| Nuclear fission | Nuclear fusion |
| 1. In this process heavy nucleus is divided into two fragments along with few neutrons. | 1.In this process lighter nuclei will join together to produce heavy nucleus. |
| 2. These reactions will takes place even at room temperature. | 2. These reactions will takes place at very high temperature such as 106 °C |
| 3. To start fission at least one thermal neutron from out side | 3. No necessary of external neutrons. |
| 4. Energy released per unit mass of participants is less. | 4. Energy released per unit mass of participants is high. Nearly seven time more than fission reaction. |
| 5. In this process neutrons are liberated. | 5. In this process positrons are liberated. |
6. This reaction can be controlled.
Ex : Nuclear reactor. | 6. There is no control on fusion reaction. |
| 7. Atom bomb works on principle of fission reaction. | 7. Hydrogen bomb works on the principle of fusion reaction. |
8. The energy released in fission can be used for peaceful pur– pose.
Ex : Nuclear reactor and Atomic power stations. | 8. The energy released in fusion cannot be used for peaceful purpose. |
