GAO: Grouting Hanford tank waste could cost more than $1.1B

Grouting Hanford's low-level radioactive liquid tank waste could cost between $480 million and $1.1 billion, according to a report by the Government Accountability Office, which has repeatedly found that grouting (immobilizing waste in a concrete-like mixture) can accelerate cleanup at the Hanford Site and save billions of dollars when compared to mixing the waste with molten glass through the vitrification process.

Under a 2025 agreement with the Environmental Protection Agency and the state of Washington, the Department of Energy is to grout a portion of low-activity tank waste (LAW) at the Hanford Site near Richland, Wash. Hanford has about 55 million gallons of mixed radioactive and chemical tank waste resulting from legacy weapons production stored in 177 underground tanks.

According to the GAO report Hanford Cleanup: DOE's Plans to Grout and Dispose of Millions of Gallons of Tank Waste (GAO-26-108878), released on May 20, the DOE is pursuing options to grout about 24 million gallons of LAW (including liquid added during the retrieval and pretreatment process) from 22 tanks in Hanford's 200 West Area. The waste would be off-site for disposal by 2040.

The DOE is currently evaluating proposals from companies willing to grout and dispose of the tank waste, either by designing and constructing a new on-site grouting facility or by shipping liquid waste to be grouted off-site. According to the GAO report, the DOE plans to award one or more contracts for this work later this year.

Price comparison: Per gallon, it would cost between $20 to $45 to grout the 24 million gallons of LAW, the GAO reported, although the estimate does not include additional costs, "such as transportation, disposal, and the need to address potential organic materials that were added during waste extraction operations and remain in a portion of the waste."

In comparison, a 2023 GAO report found that it would cost an estimated $1,400 per gallon to vitrify the waste. According to that report, the DOE "could save approximately $95 billion (escalated) over the next 50-60 years by grouting a portion of the LAW rather than vitrifying it."

Caveat: The DOE is constrained in pursuing alternative treatment and disposal options for Hanford's tank waste, as the waste is managed as high-level radioactive waste as a matter of policy. The GAO has recommended that Congress clarify the DOE's authority to determine whether portions of Hanford's waste can be managed as something other than HLW.

Vitrification update: The DOE's Office of Environmental Management announced in May that Hanford had successfully solidified more than 100,000 gallons of tank waste into glass at the Low-Activity Waste Facility, part of Hanford's Waste Treatment and Immobilization Plant (WTP), also known as the Vit Plant.

A team led by Vit Plant contractor Bechtel has operated the facility in extended hot commissioning since October 2025. According to DOE-EM, the hot commissioning process will continue over the next year, during which time the team "will build production consistency and establish a steady rhythm for safe and sustained operations."

Following hot commissioning, Bechtel will turn the LAW Facility over to DOE operations contractor Hanford Tank Waste Operations and Closure (H2C) for regular operations.

In the vitrification process, radiological and chemical waste is combined with glass-forming materials in the LAW Facility's two 300-ton melters and then heated to 2,100°F. The waste is then sealed in stainless steel containers, each of which is 4 feet wide and 7.5 feet tall and weights approximately 7 metric tons when filled. The containers are delivered to Hanford's Integrated Disposal Facility for long-term disposal.

"Treating 100,000 gallons is more than just a number; it represents our commitment to protecting the Columbia River and Tri-Cities community for future generations," said Mat Irwin, Hanford Field Office assistant manager for tank waste operations.