China’s EAST Reactor and Nuclear Fusion | 20 Feb 2025

For Prelims: Tokamak, Nuclear fusion, Difference between Nuclear Fusion & Nuclear Fission. 

For Mains: Advantages of Nuclear Fusion, Challenges in Harnessing Nuclear Energy 

Source: TH 

Why in News? 

China’s Experimental Advanced Superconducting Tokamak (EAST) nuclear fusion reactor set a new milestone in nuclear fusion by sustaining plasma at 100 million°C for 1,066 seconds.  

  • This achievement advances the pursuit of clean and sustainable fusion energy for future energy security. 

Tokamak: A tokamak is an experimental device designed to generate energy through nuclear fusion.  

  • Inside the tokamak, the heat produced from the fusion of atoms is absorbed by the vessel’s walls.  
  • Similar to conventional power plants, this heat is then used to produce steam, which drives turbines and generators to generate electricity. 

What is Experimental Advanced Superconducting Tokamak (EAST)? 

  • About: 
    • EAST is an advanced nuclear fusion research facility located at the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) in Hefei, China. 
    • It became operational in 2006. 
  • Purpose: 
    • It aims to replicate the nuclear fusion process that powers the Sun, contributing to the development of sustainable energy (without any harmful radioactive waste). 
    • It is a part of the International Thermonuclear Experimental Reactor (ITER) initiative, which will be the world's largest fusion reactor when operational by 2035.  
      • The ITER, established in 1985, is a collaboration of 35 nations located in France. It aims to build the world’s largest tokamak to demonstrate the feasibility of fusion as a large-scale, carbon-free energy source. 
      • Its members include China, the European Union, India, Japan, Korea, Russia and the US. 
  • Working Mechanism: 
    • EAST is based on the nuclear fusion process, where deuterium and tritium nuclei (isotopes of hydrogen) fuse to form a helium nucleus, releasing a large amount of energy. 
    • Hydrogen fuel is heated to over 150 million°C to form a hot plasma (ionized gas). 
    • A strong magnetic field confines the plasma, preventing heat loss and enabling sustained fusion reactions. 
  • Achievements & Significance:  
    • EAST has achieved significant milestones such as sustaining plasma at 50 million°C for over 60 seconds (2016) and 100 seconds (2017), achieving steady-state high-confinement plasma for 403 seconds (2023). 
    • Despite these, EAST has yet to achieve ignition (self-sustaining fusion) or produce electricity.  
    • It serves as a testbed for ITER, a multinational project, including India and the EU, aimed at developing a tokamak capable of achieving net energy gain. 
Read More: Why is Prioritizing the Nuclear Energy Sector Crucial for India?  

What are Nuclear Reactions? 

  • About: A nuclear reaction is an interaction between two nuclear particles or two nuclei that results in the formation of new nuclei different from the original ones.  
    • Nuclear reactions can be classified into two main types: nuclear fission and nuclear fusion. 
  • Nuclear Fission: It is a reaction that occurs when an atom's nucleus splits into smaller nuclei, releasing energy. 
    • It can occur naturally (radioactive decay) or be induced in a lab by bombarding the nucleus with neutrons or other particles. 
    • The combined mass of the resulting fragments is less than the original nucleus, with the lost mass converted into energy. 
    • All commercial nuclear reactors operate on nuclear fission. 
  • Nuclear Fusion: It is the process where two light atomic nuclei combine to form a heavier one, releasing massive energy.  
    • This reaction occurs in plasma state (high-temperature & charged state of matter).  
    • The Sun and other stars are powered by fusion, requiring temperatures of around 10 million°C to overcome electrical repulsion between nuclei. 
    • The hydrogen bomb operates on thermonuclear fusion, with a fission bomb (uranium/plutonium-based) providing the initial energy to trigger the reaction. 

 

What are the Challenges in Achieving Nuclear Fusion Reaction? 

  • Extreme Temperature Requirements: Fusion requires temperatures exceeding those found at the Sun’s core (over 100 million degrees Celsius) to sustain fusion reaction.
  • Magnetic Confinement:  Maintaining the high-energy plasma in a stable state requires strong magnetic fields, as used in tokamak reactors, to prevent energy loss and sustain reactions. 
  • Tritium Scarcity: While deuterium is readily available in seawater, tritium is scarce and primarily obtained from specific nuclear fission reactions, raising concerns about long-term fuel supply. 
    • Current sources of tritium include heavy-water reactors in Canada, India, and South Korea, but ITER’s demands could exhaust global reserves. 
  • Ignition Milestone: A self-sustaining fusion reaction, where energy output exceeds energy input, remains a major goal yet to be achieved. 
  • Sustained Reactions: Currently, maintaining stable plasma conditions for prolonged periods remains a major challenge. 

Alternative Approaches to Fusion Energy: Apart from tokamaks, researchers are exploring other fusion methods. 

  • Stellarators: It offers a complex yet promising magnetic confinement method that eliminates the need for a poloidal field (a kind of magnetic field) in tokamak, though they are harder to build. 
  • Laser Inertial Fusion: It involves the use of high-power laser beams to compress a deuterium-tritium pellet, triggering fusion. The energy released can generate steam to drive turbines, producing electricity.

Drishti Mains Question:

Discuss the role of nuclear energy in achieving global decarbonization goals. What are the key advantages and challenges associated with nuclear energy as a clean energy source? 

UPSC Civil Services Examination, Previous Year Questions (PYQs) 

Prelims 

Q. The function of heavy water in a nuclear reactor is to (2011)

(a) Slow down the speed of neutrons 

(b) Increase the speed of neutrons 

(c) Cool down the reactor 

(d) Stop the nuclear reaction 

Ans: (a)

Mains

Q. With growing energy needs should India keep on expanding its nuclear energy programme? Discuss the facts and fears associated with nuclear energy. (2018)