23 February 1941

Plutonium is first produced and isolated by Dr. Glenn T. Seaborg.
Plutonium is a radioactive metallic chemical element with the symbol Pu and atomic number 94. It is a member of the actinide series of elements, which are known for their radioactivity and many of which are synthetic. Plutonium is typically produced in nuclear reactors through the irradiation of uranium-238.

Discovery: Plutonium was first synthesized by Glenn T. Seaborg, Edwin McMillan, Joseph W. Kennedy, and Arthur Wahl in 1940 at the University of California, Berkeley. They bombarded uranium-238 with deuterons (nuclei of heavy hydrogen, or hydrogen-2) to produce neptunium-238, which then underwent beta decay to form plutonium-238.

Isotopes: Plutonium has several isotopes, but plutonium-239 is the most important one from a practical standpoint. It is fissile, meaning it can sustain a nuclear chain reaction, making it useful for both nuclear power and nuclear weapons. Plutonium-239 has a half-life of about 24,100 years.

Nuclear Weapons: Plutonium-239 is a key component in nuclear weapons. It can be used in both fission and fusion bombs.
Nuclear Power: Plutonium-239 is also used as fuel in some types of nuclear reactors, particularly in breeder reactors where it can be bred from uranium-238. However, its use in civilian nuclear power is less common compared to its military applications.
Radioisotope Thermoelectric Generators (RTGs): Plutonium-238, which is produced in small quantities, is used as a heat source in RTGs for space missions, satellites, and remote terrestrial applications.

Radioactivity: Plutonium is highly radioactive and poses significant health risks if mishandled. Its decay products emit alpha particles, which can be stopped by a sheet of paper or even skin, but can be highly damaging if inhaled or ingested.

Hazards: Plutonium is toxic and can pose both chemical and radiological hazards. Inhaling or ingesting even small amounts can lead to serious health problems, including cancer. Proper handling and storage are essential to minimize risks.

Production: While plutonium can be produced in nuclear reactors, it can also be synthesized in particle accelerators or by neutron irradiation of other elements.

Due to its role in nuclear weapons and its potential use in nuclear proliferation, plutonium is subject to strict controls and safeguards under international agreements such as the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).