The study of Ultra-High Energy Cosmic Rays (UHECRs) via the multi-messenger approach is reaching a level that requires going beyond steady-state sources. Meeting this challenge requires improvements of the existing tools and defining new methods to accelerate the computations related to the propagation of UHECRs in extragalactic space and within the sources.With this aim, the inclusion of hadronic interactions in the widely used code CRPropa has been completed allowing in-source propagation of UHECRs with all relevant interactions: magnetic, photonuclear and hadronic.
This contribution presents the implementation of hadronic interactions in CRPropa by exposing hadronic modelling softwares (e.g. EPOS-LHC, SYBILL, QGSJet) with the help of the code ''chromo''. The impact on the performance of CRPropa is reported and compared to other methods used to simulate hadronic interactions. The physical interplay of hadronic and photohadronic interactions is discussed in the context of plausible scenarios of bursting sources.
