出典:Wikipedia
出典:『Wikipedia』 (2011/07/27 17:30 UTC 版)
Neptunium ( /nɛpˈtjuːniəm/ nep-tew-nee-əm) is a chemical element with the symbol Np and atomic number 93. A radioactive metal, neptunium is the first transuranic element and belongs to the actinide series. Its most stable isotope, 237Np, is a by-product of nuclear reactors and plutonium production and it can be used as a component in neutron detection equipment. Neptunium is also found in trace amounts in uranium ores due to transmutation reactions.