Laboratory characterization and vitrification of Hanford radioactive high-level waste

Conference · Wed May 01 04:00:00 EDT 1991

OSTI ID:5611966

Tingey, J M; Elliott, M L; Larson, D E; Morrey, E V

Radioactive high-level wastes generated at the Department of Energy's Hanford Site are stored in underground carbon steel tanks. Two double-shell tanks contain neutralized current acid waste (NCAW) from the reprocessing of irradiated nuclear fuel in the Plutonium and Uranium Extraction (PUREX) Plant. The tanks were sampled for characterization and waste immobilization process/product development. The high-level waste generated in PUREX was denitrated with sugar to form current acid waste (CAW). The CAW was neutralized'' to a pH of approximately 14 by adding sodium hydroxide to reduce corrosion of the tanks. This neutralized'' waste is called Neutralized Current Acid Waste. Both precipitated solids and liquids are stored in the NCAW waste tanks. The NCAW contains small amounts of plutonium and most of the fission products and americium from the irradiated fuel. NCAW also contains stainless steel corrosion products, and iron and sulfate from the ferrous sulfamate reductant used in the PUREX process. The NCAW will be retrieved, pretreated, and immobilized prior to final disposal. Pretreatment consists of water washing the precipitated NCAW solids for sulfate and soluble salts removal as a waste reduction step prior to vitrification. This waste is expected to be the first waste type to be retrieved and vitrified in the Hanford Waste Vitrification Plant (HWVP). A characterization plan was developed that details the processing of the small-volume NCAW samples through retrieval, pretreatment and vitrification process steps. Physical, rheological, chemical, and radiochemical properties were measured throughout these process steps. The results of nonradioactive simulant tests were used to develop appropriate pretreatment and vitrification process steps. The processing and characterization of simulants and actual NCAW tank samples are used to evaluate the operation of these processes. 3 refs., 1 fig., 4 tabs.

• Research Organization: Pacific Northwest Lab., Richland, WA (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 5611966
• Report Number(s): PNL-SA-19458; CONF-910430--6; ON: DE91012735
• Country of Publication: United States
• Language: English

Related Subjects

050800 -- Nuclear Fuels-- Spent Fuels Reprocessing
052001* -- Nuclear Fuels-- Waste Processing
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ACID NEUTRALIZING CAPACITY
CHEMICAL ANALYSIS
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHEMISTRY
CONTAINERS
DENITRATION
ENERGY SOURCES
FUELS
HANFORD RESERVATION
HIGH-LEVEL RADIOACTIVE WASTES
MANAGEMENT
MATERIALS
NATIONAL ORGANIZATIONS
NUCLEAR FUELS
PH VALUE
PROCESSING
PUREX PROCESS
QUANTITATIVE CHEMICAL ANALYSIS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE PROCESSING
RADIOACTIVE WASTES
RADIOCHEMICAL ANALYSIS
REACTOR MATERIALS
REPROCESSING
SEPARATION PROCESSES
SPENT FUELS
STORAGE
TANKS
UNDERGROUND STORAGE
US DOE
US ERDA
US ORGANIZATIONS
VITRIFICATION
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
WATER CHEMISTRY