BYRON, Ill. (CBS) — Exelon was working to restore operations at a nuclear reactor unit near Rockford, after a reactor went down Monday morning.
Exelon spokeswoman Krista Lopykinski said the problem started at 10:18 a.m. in reactor Unit No. 2 at The Exelon Byron Nuclear Generating Station, located in Ogle County, about 100 miles west of Chicago, near Rockford.
The supply of power from off-site (needed to maintain backup for safety systems) went down, forcing Exelon to take Unit No. 2 offline, according to Lopykinski.
She said the problem is officially described as an “unusual event.”
“This is the lowest of four emergency classifications that’s established by the U.S. Nuclear Regulatory Commission and the reason they did that is because we had loss of off-site power,” Lopykinski said. “Also, our Unit 2 came offline as well.”
LISTEN: WBBM Newsradio’s John Cody reports
Lopykinski said depressurization of Unit 2 has required Exelon to release steam containing tritium – a radioactive isotope – into the air. She said the amount of tritium released was minimal and well within federal limits.
There has not been any evacuation at the plant an no injuries have been reported, according to Lopykinski.
Engineers were working to resume power production from the unit as of Monday afternoon.
Neighbors saw a single plume of steam rising from one of the giant stacks. Word quickly spread that something was going on.
Byron resident Patricia Carter grabbed her potassium iodide pills when she thought there could be an emergency at the station.
“Well I kind of panicked. And the first thing I did was go get those pills they’d given us,” she told CBS 2’s Pamela Jones.
The Byron nuclear plant has had its share of problems in recent years, WBBM Newsradio’s Steve Grzanich reports.
In 2008, a similar incident occurred involving electrical transformers at the plant after outside power to one of the reactors was interrupted.
In 2007, workers using a wire brush to clean corroded steel pipes broke through a pipe, causing a leak. Both reactors had to be shut down for 12 days.
And the Nuclear Regulatory Commission announced last April it was investigating whether backup cooling pumps would be able to cool the reactors if the normal system wasn’t working. Exelon initially said the pumps would work but later concluded they wouldn’t.
In 2010, the company agreed to pay more than $1 million to settle lawsuits filed by the Illinois Attorney General for allowing tritium to leak outside three nuclear power plants, including Byron.