In a nuclear reactor or nuclear weapon, most fission events are induced by bombardment with another particle such as a neutron. Most nuclear fuels undergo spontaneous fission only very slowly, decaying mainly via an alpha/ beta decay chain over periods of millennia to eons. These fuels break apart into a range of chemical elements with atomic masses near 100 (fission products). The most common nuclear fuels are 235U (the isotope of uranium with an atomic mass of 235) and 239Pu (the isotope of plutonium with an atomic mass of 239). Chemical isotopes that can sustain a fission chain reaction are called nuclear fuels, and are said to be fissile.
#Fission example chemistry free#
Nuclear fission differs from other forms of radioactive decay in that it can be harnessed and controlled via a chain reaction: free neutrons released by each fission event can trigger yet more events, which in turn release more neutrons and cause more fissions. Concerns over nuclear waste accumulation and over the immense destructive potential of nuclear weapons counterbalance the desirable qualities of fission as an energy source, and give rise to intense ongoing political debate over nuclear power. The amount of free energy contained in nuclear fuel is millions of times the amount of free energy contained in a similar mass of chemical fuel such as gasoline, making nuclear fission a very tempting source of energy however, the waste products of nuclear fission are highly radioactive and remain so for millennia, giving rise to a nuclear waste problem. Nuclear fuels can be part of a self-sustaining chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon.
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Fission is useful as a power source because some materials, called nuclear fuels, both generate neutrons as part of the fission process and also undergo triggered fission when impacted by a free neutron.
Nuclear fission produces energy for nuclear power and to drive explosion of nuclear weapons. Fission of heavy elements is an exothermic reaction and can release substantial amounts of useful energy both as gamma rays and as kinetic energy of the fragments ( heating the bulk material where fission takes place). The by-products include free neutrons, photons usually in the form gamma rays, and other nuclear fragments such as beta particles and alpha particles. Hence, fission is a form of elemental transmutation. Nuclear fission-also known as atomic fission-is a process in nuclear physics and nuclear chemistry in which the nucleus of an atom splits into two or more smaller nuclei as fission products, and usually some by-product particles. The particular elements and number of neutrons produced by each single fission event are random. A thermal (slow-moving) neutron is absorbed by the nucleus of a uranium-235 atom, which in turn splits into fast-moving lighter elements (fission products) and free neutrons.
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