Near-drift thermal analysis including combined modes of conduction, convection, and radiation
- Sandia National Labs., Albuquerque, NM (United States)
The performance of waste packages containing high-level nuclear wastes at underground repositories such as the potential repository at Yucca Mountain, Nevada, depends, in part, on the thermodynamic environment immediately surrounding the buried waste packages. For example, degradation of the waste packages can be caused by corrosive and microbial processes, which are influenced by both the relative humidity and temperature within the emplacement drifts. Gansemer and Lamont cite a critical relative humidity of 70-75%, above which a water film may form on the container surface to initiate pitting and subsequent corrosion. Therefore, appropriate models of thermal and fluid transport near the waste package are necessary to predict the thermodynamic environment and performance of the waste packages. However, past models and simulations of the near-field at Yucca Mountain have made simplifying assumptions with regards to the thermal and fluid transport near the waste packages. Convection in an empty drift is often ignored, and radiation from the waste packages to the drift wall is usually lumped into an effective thermal conductivity of the air surrounding the waste packages. In this paper, the effects of conduction, convection, and radiation are investigated for a heat-generating waste package in an empty drift. Simulations explicitly modeling radiation from the waste package to the drift wall are compared to simulations using only conduction. Temperatures, relative humidities, and vapor mass fractions are compared at various locations within the drift. In addition, the effects of convection on relative humidity and moisture distribution within the drift are presented.
- Research Organization:
- American Society of Civil Engineers, New York, NY (United States); American Nuclear Society, La Grange Park, IL (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 405284
- Report Number(s):
- CONF-960421--
- Country of Publication:
- United States
- Language:
- English
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