Effect of glass composition on waste form durability: A critical review

Abstract

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Glass optimization for vitrification of Hanford Site low-level tank waste

“…This order of durability improvement was consistent with the current understanding of glass chemistry (Feng 1989(Feng ,1994Ellison 1994).…”

“…Alumina increases glass durability by converting the nonbridging oxygen bonds generated by alkalis into bridging oxygen bonds through formation of tetrahedral alumina in the glass structure (Bobkova 1983;Feng 1988;Ellison 1994). There are still plenty of NBO bonds in these high-sodium glasses (Na,O = 20 wt%) after charge-balancing by available alumina in the glass.…”

Analysis of components from drip tests with ATM-10 glass

“…Upon initial contact with water, the chemical potential gradients are steep, particularly for glass-forming components such as SiO, and B,O,, and the reaction progresses rapidly. This initial reaction rate is controlled by the glass composition and is referred to as forward rate of reaction [26,27]. At later times, the water approaches saturation of the ratelimiting components and the reaction rate slows considerably.…”

“…Reaction Mechanisms in Wastc Reaction Abrajano et al [32]. bAlthough the reactions are written explicitly for Si and Na, similar reactions occur for other network-forming and network-modifying elements [26].…”

Performance Modeling Applied to the Treatment and Disposal of a Mixed Waste at the SRS

“…The surface layers may reduce leaching by forming a protective barrier [13], or could cause leaching to increase by altering the solution chemistry [ 11,141. While these three corrosion mechanisms control the mechanism by which glass dissolves, solubility considerations determine the dissolution rate. The dissolution rate is highest initially, when the chemical potential gradient between the glass and the solution, is the greatest [15]. As soluble constituents are released, the driving concentration gradient is decreased, and the corrosion rate declines.…”