Radioactive sludge barrel ruptures at Idaho nuclear site

Storage vessel was being prepared for shipment to Carlsbad

BOISE, Idaho — A barrel containing radioactive sludge ruptured at an 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 barrel ruptured late Wednesday at the 890-square-mile site that includes the Idaho National Laboratory, one of the nation’s top federal nuclear research labs.

Federal officials said it’s the first known rupture of a barrel containing radioactive sludge at the site but might not be the last.

That’s because secretive record-keeping during the Cold War makes it hard for officials to know the exact contents of similar barrels, said Idaho National Laboratory Joint Information Center spokesman Don Miley.

The barrel contains a mixture of fluids and solvents that came from the Rocky Flats Plant near Denver.

Officials during the Cold War were extremely secretive about the contents of the barrels for fear that the process of making nuclear weapons could be revealed if the contents were known, Miley said.

A preliminary theory about the cause of the rupture, he said, is that radioactive decay made the barrel heat up and ignite particles of uranium. An investigation is planned.

“They haven’t run into anything like this actually happening,” he said. “They’ve got a really good idea of what’s in (the barrels), but they might not always know the concentrations.”

He said an investigation will try to determine if there are other barrels at risk of rupturing.

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 barrels are in the ear then floor structure that’s 380 feet long and 165 feet wide. The barrel that ruptured had been moved to the containment structure in preparation for shipment to the Waste Isolation Pilot Plant near Carlsbad.

At the underground repository in 2014, a barrel of radioactive waste ruptured after being inappropriately packed at Los Alamos National Laboratory. The waste had been mixed with organic cat litter to absorb moisture, resulting in a chemical reaction.