Modeling of induction stirring and particle tracking in molten uranium

Abstract Two independent numerical models have been developed to simulate the behavior of carbon impurities in molten uranium metal. Informed by experimental parameters, one model was created using the commercial software Star-CCM+ and compared with another developed using open-source codes, including OpenFOAM, Finite Element Method Magnetics (FEMM) and a First Passage Kinetic Monte Carlo (FPKMC) approach. The target experimental system features a 404 g uranium metal charge containing an average carbon concentration of 139 ppm, 1-2 which was melted in a vacuum induction furnace at 1400° C then resolidified. The microstructures of the uranium and its impurities before and after melting have been characterized and reported separately. 3-4 Prior to simulating the uranium-carbon system described, the numerical models were validated using a previously published nonradioactive experimental system, to ensure agreement with expected output values. 5 Focus has been placed on modeling velocity fields under induction stirring and impurity particle trajectories. the long-time-scale oscillations. It is important to take these long-term oscillations into account, as they dominate the particle movement. 47 Related recent work has also focused on the behavior of the free surface of the melt and the complicated interactions between the EM field, the flow pattern, and the surface shape. 49 Early work used a reciprocal process for calculating the interactions between the EM field and the free surface shape. 50 The free surface oscillation period can be found analytically to depend only on the crucible geometry when the Lorentz force is radial and constant. 51 More advanced results require an iterative approach coupling the EM forces and the hydrodynamic flow. 49, 52 The models reported here employ and integrate previously published computational approaches for application to a specific uranium system.