The nuclear reaction in which two light nuclei merge to form a heavy nucleus is called fusion reaction. The energy released per nucleon is 0.91 MeV. It is due to the reality that binding energy per nucleon is greater than Uranium.
Fusion reactions are most easily attained with hydrogen atoms because of the low coulomb barrier and favorable wave mechanical transmission element. The quantum mechanical tunnel effects allow the reaction to proceed at an appropriate rate at lower temperatures.
The fusion reaction that requires the lowest energy and, hence, the most readily attainable combination procedure in the Earth, is the combination of a deuterium nucleus with one of tritium.
The products of such a fusion reaction are a 3.5 MeV helium ion (α particle) and a 14.1 MeV neutron, described as a fusion neutron. On the Earth, to produce net power, fusion reactions need to occur at very high temperatures of a minimum of 100 million degrees, which is some seven times hotter than the center of the Sun. At this high temperature, the fusion fuel develops into a plasma.
Nuclear Fusion reactions power the Sun and other stars. In a fusion reaction, 2 light nuclei combine to form a single much heavier nucleus. The process releases energy because the overall mass of the resulting single nucleus is less than the mass of the two initial nuclei. The remaining mass becomes energy.
Einstein’s equation (E= mc2), which states in part that mass and energy can be converted into each other, discusses why this process takes place. If scientists develop a way to harness energy from the blend in machines in the world, it could be an essential approach to energy production.
Types of Nuclear Fusion Reactions
The two nuclear reactions now most typically utilized for power production purposes are designated as DD and D-T reactions. The former stands for deuterium-deuterium and involves the mix of two deuterium nuclei to form a helium-3 nucleus and a totally free neutron.
The 2nd reaction stands for deuterium-tritium and includes the mix of a deuterium nucleus and a tritium nucleus to produce a helium-4 nucleus and a free neutron.
When 2 deuterons combine to form a helium nucleus 24 MeV energy is released throughout this reaction.
21 H + 21 H à42 He + 24 MeV
However, there is very little chance of development of 42 He nucleus by the combination of two deuterons.
The possibility of this reaction to occur is more when one proton or one neutron is produced such as this:
21 H + 21 H à31 H + 11 H + 4.0 MeV
21 H + 21 H à32 He + 10 n + 3.3 MeV
In both of these reactions about 1.0 MeV energy per nucleon is produced which amounts to the energy produced during fission.
If 21 H and 32 H are required to fuse then 1.76 MeV energy is produced.
21 H + 32 H à42 He + 10 n + 1.76 MeV
Methods for Producing Fusion Reaction
The major obstruction to fusion is the Coulomb repulsion between nuclei. To produce a fusion between two nuclei work has to be done to conquer these repulsive forces. For this purpose, two nuclei are moved towards one another at a very high speed.
By using accelerator
The accelerator provides the nuclei with a very large velocity. This technique is utilized to study nuclear fusion of 21 H and 31 H. However, this is not useful for getting energy at a large scale.
By increasing temperature
The speed of atoms of a compound increases with an increase in the temperature of the substance. To produce a nuclear fusion reaction, a temperature of about 10 million Celsius is needed. The place where a reaction occurs at this temperature is called a thermonuclear reactor. The energy to begin the reaction is obtained by the surge of a Hydrogen bomb.
The Sun produces energy by fusing protons or hydrogen nuclei 1H (by far the Sun’s most plentiful nuclide) into helium nuclei 4He. The principal series of fusion reactions form what is called the proton-proton cycle.
The general result of the cycle is 26.7 MeV consists of the annihilation energy of the positrons and electrons and is dispersed among all the reaction products. The solar interior is thick, and the reactions occur deep in the Sun where temperatures are greatest. It takes about 32,000 years for the energy to diffuse to the surface and radiate away.
Negative feedback in the Sun functions as a thermostat to control the overall energy output. Stars like the Sun are steady for billions of years, up until a substantial fraction of their hydrogen has been diminished.