Nuclear power plant and passive accident ventilation system thereof

The invention relates to a nuclear power plant room and a passive accident ventilation system thereof. The passive accident ventilation system comprises an air outlet part, a filter assembly, a heat exchange assembly, a chimney, a room and a gas pipeline. Waste gas exhausted from the air outlet part in the nuclear power plant control area room sequentially passes through the filter assembly, the heat exchanger and the chimney and is finally exhausted from the top end opening of the chimney, according to the chimney effect, the gas density at the bottom of the chimney is low, the density difference is generated between the gas density and air at the top of the chimney, sufficient pressure is generated, and negative pressure in the nuclear power plant control area room is maintained. Therefore, the gas entering the bottom of the chimney is continuously pressed to the top opening of the chimney along the interior of the chimney by the air pressure and is discharged, a continuous passive exhaust filtering functio