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Brain-booster / 27 Mar 2022

Brain Booster for UPSC & State PCS Examination (Topic: Nuclear fusion breakthrough)

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Why in news?

  • Scientists in the United Kingdom have managed to produce the largest amount of energy so far from a nuclear fusion reaction. This result is being seen as a major breakthrough in the ongoing global efforts to produce a fusion nuclear reactor.

Nuclear Fusion

  • In a nuclear fusion reaction two lighter nuclei combine to form a relatively heavier nucleus.
  • In this process huge amount of energy is also released.
  • Temperature at which protons would have enough energy to overcome the coulomb’s barrier is very high.

Thermonuclear fusion

  • Increasing the temperature of the material until the particles have enough energy due to their thermal motions alone to overcome the coulomb barrier.
  • For thermonuclear fusion, extreme conditions of temperature and pressure are required.
  • Example of Thermonuclear fusion is generation of energy in stars.

Energy Generation in Sun

  • The mass of one hydrogen atom is 1.007825 Atomic Mass unit (AMU).
  • When four hydrogen atoms are combined, it transmutes into a helium atom.
  • The sum of the mass of four hydrogen atoms is 4.03130 AMU, while the mass of one helium atom is just 4.00268 AMU.
  • As we know, matter is neither created nor destroyed; hence the mass difference 0.02862 AMU is converted into pure energy by way of Einstein’s famous formula E=mc2
  • Final reaction is:- 411H +2e- --> 42He +6 γ+2 ν+26.7MeV
  • It is also known as proton-proton cycle because this process starts with protons.

Recent Advancement

  • China’s Experimental Advanced Superconducting Tokamak (EAST) sustained the plasma at 70 million degrees Celsius for 1,056 seconds in January 2022.
  • In February 2022, the Joint European Torus (JET) fusion experiment in Oxfordshire, U.K., produced 59 megajoules (MJ) of energy from thermonuclear fusion.

About Tokamak

  • For fusion to occur, the first step has to be the creation of hot plasma.
  • Heating a tiny pellet of hydrogen to millions of degrees and generating plasma is not that hard; lasers could do the job well.
  • To keep the fiery plasma at millions of degrees from touching the container wall is the main task
  • Soviet physicists Igor Tamm and Andrei Sakharov conceptualised that if one can create a magnetic field in the shape of a torus, then the scorching plasma could be contained in the invisible magnetic bottle.
  • Based upon this theory, an experimental reactor was built and demonstrated by a Soviet team led by Lev Artsimovich at the Kurchatov Institute, Moscow.
  • The Tokamak is an acronym for tonguetwisting Russian terms ‘toroïdalnaïa kameras magnitnymi katushkami’, which means “toroidal chamber with magnetic coils”.
  • Despite alternative designs having been designed and tested, tokamaks are far ahead for achieving fusion.
  • 35 countries, including India, Russia, USA, UK, China, EU, are collaborating to jointly build the largest Tokamak as part of the International Thermonuclear Experimental Reactor (ITER).
  • In 2035, the plant is expected to generate 500 MW power and consume 50 MW for its operation, resulting in a net 450 MW power generation.
  • None of the tokamaks worldwide, has demonstrated net energy production more than the input.

Significance of the recent accomplishment

  • The plasma at high temperature needs to be sustained for a long time if commercial energy has to be obtained.
  • The Chinese accomplishment of maintaining 2.8 times the Sun’s temperature for 17 minutes is a milestone in this direction.
  • The JET experiment could harvest onethird of the input energy as an output, a significant step from earlier results.