Caption: Calvert Cliffs nuclear power plant
The U.S. Nuclear Regulatory Commission (NRC) started a special inspection at the Calvert Cliffs nuclear power plant in Maryland following the shutdown of both units.
A grid disturbance due to the failure of a transmission line on April 7 caused both units to automatically shut down as designed and led to widespread blackouts in Washington DC. Following the disturbance, one of Unit 2’s emergency diesel generators started, but tripped after 11 seconds. In addition, one of three saltwater pumps on Unit 2 failed to automatically restart when power switched to the emergency diesel generators. Per procedure, operators manually started the pump, which provides cooling water to certain plant equipment.
The three-member inspection team that arrived on-site is tasked with developing a sequence of events; reviewing and assessing equipment response to the event; reviewing operator performance; and assessing the effectiveness of Exelon (NYSE: EXC)’s response to the problem. An inspection report documenting the team’s findings will be issued within 45 days of the end of the inspection.
Subscribe to Nuclear Power International magazine