Plutonium

{| border="1" cellpadding="2" cellspacing="0" align="right" style="margin-left:0.5em; margin-bottom:0.5em" | colspan="2" cellspacing="0" cellpadding="2" | {| align="center" border="0" | colspan="2" align="center" | neptunium – plutonium – americium |- | rowspan="3" valign="center" | Samarium
Pu

|- | align="center" |

Periodic table (standard)

|} |- ! colspan="2" align=center bgcolor="ff99cc"|General |- | List of elements by name, List of elements by symbol, List of elements by number | Plutonium, Pu, 94 |- | Chemical series | Actinides |- | periodic table period, periodic table block | period 7 element, f-block |- | Density, Mohs hardness scale | 19816 kilogram per cubic metre, no data |- | color | align="center" | silvery white metal
|- ! colspan="2" align="center" bgcolor="#ff99cc" | Atomic properties |- | Atomic weight | 1 E-25 kg |- | Atomic radius (calc.) | 1 E-10 m |- | Covalent radius | no data |- | van der Waals radius | no data |- | Electron configuration | [Radon]5f⁶7S-orbital² |- | electron's per energy level | 2,8,18,32,24,8,2 |- | Oxidation states (Oxide) | 6,5,4,3 (amphoteric) |- | Crystal structure | Monoclinic |- ! colspan="2" align="center" bgcolor="ff99cc"|Physical properties |- | State of matter | Solid (magnetism) |- | Melting point | 912.5 Kelvin (1182.9 Fahrenheit) |- | Boiling point | 3503 K (5846 �F) |- | Molar volume | 12.29 scientific notation10^-6 cubic metre per mole |- | Heat of vaporization | 344 kilojoule per mole |- | Heat of fusion | 2.84 kJ/mol |- | Vapor pressure | ND Pascal at 298 K |- | Velocity of sound | 2260 metre per second at 293.15 K |- ! colspan="2" align="center" bgcolor="ff99cc"|Miscellaneous |- | Electronegativity | 1.28 (Pauling scale) |- | Specific heat capacity | ND joule per kilogram-kelvin |- | Electrical conductivity | 0.666 10⁶/m ohm |- | Thermal conductivity | 6.74 watt per metre-kelvin |- | 1^st ionization potential | 584.7 kJ/mol |- ! colspan="2" align="center" bgcolor="ff99cc"|Most stable isotopes |- | colspan="2" | {| border="1" cellspacing="0" cellpadding="2" width="100%" ! Isotope ! natural abundance ! half-life ! decay mode ! decay energy megaelectron volt ! decay product |- | ²³⁸Pu | synthetic radioisotope | 1 E9 s | Spontaneous fission
alpha emission |
5.5 | ²³⁴Uranium |- | ²³⁹Pu | trace radioisotope | 1 E12 s | Spontaneous fission
alpha emission |
5.245 | ²³⁵Uranium |- | ²⁴⁰Pu | synthetic radioisotope | 1 E12 s | Spontaneous fission
beta emission |
0.005 | ²⁴⁰Americium |- | ²⁴²Pu | synthetic radioisotope | 1 E13 s | SF
α |
4.984 | ²³⁸Uranium |- | ²⁴⁴Pu | synthetic radioisotope | 1 E15 s | alpha emission
Spontaneous fission | 4.666
| ²⁴⁰Uranium |} |- ! colspan="2" align="center" bgcolor="#ff99cc" |International System of Units units & standard temperature and pressure are used except where noted. |} 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 kilogram per cubic metre. It is the element used in most modern nuclear weapons. The most important isotope of plutonium is ²³⁹Pu, with a half-life of 24,200 years. == Notable characteristics == Plutonium is silvery in pure form, but has a yellow tarnish when oxidation. Peculiarly, the metal goes through phases of contraction as its temperature is increased. The heat given off by alpha decay makes plutonium warm to the touch in reasonable quantities; larger amounts can boil water. It displays four ionic oxidation states in aqueous solution: *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#Enriched_materials.) Plutonium could also be used to manufacture radiological weapons or as a (not particularly deadly) poison. 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 radioisotope thermoelectric generators such as those powering the Galileo probe and Cassini probe space probes; earlier versions of the same technology powered seismology experiments on the Apollo program Moon missions. ²³⁸Pu has been used successfully to power artificial heart Artificial 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. == 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 (planet), 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 nuclear reactor were set up in Hanford Site 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, Nagasaki, 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. 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 United States medical history. [http://www.thebulletin.org/article.php?art_ofn=nd99longworth] == 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 ²³⁹Neptunium 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. 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. === 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. 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. 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.) 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. 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.) 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. == Compounds == Plutonium reacts readily with oxygen, forming PuO and Plutonium dioxide, 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. == Allotropes == 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. 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 24,100 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). The isotopes of plutonium range in atomic weight from 228.0387 atomic mass unit (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. 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. == Precautions == All isotopes and compounds of plutonium are toxic and radioactive. While plutonium is sometimes described in media reports as "the most Toxin 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. Orally, plutonium is less toxic (non-oncogenically speaking) than several common substances, including caffeine, acetaminophen, some vitamins, pseudoephedrine, and any number of plants and fungus. It is perhaps somewhat more toxic than pure ethanol, but less so than tobacco and many illegal drugs (some such as LSD and marijuana are negligibly toxic). From a purely chemical standpoint, its toxicity is probably on par with lead and other heavy metals. That said, there is no doubt that plutonium may be extremely dangerous when handled incorrectly. The alpha particle 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. 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. 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. It is possibly because of confusion between these two issues that has led to sensationalism of plutonium toxicity. A 1989 paper by Bernard L. Cohen states: :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. ([http://www.environmental.usace.army.mil/info/technical/hp/hpfaq/THE_MYTH_OF_PLUTONIUM_TOXICITY.doc MS Word]) ([http://russp.org/BLC-3.html 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. 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 Roentgen equivalent man (5.1 Sievert) 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) 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 burn 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 [http://tis.eh.doe.gov/techstds/standard/hdbk1081/hbk1081f.html#ZZ39]. To avoid these problems, special precautions are necessary to store or handle plutonium in any form; generally a dry inert atmosphere is required [http://tis.eh.doe.gov/techstds/standard/hdbk1081/hbk1081d.html#ZZ28]. ==References== *[http://periodic.lanl.gov/elements/94.html Los Alamos National Laboratory - Plutonium] * [http://education.jlab.org/itselemental/ele094.html It's Elemental - Plutonium] * [http://www.webelements.com/webelements/elements/text/Pu/index.html WebElements.com - Plutonium] * [http://environmentalchemistry.com/yogi/periodic/Pu.html EnvironmentalChemistry.com - Plutonium] * [http://www.fas.org/nuke/intro/nuke/plutonium.htm Federation of American Scientists - Plutonium production] * [http://nuclearweaponarchive.org/Library/Plutonium/ nuclearweaponarchive.org - Plutonium Manufacture and Fabrication] * ''[http://www.edpsciences.org/journal/index.cfm?v_url=epl/full/2001/16/6673/6673.html Ambient pressure phase diagram of plutonium - A unified theory for α-Pu and δ-Pu]'', P. S�derlind, Europhys. Lett., 55 (4), p. 525 (2001). == External links == * [http://www.ccnr.org/Plute_Anyone.html#Dangers The Dangers of Plutonium] - Anti-nuclear viewpoint * [http://www.ccnr.org/index_plute.html collection of articles on plutonium at the Canadian Coalition for Nuclear Responsibility] * [http://russp.org/BLC-3.html The Myth of Plutonium Toxicity] * [http://www.lanl.gov/worldview/news/releases/archive/00-099.shtml Criticality Accidents Report Issued] * [http://www.nuclearfiles.org/hitimeline/nwa/index.html Nuclear Accidents Timeline] * [http://www.globalsecurity.org/wmd/library/report/crs/97-564.htm Nuclear Weapons: Disposal Options for Surplus Weapons-Usable Plutonium] * [http://www-cms.llnl.gov/s-t/pu-phase_diagram.html Unraveling the Phase Diagram of Plutonium] * [http://www.ieer.org/fctsheet/pu-props.html Physical, Nuclear, and Chemical, Properties of Plutonium] from IEER Actinides Chemical elements

Plutonium

== Information Sources == Some of the text in this entry was rewritten from [http://periodic.lanl.gov/elements/94.html Los Alamos National Laboratory - Plutonium]. Additional text was taken from the Elements database 20001107 (via [http://www.dict.org dict.org]). Data for the table was obtained from the sources listed on the subject page and WikiProject Elements but was reformatted and converted into SI units. == Most dangerous substance known to man == Plutonium is by no stretch of the imagination the most dangerous substance known to man. It will give you cancer if you inhale plutonium dust but that's true for all alpha emiters, and in any event that won't kill you for a few decades. Also removed the stuff about radiological bombs, because plutonium isn't very radioactive (and because it is hard to get), it's not a particularly good material for a dirty bomb especially in comparison with radioactive iodine or cesium. :Well, what IS the most dangerous substance known to man, then, if it's not plutonium? User:Graft :: Off hand, it's guess that maybe a nerve agent like sarin. Also, one could argue that refined plutonium *is* one of the most dangerous substances known to man, not because of its inherent lethality, but because you can build bombs with it and you don't want the stuff lying around where bad people can get it. :::But by that logic so is hydrogen. - User:Omegatron 23:39, Mar 7, 2005 (UTC) :::So, apparently VX has an LD-50 lower than sarin, of .008 mg/kg. Ricin does better at .001 mg/kg. By far the best is the famed botulinum toxin ('botox') at 200 pg/kg. Yow. I remember reading that one molecule of botulinum toxin is sufficient to kill a cell. User:Graft :::: Just on the logic above, about plutonium being the most dangerous substance because you can build bombs with it, that would probably make steel the most "dangerous" substance of all. You can build an a-bomb without plute, but you can't build one without steel. Nor can you build rifles, tanks or warships. Let's remember we're writing an encyclopedia article here. This sort of thing does not belong. User:Andrewa 11:46 Mar 8, 2003 (UTC) :::: Tetanus toxin is in the few tens of ng/kg, some nerve agents are IIRC in the hundreds of ug/kg, and ricin has an average lethal dose of 100 ug (so actually a tad over a/kg). One molecule of ricin can kill a cell, but it has trouble entering, and can meet the wrong structure (eg the lysosome). I don't know about botulinum toxin, but it's under an ng/kg, and lethal doses have been in the several ng. As such, Pu doesn't even come close. Regardless of what the most dangerous substance is, it's certainly not Plutonium. Naturally-occuring Radium is about 200 times more radiotoxic. User:Andrewa 23:31 Mar 7, 2003 (UTC) :I don't remember specific LD-50 data, but plutonium salts are among the most toxic of all inorganic substances. N.B. that's chemical toxicity, not radiotoxicity. User:Mkweise 00:01 Mar 8, 2003 (UTC) ::[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/L/LD50.html LD50] data can't by definition be used to separate chemical and radiological toxicity, it is a measure of the overall effect of the substance. So whatever the source of this information, I'd double-check that you understood them. The other strange thing about this claim is, why focus on inorganics? The organic compounds (which include of course organic salts) of heavy metals (eg lead) are normally the most deadly. Is there any reason for thinking plutonium won't be the same? It will be difficult to find out, as the radiotoxicity is high enough to mask these effects anyway. Plutonium is very nasty stuff. But not as nasty as some people want to make you think. User:Andrewa 11:46 Mar 8, 2003 (UTC) :::My source on that is a nuclear war preparedness manual, ca. 1979, which was handed out to my class back in high school - so it is possible that it's exaggerated. It clearly states that unlike uranium, plutonium kills by (chemical) poisoning long before its radioactivity gets anywhere near dangerous levels. ::::Not wanting to be unkind, but this sounds like a political document. Do you remember who wrote and printed it? ::::: As a further health warning on the above - one of the salient facts about uranium is that it kills by chemical poisoning long before its radioactivity gets anywhere near dangerous levels :::The nasty thing about inorganic toxins is that they accumulate over a lifetime as well as up the food chain. (N.B. organic acid salts of heavy metals are considered inorganic toxins, since the toxic ions are inorganic.) Organic toxins, while dangerous in much lower doses, generally (with a few notable exceptions like dioxins) biodegrade very rapidly, often in a matter of days or even hours. User:Mkweise 03:08 Mar 11, 2003 (UTC) ::::Four problems here. One, the claim was about "inorganic substances", and these don't include organic salts regardless of what "inorganic toxins" might mean. So can we lay that one to rest? Two, some organic salts aren't "organic acid salts", as many metals such as plutonium, uranium and aluminium are amphoteric. Three, some salts (not many but some, and it depends a bit on the definition of a salt which is a bit controversial on this exact issue) don't ionise in food or in the body since they are not soluble in water. Four, it's not obvious what all of this is supposed to prove. ::::Obviously this is a complex and controversial subject, and there's a lot of misinformation and guesswork in existing literature. Beware! User:Andrewa 20:44 Mar 11, 2003 (UTC) :: As regards Pu being one of the worst inorganics, how does it compare to dimethylmercury (organic, granted) or HCN (not sure if it's organic). For that matter, how does it compare to Cd or Hg salts? User:PakaranUser talk:Pakaran 00:02, 10 Aug 2004 (UTC) ---- I see the bit about radiological bombs has been put back in. I'm not going to remove it, for the moment at least. I think it would be good if someone a bit closer to politically neutral on the issue had a look at it. More serious I think is the claim about first aid on the Manhatten project. It sounds like an urban myth to me, and I think it's put there to scare people. But it may be true, funny and horrible things happen in wartime. I have no evidence either way, so again I have not touched it. But maybe someone should. User:Andrewa 23:51 Mar 7, 2003 (UTC) :In the late 1940s a secret project was initiated to evaluate the toxicity of Plutonium and where it concentrated by injecting "Terminally Ill" patients with various amounts of Plutonium salts solutions. Usually the injected limb was amputated within a few weeks and analyzed for distribution of the Plutonium. As these were "Terminally Ill" patients, none were expected to survive more than a few years at most. However a small number of these patients did recover from their original illness, and with no significant obvious problems due to the Plutonium. At least one of these patients was still alive in the late 1980s!!! -- User:RTC 00:05 Mar 8, 2003 (UTC) ::That would give a possible source of this myth, if myth it be. But it doesn't answer the basic question of whether there is some truth in it. I doubt it belongs in the article, myself. User:Andrewa 11:46 Mar 8, 2003 (UTC) ::I know I'm replying to a comment made almost a year ago, but it is worth saying that the plutonium experiments undertaken by Stafford Warren were largely to assess the medical ''benefits'' of injecting plutonium (as a form of primative, direct chemotherapy), at least that was the gist of what I read about what was apparently titled Operation Sunshine (which was the not-fantastic "Plutonium Files" book which focused almost solely on the 'human story' -- important, sure, but not everything). Also, the closest thing to 'plutonium exposure' during the Manhattan Project that I've heard of is the death of a technician by radiation poisoning during experiments on the critical mass of a plutonium sphere (it was (poorly) dramatized by John Cusak in the movie Fat Man and Little Boy), after which said sad technician's body was of course put through extensive autopsy and his head, of all things, got shipped into storage or something along those lines. But I can't seem to remember offhand which book I saw that in... arggg. --User:Fastfission 05:48, 10 Feb 2004 (UTC) :::I agree, true or false, the part about "amputation" does not belong and the proper context of the toxicity data should be made. -- User:RTC 00:39 Mar 11, 2003 (UTC) :Quoting from [http://www.oism.org/cdp/V10_05.htm http://www.oism.org/cdp/V10_05.htm]: The most toxic substances known to man are made by bacteria. Contrary to allegations by PSR, et al., plutonium is ``not a world-class toxicant,'' writes T. Don Luckey in a June 20 letter to Chemical and Engineering News. When injected intraperitoneally into mice, the LD50 (the dose that causes 50% deaths in 30 days) is about the same as that of the vitamin pantothenic acid. On a scale in which plutonium has a toxicity = 1, the toxicities of other materials are: *mercury chloride 100 *strychnine 1,000 *actinomycin D 10,000 *tetrodotoxin 100,000 *perfringens A toxin 1,000,000 *pestis toxin 10,000,000 *shigella toxin 100,000,000 *botulinal E toxin 1,000,000,000 *tetanus toxin 100,000,000,000 *botulinal B toxin 1,000,000,000,000 *botulinal D toxin 10,000,000,000,000 The EPA is more concerned about carcinogens than toxins, but plutonium doesn't make the grade there either. Plutonium-contaminated workers have a lower total cancer mortality: 88% that of unexposed workers. :End quotation -- User:RTC 00:40 Mar 8, 2003 (UTC) ::Is that right? That's surely the result of poor statistics... otherwise you're saying that working with plutonium can help -prevent- dying of cancer. User:Graft :::I suspect the reason for the reduction in mortality is that their employers monitor their health much more closely, so cancers in these workers are usually caught at much earlier and more treatable stages. However that is only a guess. -- User:RTC 22:32 Mar 11, 2003 (UTC) ::::Check out the article on radiation, and the new section on ''radiation hormesis''. This is just a hypothesis, but exposure to small amounts of ionizing radiation may actually ''reduce'' the risk of cancer. User:RK :::::I read it, and it's bullshit. The argument against linear no-threshold dose-response completely misunderstands the two-hit model for cancer generation and doesn't even begin to challenge it. User:Graft ::::::Have you any reasons for thinking hormesis and the two-hit model (I assume you mean Knudson’s work here) aren't compatible? They answer quite different questions. Perhaps this discussion should go to Talk:Radiation. User:Andrewa 18:33 Mar 14, 2003 (UTC) I think what is important is that we try to come to a consensus as to what the key facts are, and what they key opinions are, and try to describe all of these in a readable and approachable way that makes it clear which is which. I've had go! I'm not completely happy with the results but I'm sure they won't last too long! And I think we are making real progress. The key question I think is what is "danger" and what is "toxicity". "Toxicity" can be measured and is a matter of fact. "Danger" is felt and is a matter of opinion. Does this help? I have not been consistent in this usage myself I realise. User:Andrewa 00:24 Mar 12, 2003 (UTC) ----- This set off my BS meter. Moving to talk until/unless someone can list a citation for this. :According to some accounts, the accepted first aid technique for tissue exposure to plutonium during the Manhattan Project was immediate high amputation of the exposed limb. This is unlikely, as the focus of the Manhatten Project was the wartime development of an important weapon and industrial safety was not a high priority. The dangers of other key materials, such as beryllium, were not researched and documented until many years afterwards. ::Should probably be filed in the paper shredder right alongside scram being an acronym for ''safety control rod axe man''. User:PakaranUser talk:Pakaran 00:02, 10 Aug 2004 (UTC) :::I guess "according to some accounts" sounds more reputable than "I read it in a science fiction story"... :::''Plutonium taken into the body moves quickly to bone marrow. Nothing can be done; the victim is finished. Neutrons from it smash through the body, ionizing tissue, transmuting atoms into radioactive isotopes, destroying and killing. The fatal dose is unbelievably small; a mass a tenth the size of a grain of table salt is more than enough-a dose small enough to enter through the tiniest scratch. During the historic "Manhattan Project" immediate high amputation was considered the only possible first-aid measure.'' ::: - Robert Heinlein's short (fiction) story ''The Long Watch'' (full text [http://dragon.rulez.cz/e-buk/Robert%20A.%20Heinlein%20-%20Past%20through%20Tomorrow.pdf here], this story begins around p. 163.) The same story also describes plutonium as ''the most poisonous, and most deadly metal in the known world''. --User:Calair 23:25, 7 Mar 2005 (UTC) --- Rewrote. The toxicity of plutonium really isn't a "controversial topic." I don't know of anyone knowledgeable either in the anti-nuclear movement or outside that will seriously defend a statement that plutonium is magically toxic. :Good rewrite. I'm still concerned that we've gone back to saying the plutonium is a "particularly deadly poison" when the evidence is that nobody ever has or ever will suffer such a fate, and that we've gone back to calling plute weapons a "category" when in fact non-plute weapons have always been rare exceptions, and that we're back to suggesting that plute might be useful as a radiological weapon, when if you blew up some spent nuclear fuel for example the fission products would be a much bigger problem than the plute. But we've made great progress on what the article said just a little while ago. User:Andrewa 02:27 Mar 12, 2003 (UTC) ::However, you should search for HREX site:.gov on the web - there USED to be a website at Argonne/Brookhaven covering human injection experiments of Pu, and they were all primary sources. (I'm not arguing that it's magically dangerous.) Worth putting in the article? But they're gone now, you know, that whole security thing. Kind of a bummer, they were really interesting to read. Maybe someday we won't have an asshat as POTUS. Maybe someone has an archive of them. User:Sword 03:25, 8 Dec 2004 (UTC) ---- :''Because of its low half-life, there are only extremely tiny trace amounts of plutonium naturally.'' Someone more knowledgable than I - I've been given to understand that transuranium elements simply don't occur at all naturally. Is this just a convenient oversimplification for the layperson? Is the above statement accurate? User:Graft :It does occur in uranium ores, due to occasional neutron capture by U-238 followed by decay to Np-239 and Pu-239. But as these events are VERY infrequent (they depend on spontanious fission rate of U-235 as well as neutron capture cross section of U-238) compared to the half-life of Pu-239, the levels can be practically ignored. I don't remember exact figures, but as I understand it the total amount of "naturally occuring" Plutonium in the entire earth is measureable in micro-gram quantities. The amount mankind has manufactured in reactors is many tons. -- User:RTC 02:30 Mar 14, 2003 (UTC) :The explanation is that as analytical techniques improve, previously undetectable quantities become detectable. I don't think there's any proposal to change the status of plutonium to "natural" rather than "artificial", but that's only one of several reasons that this distinction has now blurred a little. Two others are the recognition that plutonium was once more common on earth than it is now, and the discovery of natural "[http://www.curtin.edu.au/curtin/centre/waisrc/OKLO/index.shtml fossil reactor]" sites in Gabon. User:Andrewa 17:20 Mar 14, 2003 (UTC) :Actually, any plutonium detected by "analytical techniques" is almost certainly contamination from unfissioned plutonium in the fallout from the 1940s through 1960s bomb tests. Even in modern uranium ores (as far as I know) the "naturally occuring" levels are estimates based on spontanious fission rates, capture cross sections, and decay rates. -- User:RTC 19:09 Mar 17, 2003 (UTC) :Webelements says "Plutonium is found in trace quantities in uranium ores but, in practice, normally it is synthesised by the transmutation of uranium. However, it is now found in very small quantities in some areas as a result of fallout from atomic bombs and from radiation leaks from nuclear facilities." I thought that mass spectrometers were now sensitive enough to detect the plutonium in uranium ores, but I could be wrong. This would not be contamination if so, as there hasn't yet been time for man-made plute to invade the geology to this extent. User:Andrewa 21:25 Mar 17, 2003 (UTC) Uhm, where do we get botulin toxin (lethal dose in the ng/kg range) as being "billions of times more toxic than plutonium?" That would imply that one can survive several g/kg of plutonium, making it safer than caffeine? A gram of plutonium is probably a lethal dose I'd say, especially in soluble form. User:PakaranUser talk:Pakaran 04:29, 1 Mar 2004 (UTC) : According to [http://russp.org/BLC-3.html this page], the author challenged Ralph Nader to consume as much caffeine as the author would plutonium. --User:NeuronExMachina 07:38, 6 Aug 2004 (UTC) :: See my last edit to the article. I put the toxicity issues in context. Let me know what you think. User:PakaranUser talk:Pakaran 23:55, 9 Aug 2004 (UTC) : I personally think it's a lot clearer now. It may need some slight NPOV tweaking, though. --User:NeuronExMachina 01:48, 10 Aug 2004 (UTC) ----- I've converted this over to the Wikipedia:WikiProject Elements format. Unfortunately, I've been interrupted and will have to leave it for now having made the table and folded the old text into the standardised headings format (with a few minor modifications to alter the flow -- I hope they haven't upset anybody with a strong view on the toxicity issue, but you may want to check through). Still to do: * Make the custom Plutonium image * Expand the text with the various bits and bobs that are usually put into elements. * Try and chase down alternate sources of data for some of the stuff that I couldn't find for the table. Sources of data used in the table were [http://www.webelements.com webelements.com] and [http://www.environmentalchemistry.com environmentalchemistry.com]. I will try and come back to this in the next few days if no one else sorts it out first. -- User:Bth 14:02, 6 Mar 2004 (UTC) :OK, the image still needs doing, but it's not the only one of the Wikipedia:WikiProject Elements to need that ... --User:Bth 16:10, 9 Mar 2004 (UTC) ---- Recent added paragraph: "Orally, plutonium is less toxic than several common substances, including caffeine, acetominopnen, some vitamins, (pseudo)ephedrine, all narcotic pain killers (including codeine) and any number of plants and fungi. It is perhaps somewhat more toxic than absolute alcohol, but less so than tobacco and most illegal drugs (some such as LSD and marijuana are not or barely toxic). As such, it is debatable whether plutonium should even be classified as a poison." This seems almost ridiculously exaggerated. Supporting quantitative evidence should be provided or it should be deleted if none can be cited. :I think the above statement is self-evident, especially with respect to aspirin, a dangerous substance that would be a precription drug if it were not grandfathered in. What is happening is that there is conflation with plutonium's use in bombs. Now radium, that is dangerous. User:Fred Bauder 11:59, Aug 10, 2004 (UTC) ---- It is great so much effort has gone into creating a fine treatment of plutonium toxicity, but does it belong on the plutonium page anymore? 5 paragraphs seems out of proportion to the rest of the article, which ought to be a mundane element page talking about melting points and isotopes. Any reason I shouldn't say "plutonium is toxic, but no especially so." and cut and paste the rest into Plutonium Toxicity? :I think that's an excellent idea. There's still a lot of weasel-talk in the current article. Basically, some people still don't want to admit that the plute toxicity myth was and is both deliberate propaganda and a whopping big lie. The problem here is, the facts make this painfully obvious, but some significant public figures have attached their names to the myth just the same. :Criticality and proliferation issues aren't connected to toxicity except in a political sense. Ideally, we'd move all the politics into another article, perhaps Plutonium and politics, and battle out an NPOV presentation of these issues there. User:Andrewa 00:37, 5 Oct 2004 (UTC) :I wonder if the name has any bearing on the image of Plutonium. It does sound vaguely similar to Pollution ( "Pollute-tonium"). Just a thought. ==Vandalism - a suggestion== This talk page was vandalised by a couple of anons, who deleted sections out of some of my posts to render them nonsensical. I guess they didn't like what I said, and I think I can understand that. Telling lies about plutonium is something of an industry all of its own, and accurate Wikipedia articles threaten it. Not that this article is perfect by any means! Lots of weasel-words in there still. That's why I think this talk page is important (and so do others, obviously). I think I've got it back to rights. It wasn't a simple revert as there had been good-faith contributions in the meantime which I didn't want to lose, or even complicate their histories as at least one is unsigned. And I guess it will happen again, so I suggest anyone updating this page check for recent vandalism, and make your update to the last unvandalised version, which will painlessly revert the corruption. User:Andrewa 10:50, 18 Jan 2005 (UTC) =="complete"== What does "Complete" mean in the sentence: "Complete detonation of plutonium will produce an explosion of 20 kiloton per kilogram."? It could be taken to mean total fission of the Pu into daugher nuclei. This would release a phenomenally huge amount of energy. Much more than 20kt/kg wouldn't it? I understand this is partially done with tritium boosting.--User:Deglr6328 00:46, 19 Jan 2005 (UTC) :I took it to mean fissioning of all the Pu nuclei. To check its reasonableness empirically, we could try to find figures as to the efficiency, yield and pit mass of a pure plutonium detonation, such as little boy or the trinity test. Or theoretically, I guess the figure given is just the energy release per fission (there's about 220 mev of binding energy release, which doesn't count subsequent radioactive decay which is significant in a reactor but probably not here) multiplied by the number of atoms per kilogram, so we could reperform this calculation. Can you take it from there? What leads you to believe the figure given is ''not'' reasonable? :Tritium is used for two purposes: It's a fuel for the easiest (lowest temperature and pressure) fusion reaction, and it's used as a neutron source to boost the efficiency of predominantly fission bombs. It's the second role you are describing here, and as you imply, it doesn't result in perfect efficiency by any means. User:Andrewa 19:56, 19 Jan 2005 (UTC) ::hm. one Kg Pu239 = 4.184 mol = 2,519,665,271,966,527,196,652,720 atoms * 220MeV= 5.543263598X10^32 eV= 88,812,864,488,134 J= 21.22 Kt TNT...........huh...whadda know...just seemed too low I guess. ::Anyway, the previous sentence "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." should specify the isotope that this is true for....I don't know it but prolly 239, yes?--User:Deglr6328 07:56, 20 Jan 2005 (UTC) --- occurrence Dalrymble in book The Age of the Earth,1991, lists many isotopes as evidence of old earth. All isotopes t1/2>80 Myr are found in nature. Pu-244 is among them. Clearly originate from supernovae and stars just like other permanent elements (uranium, iron etc) on earth. Isotopes t1/2 <80 million yrs not found unless result of some continuing nuclear process (like short live Radon-222 from uranium etc). --MrKAT ,6 Feb 2005. One of the problems faced by the Manhattan Project was constraining the fissile material for as long as possible before it blew itself apart. Unfortunately, that is still a constraint on obtaining anywhere near the theoritical maximum available energy. And, in discussing critical mass, I've seen reports where the critical mass of Pu-239 was as low as 200 grams using an ideal Beryllium reflector. The Beryllium aids by adding large numbers of photo neutrons to the process. == Why reactor-grade plutonium is unsuitable for making a bomb == I thought appropriate to point out that small contents of 240Pu make the material proliferation-resistant, and why. --User:Philipum 12:01, 24 May 2005 (UTC)

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