OAK RIDGE, Tenn. — Chips of uranium metal sparked at Y-12 on Feb. 22, 2023, causing the emergency response, said Y-12 Communications manager Taz Painter in an email to 10News.
"The event involved rapid exothermic oxidation, a known hazard for which we have established plans," Painter said in the email.
A Tennessee Emergency Management Agency situation report, obtained through an open records request, said crews tried to put out the fire using petroleum coke, but "the fire continued," the report said.
"The time to extinguish the reaction was longer than expected, so an emergency was declared as a precaution," Painter said.
Painter said Building 9212, where the fire happened, was evacuated and firefighters "applied additional coke and allowed the oxidation to complete under the coke container."
He said the fire was contained to a hood, and the fire was under one square foot.
On Feb. 22, Y-12 tweeted about a fire "under a hood," which started around 9:15 a.m.
The TEMA situation report said at 9:44 a.m., Y-12 declared a site area emergency, which ended at 6:28 p.m. that day.
"This is a very serious incident," said Dr. Marco Kaltofen, a forensic nuclear scientist. "It is, in fact, the worst kind of failure that you might be trying to ward off in a facility like this."
Painter said Y-12 knows the hazards of working with uranium and has "established plans to mitigate those hazards" in place.
"Our highest priority is to protect our workers, the public, and the environment," Painter said.
In 2022, Y-12 studied the hazards associated with the metals used at the national security complex.
In the Reactive Materials Hazard Review, the Defense Nuclear Facilities Safety Board staff said enriched uranium chips form from machining operations. Those chips are processed to "form briquettes for interim storage," the report said.