DOE Taps Five Nuclear Startups to Turn Cold War Plutonium into Energy
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A Cold War Legacy Becomes a Startup Resource
For decades, the United States government has managed a persistent and hazardous byproduct of its Cold War nuclear ambitions: roughly 100 tons of plutonium. Originally synthesized for high-yield atomic weaponry, this material became a strategic and environmental liability as nuclear stockpiles were dismantled, leaving the Department of Energy (DOE) to maintain high-security storage facilities for a substance with a half-life of 24,000 years.
In a pivot toward utilizing this waste for energy production, the Department of Energy announced Tuesday that it has selected five nuclear startups to enter advanced negotiations to acquire portions of the government’s plutonium stockpile. The DOE has previously earmarked 34 tons of this material specifically for disposal; the administration now views the private sector as a viable path to neutralizing the material while jumpstarting the next generation of nuclear power.
The cohort of selected companies includes Oklo, Standard Nuclear, Shine Technologies, Flibe Energy, and Exodys Energy. These firms are exploring diverse reactor designs that can consume isotopes that traditional light-water reactors cannot.
The Technical Pivot to MOX and Fast Reactors
The primary challenge in using plutonium is its volatility and the precision required to integrate it into a fuel cycle. Several of the selected firms are betting on Mixed Oxide (MOX) fuel—a blend of plutonium and uranium. While France has successfully operationalized MOX production, U.S. efforts to establish a domestic facility in South Carolina were abandoned during the first Trump administration due to catastrophic budget overruns and timeline slippages.
Current strategies among the selected startups vary by design. Oklo is developing a fast reactor capable of running on both traditional uranium and plutonium, which would allow the company to fuel its initial deployments with government-sourced materials. Exodys Energy is similarly focused on MOX fuel integration, while Flibe Energy is pursuing a molten salt approach intended to run on plutonium and other fission by-products.
The geopolitical dimension of this fuel cycle is further complicated by international partnerships. Newcleo, a U.K.-based firm and partner to Oklo, has indicated intentions to build its own MOX fabrication facility, potentially bridging the gap where U.S. domestic infrastructure failed.
Political Ties and Security Risks
The intersection of government policy and private venture capital is particularly tight in this initiative. Energy Secretary Chris Wright previously served on Oklo’s board before joining the administration. While Wright has stated he divested his shares upon taking office, the optics of a cabinet member overseeing the distribution of radioactive material to a former employer are noteworthy. Oklo also maintains a high-profile connection to OpenAI’s Sam Altman, who served as the board chair following the company’s merger with his acquisition vehicle, AltC, before resigning last year.
However, the plan has met with skepticism from nuclear non-proliferation experts. The core of the debate rests on whether moving weapons-grade material from centralized government vaults to private startup facilities increases the risk of theft or accident.
“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,” says Scott Roecker, Vice President at the Nuclear Threat Initiative.
For the DOE, the gamble is that the urgency of the energy transition and the need to clear toxic stockpiles outweigh the security risks. The five startups must now navigate a rigorous series of negotiations regarding the transportation and safeguarding of the plutonium before a single gram moves from government custody.
