Washington Closure Hanford has awarded a subcontract worth $12.3 million to clean up the remaining waste sites in the soil around Hanford's D, DR and H reactors.
TerranearPMC, a small business based in Irving, Texas, that qualifies under Small Business Administration standards as a disadvantaged business, will do the work.
It has an office in Kennewick.
Terranear will be digging up chromium-contaminated soil, some of it down to groundwater about 85 feet deep. The work also includes digging up pipelines used for chemically contaminated waste and some miscellaneous waste sites.
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"We're expecting to remove about 2.5 million tons of material during the course of this subcontract," said Scott Myers, Washington Closure project manager for field remediation at the three reactors.
Similar work to dig up chromium down to groundwater about 85 feet deep was done successfully near Hanford's C Reactor, with much of the work completed this spring.
It was the first time Hanford workers have excavated that deep to remove chemical contamination.
"We will take full advantage of lessons learned from work at C," Myers said.
Hexavalent chromium was added to cooling water at Hanford reactors used to produce plutonium for the nation's weapons program during World War II and the Cold War.
Near the D and DR reactors, which were built near each other along the Columbia River, the chromium has contaminated the soil in three places down to groundwater. The chromium there was spilled or leaked in multiple places from the system that delivered sodium dichromate by railcar and distributed it through a series of pipelines and valve boxes.
The three deep waste sites will be excavated in two digs, one for two of the sites that are near one and other. Digging so deep creates a wide excavation site. At C Reactor, two nearby sites covered the area of about 15 football fields.
H Reactor, one of nine former Hanford production reactors along the Columbia River, is about two miles from the D and DR reactors downriver.
Because the nature of the cleanup work for the sites is so similar, it made sense to combine the work under one subcontract and save taxpayers money, Myers said.
The chrome pipelines, which were near the ground surface, already have been dug up near the reactors. But Terranear will remove deeper pipelines, ranging from 6 inches to 72 inches in diameter, used to carry waste.
The waste had primarily chemical contamination, but they also could have had some radiological contamination, Myers said. The gravity-based systems should have been flushed when taken out of service so they are expected to be empty, he said.
The D, DR and H reactors already have been put in long-term storage to let radioactivity in their cores decay to more manageable levels over 75 years. The reactors have been "cocooned," or torn down to little more than their radioactive cores, reroofed and sealed up.
D Reactor operated from 1944 to 1967 and was cocooned in 2004. DR Reactor operated from 1950 to 1964 and was cocooned in 2002. And H Reactor operated from 1945 to 1965 and was cocooned in 2005.
A previous subcontract at the three reactors resulted in 1.6 million tons of contaminated material removed near the D and DR reactors and 360,000 tons from near H Reactor. That work was completed last summer.
"Removing the chromium contamination is another key step in maintaining the quality of the groundwater and Columbia River," said Carol Johnson, Washington Closure president, in a statement.