NextEra planning to donate warning sirens to Linn County

Over 140 outdoor sirens no longer needed for nuclear warnings with Duane Arnold closure

CEDAR RAPIDS — An outdoor siren system installed decades ago to warn of a nuclear emergency at the Duane Arnold Energy Center in Palo now may be donated to Linn County for severe weather notification.

NextEra Energy Resources, owner of the now-retired nuclear power plant, has said it will donate 144 Whelen outdoor sirens and four control stations — together worth more than $1 million — to the Linn County Emergency Management Agency.

Before accepting the sirens, Linn County has to figure out how much it will cost to maintain them and make sure the county can afford it, said Steve O’Konek, Linn County’s emergency coordinator.

“The Linn County Emergency Management Commission has agreed to accept them pending the cost of the maintenance with a vendor being acceptable,” O’Konek said.

Officials are reviewing proposals from three vendors to take over monthly testing, annual maintenance, upgrades and servicing of the sirens. The request for proposals calls for a three-year service agreement. O’Konek will make a recommendation to the commission later this month.

“In the interim, NextEra Energy Duane Arnold continues to maintain the system in good working order to ensure the system is ready for use at the will of the county emergency management agencies,” NextEra said in a statement to The Gazette.

The Linn County Board of Supervisors already has approved an additional $111,200 for the emergency agency’s budget to pay for an employee, training and technology that previously had been covered by NextEra.

Siren history

Originally, the sirens were required in a 10-mile radius of the Duane Arnold plant, opened in 1974. The goal of establishing such an Emergency Planning Zone was to prepare to warn residents of a potential exposure to radioactive materials.

On Dec. 14, 1981, Iowa Electric Light and Power Company (now Alliant Energy), the original owner of the facility, sent a letter to the U.S. Nuclear Regulatory Commission. The utility said an updated siren system had been installed and would be fully operational by Feb. 1, 1982.

The system was “designed to alert 100 percent of the population within the 5 mile EPZ and over 95 percent of the population between the 5 and 10 mile EPZ within 15 minutes,” the letter states. The remaining population within the 10-mile zone would be alerted by car or aircraft, the letter states.

The 1982 upgrade came after an NRC official criticized Duane Arnold’s emergency warning system in an 1980 inspection, according to an April 24, 1980, article in The Gazette. The inspector said the company’s plan “contains the commitment to notify the public within 15 minutes, but not the ability.”

The 1979 meltdown of a nuclear reactor at Three Mile Island in Middletown, Pa., created community panic and increased distrust of the industry, the NRC reported. There were only small radioactive releases and no detectable health effects from the incident, but it spurred nationwide improvements in safety.

NextEra had been planning to shutter Duane Arnold in 2020 because of rising costs at the aging facility and Iowa’s changing energy landscape. But the Aug. 10, 2020, derecho damaged the plant’s cooling towers and owners decided not to restart operations.

Will anything change with the sirens?

Of the 144 sirens, 109 are in Linn County and 36 in Benton County. The plan is for Linn County to accept ownership of all, but make the Benton County ones available to that county, O’Konek said.

Some of the sirens could be moved to parts of the county that need more siren coverage, he said.

The sirens still will broadcast a verbal, computer-generated message as part of tests on the first Wednesday of each month. NextEra technicians are removing the nuclear warnings, which no longer are needed, O’Konek said. The tornado siren — a long steady wail — will remain unchanged.

Most of the sirens are solar powered so they can operate even if there’s a power outage. But some are on the power grid.

“As part of this project we will likely, over the course of years and approved funding, upgrade and maintain these sirens to ensure they don’t fall into disrepair,” O’Konek said, adding that regular maintenance is cheaper than replacement.

In recent years the siren system was upgraded so sirens may be sounded in quadrants instead of the entire Linn County. This way, the emergency management agency can target warnings to areas where severe weather is expected. The quadrant boundaries for the siren system are County Home Road dividing north and south and Highway 13 separating east and west.

Comments: (319) 339-3157; erin.jordan@thegazette.com