Antares Secures $470 Million to Deploy Mini Nuclear Plants at U.S. Bases

Antares says the cash will accelerate development of compact reactors aimed at improving power reliability for military installations, with a demonstrator already achieving sustained fission.

Antares Nuclear announced Monday that it has closed a $470 million Series C financing to push small modular reactors (SMRs) toward deployment on U.S. military sites. The round, led by Paradigm and Caffeinated Capital and joined by Industrious Ventures, Point72 Ventures and Shine Capital, included roughly three-quarters in equity and one-quarter in debt. Company officials framed the funding as a step toward hardened electricity on forward bases and energy independence for installations.

The startup is building an SMR that can produce from 100 kilowatts up to 1 megawatt — a range its engineers say could serve the electrical needs of a few hundred homes. Antares’ design employs TRISO fuel, in which fissile material is encased in layered ceramic and carbon coatings; that geometry is intended to retain radioactive material at high temperatures and allows cooling with gases such as helium or with molten salts. Supporters point to those features as reducing some failure modes tied to older reactor types.

Antares’ Mark-0 demonstration unit reached sustained fission reactions on June 4 at the Idaho National Laboratory, the company said. The firm is among three finalists in the Defense Department’s Advanced Nuclear Power for Installations effort, which will test small reactors at Air Force sites in Colorado and Montana. Antares plans to put a reactor that actually generates electricity into service next year and to begin stationing units at select military posts by 2028.

Investor interest in fission has surged alongside a boom in data center construction and broader electrification, drawing large sums into companies pursuing next-generation reactors. Earlier this year X-energy closed a $1 billion financing, and since last December several startups — including Radiant Energy, Standard Nuclear and Last Energy — have announced nine-figure raises. Antares itself completed a $96 million round in December; TechCrunch’s review of PitchBook records puts the company’s lifetime financing at about $604 million.

Industry veterans caution that capital is only one part of the challenge. U.S. supply chains for advanced reactor components remain thin, and builders haven’t yet shown that mass production of SMRs will drive down costs quickly. Independent cost analyses from Lazard peg electricity from first-of-a-kind SMRs at about $214 per megawatt-hour, a level that would be pricier than nearly all new gas-fired plants. Antares has not released pricing, and analysts say the military’s willingness to pay for resilient power makes defense contracts an obvious near-term market for costly early units.

“A military buyer values uninterrupted energy and readiness in ways civilian utilities often don’t,” said a former military energy officer who reviewed the program, noting the tradeoff between higher upfront costs and the strategic benefits of on-site generation. He added that widespread civilian adoption will likely hinge on whether manufacturers can cut unit costs over many years of repeat production.