Thermal Transport in Actinide Oxides with Interstitial Defects

Abstract

Safe and efficient operation of nuclear reactors require better understanding on thermal transport in fuels used in reactors; accelerated heat dissipation in nuclear fuels is critical to the reduction of fission gas release caused by thermal imbalance in fuels and mechanical damages caused by the thermal expansion of the fuels. In this research, three representative actinide oxides (UO₂, PuO₂, and ThO₂) are chosen to explore the thermal transport in nuclear fuels at microscopic level. Reverse non-equilibrium molecular dynamics (RNEMD) is utilized to estimate the thermal conductivities of UO₂, PuO₂, and ThO₂ at 300K. Several sample lengths and different interstitial defect concentrations of 0.1%, 0.5%, 1%, 2%, and 5% are chosen to better understand the thermal behavior of the nuclear fuels. The results show that any alteration to the lattice structure of these nuclear fuels reduces their thermal properties significantly.