A star is born in Daejeon as Korea leads in the fusion race
DAEJEON — A giant metallic donut could yield the secrets of eternal energy.
Inside the vessel, housed in an anonymous concrete room in Daejeon and hooked up to a tangle of pipes and cables, hydrogen is heated to 100 million degrees Celsius (180 million degrees Fahrenheit) to achieve fusion.
It's an artificial sun. And it has been run in tests for a full 30 seconds, a record. No other fusion reactor has ever maintained plasma for that long.
In theory, such a device will be able to produce cheap, nearly pollution-free, stable power. In reality, that will not be possible for decades. If ever.
“When I started researching nuclear fusion 30 years ago, experts said that we’re going to need 30 years for mankind to successfully generate electricity from nuclear fusion,” said Yoon Si-woo, deputy director general of the Korea Superconducting Tokamak Advanced Research (Kstar) reactor, the experimental fusion reactor.
“We still say that we’re going to need 30 years."
The idea of fusion goes back a century, and since the 1950s, harnessing the science for peaceful purposes has been attempted by many nations. Breakeven, where more energy is produced than is used to contain the reaction, has never been achieved.
Much of the research has been focused on the shape of the vessel, and spheres, diabolically irregular stellarators and tokamak donuts, which became the standard, were tried. Hydrogen has to be contained by magnets as the atoms fuse, and the configuration of the container is key.
Korea's Kstar reactor, in operation since 2007, is a tokamak with a difference. Built by the Korea Institute of Fusion Energy (KFE), it utilizes Nb3Sn, an intermetallic compound made of niobium and tin and a superconductor.
The Kstar reactor is the first fusion reactor to be built with superconductors, giving Korea a competitive edge over other countries. No other project has been able to contain the super-hot plasma for more than 15 seconds.
Other tokamaks have used copper, which is also a good conductor but not as energy-efficient as niobium-tin.
“The ingredient for the Kstar reactor's quick success was the Nb3Sn superconductors,” Yoon said.
Korea has been working on fusion since 1995.
In July 2008, the Kstar reactor succeeded in artificially generating plasma. In 2018, the plasma reached 100 million degrees Celsius for the first time. Last year, with the superconductors, the Kstar reactor maintained the plasma at over 100 million degrees Celsius for 30 seconds.
The project is aiming for 50 seconds this year and 300 seconds by 2026, which according to Yoon is “the milestone for 24-hour operation” needed for generating power.
The goal is to contain the material stably and around the clock by 2050.
The dream energy
Fusion, which powers stars, is considered the ideal source of energy. The fuel is abundant — primarily from seawater. The process generates negligible pollution and far less radioactive waste than fission, and fusion reactors would be far less dangerous than existing nuclear reactors. Meltdowns are not possible; if the plasma escapes, fusion stops.
With only a bathtub of seawater and a lithium battery big enough to run a laptop, a working reactor would be able to generate the same amount energy as burning 40 tons of coal.
Fusion has gained considerable attention in recent years. The Fukushima disaster and efforts to reduce carbon emissions have many countries and companies scrambling for clean energy sources, and fusion is coming back into fashion due to its potential to meet demand without the hidden costs and dangers of other alternatives.
Given the new priorities, the funding needed to make fusion a reality could be raised, and working reactors are now more of a possibility than ever.
"Climate change is a big issue, and the fusion program is gaining a lot of interest, with more to come in the coming years,” Yoon said. "The situation has changed, and we are bringing the 30 years closer to reality."
In addition to the superconductors, the Korean project is utilizing other technologies that could help bring the fusion energy dream closer to fruition.
It is developing a lithium breeding blanket, a “blanket” of lithium filled with deuterium — hydrogen with one neutron — which can be transformed into tritium — hydrogen with two neutrons — when it meets the neutrons that are emitted as a byproduct of nuclear fusion.
Deuterium and tritium fuse more easily than hydrogen with no neutron, and tritium can generate 1,000 times more energy than deuterium. While deuterium can be found in seawater, tritium doesn’t exist in nature.
If the lithium breeding blanket is developed, then a fusion reactor can have a self-sustaining tritium supply that can keep it running with just deuterium.
Other upgrades and innovations are planned that will help Kstar reach its goals.
“We are going to start a renovation of the Kstar reactor in March to upgrade the tokamak with more heat-resistant metal, from carbon-based material to tungsten,” Yoon said. “There are things we need to prove, but we are also going to work them out along the way to hit the 300-second target in 2026.”
Kstar received 43.2 billion won ($36.3 million) from the government in 2021 and will get 42.5 billion won this year. A total of 418.2 billion was used to construct the reactor.
Globally, from Kurchatov, Kazakhstan to Princeton, New Jersey, more than 20 tokamaks and 10 stellarators are operational, while a dozen of the former and half a dozen of the latter have been abandoned.
Due to the costs and risks of fusion development, cooperation is seen as one way to cross the last and most difficult mile of research, and one massive multinational project is already underway.
The International Thermonuclear Experimental Reactor (ITER) is a fusion reactor being built at Saint-Paul-lès-Durance. France, and 35 nations, including Korea, are taking part in the project.
The tokamak will have a radius of 6.2 meters, making it the world's largest nuclear fusion reactor when it is completed in 2025.
If all goes according to plan, by 2035, it will achieve "burning plasma," where it creates more energy than is used, and participants will take the technology back to their home countries for use in their own fusion developments.
ITER will be utilizing the same niobium-tin superconductors used in Kstar.
Korean companies that have joined in building Kstar are also taking part in ITER, including Hyundai Heavy Industries, SFA Engineering, Hyundai Mobis and SeAH Changwon Integrated Special Steel.
As of last December, Korean companies were awarded 161 contracts related to the ITER project, worth 686.8 billion won.
“Fusion is not only a dream but is now becoming a real energy source,” said Yoo suk-jae, president of KFE.
“If this becomes a reality, then the source of funding could also diversify. Big companies like Amazon and people like Bill Gates could even take an interest. I have very optimistic views, if we can get the plasma under control.”
BY YOON SO-YEON [email@example.com]