IDAHO FALLS, Idaho - The Idaho National Lab released the findings of an inquiry into a 2011 plutonium exposure of 16 of its employees.
In November 2011, the workers were internally exposed to radiation during a fuel-packaging accident.
The analysis performed on the employees was the focus of a meeting on Thursday morning.
After a media briefing, a member of our crew was approached by two lab employees. The men said they were told they could be at the meeting, and said they wanted to speak with us.
At that point, a senior member of INL staff told the men to leave, and escorted them away.
By chance, reporter Caleb James was shooting an interview with Deputy Lab Director David Hill as this was happening. In the video, two employees were escorted away by Materials and Fuels Director of Mission Support Philip Breidenbach.
Reporter Tatevik Aprikyan also heard Breidenbach telling the men there had been a "misunderstanding."
Misty Benjamin, an INL spokesperson, sent us this statement:
"Battelle Energy Alliance (the site's general contractor) is not allowed by law to disclose personally identifiable information of employees involved in the contamination without informed written consent."
She said any employee can speak to the media off-site and outside of work hours.
At the meeting those employees were forced to leave, Breidenbach said, "I want to first say that clearly that event was very unfortunate and doesn't meet our standards for work execution at the INL."
During the 11 months since an accident in November, testing of the radiological effects on 16 INL employees has returned good news.
"There are no observable health effects below 10 rm acute exposure," Breidenbach said.
An "rm" is a measurement of radiation, and Lab Director of Environmental Health and Safety Sharon Dossett said the exposure to all 16 employees was well below a 5 rm annual exposure limit set by federal standards.
"This is the level all industrial workers are allowed to be exposed to," Dossett said.
She said the amount of radiation employees experienced was less than internal Department of Energy standards: a 2 rm maximum.
Breidenbach said the lab has identified 78 corrective measures.
"Many of the corrective actions have been associated with improved work planning," he said. "We've put a lot of effort into improving training."
Breidenbach said more than 50 corrective actions have already been implemented.
On Wednesday, the INL said the workers were instructed to open a storage container called a "clamshell" and prepare the contents for shipment to another DOE facility. After removing four clamshells from storage, but before bringing them into the workroom for the operation, the workers noted that two of the clamshells had atypical labels indicating potential abnormalities with the fuel plates located inside. The immediate supervisor and the nuclear facility manager for the work were consulted, and a decision was made to proceed with the packaging operation. The four clamshells were then taken to the workroom and placed in a fume hood.
When the workers opened the first clamshell, they discovered that the fuel plate inside was wrapped in plastic and tape. While attempting to remove the wrapping material, there was an uncontrolled release and subsequent spread of radioactive contaminants in the workroom.
This release resulted in an exposure of measurable levels of radioactive contamination to the workers, as well as to various facility structures, systems and components inside the ZPPR facility.
We have posted more information from Thursday's media briefing in the "Related Content" section accompanying this story in full-browser view.