The United States government is sitting on a Cold War inheritance that nobody quite knows what to do with. The Energy Department holds more than 50 tons of surplus plutonium left over from nuclear weapons programs, material the agency had previously been planning to dilute and bury underground. That plan, years in the making and broadly supported by nonproliferation experts, has now been set aside. In its place, the Trump administration has unveiled a new idea: hand the plutonium to private companies, and let them turn it into fuel.
On Tuesday, the Department of Energy announced it had selected five companies to enter into advanced negotiations to potentially receive portions of the surplus stockpile under its Surplus Plutonium Utilization Program, which was established last year. If finalized, it would mark the first time the US government has made weapons-grade plutonium available to private companies.
The five companies selected are Oklo, Standard Nuclear, Exodys Energy, SHINE Technologies, and Flibe Energy. Each brings a different reactor design and a different vision for what to do with the most dangerous material the Cold War left behind. What they share is an argument that the nuclear energy renaissance now gathering momentum in America cannot happen fast enough without a fuel supply that does not yet fully exist, and that a 50-ton stockpile of weapons-grade plutonium is the fastest bridge to building it.
The Fuel Shortage Nobody Is Talking About
To understand why the Trump administration is moving in this direction, it helps to understand the nature of the problem it is trying to solve. Energy firms want to build a new wave of nuclear reactors, but the United States cannot yet make enough conventional fuel from uranium to supply the plants. Harvesting old plutonium stockpiles, the argument goes, could provide a short-term fix.
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“A lack of fuel is one of the biggest choke points in expanding nuclear power right now,” said Jacob DeWitte, the CEO of Oklo, which is developing a novel type of small reactor intended to run on plutonium. Oklo, a California-based nuclear energy startup that has become one of the most prominent companies in the advanced reactor space, plans to develop the fuel in partnership with Newcleo, a European reactor developer. Newcleo’s CEO Stefano Buono said that using the plutonium as fuel would reduce US nuclear liabilities, and Oklo framed the program as a pathway to use existing surplus material as bridge fuel for advanced reactors to bring more units online sooner.
Three of the five chosen companies have reactor designs built specifically around the material. Oklo is developing a reactor that can run on both conventional uranium fuel and plutonium. Exodys Energy is working on a reactor that uses plutonium as part of mixed oxide fuel, known as MOX, which blends uranium and plutonium. Flibe Energy is pursuing a reactor that would run on plutonium along with other leftovers from the fission process.
The Department of Energy framed the program in expansive terms. Michael Goff, the principal deputy assistant secretary of nuclear energy, said the initiative is anticipated to help companies unlock private funding, broaden domestic nuclear fuel supplies, spur innovation on American recycling technologies, and fuel the nation’s nuclear renaissance. The language is optimistic. The history of similar programs is considerably less so.
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A Graveyard of Failed Attempts
The idea of converting surplus weapons plutonium into MOX fuel for reactors is not new. It has been tried, at significant expense and with very limited success, by multiple governments over several decades.
MOX fuel is currently produced in France, and while the US had plans to make it in South Carolina, the first Trump administration cancelled the project after it blew through budgets and timelines. That South Carolina facility, known as the MOX Fuel Fabrication Facility at the Savannah River Site, absorbed billions of dollars in federal investment over more than a decade before being abandoned. Its cancellation was widely cited by nuclear policy analysts as evidence that the economics of weapons plutonium conversion are deeply unfavorable compared to simply disposing of the material.
Japan attempted its own civilian plutonium program for decades and ultimately accumulated a stockpile of separated plutonium with no clear use and enormous associated security costs. The United Kingdom’s experience with civilian plutonium reprocessing produced similar results: a legacy liability that costs hundreds of millions annually to store and secure, with no commercially viable pathway to utilization in sight.
Scott Roecker, a vice president at the Nuclear Threat Initiative, a nonprofit group dedicated to reducing the spread of nuclear weapons, was direct about what that history means. “Countries have tried this before, and they concluded that, as nice as it would be to use that plutonium as fuel, it’s really just a liability and we need to dispose of it permanently,” he said.
The new cohort of nuclear startups argue that the difference this time is technology. Their reactor designs are built around plutonium-bearing fuel from the ground up, rather than adapted from uranium-based systems. Oklo’s partner Newcleo has stated it intends to build its own MOX fuel fabrication facility to supply the program. Whether that changes the economic calculus remains to be proven at scale.
The Conflict of Interest Question
Before getting to the nonproliferation concerns, there is a personnel question that analysts have flagged and that the administration has not fully addressed.
Energy Secretary Chris Wright once sat on Oklo’s board of directors. He stepped down when he joined the administration and says he sold his shares. Sam Altman chaired Oklo’s board after the company merged with his acquisition vehicle, AltC, and he left that role last year. Oklo is the most prominent of the five selected companies and the one whose stock responded most visibly to the announcement, with shares rising more than 5.5 percent to $69.51 on the day of the Energy Department’s announcement.
The Energy Department has stated that Wright recused himself from decisions involving Oklo. Critics have questioned whether that recusal is sufficient given the depth of his prior relationship with the company’s leadership and the significance of the program’s potential financial benefit to Oklo shareholders.
The Nonproliferation Problem
The most serious objections to this program come not from financial watchdogs but from the community of experts who have spent their careers thinking about how nuclear weapons spread and how to prevent that from happening.
The proposal has immediately drawn scrutiny from nonproliferation experts, who warn that weapons-grade plutonium brings serious security and safeguards risks if it is moved from a disposal pathway into a civilian fuel cycle.
The concern is structural. Weapons-grade plutonium is not merely a hazardous material that requires careful handling. It is, in the precise technical sense, bomb-making material. A sphere of plutonium roughly the size of a softball is sufficient to construct a nuclear device capable of destroying a city. The material the Energy Department is proposing to transfer to private companies is the same material that once sat inside nuclear warheads pointed at the Soviet Union.
A letter sent to President Trump from a group of concerned experts made this arithmetic explicit: 20 metric tons of weapons-usable plutonium represents enough material for approximately 2,000 nuclear bombs. The letter argued that such a transfer goes against long-standing, bipartisan US nuclear security policy and raises serious weapons proliferation concerns, noting that for five decades the United States avoided the commercial use of plutonium and opposed the spread of reprocessing technology specifically to prevent nations or non-state actors from obtaining weapons-usable material.
The concern is not that Oklo or Flibe Energy are planning to build nuclear weapons. The concern is about what happens across the long and complex supply chain that would need to exist between a federal weapons storage facility in South Carolina, Texas, or New Mexico and a private reactor operator’s fuel fabrication and handling infrastructure. The plan is not yet final, and companies will still have to negotiate with the federal government over how to secure and transfer the plutonium. Those negotiations will determine whether the security architecture around this material is adequate. They have not yet produced any public agreement on what that architecture will look like.
Transportation of weapons-grade plutonium through the civilian supply chain introduces new physical security requirements at every node. Fabrication facilities that process the material into MOX fuel create new sites where the material must be secured against theft or diversion. Private companies, unlike federal weapons laboratories, operate within a commercial context that creates different incentive structures around cost management, including the costs of physical security. Every cost-cutting decision in a private company’s supply chain that touches this material is a potential gap.
What Comes Next
The program is not final. Each of the five selected companies must still negotiate the specific terms under which they would receive the material, including how it would be secured during transport, fabrication, and storage. Those negotiations will be conducted under close scrutiny from congressional critics, nonproliferation watchdogs, and international partners who have their own concerns about how US plutonium management policy evolves.
Supporters see a chance to help advanced reactors secure fuel and to convert a long-standing nuclear security burden into a usable energy asset. Whether the program becomes a breakthrough or another expensive detour will depend on whether the technology can prove it can handle the material safely, at scale, and within the strict rules that surround plutonium.
The nuclear energy sector is at an inflection point. Demand for carbon-free baseload power is rising faster than any other time in recent history, driven by data center growth, AI infrastructure build-out, and the electrification of transportation and industry. The case for expanding nuclear energy’s role in that transition is compelling and enjoys rare bipartisan support in Washington. The fuel supply constraint that Oklo and its peers describe is real.
But the material at the center of this program is not an ordinary industrial input. It is the most tightly controlled substance on earth, for reasons that have nothing to do with energy policy and everything to do with the geometry of nuclear annihilation. The Trump administration is betting that American startup ingenuity can solve a problem that France, Japan, and the United Kingdom could not. If the bet pays off, it reshapes the nuclear fuel supply chain for a generation. If the security architecture fails anywhere along the way, the conversation shifts from energy policy to catastrophe response.
Those are the stakes. The negotiations are just beginning.
