Why Nuclear Energy is Safe and How it Works

Varsha Prasad
5 min readMar 17, 2022


Nuclear power is an eco-friendly power source that produces no greenhouse gas emissions during operation. Unlike fossil fuel-fired power plants, nuclear reactors do not produce air pollution or carbon dioxide while operating.

Nuclear Safety

Our society has a bad perception when it comes to nuclear power because of atomic bombs like Hiroshima and Nagasaki as well as nuclear plant accidents like Fukushima and Chernobyl. Although these things have disasters, both of the plants admitted to the fact that they could have avoided the accident with proper training and regulation.

The Nuclear Navy has logged over 5,400 reactor years of accident-free operations and travelled over 130 million miles on nuclear energy, enough to circle the earth 3,500 times. These plants have operators who are in their 20s and 30s with no accidents but the difference is they had the discipline to follow the rules.

Many of the old nuclear plants that have accidents also have very old system designs from the 1960s. New designs made in the past 20 years have many safety mechanisms. For example, if a part overheats, it automatically shuts down making accidents almost impossible.

The graph above shows the safety of energy sources in deaths per terawatt hour. One terawatt hour is equivalent to one trillion watts. Nuclear energy has 99.8% fewer deaths than brown coal, 99.7% fewer than coal, 99.6% fewer than oil and 97.5% fewer than gas. Nuclear plants are not something to be afraid of because if handled properly, they are an eco-friendly way of getting a lot of energy.

How Nuclear Fission Works

Nuclear fission is a reaction that happens on an atomic level that produces energy. In the figure above, the example of uranium-235 is being used, which is the isotope of uranium that is usually used. A neutron gets absorbed into the nucleus, which makes it unstable, so it decays into two fragments. The two fragments are called daughter nuclei.

The things released are the different elements fragments, other neutrons and energy. The neutrons hit more nuclei and make those unstable nuclei as well. The cycle of neutrons decaying into more nuclei into more neutrons is called the chain reaction.

This is a diagram of the natural decay chain of Uranium-235(without any neutrons absorbed), which shows us.

Beta-decay is a type of radioactive day which occurs when a nucleus has too many protons or neutrons. This reaction goes through beta minus decay where the weak interaction changes an atomic nucleus into a nucleus with an atomic number increased by one. It also emits an electron and an electron antineutrino (a special type of electron).

In this experiment, we are studying Uranium-235 and when a neutron gets absorbed, it becomes the unstable isotope, Uranium-236. The uranium-236 atom rapidly decays into an atom of Ba-141 (barium), an atom of Kr-92 (krypton) and around three neutrons.

There are two types of neutrons that can get absorbed into the nuclei, a thermal neutron and a fast neutron. A thermal neutron, the type of neutron being analyzed in this paper, is a slow-moving neutron with less than 0.1 electron volts(eV). A fast neutron is a neutron released as a product of fission and has a high kinetic energy of 10,000,000 eV.

Fission Reactors

The different parts of the nuclear reactor are:

Nuclear fuel(the uranium/plutonium): It’s the uranium/plutonium isotope that splits when triggered by an incoming neutron. The fuel helps in rods so that the neutrons release fly out and cause nuclear fission in other rods.

Moderator: a graphite core slows down the neutrons so they’re more likely to be absorbed into a nearby fuel rod.

Control rods: These are used to absorb excess neutrons and control the rate of reactions. They’re raised and lowered to stop neutrons from travelling between fuel rods. They can slow down and change the speed of the chain reaction.

Coolant: It’s a liquid used to transfer thermal energy in a system. It is heated up by the energy released from the fission reactions and is used to boil water to drive turbines in the power station.

Concrete shield: Products of reaction are radioactive and are a hazard and the shield protects humans from it.

The pros of nuclear are they don’t have polluting gases, a low cost after initial costs, low fuel amount reduces mining and transportation effect on the environment and a power station has a long lifetime. Some of the cons of nuclear are that the waste is radioactive and can be expensive to dispose of, local thermal pollution from wastewater affects marine life, high initial costs and the public perception is very negative. Most of the cons include the disposal of nuclear waste but it can be stored and used as energy in the future and uranium mining.

Countries are thinking about if they want to implement nuclear or not but many energy specialists say it’s one of the most eco-friendly energy sources. Places like France use nuclear power for 75% of all of their power whereas places like Canada and the US are 15–20%. In order to move towards a carbon-neutral future, nuclear will be one of the leading energy sources.