Atomic Structure: Nuclear Fission

Atomic Structure: Nuclear Fission

Nuclear Fission

• Nuclear fission is the process wherein the nucleus of an atom splits into two smaller nuclei.
• The process usually involves heavy, unstable isotopes such as Uranium-235 or Plutonium-239.
• The atom to be split is usually bombarded with a neutron to initiate the fission process.

Nuclear Fission and Energy Release

• During nuclear fission, a large amount of energy is released, much greater than what is released during chemical reactions.
• This released energy forms the basis of nuclear power and nuclear weapons.
• It’s worth mentioning that in nuclear fission, in addition to the two smaller formed nuclei (fission products), typically a few spare neutrons and gamma photons are also emitted.

Chain Reactions in Nuclear Fission

• The spare neutrons released during nuclear fission can cause further fission in other nuclei, creating a chain reaction.
• Chain reactions can be either controlled or uncontrolled.
• Controlled chain reactions are used in nuclear power plants, whereas uncontrolled chain reactions form the basis for nuclear weapons.

Nuclear Fission Reactors

• A nuclear fission reactor contains a nuclear fuel (usually Uranium-235 or Plutonium-239), a moderator to slow down the neutrons, and control rods to absorb neutrons and control the chain reaction.
• The energy generated in a fission reactor is used to heat water, creating steam, which drives turbines to generate electricity.
• A cooling system is crucial in a fission reactor to remove excess heat and prevent overheating.

Key Takeaways

• Nuclear fission involves the splitting of a heavy, unstable nucleus into two smaller nuclei, releasing a large amount of energy.
• The spare neutrons released during fission can trigger further fissions, creating a chain reaction.
• Nuclear fission reactors, which control these chain reactions, are a source of nuclear power.