Oxidation of accident tolerant fuels models based on Cr-doped UO2 for the safety of nuclear storage facilities

Abstract

Oxidation of Accident-Tolerant Fuels (ATF) is important from the nuclear safety point of view because it could provoke the release of radioactive material. Despite of the use of ATFs in current nuclear reactors, no studies regarding their oxidation are available. Thus, we propose here an experimental study on Cr2O3-doped UO2 samples, which were subjected to a thermal treatment ranging from room temperature up to 973 K in oxidant conditions. The aim is to assess the potential oxidation resistance of Cr-doped UO2 based model systems. Next, the effect of oxygen partial pressure and the influence of Cr2O3 dopant concentration concentrations on fresh UO2 fuel oxidation were evaluated. Two oxygen compositions (1% and 21%O2) were used to further evaluate the impact of Cr2O3 concentrations on UO2 oxidation. The results show that, despite no effect of the dopant is found in air (21% O2), there is a clear decrease in the oxidation degree at 1%O2. These results are intended to provide a fundamental reference for future investigations of Cr2O3-doped UO2 corrosion behavior and performance to be accounted in new designs of storage facilities.