Nuclear transmutation is the conversion of one chemical element or isotope into another, which occurs through nuclear reactions. Natural transmutation occurs when radioactive elements spontaneously decay over a long period of time and transform into other more stable elements. Artificial transmutation occurs 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 as well as conventional fission power reactors. Nuclear transmutation is considered as a possible mechanism for reducing the volume and hazard of radioactive waste. The periodic table of the chemical elements A chemical element, or element, is a type of atom that is distinguished by its atomic number; that is, by the number of protons in its nucleus. ... For other uses, see Isotope (disambiguation). ... In nuclear physics, a nuclear reaction is a process in which two nuclei or nuclear particles collide to produce products different from the initial particles. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... A chemical element, often called simply element, is a substance that cannot be divided or changed into different substances by ordinary chemical methods. ... Atom Smasher redirects here. ... This article is about the fusion reactor device. ... Radioactive wastes are waste types containing radioactive chemical elements that do not have a practical purpose. ...

History

The term transmutation dates back to the search for the philosopher's stone. In alchemy, it was believed that the transformation of base metals into gold could be accomplished in table-top experiments. The alchemical belief in transmutation was based on a thoroughly wrong understanding of the underlying processes. The realisation that such simple transformations would not be possible began when Lavoisier first identified the chemical elements and Dalton restored the Greek notion of atoms to explain chemical processes. The disintegration of atoms is a distinct process involving much greater energies than could be achieved by alchemists. For other uses, see Philosophers stone (disambiguation). ... For other uses, see Alchemy (disambiguation). ... Lavoisier redirects here. ... John Dalton John Dalton (September 6, 1766 – July 27, 1844) was an English chemist and physicist, born at Eaglesfield, near Cockermouth in Cumberland. ... Properties For alternative meanings see atom (disambiguation). ...

It was first consciously applied to modern physics by Frederick Soddy when he, along with Ernest Rutherford, discovered that radioactive thorium was converting itself into radium in 1901. At the moment of realization, Soddy later recalled, he shouted out: "Rutherford, this is transmutation!" Rutherford snapped back, "For Christ's sake, Soddy, don't call it transmutation. They'll have our heads off as alchemists."^{[citation needed]} Frederick Soddy in 1922. ... Ernest Rutherford, 1st Baron Rutherford of Nelson OM PC FRS (30 August 1871 – 19 October 1937), widely referred to as Lord Rutherford, was a chemist (B.Sc. ... General Name, Symbol, Number thorium, Th, 90 Chemical series Actinides Group, Period, Block n/a, 7, f Appearance silvery white Standard atomic weight 232. ... For other uses, see Radium (disambiguation). ... Year 1901 (MCMI) was a common year starting on Tuesday (link will display calendar) of the Gregorian calendar (or a common year starting on Monday [1] of the 13-day-slower Julian calendar). ...

Later in the twentieth century the transmutation of elements within stars was elaborated, accounting for the relative abundance of elements in the universe. In their 1957 paper Synthesis of the Elements in Stars,^[1] William Alfred Fowler, Margaret Burbidge, Geoffrey Burbidge, and Fred Hoyle explained how the abundances of essentially all but the lightest chemical elements could be explained by the process of nucleosynthesis in stars. For the British astronomer, see Alfred Fowler. ... Margaret Burbidge (nee Eleanor Margaret Peachey) (born August 12, 1919) is a British astrophysicist, noted for original research and holding many administrative posts, including director of the Royal Greenwich Observatory. ... Geoffrey Ronald Burbidge (born September 24, 1925) is a British-American physics professor in the University of California, San Diego. ... Sir Frederick Hoyle, FRS, (born on June 24, 1915 in Gilstead, Yorkshire, England – August 20, 2001 in Bournemouth, England)[1] was a British astronomer, he was educated at Bingley Grammar School and notable for a number of his theories that run counter to current astronomical opinion, and a writer of... Nucleosynthesis is the process of creating new atomic nuclei from preexisting nucleons (protons and neutrons). ...

Author Ken Croswell summarised their discoveries thus: Ken Croswell is an astronomer and author living in Berkeley, California. ...

Burbidge, Burbidge, Fowler, Hoyle
Took the stars and made them toil:
Carbon, copper, gold, and lead
Formed in stars, is what they said^[2]

Ironically, it transpired that, under true nuclear transmutation, it is far easier to turn gold into lead than the reverse reaction, which was the one the alchemists had ardently pursued. Nuclear experiments have successfully transmuted lead into gold, but the expense far exceeds any gain.^[3] It would be easier to convert gold into lead via neutron capture and beta decay by leaving gold in a nuclear reactor for a long period of time. The process of neutron capture can proceed in two ways - as a rapid process (an r-process) or a slow process (an s-process). ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ...

¹⁹⁷Au + n → ¹⁹⁸Au (halflife 2.7 days) → ¹⁹⁸Hg + n → ¹⁹⁹Hg + n → ²⁰⁰Hg + n → ²⁰¹Hg + n → ²⁰²Hg + n → ²⁰³Hg (halflife 47 days) → ²⁰³Tl + n → ²⁰⁴Tl (halflife 3.8 years) → ²⁰⁴Pb (halflife 1.4x10¹⁷ years) GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... The process of neutron capture can proceed in two ways - as a rapid process (an r-process) or a slow process (an s-process). ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... This article is about the element. ... General Name, Symbol, Number thallium, Tl, 81 Chemical series poor metals Group, Period, Block 13, 6, p Appearance silvery white Standard atomic weight 204. ... General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ...

Transmutation of nuclear wastes

Overview

Transmutation of transuranium elements (actinides) such as the isotopes of plutonium, neptunium, americium, and curium has the potential to help solve the problems posed by the management of radioactive waste, by reducing the proportion of long-lived isotopes it contains. When irradiated with fast neutrons in a nuclear reactor, these isotopes can be made to undergo nuclear fission, destroying the original actinide isotope and producing a spectrum of radioactive and nonradioactive fission products. In chemistry, transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92, the atomic number of Uranium. ... The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers 89 - 102 inclusive. ... For other uses, see Isotope (disambiguation). ... This article is about the radioactive element. ... General Name, Symbol, Number neptunium, Np, 93 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery metallic Standard atomic weight (237) g·mol−1 Electron configuration [Rn] 5f4 6d1 7s2 Electrons per shell 2, 8, 18, 32, 22, 9, 2 Physical properties Phase solid Density (near r. ... General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery white sometimes yellow Standard atomic weight (243) g·mol−1 Electron configuration [Rn] 5f7 7s2 Electrons per shell 2, 8, 18, 32, 25, 8, 2 Physical properties Phase solid Density (near... General Name, Symbol, Number curium, Cm, 96 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery Atomic mass (247) g/mol Electron configuration [Rn] 5f7 6d1 7s2 Electrons per shell 2, 8, 18, 32, 25, 9, 2 Physical properties Phase solid Density (near r. ... Radioactive wastes are waste types containing radioactive chemical elements that do not have a practical purpose. ... A fast neutron is a free neutron with a kinetic energy level close to 1 MeV (10 TJ/kg, hence a speed of 14,000 km/s. ... Core of a small nuclear reactor used for research. ... For the generation of electrical power by fission, see Nuclear power plant. ... The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series derives its name from the first element in the series, actinium. ... Fission products are the residues of fission processes. ...

Reactor types

For instance, plutonium can be reprocessed into MOX fuels and transmuted in standard reactors. The heavier elements could be transmuted in fast reactors, but probably more effectively in a subcritical reactor[1] which is sometimes known as an energy amplifier and which was devised by Carlo Rubbia. Fusion neutron sources have also been proposed as well suited.^[4][5] The Mox are a alien race that inhabit Planet X, they are divided into clans which seem to be forever at war. ... A fast neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons. ... A subcritical reactor is a nuclear fission reactor that produces fission without achieving criticality. ... In nuclear physics, an energy amplifier is a novel type of nuclear power reactor, a subcritical reactor, in which an energetic particle beam is used to stimulate a reaction, which in turn releases enough energy to power the particle accelerator and leave an energy profit for power generation. ... Carlo Rubbia (born March 31, 1934) is an Italian physicist. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing sustainable fusion power. ... A neutron source is a device, used in solid state physics (see neutron diffraction), particle physics and to start nuclear chain reactions, that emits neutrons. ...

Reasoning behind transmutation

Isotopes of plutonium and other actinides tend to be long-lived with half-lives of many thousands of years, whereas radioactive fission products tend to be shorter-lived (most with half-lives of 30 years or less). From a waste management viewpoint, transmutation of actinides eliminates a very long-term radioactive hazard and replaces it with a much shorter-term one. Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

It is important to understand that the threat posed by a radioisotope is influenced by many factors including the chemical and biological properties of the element. For instance caesium has a relatively short biological halflife (1 to 4 months) while strontium and radium both have very long biological half-lives. As a result strontium-90 and radium are much more able to cause harm than caesium-137 when a given activity is ingested. A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... For other uses, see Biology (disambiguation). ... General Name, Symbol, Number caesium, Cs, 55 Chemical series alkali metals Group, Period, Block 1, 6, s Appearance silvery gold Standard atomic weight 132. ... The biological half life of a substance is the time required for half of that substance to be removed from an organism by either a physcial or a chemical process. ... General Name, Symbol, Number strontium, Sr, 38 Chemical series alkaline earth metals Group, Period, Block 2, 5, s Appearance silvery white metallic Standard atomic weight 87. ... For other uses, see Radium (disambiguation). ... General Name, Symbol, Number Strontium, Sr, 38 Series Alkaline earth metal Group, Period, Block 2 (IIA), 5, s Density, Hardness 2630 kg/m3, 1. ... Caesium-137 is a radioactive isotope which is formed mainly by nuclear fission. ...

Many of the actinides are very radiotoxic because they have long biological half-lives and are alpha emitters. In transmutation the intention is to convert the actinides into fission products. The fission products are very radioactive, but the majority of the activity will decay away within a short time. The most worrying shortlived fission products are those that accumulate in the body, such as iodine-131 which accumulates in the thyroid gland, but it is hoped that by good design of the nuclear fuel and transmutation plant that such fission products can be isolated from man and his environment and allowed to decay. In the medium term the fission products of highest concern are strontium-90 and caesium-137; both have a half life of about 30 years. The caesium-137 is responsible for the majority of the external gamma dose experienced by workers in nuclear reprocessing plants and at this time (2005) to workers at the Chernobyl site. When these medium-lived isotopes have decayed the remaining isotopes will pose a much smaller threat. An alpha particle is deflected by a magnetic field Alpha radiation consists of helium-4 nuclei and is readily stopped by a sheet of paper. ... Fission products are the residues of fission processes. ... For other uses, see Iodine (disambiguation). ... Nuclear Fuel Process A graph comparing nucleon number against binding energy Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... This article is about electromagnetic radiation. ... // Nuclear reprocessing separates any usable elements (e. ... This article is about the city of Chernobyl. ...

Long-lived fission products

Some radioactive fission products can be converted into shorter-lived radioisotopes by transmutation. Transmutation of all fission products with halflife greater than one year is studied in [2], with varying results. Fission products are the atomic fragments left after a large nucleus fissions. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Annum is a Latin noun meaning year. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... The decay energy is the energy released by a nuclear decay. ... An electronvolt (symbol: eV) is the amount of kinetic energy gained by a single unbound electron when it passes through an electrostatic potential difference of one volt, in vacuum. ... In physics, the decay mode describes a particular way a particle decays. ... Krypton 85 (85Kr) is a radioisotope of krypton. ... General Name, Symbol, Number Strontium, Sr, 38 Series Alkaline earth metal Group, Period, Block 2 (IIA), 5, s Density, Hardness 2630 kg/m3, 1. ... Caesium-137 is a radioactive isotope which is formed mainly by nuclear fission. ... Fission products are the atomic fragments left after a large nucleus fissions. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... Annum is a Latin noun meaning year. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... The decay energy is the energy released by a nuclear decay. ... An electronvolt (symbol: eV) is the amount of kinetic energy gained by a single unbound electron when it passes through an electrostatic potential difference of one volt, in vacuum. ... In physics, the decay mode describes a particular way a particle decays. ... Iodine-129 (129I) is a radioisotope of iodine, which decays with a half-life of 16. ...

Sr-90 and Cs-137, with halflives of about 30 years, are the largest radiation emitters in used nuclear fuel on a scale of decades to a few hundreds of years, and are not easily transmuted because they have low neutron absorption cross sections. Instead, they should simply be stored until they decay. Given that this length of storage is necessary, the fission products with shorter halflives can also be stored until they decay. Strontium-90 (90Sr) is a radioactive isotope of strontium, with a half life of 28. ... Caesium-137 is a radioactive isotope which is formed mianly by nuclear fission (half life is about 27 years). ... Neutron absorption is the process in nuclear physics whereby a neutron is absorbed into the nucleus of an atom. ... Cross section may refer to the following In geometry, Cross section is the intersection of a 3-dimensional body with a plane. ...

The next longer-lived fission product is Sm-151, which has a halflife of 90 years, and is such a good neutron absorber that most of it is transmuted while the nuclear fuel is still being used; however effectively transmuting the remaining Sm-151 in nuclear waste would require separation from other isotopes of samarium. Given the smaller quantities and its low-energy radioactivity, Sm-151 is less dangerous than Sr-90 and Cs-137 and can also be left to decay. 151Sm is an radioisotope of samarium with a halflife of 90 years, decaying with low-energy beta emission, and a fission product yield of 0. ... General Name, Symbol, Number samarium, Sm, 62 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white Atomic mass 150. ...

Finally, there are 7 long-lived fission products. They have much longer halflives in the range 211,000 years to 16 million years. Two of them, Tc-99 and I-129, are mobile enough in the environment to be potential dangers, are free or mostly free of mixture with stable isotopes of the same element, and have neutron cross sections that are small but adequate to support transmutation. Also, Tc-99 can substitute for U-238 in supplying Doppler broadening for negative feedback for reactor stability. ^[6] Most studies of proposed transmutation schemes have assumed transuranics, ⁹⁹Tc, and ¹²⁹I as the targets for transmutation, with other fission products, activation products, and possibly reprocessed uranium remaining as waste. [3] General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Atomic mass (98) g/mol Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... Iodine-129 (129I) is a radioisotope of iodine, which decays with a half-life of 16. ... There are two objects with this name: Unterseeboot 238 Uranium-238, the most common isotope of uranium This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Doppler broadening is a broadening of spectral lines due to thermal agitation. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series transition metals Group, Period, Block 7, 5, d Appearance silvery gray metal Standard atomic weight [98](0) g·mol−1 Electron configuration [Kr] 4d5 5s2 Electrons per shell 2, 8, 18, 13, 2 Physical properties Phase solid Density (near r. ... Iodine-129 (129I) is a radioisotope of iodine, which decays with a half-life of 16. ... Activation products are materials made radioactive by neutron activation. ... Reprocessed uranium (RepU) is the uranium recovered from nuclear fuel reprocessing. ...

Of the remaining 5 long-lived fission products, Se-79, Sn-126 and Pd-107 are produced only in small quantities (at least in today's thermal neutron, U-235-burning light water reactors) and the last two should be relatively inert. The other two, Zr-93 and Cs-135, are produced in larger quantities, but also not highly mobile in the environment. They are also mixed with larger quantities of other isotopes of the same element. 79Se is a radioisotope of selenium present in spent nuclear fuel and the wastes resulting from reprocessing this fuel. ... Tin-126 is a radioisotope with a halflife of 230,000 years and is one of only 7 long-lived fission products. ... Palladium-107 is a fission product with a halflife of 6. ... This article does not cite its references or sources. ... Uranium-235 is an isotope of uranium that differs from the elements other common isotope, uranium-238, by its ability to cause a rapidly expanding fission chain reaction. ... A light water reactor or LWR is a thermal nuclear reactor that uses ordinary water, also called light water, as its neutron moderator. ... 93Zr is a radioisotope of zirconium with a half life of 1. ... Caesium-135 has a half-life of 2. ...

References

1. ^ William Alfred Fowler, Margaret Burbidge, Geoffrey Burbidge, and Fred Hoyle, 'Synthesis of the Elements in Stars', Reviews of Modern Physics, vol. 29, Issue 4, pp. 547–650
2. ^ Ken Croswell, The Alchemy of the Heavens
3. ^ Anne Marie Helmenstine, Turning Lead into Gold: Is Alchemy Real?, About.com:Chemistry, retrieved January 2008
4. ^ Rita Plukiene, Evolution Of Transuranium Isotopic Composition In Power Reactors And Innovative Nuclear Systems For Transmutation, PhD Thesis, Vytautas Magnus University, 2003, retrieved January 2008
5. ^ Takibayev A., Saito M., Artisyuk V., and Sagara H., 'Fusion-driven transmutation of selected long-lived fission products', Progress in nuclear energy, Vol. 47, 2005, retrieved January 2008.
6. ^ http://www.osti.gov/bridge/servlets/purl/10180577-PCAEyE/10180577.PDF Transmutation of Selected Fission Products in a Fast Reactor