The inhibiting effects of hydrogen on the corrosion of uranium dioxide under nuclear waste disposal conditions

A number of electrochemical experiments were employed to investigate the effects of hydrogen on the corrosion of UO2 under nuclear waste disposal conditions. A combination of corrosion potential (ECORR) measurements and cyclic voltammetry have indicated that dissolved hydrogen can polarize the UO2 surface to reducing potentials; i.e., to ECORR values more negative then those observed under anoxic (argon-purged) conditions. A comparison of the behaviours of SIMFUEL specimens with and without incorporated noble metal ε-particles indicates that these particles may act as catalytic electrodes for H2 oxidation, H2 ↔ 2e− + 2H+. It is the galvanic coupling of these particles to the UO2 matrix which suppresses the fuel corrosion potential.