More than 2,000 people submitted comments and signed petitions urging the Department of Energy to withdraw a proposal to reclassify the remaining radioactive waste in the Hanford Site’s C Tank Farm as low-level waste. The reclassification would be a step toward allowing DOE to fill the 16 tanks in the tank farm with concrete-like grout and then leave the vessels in place, covered with an engineered barrier to keep out precipitation.
“The federal government’s proposal sets the stage to leave long-lived, dangerous contamination close to the Columbia River at Hanford. The Trump administration’s proposal makes Hanford a high-level waste dump in all but name,” Dan Serres, conservation director for Columbia Riverkeeper, said in a prepared statement.
Columbia Riverkeeper, Hanford Challenge, the Natural Resources Defense Council, and Heart of America Northwest gathered comments and petition signatures in opposition to the DOE Draft Waste Incidental to Reprocessing Evaluation for Closure of Waste Management Area C at the Hanford Site.
The evaluation determined “the small amount of residual waste in the tanks, once stabilized with grout and covered by a surface barrier, would not pose a significant threat,” DOE said in a fact sheet distributed to support a federal public comment period from June 4 to Nov. 7.
The Hanford Site stores 56 million gallons of chemical and radioactive waste in 177 underground tanks, a byproduct of the facility’s former mission to produce plutonium for the U.S. nuclear deterrent.
Waste in Hanford’s storage tanks is legally classified as high-level waste, which is required to be disposed of in a deep geological repository such as the planned Yucca Mountain site in Nevada. Reclassification could allow the waste to be left in place in shallow burial within the tanks.
From 2013 until late 2017, Hanford crews emptied about 96 percent of the waste from the 16 tanks that make up C Farm. The goal was to remove 99 percent of the waste. About 64,000 gallons of waste remains in the tanks after each was emptied to 99 percent or to the limits of three different technologies, including various sluicing systems.
The regional Tri-City Development Council supported the evaluation. The likely alternative would be to spend substantial amounts of money, which could be better used elsewhere at Hanford, to “endlessly try to retrieve the tanks to new standards, and/or to dismantle and remove the tanks at substantial risk to workers,” the organization said in its comment on the proposal. “Even then, those tank materials would likely be re-buried in a landfill elsewhere at the Hanford Site, meaning that a tremendous amount of time and funding would be allocated for very minimal benefit.”
The draft evaluation included a rough cost estimate of $148.5 million for removing additional waste from the 12 larger of the 16 C Farm tanks. Those tanks have a capacity of 530,000 gallons each; the four smaller tanks, not included in the estimate, each have a capacity of 55,000 gallons.
The Washington state Department of Ecology and the Oregon Department of Energy separately submitted comments, with some agreement between the two agencies.
Both questioned whether adding grout to the tanks would meet DOE’s own standards for incorporating waste into a solid physical form, since the grout and waste would not be mixed together. The remaining waste in the tanks is in an uneven layer at their bottoms or clinging to the sides. A break at the bottom of the tank could result in untreated waste being released into the ground, the Department of Ecology said.
The state agencies also said the waste that could be left in grouted tanks should be evaluated in conjunction with waste that has previously leaked or spilled into the ground to better understand the possible combined impacts on groundwater. The Energy Department proposes separate decisions for waste tank residuals and the leaked high-level wastes that are currently migrating toward groundwater beneath the tank farms. It should make a composite analysis available on both before making a final determination on reclassifying waste, according to Oregon.
The state agencies also said the waste that could be left in grouted tanks should be evaluated in conjunction with waste that has previously leaked or spilled into the ground. The Yakama Nation estimated in its comments that about 200,000 gallons of waste has spilled or leaked at the C Tank Farm.
The Oregon Department of Energy said closing the tanks in the near term is not one of its priorities. It would like DOE to evaluate new and more powerful waste retrieval technologies such as stronger pumps or “dry mining” mechanical retrieval technologies to remove solid waste rather than commonly used sluicing technologies. Sluicers spray liquid to break up waste and move it toward a central pump for removal from the tank.
The Yakama Nation, which has historically used Hanford land, said it is opposed to shallow land disposal for tank waste. “It will inevitably result in serious threats to the health of Yakama enrolled members and the public, both by direct exposure and through consumption of contaminated resources,” according to its comment.
The Energy Department has said it will consider the submitted comments and the results of a technical review by the Nuclear Regulatory Commission before it publishes a final evaluation and makes a determination, possibly in the spring. Grouting the tanks would require modification of the Hanford Dangerous Waste Permit issued by the Washington state Department of Ecology, which would require another public comment period before the state agency could make a decision.
The closure of the C Farm tanks could set a precedent for all future Hanford tank farm closures, Ecology said in its comments to DOE on the evaluation. “It will inform how much waste is left behind in all of its 177 tanks and throughout the geologic strata of the tank farms,” the agency said.
