Another day, another nine-figure round for a nuclear launch.

Bright Nuclear now says it has raised more than $300 million, only one day after Last Energy said it had raised $100 million. Three weeks agoX-energy raised $700 million, and in AugustAalo Atomics raised $100 million. Heck, Radiant itself raised $165 million just six months ago.

Given the range of investments, it seems reasonable to ask if the nuclear world is in a bubble. Technology investment has closely tracked the data center boom. AI requires large amounts of electricity, and tech companies and data center developers are rushing to obtain supplies from sources ranging from nuclear fission to supersonic jet engines.

As long as tech companies’ power needs continue to grow, interest in nuclear is likely to remain strong. But there could be a shutdown in the field in the next year or two if the startups don’t keep their promises, many of which revolve around starting their first reactor next year.

Some startups may buy a few hours after that. First-of-a-kind reactors can be built by hand, but many nuclear startups are based on the idea that mass manufacturing will make fission cost-competitive. They may succeed in achieving criticality but stumble when they try to replicate their designs.

This is not to say that the Radiant falls into that category; it can be very successful. Instead, the company happens to be the latest in a long list of nuclear startups that have announced funding in the past few months. Whenever a market gets such a bubble, the B-word is bound to pop up.

The new round was led by Draper Associates and Boost VC with participation from Ark Venture Fund, Chevron Technology Ventures, Friends and Family Capital, Founders Fund, and others. This values ​​Radiant at more than $1.8 billion. Previous investors include Andreessen Horowitz, DCVC, Giant Ventures, and Union Square Ventures.

Radiant is developing a microreactor that can produce 1 megawatt of electricity that can be delivered via semi. It will be cooled with helium and have enough TRISO fuel — carbon — and ceramic-coated beads of graphite and uranium designed to be more resistant to meltdowns — to last five months between refueling.

The startup aims to replace diesel generators in commercial and military areas. Customers can purchase units directly or subscribe to a power purchase agreement. When the reactor’s 20-year life is up, the company will take it down.

Like many nuclear startups, Radiant targeted data centers as some of its first customers. The company signed an agreement with data center developer Equinix in August to supply 20 of its reactors.

First, Radiant built a demonstration reactor at the Idaho National Lab, which hopes to start 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 that reach criticality – the moment when a nuclear reaction is self-sustaining – on July 4, 2026.

Radiant is one of 11 companies selected for that program, which does not provide government grants or loans but has accelerated approval timelines.