PRELIMINARY NEUTRONIC/THERMAL-HYDRAULIC AND SAFETY ASSESSMENT OF PRESSURIZED WATER REACTOR LOADED WITH FULLY CERAMIC MICROENCAPSULATED FUEL

As one of the accident tolerant fuels (ATFs), fully ceramic microencapsulated (FCM) fuel shows superior safety performance in accidents, which has the characteristics of high melting point, excellent heat transfer ability and strong nuclear proliferation resistance. Based on the neutronic analysis of Chinese advanced three loop pressurized water reactor (PWR), the assemblies and cores of FCM-SiC and UO2-Zr were designed, power distributions and cycle lengths were obtained, and the power was adjusted to ensure the annual refueling requirements. By using system analysis code, station blackout (SBO) accident in FCM-SiC and UO2-Zr was analyzed, where the steam-driven auxiliary feedwater (AFW) in secondary loop failed to be supplied in time. Assuming that the AFW system couldn't be put into operation immediately after accident, the critical time could be calculated, that is to say, fuel centerline temperature (FCT) and peak cladding temperature (PCT) wouldn't exceed corresponding limits during accident once the AFW was provided within the critical time. It is found that the critical time of FCM-SiC is 9000s and higher than that of UO2-Zr (7000s), which shows the advantages of ATFs. This work could provide reference for the optimized design of the reactor safety system in the future.