Another day, another nine-figure round for a nuclear startup.
Radioactive nuke said today that it has raised more than $300 million, just one day after Last Energy announced that it had raised $100 million. Three weeks ago, X-energy raised $700 million and in August Aalo Atomics raised $100 million. Heck, Radiant itself raised $165 million just six months ago.
Given the array of investments, it seems reasonable to wonder if the nuclear world is in a bubble. Technology investment has closely followed the data center boom. AI requires vast amounts of electricity, and technology companies and data center developers are scrambling to secure supplies from sources ranging from nuclear fission to supersonic jet engines.
As the power requirements of technology companies continue to increase, interest in nuclear is likely to remain strong. But there could be a field victory in the next year or two if the startups don’t keep their promises, many of which revolve around launching their first reactor next year.
Some startups may be able to buy some time after that. First-of-its-kind reactors can be built by hand, but many nuclear startups rely on the idea that mass production will make fission cost-competitive. They may succeed in reaching criticality, but they stumble when they try to replicate their designs.
None of this means that Radiant will fall into this category. may well succeed. Instead, the company happens to be the latest in a long list of nuclear startups that have announced eye-popping fundraisers in recent months. Whenever a market gets this frothy, the B word is bound to come up.
The new round was led by Draper Associates and Boost VC with participation from Ark Venture Fund, Chevron Technology Ventures, Friends & Family Capital, Founders Fund and others. Radiant is valued at over $1.8 billion. Previous investors include Andreessen Horowitz, DCVC, Giant Ventures and Union Square Ventures.
Radiant is developing a microreactor capable of generating 1 megawatt of electricity that can be delivered via semi. It will be cooled by helium and have enough TRISO fuel — graphite and uranium pellets coated with carbon and ceramics designed to be more resistant to meltdowns — to last five years between refuelings.
The startup aims to replace diesel generators in commercial and military installations. Customers will be able to buy the units outright or sign up to a power purchase agreement. When the reactor’s 20-year lifespan is over, the company will decommission it.
Like many nuclear startups, Radiant is targeting data centers as some of its first customers. The company signed a deal with data center developer Equinix in August to supply 20 of its reactors.
First, Radiant is building a demonstration reactor at the Idaho National Laboratory, which it hopes to begin testing in the summer of 2026. Many nuclear startups are on a similar timeline, one set by the Trump administration’s goal of three reactors achieving criticality — the time a nuclear reaction is self-sustaining — by July 4, 2026.
Radiant is one of 11 companies selected for this program, which does not provide government grants or loans but accelerates approval timelines.
Correction 1:20 p.m. ET: The Radiant’s reactor will be refueled once every five years, not months as previously reported.
