Peach Bottom Atomic Power Station and Three Mile Island Nuclear Generating Station will test their new emergency sirens later this week.
At 1 p.m. Wednesday, all 97 emergency warning sirens will sound in the 10-mile radius around the Delta station.
The new sirens are part of parent company Exelon Generation's $11 million investment to replace 400 sirens throughout areas surrounding Peach Bottom, TMI and other nuclear power plants in the state.
In addition to notifying residents of a nuclear emergency, the sirens are also used by Pennsylvania and Maryland emergency management authorities to notify residents of severe weather.
Three Mile Island will test its new emergency sirens a day after Peach Bottom.
At 12:15 p.m. Thursday, all of its 96 warning sirens will sound for three minutes.
The tests are routinely conducted and are coordinated with Cumberland, Dauphin, Lancaster, Lebanon and York Counties and the Pennsylvania Emergency Management Agency.
With the installation of the new siren system, TMI and Peach Bottom are moving to a semi-annual testing schedule. The next test will be conducted during the first week of June, according to a company press release.