Naval Weapons Station Crane in Indiana is slated to host a factory-built nuclear reactor that arrives largely assembled. The Navy chose Radiant’s Kaleidos, a 1 MW high-temperature gas-cooled microreactor, for the site under the Army-led Janus Program. Once running, it would be the first power-producing nuclear reactor in Indiana.
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Radiant says it is now the only company selected by all three U.S. military departments, since the Army and the Air Force picked it for their own microreactor programs. The Navy selection was reported on 22 October 2026, after the Department of War announced in September that a commercially owned and operated micromodular reactor would go to Crane. No deployment date, contract value or operating timeline has been made public.
Kaleidos: a transportable reactor with five years between refuelings
According to World Nuclear News, which reported the selection, the Kaleidos is a factory-built, transportable 1 MW high-temperature gas-cooled microreactor that Radiant describes as plug-in ready. A unit can supply up to five years of power before it needs refuelling, over a 20-year life. It requires no cooling water, no major excavation and no extensive construction on site, properties that suit an installation without coastal water access.
The design is being proven in Idaho. Radiant’s reactor left El Segundo, California, on 12 August 2026 and began its trip to Idaho National Laboratory, where the DOME test bed, built in a repurposed experimental breeder reactor containment, runs a five-phase programme from zero-power criticality to full heat and power. The plan ends with a 150-hour continuous run without operator assistance. The Department of Energy gave Radiant a year of exclusive access to the facility after a competitive selection.
Fuel and logistics come from the Idaho coverage as well. The unit is designed to be moved by land, sea and air, and it uses TRISO fuel fabricated by Standard Nuclear, loaded after installation under Department of Energy and Idaho National Laboratory oversight. Radiant targeted completion of testing in the third quarter of 2026, and said in its own statement that the machine on the test stand is the same design, at the same scale, with the same commercial fuel load as the units it will sell.
The Janus Program and the 2028 deadline
Janus is the Army’s next-generation nuclear power programme, launched in October 2025 to deliver resilient, secure and assured energy for national defence installations and critical missions. Jeff Waksman, the Army’s principal deputy assistant secretary for installations, energy and environment, said the programme was built from day one to deliver real, reliable hardware and systems, and that the Army was glad to partner with the Navy to place a Janus reactor at Crane.
The Crane plant came out of a September announcement. World Nuclear News reported on 14 September 2026 that the Department of War plans a commercially owned micromodular reactor there, to be the Navy’s first shore-based advanced reactor of that kind. The goal ties to Executive Order 14299, which targets operation of an Army-regulated reactor at a domestic military installation by 30 September 2028. Mike Dodd, Assistant Secretary of War for Critical Technologies, said the standard is to field and deploy capability within 24 months or less. Senator Todd Young called the announcement exciting news for Indiana, where no reactor has yet fed power to a grid or a base.
Radiant’s three-service footprint and the path to Crane
Before the Navy pick, the Army selected five microreactor developers for five installations, and the Air Force announced its own picks, described in World Nuclear News coverage of Air Force selections. Radiant says it will deliver a Kaleidos to Buckley Space Force Base by 2028 under its Air Force agreement, with its testing campaign in Idaho serving as the proof for that delivery. The company is building units at its R-50 factory in Oak Ridge, Tennessee, where a Part 70 licence application is under review at the Nuclear Regulatory Commission.
For Crane, Radiant says the project goes through design refinement, prototype testing, environmental review, site preparation and regulatory coordination before deployment. It will work with the Navy, the Army, the Defense Innovation Unit, the Nuclear Regulatory Commission and other partners, with technical support from the Naval Nuclear Propulsion Program. Radiant publishes company updates at radiantnuclear.com, and the World Nuclear Association keeps an overview of small nuclear power reactors that places microreactors in context.
One detail remains unclear from the public reporting: the Kaleidos is described as a 1 MW machine, and Radiant’s own statements in the Idaho coverage use 1 MWe in places while also referring to thermal operation, so whether the 1 MW is electric or thermal depends on which statement is read, and a rating for the Crane unit has not been published. Until Radiant or the Navy states the rating for the Crane unit, the electrical output Indiana will actually receive stays unconfirmed.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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