Study of initial events and safety criteria for CO2 cooled reactor

[Background]As a new concept reactor,direct circulation CO2 cooled reactor has different system configurations and safety characteristics compared with direct cycle boiling water reactor,indirect cycle helium gas cooled reactor and pressurized water cooled reactor,hence the CO2 cooled reactor has different initial events and safety criteria.The selection of initial events is the foundation for the safety design of reactor whilst the safety criteria provides criterion for whether the safety analysis results meet the safety requirements.[Purpose]This study aims at the initial events and acceptance criteria for the safety design of CO2 cooled reactor.[Method]The main logic diagram analysis method was employed to study the initial events of the direct circulation CO2 cooled reactor.Based on the existing engineering experience of pressurized water reactor,gas cooled reactor,the acceptance criteria for the direct circulation CO2 cooled reactor were proposed according to its own characteristics.[Results&Conclusions]The proposed initial events and acceptance criteria required for safety analysis are applicable to direct circulation reactor,providing a basis for the safety analysis of CO2 cooled nuclear power plant,and gives an important reference for the safety design of direct cycle circulation reactors.