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Foaming and Antifoaming in Radioactive Waste Pretreatment and Immobilization Processes

Description: Savannah River National Laboratory (SRNL) has reported severe foaminess in the bench scale evaporation of the Hanford River Protection - Waste Treatment Plant (RPP-WPT) envelope C waste. Excessive foaming in waste evaporators can cause carryover of radionuclides and non-radioactive waste to the condensate system. The antifoams used at Hanford and tested by SRNL are believed to degrade and become inactive in high pH solutions. Hanford wastes have been known to foam during evaporation causing excessive down time and processing delays.
Date: March 12, 2005
Creator: Wasan, Darsh T.; Nikolov, Alex D.; Lamber, D.P.; Calloway, T. Bond & Stone, M.E.
Partner: UNT Libraries Government Documents Department

[Materials Research Collaborative Access Team] Final Report - DOE Grant No.DEFG0200ER45811

Description: Operations Funding for the Materials Research Collaborative Access Team. In the proposal they presented five specific objectives for the MR-CAT Insertion Device beam line: (1) enable the accomplishment of the best possible science at MR-CAT; (2) facilitate efficient set-up and operations of a variety of complex materials-related experiments; (3) open the beamlines' facilities to scientists and science projects from non-traditional backgrounds and disciplines, respectively; (4) enable efficient 24 hour use of the beamline through interdisciplinary research teams and appropriate operations support; and (5) develop selected operations modes in support of the MR-CAT institutions, DOE collaborators, and general users.
Date: May 2, 2004
Creator: Segre, Carlo
Partner: UNT Libraries Government Documents Department

Theoretical Investigations of Plasma-Based Accelerators and Other Advanced Accelerator Concepts

Description: Theoretical investigations of plasma-based accelerators and other advanced accelerator concepts. The focus of the work was on the development of plasma based and structure based accelerating concepts, including laser-plasma, plasma channel, and microwave driven plasma accelerators.
Date: May 21, 2004
Creator: Shuets, G.
Partner: UNT Libraries Government Documents Department

Foaming and Antifoaming in Radioactive Waste Pretreatment and Immobilization

Description: Radioactive waste treatment processes usually involve concentration of radionuclides before waste can be immobilized by storing it in stable solid form. Foaming is observed at various stages of waste processing like sludge chemical processing and melter operations. Hence, the objective of this research was to study the mechanisms that produce foaming during nuclear waste treatment, to identify key parameters which aggravate foaming, and to identify effective ways to eliminate or mitigate foaming. Experimental and theoretical investigations of the surface phenomenon, suspension rheology, and bubble generation and interactions that lead to the formation of foam during waste processing were pursued under this EMSP project. Advanced experimental techniques including a novel capillary force balance in conjunction with the combined differential and common interferometry were developed to characterize particle-particle interactions at the foam lamella surfaces as well as inside the foam lamella. Laboratory tests were conducted using a non-radioactive simulant slurry containing high levels of noble metals and mercury similar to the High-Level Waste. We concluded that foaminess of the simulant sludge was due to the presence of colloidal particles such as aluminum, iron, and manganese. We have established the two major mechanisms of formation and stabilization of foams containing such colloidal particles: (1) structural and depletion forces; and (2) steric stabilization due to the adsorbed particles at the surfaces of the foam lamella. Based on this mechanistic understanding of foam generation and stability, an improved antifoam agent was developed by us, since commercial antifoam agents were found to be ineffective in the aggressive physical and chemical environment present in the sludge processing. The improved antifoamer was subsequently tested in a pilot plant at the Savannah River Site (SRS) and was found to be effective. Also, in the SRTC experiment, the irradiated antifoamer appeared to be as effective as nonirradiated antifoamers. Therefore, the ...
Date: February 20, 2002
Creator: Wasan, Darsh T.
Partner: UNT Libraries Government Documents Department