IDAHO FALLS, Idaho – The Accelerated Retrieval Project I (ARP I), an effort to identify and exhume specific buried waste from a waste repository at the DOE Idaho National Laboratory (INL) Site, began in January 2005.
Excavator operators and waste identification specialists worked in tandem to segregate graphite molds, filters, sludges and reactive uranium from other waste and surrounding soil within two pits of the landfill, named the Subsurface Disposal Area (SDA).
All work took place under a metal-framed, soft-sided building with reverse airflow and extensive high efficiency particulate air (HEPA) filtration. While targeted buried waste retrieval was underway in ARP I, the DOE, U.S. Environmental Protection Agency (EPA) and state of Idaho proposed a second dig area in what would be called ARP II. Construction commenced.
Soon after, an environmental investigation of the entire 97-acre SDA was completed, and the DOE, EPA and state proposed targeted waste retrieval within nine individual dig areas. They also signed a record of decision to remove 7,485 cubic meters of targeted waste from a combined area of 5.69 acres at the landfill.
In pursuant years, seven subsequent dig areas were completed with more than 10,350 cubic meters of targeted waste removed. Crews completed waste exhumation at ARP IX in December last year and finished waste repackaging last month.
With the targeted buried waste exhumation portion of the record of decision completed, the second requirement — construction of an earthen cover over the entire landfill — is scheduled to begin in two years, using soil and gravel from other locations at the INL Site. In total, approximately 3.4 million cubic yards of material will be required to create a cover over an area of approximately 157 acres. A drainage canal will be constructed to divert water from the cover.
Engineers designed the cover to resemble terrain surrounding the waste repository. Following construction, the cover will be seeded with local vegetation, and it will be maintained in perpetuity.
The three government entities agreed that the cover will be in place by 2028, almost 75 years after the Cold War landfill first accepted waste for burial.
The Snake River Plain Aquifer flows 585 feet below the landfill. With the majority of solvents removed from the landfill and a cover in place, water quality in the vicinity of the waste repository is expected to steadily improve.
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