Influence of composition of element conforming glass structure to the waste glass characteristic

The spent fuel reactor nuclear generates a high level liquid waste (HLLW) that contains both fission products and actinides, whose composition will vary depending on, among others: type of the reactor, enrichment of the fuel, cooling of the spent fuel, and burn up. The vitrified HLLW was performed with borosilicate glass and smelting the waste glass mixture in a melter at a temperature of 1150 °C, and pouring the mixture into the canister. The different concentration of HLLW requires the composition changing of the glass frit, for the waste glass product with the characteristics that meets the requirements. Silica in the glass frit is one of the elements conforming the structure of the glass, whose amount affects the characteristics of the waste glass. The research on hand studied the change of glass frit composition in this case the influence of SiO₂ content in the glass frit towards the waste glass characteristics i.e. density, melting point and elongation expansion coefficient. SiO₂ content which was studied i.e.: 44 %, 45.3 %, 46 %, 48 % and 48.7 % by weight. The higher the content of SiO₂ results in the higher the density and melting point of the waste glass, and the lower the elongation expansion coefficient. Referenced to the Standard Glass produced by the Japan Atomic Energy Agency (JAEA) that has the characteristics density of 2.74 g/cm³, melting point of 1150 °C and elongation expansion coefficient of 83x10^-7/°C, the waste glass with SiO₂ content up to 48.7 %, the density, melting point and length expansion coefficient was concluded to be within the allowed value. (author)