An Analytic Representation of Fast-Reactor Neutron-Energy Spectra

It is suggested that fast-neutron spectra can be represented by the expression The parameters of this representation can be determined from experimental results, such as activation integrals, or from calculated group fluxes, by the least-squares method. A practical procedure to derive the parameters from results of multigroup calculations is given, and possible applications of smoothing the stepping spectra are discussed. The method was successfully applied to various spherical metallic critical systems. Some examples are given, and the quality of the resulting spectra is discussed.