Plutonium is a heavy, radioactive metal with the atomic number 94. It is primarily used as fuel in nuclear reactors and in the production of nuclear weapons. Discovered in 1940, plutonium is a key element in the field of nuclear science and energy. Plutonium is produced through the irradiation of uranium in nuclear reactors. It has several isotopes, with plutonium-239 being the most significant for its use in nuclear applications. Due to its radioactivity, plutonium must be handled with care to prevent exposure and contamination.