A California-based developer of microreactors has completed a critical passive cooldown demonstration of its prototype Kaleidos system. Developed by Radiant Industries, the Kaleidos microreactor is one of the designs that are on track to be part of a historic test at Idaho National Laboratory (INL) in the world's first microreactor test bed as early as mid-2026.
The completion of its front-end engineering and experiment design (FEEED) phase at the INL is a major step to bringing the world's first factory-constructed microreactors to market. The demonstration of the passive cooldown system, which took place on September 17th, showcases the reactor's ability to safely shut down and cool off without power. Recent tests have shown that the reactor can be deployed in urban areas.
Radiant claims that the reactor safety system triggers a shutdown within 300 milliseconds of detecting an emergency condition. The company remains on schedule to conduct a full test of the Kaleidos microreactor at the Idaho National Laboratory in 2026. This would make it the first new reactor design to be operated in 50 years.
The recent FEEED process supports developers in designing and planning for the fabrication, construction, and potential testing of fueled reactor experiments at the Demonstration of Microreactor Experiments (DOME) microreactor test bed. The company was competitively selected last year to complete the FEEED process, which includes developing a detailed schedule, budget, design, and test plan for the experiment, as well as a detailed preliminary safety report on its design to ensure safe operations during testing.
Radiant's Chief Operating Officer, Tori Shivanandan, stressed that completing FEEED is a significant milestone towards their fueled nuclear test at INL’s DOME facility. "We are excited to continue partnering with the lab going forward," added Shivanandan. The company has also secured backing from the U.S. Department of Energy for Detailed Engineering and Experiment Design (DEEP).
The selection by DOE takes Radiant into the next phase of experiment design for the test of its 1 MW Kaleidos microreactor at the DOME facility, marking another significant step toward commercialization. A critical part of Radiant's phase two work will include developing documentation for the Preliminary Documented Safety Analysis (PDSA) and implementing critical design refinements. The PDSA represents 90% design completion and builds on the Conceptual Safety Design Report. It provides a thorough safety analysis for the reactor.
"This award represents a major milestone in our collaboration with INL. The United States urgently needs to build and deploy new reactors, and the DOME demonstrations show the American people that this future is not just possible - it's within our grasp," said Shivanandan. "The support from the DOE and INL is instrumental in our journey to bring this game-changing clean energy solution to market and unleashing the full potential of Kaleidos, proving that together, we can make it happen."