A History of Buried Waste at Idaho National Laboratory Site

IDAHO FALLS, Idaho – Just months after the Experimental Breeder Reactor-I began generating electricity in December 1951 in a historic first, the Idaho National Laboratory (INL) Site opened its first waste repository on the 890-square-mile Atomic Energy Commission (AEC) site.

Originally named the “burial ground,” the 13-acre landfill in the south-central portion of the INL Site was constructed to receive radioactive and hazardous waste generated from the reactor and other facilities onsite. The location was chosen because it didn’t have alternating layers of volcanic basalt and soil like most areas of the Arco Desert. Instead, it had more than 25 feet of relatively uninterrupted soil.

Beginning in 1954, the burial ground, later renamed the Subsurface Disposal Area, was expanded to 88 acres and began accepting waste from commercial entities and other AEC sites, primarily the former Rocky Flats Plant near Denver, Colorado. The AEC was a precursor agency to DOE.

Landfill crews used heavy equipment to dig down 25 feet to a basalt layer, backfilled a few feet, and then began hand-stacking barrels and boxes of waste on the clean soil. Due to concerns of personnel exposure, waste eventually was dumped into pits using lifting tractor trailers.

The waste disposed in the landfill that originated from Rocky Flats included graphite molds contaminated with plutonium, air filters, solidified sludges containing radioactive and hazardous constituents, and pyrophoric uranium fines. The landfill also accepted radiological medical waste from throughout the complex, beryllium reflector blocks from an onsite reactor, highly radioactive metal debris, pyrophoric sodium potassium waste, and even common industrial waste such as a pickup truck bed.

For the pits, the disposal process was the same. After several feet of waste was disposed, heavy equipment placed clean soil over the waste and compacted it by driving over the top of it. In an exception to that process, workers constructed an asphalt pad to place containers of nitrate salts. When full, it was covered with clean soil.

In all, approximately 241,000 cubic meters of waste were disposed in 21 pits, 58 trenches and 21 soil vault rows.

In 1970, the AEC changed its policy for the disposal of transuranic waste, opting for above-ground disposal in lieu of burial. Crews constructed a 7-acre asphalt pad southeast of the landfill and began stacking barrels and boxes of waste for the next two decades.