Classification of concretes for neutron shielding with respect to atomic composition

In the design calculations for the shielding of intensive neutron sources, assumptions on the atomic composition of the planned concrete must be made. The atomic compositions given in this standard are to standardize these assumptions insofar as differences between the results of various calculations should no longer depend on random assumptions as to the concrete composition. The given guide values enable calculations which in general are less inaccurate as a result of deviating atomic composition in the raw materials than the deviations of the concrete raw density due to manufacture, and of the water and iron content. For the shielding calculations, practically only the mass coverage per unit area is of importance. The guide values of this standard are in the rule to be used for the water and iron content to simplify the comparison of different calculations. (orig./LH)