Incorporating dislocation loop interactions from dislocation dynamics to crystal plasticity model of irradiated UO₂

Accurate assessment of the irradiation-induced hardening of the fuel requires sophisticated multiscale micromechanical modeling framework. This work proposes a method to link dislocation dynamics (DDD) and crystal plasticity (CP) to evaluate the effect of dislocation loops on UO₂ strengthening and localization phenomena. Dislocation dynamics is used to quantify dislocation to dislocation loop interaction with respect to the incident angle of gliding dislocation and prismatic loop habit plane. The change in flow resistance provides the effective interaction coefficient depending on dislocation loop size and dislocation type (edge or screw component). Anisotropic dispersed barrier hardening model is then established based on DDD results, which is used to formulate slip resistance at CP level amplified with anisotropic dislocation loop interactions. We utilize the CP model to investigate changes in yield stress and strain hardening/softening due to the presence of dislocation loops in UO₂. These results give perspective how dislocation loops alter plastic deformation and strengthening in UO₂ for the first time at microstructural scale via CP modeling.