|About this Abstract
||2022 TMS Annual Meeting & Exhibition
||Advanced Characterization and Modeling of Nuclear Fuels: Microstructure, Thermo-physical Properties
||Experimentally Validated Model for Investigating High-burnup Structure Formation in U-Mo Fuels
||Sudipta Biswas, Charlyne Smith, Brandon D. Miller, Dennis D. Keiser , Assel Aitkaliyeva
|On-Site Speaker (Planned)
High-burnup regions in irradiated fuels exhibit a fine-grained microstructure with large pores, known as a “high-burnup structure.” In this study, we utilize a grand-potential-based phase-field modeling approach to investigate the mechanisms behind such structure formation in U-Mo fuels. It is hypothesized that irradiation-induced damage of existing grains leads to the reorganization of dislocations into low-angle grain boundaries (LAGBs), creating subgrains within the existing damaged grains. Over time, these subgrains lead to the formation of new grains with high-angle grain boundaries (HAGBs). The model employs a fission-density-based discrete nucleation algorithm to simulate the recrystallization process. It is observed that the first LAGB-to-HAGB transition occurs at a fission density of 2.3×1021 fissions/cm3. With increasing fission density, the fraction of damaged residual grains with LAGB subgrains decreases. Additionally, the presence of fission gas pores accelerates the HAGB grain nucleation. The model prediction is validated against the experimental characterization, using electron microscopy techniques.
||Computational Materials Science & Engineering, Nuclear Materials, Modeling and Simulation