Context: The Experimental Advanced Superconducting Tokamak (EAST), commonly known as China's "artificial sun," has achieved a remarkable milestone by maintaining steady-state high-confinement plasma operation for over 1000 seconds.
Relevance of the Topic: Prelims: Key facts about Experimental Advanced Superconducting Tokamak; Magnetic Confinement; International Thermonuclear Experimental Reactor (ITER).
Background: What is Nuclear Fusion?
- Nuclear Fusion is the process of combining two or more nuclei to form a heavier nucleus and release high-energy radiation. Nuclear fusion is what produces the energy in the Sun, or any other star.
- Fusion occurs naturally in stars where the high temperature at the core allows for the nuclei to overcome the repulsive electromagnetic force and fuse together.
- E.g., Combination of hydrogen nuclei to form helium, releasing energy in the form of neutrinos, gamma rays, and positrons.
What is the advantage of Fusion Reactors?
- Fusion reactors are increasingly seen as the future of energy security due to following factors:
- Abundance of fuel (Hydrogen in the form of water in oceans).
- Clean source of energy as it involves no release of carbon dioxide.
- Minimal nuclear waste.
- Two main factors to achieve fusion reaction: Fuel and Extreme Conditions for fusion.
- A typical fusion reactor uses hydrogen as a fuel that is abundant in the water of the oceans.
- The main problem in fusion is that the hydrogen nuclei repel each other. However, electric repulsion between two hydrogen nuclei can be overcome by heating the hydrogen to temperatures of millions of degrees Celsius (plasma state).
- The real challenge is to maintain such extreme conditions inside a fusion reactor.
Tokamak Approach for Magnetic Confinement
1. Need for a Tokamak:
- Extreme conditions for Fusion:
- Fusion reactions require very high temperatures (hundreds of millions of degrees Celsius) i.e., higher than the temperatures in the Sun’s core.
- At such high temperatures, matter exists only in the plasma state (in which atoms get split into positively and negatively charged particles). But such hot plasma cannot be handled by or contained in any material.
- Within the reactor, this plasma needs to be kept suspended in a confined space, surrounded by very strong magnetic fields acting as walls.
- Charged particles respond to magnetic fields, and this property is used to guide the flow of plasma within an enclosed space, separated from any matter.
- This condition is necessary for facilitating fusion reactions. But it is extremely delicate and unstable, as the tiniest of changes in the magnetic field can disturb the whole set-up.
- Scientists have not been able to maintain these conditions for longer than a few seconds.
2. What is a Tokamak?
- Tokamak is a specific type of magnetic confinement device. It utilises powerful magnetic fields to confine extremely hot plasma (heated to millions of degrees Celsius), keeping it stable and away from the physical contact with reactor walls.
- Inside the Tokamak, light isotopes of hydrogen (Deuterium and Tritium) are heated and compressed to undergo nuclear fusion to release enormous amounts of energy.
Experimental Advanced Superconducting Tokamak
- Experimental Advanced Superconducting Tokamak (EAST) is an experimental nuclear fusion reactor located in China.
- The reactor was able to sustain/maintain its operational state for more than 1,066 seconds, or over 17 minutes, which is a new record.
- EAST did not carry out a fusion reaction or produce any electricity. The technology has not yet reached that stage.
- It managed to maintain plasma in a steady state of confinement for a long time, longer than it did previously (previous record >400 seconds achieved in 2023).
- It is a major step forward towards realising a fusion-based nuclear reactor in the near future.
- Real-life electricity-generating fusion reactors would require this state to be maintained for days at a stretch. Presently, nuclear energy is produced through reactors based on Nuclear fission technology.
International Thermonuclear Experimental Reactor (ITER):
- ITER is the largest fusion reactor that works on the basis of the Tokamak approach, launched in 1985.
- Location: Saint-Paul-les-Durance in southern France.
- Objective: To demonstrate the scientific and technological feasibility of controlled fusion for future commercial power generation.
- ITER is a joint collaboration of 35 countries, members include- India, China, Japan, South Korea, Russia, United States and European Union.
- ITER is designed to produce 500 MW of fusion power from 50 MW of input heating power.
- According to its current timeline, it would begin deuterium-tritium fusion reactions by 2039, producing 500 MW of fusion power.