IWTU operators prepare to introduce radiological sodium-bearing liquid waste into the facility Tuesday. (Photo: DOE)

More than a decade after construction was declared completed, Idaho’s long-delayed Integrated Waste Treatment Unit (IWTU) has begun radiological operations, the Department of Energy’s Office of Environmental Management (EM) announced.

On Tuesday, crews at the Idaho National Laboratory Site began sending radioactive sodium-bearing liquid waste from nearby underground tanks to the IWTU for treatment. The 900,000 gallons of waste was generated during decontamination activities following spent nuclear fuel reprocessing that ended in 1992.

The IWTU uses steam reforming fluidized-bed reactor technology to convert liquid waste to a granular solid resembling coarse sand more suitable for long-term disposal.

The Department of Energy’s Office of Environmental Management (EM) said it continues to make progress toward the start of operations of the Idaho National Laboratory Site’s Integrated Waste Treatment Unit (IWTU), having completed a final test run of the facility.

Operation of the IWTU, which was constructed to treat approximately 900,000 gallons of radioactive liquid waste, has been delayed a number of times, most recently due to supply chain issues.

The last spent nuclear fuel elements from Idaho National Laboratory’s Advanced Test Reactor (ATR) have been retrieved from a water-filled storage basin and transferred to a nearby dry-storage facility in accordance with a 1995 agreement with the State of Idaho, the Department of Energy’s Office of Environmental Management (EM) announced this week.

The Department of Energy’s Office of Environmental Management (EM) stated on February 22 that its Idaho National Laboratory Site contractor is operating the final test run of the Integrated Waste Treatment Unit (IWTU), running waste simulant through the facility to ensure the plant’s performance and personnel proficiency for upcoming radiological operations.