Three Mile Island Returns to Service

Exelon Nuclear

FOR IMMEDIATE RELEASE

LONDONDERRY TWP. (Sept. 21, 2010) – Three Mile Island Unit 1 returned to service yesterday at 10:50 p.m. when operators connected the plant’s turbine generator to the regional power grid. The turbine generator shut down on September 19 due to a faulty electrical card on a plant system. Plant personnel replaced the faulty electrical card.

Three Mile Island Unit 1 generates 852 megawatts of carbon free power - enough electricity for about 800,000 homes. Electric customers were not affected by the plant being off line.