To prevent it from collapsing, the Department of Energy wants to start filling a second PUREX plant waste storage tunnel at the Hanford site with concrete-like grout in August — before the end of a scheduled public comment period about the effort.
The Washington State Department of Ecology, lead state regulator at Hanford, plans a 45-day public comment period and two public meetings on the grouting plan, starting next month. The comment period is expected to run Aug. 13 through Sept. 27.
But DOE has asked the state to authorize 180 days of grouting work by July 23. The state will review the request and respond, Ecology spokesperson Randy Bradbury said.
Bradbury said there is no timeline for the state to act but that regulations require approval or denial as quickly as practical. He also said the state plans to proceed with its public involvement process. The Energy Department already went through its own public comment period.
A shorter PUREX plant waste storage tunnel partially collapsed in May 2017, and DOE has concluded that the second, longer tunnel is also at high risk of collapse.
Ecology will hold its next public meeting on tunnel stabilization at 5:30 p.m. on Aug. 27 at the Richland Public Library. The state agency also set a meeting for 6:30 p.m. on Sept. 5 at the NHS Hall of the University of Washington’s Center for Urban Horticulture in Seattle.
Meanwhile, the Department of Energy said Monday it needs to start work next month to stabilize the second tunnel before winter, when grout trucks would have to travel over icy and snowy roads.
The second, longer PUREX tunnel holds 28 rail cars loaded with highly contaminated equipment.
After it partially collapsed, DOE filled the first PUREX tunnel with 521 truckloads of grout in six weeks. Ecology approved the work without a public comment process, given the emergency conditions. The first tunnel holds eight rail cars loaded with highly radioactive, obsolete equipment from the PUREX plant.
Grouting the tunnels is only an interim stabilization method; DOE has yet to decide on a final cleanup method for the tunnels, and the waste inside them.
The Plutonium Uranium Extraction Plant, PUREX, was used to process irradiated fuel rods to collect plutonium for nuclear weapons during the Cold War. The tunnels store radioactive waste from the PUREX Plant.
Some members of the public have said filling the tunnel with grout makes permanent cleanup of the tunnel or its contents difficult or impossible. State officials have also said grouting is irreversible.
DOE said it selected grouting on the advice of an expert panel assembled to consider options for stabilizing the second tunnel. One option for eventual cleanup would be cutting up the grout within the tunnel based on a detailed plan for where the cuts would be made using water jets, wire saws or excavation equipment. Another option would be building a cap over the tunnel to keep out precipitation and leaving the waste in place.
