Type of Nuclear Reactions Nuclear Fission / Fusion – UPSC Prelims

Nuclear Reactions:
  • A nuclear reaction is the process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides.
  • Thus, a nuclear reaction must cause a transformation of at least one nuclide to another.
  • Types:
    • Nuclear Fission:
      • The nucleus of an atom splits into two daughter nuclei.
      • This decay can be natural spontaneous splitting by radioactive decay, or can actually be simulated in a lab by achieving necessary conditions (bombarding with neutrons, alpha particles, etc.).
      • The resulting fragments tend to have a combined mass which is less than the original. The missing mass is usually converted into nuclear energy.
      • Currently all commercial nuclear reactors are based on nuclear fission.
    • Nuclear Fusion:
      • Nuclear Fusion is defined as the combining of two lighter nuclei into a heavier one.
      • Such nuclear fusion reactions are the source of energy in the Sun and other stars.
      • It takes considerable energy to force the nuclei to fuse. The conditions needed for this process are extreme – millions of degrees of temperature and millions of pascals of pressure.
      • The hydrogen bomb is based on a thermonuclear fusion reaction. However, a nuclear bomb based on the fission of uranium or plutonium is placed at the core of the hydrogen bomb to provide initial energy.