|About this Abstract
||MS&T23: Materials Science & Technology
||Emergent Materials Under Extremes and Decisive In Situ Characterizations
||In Situ Characterization and Modeling of Spent UO2 Fuel under Ion Irradiation
||Lingfeng He, Yunyuan Lu, Cameron Howard, Chao Jiang, Sudipta Biswas, Dewen Yushu, Jatuporn Burns, Wei-Ying Chen
|On-Site Speaker (Planned)
Spent nuclear fuel undergoes significant microstructural and chemical changes during reactor operations. Some fission products remain in solid solution within the UO2 matrix, while inert gases such as xenon (Xe) and krypton (Kr), as well as metals in the 4d group (molybdenum, technetium, ruthenium, rhodium, and palladium), form nanoprecipitates within the UO2 matrix. Kr/Xe precipitates and metallic precipitates can also form a pair structure at the rim regions of the UO2 fuel. Additionally, grain subdivision of UO2 occurs above certain burn-up levels, resulting in the formation of a high burn-up structure (HBS) composed of nanograins. This study characterizes the in situ microstructural evolution of nanoprecipitates and HBS under Kr or Xe ion irradiation in spent UO2 fuel using transmission electron microscopy techniques. Density-functional theory and phase-field modeling are also utilized to better understand the in situ microstructural evolution of nanoprecipitates and grain growth in UO2.