Thermal response to emplacement of nuclear waste in long, horizontal boreholes
The Nevada Nuclear Waste Storage Investigations (NNWSI) Project, is examining the feasibility of siting a repository for high-level nuclear waste at Yucca Mountain on and adjacent to the Nevada Test Site. This work, intended to extend our understanding of repository design options and their impacts on expected temperatures at representative locations, was funded by the NNWSI Project. The emplacement of nuclear waste in long, horizontal boreholes appears to offer several advantages when compared to the more conventional scheme of floor emplacement. The most important one is a significant reduction in the amount of material mined. The capability also exists for leaving a short distance (called the standoff distance) near both ends of the emplacement tube empty, which reduces the access drift temperature rise significantly in the first 30 years or so after nuclear waste emplacement. This paper discusses the results of an investigation of the temperature field around horizontal emplacement repositories containing either spent fuel, commercial high-level waste, or defense high-level waste. The effects of variation of the Gross Thermal Loading (GTL), canister power, and rock type on the temperature field were investigated. The effect of standoff distance on access drift temperature rise was investigated with a reasonable distance, under most conditions, being about 10 m. GTLs of 100 kW/acre or canister loadings above 2.2 kW appear to be too high, especially if the emplacement medium is a zeolitized tuff which has a low thermal conductivity and diffusivity. The computer code used in this investigation was, by necessity, simple and quick running. The limitation of this code was that because thermal properties were constrained to be constant, the effects of boiling could not be included. This problem is not severe if the boiling region is small compared to the region of interest.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 59497
- Report Number(s):
- SAND--82-2497; ON: DE83011870
- Country of Publication:
- United States
- Language:
- English
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