nuclear fission and nuclear fusion

Difference between nuclear fission and nuclear fusion

Nuclear Fission Nuclear Fusion
When a heavy nucleus like U-235 splits up into nearly two equal parts by the bombardment of slow-moving neutrons considerable amount of energy is released. When two or more lighter atoms of hydrogen or protons are fused into heavier atom, a large amount of energy is released.
The principle behind atom bomb is Nuclear fission. The principle behind the hydrogen bomb is nuclear fusion.
In this reaction, 200 MeV of energy is released per fission. In this reaction 25.71 MeV of energy is released.
Energy released per nucleon is less. The energy released per nucleons is more.
Particles involved are neutrons Particles involved are protons.
Fission takes place at room temperature. Fusion takes place only at very high temperature and high pressure.
Fission produces radioactive elements like Barium and Krypton which are harmful (radioactive) The products of fusion are harmless (not radioactive)