MA Nuke Shuts Down During Blizzard

Thursday, February 19, 2015 @ 11:02 AM gHale

During the blizzard that socked Plymouth, MA, the weekend of Feb. 14 and 15, officials shut down the Pilgrim nuclear power plant to avoid a repeat of problems that occurred during the Jan. 27 storm that caused a 12-day shutdown.

“We are following plant procedures to prepare for a potential loss of offsite power or the grid’s inability to accept the power Pilgrim generates,” Lauren Burm, a spokesman for Entergy Corp, the owner and operator of the plant.

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The 680-megawatt plant shut down automatically at 4 a.m. Jan. 27 after an electrical connection used to feed electricity to the grid ended up interrupted amid the worsening storm.

It reconnected to the grid last Feb. 7. During the Jan. 27 blizzard, the Pilgrim Nuclear Power Station experienced a series of problems that prompted operators to rely on backup systems as the reactor shut down following a loss of offsite power.

But when a generator powering instruments that measure seawater levels in the plant’s intake bays failed to start, the backup plan was to send a worker outside to a shed to eyeball the situation and make sure tides weren’t driving levels so high that water would swamp plant equipment.

There was nothing out of the ordinary in the seemingly simple fix for the problem-plagued nuclear reactor, according to a Nuclear Regulatory Commission (NRC) spokesman.

“The stationing of a plant employee at the water intake structure to monitor water levels was a compensatory measure,” said NRC spokesman Neil Sheehan.

Entergy promptly reported other glitches that occurred during the storm to the NRC as required – including the loss of consistent offsite power and subsequent reactor shutdown; the switch to two onsite generators; the failure of the high-powered cooling injection system needed to cool the reactor; and the subsequent failure of one of four valves used as backup to the cooling injection system.

But the failure of the generator powering systems that measure seawater intake did not end up reported by Entergy but rather discovered by federal inspectors on site a few days after the storm. Entergy then filed a belated report, on Feb. 5, with the NRC.

Entergy spokeswoman Lauren Burm would not comment on why the company did not report the failure other than to say, “equipment reliability was never challenged and the plant remained safe and in stable condition.”

The NRC and Entergy have said the public was never at risk during the plant’s shutdown. Federal inspectors were at the plant for a week following the January storm. The reactor restarted Feb. 7.

“The sea water levels at the intake bay did not rise above typical levels at any time during the storm,” Burm wrote about the intake measurement system failure.

High tide level in the intake bays is typically 8 to 9 feet above mean sea level, Burm said. Emergency Action Levels, categorized as “unusual events,” are tides above 13 ft. 6 inches.

The NRC classifies the system that measures water intake as non-safety-related. “It is not needed to operate the plant and is only there to provide control room indication for intake level,” Sheehan said. “This instrument is not safety-related, nor does it need to be safety-related, since the operators can go and physically observe intake level locally.”

“There were several operational challenges, all of which the NRC is continuing to review,” Sheehan said. “But to suggest the plant came close to an emergency that threatened either the plant workforce or the general public is simply off the mark.”

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