DNFSB Calls on DOE to Provide More Info on Preventing Hydrogen Explosions at WTP

The Defense Nuclear Facilities Safety Board is calling on the Department of Energy to provide more information on how it intends to prevent potential hydrogen explosions in a portion of the Hanford Waste Treatment Plant. Currently, the Safety Design Strategy for the WTP’s High-Level Waste Facility “does not define a nuclear safety control strategy for hydrogen explosion hazards following the loss of mixing in process vessels containing non-Newtonian waste,” DNFSB Vice Chair Jessie Roberson wrote in a Jan. 21 letter to acting Assistant Energy Secretary for Environmental Management Mark Whitney. “The WTP project previously developed a well-defined control strategy that relied on spargers to periodically agitate the waste to reduce accumulated hydrogen,” Roberson wrote. “However, the spargers have been eliminated from the SDS control strategy due to challenges with meeting the ventilation system requirements.”

According to the Board, WTP contractor Bechtel National plans to rely on work being done to resolve “similar hazards” at the WTP Pretreatment Facility to aid in the development of a safety control strategy for the High-Level Waste Facility. However, Roberson wrote, “Due to significant differences in the design of the mixing systems and waste properties at these facilities, evaluations for the PT Facility may not be applicable to the HLW Facility.” The Board has asked DOE to provide within 90 days a report on the Department’s path forward for a nuclear safety control strategy for hydrogen explosions at the High-Level Waste Facility.