Radiant Raises Over $300 Million in New Funding to Mass-Produce Portable Nuclear Reactors

Radiant, a clean energy startup building a nuclear microreactor, led by Doug Bernauer, Dr. Rita Baranwal, Dr. Mike Starrett, and others, has raised more than $300 million in a new round of funding led by Draper Associates and Boost VC, with additional financial commitments from current investors, reinforcing their continued confidence in Radiant’s positioning in the microreactor space. As part of this latest capital raise, Radiant also received additional investment from Founders Fund, ARK Venture Fund, Chevron Technology Ventures, and others.

“Micro-scaled nuclear reactors, mass-produced for the first time, have the potential to change how the public thinks about nuclear energy fundamentally,” said Doug Bernauer, CEO and Founder of Radiant. “This funding allows us to build our factory and stay on track for our DOME program, where we aim to achieve a self-sustained chain reaction using a reactor designed, built, fueled, and operated by Radiant in partnership with Idaho National Laboratory.”

Radiant remains on track to start up its first reactor next year, the Kaleidos Demonstration Unit (KDU) at Idaho National Laboratory’s DOME facility. Its factory-built, transportable nuclear generators are designed to deliver always-on power for defense, disaster response, remote industry, and critical infrastructure where traditional energy systems fall short.

Investors consistently point to Radiant’s execution as its defining strength. Backers, including Tim Draper, Andreessen Horowitz, DCVC, Boost VC, and others, highlight the team’s ability to hit milestones on or ahead of schedule, move portable micro-nuclear reactors from concept to deployment, and scale production in months rather than years. Collectively, they see Radiant as one of the most execution-ready teams in next-generation energy, building reliable, resilient nuclear power for defense, critical infrastructure, and energy security where traditional systems fall short.

Today’s news caps a breakout year for Radiant. In under six months since its last raise, the company has:

• Upgraded leadership, hiring top nuclear, engineering, and manufacturing talent, including former DOE Assistant Secretary Dr. Rita Baranwal as Chief Nuclear Officer.

• Secured DOE selection to run the first Kaleidos microreactor test at Idaho National Laboratory’s DOME facility, starting summer 2026.

• Advanced rapidly on regulation, completing key safety and authorization milestones to stay on track for testing.

• Signed historic defense agreements, including the first deal to deploy mass-manufactured microreactors on a U.S. military base.

• Joined the President’s Nuclear Reactor Pilot Program, positioning Kaleidos for streamlined deployment.

• Locked in commercial demand, with a 20-reactor purchase agreement from Equinix.

• Led the HALEU fuel market, becoming the first reactor company to sign DOE fuel contracts and a binding enrichment deal with Urenco.

• Announced the world’s first microreactor factory in Oak Ridge, Tennessee, targeting production of 50 reactors per year.

• Began first reactor assembly, marking the transition from design to hardware ahead of next summer’s startup.