Studies of Liquid-like Lanthanide Transport Behaviors in Metallic Nuclear Fuel

The metallic fuel in fast reactors has shown the phenomenon of fuel cladding chemical interactions (FCCI). Lanthanide fission products can migrate to the fuel periphery and interact with the cladding materials leading to clad failures. In order to mitigate FCCI, a fundamental understanding of the lanthanide transport mechanism is necessary. Post-irradiation examination (PIE) of Experimental Breeder Reactor-II (EBR-II) has led to a "liquid-like" transport mechanism which can qualitatively account for the lanthanide migration and sludge-like deposition on the fuel periphery. In the present thesis, an integrated model of the lanthanide transport behavior in metallic fuels is proposed based on the liquid-like transport mechanism. It includes the pore-scale models of lanthanide transport within a single or multiple pores and a macroscopic description of lanthanide migration in porous media. The integrated model is implemented in MOOSE/BISON and can be used to quantitatively predict the lanthanide migration and redistribution in the metallic fuel.