To feed artificial intelligence’s insatiable energy appetite, high-tech companies are actively working on the development of small nuclear reactors.
Last week, both Google and Amazon announced deals with companies developing small modular nuclear reactors. These reactors have lower power output than current nuclear reactors, and many designs include different types of fuel or coolant, as well as additional safety features.
This announcement further amplified the buzz around small modular nuclear reactors, which have been attracting increasing attention in recent years given the need for clean energy that does not contribute to climate change. Various companies have sprung up to meet this need, creating a treasure trove of proposed designs for small modular reactors.
“If you combine the need for resilient power with the need for clean power and the availability of these designs,” said Kathryn Huff, a nuclear engineer at the University of Illinois at Urbana-Champaign, “There will be a significant increase in interest.”
Meanwhile, the U.S. government is supporting the development of small modular nuclear reactors, further increasing interest.
So what’s in store for this new nuclear power opportunity? We unravel the big questions: how and why nuclear reactors are becoming smaller.
What is a small modular reactor?
Commercial nuclear reactors in the United States typically produce about 1 billion watts of electricity. Small modular reactors would produce less than a third of that.
Traditional nuclear power plants require large upfront investments, hurdles that have hindered the construction of new nuclear reactors in the United States for decades. The nation’s first new nuclear reactors in 30 years (two in Waynesboro, Georgia, scheduled to come online in 2023 and 2024) cost about $30 billion. Construction was years behind schedule and billions of dollars over budget.
By pivoting to small nuclear reactors, companies and policymakers are aiming to popularize nuclear power, which is touted as a reliable source of energy that does not emit greenhouse gases.
Additionally, smaller reactors generate less electricity, which simplifies safety systems by requiring less residual heat to be removed to safely shut down the reactor in the event of an accident.
If the reactor is small, Huff said, it’s easier to assemble parts off-site at the factory and transport them to where they’re needed, rather than custom-assemble the parts from raw materials on-site. “The more these reactors can be built like airplanes and not airports, the cheaper it will generally be.”
What is driving the interest in these reactors?
Nuclear power currently enjoys support from both Democrats and Republicans in the United States, an unusual situation that allows the sector to thrive even as political power changes. “We’ve seen pretty consistent growth in support over the last 10 years, and I think that’s a big deal,” said Todd Allen, a nuclear engineer at the University of Michigan. Nuclear energy is a pillar of the Biden administration’s plan to meet climate change goals.
Meanwhile, AI’s insatiable demand for energy poses problems for tech companies that don’t want to be seen as climate change villains (SN: 12/11/23). Google announced on October 14 that it will purchase energy from small modular nuclear reactors it is building. kairos poweraims to have the reactor operational in the 2030s. And on October 16, Amazon announced: investment in Agreed with X-energy to establish small modular nuclear reactors with utilities in Virginia and Washington.
And it’s not just big tech companies that are interested. a 2023 agreement X-energy and chemical company Dow have announced that they will build a small modular reactor at one of Dow’s locations.
The US Department of Energy is funding the development of small modular nuclear reactors. The Department of Energy announced on October 16th. $900 million in funding For deployment of small modular nuclear reactors. And both X-energy and Bill Gates-backed TerraPower are building demonstration projects with support from the DOE.
Traditional nuclear power plants will still have a role for the foreseeable future. On September 20, Microsoft announced a deal to restart the Three Mile Island power plant near Middletown, Pennsylvania, which shut down in 2019. that Three Mile Island. After the infamous partial meltdown in 1979, another reactor at the power plant continued to operate (SN: 79/4/7). )
“Companies that have traditionally avoided mentioning nuclear energy as part of their portfolio due to concerns about public perception and potential policy backlash are coming forward and actively adopting nuclear energy. “Yes,” says Kološ Silvan, a nuclear engineer at the Massachusetts Institute of Technology.
How is this technology different from current nuclear reactors?
Commercial nuclear reactors in the United States typically use the same type of uranium fuel and are cooled with water. However, many small modular reactor designs are breaking the mold.
The uranium used in nuclear reactors is enriched to contain more of a related type of uranium, the isotope U-235. Current nuclear reactors use uranium enriched to a few percent U-235. Many small modular reactors use U-235 enriched up to 20 percent, known as High Analysis Low Enriched Uranium, or HALEU.SN: 7/3/24). This fuel allows small modular nuclear reactors to operate more efficiently than reactors using conventional fuels. Although the United States does not commercially produce large quantities of HALEU, efforts are beginning to pick up steam in anticipation of the need.
Some nuclear reactors use different fuels in more obvious ways. For example, X-energy and Kairos will use TRISO fuel. TRISO fuel is encapsulated poppyseed-sized uranium pellets, each contained within a larger sphere of material about the size of a tennis ball. The fuel is “very resistant to very high temperatures for very long periods of time,” Hough said. “This gives you an extra layer of protection.”
The coolant, the medium used to transfer heat from the reactor to the power-generating portion of the plant, is an equally important choice. TerraPower uses liquid sodium, Kairos uses molten fluoride salt, and X-Energy uses helium gas. Different coolants have advantages such as improved heat transfer efficiency and elimination of the need for pressurized vessels.
The design also includes safety features that do not require human intervention, allowing the reactor to be safely shut down in an emergency. For example, gravity, pressure differences, and natural convection of the coolant are used to cool the reactor core.
What’s next?
The concept of small modular nuclear reactors has existed for many years, but previous attempts have been unsuccessful. I am also having trouble with my recent efforts. Nuclear reactor company NuScale was scheduled to produce the first commercially available small modular nuclear reactor as part of a project in Idaho, but the project was canceled in 2023 due to rising costs.
Now, with big tech companies getting into the business, proponents are hopeful that small modular reactors will soon take off.
“We’re seeing momentum building,” Allen said. “It doesn’t mean we’re going to see a new commercial version this year, but it also means there’s a lot more real life going on than we’ve seen with nuclear power for a long time.”
