Energy Department officials say exhumation work remains well ahead of schedule at the Idaho National Laboratory’s Radioactive Waste Management Complex, where transuranic waste generated from nuclear weapons manufacturing was buried in the 1950s and 1960s.
Officials last week said they have exhumed 4.5 acres of a minimum requirement of 5.69 acres of “target” waste since 2005. The waste is located at a 97-acre unlined landfill called the Subsurface Disposal Area (SDA). Contractor Fluor Idaho last summer surpassed a second requirement on the project, when it packaged at least 7,485 cubic meters of waste from the SDA.
The acreage and volume cleanup requirements were included in a 2008 cleanup agreement between Idaho, DOE, and the Environmental Protection Agency, targeting certain high-risk waste areas of the landfill with the aim of protecting the Snake River Plain Aquifer. The targeted waste includes sludges, graphite, and filters contaminated with plutonium from the old Rocky Flats Plant near Denver.
Fluor officials say they expect to finish the exhumation operations well ahead of a February 2020 deadline in their contract. The contract deadline is about two years before DOE officials initially expected to complete the job, said Jack Zimmerman, DOE’s Idaho Cleanup Project deputy director. Both Fluor and previous contractor CH2M-WG Idaho have made fast progress at the SDA, he said.
The exhumation, using heavy machinery, has been conducted under large metal and fabric Accelerated Retrieval Project (ARP) enclosures, which prevent outside contamination and allow cleanup work to continue through winter. The ninth and final such enclosure is expected to be finished by early summer, officials said. Idaho Falls-based contractor North Wind is conducting the $11 million enclosure construction project under a DOE small business set-aside contract awarded last year.
The new ARP enclosure will cover nearly three-quarters of an acre. It will connect to older enclosures nearby that have existing infrastructure for sorting and packaging waste that comes out of the landfill.
ARP No. 8 is the only other enclosure in which waste is still being exhumed, and work there is about 70 percent complete, said Jason Chapple, a senior project manager for Fluor.
The packaged waste is destined for the Waste Isolation Pilot Plant in New Mexico, though like transuranic waste at the nearby Advanced Mixed Waste Treatment Project and elsewhere around the country, it has been stranded since a pair of 2014 accidents at WIPP. The facility resumed waste emplacement operations in December, but for the moment is clearing out material that was stranded above-ground at WIPP following the incidents.
This year’s exhumation budget is $22 million; the full 5.69 acres of waste removal is expected to have cost about $1.3 billion by the time a soil cap is built over the landfill in the mid-2020s to prevent moisture from leaking through to the aquifer.
