Throughout the 20th century, the societal attitude toward nuclear energy has been a complex and evolving narrative, seesawing between periods of bright-eyed optimism and well-founded skepticism. There was the Atoms for Peace initiative of the 1950s, followed by the strong anti-nuclear movement of the 70s and 80s shaped by the watershed moments at Three Mile Island and Chernobyl. With the looming threat of climate change, fears softened, and nuclear capacity expanded in the early 2000s—often referred to as the nuclear renaissance—before souring again in 2011 after the disaster at Fukushima.

Now, as the world moves toward a renewable energy future, the role of nuclear power hangs in the balance. This past April, Germany announced it was going cold turkey, shutting down its remaining nuclear plants that had been supplying electricity to more than one-quarter of German households. The decision didn’t come out of the blue—Germany planned for the complete closure of its nuclear reactors back in 2011. It’s a move decried by nuclear energy proponents as jeopardizing the country’s efforts toward its carbon-neutral climate targets.

Germany isn’t an isolated case. Since 2012, 12 nuclear reactors in the U.S. have permanently closed, with the most recent being New York’s Indian Point nuclear plant in 2021. According to a 2019 report by the International Energy Agency (IEA), 25 percent of “existing nuclear capacity in advanced economies [are] expected to be shut down by 2025.”

While it’s tempting to see this as nuclear energy’s swan song, some may argue it’s more like a phoenix rising from radioactive ashes. The industry is experiencing developments in next-generation reactors a fraction the size of massive power plants. There’s also considerable cash flowing in by the millions from federal and private investments into nuclear technology companies like Bill Gates’ TerraPower. And then there’s the heightened demand for energy security through nuclear energy brought on by Russia’s ongoing invasion of Ukraine.

So what does the future hold for nuclear energy in our world of mixed emotions? A lot of innovation, a fair bit of promise, but still many challenges and concerns to overcome.

It’s All About Downsizing

While new nuclear power plants in the U.S. are becoming scarce, there are two additional reactors being added to Georgia’s Plant Vogtle, which are expected to be operational by early 2024. However, the focus of the newest, fourth-generation nuclear efforts is on downsizing to achieve reactors more manageable and potentially more energy-needs bespoke, says Jess Gehin, associate laboratory director of nuclear science and technology at Idaho National Laboratory (INL), and John Jackson, national technical director of the Department of Energy’s Microreactor program also at the same institution.

“Around 20 to 30 years ago, we got interested in expanding the portfolio of [nuclear energy] options,” Jackson tells Popular Mechanics. “You can’t take a gigawatt-scale pressurized water reactor and plop it down in the middle of rural Alaska. So the idea was that we could improve the economy and the options by expanding into small modular reactors.”

Despite the name, small modular reactors (or SMRs) and their compact kin microreactors aren’t exactly pocket-sized. Jackson says SMRs weigh on the order of 20 tons and microreactors are about 100 to 1,000 times smaller than conventional nuclear reactors. The energy generated is significantly less but still impressive—anywhere from 50 to 300 megawatts, more than enough to power a small town or city. (For reference, conventional nuclear reactors make several gigawatts of energy by capturing the energy released when an atom splits, known as nuclear fission.)

A diagram of NuScale’s proposed small modular reactor.

NuScale Power

Unlike their nuclear progenitors, SMRs and microreactors are prefabricated units that can be delivered and assembled virtually anywhere, installed into an existing power grid or remotely off-grid, an approach offering potential cost and time savings compared to the construction of larger reactors.

The technology used is still the same with water or another substance like gas being used as a coolant or to moderate the nuclear reaction. The main difference, says Jackson, is that many SMRs and microreactors make use of passive safety features rather than active ones, which reduces the risk of accidents and minimizes the need for operator intervention. For example, instead of mechanically pumping coolant, some downsized nuclear reactors like NuScale’s SMR, whose design was approved by federal regulators in 2022, use natural convection for cooling.

But It’s Not All About Electricity

No doubt electricity is king in our modern world, but the future of nuclear energy goes beyond powering homes or having enough charge on your Steam Deck.

“People are now looking at what we call cogeneration,” Alireza Haghighat, professor of nuclear engineering and director of Virginia Tech’s Nuclear Engineering Program, tells Popular Mechanics.

Haghighat says this involves taking the surplus heat produced as a byproduct of nuclear fission and transferring it into other processes. This could be a district heating system where it’s used to provide space heating and hot water for residential, commercial, and industrial buildings in nearby communities. It could be industrial where high-temperature heat is needed for chemical manufacturing, food processing, or steam generation.

By combining electricity generation with heat utilization, cogeneration maximizes the energy efficiency and overall output of a nuclear power plant, explain Gehin of INL and Haghighat. It can significantly increase the overall efficiency of a nuclear plant by utilizing the heat that would otherwise be wasted, thereby reducing the environmental impact and improving the economics of the nuclear facility, potentially giving new life to those older plants.

Companies like the behemoth Dow Chemical have already made a move on cogeneration. In recent years, Dow Chemical partnered with X-energy, a U.S.-based private nuclear engineering company making gas-cooled reactors, to establish SMRs to heat and power one of its facilities along the Texas Gulf Coast by around 2030, Chemical and Engineering News reported last August.

Nuclear energy is also being considered to help produce clean hydrogen energy, an effort the Department of Energy has invested $20 million to figure out.

Perhaps an even more compelling reason for keeping nuclear energy close at hand is, surprisingly, renewable energy. Across the globe, renewables like solar, wind, and hydropower made up 29 percent of electricity generation in 2020, a trend expected to swell up even more by 2025, according to the IEA’s Electricity Market Report 2023.

But the problem with relying on renewable energy, says Jacopo Buongiorno, director of MIT’s Center for Advanced Nuclear Energy Systems, is that it’s unpredictable—at the capricious will of the environment—what’s called intermittent energy sources as opposed to baseload resources that run continuously for long periods of time.

Grid-scale battery storage is considered the answer to the intermittency problem, but it’s not without its challenges, such as designing batteries that can last long-term, the rising cost of lithium, and the costs of building super-sized storage facilities.

That’s why some energy experts like Gehin, Haghighat, and Buongiorno see nuclear not in competition with renewable energy but as a means of keeping it reliable and resilient, hopefully reducing the world’s dependence on fossil fuels and facilitating the transition to a sustainable and low-carbon future.

Nuclear energy could be used alongside other renewable energy sources, like solar, to make them more reliable.

Israel Sebastian//Getty Images

“Nuclear energy is not only carbon-free, just like wind and solar, but it’s dispatchable so it gives you the energy when you need it,” Buongiorno tells Popular Mechanics. “If you have a little bit of nuclear in your energy mix, you can reduce the amount of overbuilt renewables and storage that you need in order to meet demand.”

It’s important to note that while nuclear power plants themselves don’t directly produce greenhouse gasses, mining and refining uranium ore for reactor fuel may include some if fossil fuels are used in those processes or in the building of a plant.

The Persisting Challenges Ahead

Expanding nuclear energy across the world will have three things to contend with: cost, policies, and public perception.

While there’s no definitive answer as to who will dominate the nuclear market, SMRs and microreactors hold a fair stake. There are several private companies like NuScale, TerraPower, X-energy, and Elysium, and more established captains of industry like General Electrics and Westinghouse at various stages of reactor development and licensing. Jackson of the INL says we could expect SMRs and microreactors deployed as early as 2030 and as late as 2050. They likely won’t come cheap, at least not at first.

“It’s an uncertain number at this point since no one has built one,” he says. “But if you look around, you’ll find numbers in the vicinity of $100 million to build a microreactor. The key is, the first one might cost $150 million but the second one might cost $75 or 50 million. The economics improve with learning and [technology] evolution.”

Billions of dollars are already being spent to keep nuclear power plants alive with the Biden administration pledging $6 billion in November 2021 to maintain the existing nuclear fleet. Even more concessions were made with the Inflation Reduction Act passed last summer offering nuclear energy tax credits to existing plants.

While these legislative efforts aim to revitalize and incentivize the industry, more could be done by making climate change more legally binding on certain industrial sectors, Matt Bowen, a nuclear energy research scholar at Columbia University’s Center for Global Energy Policy, tells Popular Mechanics.

“There’s no binding policy to decarbonize the power sector, which is generally considered as the easiest sector to decarbonize,” says Bowen. “You have a few state clean energy standards, [and] you have a few non-binding utility pledges. Once you get outside the power sector, it’s really hard to decarbonize sectors like steel and concrete. There’s nothing forcing us to do that.”

Then there’s the issue of nuclear energy itself—the risk of nuclear weapons proliferation, associated health risks due to radioactive wastes and uranium mining, and meltdown risk. Tied closely to that is the public’s perception of nuclear energy, with infamous nuclear disasters like Three Mile Island, Chernobyl, and Fukushima remaining firmly in our social consciousness as cautionary tales.

Sukesh Aghara, director of the University of Massachusetts Lowell’s Integrated Nuclear Security and Safeguards Laboratory, believes the winds are shifting in favor of nuclear energy if Russia’s ongoing invasion of Ukraine is any indication. More and more countries don’t want to be dependent on Russian coal, gas, or oil supplies, and neither do they want to partner up with Russia’s state-owned nuclear energy industry given the country’s disregard for nuclear safety during the war.

“When you look at the global realignment, that’s why Poland and the Czech Republic signed [nuclear technology] agreements with the U.S.,” Aghara tells Popular Mechanics. “You have to look at the geopolitical alignments of countries… it’s a very clear indication of where they want to be at.”

Without a crystal ball, it’s hard to say whether the current interest in nuclear energy is sustainable or going through another one of its growing pains. There’s a hope that nuclear fusion—where energy is made from atoms coming together rather than splitting, which is considered relatively safer since it doesn’t produce long-lived radioactive waste—may usher in a new age of nuclear energy, although it’s still experimental.

Don’t be surprised, though, if one day you’ve got your own SMR sitting out in the backyard, fulfilling all your energy needs.

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Miriam Fauzia is a contributing writer at Popular Mechanics obsessed with all things energy. Her work has appeared in USA Today, The Daily Beast, and Inverse. When she’s not talking shop, she’s writing science fiction, reading too many comics, and chasing after way too many cats (her own, thankfully). 

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