Effects of MnO-Al2O3 on the Grain Growth and High-Temperature Deformation Strain of UO2 Fuel Pellets

The fabrication and high-temperature deformation strain of MnO-Al2O3-doped UO2 pelletswere studied. The effects of additive composition and amount on the microstructure evolution of a UO2 pellet were investigated. The compressive creep behaviors of MnO-Al2O3-doped UO2 pellets were examined. The results indicated that a MnO-Al2O3 binary additive can effectively promote the grain growth of UO2 pellets. In addition, the high-temperature deformation strain of the UO2 pellet can be improved significantly with 1,000 ppm 95MnO-5Al2O3 (mol%). The developed MnO-Al2O3-additive-containing UO2 pellets can be a potential candidate for a high-burn-up fuel and a pellet-cladding interaction (PCI)remedy.