Studies on chemical state of uranium in modified sodium borosilicate glass using X-ray photoelectron spectroscopy and X-ray absorption spectroscopy

The modified sodium borosilicate glass was synthesized by incorporating CaO, TiO2 and Al2O3 to the primary glass forming constituents (SiO2, B2O3 and Na2O) and on melting the mixture at 1373-1473K/3h by melt quench method. Uranium loaded analogues were synthesized by adding varying amounts of UO3 (2,4,6 and 8 mol %) to the borosilicate glass forming reagents then on melting at 1373-1473K. The U-loaded matrices were characterized by XRD to ensure the formation of glass matrices. Solubility of uranium in sodium borosilicate glass has been investigated. Further, the glasses were characterized by X-ray photoelectron spectroscopy (XPS) to unravel the oxidation states of uranium in the modified glass composition. X-ray absorption spectroscopy (EXAFS) revealed the chemical environment of uranium in the glass matrix indicating the coordination number of U in glass.