Army awards $2.2 billion to five firms for

The US Army has selected five companies to advance nuclear microreactor prototypes, allocating up to $2.2 billion for development and testing. The service aims to deploy more than 20 microreactors on its installations, with the first operational target set for the end of September 2028.

Jeff Waksman, the principal deputy assistant secretary of the Army for installations, energy and environment, announced the Janus program awards. He told reporters that a vulnerable domestic electric grid and potential difficulties in moving fossil fuels make nuclear energy a strategic necessity. "That makes nuclear energy just a natural game changer for the Army," Waksman said, according to Breaking Defense. "It makes sense for the Army to take the lead here."

Selected Companies and Bases

Five firms have received Other Transaction Authority agreements to continue their microreactor designs. Each is paired with a specific Army installation for potential deployment.

Waksman cautioned that this list could be shortened further. All five companies are still developing their designs and raising capital. The $2.2 billion in government funds, to be spent between fiscal 2027 and 2031, is intended to cover prototype design, construction, and the first year of operations. Radiant disclosed it could receive up to $750 million to develop and deploy 15 of its Kaleidos microreactors.

However, Waksman stated that government funding will only provide a fraction of the required capital. "We are expecting that the majority of the money coming into these reactor programs will be private capital, not government," he said.

The agreements contain flexible contractual milestones. "So if a company is not performing, if they are just disappointing, not delivering what we’re expecting, we can pull future milestones," Waksman explained. "There are no termination fees."

Development Pathways and Fuel

The push follows a May 2025 executive order from President Donald Trump directing the Army to lead a Pentagon nuclear reactor effort. The service later worked with the Defense Innovation Unit on the Janus program, identifying nine possible sites last November.

"This was an extraordinarily rigorous competition to determine which companies really have the best possibility to build commercial nuclear microreactors," Waksman said. He tempered expectations for 2028, noting, "We don’t expect all five of these companies are going to turn on a reactor in 2028. In fact, they definitely will not."

Each company is pursuing a distinct technical path. Radiant's Chief Nuclear Officer Rita Baranwal told Breaking Defense that its design uses fuel made to its specifications. The Department of Energy provided Radiant with 19.75 percent high-assay, low-enriched uranium (HALEU). Its fabricator, Standard Nuclear, then produces Tristructural Isotropic (TRISO) fuel particles from that feedstock.

Similarly, an Antares official stated earlier this summer that it is also using 19.75 percent HALEU, with BWXT fabricating its TRISO fuel particles. General Atomics’s Tactical Energy System is fueled by uranium zirconium hydride.

This nuclear initiative coincides with a broader reassessment of the Army's energy plans. Waksman recently announced the scrapping of a 2024 memorandum of understanding with the Tennessee Valley Authority for green energy at Redstone Arsenal and Fort Campbell. He indicated that increased use of natural gas is the most likely short-term solution for those locations, citing its cheap and plentiful supply, though pipeline logistics and local supply concerns must be resolved.