In this blog post, we examine the dual nature of nuclear power—both a blessing and a curse—and ponder whether we can safely control it.
The formula ‘E=mc²’ is likely very familiar to many people. Albert Einstein’s achievement, encapsulating the relationship between mass and energy in a few simple letters, is well-known even to the general public. Through this seemingly simple yet profound equation, we gained access to nuclear power—an energy source hundreds of times more efficient than the fossil fuels most commonly used today. Unfortunately, however, the immense energy of nuclear power has also been used to take human lives. Some therefore assess that this great discovery led to the development of nuclear weapons. Nuclear engineering is the field that studies how to safely and peacefully utilize this dual-faced power of the atom.
Nuclear engineering is the field that applies phenomena arising from various reactions within atomic nuclei. Many people wonder how nuclear physics differs from nuclear engineering. While nuclear physics delves into the structure of atomic nuclei, ultimately focusing on how matter is composed, nuclear engineering emphasizes utilizing the energy and particles produced after nuclear reactions in ways beneficial to humanity, rather than just studying that structure. Nuclear engineering can be broadly divided into three main fields: nuclear systems engineering, plasma fusion engineering, and radiation engineering.
First, nuclear systems engineering is the discipline that utilizes the mass defect energy released when uranium reacts with neutrons to undergo nuclear fission. Uranium, with atomic number 92, is the heaviest naturally occurring element. Uranium-235, one of uranium’s isotopes, is the only naturally occurring element on Earth capable of spontaneous nuclear fission. Since each fission event produces 2 to 3 neutrons, under appropriate conditions, a chain reaction can occur, continuously generating energy.
Nuclear systems engineering is called ‘systems engineering’ because properly controlling and maintaining the nuclear fission reaction within a nuclear power plant is crucial. A nuclear power plant consists of three main parts: the reactor core region where the actual nuclear reaction occurs, the thermal-hydraulic system that transfers the heat generated here to the outside and converts it into electricity, and the facilities that control and monitor these systems. Beyond these facilities, evaluation and analysis are also major fields within nuclear systems engineering. As seen in the Fukushima incident of March 2011, inadequate environmental and safety analysis of a nuclear power plant can lead to catastrophic consequences. Therefore, establishing safety regulatory guidelines and conducting thorough accident analysis are also critical tasks of nuclear systems engineering. Furthermore, to operate and maintain such a massive system over a long period, selecting appropriate materials during the initial construction phase is critically important. Since maintaining and analyzing a large power plant solely through human effort is difficult, the process of developing computational models is also part of nuclear systems engineering. Nuclear power plants inevitably produce spent nuclear fuel and low-to-intermediate level waste. The challenge of safely storing this waste for extended periods is a key issue nuclear systems engineering must address in the future. To solve this, active research is underway into methods for reuse through nuclear fuel reprocessing and for the disposal of long-lived radionuclides.
Plasma fusion engineering is the field that studies the complex properties of plasma, the ‘fourth state of matter,’ and the nuclear fusion reactions that sustain the Sun’s light. The electromagnetic properties of plasma, where atomic nuclei separate into ions and electrons at high temperatures, are already widely applied across industries, such as in semiconductor manufacturing and etching processes. Furthermore, research into nuclear fusion using hydrogen, which exists almost infinitely on Earth, is underway to solve future energy problems.
Electrons and ions in the plasma state have the same charge but differ greatly in mass, making it extremely difficult to control the entire system by focusing on just one. Additionally, plasma is inherently extremely hot, and to achieve nuclear fusion on Earth, the plasma must be confined under high pressure. However, materials capable of withstanding these conditions do not yet exist. Therefore, a method was devised to confine the plasma by applying an electromagnetic field to the container, utilizing the electromagnetic properties of electrons and ions. Yet, due to the complex behavior of particles and various difficulties arising from the electromagnetic field, plasma fusion has not yet been realized. Nevertheless, it is anticipated that this can be overcome through the relentless research and experimentation of outstanding engineers.
Finally, radiation engineering is the field that analyzes and applies the various types of radiation emitted during the process where unstable nuclides transform into stable ones. After the Fukushima incident, many people developed fears and concerns about radiation, frequently encountering units like Sv (Sievert) or Gy (Grey) in newspapers. Radiation engineering develops methods to shield against dangerous levels of radiation for humans and instruments to measure it accurately. Furthermore, as medicine advances and human life expectancy increases, the incidence of serious illnesses has also risen. Diagnosing and treating these conditions is another application of radiation engineering. Diagnostic equipment like PET, CT, and even simple X-ray machines all utilize radiation emitted by atomic nuclei. Additionally, while not yet fully realized, cutting-edge cancer treatment research is underway to selectively eliminate only cancer cells using radiation.
Nuclear engineering, interconnected with so many fields, can be considered a convergent, multidisciplinary field. Although nuclear power is dangerous, it is simultaneously a very clean and efficient energy source. I hope more research on nuclear power will be conducted in the future. If people can reduce their fear of nuclear power and show more interest, we can compensate for its weaknesses and use it more safely and peacefully. If that happens, nuclear power will bid farewell to its dark history as a weapon of mass destruction. It will expand the horizons of energy available to humanity and establish itself as a clean energy source contributing to the stable lives of the global population.
