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Page : pages
File Size : 37,93 MB
Release : 2006
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Water level measurements were performed and water samples collected from the Central Nevada Test Area model validation wells in September 2006. Hydraulic head measurements were compared to previous observations; the MV wells showed slight recovery from the drilling and testing operation in 2005. No radioisotopes exceeded limits set in the Corrective Action Decision Document/Corrective Action Plan, and no significant trends were observed when compared to previous analyses.
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Page : 26 pages
File Size : 20,64 MB
Release : 2008
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This report presents the 2007 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) for the Central Nevada Test Area (CNTA) Corrective Action Unit (CAU) 443. Responsibility for the environmental site restoration of the CNTA was transferred from the DOE Office of Environmental Management (DOE-EM) to DOE-LM on October 1, 2006. Requirements for CAU 443 are specified in the Federal Facility Agreement and Consent Order (FFACO 2005) entered into by DOE, the U.S. Department of Defense, and the State of Nevada and includes groundwater monitoring in support of site closure. This is the first groundwater monitoring report prepared by DOE-LM for the CNTA The CNTA is located north of U.S. Highway 6, approximately 30 miles north of Warm Springs in Nye County, Nevada (Figure 1). Three emplacement boreholes, UC-1, UC-3, and UC-4, were drilled at the CNTA for underground nuclear weapons testing. The initial underground nuclear test, Project Faultless, was conducted in borehole UC-1 at a depth of 3,199 feet (ft) (975 meters) below ground surface on January 19, 1968. The yield of the Project Faultless test was estimated to be 0.2 to 1 megaton (DOE 2004). The test resulted in a down-dropped fault block visible at land surface (Figure 2). No further testing was conducted at the CNTA, and the site was decommissioned as a testing facility in 1973.
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Page : 56 pages
File Size : 33,2 MB
Release : 2004
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This report discusses the long-term monitoring strategy developed for the Central Nevada Test Area (CNTA), where the Faultless underground nuclear test was conducted. It includes a thorough literature review of monitoring well network design. A multi-staged approach for development of the long-term monitoring well network for CNTA is proposed, incorporating a number of issues, including uncertainty of the subsurface environment, cost, selection of well locations, etc. The first stage is to use hydrogeologic expertise combined with model simulations and probability based approaches to select the first set of monitoring wells. The second stage will be based on an optimum design methodology that uses a suitable statistical approach, combined with an optimization approach, to augment the initial set of wells and develop the final long-term monitoring network.
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Page : 28 pages
File Size : 26,37 MB
Release : 2009
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This report presents the 2008 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) for the Central Nevada Test Area (CNTA) Subsurface Corrective Action Unit (CAU) 443. Responsibility for the environmental site restoration of the CNTA was transferred from the DOE Office of Environmental Management (DOE-EM) to DOE-LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 443 are conducted in accordance with the Federal Facility Agreement and Consent Order (FFACO 2005) entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes proof-of-concept monitoring in support of site closure. This report summarizes investigation activities associated with CAU 443 that were conducted at the site during fiscal year 2008. This is the second groundwater monitoring report prepared by DOE-LM for the CNTA.
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Page : 32 pages
File Size : 24,16 MB
Release : 2010
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This report presents the 2009 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) for the Central Nevada Test Area (CNTA) Subsurface Corrective Action Unit (CAU) 443. Responsibility for the environmental site restoration of CNTA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 443 are conducted in accordance with the Federal Facility Agreement and Consent Order entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes proof-of-concept monitoring in support of site closure. This report summarizes investigation activities associated with CAU 443 that were conducted at the site from October 2008 through December 2009. It also represents the first year of the enhanced monitoring network and begins the new 5-year proof-of-concept monitoring period that is intended to validate the compliance boundary.
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Page : 36 pages
File Size : 33,14 MB
Release : 2011
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This report presents the 2010 groundwater monitoring results collected by the U.S. Department of Energy (DOE) Office of Legacy Management (LM) for the Central Nevada Test Area (CNTA) Subsurface Corrective Action Unit (CAU) 443. Responsibility for the environmental site restoration of CNTA was transferred from the DOE Office of Environmental Management to LM on October 1, 2006. The environmental restoration process and corrective action strategy for CAU 443 are conducted in accordance with the Federal Facility Agreement and Consent Order entered into by DOE, the U.S. Department of Defense, and the State of Nevada. The corrective action strategy for the site includes proof-of-concept monitoring in support of site closure. This report summarizes investigation activities associated with CAU 443 that were conducted at the site from December 2009 through December 2010. It also represents the second year of the enhanced monitoring network and the 5-year proof-of-concept monitoring period that is intended to validate the compliance boundary.
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Page : 32 pages
File Size : 35,10 MB
Release : 2009
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This report presents results of data collected during the annual post-closure site inspection conducted at the Central Nevada Test Area, surface Corrective Action Unit (CAU) 417 in June 2009. The annual post-closure site inspection included inspections of the UC-1, UC-3, and UC-4 sites in accordance with the Post-Closure Monitoring Plan provided in the CAU 417 Closure Report (NNSA/NV 2001). The annual inspection conducted at the UC-1 Central Mud Pit (CMP) indicated that the site and soil cover were in good condition. Three new fractures were identified in the soil cover and were filled with bentonite chips during the inspection. The vegetation on the soil cover was adequate but showed signs of the area's ongoing drought. No issues were identified with the CMP fence, gate, or subsidence monuments. No issues were identified with the warning signs and monuments at the other two UC-1 locations.
Author : Ahmed E. Hassan
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Page : 56 pages
File Size : 50,24 MB
Release : 2003
Category : Groundwater
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Page : 70 pages
File Size : 29,18 MB
Release : 2013
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The Central Nevada Test Area was the site of a 0.2- to 1-megaton underground nuclear test in 1968. The surface of the site has been closed, but the subsurface is still in the corrective action process. The corrective action alternative selected for the site was monitoring with institutional controls. Annual sampling and hydraulic head monitoring are conducted as part of the subsurface corrective action strategy. The site is currently in the fourth year of the 5-year proof-of-concept period that is intended to validate the compliance boundary. Analytical results from the 2012 monitoring are consistent with those of previous years. Tritium remains at levels below the laboratory minimum detectable concentration in all wells in the monitoring network. Samples collected from reentry well UC-1-P-2SR, which is not in the monitoring network but was sampled as part of supplemental activities conducted during the 2012 monitoring, indicate concentrations of tritium that are consistent with previous sampling results. This well was drilled into the chimney shortly after the detonation, and water levels continue to rise, demonstrating the very low permeability of the volcanic rocks. Water level data from new wells MV-4 and MV-5 and recompleted well HTH-1RC indicate that hydraulic heads are still recovering from installation and testing. Data from wells MV-4 and MV-5 also indicate that head levels have not yet recovered from the 2011 sampling event during which several thousand gallons of water were purged. It has been recommended that a low-flow sampling method be adopted for these wells to allow head levels to recover to steady-state conditions. Despite the lack of steady-state groundwater conditions, hydraulic head data collected from alluvial wells installed in 2009 continue to support the conceptual model that the southeast-bounding graben fault acts as a barrier to groundwater flow at the site.
Author : Ahmed E. Hassan
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Page : 56 pages
File Size : 16,70 MB
Release : 2003
Category : Groundwater
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