KSTAR, South Korea’s nuclear fusion research facility, continues to break its own records and take steps to realize a new type of power generation to help solve the world’s energy and environmental challenges.
The milestone achieved at the end of last year is difficult to understand for someone who is not familiar with nuclear fusion: the huge device kept active a flow of plasma with ions at a temperature of 100 million degrees Celsius for 30 seconds.
But it is better understood if it is explained that this temperature is what is required to replicate on earth what happens inside the stars.
This type of extreme conditions is basically what KSTAR, which can be defined as an “artificial sun”, tries to recreate so that in the future the multinational ITER program can carry out the same process by which the sun produces and releases huge amounts of energy.
In addition to South Korea, ITER, which will be an “artificial sun” more complex and 27 times larger than KSTAR when its construction is completed in the south of France, is made up of the European Union, China, the United States, Russia, India, Japan, Switzerland and the United Kingdom and will begin operations in 2025.
The road to fusion
“Fusion energy is more than a dream,” said Yoo Suk-jae, president of the Korea Fusion Energy Institute (KFE), which is responsible for KSTAR, at a meeting with foreign journalists this week at its Daejeon headquarters. 130 kilometers south of Seoul.
“The crucial moment may come in 2035, when ITER could begin to generate fusion in a self-sufficient way,” Yoo added, reviewing the calendar handled by the sector and which contemplates, if ITER is successful, the possibility that a fusion reactor could generate electricity by 2050.
What KSTAR, and by extension ITER, are looking for is that this possible future reactor can, through a magnetic confinement system, maintain two isotopes of hydrogen, deuterium and tritium, in a plasma state, so that their nuclei can fuse.
If this technology becomes a reality, one gram of deuterium and tritium will be capable of generating the equivalent of what a ten tons of coal produces.
Key to the energy mix
Yoon Si-woo, deputy general manager of the KSTAR Research Center, believes that fusion “may be an important element in the energy mix of the future.”
Fusion does not emit gases into the atmosphere, the radioactive waste it generates is negligible compared to current nuclear fission plants and, as Yoon points out, “the fuel (deuterium and tritium) is abundant in seawater.”
But to make this type of energy a reality, it is essential, in addition to the creation of a self-sufficient fuel circuit that regenerates and recycles tritium, the stabilization of the plasma on which KSTAR is working.
The machine is housed in the central building of the complex in Daejeon and its main body, which houses the superconducting magnets and the annular plasma vacuum chamber, measures almost 9 meters high and almost 9 meters wide.
Yoon goes on to detail its various components and highlights challenges such as the fact that the magnets inside the device have to work at the same time, which have to be “very very cold” for superconductivity to occur, and the plasma chamber, which must be ” very very hot.”
“Separated by only three or four meters there is a part that has to be at about 4 degrees kelvin (about 270 degrees Celsius below zero) and another that has to exceed a million degrees Celsius,” he says.
Asked about the records that China’s EAST experimental reactor also broke in 2021, including operating on the electrons (not ions) of plasma at 120 million degrees Celsius for 101 seconds, Yoon points out that these achievements are actually complementary to ITER. .
“The world records thing is a good thing. We motivate each other,” he explains, noting that there is an annual meeting between the two neighboring countries to collaborate on magnetic confinement fusion.
For this year, he notes, KSTAR’s goal is, with an even higher plasma density, to keep the ions at 100 million degrees for 50 seconds with an eye toward increasing that time to 300 seconds by 2026.
Among the challenges to achieve these goals is to further stabilize the plasma flow, increase its temperature and pressure, and improve the diffusion of the tremendous heat emitted by the machine through a new tungsten pipe that will be installed soon.
“When I first learned about nuclear fusion, my university professor told me: ‘It’s going to take 30 years to develop fusion.’ And here I am now, saying the same thing: there would still be about three decades to go,” Yoon laughs.
“But one thing has changed. ITER is growing fast. It is an important milestone, and due to climate change there is going to be a lot more interest in this field. So stay tuned,” he says. EFE