Calculations of thermodynamic properties of PuO2 by the first-principles and lattice vibration

Plutonium dioxide (PuO2) is a key compound of mixed oxide fuel (MOX fuel). To predict the thermal properties of PuO2 at high temperature, it is important to understand the properties of MOX fuel. In this study, thermodynamic properties of PuO2 were evaluated by coupling of first-principles and lattice dynamics calculation. Cohesive energy was estimated from first-principles calculations, and the contribution of lattice vibration to total energy was evaluated by phonon calculations. Thermodynamic properties such as volume thermal expansion, bulk modulus and specific heat of PuO2 were investigated up to 1500 K.