Plutonium is a radioactive element with the symbol Pu and atomic number 94. It is a silvery-white metal that tarnishes in air, and is extremely radioactive. Plutonium is primarily used in nuclear weapons and nuclear reactors, and is also used in some medical applications. Plutonium is not naturally occurring, and is instead produced by the irradiation of uranium in a nuclear reactor.
Plutonium is a very dangerous substance, and its handling and storage is strictly regulated. Plutonium is also a very valuable material, and its theft and smuggling is a serious concern. Plutonium is a key component in nuclear weapons, and its proliferation is a major threat to global security.