Molecular dynamics study of mixed oxide fuel

Evaluation of thermal and transport properties of actinide mixed oxide fuels is the problem of a high importance for development of new generation reactors. Molecular dynamics (MD) provides a powerful tool, that can be used for this goal. This article presents the results of the MD modelling of UO2, PuO2 and (Pu0.3U0.7)O2 oxide nuclear fuels with purpose to evaluate their thermal and diffusion properties. Specific heat, thermal conductivity and thermal expansion of these materials were estimated in the temperature range of 300-2500 K and compared with available recommendations. Migration energies of the anion and cation diffusion via the interstitial and vacancy mechanisms have been calculated together with self-diffusion coefficients. The presence of a strong interaction between point defects and Pu atoms has been revealed in the case of (Pu0.3U0.7)O2. (author)