Expert: Pilgrim shutdown a 'near miss'

Plant's owner says claim is 'unfounded and irresponsible'

By Christine Legere
Posted Mar. 25, 2015

"Pilgrim Nuclear Power Station in Plymouth will be placed on the Union of Concerned Scientists' list because of a shutdown of the reactor that occured during a blizzard on Jan. 27. Merrily Cassidy/Cape Cod Times

PLYMOUTH — The Union of Concerned Scientists’ top nuclear expert says the forced reactor shutdown at Pilgrim Nuclear Power Station during the Jan. 27 blizzard was risky enough to make his organization’s annual “near miss” list.

David Lochbaum, director of the organization’s Nuclear Safety Project, said Pilgrim wasn’t near meltdown, but the multitude of mechanical difficulties that occurred after offsite power to the plant was partially lost are cause for concern.

“There are many, many steps before a core meltdown, but they took a few steps down that road,” Lochbaum said about Pilgrim. “In a perfect world, you don’t want to go down that path at all.”

An Entergy spokeswoman protested Lochbaum's characterization of the Jan. 27 shutdown.

“These claims are completely unfounded and irresponsible," Lauren Burm wrote in an email. "The shutdown occurred safely as plant operators were reducing power in response to the onset of a historic storm. During the storm, conditions were stable and there was never any threat to the safety of plant workers or the public."

On Jan. 27, Pilgrim’s problems began with partial loss of offsite electrical power out in the plant’s switch yard. Station response was complicated by the failure of a diesel-driven air compressor, leaking of a safety relief valve used to help depressurize the reactor; failure of one of the manually-operated safety relief valves; and failure of a "high pressure coolant injection system," which then leaked an inch of water onto the floor.

Sump pumps couldn’t clear it, since all nonvital functions were shut down.

“Those events had the potential to lead to core damage by a factor of 10,” Lochbaum said, which means the risk of that damage occurring would be 10 times greater than on a "normal everyday."

Nuclear Regulatory Commission officials sent a special federal inspection team to the plant shortly after the shutdown, a move that triggers inclusion by the Union of Concerned Scientists on its "near miss" list.

“Most shutdowns don’t have the NRC boarding a bus and heading for the plant,” Lochbaum said about the level of concern at the federal agency.

But NRC spokesman Neil Sheehan said the risk was still low.

“Keep in mind the risk is one in a million per year,” Sheehan said about the typical risk of an event causing serious damage to the reactor's core. “At 10, you’re still talking about an extremely rare event.”

Sheehan said eight special team inspections were performed in 2014. Only two of those were related to unplanned reactor shutdowns, which happen an average of about 38 times per year.

The situation is evaluated by risk analysts before a team is sent.

“It has to meet some clear-cut criteria for us to send a special inspection team in,” Sheehan said. “We’re not talking the risk of reactor meltdown. We’re talking about the erosion of safety margins. Anytime we see that sort of increase in risk, we take a closer look.”

Federal nuclear officials are expecting Entergy to submit a mandated follow-up report with more details in the next few days.

The NRC inspection team will issue its findings, along with any recommended enforcement, by the first week in May.

“The team conducted its exit interview at Pilgrim last Friday,” Sheehan said.

Lochbaum’s organization publishes an annual list of “near misses” at nuclear power plants and details why each was included on the list. Last year, Pilgrim wasn’t on the list, which included 11 plants.

In 2011, Pilgrim was on the list twice: One of those involved security-related issues which the NRC does not discuss.

"The second event at Pilgrim in 2011 involved the operators losing control of the reactor during an attempted start-up, forcing automatic protective safety features to step in and shut down the reactor," Lochbaum said.

Both times, special inspection teams were sent.

Burm said Entergy has invested nearly $500 million into safety-related upgrades since 2000.

"Safe operations are the foundation of all work done at Pilgrim," she wrote. "Whether in a temporary shutdown or operating at full capacity, Pilgrim has and always will operate safely."

When asked by the Times if he and the Union of Concerned Scientists are anti-nuclear power, Lochbaum said they do not oppose plants that perform well.

“Our criteria is set by government regulations,” Lochbaum said. “The regulations define what is safe. If you’re below that, we’re not happy. If you’re above, you won’t hear a peep from us.”

"UCS is pro-nuclear safety and anti-nuclear disaster," he later wrote in an email. "Our commentaries and reports are true to this position, highlighting good nuclear safety outcomes and spotlighting bad ones."



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