[140] Plutonium-237 | Pu | CID 105138 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more. Plutonium pyrophoricity can cause it to look like a glowing ember under certain conditions. The complete excretion of ingested plutonium by zooplankton makes their defecation an extremely important mechanism in the scavenging of plutonium from surface waters. a weapon pit) and inadequate heat removal the resulting self-heating may be significant. Plutonium forms intermediate compounds and alloys with most metals. 23: 177–233. Electron shell data. [73], The first production reactor that made plutonium-239 was the X-10 Graphite Reactor. Plutonium is much more common on Earth since 1945 as a product of neutron capture and beta decay, where some of the neutrons released by the fission process convert uranium-238 nuclei into plutonium-239. It is this energy that makes plutonium-239 useful in nuclear weapons and reactors. The latter are generally more useful, because the chemistries of thorium and plutonium are rather similar (both are predominantly tetravalent) and hence an excess of thorium would not be strong evidence that some of it was formed as a plutonium daughter. All of the remaining radioactive isotopes have half-lives that are less than 7,000 years. Plutonium isotopes are expensive and inconvenient to separate, so particular isotopes are usually manufactured in specialized reactors. [5], The presence of the isotope plutonium-240 in a sample limits its nuclear bomb potential, as plutonium-240 has a relatively high spontaneous fission rate (~440 fissions per second per gram—over 1,000 neutrons per second per gram),[16] raising the background neutron levels and thus increasing the risk of predetonation. Over 30 years later, each source is still producing about 300 watts which allows limited operation of each spacecraft. Fission of a kilogram of plutonium-239 can produce an explosion equivalent to 21,000 tons of TNT (88,000 GJ). [21] Egon Bretscher working on the British Tube Alloys project predicted this reaction theoretically in 1940. [103], The isotope plutonium-239 is a key fissile component in nuclear weapons, due to its ease of fission and availability. It is also used to make an atomic bomb. Pu2O3 spontaneously heats up and transforms into PuO2, which is stable in dry air, but reacts with water vapor when heated. A decade after barium was discovered, a Cambridge University professor suggested it be renamed to "plutonium" because the element was not (as suggested by the, As one article puts it, referring to information Seaborg gave in a talk: "The obvious choice for the symbol would have been Pl, but facetiously, Seaborg suggested Pu, like the words a child would exclaim, 'Pee-yoo!' In addition to consumption, fish can also be exposed to plutonium by their geographical distribution around the globe. [130] The skeleton, where plutonium accumulates, and the liver, where it collects and becomes concentrated, are at risk. [7] Resistivity then begins to increase with time at around 20 K due to radiation damage, with the rate dictated by the isotopic composition of the sample. [65] He chose the letters "Pu" as a joke, in reference to the interjection "P U" to indicate an especially disgusting smell, which passed without notice into the periodic table. [91][note 8] Each year about 20 tonnes of the element is still produced as a by-product of the nuclear power industry. The H-Canyon facility will be used to dissolve Pu metal for subsequent purification and conversion to plutonium dioxide (PuO{sub 2}) using Phase II of HB-Line. [132] When inhaled, plutonium can pass into the bloodstream. Polonium element and its compounds are highly radioactive. [7], Because of self-irradiation, a sample of plutonium fatigues throughout its crystal structure, meaning the ordered arrangement of its atoms becomes disrupted by radiation with time. Even in small amounts can cause significant self-heating. Required fields are marked *, Request OTP on [70], According to Kate Brown, the plutonium production plants at Hanford and Mayak in Russia, over a period of four decades, "both released more than 200 million curies of radioactive isotopes into the surrounding environment — twice the amount expelled in the Chernobyl disaster in each instance". Undeveloped eggs have a higher risk than developed adult fish exposed to the element in these waste areas. Plutonium is a radioactive element which was produced in 1940. [48][49] Finally, exceedingly small amounts of plutonium-238, attributed to the extremely rare double beta decay of uranium-238, have been found in natural uranium samples. [115], The "hot particle" theory in which a particle of plutonium dust irradiates a localized spot of lung tissue is not supported by mainstream research—such particles are more mobile than originally thought and toxicity is not measurably increased due to particulate form. Plutonium has an Atomic weight 239. The three primary research and production sites of the project were the plutonium production facility at what is now the Hanford Site, the uranium enrichment facilities at Oak Ridge, Tennessee, and the weapons research and design laboratory, now known as Los Alamos National Laboratory. [142] Similar studies found large accumulations of plutonium in the respiratory and digestive organs of cod, flounder and herring.[140]. [60][61][62] [67], The chemistry of plutonium was found to resemble uranium after a few months of initial study. The primary decay modes of isotopes with mass numbers lower than the most stable isotope, plutonium-244, are spontaneous fission and alpha emission, mostly forming uranium (92 protons) and neptunium (93 protons) isotopes as decay products (neglecting the wide range of daughter nuclei created by fission processes). A dedicated reactor operating on very low burnup (hence minimal exposure of newly formed plutonium-239 to additional neutrons which causes it to be transformed to heavier isotopes of plutonium) is generally required to produce material suitable for use in efficient nuclear weapons. The nonfissile uranium-238 can be converted to fissile plutonium-239 by the following nuclear reactions:. It is an actinide metal with a silvery-gray appearance but when oxidized it forms a dull coating. [156] Such plutonium transportation is without problems, according to a senior advisor (seniorrådgiver) at Statens strålevern. [93], Radioactive contamination at the Rocky Flats Plant primarily resulted from two major plutonium fires in 1957 and 1969. [8], Plutonium is a radioactive actinide metal whose isotope, plutonium-239, is one of the three primary fissile isotopes (uranium-233 and uranium-235 are the other two); plutonium-241 is also highly fissile. [57] The sample was actually a mixture of barium, krypton, and other elements, but this was not known at the time. [13] The ε phase, the highest temperature solid allotrope, exhibits anomalously high atomic self-diffusion compared to other elements. Plutonium is named after planet Pluto similar to its predecessor neptunium named after the planet Neptune. It reacts with hydrogen and nitrogen. Nicknamed Queen Marys by the workers who built them, the separation buildings were awesome canyon-like structures 800 feet long, 65 feet wide, and 80 feet high containing forty process pools. Much lower concentrations of radioactive isotopes were released throughout the operational life of the plant from 1952 to 1992. Properties: Plutonium has a specific gravity of 19.84 (a modification) at 25°C, melting point of 641°C, boiling point of 3232°C, with a valence of 3, 4, 5, or 6. [7] This trend continues down to 100 K, below which resistivity rapidly decreases for fresh samples. [94] As noted by Carl Johnson in Ambio, "Exposures of a large population in the Denver area to plutonium and other radionuclides in the exhaust plumes from the plant date back to 1953. It will react with carbon to form PuC, nitrogen to form PuN and silicon to form PuSi2. Plutonium-239 is virtually nonexistent in nature. [14], Pure plutonium-239 may have a multiplication factor (keff) larger than one, which means that if the metal is present in sufficient quantity and with an appropriate geometry (e.g., a sphere of sufficient size), it can form a critical mass. [34] Alpha particles generated by inhaled plutonium have been found to cause lung cancer in a cohort of European nuclear workers. Breakdown of plutonium in a spent nuclear fuel rod: plutonium-239 (~58%), 240 (24%), 241 (11%), 242 (5%), and 238 (2%). Plutonium isn’t of much use in any application due to its radioactive nature. The Fat Man bombs used in the Trinity nuclear test in July 1945, and in the bombing of Nagasaki in August 1945, had plutonium cores. [128], During the decay of plutonium, three types of radiation are released—alpha, beta, and gamma. The resulting investigation was undertaken by the president's Advisory Committee on Human Radiation Experiments, and it uncovered much of the material about plutonium research on humans. The presence of plutonium-240 limits a plutonium sample's usability for weapons or its quality as reactor fuel, and the percentage of plutonium-240 determines its grade (weapons-grade, fuel-grade, or reactor-grade). The δ phase plutonium–gallium and plutonium–aluminium alloys are produced by adding plutonium(III) fluoride to molten gallium or aluminium, which has the advantage of avoiding dealing directly with the highly reactive plutonium metal. Due to intense radioactivity, this metal glows blue in the dark. It is therefore used in radioisotope thermoelectric generators and radioisotope heater units such as those in the Cassini,[118] Voyager, Galileo and New Horizons[119] space probes, and the Curiosity [120] and Perseverance (Mars 2020) Mars rovers. [156], This article is about the radioactive element. This makes plutonium very sensitive to changes in temperature, pressure, or chemistry, and allows for dramatic volume changes following phase transitions from one allotropic form to another. Plutonium atoms have 94 electrons and the shell structure is 2.8.18.32.24.8.2. Plutonium, like most metals, has a bright silvery appearance at first, much like nickel, but it oxidizes very quickly to a dull gray, although yellow and olive green are also reported. Superintendent of Documents US Government Printing Office. [86][109] Hypothetically, as little as 4 kg of plutonium—and maybe even less—could be used to make a single atomic bomb using very sophisticated assembly designs. [72], During World War II the U.S. government established the Manhattan Project, which was tasked with developing an atomic bomb. These studies began in 1944 at the University of California at Berkeley's Radiation Laboratory and were conducted by Joseph G. Hamilton. 94. First, neptunium-238 (half-life 2.1 days) was synthesized, which subsequently beta-decayed to form the new element with atomic number 94 and atomic weight 238 (half-life 88 years). The Plutonium Files chronicles the lives of the subjects of the secret program by naming each person involved and discussing the ethical and medical research conducted in secret by the scientists and doctors. 5f6. Since uranium had been named after the planet Uranus and neptunium after the planet Neptune, element 94 was named after Pluto, which at the time was considered to be a planet as well. With an implosion weapon, plutonium is compressed to a high density with explosive lenses—a technically more daunting task than the simple gun-type design, but necessary to use plutonium for weapons purposes. Even though alpha radiation cannot penetrate the skin, ingested or inhaled plutonium does irradiate internal organs. [dubious – discuss][11], Criticality accidents have occurred in the past, some of them with lethal consequences. The primary decay mode for isotopes with mass numbers higher than plutonium-244 is beta emission, mostly forming americium (95 protons) isotopes as decay products. [note 9] These logs are planned to be encased in stainless steel and stored as much as 4 km (2 mi) underground in bore holes that will be back-filled with concrete. [99] In their final report the Commission put forth recommendations for developing a comprehensive strategy to pursue, including:[100], During and after the end of World War II, scientists working on the Manhattan Project and other nuclear weapons research projects conducted studies of the effects of plutonium on laboratory animals and human subjects. [5], Twenty radioactive isotopes of plutonium have been characterized. Plutonium, symbol Pu, has a Simple Monoclinic structure and Silver color. [note 10] The presence of up to 1% gallium per mass in weapons-grade plutonium alloy has the potential to interfere with long-term operation of a light water reactor. The danger increases with the amount of exposure. [56] Fermi called the element hesperium and mentioned it in his Nobel Lecture in 1938. [135] Ingestion or inhalation of large amounts may cause acute radiation poisoning and possibly death. Early research on plutonium was carried out secretly at the University of Chicago’s Metallurgical Laboratory. This can result in an explosion large enough to destroy a city if enough of the isotope is concentrated to form a critical mass. This page was last edited on 7 March 2021, at 23:35. Plutonium is the second transuranic element with an atomic number of 94 and part of the actinide group of the periodic table. This forms less than 1 per cent of natural uranium, and is extremely expensive to separate from it. The committee issued a controversial 1995 report which said that "wrongs were committed" but it did not condemn those who perpetrated them. It is an actinide metal with a silvery-gray appearance but when oxidized it forms a dull coating. If the alloying metal is sufficiently reductive, plutonium can be added in the form of oxides or halides. Nuclear Properties of Plutonium Plutonium belongs to the class of elements called transuranic elements whose atomic number is higher than 92, the atomic number of uranium. The American Society of Mechanical Engineers (ASME) established B Reactor as a National Historic Mechanical Engineering Landmark in September 1976. [110] In September 2000, the United States and the Russian Federation signed a Plutonium Management and Disposition Agreement by which each agreed to dispose of 34 tonnes of weapons-grade plutonium. Transuranium elements like Neptunium, Americium, Curium along with Plutonium are a radiological hazard and must be handled carefully with precaution. Plutonium isotopes undergo radioactive decay, which produces decay heat. Plutonium is named after planet Pluto similar to its predecessor neptunium named after the planet Neptune. The element is used in nuclear weapons as it is a key fissile component and because of its easier availability and ease of fission. Beta radiation can penetrate human skin, but cannot go all the way through the body. In: Challenges in Plutonium Science", "Kate Brown: Nuclear "Plutopias" the Largest Welfare Program in American History", "BBC NEWS – Science & Environment – US nuclear relic found in bottle", "8.1.1 The Design of Gadget, Fat Man, and "Joe 1" (RDS-1)", "The Yields of the Hiroshima and Nagasaki Explosions", "Proliferation of Nuclear Weapons and Materials to State and Non-State Actors: What It Means for the Future of Nuclear Power", "Historic American Engineering Record: B Reactor (105-B Building)", Stockholm International Peace Research Institute 2007, "Nuclear waste won't be going to Nevada's Yucca Mountain, Obama official says", "Disposal Subcommittee Report to the Full Commission", "The Human Plutonium Injection Experiments", "Injected! These neutrons can hit other atoms of plutonium-239 and so on in an exponentially fast chain reaction. [34], There are two aspects to the harmful effects of plutonium: the radioactivity and the heavy metal poison effects. Once in the bloodstream, plutonium moves throughout the body and into the bones, liver, or other body organs. [103], From 1945 to 1947, eighteen human test subjects were injected with plutonium without informed consent. It has machining characteristics similar to cast iron but changes to the plastic and malleable β (beta) form at slightly higher temperatures. Hamilton was looking to answer questions about how plutonium would vary in the body depending on exposure mode (oral ingestion, inhalation, absorption through skin), retention rates, and how plutonium would be fixed in tissues and distributed among the various organs. [34] Any uranium or plutonium isotopes produced during those three years are left and the rod goes back into production. [136], A commonly cited quote by Ralph Nader states that a pound of plutonium dust spread into the atmosphere would be enough to kill 8 billion people. Heat produced by the deceleration of these alpha particles makes it warm to the touch. The tests were used to create diagnostic tools to determine the uptake of plutonium in the body in order to develop safety standards for working with plutonium. [114], Plutonium recovered from spent reactor fuel poses little proliferation hazard, because of excessive contamination with non-fissile plutonium-240 and plutonium-242. [102] Most of the subjects, Eileen Welsome says, were poor, powerless, and sick. [8], Plutonium normally has six allotropes and forms a seventh (zeta, ζ) at high temperature within a limited pressure range. Plutonium has been called "the most complex metal" and "a physicist's dream but an engineer's nightmare" for its peculiar physical and chemical properties. [5][6], Resistivity is a measure of how strongly a material opposes the flow of electric current. In this equation, uranium-238, through the absorption of a neutron (n) and the emission of a quantum of energy known as a gamma ray (γ), becomes the isotope uranium-239 (the higher mass number reflecting the presence of one more neutron in the nucleus). Cohen estimated that one pound of plutonium could kill no more than 2 million people by inhalation, so that the toxicity of plutonium is roughly equivalent with that of nerve gas. Enriched uranium, by contrast, can be used with either method. [102], In the case of human subjects, this involved injecting solutions containing (typically) five micrograms of plutonium into hospital patients thought to be either terminally ill, or to have a life expectancy of less than ten years either due to age or chronic disease condition. It has six allotropic forms, which vary widely in crystal structure and density. [35][note 11], The usual transportation of plutonium is through the more stable plutonium oxide in a sealed package. [53] The former presence of 244Pu in the early Solar System has been confirmed, since it manifests itself today as an excess of its daughters, either 232Th (from the alpha decay pathway) or xenon isotopes (from its spontaneous fission). [2] If the metal is exposed long enough to a limited amount of water vapor, a powdery surface coating of PuO2 is formed. [71], The nuclear properties of plutonium-239 were also studied; researchers found that when it is hit by a neutron it breaks apart (fissions) by releasing more neutrons and energy. average. It has the physical appearance of metallic silver. [34], Plutonium is a reactive metal. Gamma radiation can go all the way through the body. The element normally exhibits six allotropes and four oxidation states. While it was still by no means clear that enough plutonium could be produced for use in bombs by the war's end, Hanford was by early 1945 in operation. Actinium is a radioactive element with an atomic number 89 of the periodic table. Ed. Care must be taken to avoid the accumulation of amounts of plutonium which approach critical mass, particularly because plutonium's critical mass is only a third of that of uranium-235. Careless handling of tungsten carbide bricks around a 6.2 kg plutonium sphere resulted in a fatal dose of radiation at Los Alamos on August 21, 1945, when scientist Harry Daghlian received a dose estimated to be 5.1 sievert (510 rems) and died 25 days later. Los Alamos received its first plutonium from Hanford on February 2. Both the T Plant and its sister facility in 200-West, the U Plant, were completed by October. [18] The isotope plutonium-238 is not fissile but can undergo nuclear fission easily with fast neutrons as well as alpha decay. [131] Plutonium passes only slowly through cell membranes and intestinal boundaries, so absorption by ingestion and incorporation into bone structure proceeds very slowly. [77], The entire plutonium weapon design effort at Los Alamos was soon changed to the more complicated implosion device, code-named "Fat Man". [107], The government covered up most of these radiation mishaps until 1993, when President Bill Clinton ordered a change of policy and federal agencies then made available relevant records. The interior had an eerie quality as operators behind seven feet of concrete shielding manipulated remote control equipment by looking through television monitors and periscopes from an upper gallery. Basic Chemical Properties of Plutonium. The α form has a low-symmetry monoclinic structure, hence its brittleness, strength, compressibility, and poor thermal conductivity. Neptunium is the only element that can stabilize the α phase at higher temperatures. Book review: The Plutonium Files: America's Secret Medical Experiments in the Cold War", "Plutonium Storage at the Department of Energy's Savannah River Site: First Annual Report to Congress", "Thermochemical Behavior of Gallium in Weapons-Material-Derived Mixed-Oxide Light Water Reactor (LWR) Fuel", "Science for the Critical Masses: How Plutonium Changes with Time", "From heat sources to heart sources: Los Alamos made material for plutonium-powered pumper", "Why the Cassini Mission Cannot Use Solar Arrays", "The Radioactive Heart of the New Horizons Spacecraft to Pluto", "NASA's Plutonium Problem Could End Deep-Space Exploration", "Nuclear pacemaker still energized after 34 years", SEALAB III – Diver's Isotopic Swimsuit-Heater System, Agency for Toxic Substances and Disease Registry, Centers for Disease Control and Prevention, "Risk of lung cancer mortality in nuclear workers from internal exposure to alpha particle-emitting radionuclides", "Radiological control technical training", "Lung cancer and internal lung doses among plutonium workers at the Rocky Flats Plant: a case-control study", "Radiation Protection, Plutonium: What does plutonium do once it gets into the body? Available plutonium properties... Essentials. [34] Plutonium absorbed by the body is excreted very slowly, with a biological half-life of 200 years. Plutonium. [2] Also formed is plutonium hydride but an excess of water vapor forms only PuO2. For other uses, see, This was not the first time somebody suggested that an element be named "plutonium". (1995). It is high even at low temperatures. [101] Animal studies found that a few milligrams of plutonium per kilogram of tissue is a lethal dose. It was named after the planet Pluto, having been discovered directly after Neptunium. [15] During fission, a fraction of the nuclear binding energy, which holds a nucleus together, is released as a large amount of electromagnetic and kinetic energy (much of the latter being quickly converted to thermal energy). Put your understanding of this concept to test by answering a few MCQs.