Press Release-I-10-004, NRC Sends Special Inspection Team to Calvert Cliffs

Press Release-I-10-004: NRC Sends Special Inspection Team to Calvert Cliffs

ML100550835
Person / Time
Site:	Calvert Cliffs
Issue date:	02/22/2010
From:	Office of Public Affairs Region I
To:
Category:Press Release
References
Press Release-I-10-004
Download: ML100550835 (1)

Text

NRC NEWS U.S. NUCLEAR REGULATORY COMMISSION Office of Public Affairs, Region I 475 Allendale Road, King of Prussia, Pa. 19406 Site: http://www.nrc.gov No. I-10-004 February 22, 2010

Contact:

Diane Screnci, 610/337-5330 E-mail: opa1@nrc.gov Neil Sheehan, 610/337-5331 NRC SENDS SPECIAL INSPECTION TEAM TO CALVERT CLIFFS The Nuclear Regulatory Commission has sent a team of inspectors to the Calvert Cliffs nuclear power plant to follow-up on the shutdown of both reactors last week. The two-unit plant, which is operated by Constellation Energy LLC, is located in Lusby, Md.

The five-member Special Inspection Team began its work today (2/22). The inspectors will focus their efforts on gaining a better understanding of what happened.

On Thursday, February 18, one of two electrical distribution buses for the site was lost at about 8:24 a.m. A bus is an electrical connection between multiple electrical devices. This loss of power caused Unit 2s reactor coolant pumps and reactor to automatically trip. One Unit 1 reactor coolant pump also tripped, resulting in a unit trip.

The loss of the electrical bus also caused a loss of power to some safety systems. Nuclear power plants are designed with backup power sources, typically emergency diesel generators, to provide power to essential safety systems. At Unit 1, one of the emergency diesel generators (EDG) started as expected and supplied power to the affected safety bus. The Unit 2 EDG initially started, but then tripped. Workers tied-in another power source to return power to the Unit 2 bus and its associated redundant safety equipment.

All other safety systems responded as designed. Both units are stable. Unit 1 began a pre-planned refueling outage on Friday, February 19.

There was no safety consequence to plant workers, the public, or the environment associated with the shutdowns, said NRC Regional Administrator Sam Collins. The NRC resident inspectors were in the plants control room to monitor the reactor operators response, he added. The team will review the causes of the shutdown and how the plant operators and equipment responded to it.

The team will document its findings and conclusions in a report to be issued within 45 days of end of the inspection.

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