Several electrochemical behaviors at UO2 and SIMFUEL electrodes were investigated and compared in NaCl and carbonate solutions at several pH values of from acidic to alkaline conditions with measuring cyclic voltammograms in a wide potential window with a positive limit of up to 4 V to understand the more general anodic dissolution characteristics of UO2 oxide. The voltammogram behaviors were much changed according to the solution condition and the electrode. The voltammogram change, dissolution mechanism of electrodes, formation of corrosion products at the electrode surface, and equilibrium corrosion potentials were explained and evaluated. The corrosion product generated at the electrode surface distorted the cyclic voltammogram over the potential region of oxygen evolution and increased the overpotential of oxygen evolution at the electrode, and affected greatly the repeatability of the consecutive cyclic voltammograms. The corrosion product to hinder and block the electrode surfaces changed from UO2CO3 to UO2HCO3, as the carbonate solution pH changed from higher region to lower region. There was no effect of the corrosion product on the voltammograms in NaCl solutions with acidic and alkaline pHs at both electrodes. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.046201jes] All rights reserved.