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Nuclear Waste Disposal: Actions Needed to Enable DOE Decision That Could Save Tens of Billions of Dollars

GAO-22-104365 Published: Dec 09, 2021. Publicly Released: Dec 09, 2021.
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Fast Facts

The Department of Energy manages 54 million gallons of nuclear and hazardous waste at its Hanford site in Washington state. DOE has treatment options for some of its low-activity waste:

  • Vitrify it—immobilize it in glass (current plan)
  • Grout it—immobilize it in a concrete-like mixture (potential option)

Grouting the waste could save billions of dollars, and several facilities could dispose of it. But DOE faces legal challenges if it tries to dispose of grouted waste.

We recommended that DOE look at disposal options for grouted waste and suggested that Congress consider clarifying DOE's authority to manage and dispose of low-activity waste.

Vitrifying nuclear waste (left) may cost billions of dollars more than grouting it (right).

side-by-side images of vitrified and grouted nuclear waste

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What GAO Found

Several potential options exist for disposing of grouted supplemental low-activity waste (LAW) from the Department of Energy's (DOE) Hanford site. (Grout immobilizes waste in a concrete-like mixture.) Specifically, two commercial and two federal facilities present minimal technical challenges to accepting grouted LAW. The commercial facilities—Clive Radioactive Waste Disposal Facility in Utah and Waste Control Specialists in Texas—are licensed to receive similar waste. The federal facilities—Hanford's Integrated Disposal Facility and the Nevada National Security Site—face regulatory constraints and other challenges to disposing of grouted supplemental LAW.

Disposal costs and health and environmental risks vary among the four potential disposal facilities, but disposing of Hanford's supplemental LAW as grouted waste could cost billions less than disposing of it as vitrified waste, which is DOE's current plan. (Vitrification immobilizes the waste in glass.) DOE estimated that vitrification and disposal of the waste would cost between $21 billion and $37 billion. GAO estimated grouting and disposal would cost between $11 billion and $13 billion (see figure) and may be faster. DOE has begun exploring how to dispose of grouted Hanford waste, but it has not analyzed a range of options as GAO and DOE best practices recommend. As a result, DOE is likely missing opportunities to reduce risks, expedite treatment, and save tens of billions of dollars.

Figure: Estimated Total Costs for Treatment and Disposal of Vitrified and Grouted Supplemental Low-Activity Waste

Figure: Estimated Total Costs for Treatment and Disposal of Vitrified and Grouted Supplemental Low-Activity Waste

DOE faces legal challenges in selecting a disposal site if it grouts supplemental LAW. For example, before DOE can consider alternatives to vitrification, it must show it can manage Hanford's tank waste as a waste type other than high-level waste (HLW) because it is currently required to vitrify at least a portion of the HLW. DOE is testing alternative treatment and disposal options, but DOE officials told GAO that if they continue with the testing, they expect the effort to be the subject of litigation. Clarifying DOE's authority to manage Hanford's supplemental LAW as low-level waste and transport it outside Washington State for disposal could help save tens of billions of dollars by allowing DOE to pursue less expensive disposal options.

Why GAO Did This Study

DOE oversees the treatment and disposal of 54 million gallons of nuclear and hazardous waste at the Hanford site in Washington State. Hanford's tank waste is currently managed as HLW; however, more than 90 percent of the waste's volume has low levels of radioactivity. DOE plans to vitrify a portion of Hanford's LAW, but it has not made a decision on how to treat and dispose of the roughly 40 percent referred to as supplemental LAW. In May 2017, GAO found that grouting supplemental LAW could save tens of billions of dollars and reduce certain risks compared to vitrification. However, little is known about disposal options for grouted LAW.

GAO examined (1) what potential disposal options exist for grouted supplemental LAW, (2) what is known about the costs and environmental risks of potential disposal facilities and the extent to which DOE has assessed them, and (3) the challenges DOE faces in selecting a disposal method. GAO reviewed technical reports on DOE's waste disposal strategies at Hanford, compared DOE's approach to best practices, and interviewed DOE officials and disposal facility representatives.


Congress should consider clarifying two issues, including DOE's authority to manage and dispose of the tank waste as other than HLW, consistent with existing regulatory authorities. GAO also recommends that DOE expand the potential disposal options it assesses to include all facilities that could receive grouted supplemental LAW. DOE concurred with GAO's recommendation.

Matter for Congressional Consideration

Matter Status Comments
To enhance DOE's ability to make risk-informed decisions for the treatment of Hanford supplemental LAW, Congress should consider clarifying, in a manner that does not impair the regulatory authorities of EPA and any state, DOE's authority to determine, in consultation with NRC, whether portions of the tank waste that can be managed as a waste type other than HLW and can be disposed of outside the state of Washington. (Matter for Consideration 1)
As of January 2024, Congress has not passed legislation that would implement this matter.
In support of the Test Bed Initiative and in a manner that does not impair any state's authority to determine whether to accept waste for disposal, Congress should consider (i) authorizing DOE to classify the volumes of waste corresponding to the second phase of the Test Bed Initiative for out-of-state disposal as something other than HLW and (ii) specifying that RCRA's HLW vitrification standard does not apply to this volume of waste. (Matter for Consideration 2)
As of January 2024, Congress has not passed legislation that would implement this matter.

Recommendations for Executive Action

Agency Affected Recommendation Status
Department of Energy
Priority Rec.
The Secretary of Energy should direct the Assistant Secretary for Environmental Management to expand future analyses of potential disposal options to include all federal and commercial facilities that could potentially receive grouted supplemental LAW from Hanford. (Recommendation 1)
Closed – Implemented
Section 3125 of the 2021 National Defense Authorization Act instructed DOE to expand its study of options for treating and disposing of the supplemental low-activity waste at the Hanford Site. DOE convened a Federally Funded Research and Development Center (FFRDC) to conduct this review. In January 2023, the FFRDC published the first volume of results of an ongoing review. This report describes DOE's analysis of potential disposal options for grouted low-activity waste, including off-site options outside of the State of Washington, as we recommended.

Full Report

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