Nuclear Chain Reaction Process and Nuclear Fission Process

NUCLEAR CHAIN REACTION PROCESS:

In nuclear chain reaction process, a heavyweight isotope generally uranium-235 is used for a nuclear chain reaction. Uranium-235 is natural and it will give higher fission percentage too. Some other fissionable materials (U-233, PU-239) are present in the world. But U-235 is the most common isotope to use for a nuclear chain reaction. Because it produces comparatively higher amount of energy and heat from the other fissionable materials. One of the most common nuclear chain reaction process is: ²³⁵₉₂U + ¹₀n = ¹³⁹₅₆Ba + ⁹⁴₃₆Kr + 3 ¹₀n

In the above reaction, it is shown that a heavy nucleus uranium-235 strikes one neutron and it produce alternative three neutrons. These three neutrons again strikes U-235 which produce nine neutrons and striking nine neutrons produce another twenty-seven neutrons and so on, showing in the picture:

In each reaction, neutrons are released with the multiplication of three and this reaction is continuously running until original nuclei are fission. A single fission reaction generates a large amount of energy, so the complete nuclear chain reaction process will generate many times greater energy. Though all neutrons are not used nuclear chain reaction. Some of these neutrons are lost to the surroundings. If this reaction is not controlled, it will produce explosive violence’s. The working principle of atom bomb blasting is an uncontrolled nuclear chain reaction process.

NUCLEAR FISSION PROCESS:

Nuclear fission process is the most practical method used in all modern fission reactors. Nuclear chain reaction is not possible without this process. A heavy nucleus is split into two or more smaller nuclei, is called nuclear fission process. This is a very basic defination of a nuclear fission process. When a heavy-weight nucleus like²³³₉₂ or ²³⁵₉₂U or ²³⁹₉₄9U is bombarded with high-energy particles such as protons, neutrons or X rays, a large amount of energy is released for this reaction. Generally, neutrons are used for this process. Because it is natural and it does not hold any charge. So it can easily make their way to electrons. Here is an example:

²³⁵₉₂U + ¹₀n = ¹³⁹₅₆Ba + ⁹⁴₃₆Kr + 3 ¹₀n + Energy

This reaction was discovered by Hahn and Strassmann in the year 1939. Generally Uranium-235 is used for nuclear Fission Process.It is a fissionable material and also it is used all modern nuclear reactors .

In the above picture, a heavy atomic nucleus uranium-235 is bombarded with single neutrons and produces two nuclei. First uranium will be an unstable ‘compound nucleus’ to absorb neutrons. The radioactive atom of any nucleus is unstable for continuous emission of an alpha() or bita() particles. This will change the proton-neutron composition of the nucleus to built a stable nucleus. U-235 will be an unstable nucleus when it absorbs a neutron. This unstable nucleus will be split into two daughter nuclei (i.e. ²³⁵₉₂U and ⁹⁴₃₆Kr) with some neutrons and release a large amount of energy. It is seen that one fission reaction of ²³⁵₉₂U release nearly 200 MeV of energy.

200MeV energy: 200 X 1.6 X 10^-13 = 3.2 X 10^-11joules (or watt-seconds)

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