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Title: Analysis of Single-Hole and Cross-Hole Tracer Tests Conducted at the Nye County Earl Warning Drilling Program Well Complex, Nye County, Nevada

Abstract

As part of the effort to understand the flow and transport characteristics downgradient from the proposed high-level radioactive waste geologic repository at Yucca Mountain, Nevada, single- and cross-hole tracer tests were conducted from December 2004 through October 2005 in boreholes at the Nye County 22 well complex. The results were analyzed for transport properties using both numerical and analytical solutions of the governing advection dispersion equation. Preliminary results indicate effective flow porosity values ranging from 1.0 x 10{sup -2} for an individual flow path to 2.0 x 10{sup -1} for composite flow paths, longitudinal dispersivity ranging from 0.3 to 3 m, and a transverse horizontal dispersivity of 0.03 m. Individual flow paths identified from the cross-hole testing indicate some solute diffusion into the stagnant portion of the alluvial aquifer.

Authors:
; ;
Publication Date:
Research Org.:
Yucca Mountain Project, Las Vegas, Nevada
Sponsoring Org.:
USDOE
OSTI Identifier:
893816
Report Number(s):
NA
MOL.20060711.0121, DC# 47439; TRN: US0606129
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; ADVECTION; ANALYTICAL SOLUTION; BOREHOLES; DIFFUSION; DRILLING; HIGH-LEVEL RADIOACTIVE WASTES; POROSITY; SOLUTES; TESTING; TRANSPORT; YUCCA MOUNTAIN

Citation Formats

A. Umari, J.D. Earle, and M.F. Fahy. Analysis of Single-Hole and Cross-Hole Tracer Tests Conducted at the Nye County Earl Warning Drilling Program Well Complex, Nye County, Nevada. United States: N. p., 2006. Web. doi:10.2172/893816.
A. Umari, J.D. Earle, & M.F. Fahy. Analysis of Single-Hole and Cross-Hole Tracer Tests Conducted at the Nye County Earl Warning Drilling Program Well Complex, Nye County, Nevada. United States. doi:10.2172/893816.
A. Umari, J.D. Earle, and M.F. Fahy. Fri . "Analysis of Single-Hole and Cross-Hole Tracer Tests Conducted at the Nye County Earl Warning Drilling Program Well Complex, Nye County, Nevada". United States. doi:10.2172/893816. https://www.osti.gov/servlets/purl/893816.
@article{osti_893816,
title = {Analysis of Single-Hole and Cross-Hole Tracer Tests Conducted at the Nye County Earl Warning Drilling Program Well Complex, Nye County, Nevada},
author = {A. Umari and J.D. Earle and M.F. Fahy},
abstractNote = {As part of the effort to understand the flow and transport characteristics downgradient from the proposed high-level radioactive waste geologic repository at Yucca Mountain, Nevada, single- and cross-hole tracer tests were conducted from December 2004 through October 2005 in boreholes at the Nye County 22 well complex. The results were analyzed for transport properties using both numerical and analytical solutions of the governing advection dispersion equation. Preliminary results indicate effective flow porosity values ranging from 1.0 x 10{sup -2} for an individual flow path to 2.0 x 10{sup -1} for composite flow paths, longitudinal dispersivity ranging from 0.3 to 3 m, and a transverse horizontal dispersivity of 0.03 m. Individual flow paths identified from the cross-hole testing indicate some solute diffusion into the stagnant portion of the alluvial aquifer.},
doi = {10.2172/893816},
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:

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  • A multiple-well interference (pumping) test was conducted in Miocene tuffaceous rocks at the C-hole complex at Yucca Mountain, Nev., from May 22 to June 12, 1995, by the US Geological Survey, in cooperation with the US Department of Energy. This pumping test was conducted as part of investigations to determine the suitability of Yucca Mountain as a potential site for the storage of high-level nuclear waste in a mined geologic repository. During the test, borehole UE-25 c{number_sign}3 was pumped for 10 days at an average rate of 17.9 liters per second. Drawdown in 6 observation wells completed in Miocene tuffaceousmore » rocks 29.0--3,525.6 meters from the pumping well ranged from 0 to 0.42 meters 14,000 minutes after pumping started. The spatial distribution of this drawdown indicates that a northwest-trending zone of discontinuous faults might be affecting ground-water movement in the Miocene tuffaceous rocks near the C-holes. No drawdown was observed in a borehole completed in a regional Paleozoic carbonate aquifer 630.0 meters from the pumping well. Consequently, it could not be determined during the pumping test if the Miocene tuffaceous rocks are connected hydraulically to the regional aquifer. Analyses of drawdown and recovery indicate that the Miocene tuffaceous rocks in the vicinity of the C-holes have transmissivity values of 1,600--3,200 meters squared per day, horizontal hydraulic conductivity values of 6.5--13 meters per day, vertical hydraulic conductivity values of 0.2--1.7 meters per day, storativity values of 0.001--0.003, and specific yield values of 0.01--0.2.« less
  • Test well USW H-4, located on the eastern edge of Yucca Mountain, Nye County, Nevada, penetrates volcanic tuffs through which water moves primarily along fractures. Data, collected from hydrologic and tracer tests and an acoustic-televiewer log, were used to quantify intrawell-bore flow directions and rates, permeability distribution, fracture porosity, and orientations of the hydraulic-conductivity ellipsoid for the test well. Borehole temperature data collected during a pumping test were used to identify 33 locations at which water was entering the hole. These results correlated well with results from radioactive-tracer surveys and packer tests of isolated intervals. Iodine-131 was used as amore » tracer under nonpumping conditions to study flow within the borehole, and to identify fractures that produced or accepted water. Water within the borehole was moving down from above and up from below toward the interval between 2500 and 3070 feet. Inflow and outflow were detected in the two most permeable zones in the borehole; however, the nondetection of it in the other test intervals may have resulted from monitoring periods that were too short. In the uppermost permeable zone, water moved down from above 2365 feet and exited the borehole between 2365 to 2375 feet; freshwater entered the borehole between 2380 and 2385 feet and moved downward. The probable shape and orientation of the hydraulic-conductivity ellipsoid were calculated from fracture frequency and orientation data. The plane containing the two larger principal axes of the ellipsoid strikes approximately north 23{sup 0} east and is nearly vertical. These two axes are approximately the same magnitude and are five to seven times larger than the smallest axis. Fracture porosity is about 10{sup -4} to 10{sup -3}, as estimated from the cubic law for hydraulic conductivity of fractures. 13 refs., 7 figs., 4 tabs.« less
  • The ER-6-1 multiple-well aquifer test-tracer test (MWAT-TT) investigated groundwater flow and transport processes relevant to the transport of radionuclides from sources on the Nevada Test Site (NTS) through the lower carbonate aquifer (LCA) hydrostratigraphic unit (HSU). The LCA, which is present beneath much of the NTS, is the principal aquifer for much of southern Nevada. This aquifer consists mostly of limestone and dolomite, and is pervasively fractured. Groundwater flow in this aquifer is primarily in the fractures, and the hydraulic properties are primarily related to fracture frequency and fracture characteristics (e.g., mineral coatings, aperture, connectivity). The objective of the multiple-wellmore » aquifer test (MWAT) was to determine flow and hydraulic characteristics for the LCA in Yucca Flat. The data were used to derive representative flow model and parameter values for the LCA. The items of specific interest are: Hydraulic conductivity; Storage parameters; Dual-porosity behavior; and Fracture flow characteristics. The objective of the tracer transport experiment was to evaluate the transport properties and processes of the LCA and to derive representative transport parameter values for the LCA. The properties of specific interest are: Effective porosity; Matrix diffusion; Longitudinal dispersivity; Adsorption characteristics; and Colloid transport characteristics. These properties substantially control the rate of transport of contaminants in the groundwater system and concentration distributions. To best support modeling at the scale of the corrective action unit (CAU), these properties must be investigated at the field scale. The processes represented by these parameters are affected by in-situ factors that are either difficult to investigate at the laboratory scale or operate at a much larger scale than can be reproduced in the laboratory. Measurements at the field scale provide a better understanding of the effective average parameter values. The scale of this tracer test is still small compared to the scale of a CAU, but is of sufficient scale to be generally representative of the processes that affect in-situ transport. The scale of the tracer test undertaken is limited by the rate of transport in the formation and the resultant time frame required for completing such a test. The measurements at the field scale will provide information for relating laboratory measurements for transport processes to the larger scale. This report describes the analysis of the tracer test data and development of a conceptual model of transport in the LCA in Yucca Flat.« less