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Detailed petrographic descriptions and microprobe data for tertiary silicic volcanic rocks in drill hole USW G-1, Yucca Mountain, Nevada

Description: This report contains detailed petrographic descriptions of 74 thin sections from drill hole USW G-1 at Yucca Mountain, Nevada. These descriptions are keyed to the distinctions between devitrified, vitrophyre, vitric, and zeolitized intervals below the Topopah Spring Member repository horizon. The petrographic features of the zeolitized intervals down through the Crater Flat tuff, as well as the sorption properties determined from these intervals, suggest that these zeolite occurrences may each have comparable sorptive capability.
Date: December 1, 1985
Creator: Caporuscio, F.A.; Warren, R.G. & Broxton, D.E.
Partner: UNT Libraries Government Documents Department

Fran Ridge horizontal coring summary report hole UE-25h No. 1, Yucca Mountain Area, Nye County, Nevada

Description: Hole UE-25h No. 1 was core drilled during December 1982 and January 1983 within several degrees of due west, 400 ft horizontally into the southeast slope of Fran Ridge at an altitude of 3409 ft. The purpose of the hole was to obtain data pertinent for radionuclide transport studies in the Topopah Spring Member of the Paintbrush Tuff. This unit had been selected previously as the host rock for the potential underground nuclear waste repository at Yucca Mountain, adjacent to the southwestern part of the Nevada Test Site. The hole was core drilled first with air, then with air mist, and finally with air, soap, and water. Many problems were encountered, including sloughing of tuff into the uncased hole, vibration of the drill rods, high rates of bit wear, and lost circulation of drilling fluids. On the basis of experience gained in drilling this hole, ways to improve horizontal coring with air are suggested in this report. All of the recovered core, except those pieces that were wrapped and waxed, were examined for lithophysal content, for fractures, and for fracture-fill mineralization. The results of this examination are given in this report. Core recovery greater than 80% at between 209 and 388 ft permitted a fracture frequency analysis. The results are similar to the fracture frequencies observed in densely welded nonlithophysal tuff from holes USW GU-3 and USW G-4. The fractures in core from UE-25h No. 1 were found to be smooth and nonmineralized or coated with calcite, silica, or manganese oxide. Open fractures with caliche (porous, nonsparry calcite) were not observed beyond 83.5 ft, which corresponds to an overburden depth of 30 ft.
Date: October 1, 1986
Creator: Norris, A.E.; Byers, F.M. Jr. & Merson, T.J.
Partner: UNT Libraries Government Documents Department

Borehole gravity meter survey in drill hole USW G-4, Yucca Mountain Area, Nye County, Nevada

Description: Drill hole USW G-4 was logged with the US Geological Survey borehole gravity meter (BHGM) BH-6 as part of a detailed study of the lithostratigraphic units penetrated by this hole. Because the BHGM measures a larger volume of rock than the conventional gamma-gamma density tool, it provides an independent and more accurate measurement of the in situ average bulk density of thick lithologic units. USW G-4 is an especially important hole because of its proximity to the proposed exploratory shaft at Yucca Mountain. The BHGM data were reduced to interval densities using a free-air gradient (F) of 0.3083 mGal./m (0.09397 mGal/ft) measured at the drill site. The interval densities were further improved by employing an instrument correction factor of 1.00226. This factor was determined from measurements obtained by taking gravity meter BH-6 over the Charleston Peak calibration loop. The interval density data reported herein, should be helpful for planning the construction of the proposed shaft.
Date: December 31, 1986
Creator: Healey, D.L.; Clutsom, F.G. & Glover, D.A.
Partner: UNT Libraries Government Documents Department

Petrochemical variation of Topopah Spring tuff matrix with depth (stratigraphic level), drill hole USW G-4, Yucca Mountain, Nevada

Description: This study describes and interprets petrochemical variation of the matrix (excluding fractures and large gas cavities) of the Topopah Spring Member of the Paintbrush Tuff. This tuff includes the candidate host rock for a high-level nuclear waste repository at Yucca Mountain on the Nevada Test Site. Cored hole USW G-4, near the site of a potential exploratory shaft at Yucca Mountain, penetrated 359.4 m (1179 ft) of the member within the unsaturated zone. This study shows that petrographic textures and chemistry of the matrix vary systematically within recognizable lithologic subunits related to crystallization (cooling) zones, welding (compaction) zones, and compositional zones (rhyolite versus quartz latite). The methods used for this study include petrographic modal thin section analysis using an automated counter and electron microprobe analysis of the groundmass. Distinctive textural categories are defined, and they can be ranked from finest to coarsest as vitrophyre (glass), cryptocrystalline groundmass, spherulites, granophyre, lithic fragments, and phenocrysts. The two main groundmass compositions are also defined: rhyolite high silica) and quartz latite. The value of these petrochemical studies lies in providing microscopic criteria for recognizing the zonal subunits where they may have greatly limited exposure, as in mined drifts and in core from horizontal drill holes. For example, the lower nonlithophysal zone can be distinguished microscopically from the middle nonlithophysal zone by (1) degree of compaction, (2) amount of quartz, and (3) amount of lithic fragments. The variability between these textural categories should also be considered in designing physical and chemical tests of the Topopah Spring.
Date: December 1, 1985
Creator: Byers, F.M. Jr.
Partner: UNT Libraries Government Documents Department

Isostatic uplift, crustal attenuation, and the evolution of an extensional detachment system in southwestern Nevada

Description: Geological and geophysical evidence supports the existence of extensional detachments, between the Sheep Range and Death Valley. It is proposed that geographically separated pieces of detachments between Death Valley and the Sheep Range are parts of a regional detachment system that has evolved since the Miocene, and that the system consists of lenses of strata separated by an anastomosing network of low- and high-angle normal faults. This manuscript emphasizes the probability that isostatic uplift within the region of greatest crustal attenuation in this system, the Bullfrog Hills core complex, controlled the evolution of the detachment system between the breakaway zone a the Sheep Range and the core complex. Features in this system are described from east to west, which is the apparent direction of tectonic transport.
Date: December 31, 1987
Creator: Scott, R.B.
Partner: UNT Libraries Government Documents Department

The quality assurance liaison: Combined technical and quality assurance support

Description: This paper describes the role of the quality assurance liaison, the responsibilities of this position, and the evolutionary changes in duties over the last six years. The role of the quality assurance liaison has had a very positive impact on the Los Alamos Yucca Mountain Site Characterization (YW) quality assurance program. Having both technical and quality assurance expertise, the quality assurance liaisons are able to facilitate communications with scientists on quality assurance issues and requirements, thereby generating greater productivity in scientific investigations. The quality assurance liaisons help ensure that the scientific community knows and implements existing requirements, is aware of new or changing regulations, and is able to conduct scientific work within Project requirements. The influence of the role of the quality assurance liaison can be measured by an overall improvement in attitude of the staff regarding quality assurance requirements and improved job performance, as well as a decrease in deficiencies identified during both internal and external audits and surveillances. This has resulted in a more effective implementation of quality assurance requirements.
Date: March 1, 1993
Creator: Bolivar, S.L. & Day, J.L.
Partner: UNT Libraries Government Documents Department

Inverse modeling as a step in the calibration of the LBL-USGS site-scale model of Yucca Mountain

Description: Calibration of the LBL-USGS site-scale model of Yucca Mountain is initiated. Inverse modeling techniques are used to match the results of simplified submodels to the observed pressure, saturation, and temperature data. Hydrologic and thermal parameters are determined and compared to the values obtained from laboratory measurements and conventional field test analysis.
Date: May 1, 1995
Creator: Finsterle, S.; Bodvarsson, G.S. & Chen, G.
Partner: UNT Libraries Government Documents Department

1992-93 Results of geomorphological and field studies Volcanic Studies Program, Yucca Mountain Project

Description: Field mapping and stratigraphic studies were completed of the Black Tank volcanic center, which represents the southwestern most eruptive center in the Cima volcanic field of California. The results of this mapping are presented. Contacts between volcanic units and geomorphic features were field checked, incorporating data from eight field trenches as well as several exposures along Black Tank Wash. Within each of the eight trenches, logs were measured and stratigraphic sections were described. These data indicate that three, temporally separate volcanic eruptions occurred at the Black Tank center. The field evidence for significant time breaks between each stratigraphic unit is the presence of soil and pavement-bounded unconformities.
Date: October 1, 1993
Creator: Wells, S.G.
Partner: UNT Libraries Government Documents Department

Selected ground-water data for Yucca Mountain Region, Southern Nevada and Eastern California, Calendar year 1993

Description: Data are collected to allow assessments of ground-water resources during studies to determine the potential suitability of Yucca Mountain for storing high-level nuclear waste. Data on ground-water levels at 34 sites, ground-water discharge at 6 sites, and groundwater withdrawals within Jackass Flats, Mercury Valley, and Amargosa Desert are presented for calendar year 1993. Data on ground-water levels, discharges, and withdrawals collected by other agencies (or as part of other programs) are included to further indicate variations through time at selected monitoring locations. A statistical summary of ground-water levels at seven wells in Jackass Flats is presented. The statistical summary includes the number of measurements, the maximum, minimum, and median or mean water-level altitudes, and the average or standard deviation of the water-level altitudes for selected baseline periods and for calendar years 1992 and 1993.
Date: July 1, 1995
Creator: Hale, G.S. & Westenburg, C.L.
Partner: UNT Libraries Government Documents Department

Creep in Topopah Spring Member welded tuff. Yucca Mountain Site Characterization Project

Description: A laboratory investigation has been carried out to determine the effects of elevated temperature and stress on the creep deformation of welded tuffs recovered from Busted Butte in the vicinity of Yucca Mountain, Nevada. Water saturated specimens of tuff from thermal/mechanical unit TSw2 were tested in creep at a confining pressure of 5.0 MPa, a pore pressure of 4.5 MPa, and temperatures of 25 and 250 C. At each stress level the load was held constant for a minimum of 2.5 {times} 10{sup 5} seconds and for as long as 1.8 {times} 10{sup 6} seconds. One specimen was tested at a single stress of 80 MPa and a temperature of 250 C. The sample failed after a short time. Subsequent experiments were initiated with an initial differential stress of 50 or 60 MPa; the stress was then increased in 10 MPa increments until failure. The data showed that creep deformation occurred in the form of time-dependent axial and radial strains, particularly beyond 90% of the unconfined, quasi-static fracture strength. There was little dilatancy associated with the deformation of the welded tuff at stresses below 90% of the fracture strength. Insufficient data have been collected in this preliminary study to determine the relationship between temperature, stress, creep deformation to failure, and total failure time at a fixed creep stress.
Date: June 1, 1995
Creator: Martin, R.J. III; Boyd, P.J.; Noel, J.S. & Price, R.H.
Partner: UNT Libraries Government Documents Department

Lithostratigraphy of the Calico Hills Formation and Prow Pass Tuff (Crater Flat Group) at Yucca Mountain, Nevada

Description: Lithostratigraphic relations within the Calico Hills Formation and Prow Pass Tuff (Crater Flat Group) were reconstructed from analysis of core samples and observation of outcrop exposures. The Calico Hills Formation is composed of five nonwelded pyroclastic units (each formed of one or more pyroclastic-flow deposits) that overlie an interval of bedded tuff and a basal volcaniclastic sandstone unit. The Prow Pass Tuff is divided into four pyroclastic units and an underlying interval of bedded tuff. The pyroclastic units of the Prow Pass Tuff are distinguished by the sizes and amounts of their pumice and lithic clasts and their degree of welding. Pyroclastic units of the Prow Pass Tuff are distinguished from those of the Calico Hills Formation by their phenocryst assemblage, chemical composition, and ubiquitous siltstone lithic clasts. Downhole resistivity tends to mirror the content of authigenic minerals, primarily zeolites, in both for-mations and may be useful for recognizing the vitric-zeolite boundary in the study area. Maps of zeolite distribution illustrate that the bedded tuff and basal sandstone units of the Calico Hills Formation are altered over a wider area than the pyroclastic units of both the Calico Hills Formation and the upper Prow Pass Tuff.
Date: July 1, 1995
Creator: Moyer, T.C. & Geslin, J.K.
Partner: UNT Libraries Government Documents Department

Ground Water Level Measurements in Selected Boreholes Near the Site of the Proposed Repository

Description: The Harry Reid Center for Environmental Studies (HRC) at the University of Nevada, Las Vegas (UNLV) acquired quarterly and continuous data on water levels from approximately 26 boreholes that comprise a periodic monitoring network (Table 1) between October 2003 and September 2007. During this period we continued to observe and analyze short and long-term ground water level trends in periodically monitored boreholes. In this report we summarize and discuss four key findings derived from analysis of water level data acquired during this period: 1. Rapid ground water level rise after storm events in Forty Mile Canyon; 2. Seismically-induced ground water level fluctuations; 3. A sample of synoptic observations and barometric influences on short term fluctuations; and 4. Long term ground water level trends observed from mid-2001 through late-2005.
Date: November 29, 2007
Creator: Page, H. Scott
Partner: UNT Libraries Government Documents Department

Seismicity in the Vicinity of Yucca Mountain, Nevada, for the Period October 1, 2002, to September 30, 2003

Description: Earthquake activity in the Yucca Mountain from October 1, 2002 through September 30, 2003 (FY03) is assessed and compared with previous activity in the region. FY03 is the first reporting year since the 1992 M 5.6 Little Skull Mountain earthquake with no earthquakes greater than M 3.0 within 65 km of Yucca Mountain. In addition, FY03 includes the fewest number of earthquakes greater than M 2.0 in any reporting year since the LSM event. With 3075 earthquakes in the catalog, FY03 represents the second largest number of earthquakes (second to FY02) since FY96 when digital seismic network operations began. The largest event during FY03 was M 2.78 in eastern NTS and there were only 8 earthquakes greater than M 2.0.
Date: December 4, 2007
Creator: Smith, Ken & von Seggern, David
Partner: UNT Libraries Government Documents Department

Modeling coupled thermal-hydrological-chemical processes in theunsaturated fractured rock of Yucca Mountain, Nevada: Heterogeneity andseepage

Description: An understanding of processes affecting seepage intoemplacement tunnels is needed for correctly predicting the performance ofunderground radioactive waste repositories. It has been previouslyestimated that the capillary and vaporization barriers in the unsaturatedfractured rock of Yucca Mountain are enough to prevent seepage underpresent day infiltration conditions. It has also been thought that asubstantially elevated infiltration flux will be required to causeseepage after the thermal period is over. While coupledthermal-hydrological-chemical (THC) changes in Yucca Mountain host rockdue to repository heating has been previously investigated, those THCmodels did not incorporate elements of the seepage model. In this paper,we combine the THC processes in unsaturated fractured rock with theprocesses affecting seepage. We observe that the THC processes alter thehydrological properties of the fractured rock through mineralprecipitation and dissolution. We show that such alteration in thehydrological properties of the rock often leads to local flow channeling.We conclude that such local flow channeling may result in seepage undercertain conditions, even with nonelevated infiltrationfluxes.
Date: July 15, 2005
Creator: Mukhopadhyay, Sumit; Sonnenthal, Eric L. & Spycher, Nicolas
Partner: UNT Libraries Government Documents Department

Estimating large-scale fracture permeability of unsaturatedrockusing barometric pressure data

Description: We present a three-dimensional modeling study of gas flow inthe unsaturated fractured rock of Yucca Mountain. Our objective is toestimate large-scale fracture permeability, using the changes insubsurface pneumatic pressure in response to barometric pressure changesat the land surface. We incorporate the field-measured pneumatic datainto a multiphase flow model for describing the coupled processes ofliquid and gas flow under ambient geothermal conditions. Comparison offield-measured pneumatic data with model-predicted gas pressures is foundto be a powerful technique for estimating the fracture permeability ofthe unsaturated fractured rock, which is otherwise extremely difficult todetermine on the large scales of interest. In addition, this studydemonstrates that the multi-dimensional-flow effect on estimatedpermeability values is significant and should be included whendetermining fracture permeability in heterogeneous fracturedmedia.
Date: May 17, 2005
Creator: Wu, Yu-Shu; Zhang, Keni & Liu, Hui-Hai
Partner: UNT Libraries Government Documents Department

Calculation of drift seepage for alternative emplacementdesigns

Description: The calculations presented in this report are performed to obtain seepage rates into drift and boreholes for two alternative designs of drift and waste emplacement at Yucca Mountain. The two designs are defined according to the Scope of Work 14012021M1, activity 399621, drafted October 6, 1998, and further refined in a conference telephone call on October 13, 1998, between Mark Balady, Jim Blink, Rob Howard and Chin-Fu Tsang. The 2 designs considered are: (1) Design A--Horizontal boreholes 1.0 m in diameter on both sides of the drift, with each borehole 8 m long and inclined to the drift axis by 30 degrees. The pillar between boreholes, measured parallel to the drift axis, is 3.3 m. In the current calculations, a simplified model of an isolated horizontal borehole 8 m long will be simulated. The horizontal borehole will be located in a heterogeneous fracture continuum representing the repository layer. Three different realizations will be taken from the heterogeneous field, representing three different locations in the rock. Seepage for each realization is calculated as a function of the percolation flux. Design B--Vertical boreholes, 1.0 m in diameter and 8.0 m deep, drilled from the bottom of an excavated 8.0 m diameter drift. Again, the drift with the vertical borehole will be assumed to be located in a heterogeneous fracture continuum, representing the rock at the repository horizon. Two realizations are considered, and seepage is calculated for the 8-m drift with and without the vertical 1-m borehole at its bottom.
Date: July 30, 1999
Creator: Li, Guomin; Tsang, Chin-Fu & Birkholzer, Jens
Partner: UNT Libraries Government Documents Department

Final predictions of ambient conditions along the east-west crossdrift using the 3-D UZ site-scale model. Level 4 milestoneSP33ABM4.

Description: In 1998, the Yucca Mountain Site Characterization Project (YMP) is expected to continue construction of an East-West Cross Drift. The 5-meter diameter drift will extend from the North Ramp of the Exploratory Studies Facility (ESF), near Station 19+92, southwest through the repository block, and over to and through the Solitario Canyon Fault. This drift is part of a program designed to enhance characterization of Yucca Mountain and to complement existing surface-based and ESF testing studies. The objective of this milestone is to use the three-dimensional (3-D) unsaturated zone (UZ) site-scale model to predict ambient conditions along the East-West Cross Drift. These predictions provide scientists and engineers with a priori information that can support design and construction of the East-West Cross Drift and associated testing program. The predictions also provide, when compared with data collected after drift construction, an opportunity to test and verify the calibration of the 3-D UZ site-scale model.
Date: March 1, 1998
Creator: Ritcey, A.C.; Sonnenthal, E.L.; Wu, Y.S.; Haukwa, C. & Bodvarsson,G.S.
Partner: UNT Libraries Government Documents Department

Civilian Nuclear Waste Disposal

Description: This report discusses disposal of nuclear waste, primarily highly radioactive spent fuel from nuclear power plants. Presidential and Congressional actions regarding nuclear waste disposal sites and the Yucca Mountain Project, other alternatives previously proposed by the Obama Administration, and temporary solutions are discussed.
Date: October 23, 2017
Creator: Holt, Mark
Partner: UNT Libraries Government Documents Department

Coupled THM analysis of the single-heater test at yucca mountain

Description: This paper presents a summary of results from the Single-Heater Test (SHT) at Yucca Mountain, Nevada. In the SHT, a horizontal, 5-m-long, line-heat source was used to heat a rock pillar for nine months. Moisture movement was monitored during and after heating using electrical-resistance tomography (ERT) and neutron-logging techniques. Results indicate drying in regions of the rock where temperature reached 60°C and above. The drying zone is asymmetric and is not centered on the heater, but has lobes extending above and to the sides of the heater. Predicted temperatures agreed well with observations. A cold- trap effect was predicted, in the heater borehole, that efficiently transfers heat along the heater borehole to the excavation wall. A simple thermomechanical analysis of the SHT shows that shear zones predicted for vertical fractures coincide with regions of increased moisture content derived from ERT measurements.
Date: January 25, 1999
Creator: Blair, S. C.; Buscheck, T. A.; Daily, W. D.; Lin, W. & Ramirez, A. L.
Partner: UNT Libraries Government Documents Department

Geochemical alteration of backfill FY98 status report

Description: The Yucca Mountain Project is considering some type of backfill, possibly emplaced as a capillary barrier, for inclusion in the Engineering Barrier System (EBS) at the potential Yucca Mountain nuclear waste repository site. The performance of capillary barriers in isothermal, low- temperature, environments has been studied extensively (e.g., Ho and Webb, 1998; OZdenburg and Pruess, 1993; Ross, 1990). The performance of capillary barriers in an non-isothermal, high temperature environment, such as during the thermal pulse phase of a nuclear waste repository, has received much less attention. One concern is that the backfill materials may be altered from that of the as-placed material by the hydrothermal regime imposed by the emplacement of waste in the repository, changing hydrologic properties in a way that degrades the performance of the EBS system. This report is a status report on our efforts to address this concern. The work was initiated by SCR #98-76-041 and was authorized to begin at LLNL in summer 1998. This report is organized as follows. In the first part, we discuss our understanding of the relevant issues of backfill performance based on thermal hydrology. We focus here on changes to hydrologic properties, but we recognize that changes to thermal, mechanical and chemical (e.g., sorptive) properties are also important. Our primary interest is in addressing concerns over possible changes in the magnitude of key hydrologic properties (i.e., porosity, permeability, and moisture retention characteristics) that could significantly affect the design performance of backfill in the EBS. We report on what we know from previous work about geochemical alteration of backfill material, focusing primarily on crushed tuff. In the second part of this report, we present our progress on geochemical studies on backfill materials. These include sub-boiling, two-phase column experiments, batch experiments at above boiling temperatures and associated numerical modeling.
Date: September 30, 1998
Creator: Buscheck, T.; Knauss, K.; Rosenberg, N. & Viani, B.
Partner: UNT Libraries Government Documents Department

Thermodynamics of calcium silicate hydrates, development of a database to model concrete dissolution at 25°C using the EQ3/6 geochemical modeling code

Description: Examination of the ability to model aqueous systems of interest to the repository proposed by the Yucca Mountain Project has revealed an historical deficit in the ability to model complex waterÐmaterial systems that contain ordinary Portland cement (OPC) at elevated temperature (e.g., Bruton et al., 1994; Meike et al., 1994). One of the reasons is that cement chemistry typically concentrates on two issues of importance to the concrete industry: the hydration of cement powder, which contains reactive phases that do not persist in the cured concrete, and the causes of mechanical degradation at earth surface temperatures such as delayed ettringite formation and alkali silica reaction. Such modeling capability is not available in the open literature, even from applications that might have developed high temperature approaches, such as deep drilling for oil and geothermal resource recovery. The ability to simulate the interaction between concrete, as it evolves over time, and water has become more critical as repository designers begin to consider the incorporation of OPC materials in the emplacement drifts. The Yucca Mountain Project is unique among the high-level radioactive waste repository projects in the world in terms of the need to understand and predict processes in excess of 100°C (see, e.g., Meike, 1997). Our aim has been to develop this capability in the area of aqueous chemistry.
Date: August 18, 1997
Creator: Clodic, L. & Meike, A.
Partner: UNT Libraries Government Documents Department

Electrical resistance tomography of unsaturated flow and transport in Yucca Mountain

Description: Electrical Resistance Tomography (ERT), a new geophysical imaging technique, was used to study the movement of a tracer through the test block at the Unsaturated Zone Transport Test (UZTT) at Busted Butte, Nevada. Data were collected four times starting in July and ending in early September, 1998. ERT baseline images show a resistivity structure which is consistent with the known lithology in the rear part of the test block. There appears to be a low resistivity region in the front half of the block, particularly near the bottom. Difference images from August 19 and September 9 show clear and consistent resistivity decreases in the region near injection holes 18, 20, and 21 which can be associated with the injection of conductive water. The images show very little effect in the region around the other injection holes, 23, and 24 through 27 where far less water was injected. Difference images from August 19 and September 9 show resistivity decreases which could be interpreted as water moving down into the block. This is the same region which has an anomalously low resistivity in the baseline image. These results should be considered preliminary, and are subject to further interpretation.
Date: December 28, 1998
Creator: Buettner, H M; Bussod, G; Daily, W & Ramirez, A
Partner: UNT Libraries Government Documents Department

Application of software quality assurance to a specific scientific code development task

Description: This paper describes an application of software quality assurance to a specific scientific code development program. The software quality assurance program consists of three major components: administrative control, configuration management, and user documentation. The program attempts to be consistent with existing local traditions of scientific code development while at the same time providing a controlled process of development.
Date: March 1, 1986
Creator: Dronkers, J.J.
Partner: UNT Libraries Government Documents Department