Exciter Vibration Shuts Down North Anna Reactor

Operators bringing North Anna unit 2 out of a refueling outage shut down the reactor again after reports of vibration and arcing in the main turbine.

North Anna nuclear plant. Source: NRCThe Westinghouse reactor was at 60 percent power Friday when workers reported increased vibration and arcing on a bearing of the main generator exciter, according to a report filed with the Nuclear Regulatory Commission. The manual trip actuated auxiliary feedwater pumps automatically, and decay heat was removed using condenser steam dumps, according to the NRC.

A Dominion spokesman told the Richmond Times-Dispatch that about 20 people were troubleshooting the generator, including Siemens technicians and workers on site for the earlier refueling outage that began April 7. The unit remained offline Monday, and Dominion would not estimate when it would return to service.

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