Development of Chemical Treatment Alternatives for Tetraphenylborate Destruction in Tank 48H
This study assessed chemical treatment options for decomposing the tetraphenylborate in High Level Waste (HLW) Tank 48H. Tank 48H, located at the Savannah River Site in Aiken, SC, contains approximately one million liters of HLW. The tetraphenylborate slurry represents legacy material from commissioning of an In Tank Precipitation process to separate radioactive cesium and actinides from the non radioactive chemicals. During early operations, the process encountered an unplanned chemical reaction that catalytically decomposed the excess tetraphenylborate producing benzene. Subsequent research indicated that personnel could not control the operations within the existing equipment to both meet the desired treatment rate for the waste and maintain the benzene concentration within allowable concentrations. Since then, the Department of Energy selected an alternate treatment process for handling high-level waste at the site. However, the site must destroy the tetraphenylborate before returning the tank to HLW service. The research focuses on identifying treatments to decompose tetraphenylborate to the maximum extent feasible, with a preference for decomposition methods that produce carbon dioxide rather than benzene. A number of experiments examined whether the use of oxidants, catalysts or acids proved effective in decomposing the tetraphenylborate. Additional experiments developed an understanding of the solid, liquid and gas decomposition products. The testing identified several successful treatment options including: an iron catalyst combined with hydrogen peroxide (Fenton's reagent) with added acid; sodium permanganate with added acid; and copper catalyst with added acid. A mistake occurred in the selection and make-up of the Tank 48H simulant recipe which led to an under representation of the amount of monosodium titanate and insoluble sludge solids compared to the simulant target. The amount of added MST and sludge proved about a factor of 40 low relative to the measured Tank 48H values. The MST and sludge are insoluble solids that were likely inert in the testing completed. As a result, the mistake had no impact on the testing. Any future Tank 48H research should be completed using the latest Tank 48H simulant recipe.
- Research Organization:
- Savannah River Site (SRS), Aiken, SC (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC09-96SR18500
- OSTI ID:
- 824573
- Report Number(s):
- WSRC-MS-2002-00786, Rev. 1; TRN: US0402097
- Resource Relation:
- Conference: AIChE 2003 Spring National Meeting, New Orleans, LA (US), 03/30/2003--04/02/2003; Other Information: PBD: 4 May 2004
- Country of Publication:
- United States
- Language:
- English
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