Enhanced radiation damage tolerance in Zr-doped UO2

Abstract

This study explores the effect of tetravalent Zr doping on the radiation behaviour of UO₂ through a combination of experimental and theoretical approaches. The intrinsic changes that Zr introduces in UO₂ were quantified using X-ray diffraction and Raman spectroscopy, which reveal a shrinkage of the lattice volume and the formation of ZrO₈-type clusters. Heavy-ion irradiation was carried out on both undoped and doped UO₂ under conditions similar to the ballistic regime of fission products in nuclear fuels. Empirical data, together with DTF+U simulations, found that Zr doping modifies the irradiation-induced defect mechanisms by enabling recombination pathways, allowing a rapid recovery of the UO₂ lattice. The fundamental mechanisms involving the role of dopant in modifying the radiation damage kinetics are discussed in this paper, as well as the subsequent evolution in fluorite-structured materials relevant to nuclear fuels.