Radiant’s Kaleidos to be first new reactor tested at DOME

It’s one thing to design a revo­lu­tionary microre­actor on paper. It’s another to actually build and test one — especially when it’s the first advanced nuclear reactor to be turned on in the Western world.

That’s exactly what Radiant is about to do. Radiant’s Kaleidos microre­actor will be the first new reactor design ever tested at the Department of Energy’s newly repurposed DOME (Demon­stra­tion of Microre­actor Experiments) facility at the Idaho National Laboratory (INL). 

For Radiant, going first at DOME represents the gateway to commer­cial­izing Kaleidos: a compact, portable, 1MW microre­actor that can be transported by truck and installed in days. It’s designed to replace diesel generators in off-grid or remote locations, from military bases to disaster zones. 

An iconic structure originally built in the 1960s to house the Exper­i­mental Breeder Reactor II, DOME has been repurposed as the first dedicated facility in the world designed specif­i­cally to test fueled microre­ac­tors — making it a one-of-a-kind national resource. By enabling reactor startups to demonstrate performance and safety in a real-world setting, DOME helps derisk innovation, accelerate licensing, and build public confidence. It’s also a powerful example of how the Department of Energy and national labs like INL can help fast-track commer­cial­iza­tion without compro­mising on oversight or rigor.

This test at DOME is happening because Radiant is executing on every front. This year, they secured through a highly competitive DOE program an allocation of high-assay low-enriched uranium (HALEU)—fuel that enables Kaleidos’s compact design and extended time between refueling. Radiant also just signed the first-ever agreement to deliver a mass-manu­fac­tured nuclear microre­actor to a U.S. military base; under the Department of Defense’s Advanced Nuclear Power for Instal­la­tions (ANPI) program, Radiant will deploy Kaleidos reactors to an Air Force base by 2028 — delivering resilient, cyber-secure power within 48 hours of arrival. And Radiant continues to strengthen their leadership team, most recently with Dr. Rita Baranwal, former Assistant Secretary for Nuclear Energy and West­ing­house CTO, joining as their first Chief Nuclear Officer.

Radiant’s momentum — and this first-of-its-kind demon­stra­tion at DOME — signal that U.S. advanced nuclear is finally moving from promise to reality. DCVC is proud to stand behind Radiant as they scale Kaleidos from testbed to real-world impact — helping deliver carbon-free, resilient energy exactly where and when it’s needed most.