A Comparison of the Performance of Nuclear Waste Glasses by Modeling

Abstract

The reprocessing of spent fuel from nuclear reactors and processing of fuels for defense purposes have generated large volumes of high-level liquid waste that need to be immobilized prior to final storage. For immobilization, the wastes must be converted to a less soluble solid, and, although other waste forms exist, glass currently appears to be the choice for the transuranic-containing portion of the reprocessed waste. Once produced, this glass will be sent in canisters to a geologic repository located some 200 to 500 m below the surface of the earth.

SON68 nuclear glass dissolution kinetics: Current state of knowledge and basis of the new GRAAL model

“…Under these conditions, a fraction of the dissolved silicon recondenses to form an amorphous, porous, hydrated phase commonly referred to as the 'gel' [23]. Until recently, two opposing approaches dominated in the literature to account for the rate drop, one based on the chemical affinity expressed with respect to the initial glass, and the other on the passivating effect of the alteration gel [24,25]. The efforts undertaken notably in the framework of the European GLAMOR Program [2] have since contributed to the convergence of these two approaches.…”

Aem Analyses of SRL 131 Glass Altered as a Function of SA/V

“…where Ci refers to the concentration of species i: t is time, SA is the glass surface area, V is volume, and Csat i refers to the saturation concentration of species with respect to secondary alteration phases, a value dependent on the overall solution composition and temperature [8,9]. The constant k includes the temperature dependency of the reaction and the constant n is an empirical factor related to the order of the reaction.…”

Corrosion issues of radioactive waste packages in geological disposal systems

“…The most typical application is for the calculation of the progress of glass dissolution ('reaction progress'), by calculating the evolving composition of the leachate. This is of particular relevance in case secondary phases are formed in solution, which are experimentally known to potentially enhance glass dissolution (Grambow, 1991;Van Iseghem and Grambow, 1988;Grambow and Strachan, 1988). Geochemical models are also used to calculate and predict the transport of elements leached from the glass (both matrix elements and radionuclides) through near field barriers (Grambow and Giffaut, 2006).…”