Exelon's Three Mile Island seeks license extension

HOUSTON, Jan 8 (Reuters) - A unit of Exelon Corp (EXC.N) has filed an application with federal nuclear regulators to extend the operating license of Three Mile Island Unit 1 nuclear generating station by 20 years, the company said on Tuesday.

The current license for the 786-megawatt reactor in Lononderry Township, Pennsylvania, about 10 miles southeast of Harrisburg, expires in April 2014.

If approved by the U.S. Nuclear Regulatory Commission, Three Mile Island could operate until April 2034, said AmerGen Energy Co, a subsidiary of Chicago-based Exelon, the largest operator of nuclear plants in the U.S.

Since buying the station in 1999, AmerGen has invested more than $100 million to upgrade equipment and facilities at the station, the company said. AmerGen will invest another $300 million during a 2009 refueling outage to replace two steam generators.

Three Mile Island began commercial operation in 1974. Unit 1 has set four world records for continuous days of operation for a pressurized water reactor, one of two primary U.S. reactor designs, the company said.

Unit 2 was shut after a severe core meltdown accident in 1979. Although the most serious accident in U.S. nuclear industry history, there were no deaths or injuries at the plant or in the community, according to the NRC.

The agency is expected to spend 22 to 30 months to review the application.

The NRC has approved license renewals for 48 generating stations and 38 other license renewal applications are pending or are expected to be filed in the next few years.

Regulators approved extensions for Exelon's Peach Bottom Generating Station in York County, Pennsylvania, in 2003 and the Dresden and Quad Cities Generating Stations in Illinois in 2004.

The NRC is reviewing a renewal application for Oyster Creek Generating Station in New Jersey.

A coalition of environmental groups is working to suspend all pending relicensing efforts by the NRC, citing problems with the agency's process. (Reporting by Eileen O'Grady)