Grouting Waste

Testing New Approaches for Tank Waste Treatment

The Hanford Site faces one of its most complex challenges — the safe disposal of approximately 56 million gallons of radioactive and chemical tank waste. According to the Department of Energy’s Office of Environmental Management (DOE-EM), this is one of the most technically demanding cleanup tasks in the nation.

This mission is also the largest cost driver at Hanford, with current lifecycle estimates ranging from $199 billion to $496 billion.

The Current Waste Treatment Strategy

Hanford’s 177 large underground tanks hold a mix of high-level waste (HLW) and low-activity waste (LAW). The current cleanup plan involves:

  • Retrieving tank waste and separating it into HLW and LAW streams.

  • Processing HLW and about half of the LAW at the Waste Treatment Plant (WTP) through vitrification — turning the waste into solid glass for safe storage.

  • Storing vitrified LAW permanently at Hanford.

  • Shipping HLW to a future deep geological repository.

The Supplemental LAW Challenge

The remaining 15–20 million gallons of LAW — called Supplemental LAW (SLAW) — does not yet have a final treatment method. To explore options, DOE launched the Test Bed Initiative Phase II (TBI) 2,000-Gallon Demonstration Project.

This project tests whether grouting — mixing the waste with a concrete-like material that solidifies and immobilizes it — could be a safe, cost-effective alternative to vitrification. Grouted waste could be permanently disposed of at licensed commercial facilities outside Washington State.

Potential Benefits of Grouting

  • Cost Savings: The Government Accountability Office estimates grouting SLAW could save up to $95 billion.

  • Time Savings: Grouting could significantly shorten the overall cleanup timeline.

  • Flexibility: Provides an alternative if vitrification capacity is limited.

Holistic Negotiations Agreement – April 2024

In April 2024, the U.S. Department of Energy (DOE), Washington State Department of Ecology, and U.S. Environmental Protection Agency (EPA) announced a landmark agreement outlining a “realistic and achievable plan” for cleaning up millions of gallons of tank waste.

Key commitments include:

  • Retrieving waste from 22 tanks in Hanford’s 200 West Area by 2040.

  • Grouting the low-activity portion of that waste for offsite disposal.

  • Continuing to prioritize safe, effective cleanup strategies.

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