATER REACTORS BASED ON THE RISK-INFORMED METHODOLOGY

More than 80 Small Modular Reactors(SMRs) designs are under development worldwide. SMRs usually have the characteristics of integrated design, modular manufacturing and installation, high safety, and proximity to users, and have broad prospects for development and application. Due to the lower power levels and passive safety features of SMRs, the radioactive releases, both in magnitude and frequency, would be significantly lower than that of large reactors. Too large emergency planning zone(EPZ) size may limit the flexible deployment of SMRs. How to reasonably determine the EPZ size of small reactors has become a focus in the nuclear industry. Based on the risk-informed methodology recommended by IAEA-TECDOC-1652, considering both the frequency of the entire spectrum of accident scenarios and the dose consequence for each scenario, this paper analyzes and calculates the EPZ size of a certain small modular pressurized water reactor in China using the Level-2 PSA (Probabilistic Safety Analysis) source terms and the site actual meteorological data. Based on the realistic models, the preliminary recommended EPZ size is about 700m. Even in the conservative meteorological conditions, the EPZ size is about 2.7km, which shows a significant reduction than that of large reactors. The risk-informed methodology is an application of Level-3 PSA supporting in the EPZ sizing. The results could further improve the public's acceptance and recognition of SMRs and promote their safe and reliable deployment worldwide.