Annular fuel behavior analysis of U3Si2 fuel and FeCrAl cladding based on multiphysics field method

Safety, efficiency and economic benefits cannot be ignored in the development of nuclear energy. As a type of widely used fuel in nuclear reactors, solid fuel has limited potential, long investment return cycle of new nuclear reactors and great construction resistance. Addressing these challenges, two effective approaches involve the utilization of new fuel cladding materials, specifically Accident Tolerant Fuel (ATF), and the incorporation of novel fuel pellet structures to improve economic viability and safety. In this paper, an ATF of U₃Si₂-FeCrAl system with annular structure is analyzed based on a fuel behavior analysis code CAMPUS-ANNULAR. The assessment encompasses fuel performance under typical normal operating conditions and accident scenarios such as Loss of Coolant Accident (LOCA) and Reactivity Initiated Accident (RIA). By employing the solid fuel performance analysis code CAMPUS, a comparative work is conducted to evaluate the performance of the solid U₃Si₂-FeCrAl system under both normal and accident conditions. Results indicate that, during normal operation, the annular U₃Si₂-FeCrAl system with equivalent power density reduces peaking fuel temperatures by about 70 K–150 K in comparison to the solid U₃Si₂-FeCrAl system. This reduction enhances the temperature margin under accident conditions, subsequently lowering the risk of fuel meltdown. However, the annular U₃Si₂-FeCrAl system increases the risk of Pellet Cladding Mechanical Interaction (PCMI) failure under RIA condition.