Plutonium is one of the major elements historically employed in the development of nuclear weapons. It is the key fissile material in most modern nuclear arms, with 1 kilogram of the specific plutonium isotope P-239 equivalent upon detonation to 10,000 tons of conventional explosive.
Plutonium has been used in nuclear weapons since the very beginning of their development in the United States and worldwide. It was critical for the testing conducted by Robert Oppenheimer and his team at Las Alamos during World War II. Additionally, plutonium has seen application in the development of radiological weapons, as well as in the development of what are called "fast-breeder" nuclear weapons, which use a mixed oxide fuel containing both plutonium and uranium.
Plutonium isotope 238 is an alpha emitter that possesses a half life of approximately 87 years. This extended potency makes this particular isotope highly valuable for supplying power to devices that require long periods without human maintenance or intervention or devices that have tasks or applications vastly longer than normal human life expectancy. Consequently, plutonium has been used in conjunction with aerospace applications, such as in the unmanned probes Galileo and Cassini. Plutonium was also used to power seismic devices and other tools carried by Apollo 14 in 1971. It was the chief power supply for the two 1977 Voyager craft.
Additional historical experimentation with plutonium has investigated its use in powering artificial heart pacemakers and in providing supplemental heat to scuba divers. In physics and chemistry settings, plutonium has proven an effective agent in creating neutrons when mixed with beryllium.