Plutonium

By: Dave Backwater

People must understand that science is inherently neither a potential for good nor for evil. It is a potential to be harnessed by man to do his bidding. Glenn T. Seaborg Never before has man had such capacity to control his own environment... We have the power to make this the best generation of mankind in the history of the world or to make it the last. John F. Kennedy

Plutonium is a radioactive chemical element. It is the fifth member of the Actinide Series of the periodic table. Its symbol is Pu, and its atomic number is 94. The Average atomic weight is 239.13, however, the most stable plutonium isotope is plutonium 244. The name is derived from the planet Pluto. Plutonium was the second transuranium element, after neptunium, of the actinide series to be discovered. Glenn Seaborg and his associates created the isotope of plutonium 238 in 1940. This was done by bombarding uranium with deuterons in the cyclotron in Berkeley, California. Seaborg's group created the isotope with mass 239 in 1941. In recent years, trace quantities of natural plutonium have been found in uranium ores.

Plutonium is a metal that is silvery in appearance, but it becomes yellowish when exposed to air. It exists in six allotropes, or structural forms, which vary according to temperature. Large pieces of plutonium are warm to the touch due to the release of energy from alpha-particle decay. The pure metal is prepared by the decomposition of plutonium trifluoride by alkaline earth metals. Plutonium is chemically reactive, and will dissolve in concentrated hydrochloric acid, hydriodic acid, or perchloric acid. Plutonium tends to form colored ions, and has a stable oxidation state of +3, however it also has oxidation states of +4, +5, and +6, each ion having a characteristic color in aqueous solution. It also forms halides, oxyhalides, and compounds with carbon, nitrogen, silicon, and sulfur. It forms alloys with uranium, beryllium, nickel, lead, chromium, iron, and manganese.

Nuclear reactors, espicially in Europe and Asia, create electrical power using plutonium 239 as fuel. Various isotopes of plutonium are starting materials in the synthesis of other transuranium elements. It is also used for the manufacture of radioactive isotopes for medical research and industrial purposes. An example is batteries in implanted heart pacemakers, which are powered by the alpha decay of plutonium.

Because the element is absorbed specifically by bone marrow in humans, and because it emits alpha particles at a high rate, plutonium is a highly dangerous radiological poison. Because of this, the possibility of plutonium contamination of water near nuclear power plants has caused public concern.

Plutonium is perhaps best know for it's uses in nuclear weaponry, beginning with the "Fat Man" dropped on Nagasaki in 1945. Since then, It has been used in warheads of long and short range missiles. These missiles, controlled primarily by the United States, the states of the former Soviet Union, France, China, and India were the fuel of the cold war. Plutonium 239 is used in both conventional fission warheads, and as an activator to create extreme temperatures and pressures, which start the fusion of hydrogen into helium in the hydrogen bomb.