Nuclear fission is a physical process that consists of dividing the nucleus of an atom considered unstable into two smaller nuclei, through the bombardment of particles such as neutrons.
This process is an exothermic chemical reaction and occurs when there is a large release of energy. It is considered a form of nuclear transmutation, as the fragments generated are not of the same element as the isotope that generated them.
The first studies on the nuclear fission process they were discovered in 1939 by Otto Hahn (1879-1968) and Fritz Strassmann (1902-1980).
This process originates when the heavy nucleus is hit by a neutron and after the collision, it releases an immense amount of energy.
During the collision, new neutrons are released that will collide with new nuclei, causing successive fissions of nuclei, thus establishing a reaction that is called Chain reaction, according to the scheme below:
The nuclear fission process is also important for nuclear power production. Nuclear reactors are able to control the violence of the fission process, slowing the action of neutrons so that an explosion does not occur. And in this way nuclear energy is generated, which is considered clean, efficient and does not emit gases.
Learn more about Nuclear energy.
An important factor in determining the nuclear fission process is the analysis of core stability. To carry it out, it is necessary to calculate the ratio between the number of protons and the number of neutrons.
The lack of neutrons can make the distance between protons too short, that repulsion becomes inevitable, causing the nucleus to fission. However, the nuclear force is short-range and the excess of neutrons can cause an unsustainable electromagnetic repulsion surface, which can also cause nuclear fission.
Nuclear Fission and Nuclear Fusion
Oftentimes, nuclear fission and fusion processes are carried out together, which can cause some confusion in their real objectives.
While nuclear fission consists of split an atom into two or more fragments, by means of neutron bombardment, releasing a large amount of energy, nuclear fusion is also able to release large amounts of energy, but through the process of union or collision of two atoms. This union is purposely done.
Examples of nuclear fission
The best known example of nuclear fission is the reaction that takes place with uranium. When a neutron with enough energy hits the uranium nucleus, it releases neutrons that can cause the fission of other nuclei, as shown in the image below:
This reaction is also known to release large amounts of energy.
However, nuclear fission is also used in other processes, such as radioactivity, which results from the fission process and is used in medicine to treat tumors and other diseases, for example.
See more about Radioactivity.
However, its greatest use is in the production of atomic bombs, which originate from the process of nuclear fusion and fission. They have a high destructive power.
