Monitoring the vadose zone in fractured tuff, Yucca Mountain, Nevada
Unsaturated tuff beneath Yucca Mountain, Nevada, is being evaluated by the US Department of Energy as a host rock for a potential repository for high-level radioactive waste. As part of the Nevada Nuclear Waste Storage Investigations Project of the US Department of Energy, the US Geological Survey has been conducting hydrologic, geologic, and geophysical investigations at Yucca Mountain and the surrounding region to provide data evaluation of the potential suitability of the site. Hydrologic investigations of the unsaturated zone at this site were started in 1982. A 17.5-inch- (44.5-centimeter-) diameter borehole (USW UZ-1) was drilled by the reverse-air vacuum-drilling technique to a depth of 1269 feet (387 meters). This borehole was instrumented at 33 depth levels. At 15 of the levels, 3 well screens were embedded in coarse-sand columns. The sand columns were isolated from each other by thin layers of bentonite, columns of silica flour, and isolation plugs consisting of expansive cement. Thermocouple psychrometers and pressure transducers were installed within the screens and connected to the data-acquisition system at the land surface through thermocouple and logging cables. Two of the screens at each level were equipped with access tubes to allow collection of pore-gas samples. In addition to these instruments, 18 heat-dissipation probes were installed within the columns of silica flour, some of which also had thermocouple psychrometers. 20 refs., 13 figs., 2 tabs.
- Research Organization:
- US Geological Survey, Denver, CO (United States); Goodson and Associates, Inc., Denver, CO (United States); Holmes and Narver, Inc., Las Vegas, NV (United States)
- DOE Contract Number:
- AI08-78ET44802
- OSTI ID:
- 59850
- Report Number(s):
- CONF-8511172-8; ON: DE86008850
- Resource Relation:
- Conference: Conference on characterization and monitoring of the vadose zone, Denver, CO (United States), 19-21 Nov 1985; Other Information: PBD: 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
05 NUCLEAR FUELS
YUCCA MOUNTAIN
GEOPHYSICAL SURVEYS
TUFF
MOISTURE
HYDRAULIC CONDUCTIVITY
POROSITY
PERMEABILITY
BOREHOLES
NEUTRON LOGGING
ROCK DRILLING
HIGH-LEVEL RADIOACTIVE WASTES
RADIOACTIVE WASTE DISPOSAL
UNDERGROUND DISPOSAL
MOISTURE GAGES
PSYCHROMETRY
POTENTIAL ENERGY
DATA ACQUISITION
Yucca Mountain Project