IDAHO FALLS, Idaho – Sixteen years after EM broke ground for the Integrated Waste Treatment Unit (IWTU), the first-of-a-kind facility began treating radioactive liquid waste from underground tanks at the Idaho National Laboratory (INL) Site on the afternoon of Tuesday, April 11.

It was a bittersweet moment for the operators, engineers and other staff members, some of whom have been with the project since its inception.

At 2:30 p.m., the IWTU began treating a blend that was 10% sodium-bearing waste and 90% non-radioactive simulated waste, or simulant. Operators filled the first canister of treated waste at 4:35 a.m. the following morning. During the night, feed nozzles clogged intermittently — an anticipated challenge — but have since been cleared according to operating procedures.

IWTU was constructed between 2007 and 2011 to convert 900,000 gallons of radioactive liquid waste from the tanks at the Idaho Nuclear Technology and Engineering Center (INTEC) to a granular solid resembling coarse sand using steam-reforming technology. The IWTU facility underwent testing, modifications and several simulant test runs in subsequent years in the run-up to radiological operations.

Staff supporting the project remained committed to the mission regardless of the plant’s past technical challenges, which have since been resolved.

“The level of dedication of this staff at both IWTU and INTEC is among the best I’ve witnessed in my 35-plus years in the nuclear industry,” said Bill Kirby, Idaho Environmental Coalition senior director of liquid waste and fuels. “I want to personally thank everyone associated with this project for getting us to this critical point of radiological operations. There will be challenges to come, but I’m confident we have some of the best qualified nuclear facility staff in the DOE complex to resolve those challenges.”

IWTU Nuclear Startup and Operations Director Jimmy Spells, who has been with the project almost exclusively since 2011, was equally appreciative of his team members.

“I was so happy for our employees when we started treating sodium-bearing waste,” he said. “This was the reward that many people deserved for their years of dedicated service to this facility.”

Integrated Waste Treatment Unit project engineer Allyson Ferry is pictured in the control room of the treatment facility at the Idaho National Laboratory Site.
Integrated Waste Treatment Unit project engineer Allyson Ferry is pictured in the control room of the treatment facility at the Idaho National Laboratory Site.

Engineer Allyson Ferry, who joined IWTU staff shortly out of college in 2017, said the startup at first was a little stressful but also rewarding.

“It was really exciting,” she said. “It was nerve-wracking for a bit because everyone was holding their breath, but when we saw it was working, there was a collective sigh of relief and then it was like a normal day.”

Ferry’s first role at the IWTU was to improve the fluidization of billions of tiny beads in the facility’s primary reaction vessel. She helped develop a new system that better fluidizes the beads, which are necessary to convert a liquid waste into a solid under the right temperatures and pressure.

Later, Ferry served on a team to resolve challenges with the process gas filter, which removes fine solids from gases generated in the primary reaction vessel.

“It was a full-circle moment,” she said while monitoring the processes she helped to fix. “It was really rewarding. To see the hard work pay off was a neat experience.”