top of page
Search

How can “U” find the truth in debates about nuclear energy?

Have you ever seen tons of emotional comments on social media on the topic of nuclear energy or maybe even heard a debate on TV about it? This alternative to fossil fuel is often associated with huge disasters like Chernobyl and Fukushima which have become a popular theme in pop culture. These events significantly worsened the reputation of this energy source. Despite this, it is still one of the most developed alternative energy sources and is responsible for around 9% of all electricity produced worldwide. Its efficiency and reliability attract many agencies responsible for energy production. Because of its numerous advantages and disadvantages it may be hard for you to decide whether you should be happy or worried if the government announces a nuclear plant construction in your country. If so, this article is a perfect place for you to discover the main facts about nuclear energy and come up with your opinion on this topic.


To better understand all of the pros and cons of nuclear energy it is important to understand what physical processes stand behind it. The most important process happening in the nuclear power plants is the nuclear fission. It happens when a nucleus of an unstable isotope splits into two smaller nuclei. Energy E emitted in such process is expressed by a formula:



where

mi is the mass of nuclei before the process,

mf,1 and, mf,2 are the mass of nuclei formed in the process,

c is the speed of light in vacuum


The fact that the formula has the speed of light squared in it shows how big the energy is per unit mass. For the most popular nuclear fuel uranium-235 this value reaches 82 TJ/kg. This U-235 isotope is the most widely used because it is the only suitable isotope which can be easily found naturally. For this type of fuel the process of fission looks the following way:



Fission process of U-235 isotope
Fission process of U-235 isotope


When the U-235 absorbs a neutron it becomes U-236 which is an unstable isotope. Due to this instability, it quickly splits into two smaller nuclei and around two or three neutrons. Each such reaction produces up to 200 MeV (3.2*10-11 J) of energy. However, on average 85% of such energy goes into kinetic energy of the formed nuclei and neutrons. This may seem as a huge energy waste, but those travelling neutrons start other fission processes starting a chain reaction. One reaction starts several others and their number starts to grow exponentially.  Such rapid growth leads to rapid massive energy output and can be useful in nuclear weapons but not in a reactor. To control this growth in the reactor engineers put some neutron observing materials like steel with baron or cadmium. By controlling their position they can achieve a steady reaction speed.


While U-235 can be found naturally in good amounts, it is not the only uranium isotope existing in nature. The most often found isotope is actually U-238 which is found around 150 times more often that U-235. This isotope provides little value to the energy production process as it does not undergo nuclear fission after absorbing a neutron. What is worse, despite not going through the fission process, the isotope still absorbs neutrons produced in the fission process of U-235. Slowing down the emitted neutrons turns out to be a solution to this problem as slowed down neutrons are not captured by U-238 but still are captured by U-235. One of the frequently used ways of slowing down the neutrons is putting water around uranium. The collisions between molecules of water and the products of nuclear fission process speed up the former and slow down the latter. Not only does this decrease the neutron absorption by U-238 but also heats up the water. 

Knowing all of the processes described above allows us to construct a basic model of a nuclear reactor.

Simplified model of a nuclear reactor
Simplified model of a nuclear reactor

The nuclear fuel and control rods are located in a room with thick concrete walls surrounded by water. Due to the processes described above the water is heated up and goes through pipes to another vessel with water kept under higher pressure. Because of this high pressure the water in the vessel has a low boiling temperature and thus turns into steam. This steam later reaches the turbine and rotates it producing electricity. Finally, the steam goes into a condenser which turns it back into water and then the cycle repeats.

Knowing how nuclear power plants work we can analyse the advantages and disadvantages they have.


The first big advantage of the reactor itself is the fact that it does not emit toxic substances in the environment. The water surrounding the nuclear fuel where the fission process takes place is in a cycle which means that no significant amount of radioactive substances go to the environment. Because of this nuclear energy is considered to be a cleaner alternative to fossil fuels, pollution from which is estimated to kill several million people each year and causing extinction of many animal species. Even taking into account accidents on the power plants, nuclear energy causes less environmental damage per unit energy than fossil fuels.

On the other hand the condenser systems often cause heat pollution in the water sources like lakes or rivers they use. Condensers in atomic power plants often use cold water from nearby water sources. When the steam from the turbine condensates, it releases a lot of heat to this water which is later released back to the body of water it was taken from. Due to this the temperature of water in the source increases which is really harmful for local ecosystems as the water becomes too hot for the organisms living there who are not adapted to such temperatures.


On the bright side, nuclear power plants are considered a reliable source of big amounts of energy. As it was mentioned above, just small amounts of fuel generate big amounts of cheap energy. This energy output is quite stable and almost does not depend on external factors like other sources of clean energy like wind and solar which heavily depend on weather conditions. It makes nuclear energy an important part of energy production for countries which develop towards lowering CO2 emissions. Moreover, nuclear reactors have a good energy per used land area ratio. To produce the same amount of energy they require hundreds of times less land than solar and wind energy farms. The land is very important in some countries as it is crucial for agriculture.  


From the other side some extreme external factors like natural disasters or military conflicts can pose a big threat to nuclear reactors. As it was described earlier to maintain a constant rate of reaction and prevent explosion the reaction needs to be carefully controlled. This makes them very sensitive to interventions in their work. Due to this fact the use of them in countries where natural disasters happen is frequently considered to be quite risky. Modern security systems for such emergency situations are being constantly developed but there is still always a chance that they will not manage to save the situation like it happened during the Fukushima accident.

It is also important to remember that nuclear reactors require high-educated workforce to maintain them. On one hand this can be a big limitation as some developing countries can not afford providing education and salaries for such engineers. On the other hand such workplaces can become a stimulus for education development and further economic growth. A similar factor limiting the development of nuclear reactors in developing countries can be high capital costs of their constructions. For many countries it can be hard to afford it. 


It is worth mentioning that the nuclear fuel is radioactive not only while it stays inside the reactor but also before and after that. When the fuel has few radioactive isotopes in it to maintain the chain reaction it still stays radioactive and often becomes radioactive waste. While there are modern technologies which allow us to safely secure the waste, it still requires some space. This waste must stay in safe storages for thousands of years which means that the decisions about it require very carefully planning and are a big responsibility as they will affect hundreds of future generations.


The process of mining the fuel, similarly to the waste management, has its own nuances. The most used method of uranium mining nowadays is in-situ leaching. An acid, often sulfuric, is used to start a reaction with uranium and get it from the ground. Putting such acid under the ground can seriously pollute ground water posing a threat to nearby ecosystems. Another method, used for less deeper sources, open-pit mining produces nuclear dust which can cause respiratory diseases among surrounding inhabitants. Moreover, all of the methods produce a lot of byproducts which also require careful management which is not always properly done.


Krapf, Hansueli. “Leibstadt Nuclear Power Plant Aerial View.” Wikimedia Commons, 10 May 2011, commons.wikimedia.org/wiki/File:2011-05-10_18-57-46_Switzerland_-_Wil_crop.jpg. Accessed 14 Mar. 2026. Licensed Creative Commons Attribution-Share Alike 3.0 Unported .
Krapf, Hansueli. “Leibstadt Nuclear Power Plant Aerial View.” Wikimedia Commons, 10 May 2011, commons.wikimedia.org/wiki/File:2011-05-10_18-57-46_Switzerland_-_Wil_crop.jpg. Accessed 14 Mar. 2026. Licensed Creative Commons Attribution-Share Alike 3.0 Unported .

A big question about nuclear fuel is how much of it do we have. There are some estimations that the sources we know now are enough for only about a century of usage. However, scientists are constantly coming up with technologies on how the nuclear waste, similarly to the usual waste, can be recycled. Sometimes we can artificially produce isotopes applicable for chain reaction from. For example uranium-238, present in large amounts even in the used fuel can be transformed to plutonium-239 which is a good isotope for a chain reaction just like uranium-235. These technologies can significantly increase the time during which we will be able to use nuclear energy and reduce the amount of nuclear waste. 


Reading the analysis above you have probably understood why nuclear energy is so often emotionally discussed. Both its potential benefits and threats are much bigger than in the case of other types of energy.  Are the benefits we can get from nuclear energy worth the potential risks it brings? Should we develop it or focus on other types of energy? It is definitely a question that will continue to be actively discussed for years.


Page design: Asya Chub

Bibliography

Photo:






.


Comments

bottom of page