Mockup of a the top third of a small module reactor made by NuScale, the only SMR developer with a design approved by the U.S. Nuclear Regulatory Commission.

Opinion: The Big Problem With Small Nuclear Reactors

The diminutive reactors are likely to be just as prone to delays and cost overruns as their behemoth predecessors.


In recent years, the nuclear power lobby and its advocates have begun to sing a new song. They have bailed on the monstrous reactors of the 20th century — not because of safety or toxic waste concerns, but because of the reactors’ exorbitant expense and ponderous rollout schedules. And they have switched their allegiance to a next generation nuclear fission technology: small modular reactors, which they claim will help rescue our warming planet, as well as the nuclear power industry— once they exist.

Respected thinkers such as former U.S. president Barack Obama, French president Emmanuel Macron, and Microsoft co-founder and philanthropist Bill Gates have toasted the idea of small modular reactors, or SMRs, as a potentially reliable, almost-emissions-free backup to intermittent renewable energy sources like wind and solar. Advocates claim that because SMRs will be smaller than the giants that currently dominate horizons, they will be safer, cheaper, and quicker to build. Although SMRs will have only a fraction of the power-generating capacity of traditional nuclear power reactors, proponents envision that they will, one day, be assembled in factories and transported as a unit to sites — like Sears’ mail-order Modern Homes of the early 1900s.

Currently, half of the states in the EU, both major political parties in the U.S, and the five BRICS nations — Brazil, Russia, India, China, and South Africa — have indicated that they want to split atoms for the purpose of generating energy. U.S. President Joe Biden included billions of dollars in tax credits for nuclear energy in the Inflation Reduction Act and the Infrastructure Investment and Jobs Act. Gates has gone so far as to invest a chunk of his fortune in a firm he founded, TerraPower, a leading nuclear innovation company. But despite the prodigious chatter, the endeavor to blanket the Earth with SMRs is a Hail Mary pass that’s very unlikely to succeed.

Granted, it is certainly a step in the right direction that most observers now see the postwar, giga-watt-scale water-cooled reactors as obsolete. When constructed new, these behemoths generate electricity at up to nine times the cost of large-scale solar and onshore wind facilities, and can take well over a decade to get up and running. Perhaps for this reason, there has been one, and only one, new nuclear power project initiated in the U.S. since construction began on the last one 50 years ago: a two-reactor expansion of the Vogtle Electric Generating Plant in Georgia. The first of the reactors came online this yearseven years behind schedule. The staggering $35 billion cost for the pair is more than twice the original projection.

But SMRs are just as likely to face similar delays and cost overruns. Currently, there are just two existing advanced SMR facilities in the world that could be reasonably described as SMRs: a pilot reactor in China and Russia’s diminutive Akademik Lomonosov. More small reactors are under construction in China, Russia, and Argentina, but all of them are proving even more expensive per kilowatt than traditional reactors.

It’s worth noting that in the U.S., and everywhere else in the world, nuclear policy relies heavily on subsidies to be economically competitive. Starting next year, utilities operating nuclear facilities in the U.S. can qualify for a tax credit of $15 per megawatt-hour — a break that could be worth up to $30 billion for the industry as a whole. However, even these giveaways won’t reduce the projected costs of SMR-generated electricity to anywhere near the going prices of wind and solar power.

In the U.S., the only SMR developer with a design approved by the Nuclear Regulatory Commission is NuScale, which plans to deploy six modules at one site in Idaho that will together generate less electricity than a smallish standard nuclear reactor. So far, however, NuScale has yet to lay a single brick. Its biggest win to date is securing $4 billion in federal tax subsidies. In January of this year, NuScale announced plans to sell electricity not at $58 per megawatt-hour, as originally pledged, but at $89 per megawatt-hour, citing higher than anticipated construction costs. The new projection is nearly twice the average global cost of utility-scale solar and onshore wind, according to calculations by BloombergNEF. And without the government subsidies, NuScale’s price tag would be that much higher.

In fact, there’s a fair chance that not a single NuScale SMR will ever be built: The company has said it will not begin construction until 80 percent of its expected generation capacity is subscribed, and currently buyers have signed up for less than a quarter of the plant’s capacity.

Gates’s TerraPower has an even longer way to go, although it too is cashing in on subsidies. The U.S. Department of Energy has pledged up to $2 billion in matching funds to construct a demonstration plant in Wyoming. Yet TerraPower recently announced it’s facing delays of at least two years because of difficulties securing uranium fuel from its lone supplier: Russia.

Even if the unlikely rollout of SMRs eventually happens, it will unfold too late to curb the climate crisis.

Even if the unlikely rollout of SMRs eventually happens, it will unfold too late to curb the climate crisis. And the reactors will face many of the same safety and radioactive waste concerns that plagued their larger counterparts, if only at smaller scales. Meanwhile, the siren song of nuclear energy is diverting critical resources from the urgent task of building out clean technologies. And the idea that nuclear reactors would serve as “backups” for wind and solar is misguided because the reactors can’t be ramped up and down quickly.

One is left to wonder why it is that intelligent people like Gates and Obama are running down this rabbit hole?

I think it’s because they understand the chilling imperative of the climate crisis, and its scope. They’re panicked, and rightly so. In nuclear energy, they see a miracle-like, low-carbon power source that they know, and that can serve a million customers at a time. Despite plenty of evidence to the contrary, they don’t trust renewables and smart energy systems to get the job done.

But that is where they err. The technology of the future is already here. Clean wind and solar energy — coupled with updated smart grids, expanded storage capacity, hydrogen technology, virtual power plants, and demand response strategies — can work. Our energy systems of the future will look like a patchwork quilt, with diverse energy sources kicking in at different times during the day, and with the mix differing from one day to the next.

Bill Gates and like-minded innovators should put their minds and fortunes to work on this futuristic project of the present — and leave the 20th century relic that is nuclear power in the past, where it belongs.

Paul Hockenos is a Berlin-based writer who covers energy and climate topics.