The controversial nuclear power plant, which has a poor safety record, was shut down March 6 to allow the repair of a leak in one of five water heaters that feed liquid into the reactor, according to Neil Sheehan, a spokesman for the US Nuclear Regulatory Commission.

Patrick O’Brien, a spokesman for Entergy Corp., the Louisiana-based company that owns the 46-year-old nuclear plant, said in a statement that the date “for when the plant returns to service is currently undetermined.”

Pilgrim Nuclear Power Station remained shut down Friday for the 18th straight day as the Plymouth facility awaited the replacement of a transformer that delivers electricity to its auxiliary power system if the plant’s main generator goes offline, officials say.


The plant remained offline through the March 13 nor’easter that brought high winds and heavy snow accumulations across the region, Sheehan said. Plymouth saw about 16 inches of snow during that blizzard, according to the National Weather Service in Norton.

After that storm, which knocked out all offsite electricity helping to power the plant, Entergy became aware of issues with the startup transformer, and test results this week showed that it would be necessary to replace it, Sheehan said.

The transformer is on the plant’s non-nuclear side, Sheehan said, and has no effect on nuclear safety at the facility. He said Nuclear Regulatory Commission inspectors have monitored testing of the defective transformer and will continue to oversee its replacement.

Pilgrim has been shut down about 10 times since the beginning of 2015 for maintenance and weather-related causes, Sheehan said. This is Pilgrim’s second shutdown of the year, he said, following a six-day outage in January after power lines that connect the plant to the electric grid failed during an earlier storm.

An internal Nuclear Regulatory Commission memo made public in late 2016 said inspectors had found a “safety culture problem’’ at the plant and that employees appeared to be “overwhelmed” and struggling to improve the facility’s performance.


The commission said, though, that the lengthy shutdown doesn’t present any danger to the public.

“We do not have any current safety concerns,” Sheehan said in an e-mail. “The plant is in a safe shutdown condition.”

Activists who oppose the plant, however, said the shutdown is further evidence that the facility is in a state of disrepair that threatens lives.

“The power plant has produced no energy for more than half the month of March. This is like a plumbing supply store closed because their own sump pump failed,” said Donald Barton, an activist who has called for Pilgrim’s shutdown. “It’s just a ludicrous and very dangerous situation that needs intervention.”

Diane Turco, director of the group Cape Downwinders, said the failure of a transformer following the water heater leak and other breakdowns should alarm residents and regulators.

“It’s not just one piece of equipment; it’s multiple pieces of equipment, and that’s something that could cause a core meltdown,” she said. “And if that happens, we lose all of Eastern New England.”

The power station is scheduled to close permanently in May 2019.

Jeremy C. Fox can be reached at jeremy.fox@globe.com. Follow him on Twitter @jeremycfox.