Nuclear Fusion and Nuclear Fission

Nuclear fusion is a process in which two atoms or molecules of the same element or different elements fuse to form a larger molecule of the element or elements. The nuclei of the atoms or molecules are a little larger than the other atoms or molecules and carry a full charge. Fusion reactions involve a lot of energy. The more the process is carried out, the more energy is released. 

Nuclear fission is the process of splitting atoms in which two atoms are separated by a very thin wall of the nucleus that does not exist in nature; this wall is called a fissure. The fission of the nucleus could occur in two different ways, either by a collision of two nuclei or by the fission of a nucleus through an exothermic process.

Differences between Nuclear fission and Nuclear fusion:

Definition:

The bombardment of a large isotope (a heavy and unstable nucleus) by high-speed particles in order to break the isotope down into smaller fragments (nuclei) is called nuclear fission. 

On the other hand, the process of fusion (or combining) of two isotopes of the lower mass (light nuclei) under extreme pressure and temperature conditions is called nuclear fusion.

Energy Released:

In the process of fission, the energy is released in the form of heat and radiation and is used by nuclear reactors to heat water and produce electricity. 

In the process of fusion, the energy released is much more than the energy released during nuclear fission. The energy released during the nuclear fusion is too high to control, and hence, it is not used for the production of power. Both of these processes are exothermic.

Energy Required:

A very little amount of energy is required for the fission reactions, whereas a huge amount of energy is needed for fusion reactions. 

Energy densities of fusion reactions are much higher than that of fission reactions.

Radioactive Material:

More radioactive material is formed in the process of nuclear fusion than in nuclear fission. 

Environmental Conditions:

For a nuclear fission process to occur, high-speed electrons are required, and the substance should have a critical mass. These reactions can take place at room temperature.

Whereas for the process of nuclear fusion, high temperature and high density are the necessary conditions for fusion to occur. Fusion reactions require a temperature up to 10⁷ Kelvin. 

For the fission reaction to occur, at least one external thermal neutron is needed, whereas no such external neutrons are needed for the fusion reactions.

Occurrence:

Fusion reactions occur naturally, such as in heavenly bodies like stars and the sun, whereas fission reactions do not occur naturally.

By-Products:

Fission reactions give off nuclear waste as a by-product, whereas fusion reactions do not have any such by-products.

Chain Reactions:

Nuclear fission reactions lead to chain reactions which can be hazardous sometimes due to the meltdowns, whereas nuclear fusion reactions do not lead to any chain reactions.

Examples:

The atomic bomb follows nuclear fission reactions. Nuclear power plants also make use of fission reactions. Uranium and platinum also follow fission reactions and are used in nuclear reactors because of their ease of initiation and control. 

The hydrogen bomb follows nuclear fusion reactions. Hydrogen isotopes are used for experimentation in fusion power plants. Fusion reactions are still an area of research of technology for producing electricity.

Which is better: Nuclear Fusion or Nuclear Fission?

Nuclear fusion is a safer and more efficient process. This is because nuclear fusion does not follow any chain reaction and hence does not lead to any hazardous meltdowns which happen in fission reactions. 

Fusion reactions are environment safe since they do not produce radioactive waste if performed with practice. However, they are very short-lived. Fusion reactions are also better because they release more energy, are inexhaustible, and have an availability worldwide as compared to fission reactions. No harmful environmental agents like the greenhouse gas, soot or acid rain are produced in the fusion reactions, and hence, human health will not be put in danger. 

Conclusion:

Fusion and fission are the processes by which atoms and molecules are formed. Fission is a process where two atoms separate, gaining a third. Fission is a complete disintegration of a particle into two or more particles. Fusion is a process where a single atom is reunited with two or more atoms. The most common type of fusion takes place when two neutrons or protons form a nucleus. A fusion can occur in a collision between two particles. For decades, scientists have been using the technologies of nuclear fusion to create electricity.