DNFSB Wants to Know How DOE Plans to Address Volcanic Ashfall Hazards at WTP

The Defense Nuclear Facilities Safety Board is concerned that the Department of Energy is not adequately preparing the Hanford Waste Treatment Plant for the potential threats posed by volcanic ash, according to a letter the Board sent DOE late last week. The WTP’s current design and safety basis do not include the most recent assessment prepared by the U.S. Geological Survey that found a significant increase in ashfall parameters from previous estimates, DNFSB Chairman Peter Winokur wrote in the Oct. 23 letter to acting Assistant Energy Secretary for Environmental Management Mark Whitney, asking the Department to provide within 90 days a response on DOE’s “intent and plan” for incorporating the updated ashfall hazards analysis. “The lack of an ashfall control strategy based on the latest hazard assessment, concurrent with design activities, may lead to the need for significant new designs, design revisions, or retrofits to already-constructed systems,” Winokur wrote.

According to the Board, DOE earlier this year rescinded direction provided to WTP contractor Bechtel National to evaluate the impacts of the updated ashfall hazards analysis. “DOE-ORP personnel explained that they would like BNI to first resolve open technical issues that include the necessary controls for safe hydrogen gas release, the air requirement to support pulse jet mixing, and the subsequent realignment of the design and safety basis. After the resolution of these technical issues, DOE-ORP intends to direct BNI to finalize its previous control strategy with the ashfall loads from the baseline analysis and then to evaluate the impact of incorporating the new ashfall analysis into the design and safety basis,” states a Board staff report. The report goes on to warn, “By continuing design activities without incorporating the latest assessment of the hazard, the project is not meeting the requirement of DOE Order 420. lB, Facility Safety, as listed in the WTP Code of Record, to design and construct facility SSCs to withstand natural phenomena hazards and ensure protection of the public.”

The DOE Office of River Protection, which oversees the Hanford vit plant project, did not respond to a request for comment yesterday on the Board’s letter. However, according to a recently released DNFSB site representative report, dated Sept. 19. the Office of River Protection has formed an “Ashfall Working Group” to identify “sustainable options” for addressing the ashfall hazard. The working group is “evaluating and attempting to refine the magnitude of the ashfall hazard” and is “identifying potential design options to mitigate the increased hazard,” the site representative report says.