Processing of tetraphenylborate precipitates in the Savannah River Site Defense Waste Processing Facility

Conference · Mon Dec 31 04:00:00 EST 1990

OSTI ID:10133981

Eibling, R E

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
• Country of Publication: United States
• Language: English

Related Subjects

052001
053002
054000
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ABSORPTION
BENZENE
BORATES
CESIUM IONS
FORMIC ACID
HEALTH AND SAFETY
HIGH-LEVEL RADIOACTIVE WASTES
HYDROXYLAMINE
NITRITES
PRECIPITATION
RADIOACTIVE EFFLUENTS
REMOVAL
SAFETY STANDARDS
SAVANNAH RIVER PLANT
STRONTIUM IONS
TITANATES
WASTE PROCESSING