The US Department of Energy (DOE) has selected five companies to enter advanced talks over potentially using its Cold War-era plutonium as a nuclear reactor fuel. DOE named these as Oklo, Exodys Energy, SHINE Technologies, Standard Nuclear and Flibe Energy.
The Surplus Plutonium Utilization Program, established in October 2025, is a federal initiative managed by DOE designed to recycle legacy weapons-grade plutonium into commercial fuel for next-generation advanced nuclear reactors. Following its establishment, DOE issued a “request for applications” opening opened the door for private developers to propose recycling and processing plans for roughly 20 tonnes of surplus material.
The programme was established in line with Executive Orders (EOs) signed by President Donald Trump in May 2025. EO 14299 Deploying Advanced Nuclear Reactor Technologies for National Security ordered the halt of the prior “dilute and dispose” programme and initiated the shift toward commercial availability. EO 14302 Reinvigorating the Nuclear Industrial Base directed the Secretary of Energy to unlock the surplus plutonium stockpile specifically for private industry fabrication into advanced reactor fuel.
The US holds roughly 19.7 tonnes of surplus plutonium stored at high-security weapons facilities in South Carolina, Texas, and New Mexico, relics from dismantled nuclear warheads that carry a 24,000-year half-life. Companies building advanced small modular reactors (SMRs) are constrained by a lack of domestic uranium enrichment infrastructure. Plutonium has been proposed as an excellent alternative “bridge fuel” to get these reactors online sooner.
“The Surplus Plutonium Utilization Program is anticipated to help companies unlock the next level of private funding to broaden domestic nuclear fuel supplies, spur innovation on American recycling technologies, and unlock private sector funding to fuel the nation’s nuclear renaissance,” a spokesperson for DOE’s Office of Nuclear Energy said.
Oklo and Flibe Energy were the only companies to directly comment on DOE’s selection. Oklo said it would lead the utilisation of surplus plutonium in partnership with European nuclear start-up newcleo, which would “bring relevant fuel experience and potential project capital, subject to definitive agreements, customary approvals, and applicable US security and safeguards requirements.
“This programme creates a pathway to use existing surplus material as bridge fuel for advanced reactors to bring more reactors online sooner,” said Oklo cofounder and CEO Jacob DeWitte. “Material that has been set aside for disposal can instead be converted into fuel to produce electricity.” Stefano Buono, newcleo CEO and founder, said using the plutonium as fuel would reduce US nuclear liabilities.
In October 2025, Oklo announced a strategic partnership with newcleo to develop advanced fuel fabrication infrastructure in the US, including potential work related to surplus plutonium. The partnership includes an investment of up to $2bn, subject to mutually acceptable documentation and industry conditions, via a newcleo-affiliated vehicle for such a project.
In February 2026, newcleo initiated its pre-application engagement with the US Nuclear Regulatory Commission (NRC) for both an advanced fuel fabrication facility and a lead-cooled fast reactor design to support the future deployment of its fuel fabrication and reactor facilities in the US market.
Flibe Energy Inc (FEI) said its selection follows an earlier DOE award for used nuclear fuel recycling research for which it was selected for negotiation earlier this year. “The two efforts are complementary: together they give the United States more options for realising the energy value of materials that are presently outside of commercial use.”
FEI CEO Kirk Sorensen noted: “The available plutonium is an ideal fuel for FEI’s molten salt reactor options, sustaining them and unlocking extended operations. This opportunity aligns with our focus on utilising materials in spent nuclear fuel to sustain future reactors. The programme will help unlock new advancements in modern nuclear power technology and provide a real benefit to the citizens of the United States.”
While Standard Nuclear did not comment directly on its selection, in December 2025 it published a paper: Transforming Liability into Opportunity: Plutonium & Transuranic Streams.
In noted: “The US government currently allocates billions of dollars to the Dilute and Dispose programme essentially taking weapons-grade plutonium (a highly refined, energetic fuel), mixing it with adulterants, and burying it in salt caverns…. This represents a profound economic paradox: the taxpayer is paying to destroy a resource they have already paid to produce. The new policy landscape recognises that this material is ‘shovel-ready’ fuel. By converting this plutonium into TRISO or metal fuel, the DOE can reduce disposal costs while simultaneously jumpstarting the advanced reactor fuel supply chain.”
It described how transuranic (TRU) could be processed using TRISO (Tri-structural Isotropic) particle fuel, noting that irradiation of Pu-bearing TRISO had been previously demonstrated on numerous occasions. “In this concept, TRUs are encapsulated in TRISO particles and irradiated in High-Temperature Gas Reactors (HTGRs) or existing Light Water Reactors.” The reactor “burns” the TRUs, generating electricity. “The process destroys the vast majority of the transuranic content, significantly lowering the radiotoxicity of the remaining material.… The discharged spent fuel is already in a TRISO form – a silicon carbide ‘pressure vessel’ that is essentially geological-repository ready. It is corrosion resistant and leach-resistant, serving as an ideal final waste form without complex post-processing.”
Meanwhile, DOE’s National Nuclear Security Administration (NNSA) made available on its website, the final Supplemental Environmental Impact Statement (SEIS) and Amended Record of Decision (AROD), for Enhanced Plutonium Facility Utilisation at Lawrence Livermore National Laboratory (LLNL).
The decision elevates the LLNL Plutonium Facility from a Security Category III to a Security Category II rating, restoring high-security processing capabilities that were phased out over a decade ago. This change permits the laboratory to dramatically scale up the volume of fissile nuclear materials handled on-site. The authorisation codifies a projected 180% annual increase in plutonium shipments entering and exiting the Livermore facility. The ultimate objective is to provide the required material infrastructure to conduct advanced physics research and engineering necessary to maintain and modernise the U.S. nuclear weapons stockpile.
