Abstraction processes used for the representation of water conducting features in the Yucca Mountain performance assessment

In the United States the Department of Energy (DOE) has been conducting site characterization studies of a potential high-level nuclear waste repository site at Yucca Mountain, Nevada since the early 1980's. As part of this characterization DOE has performed testing on various scales of features which may conduct water through the unsaturated zone and the saturated zone, to determine their basic hydrologic characteristics and potential impacts on waste isolation. Process level conceptual and numeric models of the unsaturated zone flow system and the saturated zone flow system, which incorporate these features, have been developed and used as a foundation for total system performance assessment analysis. Through sensitivity analysis it has been shown that the uncertainty in parameters for water conducting features have a significant effect on performance assessment calculations. (author)