Radiant Microreactor Safety Analysis Report Approved by U.S. Department of Energy

Recently, U.S. microreactor developer Radiant Industries (Radiant) announced that the Safety Analysis Report (DSA) for its Kaleidos microreactor has been formally approved by the U.S. Department of Energy (DOE), granting permission for full-power operation. This important milestone marks the company's formal entry into the operational maturity review phase and its move to Idaho National Laboratory (INL) for comprehensive verification testing.

This approval enables Radiant to successfully transition from theoretical design to a comprehensive multi-phase testing stage. Unlike conventional criticality tests that merely verify whether a controlled chain reaction can be maintained, this safety approval allows Radiant to evaluate its integrated system performance under sustained, high-temperature, and full-power operating conditions. The five-phase testing campaign, to be conducted at the DOME test bed of the National Reactor Innovation Center (NRIC) at INL, plans to accumulate 60 equivalent full-power days (EFPD) over several months, including a continuous full-power run of up to 150 hours without human intervention, to rigorously validate the system's automated safety baseline.

Because the test microreactor uses the same custom design and fuel as future commercial production, the extensive real operating data obtained from testing will directly inform and accelerate the commercial licensing process. Radiant plans to advance batch production of Kaleidos units at its R-50 manufacturing facility in Oak Ridge, Tennessee, and plans to deliver commercial units starting in 2028 to key military installations including Buckley Space Force Base, Fort Benning, and Naval Weapons Station Crane, to provide reliable energy resilience assurance.

Radiant Chief Nuclear Officer Rita Baranwal noted that this industry-first full-power demonstration approval fully validates Kaleidos's overall design capability from nuclear fuel loading to achieving unattended long-cycle operation. Chimi Zacot, Acting Deputy Assistant Secretary for Nuclear Reactors at DOE, stated that the Department of Energy is accelerating the commercial deployment of next-generation nuclear technologies through comprehensive technical oversight, further consolidating the United States' leadership position in global nuclear innovation.