Download or read book An Updated Site Scale Saturated Zone Ground Water Transport Model for Yucca Mountain written by and published by . This book was released on 2007 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Updated Site Scale Saturated Zone Ground Water Transport Model For Yucca Mountain written by P. Reimus and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Yucca Mountain site scale saturated zone transport model has been revised to incorporate the updated flow model based on a hydrogeologic framework model using the latest lithology data, increased grid resolution that better resolves the geology within the model domain, updated Kd distributions for radionuclides of interest, and updated retardation factor distributions for colloid filtration. The resulting numerical transport model is used for performance assessment predictions of radionuclide transport and to guide future data collection and modeling activities. The transport model results are validated by comparing the model transport pathways with those derived from geochemical data, and by comparing the transit times from the repository footprint to the compliance boundary at the accessible environment with those derived from {sup 14}C-based age estimates. The transport model includes the processes of advection, dispersion, fracture flow, matrix diffusion, sorption, and colloid-facilitated transport. The transport of sorbing radionuclides in the aqueous phase is modeled as a linear, equilibrium process using the Kd model. The colloid-facilitated transport of radionuclides is modeled using two approaches: the colloids with irreversibly embedded radionuclides undergo reversible filtration only, while the migration of radionuclides that reversibly sorb to colloids is modeled with modified values for sorption coefficient and matrix diffusion coefficients. Model breakthrough curves for various radionuclides at the compliance boundary are presented along with their sensitivity to various parameters.
Download or read book Water Level Data Analysis for the Saturated Zone Site Scale Flow and Transport Model written by K. Rehfeldt and published by . This book was released on 2004 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is an updated analysis of water-level data performed to provide the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]) (referred to as the saturated zone (SZ) site-scale flow model or site-scale SZ flow model in this report) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for calibration of groundwater flow models. This report also contains an expanded discussion of uncertainty in the potentiometric-surface map. The analysis of the potentiometric data presented in Revision 00 of this report (USGS 2001 [DIRS 154625]) provides the configuration of the potentiometric surface, target heads, and hydraulic gradients for the calibration of the SZ site-scale flow model (BSC 2004 [DIRS 170037]). Revision 01 of this report (USGS 2004 [DIRS 168473]) used updated water-level data for selected wells through the year 2000 as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain based on an alternative interpretation of perched water conditions. That revision developed computer files containing: Water-level data within the model area (DTN: GS010908312332.002); A table of known vertical head differences (DTN: GS010908312332.003); and A potentiometric-surface map (DTN: GS010608312332.001) using an alternative concept from that presented by USGS (2001 [DIRS 154625]) for the area north of Yucca Mountain. The updated water-level data presented in USGS (2004 [DIRS 168473]) include data obtained from the Nye County Early Warning Drilling Program (EWDP) Phases I and II and data from Borehole USW WT-24. This document is based on Revision 01 (USGS 2004 [DIRS 168473]) and expands the discussion of uncertainty in the potentiometric-surface map. This uncertainty assessment includes an analysis of the impact of more recent water-level data and the impact of adding data from the EWDP Phases III and IV wells. In addition to being utilized by the SZ site-scale flow model, the water-level data and potentiometric-surface map contained within this report will be available to other government agencies and water users for groundwater management purposes. The potentiometric surface defines an upper boundary of the site-scale flow model and provides information useful to estimation of the magnitude and direction of lateral groundwater flow within the flow system. Therefore, the analysis documented in this revision is important to SZ flow and transport calculations in support of total system performance assessment (TSPA).
Download or read book Hydrogeologic Framework Model for the Saturated Zone Site Scale Flow written by Z. Peterman and published by . This book was released on 2003 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yucca Mountain is being evaluated as a potential site for development of a geologic repository for the permanent disposal of spent nuclear fuel and high-level radioactive waste. Ground water is considered to be the principal means for transporting radionuclides that may be released from the potential repository to the accessible environment, thereby possibly affecting public health and safety. The ground-water hydrology of the region is a result of both the arid climatic conditions and the complex geology. Ground-water flow in the Yucca Mountain region generally can be described as consisting of two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick, generally deep-lying, Paleozoic carbonate rock sequence. Locally within the potential repository area, the flow is through a vertical sequence of welded and nonwelded tuffs that overlie the carbonate aquifer. Downgradient from the site, these tuffs terminate in basin fill deposits that are dominated by alluvium. Throughout the system, extensive and prevalent faults and fractures may control ground-water flow. The purpose of this Analysis/Modeling Report (AMR) is to document the three-dimensional (3D) hydrogeologic framework model (HFM) that has been constructed specifically to support development of a site-scale ground-water flow and transport model. Because the HFM provides the fundamental geometric framework for constructing the site-scale 3D ground-water flow model that will be used to evaluate potential radionuclide transport through the saturated zone (SZ) from beneath the potential repository to down-gradient compliance points, the HFM is important for assessing potential repository system performance. This AMR documents the progress of the understanding of the site-scale SZ ground-water flow system framework at Yucca Mountain based on data through July 1999. The AMR documents a geometric model of the site HFM. This HFM provides a simplified 3D interpretation of the hydrostratigraphy and structure within the site SZ flow and transport model domain. This AMR documents data input, modeling methods, assumptions, uncertainties and limitations of the model results, and qualification status of the model. The primary data types from which the HFM was constructed are geologic maps and sections, borehole data, geophysical data (resistivity, seismic, magnetic and gravity), and existing geologic framework models.
Download or read book Water Level Data Analysis for the Saturated Zone Site Scale Flow and Transport Model written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This Analysis/Model Report (AMR) documents an updated analysis of water-level data performed to provide the saturated-zone, site-scale flow and transport model (CRWMS M & O 2000) with the configuration of the potentiometric surface, target water-level data, and hydraulic gradients for model calibration. The previous analysis was presented in ANL-NBS-HS-000034, Rev 00 ICN 01, Water-Level Data Analysis for the Saturated Zone Site-Scale Flow and Transport Model (USGS 2001). This analysis is designed to use updated water-level data as the basis for estimating water-level altitudes and the potentiometric surface in the SZ site-scale flow and transport model domain. The objectives of this revision are to develop computer files containing (1) water-level data within the model area (DTN: GS010908312332.002), (2) a table of known vertical head differences (DTN: GS0109083 12332.003), and (3) a potentiometric-surface map (DTN: GS010608312332.001) using an alternate concept from that presented in ANL-NBS-HS-000034, Rev 00 ICN 01 for the area north of Yucca Mountain. The updated water-level data include data obtained from the Nye County Early Warning Drilling Program (EWDP) and data from borehole USW WT-24. In addition to being utilized by the SZ site-scale flow and transport model, the water-level data and potentiometric-surface map contained within this report will be available to other government agencies and water users for ground-water management purposes. The potentiometric surface defines an upper boundary of the site-scale flow model, as well as provides information useful to estimation of the magnitude and direction of lateral ground-water flow within the flow system. Therefore, the analysis documented in this revision is important to SZ flow and transport calculations in support of total system performance assessment.
Download or read book Hydrogeologic Framework Model for the Saturated Zone Site Scale Flow and Transport Model written by T. Miller and published by . This book was released on 2004 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this report is to document the 19-unit, hydrogeologic framework model (19-layer version, output of this report) (HFM-19) with regard to input data, modeling methods, assumptions, uncertainties, limitations, and validation of the model results in accordance with AP-SIII. 10Q, Models. The HFM-19 is developed as a conceptual model of the geometric extent of the hydrogeologic units at Yucca Mountain and is intended specifically for use in the development of the ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]). Primary inputs to this model report include the GFM 3.1 (DTN: MO9901MWDGFM31.000 [DIRS 103769]), borehole lithologic logs, geologic maps, geologic cross sections, water level data, topographic information, and geophysical data as discussed in Section 4.1. Figure 1-1 shows the information flow among all of the saturated zone (SZ) reports and the relationship of this conceptual model in that flow. The HFM-19 is a three-dimensional (3-D) representation of the hydrogeologic units surrounding the location of the Yucca Mountain geologic repository for spent nuclear fuel and high-level radioactive waste. The HFM-19 represents the hydrogeologic setting for the Yucca Mountain area that covers about 1,350 km2 and includes a saturated thickness of about 2.75 km. The boundaries of the conceptual model were primarily chosen to be coincident with grid cells in the Death Valley regional groundwater flow model (DTN: GS960808312144.003 [DIRS 105121]) such that the base of the site-scale SZ flow model is consistent with the base of the regional model (2,750 meters below a smoothed version of the potentiometric surface), encompasses the exploratory boreholes, and provides a framework over the area of interest for groundwater flow and radionuclide transport modeling. In depth, the model domain extends from land surface to the base of the regional groundwater flow model (D'Agnese et al. 1997 [DIRS 100131], p 2). For the site-scale SZ flow model, the HFM-19 is clipped, reducing the vertical extent to the interpreted top of the water table. The HFM-19 grid consists of a rectangular array of nodes with a spacing of 125 meters discussed in Sections 4.1, 5, and 6.3, and this selection simplifies the available data near the repository and extrapolates from very widely spaced data in other areas of the model domain. The HFM-19 is assembled by using geometric gridding techniques and software (described in Sections 3 and 6.3) to fill the domain area with 3-D elements corresponding to the 19 hydrogeologic units of interest. The HFM-19 is limited by simplifications that accommodate computer mapping, framework modeling, and modeling limitations and contains an inherent level of uncertainty that is a function of data distribution and geologic complexity. Uncertainty and limitations are discussed in Section 6.4 and model validation is discussed in Section 7. The HFM-19 provides the hydrogeologically defined internal geometry for SZ flow and transport process models, which was used to assign unit numbers to nodes in a mesh for use in site-scale SZ flow and transport models. The ''Saturated Zone Site-Scale Flow Model'' (BSC 2004 [DIRS 170037]) directly uses the output of this report to provide the spatial boundaries for each of the hydrogeologic units.
Download or read book Groundwater Flow and Thermal Modeling to Support a Preferred Conceptual Model for the Large Hydraulic Gradient North of Yucca Mountain written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study is to report on the results of a preliminary modeling framework to investigate the causes of the large hydraulic gradient north of Yucca Mountain. This study builds on the Saturated Zone Site-Scale Flow and Transport Model (referenced herein as the Site-scale model (Zyvoloski, 2004a), which is a three-dimensional saturated zone model of the Yucca Mountain area. Groundwater flow was simulated under natural conditions. The model framework and grid design describe the geologic layering and the calibration parameters describe the hydrogeology. The Site-scale model is calibrated to hydraulic heads, fluid temperature, and groundwater flowpaths. One area of interest in the Site-scale model represents the large hydraulic gradient north of Yucca Mountain. Nearby water levels suggest over 200 meters of hydraulic head difference in less than 1,000 meters horizontal distance. Given the geologic conceptual models defined by various hydrogeologic reports (Faunt, 2000, 2001; Zyvoloski, 2004b), no definitive explanation has been found for the cause of the large hydraulic gradient. Luckey et al. (1996) presents several possible explanations for the large hydraulic gradient as provided below: The gradient is simply the result of flow through the upper volcanic confining unit, which is nearly 300 meters thick near the large gradient. The gradient represents a semi-perched system in which flow in the upper and lower aquifers is predominantly horizontal, whereas flow in the upper confining unit would be predominantly vertical. The gradient represents a drain down a buried fault from the volcanic aquifers to the lower Carbonate Aquifer. The gradient represents a spillway in which a fault marks the effective northern limit of the lower volcanic aquifer. The large gradient results from the presence at depth of the Eleana Formation, a part of the Paleozoic upper confining unit, which overlies the lower Carbonate Aquifer in much of the Death Valley region. The Eleana Formation is absent at borehole UE-25 p#1 at Yucca Mountain, which penetrated the lower Carbonate Aquifer directly beneath the lower volcanic confining unit. The Site-scale model uses an area of very low permeability, referenced as the east-west barrier, to simulate the large hydraulic gradient. The Site-scale model is further refined in this study to provide a base-case model for exploring the geologic causes of the large hydraulic gradient.
Download or read book A New Saturated Zone Site scale Flow Model for Yucca Mountain written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Site Characterization Progress Report Yucca Mountain Nevada DOE RW 0498 April 1997 written by and published by . This book was released on 1997 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrology and Geochemistry of Yucca Mountain and Vicinity Southern Nevada and California written by John S. Stuckless and published by Geological Society of America. This book was released on 2012 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Site Scale Unsaturated Zone Transport Model of Yucca Mountain Rev 1 written by and published by . This book was released on 1997 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mineralogy of the unsaturated zone has an important bearing on the prediction of hydrologic and transport processes. The distribution of secondary minerals such as zeolites can strongly influence the flow patterns of percolating fluids through the unsaturated zone. The presence of other minerals such as smectite clays, may also be linked to, or evidence for, flow processes occurring in the unsaturated zone. The sorption of many radionuclides are also strongly controlled by the mineral distribution in the flow pathways between the repository and the water table. For these reasons, we have developed a streamlined method for incorporating mineralogic data directly into our site-scale model. The distribution of minerals has been organized into a numerical model using the STRATAMODEL software. An interface between the mineralogic model (reported by Chipera et al., 1997a, b) and the flow and transport simulation models developed in the present study has been developed to make the investigation of mineralogic controls on flow and transport as seamless as possible. In this milestone, the distribution of zeolites in the unsaturated zone is modeled using this information either through the assignment of a cut-off percentage above which the rock is given the properties of zeolitic tuff, or by populating the model with a zeolitic abundance that then is used in assigning flow and transport properties (Chapter 12). The mineralogic model incorporated into the simulations of the present study is an updated version of Chipera et al. (1997a).
Download or read book Status of Understanding of the Saturated zone Ground water Flow System at Yucca Mountain Nevada as of 1995 written by and published by . This book was released on 1996 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book OVERVIEW OF MODELING APPROACHES FOR ASSESSING NATURAL SYSTEM PERFORMANCE OF THE HIGH LEVEL RADIOACTIVE WASTE REPOSITORY AT YUCCA MOUNTAIN NEVADA written by M. Zhu and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For two decades, extensive hydrologic investigations have been conducted for geologic disposal of high-level radioactive waste in fractured volcanic tuffs at Yucca Mountain, Nevada. Extensive field and laboratory geologic, hydrologic, and geochemical testing has provided a large amount of data for developing the conceptual understanding of these processes and parameters for quantifying these processes. A suite of sophisticated numerical models has been developed to assess the long-term performance of the natural barrier of unsaturated zone (UZ) and saturated zone (SZ) to flow of groundwater and transport of radionuclides released from the repository. This work focuses on characterizing surface and subsurface processes of climate change, infiltration, percolation in the UZ and groundwater flow in the SZ, as well as on predicting hydrologic responses of the natural system to the emplacement of waste packages in drifts, including seepage of water into emplacement drifts and radionuclide transport in the UZ and SZ. These models are then abstracted into a total system performance assessment (TSPA) model. The TSPA integrates these natural attributes with features of engineered systems, and through systematic stochastic analyses involving Monte Carlo simulations, predicts the dose consequences and groundwater concentrations for at least 10,000 years for various future climate conditions, waste types, release scenarios, and transport pathways. The TSPA predictions demonstrate compliance with postclosure individual and groundwater protection standards in the license application for the repository. This presentation provides an overview of the development and use of these natural-system models, including the infiltration model, the site-scale UZ flow model, the seepage calibration and abstraction models, the UZ radionuclide transport and abstraction models, and the site-scale SZ flow and transport models. It describes the approaches used in the design and construct of these models, summarizes the tests and experiments conducted to obtain key input data, and discusses lessons learned in the efforts to validate the models and the treatment of uncertainties in the TSPA.
Download or read book Yucca Mountain Site Characterization Project Bibliography 1992 1993 written by and published by . This book was released on 1994 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Yucca Mountain Site Characterization Project Bibliography 1994 1995 written by and published by . This book was released on 1996 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geologic Repository for Disposal of Spent Nuclear Fuel and High level Radioactive Waste at Yucca Mountain written by and published by . This book was released on 1999 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
