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.

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.

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 ?

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).

Below is an alternative illustration.

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 21^st 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.

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