This post is a part of a series on Near Misses at U.S. Nuclear Power Plants
On January 27, 2015, Winter Storm Juno knocked out both of the 345,000 volt transmission lines connecting the Pilgrim nuclear plant in Plymouth. Per design, the reactor automatically shut down when the second offsite power line was lost. When equipment problems and operator errors complicated the intended response, the NRC dispatched a special inspection team to the site to investigate what happened (and didn’t happen).
The plant’s owner submitted a written report to the NRC about the automatic shut down and ensuing complications on April 1, 2015.
The NRC’s report by the special inspection team was issued on May 27, 2015. It provides a timeline for major actions during the days it took to restore power to the plant.
UCS developed a slideshow based on the NRC’s report. The slideshow ends by describing the eight violations of safety regulations identified by the NRC’s special inspection team. Those concluding slides are shown below.
Pilgrim’s owner cannot control the weather. Hence, Winter Storm June and the loss of power it caused at Pilgrim is not the owner’s fault.
But Pilgrim’s owner can – and must – control whether the equipment and workers can respond to challenges to successfully mitigate the event.
This event revealed too many inexcusable problems at Pilgrim. For example, the operators restarted the Reactor Core Isolation Cooling (RCIC) system, but failed to open the valve supplying cooling water to the system’s components. It’s the second step in the procedure, but the operators failed to follow it and open the valve. And the control room received two separate alarms indicating that the valve alignment might be wrong, but the operators responding to the alarms did not notice that the cooling water valve was closed. And as the slideshow details, poor operator performance caused the RCIC system to be automatically turned off, necessitating their flawed restart attempt.
This is not the first time in recent history where the operators at Pilgrim responded poorly. Fission Stories #59 described an attempted restart of the reactor in May 2011 from a refueling outage. They flubbed basic, routine steps so badly that the reactor essentially tilted – shutting itself down before the bad-acting operators inflicted any more harm.
The NRC must compel this plant’s owner to significantly improve the performance capability of the operators at Pilgrim. Their performance is way, way below the industry average. Somebody has to be the worst performer by definition. But it’s past time for somebody else to be the worst.
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