The behavior of unirradiated UO 2 and uraninite under repository conditions characterized by Raman

Raman spectroscopy studies have been performed on one hand to identify different materials related to spent nuclear fuel (SNF), and on the other hand to study the behavior of SNF at different storage conditions. Specifically, the expected oxidation of the SNF matrix under dry storage conditions and the formation of secondary phases (SP), as a result of corrosion of SNF in a deep geological repository, have been studied. In order to perform these experiments, two protocols based on the Raman spectroscopy technique have been developed. The results show U 4 O 9 /U 3 O 7 and U 3 O 8 as oxidation products of UO 2 powder at high temperatures in air, and the secondary phase formation (rutherfordine, UO 2 (CO 3 ), soddyite, (UO 2 ) 2 SiO 4 •2H 2 O, uranophane alpha Ca(UO 2 ) 2 (SiO 3 OH) 2 •5H 2 O and kasolite, PbUO 2 SiO 4 •H 2 O), due to uraninite corrosion under the conditions of Sierra Albarrana (Spain).