Abstract: Under severe accident conditions, the integrity of containment is threaten by hydrogen deflagration or detonation, and measures must be implemented to mitigate or eliminate the hydrogen risk. For the specific 600 MWe nuclear power plant with large-dry containment, the small-break loss-of-coolant-accident (SB-LOCA) was calculated, and the removal effects of passive autocatalytic recombiners and their impacts on the containment pressure and temperature were analyzed. The results show that catalytic recombination can remove hydrogen in containment continually and steadily, however, its capability is somewhat limited for large quick hydrogen release.