Nuclear energy has a dual nature: it provides energy that is hundreds of times more efficient, but it is also dangerous. Nuclear engineering studies how to harness it safely and peacefully, and whether it becomes a blessing or a disaster for humanity depends on our choices and efforts.
The formula “E=mc²” will be very familiar to many people, and Albert Einstein’s achievement of summarizing the relationship between mass and energy in a simple formula of just a few letters is well known to the general public. This seemingly simple but profound relationship gave us nuclear power, a source of energy that is hundreds of times more efficient than the most common fossil fuels used today. Unfortunately, the enormous energy of nuclear power has also been used to kill people, and some credit this great discovery with leading to the development of nuclear weapons. Nuclear engineering is the study of how to safely and peacefully utilize this two-faced Janus.
Nuclear engineering is the application of the phenomena that occur in the various reactions of atomic nuclei. Many people wonder how nuclear physics differs from nuclear engineering. While nuclear physics delves into the structure of the atomic nucleus and ultimately focuses on how matter is organized, nuclear engineering focuses less on that structure and more on harnessing the energy and particles that result from nuclear reactions in ways that are useful to humans. Nuclear engineering can be divided into three broad areas: Nuclear Systems Engineering, Plasma Fusion Engineering, and Radiation Engineering.
First, nuclear systems engineering harnesses the mass deficit energy that occurs when uranium reacts with neutrons and fission. With an atomic number of 92, uranium is the heaviest element in nature. One of its isotopes, uranium-235, is the only element on Earth that can spontaneously fission in its natural state. Each fission produces two to three neutrons, which means that if the right conditions are met, a chain reaction can occur and continue to generate energy.
Nuclear systems engineering is called “systems engineering” because of the importance of properly controlling and maintaining the fission reaction in a nuclear power plant. A nuclear power plant consists of three parts: the reactor core area where the actual nuclear reaction takes place, the thermo-hydraulic system that transfers the heat generated to the outside and converts it into electricity, and the facilities that control and inspect it. These facilities, as well as their evaluation and analysis, are the main areas of nuclear systems engineering. As the Fukushima disaster in March 2011 demonstrated, improper environmental and safety analysis of nuclear power plants can be catastrophic, which is why preparing safety regulatory guidelines and conducting thorough analyses of accidents are also important tasks of nuclear systems engineering. In addition, proper selection of materials during the initial construction phase is crucial for the long-term operation and maintenance of such a huge system. Computational modeling is also part of nuclear systems engineering, as it is difficult to maintain and analyze such a huge power plant by human power alone. Nuclear power plants inevitably generate spent nuclear fuel and low- and intermediate-level waste, and the safe storage of these for long periods of time is a challenge that nuclear systems engineering will need to address in the future. To address this, active research is being conducted on nuclear fuel reprocessing for reuse and long-lived nuclide decay.
Plasma nuclear fusion engineering is the study of the complex properties of plasma, the “fourth state of matter,” and the nuclear fusion reaction, which is the principle by which the sun continuously shines. The electromagnetic properties of plasma, in which atomic nuclei are separated into ions and electrons at high temperatures, have already found many applications in industry, such as in semiconductor manufacturing and etching processes. Nuclear fusion using hydrogen, which exists almost inexhaustibly on Earth, is also being researched to solve future energy problems.
Electrons and ions in a plasma state have the same charge but a large difference in mass, making it difficult to control the entire system by focusing on just one side. In addition, plasmas are inherently very hot, and in order to realize nuclear fusion on Earth, plasmas must be confined under high pressure, but no material exists that can withstand this. Therefore, the electromagnetic properties of electrons and ions have been exploited to trap them in a container with an electromagnetic field. However, due to the complex behavior of the particles and the many difficulties derived from the electromagnetic field, plasma nuclear fusion has not yet been realized. However, it is hoped that through constant research and experimentation by highly qualified engineers, these difficulties can be overcome.
Finally, radiation engineering is the analysis and application of various radiations that occur during the transmutation of unstable nuclides into stable ones. After the Fukushima disaster, many people have become fearful and concerned about radiation, and units such as Sv (Sievert) and Gy (Gray) have become commonplace in newspapers. Radiation engineering develops methods of shielding dangerous amounts of radiation from humans and instruments to accurately measure it. Also, as medical advances have increased the average life expectancy of humans, more people are becoming seriously ill. Diagnosing and treating them is one of the applications of radiation engineering. Diagnostic devices such as PET, CT, and even simple x-rays all utilize radiation emitted by atomic nuclei. There is also advanced cancer treatment research that uses radiation to selectively kill cancer cells, although this is not yet fully realized.
With so many connections, nuclear engineering is an interdisciplinary, multidisciplinary field. Although nuclear energy is dangerous, it is also a very clean and efficient source of energy, and I hope that more research will be done in the future. If people are less afraid of nuclear energy and more interested in it, we will be able to improve its weaknesses and make it safer and more peaceful to use. If that happens, nuclear energy will say goodbye to its dark history as a weapon of mass destruction and become a clean source of energy that contributes to the stable lives of the world’s population by expanding the horizons of human energy.
