Microstructural investigations of ion (Kr) irradiated UO2

A single crystal thin film of UO2 on a YSZ substrate was irradiated with 1MeV Kr ions at doses ranging from 1x1014 ions/cm2 to 1x1016 ions/cm2 and temperatures ranging from room temperature to 1000°C. These irradiations were conducted ex situ with one in situ irradiation at 800°C. Post irradiation examination was conducted using transmission electron microcopy to study and characterize the defect evolution in the microstructure. Results show defect nucleation with little growth at room temperature irradiations. As the temperature increases, defects nucleate and grow into dislocation loops and extended networks with increasing dose. At 600°C some dislocation loops form at high dose, but most of the defects remain small and isolated. The in situ 800°C experiment shows the most dislocation loop nucleation and growth. At 1000°C the defects grow at a much quicker rate than at lower temperatures, but anneal out as the dose and irradiation time increases. To summarize, the defect nucleation and growth is linked to the irradiation temperature. At lower temperatures, defects grow into a larger network of defects while at higher temperatures; the damage begins to heal through annealing