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Moreover, 239 Pu and 240 Pu cannot be chemically distinguished, so expensive and difficult isotope separation would be necessary to separate them. Weapons-grade plutonium is defined as containing no more than 7% 240 Pu; this is achieved by only exposing 238 U to neutron sources for short periods of time to minimize the 240 Pu produced.
In contrast, the generic civilian Pressurized water reactor, routinely does (typical for 2015 Generation II reactor) 45 GWd/tU of burnup, resulting in the purity of Pu-239 being 50.5%, alongside a Pu-240 content of 25.2%, [5] [6] The remaining portion includes much more of the heat generating Pu-238 and Pu-241 isotopes than are to be found in ...
Plutonium is a chemical element; it has symbol Pu and atomic number 94. It is a silvery-gray actinide metal that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibits six allotropes and four oxidation states. It reacts with carbon, halogens, nitrogen, silicon, and hydrogen.
The most stable are 244 Pu with a half-life of 80.8 million years; 242 Pu with a half-life of 373,300 years; and 239 Pu with a half-life of 24,110 years; and 240 Pu with a half-life of 6,560 years. This element also has eight meta states ; all have half-lives of less than one second.
In a fission nuclear reactor, uranium-238 can be used to generate plutonium-239, which itself can be used in a nuclear weapon or as a nuclear-reactor fuel supply. In a typical nuclear reactor, up to one-third of the generated power comes from the fission of 239 Pu, which is not supplied as a fuel to the reactor, but rather, produced from 238 U. [5] A certain amount of production of 239
Pu, and eventually fissile 239 Pu and heavier isotopes of plutonium. The 237 Np can be removed and stored as waste or retained and transmuted to plutonium, where more of it fissions, while the remainder becomes 242 Pu, then americium and curium, which in turn can be removed as waste or returned to reactors for further transmutation and fission.
Pu-238 is an alpha emitter (so too is the bomb-grade Pu-239). Alpha particles can be stopped by paper. Indeed, you don’t want to inhale the stuff. But when they brought the 5 kg Pu-239 core to New Mexico for the Trinity shot, one of the physicists held it in his hand. It was even slightly warm because of the slight alpha radiation it was ...
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