Abstract
With the availability of high-statistics and high-resolution anti-neutrino energy spectra, measured in experiments dedicated to the study of the neutrino oscillation in proximity of a nuclear reactor, we can now envisage to use these data as integral measurements to constrain fission and beta-decay models and nuclear data libraries. In this paper we present the ingredients for the simulation of an anti-neutrino energy spectrum and their sensitivity to the constraint by measured energy spectrum.