A New Era of Nuclear Power

Welcome to Dispatch Energy! While the headlines focus on UFC fights on the White House’s South Lawn and botched renovations of the Lincoln Memorial Reflecting Pool, the Trump administration is marking America’s upcoming semiquincentennial with a quieter but much more significant milestone: achieving “criticality” with advanced nuclear reactor prototypes.  

Last year, the Trump administration created the Reactor Pilot Program, a Department of Energy project to enable the prototyping of next-generation nuclear reactor designs. The administration’s stated goal was to achieve “criticality” with three advanced reactors by July 4, 2026. And in the last month, two reactors authorized under the program—Antares Nuclear’s Mark-0 sodium-cooled microreactor and Valar Atomics’ Ward-250 high-temperature gas reactor—went critical.

A reactor goes “critical” when the nuclear fuel inside it achieves a self-sustaining fission chain reaction—meaning that, on average, each fission event triggers one more fission event, allowing the reactor to produce energy continuously. Of course, that’s not all that’s required to actually sustain this process: A commercial nuclear power plant requires containment vessels, coolant to modulate the reaction, turbines to convert the energy into electricity, control rooms, spent fuel management, and more. But a critical nuclear reaction in the plant’s core is what makes the whole operation work.

All commercial nuclear plants in the United States today use low-enriched uranium as nuclear fuel and light water (regular water) as coolant. What the Trump administration is doing via the Reactor Pilot Program is demonstrating the technical viability of a new generation of advanced reactor designs with different fuels and fuel cycles, different coolants, and other innovative characteristics. Some are designed to produce hydrogen or high-temperature heat for industrial processes in addition to generating electricity, while others are intended for propulsion. All of the reactors under consideration for the program are also smaller, in some cases much smaller, on a power-output basis than conventional nuclear plants.

When I wrote about the Reactor Pilot Program for Dispatch Energy in November, I described it as “the latest development in a technological, regulatory, and commercial transformation of the American nuclear industry.” 

This is a first step—literally the prototype phase—of a long process of innovation that will hopefully culminate in fully commercialized next-generation nuclear reactors producing abundant electricity on power grids around the world. But it’s a meaningful milestone nevertheless, for an industry rediscovering itself after decades of relative decline, and for an administration that has placed a conspicuous bet on nuclear power in particular.

At the level of engineering, there are reasons to think that nuclear power should generate the cheapest electricity available. As research by my organization, the Breakthrough Institute, has illustrated, nuclear power plants have the smallest land footprint and require the least physical material on a life-cycle basis of any energy technology. 

But instead, building nuclear plants became increasingly expensive over the decades. My fellow Dispatch Energy contributor Roger Pielke Jr. recently published a three-part history of the United States’ commercial nuclear power development, almost all of which occurred between the 1950s and the 1980s. As Pielke explains, the promising, epochal energy technology eventually ran aground against overregulation, environmentalist opposition, and industrial mismanagement.

Meanwhile, energy technologies like solar panels, natural gas turbines, and electric vehicles have plummeted in price in recent decades due to the modularity of their design, as well as the development of mature, experienced workforces and supply chains. There are thousands of natural gas and solar power plants, and millions of electric cars, in the U.S. By contrast, there are only 57 operating commercial nuclear plants in the whole country. Again, this is a feat of technological efficiency: Just those 57 plants generate fully 20 percent of the nation’s total electricity supply. But each of them was effectively built as a one-off megaproject, with bespoke design, planning, engineering, construction, and even regulation. 

The megaproject approach to nuclear power drove costs up significantly over the decades. Electric power utilities mitigated this effect by developing ever-larger reactors, so each plant would produce more electricity, and by gradually ratcheting up existing plants’ “capacity factor,” the portion of the year the reactor spends actually generating electricity. America’s nuclear plants have an average power capacity of 1,800 megawatts and an average capacity factor of 92 percent, while most natural gas plants put out less than 500 megawatts of power with an average capacity factor of 40 to 60 percent. (The figures for solar and wind power are even lower.) 

Large reactors, small land and material footprints, and high output allow the nation’s nuclear plants to generate reliable and affordable electricity. But even so, it has become prohibitively expensive to build new ones. The only commercial nuclear plant to be fully developed in the United States over the last 20 years, the Vogtle plant in Georgia, ran more than seven years behind schedule and ultimately cost more than $30 billion, more than double the $14 billion initial estimate. Vogtle was supposed to be the vanguard of a “nuclear renaissance.” Instead, since Vogtle, U.S. electric utilities have been almost completely uninterested in new nuclear development. 

That is, until recently. In the last few years, three developments have changed the calculus for nuclear power in the United States. 

The first is a sea change in how investors and policymakers understand the technology. While the first generation of commercial nuclear plants was developed in the shadow of the Cold War and the incipient anti-nuclear environmental movement, today’s more climate-conscious decision-makers understand nuclear energy as an advanced energy technology that produces no pollution or carbon emissions. Nuclear power is increasingly popular across the political spectrum and, indeed, is the only energy technology that is actually growing in popularity today.

The second is the rise in electric power demand currently underway in the United States. Overall U.S. power generation has been stagnant since the 1990s, as the American economy has shifted toward less power-intensive knowledge and service work. But with the construction of AI data centers, the electrification of vehicles, and other forms of consumer demand, American electricity consumption is rising for the first time in a generation. All that new power has to come from somewhere.

Which brings us to the third recent development: the emergence of a new class of nuclear reactor. While some new electric demand is being met by restarting old, shuttered nuclear plants like Three Mile Island in Pennsylvania and Palisades in Michigan, many utilities and tech companies have their eyes on this new generation of smaller, advanced reactors like those being developed by Valar, Antares, Kairos, Oklo, X-Energy, and Terrapower. 

The promise of these new reactor designs is that they can achieve the kind of modularity that natural gas and solar plants benefit from. While the reactors at the Vogtle plant discussed above are each rated at more than 1,000 megawatts, the Valar and Antares prototypes that recently achieved criticality are designed for reactors generating 5 megawatts or less. Reactors of this size should prove much easier to manufacture and deploy in multiples, hopefully generating technological learning, workforce development, and other industrial engineering processes that make technology cheaper over time. 

These “microreactors” are also more amenable to the type of prototyping the Reactor Pilot Program was designed to achieve. The early-stage demonstration reactors will yield essential performance data, allowing engineers and developers to iterate on design all the way through to the commercial reactor projects.

When the program was announced last June, some media outlets voiced skepticism over whether the July 4 deadline would be met. Some skepticism is fair: It came from decades of delays and disappointments in nuclear project development.

Likewise, many of the usual antinuclear suspects expressed outright opposition to the program’s goals, with the Union of Concerned Scientists’ Edwin Lyman calling it “an attempt to subvert the laws and regulations that go around commercial nuclear power.”

But America’s semiquincentennial is right around the corner, and two of three reactors have indeed gone critical. And they have done so not because policymakers have “subverted” nuclear law and regulation, but because they have reformed it. Over the past 10 years, Congress, the Trump and Biden administrations, and the Nuclear Regulatory Commission have all enacted a transformation in nuclear regulatory and commercialization policy. Federal policymakers have created new licensing pathways for advanced designs, funded new demonstration facilities at national laboratories, and created new commercial incentives for nuclear power. 

And it’s not just these demonstration prototypes. The startups Terrapower and Kairos Power have broken ground on advanced reactor projects that, if completed, will generate commercial electricity. The national Energy Dominance Financing office is also exploring loan guarantees to more conventional large light-water reactor projects. 

All of this policy action may not be enough to realize a true nuclear renaissance in the coming decades. Science, engineering, markets, geopolitics, and public opinion all need to be navigated as well. But many of the pieces are in place for what my colleague Ted Nordhaus recently called “the most ambitious effort to commercialize new nuclear energy technology since the Eisenhower administration’s Atoms for Peace initiative.”

Much policy and technological uncertainty remains ahead for nuclear advocates and innovators. But we should pause and celebrate this milestone—not just for its technical achievement, but for its place in a long line of American innovations.