The Nuclear Debate

The Case For and Against Nuclear Energy

As global electricity demand surges due to electrification, economic growth, and population increase, the need for low-carbon energy sources has never been more urgent. Renewable energy sources like solar and wind are expanding rapidly, but their intermittency and land-use challenges raise questions about their ability to meet demand on their own. Nuclear energy is a controversial yet powerful tool that already provides about 9% of global electricity, or about 2,700 TWh.

As of January 2025, there are 417 operational nuclear power reactors worldwide, with a total net installed capacity of approximately 375,320 megawatts electric (MWₑ). 63 reactors are under construction, expected to add about 66,100 MWₑ upon completion.

However, nuclear energy infrastructure is aging. World nuclear energy production in absolute terms has been roughly constant for the last twenty years, but is representing a decreasing percentage of global electricity production and total primary energy consumption as fossil fuel and renewables grow. Most current reactors were built in the mid-20th century, and many are nearing the end of their operational lifespans. Replacing them is costly, they create dangerous waste, and public confidence in nuclear energy has eroded after accidents like Chernobyl and Fukushima.

This leaves us at a critical juncture: Should we stop using nuclear energy? Should we try to extend the life of existing plants while solving renewable energy’s shortcomings? Or should we ramp up investment in advanced nuclear technologies that promise to be safer, cheaper, and more efficient?

The Case for More Nuclear Energy

Low GHG Emissions

Nuclear power generates electricity with negligible greenhouse gas emissions during operation. A 2014 Intergovernmental Panel on Climate Change (IPCC) report confirmed that nuclear has among the lowest lifecycle CO2 emissions of all energy sources, comparable to wind power, accounting for all stages of an energy source's life cycle, including material extraction, construction, operation, and decommissioning.

Small Land Footprint

Nuclear plants pack a remarkable amount of energy into a small footprint—smaller than any other electricity source at only 0.3 square meters per MWh. For countries with limited land or high population densities, nuclear offers a scalable solution. Low land requirements can free up land for agriculture or to preserve natural ecosystems.

24/7 Energy Supply

Nuclear power plants provide a continuous, stable energy supply, operating at over 90% capacity factor, the highest of any energy source. This reliability ensures consistent electricity production regardless of weather or time of day, unlike solar and wind, which depend on sunlight and wind conditions. Continuous energy is crucial for maintaining grid stability, meeting constant base-load electricity demands, and avoiding blackouts. Nuclear’s steady output complements renewables by filling gaps during low production periods, reducing the need for extensive battery storage or backup fossil fuels. France, for instance, derives over 70% of its electricity from nuclear energy, maintaining grid stability while keeping emissions low.

Advanced Reactor Technologies

Emerging designs such as Small Modular Reactors (SMRs) and thorium reactors promise to address many of nuclear power’s current challenges. SMRs, which produce less than 300 megawatts per unit, are designed for scalability, quicker construction, and enhanced safety features, like passive cooling systems. Thorium reactors, on the other hand, use thorium-232 instead of uranium, which is about 4 times as abundant, generating less long-lived radioactive waste and reducing proliferation risks.

Third- and fourth-generation nuclear reactors significantly improve safety, efficiency, and waste management compared to second-generation pressurized water reactors (PWRs). Third-generation designs, like the AP1000, incorporate passive safety systems that rely on gravity and convection, eliminating the need for operator intervention in emergencies. Fourth-generation reactors, such as molten salt and sodium-cooled fast reactors, include inherent safety features like liquid fuel that solidifies to prevent meltdowns. Efficiency also increases, with fuel burnup rates up to 50% higher, reducing uranium consumption and waste. Gen IV reactors can use alternative fuels like thorium or reprocessed waste, while fast reactors transmute long-lived isotopes into shorter-lived ones, mitigating long-term hazards. These advanced reactors generate up to 30% less radioactive waste per megawatt-hour compared to Gen II systems. Additionally, lifespans extend from 40 years in older reactors to 60–80 years in newer designs, improving cost-effectiveness. These innovations make advanced nuclear reactors safer, more sustainable, and better suited for future energy needs.

Less Material and Lifetime Pollution

Compared to renewables, nuclear power requires fewer materials per unit of electricity generated. A nuclear plant’s metal requirements are lower over its lifetime than for solar panels, wind turbines, and their associated batteries. Mining is environmentally disruptive, so less mining means less pollution. The charts below do not include fossil fuels since their mining requirements are 10-50 times higher than renewables.

Safety

Nuclear energy is one of the safest energy sources, with fatalities per unit of energy produced far lower than fossil fuels, on par with solar and wind. Coal and natural gas contribute to millions of deaths annually from air pollution, while nuclear accidents are rare and highly contained. Incidents like Chernobyl and Fukushima, though serious (roughly 400 and 2,300 deaths, respectively), are exceptions in a strong safety record spanning decades. Advanced reactor designs further minimize risks. Public fear of nuclear energy often exaggerates the likelihood and severity of accidents, overshadowing its safety compared to the health and environmental impacts of fossil fuels or even some renewable technologies. Data supports nuclear as a safe option.

Nuclear Fusion

Nuclear fusion promises to create abundant clean energy by replicating the process that powers the sun. By fusing hydrogen isotopes like deuterium and tritium, fusion releases vast amounts of energy with minimal radioactive waste and no greenhouse gas emissions. Fuel sources, including water and lithium, are abundant, and the process avoids the risks of meltdown associated with fission reactors. Recent breakthroughs, such as achieving net energy gain, bring fusion closer to reality, but challenges remain in sustaining reactions and scaling the technology. If realized, fusion could revolutionize global energy, providing reliable, carbon-free power for centuries.

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The Case Against Nuclear Energy

Now that we've discussed all the benefits of nuclear energy, let's explore the challenges and downsides.

Public Fear and Opposition

While not an issue with the technology directly, public fear and opposition can be a barrier to nuclear energy development. People tend to fear things they don't understand, and nuclear energy isn't the easiest thing to understand.

Greenpeace argues that nuclear power is "dangerous, polluting, expensive, and non-renewable," highlighting catastrophic accidents like Chernobyl and Fukushima. Beyond Nuclear International claims "nuclear power is dangerous, uneconomical and unjust."

Right or wrong, anti-nuclear activism shapes public opinion, pressuring governments to scale back or abandon nuclear projects. In countries like Germany, anti-nuclear movements played a key role in driving policies to phase out nuclear energy entirely. Activist-driven campaigns also delay nuclear plant construction through legal challenges, regulatory hurdles, and public opposition to proposed sites. It also affects investor confidence. The perception of nuclear as risky and controversial discourages private investment, exacerbating challenges associated with high upfront costs and long project timelines.

High Costs

Nuclear power plants cost a lot to build. Each plant costs billions because the designs are complex, safety systems are advanced, and regulations are strict. Construction takes a long time—often 10 years or more—which causes delays and drives up costs. Investors don’t like the risks or the long wait for returns, so funding is hard to secure. There’s also no standard design. Each plant is built differently, which adds to the expense. When plants shut down at the end of their usable life, decommissioning them costs billions more. Old reactors must be dismantled, and radioactive waste must be handled carefully. Even though it can provide reliable, clean energy for decades, these high upfront costs are a major barrier to nuclear power.

Dangerous Radioactive Waste

Spent fuel, the most dangerous radioactive waste, waste from nuclear power plants remains dangerous—and much more radioactive than the naturally occurring uranium ore from which it came—for 10,000 years.

Think back 10,000 years in human history to the start of the Neolithic Age. It was over 6,000 years before the invention of writing. As the woolly rhinoceros, cave bear, and saber-toothed cat were dying out, the first human villages and signs of agriculture were appearing. It's that far into the future that we'll need to store nuclear waste safely.

This waste must be kept isolated to protect people and the environment. Right now, most of this waste sits in cooling pools at reactor sites. After it cools, it moves to dry casks—thick steel and concrete containers—for temporary storage. But this is not a permanent solution.

No country has fully solved the problem of long-term disposal. Finland is building a deep geological repository called Onkalo to bury waste safely for 100,000 years. Other nations, like the U.S., have struggled to establish similar sites due to political and public opposition.

For example, the Yucca Mountain waste storage site in Nevada was proposed in the 1980s as the United States' first permanent geological repository for high-level radioactive waste. After decades of research and investment, the project faced strong opposition from Nevada residents, environmental groups, and political leaders, citing concerns over safety, environmental risks, and seismic activity. Today, Yucca Mountain remains unfinished and unused, with no clear plan to revive it. High-level radioactive waste in the U.S. continues to be stored at temporary sites, leaving the country without a permanent disposal solution. Without permanent storage, high-level waste piles up. The risk grows with time.

Globally, nuclear power plants produce approximately 10,000 metric tons of spent nuclear fuel annually, plus at least an order of magnitude more low-level radioactive waste. It equates to around 1 liter of spent fuel per MWh of electricity produced.

The thing about nuclear waste storage is that it seems simple and safe—just put it deep in rocks underground and forget about it—but if something unforeseen does go wrong, it could be very bad. A Black Swan event with nuclear waste storage could pollute groundwater and soils with ionizing radiation for thousands of years. It's unlikely, but so was the 2004 Indian Ocean tsunami, the COVID-19 pandemic, the Great Depression, the Deepwater Horizon oil spill, the sinking of the "unsinkable" Titanic, World War I, and the Black Death that killed over half of the people in Europe.

Weaponization

Nuclear power plants carry risks of weapons proliferation and terrorism in a way that natural gas plants and solar farms do not. Civilian reactors can produce weapons-grade materials like plutonium-239, which could be used for nuclear weapons if diverted. International safeguards, like those from the IAEA, help prevent this, but the risk remains, especially in unstable regions. Terrorists could also target reactors or spent fuel storage, releasing vast amounts of ionizing radiation. Modern plants are built with strong defenses, but no system is perfect. These dangers demand strict oversight, international cooperation, and better technology to lower risks. While these increased safety regulations increase the cost of nuclear energy, the stakes are too high to ignore.

It's Finite

Nuclear energy is not a forever solution. Like coal, oil, and natural gas, the fuel it relies on—uranium—is finite. Current uranium reserves could last around 80 to 100 years at today’s consumption rates. But as the world population grows, industrializes, uses more energy, and switches to electricity, these reserves will not last as long. And if nuclear power expands to meet a larger percentage of global energy demands, those reserves will run out even faster.

Advanced reactor designs, like breeders, can stretch fuel supplies by reusing waste, but they are costly and not widely used. Thorium reactors offer another path, but the technology is still in its infancy. Without breakthroughs, nuclear energy is only a bridge, not a destination. It buys time, but it won't last forever. Even if we assume the absolute best-case scenario, using both uranium and thorium reactors, fuel reprocessing, and a doubling of uranium and thorium reserves, nuclear energy can only last another few hundred years. Presumably, human civilization will last longer than that.

Competition from Renewables

Nuclear energy faces growing competition from renewables. Wind and solar power are getting cheaper every year. Their costs have fallen by more than 70% in the past decade, making them the least expensive sources of new electricity in many parts of the world. They are modular and scalable, meaning projects can be built quickly and expanded as needed. A wind farm or solar array can come online in months, while a nuclear plant can take a decade or more. Similar trends are occurring with the energy storage technologies that complement renewables.

Renewables also have fewer risks. They don’t produce radioactive waste or rely on costly decommissioning. Their decentralized nature makes them less vulnerable to disasters or attacks. They don't require as many highly specialized engineers to install and operate.

Nuclear can provide constant baseload power, which is generally considered an advantage. But once we phase out natural gas peaker plants, it will become more apparent that the power demands of most electric grids are not steady throughout the day. This means energy storage technologies will be required even without renewables if a grid is powered only by nuclear energy.

As renewables scale up, they erode nuclear’s role. Renewable technology is advancing so quickly that it's reducing the need for nuclear energy.

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Conclusion

So nuclear or renewables?

Nuclear energy has strengths, but it also has challenges and risks. It offers steady, low-carbon power that can help reduce the emissions from burning fossil fuels. Renewables are cheaper and faster to build, but they depend on weather and need storage to fill the gaps. Both have a role to play.

Climate change, pollution, and resource depletion are occurring. Every tool that cuts pollution is worth pursuing. Investing in both nuclear and renewables is smart risk management. It gives us options and balances strengths to build a resilient energy system.

Questions for you:

• What is the most compelling case for nuclear energy?

• What is the most persuasive case against it?

• Is it worth it? Why or why not? Let's hear it!