Predicting spent fuel oxidation states in a tuff repository
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
- Resource Relation:
- Conference: Workshop on chemical reactivity of oxide fuel and fission product release, Gloucestershire (United Kingdom), 6-9 Apr 1987; Other Information: PBD: 1987
- Country of Publication:
- United States
- Language:
- English
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