Guy Bauman, age 14, of Cleveland Heights, Ohio, for his question:
How do they create plutonium?
Plutonium is a man made element and the creation of new atoms is always a very dynamic event. The creation of plutonium occurs as part of a radioactive process called nuclear fission. It involves atomic chain reactions and the release of atomic energy. The recipe for creating plutonium is not to be triedin a kitchen or even in an ordinary lab.
In the 1940s, scientists began to realize the useful possibilities of the immense energy in radioactive materials. Almost at once they realized that the earth's stores of uranium and other natural radioactive substances was limited, and they set about finding recipes to create man made supplies. The basic ingredient for the job was natural uranium ore. Every element, of course, has several isotopes or forms with different numbers of neutrons in their atomic nuclei. The isotope uranium 238 is the one used to create the atomic element named plutonium.
This man made element is created in a nuclear reactor. The uranium 235 isotope must be present as well as the uranium 238. As the uranium 235 atoms undergo nuclear fission they give off neutrons, and the uranium 238 atoms. An extra neutron added to a nucleus creates a heavier isotope and uranium 238 becomes uranium 239 but not for long. The extra neutron upsets the structure of the atom. Its nucleus bursts, emitting one electron and a quota of nuclear energy.
The nature of any atom depends upon the number of positive protons in its nucleus. Electrons carry equal and opposite negative charges and neutrons are electrically neutral. When a neutron sheds an electron, it loses one negative charge. What re¬mains is a positively charged proton. When the nucleus of the unstable uranium 239 atom shatters, it loses an electron and gains an extra proton. Atomic numbers are the numbers of protons in the nucleus. The element uranium 92 is hence changed to element 93. This new man made element is neptunium.
Neptunium is a very unstable radioactive element. In 2 1/2 days, half its atoms shatter asunder. Each shattered nucleus loses another electron, changing a second neutron into a positive proton. This atom is element 94 plutonium. In 1941, the first successful experiment created one ten millionth part of an ounce of plutonium. Nowadays we create pounds of the silvery white metal every day. Our man made plutonium is stockpiled for use as a fuel in nuclear reactors and also for use in nuclear explo¬sions.
Uranium was discovered in 1789 and named for planet Uranus. Its two synthetic children were created in 1940. Neptunium was named for the planet Neptune and plutonium for the planet Pluto. Since then, nine isotopes of plutonium have been created. The best is plutonium 239. This radioactive substance has a half life of 24,000 years which means that half the supply decays in 24,000 years, half the remaining supply decays in the next 24,000 years and so on.