MadSci Network: Physics |
Kenneth: The quick answer to your question is yes! The how to do it is a bit more complicated. The only way to have a radioactive atom decay in a shorter period of time is to change its half life. That is the length of time it takes for 1/2 of a group of atoms of one radioactive isotope to decay. A radioisotope is a radioactive isotope of a given element--all radioisotopes of a given element have the same number of protons, so that they are all the same element, but different numbers of neutrons. The word isotope means "same place"; the same atomic number (number of protons). That reduces the amount left by 1/2. The hitch is that the half life is a characteristic property of every different radionuclide (a radionuclide is any radioactive nucleus). Since it is a nuclear property, it basically cannot be changed by chemical reactions. An example is Sodium-24 which has a half life of about 15 hours. It has the same half life as sodium metal, sodium chloride, or any other chemical form it is in. The same is true for Uranium, Plutonium, and all other radioactive materials commonly encountered as wastes or fission products. In order to change the half life and make the material decay faster, we have to change the structure of the nucleus. This can be done by placing the material in a nuclear reactor and exposing it to neutrons. Or, it could be done by placing the material in the beam of a particle accelerator and using protons, deuterons, or helium nuclei as the bombarding particles. In almost all cases, the addition of a neutron or charged particle to the original nucleus changes it to one with a shorter half life. These are not inexpensive alternatives, although for small quantities of extremely long lived transuranic materials, the process may prove to be feasible. At least several groups are looking at the process. One physical fact to be aware of is that at the numbers of neutrons available in a reactor, it takes a long time to react with all the atoms to be changed. The probability that an atom undergoes transformation is on the order of 1E-10 per second in a research reactor with a very high number of neutrons available per second (around 1E14 which is attained at only a few research reactors in the world). The equations for conversion in a reactor or accelerator are given in Nuclear and Radiochemistry, 3rd Edition Friedlander, Kennedy, Macias, and Miller Wiley-Interscience, 1981 (but the equations are still valid today) or Radiochemistry and Nuclear Methods of Analysis Ehmann and Vance Wiley-Interscience, 1991
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