The Idaho Department of Environmental Quality is considering a permit modification sought by a U.S. Energy Department contractor preparing to start repackaging radioactive waste at a new location within the Idaho National Laboratory following an April 2018 accident.
The waste was generated decades ago at the Rocky Flats nuclear weapons plant in Colorado and was subsequently buried, in the original drums, at Idaho National Laboratory. Lab cleanup contractor Fluor Idaho has been repackaging the material since 2005 for eventual disposal at the Waste Isolation Pilot Plant in New Mexico.
The repackaging is intended to sort out potential sources of ignition and also place the legacy waste into newer containers for transport.
The company wants to relocate repackaging from the site of the incident to a different facility at one of the nine Accelerated Retrieval Projects within the 177-acre Radioactive Waste Management Complex – specifically, Waste Management Facility (WMF) 1619.
Fluor Idaho filed the permit modification Sept. 21 to move its sludge repackaging from Waste Management Facility 1617, where four drums of radioactive waste overheated and blew off their lids. The vendor finished repackaging the waste left over from the 2018 accident in August at that facility.
The company is seeking revisions to the state permit issued under the Hazardous Waste Management Act (HWMA) and the Resource Conservation and Recovery Act (RCRA). The permit incorporates the increased raking, thermal monitoring, and measures to ensure incompatible chemicals don’t end up in the same drum as repackaging proceeds.
The permit revision requires Fluor to complete certain upgrades and certify the building is ready for HWMA/RCRA operations before processing can begin, Brian English, Idaho DEQ hazardous waste permit supervisor, said in a Wednesday email. The state agency expects to make a ruling within 90 days of the date the Sept. 21 modification request – leaving 60 days for public comment and 30 days for decision making.
The new location is similar in design and construction to WMF-1617: a fabric building operated at negative pressure for radiological operations, English said. Fluor Idaho is in the process of relocating equipment from WMF-1617 to WMF-1619 for continued use. The company is also drafting a closure plan for the old site.
Fluor Idaho has implemented new safety precautions in the wake of the 2018 accident. The changes include additional raking with equipment to smooth out the material after it is removed from the original drums, along with holding the material inside waste trays in the retrieval area for 24 hours prior to repackaging. This should identify potential overheating or sparking after the waste contacts air and before it goes into a new drum.
The accident resulted from “slow oxidation” of uranium metal that combined with flammable methane gas inside the drums hours after being placed into new drums, causing the containers to blow off their lids and spewing radioactive waste around the room. No one was injured, in part because the blast happened at about 10:30 p.m. when no workers were inside the building.
Any prohibited items, such as aerosol cans and other potentially flammable materials, must be removed from the waste trays before any repackaged drums can be sent to WIPP, English noted.
The disposition of a prohibited item depends on the type of item and if it can be processed to meet WIPP’s waste acceptance criteria, English said. Material that does not meet that standard is disposed of at a facility authorized to take the waste, he added.
