Comparative analysis of auxiliary feedwater system and passive safety system under typical accident scenarios for integrated pressurized water reactor (IPWR)

The Integrated Pressurized Water Reactor (IPWR) designed with series of passive safety system has been regarded as a very promising reactor concept. In this paper, in order to assess the accident mitigation ability of passive safety systems in China 100 MW IPWR, the complete system models, including the reactor vessel, passive safety injection system and passive residual heat removal system, were established using RELAP5 software. The comprehensive and quantitative comparative analysis of auxiliary feed water system and passive safety system under typical accident scenarios, including loss of flow accident and Station Black-out (SBO), were investigated, respectively. Results show that the passive residual heat removal system has the similar accident mitigation capability compared with the auxiliary feed water system, which is adopted in most of traditional PWR design. And the IPWR could realize the reactor safe shutdown under typical accident scenarios with passive safety systems. Finally, the Small break loss of coolant accident (SBLOCA) induced by pressurizer surge line rupture was calculated to verify the function of passive safety systems for IPWR. Results demonstrate that the passive safety system could provide emergency coolant to the reactor and remove the reactor decay heat successfully. This work is meaningful for the quantitative evaluation of passive safety systems in IPWR.