Sandy Leaves Behind Ongoing Alert at Oyster Creek, Three Tripped Reactors at Other Nuclear Plants

The 24 hours following Sandy's landfall brought widespread blackouts and conditions that resulted in shutdowns at three reactors, as well as the continuation of an alert at Oyster Creek.

Of 34 reactors in the regions reached by the storm, the Nuclear Energy Institute noted that 24 continued to generate power throughout the event, while a further seven were in scheduled outages. The reactors most affected by the storm remained in safe condition Tuesday.

Hurricane Sandy. Source: NOAAOyster Creek

An alert declared Monday night at Exelon's New Jersey nuclear plant continued into the following day as the water level slowly receded from the plant's intake structure. The unit had been shut down for service before the storm. According to an event report filed with the Nuclear Regulatory Commission, "The site also experienced a loss of offsite power event concurrent with the additional water level increase. Both emergency diesel generators started and are supplying power to the emergency electrical busses."

An update just after 4 a.m., Tuesday, added that, "This event caused a valid [reactor protection system] actuation with automatic containment isolations that resulted in a temporary loss of shut-down cooling to the reactor. Shutdown cooling was subsequently restored with power provided by the emergency diesel generators."

An Exelon spokesman told the New York Times Tuesday that no water had flooded into the plant.

Indian Point

Unit 3 shut down automatically from full power a 10:41 p.m., Monday, after a turbine trip, according to an NRC event report. In a release, Entergy said the trip was caused by a grid disturbance, and no damage resulted at the plant. Unit 2 continued to operate at full power.

Nine Mile Point

Unit 1 tripped at about 9 p.m., which Constellation Energy suspected was caused by generator load reject. The high pressure coolant injection system initiated automatically. It and other safety systems functioned as designed, according to an NRC event report, and three electromatic relief valves actuated and reclosed because of the scram.

Unit 2 continued to operate at full power after losing one of its 115kv power lines. According to an NRC event report, it went down "due to a lightening arrestor falling onto electrical components in the Scriba switchyard during high winds."

One emergency diesel generator provided backup power before the line was restored, about six hours later at 3:26 a.m., Tuesday, according to the report.

Salem

Operators manually shut down unit 1 from full power after the loss of four condenser circulators affected by high water levels and debris. According to an NRC event report, "A subsequent loss of the 2 remaining circulators required transition of decay heat removal from condenser steam dumps to the 11-14 MS10s (atmospheric steam dump). Decay heat removal is from the 11/12 Aux Feed Pumps to all 4 steam generators via the 11-14 MS10s ... All safety related equipment functioned as expected."

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  • UPDATE:

    Exelon ended the alert at Oyster Creek at about 4 a.m. this morning. The plant reported to the NRC that water levels at the intake have fallen below the unusual event threshold and continue to fall.

    Peter

    Nuclear Street News Team