02-26985. U.S. Department of Agriculture, Ames, IA; Environmental Assessment and Finding of No Significant Impact; Notice of Availability

AGENCY:

Nuclear Regulatory Commission.

ACTION:

Environmental Assessment (EA) and Finding of No Significant Impact (FONSI) for remediation of radioactive waste burial site, U.S. Department of Agriculture, Ames, IA.

SUMMARY:

The U.S. Nuclear Regulatory Commission (NRC) is announcing the availability of the EA and FONSI for the remediation of the radioactive waste burial site at the U.S. Department of Agriculture facility in Ames, IA.

SUPPLEMENTARY INFORMATION:

The Nuclear Regulatory Commission is considering amending the United States Department of Agriculture's Byproduct Materials License No. 19-00915-03 to authorize excavation and remediation of the radioactive waste burial site located at its facilities in Ames, Story County, Iowa.

1. Introduction

The U.S. Department of Agriculture (USDA) submitted a request dated August 16, 2002, for an amendment to Nuclear Regulatory Commission (NRC) License No. 19-00915-03. The licensee requests approval to decommission a radioactive waste burial site located on its property in Ames, Iowa. USDA proposes to excavate the site and retrieve the buried radioactive waste for shipment to a commercial waste disposal site in accordance with the procedures contained in that and subsequent submissions. The licensee has retained Cabrera Services, Inc., an NRC licensee (License No. 06-30556-01), to perform the decommissioning and remediation of the site.

The burial site is approximately 0.25 acre (0.1 hectare, 11,000 ft ² 2, 1000 m ²) in the National Animal Disease Center (NADC) located on USDA property in Ames, Story County, Iowa. In addition to the burial site, about 80 NADC research laboratories and other facilities are located on the 320 acre (130 hectare) NADC property. The licensee buried radioactive material and associated chemical waste (mostly liquid scintillation media) at the site from 1971 (when 10 CFR 20.304 authorized burial of defined radioactive waste) until January 1981 (when 10 CFR 20.304 was withdrawn). The waste buried is typical of that generated by bench scale research with radionuclides and includes such items as lead pigs, vials, pipettes, packaging materials, gloves, absorbent paper, test tubes, scintillation vials, carbon filters, and liquid scintillation counting fluid. The licensee estimates that the volume of buried waste is 40 cubic yards (30 m ³) containing 250 millicuries of hydrogen 3, carbon 14, and nickel 63. The waste was placed in double plastic (polyethylene) bags and then buried in 16 separate pits, each approximately 6 feet (1.8 m) deep. The pits lie along a straight line over a distance of about 300 feet (91 m). Each burial is covered by about 3 feet (0.9 m) of soil.

2. Purpose and Need for the Proposed Action

The licensee plans to construct additional research facilities at NADC that may disturb and/or cover part or all of the burial site. Removal of the buried waste will facilitate the construction activities and will avoid future contamination of the soil and/or groundwater with radioactive and/or chemical waste.

There is currently no evidence of soil or groundwater contamination with radioactive material or hazardous chemicals. However, in addition to the fact that it will be necessary to disturb at least part of the burial during the planned construction, the waste may deteriorate with the passage of time, resulting in future soil and/or groundwater contamination. Therefore, the licensee plans to remediate the site prior to construction of the new facilities. The licensee is also coordinating the remediation activities with the U.S. Environmental Protection Agency (EPA) because the buried waste includes hazardous chemicals. USDA applied for and obtained from EPA approval for remediation of the burial site.

3. Proposed Action

The licensee plans to remove the buried waste and any associated contamination, properly dispose of all waste generated and release the burial site for unrestricted use prior to construction activities.

The licensee performed an extensive review of available records and interviewed appropriate personnel to determine the locations, structure of and identity of the radioactive materials present in the burials. Records indicate that hydrogen 3, carbon 14, sodium 22, sulfur 35, chlorine 36, potassium 40, chromium 51, nickel 63, iodine 125, iodine 131, and radium 226 were used at the facility during the period when the burials were made. However, sulfur 35, chromium 51, iodine 125, iodine 131, and sodium 22 have relatively short half-lives and were eliminated from consideration during the planning of the decommissioning because the quantities were small and have undergone decay for more than 10 half-lives. The licensee's records indicate that potassium 40 was purchased only once in 1967, in an exempt amount, and, therefore, it was also not considered further. Similarly, chlorine 36 was screened out because it was acquired in solution and, according to both available records and interviews with users, waste containing chlorine 36 was disposed of to the sanitary sewer at the time of its use. The licensee concluded that all radium 226 was in the form of a single one millicurie sealed source. It is not clear if that source was disposed in a burial, but, if it is present, it should be possible to locate it during dose rate surveys of the site that will be performed before and during the excavations or during the sorting and repackaging of the waste for disposal. The licensee has concluded that the buried radioactive waste contains less than 250 millicuries of radioactive material (hydrogen 3, carbon 14, and nickel 63). The waste was buried in double plastic (polyethylene) bags in 16 separate pits, each approximately 6 feet (1.8 m) deep. These pits lie along a straight line about 6 feet (1.8 m) apart over a distance of about 300 feet (91 m). There are about 3 feet (0.9 m) of cover soil over each pit. The licensee used these conclusions in planning the removal of the burials.

In November 1989 the licensee opened the first burial pit. Observation and soil samples taken at that time did not indicate leakage of radioactivity or chemicals from the bag that was buried in the pit. The licensee performed additional monitoring in 1996 by drilling six wells approximately 15 feet (4.6 m) deep around the burial site. Analyses of soil samples taken as recently as April 2000, from these wells did not indicate presence of any volatile organic compounds. In September 2002, water samples from the wells did not indicate any radioactivity above background. Based on this information and observations of the burial in 1989, the licensee has concluded that the plastic bags containing the waste are largely intact which should facilitate removal of the waste.

The licensee plans to retrieve the buried waste by excavating the burial site in three stages. The first stage will be accomplished using a mechanical excavator to dig a trench 8 feet (2.4 m) to 12 feet (3.7 m) wide and 3 feet (0.9 m) deep approximately 300 feet (91 m) long that will include all 16 pits. The second stage will involve digging a narrower trench symmetrically located within the first trench. This will be accomplished by carefully removing soil in 2-4 inch ( 5-10 cm) layers to reduce the risk of puncturing or tearing the buried bags. The third stage will begin when the top of a bag or other evidence of waste appears. Then excavation will be performed by hand (to minimize the potential for rupture of bags or the spread of waste or contamination) until each bag or all identifiable waste is retrieved. A one-foot layer of surrounding soils will be removed from all surfaces of each pit following the extraction of the bags and/or waste.

After all visible waste and the additional foot of soil is removed, the pits will be surveyed for radioactive contamination following an approach developed using the guidance provided in NUREG 1575, “Multi-Agency Radiation Survey and Site Investigation Manual” (MARSSIM). The licensee will collect samples from the surface and at a depth of about 1 foot (30 cm) below the bottom and behind the walls of each pit. Each sample will be analyzed for radioactivity and compared to the decommissioning goals selected by the licensee (described below). The measurements will be made with a Minimum Detectable Activity (MDA) of about 50% of the goal.

The surface sample data will be compared to the decommissioning goal. The subsurface sample data will be compared to a background reference area to demonstrate that residual contamination is limited to the first 15 cm of soil, if any is present at all. The sampling procedure is designed to assure the decommissioning goals are applied in a fashion consistent with the limitations placed on the published screening values which are the basis for approval of the goals. Additional soil, in 6 inch layers, will be removed if the analytical results indicate contamination in excess of the goals in surface samples or in excess of background in the subsurface samples. If the licensee's surveys indicate the presence of significant soil contamination, sufficient characterization will be performed to support the development of custom derived concentration guidelines (DCGLs) for the site.

The NRC published screening values for radioactive contamination in soil based on an annual dose limit of 25 millirems in the Federal Register (64 FR 68395-96, December 7, 1999 and 65 FR 37186, June 13, 2002). The licensee used EPA's Generic Soil Screening Guidance, the computer code RESRAD and a dose limit of 15 millirems/year in order to choose decommissioning goals that would be acceptable to the NRC as well as the EPA. The values selected by the licensee are less than the published screening values and, therefore, are acceptable to the NRC for surface soil. As discussed above, the licensee's procedures are appropriate to assure that the goals are applied in accordance with published guidance.

All excavated waste will be stored temporarily in an enclosed sealand container after visual examination to verify integrity of each bag. The licensee has procedures for gathering and containing any waste which may escape from the bags. There will be a closed tent within this container fitted with a High Efficiency Particulate Air (HEPA) filtration unit to control potential airborne contaminants. Each bag or container of waste will be opened within the tent and the waste material will be segregated, characterized in accordance with approved licensee procedures, applicable regulations and waste disposal facility acceptance criteria. All waste, including any contaminated soil, will be properly packaged and shipped off site for disposal at an appropriate commercial waste disposal facility. The traffic generated by the shipment of the radioactive waste is expected to be a small fraction of the traffic for the entire site. The licensee estimates less than 10 truckloads with no more than three trucks at the site at any one time. The licensee has appropriate procedures for controlling the exposures of workers and releases to the environment during these operations.

Following the removal of all waste and contaminated soil, any additional necessary final status surveys will be performed in accordance with the guidance in NUREG 1575, “Multi-Agency Radiation Survey and Site Investigation Manual” (MARSSIM). Based on the actual survey results, the licensee will prepare and submit for approval a ground water monitoring plan for a specified time period. The licensee expects to complete the decommissioning of the site late in 2002, submit a Final Status Survey Report and request approval to release the site for unrestricted use.

4. Alternatives to the Proposed Action

The licensee considered four alternatives with regard to the burial site. One alternative is to take no action. Under this alternative monitoring and control would continue, but decommissioning actions would not be performed. Therefore, the risk of exposure to existing chemical and radiological material would not be reduced, and would be expected to increase over time. In addition, the licensee would either be forced to relocate the planned building or to take control measures similar to those proposed for the decommissioning during construction. The impact of relocating the building would be additional design and construction expenses along with delays in construction. If the building is not relocated, the additional control measures during construction would have impacts similar or greater than those expected during the remediation.

A second alternative is to implement additional containment and institutional controls. This might involve covering the burial site with additional soil cover and additional institutional and engineering controls to help ensure that the waste material remains contained within the burial site. This alternative would prevent future use of the burial site location. The licensee concluded that this alternative does not adequately control risks and does not meet the requirements of regulatory agencies (EPA and the NRC). The main impacts of this alternative are permanent loss of use of the land area and the additional cost for containment and institutional controls.

A third alternative considered by the licensee involves excavation of the buried waste and transporting it to an on-site storage facility until disposal off site. The licensee estimated that this alternative would take over 5 years to implement. The licensee did not consider this alternative further because of the impacts of additional costs, additional construction on the site and the loss of use of the location for a protracted period of time.

The preferred alternative is removal of the buried waste and any contaminated soil followed by prompt and appropriate disposal, as described above. This alternative allows productive use of the area of the burial site and prevents future contamination of soil and possibly groundwater with radioactive material and hazardous chemicals.

5. Affected Environment and Justification of the Action

The burial site is about 0.25 acre (0.1 hectare) of the 320 acre (130 hectare) NADC research complex in Story County, within the incorporation limits of Ames, Iowa. There are more than 80 buildings and other facilities in the research complex. The city of Ames had a population of approximately 51,000 according to the 2000 census. All people in the vicinity of NADC are served by ground water, either from the Ames municipal wells or from private wells. The nearest potable municipal well is located approximately 1.8 miles (2.9 km) from the waste site. The nearest private residence is 0.8 mile (1.3 km) from the waste site.

The NADC research complex is bounded on the east by Interstate Highway 35, on the south by the USDA's National Veterinary Services Laboratories (an additional 153 acres (62 hectares) of USDA property), on the west by Dayton Road and on the north by agricultural lands. Land use in the vicinity of the NADC is commercial to the south, residential to the west and agricultural to the north and east.

Topography in the vicinity of NADC is gently rolling with a divide which causes approximately one third of the facility's drainage to flow towards the southwest with the rest of the drainage flowing generally northeast. The drainage flows overland and percolates into the soil. It can be intercepted by storm sewers, roadside ditches, or it can reach the Skunk River about one mile (1.6 km) southwest of the burial site. The Skunk River is not used for drinking water. Near the burial site, the ground water flows west with a slight southwest trend. The ground water flow is somewhat independent of surficial water flow. Soil of the site is mainly composed of clay loams and loams.

Four major aquifer types exist in Story County: Alluvial aquifers, bedrock aquifers, buried channel aquifers, and drift aquifers. The upper bedrock aquifer underlies all of Story County. Overlying the upper bedrock aquifer are surficial aquifers and surface streams. The upper bedrock aquifer and surficial aquifers produce approximately 75 percent of the county's public water supply. Drift aquifers, which are not present in the vicinity of NADC produce the remaining 25 percent. A buried channel aquifer provides drinking water in the Ames area. Only the upper bedrock aquifer is present under NADC and is approximately 150 feet (48 m) beneath the ground surface. There are approximately 50 feet (15 m) of essentially impermeable clay between the aquifer and the ground surface at NADC. Therefore, the burial has presented and the planned decommissioning activities will present, little danger to the potable water supply.

While the burial site is unlikely to affect potable water supplies, the upper local groundwater table may be less than 5 feet (1.5 m) beneath the surface during the rainy seasons of the year. Water levels in the monitoring wells around the burial site have been measured at less than 4 feet (1.2 m) beneath the ground in early spring. It is possible that the buried waste may at times have been be surrounded by the ground water. Over time contact between the buried waste and ground water might make contamination available to surface plants and foraging animals. However, recent sampling of these wells found no radioactivity above natural background in the water.

The vegetation on the site is primarily introduced grasses and alfalfa and most of the undeveloped land on the NADC is utilized for animal foraging and pasture. Animals that inhabit the site are moles, deer mice, red fox, striped skunk, raccoon, badger, and an occasional whitetail deer. Birds such as horned larks, killdeer, vesper sparrow, and ring necked pheasants would likely inhabit the site. No unusual, threatened or endangered species of vegetation or wildlife are known or expected to occur on the site. There are approximately 15 acres (6.1 hectares) of wetlands in a ravine approximately one-half mile to the east of NADC.

Analyses of soil and water samples from the monitoring wells and one of the burial pits indicate that the buried waste material has not left the burials and has not had an adverse impact on the surrounding environment. However, the licensee plans construction activities near the burial site and these activities will change the underground profile of the burial site. If the waste remains buried, the leakage may occur during construction or in the future. Leaking material could be transferred to soil and local plants and thence to foraging animals. Due to the planned disturbance of the area and the possible future deterioration of the waste it is prudent to remediate the site now. This will avoid the spread of contamination into the environment and possibility of exposure of members of the public.

6. Environmental Impacts of the Proposed Action and Mitigating Measures

The licensee and its contractors have committed to comply with all pertinent environmental requirements to protect human health and the environment during the implementation of the proposed action. The licensee will follow appropriate standards set by the U.S. Occupational Safety & Health Administration (OSHA) to ensure worker health and safety, and will obtain all necessary permits from the local and state authorities.

Impacts of decommissioning activities such as increased noise and traffic are not expected to be significant because of the small area to be remediated and the fact that only a few pieces of construction equipment will be used to avoid dispersal of the waste during remediation. The burial site is currently fenced and not available to general access. The exclusion area and congestion in the area will increase somewhat during remediation, but the time of remediation is short (4 to 6 weeks) and there is adequate space to reroute traffic and other activities. The main environmental impacts are expected to be disturbance of the ground surface, the possibility of local soil erosion and the collection of precipitation in open excavations leading to the generation of potentially contaminated water.

The licensee's procedures for the excavation of the site are described in detail in a letter dated August 16, 2002, with enclosed Work Plan. The procedures are adequate to prevent or control soil erosion and the spread of radioactive and chemical contamination. Since the amount of radioactivity is not large and is most likely well contained, the risk of contamination spread is low and can be controlled by the licensee's procedures. Berms will be built around the excavated pits and soil storage areas to prevent water from getting into these areas and to control erosion. During excavation and screening dust will be controlled by misting with water and excavated soil will be covered to prevent it from becoming airborne. Wash water and precipitation will be collected, stored in tanks, sampled and disposed of in accordance with applicable regulatory requirements.

The licensee has developed procedures to control personnel exposures and to prevent the spread of radioactive contamination to other areas during and following excavation. A boundary (Construction Zone) will be established to mark the areas where excavation and remedial activities will be performed. Access to the areas within this boundary will be controlled by the use of temporary fencing with clearly defined access points. A Radiological Control Zone will be established within the Construction Zone to isolate the areas that could become radiologically contaminated. All areas will be appropriately posted.

Airborne contamination surveys and other appropriate radiological surveys of the soil and the trench surfaces will be made during and after removal of each soil layer. These surveys will determine if there was leakage into the soil from the waste and ensure that workers are not exposed to radiation from any unexpected source.

Spread of contamination from the burials would likely be by surficial or underground water currents. Such a spread of contamination is expected to be directed downward or laterally and, therefore, radioactive contamination is not expected in the top layer of soil. Therefore, the soil excavated during the first and second stages (top layers) will be spread in a 6-inch layer on polyethylene sheeting of at least 10 mil thickness in a designated lay down area for screening and potential segregation. The plan is to use as much of this soil as possible for backfill of the trench. Soil excavated during the third stage (after the tops of the bags become visible) will be loaded into intermodal containers and covered with tarps. This soil will be more extensively sampled for contamination. All soil contaminated in excess of the of the decommissioning goals will be shipped to an approved disposal site.

After radiological surveys confirm that the site meets the decommissioning goals, the burial site will be filled with the excavated non-contaminated soil and, if necessary, additional clean fill. The site will either be incorporated into a major construction project or appropriately vegetated. All waste and any contaminated soil removed will be transferred to a commercial burial site. The licensee will perform final radiological surveys of the site to ensure that the site meets NRC criteria for release for unrestricted use.

All contaminated items or material, including the equipment used in the excavation, will either be decontaminated in a designated area near the burial site, or disposed of in accordance with licensee's approved radiation safety procedures.

The licensee's procedures to initiate, accomplish and complete the remediation of the burial site adequately address concerns about the protection and radiological safety of members of the public and workers, the environment, and natural resources in the area.

7. Endangered Species and Historical Site Review

No unusual, threatened, or endangered species of vegetation or wildlife are known or expected to occur on the NADC property. There are no habitats of endangered species on the NADC property. Wetlands near the NADC property are not involved in the remediation activities. These conclusions were confirmed in discussions with the U.S. Fish and Wildlife Service.

The Iowa State Historical Society has reviewed the site and planned activities and concluded that it is unlikely that any areas of historical significance are involved.

8. Agencies and Persons Consulted

Scott Marquess, U.S. Environmental Protection Agency. The EPA is reviewing the proposed remediation, has approved the project and will monitor the implementation of the remediation activities.

Daniel McGhee, State of Iowa, Department of Public Health. The Department of Public Health representative indicated knowledge of the site including the research uses of radioactive material, supports the removal of the burial site and had no special concerns about the removal.

Wayne Fisher, U.S. Fish and Wildlife Service. Contact discussed in Section 7.

Daniel K Higginbottam, Iowa State Historic Preservation Office. Contact discussed in Section 7.

9. Sources Used

Letter from U.S. Department of Agriculture to USNRC, Region I, dated August 16, 2002, requesting approval to remediate burial site at National Animal Disease Center, Ames, IA, with enclosed Work Plan (ML022330227).

Engineering Evaluation and Cost Analysis for USDA National Animal Disease Center, Revision 1, Final, dated August 14, 2002 (ML022690109).

Letter from Cabrera Services to USNRC, Region I, dated August 20, 2002, providing documents used in historical assessment of burial site (ML022390595).

Letter from USEPA, Region VII to UDSA, dated August 6, 2002, regarding Engineering Evaluation and Cost Analysis for NADC, Ames, IA (ML022270115).

Fax from USDA to USNRC, Region I dated September 11, 2002 providing additional information (ML022550516).

Fax from Cabrera Services to USNRC, Region I, dated October 3, 2002 which encloses letter from Iowa State Historical Society to USDA, date July 22, 2002 (ML022890418).

10. Finding of no Significant Impact

Pursuant to the National Environmental Policy Act of 1969 (NEPA) and the Commission's regulations in 10 CFR part 51, the Commission has determined that there will not be a significant effect on the quality of the human environment resulting from the excavation and retrieval of the buried waste and transfer to an off site waste disposal facility. Accordingly, the preparation of an Environmental Impact Statement is not required for the proposed amendment to Byproduct Material License No. 19-00915-03, which will authorize decommissioning of the burial site. This determination is based on the foregoing Environmental Assessment performed in accordance with the procedures and criteria in 10 CFR part 51, “Environmental Protection Regulations for Domestic Licensing and Related Regulatory Functions.”

The amendment request by United States Department of Agriculture and related documents are available for inspection and copying for a fee at the Region I Office, 475 Allendale Road, King of Prussia, PA 19406. The documents may also be viewed in the Agency-wide Document Access and Management System (ADAMS) located on the NRC website at www.nrc.gov.

Dated at King of Prussia, Pennsylvania, this 16th day of October, 2002.

For the Nuclear Regulatory Commission.

John D. Kinneman,

Chief, Nuclear Materials Safety Branch, Division of Nuclear Materials Safety, Region I.