American Society of Civil Engineers

Drift Scale Test at Yucca Mountain: Description and Updated Results

by Ralph A. Wagner, M.ASCE, (URSG-Woodward Clyde Federal Service, Las Vegas, NV), Stephen C. Blair, (Lawrence Livermore National Laboratory, Livermore, CA), and Steven R. Sobolik, (Sandia National Laboratories, Albuquerque, NM)
Section: Performance and Evaluation of Tunnels, Excavations, and Retaining Structures, pp. 544-563, (doi:

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Document type: Conference Proceeding Paper
Part of: Performance Confirmation of Constructed Geotechnical Facilities
Abstract: The Drift Scale Test (DST) is an integral part of the U.S. Department of Energy site investigations program to characterize Yucca Mountain and determine its suitability for the permanent disposal of spent nuclear fuel and high-level nuclear waste. The DST is a large-scale, long-term in situ thermal test consisting of a 47.5-meter long drift, 50 wing heaters, and 9 floor heaters. Thermal- mechanical-hydrological-chemical (TMHC) responses of the rock are measured by approximately 3,500 sensors installed in 147 boreholes drilled into the test block. The heating phase of the test, which started on December 3, 1997, is scheduled to continue for four years. It will be followed by a cooling phase of similar duration. During the heating phase, temperature in approximately 10,000 cubic meters of rock will exceed 100 °C. The primary objective of the DST is to gain a more in-depth understanding of TMHC processes anticipated to exist in the local rock mass surrounding the potential repository at Yucca Mountain. The numerical simulations of the DST is an integral part of the development and enhancement of coupled-process models. The following three types of models were used in the analyses: thermal-hydrological (TH), thermal-hydrological-mechanical (THM), and thermal- hydrological-chemical (THC). These analyses and ongoing comparisons to the measured responses have advance the understanding of the complex coupled processes anticipated in the host rock at Yucca Mountain.

ASCE Subject Headings:
In situ tests
Performance characteristics
Radioactive wastes
Rock mechanics
Scale ratio
Thermal analysis
Waste disposal