[News Terms] Dream Energy, What Is 'Nuclear Fusion' That Took Its First Step with the Artificial Sun?

Technology to Obtain Energy by Element Fusion
Less Waste and Safer than Nuclear Power Plants

[Asia Economy Reporter Lim Ju-hyung] A research institute under the U.S. Department of Energy is gaining attention for achieving a significant milestone in nuclear fusion power. Nuclear fusion power is a technology that generates electricity by producing ultra-high-temperature plasma, implemented in a way similar to the principle by which the sun emits light and heat, and is sometimes called the "artificial sun." Unlike nuclear power generation, it produces significantly less waste and poses much lower accident risks, making it regarded as the "dream clean energy." The global scientific community has devoted nearly 90 years to realizing nuclear fusion, but still faces various challenges.

Jennifer Granholm, U.S. Secretary of Energy, announced on the 13th (local time) that the research team at the National Ignition Facility (NIF), a nuclear fusion reactor research institution under the government-affiliated Lawrence Livermore National Laboratory, has succeeded in "nuclear fusion ignition." Nuclear fusion ignition means that the energy produced by the reactor exceeds the energy consumed to initiate the fusion reaction. Secretary Granholm emphasized that although there is still a long way to go before commercial use of fusion reactors, achieving net energy gain in an experimental fusion reactor is a "breakthrough achievement."

Dream Clean Energy... The Key is Creating the 'Artificial Sun'

The nuclear fusion praised by Secretary Granholm refers to the physical phenomenon where light elements, including hydrogen, combine. When light elements fuse to form heavier particles, an enormous amount of energy is released in the process, and the "fusion reactor" aims to use this as a power source.

It differs from "nuclear fission," which is currently used in nuclear power plants. Nuclear fission uses the energy released when atomic nuclei split, whereas nuclear fusion produces much more energy per unit mass than fission and generates far less radioactive waste. This characteristic is why nuclear fusion power is considered the dream clean energy.

The sun is a star that creates an ultra-high temperature and ultra-high pressure environment through gravity to generate plasma, and continuously undergoes nuclear fusion reactions inside. / Photo by Yonhap News

Nuclear fusion is also found in nature. The sun is a prime example. The sun is a star composed of hydrogen, helium, and other elements, and due to its strong internal gravity, these materials form a "plasma" state. Because this plasma continuously undergoes fusion reactions, the sun has been emitting tremendous light and heat for billions of years. Today, fusion reactors created in laboratories worldwide mimic this plasma to obtain thermal energy.

Inertial Confinement vs Magnetic Confinement... Nearly 90 Years of R&D

Since British physicist Ernest Rutherford succeeded in the world's first nuclear fusion experiment in 1934, countries have developed fusion reactors using different methods. Today, fusion methods are broadly divided into two types: inertial confinement and magnetic confinement.

Inertial confinement involves placing particles that serve as "fuel" for fusion reactions, such as deuterium and tritium, inside a capsule, then firing powerful lasers at it to create an ultra-high-pressure and ultra-high-temperature state that forms plasma. The recent U.S. laboratory experiment is a representative case of inertial confinement, where a 2.05-megajoule (MJ) laser was fired to produce 3.15 MJ of fusion energy.

On the other hand, magnetic confinement uses a device called a "tokamak." It is mainly a donut-shaped cylinder that generates a magnetic field inside using superconductors and coils to confine plasma for extended periods. The European joint project ITER, the UK's JET and MAST, and Korea's K-STAR all use tokamaks for magnetic confinement fusion reactors.

Korea's K-STAR is a magnetic confinement fusion reactor using a donut-shaped tokamak device. / Photo by Yonhap News

Both inertial confinement and magnetic confinement have limitations. First, inertial confinement requires continuously firing 192 powerful lasers at a single point to maintain plasma. However, focusing about 190 high-energy lasers uniformly on one spot and achieving high energy efficiency in such an environment is nearly impossible with current laser technology. For this reason, the NIF research team admitted in interviews with U.S. media that "there are not only scientific but also technical obstacles."

Meanwhile, magnetic confinement can relatively easily hold plasma, but the problem is that if the plasma inside the tokamak becomes even slightly unstable or fluctuates, it immediately collapses. Korea's K-STAR, a small tokamak device only one twenty-fifth the size of ITER, managed to maintain plasma for about 30 seconds during its trial run last year.

This content was produced with the assistance of AI translation services.