Nuclear transmutation

Nuclear transmutation is the conversion of one chemical element or isotope into another. In other words, atoms of one element can be changed into atoms of another element by a process which occurs either through nuclear reactions (in which an outside particle reacts with a nucleus), or through radioactive decay (where no outside particle is needed). Transmutation technology has the potential to greatly reduce the long-term negative effects of radioactive wastes on human populations by reducing its radioactive half-life.Not all radioactive decay or nuclear reactions cause transmutation, but all transmutation is caused by either decay or nuclear reaction. The most common types of radioactive decay that do not cause transmutation are gamma decay and the related process internal conversion. However, most other types of decay do cause transmutation of the decaying radioisotope. Similarly, a few nuclear reactions do not cause transmutation (for example the gain or loss of a neutron might not cause transmutation), although in practice, most nuclear reactions, and types of nuclear are the creation of all the chemical elements we observe naturally. Most of this happened in the distant past, however (see section below on transmutation in the universe).One type of natural transmutation observable in the present occurs when certain radioactive elements present in nature spontaneously decay by a process that causes transmutation, such as alpha or beta decay. An example is the natural decay of potassium-40 to argon-40, which forms most of the argon in air. Also on Earth, natural transmutations from the different mechanism of natural nuclear reactions occur, due to cosmic ray bombardment of elements (for example, to form carbon-14), and also occasionally from natural neutron bombardment (for example, see natural nuclear fission reactor).Artificial transmutation may occur in machinery that has enough energy to cause changes in the nuclear structure of the elements. Machines that can cause artificial transmutation include particle accelerators and tokamak reactors. Conventional fission power reactors also cause artificial transmutation, not from the power of the machine, but by exposing elements to neutrons produced by a fission from an artificially produced nuclear chain reaction.Artificial nuclear transmutation has been considered as a possible mechanism for reducing the volume and hazard of radioactive waste.