Todd Jacobson
NS&D Monitor
6/6/2014
The Defense Nuclear Facilities Safety Board is seeking more information about a National Nuclear Security Administration analysis of the effects of trips and falls on special tooling used in nuclear explosive operations at the Pantex Plant. In a June 2 letter to NNSA Administrator Frank Klotz, DNFSB Chairman Peter Winokur said the Board wants a briefing from the agency in 45 days on the results of recent "falling man" experiments, as well as information on immediate compensatory measures and actions that will be taken as a result of the analysis.
Winokur said the NNSA and B&W Pantex have "not demonstrated that the special tooling used in nuclear explosive operations at Pantex adequately protects the public and workers from the potential consequences of a falling man event. B&W’s analysis of the falling man hazard does not bound the accident conditions to which a nuclear explosive could be subjected." Winokur said 10 Nuclear Explosive Safety evaluations since 2006 have documented concerns related to a 2002 analysis of "falling man" accidents, and he noted that 2012 experiments conducted by contractors and Virginia Tech University revealed that the existing analysis "may underestimate the load and energy of the falling man by a factor of five or more," and that there are several pieces of tooling for which "credible falling man scenarios remain unanalyzed."
The Board also raised concerns about falling man events in its 2013 annual report submitted to Congress in 2013, noting that NNSA management in August of 2013 downgraded findings by a Nuclear Explosives Safety Study Group that called for immediate action on potential shortfalls in the analysis of falling man events. In November, the Board said NNSA officials said the Board’s views were being considered. In a statement, NNSA spokesman Derrick Robinson said the recent NNSA analysis of falling man events "serves as an example of our continuous efforts to improve and validate these models, working to ensure that they are as accurate as possible." He said safety measures implemented at Pantex "continue to ensure its safety" while the analysis is completed. "We will continue to work with the Safety Board to update our models and ensure that our operations are well characterized," he said.
