Studies on chemical state of uranium in modified sodium borosilicate glass using X-ray photoelectron spectroscopy and X-ray absorption spectroscopy. (January 2021)

• Record Type: Journal Article
• Authors: Praveena, N.; Jena, Hrudananda; Bera, Santanu; Kumar, Ravi; Jha, S.N.; Bhattacharyya, D.
• Is Part Of: Progress in nuclear energy. Volume 131(2021)
• Publication Date: 2021-01
• Subjects: Borosilicate glass -- Uranium oxidation state -- XPS studies of uranium in glass -- XAS -- X-ray diffraction; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 333.7924
• DOI: 10.1016/j.pnucene.2020.103579
• Languages: English
• ISSNs: 0149-1970

Abstract

Abstract: The modified sodium borosilicate glass was synthesized by incorporating CaO, TiO2 and Al2 O3 to the primary glass forming constituents (SiO2, B2 O3 and Na2 O) 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. Graphical abstract: Image 1 Highlights: Modified borosilicate glass 47SiO2 -24B2 O3 -17Na2 O-9.5CaO-1.0Al2 O3 -1.5 TiO2 was prepared. 2–8 mol% of UO3 in the form of U3 O8 was loaded to the modified borosilicate glass. Above 6 mol% of UO3 loading, Na2 U2 O7 separated out from the glass unravelled by XRD studies. XPS studies show the presence of U in two different oxidation states (U 6+ and U 4+ ). EXAFS studies reveal a decrease in coordination of uranium in glass matrix on increasing uranium loading.