Once plutonium circulates through the body, it concentrates in the bones, liver, and spleen, exposing these organs to alpha particles.
Plutonium that is ingested from contaminated food or water does not pose a serious threat to humans because the stomach does not absorb plutonium easily and so it passes out of the body in the feces.
Skip directly to site content Skip directly to page options Skip directly to A-Z link. Radiation Emergencies. Section Navigation. Facebook Twitter LinkedIn Syndicate. Radioisotope Brief: Plutonium. Minus Related Pages. What is it used for? Its concentration in nuclear fuel builds up steadily, since it does not undergo fission to produce energy in the same way as Pu In a fast neutron reactor it is fissionable c , which means that such a reactor can utilize recycled plutonium more effectively than a LWR.
While of a different order of magnitude to the fission occurring within a nuclear reactor, Pu has a relatively high rate of spontaneous fission with consequent neutron emissions.
This makes reactor-grade plutonium entirely unsuitable for use in a bomb see section on Plutonium and weapons below. This is also called 'civil plutonium'. Plutonium, Pu and Pu emit neutrons as a few of their nuclei spontaneously fission, albeit at a low rate.
They and Pu also decay, emitting alpha particles and heat. A MWe light water reactor gives rise to about 25 tonnes of used fuel a year, containing up to kilograms of plutonium. If the plutonium is extracted from used reactor fuel it can be used as a direct substitute for U in the usual fuel, the Pu being the main fissile part, but Pu also contributing.
Plutonium can also be used in fast neutron reactors, where a much higher proportion of Pu fissions and in fact all the plutonium isotopes fission, and so function as a fuel. As with uranium, the energy potential of plutonium is more fully realized in a fast reactor.
Four of the six 'Generation IV' reactor designs currently under development are fast neutron reactors and will thus utilize plutonium in some way see page on Generation IV Nuclear Reactors.
In these, plutonium production will take place in the core, where burn-up is high and the proportion of plutonium isotopes other than Pu will remain high. In pure form plutonium exists in six allotropic forms or crystal structure — more than any other element. As temperature changes, it switches forms — each has significantly different mechanical and electrical properties.
One is nearly twice the density of lead The alpha phase is hard and brittle, like cast iron, and if finely divided it spontaneously ignites in air to form PuO 2. Beta, gamma and delta phases are all less dense. Alloyed with gallium, plutonium becomes more workable.
Russia has maintained a positive policy of civil plutonium utilization. Apart from its formation in today's nuclear reactors, plutonium was formed by the operation of naturally-occurring nuclear reactors in uranium deposits at Oklo in what is now west Africa, some two billion years ago. Civil plutonium stored over several years becomes contaminated with the Pu decay product americium see page on The Many Uses of Nuclear Technology , which interferes with normal fuel fabrication procedures.
After long storage, Am must be removed before the plutonium can be used in a MOX fuel fabrication plant because it emits intense gamma radiation in the course of its alpha decay to Np The European Space Agency is paying NNL to produce Am for watt e radioisotope thermoelectric generators RTGs using very pure Am recovered from old civil plutonium, as the isotope is much less expensive than Pu now scarce.
Of some 2, types of radioisotopes known to humankind, only 22 are capable of powering a deep-space probe, according to a study by the US National Academy of Sciences. Of these, all but Pu are problematical due to being too expensive, emitting too much radiation to work with, or lacking enough heat output however, note European use of Am in above section on Plutonium and americium.
The decay heat of Pu 0. These spacecraft have operated for over 35 years and are expected to send back signals powered by their RTGs through to The Cassini spacecraft carried three generators with 33 kg of plutonium oxide providing watts power as it orbited around Saturn, having taken seven years to get there. See also information page on Nuclear Reactors and Radioisotopes for Space. Plutonium is made by irradiating neptunium, recovered from research reactor fuel or special targets, in research reactors.
Np is formed and quickly decays to Pu Pu was then recovered by further reprocessing at the H Canyon plant there. This was essentially Cold War-origin material. Currently, supplies of high-purity Pu are scarce. Other dangers, but for which there is less data, come from exposure to plutonium through ingestion or through an open wound.
Plutonium is only eliminated from the body very slowly, though excretion. It takes around 50 years for plutonium to be biologically removed from the skeleton and about 20 years for it be eliminated from the liver, says the IRSN. At least two of these sites had isotopes where there was a "high possibility" of a connection to the accident.
But no sample was of a level of contamination that was hazardous for health, it said. France's Nuclear Safety Authority ASN described the data as being in the same category as "background levels" that are a legacy of atmospheric nuclear bomb tests.
Around four tonnes of plutonium were released into the global environment before atmospheric testing ended. This is unclear. Alternatively, it could have come as a fissile byproduct from burning uranium in the No.
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