Let’s learn about ‘Nuclear Fusion’ and its importance
Population growth, urbanization and expanding access to electricity in developing countries increased the demand for energy from the past couple of decades. So, there is a need to find an energy source which is sustainable and carbon-free to secure our future generations and the planet Earth. In the words of UK Atomic Energy Authority “Bringing the power source of the stars down to the Earth could give us low carbon electricity for Millenia to come”
All the energy that is produced comes from basic chemical and physical processes. Fission and Fusion are two physical processes that produce massive amounts of energy from atoms.
Fission occurs by splitting a larger atom into two or more smaller atoms. When each atom splits, a tremendous amount of energy is released. Uranium and plutonium are most commonly used for fission reactions in nuclear power reactors because they are easy to initiate and control.
Fusion Process:
Fusion occurs by joining two or more atoms into a larger. A nuclear fusion reaction can occur when two atomic nuclei approach very close to each other at velocities at least large enough to overcome their mutual electrostatic repulsion called “Coulomb barrier”. This is the same process that powers the sun and creates huge amounts of energy which is several times greater than fission. Fusion of light nuclei to form a heavy nucleus releases a large amount of energy.
Energy is produced in the sun and stars by the following continuous fusion reactions. Let’s look more into this natural phenomenon. Four nuclei of hydrogen fuse in a series of reactions to yield one nucleus of helium and protons. The energy corresponding to the change to the in mass is calculated from Einstein’s law. The energy released per nuclear reaction will be 25.7 MeV. The heat produced in these reactions maintains temperatures of the order of several million degrees in the cores of the sun and stars which serves as sustainable succeeding reactions.
Technology to recreate on Earth:
If the controlled fusion of light elements is carried out on our planet, enough energy can be generated to meet all the energy requirements of future generations. Fusion research is indeed being taken seriously by the major industrial nations. There are serious efforts by individual countries as well as combined effort by consortium of countries.
In order to produce energy from fusion on Earth, a combination of hydrogen gases — deuterium and tritium — are heated to very high temperatures (over 100 million degrees Celsius). The gas becomes a plasma and the nuclei combine to form a helium nucleus and a neutron, with a tiny fraction of the mass converted into fusion energy. A plasma with millions of these reactions every second can provide a huge amount of energy from very small amounts of fuel. One way to control the intensely hot plasma is to use powerful magnets. The most advanced device for this is the ‘tokamak’, a Russian word for a ring-shaped magnetic chamber. Added a bit more about this in Fusion research, references-3.
Advantages of Fusion 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. 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, Fusion doesn’t emit harmful toxins like carbon dioxide or other greenhouse gases into the atmosphere. Its major by-product is helium which is a non-toxic gas. 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
Famous quote by Stephen Hawking “I would like Nuclear Fusion to become a practical power source. It would provide an inexhaustible supply of energy, without pollution or global warming”
Fusion Research: The following information is taken from Reference 3
ITER- In 1985, International Thermonuclear Experimental Reactor (ITER( is collaborated by Soviet Union, Europe, Japan and the USA. Later in 1992 ,Canada and Kazakhstan partnered as well.
JET- In 1978, the European Community (Euratom, along with Sweden and Switzerland) launched the Joint European Torus (JET) project in the UK. JET is the largest tokamak operating in the world today.
Tokamak Energy: Tokamak Energy is a private company in UK.
KSTAR: The KSTAR (Korean Superconducting Tokamak Reactor) at the National Fusion Research Institute (NFRI) in Daejeon produced its first plasma in mid-2008. It is a pilot device for ITER, and involves much international collaboration
EAST: In China the Experimental Advanced Superconducting Tokamak (EAST) at China Academy of Sciences’ Hefei Institutes of Physical Science (HFIPS) produced hydrogen plasma at 50 million degrees Celsius and held it for 102 seconds in 2017
TFTR: In the USA, the Tokamak Fusion Test Reactor (TFTR) operated at the Princeton Plasma Physics Laboratory (PPPL) from 1982 to 1997.d In December 1993, TFTR became the first magnetic fusion device to perform extensive experiments with plasmas composed of D-T. The following year TFTR produced 10.7 MW of controlled fusion power — a record at that time.
References:
1. https://generalfusion.com/what-are-the-benefits-of-fusion-energy/
