Accuracy of the reactor core simulations for determination of the antineutrino spectrum for the solid experiment at the BR2 reactor

Discrepancies observed between measured data and theoretical predictions of reactor antineutrino experiments at short distances are known as the Reactor Antineutrino Anomaly (RAA). RAA require an accurate assessment of the flux and energy spectrum of electron antineutrinos taking into account the various sources of systematic errors due to theoretical and experimental uncertainties. The strategy of the SoLid collaboration is to use state-of-theart methods to predict the antineutrino flux and energy spectrum, based on a detailed 3D model of the BR2 core for the MCNP6 (CINDER'90) code. In this paper, we discuss the various assumptions and approximations adopted in the BR2 reactor core model and their effect on the calculated fission rates and antineutrino spectrum.