Forms of Energy > Nuclear Energy

Energy is released when nuclei undergo reactions (fission or fusion) that move them from a state of lower total binding energy to a state of higher total binding energy.

The splitting of a heavy nucleus into lighter nuclei, releasing energy.

The combination of light nuclei to form a heavier nucleus, releasing energy.

The binding energy per nucleon curve shows that both very light and very heavy nuclei have less binding energy per nucleon than nuclei in the middle of the periodic table.

• When nuclei move from a less stable state (lower total binding energy) to a more stable state (higher total binding energy), energy is released.
• This energy release occurs in:
  Fission of heavy nuclei
  Fusion of light nuclei

The following facts are directly from the source material:

• Flat (stable) region: Mass number A = 30 to A = 170
• Value in this region: Approximately 8.0 MeV per nucleon
• Outside this region: Binding energy per nucleon is less than 8.0 MeV
  This applies to lighter nuclei (A < 30)
  This also applies to heavier nuclei (A > 170)

Region-wise Summary Table