The reaction can be controlled or moderated by introducing a substance that absorbs neutrons before they can react with more uranium atoms. Whether or not a chain reaction can occur depends on the energy of the neutrons that are released and how close the neighbor uranium atoms are. These two neutrons can go on to split other uranium nuclei, resulting in a nuclear chain reaction. In this particular reaction, one uranium nucleus breaks into a barium nucleus, a krypton nucleus, and two neutrons. A common fission reaction produces barium-141 and krypton-92.

The energy from the neutrons can cause the uranium nucleus to break in any of a number of different ways. In nuclear power plants, energetic neutrons are directed into a sample of the isotope uranium-235. Other times, energy is added to a nucleus to overcome the nuclear binding energy holding the protons and neutrons together. Sometimes this is supplied naturally, from radioactive decay of an element. For example, the fission of one kilogram of uranium releases as much energy as burning around four billion kilograms of coal.Įnergy is required in order for fission to occur. The energy released by nuclear fission is considerable. However, the daughter nuclei may still be radioactive. The mass change and energy release yield smaller nuclei that are more stable than the original heavy nucleus. The nucleus oscillates, so the repulsion may overcome the short-range attraction, causing the atom to split. The reason fission occurs is that energy upsets the balance between the electrostatic repulsion between positively-charged protons and the strong nuclear force that holds protons and neutrons together. Nuclear fusion and nuclear fission are two different types of energy-releasing reactions in which energy is released from high-powered atomic bonds between the particles within the nucleus. Fission is a type of nuclear reaction that may occur spontaneously or as a result of a particle striking an atomic nucleus. The original heavy atom is termed the parent nucleus, and the lighter nuclei are daughter nuclei. Nuclear fusion is a reaction in which two or more atomic nuclei, usually deuterium and tritium (hydrogen variants), combine to form one or more different atomic nuclei and subatomic particles (neutrons or protons). Fission is the splitting of an atomic nucleus into two or more lighter nuclei accompanied by energy release.

Nuclear fission meaning