Physically consistent neutron importance cross section energy averaging

The paper proposes a physically consistent technique to obtain average broad energy group cross sections from fine group data, in place of currently used neutron spectra averaging. The method is based upon the principle that in energy averaging procedures the 'total importance content' has to be preserved and it can be inserted within the framework of the so-called 'bilinear weighting' procedures, that have already been introduced and used in neutronic calculations. (author)