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Breakthrough In Fusion Energy


For the first time, scientists in the United States have achieved a net gain in energy from a nuclear fusion reaction.


GS Paper 3: Science and Technology- developments and their applications and effects in everyday life.

Mains Question

Consider nuclear fusion energy as a potential source of clean energy in the near future. (250 words)

Reactions to Nuclear Fusion:

  • Nuclear fusion reactions provide energy to the Sun and other stars.
  • A fusion reaction occurs when two light nuclei combine to form a single heavier nucleus.
  • Because the total mass of the resulting single nucleus is less than the mass of the two original nuclei, the process releases energy. The remaining mass is converted into energy.
    • Albert Einstein’s equation, E=mc2, explains why this process occurs in part by stating that mass and energy can be converted into each other.
  • The Sun is a massive nuclear fusion reactor; if scientists can harness it, it will provide a near-limitless source of clean energy. Because hydrogen and helium make up the majority of the Sun’s composition, nuclear fusion takes place primarily between them.

Difference Between Fission and Fusion:

  • Fission:
    • Fission occurs when a neutron collides with a larger atom, causing it to excite and split into two smaller atoms—also known as fission products.
    • A tremendous amount of energy is released when each atom splits.
    • Uranium and plutonium are the most commonly used fission fuels in nuclear power reactors because they are simple to start and control.
    • The fission energy released in these reactors heats water into steam. To generate carbon-free electricity, steam is used to spin a turbine.
  • Fusion: When two atoms collide, they fuse to form a heavier atom, such as when two hydrogen atoms fuse to form one helium atom.
    • This is the same process that powers the Sun and generates enormous amounts of energy—many times more than fission.
  • Scientists are studying fusion reactions, but they are difficult to sustain for long periods of time due to the enormous amount of pressure and temperature required to join the nuclei together.

How is Fusion superior to Fission?

  • Fission and fusion both use the binding energy of protons and neutrons in atom nuclei to release massive amounts of energy.
  • The most serious issue with fission is that some of its byproducts are radioactive for years and must be disposed of in special facilities.
    • Additionally, reactor accidents, such as those at Three Mile Island in 1979 and Chernobyl in 1986, can release radioactive material into the environment.
  • Nuclear fusion reactors require only abundant hydrogen and can be built anywhere, unlike fission reactors, which require rare radioactive substances such as uranium.
  • Furthermore, the amount of energy produced by fusion is enormous — four times that of nuclear fission reactions — and fusion reactions can serve as the foundation for future fusion power reactors.
  • Once fusion energy is commercialised, the world will be able to generate nearly carbon-free electricity with no radioactive byproducts.

Why is it so difficult to achieve Fusion Energy?

  • The Sun’s massive gravitational force naturally induces fusion; however, without that force, the reaction requires a higher temperature to occur.
    • To make nuclear fusion work on Earth, we need temperatures exceeding 100 million degrees Celsius, intense pressure, and sufficient confinement to hold the plasma and maintain the fusion reaction long enough for a net power gain.
  • While conditions very similar to those required in a fusion reactor are now routinely achieved in experiments, improved confinement properties and plasma stability are required.
    • For the first time, scientists in the United States have achieved a net gain in energy from a nuclear fusion reaction.
  • Simply put, this is the first time a fusion reaction has generated more energy than it consumes.

The significance of this breakthrough is as follows:

  • Fission-based power plants have been around since the 1950s, and India has a number of them.
    • However, scientists have been working for years to develop a nuclear fusion reactor, which is marketed as a clean, abundant, and safe source of energy.
    • Net energy gain has been elusive because fusion occurs at such high temperatures and pressures that it is extremely difficult to control.
  • The success of researchers at the Lawrence Livermore National Laboratory in California, USA, can be viewed as a significant step forward in the decades-long effort to master a technology that is regarded as the most reliable source of energy in the future.

November 2023