DOE Pivots to Fueling Advanced Reactors with Weapons-Grade Plutonium
In late May 2026, the U.S. Department of Energy (DOE) selected five advanced nuclear companies to begin advanced negotiations under the Surplus Plutonium Utilization Program (SPUP). This federal initiative, which aligns with President Trump's Executive Order 14302 ("Reinvigorating the Nuclear Base"), halts the previous "dilute and dispose" strategy in favor of converting weapons-grade plutonium into advanced reactor fuels.
The five selected companies entering advanced negotiations are:
- Oklo Inc. (NYSE: OKLO)
- Flibe Energy
- Exodys Energy
- SHINE Technologies
- Standard Nuclear
The program aims to dispose of a portion of the 34 metric tons of surplus plutonium previously designated for cleanup by making up to 20 metric tons (4.4 MT metal and 15.3 MT oxides) of DOE-owned plutonium available for "recycling, processing, and manufacturing" into commercial nuclear fuel.
SMR Developer Strategies & Market Reaction
For pre-revenue microreactor developers, the availability of surplus weapons material offers a critical bridge fuel, bypassing the current domestic bottlenecks in High-Assay Low-Enriched Uranium (HALEU) enrichment infrastructure.
- Oklo (NYSE: OKLO): Oklo announced it will partner with European advanced reactor and MOX fuel developer Newcleo on the program. This builds on their October 2025 strategic partnership to develop a $1.68 billion advanced fuel center in Oak Ridge, Tennessee. Following the announcement, Bank of America reinstated coverage on Oklo with a "Buy" rating and an $80 price target, citing its vertically integrated model. As of June 1, 2026, Oklo maintains an $11.64 billion market capitalization with $1.59 billion in cash, despite running a $50.7 million free cash flow deficit for the quarter ending March 31, 2026.
- Flibe Energy: The Alabama-based startup plans to utilize the surplus plutonium for its lithium fluoride thorium reactor (LFTR) technology, complementing its ongoing studies on electrochemical methods to reprocess spent nuclear fuel.
Political and Environmental Backstory
The shift has sparked intense political debate. Proponents like the American Nuclear Society (ANS) endorse the move, noting that recycling weapons material helps alleviate fuel cost and supply constraints. However, congressional Democrats have raised proliferation alarms. In a September 2025 letter to the administration, Sen. Edward Markey (D., Mass.) and Reps. John Garamendi (D., Calif.) and Donald Beyer (D., Va.) argued that transferring weapons-grade plutonium to private startups "raises serious weapons proliferation concerns, makes little economic sense, and may adversely affect the nation’s defense posture."
Representative Quotes
"Fuel supply constraints are a key throttle to advanced reactor development. This program creates a pathway to use existing surplus material as bridge fuel for advanced reactors to bring more reactors on line sooner. Material that has been set aside for disposal can instead be converted into fuel to produce electricity through fission."
— Jacob DeWitte, CEO of Oklo, quoted in ANS Nuclear Newswire
"The program follows President Trump’s Executive Order 14302, 'Reinvigorating the Nuclear Base,' which ordered the DOE to halt its Biden-era 'dilute and dispose program' and to '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.'"
— ANS Nuclear Newswire