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

摘要

U3Si2 fuel and FeCrAl cladding have been reported as candidates of ATF materials. Efforts have been made to study the fuel performance of the U3Si2-FeCrAl system under normal operating conditions, and its fuel perfor-mance is also investigated under accident conditions. In this work, the fuel performance of U3Si2-FeCrAl system is investigated and compared to those of U3Si2-Zircaloy, UO2-FeCrAl, and UO2-Zircaloy systems under LOCA and RIA conditions. And a series of simulations of temperature evolutions with different heat flux are conducted to explore the effect of the heat flux on the temperature. Additionally, sensitivity of the fuel input parameters is analyzed to reveal the main impact on the fuel performance under LOCA condition. Due to the higher thermal diffusivity and lower capacity of the U3Si2 fuel under LOCA condition, the performance of U3Si2 fuel is found to be inferior to UO2 fuel with the same cladding, and the heat flux of cladding outer surface is found to influence the temperature correlations between different fuels. Furthermore, the study of U3Si2 fuel and FeCrAl cladding under RIA condition is also conducted due to their low melting point, and the U3Si2 fuel is found to exceed their melting point in an early time under RIA condition.

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