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Initial comparison of leach behavior between fully radioactive and simulated nuclear waste glasses through long-term testing

Description: A comparison of glass reactivity between radioactive sludge based and simulated nuclear waste glasses has been made through long-term testing of both glass types for SRL 165, SRL 131, and SRL 200 frit compositions. The data demonstrate that for time periods through 280 days, differences in elemental release to solution up to 400% are observed. However, in general, differences in glass reactivity as measured by the release of boron, lithium, and sodium are less than a factor of two. The differences in reactivity are not large enough to alter the order of glass durability for the different compositions or to change the controlling glass dissolution mechanism. A radiation effect exists, mainly in the influence on the leachate pH, which in turn affects the glass reaction mechanism and rate. The differences in reactivity between fully radioactive and the simulated glasses can be reasonably explained if the controlling reaction mechanism is accounted for. Those differences are glass composition and leaching mechanism dependent. Lithium is found to have the highest elemental release in an ion-exchange dominated glass reaction process, while lithium has a lower release than boron and sodium in a matrix dissolution dominated process, where boron and sodium are usually among the most concentrated solution species.
Date: January 1, 1992
Creator: Feng, Xiangdong & Bates, J.K.
Partner: UNT Libraries Government Documents Department

Vitrification of low-level and mixed wastes

Description: The US Department of Energy (DOE) and nuclear utilities have large quantities of low-level and mixed wastes that must be treated to meet repository performance requirements, which are likely to become even more stringent. The DOE is developing cost-effective vitrification methods for producing durable waste forms. However, vitrification processes for high-level wastes are not applicable to commercial low-level wastes containing large quantities of metals and small amounts of fluxes. New vitrified waste formulations are needed that are durable when buried in surface repositories.
Date: December 31, 1994
Creator: Johnson, T.R.; Bates, J.K. & Feng, Xiangdong
Partner: UNT Libraries Government Documents Department

Self-Assembled Mercaptan on Mesoporous Silica (SAMMS) technology of mercury removal and stabilization

Description: This paper explains the technology developed to produce Self-Assembled Mercaptan on Mesoporous Silica (SAMMS) for mercury removal from aqueous wastewater and from organic wastes. The characteristics of SAMMS materials, including physical characteristics and mercury loading, and its application for mercury removal and stabilization are discussed. Binding kinetics and binding speciations are reported. Preliminary cost estimates are provided for producing SAMMS materials and for mercury removal from wastewater. The characteristics of SAMMS in mercury separation were studied at PNNL using simulated aqueous tank wastes and actual tritiated pump oil wastes from Savannah River Site; preliminary results are outlined. 47 refs., 16 figs., 16 tabs.
Date: September 1, 1997
Creator: Feng, Xiangdong; Liu, Jun & Fryxell, G.E.
Partner: UNT Libraries Government Documents Department