Artificial city

Chinese artificial sun breaks record by hitting 120 million francs in nuclear fusion race

Researchers bringing about the nuclear process that powers stars on Earth to meet humanity’s growing energy needs have broken a major record in the generation of superheated plasma.

The team at China’s ‘artificial sun’ fusion facility – the Advanced Experimental Superconducting Tokamak (EAST) – said that on December 30, 2021, it was able to generate plasma at 120 million degrees Fahrenheit (approx. 70 million degrees Celsius) and hold it for 1056 seconds.

In its 15 years of operation, EAST, operated by the Chinese Academy of Sciences (ASIPP), has achieved these temperatures and confinement time before, but never jointly, making it a milestone in fusion.

Gong Xianzu, researcher at ASIPP, said, “We reached a plasma temperature of 120 million degrees Celsius (216 F) for 101 seconds in an experiment during the first half of 2021. This time, the operation of the plasma steady-state was maintained for 1056 seconds at a temperature near 70 million degrees Celsius, laying a solid scientific and experimental basis for the operation of a fusion reactor. “

Tokamaks, like the donut-shaped EAST reactor, are often referred to as “artificial suns” because they are devices that mimic the fusion processes that occur in stars. These processes provide the energy radiated by these stellar bodies, and researchers here on Earth aim to deliver this energy in a controlled manner to power our homes and cities.

If scientists are successful in bringing this process to Earth, fusion energy could provide the world with a safe, sustainable, environmentally friendly, and abundant source of energy that would be an alternative to fission nuclear power.

The fusion process is almost the opposite of the fission process that powers the current generation of nuclear power plants in that, rather than separating atoms of heavy elements, it forces atoms of light elements to create atoms. heavier.

In the super hot plasma – a gas of ionized atoms – that makes up stars, intense gravitational pressure forces the hydrogen atoms together at high speed to form helium.

A single helium atom does not have as much mass as two hydrogen atoms and this difference in mass is released as energy which is radiated by the stars.

To reproduce this stellar process, tokamaks must heat heavy hydrogen atoms (deuterium and tritium) with lasers to temperatures of up to hundreds of millions of degrees Fahrenheit while confining this plasma in strong magnetic fields.

The temperature of the plasma in tokamaks must be higher than that of stars, where fusion processes occur at around 60 million degrees F. Indeed, Earth-related scientists cannot replicate the intense pressure generated by the gravity at the heart of a star.

This means compensating by heating the plasma to around 270 million degrees Fahrenheit, the temperature at which the atomic nuclei of a tokamak will break apart quickly enough to initiate nuclear fusion.

Additionally, to actually generate usable fusion energy, tokamaks must contain the plasma they generate and hold it at these temperatures long enough for the atomic nuclei to begin to break together and the process to be self-sustaining.

Researchers at EAST say they are working towards this goal, as do scientists from other tokamaks like the Korea Fusion Energy Institute’s Korean Superconducting Tokamak Advanced Research Reactor (KSTAR).

KSTAR set a world record in 2016 by maintaining superheated ionic gas of 90 million F for 70 seconds. EAST broke this record the following year by sustaining a 90 million F plasma for 102 seconds.

In 2021, EAST broke this record again by maintaining plasma at around 216 million F for around 101 seconds. This new development breaks the record for holding overheated plasmas by maintaining plasma for more than ten times longer, albeit at a lower temperature.

Fusion is considered a cleaner process than fusion because it does not create any radioactive waste, the end product of the fusion process being helium. In addition, the fuel it consumes consists of light and abundant materials like deuterium, rather than expensive, rare and dangerous elements, like uranium or plutonium used in smelters.

Theoretically, these fuels can be obtained in large quantities from seawater, one liter of water being estimated by some experts as sufficient to provide sufficient raw material for smelting to produce the energy equivalent to the combustion of 300 liters. of oil.

(Left) China’s donut-shaped tokamak EST reactor. (Left) A stunning image of the sun captured by NASA.
Institute of Plasma Physics / Chinese Academy of Sciences / NASA