After initial runs using a mix of radiological waste and nonradioactive simulant, the Integrated Waste Treatment Unit (IWTU) at the Idaho National Laboratory site has progressed to treating sodium-bearing waste entirely, the Department of Energy’s Office of Environmental Management (DOE-EM) announced on May 22.

Since the launch of operations just over a month ago, the Integrated Waste Treatment Unit (IWTU) at Idaho National Laboratory has increased sodium-bearing waste treatment fivefold. This activity is a vital step in removing the remaining liquid waste from nearby underground tanks at the site and protecting the underlying Snake River Plain Aquifer.

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 that heat-up of Idaho’s Integrated Waste Treatment Unit (IWTU) resumed in January. Crews began heating the IWTU in December in preparation of radiological operations, but the facility was shut down 10 days later after operators noticed a small leak of nonradioactive material inside one of the unit’s processing cells.

Located at the DOE’s Idaho National Laboratory Site, the IWTU is intended to treat Idaho’s 900,000 gallons of sodium-bearing liquid waste, converting it to a solid using a steam-reforming process.

After repairs were made to the IWTU equipment responsible for the leak, crews removed a partial obstruction that was in a line into the carbon reduction reformer, a key treatment vessel in the steam-reforming process, EM said.

Ten days after beginning a heat-up process to prepare for radiological operations at Idaho’s Integrated Waste Treatment Unit (IWTU), operators noticed a small leak of nonradioactive, nonhazardous solids in a cell, resulting in the facility’s shutdown in late December, the Department of Energy announced on January 10.

The Department of Energy’s Office of Environmental Management (EM) said that the Integrated Waste Treatment Unit (IWTU), the radioactive liquid waste treatment facility at the Idaho National Laboratory Site, began its final heat-up in December prior to initiating radiological operations, planned for early this year.

IWTU crews were to follow a prescribed incremental process as the facility transitions from simulant to sodium-bearing waste (SBW), according to EM.

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 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.