UPDATE 1-NRC renews Exelon Pa. Three Mile Isl reactor license

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NEW YORK, Oct 22 (Reuters) - The U.S. Nuclear Regulatory Commission on Thursday renewed the operating license for Exelon Corp's 786-megawatt Unit 1 at the Three Mile Island nuclear plant in Pennsylvania for an additional 20 years until 2034.

The current license for Three Mile Island 1 expires April 19, 2014.

The sister unit at the plant near the Pennsylvania state capital of Harrisburg created worldwide headlines in 1979 when it partially melted down in the worst U.S. nuclear power accident.

The accident made Three Mile Island synonymous with the dangers of nuclear power and helped stop expansion of the U.S. nuclear industry until the recent slow-moving "nuclear renaissance."

Exelon, the biggest nuclear power operator in the United States, did not own Three Mile Island at the time of the accident.

Since 2000, when the NRC approved its first 20-year license renewal, the Commission has granted new licenses for 55 reactors, including Three Mile Island. The agency is now evaluating 13 applications for 20 units.

There are 104 reactors operating in the United States.