Assessment of empirical potential for MOX nuclear fuels and thermomechanical properties

We assess five empirical interatomic potentials in the approximation of rigid ions and pair interactions for the (U$_1−y$,Pu$_y$)O solid solution. The assessment compares available experimental data and Fink's recommendation with simulations on: the structural, thermodynamics, and mechanical properties over the full range of plutonium composition, from pure UO$_2$ to pure PuO$_2$ and for temperatures ranging from 300 K to the melting point. The best results are obtained by potentials referred as Cooper and Potashnikov potentials. The first one reproduces more accurately recommendations for the thermodynamics and mechanical properties exhibiting ductile-like behaviour during crack propagation, while the second one gives brittle behaviour at low temperature.