Plutonium (Pu) meaning

In legal practice, plutonium (Pu) denotes a controlled nuclear material whose possession, use, storage, transport and export attract stringent licensing, safeguards and security duties. It is a heavy, radioactive, man‑made metal (atomic number 94) with numerous isotopes; Pu‑239 is the most commercially significant, being fissile with slow (thermal) neutrons. The term itself is descriptive; legislation regulates it by reference to “nuclear material” or “special fissile material”. In the UK, plutonium is nuclear material for the purposes of the Nuclear Material (Offences) Act 1983 (implementing the CPPNM) and is subject to safeguards under the Nuclear Safeguards Act 2018. For 1983 Act offences, “nuclear material” includes plutonium other than plutonium with more than 80% Pu‑238. Environmental authorisation for keeping or disposing of plutonium‑bearing radioactive substances is governed by the Environmental Permitting (England and Wales) Regulations 2016, the Environmental Authorisations (Scotland) Regulations 2018, and the Radioactive Substances Act 1993 in Northern Ireland. The Office for Nuclear Regulation oversees security and transport compliance. In Ireland, plutonium is regulated by the EPA under the Radiological Protection Acts and related EU/Euratom law, where it is treated as “special fissile material”. Usage and compliance expectations are broadly consistent across all four jurisdictions.