Isolation condenser passive cooling of a nuclear reactor containment

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. The condensate flow to the gravity pool thus supplements this stock as a core cooling source and continues to do so after the original gravity supply pool stock is exhausted, the condenser function and condensate effusion therefrom continuing during cooldown and decay heat removal, the effusion flow of condensate entering the empty gravity pool chamber as discharge from the water trap end of the return conduit and gravity feeding as an outflow therefrom into the pressure vessel through the gravity pool piping connection with the vessel.