| Abstract Scope |
The growing interest in molten salt reactors (MSRs) as next-generation nuclear energy systems necessitates a comprehensive understanding of material degradation under simultaneous exposure to corrosive environments and radiation. This study investigates the coupled effects of irradiation and corrosion on stainless steel in contact with molten salt FLiNaK at 973 K. Leveraging the Phase Field Method, a computational model was developed to capture the interplay between microstructural evolution and elemental diffusion under irradiation-induced defects. The model incorporates key parameters, including vacancy concentrations, grain boundary effects, and radiation-induced damage, to simulate chromium depletion and intergranular attack at GBs. The simulated results reveal that irradiation intensifies grain boundary depletion of chromium, accelerating localized corrosion mechanisms. However, under non-irradiated conditions, corrosion progresses uniformly, with less pronounced microstructural features.
Key findings include the identification of high vacancy concentrations at grain boundaries as a critical driver for enhanced diffusivity and selective leaching of chromium into the molten salt. Additionally, simulations indicate a threshold radiation flux beyond which defect production rates significantly alter corrosion kinetics. The results have profound implications for the selection and engineering of structural alloys for MSR applications, contributing to improved material performance in extreme environments. |