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Title: Recent nickel-base alloy is vital to corrosion control in nuclear fuel recovery

Journal Article · · Chem. Process. (Chicago); (United States)
OSTI ID:5365386

Government owned nuclear fuel from naval ship reactors, fuel element rods from Core 2 of the Shippingport, PA, pressurized water reactor, and from a variety of experimental reactors is processed to recover U-235 enriched uranium. The uranium extracted from the dissolved fuel elements is purified, converted to uranium oxide, and shipped to Oak Ridge, TN, to make fresh fuel elements. Standard practice is to optimize the production process and then select materials of construction for the equipment. The procedure had to be reversed for the Fluorinel facility because of extremely corrosive conditions sometimes encountered during the process. Selection of materials and construction of the equipment are critical because even the slightest leakage of the fluids cannot be tolerated, and repairs to highly radioactive equipment are very difficult. There are several dissolution systems, each designed to process a different type of fuel element, prior to the recovery of the uranium in the extraction process. Preliminary experiments indicated that nickel-base alloys were the only reasonable possibilities for construction of the dissolver, complexer tanks, off-gas condenser and associated piping. Alloy C-4 exhibits excellent resistance to many corrosives including mineral and organic acids, solvents, and to chlorine and its salts that cause stress corrosion cracking. Alloy C-4 was selected as the best available material but the corrosion rates were still higher than might be accepted in the chemical processing industry. It was therefore necessary to determine the influence of concentration and other process variables on corrosion rate, and then to modify the dissolution and complexing process to minimize the corrosion problem.

Research Organization:
Exxon Nuclear Idaho Co., Idaho Falls, ID
OSTI ID:
5365386
Journal Information:
Chem. Process. (Chicago); (United States), Vol. 44:14
Country of Publication:
United States
Language:
English