PNNL

Abstract

Studies were performed to develop and test a glass formulation for immobilization of sodium-bearing waste (SBW), which is a high soda, acidic, high-activity waste stored at the Idaho National Engineering and Environmental Laboratory (INEEL) in 10 underground tanks. It was determined in previous studies that SBW?s sulfur content dictates its loading in borosilicate glasses to be melted by currently assumed processes. If the sulfur content (which is ~4.5 mass% SO3 on a non-volatile oxide basis in SBW) of the melter feed is too high, then a molten, alkali-sulfate-containing salt phase accumulates on the melt surface. The avoidance of salt accumulation during the melter process and the maximization of sulfur incorporation into the glass melt were the main focus of this development work. A glass was developed for 20 mass% SBW (on a non-volatile oxide basis), which contained 0.91 mass% SO3, that met all the processing and product-quality constraints determined for SBW vitrification at a planned INEEL treatment plant?SBW-22-20. This paper summarizes the formulation efforts and presents the data developed on a series of glasses with simulated SBW.