New milestone in producing Nuclear Fusion Energy

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    • Recently, Scientists in the United Kingdom achieved a new milestone in producing nuclear fusion energy or imitating the way energy is produced in the Sun

    About 

    • A team at the Joint European Torus (JET) facility near Oxford in central England generated 59 megajoules of sustained energy during an experiment in December, more than doubling a 1997 record.
      • A kg of fusion fuel contains about 10 million times as much energy as a kg of coal, oil or gas.
    • The energy was produced in a machine called a tokamak, a doughnut-shaped apparatus.
      • Deuterium and tritium, which are isotopes of hydrogen, are heated to temperatures 10 times hotter than the centre of the sun to create plasma. 
        • This is held in place using superconducting electromagnets as it spins around, fuses and releases tremendous energy as heat.
    • Earlier research: 
      • In August 2021, scientists at the Lawrence Livermore National Laboratory in the U.S. reported generating 1.3 megajoules in 100 trillionths of a second from fusion in an alternative approach to a tokamak by focussing 192 giant lasers onto a pea-size pellet of hydrogen.
    • Significance 
    • Energy by nuclear fusion is one of mankind’s long-standing quests as it promises to be low carbon, safer than how nuclear energy is now produced and, with an efficiency that can technically exceed 100%.
    • It offers so much potential to address the effects of climate change.
    • The prospect of fusion energy is deeply attractive because it does not release greenhouse gases and 1kg of fusion fuel contains about 10m times as much energy as 1kg of coal, oil or gas.
    • The record and scientific data from these crucial experiments are a major boost for the International Thermonuclear Experimental Reactor(ITER).

    ITER (International Thermonuclear Experimental Reactor)

    • It is the world’s largest fusion experiment.
    • It was launched in 1985 and is located in France.
    • It aims to build the world’s largest tokamak to prove the feasibility of fusion as a large-scale and carbon-free source of energy. 
    • The ITER Members—China, the European Union, India, Japan, Korea, Russia and the United States—are now engaged in a 35-year collaboration to build and operate the ITER experimental device, and together bring fusion to the point where a demonstration fusion reactor can be designed.
    • The member states share the cost of project construction, operation and decommissioning and they also share the experimental results and any intellectual property generated by the fabrication, construction and operation phases.

    What is Nuclear Fusion?

    • Nuclear Fusion is the process wherein lighter atoms combine to form heavier atoms accompanied by the release of energy.
    • This process powers the Sun and other stars, whereby they generate heat and light.
    • On Earth, it is achieved by combining two isotopes of Hydrogen i.e deuterium and tritium.
    • Process: 
      • The Deuterium (H-2) and Tritium (H-3) atoms are combined to form Helium (He-4), the next element in the periodic table. A free and fast neutron is also released as a result.
      • The neutron is powered by the kinetic energy converted from the ‘extra’ mass left over after the combination of lighter nuclei of deuterium and tritium occurs.

     Image Courtesy: theguardian

    • How is it achieved? 
      • In a Nuclear Fusion Reactor, The two atomic nuclei are brought very close to each other, activating the nuclear forces which act as a ‘glue’ for the nuclei and overcoming the electrostatic forces that repel similarly charged atomic nuclei.
    • Required conditions: 
      • This requires high density, high-temperature conditions to create a plasma state (the fourth state of matter), in which electrons are stripped away from atomic nuclei to form ionized gas. 
      • The electrostatic forces can be overcome when this state is achieved and the process can be controlled via magnetic confinement in nuclear fusion reactors.

    Advantages of Nuclear Fusion

    • Abundant energy: Fusing atoms together in a controlled way releases nearly four million times more energy than a chemical reaction such as the burning of coal, oil or gas and four times as much as nuclear fission reactions (at equal mass). 
    • Sustainability: Fusion fuels are widely available and nearly inexhaustible.
      • Deuterium can be distilled from all forms of water, while tritium will be produced during the fusion reaction as fusion neutrons interact with lithium.
    • No CO?: Fusion doesn’t emit harmful toxins like carbon dioxide or other greenhouse gases into the atmosphere. Its major by-product is helium: an inert, non-toxic gas.
    • No long-lived radioactive waste: Nuclear fusion reactors produce no high activity, long-lived nuclear waste. The activation of components in a fusion reactor is low enough for the materials to be recycled or reused within 100 years.
    • Limited risk of proliferation: Fusion doesn’t employ fissile materials like uranium and plutonium. (Radioactive tritium is neither a fissile nor a fissionable material.) There are no enriched materials in a fusion reactor like ITER that could be exploited to make nuclear weapons.
    • No risk of meltdown: It is difficult enough to reach and maintain the precise conditions necessary for fusion—if any disturbance occurs, the plasma cools within seconds and the reaction stops.

    How Is Nuclear Fission Different ?

    • Nuclear fission is the splitting of a massive nucleus into photons in the form of gamma rays, free neutrons, and other subatomic particles. In a typical nuclear reaction involving 235U and a neutron.
    • Fission produces many highly radioactive particles.
    • The energy released by fission is a million times greater than that released in chemical reactions; but lower than the energy released by nuclear fusion
    • One class of nuclear weapons is a fission bomb, also known as an atomic bomb or atom bomb.

    Image Courtesy:EIA

    Source: TH