Several nuclear power plants in the path of Hurricane Sandy, the "superstorm" that devastated parts of the East Coast last week, endured the hurricane-force winds and storm surges without significant impact, the Nuclear Regulatory Commission (NRC) has said.
Last week, circulating-water pumps at Salem Unit 1 in Lower Alloways Creek Township, N.J., were affected by the storm and taken out of operation, but they were not damaged. According to NRC Senior Public Affairs Officer Diane Screnci, when several of the pumps were no longer able to perform their function because of high river levels and debris in the waterway, the plant operators followed procedures and manually shut down the reactor.
Once the reactor was off-line, the plant operators followed procedures and used back-up systems, including atmospheric steam dump valves, to deal with residual heat. The plant was safely shut down.
Oyster Creek nuclear power plant in Forked River, N.J., did not, at any point, lose the ability to pump cooling water from the intake canal, but it did have a concern that motors for the pumps could be rendered inoperable if water levels in the water intake structure rose too high, Screnci said. “That did not happen, however. Also, plant personnel stationed a portable pump at the intake structure as a precaution in case the pumps were impacted. As such, the ability to continue to keep the fuel assemblies in the spent fuel pool cool was at no point compromised.”
Oyster Creek, which declared an alert on Monday night of the storm, when the combination of a rising tide, wind direction, and storm surge caused water level to rise in the intake structure, exited the alert two days later. The plant also regained offsite power, which it had lost during the storm. (Emergency diesel generators provided back-up power in the interim.)
Three nuclear power plants shut down during the storm: Indian Point 3 and Nine Mile Point 1 due to grid disturbances, and Salem Unit 1 due to high water level and debris affecting the circulating water pumps. “Preparations are underway at each of those sites to return them to service,” Screnci said. The plants that reduced power, Millstone 3, Limerick Units 1 and 2, and Vermont Yankee were at or near full power by last Thursday.
Screnci said on Nov. 1 that “there’s a feeling of normalcy” in the NRC’s Region I—a jurisdiction that covers Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, and Washington, D.C.—which bore the brunt of the storm last week.
“The NRC and the nuclear plant operators worked hard to assure that the plants were safe over the weekend. In all, dozens of NRC staff members spent days preparing for and responding to the storm. While our thoughts are with those who have lost so much to the storm, we are satisfied that we did our jobs to respond quickly and effectively to the challenges the storm posed to the nuclear power plants we regulate,” she said.
According to Scott Burnell, an NRC public affairs officer, U.S. nuclear plants are typically prepared to weather hurricanes and other storms. “Every U.S. nuclear plant has a list of severe weather conditions that require it to shut down as a precaution. But because these plants are built robustly, and built to withstand the expected forces of nature in the area, they don’t necessarily have to shut down in the face of severe weather. It all depends on their specific criteria,” he said.
Burnell listed a number of nuclear reactors that had endured storms even more intense than Sandy:
• In 2005, the Waterford 3 plant in Louisiana remained safe after Hurricane Katrina knocked out the plant’s connection to the electric grid. Waterford ran its safety equipment on emergency diesel generators and remained safe once it reconnected to the grid four days later.
• In 2004, both reactors at the St. Lucie site in Florida remained safe after Hurricane Jeanne knocked out the plant’s grid connection. The plant’s staff manually shut down the reactors properly and all emergency equipment, including the diesel generators, ran as expected to keep the plant safe.
• In 1992, both reactors at the Turkey Point site in south Florida remained safe after Hurricane Andrew, one of the most powerful hurricanes to hit the United States, passed directly over the plant and knocked out the area’s electrical infrastructure. Turkey Point’s emergency diesel generators ran for six days.
Sources: POWERnews, NRC