Download or read book Use of Chlorine 36 and Other Geochemical Data to Test a Groundwater Flow Model for Yucca Mountain Nevada written by and published by . This book was released on 1998 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: Defining the spatial distribution and timing of subsurface fluid percolation is one of the most important factors determining long term performance of the potential high-level radioactive waste repository at Yucca Mountain, Nevada. The nonwelded interval of the Paintbrush Group (PTn), which overlies most of the potential repository, has high matrix porosities and permeabilities and is mostly unfractured. The Exploratory Studies Facility (ESF) is a 8-km long, 7.6-m diameter, tunnel excavated beneath Yucca Mountain to the level of the potential repository horizon in order to provide access for characterization of these rocks. Several samples collected within the ESF have measured 36Cl/Cl ratios that record anthropogenic 36Cl (bomb-pulse 36Cl), indicating that at least some fraction of the water has traversed the overlying PTn in 40 years or less and that flow is not confined to the matrix of that unit. The presence of a fast path transmitting bomb-pulse 36Cl to depth appears to require the simultaneous presence of a structure (such as a fault) cutting the PTn and sufficiently high magnitude to surface infiltration to initiate and sustain at least a small component of fracture flow along the connected fracture path associated with the structure. The 36Cl data have been simulated using the flow and transport model FEHM in order to establish bounds on infiltration rates at the site and to provide greater confidence in the understanding of unsaturated flow processes at the site by showing consistency between the observed and simulated data sets. An analogous effort simulating the distribution of porewater chloride concentrations is providing an independent means for confirming the conceptual model.
Download or read book Modelling the Effects of Spatial Variability on Radionuclide Migration written by and published by Organisation for Economic Co-operation and Development. This book was released on 1998 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite element Simulation of Ground water Flow in the Vicinity of Yucca Mountain Nevada California written by John B. Czarnecki and published by . This book was released on 1985 with total page 50 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 The Relationship of the Yucca Mountain Repository Block to the Regional Ground water System written by and published by . This book was released on 1989 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yucca Mountain, in southern Nevada, is being studied by the Department of Energy and the State of Nevada as the site of a high-level nuclear waste repository. Geochemical and isotopic modeling were used in this study to define the relationship of the volcanic tuff aquifers and aquitards to the underlying regional carbonate ground-water system. The chemical evolution of a ground water as it passes through a hypothetical tuffaceous aquifer was developed using computer models PHREEQE, WATEQDR and BALANCE. The tuffaceous system was divided into five parts, with specific mineralogies, reaction steps and temperatures. The initial solution was an analysis of a soil water from Rainier Mesa. The ending solution in each part became the initial solution in the next part. Minerals consisted of zeolites, smectites, authigenic feldspars and quartz polymorphs from described diagentic mineral zones. Reaction steps were ion exchange with zeolites. The solution from the final zone, Part V, was chosen as most representative, in terms of pH, element molalities and mineral solubilities, of tuffaceous water. This hypothetical volcanic water from Part V was mixed with water from the regional carbonate aquifer, and the results compared to analyses of Yucca Mountain wells. Mixing and modeling attempts were conducted on wells in which studies indicated upward flow.
Download or read book Hydrogeochemical Feasibility Studies Related to Subsurface Flow on Yucca Mountain Nevada Test Site written by Gregory S. Davis and published by . This book was released on 1985 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Three Dimensional Numerical Model of Predevelopment Conditions in the Death Valley Regional Ground Water Flow System Nevada and California written by and published by DIANE Publishing. This book was released on with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Carbon 14 Calibrated Discrete state Compartment Model of the Groundwater Flow System Yucca Mountain and Vicinity Nevada California written by Robert Martin Byer and published by . This book was released on 1991 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrochemical Investigations in Characterizing the Unsaturated Zone at Yucca Mountain Nevada written by and published by . This book was released on 1998 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrochemical and isotopic investigations of ground water at Yucca Mountain, Nevada, site of a potential permanent national nuclear-waste repository, demonstrate that younger rocks are dominated by calcium-sulfate or calcium-chloride water and that older rocks contain sodium-carbonate or sodium-bicarbonate water. Furthermore, unsaturated-zone pore water has significantly larger concentrations of major ions and dissolved solids than does the saturated-zone water. Recharge of perched or saturated-zone water, therefore, requires rapid flow through fractures or permeable regions in the unsaturated zone to avoid mixing with the chemically concentrated water in the unsaturated zone. This conceptual model is consistent with observations of rapidly moved post-bomb (post-1954) tritium and chlorine-36 in the deep unsaturated zone at Yucca Mountain. Presence of post-bomb tritium in matrix water away from fracture zones further indicates that parts of the fast-flow water that moves through fractures have been diverted laterally into nonwelded units. Experimental data show that different lithologic units require specific water-extraction methods for stable-isotope analyses of hydrogen and oxygen to ensure accurate characterization. Vacuum-distillation and compression-extraction methods both can yield accurate data but must be used with specific lithologies. Column experiments demonstrate that percolating water can exchange with pore water of the core as well as water held in zeolite minerals in the core. Exchange rates range from days to months. Pore-water samples from core, therefore, reflect the most recently infiltrated water but do not reflect percolating water of the distant past.
Download or read book In Situ Production of Chlorine 36 in the Eastern Snake River Plain Aquifer Idaho written by and published by . This book was released on 2000 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sensitivity Studies of Unsaturated Groundwater Flow Modeling for Groundwater Travel Time Calculations at Yucca Mountain Nevada written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three dimensional Numerical Modeling of the Influence of Faults on Groundwater Flow at Yucca Mountain Nevada written by Andrew J.B. Cohen and published by . This book was released on 1999 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical simulations of groundwater flow at Yucca Mountain, Nevada are used to investigate how the faulted hydrogeologic structure influences groundwater flow from a proposed high-level nuclear waste repository. Simulations are performed using a 3-D model that has a unique grid block discretization to accurately represent the faulted geologic units, which have variable thicknesses and orientations. Irregular grid blocks enable explicit representation of these features. Each hydrogeologic layer is discretized into a single layer of irregular and dipping grid blocks, and faults are discretized such that they are laterally continuous and displacement varies along strike. In addition, the presence of altered fault zones is explicitly modeled, as appropriate. The model has 23 layers and 11 faults, and approximately 57,000 grid blocks and 200,000 grid block connections. In the past, field measurement of upward vertical head gradients and high water table temperatures near faults were interpreted as indicators of upwelling from a deep carbonate aquifer. Simulations show, however, that these features can be readily explained by the geometry of hydrogeologic layers, the variability of layer permeabilities and thermal conductivities, and by the presence of permeable fault zones or faults with displacement only. In addition, a moderate water table gradient can result from fault displacement or a laterally continuous low permeability fault zone, but not from a high permeability fault zone, as others postulated earlier. Large-scale macrodispersion results from the vertical and lateral diversion of flow near the contact of high and low permeability layers at faults, and from upward flow within high permeability fault zones. Conversely, large-scale channeling can occur due to groundwater flow into areas with minimal fault displacement. Contaminants originating at the water table can flow in a direction significantly different than that of the water table gradient, and isolated zones of contaminants will occur at the water table downgradient. This behavior is not predicted by traditional models of contaminant transport. In addition, the influence of a particular type of fault cannot be generalized; depending on the location where contaminants enter the saturated zone, faults may either enhance or inhibit vertical dispersion.
Download or read book Three dimensional Numerical Modeling of the Influence of Faults on Groundwater Flow at Yucca Mountain Nevada written by and published by . This book was released on 1999 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical simulations of groundwater flow at Yucca Mountain, Nevada are used to investigate how the faulted hydrogeologic structure influences groundwater flow from a proposed high-level nuclear waste repository. Simulations are performed using a 3-D model that has a unique grid block discretization to accurately represent the faulted geologic units, which have variable thicknesses and orientations. Irregular grid blocks enable explicit representation of these features. Each hydrogeologic layer is discretized into a single layer of irregular and dipping grid blocks, and faults are discretized such that they are laterally continuous and displacement varies along strike. In addition, the presence of altered fault zones is explicitly modeled, as appropriate. The model has 23 layers and 11 faults, and approximately 57,000 grid blocks and 200,000 grid block connections. In the past, field measurement of upward vertical head gradients and high water table temperatures near faults were interpreted as indicators of upwelling from a deep carbonate aquifer. Simulations show, however, that these features can be readily explained by the geometry of hydrogeologic layers, the variability of layer permeabilities and thermal conductivities, and by the presence of permeable fault zones or faults with displacement only. In addition, a moderate water table gradient can result from fault displacement or a laterally continuous low permeability fault zone, but not from a high permeability fault zone, as others postulated earlier. Large-scale macrodispersion results from the vertical and lateral diversion of flow near the contact of high and low permeability layers at faults, and from upward flow within high permeability fault zones. Conversely, large-scale channeling can occur due to groundwater flow into areas with minimal fault displacement. Contaminants originating at the water table can flow in a direction significantly different than that of the water table gradient, and isolated zones of contaminants will occur at the water table downgradient. This behavior is not predicted by traditional models of contaminant transport. In addition, the influence of a particular type of fault cannot be generalized; depending on the location where contaminants enter the saturated zone, faults may either enhance of inhibit vertical dispersion.
Download or read book Determination of Water Movement in the Unsaturated Zone at Yucca Mountain Using Chloride Bromide and Chlorine Isotopes as Environmental Tracers Final Report written by and published by . This book was released on 1994 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report, prepared by Hydro Geo Chem staff for Los Alamos National Laboratory, summarizes work conducted by the company under Subcontract 9-XG1-N3993-1. The ultimate objective of this work is to characterize the movement of subsurface water in the vicinity of Yucca Mountain, Nevada. Data produced under this contract is to be used by the US Department of Energy in its Yucca Mountain Site Characterization Project (YMP) to help determine hydrologic flows that may affect the performance of a potential nuclear waste repository. The data may be used in the licensing proceedings, and certain quality assurance procedures have thus been required. The work has focussed on measuring the distribution of environmental tracers-chlorine-36, chlorine, and bromine-and on evaluating the depth to which these conservative solutes have percolated in the unsaturated zone at Yucca Mountain. The following discussion summarizes progress made on the tasks outlined in the original Scope of Work. Details of this work and all data acquired by Hydro Geo Chem for this subcontract have been systematically organized in logbooks and laboratory notebooks. These documents have been structured to make it easy to trace the analytical history of a sample, from time of receipt to the final analytical results.
Download or read book Environmental Tracers written by Trevor Elliot and published by MDPI. This book was released on 2018-10-08 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Environmental Tracers" that was published in Water
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:
