Context:
JT-60SA, world’s biggest experimental nuclear fusion reactor was inaugurated in Japan recently.
About JT-60SA:
- A tokamak designed to contain and control plasma heated to a staggering 200 million degrees Celsius.
- Joint initiative between – European Union and Japan
- Forerunner for under-construction International Thermonuclear Experimental Reactor (ITER).
What is a Tokomak?
- Tokamak is a magnetic fusion device designed to tap into the potential of fusion energy in large scale and carbon-free source of energy.
- It operates based on same principles that power the Sun and stars.
- Uses robust magnetic field to fuse hot plasma.
- Temperature range – over 150 million degrees Celsius (10 times hotter than Sun’s core).
- Applications – Generation of electricity etc.
About ITER:
- Aim –
- To demonstrate nuclear fusion as a clean green source of energy.
- To build the world’s largest tokamak
- Location – Southern France
- Collaboration between – 35 nations including China, EU, India, Japan, Korea, Russia and US.
Other similar initiatives:
- China’s Artificial Sun: The Experimental Advanced Superconducting Tokamak (EAST) device replicates the nuclear fusion.
- SST-2 tokamak – India’s experimental fusion reactor at the Institute of Plasma Research, Gujarat.
- Joint European Torus (JET) – project for opening the way to future nuclear fusion grid energy.
Basics about Nuclear Fusion
What is Nuclear Fusion?
- Process by which two light atomic nuclei (for example tritium and deuterium) combine to form a single heavier (Helium) one while releasing massive amounts of energy.
Where does it take place?
- It takes place in a state of matter called plasma – a hot, charged gas made of positive ions and free-moving electrons with unique properties distinct from solids, liquids, or gases.
Challenge to fusion –
- Strong repulsive electrostatic forces between the positively charged nuclei prevent them from getting close enough together to collide and for fusion to occur.
When does it happen?
- If the attractive nuclear force (which binds protons and neutrons together in atomic nuclei) between the nuclei outweighs the repulsive (electrostatic) force, then a fusion reaction can occur.
- Such conditions can occur when the temperature increases, causing the ions to move faster and eventually reach speeds high enough to bring the ions close enough together.
Conditions required to achieve fusion
- Temperature of more than 100 million degrees Celsius.
- Maintaining a high enough density for a long enough time so that the rate of fusion reactions will be large enough to generate the desired power.
Types of Nuclear Fusion –
- Inertial fusion: Laser or ion beams are focused very precisely onto the surface of a target. This results in very high temperatures.
- Magnetic fusion: Hundreds of cubic meters of plasma at a density of less than a milligram per cubic meter are confined by a magnetic field at high pressure and heated to fusion temperature.
It is relatively easier to attain break-even energy levels through inertial fusion compared to magnetic fusion.
Source: India Today
Must Read: Particle Accelerators
Previous Year Question
India is an important member of the ‘International Thermonuclear Experimental Reactor’. If this experiment succeeds, what is the immediate advantage of India?
[UPSC Civil Services Exam – 2016 Prelims]
(a) It can use thorium in place of uranium for power generation.
(b) It can attain a global role in satellite navigation
(c) It can drastically improve the efficiency of its fission reactors in power generation
(d) It can build fusion reactors for power generation
Answer: (d)
