CFD and LP code benchmark evaluating the onset of par operation in case of extremely low oxygen concentration

•Passive Autocatalytic recombiner was investigated in the THAI containment test facility within the OECD/NEA THAI-2 Joint Project.•Investigations focused on late phase severe accidents including oxygen starvation.•Hdrogen mitigation by PAR was demonstrated under realistic boundary conditions.•An international code benchmark was performed with code applications using CFD and Lumped Parameter models with detailed chemistry and correlations for the prediction of the passive autocatalytic recombiners.