Synthesis of fast reactor space-energy neutron fluxes

Spectral synthesis methods, in which the space-energy flux is synthesized from known flux spectra, are applied to one-dimensional, fast reactor static problems. The methods include few-group synthesis models that employ either the same trial spectra in all regions of the reactor model or different trial spectra in different spatial regions.Numerical results demonstrate that the space-energy flux can be adequately represented by these few-group synthesis models; moreover, the spatially dependent spectra agree very well with similar, "exact" flux spectra calculated by direct multigroup methods.Region-integrated reaction rates calculated with the synthesized flux spectra are in good agreement with those calculated with the flux spectra derived from direct methods.