 Plutonium-242

Plutonium-242 (242Pu) is one of the isotopes of plutonium, the second longest-lived, with a half-life of 373,300 years.The half-life of 242Pu is about 15 times longer than that of 239Pu; therefore, it is one-fifteenth as radioactive, and not one of the larger contributors to nuclear waste radioactivity.