The effects of Xe/Cs occupation on the thermal transport properties of U3Si: A first-principles study

In this study, the effects of fission products (FPs) Xe and Cs on the thermal conductivity for U3Si, which has been proposed to be an alternative nuclear fuel for UO2 due to its high thermal conductivity and high uranium density, are systematically investigated based on first-principles calculations. It is shown that Xe/Cs occupation in U3Si results in thermal conductivity decreasing from 15.6 to 6.5 14.0 W/mK at 300 K and from 31.7 to 12.9 29.6 W/mK at 1000 K. This is mainly resulted from the weakened chemical bonding, decreased phonon group velocity, as well as destroyed periodic structures caused by Xe/Cs occupation.