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Title: THREE-DIMENSIONAL STROCHASTIC ROCK-PROPERTY AND UNCERTAINTY MODELS FOR YUCCA MOUNTAIN, NEVADA

Technical Report ·
DOI:https://doi.org/10.2172/776443· OSTI ID:776443

Licensing of Yucca Mountain as a geologic disposal site for high-level nuclear waste will require quantitative predictions of the waste-isolation performance of the rocks that form Yucca Mountain and of the engineered barrier system for an extended period of time into the future. These predictions will require the use of numerical modeling in an attempt to capture the essence of highly complex physical processes, such as ground-water flow and the transport of potential radionuclide contaminants under both unsaturated and saturated conditions. Additional numerical modeling will be required to demonstrate that a mined geologic repository can be constructed safely within the rocks of Yucca Mountain, and that the underground openings will remain stable in the longer term when affected by the thermal pulse of the emplaced waste forms. A fundamental principle involved in the numerical representation of real-world physical processes is that the properties of the modeled domain that are important to that representation must be known ''exhaustively''. Standard procedure in virtually all numerical physical-process modeling is to discretize the model volume into a (large) number of individual elements or grid nodes, assign the necessary attributes to each element or node, and then apply one or more sets of mathematical expressions that are believed to represent the operation of the physical processes under investigation, given some set of external boundary and initial conditions. Because each element or node within the model domain must be assigned a set of properties to represent the variables within the numerical approximation of the process, those properties must be known at each relevant point in space. characterization of a geologic site, such as at Yucca Mountain. Because descriptive characterization is limited both by access (particularly to the subsurface) and by the availability of resources, that description is necessarily incomplete. Therefore, the exhaustive description of a site for purposes of numerical physical-process modeling requires the prior assumption of some type of conceptual model for the site, which is then implemented to assign the values of the necessary properties and other variables at every point in space.

Research Organization:
Yucca Mountain Project, Las Vegas, NV (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
DE-AC01-91RW00134
OSTI ID:
776443
Report Number(s):
MOL.19980504.0098; TRN: US0702865
Country of Publication:
United States
Language:
English