The Idaho Department of Environmental Quality is reviewing Fluor Idaho’s plan to restart sludge waste repackaging at the site where four drums of radioactive waste overheated and blew off their lids at the Energy Department’s Idaho National Laboratory a year ago.
The state agency received formal submittal of the corrective action plan last Thursday and hopes to complete its review in the near future, Brian English, DEQ hazardous waste permits manager, said in a Monday email. Fluor Idaho hopes to resume packaging in the next few weeks.
The four drums spilled radioactive material inside the Accelerated Retrieval Project No. 5 (ARP-5) facility within the lab’s Radioactive Waste Management Complex around 10:30 p.m. on April 11, 2018. In an October analysis, Fluor Idaho said the temperature inside the drums increased to about 150 degrees Celsius after depleted uranium contacted air for the first time in years. Also, material from the drums generated methane, a flammable gas.
The 55-gallon drums involved in the accident contained sludge waste generated decades ago at the old Rocky Flats nuclear weapons plant near Denver. The waste, buried on-site at the Idaho National Laboratory for years, were being repackaged inside the ARP fabric filter building. This involves removing the contents from the old drums and removing any potential sources of ignition before placing the material into new drums.
In its filing with the state, Fluor Idaho said it plans longer, more extensive thermal monitoring to spot temperature increases in sludge waste more quickly, additional raking with equipment will be used to better disburse material that could ignite, and screening the contents of each old drum one at a time on the sorting table.