Duke Energy: Error led to sirens wailing near Wake County nuclear power plant

Six sirens sounded by accident Monday morning near Duke Energy’s Shearon Harris Nuclear Plant.

The alerts rang while Duke was conducting “routine silent testing,” said company spokeswoman Anne McGovern. During that testing, the sound of six sirens were turned on, making them audible.

The noise started shortly before 8 a.m. in part of the 10-mile emergency planning area around the Harris plant, according to a joint release from Chatham and Wake county officials.

There are 85 sirens located within 10 miles of the southwestern Wake County plant Those that sounded were in Chatham and Wake counties, but McGovern said she could not provide specifics about their locations.

“The most important thing is that it was inadvertent so there was no emergency and that everything is operating safely at the plant,” McGovern said.

The alerts sounded while Duke was conducting “routine silent testing,” McGovern later said in an email. During that testing, the sound on a small number of sirens was turned on, making them audible.

“The sirens performed as designed,” McGovern wrote.

Triangle residents farther away than 10 miles received emergency alerts Monday announcing the activation and stressing that there was no “protective action” needed from the public.

In a social media post, Wake County said its officials are working with Duke Energy to figure out why the alarms sounded. As of 11:45 a.m., Duke officials had not identified the cause, McGovern said.

Responding to plant sirens

The sound of sirens around a nuclear power plant are a signal that people should tune into local radio or television to find out additional information and instructions, according to Duke. Stations would broadcast specific directions about what people nearby the plant should do.

A quarterly test of the emergency alert sirens is scheduled at the plant this week, but it is supposed to happen Wednesday. That test will go forward as planned, McGovern said.

Duke typically tests sirens around Shearon Harris between 10 a.m. and 11 a.m., with the alarms sounding between five and 30 seconds.

Emergency alert that went out to many Wake County residents Monday morning.
Emergency alert that went out to many Wake County residents Monday morning.

“Our inspectors at Shearon Harris will review the incident to ensure the company identifies the cause, understands why it happened, and takes steps to prevent a recurrence. Such incidents, while uncommon, can happen due to technical malfunctions or human error,” Gasperson wrote.

After the sirens sounded, residents scrambled for information on social media before any official clarification could be delivered:

A sample:

“People’s power flicker then we get alert for the Harris Nuclear Plant down the road but…..” Brandon, a UNC grad student, posted on X.

“30-60 minutes late for these messages is way too late,” posted Adam Sullivan on Facebook.

Emergency sirens from the Harris plant were also accidentally activated in 2018. A spokesman for Duke Energy said at the time that there were 83 sirens within 10 miles of the plant, and that several had misfired in both Cary and Apex.

That incident triggered many questions about why it took state officials 38 minutes to correct the message.

The plant’s emergency planning area in 2024 includes eastern Chatham County, northeastern Lee County and fast-growing western Wake County towns Apex, Holly Springs and Fuquay-Varina.

The plant has operated since 1987 and is located in New Hill, which is about 25 miles southwest of Raleigh.

This story was produced with financial support from the Hartfield Foundation and Green South Foundation, in partnership with Journalism Funding Partners, as part of an independent journalism fellowship program. The N&O maintains full editorial control of the work. If you would like to help support local journalism, please consider signing up for a digital subscription, which you can do here.