 Mark Fouser, WDEL, Delaware's News Radio. Residents and parts of Delaware can expect to hear an emergency siren test tonight. DEMA testing the alert system for the Salem and Hope Creek nuclear power plants around 7.20 p.m. Those sirens will last three to five minutes, warning those within 10 miles of the reactors to listen to WDEL for an emergency alert message. The radius includes parts of Delaware City, Middletown, Odessa, and Townsend. The