China’s EAST Reactor: Advancing Magnetic Fusion Technology

Sub: Sci

Sec: Nuclear

Why in News

On January 20, 2025, Chinese scientists successfully maintained plasma at a temperature of 100 million degrees Celsius for 1,066 seconds in the Experimental Advanced Superconducting Tokamak (EAST) reactor. This breakthrough is significant for the progress of ITER (International Thermonuclear Experimental Reactor), a global nuclear fusion megaproject that has faced delays and cost overruns.

Nuclear Fusion:

Nuclear fusion occurs when two atomic nuclei fuse, releasing a tremendous amount of energy.
Unlike nuclear fission, which generates harmful radioactive waste, fusion is considered a clean and sustainable energy source.
Achieving sustained nuclear fusion could revolutionize global energy production by providing an abundant and environmentally friendly power source.

Challenges in Achieving Nuclear Fusion:

The Tritium Problem: Deuterium-tritium fusion is the most feasible reaction due to its lower temperature requirement compared to deuterium-deuterium fusion.
Deuterium is abundant in seawater, but tritium is scarce and must be produced artificially in heavy-water reactors in Canada, India, and South Korea.
The Temperature Barrier: To achieve fusion, the required temperature exceeds 100 million degrees Celsius, which is significantly higher than the Sun’s core temperature (15 million degrees Celsius).

Tokamak Technology: Achieving Magnetic Confinement

A tokamak is a doughnut-shaped (toroidal) reactor where a plasma state is achieved by heating deuterium gas to extreme temperatures.
Inside EAST, magnetic fields created by superconducting electromagnets confine the plasma and keep it from touching the reactor walls.
EAST is the only tokamak in the world with both toroidal and poloidal magnetic fields, enhancing its ability to maintain plasma stability.
2016: Sustained high-confinement plasma at 50 million degrees Celsius for 60 seconds.
2017: Extended the plasma duration to 100 seconds.
2023: Set a world record by maintaining high-confinement plasma for 403 seconds.
2025: Surpassed its previous record by sustaining plasma for 1,066 seconds, demonstrating improved stability and efficiency.
EAST does not yet produce electricity as it has not achieved ignition, meaning the fusion process is not yet self-sustaining.
ITER and other fusion projects aim to achieve a net energy gain, where the energy output exceeds the energy input.

Alternative Fusion Technologies:

Stellarator: A stellarator is a type of nuclear fusion device designed to confine hot plasma using complex, twisted magnetic fields to sustain controlled nuclear fusion reactions.
- Magnetic Confinement: Utilizes external magnets arranged in a helical configuration to create a twisted magnetic field, effectively confining the plasma without the need for inducing electric currents within the plasma itself.
Laser-inertial fusion: It is also known as inertial confinement fusion (ICF), is a method where nuclear fusion reactions are initiated by rapidly compressing and heating small fuel pellets using high-energy laser beams.
- Fuel Pellet Compression: A small spherical pellet containing deuterium and tritium is targeted by multiple high-powered laser beams from all directions.
- The intense laser energy compresses the pellet to extremely high densities and temperatures, creating conditions necessary for nuclear fusion to occur.
- The National Ignition Facility (NIF) in the US achieved fusion ignition in 2022, a milestone not yet reached by tokamak reactors.

International Thermonuclear Experimental Reactor (ITER):

ITER is one of the most ambitious energy projects in the world today.
In southern France, 35 nations are collaborating to build the world’s largest tokamak, a magnetic fusion device that has been designed to prove the feasibility of fusion as a large-scale and carbon-free source of energy based on the same principle that powers our Sun and stars.
The ITER Members China, the European Union, India, Japan, Korea, Russia and the United States have combined resources to conquer one of the greatest frontiers in science.
As signatories to the ITER Agreement, concluded in 2006, the seven Members will share of the cost of project construction, operation and decommissioning.
They also share the experimental results and any intellectual property generated by the fabrication, construction and operation phases.

Hydrogen and Its Isotopes:

Protium: The most common isotope, consisting of one proton and no neutrons. It is stable and constitutes the majority of hydrogen found naturally.
Deuterium: Contains one proton and one neutron in its nucleus. Accounts for approximately 0.0156% of natural hydrogen. Used in nuclear fusion research, as a tracer in scientific studies, and in heavy water moderated fission reactors.
Tritium: Consists of one proton and two neutrons. Radioactive with a half-life of about 12.32 years, decaying into helium-3. Produced in nuclear reactors and utilized in fusion research, as well as in self-luminous devices.