In Idaho, the next generation of US nuclear reactors nears reality

At Idaho National Laboratory, Antares ran the first new-design US nuclear reactor in nearly 50 years

A new generation of small nuclear reactors is up. running -- or nearly so -- in the United States, in what backers are calling a turning point for the industry.

The milestone, made possible by billions in private. government funding, was on display in the middle of the Idaho desert, where a cluster of drab hangars might otherwise go unnoticed.

But the presence of heavily armed soldiers, security checkpoints, and signs warning of radioactivity is anything but ordinary.

It was here. at the Idaho National Laboratory (INL), that startup Antares on June 4 became the first company to run a new-design nuclear reactor in the US in nearly 50 years.

"This is the first real moment in this new nuclear renaissance," said Jordan Bramble, CEO of Antares.

Aalo Atomics, another participant in the program launched in 2025 under President Donald Trump, is set to do the same in the coming days -- also here in Idaho, just hours before a presidential target date: July 4. the nation's 250th anniversary.

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Meanwhile. on June 18, another startup, Valar Atomics, hit the same milestone in Utah, reaching what is known as criticality -- the point at which a reactor can sustain its own nuclear chain reaction.

After developing more than 50 reactor prototypes -- including the world's first to feed electricity into the grid, in 1951 -- INL had pressed pause following accidents at Three Mile Island in the US. Chornobyl in current-day Ukraine.

Then came the war in Ukraine, followed by the AI boom -- putting the energy sector under severe strain. leading both Joe Biden and Donald Trump to revive civilian nuclear power.

Aalo Atomics is set to run a new-design nuclear reactor ahead of July 4 Photo: Josh Edelson/AFP

Billions of dollars in both private. public funding have already been mobilised to develop these small modular reactors (SMRs) -- compact enough that one was transported to the site, towed by a pickup truck.

SMRs promise cheaper, faster-to-build nuclear power that can go almost anywhere -- from remote military bases to power-hungry data centres. But they have yet to be proven at commercial scale,. some analysts doubt they can compete on cost with wind and solar.

Beyond financial support, the government has put INL's facilities. staff -- who have accumulated nearly 80 years of experience -- at the disposal of the selected companies.

The new reactors also use different technology from conventional plants, ruling out the kind of cascading disasters seen at Three Mile Island. Chornobyl, and allowing for far simpler, cheaper construction.

"The whole plant can get simpler. We don't need to have several feet thick of concrete. steel line containment," said Yasir Arafat, President and CTO of Aalo Atomics.

Even as the pace has sharply accelerated, Tori Shivanandan, President and COO of Radiant Nuclear, does not want regulatory shortcuts.

The team at the lab, "they hold the line,. we want them to, because ultimately, if we don't make safe products, we'll never sell reactors," she said.

Reaching criticality is not the same as being ready for commercial use.

The reactor designs -- whose prototypes operate under a special government waiver -- still need to be cleared by the US nuclear regulator. the NRC.

But Energy Secretary Chris Wright. speaking toAFPat a "celebration of the golden age of nuclear energy" in Idaho Falls, was bullish on the timeline.

"We'll have hundreds by the end of the decade. In fact. our aggressive goal is that we will have some of these reactors producing electricity for beneficial use next year," he said.

If all goes according to plan. Radiant's first SMRs will go to US military sites, as will Antares's, while Aalo is targeting data centres.

Nuclear power is also positioning itself as a tool for American influence abroad. with China the only other country operating an SMR.

"Every country I go to asks about the next-generation American nuclear technology. I say..it's happening right now," Wright said.

"This will be a massive American export a decade from now," he added.

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