Influence of β radiation on UO2dissolution at different pH values

Abstract

SummaryIn this work we studied the effect of external β radiation (90Sr-90Y source with an activity of 7 mCi) on the dissolution rate of non-irradiated UO2as a chemical analogue of spent nuclear fuel (SF). The experiments were carried out at three different pH values inside a glove-box in nitrogen atmosphere to avoid oxygen contamination. The MAKSIMA code was used to model the generation of radiolytic products, both molecular species and radicals.The formation of hydrogen peroxide in solution was observed in the experiments, as was predicted by the MAKSIMA code. When H2O2could be quantified, its concentration was within the range predicted by this code. In addition, the application to our data of an empirical model for UO2dissolution in the presence of H2O2gave similar results.The UO2dissolution rates obtained in this work were similar to the UO2corrosion rates determined electrochemically and under γ irradiation with a similar dose rate. On the other hand, they were always lower than the ones obtained with "fresh" spent nuclear fuel, probably because in this case the dose rates to the solution are higher and, in addition, more than just β radiation is emitted by the fuel.