NS&D Monitor
10/30/2015
Contractor Criticality Safety Infraction Reported at Sandia
A contractor in September caused a criticality safety breach that forced the evacuation of a section of the Sandia National Laboratories, according to a Defense Nuclear Facilities Safety Board site representative report released this month.
The worker was taking measurements at the SNL Annular Core Research Reactor facility on Sept. 8 while preparing to install an air compressor and piping. In doing so, he moved a wheeled safe without receiving authorization from lab staff, the report says. “The safe contained fissile material and was moved within the designated criticality safety stand-off distance for other fissile materials located in the High Bay,” DNFSB officials said.
The high bay was evacuated as soon as the situation was identified, but criticality safety engineers then determined the restricted amount of fissile material in the area meant “there was no imminent danger of a criticality” – an uncontrolled nuclear chain reaction.
The lab commenced a causal analysis of the incident on Sept. 10 and on Sept. 11 reported the breach “as a degradation of controls for criticality safety in an Occurrence Report,” the DNFSB monthly site report says.
The lab has taken steps to prevent future incidents of this type, including having staff escort contractors who are working in the high bay and placing wheel clamps on the safe.
