Streamlined Approach for Environmental Restoration Work Plan for Corrective Action Unit 198: Test Cell C Filter Tank Closure Nevada Test Site, Nevada Revision No.: 1 - July 1998

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Streamlined Approach for Work Plan for Corrective Action Unit 198: Test Cell C Filter Tank Closure Nevada Test Site, Nevada Controlled Copy No.: Approved for public release; further distribution is authorized U.S. Department of Energy Nevada Operations Office j

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This report has been reproduced from the best available copy. DOE and DOE contractors can obtain copies of this report from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831, (423) 576-8401. This report is publicly available from the National Technical Information Service, U. S. Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161, (703) 487-4650.

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STREAMLINED APPROACH FOR ENVIRONMENTAL RESTORATION WORK PLAN FOR CORRECTIVE ACTION UNIT 198: TEST CELL C FILTER TANK CLOSURE NEVADA TEST SITE, NEVADA Nevada Operations Office Under Contract No. DE-AC08-96NV11718 Controlled Copy No.:

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STREAMLINED APPROACH FOR ENVIRONMENTAL RESTORATION WORK PLAN FOR CORRECTIVE ACTION UNIT 198: TEST CELL C FILTER TANK CLOSURE NEVADA TEST SITE, NEVADA Industrial Sites Subproject Runore C. Wycoff, Project warrager Nevada Environmental Restoration Project

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TABLE OF CONTENTS 2.0 UNIT DESCRIPTION AND CLOSUREOBJECTIVES .............................. 4 2.2 Site Location and Description........................................................ 4 3.1 Constituents of Concern........................................................................................... 11 4.0 REPORTS AND RECORDS AVAILABILITY...................................................................13 5.2 Potential Waste Streams.................................................................. 14 APPENDIX A - PROJECT ORGANIZATION APPENDIX C - NEVADA DIVISION OF ENVIRONMENTAL PROTECTION DOCUMENT

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TABLE OF CONTENTS (continued) Figure 1 - CAU 198 Site Location Map........................................................................................2 Figure 2 - CAU 198 Site Vicinity Map........................................................................................5 Figure 4 - Schematic of the Filter Tanks....................... ..............................................................7 Table 1 - Summary of Ractiological Soil Sample Results............................................................ 8

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ACRONYMS AND ABBREVIATIONS Section: Acr. A Abb. As Low As Reasonably Achievable Corrective Action Site Corrective Action Unit U.S. Department of Energy, Nevada Operations Office U.S. Department of Transportation Data Quality Objective Desert Research Institute Federal Facility Agreement and Consent Order Health and Safety Plan Minimal Detectable Activity milliroentgen per hour Nevada Division of Environmental Protection National Environmental Policy Act

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Stetson: Acr. A Abb. ACRONYMS AND ABBREVIATIONS (continued) NTS Nevada Test Site RWAP Radioactive Waste Acceptance Program RWMS Radioactive Waste Management Site RWP Radiological Work Permit SAFER Streamlined Approach for Environmental Restoration

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Section: Exec. Summ This plan addresses characterization and closure of Corrective Action Unit (CAU) 198 identified in the Federal Facility Agreement and Consent Order. The site is located at the Nevada Test Site (NTS) Area 25 Test Cell C Complex. The CAU consists of one Corrective Action Site (CAS) 25-23-12 which includes two aboveground radioactive wastewater filter tanks. The tanks have an estimated capacity of 2,271 liters (600 gallons) each and were used to filter radioactive wastewater originating from the Test Cell C “Nuclear Furnace 1" testing. The tanks contain radioisotopes. Process knowledge indicates that the most likely isotopes of concern include “Strontium and 137Cesium. The site is currently roped off and posted with Closure for this site will be completed by the following: • Excavate into the north side of the soil berm to provide access to the filter tanks. • Remove, cap, and seal, associated aboveground tank piping. • Remove the filter tanks from the concrete pad. • Isolate the filter tanks in a SEALANT)* container on site. • Transport the tanks to an approved low-level waste repository at the NTS pending Radioactive Waste Acceptance Program (RWAP) approval. If approval has not been provided by the time of tank removal, the SEALANT)* will be transported to the Area 6 Decontamination Facility where it can be stored in a controlled area pending disposal. Soils, subsurface piping, and the tanks’ concrete support pad will not be closed or removed during this field activity. These materials will require a new designation as a CAS. It is proposed that removal be completed during the closure activities of CAU 135 which includes the six underground wastewater storage tanks (CAS 25-02-02) associated with the Nuclear Furnace Test filtration and disposal system.

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This plan addresses characterization and closure of Corrective Action Unit (CAU) 198 identified in the Federal Facility Agreement and Consent Order (FFACO). The CAU is currently in Appendix II of the FFACO. Approval by the Nevada Division of Environmental Protection (NDEP) to move the CAU to Appendix III is pending. The site is located at the Nevada Test Site (NTS) Area 25 Test Cell C Complex (Figure 1). The CAU consists of one Corrective Action Site (CAS) 25-23-12 which includes two aboveground radioactive wastewater filter tanks used during the Nuclear Furnace Testing at Test Cell C. This plan provides the methodology for removing the filter tanks for closure. The tanks contain radioisotopes. The most likely isotopes include ^Strontium and l37Cesium which are commonly associated with nuclear reactor testing. The site is currently roped off and posted with “Caution Radiation Area” signs. Based on a radiological Site Demarcation Survey taken February 15, 1996, and a prefield activity survey completed on March 31,1998 no additional survey or analytical data is needed to.complete site closure. In addition, there is sufficient process knowledge of the tanks’ historical use, therefore, closure of CAU 198 will be completed using Streamlined Approach for Environmental Restoration (SAFER) process. The SAFER process combines elements of the Data Quality Objectives (DQO) process and the observational approach to help plan and conduct corrective actions. DQOs are used to identify the problem and define the type and quality of data needed to complete the investigation phase of the process. The observational approach provides a framework for managing uncertainty and planning decision making. The purpose of die investigation in the SAFER process is to verify the adequacy of existing information to implement the corrective action. The SAFER concept recognizes that technical decisions may be made based on incomplete, but sufficient, information, and the experience of the decision maker. Any uncertainties are addressed by documented assumptions that are verified by sampling and analyses, data evaluation, and on-site observations as planned activities progress, and by contingency plans as necessary. The remediation and closure may proceed simultaneously with site characterization as sufficient data are gathered to confirm or disprove the assumptions made in selecting the closure method. If, at any time during the site closure, new information is developed that indicates that the closure method should be revised, the closure activities will be redirected to more appropriately protect human health and the environment. Closure for CAU 198 will be completed by the following: • Excavate into the north side of the soil berm to provide access to the filter tanks. • Remove, cap, and seal, associated aboveground tank piping.

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• Remove the filter tanks from the concrete pad. • Isolate the filter tanks in a SEALANT)® container on site. • Transport the tanks to an approved low-level waste (LLW) repository at the NTS pending radioactive Waste Acceptance Program (RWAP) approval. If approval has not been provided by the time of tank removal, the SEALAND® will be transported to the Area 6 Decontamination Facility where it can be stored in a controlled area pending disposal. Soils, subsurface piping, and the tanks' concrete support pad will not be closed or removed during this field activity. These materials will require a new designation as a CAS. It is proposed that removal be completed during the closure activities of CAU 13S which includes the six underground wastewater storage tanks (CAS 25-02-02) associated with the Nuclear Furnace Test filtration and disposal system. The aboveground filter tanks are assumed to be dry. This assumption is based on the tank and piping design in addition to field observations. If during pipe removal it becomes apparent that liquids are still present within the tanks an attempt will be made to drain the liquid into 208 liter (L) (55 gallon [G]) drums. If liquids are spilled during any of the associated activities the spill will be contained if safe to do so. If a spill occurs the Department of Energy (DOE) and NDEP will be notified.

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2.0 UNIT DESCRIPTION AND CLOSURE OBJECTIVES The CAU consists of CAS 25-23-12. The filter tanks are located on the east side of Test Cell C, approximately 15.2 meters (m) (50 feet [ft]) from the facility fence line (Figure 2). A 2.4-m (8ft) to 3.0-m (10-ft) high earthen berm surrounds the tanks and is used as engineering control to minimize radiation exposure. The tanks have an estimated capacity of 2,271(L) (600 G) each and were used to filter radioactive wastewater originating from the Test Cell C “Nuclear Furnace 1" testing. As-built engineering drawings indicate that the filter media within the tanks consist of coarse gravels at the base to fine filter media (presumably sand) at the top. Wastewater was pumped into the filter tanks from subsurface storage tanks. Wastewater entered the filter tanks from the top and discharged from the bottom through pipes leading to a tile disposal field south of the tanks (Figure 3). Figure 4 shows the filter tanks with the influent and effluent piping and the direction of wastewater flow through the system. Section: Unit Description Dote: July IS. 1998 The Test Cell C complex was one of several facilities dedicated to the development of nuclear rocket technology. Test Cell C was designed to test nuclear rocket reactors (here after referred to as nuclear furnaces). During testing of the nuclear furnace, liquid hydrogen was injected through the furnace system as a coolant. Hydrogen gas effluent was decontaminated through a multi-stage process before being burned at the Test Cell C flare stack. A by-product of the decontamination process produced water contaminated with mixed fission products. Prior to discharge to a tile drain system the water was filtered through the two 600 G filter tanks previously described. In the early 1970's the reactor development, engine testing, and rocket development activities were concluded. The filter tanks have remained inactive since that time. 2.2 SITE LOCATION AND DESCRIPTION The site is located at the NTS Area 25 Test Cell C Complex (Figure 1). The tanks are located on the east side of Test Cell C, approximately 15.2 meters (m) (50 feet [ft]) from the facility fence line (Figure 2). The site is currently roped off and posted with “Caution Radiation Area” signs. Site closure will be completed by removing the filter tanks for disposal into a low-level waste repository at the NTS. The tanks contain radioisotopes. Constituents of concern may include ^Strontium, “Strontium, l37Cesium, “'Cerium, mIodine, and other common radionuclides associated with nuclear reactor testing (Shinkle, 1972). However, the most likely isotopes include “Strontium and 137Cesium

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Date: July IS, 1998 FROM TEST CELL "C VAULT FOR METER _ AND EFFLUENT MONITOR ! STORAGE TANK CONCRETE PAD SEWER LINECHAIN LINK WIRE FENCERADIOACTIVE WASTE DISPOSAL FIELD APPROXIMATE SCALE

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A radiological Site Demarcation Survey taken February 15, 1996, identified a maximum radiation level of 30 milliroentgen per hour (mR/hr) at 30 centimeters (cm) (1 ft) from the top of the tanks. A pre-work radiation survey was competed on March 31, 1998, under Radiological Work Permit (RWP) No. 98066 to identify if radioactivity was removable and where elevated readings were located on the tanks. Soil samples were also taken from the soil berm on the north interior and exterior where the berm will be breached for access as well as the soil area surrounding the concrete tank support pad. The March 31,1998 survey results indicate that removable beta is present on the tanks and piping. The maximum removable value reported was 969.50 disintegrations per minute. The maximum contact reading on the top of the tanks was 40 mR/hr. The exposure rate at 1.0 m (3.3 ft) from the tanks was measured at 5 mR/hr. The pre-work radiation survey results are provided as Appendix A. Gross alpha/beta and gamma 20 minute count soil results indicate that elevated beta (137Cesium) levels exist in the soils surrounding the concrete tank pad. Results are summarized in Table 1. TABLE 1 - SUMMARY OF RADIOLOGICAL SOIL SAMPLE RESULTS Section: Unit Detcription SAMPLE SAMPLE ISOTOPE RESULT MDA ERROR CAU198-1 Perimeter of concrete pad Gross Alpha 2.98 0.52 19 supporting filter tanks Gross Beta 17.5 1.1 5.8 CAU 198-2 North side of soil berm Gross Alpha 2.43 0.52 22 (interior and exterior Gross Beta 2.9 1.1 25 MDA - Minimum Detectable Activity Reference documentation describing how the filtration tanks were used and the processes involved support using process knowledge to determine that the tanks only filtered radiologically contaminated wastewater (DRI, 1988, Fraser, 1986, and Schinkle, 1972). However, to provide

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Section: Unit Description Dote: July IS. 1998 additional supporting documentation, a gamma spectroscopy unit will be used on the tanks prior to removal to estimate the activity level and isotopes of concern. If the analysis is unsuccessful, the activity level will be estimated using the historical Nuclear Furnace Testing data and the results of recent radiological site surveys. CAU 198 consists only of the two wastewater filter tanks. Therefore, closure of CAU 198 will be accomplished by removal and disposal of the tanks. Soils, subsurface piping, and the tanks’ concrete support pad will not be closed or removed during this field activity. Verification soil or filter media samples will not be collected. The closure activities will be completed using guidance from the following documents/permits: • Comprehensive Environmental Response. Compensation, and Liability Act Preliminary Assessment of DOE’s Nevada Operations Office Nuclear Weapons Testing Areas. Volume 1, Desert Research Institute, 1988. • Nevada Environmental Restoration Project Industrial Sites. Quality Assurance Project Plan. Nevada Test Site. Revision 1, DOE, 1996. • Nevada Environmental Restoration Project. Project Management Plan. Revision 0, • Nevada Test Site Underground Contaminants. Reynolds Electrical & Engineering • Nuclear Furnace 1 Effluent Clean Up System Efficiency. Space Nuclear Systems Office, • Radiological Work Permit BN 98101 and associated Bioassav Plan. Bechtel Nevada, • Site Specific Health and Safety Plan for Corrective Action Unit 198. Bechtel Nevada,

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Section: Field Activities Dote: July IS, 1998 Before field activities begin the following activities will have been completed: • Tortoise habitat and endangered species investigation. • Preparation of National Environmental Policy Act documentation (NEPA). • Preparation of a Health & Safety Plan (HASP). • A Cultural Resource Survey is not required since all work will be completed in previously disturbed areas. Off road driving in areas surrounding the site is not allowed. This site is located within the range of the desert tortoise. Therefore, a desert tortoise survey will be conducted. During all site activities, the terms and conditions of the NTS Biological Opinion (US Fish and Wildlife Services, 1992) will be followed. A hazard assessment and HASP have been prepared for this project. Work activities within the controlled area will be completed following as low as reasonably achievable (ALARA) methodology. Required personal protective equipment will be dictated by the approved HASP and the RWP. All Site workers will be Radiologic Worker II certified. Only properly trained/certified personnel will operate equipment and tools necessary to remove die tanks. Field activities will include: • Excavating into the soil berm to provide personnel access to the filter tanks. • Remove, cap, and seal, associated aboveground tank piping. • Remove the filter tanks from the concrete pad and place into a SEALAND* container on • Transport the tanks to an approved LLW repository at the NTS pending RWAP approval. If …