Radiant Nuclear has raised over $300 million in a new funding round, bringing its valuation to more than $1.8 billion. The investment, led by Draper Associates and Boost VC, includes participation from Ark Venture Fund, Chevron Technology Ventures, Founders Fund, Friends and Family Capital, and other backers. Previous investors such as Andreessen Horowitz, DCVC, Giant Ventures, and Union Square Ventures also contributed. The company is developing a compact, 1-megawatt nuclear microreactor designed to be transported on a semi-truck. The reactor uses helium cooling and TRISO fuel—tiny ceramic-coated particles of uranium and graphite—engineered to withstand extreme temperatures and resist meltdown. It is built to operate for five months between refueling and will have a 20-year operational lifespan. After that, Radiant will reclaim the unit for decommissioning. Radiant’s target markets include remote commercial sites and military installations, where it aims to replace diesel generators. Customers can either purchase the reactors outright or opt for a power purchase agreement. The company has already secured a deal with data center developer Equinix to supply 20 units, highlighting the growing interest in nuclear power as a reliable energy source for AI-driven data centers. A key milestone is the construction of a demonstration reactor at the Idaho National Laboratory, with testing expected to begin in summer 2026. Radiant is one of 11 companies selected for a U.S. Department of Energy initiative that fast-tracks regulatory approval timelines, aiming for three first-of-a-kind reactors to achieve criticality by July 4, 2026. While the program does not offer direct funding, it streamlines the path to deployment. The recent surge in nuclear startup funding—following large rounds from X-energy, Last Energy, and Aalo Atomics—has sparked debate about whether the sector is entering a bubble. The momentum is closely tied to the soaring energy demands of AI and data centers, which are driving tech firms to seek stable, high-capacity power sources. While some startups may struggle to scale beyond their first unit, Radiant’s progress, strong partnerships, and clear roadmap suggest it is well-positioned to deliver. Still, the next 12 to 24 months will be critical, as the industry moves from promise to real-world deployment.