LAUSR

Abstract This paper describes use of sub-channel analysis code COBRA-EN to assess the thermal hydraulic performance and influence of different coolant channel geometries on several accident tolerant fuel (ATF) materials. The results show that FeCrAl-based alloy (AMPT) cladding could reduce peak cladding temperature (PCT) and peak fuel centerline temperature (PFCT), but irradiated SiC/SiC composite (SA3/PyC50-A) cladding raised them. Significant PFCT reduction could be achieved by using ATF fuels, but higher PCT with heat transfer deterioration. In order to analyze the potential impact of coolant channel geometry size, four geometry models were subjected to sensitivity analysis. The results show that previous coolant channel geometry size was the best design for UO2. Heat transfer deterioration on cladding surface of ATF fuel/cladding systems could be sufficiently improved with 10% increase of coolant channel geometry size. So, 10% increase of coolant channel geometry size for ATF fuel/cladding systems possible is a better design.