Processing of tetraphenylborate precipitates in the Savannah River Site Defense Waste Processing Facility
The Savannah River Site has generated 77 million gallons of high level radioactive waste since the early 1950`s. By 1987, evaporation had reduced the concentration of the waste inventory to 35 million gallons. Currently, the wastes reside in large underground tanks as a soluble fraction stored, crystallized salts, and an insoluble fraction, sludge, which consists of hydrated transition metal oxides. The bulk of the radionuclides, 67 percent, are in the sludge while the crystallized salts and supernate are composed of the nitrates, nitrites, sulfates and hydroxides of sodium, potassium, and cesium. The principal radionuclide in the soluble waste is {sup 137}Cs with traces of {sup 90}Sr. The transformation of the high level wastes into a borosilicate glass suitable for permanent disposal is the goal of the Defense Waste Processing Facility (DWPF). To minimize the volume of glass produced, the soluble fraction of the waste is treated with sodium tetraphenylborate and sodium titanate in the waste tanks to precipitate the radioactive cesium ion and absorb the radioactive strontium ion. The precipitate is washed in the waste tanks and is then pumped to the DWPF. The precipitate, as received, is incompatible with the vitrification process because of the high aromatic carbon content and requires further chemical treatment. Within the DWPF, the precipitate is processed in the Salt Processing Cell to remove the aromatic carbon as benzene. The precipitate hydrolysis process hydrolyzes the tetraphenylborate anion to produce borate anion and benzene. The benzene is removed by distillation, decontaminated and transferred out of the DWPF for disposal.
- Research Organization:
- Westinghouse Savannah River Co., Aiken, SC (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC09-89SR18035
- OSTI ID:
- 10133981
- Report Number(s):
- WSRC-MS-90-162; CONF-900802-21; ON: DE92010187
- Resource Relation:
- Conference: 200. American Chemical Society (ACS) national meeting,Washington, DC (United States),26-31 Aug 1990; Other Information: PBD: [1990]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
CESIUM IONS
PRECIPITATION
STRONTIUM IONS
ABSORPTION
BENZENE
REMOVAL
HIGH-LEVEL RADIOACTIVE WASTES
TITANATES
BORATES
FORMIC ACID
NITRITES
HYDROXYLAMINE
SAFETY STANDARDS
SAVANNAH RIVER PLANT
052001
053002
054000
WASTE PROCESSING
RADIOACTIVE EFFLUENTS
HEALTH AND SAFETY