Valar Atomics Raises $1B Series B to Bring ‘Manufacturing Economics’ to Nuclear Power

Nuclear power is one of the world’s most abundant, carbon-free energy sources — yet it has long been saddled with one of the industry’s worst cost curves. More than 70 years after the first reactors were built, conventional plants still cost a fortune and take decades to complete, even as forecasts point to a doubling of energy demand driven by AI data centers.

Valar Atomics, a U.S. small modular reactor (SMR) startup, aims to fix that curve by bringing manufacturing economics to nuclear. Rather than building reactors one bespoke project at a time, Valar wants to mass-produce them like factory hardware — pursuing a vertically integrated, hardware-first model in which it even produces its own fuel in labs placed alongside the reactors that will run it.

The company has hit a string of firsts. On June 18, its Ward 250 reactor achieved self-sustaining criticality, making Valar the first company ever to take a reactor critical outside a national lab. A week later, it used Ward 250 to power an NVIDIA Blackwell system in a live broadcast — the first time an advanced reactor directly powered AI infrastructure — and announced a collaboration with NVIDIA on a waterless 30 MW “AI factory.” Ward 250 is a helium-cooled, TRISO-fueled high-temperature gas reactor.

Founder and CEO Isaiah Taylor started Valar three years ago. Within two years the company completed its non-nuclear Ward Zero prototype, achieved cold criticality of its NOVA core at Los Alamos National Laboratory, and was selected for the U.S. Department of Energy’s Nuclear Reactor and Advanced Nuclear Fuel Line pilot programs.

Valar announced a $1 billion Series B led by Sequoia Capital, with Sequoia partner Shaun Maguire joining the board. New and returning investors including Atreides Management, Conviction, Point72, and Valor Equity Partners also participated. Separately, the company secured a $200 million credit facility with Erebor Bank as administrative agent, alongside J.P. Morgan, Crescent Cove, and Hercules Capital.

Valar did not disclose its valuation, but Bloomberg reported the round values the company at $6 billion — triple its prior mark. The capital will fund Valar’s shift from demonstrating a single reactor to mass-producing fleets of them. Each operating reactor feeds engineering and manufacturing data into the next, a “continuous learning loop” the company says will steadily compress build times: its NOVA core took two years, while taking Ward 250 critical took seven months.

An SMR gold rush for the AI era

Surging power demand from AI data centers has turned small modular reactors into a magnet for capital. X-energy, which uses the same high-temperature gas, TRISO-fuel approach as Valar, has raised $700 million, while portable-reactor maker Radiant closed a $300 million Series D. Others range from micro-reactors for military bases to seaborne SMRs. Valar’s pitch is that it has already taken a reactor critical outside a national lab and is running it in production, while internalizing fuel production for true vertically integrated mass manufacturing.