FirstEnergy works on Ohio Davis-Besse reactor

NEW YORK, June 26 (Reuters) - FirstEnergy Corp (FE.N) was repairing a piece of equipment in the transmission switchyard at the 879-megawatt Davis-Besse nuclear power plant in Ohio that exploded early Thursday, the company told the U.S. Nuclear Regulatory Commission in a report.

The circuit fault knocked out one of the plant's two offsite power sources, a spokesman for the company said Friday.

The plant's technical specifications give workers 72 hours to restore the offsite power source or shut the plant.

The spokesman said the company expects to make the repairs within the 72-hour limit.

Despite the event, which destroyed the transmission equipment, the unit continued to run at full power.

There was no release of radiation and no harm to workers or the public due to this event. The switchyard is in a non-nuclear part of the plant.

The Davis-Besse station, which entered service in 1977, is located in Oak Harbor in Ottawa County about 35 miles east of Toledo, Ohio.

One MW powers about 800 homes in Ohio.

FirstEnergy has told the NRC it plans to file for a 20-year extension of the original 40-year operating license for the plant in August 2010.

FirstEnergy's FirstEnergy Nuclear Operating Co subsidiary runs the station.

FirstEnergy, of Akron, Ohio, owns and operates nearly 14,000 MW of generating capacity, markets energy commodities, and transmits and distributes electricity to about 4.5 million customers in Ohio, Pennsylvania and New Jersey. (Reporting by Scott DiSavino; Editing by John Picinich)