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.
The Manhattan Project "Fat Man" type plutonium bombs, using explosive compression of Pu to significantly higher densities than normal, were able to function with plutonium cores of only 6.2 kg.
Magnesium oxide sand is the most effective material for extinguishing a plutonium fire.
Plutonium is an inner transition metal of the actinide series, located in period 7 of the periodic table, between neptunium and americium.
The 1986 Chernobyl accident caused a major release of plutonium.
Extremely fine particles of plutonium (on the order of micrograms) can cause lung cancer if inhaled.
Plutonium also readily shifts valences between the +3, +4, +5 and +6 states.
Complete detonation of plutonium will produce an explosion equivalent to the explosion of 20 kilotons of trinitrotoluene (TNT) per kilogram.
The "live oaks" (oaks with evergreen leaves) are not a distinct group, instead with their members scattered among the sections below.
All isotopes and compounds of plutonium are toxic and radioactive.
Plutonium-239 is one of the three fissile materials used for the production of nuclear weapons and in some nuclear reactors as a source of energy.
Plutonium in solution is more likely to form a critical mass than the solid form (due to moderation by the hydrogen in water).
Plutonium could also be used to manufacture radiological weapons or as a radiologic poison.
Naturally occurring radium is about 200 times more radiotoxic than plutonium, and some organic toxins like botulin toxin are still more toxic.
The most important isotope of plutonium is 239Pu, with a half-life of 24,110 years.
When taken in by mouth, plutonium is less poisonous (except for risk of causing cancer) than several common substances including caffeine, acetaminophen, some vitamins, pseudoephedrine, and any number of plants and fungi.
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.
The insistence on both sides of the issue of plutonium's safety/deadliness casts questions on the current habitability of areas that have been exposed to nuclear warfare and on the health of the current residents.
On the other hand, 5 kg of plutonium was spread over the Nagasaki area (due to incomplete fission) and never cleaned up.
Plutonium reacts readily with oxygen, forming PuO and PuO2, as well as intermediate oxides.
To avoid these problems, special precautions are necessary to store or handle plutonium in any form; generally a dry inert atmosphere is required.
Plutonium was also used in the "Fat Man" bomb dropped on Nagasaki, Japan in August 1945.
The heat given off by alpha particle emission makes plutonium warm to the touch in reasonable quantities.
The isotopes of plutonium range in atomic weight from 228.0387 u (Pu-228) to 247.074 u (Pu-247).
Plutonium expands considerably in size as it oxidizes and thus may break its container.
The presence of these many allotropes makes machining plutonium very difficult, as it changes state very readily.
Large stockpiles of plutonium were built up by both the Soviet Union and the United States during the Cold War—it was estimated that 300,000 kg of plutonium had been accumulated by 1982.
So far, however, no human is known to have died immediately died after inhaling or ingesting plutonium, and many people have measurable amounts of plutonium in their bodies.
The alpha radiation it emits does not penetrate the skin, but can irradiate internal organs when plutonium is inhaled or ingested.
A relatively high concentration of plutonium was discovered at the natural nuclear fission reactor in Oklo, Gabon in 1972.
That said, there is no doubt that plutonium may be extremely dangerous when handled incorrectly.
Plutonium consisting of more than about 90 percent Pu-239 is called weapon-grade plutonium; plutonium obtained from commercial reactors generally contains at least 20 percent Pu-240 and is called reactor-grade plutonium.
Uranium-238 is present in quantity in most reactor fuel; hence plutonium-239 is continuously made in these reactors.
Pu-240 contamination is the reason plutonium weapons must use an implosion design.
One proposal to dispose of surplus weapons-grade plutonium is to mix it with highly radioactive isotopes (e.g., spent reactor fuel) to deter handling by potential thieves or terrorists.
Toxicity issues aside, 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's.
Botulin toxin, in particular, has a lethal dose of 300 pg per kg of body weight, far less than the quantity of plutonium that poses a significant cancer risk.
Metallic plutonium is also a fire hazard, especially if the material is finely divided.