Fission vs Fusion ✏ Chemistry In a Nutshell

Rucete ✏ Chemistry In a Nutshell

1. Nuclear Fission

• Definition: A large atomic nucleus splits into two or more smaller nuclei.

• Key Characteristics:

  • Causes element transformation (new elements form).
  • Produces free neutrons, photons, alpha (α) and beta (β) particles.
  • Occurs in heavy elements (e.g., uranium, plutonium).
  • Exothermic reaction (releases a large amount of energy).
  • Emits gamma rays and kinetic energy from nuclear fragments.

• Example Reaction (Uranium-235 Fission):

  $${}^{235}_{92}U + 1^0n → {}^{141}_{56}Ba + {}^{92}_{36}Kr + 3(1^0n) + \text{energy}$$

  (Uranium-235 absorbs a neutron and splits into Barium-141, Krypton-92, and three more neutrons, which can trigger further fission.)
  

2. Nuclear Fusion (핵융합)

• Definition: Two smaller atomic nuclei combine to form a larger, heavier nucleus.

• Key Characteristics:

  • Occurs in stars (e.g., the Sun).
  • Releases much more energy than fission.
  • Requires extremely high temperatures and pressure.
  • No radioactive waste (compared to fission).
  • Primary reaction in hydrogen bombs.

• Example Reaction (Hydrogen Fusion in the Sun):

  $${}^{1}_{1}H + {}^{1}_{1}H → {}^{2}_{1}H + e^+$$

  (Two hydrogen atoms fuse to form deuterium and a positron, continuing in a series of reactions to form helium.)

In a nutshell

Feature	Fission	Fusion
Process	Splitting of a heavy nucleus	Combining of light nuclei
Energy Released	Large	Much larger than fission
Common Fuel	Uranium-235, Plutonium-239	Hydrogen isotopes (Deuterium, Tritium)
Conditions Required	Can occur at room temperature (with neutron bombardment)	Requires extremely high temperature & pressure
Examples	Nuclear power plants, atomic bombs	The Sun, hydrogen bombs
Waste Production	Produces radioactive waste	Little to no radioactive wast