The stabilities of selected fission products are investigated as a function of stoichiometry in uranium oxide. The approach is density functional theory (DFT) that is used to calculate the incorporation and solution energies of solid and gaseous fission products at the anion and cation vacancy sites, at the divacancy, and at the bound Schottky defect. In general, higher charge defects are predicted to be more soluble in the fuel matrix and the solubility of fission products increases as the hyperstoichiometry increases. The solubility of fission product oxides is also explored and the results compared to experimental findings. The clustering of fission products within the uranium oxide lattice provide insight into the formation of metallic inclusions.
In conjunction with Pankaj Nerikar (IBM, India), Minki Hong, James S. Tulenko, Simon R. Phillpot (Department of Materials Science and Engineering, University of Florida), Taku Watanabe (Department of Chemical Engineering, Georgia Tech), Blas P. Uberuaga, Chris Stanek (Los Alamos National Laboratory).
This work was funded by the DOE
ARMS 1010, Purdue University, West Lafayette, IN