Antares secures $470 million Series C to develop nuclear reactors for US military
The funding round, led by Paradigm and Caffeinated Capital, brings Antares’s total capital raised to $604 million as the company moves toward commercial deployment of its TRISO-fuelled technology.
Nuclear power startup Antares has raised $470 million in a Series C funding round to develop small modular reactors (SMRs) specifically for United States Air Force bases. The investment, led by Paradigm and Caffeinated Capital, includes $370 million in equity and $100 million in debt, with participation from Industrious Ventures, Point72 Ventures, and Shine Capital. The deal underscores a broader surge in investor interest in advanced nuclear technologies, a trend driven by the escalating electricity demands of AI data centres and the wider electrification of the economy.
Antares is developing a reactor capable of producing between 100 kilowatts and 1 megawatt of electricity, a capacity sufficient to power up to 750 homes. The company’s design utilises TRISO fuel, which encapsulates uranium within carbon and ceramic shells. This fuel type is designed to prevent melting in high-temperature environments and can be cooled by gases such as helium or molten salts. The company’s demonstration reactor, the Mark-0, reached criticality on 4 June at the Idaho National Laboratory, marking a significant technical milestone ahead of its commercial ambitions.
The startup is one of three finalists in the Pentagon’s Advanced Nuclear Power for Installations program, which will test SMRs at Air Force bases in Colorado and Montana. Antares aims to bring its first electricity-producing reactor online next year, with full-scale deployments at US military installations planned for 2028. This strategic focus on the military sector provides a stable revenue stream, as the government is considered a price-insensitive customer compared to the broader commercial energy market.
This latest injection of capital brings Antares’s total raised funds to $604 million, according to a TechCrunch analysis of PitchBook data. The company previously closed a $96 million Series B round in December. The nuclear sector has seen significant capital inflows recently, including X-energy’s $1 billion initial public offering in April and nine-figure funding rounds raised by Radiant Energy, Standard Nuclear, and Last Energy since December.
Despite the influx of capital, advanced nuclear startups face substantial hurdles to commercialisation, including an immature US supply chain and difficulties in scaling production. While mass manufacturing is expected to reduce costs, industry analysts note that these benefits typically take at least a decade to materialise, and no startup has yet reached that stage. Lazard estimates that new SMRs will cost approximately $214 per megawatt hour, making them more expensive than most new power plants, including all but the most expensive gas turbines. Antares has not disclosed its specific pricing structure.
