Radiant Industries has achieved an industry first by securing US Department of Energy (DOE) approval for its Documented Safety Analysis (DSA), officially clearing its Kaleidos microreactor design for full-power operations. This allows Radiant to advance to the final operational Readiness Review before starting nuclear testing at the Idaho National Laboratory (INL).
The approval transitions Radiant from a theoretical design into a comprehensive, multi-phase testing campaign that will generate real operating data.
Unlike standard preliminary tests that solely check if a design can sustain a controlled nuclear chain reaction (criticality), this safety approval enables Radiant to evaluate its integrated systems under sustained, high-temperature, full-power operating environments.
The upcoming five-phase test campaign will take place within the National Reactor Innovation Center’s (NRIC’s) Demonstration of Microreactor Experiments (DOME) test bed at INL. The campaign targets 60 effective full-power days (EFPD) spread across several months. This includes a 150-hour continuous full-power run executed entirely without human operator intervention, validating the system’s automated baseline safety.
Because the microreactor undergoing testing uses the exact same design and custom-engineered fuel intended for commercial production, the data harvested at INL will directly streamline commercial licensing.
Radiant plans to mass-produce the Kaleidos units at its R-50 manufacturing factory in Oak Ridge, Tennessee. The company has already locked in initial commercial delivery agreements slated for 2028 to secure energy resilience for mission-critical infrastructure across several military installations, including Buckley Space Force Base, Fort Benning, and the Naval Weapons Station Crane.
“DOE’s approval is a major milestone because it reflects the scope of what we are preparing to demonstrate with Kaleidos,” said Dr Rita Baranwal, Chief Nuclear Officer at Radiant. “We are testing the design of our commercial reactor, the same unit – from fuelling through 150 hours of continuous operation without operator assistance and beyond. This approval for full power demonstration is a first within the microreactor industry. It moves us forward to test our complete reactor system under sustained operating conditions.”
With the Kaleidos DSA approved, Radiant is cued for DOE’s Readiness Review, which will assess whether Kaleidos and the team responsible for operating it are prepared to begin nuclear operations. Following successful completion of the review, Radiant will fuel Kaleidos and begin its five-phase test campaign at the National Reactor Innovation Center’s Demonstration of Microreactor Experiments (DOME) facility at INL.
“The Department of Energy is providing technical oversight to help companies like Radiant safely accelerate the development and testing of next-generation nuclear technologies, paving the way for faster commercial deployment of reliable, nuclear energy needed to power American industry, strengthen our national security and restore U.S. leadership in nuclear innovation,” said acting Deputy Assistant Secretary for Nuclear Reactors Chimi Zacot.
