Aug 10 - McClatchy-Tribune Regional News - Rusty Dennen The Free Lance-Star, Fredericksburg, Va.



A faulty valve in a coolant system component resulted in a leak at North Anna Power Station, according to the Nuclear Regulatory Commission.

The leak Thursday was noted as an "unusual event" in an NRC report Friday.

Richard Zuercher, spokesman for Dominion power's nuclear operations, said yesterday that maintenance work on a valve caused the leak. The water was contained in a backup system.

The primary system allows the addition of chemicals to water that filters the reactor coolant system. Water drawn from Lake Anna is used to cool the station's two reactors.

 "The valve failed in a position directing the flow of water into another system that is designed to hold the leakage," Zuercher said.

Since the flow exceeded 75 gallons per minute, it was above the 25-gallon limit for the equipment, resulting in the incident being classified by the NRC as an unusual event.

Zuercher said all the water remained inside the piping system.

"Within six minutes, the valve was isolated and the leak was stopped."

He said the valve was repaired, tested and returned to service.

North Anna's Unit 1 reactor remained at full power during the event and local, state and federal agencies were notified.

Zuercher said there were no toxic releases or safety issues as a result of the valve failure.

The North Anna plant is located near Mineral in Louisa County. In Virginia, Dominion also owns and operates the Surry Power Station on the James River.

Rusty Dennen: 540/374-5431

Email: rdennen@freelancestar.com

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