The Department of the Air Force announced on Wednesday that Joint Base San Antonio (JBSA) in Texas has been selected as the third site for a pilot program testing micro nuclear reactors on military installations. 

“The service announced on April 8 that Buckley Space Force Base, Colorado, and Malmstrom Air Force Base, Montana, were the first two sites chosen for the ANPI initiative,” said the Department of the Air Force.

The program is designed to provide military bases with an independent and reliable power source to ensure that national security missions remain operational regardless of the status of the commercial power grid.

“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,” added Michael Borders, assistant secretary of the Air Force for Energy, Installations, and Environment.

The Air Force has selected Antares Nuclear, a company based in California, to potentially develop and operate these reactors at JBSA. 

Designed for use in various environments

Micro nuclear reactors are small, factory-built fission systems designed for transport and use in various environments, including remote sites, mining operations, and data centers. 

These reactors are designed to fit into standard shipping containers or onto flatbed trucks for deployment. The specific model intended for JBSA is the Antares R1, which uses sodium heat pipe-cooling and tri-structural isotropic (TRISO) fuel. 

These systems are designed to provide electricity for several years between refueling and do not require specialized infrastructure or a connection to external utility grids to operate.

According to the US Department of Energy, micro nuclear reactors are built with safety systems intended to prevent overheating or reactor meltdowns. 

The selection of JBSA for this program was based on several factors, including the installation’s available land, its current utility infrastructure, and its specific mission requirements. 

Brig. Gen. Randy Oakland, commander of JBSA and the 502d Air Base Wing, stated that energy resilience is necessary for sustaining base operations. He noted that if the site is finalized under this initiative, it would provide reliable support for the various missions hosted at the installation.

Demonstration to validate reactor physics

Antares is currently in the final phase of the Department of Energy’s Reactor Pilot Program, with a goal to achieve criticality—a stable, self-sustaining nuclear fission reaction—before July 4, 2026. 

Fuel fabrication for these initial reactors has been underway at BWX Technologies since October 2025. 

The company uses High Assay, Low Enriched Uranium (HALEU) fuel provided through a Department of Energy allocation.

The development process includes a Mark-0 demonstration to validate reactor physics, neutronics models, and control systems. Following this phase, Antares plans to use the same test facility for its Mark-1 electricity-producing reactor in 2027. 

The service targets 2028 or earlier for the first production deployments for defense and space customers. 

Under the initiative, Antares will be responsible for the siting, licensing, construction, operation, and eventual decommissioning of the R1 microreactors.