Structure and Properties of Borosilicate Glass Containing Cesium and/or Strontium Oxides

The study object is borosilicate glass with separate and combined inclusion of Cs and/or Sr oxides in amounts of 5, 10 and 15 wt %. This can be used in the fractionation scheme of liquid high-level waste from the spent nuclear fuel reprocessing. The main attention was paid to their compliance with the quality criteria established in the regulatory document NP-019-15, when studying the physicochemical, thermophysical and mechanical properties of synthesized glass. The glass structure changes slightly relative to the structure of the initial glass frit according to Raman spectroscopy. The exception was glass containing 15 wt % Cs₂O, which contained new bands in the Raman spectra, in addition there were an increase in its molar volume and a decrease in the glass transition temperature. However, these changes had virtually no effect on the thermophysical and mechanical characteristics. The obtained data showed that the glass properties in the studied range of Cs and/or Sr oxides concentrations satisfy the current quality criteria for the product in the form of ¹³⁷Cs and ⁹⁰Sr vitrified concentrates after fractionation of liquid HLW.