Grouting waste at Hanford

As decommissioning continues at the U.S. Department of Energy (DOE) ’s largest cleanup project at Hanford, much of the disposal of the buildings and equipment takes place at the onsite Environmental Restoration Disposal Facility (ERDF).

And whenever this waste has void spaces that must be filled or requires immobilization treatment, grouting is the go-to solution. Grouting is a process by which a fluid material is pressure-injected into soil, rock or concrete to reduce fluid movement and/or to impart increased strength. Grouts accomplish this through their ability to permeate voids, and gel or set in place.

Recently, ERDF received the 147 glovebox from the 324 Building at Hanford, which supported research on highly radioactive materials from 1966 until 1996. Due to the building’s proximity to the Columbia River and the city of Richland, removing the contamination and demolishing the building is a top DOE priority.

The 147 glovebox has interstitial void space that needs to be eliminated and is RCRA hazardous debris that requires compliant treatment prior to being disposed of in the landfill. The U.S. Environmental Protection Agency gave concurrence to perform treatment at ERDF. The 147 glovebox was placed on a concrete pad and partially encased with free-flowing grout at the end of August. The void spaces will be filled with a special fly-ash grout and allowed to cure, completing the microencapsulation process. After the free-flowing grout cures, the final step will be covering the 147 glovebox with soil.

ERDF has been grouting waste since the late 1990s, but started producing its own grout in 2011, when the batch plant was built as part of an expansion project. ERDF can now produce as much concrete as it needs for on-site grouting. Jim Curnutt, ERDF Waste Management Officer, explains how the process has improved:

“When I arrived in 2006, the grouting process was simply pouring a concrete pad on the floor of the landfill, stacking waste on the cured pad, and covering the waste with free-flowing grout (i.e., flood grout). Grouting waste has evolved into grout injecting almost any packaging, some containing waste streams with extreme levels of radioactive contamination. We’re also capable of introducing free-flowing grout into complex non-standard/non-packaged waste items that were previously shipped offsite for size reduction,” Curnutt said.

IDF is currently in the planning stages to grout inject the melters and bubblers that will be generated at the Hanford Waste Treatment Plant (i.e., vit plant). The process will handle waste streams that will be generated for decades.

Since 2011, the ERDF batch plant has produced just under 24,000 cubic yards of grout – saving taxpayers the cost of purchasing it from an offsite vendor.

CTI-VNSFS Environmental, LLC (CVE) operates the ERDF and the Integrated Disposal Facility at Hanford under a contract to Central Plateau Cleanup Company .? CVE is a U.S. Small Business Administration-approved joint venture of CTI and VNS Federal Services.