Nuclear safety expert seeks data about Pilgrim incident

By Christine Legere
The Cape Cod Times

Posted Jul. 1, 2016 at 12:11 AM
Updated Jul 1, 2016 at 12:13 AM 

PLYMOUTH – A well-known nuclear safety expert is looking for more information from the Nuclear Regulatory Commission regarding a report that both emergency diesel generators at the Pilgrim Nuclear Power Station had been out of commission at the same time for a short period in April while the reactor was operating at full power.

David Lochbaum, director of the Nuclear Safety Program for the Union of Concerned Scientists, questions how long the plant had been running with no emergency generators, which provide a default power source to safely shut down the reactor, maintain safe shutdown conditions and operate all essential systems if primary and secondary power sources have failed.

The Pilgrim plant can continue to operate for only 24 hours with both generators down, under conditions of its license. If one isn’t back online within that time frame, the reactor must go into cold shutdown, Lochbaum pointed out in his email.

Entergy, Pilgrim’s owner-operator, filed an event report on the April incident with federal regulators on June 9. The report is required because it was “a condition that could have prevented the fulfillment of the safety function of a system needed to shut down the reactor and maintain it in a safe shutdown condition, remove residual heat and mitigate the consequences of an accident,” according to the report.

The document said workers had removed one of the plant’s two diesel generators from service for planned maintenance at 7 p.m. April 11. More than 25 hours after shutting down the generator, a worker noticed water leaking across the floor “at 130 drops a minute” from a pipe coupling on the generator believed to be still operable.

Workers determined the leak was caused by stress corrosion and pronounced the generator inoperable, leaving the plant with no working generators.

Workers fixed the leak and put the diesel generator back in service shortly before noon April 12.

Meanwhile, Mary Lampert, a Duxbury resident and director of Pilgrim Watch, said she believed the situation occurred because of aging equipment and lack of vigilance.

“It’s the same old story: Entergy running the reactor on the cheap – generating not required backup power but trouble for us and themselves,” wrote Lampert in an email.

While Lampert noted Pilgrim workers used to operate on eight-hour shifts, which would have resulted in three checks of the diesel room daily rather than the current two, Patrick O’Brien, speaking for Entergy Corp., said the change to 12-hour shifts occurred in the 1990s, before Entergy bought the plant. O’Brien added that Pilgrim still maintains a full staff of 650 employees.

“The plant’s operations professionals maintain scheduled rounds of all protected equipment when another system is out of service, and the procedures in place ensure the plant maintains safe operations,” O’Brien wrote.

‘‘Proper procedure was followed, and there was no impact on public health or worker safety. At the time, the plant had access to its other back-up power source – the station’s blackout generator – as well as the preferred source, off-site power.”





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