Atomistically-informed modeling of point defect clustering and evolution in irradiated ThO2

A cluster dynamics (CD) model has been developed to investigate the nucleation and growth of point defect clusters, i.e., interstitial prismatic loops nanoscale sub-nanoscale voids, in ThO2 during irradiation by energetic particles. The considers off-stoichiometry due asymmetry generation on O Th sublattices under irradiation, as well diffusivities binding energies clusters. were established using detailed molecular simulations considering statistical variability configuration. high-order adaptive time-integration used solve model. predicted loop density their average size is good agreement with reported experimental observations for proton irradiated at 600°C. did not predict void evolution sluggish kinetics cation vacancies, explaining absence voids (and other oxides) relatively low temperatures.