Thermal Conductivity of UO₂, ThO₂ and U-ThO₂

Nuclear fuel thermal conductivity directly impacts reactor safety and efficiency. This presentation summarizes our recent research on thermal transport behavior of actinide materials ThO2, UO2, and U-ThO2 in pristine and irradiated states. Through a fundamental analysis of phonon scattering mechanisms, especially with the 5f electron related electron spins and various microstructural defects, we investigate the defect generation and evolution within fuels throughout their service life, and the corresponding influences on their thermal conductivity. These insights will contribute to the advancement of fuel performance codes and pave the way for the development of high thermal conductivity fuels.