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.