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Title: Hydrophysical Evaluation of Wells TW-B, TW-7, UE-6d, U-2gg PSE 3A, U-10L 1, and UE-6e in Yucca Flat

Abstract

This study evaluated six wells in Yucca Flat in support of the Underground Test Area (UGTA) Activity conducted by the U.S. Department of Energy (DOE) at the Nevada National Security Site (NNSS). Accessibility and groundwater sampling conditions were assessed and if conditions permitted, samples were collected for tritium analysis. Four of the wells, TW-B, UE-6d, UE-6e, and TW-7 were sampled in support of UGTA responses to recommendations made by the Yucca Flat/Climax Mine External Peer Review Committee (Navarro, 2016). In addition to its role in support of these responses, TW-7 was included because it is listed in the NNSS Integrated Groundwater Sampling Plan (DOE, 2014) as a required sampling location, although it had not been sampled since 1994. U-2gg PSE 3A and U-10L 1 were evaluated to determine whether deteriorating well conditions can be addressed so that these wells can be used as additional sampling points in Yucca Flat.

Authors:
 [1];  [1];  [2];  [2];  [2]
  1. Desert Research Inst. (DRI), Las Vegas, NV (United States)
  2. Desert Research Inst. (DRI), Reno, NV (United States)
Publication Date:
Research Org.:
Desert Research Inst. (DRI), Reno, NV (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1358393
Report Number(s):
45274
DOE/NV/0000939-40
DOE Contract Number:
NA0000939
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES

Citation Formats

Pohlmann, Karl, Healey, John, Lyles, Bred, Cooper, Clay, and Hershey, Ronald L. Hydrophysical Evaluation of Wells TW-B, TW-7, UE-6d, U-2gg PSE 3A, U-10L 1, and UE-6e in Yucca Flat. United States: N. p., 2017. Web. doi:10.2172/1358393.
Pohlmann, Karl, Healey, John, Lyles, Bred, Cooper, Clay, & Hershey, Ronald L. Hydrophysical Evaluation of Wells TW-B, TW-7, UE-6d, U-2gg PSE 3A, U-10L 1, and UE-6e in Yucca Flat. United States. doi:10.2172/1358393.
Pohlmann, Karl, Healey, John, Lyles, Bred, Cooper, Clay, and Hershey, Ronald L. 2017. "Hydrophysical Evaluation of Wells TW-B, TW-7, UE-6d, U-2gg PSE 3A, U-10L 1, and UE-6e in Yucca Flat". United States. doi:10.2172/1358393. https://www.osti.gov/servlets/purl/1358393.
@article{osti_1358393,
title = {Hydrophysical Evaluation of Wells TW-B, TW-7, UE-6d, U-2gg PSE 3A, U-10L 1, and UE-6e in Yucca Flat},
author = {Pohlmann, Karl and Healey, John and Lyles, Bred and Cooper, Clay and Hershey, Ronald L.},
abstractNote = {This study evaluated six wells in Yucca Flat in support of the Underground Test Area (UGTA) Activity conducted by the U.S. Department of Energy (DOE) at the Nevada National Security Site (NNSS). Accessibility and groundwater sampling conditions were assessed and if conditions permitted, samples were collected for tritium analysis. Four of the wells, TW-B, UE-6d, UE-6e, and TW-7 were sampled in support of UGTA responses to recommendations made by the Yucca Flat/Climax Mine External Peer Review Committee (Navarro, 2016). In addition to its role in support of these responses, TW-7 was included because it is listed in the NNSS Integrated Groundwater Sampling Plan (DOE, 2014) as a required sampling location, although it had not been sampled since 1994. U-2gg PSE 3A and U-10L 1 were evaluated to determine whether deteriorating well conditions can be addressed so that these wells can be used as additional sampling points in Yucca Flat.},
doi = {10.2172/1358393},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 5
}

Technical Report:

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  • Borehole flow logging contributes a greater understanding of subsurface conditions than measuring well discharge only at land surface. Combining the results of up to nine borehole flow logs to estimate hydraulic conductivity with depth includes data averaging over vertical intervals and averaging of calculated hydraulic conductivities among the various flow logs. Data filtering is also necessary to aid in differentiating between changes in borehole flow rate due to flow turbulence (and other causes) and those associated with groundwater inflow. Borehole flow logging during well pumping has provided the quantity of groundwater iniflow and hydraulic conductivity at depth for three wells.more » The results provided are believed to be an appropriate balance between predictive accuracy and preserving spatial resolution.« less
  • The underground nuclear testing program of the US Department of Energy (USDOE) takes place at the Nevada Test Site (NTS), about 65 mi north-west of Las Vegas, Nevada. Underground nuclear tests at Yucca Flat, one of the USDOE test areas at NTS, have affected hydrologic conditions, including groundwater levels. The purpose of this map report, prepared in cooperation with USDOE, is to present selected water-level data collected from wells and test holes through December 1991, and to show potentiometric contours representing 1991 water-table conditions in the Yucca Flat area. The more generic term, potentiometric contours, is used herein rather thanmore » ``water-table contours`` because the hydrologic units contributing water to wells and test holes may not accurately represent the water table. The water table is that surface in an unconfined water body at which the pressure is atmospheric. It is defined by the altitude at which non- perched ground water is first found in wells and test holes. Perched ground water is defined as unconfined ground water separated from an underlying body of ground water by an unsaturated zone. This map report updates information on water levels in some wells and test holes and the resulting water-table contours in rocks of Cenozoic and Paleozoic age shown by Doty and Thordarson for 1980 conditions.« less
  • This report describes the results of a comprehensive geochemical evaluation of the groundwater flow system in the Yucca Flat/Climax Mine Corrective Action Unit (CAU). The main objectives of this study are to identify probable pathways for groundwater flow within the study area and to develop constraints on groundwater transit times between selected data collection sites. This work provides an independent means of testing and verifying predictive flow models being developed for this CAU using finite element methods. The Yucca Flat/Climax Mine CAU constitutes the largest of six underground test areas on the Nevada Test Site (NTS) specified for remedial actionmore » in the ''Federal Facility Agreement and Consent Order''. A total of 747 underground nuclear detonations were conducted in this CAU. Approximately 23 percent of these detonations were conducted below or near the water table, resulting in groundwater contamination in the vicinity and possibly downgradient of these underground test locations. Therefore, a rigorous evaluation of the groundwater flow system in this CAU is necessary to assess potential long-term risks to the public water supply at downgradient locations.« less
  • Vertical acceleration recordings of 21 underground nuclear explosions recorded at stations at Yucca Mountain provide the data for development of three two-dimensional crystal velocity profiles for portions of the Nevada Test Site. Paths from Area 19, Area 20 (both Pahute Mesa), and Yucca Flat to Yucca Mountain have been modeled using asymptotic ray theory travel time and synthetic seismogram techniques. Significant travel time differences exist between the Yucca Flat and Pahute Mesa source areas; relative amplitude patterns at Yucca Mountain also shift with changing source azimuth. The three models, UNEPM1, UNEPM2, and UNEYF1, successfully predict the travel time and amplitudemore » data for all three paths. 24 refs., 34 figs., 8 tabs.« less
  • Exploratory drill holes were drilled in Area 1 of western Yucca Flat, Nevada Test Site, to determine the thicknesses of alluvium and tuff and the depth to Paleozoic rocks underlying this unexplored part of Yucca Flat and to obtain hydrologic information. The three exploratory drill holes, UE1a, UE1b, and UE1c, were drilled during the period January 26 through February 7, l964.