U.S. nuclear warhead assembly operations at a Tennessee facility were temporarily suspended earlier this year after a worker improperly used hand-copied notes from the wrong specifications document, the Knoxville News Sentinel reported today (see GSN, Aug. 15).
Operations have since resumed at the Y-12 facility in Oak Ridge after a review concluded that the safety violation was not a systemic problem.
“It’s an isolated incident,” said Thomas D’Agostino, head of the Energy Department’s National Nuclear Security Administration, while praising the worker for self-reporting the event.
While assembling a warhead, the worker improperly used a handwritten crib sheet onto which he copied part sizes from a different nuclear-weapon component than the one he was working on, according to a report by the Defense Nuclear Facilities Safety Board that was completed Aug. 15, but not publicly released until recently.
A Y-12 spokeswoman did not say whether the worker had been disciplined, nor did she identify the warhead that was being assembled. However, the incident took place at a time the facility was conducting refurbishment of W-76 warheads for submarine-based Trident missiles, according to the News Sentinel.
The safety board criticized the worker for making the crib sheet, but also identified some weaknesses in allowed procedures.
“A contributing factor was that work control processes allow the operator to handle several specification sheets for different weapon builds as opposed to requiring handling of only the specification sheets for the specific unit being assembled,” the report says (Frank Munger, Knoxville News Sentinel, Oct. 10).