Transcript Yucca Mountain’s Unsaturated Zone

Yucca Mountain’s Unsaturated Zone
Nick Dosen
Purpose and Methodology
 Determine whether Yucca Mountain Unsaturated Zone
conditions are suitable for a high level nuclear waste
repository
 Will look at:
 UZ models and features
 Infiltration projections
UZ Conceptual Map
Welded Tuffs
 Include the Tiva Canyon and the Topopah Springs welded
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units
High pressures
Fracture flow predominance
Possibility of matrix flow
Fault flow
Nonwelded Tuffs
 Include the Paintbrush and the Calico Hills nonwelded units
 Greater porosity
 Matrix flow
 Lateral flow
 Fault flow
Chloride Model
 Parameters acquired from pore water measurements
 Incorporates the effects of numerous factors
 Results
 PTn lateral flow
 Slower Gw flow
Perched Water
Perched Water
 Causes:
 Contrast in permeability between layers
 Blocks to lateral fault flow
 Significance
 Directly related to radionuclide transport to water table
 Future climate projections and infiltration rates
Infiltration
 High impact on UZ flow
 Directly caused by precipitation
 ppt estimates at about 125 mm/yr
 Infiltration rate estimates range from 5-15 mm/yr
 Temperatures are expected to rise as climate changes
 More ppt = more infiltrating water
Infiltration
Conclusions
 Too much uncertainty to tell
 Would require more accurate models of the various flow
components (lateral flow, infiltration, etc.)
References
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Faybishenko, Boris. “Climatic Forecasting of Net Infiltration at Yucca Mountain Using Analogue Meteorological
Data.” Vadose Zone Journal 6.1 (2007): 77-92.
Hinds, J. Jennifer, Shemin Ge, and Chris J. Fridrich. “Numerical Modeling of Perched Water Under Yucca
Mountain, Nevada.” Ground Water 37.4 (1999): 498-504.
Liu, H.H., G.S. Bodvarsson, and G. Zhang. “Scale dependency of the effective matrix diffusion coefficient.”
Lawrence Berkeley National Laboratory (2003): LBNL Paper LBNL-52824. Retrieved from:
http://escholarship.org/uc/item/4cs4n5w8
Liu, Jianchun, Eric L. Sonnenthal, and G.S. Bodvarsson. “Calibration of Yucca Mountain unsaturated zone flow and
transport model using porewater chloride data.” Lawrence Berkeley National Laboratory (2002): LBNL Paper
LBNL-49871. Retrieved from: http://escholarship.org/uc/item/1vb7n0t6
Pan, Lehua,Yu-ShuWu, and Keni Zhang. “A Modeling Study of Flow Diversion and Focusing in Unsaturated
Fractured Rocks.” Vadose Zone Journal 3. (2004): 233-246
Wu,Yu-Shu, Lu Guoping, Keni Zhang, and G.S. Bodvarsson. “A Mountain-Scale Model for Characterizing
Unsaturated Flow and Transport in Fractured Tuffs of Yucca Mountain.” Vadose Zone Journal 3. (2004): 796-805
Wu,Yu-Shu, Lu Guoping, Keni Zhang, Lehu Pan, and G.S. Bodvarsson. “Analyzing unsaturated flow patterns in
fractured rock using an integrated modeling approach.” Hydrogeology Journal 15.3 (2007): 553-572.
Xaltu, Bill. “Scholastic Study of Solute Transport in a Nonstationary Medium.” Ground Water 44.2 (2006): 222223.
Yang, I.C., Gordon W. Rattray, and Pei Yu. “Interpretation of Chemical and Isotopic Data from Boreholes in the
Unsaturated Zone at Yucca Mountain, Nevada.” United States Geological Survey (1996).
Zhang, Keni,Yu-ShuWu, and James E. Houseworth. “Sensitivity Analysis of Hydrological parameters in Modeling
Flow and Transport in the Unsaturated Zone of Yucca Mountain, Nevada, USA.” Hydrogeology Journal 14.8
(2006): 1599-1619.