The long-anticipated start of a facility to treat sodium-bearing liquid radioactive and hazardous waste at the Energy Department’s Idaho National Laboratory recently took another step toward reality, Fluor Idaho said.
The contractor said Tuesday it finished a 50-day demonstration of the Integrated Waste Treatment Unit (IWTU). During the longest trial run to date the plant treated 62,200 gallons of a non-radioactive simulant that serves as a proxy for waste from underground tanks at INL.
Fluor said that test run which started in February, shows changes made to the primary reaction vessel, dubbed the denitration mineralization reformer, worked. The bottom of the vessel was changed from a spherical to a conical shape to better convert liquid waste to a granular solid.
Fluor Idaho will now go through a several-month outage to make final tweaks to prepare the plant for operations. The company also must complete a system performance test prior to starting routine radiological operations, according to the Idaho Department of Environmental Quality.
During a 30-day test during the summer of 2018, the facility turned more than 53,000 gallons of liquid simulant into a dry, granular solid, Fluor Idaho said.
Remaining operational modifications to the IWTU will be made during the current outage; the majority of modifications remaining were identified prior to the 50-day run and are to support radiological operations, Fluor spokesman Erik Simpson said Friday. “There is no set timeframe for the completion of such modifications.”
Designed to treat 900,000 gallons of sodium-bearing waste now stored in stainless steel tanks, construction of the IWTU was finished in 2012, but it failed to work as intended.
The facility is needed to comply with a 1995 settlement agreement between Idaho, the Energy Department, and the U.S. Navy over storage of nuclear waste at INL. The agreement said sodium bearing-waste at INL should be treated by 2012.
As of January, Idaho has hit DOE with more than $5.3 million in penalties for failure to begin operating the Integrated Waste Treatment Unit. The Energy Department is working off some of the fines by doing supplemental environmental projects for the state.
The state is processing a major permit modification to reflect the IWTU changes, DEQ Hazardous Waste Permit Supervisor Brian English said in a Tuesday email. “Unfortunately, there still remains an issue with corrosion in the process gas filter (PGF) that must be resolved. This likely will involve at least one more surrogate run,” as a result, he added.
Eventually, once Fluor and the Energy Department say the unit is ready to operate, DEQ will inspect the facility and observe the formal performance testing, English said.
