PILGRIM: ...one of the five worst performing reactors in the nation....

More problems at Pilgrim revealed

Systems that monitor seawater intake were lost during blizzard shutdown

Regulators and plant operator say the public was never in danger because of failed systems.

By Christine Legere
clegere@capecodonline.com Posted Feb. 13, 2015 @ 2:01 am

PLYMOUTH — 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 plant equipment would be swamped.

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

“The stationing of a plant employee at the water intake structure to monitor water levels was a compensatory measure,” Neil Sheehan wrote in an email. “Other examples of compensatory measures: Nuclear plants have utilized roving patrols to check for any indications of fire when fire suppression equipment is unavailable, or had security officers stand guard at specific locations if a motion detection system is out of service.”

Entergy Corp., the owner and operator of Pilgrim, 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 was not 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 hadn't reported the failure other than to state in an email, "equipment reliability was never challenged and the plant remained safe and in stable condition."

Both the NRC and Entergy have asserted 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 was restarted, with the nod from federal regulators, on Saturday.

A full report on what federal inspectors found won’t be available for 45 days.

"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 wrote. Emergency Action Levels, categorized as "unusual events", are tides above 13 ft. 6 inches.

"Water level at the highest point never challenged the 13-foot 6-inch unusual event declaration threshold," Burm wrote.

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,” according to Sheehan. “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.”

David Lochbaum, director of nuclear safety for the Union of Concerned Scientists, said the emergency diesel generators that took over when offsite power was lost need water cooling to prevent overheating damage.

“The service water pumps send ocean water to cool the emergency diesel engines and other safety equipment,” Lochbaum said. “Their role is why water level at the intake structure is monitored — if water level rises too high, operation of the service water pumps is jeopardized.”

Lochbaum added that nothing in reports about the shutdown has indicated there were any major impacts related to the loss of the water level instrumentation.

"There were several operational challenges, all of which the NRC is continuing to review," Sheehan wrote in his email. "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."

Diane Turco, a Harwich resident and co-founder of the Cape Downwinders said she is concerned about the plant’s performance during the storm. “This latest shutdown is very alarming,” she said, citing the multiple mechanical failures.

Turco added that such failures, coupled with human error, could “lead to a meltdown with consequences that would forever change the landscape of Massachusetts.”

Several citizens groups had asked Entergy and federal regulators to shut down the reactor in advance of the blizzard, based on forecasts regarding the severity of the storm bearing down on the region.

“Entergy should have taken the prudent approach in a severe coastal storm by shutting down while they had offsite electricity to do so in a safer and controlled manner,” Turco said.

Pilgrim is classified by federal regulators as one of the five worst performing reactors in the nation. There are currently 99 reactors operating in the U.S.

http://www.capecodtimes.com/article/20150213/NEWS/150219714/101015/NEWSLETTER100