Nuclear Fusion | Fusion energy explained with Hydrogen atom example | Physics animation video In this video we will understand how to or more nucleons merge or fuse together to create something more powerful and meaningful. Let us first understand the meaning of the word NUCLEAR FUSION, Nuclear meaning the process which involves Nucleus and Fusion in English means two or more entities coming together or merging together to form one single entity. So, nuclear fusion can be simply defined as the fusion or Combination of Nuclei. Scientifically, Nuclear Fusion can be defined as a nuclear reaction, in which lighter nuclei are combined together to form heavier product nuclei with the release of enormous amount of energy. Lighter Nuclei such as Lithium and Helium when combined together form a Heavier Nucleus. The mass of heavier nucleus is less than the initial reacting nuclei. The word 'heavier' here is phrased in terms of energy released, which is usually enormous, rather than mass. Therefore the law of conservation of energy is satisfied. Consider the example of two hydrogen nuclei combining to form a deuterium. The chemical equation for this reaction is1 1H + 1 1H → 2 1H + 0 +1e + 00 v. Here, one Hydrogen atom combines with another Hydrogen atom giving Deuterium, one Positron and one Neutrino. This Deuterium in turn combines with another Hydrogen nucleus to form a Helium isotope. That is, 21H + 1 1H → 3 2He(Helium Isotope) If two such Helium isotopes are fused together, formation of heavier helium takes place. In other words, 3 2He + 3 2He → 4 2He + 21 1H These 3steps of nuclear process, where four protons are fused together to form a heavier 4 2He nucleus and enormous amount of energy is a nuclear fusion reaction. The chemical equation for this nuclear fusion is: 41 1H → 4 2He + 2 0+1e + 2 00v + Q which is the Energy emitted in the Fusion reaction. (4 protons when fused together give rise to 2 heavier nucleus, 2 positrons, 2 neutrinos and enormous energy.) But how is this enormous amount of energy being liberated from such a seemingly simple nuclear reaction. To understand this, let us first calculate the loss of mass in the process. The starting mass is that of four protons, that is 4 X 1.0078 = 4.0312amu, but the final mass of Helium nucleus is 2me= 4.001506amu. Therefore the loss of mass is 4.0312 - 4.001506 = 0.0297 amu. This is equivalent to an energy given by Q = (0.0297amu) X 931,5 Mev/amu =27.67 Mev. Wow......That is a significant energy release coming from the fusion of 4 protons. However, in spite of such substantial amounts of energy being released in nuclear fusion reactions, there are no full-time nuclear reactors built so far for fusion reaction as it is very hard to control such enormous energy released.

• published: 06 May 2013
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