At the end of the year that saw the start of machine assembly of the International Thermonuclear Experimental Reactor (ITER), or the world’s largest nuclear fusion project, being assembled in France to replicate the fusion power of the sun to enable generation of clean unlimited energy, South Korea’s magnetic fusion device Korea Superconducting Tokamak Advanced Research (KSTAR) set a new record by reaching the temperature of over 100 million degrees Celsius for a period of 20 seconds.
It was announced last month that in late November 2020, the KSTAR Research Center at the Korea Institute of Fusion Energy (KFE), in a joint research with the Seoul National University (SNU) and Columbia University of the US, had succeeded in continuous operation of plasma for 20 seconds with an ion temperature higher than 100 million degrees. In comparative terms, KSTAR was able to attain 6.6 times the temperature of the Sun, which radiates at a temperature of only 15 million degrees Celsius.
Referred to as South Korea’s “artificial Sun”, KSTAR had achieved a similar feat also in 2018, but the temperature then could only be maintained for one and a half seconds. In 2019, the device repeated its performance and retained the temperature for a period of 8 seconds, setting a new record thereby, and increasing the duration over its previous plasma operation by more than two times. Previously, other fusion devices that managed plasma at temperatures of 100 million degrees or higher were unable to maintain the operation for 10 seconds or longer. Earlier, it has been difficult to maintain a stable plasma state in the fusion device at such high temperatures for a long time.
In its 2020 experiment, the KSTAR managed to improve the performance of its Internal Transport Barrier (ITB) developed last year, and succeeded in maintaining the plasma state for a longer period, overcoming the existing limits of the ultra-high temperature plasma operation.
KSTAR Research Center Director Si-Woo Yoon said in a statement: “The technologies required for long operations of 100 million- plasma are the key to the realization of fusion energy, and the KSTAR’s success in maintaining the high-temperature plasma for 20 seconds will be an important turning point in the race for securing the technologies for the long high-performance plasma operation, a critical component of a commercial nuclear fusion reactor in the future.”
The KSTAR has a target to increase the plasma operation performance to 300 seconds by the year 2025. The ITER machine being assembled at Cadarache in France expects to generate the first ultra-hot plasma in late 2025. The world’s largest science project is intended to demonstrate that fusion power can be generated on a commercial scale.
ITER will be the first project to achieve a self-heating plasma and is expected to generate 10 times more heat than is put in. Fusion provides clean, reliable energy without carbon emissions, with minute amounts of fuel and no physical possibility of an accident with meltdown.The fuel for fusion is found in seawater and lithium, while it is abundant enough to supply the world for millions of years. A football-sized amount of this fuel is equivalent to around 10,000 tons of coal.
The plant at ITER will produce about 500 MW of thermal power. If operated continuously and connected to the electric grid, that would translate to around 200 MW of electric power, which is sufficient for the average needs of 200,000 homes. A commercial fusion plant will be designed with a slightly larger plasma chamber, for 10-15 times more electrical power. For instance, a 2,000 MW fusion power plant could supply electricity to two million homes.
Tokamak (derived from the Russian words for “toroidal magnetic confinement”) devices, originally developed in Russia, are used to recreate fusion reactions that occur in the Sun. According to the Institute for Radiation Protection and Nuclear Safety (IRSN), there are about 250 tokamak devices around the world.
Last month, the China National Nuclear Corporation (CNNC) announced that it had switched on its ‘artificial Sun’, which managed to operate at 150 million degrees Celsius. In November 2018, the Institute of Plasma Physics in Hefei, China, had announced that an Experimental Advanced Superconducting Tokamak (East) device had reached a milestone temperature of 100 million degrees Celsius and heating power of 100 MW.