OAK RIDGE (MCT) – Road construction associated with the Uranium Processing Facility project was halted temporarily after radioactive materials were uncovered at the work site on the west end of the Y-12 nuclear weapons plant.
Steven Wyatt, a spokesman for the National Nuclear Security Administration, said the radioactive contamination was identified as depleted uranium.
"This debris is considered to be legacy materials from past operations at Y-12," Wyatt said via email.
The radioactive materials, which included old pipes, clay tiles, tree stumps, chunks of concrete, and dirt, were uncovered during work on a haul road that will be used during future construction of the multibillion-dollar UPF. It's expected that many tons of dirt will be excavated and hauled from the site to prepare for the building's foundation.
Road work reportedly was stopped last week after the radioactivity was detected. But Wyatt said the contaminated debris has been segregated and covered with plastic, allowing the road work to continue.
John Eschenberg, UPF's federal project director, made a reference to a "legacy piece of radioactive material" found at the work site during a Feb. 27 speech at the University of Tennessee's Institute for Nuclear Security. That apparently was the same day the radioactivity was detected.
When asked about the finding after his speech, Eschenberg attributed the radioactivity to a piece of concrete. He indicated that the radioactivity might have come from naturally occurring materials. At the time, he said he didn't think it was associated with Y-12 operations. But the radioactive debris appears to be more extensive than that initial report.
Wyatt said some information about the contaminated materials wasn't available at the time of Eschenberg's talk.
The federal spokesman said AVISCO, a subcontractor to the U.S. Army Corps of Engineers doing site preparation for UPF, is working with Y-12's radiation safety specialists to "determine the boundaries of the contamination."
"The contaminated debris has been cordoned off from the rest of the work site," Wyatt said. The 50-foot-by-50-foot area is covered with plastic, he said.
He said the potential for finding legacy contamination at the site was recognized before the road project began on Y-12's west end.
However, Shannon Ashford, a spokeswoman for the Tennessee Department of Environment and Conservation, said the state was told that the area was screened before the project began and that soil contamination was not expected on the north side of Bear Creek Road.
The area where the contamination was found is not in any "exposure unit" in environmental documents that identify radioactive sites for future cleanup activities, Ashford said.
"Samples have been collected to quantify the rad levels," she said in an email statement. Ashford said the state expects additional information that fully describes the contamination and how the NNSA plans to dispose of the material.