Westinghouse and Radiant were the initial companies selected to test their microreactor designs in DOME, the world's first microreactor test bed at Idaho National Laboratory.
July 1, 2025
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Washington, D.C. — The U.S. Department of Energy today made conditional selections for Westinghouse and Radiant to perform the first tests in the Demonstration of Microreactor Experiments (DOME) facility at Idaho National Laboratory. The DOME experiments will be the first of their kind in the world and will fast-track the deployment of American microreactor technologies to keep pace with the nation’s demand for more abundant, affordable, and reliable power. The first fueled reactor experiment will start as early as spring 2026.
“Microreactors will play a big role in expanding the use of nuclear power in the United States,” said Mike Goff, the Acting Assistant Secretary for Nuclear Energy. “Thanks to President Trump’s leadership, these DOME experiments will test new reactor designs that will be counted on in the future to reliably power our homes, military bases, and mission critical infrastructure.”
President Trump is committed to expanding the nation’s nuclear capabilities to reestablish the United States as a global leader in nuclear power. Today’s announcement unleashes American innovation and unlocks a new resource for private industry to help lower the risk of developing new reactor technologies in the United States.
DOME will be the first microreactor test bed in the world and leverages existing infrastructure at Idaho National Laboratory to safely house and test fueled reactor experiments that produce up to 20 megawatts of thermal energy. Data collected from the experiments will be used to commercialize each reactor technology.
Westinghouse (Etna, Pennsylvania) will test the eVinci Nuclear Test Reactor to inform the development of its commercial transportable microreactor that uses advanced heat pipe technology to passively cool the reactor. The eVinci reactor is designed to produce 5 megawatts of electricity on sites as small as two acres of land and could be used to power various applications from remote communities to mining operations or data centers.
Radiant (El Segundo, California) will test the Kaleidos Development Unit to advance the company’s commercial 1.2 megawatt electric high-temperature gas reactor design as a potential replacement for diesel generators. Kaleidos is designed to operate for five years before refueling and could provide reliable backup power to hospitals, military installations, and more.
The two reactor developers were competitively selected in 2023 to perform initial activities for potential testing in DOME. Both companies are currently working through the multi-phase DOE authorization process to support the design, fabrication, construction, and testing of each fueled reactor experiment.
The Department estimates each DOME reactor experiment will operate up to six months. The testing campaigns are self-funded by the applicants with the sequencing of experiments based on several criteria, including technology readiness, fuel availability, and a regulatory approval plan. Both companies are expected to meet certain milestones throughout the process to maintain their allotted time in DOME and to ensure efficient use of the test bed.
The DOME test bed is currently under construction and on track to receive its first experiment in early 2026. The facility is operated by DOE’s National Reactor Innovation Center, which enables access to the world-class capabilities across the Department’s national laboratories to accelerate the development of advanced reactor technologies.
DOE recently closed its first round of applications for scheduling experiments in DOME. The next call for applications is anticipated to be in the summer of 2026.
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