Nuclear fission and fusion are two different nuclear reactions. Both involve changes in atomic structure, but they work in different ways, produce different amounts of energy, and have different uses.

1. What They Are

• Nuclear Fission: This is when a heavy nucleus breaks apart into two or more smaller nuclei. This process releases energy and neutrons. Common materials that can undergo fission are Uranium-235 and Plutonium-239.

• Nuclear Fusion: This happens when two light atomic nuclei join together to form a heavier nucleus. This process also releases a lot of energy. In stars, isotopes of hydrogen like Deuterium and Tritium are the main fuels for fusion.

2. Changes in Atomic Structure

• In Fission:

  • Fission is usually started by a neutron being absorbed by the heavy nucleus. This causes the nucleus to change shape and eventually split. The smaller nuclei that form can have different atomic masses and numbers.
  • The smaller nuclei, called fission products, are often radioactive. This means they can be dangerous and need to be carefully handled. For example, Cesium-137, a fission product, has a half-life of about 30 years.

• In Fusion:

  • Fusion requires really high temperatures (around 1 to 10 million degrees Kelvin) and high pressures. This is necessary to overcome the natural repulsion between positively charged nuclei.
  • When the fusion happens, hydrogen nuclei combine to make Helium, and energy is released. According to Einstein’s equation (E=mc^2), a fusion reaction can release about 17.6 million electron volts (MeV) for each reaction of Deuterium and Tritium.

3. Energy Production

• Fission:

  • Each fission event releases about 200 MeV of energy. When Uranium-235 undergoes fission, it usually releases about 2.5 neutrons. Those neutrons can then cause more fission reactions, creating a chain reaction.

• Fusion:

  • Fusion is very efficient in producing energy. For example, using just 1 kilogram of fusion fuel can produce about 8 million times the energy that burning 1 kilogram of fossil fuel would provide.

4. Uses

• Fission:
  • Fission is commonly used in nuclear power plants, generating nearly 10% of the world's electricity. However, it also creates long-lasting radioactive waste that needs careful disposal.
• Fusion:
  • Fusion isn’t yet practical for widespread use, but it has the potential to be a nearly unlimited and clean source of energy. Scientists are focused on finding ways to control fusion, like using Magnetic Confinement Fusion, with designs called Tokamaks.

Conclusion

Both fission and fusion are powerful ways to produce energy. They involve significant changes in atomic structure, but their processes, the products they create, and their potential uses are very different. This shows us the unique principles of nuclear chemistry.