National Defense Authorization Act (NOAA) Long-Term Ste\\ardship Report
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Maxey Flats Disposal Site
MAXEY FLATS DISPOSAL SITE'
1.0 SITE SUMMARY
1.1 Site Description and Mission
The Maxey Flats Disposal Site accepted low-level radioactive waste for disposal from government and private entities from across the United States (research laboratories, electric utilities, government and private health-care facilities, manufacturing companies, and nuclear powerplants). The disposal site is located approximately 14 kilometers (9 miles) northwest of Morehead, Kentucky, and 104 kilometers ( 65 miles) northeast of Lexington, Kentucky. The Commonwealth of Kentucky owns the 364-hectare (900-acre) site. The site was opened under a lease arrangement between the Commonwealth of Kentucky and the Nuclear Engineering Company (now U.S. Ecology, Inc.) of Louisville, Kentucky, in January 1963.
SITE HIGHliGHTS
Total Site Area- 364 hectares (900 acres) Estimated Volume of Residual Contaminants- disposal cell142,000 cubic meters (186,000 cubic yards) Current Landlord - Commonwealth of Kentucky Expected Long-Term Stewardship Start Year- 2003 Expected Future Landlord - Commonwealth of Kentucky Reason Not Subject to NDAA Requirements -DOE is not expected to be responsible for long-term stewardship at the site
Low-level radioactive waste was buried in 51 trenches measuring up to 198 meters (650 feet) long, 21 meters (70 feet) wide, and 9 meters (30 feet) deep. By the time disposal operations ended in 1977, Maxey Flats had accepted a total of approximately 142,500 cubic meters (186,675 cubic yards) of low-level radioactive waste.
Currently, the site is undergoing remedial action, which is expected to be complete by 2003. At that time, the Commonwealth of Kentucky will assume all responsibility for long-term stewardship needs, such as monitoring, surveillance, and maintenance.
1.2 Site Cleanup and Accomplishments
The waste disposed at the site consisted of approximately 242 metric tons (533,000 pounds) of source material (consisting of uranium and thorium or ores), 2.5 megacuries of byproduct materials, and 0.43 metric tons (950 pounds) of special nuclear material (plutonium and enriched uranium). During the operation of the facility, workers capped each disposal trench with a layer of soil after it was filled, but the earth eventually collapsed into the ditches. Water collected in the trenches, leaching radionuclides into the surrounding environment.
1This report is developed in response to a Congressional request in the Fiscal Year (FY) 2000 National Defense Authorization Act (NDAA). As requested by the Act, this report addresses current and anticipated longterm stewardship activities at each site or portion of a site by the end of calendar year 2006 ("Conference Report on S.1059, National Defense Authorization Act for Fiscal Year 2000," Congressional Record, August 5, 1999).
Based on current planning, the U.S. Department of Energy is not expected to be responsible for the long-term stewardship activities at the Maxey Flats Disposal Site. However, since DOE sent waste to the disposal site and was identified as a potentially responsible party, a description of the site and possible long-term stewardship responsibilities are included. (See Section 2.1.2 of Volume 1).
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National Defense Authorization Act (NDAA) Long-Term Ste\\ ardship Report
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Maxey Flats Disposal Site
In 1986, the U.S. Environmental Protection Agency (EPA) notified 832 potentially responsible parties, including DOE, that the EPA had placed the Maxey Flats Disposal Site on the National Priorities List. Other potentially responsible parties include other federal agencies, federal contractors, medical facilities, physicians, clinics, industry, state agencies, transporters, broker/haulers, and the land owner. In accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Record of Decision, cleanup levels will be achieved through natural stabilization, with low-level waste remaining on site in the subsurface and in aboveground vaults.
The selected remedy includes extraction, solidification, and onsite disposal of approximately 3.8 million liters ( 1 million gallons) of radioactive trench leachate in the Earth Mounded Concrete Bunkers; construction of a temporary cap (intended to last 100 years) composed of a synthetic liner; and construction of a final cap once the waste is stabilized. The final cap will cover both the trenches and the Earth Mounded Concrete Bunkers. The stabilized waste will remain in the above-ground bunkers (i.e., Earth Mounded Concrete Bunkers). All site structures will be demolished and the site will be regraded.
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ACCOMPLISHMENTS
• Earth Mounded Concrete Bunkers have been constructed for onsite waste disposal
• The majority of trench leachate material has been extracted, solidified, and disposed
BY 2006 MAXEY FLATS DISPOSAL SITE WILL HAVE:
• Completed trench leachate extraction, solidification, and disposal
• Regraded the site and extended the synthetic liner
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Maxey Flats Disposal Site
Primary contaminants of concern in the ground and surface water include radionuclides, primarily tritium. Surface water control systems have been installed to limit infiltration and to control surface water runoff. Water monitoring equipment, as part of an Infiltration Monitoring System, will be installed in trenches and within wells, to detect potential accumulation of leachate in trenches.
As a potentially responsible party, DOE is responsible for approximately forty percent of the remediation costs. This responsibility will cease when the interim cap is in place and the initial closure construction support activities are complete. DOE assumes that these activities will be complete by 2003. DOE anticipates no further liability once it has made the final payment, currently scheduled for 2003.
2.0 POTENTIAL LONG-TERM STEWARDSHIP ACTIVITIES
The Commonwealth of Kentucky is responsible for long-term stewardship, including surveillance, maintenance, and monitoring of stabilized waste, as stated in the Consent Decree developed between the potentially responsible parties. Currently, the Maxey Flats Disposal Site is fenced to control access. As part of long-term stewardship, the Commonwealth of Kentucky will continue to maintain and repair the fence, as needed. The Commonwealth of Kentucky will also be responsible for maintaining and updating site records. Types of records 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.
The interim cap will cover approximately 26 hectares (65 acres) of the site. Upon completion of the interim cap, intensive monitoring will be conducted for two five-year periods to evaluate the need for additional remedial action. Erosion and runoff controls will be improved. A final cap will be placed over the site after disposal trenches have subsided and waste has had sufficient time to stabilize. In accordance with CERCLA, five-year reviews will be required, as well as cap maintenance and inspection.
Ground and surface water will be monitored in trenches and within wells to detect potential accumulation of leachate. Radionuclide testing of groundwater and surface water will be performed, as appropriate, on a routine basis.
3.0 EXPECTED FUTURE USES AND SITE RESPONSIBILITY
Maxey Flats will remain a permanent low-level waste disposal site under controlled access. The site is currently managed by the landlord, Commonwealth of Kentucky. DOE has no control or management responsibility. As of 2003, DOE anticipates no further liability because it will have fulfilled its responsibilities as a potentially responsible party.
For additional information about the Maxey Flats Disposal Site, please contact:
Fazi Sherkat, Manager Superfund Branch Kentucky Division of Waste Management 14 Reilly Road Frankfort, KY 40601 Phone: 502-564-6716
Paul Beam U.S. Department of Energy Office of Technical Program Integration EM-22, Room 2151 Germantown, MD 20874 Phone: 301-903-8133
or visit the Internet website at http://www.nr.state.ky.us/nrepc/dep/waste/dwmhome.htm
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Paducah Gaseous Diffusion Plant
PADUCAH GASEOUS DIFFUSION PLANT
1.0 SITE SUMMARY
1.1 Site Description and Mission
The Paducah Gaseous Diffusion Plant enriches uranium for use in commercial nuclear facilities (formerly for the U.S. Department of Energy (DOE) and its predecessor agencies). The plant is located on a 1 ,385-hectare (3,423-acre) reservation owned by DOE, approximately eight kilometers (five miles) west of the City of Paducah, Kentucky. The gaseous diffusion plant itself is located within an industrialized, securitycontrolled area that comprises 304 hectares (7 50 acres), roughly in the center of the reservation. The plant began operating in 1952, supplying enriched uranium through a gaseous diffusion process for both government and commercial nuclear fuel needs. In 1992, Congress passed the Energy Policy Act and, under its provisions, DOE leased the uranium enrichment operations at Paducah to the United States Enrichment Corporation (USEC). However, the Act required DOE to retain responsibility for remedial action of environmental releases and for decontamination
WNG-TERM STEWARDSHIP HIGHLIGHTS
Major Long-Term Stewardship Activities- engineered cap, groundwater, and surface water monitoring; maintenance; institutional control enforcement Total Site Area- 1,385 hectares (3,423 acres) *Estimated Volume of Residual Contaminants - soil1.2 million cubic meters (1.6 million cubic yards); groundwater 23,000 cubic meters (30,000 cubic yards); engineered units unknown; facilities unknown; surface water/sediments unknown Long-Term Stewardship Start-End Years- 2000-in perpetuity Average Annual Long-Term Stewardship Cost FY 2000-2006- $6,495,000 Landlord- U.S. Department of Energy, Office of Nuclear Energy (Uranium enrichment facilities leased to United States Enrichment Corporation) *The estimated volume indicates only the known amounts of residual contaminants. For certain portions discussed for this site, exact volume is not known at this point. For specific discussions, please see Section 2.2.
and decommissioning of facilities. Uranium enrichment operations and related waste disposal activities at Paducah resulted in both onsite and offsite contamination of the environment with radiological and chemical substances. Investigation of offsite contamination was initiated in 1988. DOE is currently conducting remediation activities and anticipates completion by 2010.
Presently, the site supports three missions: (1) continued enrichment of uranium by USEC for use in commercial nuclear facilities; (2) ongoing environmental restoration and related waste management activities by DOE's Office of Environmental Management; and (3) continued interim storage of depleted uranium hexaflouride until a conversion facility is constructed. Current long-term stewardship activities include monitoring surface water, groundwater, and capped landfills. Once remediation is complete, the long-term stewardship activities will also include monitoring and maintaining engineered controls and enforcing institutional controls.
1.2 Site Cleanup and Accomplishments
In May 1994, the U.S. Environmental Protection Agency (EPA) placed the Paducah site on its National Priorities List, thereby establishing it as a high priority for cleanup under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Currently, DOE is conducting cleanup activities under the conditions established in a Federal Facility Agreement signed by DOE, EPA, and the Commonwealth of Kentucky. The Federal Facility Agreement coordinates cleanup activities conducted at the site under both the Resource Conservation and Recovery Act of 1976 (RCRA) and CERCLA regulations.
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~ Groundwater Contamination
- Soil Contamination
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Paducah Gaseous Diffusion Plant
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Paducah Gaseous Diffusion Plant
The cleanup strategy at Paducah consists of a multi-phase process:
1) Mitigate immediate risks, both onsite and offsite; 2) Reduce further migration of offsite contamination; 3) Address onsite sources of offsite contamination; 4) Address the remaining areas of onsite contamination; and 5) Complete decontamination and decommissioning of the DOE facilities.
Site-wide, DOE has made significant progress in characterizing site problems and implementing interim actions to address immediate threats and reduce further migration of off site contamination (e.g., supplied alternate drinking water to affected residents, construction and operation of two offsite groundwater extraction and treatment systems). Now that those initial threats are under control, the focus of the cleanup program is shifting to the onsite source areas. As the first step, DOE completed an extensive investigation effort to identify and characterize the primary sources of groundwater contamination in 2000.
Another significant action currently underway includes removal of a pile of contaminated scrap metal (crushed drums), known as Drum Mountain, in 2000 and disposal of the packaged waste in early 2001. This area has been identified as a potential source of offsite contamination and geographically overlies several burial grounds that are of high priority. The primary field work at Drum Mountain was completed in September 2000. Removal of Drum Mountain will represent about 10 percent of the total contaminated scrap metal stored at the site. DOE and the regulatory agencies have established a baseline schedule for removing the remaining scrap metal by 2004.
During past operations, RCRA hazardous wastes, hazardous constituents, and hazardous substances were released into the environment in areas such as burial grounds, spill sites, landfarms, surface impoundments, and underground storage tanks. Releases from some source areas have migrated into the surrounding soils, underlying groundwater, and adjacent surface water and sediments.
The primary contaminants of concern in soils at Paducah include trichloroethylene (TCE), polychlorinated biphenyl (PCBs), and radionuclides. Since characterization of the soils has not been completed, the total volume of contaminated soils has yet to be determined. However, analyses to date indicate that approximately 80 hectares (200 acres) of soils are impacted by residual contamination. Cleanup of the surface soils focuses on addressing risks to onsite industrial workers and offsite receptors potentially exposed through contaminant migration. DOE will remediate areas within the security fence and the buffer zone to industrial cleanup levels and areas outside of the fence to recreational levels. Soil contamination is planned for excavation. In accordance with EPA's Toxic Substances Control Act cleanup level regulations, DOE's current assumption is to cleanup PCBs to 10-25 parts per million (for industrialized areas for human health risk) and remediate radionuclides to 15-25 millirem per year.
ACCOMPLISHMENTS
• Eliminated imminent threats by providing residents alternate drinking water
• Reduced further migration of offsite groundwater contamination through installation of pump and treat systems
• Completed remedial investigations for the major Dense Non-Aqueous Phase Liquid (DNAPL) sources of offsite contamination
BY 2006 PADUCAH WILL HAVE:
• Completed removal of 65,000 tons of scrap metal • Completed remedial construction for cleanup of
groundwater sources • Completed remediation activities of contamination
of the North-South Diversion Ditch
However, the Commonwealth of Kentucky has suggested PCB cleanup levels as low as one part per million for human health. This issue is unresolved, and the outcome could have a significant impact on the amount of residual contamination remaining in place. The primary goal is to conduct cleanup or stabilization activities that
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National Defense Authm·ization Act (NDAA) Long-Term Stewardship Report
will reduce contamination to levels allowing maximum reuse of the industrialized area with minimal institutional controls.
Due to past operations at Paducah, groundwater contamination from dense non-aqueous phase liquids (DNAPLs) consisting of TCE is a long-term source of concern. The groundwater plumes extend over 930 hectares (2,300 acres), both on and off the site, affecting approximately 23,000 cubic meters (30,000 cubic yards) of groundwater. The offsite contamination has spread into a residential use area, where DOE has provided an alternative, public water supply. DOE is currently mitigating the high-concentration portions of the offsite plumes through pump-and-treat operations and monitoring of the groundwater plumes, both onsite and offsite. DOE is conducting a feasibility study to identify and evaluate groundwater treatment alternatives, including treatment of groundwater contamination sources. The final remediation strategy for this contamination has not been selected; however, offsite groundwater will be remediated to residential cleanup levels. The target cleanup levels for the contaminants of concern, TCE and technetium-99 (Tc-99), are five parts per billion and four millirem per year, respectively. Onsite groundwater pumping, treating, and monitoring will continue. The response action for this contamination will likely include containment of source areas, mass removal of highconcentration areas, and natural attenuation of the lower concentration, dissolved-phase plume.
Surface water and sediments covering 26 hectares (65 acres) in the Big and Little Bayou watersheds (both on and off the site) are contaminated with PCBs, radionuclides, and metals. DOE's strategy is to protect both the ecosystem and recreational users of the Big and Little Bayou watersheds. DOE has not completed the remedial investigation of the surface water and sediment contamination. Consequently, neither a detailed description of the nature and extent of contamination nor any estimate of the expected remedial strategy and levels of residual contamination are available at this time. In addition, DOE and the Commonwealth of Kentucky have not agreed upon a cleanup standard for PCBs, which will significantly affect the amount of contamination remaining after cleanup activities are complete. The Commonwealth of Kentucky has suggested levels significantly below (in comparison to the levels proposed for surface soils posing human health risks) one part per million for PCBs in sediments posing ecological risks. In the meantime, surface waters are monitored, and postings (e.g., instructional signs stating what one can and cannot do), fences, and deed restrictions currently protect against improper use of surface water. There are also fish advisories posted in Little Bayou Creek, which runs through the Western Kentucky Wildlife Management Area.
Engineered units at Paducah include three closed industrial/solid waste landfills, one currently operational industrial/solid waste landfill, and one proposed onsite disposal cell. The three closed landfills are capped and monitored in accordance with the state RCRA regulations. The active landfill is assumed to continue operations until 2005, at which time it will be closed in accordance with state RCRA regulations. The proposed onsite disposal cell is a very preliminary remedial action strategy that has not been formally approved by DOE, regulators, or other affected parties. This onsite disposal cell would contain approximately 1.1 million cubic meters (1.5 million cubic yards) of decontamination and decommissioning and other material generated by Paducah cleanup projects. Formal closure of this onsite disposal cell would be managed under CERCLA.
Most of the uranium processing facilities at the Paducah site remain operational; only two have been transferred to DOE's Environmental Management program for cleanup. These two facilities, known as "C-41 0 and C-340," comprise 26,000 square meters (280,000 square feet) and have not undergone detailed characterization. However, the buildings and subsurface soils are likely to be radioactively contaminated due to uranium trioxide conversion and uranium hexafluoride reduction operations. The goal for cleaning up these facilities is to decontaminate and demolish them and maximize industrial reuse of the remaining land, with minimal institutional controls, by 2010.
There are four active diffusion cascade buildings (more than 186,000 square meters (2 million square feet)),
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Paducah Gaseous Diffusion Plant
portions of which are potentially contaminated with radionuclides, PCBs, VOCs, and metals. While it is unclear when USEC will cease uranium processing operations at Paducah, the cleanup and final disposition of those facilities may significantly affect the nature of residual contamination at the site. DOE assumes that buildings that are unsuitable for reuse or pose an unacceptable risk will be placed under long-term surveillance and maintenance pending final decontamination and decommissioning.
2.0 SITE· WIDE LONG· TERM STEWARDSHIP
2.1 Long-Term Stewardship Activities
The primary steward for the Paducah Gaseous Diffusion Plant site will be DOE. The long-term stewardship activities will include monitoring the surface and groundwater, maintaining engineered controls (e.g., landfill cap/covers, etc.), enforcing access restrictions, and maintaining institutional controls. Long-term stewardship activities are expected to continue in perpetuity; however the duration will be adjusted as requirements are better defined.
Institutional controls will include deed restrictions prohibiting the use of onsite groundwater and
LONG-TERM STEWARDSHIP GOALS
Apply deed restrictions to prohibit groundwater use and residential development Implement institutional controls to identify areas of buried waste and warn the public of its presence Provide long-term monitoring to ensure that engineered controls continue to contain hazardous and radiological contamination
residential development on DOE property. DOE will maintain a permit program that will control excavation, penetration, or other use of residually contaminated areas. Notices, deed restrictions, and other information (e.g., location and risk) associated with the presence of residual contaminants remaining onsite will be filed with appropriate city and county offices.
The Paducah industrial complex site is currently surrounded by a security fence, with access controlled by security guards. DOE will maintain access control to protect classified information. Entrance and perimeter signs clearly identify the Paducah site as a DOE-owned facility with access restrictions. Further, contaminated areas outside the fenced complex are posted as such and restricted, consistent with applicable requirements.
Currently, DOE is responsible for long-term record-keeping associated with environmental contamination at the site. DOE plans to maintain the existing administrative record for CERCLA actions and utilize it as a long-term repository for records in accordance with CERCLA, DOE Orders, and the Land Use Control Assurance Plans. Site records are kept in permanent storage at the Paducah site and real property records are retained at the DOE Oak Ridge Office. Types of records maintained include site characterization data, remedial action design information, monitoring plans, monitoring results, and action completion reports. Of particular importance are the Land Use Control Assurance Plan and the STAKEHOWER INVOLVEMENT corresponding Land Use Control Implementation Plans that will be developed for each cleanup area. The Land Use Control Implementation Plans will contain notification and reporting requirements. Information collection systems need to be reviewed to determine a way to flag information relevant for long-term stewardship and to store the information in retrievable form for the long term.
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DOE has established a site-specific advisory board and the Paducah Area Community Reuse Organization to facilitate community involvement in cleanup decisions and long-term reuse initiatives for the site. In addition, DOE has developed and is implementing a Community Relations Plan that incorporates the public participation requirements of RCRA and CERCLA.
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National Defense Authodzation Act (NDAA) Long-Term Ste\\ardship Report
2.2 Specific Long-Term Stewardship Activities
Soil
DOE will monitor conditions at all release sites to ensure regulatory compliance. CERCLA five-year reviews will be conducted following remediation in areas where contamination or waste is left in place. Approximately 303 hectares (7 48 acres) of soils at Paducah are impacted by residual contamination. Long-term monitoring and restrictions prohibiting intrusive activities and residential development will control future use of these areas, consistent with the Records of Decision.
The Paducah site contains twelve unlined burial grounds (nine non-regulated and three permitted) which were used to dispose of radioactive and nonradioactive trash, equipment, and scrap metal. Consequently, the nature of the residual contamination found in the burial grounds consists of radionuclides, metals, PCBs, volatile organic compounds (VOCs), and other contaminants. The burial grounds occupy approximately 43 hectares (107 acres) within the DOE property boundary. The primary goal is to conduct cleanup or stabilization activities that will reduce contamination to levels allowing maximum reuse of the industrialized area with minimal institutional controls. As a result, DOE has divided the burial grounds into "principal threat" and "low-to-moderate threat" categories. The former category will be excavated to eliminate the sources of contamination, while the latter will be capped in place with a multi-layer cap. This cap will cover an estimated 1.2 million cubic meters (1.6 million cubic yards) of residual contamination.
Groundwater
Groundwater monitoring activities have begun under an interim Record of Decision. However, the degree of monitoring should decrease over time as remediation goals are verified. A network of wells monitor the migration of groundwater plumes and groundwater discharges to surface water. The Commonwealth of Kentucky requires a 30-year, post-closure groundwater monitoring and care period; however, due to the presence of DNAPLs, monitoring will likely be required for a longer period. DOE will continue to provide an alternate public water supply to affected residents as long as offsite DNAPL concentrations in groundwater are above maximum contaminant levels. Institutional controls, such as deed restrictions, are also planned, consistent with the site Land Use Control Assurance Plan and executed Records of Decision, to prevent improper use of contaminated groundwater onsite.
Surface Water/ Sediment
Surface water monitoring activities are ongoing, consistent with the Clean Water Act. However, the degree of monitoring may decrease over time with decreased industrial activity. In addition, institutional controls are in place including of postings, fences, and deed restrictions to protect against the improper use of surface water. For example, fish advisories are posted in Little Bayou Creek which runs through the Western Kentucky Wildlife Management Area.
Engineered Units
Capped landfills will require long-term monitoring, institutional controls, and ongoing maintenance. The closed landfills will require DOE monitoring for the foreseeable future. Institutional controls will be put in place to warn of contamination presence and prevent any subsurface disturbance of the areas. These caps will be maintained, monitored, and replaced in accordance with operation and maintenance schedules. Since contamination is left in place, institutional controls will be implemented, consistent with the site Land Use
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Paducah Gaseous Diffusion Plant
Control Assurance Plan, and CERCLA five-year reviews will be required. Warning signs, fences, and deed restrictions will remain in those areas containing landfills.
Facilities
Depending on sampling results after the final decontamination and decommissioning of the facilities, minimal institutional controls may be necessary. Deed restrictions or use limitations may be placed on areas with residual contamination. These restrictions will be consistent with the Land Use Control Assurance Plan and applicable Records of Decision.
2.3 Regulatory Regime
The site was placed on the National Priorities List in 1994, and the current environmental restoration program incorporates both RCRA and CERCLA requirements in a Federal Facilities Agreement. A Land Use Control Assurance Plan has been executed for the site, and the Records of Decision include a Land Use Control Implementation Plan. Waste management operations are conducted under RCRA, and waters discharged to the State are permitted under the Clean Water Act. In addition, all radiological operations are conducted consistent with DOE Orders.
2.4 Long-Term Stewardship Technology Development and Deployment
The problems at Paducah are very complex and will require deployment of the best science and technology available. A number of innovative technologies have been reviewed and utilized as part of the environmental restoration program, especially with regard to remediation of groundwater and DNAPL sources. An Innovative Treatment Remediation Demonstration program has been utilized to enhance the site groundwater feasibility study in addressing groundwater contamination. The Innovative Treatment Remediation Demonstration is in the initial stages of application to surface water contamination. Specific technologies include characterization of DNAPLs in groundwater through the use of innovative cone penetrometers and DNAPL sensors, in-situ groundwater remediation, and innovative air stripping.
One example of a new technology for in-situ groundwater remediation is the Permeable Treatment Zone. The Permeable Treatment Zone will be installed to treat contaminated groundwater in the southwest plume. This technology will involve construction of a subsurface wall through the injection of reactive treatment media. The system design is currently underway, with construction scheduled to start in the summer of 2000. If this demonstration is successful, its use, in conjunction with other source treatment technologies currently under evaluation, may prove to be considerably more efficient and effective than the existing groundwater pump-andtreat systems. In general, discovering and applying better and more efficient technologies will improve the efficiency and/or reduce the need for long-term stewardship activities.
2.5 Assumptions and Uncertainties
Most of the estimates of the extent of environmental contamination at the Paducah site are preliminary in nature. DOE has completed a remedial investigation of only one (groundwater) of the six areas (operable units) defining Paducah's environmental contamination. Consequently, estimates of the extent of soil, surface water, burial ground, facility, and site-wide cumulative contamination were developed with limited information. The majority of cleanup activities at the site will take place in the future, and current DOE estimates include a final completion date of 2010 for environmental remediation and limited facility decommissioning. The Commonwealth of Kentucky has expressed concern about the proposed PCB cleanup levels for surface soil and sediments. This issue is unresolved, and the outcome could have a significant impact on the amount of residual contamination
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National Defense Authorization Act (NDAA) Long-Term Stewardship Report
remaining in place. In addition, DOE completed an environmental health evaluation at Paducah in 1999 that highlighted the need for accelerating cleanup activities at the site. Finally, the disposition of contaminated facilities that are currently being used is unclear and will affect the amount and type of contamination or other hazards remaining on the site after cleanup is complete, as well as the costs for conducting long-term stewardship.
3.0 ESTIMATED LONG-TERM STEWARDSHIP COSTS
Estimated costs for long-term stewardship activities for the Paducah Gaseous Diffusion Plant are identified in the table below. The long-term stewardship costs represent monitoring surface water, groundwater, and capped landfills, as well as monitoring and maintaining engineered controls and enforcing institutional controls. The significant changes in costs below reflect replacement costs and decreasing monitoring costs. Replacement costs include cap replacements, water treatment component replacements, etc. The largest one ($59 million in FY 2061-2065) includes cap replacement, but smaller ones occur on different schedules (monitoring wells, piping, etc.). Monitoring costs include ground and surface water, which decrease over time as site conditions stabilize and less data needs to be collected. Generally, annual costs decrease between 2015 and 2070; however, between 2036 and 2070 the decreased costs are hidden by the replacement costs. For purposes of this report, long-term stewardship costs are shown until FY 2070; however, it is anticipated that long-term stewardship activities will be required in perpetuity.
Site Long-Term Stewardship Costs.(Constant Year 2?00 J)ollttrs) ..
Future land use at the Paducah site will include a combination of controlled access on 43 hectares (107 acres), mixed industrial-recreational use on 299 hectares (740 acres), and open space and recreational use on 1,042 hectares (2,576 acres). Within the industrial area, USEC will continue to use existing facilities to conduct uranium enrichment operations according to its lease with DOE. Several other inactive DOE facilities within the industrial area will either be decommissioned or reused for other private or public industrial purposes. Outside the fenced industrial area, the Kentucky Department of Fish and Wildlife will continue to use certain areas onsite as part of the West Kentucky Wildlife Management Area, unless the site redesignates the future use of this area. The remainder of the site will serve as a buffer zone around the industrialized area.
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Paducah Gaseous Diffusion Plant
For additional information about the Paducah Gaseous Diffusion Plant site, please contact:
John Sheppard U.S. Department of Energy, Paducah Site Office P.O. Box 1410 Paducah, KY 42001 Phone: 270-441-6804 or visit the Internet website at htto://www.bechteljacobs.com/pad/report.htm
