Ford reported in late November 2025 that the U.S. Department of Defense (DOD) is accelerating the development of microreactors for military use, a push that developers say could lift the entire advanced nuclear sector.
Image: REUTERS/Kiryat Gat
The U.S. Army launched the Janus Program on October 14 to install a small modular reactor (SMR) on a military base by 2028 in the latest Department of Defense (DOD) push to promote the technology. The program aims to provide off-grid power for military installations, communication networks, weapons systems and command nodes. Janus was born out of four executive orders signed by President Trump in May to accelerate nuclear deployment. One of them directed the Department of Energy (DOE) to develop three pilot reactors by July 2026, while another instructed the DOD to build a reactor on a military installation by September 2028.
While many of the companies selected for DOE’s program aim to build reactors of between 20 MW and 75 MW, the DOD is focusing on microreactors, which feature capacities of between 1 MW and 20 MW and are designed to be fully transportable. The DOD’s first effort to promote SMRs as a military solution was Project Pele, which was launched in 2019 to provide 24/7 electricity for military operations in remote and challenging environments. BWXT Advanced Technologies started building a 1.5 MW mobile reactor under the project at Idaho National Laboratory in September 2024.
The DOD’s latest SMR program, Project Janus, is part of the Advanced Nuclear Power for Installations (ANPI) program, announced jointly in April 2024 by the Defense Innovation Unit (DIU), Army and Air Force to develop microreactors on military sites.
US operational nuclear power plants as of February 2025 Source: U.S.
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The DOD is expected to issue a Request for Proposals “in a few weeks” to select the companies that will take part in the Janus program, law firm Pillsbury said in a report on October 21.
Chosen companies will build their reactors at specific army installations, with Janus providing uranium fuel cycle and broader supply chain support, said Stephen Comello, Senior Vice President, Strategic Initiatives at the EFI Foundation, a non-profit organisation focused on the energy transition. While DOE awardees are responsible for all costs and activities relating to site identification, fuel supply, reactor development and spent fuel storage, those involved in the Janus program will benefit from some level of federal funding and allocated military sites, Comello said. DOE laboratory teams that contributed to “the technical, policy and legal aspects of Project Pele are expected to collaborate again with the Army as the Janus initiative moves forward,” Pillsbury said.
In October, Radiant Industries signed the first agreement to develop a microreactor on a U.S. military base as part of the ANPI program and a separate deal to build a microreactor factory on the Manhattan Project site in Oak Ridge, Tennessee, that would start producing the company’s 1 MW Kaleidos microreactor in 2028, with the goal of eventually manufacturing 50 units a year.
Seven other companies are also eligible for the ANPI program: Antares Nuclear, BWXT, General Atomics Electromagnetic Systems, Kairos Power, Oklo, Westinghouse and X-Energy. Radiant and Oklo are participating in both the DOD and DOE programs.
DOE, DOD synergies
The DOD’s microreactor initiative is “a demand signal for resilient, clean power and it is complementary to DOE’s work, which is good for the whole advanced reactor industry,” said Bonita Chester, Oklo Head of Communications and Media. It can help “standardize components, strengthen fuel and manufacturing supply chains, and grow the specialized workforce,” she told Reuters Events.
There could be synergies between the DOE and DOD initiatives. For instance, Antares is working with the DOE to license its prototype reactor, while the DOD could be a transition pathway from prototypes to future commercial units, where the Nuclear Regulatory Commission (NRC) would have pre-existing familiarity with its technology, Jordan Bramble, the CEO of developer Antares Nuclear, told Reuters Events.
An X-energy spokesperson said the company fully supports “the intent of recent DOE programs aimed at advancing commercial microreactor development” but had prioritised its relations with the DOD as the best conduit for progressing its Xenith microreactor.
“We believe that the [Defense] Department’s efforts provide a clear path to deployment, one that supports both military and commercial applications,” the spokesperson told Reuters Events.
Small modular reactor projects by country Source: International Energy Agency
report 'Electricity 2024: Analysis and Forecast to 2026.'
Faster project safety reviews are not guaranteed simply because of DOD involvement but “Janus program applicants may see efficiencies garnered from interagency agreements, coordination, and information sharing between the NRC, DOE and DOD,” Comello told Reuters Events.
Moreover, DOD regulations limit environmental assessment reviews to a maximum of one year, with no more than two years for environmental impact statements. By comparison, the NRC took 41 months to complete a design review for NuScale, the only SMR developer to have secured an NRC licence to date. NuScale says that it set “a record as the fastest design review in the NRC’s history.”
Commercial deployment
This initiative will almost certainly help companies like Antares “bridge the gap between prototype reactors and commercially viable performance, capacity factors and economics,” Bramble said. Follow-on commercial sector customers are likely to be “extractive industries, industrial power and heat, remote communities, state and municipal critical infrastructure, data centers, utilities, and potentially U.S. allies,” he added.
X-energy said it plans to advance its 3 to 10 MW Xenith microreactor for both the military and commercial markets and so intends to pursue regulatory approval from the NRC in parallel to its work through ANPI. Apart from the military, it aims to deploy its reactors at ports, hospitals, logistics hubs and water treatment facilities. The company applied for a construction permit to build its first reactor at the Long Mott plant in Calhoun County, Texas, in March 2025, with the aim of completing it in the early 2030s.
DOD initiatives may produce restricted configurations for defense missions but “derivative commercial versions" of the same core technology can be developed concurrently for the civilian market under NRC regulation, said the X-energy spokesperson. Any microreactor intended for commercial operation would still be subject to the NRC’s licensing process, they added.
Download our exclusive report on accelerated US SMR prototypes (here).
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