Abstract: A nuclear reactor, in particular a pressurized water reactor, has a containment, a containment shell surrounding the containment and a concrete construction of a reactor building surrounding the containment shell. A heat dissipation system for the nuclear reactor includes a sump volume disposed in a lower region of the containment shell for receiving coolant. A sump cooler is disposed inside the sump volume, has cooling tubes with a primary side and a secondary side and has feed and return lines. The primary side of the cooling tubes is covered at least when the sump volume is largely filled with coolant. An intermediate cooler has a tertiary side and is connected through the feed and return lines of the sump cooler to the secondary side of the cooling tubes. A heat sink is disposed outside the reactor building and is connected to the intermediate cooler on the tertiary side.

Abstract: A pressurized water reactor residual heat extraction system uses the secondary cooling circuit to extract the residual heat in certain operating and malfunction conditions. A steam generator (D1) has a connection, located on the live-steam and feed-water side, to the secondary circuit side of a safety condenser (SK1). The tertiary circuit side of the safety condenser is fed from a water reservoir (B) located at a physically higher level. The steam generated is vented to the atmosphere through a blow-off line (b2) which may include a separator. A make-up feed device (E1) is connected to the secondary side of the steam generator. Because of the higher location of the safety condenser with respect to the steam generator, the heat energy in the secondary cooling circuit circulates by natural circulation.

Abstract: A secondary-side residual-heat removal system for a pressurized-water reactor removes residual heat through a secondary side of a steam generator in certain modes of operation and malfunction. For this purpose, the respective steam generator has a connection on a live-steam and feed-water side to a secondary side of a safety condenser. The connection on the feed-water side is led to a supply connection of a swirl or vortex chamber valve having a control connection which is connected to a feed-water line part on the pressure side, with a downgradient from a main feed-water pump, and the swirl or vortex chamber valve has an outlet which opens out into a feed-water inflow space of the steam generator. A tertiary side of the safety condenser is fed from a water reservoir disposed at a geodetically higher level. The steam being generated is discharged into the atmosphere through a blowing-off line, with a separating device if appropriate.