Oak Ridge, Tennessee (USA) — A former home of the Manhattan Project, the fields surrounded by wooded valleys and rolling hills in Oak Ridge, Tennessee (USA) may soon spawn yet another nuclear innovation.
Foundations and concrete piles are being erected here for what is expected to be one of the first representatives of a new generation of nuclear power plants, known as small modular reactors. The company behind the project, Kairos Energy, has been developing its technology for almost a decade and is now deep into the construction phase.
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Many companies are racing to build reactors that experts say could, over time, be cheaper than the large nuclear complexes used for decades.
According to executives and government officials, the world would be at the dawn of a new nuclear era, which would provide cheap energy and meet the gigantic electricity appetite of artificial intelligence technology.
At the heart of that promise is the idea of reducing the size of the vessels where nuclear reactions heat water to produce the steam that turns turbines.
The logic is that the components of these smaller reactors can be mass-produced and assembled more easily than conventional designs, made by veritable armies of highly skilled workers.
The nuclear power industry has long struggled to complete projects. Nearly all operating nuclear plants in the United States began generating power decades ago, most even before Bill Clinton became president.
In recent decades, high costs and long delays, coupled with safety concerns, have slowed the advance of nuclear energy.
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“I think a lot of people recognize the value of what nuclear power can offer, but are still a little nervous about whether it can actually be delivered,” said Mike Laufer, co-founder and CEO of Kairos Energy, based in the San Francisco Bay Area. “Credibility can be very difficult to gain, but it can be lost very quickly.”
The United States has more nuclear reactors than any other country, but lags far behind in building new ones.
Over the past decade, China has built more than three dozen reactors, while the United States has completed just two. These two, at the Alvin W. Vogtle plant near Augusta, Georgia, were completed years late and cost $35 billion—about three times the original estimate.
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President Donald Trump wants new reactors to be a hallmark of his administration. His Department of Energy has committed $800 million to new reactor technologies and $1 billion in loan guarantees to restart the Three Mile Island plant in Pennsylvania. The government must offer billions more.
The race to reduce costs
Nine years ago, the three founders of Kairos Energy began developing their projects, focusing on a new approach. The three studied nuclear and mechanical engineering at the University of California at Berkeley, where J. Robert Oppenheimer, leader of the Manhattan Project, once taught.
Kairos executives said they decided to test each phase of the plant’s development as it went along, rather than following the more common practice in this industry: design, build and hope it works.
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Unlike conventional nuclear plants, the Kairos reactor will not have large domed concrete and metal structures. And there will be no plumes of steam rising from huge cooling towers. Instead of water, the Kairos reactor will heat salt.
The reactor will be just over 10 meters tall. The complete commercial project includes two reactor buildings and a turbine, occupying a total area of 243 thousand square meters.
The company, which has 540 full-time employees, designs and manufactures its own components. Many pieces are produced in Albuquerque, New Mexico, about 100 kilometers from Los Alamos, the definitive headquarters of the Manhattan Project.
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Nuclear projects have been hampered by high costs and the difficulty of building something new, Laufer said. “And recent experiences have only reinforced this.”
NuScale, a company once touted as the first to deliver a small reactor, had to cancel a project in Idaho in November 2023 after utilities pulled out of buying its power because costs had risen too much.
The company said its technology is now advancing through a partnership with ENTRA1 Energy, a plant owner and developer. In September, the two companies and the federally owned Tennessee Valley Authority announced plans to develop nuclear reactors.
NuScale’s first units will be built in Oak Ridge and could provide power until 2030, the company said.
Other companies are pursuing similar projects.
GE Vernova Hitachi Nuclear Energy has plans to build several smaller reactors starting in Ontario. TerraPower, a company backed by Bill Gates, is building a reactor in Wyoming.
Radiant Energy Group, a startup, says it is ready to build a portable microreactor this year capable of generating enough electricity to power 1,000 homes. These devices serve special uses, such as providing power to data centers or the military sector.
“If you don’t need a network connection, we’re a great solution,” said Ray Wert, company spokesman.
Like Kairos, Radiant plans to manufacture its reactors in Oak Ridge, home of Oak Ridge National Laboratory, one of the Department of Energy’s 17 national laboratories.
Big supporters and new fuel
In Oak Ridge, Kairos is working on a test reactor that should be ready in 2028; A demonstration unit, capable of producing electricity, is planned for 2030.
The company has a contract to supply 500 megawatts of capacity — about half that of a traditional large nuclear plant — to Google by 2035.
Google’s participation can make a huge difference. Tech companies investing in AI bring in money and interest that was lacking in the early 2000s, when delays and exploding costs thwarted ambitions for a “nuclear renaissance.”
The reactors being built by Kairos and other companies will use something called isotropic tristructural particulate fuel, or Triso, developed by the Department of Energy. Triso particles are enriched uranium cores coated with multiple layers of carbon and ceramic.
Thousands of these particles, the size of a poppy seed, are embedded in a graphite matrix to form spheres the size of golf balls.
The Triso layer contains the radioactive material from uranium as it decays and generates heat. With this containment system built into the fuel and molten salt cooling, these reactors would not need the same reinforced containment structures used in conventional plants, their supporters say.
But some scientists are not convinced that this new fuel eliminates all safety concerns. Edwin Lyman, a physicist and director of nuclear safety at the Union of Concerned Scientists, said Triso particles can generate very high heat, which would justify the use of containment structures.
“In my view, the promises made about Triso are greatly exaggerated,” Lyman said. “We are really heading towards a very dangerous experiment on the American population.”
But other experts are less concerned about the new fuel and new reactor designs.
Charles Oppenheimer, grandson of J. Robert Oppenheimer, is the founder and CEO of Oppenheimer Energy, a developer of nuclear projects.
He said he was discussing a possible role as an advisor on plans to revive VC Summer, a large, traditional nuclear project in South Carolina that was canceled in 2017 after $9 billion had already been spent.
Oppenheimer also said he was optimistic about the Kairos project, in which he is not involved. “They have been executing very well,” he said. “Others that make more noise aren’t building as much. In this game, nothing counts until the plant is running.”
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