The Office of Nuclear Material Safety and Safeguards Environmental Assessment, and Finding of No Significant Impact Related to the Approval of the Remediation (Decommissioning) Plan for the Formerly Licensed Union Carbide Corporation Facility (UCC), Lawrenceburg, Tennessee, License Nos. SNM-720 and SNM-724 (Terminated)

The U.S. Nuclear Regulatory Commission (hereafter referred to as NRC staff) is considering approval of the remediation (decommissioning) plan (DP) for the formerly licensed Union Carbide Corporation facility (UCC), Lawrenceburg, Tennessee (UCAR, 1998). This DP was submitted by UCAR Carbon Company, Inc. (UCAR) to NRC on August 19, 1998. UCAR is obligated to remediate the UCC site to meet the release criteria established in the Action Plan to Ensure Timely Remediation of Sites Listed in the Site Decommissioning Management Plan (hereafter known as the SDMP Action Plan) (NRC, 1992), and 10 CFR part 20 subpart E.

Introduction

On August 26, 1963, UCC was issued Special Nuclear Materials License No. SNM-724 (SNM-724), for testing equipment and nuclear fuels development. License No. SMB-720 (SNM-720), which authorized the possession of source material, was also held by the site. SNM-724 was terminated on June 4, 1974, and the U.S. Atomic Energy Commission (AEC) released the site for unrestricted use. SMB-720 was superceded by the State of Tennessee License No. S-5002-H8 and was terminated on August 28, 1975.

SNM-724 authorized possession of up to 500 grams (g) of fully-enriched (<94 percent) uranium for testing of equipment and processes in the Lawrenceburg Fuel Development Facility located at Highway 43 South, Lawrenceburg, Tennessee. On May 22, 1964, the license was amended to authorize possession of 150 kilograms (kg) of U²³⁵ to make graphite-coated uranium-thorium carbide particles and graphite-matrix fuel elements. The possession limit was increased to 475 kg on June 12, 1964.

By letter dated February 4, 1974, the UCC submitted “closeout” survey information and requested that SNM-724 be terminated and the facility be released for unrestricted use. On April 5, 1974, Region II performed a closeout inspection which was documented in their Inspection Report 70-784/74-1. Region II recommended that the license be terminated, and the facility be released for unrestricted use. By AEC letter dated June 4, 1974, SNM-724 was terminated and the UCAR facility released for unrestricted use.

In 1991, Oak Ridge National Laboratory (ORNL) was contracted by NRC, to review and evaluate all nuclear material licenses terminated by NRC or its predecessor agencies, since inception of material regulation in the late 1940s. One of the objectives of this review was to identify sites with potential for residual contamination, based on information in the license documentation. NRC evaluated the available survey data to determine if the information was sufficient to conclude that the site meets the existing guidelines for unrestricted use.

Radiological assessments performed at the UCAR facility and immediate vicinity have identified the presence of enriched and depleted uranium in soil excess of current radiological release criteria. Sampling identified soil/ sediments contamination in small areas around the processing buildings.

Volumetric contaminations were found to be above the release criteria in four areas around Building 10: (1) Soil surrounding the incinerator pad; (2) sediment in the manholes and cooling water tanks; (3) laundry sump tank; and (4) the surface layer of concrete flooring. A number of core samples as well as near surface samples were taken near the incinerator pad and the range for total uranium concentration was 1.33 to 3,655 pCi/g. The estimated average depth of the soil contamination is one foot resulting in a contaminated soil volume estimate of 500 cubic feet. Volumetric contamination above the release critieria was found in three areas in and around Building 5: (1) Sink trap; (2) concrete flooring; and (3) asphalt outside exit.

There was no indication of radioactive material above the release criteria beyond the former restricted area boundary in the ground water, settling basins, or former sanitary sewer system.

UCAR will be conducting remediation activities without a license, because its license was terminated in 1974. However, remediation will be performed in accordance with current regulations and release limits (UCAR, 1998).

Planned Decommissioning Action

Decommissioning of the UCAR facility shall comply with 10 CFR part 20 subpart E for unrestricted use (NRC 1997) criteria. The conduct of decommissioning and decontamination in compliance with these criteria provides adequate protection of the public health and safety and of the environment. In implementing the decommissioning plan, UCAR shall reduce residual contamination in soil to be below the NRC's unrestricted release criteria identified in 10 CFR part 20, subpart E (NRC, July, 1997). Soils which exceed the derived concentration guideline level (DCGL) will be removed and disposed of as low level radioactive waste.

General exposure rate levels will be reduced to levels below 5 microroentgen per hour (microR/hr) above background, measured at 1 meter (m) above the surface.

UCAR is proposing to conduct a final survey to demonstrate: (1) That uranium and thorium contamination levels in the soil are below the [25 millirem per year (mRem/yr)] DCGL's and (2) that exposure rate measurements are less than 5 microR/hr measured 1 meter above the surface. UCAR has committed to conducting the final survey in accordance with NRC approved site survey plan, as well as any applicable regulatory requirements.

The Need for Planned Action

The former UCAR facility is currently being used to manufacture non-radiological carbon products. The planned action is necessary to reduce residual contamination at the site to meet NRC's unrestricted release criteria.

Alternative to the Planned Action

The alternative to the proposed action is to take no action. A no-action alternative would mean the site would not be remediated now. Although there is no immediate threat to the public health and safety from this site, not undertaking remediation, at this time, does not solve the regulatory and potential long-term health and safety problems associated with having residual contamination on site. In addition, pursuing no action would delay remediation until some time in the future, when remediation costs could be much higher than they are today. Therefore, the no-action alternative is not acceptable.

Environmental Impacts of the Planned Action

Radiological impacts that could result from the remediation of the former UCC site are direct exposure, inhalation, and ingestion hazards to workers. These hazards could occur during decontamination of building surfaces and excavation and packaging of contaminated soil.

The radioactive material of concern at this site is enriched uranium. Gamma exposure rate measurements taken at locations throughout the site do not exceed background levels, with the exception of five locations near the incinerator pad. The highest radiation exposure rate detected near the incinerator pad is 26 microR/hr above background. Because the gamma exposure rate measurements are low, direct exposure to workers is not a significant radiological hazard.

UCC will implement an occupational exposure monitoring program to ensure that internal and external exposures are well below the regulatory limits, and to ensure that no individual exceeds a regulatory limit. Respiratory protection will be required for workers when airborne radioactivity could result in exposures above the administrative action levels set in the health and safety plan.

Although the potential for external exposure is low, UCAR will survey work areas for direct radiation whenever remediation is being performed. If dose rates exceed 5 mrem/hr, or if the RSO determines that worker exposure could exceed 10 percent of the regulatory limits found in 10 CFR part 20, subpart C “Occupational Dose Limits,” worker exposure will be monitored with thermoluminescent dosimeters.

UCAR has committed to implement a contamination monitoring and control program to detect and minimize the spread of contamination. Contamination monitoring will be accomplished by: (1) Conducting routine surveys; (2) use of access controls to prevent inadvertent personnel access to contaminated areas; (3) use of radiation work permits in areas where there is potential for workers to exceed 10 percent of the regulatory limits; (4) use of personal protection; and (5) employee training.

UCAR has committed to implementing a contaminant monitoring and control program to detect and minimize off-site effluent releases (UCAR, in its DP Section 3.3.4, 1998). The primary pathway for off-site release of radioactive material is airborne effluent. Inhalation and ingestion impacts will be minimized to the workers and public by controlling airborne material levels. Routine and special environmental monitoring will be conducted to detect, assess, and limit potential airborne releases. Air monitoring will be performed in work areas using Breathing Zone Air (BZA) samplers or high-volume air samplers. Administrative action levels at 10 percent of the regulatory limits for airborne effluents have been established. Investigations will be performed if administrative action levels are exceeded. No liquid wastes have been identified and none are expected.

Radioactive waste will be segregated from non-radioactive waste and stored in a controlled, fenced area. Radioactive waste will be stored inside, if possible. Otherwise, it will be stored outside and covered to protect against the weather. Radioactive waste will be packaged, labeled, manifested, and shipped in accordance with NRC and U.S. Department of Transportation requirements.

This site is being remediated to the criteria listed in 10 CFR part 20, subpart E for unrestricted use (NRC, 1997).

Agencies and Individuals Consulted

This environmental (EA) assessment was prepared by NRC staff. No other sources were used beyond those referenced in this EA. NRC staff provided a draft of the EA to Tennessee Department of Environment and Conservation, Division of Radiological Health for review. By e-mail dated May 1, 2000, the Tennessee Department of Environment and Conservation Division of Radiological Health agreed with NRC's conclusion that the proposed action will not have any significant effect on the quality of the human environment.

NRC contacted the U.S. Fish and Wildlife Service (FWS) to determine the potential impacts of the proposed action on threatened and endangered species near the UCAR facility. By letter dated September 10, 1999, the FWS informed NRC that the proposed action would have no impact on threatened and endangered species.

NRC staff provided a draft of the EA to U.S. Environmental Protection Agency (EPA) Region IV for review. By e-mail dated June 27, 2000, EPA did not have any comments on the proposed action. However, the EPA has noted the disagreement between the EPA and the NRC about the appropriate dose criteria to be used in decommissioning.

NRC also contacted the Tennessee State Historical Preservation Office to determine if any historical properties would be impacted by the proposed action. The Tennessee State Historical Preservation office informed the NRC, by letter dated May 2, 2000, that there are no National Register of Historic Places listed or eligible properties affected by the project.

Conclusion

During the decommissioning operation, radiological exposure to workers and annual average concentrations of radioactive material released off-site will be in accordance with Part 20 limits. UCAR has committed to perform remediation in accordance with an acceptable Health and Safety Plan. The Health and Safety Plan shall provide adequate controls to keep potential doses to workers and the public from direct exposure, airborne material, and released effluents as low as reasonably achievable.

NRC also believes that the remediation of the facility in accordance with 10 CFR part 20, subpart E for unrestricted use, adequately protects workers, members of the public, and the environment. The potential environmental impacts from the proposed action are not significant.

References

1. NRC, “Action Plan to Ensure Timely Remediation of Sites Listed in the Site Decommissioning Management Plan,” 57 FR 13389, April 16, 1992.

2. NRC, “Radiological Criteria for License Termination,” 10 CFR Part 20, Subpart E, 62 Federal Register 139, July 21, 1997.

3. NRC, “Multi-Agency Radiation Survey and Site Investigation Manual, (MARSSIM),” NUREG-1575, December 1997.

4. NRC, “Draft Manual for Conducting Radiological Surveys in Support of License Termination,” NUREG/CR-5849, June 1992.

5. Union Carbide Company Inc., “Remediation (Decommissioning) Plan for the Formerly Licensed Union Carbide Corporation Facility (UCC), Lawrenceburg, TN,” August 19, 1998.

Finding of No Significant Impact

NRC has prepared an EA related to the approval of UCAR's Remediation (Decommissioning) Plan, Terminated License No. SNM-724 and SMB-720. On the basis of this EA, NRC has concluded that the environmental impacts that would be created by the proposed action would not be significant and do not warrant the preparation of an Environmental Impact Statement. Accordingly, it has been determined the Finding of No Significant Impact is Appropriate.

The EA and the document related to this proposed action are available for public inspection and copying at NRC's Electronic Reading Room at http://www.nrc.gov/NRC/ADAMS/index.html.

FOR FURTHER INFORMATION CONTACT:

Rebecca Tadesse, Project Manager, Decommissioning Branch, Division of Waste Management, Office of Nuclear Material Safety and Safeguards. Telephone: (301) 415-6221.