Saturated Zone In-Situ Testing

The purpose of this scientific analysis is to document the results and interpretations of field experiments that test and validate conceptual flow and radionuclide transport models in the saturated zone (SZ) near Yucca Mountain, Nevada. The test interpretations provide estimates of flow and transport parameters used in the development of parameter distributions for total system performance assessment (TSPA) calculations. These parameter distributions are documented in Site-Scale Saturated Zone Transport (SNL 2007 [DIRS 177392]), Saturated Zone Colloid Transport (BSC 2004 [DIRS 170006]), and Saturated Zone Flow and Transport Model Abstraction (SNL 2007 [DIRS 177390]).
Although this TWP was prepared before transition to the Lead Laboratory, it was considered appropriate for developing this report, because it was prepared in compliance with LP-2.29Q-BSC, Planning for Science Activities (a BSC procedure (predecessor)), which corresponds to SCI-PRO-002, Planning for Science Activities (the Lead Laboratory procedure). Specifically, this scientific analysis contributes the following to the assessment of the capability of the SZ to serve as part of a natural barrier for waste isolation for the Yucca Mountain repository system:
• The bases for selection of conceptual flow and transport models in the saturated volcanics and the saturated alluvium located near Yucca Mountain.
• Results and interpretations of hydraulic and tracer tests conducted in saturated fractured volcanics at the C-wells complex near Yucca Mountain. The test interpretations include estimates of hydraulic conductivities, anisotropy in hydraulic conductivity, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, matrix diffusion coefficients, fracture apertures, and colloid transport parameters.
• Results and interpretations of hydraulic and tracer tests conducted in saturated alluvium at the Alluvial Testing Complex (ATC) located at the southwestern corner of the Nevada Test Site (NTS) and at Nye County Site 22, located just east of Fortymile Wash about 4.5 km northeast of the ATC (and about 13 km from the repository). The test interpretations include estimates of hydraulic conductivities, storativities, total porosities, effective porosities, longitudinal dispersivities, matrix diffusion mass transfer coefficients, and colloid transport parameters.
• Comparisons of sorption parameter estimates for a reactive solute tracer (lithium ion) derived from the C-wells field tracer tests and laboratory tests using C-wells core samples.
• Sorption parameter estimates for lithium ion derived from laboratory tests using alluvium samples from ATC well NC-EWDP-19D and from well NC-EWDP-22PC. For the latter well, these estimates allow a comparison of laboratory- and field-derived sorption parameters to be made for saturated alluvium (cross-hole tests were never conducted at the ATC, so a similar comparison is not possible for that location).