Microcrystalline CeO2, ThO2, and UO2 were irradiated with 198 MeV 132Xe ions to the same fluence at temperatures ranging from 25 C to 700 C then characterized by synchrotron X-ray diffraction and X-ray absorption spectroscopy. All samples retain crystallinity and their nominal fluorite-type phase at a fluence of 1.5 1013 ions/cm2 . Both CeO2 and ThO2 display defect-induced ...