Antares Raises $470M to Build Nuclear Reactors for the US Military

Antares Nuclear has raised $470 million in a Series C round to build small modular reactors specifically designed for US military bases, pushing the young nuclear startup's total funding to $604 million as it races toward its first electricity-producing reactor.

How the round breaks down

The Series C combined $370 million in equity funding with $100 million in debt financing, a structure that reflects both investor confidence in the company's technology and the capital-intensive nature of actually building nuclear infrastructure, where debt financing is often used to fund the kind of physical construction and licensing costs that pure equity rounds are less suited to cover. Paradigm and Caffeinated Capital led the round, with Industrious Ventures, Point72 Ventures and Shine Capital also participating.

What the reactors are actually built for

Antares is designing small modular reactors, ranging from 100 kilowatts up to 1 megawatt of capacity, sized to power individual military installations rather than feed into a wide civilian grid. At the top end of that range, a single reactor could supply enough electricity for up to 750 homes, giving a sense of scale: these are not city-sized power plants, but self-contained systems meant to give a military base a reliable, independent power source that isn't dependent on a vulnerable regional grid.

The technology and the milestone already hit

The company uses TRISO fuel, a form of nuclear fuel encased in layers of protective material that is widely considered a safer alternative to traditional nuclear fuel rods, reducing the risk of fuel damage releasing radioactive material even under extreme conditions. Antares has already cleared a significant technical milestone: its Mark-0 demonstration reactor reached criticality, meaning it achieved a sustained nuclear chain reaction, at Idaho National Laboratory on June 4.

The Pentagon connection

Antares is one of three finalists selected by the Pentagon for its Advanced Nuclear Power for Installations program, an initiative specifically aimed at giving military bases resilient, on-site power generation. As part of that program, the company is testing its small modular reactors at Air Force bases in Colorado and Montana, giving it a direct government testing pathway rather than needing to prove the technology purely through commercial deployment first.

Why the cost matters

Independent financial analysis firm Lazard estimates the cost of power from these reactors at roughly $214 per megawatt hour, a figure that puts the technology well above the cost of conventional grid power in most markets today. That price premium is the tradeoff the Pentagon appears willing to accept for the specific value small modular reactors offer: energy independence and resilience for critical military infrastructure, rather than the cheapest possible electricity.

The timeline ahead

Antares is targeting 2027 for its first reactor capable of actually producing electricity, with deployments at US military installations planned for 2028, and broader small modular reactor rollout expected in the early 2030s if the technology continues to perform as designed through the Pentagon's testing program. That timeline places Antares among a small cluster of startups racing to commercialize small modular reactor technology at a moment when both national security planners and climate-focused investors have converged on nuclear power as a solution worth funding aggressively, even at a meaningfully higher cost per unit of electricity than conventional alternatives.