Gd<sub>2</sub>O<sub>3</sub> Doped UO<sub>2</sub>(s) Corrosion in the Presence of Silicate and Calcium under Alkaline Conditions
Sonia García-Gómez,
Javier Giménez,
Ignasi Casas,
Jordi Llorca,
Joan De Pablo
Affiliations
Sonia García-Gómez
Department of Chemical Engineering, EEBE and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC), Eduard Maristany, 10-14, 08019 Barcelona, Spain
Javier Giménez
Department of Chemical Engineering, EEBE and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC), Eduard Maristany, 10-14, 08019 Barcelona, Spain
Ignasi Casas
Department of Chemical Engineering, EEBE and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC), Eduard Maristany, 10-14, 08019 Barcelona, Spain
Jordi Llorca
Department of Chemical Engineering, EEBE and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC), Eduard Maristany, 10-14, 08019 Barcelona, Spain
Joan De Pablo
Department of Chemical Engineering, EEBE and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC), Eduard Maristany, 10-14, 08019 Barcelona, Spain
The anodic reactivity of UO2 and UO2 doped with Gd2O3 was investigated by electrochemical methods in slightly alkaline conditions in the presence of silicate and calcium. At the end of the experiments, the electrodes were analysed by X-ray photoelectron spectroscopy to determine the oxidation state of the uranium on the surface. The experiments showed that the increase in gadolinia doping level led to a reduction in the reactivity of UO2, this effect being more marked at the highest doping level studied (10 wt.% Gd2O3). This behaviour could be attributed to the formation of dopant-vacancy clusters (GdIII-Ov), which could limit the accommodation of excess O2− into the UO2 lattice. In addition, the presence of Ca2+ and SiO32− decreased the anodic dissolution of UO2. In summary, the Gd2O3 doping in presence of silicate and calcium was found to strongly decrease the oxidative dissolution of UO2, which is a beneficial situation regarding the long-term management of spent nuclear fuel in a repository.
