Ben Rogers, Rick McNutt and Preston McDaniel
Bechtel
Jason Darby
USDOE
ABSTRACT
The Department of Energy's Formerly Utilized Sites Remedial Action Program (FUSRAP) has remediated 23 sites contaminated with low levels of radioactive materials. While cleaning up these sites for commercial reuse, the FUSRAP team has developed and applied cost-effective methods for working in operating facilities, reducing waste volumes, using supplemental cleanup criteria, and recycling waste materials. For example, to verify that cleanup levels of underground piping met the specified criteria, an innovative in situ inspection instrument was used that minimized the impact of the inspection on an operating commercial production facility. At several sites, a rock crusher reduced rubble and building debris to soil-like material that can be beneficially reused, for a program savings of more than $4 million. Recycling efforts include the smelting and reuse of approximately 1million kg of radioactively contaminated scrap metal and an aggressive program for reclaiming and recycling materials from building demolition.
BACKGROUND
As many Americans know, the Manhattan Project was a secret program to develop an atomic weapon that would end World War II. Production facilities, chemical plants, and laboratories throughout the country processed uranium ore and other radioactive materials as part of that war-time effort. Forty-six sites in 14 states have since been identified as requiring remediation of low levels of radioactive contamination from activities associated with war-time and Cold War era efforts.
In the past, wastes from uranium processing were handled like waste from other industrial processes and were disposed of in ways thought at the time to be safe. Studies of potential health effects and environmental impact coupled with technological advances, especially in detection capability, have since identified that additional cleanup is required. The Formerly Utilized Sites Remedial Action Program (FUSRAP) was established in 1974 to identify, investigate, and clean up or control radioactively contaminated properties that were used to support the Manhattan Project and subsequent Cold War era nuclear research.
Administered by the U.S. Department of Energy (DOE), FUSRAP activities are authorized by the Atomic Energy Act of 1954, the 1984 Energy and Water Development Appropriations Act, and the 1985 Energy and Water Development Appropriations Act.
FUSRAP objectives are to
FUSRAP APPROACH TO SITE CLEANUPS
Among the different types of FUSRAP sites are DOE facilities, commercial facilities, vacant property, operating plants, and private residences. Although each site is different, there is a general approach FUSRAP uses to clean up contaminated sites. These steps include research and review of historical records, characterization of the site, engineering design and remedial action, and verification of site conditions and certification for future use.
There are generally two types of waste at FUSRAP sites. Much of the material resulted from processing ore to recover uranium and thorium. This type of waste is a "by-product" of the extraction process as defined by the Atomic Energy Act, Section 11e(2). Another type of waste containing very low levels of uranium from the machining of uranium metal is found at several FUSRAP sites; this waste is known as low-level radioactive waste.
CLEANUP STANDARDS
DOE Order 5400.5, "Radiation Protection of the Public and the Environment," and 10 CFR 835, "Occupational Radiation Protection," establish radiological protection program requirements. The DOE remedial action guidelines for alpha activity on surfaces are 5,000 dpm/100 cm2 average; 15,000dpm/100 cm2 maximum; and 1,000 dpm/100 cm2 removable. The DOE guidelines for radium-226, thorium-232, and thorium-230 concentrations in soil are 5 pCi/g when averaged over the first 15 cm of soil below the surface and 15 pCi/g when averaged over any subsequent 15-cm-thick soil layer below the surface layer, above background concentrations. For uranium, the DOE soil cleanup guideline is 100 pCi/g above background.
DOE Order 5400.5 provides criteria for release of previously contaminated materials for use without radiological restrictions. Supplemental limits to these criteria may be established if it can be shown that the less restrictive criteria will adequately protect public health and safety and the environment. For example, at the FUSRAP Chapman Valve and General Motors sites, effective use was made of supplemental limits produced from hazard assessments of site conditions and contamination levels to significantly reduce waste volumes requiring disposal. At Chapman Valve, the disposal volume was reduced by 95percent, and at General Motors the volume was reduced by 88percent by applying supplemental limits during site remediation.
CLEANUP METHODS
The design of FUSRAP cleanup operations is adapted to effectively address the specific conditions and requirements of each site. While some buildings are cleaned up to allow them toreturn to productive industrial uses, others are demolished and disposed of. Unique approaches have been devised for facilities that are fully operational, and other innovative techniques are applied to the efficient remediation of buildings that are not intended for any further use. Recycling and reuse of waste materials are especially important strategies for cost-effective site cleanup.
Reindustrialization
The Aliquippa Forge site is an example of a site that was cleaned up and returned to productive industrial use. Located in a mixed industrial/residential area in western Pennsylvania, the site was used in the late 1940s as a uranium rolling process facility for the Atomic Energy Commission. The site was decontaminated in 1950 to then-applicable guidelines. Additional radioactive contamination exceeding current DOE guidelines was identified in subsequent radiological surveys, and the site was designated for remediation under FUSRAP in 1983.
At the time of final site cleanup, the Aliquippa Forge site was owned by the Beaver County Corporation for Economic Development (CED). The site was abandoned and posed an environmental and financial burden for the community. CED's goal for the site was to return it to productive use in the local economy. A steel fabrication plant adjacent to the Aliquippa Forge site needed additional space for expansion, so FUSRAP worked closely with CED and the State of Pennsylvania to establish site cleanup guidelines and to remediate the site in time to meet the steel plant's expansion needs. CED identified this as a win-win opportunity for all concerned. However, if the site cleanup could not be completed in time, CED stated that "the Aliquippa Forge property may never be returned to productive reuse."
FUSRAP began the final cleanup of the Aliquippa Forge site in June 1993 and completed it in September 1994. The steel fabrication facility began using the site in January 1995 and today employs 60 people at the expanded facility that includes the Aliquippa Forge site. The president of CED stated that the responsiveness of FUSRAP personnel in quickly addressing problems as they arose was a major factor in the successful reindustrialization of the site.
Decontamination techniques used during the remedial action at Aliquippa included vacuuming, wire brushing, grinding, shot blasting, cutting and removal, and excavation. Approximately 900m3 of radioactively contaminated soil, building rubble and debris, and miscellaneous equipment was generated during the cleanup. Over 400m3 of the building rubble and debris was processed into a soil-like material using a commercial rock crusher. After verification that residual uranium levels in the crushed material were below the site cleanup criteria, the material was used as backfill onsite.
Demolition
The former Alba Craft Laboratory site is located in Oxford, Ohio, in a residential area. The laboratory machined natural uranium metal for the Atomic Energy Commission from October 1952 to February 1957. As a result, the equipment, buildings and grounds, and isolated areas ofsome nearby properties became contaminated with low levels of radioactivity. After the machining activities ended, the site was decontaminated in accordance with standards in effect at the time. The current owner of the Alba Craft building bought and renovated the building in May 1988 and began using it to support various business enterprises. The site was investigated in July 1992 at the request of DOE, and subsequent radiological surveys indicated that residual uranium materials exceeded current guidelines.
The former Alba Craft Laboratory building was composed of three cinder block structures built in sequence and joined to appear as one building. The roof consisted of metal trusses supporting wood decking with a tar-coated layer to provide waterproofing. Floors were concrete with typical crack control and expansion joints. Because of the poor condition of the building and the presence of radioactive materials throughout the building, a decision was made to demolish the structure during remedial action and remove all building debris and radioactively contaminated soil from the site. Approximately 2,100m3 of materials were packaged and shipped for disposal as low- level radioactive waste. To facilitate packaging and disposal of the waste, cinder block and concrete rubble from the building demolition was processed into a soil-like consistency using a commercial rock-crushing unit. To reduce the overall exposure of the labor force and to minimize the potential for offsite releases during demolition of the building and operation of the rock crusher, the interior of the building was surveyed to identify any "hot spots" on the overheads, floors, and walls. These areas were remediated before the building was demolished. Decontamination techniques employed included high-efficiency particulate air vacuuming, shot blasting, cutting, and demolition and excavation.
During the remedial action, engineering controls, administrative controls, monitoring, and personal protective equipment were used to protect workers and the public from potential exposure to radiation in excess of applicable standards. The primary exposure pathways for members of the public were inhalation and ingestion of radioactively contaminated airborne dust generated during soil excavation, demolition, and rock crushing. The potential for dust migration was minimized by using water sprays, erecting work fences, and placing waste in enclosed steel containers.
Because the Alba Craft site was located in a residential area, special considerations were made to keep the local community informed as the site remediation progressed. FUSRAP personnel attended city council meetings and special town meetings to discuss the cleanup process. In addition, site personnel had daily contact with neighbors to discuss site activities. For example, as a result of a weekly meeting with local citizens, site personnel visited a local school to ensure that noise from rock crusher operations did not interfere with upcoming outdoor field activities. Other efforts included conducting radiation surveys on request at the homes of former Alba Craft workers and educating citizens about Alba Craft site history and how site activities may have affected them. In general, the FUSRAP team made extra efforts to keep the local residents involved in the cleanup of a radioactively contaminated site in their town.
Cleanup of an Operating Facility
By combining up-front integrated planning, a risk-based hazard assessment, waste minimization, and an innovative technology at the General Motors (GM) site, over $1.5 million was saved overtraditional remediation methods. The GM site is a fully operational automobile component manufacturing facility with more than 6,000 employees. The plant operates 24 hours a day, so the remediation effort needed to be closely coordinated with plant personnel. Preliminary characterization data at GM indicated that residual radioactive contamination existed in underground pipes and drainlines. There were concerns over the potential for future exposures to uranium in the drainage systems. Preliminary cost estimates for complete remediation projected high costs for both remedial activities and lost manufacturing time at the GM facility.
A radiological hazard assessment indicated that removal of all the contamination exceeding cleanup guidelines would result in minimal dose risk reduction, because the remaining contamination was largely isolated in areas away from the workers. No regulations applied specifically to the waste oil, sludge, and water that would be generated during remediation. Commercial nuclear industry practices, relevant federal and state regulations, and a dose assessment were used as guidelines for developing a strategy for GM. Potential future doses and risks to workers could be reduced to safe levels through a modified remediation strategy, involving partial decontamination and grouting of drainlines, sumps, and manholes. A remediation strategy document was prepared and reviewed with the Michigan Department of Public Health and GM facility personnel; after all stakeholders agreed with this proposed approach, it was implemented.
A high-pressure water wash was used to remove the oils and sludges in the underground piping. This activity, coupled with the natural collection of water in the existing sumps over a long period of time, generated approximately 40,000L of radioactively contaminated wastewater. Disposal of the wastewater was handled in two ways. More than 6,000 L was used to solidify sludge and oil wastes. The remaining 34,000L was then processed through a multi-stage filtration process. Samples of the resulting filtrate were analyzed to ensure compliance with the guideline of 300 pCi/L of residual total uranium, and the wastewater was then disposed of at a local, licensed disposal facility. Approximately $178,000 was saved by using wastewater for sludge and oil solidification and filtering the remaining wastewater for local disposal.
An innovative technique was used to perform in-situ post-remedial surveys of the GM underground pipes and drain lines. The Pipe Explorer™, developed by Science and Engineering Associates, Inc., consists of a flexible, impermeable, tubular membrane material coiled inside an airtight canister. As air is blown into the canister, the membrane extends out of the canister and inverts. At the GM site, this mechanism was used to transport a high-sensitivity beta probe, specifically designed for this application, through designated pipes and drain lines; the probe obtained real-time data.
The chief advantage of this technology over more conventional means of deploying radiation detectors into pipes is the ability of the membrane to protect the detector from direct contact with the contaminated materials in the pipe under investigation. Thus, a true measure of the contamination by location in the pipe is possible, and the detector does not require decontamination after use. In addition, this system reduces the volume of radioactive investigation-derived waste, exposure to workers from the decontamination procedures, and the probability of damage to the detector. The waste for each surveyed pipe consists of used membrane measuring approximately 0.03m3, considerably less than would be generated by conventional underground pipe survey techniques.
The GM facility continued production during the remedial action, and the Pipe Explorer™ inspection process had minimal effect on ongoing operations. No modifications were necessary for access to the piping system. The resulting data from this survey showed that residual contamination in onsite drain lines was within approved cleanup criteria. Approximately $750,000 was saved by avoiding the excavation and disposal of approximately 1,100m3 of concrete, overburden, and pipe and by allowing the underground piping system to remain in place. An additional $750,000 was saved by avoiding a GM plant outage during the remedial action, for a total cost savings of $1.5 million.
The remediation and waste management cost savings at GM proved the value of obtaining early endorsement from regulatory agencies. This endorsement allowed the establishment of criteria that were protective of human health and the environment and were also technically achievable in a cost-effective manner. It is this type of early involvement with regulatory agencies and use of innovative remediation methods that will undoubtedly prove to be equally beneficial in future FUSRAP site cleanups.
Cleanup of an Abandoned Building
The Chapman Valve site is a 3,900-m2 building in Indian Orchard, Massachusetts. The site was designated for cleanup of low levels of residual uranium resulting from machining operations conducted in the late 1940s. Through an innovative dose-based remediation approach, which included the use of supplemental limits/hazard assessment, and various waste volume reduction techniques, the final project costs were reduced from the original estimate of $4.3 million to $2.0million, saving approximately $2.3million. Waste volumes were also reduced from the original estimate of 250m3 to 13m3, a reduction of approximately 95 percent.
The hazard assessment and supplemental limits were developed during the conceptual design of the remedial action and were included in the project baseline rather than being derived during and/or after the remedial action effort. As a result, the team was able to effectively sequence work actions to minimize rework and could focus efforts on providing a sound technical, cost, and schedule baseline. To apply the supplemental limits/hazard assessment approach, possible future use scenarios of the facility and the potential reuse of construction materials were modeled to determine human health effects of the radiological contamination. The site building was deteriorated and was to be demolished. An evaluation of naturally occurring radiation levels in building materials and solid waste showed that contamination at the site increased the natural (background) radioactivity found in brick by less than 23percent. Brick accounted for approximately 64percent of the mass of contaminated material, and it was found that supplemental guidelines allowing the material to remain in place would be protective of a future worker and the public and no remedial action would be required. Other supplemental cleanup limits for the horizontal surfaces of building trusses were also determined to be protective of a future demolition worker.
Volume reduction techniques included waste segregation, sampling, and surveying. Concrete and debris were surveyed to determine whether contamination levels were above criteria. The material below criteria was left onsite, with the property owner's concurrence. Paint removed from a crane was treated to reduce the content of leachable lead to below the limits set by theResource Conservation and Recovery Act and, with state and property owner concurrence, was also left onsite. Launderable coveralls were used rather than disposable protective clothing; this resulted in cost savings from recycling and reuse and reduced waste volumes. Finally, a personnel contamination monitor (PCM) was used at the access control point instead of the standard labor-intensive manual frisk. The standard manual frisk takes approximately five minutes compared to the one minute required for the PCM; over 60 hours of labor were saved over the eight-week life of the project.
RECYCLING/REUSE
Recycling is a primary waste management method because it conserves valuable resources and energy and reduces waste volume. The savings of valuable waste disposal capacity alone can offset the occasionally high cost of a recycling program.
Rock Crusher
FUSRAP has applied an innovative approach of using a commercially available, semitrailer-mounted rock crusher to reduce waste volumes requiring offsite disposal, for a cost savings so far of $3.5 million and a projected cost savings of an additional $500,000 this year. This approach provides a means of using volumetric release criteria to meet the site-specific cleanup guidelines for soil and debris based on DOE Order 5400.5. In many instances, contamination on debris consists of a thin layer, which is evaluated using surface release criteria. Reducing the debris to a soil-like material allows the use of volumetric release criteria. If the crushed material meets site volumetric criteria, and if release and beneficial reuse of the material are allowed by regulators, substantial cost savings are possible. Transportation and disposal cost savings for recycling crushed material onsite versus disposal offsite can be $750/m3 or more.
One example of savings with the rock crusher is at the St. Louis Downtown Site. The crusher was used to crush approximately 1,140 m3 of concrete and building rubble; the crushed material was then used as backfill onsite. The material contained an average of 3.1 pCi/g uranium-238, which was below the site soil cleanup guideline of 50 pCi/g. Savings of more than $784,000 resulted from reduced transportation, disposal, and backfill material costs.
Recycling at Colonie
FUSRAP recycling efforts include the recycling of radioactively contaminated metal at the Colonie Interim Storage Site (CISS) in New York. Manufacturing with depleted uranium and thorium at CISS resulted in contamination of the site building and equipment, including large metal machining and fabrication tools. A cost evaluation of remediation alternatives demonstrated that smelting the metal for recycling was preferable to direct disposal. Consequently, approximately 900,000kg of scrap was smelted into shield blocks for use in DOE research facilities.
In addition to steel recycling, approximately 3,000kg of depleted uranium andmetals containing depleted uranium was recycled. The material was pyrophoric and contained radionuclide concentrations in excess of disposal facility acceptance criteria. Thus, recycling saved significant treatment costs that would have been required to dispose of this material. The smelting and recycling of scrap metal at CISS met DOE's objective of recovery and reuse of valuable materials and provided significant waste volume reduction.
Another innovative recycling program at CISS resulted in respirator cartridge conservation. Workers were required to wear respirators as part of their personal protective equipment. During a typical day, a worker entered the building four times and used eight respirator cartridges. With an average of 45 employees, the annual cost of the respirator program was $610,200. After workers began to recycle their cartridges by wiping down, surveying, storing, and reusing them, FUSRAP realized an annual savings of $103,000. The cartridge recycling program also helped achieve FUSRAP's waste minimization goals by reducing the number of cartridges requiring disposal.
Fixed Price Subcontract Recycling
A recently implemented innovative approach to recycling has been the awarding of fixed price subcontracts, which specify that materials from building demolition must be recycled when practicable. This approach has been applied to scrap steel at two sites and to all materials generated during the decontamination and demolition process of a building at one site. At the Middlesex Sampling Plant in Middlesex, NewJersey, and at CISS, a subcontract was awarded for the decontamination and disposal of steel. The subcontractor removes the steel for decontamination and recycling or disposal. Approximately 450,000 kg of steel will be processed under this contract. At the Middlesex Sampling Plant, the process building demolition subcontract encourages the minimization of material going to disposal and emphasizes salvage and recycling to the extent practicable. Funds recovered by the subcontractor for scrap are to be used by the subcontractor to offset the cost of demolition services. The subcontractor's salvage and waste management plan calls for recycling steel, wood, brick, masonry, block, concrete, mercury, and fluorescent tubes.
The brick, block, sheetrock, concrete, and glass will be crushed to a size of 10 cm or smaller so that the material cannot be reused for building a habitable structure (i.e., cannot be reused for its original purpose). Before release of the waste for recycling, FUSRAP will sample and analyze the material to confirm that DOE volumetric release criteria are met.
RECOMMENDATIONS/FUTURE ACTIONS
FUSRAP will continue to expand its use of proven and innovative ways to reuse and recycle materials and reduce costs while accomplishing safe and environmentally protective remediation. Reindustrialization opportunities will continue to be evaluated to identify realistic future use scenarios, establish protective cleanup levels, and work with local communities to return facilities to productive reuse. Opportunities for recycling are continually evaluated to reduce waste and the costs of disposal and transportation. Future plans also include adopting a moreformalized process for early incorporation of pollution prevention and waste minimization into the planning process. Greater emphasis will also be placed on these measures through training and additional program guidance.