Oxygen potential calculations for conventional and Cr-doped UO2 fuels based on solid solution thermodynamics

The effect of Cr-doping on the oxygen potential of UO2 fuels was studied through a comprehensive thermodynamic treatment. Berman-type sublattice solid solutions were formulated and calibrated for UO2 (with Pu, Am, Cm, Np, La, Nd, Ce and Cr as solutes) and for a five-component noble-metal phase (Mo, Pd, Ru, Rh, Tc). Ideal gas, a binary (Sr,Ba)ZrO3 ideal solid solution and a number of stoichiometric solids were also included. The equilibrium calculations were carried out using the GEM-Selektor code with the in-house Heracles database.