Waterproofing and Strengthening Volcanic Tuff in Waste Repositories
- Technologies Co, Texas (United States)
- Ph.D. Idaho National Laboratory, Idaho Falls, ID (United States)
Waste repositories from surface trenches and shafts at Los Alamos to drilled tunnels at Yucca Mountain are being built in volcanic Tuff, a soft compacted material that is permeable to water and air. US Department of Energy documents on repository design identify the primary design goal of 'preventing water from reaching the waste canisters, dissolving the canisters and carrying the radioactive waste particles away from the repository'. Designers expect to achieve this by use of multiple barriers along with careful placement of the repository both well above the water table and well above the ground level in a mountain. Though repositories are located in areas that have a historically dry climate to minimize the impact of rainfall infiltration, global warming phenomena may have the potential to alter regional climate patterns - potentially leading to higher infiltration rates. Conventional methods of sealing fractures within volcanic tuff may not be sufficiently robust or long lived to isolate a repository shaft from water for the required duration. A new grouting technology based on molten wax shows significant promise for producing the kind of long term sealing performance required. Molten wax is capable of permeating a significant distance through volcanic tuff, as well as sealing fractures by permeation that is thermally dependent instead of chemically or time dependent. The wax wicks into and saturates tuff even if no fractures are present, but penetrates and fills only the heated area. Heated portions of the rock fill like a vessel. The taffy-like wax has been shown to waterproof the tuff, and significantly increase its resistance to fracture. This wax was used in 2004 for grouting of buried radioactive beryllium waste at the Idaho National Laboratory, chiefly to stop the water based corrosion reactions of the waste. The thermoplastic material contains no water and does not dry out or change with age. Recent studies indicate that this kind of wax material may be inherently resistant to bio-degradation. (authors)
- Research Organization:
- WM Symposia, 1628 E. Southern Avenue, Suite 9 - 332, Tempe, AZ 85282 (United States)
- OSTI ID:
- 21326098
- Report Number(s):
- INIS-US-10-WM-08260; TRN: US10V0497067463
- Resource Relation:
- Conference: WM'08: Waste Management Symposium 2008 - HLW, TRU, LLW/ILW, Mixed, Hazardous Wastes and Environmental Management - Phoenix Rising: Moving Forward in Waste Management, Phoenix, AZ (United States), 24-28 Feb 2008; Other Information: Country of input: France; 17 refs
- Country of Publication:
- United States
- Language:
- English
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