NRC MONITORING UNUSUAL EVENT AT MILLSTONE 2 NUCLEAR PLANT
Printable Version

The Nuclear Regulatory Commission (NRC) is monitoring an Unusual Event declared this morning at the Millstone 2 nuclear power plant in Waterford, Conn. An Unusual Event is the lowest of four levels of emergency classification used by the NRC.

At 9:38 a.m. today, Millstone 2 lost off-site power for reasons that are still being investigated. (Nuclear power plants, besides sending electricity to the grid, also use a small percentage of their electrical output to power certain operational equipment.) In response, plant owner and operator Dominion declared an Unusual Event at 9:54 a.m. due to a loss of off-site power for greater than 15 minutes. 

As designed, the pressurized-water reactor shut down and the plant’s two emergency diesel generators, which provide back-up power when off-site power is lost, started to provide electricity to key safety systems. One of two required off-site power sources has been restored to the plant’s electrical distribution system. That occurred at approximately 11:06 a.m.

Millstone 2 was in the process of being restarted and was at a low power level at the time of the event. The unit had been shut down on May 22 in response to a turbine trip, or shutdown, believed to be caused by a lightning strike at a substation located about 2 ½ miles from the plant. Dominion continues to evaluate the root cause of the May 22 shutdown and whether there is any connection between the electrical problem that caused that event and the loss of off-site power earlier today.

The NRC began formally monitoring the event at 10:24 a.m. today. A Resident Inspector assigned to the plant was already on-site at the time of the event to monitor the plant start-up from the May 22nd shutdown and immediately began monitoring the company’s actions in response to the shutdown. In addition, the Incident Response Center at the NRC’s Region I Office in King of Prussia, Pa., was activated to track developments at the plant, maintain close communications, and determine if any additional actions were needed.

Millstone 3, an adjoining pressurized-water reactor owned and operated by Dominion, was not affected by the event and continues to operate at 100-percent power.

Federal and state officials have been notified regarding the event.

NRC news releases are available through a free listserv subscription at the following Web address: http://www.nrc.gov/public-involve/listserver.html. The NRC Home Page at www.nrc.gov also offers a Subscribe to News link in the News & Information menu. E-mail notifications are sent to subscribers when news releases are posted to NRC's Web Site.

Privacy Policy | Site Disclaimer
Wednesday, May 28, 2008