Pilgrim nears temperature cap
Reactor at reduced power as winds, warm water challenge cooling operations.
PLYMOUTH — Northeasterly winds have been pushing warm water released from Pilgrim Nuclear Power Station’s reactor beyond a breakwater and into a sheltered area where 500 million gallons are drawn each day to cool operational systems, according to a spokesman for plant owner-operator Entergy Corp.
Bay water being used for cooling may not exceed 75 degrees under Pilgrim’s federal operating license, and the warm water migrating to the intake area is driving temperatures toward the federal cap.
If the intake water goes above 75 degrees, operators must begin shutdown procedures.
Pilgrim operators have lowered reactor power to between 42 and 50 percent since Sunday to avoid that scenario.
“They’re using reduced power to mitigate that,” said Neil Sheehan, spokesman for the Nuclear Regulatory Commission. “By reducing it to 43 percent, it reduces cooling demands.”
Pine duBois, executive director of the Jones River Watershed Association and well-known steward of Cape Cod Bay, said Pilgrim’s current problem is not surprising.
“The bay is pretty warm right now,” duBois said. “The ocean is being impacted by global warming, and the Gulf Stream current is warming and coming closer to our shore.”
That northeasterly wind would not only direct the hot outfall water into the intake area, it would drive debris from the bay into the screens used to prevent it from entering the cooling system, duBois said, creating one more challenge for plant operators.
Entergy spokesman Patrick O’Brien confirmed the “thermal backwash” used to clean the screens is currently being done, even though it had been done about a week ago.
The Pilgrim plant has been in operation since 1972, but it experienced intake temperatures at its allowed limit for the first time in its history in 2013. Temperatures exceeded the limit again in 2015 and 2016.
Several nuclear reactors are grappling with temperature problems, Sheehan said. Some have requested and been granted increases to the temperature limit for water being taken in.
“Pilgrim contemplated it,” Sheehan said. The company ultimately did not request a temperature increase. “They continue to be challenged at this time of year by warm water,” he said.
David Lochbaum, director of the nuclear safety program for the Union of Concerned Scientists, said it is likely too late for Pilgrim to ask to lift the temperature cap, as the plant is set to shut down permanently in June.
“Millstone and Turkey Point are nuclear plants using the same ocean as Pilgrim for cooling water,” Lochbaum wrote in an email. “Years ago, the owners of Millstone and Turkey Point noticed the rising ocean temperature and took steps for NRC to approve increased cooling water temperature limits.”
It has been a tough year financially for Pilgrim, and the extended power-down will not help.
The plant has been in full shutdown for 55 days since Jan. 1. Pilgrim generates an average of about $1.1 million in gross revenue per day and about $569,000 after all the bills are paid, based on figures from ISO-New England and data from SNL Energy, a data and analysis resource for the utility industry.
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