About Uranium and Plutonium

Uranium is a silvery white element that has 92 protons and electrons. Almost 99.3% of naturally found Uranium is the isotope U-238 and the other 0.7% is the isotope U-235. Both of these decay slowly emitting alpha particles in an attempt to become a stable isotope.
Uranium-235 was in high demand during the Manhattan Project as it was needed to produce the large explosion. This was because unlike U-238, U-235 was fissile which means that it is capable of sustaining a nuclear reaction.




Plutonium is the other element that was used in manufacturing on atomic bombs in the Manhattan Project. It has an atomic number of 94 and also emits alpha particles fairly slowly. The plutonium used in the atomic bombs was the isotope Pu-239 and is fissile. Since natural Plutonium sources are so scarce, the only way to get large amounts of it was through using a nuclear reactor. This is achieved when U-238 is bombarded with neutrons and is converted or transmuted into U-239. The U-239 then rapidly decays into Pu-239, but only a small amount of the U-238 is transformed so the Pu-239 must be chemically seperated