The Department of Energy has produced its first 18 canisters of solidified granular waste with the Integrated Waste Treatment Unit (IWTU) at the Idaho National Laboratory, agency officials told a federal advisory panel Thursday.
The $1.4-billion Integrated Waste Treatment Unit (IWTU) began radiological operations April 11, Mark Brown, deputy manager of DOE’s Idaho nuclear, told the local Citizens Advisory Board.
The filled canisters go into concrete vaults that each hold 16 canisters, Brown said. Waste treatment is starting out slowly, “while we figure some things out.”
DOE’s Jacobs-led contractor, Idaho Environmental Coalition will continue processing a blend of 90% simulant and 10% sodium-bearing waste for four weeks, he said.
The IWTU will then operate with a 50/50 mixture for two weeks before finally shifting to 100% sodium-bearing high-level waste, Brown said.
“As you can imagine in any nuclear facility startup, we are having adjustments that we have to make to the facility and try and figure out how the plant is actually going to work the best,” Brown said.
The long-delayed IWTU, designed to convert about 900,000 gallons of sodium-bearing liquid waste from the Idaho Nuclear Technical and Engineering Center into sand-like granular waste, factors into future nuclear research at the national laboratory, said Connie Flohr, DOE’s manager for the Idaho cleanup project.
Under a federal-state legal settlement updated in 2019, DOE’s authority to import limited amounts of spent fuel to the Idaho National Laboratory is tied to the production of solidified waste cans from IWTU, Flohr said.
“The first can allows us to bring in the first small quantity of research spent fuel into the state” with more allowed after “100 cans,” Brown said.
If the IWTU operates as planned, all the liquid waste should be converted into a granular form within five years or so, Flohr said.
Should DOE’s Waste Isolation Pilot Plant near Carlsbad, N.M., ever get a permit modification to allow disposal of tank waste, it is conceivable solidified waste from the IWTU could eventually go into the underground salt mine as remote-handled transuranic waste, Flohr said.
For the short-term, however, DOE and its environmental contractor continue to work the kinks out of the IWTU, Brown said. This includes doing certain system performance tests and converting the on-site nitrogen generation system for IWTU to electric power from diesel.
The Citizens Advisory Board meeting, which originated from Idaho Falls, was also carried via Zoom.
A contractor team led by CH2M, now owned by Jacobs, started building the steam reforming plant in 2007. Although construction was finished in 2012, the IWTU didn’t work as intended until this year.
From 2012 to 2023, the project underwent a major overhaul. Testing with non-radioactive simulated waste, or simulant, began under contractor Fluor Idaho and then, starting in early 2022, the Jacobs-led Idaho Environmental Coalition.
