The US Department of the Air Force (DAF), in conjunction with the Defense Innovation Unit (DIU), has selected three companies to potentially develop and operate a microreactor on a DAF installation, as part of the Advanced Nuclear Power for Installations (ANPI) initiative.
Earlier in April, DAF named Buckley Space Force Base, Colorado, and Malmstrom Air Force Base, Montana, as the first two sites chosen for the ANPI initiative. The Joint Base San Antonio, Texas, has now been added as the third potential location to site to host a nuclear microreactor.
Eight competitors were selected in 2025 for ANPI as eligible for funding. The Air Force has now picked three companies from that vendor pool to proceed with design work for its installations: Antares Nuclear, Radiant Industries and Westinghouse Government Services. (The Army has its own parallel nuclear microreactor project, and was part of the larger vendor pool – the other companies were BWXT Advanced Technologies, General Atomics Electromagnetic Systems, Kairos Power Oklo, and X-Energy).
The Air Force press release says Antares would be paired with Joint Base San Antonio in Texas; Radiant with Buckley Space Force Base in Colorado; and Westinghouse with Malmstrom Air Force Base in Montana, which also hosts a nuclear missile fleet.
“The future of air and space dominance is powered by resilient energy,” said Michael Borders, Assistant Secretary of the Air Force for Energy, Installations and Environment. “By integrating advanced nuclear technology, we are not just keeping the lights on; we are guaranteeing that our most critical national security missions will never be held at risk by a power outage. This is a pivotal moment for the Department of the Air Force.”
The Air Force is separately running a pilot programme to demonstrate nuclear microreactor technology at Eielson Air Force Base in Alaska. The service announced last year that it intended to partner with Oklo for that project. This is a stand-alone effort focused on demonstrating the feasibility and operational benefits of a microreactor at a single installation.
The ANPI initiative seeks to have at least one advanced nuclear reactor operating on at least one Air Force installation by 2030. The next steps will include siting and environmental analyses as part of the National Environmental Policy Act process. All three selected firms are developing advanced micro reactors that use high-assay low-enriched uranium (HALEU) tri-structural isotropic (TRISO) fuel and have reactor outlet temperatures of between 650 and 750 degrees C.
Radiant’s Kaleidos design is a helium-cooled high-temperature gas-cooled reactor (HTGR) with an outlet temperature of 750 degrees C, which is suitable for both electricity and industrial process heat. Once deployed, each Kaleidos unit will be capable of supplying 1.2 MWe of electricity over five years to support critical operations in remote locations. A testing programme to advance development of the reactor design is expected to begin at the Idaho National Laboratory’s DOME test facility. Radiant says the first Kaleidos reactors will be delivered by 2028.
“Together with our incredible government partners, Radiant is making the nuclear renaissance a reality,” said Radiant Chief Revenue Officer Mike Starrett. “The American energy industry needs to make progress now, not in 5 or 10 years. With a full-power reactor already under assembly, Radiant will deliver.”
Westinghouse’s eVinci microreactor design uses alkali metal heat pipes to transfer heat passively from the core to an open-air Brayton cycle. This operates at near-atmospheric pressure eliminating the need for reactor coolant pumps and high-pressure vessels. eVinci can produce 5 MWe with a 15 MWt core design that can run for eight or more years before refuelling.
The Antares R1 cooled microreactor is designed primarily for rapid deployment and strategic infrastructure. It uses sodium heat pipes and a nitrogen Brayton cycle. Its outlet temperature is optimised for high-efficiency power conversion in a very small footprint. Antares says it expects to conduct a reactor demonstration in 2026 and test its first electricity-producing reactor in 2027, with initial production deployments beginning in 2028. The company is in the final phase of the Department of Energy (DOE) Reactor Pilot Program to build a reactor that achieves criticality before 4 July. BWX Technologies began fabrication of the TRISO fuel for the company’s initial reactors in 2025.
Antares CEO and founder Jordan Bramble said the company is “grateful and proud” to partner with Joint Base San Antonio, the DAF and the Defense Innovation Unit: “We built this company to deliver resilient power for missions like this,” he said.
Westinghouse’s eVinci is also a heat pipe-cooled microreactor, which can produce up to 5 MWe with a 15 MWt core design, running for eight or more full-power years before refuelling. The technology is designed to be factory-built and assembled before it is shipped. Westinghouse Government Services President Rich Rademacher said the eVinci microreactor “is perfectly suited to ensure our Armed Forces have the reliable and resilient energy they need for mission-critical operations globally”.
Neutron Bytes questioned whether any of these microreactors will meet the military needs for reliable power. “As there are, as yet, no formal contracts for any of these deals, costs are unknown. Any action to proceed with a contract between any of these developers and the military is contingent on any of these microreactors getting an NRC licence. Then and only then will the financial terms come into play.”
It noted that a lot of federal government activity related to promoting nuclear energy “is, absent actual funding, aspirational driven by the four nuclear energy executive orders issued by the administration”.
Then there is the question of “how to prove that any of these micro units can provide 24×7 365/days/year for up to a decade or more – a military base commander, who has a focus on power to assure tactical readiness, needs ironclad certainty about that power”. According to Neutron Bytes: “The ‘move fast and break things’ mentality of some startups is not going to cut it when it comes time for meeting the Air Force needs for power. Each of these microreactor developers have a lot of work ahead to prove that they can do what the military needs them to do.”
