94 neptunium ← plutonium → americium Sm ↑ Pu ↓ (Uqq) periodic table
General
Name, Symbol, Number	plutonium, Pu, 94
Chemical series	actinides
Group, Period, Block	?, 7, f
Appearance	silvery white
Atomic mass	(244) g/mol
Electron configuration	[Rn] 5f6 7s2
Electrons per shell	2, 8, 18, 32, 24, 8, 2
Physical properties
Phase	solid
Density (near r.t.)	19.816 g/cm³
Liquid density at m.p.	16.63 g/cm³
Melting point	912.5 K (639.4 °C, 1182.9 °F)
Boiling point	3501 K (3228 °C, 5842 °F)
Heat of fusion	2.82 kJ/mol
Heat of vaporization	333.5 kJ/mol
Heat capacity	(25 °C) 35.5 J/(mol·K)
Vapor pressure P/Pa 1 10 100 1 k 10 k 100 k at T/K 1756 1953 2198 2511 2926 3499
Atomic properties
Crystal structure	monoclinic
Oxidation states	6, 5, 4, 3 (amphoteric oxide)
Electronegativity	1.28 (Pauling scale)
Ionization energies	1st: 584.7 kJ/mol
Atomic radius	175 pm
Miscellaneous
Magnetic ordering	no data
Electrical resistivity	(0 °C) 1.460 µΩ·m
Thermal conductivity	(300 K) 6.74 W/(m·K)
Thermal expansion	(25 °C) 46.7 µm/(m·K)
Speed of sound (thin rod)	(20 °C) 2260 m/s
Young's modulus	96 GPa
Shear modulus	43 GPa
Poisson ratio	0.21
CAS registry number	7440-07-5
Notable isotopes
Main article: Isotopes of plutonium iso NA half-life DM DE (MeV) DP 238Pu syn 88 y SF - - α 5.5 234U 239Pu trace 24.1 E3 y SF - - α 5.245 235U 240Pu syn 6.5 E3 y SF - - β 0.005 240Am 242Pu syn 373 E3 y SF - - α 4.984 238U 244Pu syn 80.8 E6 y α 4.666 240U SF - -
References

Plutonium is a radioactive, metallic, chemical element. It has the symbol Pu and the atomic number 94. Its atomic weight is 244.06, its density 19,816 kg/m³. It is the element used in most modern nuclear weapons. The most important, albeit not most stable, isotope of plutonium is ²³⁹Pu, with a half-life of 24,110 years. General Name, Symbol, Number Neptunium, Np, 93 Chemical series Actinides Period, Block 7, f Density, Hardness 20250 kg/m3, n/a Appearance Silvery metallic Atomic properties Atomic weight [237] u Atomic radius (calc. ... General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block 7, f Appearance silvery white Atomic properties Atomic weight [243] amu Atomic radius (calc. ... General Name, Symbol, Number Samarium, Sm, 62 Chemical series Lanthanides Group, Period, Block _ , 6 , f Density, Hardness 7353 kg/m3, no data Appearance silvery white Atomic properties Atomic weight 150. ... Image File history File links Download high resolution version (890x260, 0 KB)stub for unified link coding, copy of File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... State at standard temperature and pressure those numbered in red are gases those numbered in green are liquids those numbered in black are solid Natural occurrence those without borders have not been discovered/synthesized yet those with dotted borders do not occur naturally (Synthetic elements) those with dashed borders naturally... This is a list of the chemical elements, sorted by name. ... Categories: Chemical elements ... A chemical series is a group of chemical elements whose physical and chemical characteristics vary progressively from one end of the series to another. ... The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers 89 - 102 inclusive. ... 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The atomic mass of an element (also known as the relative atomic mass or average atomic mass or atomic weight) is the the average atomic mass of all the chemical elements isotopes as found in a particular environment, weighted by isotopic abundance. ... To help compare different orders of magnitude we list here masses between 60. ... Electron atomic and molecular orbitals In atomic physics, the electron configuration is the arrangement of electrons in an atom, molecule or other body. ... General Name, Symbol, Number radon, Rn, 86 Chemical series noble gases Group, Period, Block 18, 6, p Appearance colorless Atomic mass (222) g/mol Electron configuration [Xe] 4f14 5d10 6s2 6p6 Electrons per shell 2, 8, 18, 32, 18, 8 Physical properties Phase gas Melting point 202 K (-71 °C... Properties The electron is a subatomic particle. ... In physics and quantum chemistry, an energy level is a quantized energy of a bound quantum mechanical state. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... A solid is a state of matter, characterized by a definite volume and a definite shape (i. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... Room temperature, in laboratory reports, is taken to be roughly 21–23 degrees Celsius (70–73 degrees Fahrenheit), or 294–296 kelvins. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... The melting point of a solid is the temperature at which it changes state from solid to liquid. ... The melting point of a solid is the temperature at which it changes state from solid to liquid. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... The degree Celsius (°C or ℃ (Unicode 0x2103)) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701–1744), who first proposed a similar system in 1742. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... The boiling point of a substance is the temperature at which it can change state from a liquid to a gas throughout the bulk of the liquid. ... The kelvin (symbol: K) is the SI unit of temperature, and is one of the seven SI base units. ... The degree Celsius (°C or ℃ (Unicode 0x2103)) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701–1744), who first proposed a similar system in 1742. ... Fahrenheit is a temperature scale named after the German physicist Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ... Heat of fusion is the thermal energy which must be withdrawn to freeze a certain mass or quantity of liquid or added to melt a certain mass or quantity of solid. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... The heat of vaporization is a physical property of substances. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... Heat capacity (abbreviated Cth or just C, also called thermal capacity) is the ability of matter to store heat. ... The vapor pressure is the pressure (if the vapor is mixed with other gases, the partial pressure) of a vapor. ... Rose des Sables (Sand Rose), formed of gypsum crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... The oxidation state or oxidation number is defined as the sum of negative and positive charges in an atom, which indirectly indicates the number of electrons it has accepted or donated. ... In chemistry, an amphoteric substance is one that can react with either an acid or base (more generally, the word describes something made of, or acting like, two components). ... Electronegativity is the measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... Electronegativity is a measure of the attraction that an atom has for the bonding pair of electrons in a covalent bond. ... The ionization energy (IE) of an atom is the energy required to strip it of an electron. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... The poopie is the distance from the atomic nucleus to the outmost stable electron orbital in a atom that is at equilibrium. ... To help compare different orders of magnitude this page lists lengths between 100 pm and 1 nm (10-10 m and 10-9 m). ... Picometre (American spelling: picometer) is an SI measure of length that is equal to 10−12 of a metre. ... In physics, magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials. ... // Headline text POOP!! Danny Hornsby (also known as Gnome) is a measure indicating how strongly a Gnome can opposes the flow of electric current. ... It is the quantity of heat, Q, transmitted through a unit thickness, L, in a direction normal to a surface of unit area, A, due to a unit temperature gradient, ΔT, under steady state conditions and when the heat transfer is dependent only on the temperature gradient. ... In physics, thermal conductivity, λ, is the quantity of heat transmitted, due to unit temperature gradient, in unit time under steady conditions in a direction normal to a surface of unit area, when the heat transfer is dependent only on the temperature gradient thermal conductivity = heat flow rate / (distance × temperature... The coefficient of thermal expansion is used in two ways: as a volumetric thermal expansion coefficient as a linear thermal expansion coefficient These characteristics are closely related. ... The speed of sound c (from Latin celeritas, velocity) varies depending on the medium through which the sound waves pass. ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ... In solid mechanics, Youngs modulus (also known as the modulus of elasticity or elastic modulus) is a measure of the stiffness of a given material. ... In materials science, shear modulus S, sometimes referred to as the modulus of rigidity, is defined as the ratio of shear stress to the shear strain: S = shear stress/shear strain = (F/A)/Φ. Another commonly accepted symbol is G. Shear modulus is usually measured in ksi (kips per square... When a sample of material is stretched in one direction, it tends to get thinner in the other two directions. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Isotopes are forms of a chemical element whose nuclei have the same atomic number, Z, but different atomic masses, A. The word isotope, meaning at the same place, comes from the fact that all isotopes of an element are located at the same place on the periodic table. ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... 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. ... In physics, the decay mode describes a particular way a particle decays. ... The decay energy is the energy released by a nuclear decay. ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... A Synthetic radioisotope is a radioisotope Radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 109 seconds (a gigasecond) and 1010 seconds (32 years and 320 years). ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle and transforms into a nucleus with mass number 4 less and atomic number 2 less. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery gray metallic Atomic mass 238. ... A radionuclide is an atom with an unstable nucleus. ... To help compare orders of magnitude of different times this page lists times between 32 000 years and 320 000 years (1012 seconds—a terasecond—and 1013 seconds). ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle and transforms into a nucleus with mass number 4 less and atomic number 2 less. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery gray metallic Atomic mass 238. ... A Synthetic radioisotope is a radioisotope Radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 32 000 years and 320 000 years (1012 seconds—a terasecond—and 1013 seconds). ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... 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. ... General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block 7, f Appearance silvery white Atomic properties Atomic weight [243] amu Atomic radius (calc. ... A Synthetic radioisotope is a radioisotope Radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 320 000 years and 3 200 000 years (1013 seconds and 1014 seconds) See also times of other orders of magnitude. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery gray metallic Atomic mass 238. ... A Synthetic radioisotope is a radioisotope Radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... To help compare orders of magnitude of different times this page lists times between 1015 seconds (a petasecond) and 1016 seconds (32 million years and 320 million years) See also times of other orders of magnitude. ... Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle and transforms into a nucleus with mass number 4 less and atomic number 2 less. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery gray metallic Atomic mass 238. ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms ions (cations) and has metallic bonds, and metals are sometimes described as a lattice of positive ions (cations) in a cloud of electrons. ... A chemical element, often called simply element, is the class of atoms which contain the same number of protons. ... 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Notable characteristics

Plutonium is silvery in pure form, but has a yellow tarnish when oxidized. Peculiarly, the metal goes through phases of contraction as its temperature is increased. The most fundamental reactions in chemistry are the redox processes. ...

Image showing colors of various oxidation states of Pu in solution on the left and colors of only one Pu oxidation state (IV) on the right in solutions containing different anions.

The heat given off by alpha particle emission makes plutonium warm to the touch in reasonable quantities; larger amounts can boil water. It displays four ionic oxidation states in aqueous solution: Download high resolution version (1240x511, 65 KB)Various colors of plutonium in solution. ... Download high resolution version (1240x511, 65 KB)Various colors of plutonium in solution. ... Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle and transforms into a nucleus with mass number 4 less and atomic number 2 less. ... The oxidation state or oxidation number is defined as the sum of negative and positive charges in an atom, which indirectly indicates the number of electrons it has accepted or donated. ...

• Pu³⁺ (blue lavender)
• Pu⁴⁺ (yellow brown)
• PuO²⁺ (pink orange)
• PuO⁺ (thought to be pink; this ion is unstable in solution and will disproportionate into Pu⁴⁺ and PuO²⁺; the Pu⁴⁺ will then oxidize the remaining PuO⁺ to PuO²⁺, being reduced in turn to Pu³⁺. Thus, aqueous solutions of plutonium tend over time towards a mixture of Pu³⁺ and PuO²⁺.)

Applications

The isotope Plutonium-239 is a key fissile component in modern nuclear weapons, due to its ease of fissioning and availability. The critical mass for an unreflected sphere of plutonium is 16 kg, but through the use of a neutron reflecting tamper the pit of plutonium in a fission bomb is reduced to 10 kg, which is a sphere with a diameter of 10 cm. Complete detonation of plutonium will produce an explosion of 20 kilotons per kilogram. (See also Nuclear Weapon Design.) This article or section should include material from Fissile material In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the epicenter. ... San Francisco Critical Mass, 29th April, 2005. ... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... The first nuclear weapons, though large, cumbersome and inefficient, provided the basic design building blocks of all future weapons. ...

Plutonium could also be used to manufacture radiological weapons or as a (not particularly deadly) poison. A radiological weapon (or radiological dispersion device, RDD) is any weapon that is designed to spread radioactive contamination, either to kill, or to deny the use of an area (a modern version of salting the earth) and consists of a device (such as a nuclear or conventional explosive) which spreads... The skull and crossbones symbol traditionally used to label a poisonous substance. ...

The plutonium isotope ²³⁸Pu is an alpha emitter with a half-life of 87 years. These characteristics make it well suited for electrical power generation for devices which must function without direct maintenance for timescales approximating a human lifetime. It is therefore used in RTGs such as those powering the Galileo and Cassini space probes; earlier versions of the same technology powered seismic experiments on the Apollo Moon missions. A radioisotope thermoelectric generator (RTG) is a simple electrical generator which obtains its power from radioactive decay. ... Galileo being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. ... This is an artists concept of Cassini during the Saturn Orbit Insertion (SOI) maneuver, just after the main engine has begun firing. ... Seismology (from the Greek seismos = earthquake and logos = word) is the scientific study of earthquakes and the movement of waves through the Earth. ... Description Role: Earth and Lunar Orbit Crew: 3; CDR, CM pilot, LM pilot Dimensions Height: 36. ... Crust composition Oxygen 43% Silicon 21% Aluminium 10% Calcium 9% Iron 9% Magnesium 5% Titanium 2% Nickel 0. ...

²³⁸Pu has been used successfully to power artificial heart pacemakers, to reduce the risk of repeated surgery. It has been largely replaced by lithium-based batteries recharged by induction, but as of 2003 there were somewhere between 50 and 100 plutonium-powered pacemakers still implanted and functioning in living patients. This article is about a medical device which electrically stimulates the heart. ...

History

Plutonium was discovered in 1941 by Dr. Glenn T. Seaborg, Edwin M. McMillan, J. W. Kennedy, and A. C. Wahl by deuteron bombardment of uranium in the 60-inch cyclotron of the Berkeley Radiation Laboratory at the University of California, Berkeley, but the discovery was kept secret. It was named after the planet Pluto, having been discovered directly after neptunium (which itself was one higher on the periodic table than uranium), by analogy with the ordering of the planets in the solar system. During the Manhattan Project, large reactors were set up in Hanford, Washington for the production of plutonium, which was used in two of the first atomic bombs (the first was tested at Trinity site, the second dropped on Nagasaki, Japan). 1941 was a common year starting on Wednesday (link will take you to calendar). ... Glenn T. Seaborg Glenn Theodore Seaborg (April 19, 1912 – February 25, 1999) was an American chemist, who was prominent in the discovery and isolation of many transuranic elements (including plutonium, during the Manhattan Project), for which he won the Nobel Prize in Chemistry in 1951. ... Edwin Mattison McMillan (September 18, 1907-September 7, 1991) was the first scientist to produce a transuranium element. ... Deuterium (symbol 2H) is a stable isotope of hydrogen with a natural abundance of one atom in 6500 of hydrogen. ... The Berkeley Lab is perched on a hill overlooking the Berkeley central campus and San Francisco Bay. ... University of California, Berkeley The University of California, Berkeley (also known as Cal, University of California, UC Berkeley, UCB, or simply Berkeley) is a public coeducational university situated in the foothills of Berkeley, California, USA to the east of San Francisco Bay, overlooking the Golden Gate. ... Atmospheric characteristics Atmospheric pressure 0. ... General Name, Symbol, Number Neptunium, Np, 93 Chemical series Actinides Period, Block 7, f Density, Hardness 20250 kg/m3, n/a Appearance Silvery metallic Atomic properties Atomic weight [237] u Atomic radius (calc. ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery gray metallic Atomic mass 238. ... Control panels and operators for calutrons at the Y-12 Plant in Oak Ridge, Tennessee. ... Nuclear power station at Leibstadt, Switzerland. ... Hanford Site during the Manhattan Project. ... An early stage in the Trinity fireball. ... Megane-bashi (Spectacles Bridge) Nagasaki   listen? (長崎市; -shi, literally long peninsula) is the capital and the largest city of Nagasaki Prefecture located at the south-western coast of Kyushu, Japan. ...

Large stockpiles of plutonium were built up by both the old Soviet Union and the United States during the Cold War—it was estimated that 300,000 kg of plutonium had been accumulated by 1982. Since the end of the Cold War, these stockpiles have become a focus of nuclear proliferation concerns. In 2002, the United States Department of Energy took possession of 34 metric tons of excess weapons grade plutonium stockpiles from the United States Department of Defense, and as of early 2003 was considering converting several nuclear power plants in the US from enriched uranium fuel to MOX fuel as a means of disposing of these. This map shows two essential global spheres during the Cold War up until 1959. ... 1982 is a common year starting on Friday of the Gregorian calendar. ... Nuclear proliferation is the spread from nation to nation of nuclear technology, including nuclear power plants but especially nuclear weapons. ... The United States Department of Energy (DOE) is a Cabinet-level department of the United States government responsible for energy policy and nuclear safety. ... The United States Department of Defense, abbreviated as DoD or DOD and sometimes called the Defense Department, is a civilian Cabinet organization of the United States government. ... Enriched uranium is uranium whose uranium-235 content has been increased through the process of isotope separation. ... Mixed Oxide, or MOX fuel, is an alternate to lightly enriched uranium fuel in the light water reactors which predominate nuclear power generation. ...

During the initial years after the discovery of plutonium, when its biological and physical properties were very poorly understood, a series of human radiation experiments were performed by the U.S. government and by private organizations acting on its behalf. From the time of April 1945 to July 1947, 18 men, women, and children were deliberately injected with solutions containing various concentrations of plutonium by doctors working with the Manhattan Project. Though the injections were only to occur in what were percieved by the doctors as terminally ill patients at the hospital, in at least one instance this was not the case and the injections, in all cases, were conducted without any kind of informed consent from the subjects of the experiment. The episode is considered today, to be a gross violation of human rights and of the Hippocratic Oath, and is widely regarded as one of the darkest chapters in 20th-century American medical history. [1] Since the discovery of ionizing radiation, a number of human radiation experiments have been performed to understand the effects of ionizing radiation and radioactive contamination on the human body. ... Control panels and operators for calutrons at the Y-12 Plant in Oak Ridge, Tennessee. ... The Hippocratic Oath is an oath traditionally taken by physicians, in which certain ethical guidelines are laid out. ... The 20th century lasted from 1901 to 2000 in the Gregorian calendar. ...

Occurrence

While almost all plutonium is manufactured synthetically, extremely tiny trace amounts are found naturally in uranium ores. These come about by a process of neutron capture by ²³⁸U nuclei, initially forming ²³⁹U; two subsequent beta decays then form ²³⁹Pu (with a ²³⁹Np intermediary), which has a half-life of 24,100 years. This is also the process used to manufacture ²³⁹Pu in nuclear reactors. Some traces of ²⁴⁴Pu remain from the birth of the solar system from waste of supernovae, because its half-life (80 million yrs) is so long. General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block ?, 7, f Appearance silvery gray metallic Atomic mass 238. ... See r-process or 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. ... General Name, Symbol, Number Neptunium, Np, 93 Chemical series Actinides Period, Block 7, f Density, Hardness 20250 kg/m3, n/a Appearance Silvery metallic Atomic properties Atomic weight [237] u Atomic radius (calc. ... Nuclear power station at Leibstadt, Switzerland. ...

A relatively high concentration of plutonium was discovered at the natural fission reactor in Oklo, Gabon in 1972. Since 1945, about 10 tons of plutonium have been released onto Earth through nuclear explosions. Oklo is a place in the West African state of Gabon. ... 1972 was a leap year that started on a Saturday. ... 1945 was a common year starting on Monday (link will take you to calendar). ... Earth - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... A nuclear explosion (nuclear detonation) has occurred: twice using a nuclear weapon during war (during World War II, the atomic bombings of Hiroshima and Nagasaki) many times testing a nuclear weapon a series of tests of nuclear explosives for construction purposes; see Operation Plowshare Potential other applications (not yet applied...

Manufacture

The isotope Pu-239 is the key ingredient to most nuclear weapons. Its manufacture is therefore important to nuclear weapon states. Controlling or preventing the manufacture of refined Pu-239 is also important in preventing nuclear proliferation. Nuclear proliferation is the spread from nation to nation of nuclear technology, including nuclear power plants but especially nuclear weapons. ...

Pu-239 is normally manufactured in nuclear reactors. If U-238 is exposed to neutron radiation, the nuclei will occasionally capture a neutron, becoming U-239. This happens more easily with fast neutrons than with slow neutrons, although both can be used. The U-239 rapidly undergoes beta decay to give Np-239, which rapidly undergoes a second beta decay, giving Pu-239. Fission activity is relatively rare, so even after significant exposure, the Pu-239 is still mixed with a great deal of U-238 (and possibly other isotopes of uranium, oxygen, other components of the original material, and fission products). The Pu-239 can then be chemically separated from the rest of the material to give high-purity Pu-239 metal. Neutron radiation consists of free neutrons. ... 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. ... A thermal neutron is a free neutron with a kinetic energy level of ca. ... 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. ...

If Pu-239 captures a neutron, it becomes Pu-240. Pu-240 undergoes spontaneous fission at a relatively high rate. As a result, plutonium containing a significant fraction of Pu-240 is not well-suited to use in nuclear weapons; it emits neutron radiation, making handling more difficult, and its presence can lead to a "fizzle" in which a small explosion occurs, destroying the weapon but not causing fission of a significant fraction of the fuel. (The US has constructed a single experimental bomb using only reactor-grade plutonium [2].) Moreover, Pu-239 and Pu-240 cannot be chemically distinguished, so expensive and difficult isotope separation would be necessary to build a nuclear weapon using such a mix. Thus for the purposes of plutonium production, it is necessary to remove the U-238 frequently, before significant amounts of Pu-239 can be converted into Pu-240. Isotope separation is the process of concentrating specific isotopes of a chemical element by removing other isotopes. ...

A nuclear reactor that is used to produce plutonium must therefore have a means for exposing U-238 to neutron radiation, and for frequently rotating this U-238. A reactor running on unenriched or moderately enriched uranium naturally contains a great deal of U-238. However, most commercial power reactor designs require the entire reactor to shut down, often for weeks, in order to change the fuel elements. They therefore produce plutonium in a mix of isotopes that is not well-suited to weapon construction. Such a reactor could have machinery added that would permit U-238 slugs to be placed near the core and changed frequently, or it could be shut down frequently, so proliferation is a concern; for this reason, the IAEA inspects licensed reactors frequently. A few commercial power reactor designs, RBMK and CANDU, do permit refueling without shutdowns, and they therefore pose a proliferation risk. (In fact, the RBMK was built by the Soviet Union during the cold war, so despite their ostensibly peaceful purpose, it is likely that plutonium production was a design criterion. Their requirement for refueling made a proper containment structure infeasible, drastically worsening the Chernobyl accident.) IAEA The International Atomic Energy Agency (IAEA), established as an autonomous organization on July 29, 1957, seeks to promote the peaceful use of nuclear energy and to inhibit its use for military purposes. ... RBMK is an acronym for the Russian reaktor bolshoi moshchnosty kanalny which means reactor (of) large power (with) channels, and describes a now-obsolete class of nuclear power reactor which was built only in the Soviet Union. ... The CANDU reactor is a pressurized-heavy water, natural-uranium power reactor designed in the 1960s by a partnership between Atomic Energy of Canada Limited and the Hydro-Electric Power Commission of Ontario as well as several private industry participants. ... RBMK is an acronym for the Russian reaktor bolshoi moshchnosty kanalny which means reactor (of) large power (with) channels, and describes a now-obsolete class of nuclear power reactor which was built only in the Soviet Union. ... The nuclear power plant at Chernobyl. ...

Most plutonium is produced in research reactors or plutonium production reactors. Some production reactors are called breeder reactors because they produce more plutonium than they consume fuel; in principle, such reactors make extremely efficient use of natural uranium. In practice, their construction and operation is sufficiently difficult, and proliferation is a serious enough concern, that they are generally only used to produce plutonium. Plutonium reactors are generally (but not always) fast reactors, since fast neutrons are somewhat more efficient at plutonium production. The fast breeder or fast breeder reactor (FBR) is a type of fast neutron reactor that produces more fissile material than it consumes. ... 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. ...

Compounds

Plutonium reacts readily with oxygen, forming PuO and PuO₂, as well as intermediate oxides. It reacts with the halides, giving rise to compounds such as PuX₃ where X can be F, Cl, Br or I; PuF₄ is also seen. The following oxyhalides are observed: PuOCl, PuOBr and PuOI. It will react with carbon to form PuC, nitrogen to form PuN and silicon to form PuSi₂. This article is about the chemical element oxygen. ... A halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Atomic mass 12. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance dark gray, bluish tinge Atomic mass 28. ...

Allotropes

A diagram of the allotropes of plutonium at ambient pressure

Even at ambient pressure, plutonium occurs in a variety of allotropes. These allotropes differ widely in crystal structure and density; the α and δ allotropes differ in density by more than 25% at the same volume. Phase diagram for plutonium at ambient pressure. ... Allotropy (Gr. ...

The presence of these many allotropes makes machining plutonium very difficult, as it changes state very readily. The reasons for the complicated phase diagram are not entirely understood; recent research has focused on constructing accurate computer models of the phase transitions.

Isotopes

Twenty-one plutonium radioisotopes have been characterized. The most stable are Pu-244, with a half-life of 80.8 million years, Pu-242, with a half-life of 373,300 years, and Pu-239, with a half-life of 24,110 years. All of the remaining radioactive isotopes have half-lives that are less than 7,000 years. This element also has eight meta states, though none are very stable (all have half-lives less than one second). A radionuclide is an atom with an unstable nucleus. ... 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. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... A nuclear isomer is a metastable state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ...

The isotopes of plutonium range in atomic weight from 228.0387 u (Pu-228) to 247.074 u (Pu-247). The primary decay modes before the most stable isotope, Pu-244, are spontaneous fission and alpha emission; the primary mode after is beta emission. The primary decay products before Pu-244 are uranium and neptunium isotopes (neglecting the wide range of daughter nuclei created by fission processes), and the primary products after are americium isotopes. ... The unified atomic mass unit (u), or dalton (Da), is a small unit of mass used to express atomic masses and molecular masses. ... In physics, the decay mode describes a particular way a particle decays. ... Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle and transforms into a nucleus with mass number 4 less and atomic number 2 less. ... 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. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... General Name, Symbol, Number americium, Am, 95 Chemical series actinides Group, Period, Block 7, f Appearance silvery white Atomic properties Atomic weight [243] amu Atomic radius (calc. ...

Key isotopes for applications are Pu-239, which is suitable for use in nuclear weapons and nuclear reactors, and Pu-238, which is suitable for use in radioisotope thermoelectric generators; see above for more details. The isotope Pu-240 undergoes spontaneous fission very readily, and is produced when Pu-239 is exposed to neutrons. The presence of Pu-240 in a material limits its nuclear bomb potential since it emits neutrons randomly, increasing the difficulty of initiating accurately the chain reaction at the good instant and thus reducing the bomb's reliability and power. Plutonium consisting of more than about 90% Pu-239 is called weapon-grade plutonium; plutonium obtained from commercial reactors generally contains at least 20% Pu-240 and is called reactor-grade plutonium. A chain reaction is a sequence of reactions where a reactive product or biproduct causes more additional reactions. ...

Precautions

All isotopes and compounds of plutonium are toxic and radioactive. While plutonium is sometimes described in media reports as "the most toxic substance known to man", there is general agreement among experts in the field that this is incorrect. As of 2003, there has yet to be a single human death officially attributed to plutonium exposure. Naturally-occurring radium is about 200 times more radiotoxic than plutonium, and some organic toxins like Botulin toxin are still more toxic. Botulin toxin, in particular, has a lethal dose of 300pg/kg, far less than the quantity of plutonium that poses a significant cancer risk. In addition, beta and gamma emitters (including the C-14 and K-40 in nearly all food) can cause cancer on casual contact, which alpha emitters cannot. A toxin, in a scientific context, is a biologically produced substance that causes injury to the health of a living thing on contact or absorption, typically by interacting with biological macromolecules such as enzymes and receptors. ... General Name, Symbol, Number Radium, Ra, 88 Series Alkali earth metals Group, Period, Block 2(IIA), 7, s Density, Hardness 5000 kg/m3, no data Appearance Silvery white metallic Atomic Properties Atomic weight (226. ... Botulin toxin or botox is the toxic compound produced by the bacterium Clostridium botulinum. ...

Orally, plutonium is less toxic (non-oncogenically speaking) than several common substances, including caffeine, acetaminophen, some vitamins, pseudoephedrine, and any number of plants and fungi. It is perhaps somewhat more toxic than pure ethanol, but less so than tobacco and many illegal drugs (some such as marijuana are negligibly toxic). From a purely chemical standpoint, its toxicity is probably on par with lead and other heavy metals. An oncogenic process which is any tumor-forming process. ... Caffeine molecular structure Caffeine, also known as trimethylxanthine, coffeine, theine, mateine, guaranine, methyltheobromine and 1,3,7-trimethylxanthine, is a xanthine alkaloid found naturally in such foods as coffee beans, tea, kola nuts, Yerba mate, guarana berries, and (in small amounts) cacao beans. ... Acetaminophen (USAN) or paracetamol (INN), is a popular analgesic and antipyretic drug that is used for the relief of fever, headaches, and other minor aches and pains. ... Vitamins are organic chemicals that a given living organism requires in trace quantities for good health, but which the organism cannot synthesize, and therefore must obtain from its diet. ... Pseudoephedrine is a sympathomimetic amine commonly used as a decongestant. ... Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Hepatophyta - liverworts Anthocerophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a fern... Divisions Chytridiomycota Zygomycota Glomeromycota Ascomycota Basidiomycota Yellow fungus For the fictional character, see Fungus the Bogeyman. ... Ethyl alcohol, also known as ethanol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ... Species N. glauca N. longiflora N. rustica N. sylvestris N. tabacum Ref: ITIS 30562 as of 2002-08-28 Tobacco () is a broad-leafed plant of the nightshade family, indigenous to North and South America, whose dried and cured leaves are often smoked (see tobacco smoking) in the form of... Cannabis is a plant also known as Cannabis sativa, hemp, or marijuana. ... General Name, Symbol, Number lead, Pb, 82 Chemical series poor metals Group, Period, Block 14, 6, p Appearance bluish white Atomic mass 207. ... For other meanings, see heavy metal The term heavy metal may have various more general or more specific meanings. ...

That said, there is no doubt that plutonium may be extremely dangerous when handled incorrectly. The alpha radiation it emits does not penetrate the skin, but can irradiate internal organs when plutonium is inhaled or ingested. Particularly at risk are the skeleton, onto the surface of which it is likely to be absorbed, and the liver, where it will collect and become concentrated. Extremely fine particles of plutonium (on the order of micrograms) can cause lung cancer if inhaled into the lungs. An alpha particle is deflected by a magnetic field Alpha particles or alpha rays are a form of particle radiation which are highly ionizing and have low penetration. ... In biology, the skeleton or skeletal system is the biological system providing support in living organisms. ... The liver is an organ in vertebrates, including humans. ... The incidence of lung cancer is highly correlated with smoking. ... The heart with relation to the lungs (from an older edition of Grays Anatomy) This x-ray of the human chest shows the lungs as dark regions The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ...

Other substances including ricin, botulinum toxin and tetanus toxin are fatal in doses of (sometimes far) under one milligram, and others (the nerve agents, nutmeg by injection, the amanita toxin, the fugu toxin) are in the range of a few milligrams. As such, plutonium is not unusual in terms of toxicity, even by inhalation. In addition, those substances are fatal in hours to days, whereas plutonium (and other cancer-causing radioactives) give an increased chance of illness decades in the future. Considerably larger amounts may cause acute radiation poisoning and death if ingested or inhaled; however, so far, no human is known to have immediately died because of inhaling or ingesting plutonium and many people have measurable amounts of plutonium in their bodies. Castor beans The protein ricin (pronounced rye-sin) is a poison manufactured from the castor bean (Ricinus communis). ... Botulin toxin or botox is the toxic compound produced by the bacterium Clostridium botulinum. ... Tetanus is a serious and often fatal disease caused by the exotoxin tetanospasmin which is produced by the Gram-positive, anaerobic bacterium Clostridium tetani. ... Species About 100 species, including: Myristica argentea Myristica fragrans Myristica malabarica The nutmegs Myristica are a genus of evergreen trees indigenous to tropical southeast Asia and Australasia. ... There are about 900 to 1000 species of fungus (mostly mushroom) in the Amanita genus (family Amanitaceae, order Agaricales), which contains some of the most toxic known mushrooms. ... Genera (See list at end of article) Takifugu is a genus of pufferfish, often better known with the Japanese name Fugu (Japanese: 河豚 or 鰒). ... Radiation poisoning, also called radiation sickness, is a form of damage to organic tissue due to excessive exposure to ionizing radiation. ...

The chemical and radiological toxicity of plutonium should be distinguished from each other and also from the potential danger of a runaway fission reaction or "criticality". Many in the anti-nuclear movement and in the continuing green politics movement refer to plutonium as the most dangerous substance known to man because of its use in nuclear power plants, which they perceive to be inherently dangerous, and for its potential as a catalyst for nuclear weapons proliferation. CND logo In British politics, the Campaign for Nuclear Disarmament has been at the forefront of the peace movement in the United Kingdom and claims to be Europes largest single-issue peace campaign. ... Green politics is a body of political ideas informed by environmentalism aimed at developing a sustainable society. ...

It is possibly confusion between these two issues that has led to sensational exaggerations of plutonium toxicity. A 1989 paper by Bernard L. Cohen states: Sensationalism is a manner of being extremely controversial, loud, attention-grabbing, or otherwise sensationalistic. ...

Pu hazards are far better understood than [those from insecticides or food additives], and the one fatality per 300 years they may someday cause is truly trivial by comparison. In spite of the facts we have cited here, facts well known in the scientific community, the myth of Pu toxicity lingers on. (MS Word) (html)

It must be noted, however, that in contrast to naturally occurring radioisotopes such as radium or C-14, plutonium was manufactured, concentrated, and isolated in large amounts (hundreds of metric tons) during the Cold War for weapons production. These piles, whether in weapons form or otherwise, could pose a significant toxicologic risk, largely because, unlike chemical or biological agents, there is no practical way to destroy them.

Toxicity issues aside, care must be taken to avoid the accumulation of amounts of plutonium which approach critical mass, the amount of plutonium which will self-generate a nuclear reaction. Despite not being confined by external pressure as is required for a nuclear weapon, it will nevertheless heat itself and break whatever confining environment it is in. Shape is relevant; compact shapes such as spheres are to be avoided. Plutonium in solution is more likely to form a critical mass than the solid form. A weapon-scale nuclear explosion cannot occur accidentally, since it requires a greatly supercritical mass in order to explode rather than simply melt or fragment. However, a marginally critical mass will cause a lethal dose of radiation and has in fact done so in the past on several occasions. San Francisco Critical Mass, 29th April, 2005. ...

Multiple criticality accidents have occurred in the past at least in the US and the former USSR, some of them with lethal consequences. Careless handling of a 6.2 kg plutonium sphere resulted in a lethal dose of radiation at Los Alamos on August 21, 1945, when scientist Harry Daghlian received a dose estimated to be 510 rems (5.1 Sv) and died four weeks later. Nine months later, another Los Alamos scientist, Louis Slotin, died from a similar accident. In 1958, during a process of purifying plutonium at Los Alamos, a critical mass was formed in a mixing vessel, which resulted in the death of a crane operator. Other accidents of this sort have occurred in the Soviet Union, Japan, and many other countries. (See List of nuclear accidents) A criticality accident (also sometimes referred to as an excursion or power excursion) occurs when a nuclear chain reaction is accidentally allowed to occur in fissile material, such as enriched uranium or plutonium. ... August 21 is the 233rd day of the year (234th in leap years) in the Gregorian Calendar. ... 1945 was a common year starting on Monday (link will take you to calendar). ... Harry K. Daghlian, Jr. ... The Röntgen equivalent man or rem (symbol rem) is an obsolete unit of radiation dose. ... The sievert (symbol Sv) is an SI derived unit of equivalent dose or effective dose (of radiation), and so is dependent upon the biological effects of radiation as opposed to the physical aspects, characterised by the absorbed dose (measured in grays). ... A sketch used by doctors to determine the amount of radiation to which each person in the room had been exposed during the excursion. ... 1958 was a common year starting on Wednesday of the Gregorian calendar. ... Pathways from airborne radioactive contamination to man This is a list of notable accidents involving nuclear material. ...

Metallic plutonium is also a fire hazard, especially if the material is finely divided. It reacts chemically with oxygen and water which may result in an accumulation of plutonium hydride, a pyrophoric substance; that is, a material that will ignite in air at room temperature. Plutonium expands considerably in size as it oxidizes and thus may break its container. The radioactivity of the burning material is an additional hazard. Magnesium oxide sand is the most effective material for extinguishing a plutonium fire. It cools the burning material, acting as a heat sink, and also blocks off oxygen. Water is also effective. There was a major plutonium-initiated fire at the Rocky Flats Plant near Boulder, Colorado in 1969 [3]. To avoid these problems, special precautions are necessary to store or handle plutonium in any form; generally a dry inert atmosphere is required [4]. A pyrophoric substance is a substance that ignites spontaneously, that is, its autoignition temperature is below room temperature. ... A large copper heatsink. ... Rocky Flats Plant was a weapons production facility of the Atomic Energy Commission about 15 miles northwest of Denver, Colorado on a windy plateau called Rocky Flats. ... Pearl Street Mall in Downtown Boulder Boulder (40n01, 105w16 MST) is a city located in Boulder County, Colorado, USA. As of the 2000 census, the city had a total population of 94,673. ... 1969 was a common year starting on Wednesday (the link is to a full 1969 calendar). ... Inert is the state of doing little or nothing. ... Atmosphere may refer to: a celestial body atmosphere, e. ...

References

• Los Alamos National Laboratory - Plutonium
• It's Elemental - Plutonium
• WebElements.com - Plutonium
• EnvironmentalChemistry.com - Plutonium (JavaScript required, browser-restricted access)
• Federation of American Scientists - Plutonium production
• nuclearweaponarchive.org - Plutonium Manufacture and Fabrication
• Ambient pressure phase diagram of plutonium - A unified theory for α-Pu and δ-Pu, P. Söderlind, Europhys. Lett., 55 (4), p. 525 (2001).

External links

• The Dangers of Plutonium - Anti-nuclear viewpoint
• collection of articles on plutonium at the Canadian Coalition for Nuclear Responsibility
• The Myth of Plutonium Toxicity
• Criticality Accidents Report Issued
• Nuclear Accidents Timeline
• Nuclear Weapons: Disposal Options for Surplus Weapons-Usable Plutonium
• Unraveling the Phase Diagram of Plutonium
• Physical, Nuclear, and Chemical, Properties of Plutonium from IEER