OAK RIDGE, Tenn. — A top official at Oak Ridge National Laboratory says at least eight workers received internal radiation while carrying out a classified project earlier this year at the facility.
The Knoxville News Sentinel reports that ORNL Deputy Director Jeff Smith confirmed the Aug. 25 incident, which involved an unexpected airborne release of radioactive material.
Smith characterized the radiation doses as "minor" and said they were well below the level that requires the lab to report the incident to the Department of Energy.
However, he said the lab did report the incident to DOE and conducted a thorough evaluation to prevent a recurrence.
"We never want to have an unplanned radiological exposure," Smith said. "We treat them all seriously."
He said the laboratory was performing the work for the Y-12 nuclear weapons plant and that the incident occurred in a building on the lab's central campus.
The facility contains a number of shielded "hot cells," where radiological work can be performed remotely, but the Aug. 25 activity was not performed in a hot cell or a sealed glovebox.
Smith said the work took place in an "enclosure" but he declined to be more specific. He also said that the radioactive material associated with the exposures was uranium, but he would not discuss what isotopes of uranium were involved or what other materials were involved in the operations.
Officials said there were actually 11 people present during the operation — eight ORNL workers and three observers from Y-12.
According to Y-12 spokeswoman Ellen Boatner, nasal smears and bioassays for the three did not indicate any uptake of radioactive material.
"They were observing (the operation at Building 3525) from outside the radiological area," Boatner said. "They had the advantage of some distance and possibly some shielding."
Smith said some employees at ORNL have jobs in which it's anticipated they'll receive some low-level radiation exposures. The lab tries not to have any unplanned radiation exposures, but it's not unusual for there to be one or maybe two per year, he said.