A comparison of empirical potential models for the simulation of dislocations in uranium dioxide

The presence of dislocations, resulting from high levels of irradiation, in nuclear fuel may have a profound effect on the fuel's properties. Here atomistic simulations, employing empirical pair potentials, are used to examine the core structures of a series of dislocations in UO2 with Burgers vector 1/2〈110〉 and their relative stabilities are assessed by comparing their line energies. As there are a large number of empirical pair potential models available for UO2 a critical assessment of the efficacy of the potential models is also presented. There is a high level of agreement between the different pair potential models with all those tested predicting the same ordering of the dislocation stabilities i.e. screw < {100}〈110〉 < {111}〈110〉 < {110}〈110〉 which is in excellent agreement with experiment.