Nuclear Fusion and Nuclear Fission

Nuclear fusion

Fusion is a reaction in which two or more nuclei combine to form subatomic particles (neutrons or protons) with one or more different nuclei. The mass difference between the reactants and the product manifests itself as either energy release or uptake. This difference in mass is caused by the nuclear binding energy between the nuclei before and after the reaction. Fusion is the process of powering main sequence stars, main-sequence stars, and other high-grade stars and releasing large amounts of energy.

The release of energy from the fusion of light elements is due to the interaction of two opposing forces: the nuclear force that binds protons and neutrons and the Coulomb force that repels protons from each other. The protons are positively charged and repel each other by Coulomb force, but they can still stick to each other, indicating the existence of another short-range force called nuclear attraction. 

Light nuclei (or nuclei smaller than iron or nickel) are small enough that the nuclear force lacks protons to overcome the repulsion. This is because the nuclei are so small that all nucleons feel at least a short-range gravitational pull as an infinite distance Coulomb repulsion. When you build a nucleus from a light nucleus by fusion, extra energy is released from the net attraction of the particle. However, for larger nuclei, no energy is released because the nuclear force is short-range and cannot continue to act on a longer nuclei length scale. Therefore, no energy is released during such fusion. Instead, such processes require energy as input.

Nuclear Fission

Fission is the reaction in which the nucleus of an atom splits into two or more small nuclei. Fission processes often produce gamma photons and emit very large amounts of energy, even by the energy standard of radioactivity. Fission is a form of transmutation because the resulting fragment (or daughter atom) is not the same element as the original parent atom. The two (or more) nuclei produced are mostly equivalent but slightly different in size, and the mass ratio of common fissile isotope products is usually about 3: 2. Most fission is bifurcation (producing two charged fragments), but occasionally (2-4 times per 1000 events), trisection produces three positively charged fragments. The smallest of these fragments in the ternary process ranges in size from protons to argon cores.

Difference between nuclear fusion and nuclear fission

Nuclear fusion

• Two cores connect to form a heavier core

• There is no chain reaction

• The light core needs to be heated to a very high temperature

• Scientists are still working on a nuclear fusion reactor that has been controlled. There is no nuclear waste

• The raw materials are very accessible. The energy density of fusion reactions is many times higher than that of fission

Nuclear fission

• Heavy nuclei collapse to form two light nuclei
• This is a chain reaction that can lead to a dangerous meltdown
• Heavy cores are bombed with neutrons
• There are established, decades-old techniques for controlling fission
• Nuclear waste, a by-product of nuclear fission, is an environmental problem
• Raw materials such as plutonium and uranium are rare and expensive

Conclusion 

If you want to know where the difference lies, you must take a closer look. Nuclei of atoms are not elementary and indivisible. They have two parts, protons and neutrons. For understanding nuclear fission or fusion, you must examine the bonds between these components. There are nuclear forces that bind the protons and neutrons together. There are other powers as well. For example, the electric force that all protons repel each other because they all have the same charge. Related to all these forces is the so-called binding energy. This is the energy that needs to be provided to decompose proton and neutron clusters or to overcome the electrical repulsion between the two protons.