Abstract: After the Fukushima accident, IAEA made operational intervention levels as part of its nuclear and radiation emergencystrategy, and required NPPs to set them in advance. The time steps and scope ofprotection actions of IAEA and several major nuclear states are described, as well as their respective protective action criteria, such as operational intervention levels, derived response levels and reference emergency levels. The time dependent curves of OIL1 and OIL2 for 10 accident source terms in five PWRNPPs of China were obtained by using the IAEA-EPR-NPP-OIL operational intervention level calculation formulas. At the same time, the influence of core storage amount on operational intervention level was analyzed. It is expected to provide reference for setting default values for operation intervention levels.

Key words: Nuclear emergency, Operational intervention level, Criterion for protective actions