The US Connecticut Department of Energy and Environmental Protection (DEEP), along with partners at the federal, municipal, and community levels, and the private sector, on 9 July announced completion of remediation activities at the former United Nuclear Corporation site in the Newhallville neighbourhood of New Haven.
The site was utilised by the US Department of Energy (DOE) to conduct research and make nuclear fuel components for the Navy from the mid-1950s until 1974, during the Cold War. Although environmental clean-up was conducted at the time the facility closed, the Nuclear Regulatory Commission (NRC) reviewed the situation in recent years and determined that additional work was needed. Final remediation work at the site began in October 2019 and concluded in late 2020.
The completion of remediation work at the site was an example of different stakeholders working together for a common purpose. DOE, NRC, DEEP, General Electric (GE), the Connecticut Department of Public Health (DPH), the City of New Haven, Newhallville community organisers, and the current site owner all played key roles in this accomplishment.
The final remediation work consisted of deconstructing the buildings on-site, as well as concrete foundations, utility trenches, and sub-slab structures and basins, and excavation of underlying soil to achieve acceptable regulatory requirements. Clean-up operations were conducted to minimise the generation of airborne dust, and air monitoring activities were conducted throughout the process. Nearly 10,000 tons of waste materials were removed from the site, and transported to facilities in Alabama and Utah without incident. Where possible, non-regulated construction debris, such as concrete and steel, was recycled locally. Deconstruction was conducted by Stamford Wrecking Company, with oversight by Arcadis, an environmental consulting firm.
Radiation professionals from DEEP and the NRC provided oversight of the remediation work, reviewing work plans to ensure regulatory compliance; and conducting independent confirmatory analyses to confirm that the site was remediated to state and federal standards. These analyses included analysing numerous soil samples taken from the site and conducting a scan of the site using radiation detection instruments to ensure the soil met state and federal radiological criteria.