Transuranic Element Production
HOW TRANSURANIC ELEMEMTS ARE PRODUCED IN NUCLEAR REACTORS?
Uranium is the largest/heaviest atom that occurs naturally. It has the most
protons. A transuranic element has more protons than uranium. In a nuclear
reactor that produces "transuranic" elements, neutrons are collided with the
uranium. These neutrons will sometimes stick to the uranium, making it a
heavier version of uranium. Because the heavier uranium has too many
neutrons, a neutron experiences "beta decay". It turns into a proton and an
electron, making the atom transuranic. Plutonium is such an element.
Nuclear reactors produce lots of neutrons from fission reactions. Some of
these neutrons are captured by heavy nuclei, such as uranium-238. This
makes a new nucleus with the same atomic number but a higher atomic mass.
Some of these new heavier nuclei can then convert to nuclei of other
elements by beta decay, in which one neutron converts to a proton, an
electron (beta particle), and an electron anti-neutrino (usually
undetectable). So the mass of the nucleus stays about the same, but the
number of neutrons goes down by one and the number of protons goes up by
one. Plutonium-239, for instance, is produced by on electron capture by
uranium-238 followed by two beta decays:
U-238 + n --> U-239 --> Np-239 + beta --> Pu-239 + beta
Richard E. Barrans Jr., Ph.D.
PG Research Foundation, Darien, Illinois
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Update: June 2012