US-based Holtec Decommissioning International (HDI), a subsidiary of Holtec International, on 24 August reported decommissioning progress at the Oyster Creek NPP in New Jersey and the Pilgrim NPP in Massachusetts. At Oyster Creek, all fissile material is now on the Independent Spent Fuel Storage Installation (ISFSI) at the site. in less than five months, 2,433 used fuel bundles were loaded into Holtec Canisters and transported to the ISFSI. The peak transfer rate reached two and a half canisters a week, rapidly reducing radiation exposure (down by two-thirds at the last canister). The Reactor Building is now empty of any fissile material.
The Protected Area at the site has been reduced from approximately 150 acres to 6 acres with the authorisation from the Nuclear Regulatory Commission (NRC), making the task of the security workforce substantially easier and a more concentrated effort, HDI said. Risk management and innovative use of tooling has allowed Oyster Creek to perform reactor internal segmentation in parallel with moving fuel to dry storage. This has allowed loading and storage of three Greater-Than-Class C waste canisters. A systematic approach to site building demolition is ongoing at Oyster Creek using an innovative process that involves preparing the impacted buildings for open air demolition. Hazardous materials such as asbestos and lead are stripped out and components in the structures are decontaminated or incapsulated to ensure containment of contaminants.
Some of the structures already dismantled include the Air Ejection Off-Gas (AOG) Building, Torus Water Storage Tank, Radioactive Waste Storage Tank and a slew of structures originally scheduled for demolition in 2024 and 2025. Along with laser focus on the environment and crew dose minimisation, pragmatic decontamination efforts have afforded up to 95% of waste from the Torus Water Storage Tank and components such as the Hydraulic Control Units to be salvaged as scrap metal. “We are also endeavouring to recycle as many spare parts and components as possible. The site has completed the shipment of over 132,000 ft, over five million pounds, of waste to date,” HDI noted.
At Pilgrim, transfer of the used fuel in wet storage to the ISFSI is proceeding at the rate of two multipurpose canisters (MPCs) a week, which, like Oyster Creek, is an unprecedented rate in the industry. “We expect Pilgrim to be entirely defuelled by November of this year.”
Greater-Than-Class C waste, currently located in the dryer-separator pit, will be loaded into non-fuel waste containers following the fuel campaign and moved to the new ISFSI pad in December. In addition, the focus on risk mitigation and removal has led to a number of buildings and structures being removed earlier than expected.
The removal of the main emissions stack, a firewater storage tank and former plant operations support buildings, with careful attention to removing asbestos-bearing materials, has been completed, which has led to increased staging areas for waste removal, as well as enhanced security. This early staging has enabled earlier than planned shipping of some low-level radioactive materials to the disposal site in West Texas. More than 1.4 million pounds of material has been removed from the site including the 36 concrete shield blocks that used to cover the reactor vessel when in operation.
Commenting on the progress, HDI’s newly appointed President, Kelly Trice, said, “We should be proud that we have made great progress in both projects while meeting in full measure what I call the seven critical metrics of excellence, namely, minimal crew dose, no spread of contamination, no OSHA violation, no release to the environment, no worker injury, total schedule adherence and minimised quantity of waste for disposal.”