MULTI-SPECIES MULTI-PHYSICS MODELING AND VALIDATION OF HYDRODYNAMIC ELECTROCHEMICAL SYSTEM FOR USED NUCLEAR FUEL

Department of Nuclear EngineeringAccurate predictions of processes in hydrodynamic electrochemical systems require an understanding of both the surface electrochemical reactions and the bulk mass transport. Complete coupling of electrochemistry and fluid mechanics is computationally very rich for multidimensional modeling since it involves multiple components across multi-phases at the same time. Therefore, this study develops a computational model that combines a 3D model for calculating single-species mass transport and a 2D model for calculating multi-species electrochemical reactions. The computational model is validated against lab-scale experimental data using a rotating cylinder solid metal cathode and liquid metal anode in the Argonne National Laboratory. The 3D model assumes that U, the representative component in the system, dominates the hydrodynamic behavior, and thus calculates mass transport caused by the rotating solid cylinder electrode. The 2D model still reflects the diffusion of U, Pu, and Nd within a diffusion boundary layer and the bulk concentration changes of these components. The 3D model provides a diffusion layer thickness reflecting convective mass transfer effects to the 2D model. The results of the proposed model show good agreement with the reference experiment, and the model can be considered an important tool for investigating the multidimensional distributions of hydrodynamic and electrochemical variables.clos