nuclear fission and fusion

• Nuclear fission


  The splitting of the nucleus of a large, unstable element like uranium or plutonium
• Nuclear fission


  • Can happen spontaneously but normally requires the nucleus to absorb a neutron first
  • The nucleus splits to form two smaller 'daughter' nuclei
  • Emits 2-3 neutrons and gamma radiation
  • Releases a large amount of energy
• Nuclear fission chain reaction


  1. Neutrons emitted can be absorbed by other nuclei, triggering more fission

  2. This creates a self-sustaining chain reaction releasing large amounts of energy
• Controlled nuclear fission


  Used in nuclear reactors to generate electricity
• Uncontrolled nuclear fission


  Causes the explosion in a nuclear weapon
• Nuclear fusion


  The joining of two light nuclei, like hydrogen, to form a heavier nucleus, releasing energy
• Nuclear fusion is the process that releases energy in stars like the Sun
• Nuclear fusion is not a chain reaction, unlike nuclear fission