BOISE, Idaho — A barrel containing radioactive sludge ruptured at an eastern Idaho nuclear facility, federal officials said Thursday, resulting in no injuries and no risk to the public but possibly slowing progress in shipping waste out of the state.
The U.S. Department of Energy said the 55-gallon (208-liter) barrel ruptured late Wednesday at the 890-square-mile (2,305-square-kilometer) site that includes the Idaho National Laboratory, the nation's top federal nuclear research lab about 55 miles west of Idaho Falls.
Officials said the Idaho National Laboratory Fire Department responded to a fire alarm at a containment structure at the Idaho Cleanup Project's Radioactive Waste Management Complex.
The barrel contains a mixture of fluids and solvents that came from nuclear weapons production at the Rocky Flats Plant near Denver, Colorado, said Idaho National Laboratory Joint Information Center spokesman Don Miley.
An early theory about the cause is that radioactive decay caused the barrel to heat up and ignite particles of uranium, he said, but an investigation is planned.
"That's going to be part of the recovery effort now," Miley said. "Finding out what happened."
Workers entering the structure, even before the breach, must use self-contained breathing apparatus and wear full protective clothing. Officials said no radiation has been detected outside the structure, which has special filters to prevent radioactive particles from escaping.
It's not clear how many similar barrels are in the earthen-floor structure that's 380 feet (116 meters) long and 165 feet (50 meters) wide. The barrel that ruptured had been moved to the containment structure in preparation for shipment to the Waste Isolation Pilot Plant near Carlsbad, New Mexico.
The sprawling Idaho site in high-desert sagebrush steppe sits atop the giant Eastern Snake Plain Aquifer that's used by cities for drinking water and farmers for irrigation. The area is near the striking 7,550-foot (2,300-meter) Big Southern Butte, which has a road to the top for adventurous drivers.
The federal site has been used for nuclear waste disposal and storage beginning in the 1950s. The federal government has been cleaning it up following court battles and several agreements with Idaho in the 1990s amid concerns by state officials that Idaho was becoming the nation's nuclear waste dump.
The Energy Department has already missed several deadlines under those agreements involving moving nuclear waste out of Idaho and has paid about $3.5 million in fines.
Idaho is also preventing research quantities of spent nuclear fuel from entering the state to be analyzed by Idaho National Laboratory scientists due to a missed deadline.
The federal agency also faces deadlines concerning waste stored in barrels, and the radioactive release and investigation could slow the process of moving that waste out of state.
The Energy Department has floated the idea of bringing in more nuclear waste from Hanford in Washington state for treatment at a $500 million facility at the Idaho site.
Idaho Attorney General Lawrence Wasden on Thursday declined to comment on the situation.
Wendy Wilson of the Snake River Alliance, an Idaho-based nuclear watchdog group, said the incident is a reminder of why the state should not allow more nuclear waste to be shipped into Idaho for treatment.
"It sure demonstrates how much things can go wrong when you're dealing with waste that hasn't been fully assessed," she said.