By Timothy Gardner
WASHINGTON (Reuters) -Holtec, the company seeking to reopen the Palisades nuclear reactor in Michigan, has found that corrosion cracks in steam generators “far exceeded” estimates, the U.S. nuclear power regulator said in a document published on Wednesday.
President Joe Biden’s administration this week finalized a $1.52 billion conditional loan guarantee to the Palisades plant. It’s part of an effort to support nuclear power, which generates virtually emissions-free energy, curb climate change and help meet rising demand for electricity through artificial intelligence, electric vehicles and digital currencies.
Palisades, which closed under a different owner in 2022, aims to be the first modern U.S. nuclear power plant to reopen after being completely shuttered.
A summary of an early September phone call between the U.S. Nuclear Regulatory Commission and Holtec, released Wednesday, said evidence of stress corrosion cracking in the tubes of both Palisade steam generators “far exceeds estimates based on previous operating history.” It was determined that 1,163 steam generator tubes showed evidence of stress cracking. There are more than 16,000 pipes in the units.
Steam generators are sensitive components that require meticulous maintenance and are among the most expensive units in a nuclear power plant.
Holtec wants to have the factory operational again at the end of next year. Patrick O’Brien, a company spokesman, said the results of the inspections were “not entirely unpredictable” as the standard system “layup process”, or procedure for maintaining the units, was not followed when the plant was closed.
But he said Palisades’ return is still on schedule and that Holtec wants to repair, not replace, the steam generators, which he said would last another 30 years once repaired.
“We expect the repair strategy will consist of ‘disconnecting’ approximately 300 pipes per steam generator that were connected to the original installation, and then addressing the pipes found during the inspections by plugging approximately 20% of the pipes that cannot be easily repaired and the pipes that cannot be easily repaired, the remaining 80% is sleeving, which is a common and proven repair strategy,” said O’Brien.
Holtec still needs permits from the NRC. “Holtec must ensure that the generators meet NRC requirements if the agency authorizes Palisades to return to operational status,” an NRC spokesperson said.
The NRC said last month that preliminary results of inspections “have identified a large number of steam generator tubes with indications requiring further analysis and/or repair.”
Problems with the steam generator can cause problems for nuclear power plants. Parts of the San Onofre nuclear power plant in California were closed in 2012 after steam generators leaked with a design flaw. Problems with new generators led to the closure of the factory in 2013.
