Nuclear Fusion Reaction at National Ignition Facility

In News

• Recently, the Lawrence Livermore National Laboratory in an experiment at its National Ignition Facility has made a breakthrough in nuclear fusion research. 

About The Experiment

• They have been able to produce 1.3 megajoules of energy at its National Ignition Facility.
• They applied laser energy on fuel pellets to heat and pressurise them at conditions similar to that at the centre of our Sun. This triggered the fusion reactions.
• These reactions released positively charged particles called alpha particles, which in turn heated the surrounding plasma.
• At high temperatures, electrons are ripped from an atom’s nuclei and become a plasma or an ionised state of matter. Plasma is also known as the fourth state of matter.
• The heated plasma also released alpha particles and a self-sustaining reaction called ignition took place. 
• Ignition helps amplify the energy output from the nuclear fusion reaction and this could help provide clean energy for the future.
• Significance:
  • It will allow physicists to probe the conditions in some of the most extreme states in the universe, including those just minutes after the Big Bang.
  • To gain insights into quantum states of matter.

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: Philadelphia

• 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.

Source: IE