85° Question 18 The contamination threat would vanish if man figured out how to turn off radiation--how to make an unstable atom stable again. Who is presently sponsoring research into this matter? What are the prospects? Answer 18 | Response to this question requires a brief review of radioactive decay. Whenéver a new radionuclide is identified, two properties always investigated by scientists are the method by which the radionuclide disintegrates, or decays, and the rate. For every radionuclide yet found (over two hundred) the method is found to be constant and for any selected increment of time, the fraction of atoms present at the start of the increment which decays during the increment is also constant. (This constant decay fraction is arithmetically related to the physical half-life). In otherwords, the constant nature of decay method and decay half-life are ‘werified by such e body of evidence that we consider them to be natural laws. If we are asked to "turn off" radiation we must; in effect, either find that we are mistaken in our understanding of these natural laws, or else find exemption from them. Of course, it was not very long ago that scientists were taught, as a natural law, that matter is indestructible. ‘Hence, it would be unwise to make a categorical statement that no such exemption could ever be found. However, the prospects are not bright for practical application of such an exemption even if the theory were to be developed by continuing basic nuclear physics-research. It seems reasonable to assume that a fundamental property of a nucleus (the decay constant) can only be changed, if at all, by some kind of bombardment of the nucleus. |