Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

South dakota


Published on

  • Be the first to comment

  • Be the first to like this

South dakota

  1. 1. Edgemont South Dakota Long-Term Stewardship Site Highlights Edgemont Site (page 3) Major Activities- disposal cell monitoring; access restrictions; inspections; maintenance Site Size -145 hectares (360 acres) Start/End Years - 1996/in perpetuity Estimated Average Annual Cost FY 2000-2006- $7,800
  2. 2. Table of Contents Table of Contents Edgemont Site .......................................................................... 3 South Dakota I
  3. 3. National Defense Authorization Act (NDAA) Long-Term Stewardship Repm·t South Dakota 2
  4. 4. Edgemont Site EDGEMONT SITE 1.0 SITE SUMMARY 1.1 Site Description and Mission The Edgemont Site (also known as Edgemont Vicinity Properties) is the location of a disposal cell built by the Tennessee Valley Authority (TVA) to encapsulate uranium mill tailings and other contaminated materials from the former Edgemont Mill, located 3.2 kilometers (two miles) away. The 145-hectare (360-acre) site is located in the southwest corner of the State of South Dakota, approximately five kilometers (three miles) south ofthe town of Edgemont. The site's disposal cell occupies 40 hectares (100 acres) of the site. Uranium ore processing operations at the nearby former mill created uranium mill tailings and other process- related wastes. TVA built the disposal cell at the Edgemont Site as part of the Edgemont Mill's remediation strategy. TVA encapsulated the tailings LONG-TERM STEWARDSHIP HIGHLIGHTS Major Long-Term Stewardship Activities - disposal cell monitoring; access restrictions; inspections; maintenance Total Site Area -145 hectares (360 acres) Estimated Volume ofResidual Contaminants- engineered unit 2.3 million cubic meters (3.0 million cubic yards) Long-Term Stewardship Start-End Years- 1996-in perpetuity Average Annual Long-Term Stewardship Cost FY 2000-2006-$7,800 Landlord- U.S. Department of Energy, Grand Junction Office and other contaminated wastes from the former Edgemont Mill materials in the cell in 1989. The current mission for the site is the long-term monitoring and maintenance of the disposal cell. The disposal site is subject to Title II of the Uranium Mill Tailings Radiation Control Act of1978 (UMTRCA). As such, the DOE Grand Junction Office is responsible for long-term stewardship activities at the site. DOE began long-term stewardship activities in 1996. The Edgemont Site had no historic mission, otherthan to be the final repository for the contaminated mill tailings and soils remediated from the former Edgemont Mill. The historic mission ofthe Edgemont Mill was to process and provide uranium to support the U.S. Government national defense program. Mines Development, Inc. built the Edgemont Mill in 1956 to process uranium ore and operated it until1974. Almost all the ore processed at the Edgemont Mill was mined in the Black Hills area of southwestern South Dakota and northeastern Wyoming. TVA acquired the mill facility in 1974, but decided against processing uranium ore at the mill based on engineering, economic, and environmental studies. Therefore, TVA never operated the mill. 1.2 Site Cleanup and Accomplishments In 1986, the U.S. Nuclear Regulatory Commission (NRC) approved the reclamation alternative to relocate the tailings to an engineered disposal site located 3.2 kilometers (two miles) from the former Edgemont Mill. Decommissioning activities began at the mill site in 1986, and reclamation was completed by 1989. Remediation of the Edgemont Mill consisted of demolishing site structures, excavating onsite contamination, and relocating mill tailings and contaminated structural materials into the Edgemont Site disposal cell. Concurrently, contaminated materials from vicinity properties in and around the town ofEdgemont were removed and disposed ofin the Edgemont Site's disposal cell. The disposal cell contains 4,000,000 tons ofcontaminated material, with an estimated total activity of 527 curies of radium-226. The base of the disposal cell lies on shale of the Belle Fourche Formation, which has a thickness of 56.4 meters (185 feet) immediately offthe site. Underlying the Belle Fourche Formation are more than 91 meters (300 feet) South Dakota 3
  5. 5. National Defense Authorization Act (NDAA) Long-Term Stewardship Report of generally impermeable strata that isolate the uppermost confined aquifer from the surface. Consequently, no groundwater remediation or monitoring is needed at this site. Edgemont Site TVA conducted all remediation at the site under its NRC license. Once reclamation was complete, the site was eligible for transfer to DOE for custody and long-term care. To enable the site's transfer to DOE, TVA provided a one-time payment to the U.S. Treasury to cover monitoring and maintenance costs. The Edgemont Site was transferred to DOE in June 1996 for long-term stewardship activities. 2.0 SITE-WIDE LONG-TERM STEWARDSHIP 2.1 Long-Term Stewardship Activities The DOE Grand Junction Office is responsible for performing long-term stewardship activities ofthe Edgemont Site. Access to the site is controlled by a locked stock fence around the perimeter of the site. DOE permits limited grazing on the land to maintain the health of the vegetation. Signs and markers notify potential intruders of the final site conditions. A metal sign displaying the international trefoil symbol for radioactive materials is placed at the site entrance and replaced as necessary. DOE performs sign and fence repairs on an as-needed basis. No drilling or other intrusive activities are allowed within the property boundary. Site records are in permanent storage at the DOE Grand Junction Office in Colorado. The types of records maintained include site characterization data, remedial action design information, the site completion report, long-term monitoring plans, annual inspection reports, and current and historic monitoring data. DOE develops South Dakota 4
  6. 6. Edgemont Site and updates records and reports required in the site long-term surveillance plan. These reports are submitted annually to the NRC to summarize, describe, and evaluate all surveillance and maintenance actions, as required under Title 10 of the Code ofFederal Regulations, Part 40. 2.2 Specific Long-Term Stewardship Activities Engineered Units The Edgemont Site disposal cell is approximately 426 meters (466 yards) wide and 944 meters (1,033 yards) long and occupies 40 hectares (100 acres) of the 145- hectare (360-acre) site. The cell contains approximately 2.3 million cubic meters (3.0 million cubic yards) of uranium mill tailings, soils, and construction debris contaminated with radium and thorium. STAKEHOWER INTERACTION Community interaction has been minimal since the remedial action was completed. Copies of the annual inspection report for the Edgemont Disposal Site are distributed to the State of South Dakota and to any stakeholders requesting them. The report is also published on the DOE Grand Junction Office website at The 2.7-meter (three-yard) thick cover over the tailings consists ofa 0.91-meter (one-yard) thick compacted clay radon barrier, a 1.52-meter (1.7-yard) thick compacted fill frost protection layer, and a 0.3-meter (0.3-yard) thick layer of topsoil material. The Edgemont Site disposal cell was designed and constructed to last for 200 to 1,000 years, in accordance with EPA standards. The cell design promotes rapid runoff of precipitation to minimize leachate. The site location and design were selected to minimize the potential for erosion from onsite runoff or storm water flow. All surrounding disturbed areas were regraded and reseeded to prevent wind and water erosion. An existing gully northwest of the cell and the containment dam face were armored with riprap for erosion protection. Additional riprap and grass-protected diversion ditches were installedto channel runoffwater away from the disposal cell. Long-term stewardship activities at the site include annual inspections of the disposal cell and maintenance, as needed. Grazing is allowed to enhance the success of the revegetation efforts. Groundwater Because of the more than 91 meters (300 feet) of generally impermeable strata that isolate the uppermost confined aquifer from the surface, no groundwater monitoring or remediation is needed. 2.3 Regulatory Regime In 1996, the Edgemont Site came under a general license issued by NRC for custody and long-term care of residual radioactive disposal sites (contained at Title 10 ofthe Code ofFederal Regulations, Section 40.28). The purpose ofthe general license is to ensure that such sites will be cared for in a manner that protects human health and safety and the environment. The general license went into effect when NRC agreed that the site conformed to cleanup standards and formally accepted the site-specific long-term surveillance plan. Long-term stewardship activities at the Edgemont Site are governed by several requirements in the following acts: the Uranium Mill Tailings Radiation Control Act of1978; the Atomic Energy Actof1954, as amended, and the National Environmental Policy Act of1969, as amended. 2.4 Assumptions and Uncertainties Because DOE Grand Junction Office has been performing long-term stewardship activities at the site since 1996, South Dakota 5
  7. 7. National Defense Authm·ization Act (NDAA) Long-Term Stewardship Repm·t long-term stewardship activities are well known and are not expected to dramatically change. The cap over the disposal site is not expected to be replaced for a minimum of 200 years. In addition, groundwater monitoring is not anticipated since there exists immediately offthe site an impermeable strata which isolates the uppermost confined aquifer from the surface. 3.0 ESTIMATED LONG-TERM STEWARDSHIP COSTS TVA made a one-time payment of $581,610 to the U.S. Treasury in June 1996, as required under UMTRCA, to cover the costs associated with long-term stewardship activities of the site. The cost estimates, identified below, are based on the costs of ongoing long-term stewardship activities at the site. Contingency costs, such as cap replacement, have not been incorporated in the cost estimates. Site Long-Term Stewardship Costs (Constant Year 2000 Dollars) Year(s) Amount Year(s) Amount Year(s) Amount FY 2000 $10,800 FY 2008 $7,000 FY 2036-2040 $34,100 FY 2001 $8,300 FY 2009 $7,000 FY 2041-2045 $34,100 FY 2002 $7,200 FY 2010 $6,900 FY 2046-2050 $34,100 FY 2003 $7,000 FY 2011-2015 $32,700 FY 2051-2055 $34,100 FY 2004 $7,100 FY 2016-2020 $31,800 FY 2056-2060 $34,100 FY 2005 $7,100 FY 2021-2025 $31,900 FY 2061-2065 $34,100 FY 2006 $7,000 FY 2026-2030 $33,700 FY 2066-2070 $34,100 FY 2007 $7,100 FY 2031-2035 $34,100 4.0 FUTURE USES The primary future use of the site will be the long-term surveillance and maintenance of the onsite disposal cell. DOE permits some limited grazing on the land to ensure the health of the vegetation. For more information about the Edgemont Site, please contact: Art Kleinrath, Long-Term Surveillance and Maintenance Program Manager U.S. Department of Energy, Grand Junction Office 2597 B3/4 Road, Grand Junction, CO 81503 Phone:970-248-6037 or visit the Internet website at South Dakota 6