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

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.

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.

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.

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.

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.

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.

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.