Atomic scale computer simulation was used to develop models that describe the behaviour of Ru in the dioxide lattice. Results were consistent with observed metal particle formation in UO2-x and UO2. Conversely it was predicted that Ru could be soluble in UO2+x although in irradiated fuel the extent of Ru solution would depend upon the total concentration of fission products as compared to the O interstitial ion concentration. Second-phase oxide particles such as BaRuO3 and RuO2 were not predicted to be stable. At all stoichiometries, the activation energies for migration were high.

The Solution and Diffusion of Ruthenium in UO2±x. G.Busker, R.W.Grimes, M.R.Bradford: Journal of Nuclear Materials, 2003, 312[2-3], 156-62