Nuclear Energy is Relatively Clean and Safe

Superfact 96: Nuclear power is a relatively clean and safe energy source that produces no atmospheric emissions during operation. However, there are some problems with nuclear power, but they are often overblown.

The photo shows the three mile island nuclear plant from the across the shore of Susquehanna River in Londonderry Township.
The Three Mile Island Nuclear Power Plant south of Harrisburg, Pennsylvania. March 28, 1979, a nuclear accident at the Three Mile Island nuclear power plant sent shockwaves across the world, raising fears about nuclear power. However, no one died, and no one was hurt. Shutterstock Asset id: 2512612545 by Aubrie K

Clean energy sources are often defamed by disinformation and misunderstandings. For example, wind power turbines are not bird killing machines. Contrary to what you often hear wind power is indeed a very clean, cheap and sustainable energy source. Nuclear power is another misunderstood energy source. Wind power, solar power, hydro, and nuclear power are all considered clean energy because they produce no greenhouse gases or air pollution during operation and they also have very low life-cycle emissions.

The graph below from Our World in Data depicting lifetime greenhouse gas emissions (construction, operation, disposal) and safety data for the European Union, show that the lifetime greenhouse gas emissions of coal power is 162 times higher than those of nuclear power and coal kill 820 times as many people as nuclear power. The lifetime greenhouse gas emissions of natural gas are 120 times higher than those of nuclear power and kill 613 times as many people as nuclear power. The difference is staggering.

The graph depicts death rates and greenhouse gas emissions per unit for different energy sources including coal, oil, natural gas, biomass, hydropower, wind, nuclear power, and solar. | Nuclear Energy is Relatively Clean and Safe
Death rates from fossil fuels and biomass are based on state-of-the art plants with pollution control in Europe and are based on older models of the impacts of air pollution on health. This means that these death rates are likely to be very conservative. For further discussion see our article: OurWorldinData.org/safest-sources-of-energy. Electricity shares are given for 2021. Data sources: Markandya & Wilkinson (2007); UNSCEAR (2008: 2018); Sovacol et al. (2016); IPCC AR5 (2014); UNECE (2022); Ember Energy (2001). OurWorldinData.org – Research and data to make progress against the world’s largest problems. Licensed under CC-BY by the authors Hannah Ritchie and Max Roser. Citation : Hannah Ritchie (2020) – “What are the safest and cleanest sources of energy?” Published online at OurWorldinData.org. Retrieved from: ‘https://archive.ourworldindata.org/20260202-100556/safest-sources-of-energy.html’ [Online Resource] (archived on February 2, 2026).

In the graph above, greenhouse gas emissions are measured of CO2 equivalents per Gigawatt-hour of electricity over the lifecycle of the power plant. 1 Gigawatt-hour is the annual electricity consumption of 150 people in the EU. Death rate from accidents and air pollution is measured as deaths per Terawatt hour of electricity production. 1 terawatt hour is the annual electricity consumption of 150,000 people in the EU.

I should mention that there are problems with nuclear power that are not entirely covered by the graph above, including radioactive waste, a history of spectacular accidents, and a perceived connection to nuclear arms. However, as you will see later in this post, even though these problems get a lot of media attention, they are not as scary as one might think. However, it should be noted that nuclear power in its current form is not a cheap source of energy, but that is a different topic.

I consider this a super fact because nuclear power is often thought of as an extremely dangerous and dirty source of energy, which is not the case.

How Does Nuclear Power Work ?

From left to right : a neutron strikes a uranium nucleus, and it breaks apart into a Krypton and Barium isotope and release three neutrons, which strike three uranium nucleuses, causing three fission events and releasing nine neutrons in total, etc.
Illustration of nuclear chain reaction. Uranium-235 fission. Shutterstock asset id: 73714504 by Mpanchenko. Note I corrected an error in the picture.

The fuel (fuel rods) in a nuclear power station consists primarily of stacked ceramic pellets made of low enriched uranium dioxide housed inside sealed metal tubes. The uranium consists primarily of two uranium isotopes U-238, which has 92 protons and 146 neutrons and U-235, which has 92 protons and 143 neutrons. Uranium always has 92 protons. The isotope that is used for fission is U-235. Natural Uranium consists of 0.7% U-235, trace amounts of U-236 and the rest (99.3%) is U-238. The uranium in nuclear fuel rods is either natural (0.7% U-235) or a few percent of U-235 (low enriched uranium). This should be contrasted with a uranium atomic bomb which has at least 80% U-235 (highly enriched).

A nuclear power plant generates electricity using heat from nuclear reactions. Inside the reactor, atoms of fuel (uranium) undergo nuclear fission, where they split apart and release a large amount of heat. The fuel rods (see picture below) in a nuclear power station consist primarily of stacked ceramic pellets made of low enriched uranium dioxide housed inside sealed metal tubes. There are also control rods in a nuclear power station, which consist of materials with a high neutron absorption cross-section. The control rods are used to regulate the reaction. If they are fully inserted the reaction will stop. Also note that nuclear reactors have a containment shield (at least in western countries).

How a nuclear reactor generates electricity using fuel rods, control rods, steam, turbines, and generators diagram hand drawn schematic vector.
Fission generates heat, which generates high pressure steam, which pushes a turbine around, which turns a generator, which generates electricity, which is transformed to the right voltage and delivered to customers. Science educational illustration Shutterstock Asset id: 2658971563 by Alexander_P

Below is an alternative illustration.

Fission generates heat, which generates high pressure steam, which pushes a turbine around, which turns a generator, which generates electricity, which is transformed to the right voltage and delivered to customers. The picture also shows a cooling tower and illustrates how a nuclear plant uses water.
A nuclear power plant generates electricity by using heat from nuclear fission to produce steam, which drives turbines connected to electrical generators. This illustration also depicts the nuclear power plant’s use of water for cooling. Don’t worry, the water will not turn radioactive. It is a separate isolated loop. Shutterstock Asset id: 2525528665 by Papia Majumder.
The photo is taken in 2024 and shows the Three Mile Island Nuclear Plant with a nuclear reactor building and the associated coolant tower. | Nuclear Energy is Relatively Clean and Safe
Three Mile Island Nuclear Plant, located in Pennsylvania, is known for a partial meltdown in 1979 Shutterstock. This photo shows the reactor as well as the cooling tower. Asset id: 2520903273 by Amy Lutz.

What about Chernobyl ?

The Chernobyl disaster, which occurred on April 26, 1986, was the worst nuclear disaster in history. 50 people died as a direct result of the disaster and an estimated 4,000, perhaps 10,000 future cancer deaths are predicted from the disaster. However, it should be noted that an estimated half million people died from coal pollution in the United States over the first two decades of the 21st century. You have to compare.

Another, thing to keep in mind is that the Chernobyl reactors were RBMK reactors (Reaktor Bolshoy Moshchnosti Kanalnyy), an extremely flawed, old and dangerous design that only exists in Russia (or the former Soviet Union). Above I mentioned that the control rods slow down the nuclear reaction when inserted between the fuel rods and stop the reaction when fully inserted. In an RBMK reactor, it is the other way around. The control rods speed up the reaction when inserted. Add the fact that the Chernobyl reactor did not have a containment shield designed to contain a major release of radioactivity, unlike Western reactors and that the Soviet Union was an authoritarian and secretive regime that made things much worse. A nuclear disaster similar to Chernobyl is highly unlikely to happen in the West.

The Fukushima nuclear disaster was caused by a severe earthquake and a 15 meter tsunami. Around 2,300 died from the evacuation, and 15,000 people died from the Earthquake, but it is estimated that no one, or perhaps one person died as a direct result from the nuclear disaster itself. As mentioned no one died from the Three Mile Island accident.

What about Radioactive Waste?

Radioactive waste stored on-site at nuclear power stations (spent fuel) is often millions of times more radioactive than long-term disposal waste. It is important to remember that highly radioactive isotopes decay fast (that’s why they are dangerous), which means that long-term disposal waste is not very dangerous. We are surrounded by radioactivity and our by far largest exposure to ionizing radiation comes from the radon in our basements.

Does nuclear power for energy generation increase the risk for nuclear weapons proliferation?

While commercial nuclear energy and weapons programs share technology, they are distinct processes. The historical data and studies show that national nuclear energy programs in general don’t lead to the development of nuclear weapons. No country officially developed nuclear weapons based on a pre-existing commercial nuclear power industry. Typically, nuclear-armed nations developed dedicated, military-focused, and often secret reactors to produce plutonium or facilities to enrich uranium for weapons.  Also, the issue is mostly moot for countries that already have nuclear weapons, such as the United States.

Conclusion

Nuclear power is clean and safe. It might be our cleanest energy source that can provide baseload power. However, there are other concerns including the possibility of spectacular accidents, radioactive waste and the possibility that nuclear power for energy might aid nuclear weapons proliferation. Luckily, it appears that these concerns are overblown. It should be noted that nuclear power, as implemented today, is not cheap energy, but that is a different topic.




To see the Other Super Facts click here

Unknown's avatar

Author: thomasstigwikman

My name is Thomas Wikman. I am a software/robotics engineer with a background in physics. I am currently retired. I took early retirement. I am a dog lover, and especially a Leonberger lover, a home brewer, craft beer enthusiast, I’m learning French, and I am an avid reader. I live in Dallas, Texas, but I am originally from Sweden. I am married to Claudia, and we have three children. I have two blogs. The first feature the crazy adventures of our Leonberger Le Bronco von der Löwenhöhle as well as information on Leonbergers. The second blog, superfactful, feature information and facts I think are very interesting. With this blog I would like to create a list of facts that are accepted as true among the experts of the field and yet disputed amongst the public or highly surprising. These facts are special and in lieu of a better word I call them super-facts.

40 thoughts on “Nuclear Energy is Relatively Clean and Safe”

      1. Hi Thomas, he’s not quite sure yet (he’s only 15!). His other option was technology-led defense, possibly engineering aircraft. I showed him your article, and we were amazed by your nuclear chain-reaction diagram! Thanks for this interesting post.

        Liked by 1 person

        1. Thank you so much for your kind words Ada. I used to work for the division of Ericsson (in Sweden) that built the JAS Gripen military fighter jet. I helped design and build the presentation system for the Pilot. Yes your son is still very young but he sounds ambitious. I wish him all the best with deciding which field to enter.

          Liked by 1 person

          1. Oh, wow, Thomas, that’s so cool! I’ll definitely tell him! He’ll be curious and super impressed that you worked for the division of Ericsson that built a military fighter jet – it’s actually really similar to what he wants to do (which I think is to do with drones/helicopters?). It’s one of his options, I think. You’re such an inspiration for young people wanting to enter the industry!

            Like

    1. Thank you so much Sara. I think most people feel like you, including my wife and perhaps me too. However, I’ve visited the nuclear power station Three Mile Island, Middletown, a couple of times and I’ve talked to people and the people in Middletown were perfectly comfortable with it. On the other hand they may not be the majority.

      Liked by 1 person

        1. Always better to be safe than sorry. However, I am not particurly afraid of American, Canadian or Swedish nuclear power stations. Russian RBMK reactors, well that is a different story.

          Like

  1. Wow, this is the most thorough and easy to understand articles I’ve ever read on nuclear energy. The graphs helped but seem incomplete without the additional information you included about Chernoble. Probably more people have seen the movie about that tragedy and all their knowledge and emotions about nuclear energy stem from that information. The only problem with your fabulous article is exposure.

    Liked by 1 person

        1. Yes you are right Marsha. Fossil fuels played a very important role in the industrial revolution and before oil/coal etc., we were nearly hunting whales, seals, etc., to extinction to get oil. However, fossil fuels also caused an enormous damage to the environment, human life, and as we would later realize climate. Now we have alternatives that are much cleaner and safer, wind, solar, batteries, nuclear, and geothermal, which is small but growing. Perhaps we will have even better energy sources in the future, such as fusion power. We humans are inventing better technology.

          Liked by 1 person

            1. Maybe, but I think that overall we are making progress. Ozone depleting gases used to be a huge and very dangerous problem. However, emissions of ozone-depleting gases have fallen by 99 Percent, in fact 99.7%. The problem has almost entirely vanished. We used to be very worried about acid rain but sulfur dioxide pollution has fallen by 95 percent in the US. Some problems, like global warming are getting worse, because they are tough problems to solve and developing countries want to be prosperous, like Europe and the US. However, we have solutions, even though we haven’t fully implemented them. But we are working on it, or somewhat working on it.

              Liked by 1 person

                1. Thank you Marsha. The so called ozone hole is not gone but it is shrinking thanks to the ozone depleting gases being pretty much gone. This is largely due to the Montreal protocol in 1987, where nations agreed to phase them out. There is both bad and good news in this world. However, good news tend to be more boring so you hear of it less.

                  Liked by 1 person

                  1. This is true, but some news stations try to focus on a few news stories that are positive. Not enough, though. One of the reasons that blogging is so important is just that. News is made of sound bites. Nothing ever goes very deep, and the same sound bites are repeated over and over again. Repetition is a great learning tool for memorizing facts, but it’s doesn’t promote much in the way of thinking skills or breadth of knowledge.

                    Like

  2. As an Alaskan, I cannot understand why my state does not make preparation to accommodate a cleaner future and invest in nuclear energy. Finland is a comparable climate, and they are working wonders with nuclear. If we ever get out of this fossil fuel rut, I would think it would be the best investment the US could make in Alaska.

    Liked by 1 person

  3. Hi Thomas, this is an interesting article. In terms of risk margin, the numbers of deaths are very low. Of course, any deaths is a terrible thing but I understand that from a commercial perspective it is a very acceptable percentage. It’s a bit like the vaccination risk, sufficiently small to be acceptable from a scientific point of view.

    Liked by 1 person

    1. There is always the risk that governments try to cover up things. This is certainly the case in authoritarian regimes. In democracies with a free press this is a little bit harder. Thank you so much Patti.

      Like

  4. I think our use of fossil fuels will be reduced or eliminated by combinations of different clean energy sources. Nuclear may be one of them, despite its expense. Canada is said to be producing (or planning to; I’m not sure) a type of small modular nuclear reactor.

    Liked by 1 person

    1. Small modular reactors is certainly an interesting prospect. We have a Senator here in Texas (Ted Cruz) who is very much into Small Modular Reactors. You are right the cheapest and most efficient way of moving on from fossil fuels is a combination of clean energy, wind, solar, hydro, batteries, other storage, geothermal, natural gas with carbon capture, and nuclear. Thank you for your interesting comment Audrey.

      Liked by 1 person

  5. Thanks for the informative post about how nuclear reactors work and your clear-headed perspective on their relative safety. Accidents and natural disasters have a way of sticking in our memory, so it’s good to step back and put them in perspective.

    Liked by 1 person

    1. Thank you so much for your kind words David. Yes something are more spectacular but the creeping every day disaster from pollution may not get as much attention. Data and correctly interpreted statistics can help put things in perspective.

      Liked by 1 person

  6. There is an interesting and relevant article in a recent article in The Spectator.
    See https://spectator.com/article/the-true-cost-of-chernobyl-isnt-what-you-think/#comments-container
    It makes the point that moving away from nuclear power was massively accelerated by the Chernobyl disaster and this has had a big impact.

    Here is the final sentence: “But, in the end, Chernobyl’s true impact was the lives cut short by avoidable air pollution. Fear of nuclear power killed more people than nuclear power ever has”.

    Like

Leave a comment