Development and Characterization of Borosilicate Glasses for Immobilization of Plutonium-containing Alkaline Sludges

Abstract

ABSTRACTSeveral glasses were melted using laboratory-scale microwave (MW) equipment to study the vitrification of Pu-containing sludges from the Mining and Chemical Combine in Zheleznogorsk, Russia. This work is part of an effort to identify glass compositions that can be adopted for industrial scale production. The glass must meet durability requirements and have good technological properties for long-term storage and geologic disposal.Electron Probe Analysis (EMPA), scanning electron microscope (SEM) and x-ray methods were used to characterize glasses containing 50 wt% solid sludge residues with high sodium content.Leach tests of 3, 7, 14, and 28 day durations were performed using the MCC-1 method at 90°C. The surface of the glass was analyzed before and after leaching. Based on the observed results, there are differences in the behavior of Pu and U for the glasses tested, and glass durability is dependent on homogeneity, the uranium oxidizing state, and the SiO2/Na2O+Li2O ratio.