SALEM TWP. -- PPL will be testing its warning sirens at the Susquehanna nuclear plant today at 11 a.m. The annual test helps "ensure the emergency warning system is working properly," said PPL spokesperson Joe Scopelliti. "The sirens are an important part of our emergency communication system to ask the public to tune into local news stations for information." The sirens will sound once for three minutes, followed by radio and television alerts carrying a message about the tests, according to Scopelliti.