The National Nuclear Security Administration said this week there was “no measurable exposure” to workers from a large piece of radioactive metal discovered last month during site preparation for the Uranium Processing Facility.
There have been varying reports about what was uncovered at the UPF site, although occurrence reports submitted by Y-12 contractor Consolidated Nuclear Security indicate there have been more than 50 “events” in which radioactive materials were found over the past couple years.
Steven Wyatt, a spokesman in the National Nuclear Security Administration’s Production Office, said the most recent find on March 9 did not create any worker exposures. “No measurable exposure was received by personnel who worked to dispose of the material found during the excavation work March 9,” Wyatt said via email.
“This contamination was fixed to the metal, and the exposure rate from the metal was not distinguishable from natural background at a distance of a few feet,” he said. “The material had a reading that showed activity roughly equivalent to that found in three household smoke detectors.”
In an earlier response, Wyatt said that even though radioactive materials were not always known in advance at the site, their uncovering during pre-construction activities was “an anticipated project risk.”
According to an official occurrence report filed with the Department of Energy by Consolidated Nuclear Security, the piece of metal uncovered last month was monitored for radiation levels, with total beta-gamma activity measured at 56,665 disintegrations per minute per 100 square centimeters, and 2,457 DPM/100cm2 for total alpha activity.
