Computational model of alpha-decay damage accumulation in zircon

Atomic-scale computer simulations are used to study defect accumulation and amorphization due to alpha decay in zircon (ZrSiO4). The displacement cascades, which represent 234U recoil nuclei from alpha decay of 238Pu in zircon, are generated using a crystalline binary collision model. The stochastic production of defects in the crystal lattice, recombination of defects, and the identification of amorphous regions are followed within the framework of a kinetic Monte Carlo simulation. Within the model, amorphous regions are identified as those having a critical density of Zr vacancies. The simulation predicts the interstitial content and amorphous fraction as functions of dose that are consistent with experimental data at 300 K for 238Pu-doped zircon, which indicates that the simulation model for behavior in zircon at 300 K is reasonable.