The U.S. Nuclear Regulatory Commission is requesting more information about the Energy Department’s plan for closure of a radioactive waste storage tank farm at the Hanford Site in Washington state.
The nuclear regulator will present the request at a DOE public meeting, scheduled for 6 to 8 p.m. May 30 in Richland. The information request is based on the NRC’s review of the Draft Waste Incidental to Reprocessing (WIR) Evaluation for Closure of the Hanford C Tank Farm. The Energy Department is consulting with the NRC, a technical peer reviewer on the draft evaluation, before issuing a final WIR Evaluation for the C Tank Farm.
The Energy Department’s Draft WIR Evaluation is a step toward closure of the 16 single-shell tanks in the C Tank Farm, possibly by having the tanks filled with concrete-like grout and left in place. The WIR Evaluation provides the basis for a determination that the tanks, their ancillary structures, and residual waste meet the WIR criteria in the DOE Radioactive Waste Management Manual to be managed as low-level radioactive waste rather than high-level waste.
The tank waste is left from the chemical reprocessing of irradiated fuel to remove plutonium, and by definition is high-level waste unless it can be shown to meet WIR criteria based on risk and disposal requirements.
Hanford contractors have retrieved more than 1.7 million gallons of waste from the tanks in C Farm, or about 96 percent of the waste volume, and transferred the waste to double-shell tanks. The draft WIR Evaluation shows that grouting the tanks and placing an engineered surface barrier over them would protect workers, the public, and the environment, according to the Energy Department.
The Energy Department is expected to present its responses to the NRC requests for more information at a future public meeting, likely in late summer. The Energy Department could issue a final WIR Evaluation in spring 2020, followed by a WIR determination that could approve the proposed grouting approach.
