Validating an Atomic Interaction Model of Zirconium for Collision Cascade Simulations

Abstract

Zirconium alloys are widely used by the nuclear industry. For this reason, there is a rich literature describing the study of neutron radiation-induced damage in Zr. In particular, molecular dynamics (MD) is routinely used to predict primary damage production. In order to perform MD simulations, the modeller must provide an underlying model for interatomic interactions. One such model is the Embedded atom method (EAM). In particular, two Zr EAM models proposed by M.I. Mendelev and G.J. Ackland (M2 and M3 potentials) serve as the basis for the bulk of recent MD simulations of primary damage production in Zr found in the literature. Here, M2/M3 predictions and the electronic density functional theory (DFT) calculations were compared using embedded dimer and equation of state analyses. Simulation of systems in which atoms are subjected to very high repulsive force at short interatomic distances-i.e. conditions representative of those observed during primary damage production- proves that M2/M3 are in need of modification. Consequently, through a series of effective gauge transformation, saturation, splines and minimizations, a modified potential is developed which successfully predicts interatomic forces at close distances.