Exterior view of ORNL’s Building 3525, where an Aug. 25 incident resulted in internal radiation exposures to at least eight workers.
At least eight workers received internal radiation doses while carrying out a classified project earlier this year at Oak Ridge National Laboratory.
ORNL Deputy Director Jeff Smith confirmed the Aug. 25 incident, which involved an unexpected airborne release of radioactive material. But he said he couldn’t discuss details because of the classified nature of the work. The laboratory was performing the work for the Y-12 nuclear weapons plant, he said.
Workers who inhaled radioactive particles were monitored for an unspecified period following the incident, using biological samples to determine their internal exposures. The highest dose was calculated to be 230 millirems.
Smith characterized the radiation doses as “minor” and said they were well below the level — 500 millirems — that requires the lab to report the incident to the Department of Energy. The lab did, however, report the “unplanned radiological uptake” to DOE and thoroughly evaluated the incident to help prevent a recurrence, he said.
“We never want to have an unplanned radiological exposure,” Smith said. “We treat them all seriously.”
The ORNL official said the incident occurred in Building 3525 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.
According to Smith, the work was taking place in an “enclosure” but he declined to be more specific.
All told, there were 11 people present during the operation — 8 ORNL workers and 3 observers from Y-12, he said.
Smith indicated that all of the individuals received detectable doses of radiation, but referred questions to Y-12 for information on the three observers. 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,” she Boatner said. “They had the advantage of some distance and possibly some shielding.”
Smith confirmed 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.
“I’ll just tell you it had uranium in it,” he said.
One unconfirmed report indicated that the workers may have been sawing material or otherwise reducing the size of pieces, but Smith would not comment on that report.
He said it’s not uncommon for ORNL to be doing work for Y-12.
“We have done work for Y-12 for a long time,” Smith said. “They tend to access us for all sorts of support. We try to be helpful when we can.”
The ORNL official said the workers were wearing protective gear that was considered appropriate for the project, but things didn’t go as planned.
Workers realized there was airborne radioactivity when alarms sounded, and they evacuated the area, Smith said. After that, proper procedures were followed to determine the workers’ exposures.
They are no longer being monitored, he said.
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 doses, but it’s not unusual for there to be one or maybe two per year, he said.
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