Last Update: June 2025 (Nuclear Fusion)
Nuclear Fusion
This article deals with ‘Nuclear Fusion .’ This is part of our series on ‘Science and Technology’, which is an important pillar of the GS-3 syllabus . For more articles, you can click here.
Introduction
- In a Nuclear Fusion reaction, two small atoms (usually isotopes of hydrogen, like Deuterium and Tritium) combine to form a bigger atom (Helium) and release enormous energy.
- Nuclear Fusion needs very high energy and can be carried at 10^7 K temperature (such a high temperature is challenging to achieve & even more challenging to maintain)
How Does Fusion Work?
- Fusion reactors aim to replicate the conditions of the Sun using a technology called Tokamak to carry out Nuclear Fusion.
- A Tokamak is a doughnut-shaped (toroidal) chamber designed to replicate the Sun’s fusion process under controlled laboratory conditions. Here’s how it works:
Steps of Nuclear Fusion using Tokamak Technology
Step 1: Creating Plasma
- Hydrogen gas is heated to temperatures exceeding 150 million degrees Celsius, converting it into plasma – a superheated, electrically charged state of matter.
Step 2: Magnetic Confinement
- Since no material can contain such extreme heat, powerful magnetic fields (created by superconducting magnets) are used to hold the plasma in place without touching the walls. These magnetic fields form a magnetic “cage” to confine and stabilize the plasma.
Step 3: Fusion Reaction
- Inside the Tokamak, Deuterium and Tritium nuclei collide at high speeds.
- If they come close enough, the strong nuclear force overcomes repulsion, and they fuse to form Helium and a high-energy neutron.
Real-World Tokamak Projects
1. ITER (International Thermonuclear Experimental Reactor)
- Location: Cadarache, France
- 35 nations, including India, are part of it.
- Largest Tokamak ever built.
- Goal: Produce 10 times more energy than input (50 MW in, 500 MW out).
- Timeline: Commercial viability expected by 2050.
2. China’s EAST (Artificial Sun)
- Simulates the Sun’s fusion process.
- Surpassed 1,000 seconds of sustained fusion in Jan 2025.
3. Aditya Tokamak
- India’s own Tokamak at the Institute for Plasma Research, Gujarat.
- It is part of India’s independent fusion program.
Challenges in Achieving Controlled Nuclear Fusion
Despite decades of research, controlled nuclear fusion remains an engineering challenge due to:
- Extremely High Temperature: The reactor must reach temperatures higher than the Sun’s core to achieve fusion.
- Handling Plasma: At such temperatures, matter exists as plasma, which can’t touch any surface. It must be suspended using strong magnetic fields, which are difficult to maintain.
- Electrostatic Repulsion: Nuclei resist coming close due to Coulombic repulsion. Achieving collision conditions is very difficult.
- Material Limitations: The reactor walls must withstand intense heat and radiation without degrading.
- Instability: Even minor changes in magnetic fields can destabilize plasma containment.
- Sustaining Reaction: Even if ignition is achieved, maintaining the reaction long enough to extract energy is tough.
Advantages of Nuclear Fusion
- Abundant Energy: Energy released is millions of times more than fossil fuels.
- Sustainability: Fuel sources (Deuterium & Tritium) are abundant and can be extracted from water and lithium.
- Zero CO₂ Emissions: Environmentally friendly—only helium is released.
- No Chain Reaction: Fusion is self-limiting. Hence, there is no chance of a meltdown.
- Low Proliferation Risk: Fusion doesn’t use fissile material like uranium or plutonium.
- Minimal Waste: No long-lived radioactive waste is generated.
Why Nuclear Fusion is Better than Nuclear Fission?
| Criteria | Nuclear Fission | Nuclear Fusion |
| Waste | Produces radioactive waste | No long-lived radioactive waste |
| Fuel | Uranium or Plutonium | Deuterium |
| Risk | Meltdown risk high | No meltdown risk |
| Pollution | Emits radioactive waste | No radioactive waste or harmful gases |
| Efficiency | Lower than fusion | Higher than fission |
Conclusion
Nuclear Fusion has the potential to revolutionize clean energy. Although practical implementation is decades away, recent breakthroughs bring hope. For UPSC aspirants, understanding fusion vs. fission, tokamak, and India’s initiatives is vital from Science & Tech, Environment, and Current Affairs perspectives.