Long-term, low-temperature oxidation of PWR spent fuel: Interim transition report

Technical Report · Sun May 01 04:00:00 EDT 1988

OSTI ID:60469

Einziger, R E; Buchanan, H C

Since some of the fuel rods will be breached and eventually most of the cladding will corrode, exposing fuel, one factor influencing the ability of spent fuel to retain radionuclides is its oxidation state in the expected moist air atmosphere. Oxidation of the fuel could split the cladding, exposing additional fuel and changing the leaching characteristics. Thermodynamically, there is no reason why UO{sub 2} should not oxidize completely to UO{sub 3} at repository temperatures. The underlying uncertainty is the rate of oxidation. Extrapolation of higher temperature data indicates that insufficient oxidation to convert all of the fuel to U{sub 3}O{sub 8} will occur during the first 10,000 years. However, lower oxidation states, such as U{sub 4}O{sub 9} and U{sub 3}O{sub 7}, might form. To date, the tests have run between 3200 and 4100 hours out of a planned 16,000-hour duration. Some preliminary conclusions can be drawn: (1) Moisture content of the air has no significant effect on oxidation rate, (2) the data have an uncertainty of 15 to 20%, which must be accounted for in the interpretation of single sample tests, and (3) below 175{degree}C, the oxidation rate is dependent on the particle size in the sample. The smaller particles oxidize more rapidly. 19 refs., 23 figs., 7 tabs.

• Research Organization: Westinghouse Hanford Co., Richland, WA (United States)
• DOE Contract Number: AC06-87RL10930
• OSTI ID: 60469
• Report Number(s): WHC-EP--0070; ON: DE88013497
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
CORROSIVE EFFECTS
HIGH-LEVEL RADIOACTIVE WASTES
LEACHING
NEVADA
OXIDATION
RADIOACTIVE WASTE MANAGEMENT
SPENT FUEL ELEMENTS
TUFF
UNDERGROUND DISPOSAL
YUCCA MOUNTAIN
Yucca Mountain Project