Pilgrim Nuclear Power Station went back to producing electricity Thursday after a four-day shutdown to repair a massive malfunctioning valve.
The main steam isolation valve, one of eight designed to close quickly to prevent radioactivity from leaking into the environment during a nuclear incident, failed during testing Aug. 18.
It was part of the same valve system that caused the Plymouth-MA-based Pilgrim to shut down in August 2015.
In reaction to the latest shutdown, the Pilgrim Legislative Action Coalition sent a letter to federal regulators calling the valve failure “yet more evidence of Entergy’s unwillingness to maintain Pilgrim.”
“It’s obvious that Entergy’s safety culture is severely lacking and they consciously choose to jeopardize public safety, but Entergy’s job is to make money; it’s the regulator’s job to ensure that it does so safely,” said the coalition’s letter, written by member David Agnew.
The valve incident was not “a game-changer” that would lead to permanent shutdown, said Neil Sheehan, spokesman for the Nuclear Regulatory Commission (NRC).
“That’s not the way we view it,” he said. “We look at risk significance, and we still have increased regulatory oversight.”
Federal regulators have set requirements that must be met before a reactor can restart, said David Lochbaum, director of the nuclear safety program for the Union of Concerned Scientists. “Workers went through that checklist, with NRC inspectors spot-checking them, en route to the decision to restart Pilgrim.”
Sheehan said the faulty parts have been replaced.
“The company has shipped the removed parts to the valve vendor for further examination,” Sheehan said. “We will review those results as soon as they are available.”
Pilgrim, owned and operated by Entergy Corp., fell into the Column 4 performance category by the NRC in September, making it one of the worst-performing plants in the country. The category is one step from forced shutdown.
Based on federal inspections and reports, the 44-year-old plant, slated to permanently shut down in June 2019, continues to suffer from equipment problems and poor operator performance.
In May, workers discovered a boron panel used to prevent a nuclear reaction from occurring in the spent-fuel pool had deteriorated. Spent fuel rods ended up moved out of the area of the deteriorated panel.
Once it is shut down, Entergy should place Pilgrim into SAFSTOR, which allows the reactor and other buildings to remain where they are for up to 60 years. Spent fuel eventually will go in heavy dry casks on the property.
Sheehan said Pilgrim remained under close scrutiny. Two team inspections already have taken place this year and a third is expected by year-end, he said.
“We’ll bring in inspectors from other regions,” Sheehan said. “It will be a holistic view of everything the company has done.”