The influence of rare-earth doping and noble metal inclusions (ε-particles) on H2O2 and O2 reduction and H2 oxidation on UO2 surfaces has been studied electrochemically. These reactions are important in determining the corrosion behaviour of nuclear fuel inside failed waste containers under permanent waste disposal conditions. Experiments were conducted on SIMFUEL electrodes doped with various amounts of non-radioactive elements in proportions appropriate to simulate the chemical effects of in-reactor irradiation. The results show that ε-particles catalyze all of these reactions. These results indicate that ε-particles can act as catalytic anodes and cathodes depending on the redox conditions prevailing within a failed container.