Nuclear Energy

Nuclear binding energy

Binding energy is the energy required to separate a nucleus into its constituent nucleons. It is related to the nucleus’s mass defect through E = Δmc².

Binding energy per nucleon helps explain why both fusion of light nuclei and fission of very heavy nuclei can release energy.

→ Nuclear binding energy

Nuclear fission

In nuclear fission a heavy nucleus divides into lighter nuclei, usually with neutrons and substantial released energy.

Some fission events can release neutrons able to trigger further fissions, which is the physical basis of a chain reaction.

→ Nuclear fission

Nuclear fusion

Fusion joins light nuclei into heavier nuclei. When the products are more tightly bound, the difference in binding energy can be released.

Fusion powers main-sequence stars, but achieving controlled fusion on Earth requires extreme conditions and careful confinement.

→ Nuclear fusion

Mass-energy equivalence

Einstein’s relation E = mc² expresses the equivalence of mass and energy. In reactions, a change in total rest mass corresponds to a change in energy.

Nuclear reactions make this especially visible because small mass differences can correspond to substantial energies.

→ Mass-energy equivalence

Sources

IUPAC Gold Book · NIST · BIPM