RICHLAND, Wash. - Imagine coordinating hundreds of trucks delivering more than 4,400 cubic yards of grout night and day for weeks.
That was the task of workers on the Hanford Site who safely completed the stabilization of a partially collapsed waste storage tunnel Nov. 11.
Before the first truck of grout arrived, planning, testing, and practice runs took place over several weeks to prepare approximately 50 workers to place engineered grout in Tunnel 1 near the site’s Plutonium Uranium Extraction Plant.
EM Richland Operations Office contractor CH2M HILL Plateau Remediation Company (CHPRC) managed the grout placement. A team from CHPRC and subcontractor Intermech developed a mockup of the tunnel site at Intermech’s facilities, allowing the crew to fine-tune the grout formula in a non-radioactive environment and test equipment for grout placement.
Workers built and tested an 80-foot flume box at American Rock, a local company that supplied the grout, and four grout test pours were done there to ensure the material would adequately flow the length of the 360-foot tunnel. The team that conducted the mockups also placed the grout.
“Our singular focus was to safely fill the tunnel with grout," said Andre LaBonty, CHPRC manager for the grouting project. “We had a skilled and dedicated team from day one. Careful planning and orchestration ensured safety of employees around the moving concrete trucks and a smooth flow of traffic."
The tunnel, holding eight rail cars containing legacy plutonium processing equipment, partially collapsed May 9, but was immediately stabilized with sand and soil. Grouting the entire tunnel eliminated a potential threat of further collapse, while protecting workers, the public, and the environment from radiological hazards, yet not precluding future remedial actions or final closure decisions.
Source: U.S. Dept. of Energy, Office of Environmental Management
