What is plutonium used for?
Plutonium-239 is used to make nuclear weapons. For example, the bomb dropped on Nagasaki, Japan, in 1945, contained Pu-239. The plutonium in the bomb undergoes fission in an arrangement that assures enormous energy generation and destructive potential. The isotope, plutonium-238, is not useful for nuclear weapons. However it generates significant heat through its decay process, which make it useful as a long-lived power source. Using a thermocouple, a device that converts heat into electric power, satellites rely on plutonium as a power source. Tiny amounts also provide power to heart pacemakers. Some foreign countries mix isotopes of plutonium and uranium to manufacture special reactor fuel called mixed-oxide fuel, for commercial nuclear power reactors. The plutonium increases the power output. The U.S. does not currently manufacture mixed-oxide fuel, but is funding research in this type of reactor fuel as a means of dealing with excess plutonium in U.S. stockpiles.
