This is the Environment Report. I’m Rebecca Williams.
The federal agency that regulates nuclear power plants released more information about a leak over the summer at the Palisades plant near South Haven. The plant has one of the worst safety ratings in the U.S. after a number of problems last year. (You can learn more from our timeline of the problems at Palisades over the past two years.)
Michigan Radio’s Lindsey Smith has been following developments at Palisades. There’s been at least three water leaks at Palisades this summer. Lindsey, remind me which leak this was?
Lindsey: “This one is arguably the most important because water was leaking from the actual vessel that holds the nuclear reactor. It’s important that water covers the reactor completely. The Nuclear Regulatory Commission doesn’t allow any leakage like this so the plant shut down in August to fix it.”
Rebecca: It has been fixed, right? Do we know what caused it?
Lindsey: “Yeah, the leak has been fixed and Palisades is operating. We know that the leak was coming from a tiny hole in one of the reactor’s control rod drive mechanism. Plant operators can move these control rods in or out of the reactor vessel to control the rate of the reaction.
But we still don’t know what the root cause of the hole was. During a briefing Monday afternoon, NRC branch chief Jack Giessner noted that there was a similar leak from the control rod drive mechanisms – he calls them CRDMs – in the past.
“All the CRDMs were replaced in 2001. That was one of the drivers for why we did an special inspection. We said ‘hey, it’s only been 11 years and we have another through-wall leak.'”
It’s not clear how quickly the hole formed. Palisades operators believe it formed slowly over eight years. The NRC says that’s possible but believe it could have been only two years. We won’t know that for another three or four months.”
Rebecca: What else did Giessner say about the leak?
Lindsey: “He estimates that up to 10,000 gallons of water leaked from the reactor vessel over 33 days. He says the radioactive water was contained in the building and then processed like normal radioactive liquid and there were no safety concerns for the public.
I asked Giessner how well he thought Palisades responded to the leak. Because an independent safety assessment done last spring said there was a “repeated emphasis of production over safety.”
“I think they were prompt to shut down. I think the NRC’s assessment when they were getting ready to start up we weren’t happy with their performance in that case and we took specific action.”
Giessner says the NRC had to prompt Palisades to do a more thorough inspection before restarting the plant.”
Rebecca: So what’s the bottom line here?
Lindsey: “The bottom line here is that Palisades is under more scrutiny because of the recent safety problems. The NRC wants to be more transparent about what’s going on there. So that’s why the agency took this unusual step of releasing preliminary results of its inspection.
We’ll get the final results of the inspection in a few months. But in the meantime, the NRC is in the middle of a different, even bigger inspection. This one is to follow up on the poor safety culture among workers at the plant that led to Palisades’ poor safety rating. The results of both of these inspections will impact the safety rating, but we won’t know the final results for a while.”
Rebecca: Thanks Lindsey. Lindsey Smith is Michigan Radio’s west Michigan reporter.