The fissioning of an atom of uranium-235 in the reactor of a nuclear power plant produces two to three neutrons, and these neutrons can be absorbed by uranium-238 to produce plutonium-239 and other isotopes. Plutonium-239 can also absorb neutrons and fission along with the uranium-235 in a reactor.

Is plutonium-239 man made?

It was discovered in 1940 by scientists studying how to split atoms to make atomic bombs. Plutonium is created in a reactor when uranium atoms absorb neutrons. Nearly all plutonium is man-made.

Is plutonium-239 naturally occurring?

The isotope Pu-239 was produced on March 28, 1941 by bombarding a U-238 target with neutrons to produce U-239 (half-life of 23.5 minutes). ... Thus, we have plutonium produced naturally in the environment (admittedly in trace quantities).