Electrochemical and Surface Characterization of Uranium Dioxide Containing Rare-Earth Oxide (Y2O3) and Metal (Pd) Particles

Four specimens of uranium dioxide doped with rare-earth oxide (Y2O3) and/or metal particles (Pd) i.e., UO2, UO2-Y2O3, UO2-Y2O3-Pd, UO2-Pd were surface and electrochemically characterized using scanning electron microscopy (SEM/EDX), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry. Surface analyses showed that the dopants are present as a separate phase in the UO2 matrix and all oxides are non-stoichiometric and contain a large number of defect clusters. Voltammetry shows anodic oxidation begins at sub-thermodynamic potentials and the presence of multiple cathodic reduction peaks indicates the presence of a number of structural domains with different electrochemical reactivities. Corrosion potential (ECORR) and polarization resistance measurements (Rp) in the presence of H2O2 suggests that the anodic reactivity of all the specimens is comparable and high compared to 1.5 at% SIMFUEL. The lower Rp values obtained on the doped specimens is consistent with the presence of readily oxidizable cuboctahedral clusters in the oxide matrix