Nuclear Plants Bringing Power Back After Irene

Two reactors were shut because of the storm, including one plant damaged by wind-driven debris. The two reactors remained offline today as safety reviews were conducted.

Constellation Energy Group Inc.’s Unit 1 at its Calvert Cliffs plant in Maryland shut down automatically when a piece of aluminum siding, ripped from a nearby building by Irene’s winds, crashed into a transformer, causing an explosion. The unit “remains in safe shutdown,” Constellation said in a statement.

“We will not bring the unit back online until all required precautionary testing has been completed,” the company said. A second Calvert Cliffs reactor remains at full power.

Exelon Corp. began restarting its Oyster Creek plant in New Jersey after shutting the reactor in advance of the storm. The restart process “takes some time,” Suzanne D’Ambrosio, a plant spokeswoman, said in an e-mail today. The reactor was listed at 1 percent of full power in a report from the U.S. Nuclear Regulatory Commission today.

Plants on the U.S. East Coast hit by the storm “responded appropriately” to Irene-related events, Scott Burnell, a spokesman for the NRC, said in an interview today. He said the plants didn’t encounter any emergency conditions that required warning the public.

The problems the nuclear plants did encounter underscore the need for upgrading safety systems at U.S. facilities to protect against extreme weather such as hurricanes and this month’s earthquake in Virginia, U.S. Representative Edward Markey said in a letter to the NRC today.

The Massachusetts Democrat cited “challenges” at nuclear plants during the hurricane, such as Calvert Cliffs’ shutdown and a backup generator at the plant that was disabled because of flooding. The congressman said some plants’ emergency sirens lost function or were on backup battery power during the storm.

Mark Sullivan, a spokesman for Baltimore-based Constellation’s nuclear venture, said in an e-mail that the diesel generator wasn’t needed at Calvert Cliffs because the site didn’t lose power, and that the plant has multiple diesel generators available.

“Operators in the control room followed procedures and managed the event as trained,” Sullivan said.

Markey also said the cooling pool used to store nuclear waste at the Millstone plant’s inactive reactor in Connecticut lost power for its cooling system during the storm. At one of the active reactors at Dominion Resources Inc.’s Millstone station, one of six water circulation pumps used for cooling also failed.

The pump was restarted within about a half-hour, Ken Holt, a plant spokesman, said in an interview today. He said the company was preparing to cool the Unit 1 fuel waste with a backup generator, though power returned before that was necessary.

“Neither one of these issues compromised public safety,” Holt said.

Dominion reduced power by about half at both its operating reactors at Millstone before the storm. The company is working to bring the reactors back to full operating capacity, Holt said.

Progress Energy Inc. expected to have both reactors at its North Carolina Brunswick plant restored to full power by the end of the day, Ryan Mosier, a plant spokesman, said in an interview. The plant suffered no damage in the storm, he said.

“The infrastructure out there in the grid is a lot more susceptible to storm damage than the plant systems themselves,” Mosier said.