The Meltdown--Oops, We Mean Rundown--on Nuclear

Welcome back to Climatific, a free, weekly read that breaks down climate science so it makes sense- not for scientists or researchers, but for everyday people trying to understand the planet we live on, what’s happening to it, and why it matters.

Today’s issue discusses clean energy’s most controversial ally - nuclear generation.

Everybody’s got thoughts on nuclear. Some think it’s the future of energy generation in the US and beyond. Others think the risks of a meltdown aren’t worth the payout or they’re concerned about shooting radioactive waste back into the Earth. The rest of us are thinking, ‘What even is nuclear?’

Lucky for you, this issue will address all these… in reverse order. Join us as we explain how nuclear works and a bit about why the public’s perception of and support for nuclear is as scattered as the atoms that bounce around in a nuclear reactor.

If you learn something today, share this issue with someone you know! Better yet, encourage them to subscribe here:

Wait, wait, wait! It’s not quite as scary as you think… The simplest way I can describe it (liable to upset any scientists reading this) is that nuclear energy is just a very unusual way of boiling water.

How it Works. Nuclear energy is made when atoms, typically of the element uranium, are split apart in a process called “fission.” This process releases an enormous burst of heat, which boils water, which turns into steam, which spins a turbine, which generates electricity.

What sets nuclear apart from many other sources of energy is how dense it is: one pellet of uranium the size of a thimble can produce as much energy as 150 gallons of oil. Because of this, nuclear power plants can produce a lot of energy while taking up relatively little land, making them easier to site.

Today, nuclear energy supplies roughly 20% of all US electricity through 93 operating reactors across 28 states. 

Ninety-three might sound high, but wait until you hear that we used to have 133 nuclear reactors from 1954 to 1978. Why is that expression a thing since you usually tell people the punchline in the same sentence anyways?

Anyway, now that you’ve heard that statistic, you may be wondering what happened since then to shut down, or decommission, so many nuclear reactors.

Three Mile Island. On March 28, 1979, a partial meltdown occurred at a nuclear plant on the Susquehanna River in Pennsylvania. Meltdowns happen when the cooling systems experience failure and cause the uranium fuel to “melt” and possibly eat through its containment structures. When this happens, radioactive materials are released and explosions are possible.

Studies later concluded that the radiation released at Three Mile Island was minimal, but the incident shed light on the scary, worst-case possibilities of nuclear and caused an uproar. Support for building new nuclear plants dropped from 69% in 1977 to 46% in 1979.

Then Came Chernobyl. Seven years later, the Chernobyl plant in the former Soviet Union exploded, causing vast contamination and mass evacuations. 

For decades after, the public and political perception of nuclear was in the pits and the construction of new plants was heavily disincentivized. After Three Mile Island, utilities canceled plans for 39 reactors. Only two new reactors have come online in the US in the 21st century.

With all that whiplash and long history, not many were betting on nuclear two years ago. 

Just four months after taking office, President Trump signed four executive orders to revive the US nuclear industry with the goals of quadrupling our nuclear capacity by 2050, getting 10 new reactors under construction by 2030, and investing billions to stock up on our uranium fuel supplies.

So, why are some parts of the US nutty for nuclear now?

This question has political ties that are above our pay grade, but we can speak to one reason! In some ways, nuclear is part of a bonded pair (*buh dum tis*) to AI and data centers. As we covered in our issue on data centers, AI requires a lot of around-the-clock electricity to run and, as it so happens, nuclear is considered one of the few energy sources that can supply that kind of large, steady, around-the-clock power those data centers require reliably.

While we looped it into our “Renewable Roadshow,” we’re taking it on the chin that we may have contributed to the confusion. Sorry about that one.

Most experts do not classify nuclear energy as "renewable.” Here’s why.

Renewable energy—like solar, wind, and hydropower—comes from sources that replenish themselves at rates faster than humans consume them. However, the uranium used as nuclear fuel is a mined metal and, while it’s currently abundant, it is considered a finite resource.

Still, nuclear is widely classified as a clean energy and a low-carbon energy source because nuclear power plants produce electricity without burning any fuel (recall that it produces electricity from busting atoms apart), which means they release virtually no carbon dioxide or other greenhouse gases during operation.

Some people will go as far to call nuclear “carbon-free,” but this is up for debate since mining the uranium and constructing nuclear plants generate considerable emissions.

The process of nuclear fission also generates waste. Not the type that goes in your septic tank, but the type that’s radioactive and unsafe for any humans to be around, ever. While there are ways to safely store the waste, it’s the amount of it produced that makes things difficult—and therefore unresolved—to store permanently.

In May of 2025, the US DOE announced a series of executive orders to rebuild the nuclear energy industry. While the orders are supportive of the accelerated development of power plants, they also pose some concerns related to safety and stability.

All of this legal mumbo-jumbo can be tough to understand, so let’s make a pros and cons list, shall we?

The Nuclear Energy Institute estimates that US nuclear plants avoid more than 470 million metric tons of CO2 emissions every year- equivalent to taking over 100 million cars off the road. France, which generates over 70% of its electricity from nuclear, has electricity sector emissions that are one-sixth of the European average.

There’s a long road ahead until we live in a world where nuclear energy is widespread, since it takes 6-10 years to build a new plant. However, the possibilities for our energy transition is what draws the climate crowd to nuclear. Since it provides reliable, around-the-clock energy, nuclear is a better contestant than types of renewables to phase out and replace fossil fuels.

The realistic consensus among most energy researchers seems to be that there’s no silver bullet to securing reliable energy that doesn’t contribute to a warming planet. A mix of clean energy sources—including wind, solar, nuclear, and others—is the most viable path to a decarbonized future.

Another month, another interview!!

Next week, we are so eager to share our conversation about agrivoltaics with Ted Gallagher, the Vice President of Solar at MVE Group based in Ephrata, Pennsylvania.

As a former self-described skeptic of agrivoltaics, Ted uses his passions for preserving farm land and expertise on solar energy to explain why he sees agrivoltaics as a way to keep farm land farm land, AND reduce emissions.

Sound counterintuitive? Sounds like you have some reading to look forward to next week!

You and your farmer friends next Tuesday:

Have a specific topic on climate science you want to learn about? Let us know. All responses are anonymous!