Nuclear stocks jumped in premarket trading. Nuscale Power up 16%; Centrus up 11%; Oklo up 9%; NANO Nuclear Energy up 6%; CEG, Uranium up 5%.

The U.S. military is making one of its most significant pushes yet into modern nuclear power with a program to put small reactors on Army bases across much of the country where strained power grids can't keep up with rising energy demands.

The Army on Tuesday unveiled the Janus Program, which aims to supply bases by 2028 with microreactors -- tiny reactors generating less than 20 megawatts of electricity, generally enough to power a small town. That is a fraction of the energy output that larger modern reactors can produce, but the microreactors are small enough to move on a containership or aircraft.

The reactors will help keep weapons powered and maintain critical base operations when other energy sources go down because of bad weather, cyberattacks or other grid disruptions, the Army said.

"What resilience means to us is that we have power, no matter what, 24-7," said Jeff Waksman, principal deputy assistant secretary of the Army.

The reactors will be owned and operated by commercial companies, although the Army and Energy Department will help with technical aspects and uranium fuel supply. The Army is in the process of selecting nine bases for the initial phase of the program, and by next year will choose the commercial vendors to build two microreactors apiece for each base, Waksman said.

Interest from the Army is a promising opportunity for nuclear-power startups that have raised billions of dollars for projects including small reactors, uranium enrichment and new fuel technologies but in many cases are years away from completing a product.

"The race today is to actually develop the capability. We are all trying to figure out who can turn these things on," said Isaiah Taylor, chief executive and founder of Valar Atomics, a microreactor startup. His two-year-old company, which has built one microreactor, plans to bid on the Janus contract.

Janus builds on more than six years of efforts by the Army and the Defense Innovation Unit, the arm of the Pentagon that works with technology startups, to acquire small and easily transportable nuclear reactors for bases in the U.S. and military operations overseas. The program is intended in part to better prepare the U.S. for potential war with China in the Pacific or conflict in the Arctic, Army officials said, which would bring major transportation and logistical challenges for supplies -- including power.

Bases in Texas and California have lost power in snowstorms, and others rely on aging public utility grids and fossil fuels for backup. Solar and wind power are intermittent replacements. Meanwhile, many of the Army's newer weapons, including drones and counterdrone and radar systems, require more energy, a Defense Department official said.

The nation's energy needs are soaring, driven in part by big-tech's quest to build power-hungry data centers to develop artificial intelligence. China's own energy advancements have framed the race for nuclear power as a national security imperative.

President Trump signed an executive order in May calling on the federal government to deploy modern nuclear reactors for national security purposes, and asking the secretary of the Army to start using reactors on military bases by September 2028.

The Army didn't provide a clear cost estimate for Janus, but said that some of the money would be pulled from the Defense Innovation Unit budget.