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 (E-CORR) 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. (C) 2014 Elsevier Ltd. All rights reserved.