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

Abstract: A reactor core isolation cooling system includes a reactor pressure vessel containing a reactor core, a drywell vessel, a containment vessel, and an isolation pool containing an isolation condenser. A turbine is operatively joined to the pressure vessel outlet steamline and powers a pump operatively joined to the pressure vessel feedwater line. In operation, steam from the pressure vessel powers the turbine which in turn powers the pump to pump makeup water from a pool to the feedwater line into the pressure vessel for maintaining water level over the reactor core. Steam discharged from the turbine is channeled to the isolation condenser and is condensed therein. The resulting heat is discharged into the isolation pool and vented to the atmosphere outside the containment vessel for removing heat therefrom.

Abstract: A nuclear reactor system which includes a containment uses, upon loss-of-coolant event, an isolation condenser submerged in a large supply of water and elevated some distance above the system pressure vessel to effect both initial and decay heat dissipation cooling in the containment. The isolation condenser has inlet thereto communicated to an open entry conduit disposed in the containment so that steam and heated gasses in the containment space enter the isolation condenser and are cooled. Condensate resulting from the cooling is returned to an elevated system gravity coolant supply pool, which pool is used for replenishing coolant lost from the pressure vessel, the return being through a return conduit that has a lower end section configured with a water trap with non-condensable gasses present in the steam being separated from the condensate and vented to the suppression pool.