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The Yucca Mountain Project
Laboratory Testing
Liquid Flow in Fractured Rock
The following experiment can be viewed as short Quicktime movies. You need Quicktime and the Quicktime plug-in to view the movies. Because the movie files tend to be large, both large frame and small frame versions of each movies are included. You can seen the phenomena better in the large frame movies, but they may take a reletively long time to download. The data in these movies is preliminary, is for viewing purposes only, and is not to be used for quality affecting work.
Introduction
Liquid flow in fractured rock is not understood well and is very difficult to predict. The proposed disposal of high level nuclear waste in fractured tuffaceous rock at Yucca Mountain is expected to heat the repository environment to temperatures exceeding the boiling point of water. The seepage of water naturally percolating through the mountain will be affected by the heating, which will boil the water. The boiled water will condense in cooler regions, and continue to flow. To better understand seepage in fractures when liquid boiling occurs, we have performed laboratory experiments in fracture models and replicas.
In the following movies, we will observe some behaviors of a liquid in fractures with a boiling-hot region and a cooler region. One of these fractures is assembled from a natural rock fracture face and a
transparent replica of the mating face, one is a transparent replica of the two faces of a natural fracture, and the others are made from rough or flat sandblasted glass. Pentane, which normally boils at 36.1 C, was used instead of water to simplify experimental setup.
Conclusion
We have seen several important flow phenomena in boiling-hot fracture models and replicas including condensation halo formation, film flow on fracture walls, intermittent rivulet flow, focused flow, rapid evaporation events, and gas-driven liquid flow. The importance of these phenomena and for the much larger time and space scales of the proposed high-level nuclear waste repository at Yucca Mountain are topics of on-going study. More detailed information on experimental conditions, sample preparation and identification, and equipment calibration is available in LBNL Report 40467 -"Preferential Flow Paths and Heat Pipes: Results from Laboratory Experiments on Heat-Driven Flow in Natural and Artificial Rock Fractures". This report was prepared under the YMP Quality Assurance Program at Lawrence Berkeley National Laboratory.
Acknowledgments
This work was supported by the Director, Office of Civilian Radioactive Waste Management, U.S. Department of Energy, through the Memorandum Purchase Order EA9013MC5X between TRW Environmental Safety Systems, Inc. and the Ernest Orlando Lawrence Berkeley National Laboratory, under Contract No. DE-AC03-76SF00098.
For more information regarding laboratory testing, please contact:
Tim Kneafsey
510-486-4414
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