Scientists in South Korea have made a major breakthrough in nuclear fusion research. The Korea Superconducting Tokamak Advanced Research (KSTAR) reactor has set a new record by super heating a plasma loop to 180 million degrees Fahrenheit (100 million degrees Celsius) for 48 seconds. This beats the previous record of 31 seconds, also set by KSTAR in 2021. The achievement is another step towards developing nuclear fusion as a near-limitless and clean energy source.

Nuclear fusion is the process that powers stars, including our Sun. It occurs when hydrogen atoms fuse together to form helium under extreme pressure and temperature. This reaction releases vast amounts of energy without producing harmful greenhouse gases or long-lasting radioactive waste, making it a highly attractive option for sustainable energy. For over 70 years, scientists have been trying to replicate this process on Earth.

However, achieving fusion in a controlled environment is extremely difficult. While stars benefit from immense pressure to sustain fusion at around 27 million degrees Fahrenheit (15 million degrees Celsius), fusion reactors on Earth need to reach much higher temperatures—often exceeding 180 million degrees Fahrenheit (100 million degrees Celsius)—because they operate at much lower pressures. The challenge lies in finding a way to keep this super heated plasma contained long enough for fusion to occur.

The most common design for fusion reactors is the tokamak, a donut-shaped chamber that uses magnetic fields to trap and contain super heated plasma. This plasma, a state of matter made of positive ions and free electrons, must be kept stable and in place long enough for the hydrogen atoms to fuse and release energy.

Soviet scientist Natan Yavlinsky designed the first tokamak reactor in 1958, and since then, researchers have been working to improve the design. Despite significant progress, no tokamak has been able to produce more energy than it consumes, which remains the ultimate goal of fusion energy research.

The KSTAR reactor’s recent breakthrough marks another important step forward. By tweaking the reactor’s design—such as replacing carbon components with tungsten to improve the efficiency of its divertors, which extract heat and ash—the scientists were able to significantly extend the plasma’s burning time from 31 seconds to 48 seconds.

Si-Woo Yoon, the director of the KSTAR Research Center, noted that this success came despite the challenges of working with the new tungsten divertors. The team now has its sights set on an even bigger goal: by 2026, they hope to sustain the plasma at 180 million degrees Fahrenheit for a full 300 seconds.

This achievement underscores the continued progress in fusion research, but it also highlights the long road ahead. While KSTAR’s accomplishment brings us closer to creating a sustainable source of clean energy, there is still much to learn before fusion can become a practical solution to the world’s energy needs.

Recent achievements in fusion energy have seen competing reactors, including the U.S. government’s National Ignition Facility (NIF), making headlines. Notably, NIF recently reached a milestone where its reactor core generated more energy than it consumed.