Radiant Submits Safety Analysis to U.S. Department of Energy in Major Milestone for Start Up of First Reactor

Submission begins 45 day approval period, paving way for start up of first reactor at INL's DOME facility next year.

November 17, 2025

November 17th, 2025 – Radiant, a leader in portable, mass-produced nuclear generators, announced today that it submitted its DOE Authorization Request for Kaleidos (DARK) to the U.S. Department of Energy (DOE) for review earlier this month. This submission meets the intent of the Preliminary Documented Safety Analysis (PDSA), an essential milestone that keeps the company on track to start up its first reactor next year at the National Reactor Innovation Center's (NRIC) DOME facility at Idaho National Laboratory (INL).

The submission begins a 45-day DOE approval period under the Department's new Authorization Pathway for Nuclear Facilities, which establishes a clear and phased regulatory path for novel nuclear technologies. Approval of the PDSA will close out the second of three phases in that process, paving the way for Radiant to start up its reactor.

"Our approach aligns directly with DOE Standard 1271-2025 and the Department's response to the President's Executive Order accelerating advanced nuclear deployment," said Rita Baranwal, Chief Nuclear Officer of Radiant. "This submission represents the culmination of a rigorous design and safety validation effort."

The Kaleidos Demonstration Unit will be one of the first nuclear reactors to operate under DOE's new framework, and the first ever to start up at INL's new DOME facility.

"Radiant's submission of its safety analysis for Kaleidos represents exactly the kind of rapid innovation America needs to meet aggressive nuclear deployment timelines and reclaim global leadership in nuclear energy," said INL Director John Wagner. "INL is proud to partner with companies like Radiant as they accelerate next-generation reactor designs from concept to reality."

For more information on Radiant and the Kaleidos generator, visit www.radiantnuclear.com.

About Idaho National Laboratory

Battelle Energy Alliance manages INL for the U.S. Department of Energy's Office of Nuclear Energy. INL is the nation's center for nuclear energy research and development, and also performs research in each of DOE's strategic goal areas: energy, national security, science and the environment. For more information, visit www.inl.gov. Follow us on social media: Facebook, Instagram, LinkedIn and X.