Nuclear power plants require large amounts of water to operate safely, and water is used as a coolant and coolant to ensure the stability and efficiency of the reactor. For this reason, all nuclear power plants are located on water-rich coasts.
On March 11, 2011, the tsunami near Fukushima sent shockwaves around the world. There was a nuclear power plant consisting of six reactors in the area, and the tsunami caused the Fukushima nuclear accident. The disaster highlighted the dangers of nuclear energy and sparked a global debate about nuclear safety. Japan is an earthquake-prone country, and the risk of natural disasters such as tsunamis would have been thoroughly considered when selecting a site for a nuclear power plant. Nevertheless, it can be assumed that there is a particular reason why nuclear power plants are built near the sea. This is closely related to the need for water due to the nature of nuclear power plants.
South Korea, like Japan, is exposed to the risk of natural disasters such as earthquakes. South Korea’s nuclear power plants are also mostly located on the coast and have a similar structure to the Fukushima nuclear plant. This arrangement leads us to question why nuclear power plants must be located next to the sea. Nuclear power is generated by nuclear fission using uranium, and this process uses a huge amount of water. A 1000-megawatt nuclear power plant operating in South Korea requires 60 to 70 tons of water per second. Assuming that there are four nuclear power plants on a single site, that’s a lot of water in just two days.
This large amount of water is essential to keep nuclear power plants running properly. Without water, the reactors cannot be cooled down, which greatly increases the risk of safety accidents. For this reason, all nuclear power plants around the world are located on the coast, relying on a reliable supply of water from the ocean.
Water plays two important roles in nuclear power plants. First, water is used as a decelerant in the primary system. A moderator is a substance used to regulate nuclear reactions by lowering the energy of neutrons that help fission. Second, water is used as a coolant in the secondary system to absorb and release thermal energy from the power plant to turn the turbines, which generate electrical energy. In these two roles, water is an essential element and is indispensable to the operation of nuclear power plants.
Nuclear power plants use water as a decelerant and coolant because it is a stable and reliable material. As a decelerator, water can effectively slow down neutrons, and as a coolant, it can efficiently absorb and dissipate thermal energy. There are other materials that can be used as decelerators and coolants, but water is the best choice for safety and efficiency.
For example, in addition to water, carbon and heavy water can also be used as a decelerant. However, water is more well-studied than carbon or heavy water, so its properties are well understood and can be reacted to accordingly in the event of an accident. On the other hand, carbon burns easily and can pose a risk in the event of a fire, and heavy water has limited use due to nuclear proliferation concerns. This makes water the safest and most reliable choice as a decelerant.
In addition to water, other coolants include liquid metal, carbon dioxide, and helium. However, liquid metals can be explosive when in contact with water, and gaseous coolants are less energy efficient and require higher reactor power, which can lead to the risk of exceeding the melting point of the reactor. For these reasons, water is the best choice as a coolant in terms of safety and efficiency.
Because nuclear power plants have very high power utilization rates, they need a constant supply of materials used as decelerants and coolants in the primary and secondary systems. Since water is the most stable and reliable coolant and decelerant, most nuclear power plants in South Korea use water. The use of water as a decelerant and coolant is an essential choice to ensure the safety of nuclear power plants, which explains why nuclear power plants are often located next to the sea.
By understanding why water is essential and its role in nuclear power plants, we can gain a deeper understanding of the siting and importance of nuclear power plants. Furthermore, we need to continue to research and improve the safety and efficiency of nuclear energy. To prevent tragedies like the Fukushima accident from happening again, we need to be better prepared to operate and manage nuclear power plants. This will ensure that we have safer and more sustainable energy.
