skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Impact of Quaternary Climate on Seepage at Yucca Mountain, Nevada

Abstract

Uranium-series ages, oxygen-isotopic compositions, and uranium contents were determined in outer growth layers of opal and calcite from 0.5- to 3-centimeter-thick mineral coatings hosted by lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a permanent repository for high-level radioactive waste. Micrometer-scale growth layering in the minerals was imaged using a cathodoluminescence detector on a scanning electron microscope. Determinations of the chemistry, ages, and delta oxygen-18 values of the growth layers were conducted by electron microprobe analysis and secondary ion mass spectrometry techniques at spatial resolutions of 1 to about 20 micrometers ({micro}m) and 25 to 40 micrometers, respectively. Growth rates for the last 300 thousand years (k.y.) calculated from about 300 new high-resolution uranium-series ages range from approximately 0.5 to 1.5 {micro}m/k.y. for 1- to 3-centimeter-thick coatings, whereas coatings less than about I-centimeter-thick have growth rates less than 0.5 {micro}m/k.y. At the depth of the proposed repository, correlations of uranium concentration and delta oxygen-18 values with regional climate records indicate that unsaturated zone percolation and seepage water chemistries have responded to changes in climate during the last several hundred thousand years.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Yucca Mountain Project, Las Vegas, Nevada
Sponsoring Org.:
USDOE
OSTI Identifier:
893805
Report Number(s):
NA
MOL.20060420.0044, DC# 47438; TRN: US0606127
DOE Contract Number:
NA
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; CALCITE; CATHODOLUMINESCENCE; CAVITIES; CHEMISTRY; CLIMATES; COATINGS; ELECTRON MICROPROBE ANALYSIS; ELECTRON MICROSCOPES; HIGH-LEVEL RADIOACTIVE WASTES; MASS SPECTROSCOPY; OPALS; OXYGEN 18; SPATIAL RESOLUTION; URANIUM; WATER; YUCCA MOUNTAIN

Citation Formats

J.F. Whelan, J.B. Paces, L.A. Neymark, A.K. Schmitt, and M. Grove. Impact of Quaternary Climate on Seepage at Yucca Mountain, Nevada. United States: N. p., 2006. Web. doi:10.2172/893805.
J.F. Whelan, J.B. Paces, L.A. Neymark, A.K. Schmitt, & M. Grove. Impact of Quaternary Climate on Seepage at Yucca Mountain, Nevada. United States. doi:10.2172/893805.
J.F. Whelan, J.B. Paces, L.A. Neymark, A.K. Schmitt, and M. Grove. Fri . "Impact of Quaternary Climate on Seepage at Yucca Mountain, Nevada". United States. doi:10.2172/893805. https://www.osti.gov/servlets/purl/893805.
@article{osti_893805,
title = {Impact of Quaternary Climate on Seepage at Yucca Mountain, Nevada},
author = {J.F. Whelan and J.B. Paces and L.A. Neymark and A.K. Schmitt and M. Grove},
abstractNote = {Uranium-series ages, oxygen-isotopic compositions, and uranium contents were determined in outer growth layers of opal and calcite from 0.5- to 3-centimeter-thick mineral coatings hosted by lithophysal cavities in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a permanent repository for high-level radioactive waste. Micrometer-scale growth layering in the minerals was imaged using a cathodoluminescence detector on a scanning electron microscope. Determinations of the chemistry, ages, and delta oxygen-18 values of the growth layers were conducted by electron microprobe analysis and secondary ion mass spectrometry techniques at spatial resolutions of 1 to about 20 micrometers ({micro}m) and 25 to 40 micrometers, respectively. Growth rates for the last 300 thousand years (k.y.) calculated from about 300 new high-resolution uranium-series ages range from approximately 0.5 to 1.5 {micro}m/k.y. for 1- to 3-centimeter-thick coatings, whereas coatings less than about I-centimeter-thick have growth rates less than 0.5 {micro}m/k.y. At the depth of the proposed repository, correlations of uranium concentration and delta oxygen-18 values with regional climate records indicate that unsaturated zone percolation and seepage water chemistries have responded to changes in climate during the last several hundred thousand years.},
doi = {10.2172/893805},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 17 00:00:00 EST 2006},
month = {Fri Mar 17 00:00:00 EST 2006}
}

Technical Report:

Save / Share:
  • The overall objective of this study is to examine whether the modeling approach employed to estimate seepage into waste emplacement drifts yields results that are consistent with the observed seepage in the ESF South Ramp. It is important to realize that the modeling study reported here is not an attempt to predict, reproduce, or analyze the South Ramp seepage data. Such an effort would require the development of a specific model and a specific characterization and analysis approach best suited for capturing the hydrogeologic conditions in the South Ramp as they prevailed before and during the period of the seepagemore » observations. Instead, the conceptual framework and analysis approach developed for the estimation of long-term seepage into waste emplacement drifts in the Topopah Spring unit is used with minimal adjustments to examine whether the results of the probabilistic approach employed in the TSPA-LA (which considers uncertainty and spatial variability in fracture permeability, capillary strength, and local percolation flux) would provide reasonable seepage estimates, even if applied to the conditions in the South Ramp. If so, confidence can be gained that the TSPA-LA approach captures the processes relevant for the prediction of natural seepage into large underground openings.« less
  • Following a 5-month period of above-average precipitation during the winter of 2004-2005, water was observed seeping into the South Ramp section of the Exploratory Studies Facility of the proposed repository for high-level radioactive waste at Yucca Mountain, Nevada. Samples of the seepage were collected and analyzed for major ions, trace metals, and delta deuterium and delta oxygen-18 values in an effort to characterize the water and assess the interaction of seepage with anthropogenic materials used in the construction of the proposed repository. As demonstrated by the changes in the chemistry of water dripping from a rock bolt, interaction of seepagemore » with construction materials can alter solution chemistry and oxidation state.« less
  • 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.more » 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.« less
  • The Pahrump fault system is an active fault system located in Pahrump and Stewart Valleys, Nevada and California, in the southern part of the Basin and Range Province. This system is 50 km long by 30 km wide and is comprised of three fault zones: the right-lateral East Nopah fault zone, the right-oblique Pahrump Valley fault zone, and the normal West Spring Mountains fault zone. All three zones have geomorphic evidence for late Quaternary activity. Analysis of active fault patterns and seismic reflection lines suggests that the Pahrump basin has had a two-stage genesis, an early history associated with amore » period of low angle detachment faulting probably active 10-15 Ma, and a more recent history related to the present dextral shear system, probably active post-4 Ma.« less
  • The Yucca Mountain area, in the south-central part of the Great Basin, is in the drainage basin of the Amargosa River. The mountain consists of several fault blocks of volcanic rocks that are typical of the Basin and Range province. Yucca Mountain is dissected by steep-sided valleys of consequent drainage systems that are tributary on the east side to Fortymile Wash and on the west side to an unnamed wash that drains Crater Flat. Most of the major washes near Yucca Mountain are not integrated with the Amargosa River, but have distributary channels on the piedmont above the river. Landformsmore » in the Yucca Mountain area include rock pediments, ballenas, alluvial pediments, alluvial fans, stream terraces, and playas. Early Holocene and older alluvial fan deposits have been smoothed by pedimentation. The semiconical shape of alluvial fans is apparent at the junction of tributaries with major washes and where washes cross fault and terrace scarps. Playas are present in the eastern and southern ends of the Amargosa Desert. 39 refs., 9 figs., 1 tab.« less