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Solidification of SRNL High Activity Drain Waste Feasibility Study

Description: The objective of this study was to demonstrate feasibility of, at the source, solidification of HAD waste and disposal of the resulting solid waste form in E-Area as an alternative to the current practice. Solidification/stabilization is one of four technologies currently being evaluated as alternatives to the current disposal practice. The other technologies are: steam reforming, microwave drying/high temperature treatment, and ion exchange.
Date: October 15, 2004
Creator: LAWRENCE, OJI
Partner: UNT Libraries Government Documents Department

STUDIES OF POTENTIAL INHIBITORS OF SODIUM ALUMINOSILICATE SCALES IN HIGH-LEVEL WASTE EVAPORATION

Description: The Savannah River Site (SRS) has 49 underground storage tanks used to store High Level Waste (HLW). The tank space in these tanks must be managed to support the continued operation of key facilities. The reduction of the tank volumes in these tanks are accomplished through the use of three atmospheric pressure HLW evaporators. For a decade, evaporation of highly alkaline HLW containing aluminum and silicates has produced sodium aluminosilicate scales causing both operation and criticality hazards in the 2H Evaporator System. Segregation of aluminum-rich wastes from silicate-rich wastes minimizes the amount of scale produced and reduces cleaning expenses, but does not eliminate the scaling nor increases operation flexibility in waste process. Similar issues have affected the aluminum refining industry for many decades. Over the past several years, successful commercial products have been identified to eliminate aluminosilicate fouling in the aluminum industry, but have not been utilized in a nuclear environment. Laboratory quantities of three proprietary aluminosilicate scale inhibitors have been produced and been shown to prevent formation of scales. SRNL has been actively testing these potential inhibitors to examine their radiation stability, radiolytic degradation behaviors, and downstream impacts to determine their viability within the HLW system. One of the tested polymers successfully meets the established criteria for application in the nuclear environment. This paper will describe a summary of the methodology used to prioritize laboratory testing protocols based on potential impacts/risks identified for inhibitor deployment at SRS.
Date: February 27, 2008
Creator: Wilmarth, B; Lawrence Oji, L; Terri Fellinger, T; David Hobbs, D & Nilesh Badheka, N
Partner: UNT Libraries Government Documents Department

ANALYSIS OF THE LEACHING EFFICIENCY OF INHIBITED WATER AND TANK 23H SIMULANT IN REMOVING RESIDUES ON TANK 48H WALLS

Description: Solid residues on two sets of thermowell pipe samples from the D2 riser in SRS Tank 48H were characterized. The residue thickness was determined using the ASTM standard D 3483-05 and was found to be three order of magnitudes below the 1mm thickness estimated from an earlier video of the tank cooling coil inspection. The actual estimated thickness ranged from 4 to 20.4 microns. The mass per unit area ranged from 1 to 5.3 milligrams per square inch. The residues appear to consist primarily of potassium tetraphenylborate (39.8 wt% KTPB) and dried salt solution (33.5 wt% total of nitrates, nitrites and oxalate salts), although {approx}30% of the solid mass was not accounted for in the mass balance. No evidence of residue buildup was found inside the pipe, as expected. The residue leaching characteristics were measured by placing one pipe in inhibited water and one pipe in DWPF Recycle simulant. After soaking for less than 4 weeks, the inhibited water was 95.4% effective at removing the residue and the DWPF Recycle simulant was 93.5% effective. The surface appearance of the pipes after leaching tests appeared close to the clean shiny appearance of a new pipe. Total gamma counts of leachates averaged 48.1 dpm/ml, or an equivalent of 2.35E-11 Ci/gm Cs-137 (dry solids basis), which is much lower than the 1.4 E-03 Ci/gm expected for Tank 48 dry slurry solids.
Date: July 31, 2006
Creator: Fondeur, F; Thomas02 White, T; Lawrence Oji, L; Chris Martino, C & Bill Wilmarth, B
Partner: UNT Libraries Government Documents Department