Nuclear radiation characteristics, table

Much of the basic chemistry of thorium and uranium tvas known in 1942, but the nuclear decay characteristics of most of the (FPs) were not. Furthermore, the chemistry of many of the FPs and transuranic (TRU) elements was not known in sufficient detail. Promethium, technetium, and all the TRU elements were new to science and much had to be inferred from an element s position in the periodic table. The chemical and physical effects of radiation imposed additional difficulties and imcerlainties in the proposed processes, as they do even today. 

Half-lives as short as millionths of a second and as long as billions of years are known. The half-lives of some radioisotopes are listed in TABLE 21.5. One important feature of half-Uves for nuclear decay is that they are unaffected by external conditions such as temperature, pressure, or state of chemical combination. Unlike toxic chemicals, therefore, radioactive atoms cannot be rendered harmless by chemical reaction or by any other practical treatment. At this point, we can do nothing but allow these nuclei to lose radioactivity at their characteristic rates. In the meantime, we must take precautions to prevent radioisotopes, such as those produced in nuclear power plants (Section 21.7), from entering the environment because of the damage radiation can cause. 

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