Title: plutonium | Infoplease
Headings: plutonium
plutonium
Content: It dissolves in hydrochloric, hydriodic, and perchloric acids and reacts with the halogens, carbon, nitrogen, and silicon. Pure plutonium metal may be prepared by reduction of the trifluoride, PuF 3, with calcium metal. Sixteen isotopes of plutonium are known. The most stable is plutonium-244 (half-life about 82 million years). By far the most important is plutonium-239 (half-life about 24,000 years), a nuclear fission fuel. Plutonium-239 is produced in large quantities in nuclear reactors from uranium-238, an abundant but nonfissionable isotope. Uranium-238 absorbs neutrons emitted by the fission of uranium-235; uranium-239 is formed, which emits a beta particle and decays to neptunium-239; the neptunium-239 emits another beta particle, becoming plutonium-239. Once begun, the reaction proceeds spontaneously until the uranium fuel rods in the reactor are converted to a certain uranium-plutonium mixture.