Dominion was forced to shut down Millstone Unit 2 over the July 26 weekend because of the failure of feedwater pump circulation, according to information the company provided to the NRC.
Unit 2 remained shut on Monday, July 28, 2014.
The failure of the turbine-driven auxiliary feedwater pump circulation forced a controlled shutdown from full power to a “hot standby” condition within 6 hours of the pump failure and “hot shutdown” condition within an additional 12 hours, according to Dominion.
Dominion reported to the NRC that its normal procedures including troubleshooting and repairs “were unable to determine and correct cause of low pump recirculation flows.”
Two months ago, on May 25, both Millstone Units 2 and 3 suffered emergency shutdowns simultaneously. Dominion attributed the scrams – classified as the lowest of 4 emergency levels – to a loss of offsite power.
Here is the NRC posting on the Unit 2 shutdown:
Posted July 28, 2014