Accident tolerant fuel thermal hydraulic behaviors evaluation during loss of coolant accident in CPR1000. (May 2020) - Yu, Honghao
Highlights: ATFs during SBLOCA with failure of all SI are analyzed. Un-irradiated and irradiated SiC claddings during LOCA are contrasted. UO2 +BeO pellet will melt before traditional UO2 pellet. For CPR1000 power plant, SI is particularly important during LOCA. FCM-SiC is a good combination of ATF materials in terms of thermal hydraulics. Abstract: Accident tolerant fuel (ATF) is characterized by enhanced thermal and mechanical performance. This paper focuses on two kinds of ATF pellet fuel (UO2 +10%/20%/30%BeO and FCM) and two kinds of ATF claddings (FeCrAl and SiC). Irradiated and unirradiated SiC materials were simulated separately considering the thermal performance degradation after SiC irradiation. A CPR1000 system model loaded ATF is established using RELAP5/MOD3.4 system code, and besides thermal hydraulic characteristics during small break loss of coolant accident (SBLOCA), SBLOCA with all Safe Injection (SI) failure and large break loss of coolant accident (LBLOCA) is investigated. The study results indicate that the temperature of each "ATF pellet-cladding" differs little and is below failure temperature during SBLOCA and LBLOCA. However, during SBLOCA with all SI failure, ATF pellets can reduce MFCT but UO2 +BeO pellet will melt before traditional UO2 pellet. Among them, FCM-SiC is a good combination of ATF materials in terms of thermal hydraulics.