I will present the result of a numerical study coupling the 2D PIC code CALDER to the 3D nuclear physics code FLUKA in order to model ion and neutron generation which we could expect at both 1 PW and 10 PW levels of irradiation on thin solid (CH) targets. The neutron are modelled in the simulation chain, using as input the protons simulated by the PIC code, and produced through a spallation process in a Pb target. The simulated values give support to the possibility to endeavour r-process nucleosynthesis investigations using these upcoming lasers.