The deactivation process of Ni/MgAlOx spinel during ATR of model biogas is assessed. A methane combustion zone creates a hot spot and leads to NiO formation. NiO reacts with the support at high temperature forming inactive NiAl2O4 spinel. The Mg/Al ratio in the support strongly affects the Ni deactivation rate. A dual catalytic bed prevents Ni oxidation and deactivation.