Favoured transmutations

MA isotopes can be transmuted more efficiently in fast reactors than thermal because most have a lower ratio of capture to fission for fast neutrons. However, for the efficient transmutation of fission product isotopes a soft spectrum is required, so moderating assemblies situated around the core of a fast reactor are favoured. 

In addition, Fludd presented the creation in terms of two sets of experimental analogies. One comprised simple physical illustrations of the separation of the elements by boiling water to steam or by observing layers of liquids of different densities in a vessel such analogies had been well known since early times and had been common in the writings of the Church Fathers. The other depicted creation in terms of alchemical transmutation. This was favoured by many Paracelsian chemists, but few if any took it as far as Fludd did. He mentioned this in De macrocosmi historia and developed it more fully in his Philosophicall Key. As we have already seen, he identified the chaos of creation with the alchemical stage of blackness or nigredo, because both contained the elements in confusion ... 

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