Sigma-Aldrich (Fort Mims)

1.0 Site Identification

2.0 Site Status Summary

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Sigma-Aldrich Chemical Company (SAC) submitted a decommissioning plan (DP) for its Fort Mims Facility on October 22, 2008 (ML083010187). In a letter dated December 15, 2008, SAC requested to incorporate a phased decommissioning approach (ML083510270) into the licensee s decommissioning plan. On May 12, 2009, Region III concluded SAC DP and the phased approach acceptable and was approved for use (ML091330309). The first phase of decommissioning involved building remediation and decontamination to levels below the NRC s radiological unrestricted use limits. The licensee completed final status survey packages for all the building survey units. During a July 2009 inspection (ML092220491), the NRC has reviewed the licensee s final status survey of the building and performed confirmatory measurements. The NRC identified no deviations with SAC assessment of the building, concluding phase 1 of the decommissioning plan and SAC demolished the facility. In a letter dated December 15, 2008, Sigma-Aldrich Chemical Company requested to proceed with the collection of soil samples from areas around the Fort Mims Facility (ML083510259). On January 16, 2009, a letter from the NRC informed the licensee that staff had completed the review of the proposed Sigma-Aldrich, Fort Mims Facility, Open Land Soil Sampling and Analysis Plan, and had concluded that the technical approach described in the plan is acceptable, and that the NRC would evaluate the results of the survey conducted by the consultant during the review of the final status survey report. During the facilitys survey of the onsite soil, SAC identified localized surface and subsurface carbon-14 contamination above previous approved Derived Concentration Guideline Limits provided in the SAC DP. Currently, SAC is limited to NRC screening values provided in NRC guidance documents NUREG-1757, Consolidated Decommissioning Guidance for release of the site. However, since surface and subsurface carbon-14 residual contamination was identified during the final status survey above these approved release values, SAC is intending to request NRC approval for higher DCGLs for carbon-14 in soil for unrestricted release or conduct further remediation at the site. NRC review and approval of a license amendment will be needed prior to SAC completing either of these options.

The Sigma-Aldrich Company (SAC) Fort Mims facility was a two-story building consisting of approximately 20,000 square feet. The facility was located in Maryland Heights, Missouri on an approximately one-acre parcel in a commercial/light industrial park. SAC radioactive materials usage at the Ft. Mims site consisted of research and development activities as defined in 10 CFR 30.4, and storage, processing and use in the production of labeled compounds for distribution to authorized customers. The licensee used radioactive materials in specific areas of the building since 1975. The licensee ceased production activities at the facility on September 30, 2008. The radioactive materials significant to NRC decommissioning requirements used at the Fort Mims facility consisted of carbon-14 and hydrogen-3. The licensee was authorized at the time of cessation of activities to possess 800 curies of carbon-14 and 1000 curies of hydrogen-3. SAC submitted a decommissioning plan (DP) for its Fort Mims Facility on October 22, 2008 (ML083010187). NRC issued a letter on November 24, 2008, acknowledging receipt of the DP, and notifying the licensee that the DP had been accepted for technical review. On December 1, 2008, Region III staff contacted the responsible State of Missouri Health Department personnel to facilitate their participation in the review of the DP. The licensees decommissioning plan for the Fort Mims Facility has completed a 60 day comment period which was issued in the Federal Register (Federal Register Notice, Vol. 73, No. 249, Monday, December 29, 2008). The FRN commentary period ended February 27, 2009. No comments were received regarding on the DP and the NRC approved the DP on May 12, 2009.

3.0 Major Technical or Regulatory Issues

During the on-site outdoor soil survey, SAC identified localized surface and subsurface contamination above the NRC screening values. Since residual radioactivity was found to be higher than currently approved NRC screening values, SAC will need to either apply for site specific derived concentration guideline limits or remediate the soil.

4.0 Estimated Date For Closure