Redox Chemistry in Candidate Glasses for Nuclear Waste Immobilization

An electrochemical series of redox couples, originally developed for Savannah River Laboratory glass frit 131 (SRL‐131) as a reference composition, has been extended to two other alkali borosilicate compositions that are candidate glasses for nuclear waste immobilization. Because no dramatic differences were ascertained in the redox chemistry of selected multivalent elements in SRL‐131 vs that in Savannah River Laboratory glass frit 165 (SRL‐165) and in West Valley glass frit 205 (WV‐205), the comprehensive electrochemical series can readily be applied to a range of nuclear waste glass compositions. In order to alleviate potential problems with foaming and precipitation of insolubles during the processing of the nuclear waste in these glass melts, the [Fe 2+ ]/[Fe 3+ ] ratio of the melt should be between 0.1 and 0.5.