b'Thermochemical modelingCoupled thermal-hydraulics and thermochemistry models enable of flow accelerated corrosionsimulation-driven corrosion mitigation solutions for molten salt reactors.in molten salt reactors C orrosion plays a crucial role in molten salt reactors in determining both the structural integrity of reactor components and the thermophysical properties of the fuel salt. Material and barrier degradation and the mechanistic source term of molten salt reactors are affected by corrosion, which is vital for their licensing basis. The ability to employ validated computational simulations for the prediction and mitigation of corrosion in molten salt reactors is essential for licensing, design, and operation. However, before the start of PROJECT NUMBER:this project, no mechanistic model could accurately predict corrosion in molten 22P1068-009FP salts. Hence, the outcome of this project was a coupled thermal-hydraulics and TOTAL APPROVED AMOUNT:thermochemistry model that can accurately predict corrosion phenomena in molten $124,540 over 1 year salts. The newly developed corrosion model, based on INLs MOOSE finite volume method, couples the Navier-Stokes and energy conservation equations with a PRINCIPAL INVESTIGATOR:Poisson-Nernst-Planck model for species transport driven by electrical potential. Mauricio Tano Retamales A detailed treatment of near-wall thermal-hydraulics was added to MOOSE to CO-INVESTIGATORS: better resolve the flow velocity, temperature, and species concentration near the Abdalla Abou-Jaoude, INL walls. Numerical verification of the thermal-hydraulics and Poisson-Nernst-Planck Samuel Walker, INL solutions was implemented to ensure appropriate numerical convergence of the Albert Patrick, Purdue University model. The coupled model was validated for fluoride-based molten salts using Fadel Nasr, North Carolina State University corrosion loop data, demonstrating an agreement in predicting species-dependent corrosion rates within 5%. The model was then applied to predict corrosion rates for the example case of the Molten Salt Fast Reactor. It was shown that corrosion rates are negligible with fresh fuel salt. However, substantial corrosion rates are expected once the fuel salt achieves significant burnup if no corrosion mitigation strategies are implemented. This new modeling capability will continue to mature under the DOEs Nuclear Energy Advanced Modeling and Simulation program until a more substantial validation basis supports its widespread adoption by industry and regulators.58'