Dec. 27, 2011
WOODS HOLE, Mass. — The Pilgrim Nuclear Power Station in Plymouth, Mass., was shut down on Dec. 26 because a safety relief valve was leaking steam. It was the reactor's second shutdown in two months due to mechanical problems.
Nuclear Regulatory Commission spokesperson Neil Sheehan said that Monday's shutdown was prompted by steam leaking from a valve that is there to assist the reactor's cooling system by discharging steam and preventing over-pressurization.
"Safety relief valves serve a very important function," Sheehan said. "If they were to have an accident and they needed to dissipate the steam that's generated by the reactor very quickly, these valves would come into play. So when these are not functioning the way they should, they either have to fix them or shut down until they are able to get that addressed."
It is not known how much steam leaked from the valve before the shutdown, Sheehan said. However, he said the public was not at risk, as the facility's other safety relief valves and safety systems remained available.
Sheehan did not have information about when the reactor would be ready to power back up.
Pilgrim was shut down on Nov. 17 to repair a leaking steam pipe that could not be isolated. It was back running at full capacity 10 days later. And this past May, the plant experienced an automatic emergency shutdown when workers failed to follow proper procedures. That event led to the NRC mandating additional oversight of Pilgrim.
Pilgrim has been operating for the past 39 years and is currently seeking a 20-year license renewal from the NRC — an effort that has been questioned by Mass. Attorney General Martha Coakley's office as well as local activists. The reactor contributes 677 megawatts to the New England energy grid, enough to power nearly 700,000 homes.
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