Question

Plutonium-239 can be used to make nuclear weapons and is found in nuclear waste, but radioactive waste from nuclear reactors contains large amounts of undesirable contaminants. Radioactive waste can be stored in deep geological storage. Over many years the fission products decay, decreasing the radioactivity of the waste. However, the undesirable contaminant Pu-240 decays faster than the Pu-239, and thus the quality of the bomb material increases with time. In order for weapons grade plutonium to be obtained the sample must contain 93% Pu-239. If the radioactive waste contains 10% Pu-239 (half-life of 24,110 years) and 90% Pu-240 (half-life of 6561 years), then how long would it take for the reactor grade plutonium to decay into weapons grade plutonium?

Answer 1