U.S. Army Targets 2027 Start for Base Microreactor

The U.S. Army is moving to restore organic nuclear power on its installations, targeting a first microreactor groundbreaking in 2027 and an initial criticality milestone in 2026—part of a new Janus Program designed to harden bases against grid outages and rising demand.

What the Janus Program Plans

Army leaders introduced Janus at the AUSA meeting, describing commercially owned and operated reactors that deliver resilient, on-base power for critical missions. Officials said they expect “a small nuclear reactor [to] go critical by July 2026” and that “construction will not begin until 2027,” framing the schedule as ambitious but achievable with industry help.

The program’s stated goal is assured energy for installations if the wider grid goes down, building on recent policy directives to accelerate advanced nuclear for national security sites.

Fuel, Safety, and Oversight

Officials acknowledged enrichment constraints but argued the shortfall is solvable as DOE funds new domestic fuel-line pilots and advances reactor testing outside national labs. “It’s not there today, but it will be,” one senior energy official said of enrichment, while an Army energy leader emphasized that microreactors contain “very small amounts of fissile material,” calling them unattractive proliferation targets.

The acquisition will use milestone-based contracts with the Defense Innovation Unit, which has already named eligible companies for installation projects.

Context: From Pele to Eielson

Janus draws lessons from the Pentagon’s Project Pele mobile reactor effort and parallels the Air Force pilot naming Eielson Air Force Base in Alaska the preferred site for a microreactor planned to come online by 2028. Separately, the Army says AI-driven systems and electrified base loads amplify energy needs—one driver for dedicated nuclear power.

Companies developing transportable units, including those pursuing agreements with the Air Force, see defense installations as early adopters as licensing and supply chains mature.