A First Principles Study of Palladium Impurities in Silicon Carbide

The main task of the silicon carbide layer in Triso-coated fuel particles for gas-cooled high temperature fission reactors is to retain fission products. It has been observed that some fission products, and in particular Pd, attack the SiC layer and are supposed to be responsible for corrosion of the material, which could facilitate fission products release. We used first principles calculations based on Density Functional Theory (DFT) in order to investigate the energetic, structural, and kinetic properties of Pd impurities inside SiC; we obtained solution and migration energies in pure SiC and discuss the thermodynamics of a few reactions that could possibly occur for Pd impurities in silicon carbide.