Interview, Fireside Chat
Radiant CEO Doug Bernauer on Portable Nuclear Microreactors & the Future of Clean Energy
- Radiant is developing portable, one-megawatt nuclear reactors designed to replace diesel generators in remote and off-grid locations, with a founding mission to enable life multi-planetary through space-ready nuclear technology.
- The company has committed to conducting its first fuel test in 2026, aiming to break a 50-year hiatus on new reactor designs being fueled in the U.S.
- Radiant raised approximately $60 million in total venture capital, including a $40 million Series B (April 2023) led by a16z with participation from Founders Fund and Decisive Point.
- In addition to equity, Radiant has secured seven government contracts totaling roughly $8.7 million in non-dilutive funding.
- The reactor core is four feet in diameter, containing approximately 120 million TRISO fuel particles (ceramic-coated uranium kernels), eliminating the risk of fuel melting up to 1,600°C.
- Unlike traditional light water reactors, the system uses helium gas as a coolant, which cannot become radioactive, absorb neutrons, or leak a liquid, ensuring no radioactive release to the environment.
- The 1 MW unit is designed for mass production at a rate of 50 reactors per year (one per week) from a factory line, with a projected capital cost in the tens of millions of dollars compared to the billions required for gigawatt-scale plants.
- Deployment requires only a 35-foot fence line with no heavy infrastructure, and the unit operates for five years on a single fuel load.
- A key differentiator is portability: customers can turn the system off and request Radiant to retrieve the unit, meaning no nuclear waste is stored on-site as the fuel is shipped away with the reactor.
- The technology is positioned to replace diesel generators in remote areas like coastal Alaska and inland mining sites, providing 1 MW of electricity and 2 MW of heat (up to 80°C) for water heating or industrial processes.
- Founder Doug Bernauer spent 12 years at SpaceX, working on Falcon 1, Falcon 9, Grasshopper, Hyperloop, and Mars systems, before founding Radiant in 2019 following the U.S. military's PELE program announcement for transportable air-deployable reactors.
- Co-founder Bob (a former Hyperloop colleague) leads software and cybersecurity efforts, while the team includes engineers from Naval Reactors, Idaho National Lab, Oak Ridge National Lab, and Tesla (referred to as "Master Car" in the transcript).
- Radiant utilizes digital twin technology and advanced simulation to work with the NRC on modernizing regulations, aiming to bridge the gap between public support for nuclear and the lack of recent physical development.
- The company plans to publicly release data from its current nuclear-grade graphite testing to help qualify domestic suppliers and advance the broader U.S. nuclear supply chain.
- Funding rounds are scheduled for the summer of 2024, marking the final investment opportunity before the first reactor fueling and testing in five decades.
- Operational timeline: 2024 will focus on final design and simulation to overcome "analysis paralysis," while 2025 is dedicated to physical construction and shipping the unit to the testing site (Idaho National Lab) before year-end.
- The reactor features an inherent passive safety shutdown via a negative thermal coefficient of reactivity; if the helium pump fails or temperatures rise, the system naturally becomes subcritical without human intervention.
- Radiant emphasizes a shift from bespoke, construction-heavy projects to a factory-based manufacturing model, drawing parallels to the mass production methods that drive down costs in aerospace and consumer electronics.