Corrosion cracking at the Palisades NPP exceeds previous estimates, NRC, according to the US Nuclear Regulatory Commission (NRC). Stress corrosion cracking in steam generators at the Palisades Nuclear Plant “far exceeded estimates based on previous operating history”, NRC noted.
Holtec International plans to restart the 800 MWe nuclear generating station in Michigan, which began commercial operation in 1971 and ceased operations in May 2022. Holtec aims to upgrade the plant and bring it back online and to produce power until at least 2051. However, a lot of work remains to restore and revive the plant.
According to a summary of a call between NRC and Holtec, NRC identified 1,163 of the 16,000 steam generator tubes with indications of stress cracking, which “far exceeded estimates based on previous operating history”. The call summary has been made public by NRC.
Holtec spokesman Patrick O’Brien told Reuters the results of the inspections “were not entirely unpredicted” as the standard system “layup process”, or procedure for maintaining the units, was not followed when the plant was shut down. An NRC spokesperson told Reuters: “Holtec must ensure the generators will meet NRC requirements if the agency authorises returning Palisades to operational status.” NRC explained that potential maintenance was not unexpected as the previous owner did not carry out any repairs when shutting the facility down.
The reactor was removed from service by owner/operator Entergy in May 2022, and defueled, and its sale to Holtec completed in June 2022. However, Holtec then announced that it was applying for federal funding to allow restart of the plant. In April, DOE through its Loan Programs Office (LPO) announced the offer of a conditional commitment of up to $1.52bn as a loan guarantee to restart the plant. This has now been confirmed.
Palisades would represent the first ever recommissioning of a retired NPP in the US. The plant could restart as early as August 2025, according to a July update from an NRC official. While Holtec is fully focused on reopening the facility, the steam generators that have been identified as cracked will require detailed and expensive maintenance. “Holtec must ensure the generators will meet NRC requirements if the agency authorises returning Palisades to operational status,” an NRC spokesperson said.
