Nuclear fission + fusion

• Nuclear fission

  The nucleus of large, unstable elements like uranium and plutonium split
• Nuclear fission

  1. Nucleus absorbs neutron

  2. Nucleus splits into two smaller nuclei (daughter nuclei)

  3. Emits 2-3 neutrons + gamma radiation

  4. Releases energy
• Neutrons emitted in fission

  Can be absorbed by more uranium nuclei, triggering more fission
• Chain reaction

  A huge number of uranium nuclei undergo fission in a very short time, releasing enormous energy
• Controlled fission chain reaction

  Used to generate electricity in nuclear reactors
• Uncontrolled fission chain reaction

  Causes explosions in nuclear weapons
• Nuclear fusion

  Two light nuclei, like hydrogen, join 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