The Department of Energy plans to lay a flexible, durable plastic cover over the berm topping a long-term radioactive waste storage tunnel, where a partial roof collapse was discovered last Tuesday. The work will be done this week, weather permitting, and should take only a couple days, Doug Shoop, manager of DOE’s Richland Operations Office at the Washington state facility, said on Saturday.
Shoop spoke at a press conference after he and other DOE, union, and state officials accompanied Sen. Maria Cantwell (D-Wash.) to the site of the PUREX building tunnel breach in central Hanford.
Hanford crews worked during the weekend to haul in large, concrete ecology blocks that will anchor the plastic covering. Covering the tunnel is an interim step in the stabilization effort
The Department of Energy is discussing further stabilization measures with the state, but no decisions have been made, Shoop said. However, a Washington state Ecology Department account of the briefing with Cantwell said the federal agency is considering whether the tunnel should next be filled with grout.
There has also been no decision on whether a second tunnel, which also was used to store contaminated equipment from the Plutonium Uranium Extraction Plant, will be covered with plastic. While the oldest tunnel was built primarily of timbers, the second waste tunnel was constructed of steel and concrete.
No airborne radiation has been detected since the breach was discovered on Tuesday. The hole has since been filled with a mixture of sand and soil as an initial stabilization step. “We had some very, very high winds after the hole was filled,” Shoop said. “It could be a very different situation if … that hole was still open.”
While DOE has yet to determine exactly when the roof collapse occurred, sampling in nearby tunnels has found no spread of radioactive contamination from the breach, he said.
