Thermal transport properties of uranium dioxide by molecular dynamics simulations

The thermal conductivities of single crystal and polycrystalline UO2 are calculated using molecular dynamics simulations, with interatomic interactions described by two different potential models. For single crystals, the calculated thermal conductivities are found to be strongly dependent on the size of the simulation cell. However, a scaling analysis shows that the two models predict essentially identical values for the thermal conductivity for infinite system sizes. By contrast, simulations with the two potentials for identical fine polycrystalline structures yield estimated thermal conductivities that differ by a factor of two. We analyze the origin of this difference.