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Evaluation of the effects of underground water usage and spillage in the Exploratory Studies Facility; Yucca Mountain Site Characterization Project

Description: The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level radioactive waste repository. Analyses reported herein were performed to support the design of site characterization activities so that these activities will have a minimal impact on the ability of the site to isolate waste and a minimal impact on underground tests performed as part of the characterization process. These analyses examine the effect of water to be used in the underground construction and testing activities for the Exploratory Studies Facility on in situ conditions. Underground activities and events where water will be used include construction, expected but unplanned spills, and fire protection. The models used predict that, if the current requirements in the Exploratory Studies Facility Design Requirements are observed, water that is imbibed into the tunnel wall rock in the Topopah Springs welded tuff can be removed over the preclosure time period by routine or corrective ventilation, and also that water imbibed into the Paintbrush Tuff nonwelded tuff will not reach the potential waste storage area.
Date: December 1, 1993
Creator: Dunn, E. & Sobolik, S.R.
Partner: UNT Libraries Government Documents Department

Estimation of the impact of water movement from sewage and settling ponds near a potential high level radioactive waste repository in Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

Description: The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface-based and underground testing. Analyses have been performed to design site characterization activities with minimal impact on the ability of the site to isolate waste, and on tests performed as part of the characterization process. One activity of site characterization is the construction of an Exploratory Studies Facility, which may include underground shafts, drifts, and ramps, and the accompanying ponds used for the storage of sewage water and muck water removed from construction operations. The information in this report pertains to the two-dimensional numerical calculations modelling the movement of sewage and settling pond water, and the potential effects of that water on repository performance and underground experiments. This document contains information that has been used in preparing Appendix I of the Exploratory Studies Facility Design Requirements document (ESF DR) for the Yucca Mountain Site Characterization Project.
Date: February 1, 1992
Creator: Sobolik, S.R. & Fewell, M.E.
Partner: UNT Libraries Government Documents Department

Estimations of the extent of migration of surficially applied water for various surface conditions near the potential repository perimeter; Yucca Mountain Site Characterization Project

Description: The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface-based and underground testing. Analyses have been performed to support the design of site characterization activities so to have minimal impact on the ability of the site to isolate waste, and on tests performed as part of the characterization process. Two examples of site characterization activities are the construction of an Exploratory Studies Facility, which may include underground shafts, drifts, and ramps, and surface-based testing activities, which may require borehole drilling, excavation of test pits, and road watering for dust control. The information in this report pertains to two-dimensional numerical calculations modeling the movement of surficially applied water and the potential effects of that water on repository performance and underground experiments. This document contains information that has been used in preparing recommendations for two Yucca Mountain Site Characterization Project documents: Appendix I of the Exploratory Studies Facility Design Requirements document, and the Surface-Based Testing Field Requirements Document.
Date: December 1, 1993
Creator: Sobolik, S.R. & Fewell, M.E.
Partner: UNT Libraries Government Documents Department

Preliminary validation of rock mass models by comparison to laboratory frictional sliding experiments

Description: The U.S. Department of Energy`s (DOE) Yucca Mountain Site Characterization Project (YMP) is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization will be facilitated by the construction of an Exploratory Studies Facility (ESF). The ESF and potential repository will be excavated from both nonwelded and welded ashflow tuff with varying rock quality (degree of welding, rock mass strength, etc.) and fault and fracture characteristics. Design concerns for the construction of these facilities include the integrity of the structure during underground testing operations and, if it occurs, the emplacement and storage of high-level nuclear waste which could increase the local temperatures in the underground rock mass to as high as 300{degrees}C. Because of the associated issues regarding personnel and long-term environmental safety, sophisticated jointed rock mass models will be required to provide a high degree of confidence for decisions regarding the design, site characterization, and licensing of such facilities. The objective of the work documented in this report is to perform code validation calculations for three rock-mass computer models. The three rock-mass computer models used for this report are the discrete element code UDEC, Version 1.82; and the finite element continuum joint models JAC2D Version 5.10 and JAS3D Version 1.1. The rock mass behavior predicted by the models are compared to the results of laboratory experiments on layered polycarbonate (Lexan) and granite plate experiments. These experiments examine the rock mass behavior of well-defined jointed rock structures or models of jointed structures under uniaxial and biaxial loading. The laboratory environment allows control over the boundary conditions, material properties, and quality and quantity of the data obtained.
Date: September 1, 1996
Creator: Sobolik, S.R. & Miller, J.D.
Partner: UNT Libraries Government Documents Department

Movement of shaft and drift construction water in Yucca Mountain, Nevada: An extended study; Yucca Mountain Site Characterization Project

Description: The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface-based and underground testing. Analyses have been performed to design site characterization activities with minimal impact on the ability of the site to isolate waste, and on tests performed as part of the characterization process. One activity of site characterization is the construction of an Exploratory Studies Facility, for which many design options are being considered, including shafts, drifts, and ramps. The information in this report pertains to: (1) engineering calculations of the potential distribution of residual water from constructing the shafts and drifts; (2) numerical calculations predicting the movement of residual construction water from the shaft and drift walls into the rock; and (3) numerical calculations of the movement of residual water and how the movement is affected by ventilation. This document contains information that has been used in preparing Appendix 1 of the Exploratory Studies Facility Design Requirements document for the Yucca Mountain Project.
Date: December 1, 1991
Creator: Sobolik, S.R.; Fewell, M.E. & Eaton, R.R.
Partner: UNT Libraries Government Documents Department

Investigation of fracture-matrix interaction: Preliminary experiments in a simple system

Description: Paramount to the modeling of unsaturated flow and transport through fractured porous media is a clear understanding of the processes controlling fracture-matrix interaction. As a first step toward such an understanding, two preliminary experiments have been performed to investigate the influence of matrix imbibition on water percolation through unsaturated fractures in the plane normal to the fracture. Test systems consisted of thin slabs of either tuff or an analog material cut by a single vertical fracture into which a constant fluid flux was introduced. Transient moisture content and solute concentration fields were imaged by means of x-ray absorption. Flow fields associated with the two different media were significantly different owing to differences in material properties relative to the imposed flux. Richards` equation was found to be a valid means of modeling the imbibition of water into the tuff matrix from a saturated fracture for the current experiment.
Date: December 31, 1992
Creator: Foltz, S.D.; Tidwell, V.C.; Glass, R.J. & Sobolik, S.R.
Partner: UNT Libraries Government Documents Department

Estimation of the limitations for surficial water addition above a potential high level radioactive waste repository at Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

Description: The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface-based and underground testing. Analyses have been performed to design site characterization activities with minimal impact on the ability of the site to isolate waste, and on tests performed as part of the characterization process. One activity of site characterization is the construction of an Exploratory Studies Facility, consisting of underground shafts, drifts, and ramps, and the accompanying surface pad facility and roads. The information in this report addresses the following topics: (1) a discussion of the potential effects of surface construction water on repository-performance, and on surface and underground experiments; (2) one-dimensional numerical calculations predicting the maximum allowable amount of water that may infiltrate the surface of the mountain without affecting repository performance; and (3) two-dimensional numerical calculations of the movement of that amount of surface water and how the water may affect repository performance and experiments. The results contained herein should be used with other site data and scientific/engineering judgement in determining controls on water usage at Yucca Mountain. This document contains information that has been used in preparing Appendix I of the Exploratory Studies Facility Design Requirements document for the Yucca Mountain Site Characterization Project.
Date: January 1, 1992
Creator: Fewell, M.E.; Sobolik, S.R. & Gauthier, J.H.
Partner: UNT Libraries Government Documents Department

Sensitivity of hydrological performance assessment analysis to variations in material properties, conceptual models, and ventilation models

Description: The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface- based and underground testing. Analyses have been performed to support the design of an Exploratory Studies Facility (ESF) and the design of the tests performed as part of the characterization process, in order to ascertain that they have minimal impact on the natural ability of the site to isolate waste. The information in this report pertains to sensitivity studies evaluating previous hydrological performance assessment analyses to variation in the material properties, conceptual models, and ventilation models, and the implications of this sensitivity on previous recommendations supporting ESF design. This document contains information that has been used in preparing recommendations for Appendix I of the Exploratory Studies Facility Design Requirements document.
Date: July 1, 1996
Creator: Sobolik, S.R.; Ho, C.K.; Dunn, E.; Robey, T.H. & Cruz, W.T.
Partner: UNT Libraries Government Documents Department

Results of the Single Heater Test at Yucca Mountain, Nevada

Description: The Yucca Mountain Project conducted a Single Heater Test (SHT) in the Exploratory Studies Facility at Yucca Mountain. During the nine month-long heating phase, approximately 4 m{sup 3} of in situ, fractured, 92% saturated, welded tuff was heated to temperatures above 100 C by a 5 m long, 3.8 kW, horizontal, line heater. In this paper, the thermal data collected during the test (Sandia National Laboratories, 1997) are compared to three numerical simulations (Sobolik et al., 1996) in order to gain insight into the coupled thermal-hydrologic processes. All three numerical simulations rely on the Equivalent Continuum Model (ECM) for reasons of computational efficiency. The ECM assumes that the matrix and the fractures are in thermodynamic equilibrium which allows the thermal and hydrologic properties of the matrix and the fractures to be combined into single, bulk values. The three numerical simulations differ only in their bulk permeabilities and are referred to as the High, Low and Matrix Permeability Models, respectively. In the Matrix Permeability Model, the system behaves as an unfractured porous medium with the properties of the rock matrix.
Date: December 1, 1997
Creator: Ballard, S.; Francis, N.D. & Sobolik, S.R.
Partner: UNT Libraries Government Documents Department

Post-test comparison of thermal-hydrologic measurements and numerical predictions for the in situ single heater test, Yucca Mountain, Nevada

Description: The Single Heater Test (SHT) is a sixteen-month-long heating and cooling experiment begun in August, 1996, located underground within the unsaturated zone near the potential geologic repository at Yucca Mountain, Nevada. During the 9 month heating phase of the test, roughly 15 m{sup 3} of rock were raised to temperatures exceeding 100 C. In this paper, temperatures measured in sealed boreholes surrounding the heater are compared to temperatures predicted by 3D thermal-hydrologic calculations performed with a finite difference code. Three separate model runs using different values of bulk rock permeability (4 microdarcy to 5.2 darcy) yielded significantly different predicted temperatures and temperature distributions. All the models differ from the data, suggesting that to accurately model the thermal-hydrologic behavior of the SHT, the Equivalent Continuum Model (ECM), the conceptual basis for dealing with the fractured porous medium in the numerical predictions, should be discarded in favor of more sophisticated approaches.
Date: June 1, 1998
Creator: Ballard, S.; Francis, N.D.; Sobolik, S.R. & Finley, R.E.
Partner: UNT Libraries Government Documents Department