Nuclear power startup Antares announced on Monday, July 27, 2026, that it has raised $470 million in a Series C round to build small modular reactors (SMRs) for US military bases. The round was co-led by Paradigm and Caffeinated Capital, with participation from Industrious Ventures, Point72 Ventures, and Shine Capital, consisting of $370 million in equity and $100 million in debt. This is one of the largest investments ever made in an advanced nuclear reactor startup, reflecting the market's growing appetite for power sources that can fuel AI data centers and critical infrastructure.
Antares' reactor is an SMR capable of producing between 100 kilowatts and 1 megawatt of electricity — enough to power up to 750 homes. Like many other advanced nuclear startups, the design uses TRISO fuel, which encapsulates uranium in carbon and ceramic shells. The billiard ball-sized spheres are cooled by gases like helium or molten salts, and the coating is designed to prevent the fuel from melting in typical high-temperature reactors, effectively eliminating the meltdown risk that haunts traditional reactors.
Antares' demonstration reactor, the Mark-0, achieved criticality on June 4, 2026, at the Idaho National Laboratory, becoming one of the first privately developed advanced reactors to reach this milestone under the Department of Energy's Reactor Pilot Program. The company 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 CEO Jordan Bramble said the company aims to have its first electricity-producing reactor online next year, with deployments at US military installations planned for 2028. The broader context is the boom in nuclear energy investment in the United States driven by massive AI data center construction and the electrification of the economy. In April, X-energy raised $1 billion through an IPO, and Radiant Energy, Standard Nuclear, and Last Energy have each raised nine-figure rounds since December. Altogether, Antares has raised $604 million.
However, the path to large-scale commercialization faces significant hurdles. The US SMR supply chain is still immature, and mass manufacturing — which theoretically would reduce costs — typically takes at least a decade to materialize. Lazard estimates that early SMRs will cost about $214 per megawatt-hour, more expensive than most power sources. Unsurprisingly, Antares chose to pursue military contracts: the Pentagon is a famously price-insensitive customer willing to pay more for energy resilience at strategic bases.
The Pentagon's interest in microreactors is not coincidental. US military bases consume enormous amounts of energy and, in many cases, depend on civilian power grids that can be vulnerable to cyberattacks or disruptions. Having an autonomous, compact, low-carbon power source at each base dramatically reduces logistical vulnerability. The US Army's Janus program, launched in October 2025, set the goal of installing a nuclear reactor on a military base by September 2028 — exactly the timeline Antares is pursuing. If successful, Antares could open a billion-dollar market not just in the US but also among NATO allies seeking similar energy resilience solutions. The company is also positioned to serve the growing demand from data center operators who need reliable, carbon-free baseload power for AI compute clusters.
Sources: TechCrunch, Reuters, Pulse 2.0
