Mechanism of fission: In the fission process, the heavy nucleus absorbs a neutron and forms an unstable compound nucleus. The compound nucleus then breaks up more or less in the middle to give fission product. It is defines as Mechanism of Fission.
A typical example of the fission process in the fission of uranium by neutrons is explained by the following equation.
92U235 + 0n1 → 56Ba141 + 3 0n1 + 200 MeV
Further, the neutrons released (say three) from the fission of first uranium atoms can hit three other uranium atoms. In this way a chain reaction is set up resulting into the liberation of an enormous amount of energy. In the case of nuclear fission, 92U236 formed breaks up in several ways.
This fission process is self multiplying process and hence a tremendous amount of energy is released in a very short interval of time. Therefore, explosion takes place. Atom bomb is based on nuclear fission process.