Molecular dynamics study of mixed oxide fuel

In order to develop new techniques to calculate the physicochemical properties of MOX fuel, molecular dynamics methods were applied to UO2, PUO2, and (U,Pu)O2. These methods enabled us to obtain the heat capacity and thermal conductivity from basic properties, viz., the lattice parameter, linear thermal expansion coefficient, and compressibility. Results for UO2 showed both the existence of a Bredig transition and a peak in the heat capacity at high temperature. The lattice parameter, heat capacity, and thermal conductivity of MOX fuel were calculated from basic properties of UO2 and PuO2. These results showed that molecular dynamics techniques can be usefully applied to determine physicochemical properties of MOX fuel.