It's going to be a noisy lunch hour Wednesday near the Palo Verde Nuclear Generating Station about 50 miles west of Phoenix.
Sirens designed to alert residents who live nearby about radiation emergencies will be tested twice.
The 48 warning sirens in a 10-mile radius around the plant will be sounded for three minutes at noon and again 30 minutes later, officials said.
One of three emergency response agencies (Maricopa County Emergency Management Department, Maricopa County Sheriff's Office or Arizona Department of Public Safety) would activate the sirens if a nuclear emergency happened at the triple-reactor plant in Wintersburg.
The Arizona Department of Transportation will use electronic message signs to notify drivers on Interstate 10 of Wednesday's test.
The siren tests are done once a year and are part of the "Alert and Notification System" required by federal regulations. Area residents are provided materials on how to respond in an emergency.
Copyright 2013 CBS 5 (KPHO Broadcasting Corporation). All rights reserved. The Associated Press contributed to this report.