Nuclear energy is one of the widely used energy sources. Nuclear energy is obtained by conversion of the nuclear mass into equivalent energy which is calculated by the formula E=m*c^2. Nuclear energy is obtained by the nuclear fusion or nuclear fission reaction. Nuclear energy is released by exothermic process.
It is the splitting of the nucleus of an atom into parts of free neutrons and other smaller nuclei. In fission process tremendous amount of energy is produced. Nuclear fission is used in the nuclear weapons. The amount of free energy contained in nuclear fuel is millions of times than that in similar mass of chemical fuel. The products of nuclear fission are radioactive and are harmful for living things.
In nuclear power station only one neutron is released and allowed to strike for splitting another nucleus, for controlling of the chain reaction purposes.Nuclear energy is produced by a controlled chain reaction and crates heat which is used to produce steam and drive steam turbines which are coupled to the generator.
Nuclear fusion occurs between two isotopes of a lighter elements which are forced together at extremely high temperature until they fuse to form a heavier nucleus releasing enormous energy. The deuterium - tritium fusion reaction is considered the most promising for producing fusion power. They combine to create an unstable helium-5 nucleus. Two hydrogen atoms may fuse to form the nucleus of Helium at 1 billion degree C and release a huge amount of energy. Nuclear fusion occurs naturally in stars.
Today only nuclear fission is used not fusion. Fusion requires very high temperature which is quite impossible at present. Thus fusion cannot be used for energy conversion. Nuclear fusion occurs naturally in stars.