Development of a chemical process using nitric acid-cerium(IV) for decontamination of high-level waste canisters

Technical Report · Wed Jun 01 04:00:00 EDT 1988

DOI:https://doi.org/10.2172/6960355· OSTI ID:6960355

Bray, L A

A simple and effective method was developed for contamination of high-level waste containers. This method of chemical decontamination is applicable to a wide variety of contaminated equipment found in the nuclear industry. The process employs a oxidant system (Ce(IV)) in nitric acid (HNO/sub 3/) solution to chemically mill a thin layer from the canister surface. Contaminated canisters are simply immersed in the solution at a controlled temperature and Ce(IV) concentration level. The spent solution is discarded to the high-level waste stream and added to subsequent glass batches. The Ce(IV)/HNO/sub 3/ solution has been shown to be effective in chemically milling the surface of stainless steel, similar to the electropolishing process, but without the need for an applied electrical current. West Valley (WV) staff had previously evaluated several canister decontamination methods, including electropolishing, liquid abrasive blast, high-pressure water wash, and ultrasonic cleaning, before the Ce(IV)/HNO/sub 3/ redox solution on treatment was selected. The initial concept involved continuous electrochemical regeneration of the ceric ion. Extensive in-cell pumping and close-coupled heat transfer and electrochemical equipment were required. The objective of this study, was to simplify the original concept. 2 refs., 16 figs., 4 tabs.

• Research Organization: Pacific Northwest Lab., Richland, WA (USA)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6960355
• Report Number(s): PNL-6567; ON: DE88013137
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal & Storage
053000 -- Nuclear Fuels-- Environmental Aspects
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BOROSILICATE GLASS
CLEANING
COMPARATIVE EVALUATIONS
CONTAINERS
DECONTAMINATION
FLUIDS
GLASS
HIGH-LEVEL RADIOACTIVE WASTES
HYDROGEN COMPOUNDS
INORGANIC ACIDS
LIQUIDS
MANAGEMENT
MATERIALS
NITRIC ACID
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
UNDERGROUND DISPOSAL
VITRIFICATION
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES