Exelon Corp. on Tuesday named a new chief executive of Exelon Generation, its Kennett Square subsidiary that manages 35,000 megawatts of power plants, including the nations' largest fleet of nuclear reactors.

Kenneth W. Cornew, who was formerly president and chief executive of Exelon's Constellation business unit in Baltimore, will also assume the titles of senior executive vice president and chief commercial officer of the Exelon parent company.

Exelon Generation previously was overseen by Christopher M. Crane, who became Exelon's president and CEO last year after Exelon merged with Constellation.

Cornew's vacated position at Constellation's headquarters in Baltimore will be filled by Joseph Nigro, formerly Constellation's senior vice president of portfolio management and strategy.