Calculation of the effective thermal conductivity of porous polycrystalline U-10Mo alloy based on phase-field simulation

Abstract

In the present work, the thermal conductivity of U-10Mo was calculated, considering the effects of different microstructures, including fission bubbles and recrystallization, through simulations using the phase-field method. The concept of effective thermal conductivity was used to describe thermal conductivity. Systematic calculation was conducted to determine the effect of fission bubble porosity on thermal conductivity. A shape factor was proposed to quantitatively represent the different shapes of bubbles, and the specific expression was also given. It was found that the shape factor had a significant impact on thermal conductivity. Additionally, the effects of grain refinement and coupled bubble evolution with different fission densities on thermal conductivity had been quantitatively studied. The calculated results were in good agreement with the experimental results. It was revealed that recrystallization had a significant impact on thermal conductivity, with higher irradiation density resulting in lower thermal conductivity due to the higher GB density and larger porosity. Based on the models presented in this paper, it is of great engineering significance to predict the thermal conductivity changes of U-10Mo fuel in service.