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However, the fusion of 92 235U can result in the high temperature needed for fusion. Only the interior of stars has the high temperature needed to initiate fusion.

It is also known as a thermonuclear reaction since a very high temperature (>10 6 K) is necessary to overcome the electrostatic attraction between the two nuclei that are undergoing fusion. The positively charged atomic nuclei oppose one another and prevent easy fusion as a result. are allowed to strike the nuclei of lighter elements, a reaction like this occurs. When highly accelerated protons, neutrons, etc. A tremendous amount of energy is released in this process. The nuclear reaction in which two or more lighter nuclei combine with each other to form a stable nucleus of higher stability is called a nuclear fusion reaction. Thus, two or more lighter nuclei have a tendency to combine or fuse together to give the nucleus of higher atomic mass and binding energy resulting in higher stability. The lighter nuclei have low binding energy and hence are less stable. This principle is used to make an atom bomb. A huge amount of energy is liberated in this process. These neutrons undergo further fission in an uncontrolled manner until the whole uranium (U-235) gets finished. In such a reaction, nuclear released from the reaction further strike nuclei to cause more fission with the release of more energy and more neutrons. When these pass through carbon and hit new 92 235U nuclei, they are once again slowed down, causing fission and neutrons. These slow down moving neutrons and collide with a nucleus and further fission takes place at a controlled rate.įor example: When the slow-moving neutrons collide with 92 235U nucleus, a fission reaction takes place and more neutrons are produced. In this reaction, the speed of neutrons is decreased by mixing fissionable material with moderators such as graphite or heavy water. Controlled Nuclear FissionĪ controlled nuclear reaction is carried out for the continuous production of energy. The neutrons released can further attack other uranium atoms causing fission, and hence nuclear fission reaction is a chain reaction. Nuclear fission is a type of reaction mechanism wherein heavier nuclei are divided into lighter nuclei and simultaneously release a significant quantity of energy when they are bombarded with high-energy particles.Įxample: When 92 235U is bombarded with slow-moving neutrons, it breaks up into two fragments 56 144Ba and 36 90Kr, and a number of neutrons.

However, these reactions are brought about by high-energy particles like slow neutrons. The heavier nuclei are unstable and frequently disintegrate to form nuclei with intermediate atomic weights because of the low binding energy per nucleon. A tremendous amount of energy is liberated in this process. Nuclear reaction in which a heavy nucleus ( 235U, Th, Ra) when interacting with a bombarding particle ( 1 0n) breaks up into two or more lighter nuclei of nearly equal size/mass is called nuclear fission reaction. Such nuclear reactions release a tremendous amount of energy. Nuclear fission involves the splitting of heavy nuclei into lighter nuclei, while nuclear fission is the process by which lighter nuclei combine to form a heavy stable nucleus. Nuclear fission and fusion are such types of nuclear reactions in which the composition of certain nuclei undergo change to form an atom of a new element.