RICHLAND, Wash. - The EM Richland Operations Office (RL) is working, in partnership with the Washington State Department of Ecology, on interim stabilization efforts for a tunnel that partially collapsed in May.
The tunnel stores radioactively-contaminated equipment and is located adjacent to the Plutonium Uranium Extraction Facility (PUREX) on the center of the Hanford Site. On May 9, workers discovered the tunnel had partially collapsed. They subsequently filled in the collapsed portion with soil and placed a temporary protective cover over the entire tunnel to further protect Hanford workers, the public and the environment until interim stabilization efforts are complete.
RL and contractor CH2M HILL Plateau Remediation Company (CH2M) will use low-density fill, or engineered grout, to stabilize Tunnel 1. Grouting makes Tunnel 1 safer for eventual dispositioning, and supports long-term dispositioning of PUREX and associated tunnels. EM has used grout to stabilize other legacy structures at Hanford.
“Grouting of the tunnel eliminates the immediate hazard," said RL Manager Doug Shoop. He added that the grout solution will improve the structural integrity of the tunnel and prevent further collapses.
Crews will access the tunnel through existing ports or new penetrations along the tunnel. Using hoses, workers will deposit the loose-flowing grout through the ports into the tunnel, filling the tunnel in several layers.
Grouting is expected to be completed by November, before winter weather can potentially add more stress to the tunnel.
“We’re trying not to subject the tunnel to another hard winter or any further stress than we have to," said Ty Blackford, CH2M’s president and chief operating officer. “We want to move safely, smartly and quickly to accomplish this."
Source: U.S. Dept. of Energy, Office of Environmental Management
