Fission and Fusion

Basic Principles

Fission is a nuclear process where a heavy nucleus splits into two or more smaller nuclei. This is usually accompanied by the release of a significant amount of energy.
Fusion is the reverse process of fission, where two or more light nuclei combine to form a heavier nucleus. This process also releases energy, often even more than fission.

Fission is the principle behind the operation of nuclear power plants and the explosion of atomic bombs.
Fusion, under controlled conditions, is currently being explored as a viable and potentially limitless source of power. Fusion is the process that fuels stars, including our sun.

Fission generally involves heavy, unstable isotopes, such as Uranium-235 or Plutonium-239.
Fusion usually involves light, stable isotopes such as Hydrogen-2 (Deuterium) and Hydrogen-3 (Tritium).
Fission often produces highly radioactive waste due to the unstable fission products.
Fusion theoretically produces less radioactive waste, as the main product is stable Helium.

In fission, a neutron is used to initiate the reaction by striking a heavy nucleus, causing it to split.
In fusion, high temperatures and pressures are needed to overcome the electrostatic repulsion between the light nuclei.
Chain reaction is a term associated with fission where the neutrons produced in one reaction can trigger subsequent fissions, creating a self-sustaining reaction.
In the sun, fusion occurs in a series of reactions known as the proton-proton chain, where protons merge to form helium.
While fusion has the potential for a nearly inexhaustible supply of energy, the challenge lies in harnessing the reaction as it requires extremely high temperatures akin to the conditions inside a star.