Energy Department contractor Fluor Idaho has resumed treatment of the remaining sludge waste at the site of an April 11, 2018, accident at the Idaho National Laboratory in which four storage drums overheated and blew off their lids.
Work at the Accelerated Retrieval Project 5 (ARP-5) facility at the Idaho Cleanup Project “has progressed safely with additional worker protections and waste processing procedures,” company spokesman Erik Simpson said by email Friday. He did not specify when treatment resumed.
The Idaho Department of Environmental Quality signed off on resumption of repackaging in an April 25 letter. The anticipated work in the Waste Management Facility-1617 area includes processing and repacking waste from 27 trays, along with about two dozen separate drums in various stages of overpacking or vacuuming, according to the letter from DEQ’s hazardous waste bureau chief, Natalie Creed, to Nicole Hernandez with the Energy Department’s Idaho Operations Office.
Sludge waste from the old Rocky Flats nuclear weapons plant in Colorado was at the ARP 5 site for repackaging during the April 2018 event, which Defense Nuclear Facilities Safety Board Chairman Bruce Hamilton has likened to an explosion.
The sludge waste was buried at INL for years before workers opened and then repackaged the material into four drums that overheated and blew off their lids on April 11, 2018. Repacking is one of the steps taken before the material can be certified for shipment to the Waste Isolation Pilot Plant in New Mexico.
When the four drums ruptured, they spewed radioactive sludge waste around the room. Fluor Idaho expects to complete processing and repackaging the remaining waste at the accident site in June, according to the company’s latest monthly report to the state on the drum event, submitted April 30.
Once repackaging is done, the ARP 5 facility will be permanently closed to further waste treatment, Simpson said. Fluor Idaho informed the Idaho DEQ it intends to resume sludge drum treatment late this summer in ARP 7, which is also a permitted Resource Conservation and Recovery Act facility with proper air filtration.
In an October analysis, the contractor said the temperature inside the affected drums rose to about 150 degrees Celsius after depleted uranium contacted air for the first time in years. Material from the drums generated methane, a flammable gas. No one was hurt, in part because the incident happened about 10:30 p.m. with nobody inside the fabric filter building.
The accident has drawn scrutiny from the DNFSB as well as Congress. The DNFSB has promised a hearing on the accident this spring. Fluor Idaho has the five-year, $1.6 billion Idaho Cleanup Project contract, which runs through March 2021.
