The Department of Energy on June 4 will start taking comments on a draft evaluation on the strategy for closing the 16 tanks in the C Farm radioactive waste storage area.
The announcement of the draft evaluation indicates DOE is interested in landfill closure of the single-shell tanks, likely by filling them with grout and leaving them buried in place. The Washington state Department of Ecology would need to approve any closure plan in a separate permitting process.
Leaving the mostly empty tanks in place is likely to receive at least some pushback. Jack Bell, director of the Environmental Restoration and Waste Management Program for the Nez Perce Tribe, said at a public meeting in April the tribe will not support filling a tank with concrete-like grout and keeping it in the ground. The Nez Perce – who have treaty rights to use of land encompassing Hanford — want the property returned to an uncontaminated condition, which would preclude leaving the tanks behind.
The Energy Department plans to release a draft “Waste Incidental to Reprocessing (WIR) Evaluation for Closure of Waste Management Area C at the Hanford Site” in time for a 96-day public comment period starting June 4. A public meeting will be held on the draft report and the performance report it relies on at a time to be announced June 18 at the Richland, Wash., Public Library.
The draft WIR evaluation is intended to show that the C Farm tanks, ancillary structures, and residual wastes can be safely managed as low-level radioactive waste and disposed of in place. It would evaluate whether waste that remains at the bottom of the tanks is immobilized to keep it from the environment, including keeping it from contaminating groundwater.
Hanford’s tank farms hold 56 million gallons of radioactive and chemical waste that is the byproduct of decades of plutonium, dating to the Manhattan Project, for the U.S. nuclear deterrent.
The draft WIR evaluation is an important step toward closure of the 16 single-shell tanks of the C Tank Farm, according to DOE. The farm is the first at Hanford, which has 149 single-shell tanks, in which tanks have been emptied to regulatory standards. The waste was transferred to double-shell tanks in the AN Tank Farm.
The regulatory goal is to retrieve an average of 99 percent of waste from all single-shell tanks, but DOE can stop retrieving waste when three technologies have been used to get as much material as possible from a tank.
“Achieving closure would be a significant step forward in DOE’s mission to safely, efficiently and cost-effectively clean up the Hanford Site,” DOE said it in a notice of the upcoming comment period. “DOE has a record of successfully closing emptied underground waste tanks at the Savannah River Site in South Carolina and the Idaho National Laboratory.”
The federal agency is consulting with the U.S. Nuclear Regulatory Commission on the draft WIR evaluation and the underlying performance assessment. The assessment will look at the specific constituents of the remaining waste and relate that to the protection of human health.
Public comments and the NRC consultation will be considered before a final WIR evaluation is issued, according to DOE. The final assessment will be issued after the draft evaluation is reviewed, public comments are addressed, and possible revisions are made.
Hanford tank farm contractor Washington River Protection Solutions has been demobilizing retrieval equipment from the C Tank Farm since completing waste extraction from the 16th tank in November. By September, workers are expected to remove the last of 20 transfer lines used to move waste emptied from the C Tank Farm to the AN Tank Farm. The work includes disconnecting and capping the lines form tank pits, splitter boxes, and diversion boxes. The transfer lines, which are hoses inside outer hoses, will be disposed of at the Environmental Restoration Disposal Facility in central Hanford.
