Corrective Action Investigation Plan for Corrective Action 477: N-Tunnel Muckpile, Nevada Test Site - Revision: 1 - January 1999

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CORRECTIVE ACTION INVESTIGATION PLAN FOR CORRECTIVE ACTION UNIT 477: NEVADA TEST SITE

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CORRECTIVE ACTION INVESTIGATION PLAN FOR CORRECTIVE ACTION UNIT 477: N-TUNNEL MUCKPILE, NEVADA TEST SITE Defense Threat Reduction Agency Controlled Copy No. IQ 2621 Losee Road, Bldg. B-l, Suite 3050-01

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CORRECTIVE ACTION INVESTIGATION PLAN FOR CORRECTIVE ACTION UNIT 477: N-TUNNEL MUCKPILE, NEVADA TEST SITE Chief, Nevada Test Site Environmental Programs Defense Threat Reduction Agency

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Table of Contents List of Figures .......................................................................................................................... iii List of Tables............................................................................................................................ iv List of Acronyms and Abbreviations ...........................................................................................v 2.1 Physical Setting and Operational History.......................................................................8 3.1 Conceptual Site Model ................................................................................................. 13 3.2 Potential Contaminants of Concern ......................................................................15 3.4.2 Identification of the Decision.......................................................................... 19 3.4.3 Identification of Inputs to the Decision...........................................................19 3.4.4 Definition of Study Boundaries....................................................................... 20 3.4.5 Determination of Decision Rules .................................................................. 20 3.4.6 Specification on Decision Error Limits...........................................................20 3.4.7 Optimization of Design for Obtaining Data................................................... 21

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Table of Contents (Continued) Page ii of v 4.1.1 Muckpile Subsurface Characterization Borehole Drilling and Sampling . . 26 4.1.2 Buried Pond Borehole Drilling and Sampling .............................................. 30 4.1.3 Shallow Surface (0 to 5 ft) Borehole Drilling and Sampling ....................... 30 4.1.4 Background Native Soil Drilling and Sampling ........................................... 31 5.2 Potential Waste Streams .............................................................................................. 33

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Page iii of v List of Figures Number Title Page 1-1 N-Tunnel Muckpile Location Map, Nevada Test Site ......................................... 2 1-2 N-Tunnel Muckpile Site Map and Facilities Map, Nevada TestSite................... 3 1-3 Project Management Organizational Flow Chart ................................................ 6 2-1 Depositional Chronology of N-Tunnel Muckpile, Nevada TestSite..............10 2-2 N-Tunnel Muckpile Cross Sections, Nevada Test Site....................................... 11 3- 1 Conceptual Site Model For The N-Tunnel Muckpile, Nevada Test Site .... 16 4- 1 N-Tunnel Muckpile Boring and Surface Sample Location Map,

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List of Tables Number Title Page 3-1 Site Characterization Laboratory Analytical Requirements.................................18 4-1 N-Tunnel Corrective Action Investigation Borehole and 4-2 Muckpile Characterization Boreholes Random Locations and Page iv of v

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List of Acronyms and Abbreviations Corrective Action Decision Document Corrective Action Investigation Plan Code of Federal Regulations U.S. Department of Transportation Disintegrations per minute Defense Threat Reduction Agency (formerly Defense Nuclear Agency [DNA]) U.S. Environmental Protection Agency Federal Facility Agreement and Consent Order Number of samples Nevada Administrative Code Nevada Division of Environmental Protection Nevada Test Site Nevada Test Site Waste Acceptance Criteria Potential contaminant(s) of concern Personal protective equipment Parts per million Quality assurance and quality control Quality Assurance Project Plan Resource Conservation and Recovery Act

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This Corrective Action Investigation Plan (CAIP) has been prepared by the Defense Threat Reduction Agency (DTRA). The recommendations and corrective actions described within this plan apply to the investigation and future closure of the N-Tunnel muckpile in Area 12 of the Nevada Test Site (NTS) for which DTRA is responsible. This CAIP is consistent with the requirements of the Federal Facility Agreement and Consent Order (FFACO, 1996), agreed to by the U.S. Department of Defense, DTRA; the U.S. Department of Energy, Nevada Operations Office (DOE/NV); and the Nevada Division of Environmental Protection (NDEP). Chief, Nevada Test Site Environmental Programs, DTRA, is the NTS point of contact. This CAIP was based on an NDEP-approved, preexisting sampling and analysis plan generated by Science Applications International Corporation for the DTRA (formerly the Defense Nuclear Agency [DNA]) in 1992 (DNA, 1992). Much of the basis for this CAIP was incorporated directly from the earlier sampling and analysis plan, but some elements of the plan were modified to be consistent with FFACO requirements. Other modifications were made to incorporate recent technological developments and to facilitate field implementation. These modifications from the preexisting plan are described in Section 4.0 of this CAIP. Revision 0 of this CAIP was approved by the State of Nevada; however, since then the standardized CAIP outline has been changed effective December 1998. Therefore, the document has been revised to adhere to the current outline and is being issued as Revision 1. Additionally, changes have been made to the proposed sampling approach used for muckpile characterization. These changes were necessary to address logistical obstacles that may have been encountered during field implementation. The conceptual site model for the N-Tunnel Muckpile assumes that the potential contaminants of concern (PCOCs) would be associated with the disposed mining debris generated during the excavation phase of tunnel construction and from reentry (post-event) construction debris (approximately one percent of the total volume). Additionally, the PCOCs will most likely be located in isolated surface (0 to 5 feet [ft]) and subsurface (>5ft) "hot spots."

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The muckpile will be characterized using both statistical (i.e., random) and nonstatistical (i.e., biased) sampling strategies. The statistical investigation will satisfy the regulatory requirements which are outlined in Test Methods for Evaluating Solid Waste, SW-846 (EPA, 1986), and will consist of collecting samples from thirty borehole locations. The nonstatistical investigation will consist of biased sampling locations which were identified to target areas where contaminants may have been concentrated. Based on existing information, the most likely PCOCs contained in the muckpile are total petroleum hydrocarbons, volatile organic compounds, semivolatile organic compounds. Resource Conservation and Recovery Act metals, and radionuclides. Field screening methods will be used to detect volatile organics and radionuclides. Samples will be collected for laboratory analysis at each sample location. Additional sampling and analytical details are presented in Section 4.0. This CAIP will be submitted to the NDEP for approval. Field work will be conducted following approval of the plan. The results of the field investigation will support a defensible evaluation of corrective action alternatives in the Corrective Action Decision Document.

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This Corrective Action Investigation Plan (CAIP) has been developed in accordance with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the U.S. Department of Defense, Defense Threat Reduction Agency (DTRA); the U.S. Department of Energy, Nevada Operations Office (DOE/NV); and the Nevada Division of Environmental Protection (NDEP). The CAIP is a document that provides or references all of the specific information for planning investigation activities associated with Corrective Action Units (CAUs) or Corrective Action Sites (CASs) (FFACO, 1996). This CAIP contains the environmental sample collection objectives and the criteria for conducting site investigation activities at the N-Tunnel muckpile, identified under FFACO classification as CAU 477, CAS 12-06-03, located in Area 12 of the Nevada Test Site (NTS). Figure 1-1 indicates the location of the N-Tunnel muckpile and Figure 1-2 presents a site map of The purpose of the N-Tunnel corrective action investigation is to determine whether or not the N-Tunnel muckpile, the underlying native soils, or the underlying retention ponds have been impacted by potential contaminants of concern (PCOCs) at concentrations that exceed regulatory limits. The resulting data and information should will permit DTRA to make informed decisions about the possible future operation, use, or closure of the muckpile site. The N-Tunnel muckpile consists primarily of mining debris (rock) generated during tunnel excavation and construction in support of weapons effects testing. This debris may include cementitious mixtures and reentry material. Due to the unregulated disposal activities commonly associated with early muckpile operations, an investigation will be conducted to accomplish the following tasks: • Determine if identified PCOCs (chemical and radiological constituents) are present within or beneath the muckpile. • If present, determine the extent of the PCOCs within and beneath the muckpile.

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- Nevada Test Site Boundary The IT Group N-Tunnel Muckpile Location Map, Nevada Test Site

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LIMIT OF PILE BENCH LEVEL DRAINAGE AND DIRECTION PERMANENT BUILDING OR STRUCTURE N-Tunnel Muckpile Site Map and Facilities Map, Nevada Test Site The IT Group Reference: after DNA, 1992

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• Provide sufficient information and data to develop appropriate corrective action strategies for the muckpile which will be evaluated in the corrective action decision document This CAIP was developed using the U.S. Environmental Protection Agency (EPA) Data Quality environmental data will be used and to design a data collection program that will satisfy these goals. A summary of the results of the DQO process is in Section 3.0 of this plan. The scope of the N-Tunnel muckpile investigation includes the following: • Collecting background native soil samples, with a hand auger, field screening the samples for radioactivity, and analyzing at an off-site laboratory • Collecting samples of the surface and near-surface (0 to 5 feet [ft] below muckpile surface) muckpile materials and analyzing the samples using field-screening and off-site • Drilling subsurface muckpile characterization boreholes through the muckpile to 5 ft below the bottom of the muckpile • Conducting field screening of the subsurface (> 5 ft) borehole cores to test for volatile organic compounds (VOCs) and radioactivity to determine environmental sampling • Collecting random environmental samples from the subsurface cores for off-site • Drilling subsurface muckpile characterization boreholes through the muckpile and into the buried retention ponds located beneath the muckpile • Conducting field screening of the retention pond borehole cores to test for VOCs and radioactivity to determine environmental sampling intervals • Collecting environmental samples from the bottom of the retention pond for off-site Logging the subsurface boreholes cores to assess soil and waste physical characteristics

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The drilling and sampling locations will be selected based both on a statistical approach as specified in SW-846 (EPA, 1986) and a nonstatistical (i.e., biased) approach based on historical knowledge of the N-Tunnel muckpile operations. 1.3 Corrective Action Investigation Plan Contents Section 1.0 of this CAIP provides an introduction to the project, including the purpose and scope for the corrective action investigation. The FFACO requires that CAIPs address the following Health and safety The managerial organization for the N-Tunnel muckpile sampling event is illustrated by the flow chart in Figure 1-3. The technical aspects of this CAIP are contained in the N-Tunnel Muckpile Sampling and Analysis Plan (DNA, 1992) and in Sections 2.0 and 3.0 of this document. General field and laboratory quality assurance and quality control (QA/QC) issues are presented in selected sections of the Industrial Sites Quality Assurance Project Plan (QAPP) (DOE/NV, 1996a), as well as in this document. The Industrial Sites QAPP guidance is applicable for this sampling event. The specific aspects of field QA/QC are contained in approved procedures.

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Health & Safety Officer Quality Assurance Officer Corrective Action Investigation Contractor Project Manager Nevada Test Site Defense Threat Reduction Agency Nevada Test Site Defense Threat Reduction Agency Project Management Organizational Flow Chart

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The health and safety protocol to be followed for this project is documented in applicable sections of the Environmental Restoration Project Health and Safety Plan (DOE/NV, 1998) and will also be supplemented with a site-specific health and safety plan written prior to commencement of field work. In addition, as required by the U.S. Department of Energy Integrated Safety Management System, these documents outline the requirements for protecting the health and safety of the workers and the public, and procedures for protection of the environment. Site personnel will take every reasonable step to reduce or eliminate the possibility of injury, illness, or accident, and to protect the environment during all project activities. The following will be taken into consideration when evaluating the hazards associated control procedures for the field activities: • Potential hazards to site personnel and the public including, but not limited to, radionuclides, chemicals (such as heavy metals, VOCs, and semivolatile organic compounds [SVOCs]), adverse and rapidly changing weather, remote location, motor vehicle and heavy equipment operation, drilling, and excavations • Proper training of all site personnel to recognize and mitigate the anticipated hazards • Work controls to reduce or eliminate the hazards including engineering controls, substitution of less hazardous materials, personal protective equipment, and site workers ability to stop work • Occupational exposure monitoring to prevent overexposure to hazards such as radionuclides, chemicals, and physical agents (heat, cold, and high wind) • Use of the “as low as reasonably achievable” principle when dealing with radiological • Emergency and contingency planning and communication to include medical care and evacuation, decontamination and spill control measures, and appropriate notification of No CAU-specific public involvement activities are planned at this time; however, an overview of the public involvement process is documented in the Public Involvement Plan in Appendix V of the FFACO (1996). Field sampling activities are discussed in Section 4.0 of this CAIP. Waste management issues are discussed in Section 5.0 of this CAIP. The project schedule and records availability information are discussed in Section 6.0 of this CAIP, and project references are provided in Section 7.0 of this CAIP. Metric conversions for the English units used throughout the CAIP text are listed in Appendix A.

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Corrective Action Unit 477 is comprised of only one CAS, the N-Tunnel muckpile, which was operated between 1964 and 1993 during the period of nuclear and nonnuclear weapons effects testing in N-Tunnel. The process knowledge and the information that are currently available to assess the muckpile were examined during the DQO process (Section 3.0). This information includes aerial photographs, a chronology of test events in N-Tunnel, the spatial distribution and history of muckpile material deposition, internal DTRA reports, and interviews with former NTS workers. Specific details concerning wastes entering or released to the muckpile are limited, but available information is presented in Section 2.1. General background information pertaining to the history of the N-Tunnel muckpile (including a site history, the nature of muckpile materials, and waste management planning procedures and operations) is provided in the N-Tunnel Muckpile Sampling and Analysis Plan (DNA, 1992) and the Waste Management Planning Documentfor DNA Activities at the Nevada Test Site (DNA, 1990). The operational history of the N-Tunnel muckpile was determined from interpretations of aerial photographs and is described in existing documents and reports (DNA, 1990; DNA, 1992); a summary is presented in the following subsections. 2.1 Physical Setting and Operational History N-Tunnel, constructed beneath Rainier Mesa, was mined into bedded, ash flow tuff from 850 to 1,400 ft below the mesa surface. The tunnel was designed to withstand and contain pressures and temperatures created by the test events (see Table 2-1 for event history). Reentry to the tunnel after some nuclear tests involved additional horizontal mining and subsequent generation of reentry debris consisting of rock waste and construction materials such as cementitious mixtures, wood, cabling, and scrap metal which could have contained low levels of radioactivity (<0.4 millirem per hour). Mining debris and some reentry debris were stockpiled outside the tunnel entrance area, covering former drainage basins and washes. The materials generated during test events were hauled to the edge of the existing muckpile, dumped off the edge, and leveled. In the few cases where reentry debris was radioactive, the debris was capped with approximately 10 ft of clean cover material.

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Date Event Date Event 1964 Begin Mining 9/13/82 Huron Landing 6/28/67 Midi Mist 5/26/83 Mini Jade 8/24/68 Hudson Seal 8/21/83 Tomme/Midnight Zephyr 2/11/70 Diana Mist 4/6/85 Misty Rain 5/2/72 Misty North 10/9/85 Diamond Beech 10/12/73 Husky Ace 10/9/85 Millyard 6/19/74 Ming Blade 3/18/87 Middle Note 10/28/74 Hybla Fair 12/10/88 Misty Echo 5/12/76 Mighty Epic 7/25/90 Mineral Quarry 9/12/78 Diablo Hawk 9/18/92 Hunter’s Trophy 10/31/80 Miners Iron 9/21/93 Chemical Kiloton a N-Tunnel Environmental Sampling Data Report. Prepared by IT Corporation. Las Vegas, NV. (DNA, 1994) Records indicate that reentry wastes may have been excavated and disposed of as a unit, however, segregation …