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  1. 1. Salmon Site Mississippi Long-Term Stewardship Site Highlights Salmon Site (page 3) Major Activities- groundwater monitoring; enforcing restrictions for access to and use of the subsurface Site Size- 595 hectares (1 ,470 acres) Start/End Years- 2003/in perpetuity Estimated Average Annual Cost FY2000-2006- $60,000
  2. 2. Table of Contents Table of Contents Salmon Site ............................................................................ 3 Mississippi I
  3. 3. National Defense Authodzation Act (NOAA) Long-Tenn Stewardship Report Mississippi 2
  4. 4. Salmon Site SALMON SITE 1.0 SITE SUMMARY 1.1 Site Description and Mission The Salmon Site covers approximately 595 hectares (1,470 acres) and is located 34 kilometers (21 miles) southwest ofHattiesburg, Mississippi. The U.S. Atomic Energy Commission (AEC), later known as the Department of Energy (DOE), used the site for two nuclear test detonations, Salmon and Sterling, to evaluate the seismic response of salt deposits to nuclear explosives. AEC conducted the first test, Salmon, at a depth of 828 meters (2,717 feet) in the Tatum Salt Dome in October 1964. AEC detonated the second test, known as Sterling, in the Salmon cavity in December 1966. The Salmon Site was also the location for two non-nuclear gas detonations used for seismic decoupling studies in the Vela Uniform Program. The LONG-TERM STEWARDSHIP HIGHLIGHTS Major Long-Term Stewardship Activities - groundwater monitoring; enforcing restrictions for access to and use of the subsurface Total Site Area- 595 hectares (1,470 acres) Estimated Volume ofResidual Contaminants- unknown Long-Term Stewardship Start-End Years- 2003-in perpetuity Average Annual Long-Term Stewardship Cost FY 2000-2006- $60,000 Landlord- U.S. Department of Energy non-nuclear gas detonations, Diode Tube in February 1969 and Humid Water in April1970, consisted of two methane-oxygen explosions conducted in the Salmon/Sterling cavity. These two detonations did not result in additional contamination of the site. The Salmon Site is currently owned by DOE. DOE's mission at the site is to complete surface remediation and continue long-term stewardship activities of the residual subsurface contamination in the test cavity. DOE anticipates transferring the site surface to the State of Mississippi after final closure of the subsurface is completed in 2003. At that time, DOE anticipates that the surface area at the site will be established as a demonstration forest and wildlife refuge. 1.2 Site Cleanup and Accomplishments DOE has developed site remediation plans and completed site characterization, modeling, and risk assessments for both the surface and subsurface areas. In October 1999, DOE initiated final site closure negotiations with the State of Mississippi. In addition, DOE has signed a Memorandum of Understanding with Lamar County that provides approximately $2 million to extend a drinking water system to residences in the vicinity ofthe site. This water system is expected to eliminate potential receptors for groundwater contamination. DOE expects to complete all remediation activities at the site by 2003. AEC's underground detonations at the site resulted in contamination of subsurface areas and groundwater. The potential contaminants of concern for the subsurface are mixed fission products, including plutonium, uranium, and tritium. During cleanup activities conducted at the site in 1972, AEC injected radioactively contaminated soils and water into the test cavity. The injection wells were then sealed with concrete and bentonite when the site was decommissioned. DOE does not plan to remediate subsurface contamination because of the lack of feasible technologies for removing subsurface contamination. However, DOE will use characterization and modeling data to define the areas that will require institutional controls. Negotiations with the State of Mississippi on final site closure criteria were initiated in 1999, and DOE expects all subsurface closure work will be completed by 2003. Mississippi 3
  5. 5. National Defense Authorization Act (NOAA) Long-Term Stewardship Report Potential surface contamination at the site resulted from drilling operations after the first test was conducted. Contaminants ofconcern include tritium and diesel fuel in abandoned mud pits, shallow disposal areas, and bum pits. In 1972, AEC initiated cleanup of surface contamination by excavating soils, decommissioning facilities, and disposing of wastes. In 1977, DOE conducted an additional sampling program, with more than 170 exploratory borings, and extensive soil and groundwater sampling. The results of the study showed that tritium contamination was left in the shallow mud pits during the 1972 site cleanup. As a result of this contamination, a plume of tritium extends northwest from the surface-ground-zero mud pits. DOE provided the site remedial investigation report to the State of Mississippi for review and State approval was received in May 2000. The State will make a decision on DOE's closure plans based on its review ofthe documentation. Assuming that the State accepts the current DOE plan, the surface contamination will be left in place to naturally decay to levels that will allow the site to be transferred to the State for use as a demonstration forest and wildlife refuge (approximately 10 years). 0 10 Miles Salmon Site 2.0 SITE-WIDE LONG-TERM STEWARDSHIP 2.1 Long-Term Stewardship Activities DOE expects that the subsurface will be closed and that DOE activities at the site will consist solely oflong-term stewardship activities beginning in 2003. DOE will not maintain an active presence at this site but will be responsible for monitoring and maintaining institutional controls over subsurface contamination. Final long-term stewardship requirements for the subsurface will be negotiated with the State ofMississippi. Periodic monitoring will be conducted to ensure that there is no contaminant migration from the test cavity to the groundwater. DOE does not anticipate that any long-term stewardship activities associated with the remediated surface Mississippi 4
  6. 6. Salmon Site contamination will be necessary once the existing levels of contamination have either attenuated or decayed to agreed upon concentration levels, which is estimated to take approximately 10 years. DOE maintains the project-specific records at the Nevada Operations Office in Las Vegas. These records include corrective action investigation workplans and reports; corrective action decision documents; health assessments; risk assessments; information submitted by the public; National Environmental Policy Act documents; and the Public Involvement Plan. The DOE Public Reading Facility and the Nevada Division of Environmental Protection Administrative Record are provided with copies of these documents. Upon the completion of the project, all DOE project files will be transferred to controlled storage at the Nevada Operations Office. Records are retained according to DOE records retention procedures. 2.2 Specific Long-Term Stewardship Activities Groundwater A monument has been placed at the site to mark the location of the test cavity. DOE will maintain institutional controls over the subsurface in perpetuity to prevent access to the test cavity, groundwater, and associated subsurface contamination. Institutional controls will include restricting surface intrusions on the site. DOE will continue to conduct annual groundwater monitoring at the site for at least 100 years after closure of the subsurface in 2003. DOE estimates that repair or replacement of groundwater monitoring wells will be required every 25 years. At the end ofthe post-closure groundwater monitoring period in 2103, assuming State regulatory agency approval, the monitoring wells will be plugged and abandoned in place in accordance with State regulations. 2.3 Regulatory Regime In accordance with applicable regulatory drivers listed below, DOE is responsible for identifying the nature and extent of contamination, determining potential risk to the public and the environment, and performing the necessary corrective actions in compliance with guidelines and requirements under federal regulatory drivers, as well as the state-specific regulatory drivers associated with the site location. These responsibilities are delegated to the DOE Office of Environmental Management. Resource Conservation and Recovery Act CRCRA): RCRA was the first comprehensive Federal effort to deal with solid and hazardous waste. RCRA regulates the generation, transportation, treatment, storage, and disposal of hazardous waste. At the Salmon Site, RCRA is enforced to protect human health and the environment; conserve energy and natural resources; reduce the amount of generated waste; and ensure that wastes are managed in an environmentally sound manner. Comprehensive Environmental Response. Compensation. and Liability Act CCERCLA): CERCLA supplies a system for identifying and providing corrective action to sites where hazardous substances have been released into any part of the air, water, groundwater, or land. Provisions of CERCLA include a National Contingency Plan, which establishes procedures for corrective action for hazardous substance releases. Salmon is not regulated under CERCLA; however, the regulations are useful as developmental guidelines. In addition to federal regulations, DOE must comply with State regulatory requirements. In most cases, State ofMississippi requirements are based on federal guidelines; however, in specific cases they may be more detailed and stringent than federal regulations. Nuclear Regulatory Commission (NRC): NRC regulations establish "free release" criteria. The State of Mississippi is not regulated under the NRC; however, the regulations are used as developmental guidelines. Mississippi 5
  7. 7. National Defense Authorization Act (NDAA) Long-Tenn Stewardship Report 2.4 Assumptions and Uncertainties DOE assumes that the State of Mississippi will approve the proposed surface restoration plan. Current land use designations and subsurface intrusion restrictions will continue into the foreseeable future. DOE will reevaluate and modify the subsurface restrictions, as appropriate, as part of the assessment and/or corrective action activities. DOE does not plan to remove subsurface contamination in and around the test cavities. However, DOE will develop subsurface models to define the contaminant boundary and refine the existing subsurface intrusion restrictions, if necessary. Post-closure monitoring will be conducted, as agreed upon in the site closure reports for the subsurface, in order to detect changes in the subsurface conditions. The schedule for groundwater monitoring after closure of the subsurface will be defined in the subsurface closure report. DOE assumes that groundwater monitoring will continue annually after subsurface closure is finalized in 2003 and that monitoring will be performed for 100 years (2003-2103). 3.0 ESTIMATED LONG-TERM STEWARDSHIP COSTS The cost profile in the table below applies to the entire Salmon site. The major long-term stewardship costs are for monitoring activities, data analysis, and repair and replacement of monitoring wells. The spikes in cost are a result of costs associated with repairing or replacing monitoring wells, which are assumed to require maintenance every 25 years. The long-term stewardship costs for the Salmon Site remain roughly constant at $40,000 annually through FY 2010. The higher costs in FY 2000 are associated with the new Real Estate Operations Permit (RE-OP) requirements. The cost increase in 2008 is the result of a periodic review and analysis of the data to evaluate and possibly refine the monitoring strategy. This review and analysis will occur every five years throughout the post- closure monitoring period (2003-2103). DOE projects that the total post-2070 (2071-2103) costs will be approximately $6.8 million dollars. Site Long"Term Stewardship Costs (Constant Ye~l- ~OOODollan) Year(s) Amount Year(s) Amount Year(s) Amount FY 2000 $180,000 FY 2008 $113,000 FY 2036-2040 $272,000 FY 2001 $40,000 FY 2009 $40,000 FY 2041-2045 $272,000 FY 2002 $40,000 FY 2010 $40,000 FY 2046-2050 $273,000 FY 2003 $40,000 FY 2011-2015 $272,000 FY 2051-2055 $2,772,000 FY 2004 $40,000 FY 2016-2020 $272,000 FY 2056-2060 $272,000 FY 2005 $40,000 FY 2021-2025 $272,000 FY 2061-2065 $272,000 FY 2006 $40,000 FY 2026-2030 $2,772,000 FY 2066-2070 $272,000 FY 2007 $40,000 FY 2031-2035 $272,000 PostFY 2070 $6,800,000 4.0 FUTURE USES Public Law 104-201 (the National Defense Authorization Act ofFiscal Year 1997, Section 2851(b), September 1996) allows DOE to transfer the site to the State of Mississippi. It is anticipated that the Salmon Site will be Mississippi 6
  8. 8. Salmon Site used as a demonstration forest and wildlife refuge. If the State accepts the property, agreements will be enacted for the transfer. The agreements will be completed prior to the completion of the closure activities and will be predicated on the final agreed upon surface closure criteria and future land use determinations. The anticipated end state for the Salmon Site will allow for future surface use at the site with an NRC designation of "no radiological restrictions." DOE will continue to restrict access to the test cavities, subsurface soil, and groundwater through the use of deed restrictions in perpetuity. For additional information about the Salmon Site, please contact: Monica Sanchez U.S. Department of Energy, Nevada Operations Office Environmental Restoration Division 232 Energy Way North Las Vegas, NV 89030-4199 Phone: 702-295-0160 sanchezm@nv.doe.gov Mississippi 7