HR: 0830h
AN: H21D-0840    [PDF]
TI: Multiscale Model Simulations of Temperature and Relative Humidity for the License Application of the Proposed Yucca Mountain Repository
AU: * Buscheck, T
EM: buscheck1@llnl.gov
AF: Lawrence Livermore National Laboratory, P.O. Box 808 L-646, Livermore, CA 94550 United States
AU: Glascoe, L
EM: glascoe@llnl.gov
AF: Lawrence Livermore National Laboratory, P.O. Box 808 L-646, Livermore, CA 94550 United States
AU: Sun, Y
EM: sun4@llnl.gov
AF: Lawrence Livermore National Laboratory, P.O. Box 808 L-646, Livermore, CA 94550 United States
AU: Gansemer, J
EM: gansemer@llnl.gov
AF: Lawrence Livermore National Laboratory, P.O. Box 808 L-646, Livermore, CA 94550 United States
AU: Lee, K
EM: lee23@llnl.gov
AF: Lawrence Livermore National Laboratory, P.O. Box 808 L-646, Livermore, CA 94550 United States
AB: For the proposed Yucca Mountain geologic repository for high-level nuclear waste, the planned method of disposal involves the emplacement of cylindrical packages containing the waste inside horizontal tunnels, called emplacement drifts, bored several hundred meters below the ground surface. The emplacement drifts reside in highly fractured, partially saturated volcanic tuff. An important phenomenological consideration for the licensing of the proposed repository at Yucca Mountain is the generation of decay heat by the emplaced waste and the consequences of this decay heat. Changes in temperature will affect the hydrologic and chemical environment at Yucca Mountain. A thermohydrologic-modeling tool is necessary to support the performance assessment of the Engineered Barrier System (EBS) of the proposed repository. This modeling tool must simultaneously account for processes occurring at a scale of a few tens of centimeters around individual waste packages, for processes occurring around the emplacement drifts themselves, and for processes occurring at the multi-kilometer scale of the mountain. Additionally, many other features must be considered including non-isothermal, multiphase-flow in fractured porous rock of variable liquid-phase saturation and thermal radiation and convection in open cavities. The Multiscale Thermohydrologic Model (MSTHM) calculates the following thermohydrologic (TH) variables: temperature, relative humidity, liquid-phase saturation, evaporation rate, air-mass fraction, gas-phase pressure, capillary pressure, and liquid- and gas-phase fluxes. The TH variables are determined as a function of position along each of the emplacement drifts in the repository and as a function of waste-package (WP) type. These variables are determined at various generic locations within the emplacement drifts, including the waste package and drip-shield surfaces and in the invert; they are also determined at various generic locations in the adjoining host rock; these variables are determined every 20 m for each emplacement drift in the repository. The MSTHM accounts for 3-D drift-scale and mountain-scale heat flow and captures the influence of the key engineering-design variables and natural-system factors affecting TH conditions in the emplacement drifts and adjoining host rock. Presented is a synopsis of recent MSTHM calculations conducted to support the Total System Performance Assessment for the License Application (TSPA-LA). This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1833 Hydroclimatology
DE: 1866 Soil moisture
DE: 1878 Water/energy interactions
SC: Hydrology [H]
MN: 2003 Fall Meeting