Before starting with what is nuclear fission or fusion or nuclear reactors or anything else, you should know the concepts of nuclear energy.
All matter is made of tiny atoms. All atoms have a nucleus at their core, where most of their mass is concentrated. In specific circumstances, it is possible for this nucleus to undergo certain changes. Nuclear fusion (as the name suggests) is a process of combining small atoms, resulting in heavier atoms with more energy. Nuclear fission is splitting of the nucleus of a heavier atom into a smaller one. Both these processes release a tremendous amount of energy. And how does that happen?
Remember Einstein’s famous equation E = mc2 ?
E is energy
m is mass
c is the speed of light in vacuum
Although the mass in consideration is really small, the speed of light is a large number (299792458 m/s). When this potential was realized it led to the field of harnessing nuclear energy (literally the energy in the nucleus).
The good thing about nuclear energy is that it has the potential to generate a lot of energy/power without any emission of pollutants. The only disadvantage is the disposal of nuclear waste has to be done extremely carefully.
When the nucleus of an atom splits into lighter nuclei through a nuclear reaction the process is termed as nuclear fission. This decay can be natural (spontaneous splitting by radioactive decay), or can actually be simulated in a lab by achieving necessary conditions (bombarding with neutrinos).
The resulting fragments tend to have a combined mass which is less than the original. The missing mass is what is converted into nuclear energy in the above reaction.
An example of nuclear fission is the splitting of Uranium-235. The equation of the reaction has been given below.
Stay tuned with byju’s to know more about nuclear fission, nuclear energy and much more.