BERWICK (AP) — PPL Corp. will seek permission to build a third reactor at the atomic power plant it operates in northeastern Pennsylvania, the company announced Wednesday.

PPL has hired UniStar Nuclear Energy LLC, a joint venture of Constellation Energy Group Inc. and France’s EDF Group, to prepare the application to the U.S. Nuclear Regulatory Commission by the end of 2008.

PPL said it has not decided whether to move forward with construction.

“PPL would not undertake nuclear construction alone,” William H. Spence, PPL’s executive vice president and chief operating officer, said in a statement. “Because of the large capital commitment required, we would proceed with nuclear construction only as part of some type of joint venture.”

PPL is discussing possible joint ventures, but declined to release details.

The company said it does not expect the cost of the licensing effort to affect earnings from ongoing operations.

The two existing reactors at the Susquehanna plant were built in the 1980s at a cost of $2 billion each. Together, they are responsible for 25 percent of PPL’s annual output.

The 2,360-megawatt plant, just north of Berwick on the Susquehanna River, is owned jointly by PPL Susquehanna LLC and Allegheny Electric Cooperative Inc. It is operated by PPL Susquehanna.

Constellation Energy is based in Baltimore.