Plutonium242

Plutonium-242 (Pu-242) is a radioactive isotope of the actinide element plutonium. It has 94 protons and 148 neutrons, giving it a mass number of 242. Pu-242 is synthetic, produced in nuclear reactors by neutron capture on lighter plutonium isotopes, typically starting from Pu-239 or Pu-241, with subsequent captures and decays yielding Pu-242.

Pu-242 decays primarily by alpha emission to uranium-238. It has a long half-life of about 375,000 years, making it one of the longer-lived plutonium nuclides. Because of its longevity and relatively low production, Pu-242 is not used as a fuel or in weapons applications. It occurs mainly as a minor, persistent contaminant in reactor-grade plutonium and in spent nuclear fuel.

In terms of nuclear behavior, Pu-242 is not fissile with thermal neutrons; it can undergo fission with fast neutrons to a limited extent. Its presence increases the complexity of isotopic compositions in reprocessed materials and can influence radiological assessments of aged plutonium stocks. Chemically, Pu-242 behaves like other plutonium isotopes, forming common compounds such as plutonium dioxide (PuO2) and various oxides, with oxidation states ranging over the usual plutonium chemistry.

Safety and handling considerations reflect its classification as a long-lived alpha emitter. External exposure is generally less hazardous, but inhalation or ingestion can lead to significant internal dosimetry. Long-term storage and containment are needed to minimize environmental release and radiological risk.