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?
Where does it come from? What form is it in? What does it look like? How can it hurt me? To receive email updates about this page, enter your email address: Email Address. All 15 plutonium isotopes are radioactive, because they are to some degree unstable and therefore decay, emitting particles and some gamma radiation as they do so.
All plutonium isotopes are fissionable with fast neutrons, though only two are fissile with slow neutrons. For this reason all are significant in a fast neutron reactor FNR , but only one — Pu — has a major role in a conventional light water power reactor. The most common plutonium isotope formed in a typical nuclear reactor is the fissile Pu, formed by neutron capture from U followed by beta decay , and which when fissioned yields much the same energy as the fission of U In a fast reactor this proportion is much less.
The approximately 1. Examples of the types of variation in plutonium composition produced from different sources 1. Plutonium is the second most common isotope, formed by neutron capture by Pu in about one-third of impacts. 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. Since the early s after production ceased at Savannah River in , the USA was buying all its supply for spacecraft from Russia — some INL supplies the neptunium and does some of the irradiation.
It uses the High Flux Isotope Reactor, irradiating neptunium targets for 72 days. But if people were indeed exposed to the radioactive waste containing plutonium and uranium , what health risks would they face? And how can people minimize their risk of exposure? All radioactive material, as it decays, can cause harm. As unstable radioactive isotopes, or versions of an element with different molecular weights, decay into slightly more stable versions, they release energy.
This extra energy can either directly kill cells or damage a cell's DNA, fueling mutations that may eventually lead to cancer. Plutonium, one of the radioactive substances that may be present at the Hanford site, has a half-life of 24, years, meaning that's how long it takes for half of the material to decay into more stable substances. As such, it sticks around in the environment, and in the body, for a long time. Plutonium exposure can be very deadly for living creatures. A study in the journal Nature Chemical Biology found that rat adrenal-gland cells ferried plutonium into the cells; the plutonium entered the body's cells largely by taking the natural place of iron on receptors.
That study found that plutonium also can linger preferentially in the liver and blood cells, leaching alpha radiation two protons and neutrons bound together. When inhaled, plutonium can also cause lung cancer.
However, because the human body still slightly prefers iron to plutonium for its biological processes, that preference could potentially provide avenues for treating plutonium exposure, by flooding such receptors and preventing plutonium from being taken in by the cells, the study authors noted.
In addition, a study in the journal Current Medicinal Chemistry found that there are some short-term treatments for plutonium exposure. Studies in the s and s identified agents, such as Diethylenetriaminepentaacetic, which can help the body remove plutonium faster.
Other drugs, such as ones used to treat iron-processing disorders such as beta-thalassemia, or bone-strengthening drugs that treat osteoporosis, may also be useful for plutonium exposure, the study found.
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