Fission and Fusion Energetics

• If we split a nucleus of mass A = 230 into two masses of A = 115. From the figure in last frame, BE/Nucleon for A=230 is 7.5MeV and the same for A=115 is 8.4 MeV. Hence the reaction will release energy equal to 0.9 x 230 = 217 MeV.
• Thus fission process releases a large amount of energy.
• Similarly if two light elements fuse to become a heavy element, energy would be released as the product nuclei has a higher binding energy than the reactants.
• Though fusion energy release per reaction is less, but specific energy (energy release per unit
  mass) is high.
• While the curve indicates possibility of energy release, ways and means have to be found
  to enable the reactions to take place.

Fission Energetics

• Consider the following equation

• Binding Energy of Last Neutron is (BELN) 6.6 MeV.
• Energy necessary to be supplied to induce fission is called Critical Energy for Fission.
• The critical energy for fission and BELN for some isotopes are summarised in the following table.