The Department of Energy’s (DOE) National Nuclear Security Administration (NNSA) has put the brakes on the surplus plutonium Dilute and Dispose program and reassigned K-Area surplus plutonium processing capabilities to the plutonium pit production defense mission. The action marks the end of the latest effort to convert surplus military plutonium into a waste form that is impractical for reuse in nuclear weaponry. Thirty years have now passed since Savannah River Site was selected for long-term—up to 50 years—storage of various surplus plutonium oxides and “non-pit” metals without any meaningful disposition of the materials.

by Don Moniak
July 12, 2026

Since the early 1990’s, when the U.S. declared that approximately 50 metric tonnes of military plutonium was surplus to national security needs (leaving about 45 as nonsurplus), the Department of Energy (DOE) and its “semiautonomous” National Nuclear Security Agency (NNSA, formerly known as “Defense Programs.”) have pursued various means to process the material into a form that is both inaccessible and much less usable for nuclear weaponry.

In January 1997, DOE decided to store all surplus plutonium not contained within plutonium pits at Savannah River Site (SRS)—a total ranging from 11-14 metric tonnes—for up to fifty years. By 2010 approximately 9.5 metric tonnes (1) of the material had been shipped from Rocky Flats and the Hanford site to SRS for storage in the old K-Reactor.

At the same time, DOE settled on a plutonium disposition plan called the dual track, one which involved converting two-thirds of the surplus into nuclear reactor fuel referred to as MOX (mixed-oxide) for use in nuclear reactors, and one-third into ceramic “pucks’ to be encased within the high level waste canisters produced at SRS’ Defense Waste Processing Facility (DWPF); a process called Immobilization.

DOE bailed out on the Immobilization path within five years and then attempted to proceed on the Pu/MOX fuel path alone. This path failed miserably, and in 2018 the final plug was pulled on the program, after a cost of more than $5 billion. Left behind was a shell of a hardened plutonium processing plant that DOE/NNSA is now converting into a plutonium pit production facility.

In 2018, DOE chose a new path, known as Dilute and Dispose, in which the plutonium oxide powder is mixed with a classified blend of “adulterants” that are said to denature the plutonium and make it much less reusable for weapons. The resulting waste material is then packaged and shipped to the Waste Isolation Pilot Plant in New Mexico for disposal in deep salt caverns. (For more information on the Dilute and Dispose program, see Offsite Insights 2022-1).

In August 2020, the State of South Carolina and the Federal Government agreed to a $600 million settlement agreement (2) due to the combination of the MOX fiasco and DOE’s failure to remove any significant amount of surplus plutonium to another state. The settlement now requires DOE to move the 9.5 MT that was shipped into SRS in the early 2000’s to another state by 2036. Failure to do so will result in unspecified fines, or probably an amended settlement agreement.

The Dilute and Dispose program was intended to resolve the issue. But the pace never came close to what was needed to satisfy the settlement, as only a single glovebox line was in place. That pace of work was scheduled to be increased with the addition of two more glovebox lines, but in 2025 DOE/NNSA put the brakes on that effort by shifting funds to the Savannah River Plutonium Processing Facility, a.k.a the Plutonium Pit Plant.

In a letter to the DNFSB regarding tritium safety at SRS, DOE/NNSA wrote that “The Tritium Finishing Facility project was one of three projects paused to redirect funding and personnel to higher-priority projects in the DOE/NNSA complex, including the Savannah River Plutonium Processing Facility (SRPPF), the Los Alamos Plutonium Pit Production Project (LAP4), and the Uranium Processing Facility (UPF), all of which require increased funding to remain on schedule.”

One of the other two projects with funding cuts was the dilute and dispose program. The program was to proceed with its single glovebox line.

Now, according to the Defense Nuclear Facilities Safety Board (DNFSB), the program appears to be on permanent standby, if not altogether cancelled.

In their May 29, 2026, weekly report, DNFSB staff reported that the K-Area Dilute and Dispose facility will undergo a transformation in support of “metal preparation” (3) for plutonium pit production, and recommit to three glovebox lines:

“K-Area Plutonium Metal Preparation (K-PuMP): The RIs received a briefing from SRNS andNNSA personnel on their plans to convert the Surplus Plutonium Disposition (SPD) project in K-Area to a Defense Programs mission (see 4/17/2026 report). The new mission, K-PuMP, will produce plutonium metal feed to support the future Savannah River Plutonium Processing Facility’s and Los Alamos National Laboratory’s pit production. The project will repurpose all three SPD gloveboxes for metal preparation while retaining process flexibility in one glovebox to have the ability to support future SPD mission scope if needed. The change to support plutonium metal preparation includes the addition of new equipment and changes to safety controls, including ventilation modifications, new fire dampers, inert glovebox and glovebox monitoring systems, and nuclear incident monitors for criticality.”

It is unclear whether any surplus plutonium will be reconverted to defense purposes, but the potential is there. SRS currently stores ~2.5 MT of weapons-grade Pu metals and 5.4 MT of weapons-grade Pu oxide powder in K Reactor

Meanwhile, the future of the ~9.0+ metric tonnes of surplus plutonium remaining from past Rocky Flats and Hanford shipments is now subject to new, advanced nuclear power options developed by industry and supported by federal government research and development, direct loans, and other subsidies.

In late May 2025, the Trump administration issued Executive Order #14302 titled “Reinvigorating the Nuclear Industrial Base.” One facet of the order involved the future of surplus plutonium contained within plutonium pits, as well as any other surplus plutonium not a part of the 9.5 metric tons involved in the South Carolina SRS/Plutonium settlement with the federal government.

Section 3(c) of the order states that:

The Secretary of Energy shall halt the surplus plutonium dilute and dispose program except with respect to the Department of Energy’s legal obligations to the State of South Carolina.  In place of this program, the Secretary of Energy shall establish a program to dispose of surplus plutonium by processing and making it available to industry in a form that can be utilized for the fabrication of fuel for advanced nuclear technologies.”

In other words, DOE was still authorized to continue Dilute and Disposte for the 9.0+ tons covered under the settlement agreement. But DOE/NNSA’s decision to end the program for ALL surplus plutonium appears to contradict the provision “except with respect to DOE’s legal obligations to the State of South Carolina.”

In either case, the future of surplus plutonium storage at SRS is shaping up to be more and more like the original 1996 decision of not more than 50 years. South Carolina’s political leadership is more likely to be patient this time around since the future of surplus plutonium again rests in part in the nuclear power industry’s hands (4).

Footnotes:

1. During the closure processes at Rocky Flats, approximately 3.5 to 4.0 tons of plutonium “residues” were processed with some form of Dilute and Dispose and disposed of at the Waste Isolation Pilot Plant in New Mexico, a.k.a the plutonium waste dump. This process greatly reduced the amount of plutonium scheduled for shipment to SRS.

2. For more information regarding the plutonium settlement, see

SRS CAB Might Quit Snubbing Barnwell and Allendale Counties and Offsite-Infrastructure.

For information on the pace of Pu disposition at SRS relative to the settlement, the following was reported in We Will Have to Get Back to You:

“Since fully implementing a program known as “dilute and dispose,” in 2021, only 0.123 metric tons (MT) of the ~10.5 MT of surplus Pu stored at SRS has been processed into a waste form and sent to DOE’s Waste Isolation Pilot Plant (WIPP) in New Mexico for disposal. 

Less than 0.3 metric tons per year are currently being processed at K-Area; much of it awaiting approval for shipment to WIPP. The processing pace is not expected to pick up until after 2030, and only if an $800 million project to add two glovebox processing lines is completed.

3. Section S.2.2. of the Draft Programmatic Environmental Impact Statement for Plutonium Pit Production describes metal preparation as a plutonium purification process:

“Plutonium Purification. Pit-derived (and other older) plutonium is not suitable for new manufacturing—it contains plutonium radioactive decay products (uranium, americium-241, and neptunium-237) and other undesirable characteristics. Therefore, the plutonium will be purified using pyrochemical (nonaqueous) recovery techniques, which generate plutonium-bearing residues that must be either recovered using aqueous techniques or disposed of as TRU waste.

The proposed purification techniques are well known and have been used successfully at DOE sites for many years.

Nonaqueous plutonium metal purification operations could include a combination of the following primary processes: (1) direct oxide reduction, which generally uses calcium metal to reduce plutonium oxide to plutonium metal; (2) molten salt extraction, which uses chloride salts to remove americium-241 from the plutonium; and (3) electrorefining, which uses chloride salts to remove other key impurities from the plutonium metal.”

4. A Request for Applications for usage of the surplus plutonium was issued in October 2025. As of June 2026, DOE’s Office of Nuclear Energy wrote that advanced negotiations are underway.

The RFA described 19.7metric tonnes of surplus plutonium as being available:

The breakdown in locations of these materials was not made available. Below is the 2019 breakdown of surplus Pu stored at SRS:

More information on this process is available from SRS Watch.