Small Modular Reactors

Gregory Chassapis
May 8
4 min read

On December 2, 1942, beneath the bleachers of a squash court at the University of Chicago, a team of scientists led by Enrico Fermi carefully withdrew a set of cadmium control rods from a lattice of uranium and graphite blocks. The instruments confirmed what Fermi already suspected: a self-sustaining nuclear chain reaction was underway. There was no explosion, no flash of light- just the quiet clicking of Geiger counters accelerating into a steady hum.

The atomic age had begun and the future it promised seemed limitless.

Within two decades, nuclear power had evolved from a wartime secret into a civilian energy revolution. Eisenhower’s “Atoms for Peace” speech reframed it as humanity’s ticket to abundant, cheap electricity, and by the 1970s, reactors were sprouting across the industrialized world.

And then, it stalled. Three Mile Island. Chernobyl. Fukushima. Each disaster deepened public fear, tightened regulation, and inflated costs. The seemingly inevitable nuclear future, simply stopped.

Why Traditional Nuclear Stalled

There’s no mistaking the fact that nuclear power is an extraordinary technology. A single uranium fuel pellet contains as much energy as a ton of coal, plants produce virtually zero carbon emissions during operation, and nuclear remains the largest source of clean energy in the United States at approximately 20% of the total output.

At its core, the problem is cost and complexity. Traditional reactors are enormous, bespoke construction projects that take over a decade and routinely exceed $10 billion per unit. The two newest reactors in the U.S., for example, Vogtle Units 3 and 4 in Georgia, came online seven years behind schedule and roughly $17 billion over budget.

Then there is regulation. The Nuclear Regulatory Commission (NRC) licensing process can take five to ten years and cost hundreds of millions of dollars before a single shovel hits the ground. Public perception, meanwhile, proved nuclear’s most stubborn adversary. Despite having one of the lowest mortality rates of any energy source, nuclear power remains uniquely feared. With ballooning budgets, glacial timelines, and a skeptical public, the Western nuclear industry effectively entered a long winter.

Enter the Small Modular Reactor

Unlike their larger counterparts, Small Modular Reactors, or SMRs, are designed to be compact (generally 300 megawatts or less), factory-fabricated in modular components, and shipped to a site for assembly. The result is shorter build times, lower upfront capital costs, and the ability to scale capacity incrementally by adding modules as demand grows. Many designs also incorporate passive safety systems that rely on natural physics such as gravity, convection and natural circulation to cool the reactor in an emergency without requiring external power or human intervention.

The regulatory landscape is also starting to shift.

In January 2023, NuScale Power became the first company to receive full NRC design certification for an SMR. In May 2025, the NRC approved NuScale’s uprated 77-megawatt design ahead of schedule. TerraPower’s Natrium reactor has received construction permits, and X-energy’s Xe-100 reactor is expected to receive them by early next year. At the same time, the DOE’s pilot reactor program is targeting first criticality (i.e. the moment a reactor achieves a self-sustaining nuclear chain reaction) for experimental reactors by mid-2026, underscoring the accelerating pace of deployment across the sector.

Capital has responded.

Amazon has partnered with X-energy to deploy over 5 gigawatts of SMR capacity. Google backed Kairos Power. Venture Capital and Private Equity have also gotten in on the action, with over $5B invested across early and mid-stage private companies. Of that total, over $1.5B came in 2025 alone, and that doesn't include the $900 million or so in government support.

Far from speculative bets, they are strategic investments in 24/7 baseload power that can be sited directly adjacent to the facilities that need it most.

And while this is all good news, challenges persist.

To date, no commercial SMR operates in the U.S. (though a number are currently under construction). NuScale’s earlier Idaho project was cancelled in late 2023 as costs rose and customer interest waned. Building factory-scale supply chains demands enormous upfront capital. And while regulatory timelines have improved, they remain long relative to the urgency of the market.

The Future

The next five to ten years will determine whether SMRs become a transformative pillar of the global energy stack, but the good news is that the signals are more encouraging than they have ever been. Over 10 gigawatts in committed nuclear deals from Big Tech, hundreds of millions in federal funding, bipartisan political support, and more than 100 SMR designs in development worldwide.

For investors, the thesis is straightforward: the world needs dramatically more clean, firm baseload power, and it needs it soon. Wind and solar are intermittent. Natural gas carries emissions and price volatility. SMRs offer a scalable, zero-emission, always-on energy source that can complement renewables and serve applications that other clean sources simply cannot. The companies that successfully commercialize this technology will be positioned at the center of the 21st century’s energy transition.

Fermi’s squash court experiment will always be remembered as a pivotal moment that kickstarted the atomic age, but it is up to this generation of builders, investors, and policymakers to solidify it as the the foundation for what is still to come.

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