The United States Army has mobilized up to $2.2 billion for Janus, an ambitious five year campaign to build and operate more than 20 commercial nuclear microreactors at military installations.
The program seeks to move advanced reactors beyond federal demonstrations and deliver useful electricity from at least one unit by Sept. 30, 2028.
Five developers received initial assignments covering major Army posts.
Antares Nuclear was selected for Fort Bragg, BWXT Advanced Technologies for Fort Campbell, General Atomics Electromagnetic Systems for Fort Hood, Radiant Industries for Fort Benning, and Westinghouse Government Services for Fort Drum.
Radiant disclosed the largest agreement, valued at up to $750 million. The company plans to deliver 15 factory built Kaleidos microreactors by 2030, each rated at 1 MWe, beginning with three units at Fort Benning.
Antares also intends to deploy reactors in groups of three, starting with its R1 design at Fort Bragg.
Each sodium heat pipe unit is expected to produce between 100 kWe and 1 MWe, using TRISO particle fuel supported by testing at Idaho National Laboratory.
BWXT is pursuing a substantially larger plant for Fort Campbell. Its proposed 20 MWe BWXT Advanced Nuclear Reactor uses nitrogen coolant and uranium oxycarbide TRISO fuel, with construction targeted for late 2028 and operation anticipated during the early 2030s.
General Atomics will advance its Tactical Energy System through development, testing, and site planning at Fort Hood.
The liquid metal cooled reactor has a baseline net output near 5 MWe and an architecture that can scale to approximately 20 MWe.
Westinghouse plans to deploy its eVinci heat pipe microreactor at Fort Drum, although output, contract value, and schedule details remain undisclosed. The reference design is intended to operate for eight years or longer before refueling.
The companies will own, construct, and operate the reactors through fixed price, milestone based agreements managed with the Pentagon innovation unit DIU.
Payments will be released only after developers complete defined technical, regulatory, manufacturing, and hardware objectives.
Army officials deliberately modeled the structure on NASA efforts that helped commercial space companies cross the difficult gap between prototypes and dependable services.
Dr. Jeff Waksman, principal deputy assistant secretary of the Army for Installations, Energy and Environment, emphasized the importance of physical engineering achievements.
“Hardware is rock solid. If they are making hardware progress, that means that they are making real progress.”
The Army can withdraw future milestones from companies that fall behind and redirect funding toward stronger performers or potential new participants.
Because future work is not obligated in advance and carries no termination fees, Janus gives the government unusual flexibility to manage technical and financial risk.
“We do not expect all five of these companies to turn on a reactor in 2028.
In fact, they definitely will not,” Waksman said. The portfolio is instead designed to provide several credible pathways toward getting at least one reactor into sustained service by the presidential deadline.
Janus reactors will receive authorization through the Army Reactor Regulatory Office rather than the Nuclear Regulatory Commission because the units will serve defense installations.
The Army is coordinating with the Energy Department and federal nuclear regulators so technical evidence gathered under military oversight can support later commercial licensing.
The selected reactors cannot use highly enriched uranium, and every design relies on encapsulated fuel.
The Army also requires passive safety characteristics that allow reactors to shut down without offsite electricity, diesel powered emergency cooling, or other active support systems.
Fuel qualification and manufacturing readiness were decisive selection factors. Most Janus designs use TRISO fuel, while the General Atomics concept employs encapsulated uranium zirconium hydride fuel derived from the company’s long experience with TRIGA research reactors.
Waste handling requirements are equally strict. All radioactive material must leave an Army installation within two years after a Janus reactor shuts down, and the service expects to negotiate a common arrangement for the Energy Department to receive spent fuel.
The reactors will supplement local utility systems rather than replace them.
They are intended to remain connected to installation grids during normal conditions, then supply resilient electricity to critical military infrastructure when outside power fails.
Utilities will therefore play important roles in interconnection studies, operating coordination, and site planning.
At Fort Drum, interest from the New York Power Authority helped support alignment between the installation and the Westinghouse eVinci project.
Janus also depends heavily on private capital, since the Army expects commercial financing to represent most total investment.
Government milestone payments are intended to absorb part of the exceptional cost and uncertainty surrounding the first few reactors, not permanently subsidize uncompetitive businesses.
“What we’re trying to transition is from experiments and prototypes to actual commercial products. That is the transition that we are trying to effect here.”
The true economics will remain uncertain until developers build multiple units and spread engineering, factory, fuel, and licensing expenses across a wider fleet.
Success will be measured not by brief criticality experiments, but by reactors delivering useful, reliable electricity and becoming repeatable products for military and civilian customers.
