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Use of an ultrasonic/sonic driller/corer to obtain sample powder for chemin, a combined XRD/XRF instrument.

Description: One of the technical issues that must be addressed before landing an XRD,iXRF spectrometer on an extraterrestrial body is how best to obtain a representative sample powder for analysis. For XRD powder diffraction analyses, it is beneficial to have a powder that is extremely fine grained to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the Xray beam. Although a 2 dimensional detector as used in the CHEMIN instrument will produce good re… more
Date: January 1, 2003
Creator: Chipera, S. J. (Steve J.); Bish, D. L. (David L.); Vaniman, D. T. (David T.); Sherrit, S.; Bar-Cohen, Yoseph & Blake, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Miniature CVD-diamond corning drills for robotic sample collection and analysis.

Description: Coring tools have been used etlectivelv on the Moon, but to date no such tools have been used on any other extraterrestrial surface. The lunar experience includes both manual (Apollo) and robotic (Luna) systems . These coring systems were concerned primarily with acquiring samples from depth for return to Earth or for the creation of instrument emplacement holes (e .g ., heat probes). Current designs for planetary drills differ from the lunar tools primarily in that they are integrated with rob… more
Date: January 1, 2003
Creator: Vaniman, D. T. (David T.); Trava-Airoldi, V.J.; Bish, D. L. (David L.) & Chipera, S. J. (Steve J.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Uranium and Neptunium Desorption from Yucca Mountain Alluvium

Description: Uranium and neptunium were used as reactive tracers in long-term laboratory desorption studies using saturated alluvium collected from south of Yucca Mountain, Nevada. The objective of these long-term experiments is to make detailed observations of the desorption behavior of uranium and neptunium to provide Yucca Mountain with technical bases for a more realistic and potentially less conservative approach to predicting the transport of adsorbing radionuclides in the saturated alluvium. This pap… more
Date: March 16, 2006
Creator: Scism, C. D.; Reimus, P. W.; Ding, M. & Chipera, S. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mineralogical Charecteristics of Yucca Mountain Alluvium and Effects on Neptunium (V) Sorption

Description: Saturated alluvium is expected to serve as an important natural barrier to radionuclide transport at Yucca Mountain, the proposed geological repository for disposal of high-level nuclear wastes. {sup 237}Np(V) (half-life = 2.4 x 10{sup 5} years) has been identified as one of the radionuclides that could potentially contribute the greatest dose to humans because of its relatively high solubility and weak adsorption to volcanic tuffs under oxidizing conditions. The previous studies suggested that… more
Date: September 5, 2006
Creator: Ding, M.; Chipera, S. J. & Reimus, P. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Uranium-Series Constraints on Subrepository Water Flow at Yucca Mountain, Nevada

Description: Mineral abundances and whole-rock chemical and uranium-series isotopic compositions were measured in unfractured and rubble core samples from borehole USWSD-9 in the same layers of variably zeolitized tuffs that underlie the proposed nuclear waste repository at Yucca Mountain, Nevada. Uranium concentrations and isotopic compositions also were measured in pore water from core samples from the same rock units and rock leachates representing loosely bound U adsorbed on mineral surfaces or containe… more
Date: March 10, 2006
Creator: Neymark, L. A.; Paces, J. B.; Chipera, S. J. & Vaniman, D. T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Silica Deposition in Field and Laboratory Thermal Tests of Yucca Mountain Tuff

Description: A field thermal test was conducted by the Yucca Mountain Site Characterization Project to observe changes in the Topopah Spring Tuff middle nonlithophysal zone geohydrologic system due to thermal loading. A laboratory-scale crushed-tuff hydrothermal column test was used to investigate the tuff as a potential construction material within a nuclear-waste repository. Results of similar column tests have been cited as indications that silica deposition would plug the rock fractures above a reposito… more
Date: August 30, 2002
Creator: Levy, S. S.; Chipera, S. J. & Snow, M. G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Distribution of potentially hazardous phases in the subsurface at Yucca Mountain, Nevada

Description: Drilling, trenching, excavation of the Exploratory Studies Facility, and other surface and underground-distributing activities have the potential to release minerals into the environment from tuffs at Yucca Mountain, Nevada. Some of these minerals may be potential respiratory health hazards. Therefore, an understanding of the distribution of the minerals that may potentially be liberated during site-characterization and operation of the potential repository is crucial to ensuring worker and pub… more
Date: May 1, 1995
Creator: Guthrie Jr., G. D.; Bish, D. L.; Chipera, S. J. & Raymond Jr., R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mineralogy of drill holes J-13, UE-25A No. 1, and USW G-1 at Yucca Mountain, Nevada

Description: The mineralogy of drill holes J-13, UE-25A No. 1, and USW G-1 was previously determined using qualitative and semiquantitative techniques, and most of the available data were neither complete nor accurate. New quantitative x-ray diffraction data were obtained for rocks from all three of these drill holes at Yucca Mountain, Nevada. These quantitative analyses employed both external and internal standard x-ray powder diffraction methods and permitted the precise determination of all phases common… more
Date: September 1, 1986
Creator: Bish, D. L. & Chipera, S. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Thermodynamic modeling of natural zeolite stability

Description: Zeolites occur in a variety of geologic environments and are used in numerous agricultural, commercial, and environmental applications. It is desirable to understand their stability both to predict future stability and to evaluate the geochemical conditions resulting in their formation. The use of estimated thermodynamic data for measured zeolite compositions allows thermodynamic modeling of stability relationships among zeolites in different geologic environments (diagenetic, saline and alkali… more
Date: June 1, 1997
Creator: Chipera, S. J. & Bish, D. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Mineralogy of drill hole UE-25p#1 at Yucca Mountain, Nevada

Description: Drill hole UE-25p{number_sign}1 is located east of the candidate repository block at Yucca Mountain, Nevada, and as such provides information on the geology of the accessible environment. The hole was drilled to a depth of 1807 m (5923 ft) and is unique in that it penetrates tuffs that are older than any volcanic units previously encountered in drill holes at Yucca Mountain. In addition, it is the only hole drilled to date that penetrates the base of the tuff sequence and enters the underlying … more
Date: May 1, 1988
Creator: Chipera, S. J. & Bish, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Revised mineralogic summary of Yucca Mountain, Nevada

Description: We have evaluated three-dimensional mineral distribution at Yucca Mountain, Nevada, using quantitative x-ray powder diffraction analysis. All data were obtained on core cuttings, or sidewall samples obtained from drill holes at and around Yucca Mountain. Previously published data are included with corrections, together with new data for several drill holes. The new data presented in this report used the internal standard method of quantitative analysis, which yields results of high precision fo… more
Date: March 1, 1989
Creator: Bish, D. L. & Chipera, S. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mineralogic variation in drill holes USW NRG-6, NRG-7/7a, SD-7, SD-9, SD-12, and UZ{number_sign}14: New data from 1996--1997 analyses

Description: New quantitative X-ray diffraction (QXRD) mineralogic data have been obtained for samples from drill holes NRG-6, NRG-7/7A, SD-7, SD-9, SD- 12, and UZ{number_sign}14. In addition, new QXRD analyses were obtained on samples located in a strategic portion of drill hole USW H-3. These data improve our understanding of the mineral stratigraphy at Yucca Mountain, and they further constrain the 3-D Mineralogic Model of Yucca Mountain. Some of the unexpected findings include the occurrence of the zeol… more
Date: May 30, 1997
Creator: Chipera, S. J.; Vaniman, D. T.; Bish, D. L. & Carey, J. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Alteration history studies in the Exploratory Studies Facility, Yucca Mountain, Nevada, USA

Description: By mid-1995, the Exploratory Studies Facility (ESF) extended about 1. 1 km from Exile Hill westward toward Yucca Mountain, mostly within densely welded, devitrfied Tiva Canyon Tuff. Secondary mineral occurrences in this unit include breccia cements of mordenite, a fibrous zeolite, and vapor-phase deposits of silica, alkali feldspar, apatite, hollandite, amphibole, and zircon. Calcite is also a common secondary mineral in faults and fractures. Studies of water and gas contents in fluid inclusion… more
Date: April 1996
Creator: Levy, S. S.; Chipera, S. J. & Norman, D. I.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Petrography, mineralogy, and chemistry of calcite-silica deposits at Exile Hill, Nevada, compared with local spring deposits

Description: Chemical, mineralogic, and petrographic analyses of siliceous calcretes from Exile Hill east of Yucca Mountain, Nevada, indicate that pedogenic processes alone account for the formation of the calcretes. These calcretes have been interpreted by some observers as evidence of seismically triggered eruptions of deep water. Such an origin could have important consequences if Yucca Mountain is developed as an unsaturated site for the disposal of high-level nuclear waste. At odds with this hypothesis… more
Date: December 1995
Creator: Vaniman, D. T.; Chipera, S. J. & Bish, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mineralogic variation in drill core UE-25 UZ{number_sign}16, Yucca Mountain, Nevada

Description: Quantitative X-ray powder diffraction methods have been used to analyze 108 samples from drill core UE-25 UZ{number_sign}16 at Yucca Mountain, Nevada. This drill hole, located within the imbricate fault zone east of the potential Yucca Mountain repository site, confirms the authors` previous knowledge of gross-scale mineral distributions at Yucca Mountain and provides insight into possible shallow pathways for hydrologic recharge into the potential host rock. Analyses of samples from UE-25 UZ{n… more
Date: February 1, 1995
Creator: Chipera, S. J.; Vaniman, D. T.; Carlos, B. A. & Bish, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Comparison of neptunium sorption results using batch and column techniques

Description: We used crushed-rock columns to study the sorption retardation of neptunium by zeolitic, devitrified, and vitric tuffs typical of those at the site of the potential high-level nuclear waste repository at Yucca Mountain, Nevada. We used two sodium bicarbonate waters (groundwater from Well J-13 at the site and water prepared to simulate groundwater from Well UE-25p No. 1) under oxidizing conditions. It was found that values of the sorption distribution coefficient, Kd, obtained from these column … more
Date: August 1, 1996
Creator: Triay, I. R.; Furlano, A. C.; Weaver, S. C.; Chipera, S. J. & Bish, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Quantitative x-ray diffraction analyses of samples used for sorption studies by the Isotope and Nuclear Chemistry Division, Los Alamos National Laboratory

Description: Yucca Mountain, Nevada, is currently being investigated to determine its suitability to host our nation`s first geologic high-level nuclear waste repository. As part of an effort to determine how radionuclides will interact with rocks at Yucca Mountain, the Isotope and Nuclear Chemistry (INC) Division of Los Alamos National Laboratory has conducted numerous batch sorption experiments using core samples from Yucca Mountain. In order to understand better the interaction between the rocks and radi… more
Date: September 1, 1989
Creator: Chipera, S. J. & Bish, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Mineralogy and clinoptilolite K/Ar results from Yucca Mountain, Nevada, USA: A potential high-level radioactive waste repository site

Description: The Yucca Mountain Site Characterization Project is investigating Yucca Mountain, Nevada, as a potential site for a high-level nuclear waste repository. An important aspect of this evaluation is to understand the geologic history of the site including the diagenetic processes that are largely responsible for the present-day chemical and physical properties of the altered tuffs. This study evaluates the use of K/Ar geochronology in determining the alteration history of the zeolitized portions of… more
Date: November 1, 1993
Creator: WoldeGabriel, G.; Broxton, D. E.; Bish, D. L. & Chipera, S. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Manganese-oxide minerals in fractures of the Crater Flat Tuff in drill core USW G-4, Yucca Mountain, Nevada

Description: The Crater Flat Tuff is almost entirely below the water table in drill hole USW G-4 at Yucca Mountain, Nevada. Manganese-oxide minerals from the Crater Flat Tuff in USW G-4 were studied using optical, scanning electron microscopic, electron microprobe, and x-ray powder diffraction methods to determine their distribution, mineralogy, and chemistry. Manganese-oxide minerals coat fractures in all three members of the Crater Flat Tuff (Prow Pass, Bullfrog, and Tram), but they are most abundant in f… more
Date: July 1, 1990
Creator: Carlos, B. Arney; Bish, D. L. & Chipera, S. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Geologic evaluation of six nonwelded tuff sites in the vicinity of Yucca Mountain, Nevada for a surface-based test facility for the Yucca Mountain Project

Description: Outcrops of nonwelded tuff at six locations in the vicinity of Yucca Mountain, Nevada, were examined to determine their suitability for hosting a surface-based test facility for the Yucca Mountain Project. Investigators will use this facility to test equipment and procedures for the Exploratory Studies Facility and to conduct site characterization field experiments. The outcrops investigated contain rocks that include or are similar to the tuffaceous beds of Calico Hills, an important geologic … more
Date: October 1, 1993
Creator: Broxton, D. E.; Chipera, S. J.; Byers Jr., F. M. & Rautman, C. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The occurrence and distribution of erionite at Yucca Mountain, Nevada

Description: We have conducted an investigation to determine the occurrence and distribution of erionite, a potential carcinogen, at Yucca Mountain, Nevada. Using x-ray powder diffraction techniques yielding detection limits to below 0.05 wt %, we positively identified erionite in only 3 out of 76 bulk and 12 fracture samples investigated. The three erionite-bearing samples (J12-620/630, UE-25aNo.1-1296.2, and USW G4-1314) all occur above the static water level in clay/zeolite-rich horizons near the top of … more
Date: September 1, 1989
Creator: Chipera, S. J. & Bish, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Equilibrium modeling of the formation of zeolites in fractures at Yucca Mountain, Nevada

Description: Yucca Mountain, in southern Nevada, is currently being investigated to determine its suitability to host the first US high-level nuclear waste repository. One of the reasons that Yucca Mountain was chosen for study is the presence of thick sequences of zeolite-rich horizons. In as much as fractures may serve as potential pathways for aqueous transport, the minerals that line fractures are of particular interest. Zeolites are common in fractures at Yucca Mountain and consist mainly of clinoptilo… more
Date: August 1993
Creator: Chipera, S. J.; Bish, D. L. & Carlos, B. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Preliminary assessment of clinoptilolite K/Ar results from Yucca Mountain, Nevada: A potential high-level radioactive waste repository site

Description: At Yucca Mountain, evidence for at least three distinct temporal groups of clinoptilolites can be delineated from the preliminary K/Ar dates (2--3 Ma; 4--5 Ma; 7--11 Ma). The older K/Ar dates that are similar to published illite/smectite ages (9--12 Ma) may be crystallization ages, whereas the younger dates probably represent continued diagenetic reactions of older clinoptilolites with percolating fluids. The K/Ar dates increase with depth, suggesting minimal argon loss in the deeper samples. I… more
Date: March 1, 1992
Creator: WoldeGabriel, G.; Bish, D. L.; Broxton, D. E. & Chipera, S. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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