United States Nuclear Regulatory Commission - Protecting People and the Environment

UNC Naval Products

1.0 Site Identification

Type of Site: Complex Decommissioning
Location: New Haven, CT
License No.: SNM-368 Terminated
Docket No.: 070-00371 Former
License Status: Terminated License
Project Manager: Laurie Kauffman

2.0 Site Status Summary

The former United Nuclear Corporation (UNC) Naval Products facility is located in New Haven, Connecticut. The site is located near an industrial redevelopment area. Licensed material was used for research and fabrication of nuclear fuel components for the U.S. Navy. The radioactive material used at the site was primarily enriched uranium with lesser quantities of natural uranium, depleted uranium, and thorium. The work was performed in a large building containing chemistry laboratories and an assembly area. The U.S. Nuclear Regulatory Commission (NRC) released the site for unrestricted use and the site has since been utilized for commercial use.

The UNC Naval facility was operated by Olin Mathieson Chemical Corporation (Olin) from 1956-1961) and by UNC from 1961-1976. In 1960, the Atomic Energy Commission (AEC) issued Olin a special nuclear materials license (SNM-368) for the fabrication and manufacturing of reactor fuel components. The license was later transferred to UNC in 1961. In 1974, UNC transferred the radioactive materials from the facility in New Haven to a facility in Montville, Connecticut. Following the decontamination and decommissioning of the site, the NRC performed surveys New Haven facility and amended license SNM-368 to remove the New Haven facility from the license. Consistent with guidelines at the time, the site was released for unrestricted use. The NRC terminated license SNM-368 in 1994 after the UNC facility in Montville, Connecticut was decontaminated and decommissioned.

In the 1990's, NRC initiated an evaluation of terminated licenses to determine if the facilities that had been released for unrestricted use met the current NRC release criteria. Oak Ridge National Laboratory (ORNL) supported NRC in conducting the reviews. The UNC facility in New Haven was identified as a site for additional review. Results of sampling at the New Haven facility identified areas (beneath a concrete slab and trench inside the warehouse and inside a connected inactive sewer system) with enriched uranium concentrations in soil and sediment that exceeded the then current release criteria of 1.11 Becquerels/gram (Bq/g) (30 picocuries/gram (pCi/g)) established in 1981.

The NRC contacted the former UNC facility in New Haven, which was acquired by General Electric Corporation (GE) in 1997, concerning the elevated uranium contamination. GE agreed to undertake the remediation of the former facility. Later in 1998, GE informed NRC that the U.S. Department of Energy (DOE) had accepted financial responsibility for remediation costs. A characterization plan and a decommissioning plan was developed and approved by NRC in 1999. In 2008, the NRC re-approved the characterization plan and decommissioning plan, it also approved UNC's final status survey plan.

In April 2011, NRC met with UNC representatives and discussed initiating the remediation and decommissioning of the former facility and the release of the property and surrounding area for unrestricted release using the 1981 criteria.

In September 2011, UNC commenced remediation activities and, as of July 2012, had remediated most of the areas that were described in their decommissioning plan. During the clean-up activities, UNC identified additional soil under portions of the warehouse had exceeded the 1981 release criteria. UNC identified challenges to remediating these areas because they impacted structural supports associated with the warehouse. Because of this concern, UNC initiated a sampling program to determine the extent and magnitude of the uranium soil contamination in these areas. The updated sampling program applied the NUREG-1575, "Multi-Agency Radiation Survey and Site Investigation Manual [MARSSIM]." MARSSIM is a multi-agency consensus manual that provides information on planning, conducting, evaluating, and documenting building surface and surface soil final status radiological surveys for demonstrating compliance with dose-based regulations.

In July 2012, UNC submitted an addendum to their 1998 decommissioning plan that utilized a dose-based release criteria, also referred to as the derived concentration guideline level (DCGL), using the current version of the RESRAD computer code (Version 6.5) and using NUREG-1575, "Multi-Agency Radiation Survey and Site Investigation Manual [MARSSIM]." MARSSIM is a multi-agency consensus manual that provides information on planning, conducting, evaluating, and documenting building surface and surface soil final status radiological surveys for demonstrating compliance with dose-based regulations.

In May 2013, the NRC accepted UNC's site specific DCGLs. The DCGL is the radionuclide-specific concentration limit used during decommissioning to achieve the regulatory dose standard that permits the release of a property. The dose standard, according to Title 10, Code of Federal Regulations (CFR) 20.1402 (10 CFR 20.1402), "Radiological Criteria for Unrestricted Use", is 25 millirem (mrem) per year. For this site, the site specific DCGL that corresponds to the NRC 25 mrem per year dose standard is 573 picocuries (pCi) per gram (pCi/g) total enriched uranium. However, because the dose standard for the State of Connecticut is 19 mrem per year, UNC agreed with the CT DEEP to further reduce residual radioactivity, calculated a DCGL of 435 pCi/gram total enriched uranium, and committed to this DCGL. This DCGL is protective of human health and the environment and is below the 10 CFR 20 federal limit for unrestricted use.

On April 22, 2015, ORAU submitted their Final Report for the Independent Confirmatory Survey Results to the NRC. On April 28, 2015, UNC submitted their Characterization Survey Report to the NRC. In the report, UNC recommended that additional subsurface soil remediation beneath the utility trenches be performed. According to the characterization report, the extent of the contamination to be remediated is immediately around and under some drainage holes in the south trench.

In letter dated July 13, 2015, the NRC informed UNC that a review of the UNC's Characterization Survey Report had been completed and that the ORAU Final Report for the Independent Confirmatory Survey Results is publicly available. In the letter, the NRC agrees with the overall conclusions reached in UNC's Characterization Survey Report that additional remediation is needed at the site. The NRC also concluded, based on the work performed by ORAU, that the data generated by UNC's onsite laboratory should be considered semi-quantitative and should not be used to support decisions regarding unrestricted release, or substituted as final status survey data for areas that UNC determined do not require remediation.

On January 26, 2016, representatives from the NRC, DOE, UNC, and CT DEEP assembled in New Haven to discuss the next steps regarding the radiological remediation activities at the site. On March 31, 2016, UNC submitted a Supplemental Radiological Survey Plan to the NRC. In letter dated May 18, 2016, the NRC informed UNC that the NRC completed its review of the Supplemental Radiological Survey Plan.

As of mid-June 2016, UNC has been conducting characterization surveys of the additional areas described in UNC's Supplemental Radiological Survey Plan. On June 20-22, 2016, the NRC conducted a monitoring site visit at the facility. The purpose of the visit was to review UNC's activities regarding the Supplemental Radiological Survey Plan.

3.0 Major Technical or Regulatory Issues

See above.

4.0 Estimated Date For Closure


Page Last Reviewed/Updated Wednesday, August 10, 2016