Simulation of collision cascades and thermal spikes in ceramics

Abstract

Classical molecular dynamics simulations have been employed to examine defect production by energetic recoils in UO 2, Gd 2Ti 2O 7, Gd 2Zr 2O 7 and ZrSiO 4. These atomistic simulations provide details of the nature and size distribution of defect clusters produced in collision cascades. The accommodation of recoil damage by lower energy cation exchange and greater occupation of anion structural vacancies is a contributing factor for the greater radiation tolerance of Gd 2Zr 2O 7 relative to Gd 2Ti 2O 7. In addition, electronic energy loss processes in UO 2 has been modeled in the form of a thermal spike to study the details of track formation and track structure. For thermal spikes with energy deposition of 4 keV/nm in UO 2, a track was not formed and mainly isolated Frenkel pairs were produced.