Passive containment cooling system for a nuclear reactor

A passive containment cooling system 14 includes a containment vessel 24 surrounding a reactor pressure vessel 16 and defining a drywell 26 therein containing a non-condensable gas. An enclosed wetwell pool 28 is disposed inside the containment vessel 24, and a gravity driven cooling system (GDCS) pool 44 is disposed above the wetwell pool 28 in the containment vessel 24 and is vented to the drywell 26. An isolation pool 52 is disposed above the GDCS pool 44 and includes an isolation condenser 54 therein. The condenser 54 has an inlet line 60 disposed in flow communication with the drywell 26 for receiving the non-condensable gas along with any steam released therein following a loss-of-coolant accident (LOCA). The condenser 54 also has an outlet line 62 disposed in flow communication with the drywell 26 for returning to the drvwell 26 both liquid condensate produced upon cooling of the steam and the non-condensable gas for reducing pressure within the containment vessel following the LOCA.