Predicting spent fuel oxidation states in a tuff repository

Conference · Thu Dec 31 04:00:00 EST 1987

OSTI ID:60356

Einziger, R E; Woodley, R E

Nevada Nuclear Waste Storage Investigations Project (NNWSI) is studying the suitability of the tuffaceous rocks at Yucca Mountain as a waste repository for spent fuel disposal. The oxidation state of the LWR spent fuel in the moist air environment of a tuff repository could be a significant factor in determining its leaching and dissolution characteristics. Predictions as to which oxidation states would be present are important in analyzing such a repository and thus the present study was undertaken. A set of TGA (thermogravimetric analysis) tests were conducted on well-controlled samples of irradiated PWR fuel with time and temperature as the only variables. The tests were conducted between 140 and 225{sup 0}C for a duration up to 2200 hours. The weight gain curves were analyzed in terms of diffusion through a layer of U{sub 3}O{sub 7}, diffusion into the grains to form a solid solution, a simplified empirical representation of a combination of grain boundary diffusion and bulk grain oxidation. Reaction rate constants were determined in each case, but analysis of these data could not establish a definitive mechanism. 21 refs., 10 figs., 3 tabs.

• Research Organization: Hanford Engineering Development Lab., Richland, WA (United States)
• DOE Contract Number: AC06-76FF02170
• OSTI ID: 60356
• Report Number(s): HEDL-SA--3627; CONF-870437--3; ON: DE88005708
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
DISSOLUTION
FORECASTING
HIGH-LEVEL RADIOACTIVE WASTES
LEACHING
MATHEMATICAL MODELS
NEVADA
OXIDATION
SPENT FUELS
TUFF
UNDERGROUND DISPOSAL
YUCCA MOUNTAIN
Yucca Mountain Project