An interesting article on the use of weapons grade Pu (i.e. 239Pu) as a substitute for HALEU.

https://nationalinterest.org/blog/energy-world/how-the-united-states-can-turn-cold-war-plutonium-into-advanced-nuclear-power

Not sure whether ²³⁹Pu is immediately substitute for HALEU (i.e without proving up the fuel) but only 34Tonnes would only be sufficient for the early loads but would provide time for opportunity 3 (HALEU) at the PLEF (LEU (opportunity 2) and NUF6 (opportunity 1)) and some competition to Centrus/Urenco in the early days of Gen 4 SMR fuels.

How the United States Can Turn Cold War Plutonium into Advanced Nuclear Power

May 19, 2025

By: Paul J. Saunders

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Repurposing surplus plutonium as reactor fuel could cut costs, ease the advanced nuclear fuel bottleneck, and offer a more permanent nonproliferation solution than dilute and dispose.

America has some big decisions to make in its nuclear policy. Some of the most important relate to handling plutonium and to exploiting its value as fuel for advanced nuclear reactors.

For over a decade, the Department of Energy (DOE) has pursued the “dilute and dispose” method as the default strategy for dealing with thirty-four metric tons of surplus weapons-grade plutonium. This method, which involves mixing the material with inert substances and burying it deep underground at the Waste Isolation Pilot Plant (WIPP) in New Mexico, has been promoted as a practical non-proliferation measure. But dilute and dispose has turned out to be expensive and inefficient. Using this surplus plutonium as fuel is a smarter, safer, and more forward-looking approach.

Ending the wasteful dilute and dispose program and pivoting to plutonium fuel use in advanced reactors would not only save taxpayers money but also accelerate the elimination of plutonium, strengthen America’s energy security, and enhance global non-proliferation efforts. It is a bipartisan-supported opportunity to turn a Cold War liability into a clean energy asset.

The Cost Case: Waste vs. Value

Dilute and dispose was intended to be a cost-effective alternative to the now-cancelled Mixed Oxide (MOX) Fuel Fabrication Facility. But costs have continued to climb. DOE’s own cost estimates have risen to over $19 billion for the dilute and dispose program, with additional delays and long-term storage costs likely. WIPP, the disposal facility intended to house the diluted plutonium, has limited space and is already under strain from other federal waste streams.

Using surplus plutonium as reactor fuel offers the opportunity to turn that expense into value. Advanced reactors, such as fast reactors or molten salt designs, can use diluted plutonium as fuel directly. Rather than burying it in costly disposal facilities, we can burn it to produce energy. Leveraging government fuel supplies could reduce the cost of advanced nuclear power and save ratepayers billions of dollars on their utility bills, while strengthening the reliability of the grid with next-generation nuclear technology.

DOE and the American nuclear industry are already investing in advanced reactors to meet both short- and long-term clean energy needs. Repurposing the plutonium stockpile would provide a ready, domestically available fuel source for these investments, helping reduce the cost of deployment and easing the fuel bottleneck that currently limits the pace of advanced reactor commercialization. Increased access to fuel is especially critical now, as domestic uranium enrichment capacity is only just beginning to rebuild.

Accelerating Plutonium Elimination

One of the primary arguments in favor of dilute and dispose was that the approach would allow for faster plutonium disposition. But the reality has been quite the opposite. The program is behind schedule, with no clear, realistic timeline for full disposition. Regulatory approvals, bottlenecks at WIPP, and operational hurdles have made it clear: the current path will take decades, with the taxpayer financial burden likely to increase many times over.

Advanced reactor development, meanwhile, is already progressing. Companies such as TerraPower, Oklo, and X-energy are building initial units within the decade. A coordinated program with these and other developers to convert surplus plutonium into advanced reactor fuel would eliminate the material through fission, not burial. Every atom split in a reactor is an atom permanently removed from the weapons cycle. That’s real, irreversible disposition.

Strengthening Non-proliferation

Critics of plutonium fuel use often raise proliferation concerns. In practice, however, splitting plutonium in fission reactors is the most effective way to ensure it can never be used in a nuclear warhead. Once it’s gone, it’s gone.

The dilute and dispose method, while technically rendering the plutonium less accessible, and does not eliminate it. It still exists, stored underground, with a chemical signature that could, in theory, be recovered by future actors with the means and motive. By contrast, reactor use transforms the material at the atomic level. It is the true gold standard of disposition. The National Academy of Sciences and leading non-proliferation experts have long supported this approach for that reason.

Moreover, fuel fabrication and reactor deployment occur under significant regulatory oversight. If repurposed into the advanced reactor fuel cycle, the U.S. government would dilute plutonium prior to releasing it, and the entire fuel cycle would be subject to strict safeguards. In a time when America is working to establish norms for responsible nuclear development globally, demonstrating the peaceful, productive use of surplus plutonium sets a powerful example and precedent.

Solving Fuel Shortages

One of the most significant bottlenecks to the deployment of advanced nuclear power plants is fuel availability. This is a solvable challenge, and the solution is staggeringly simple.

The thirty-four metric tons of surplus plutonium currently slated for disposal could instead be used to fuel dozens of advanced reactors. It has enough energy potential to power millions of homes and dramatically accelerate the rollout of new, clean power. Harnessing this material would not only relieve the nuclear fuel bottleneck but also serve as a catalyst for new reactor orders, giving U.S. fuel suppliers the demand signal they need to rebuild and scale production. Currently, fuel shortages are slowing reactor development, and the slow pace of reactor development is slowing fuel production. America’s surplus plutonium can break this logjam.

Fuel scarcity doesn’t have to mean delays. Instead, we can turn our excess plutonium into an engine of growth—fueling clean energy, revitalizing U.S. supply chains, and paving the way for cost efficiencies across the board.

A Bipartisan Opportunity

Support for nuclear energy and non-proliferation transcends party lines. Democrats overwhelmingly embrace nuclear power as part of the clean energy transition. Republicans back nuclear power for its strategic and economic value. Converting surplus plutonium into advanced reactor fuel speaks to both constituencies: it reduces waste, promotes innovation, and safeguards the future.

Instead of pouring billions of dollars into burying a valuable resource, we can invest those funds in American industry and energy leadership. We can then use that valuable resource to power communities, reduce emissions, and clean up the legacy of the Cold War—all at once.

Time for Smarter Policy

The dilute and dispose program was born from a specific time and set of constraints. But circumstances have changed. Advanced nuclear technology is on the rise. America’s energy security urgently demands scalable, clean power. Our leadership in artificial intelligence is at stake. And the public demands fiscal responsibility and real results.

It’s time to end the dilute and dispose program and infuse that effort into a bold, new strategy: safely repurposing this surplus plutonium as fuel for American prosperity. This path offers speed, security, sustainability, and savings. It is a rare win-win in public policy. Let’s not bury that opportunity. Let’s use it to power our future.