NRC Maintains Heightened Watch Over Nuclear Plants Impacted by Hurricane Sandy
The U.S. Nuclear Regulatory Commission continues to maintain its heightened watch over nuclear power plants in the Northeastern United States impacted by Sandy. Three reactors experienced shutdowns during the storm while another plant, Oyster Creek in New Jersey, remains in an “Alert” due to high water levels in its water intake structure.
The three reactors to experience trips, or shutdowns, during the storm are Nine Mile Point 1 in Scriba, N.Y., Indian Point 3 in Buchanan, N.Y.; and Salem Unit 1 in Hancocks Bridge, N.J.
Nine Mile Point 1 underwent an automatic shutdown at about 9 p.m. Monday when an electrical fault occurred on power lines used to send power to the grid. It is likely a storm-related event, but the plant’s operators are still evaluating the cause. All plant safety systems responded as designed and the shutdown was safely carried out. Meanwhile, Nine Mile Point 2 experienced a loss of one of two incoming off-site power lines as a result of the fault. One of the plant’s emergency diesel generators started in response to generate power usually provided by the line. Nine Mile Point 2 remained at full power.
Indian Point 3 automatically shut down at about 10:40 p.m. Monday in response to electrical grid disturbances caused by the storm. All safety systems responded as designed and the unit was placed in a safe shutdown condition.
Salem Unit 1 was manually shut down by plant operators at about 1:10 a.m. Tuesday as a result of circulating-water pumps being affected by high river level and debris in the waterway. The circulating-water system is used to cool down steam generated by the reactor; it is a closed system that does not come into contact with any radioactivity.
At Oyster Creek, the Alert was declared at approximately 8:45 p.m. An alert is the second-lowest level of emergency classification used by the NRC. The Alert was preceded by an “Unusual Event” at about 7 p.m. when the water level first reached a minimum high water level criteria. The water level rose due to a combination of a rising tide, wind direction and storm surge. While the water level has dropped since peaking earlier today, the Alert will not be exited
until the level is below the specific criteria for the intake structure, which is where water from an intake canal is pumped into the plant for cooling purposes. Oyster Creek was shut down for a refueling and maintenance outage prior to the storm and the reactor remains out of service.
The NRC will continue to coordinate with other federal and state agencies prior to the restart of the affected plants.
The NRC stationed inspectors at all of the plants expected to experience the greatest effects of the storm. Those inspectors were tasked with independently verifying that operators were following relevant procedures to ensure plant safety before, during and after the storm.
In addition, the NRC has been monitoring the storm from its emergency response centers.
Nuclear power plant procedures require that the facilities shut down under certain severe weather conditions. The plants’ emergency diesel generators are available if off-site power is lost during the storm. Also, all plants have flood protection above the predicted storm surge, and key components and systems are housed in watertight buildings capable of withstanding hurricane-force winds and flooding.
For more information, visit www.nrc.gov.