Microreactor startup Valar Atomics raises $1B

Valar Atomics, the three-year-old microreactor developer that has a forged a close relationship with the Trump administration, has raised $1 billion in its Series B funding round as investors increasingly bet that the White House’s overhaul of nuclear regulations will clear the way for the country’s first big atomic buildout in more than half a century.

On Monday, the Torrance, California–based startup announced its latest funding round, led by venture capital giant Sequoia, will be used to lay the groundwork for commercialization of Valar’s 5-megawatt Ward 250 reactor, which uses helium as a coolant instead of water. The reactor design has yet to receive approval from the U.S. Nuclear Regulatory Commission.

“So, what does the new Series B financing mean for Valar? It allows us to make the next mission critical evolution: Valar will transition from demonstrating the operability of an integrated reactor system to producing fleets of them en masse,” Valar founder and CEO Isaiah Taylor said in a post on the company website. ​“This has been Valar’s mission since its inception.”

It’s a milestone for a company that once drew derision within the nuclear industry over audacious claims its 27-year-old founder made on social media to back up a lawsuit against the NRC. The young executive’s showmanship, shrouded in patriotic language, attracted attention from Republican officials. Before long, Valar had emerged as what Mother Jones called ​“the Trump administration’s favorite nuclear startup.”

Last August, the Department of Energy selected Valar as one of 10 companies to take part in a new pilot program that aimed to help next-generation reactor startups split atoms for the first time. A month later, the agency named the company as one of four to take part in a separate pilot program to develop new supply chains for nuclear fuel. Two months after that, Valar became the first venture-backed startup to split atoms using an experimental core at Los Alamos National Laboratory.

In February, Valar made history by loading the parts for its Ward 250 onto a C-17 Globemaster III aircraft at the March Air Reserve Base in California and flying them to Utah’s Hill Air Force Base. The airlift, touted by the Trump administration as ​“groundbreaking,” was the first demonstration that a microreactor could be wholly transported by plane. In June, Valar split atoms with its prototype Ward 250, becoming the second company in the pilot program to do so.

The new funding, the company said Monday, will allow it ​“to fully execute a vertically integrated, hardware first approach; one that encompasses everything from reactor deployment and long-term operations to fuel production.”

The company faces significant hurdles to realize that vision. The U.S. operated what’s known as a high-temperature gas-cooled reactor back in the 1970s. The Fort St. Vrain nuclear station, Colorado’s only such facility, shut down after a decade of costly maintenance issues and outages. It was replaced with a natural gas–fired plant. A handful of similar reactors have been built around the world, but primarily operated as experimental units.

China started construction on its first major high-temperature gas-cooled reactor in 2012, and split atoms for the first time in 2021. But Beijing really reignited the race to commercialize the technology, which could help avoid tricky questions around using water for cooling, in December 2023. That’s when China’s first 150-megawatt, helium-cooled reactor began selling electricity to the grid. Two years later, China launched a new industrial alliance to hasten the development of high-temperature gas-cooled reactors. In January, Beijing kicked off construction on its second such reactor, which will have four times the capacity of the first one.

At a moment when Europe’s heat wave is forcing inland nuclear stations cooled with river water to cut production, high-temperature gas-cooled reactors look particularly promising.

But developers of small modular reactors, which produce less than 300 megawatts each, and microreactors, which produce less than 20 megawatts each, still need to prove that the technology makes economic sense. Historically, reactor companies have increased profits by building larger, higher-output units — not by selling a high volume of smaller ones.

Valar also intends to manufacture its own fuel. That comes with its own steep challenges, particularly since the company is using a complex fuel form known as TRISO. Currently, only a handful of domestic suppliers are working to ramp up production.

Even if Valar can secure the fuel it needs and prove that assembly-line reproduction is good business, the company will still face competition from serious contenders with deep-pocketed backers.

Kairos Power, which broke ground on its first plant in Tennessee earlier this year, is backed by Google. X-energy, in which Amazon took an equity stake in 2024, won a key federal approval for its first project in May.

Neither of those companies is seen as having particular political leanings. But Valar’s ties to the Trump administration, a boon today, could become a liability whenever Democrats retake power.

Already, President Donald Trump’s personal ties to the nuclear industry are inviting scrutiny. Valar’s latest fundraising may only add more. The Sequoia partner who led the fundraising round is Shaun Maguire, a vocal Trump supporter who became a lightning rod last year over controversial remarks he made that were widely condemned as bigoted against Muslims. Maguire will join Valar’s board as part of the deal.