In this blog post, we will look at why nuclear fusion energy is attracting attention as the ultimate answer to sustainable energy, focusing on scientific principles and future possibilities.
Throughout world history, there have been major events that have greatly changed the international standing of countries through physical confrontation. These events are known as “wars.” The biggest factor determining victory or defeat in war is the weapon system. The history of weapons began in the Stone Age, followed by the Bronze Age and Iron Age, which were eras of short-range weapons. With the introduction of gunpowder in the 10th century, weapons evolved into long-range weapons such as guns and cannons. After about 1,000 years of domination by gunpowder, the most recent change has been the use of nuclear materials in nuclear weapons, which has greatly changed the world. A famous example is the atomic bombs dropped on Hiroshima and Nagasaki in 1945, which ended World War II.
So, does humanity use this “source of power” only for the purpose of killing? No, it does not. Attempts to connect new scientific discoveries about “great power” to peaceful purposes are constantly underway. In other words, we have been striving to develop energy sources to improve the well-being of humanity. With this goal in mind, I would like to explore a new source of power from a peaceful perspective: nuclear fusion power generation technology.
The weapons used for killing and the energy sources used to improve our lives mentioned earlier can be listed as follows. In the era of short-range weapons, weapons were used for warfare as well as for farming, hunting, and construction. Later, with the introduction of gunpowder, guns and cannons were used not only for warfare but also as energy sources for steam engines and thermal power generation, leading to the Industrial Revolution. Next, nuclear technology, introduced about 70 years ago, can be used to manufacture atomic bombs for warfare, but in South Korea, it supplies 30-40% of the country’s energy through nuclear power generation.
Finally, there is nuclear fusion technology, which is the latest attempt at energy innovation and is considered the ultimate energy source. Although nuclear fusion technology has not yet been commercialized as an energy source, it has already been commercialized for use in hydrogen bombs. The examples of power and energy listed above are based on the level of basic science in each era. Let us look at the scientific principles behind these examples before discussing nuclear fusion power generation in earnest.
First, the energy sources of the Stone, Bronze, and Iron Ages were physical collisions. Force is transmitted when a hard object comes into direct contact with another object. On the other hand, gunpowder is a fossil fuel composed mainly of carbon (C) that is burned at high temperatures, causing the surrounding materials to explode and transmit energy. This is caused by carbon reacting chemically with oxygen (O) and converting into other substances, releasing the remaining energy (surplus energy) to the outside. Next, nuclear fuel used in nuclear power generation mainly involves colliding neutrons (n) with uranium (U), causing the uranium to split into two pieces and release the surplus energy to the outside.
Before explaining the basic principles of nuclear fusion, it is necessary to understand the components of matter. All matter is composed of atoms, which consist of a nucleus, which accounts for most of the mass, and light particles called electrons that revolve around it. The reactions between these atoms are called chemical reactions, and when carbon and oxygen react, it is called a combustion reaction. Next, let’s go a little deeper into the unit called an atom and look at particles called nuclei. Nuclei are made up of another type of elementary particle called nucleons, which include protons with a positive charge and neutrons with no charge. The reactions between these nucleons are called nuclear reactions. In particular, the nucleus of a uranium atom consists of 235 or 238 nucleons, and when one of these meets a neutron under certain conditions, the uranium splits into two nuclei, which is called a nuclear fission reaction. Based on this background knowledge, we can see that as time has passed from the past to the present, the size of materials used as energy sources has become smaller and smaller. Based on the development of basic science that can handle smaller and more fundamental particles, this means that the target of energy sources is changing.
Now we can begin to approach the basic principles of nuclear fusion. As the word fusion implies, a nuclear fusion reaction is a reaction in which two nuclei merge to form a single nucleus. Compared to a nuclear fission reaction, the size is basically the same in that it is a reaction between particles called nuclei. However, since nuclei, which are composed of positive and neutral particles, are positive overall, it is more difficult for them to fuse than to fission due to their repulsive nature. This is why, even though the world’s first nuclear fission power plant (reactor) was developed in 1942, nuclear fusion power plants have not yet been completed. Nuclear fusion power technology will remain a major challenge for decades to come. However, as difficult as it is, it has the advantages of being more environmentally friendly than nuclear fission power and having an almost unlimited supply of raw materials on Earth. In other words, unlike nuclear reactors, there is no need to bury spent fuel (radioactive waste) in the ground at the risk of radioactive leakage, and hydrogen (H) and lithium (Li), which are the raw materials for nuclear fusion reactions, can be obtained cheaply and infinitely from the sea and the earth’s crust. Because of these advantages, nuclear fusion technology is considered the ultimate energy source, and it has become my research goal.
In particular, in order for nuclei with repulsive characteristics to fuse, they must collide at very high speeds. Therefore, magnets must be placed and electric currents must be passed through wires to create electric and magnetic fields to accelerate the nuclei. In addition, nuclear fusion reactions are very difficult to achieve due to the demanding conditions required, so the nuclei must be continuously confined within a space (reactor, fusion reactor) where the reaction can occur. The specific topic I am interested in is related to this. I would like to conduct research to analyze the physical conditions under which nuclear fusion reactions can occur while the nuclei are confined within the reactor and subjected to complex electric and magnetic forces.
