Device for retaining a hot melt in particular a core melt-through inside the spreading chamber of a nuclear reactor installation

A water-cooled nuclear reactor installation, comprising:

• a pressure vessel;
• a space below said pressure vessel for receiving a core melt in the case of a core meltdown, said space below said pressure vessel having a given area;
• a spreading chamber disposed laterally offset from said space below said pressure vessel and lower than said space below said pressure vessel for receiving the core melt;
• an obliquely inclined conduit connecting said space below said pressure vessel with said spreading chamber;
• said spreading chamber having a spreading area larger than said given area of said space below said pressure vessel for spreading the core melt over said spreading area and for cooling the core melt;
• and
• said spreading chamber including a bearing and containment structure, a protective layer disposed upwardly adjacent on and protecting said bearing and containment structure of said spreading chamber, an outer sacrificial layer disposed upwardly adjacent on said protective layer, said outer sacrificial layer being melted when in contact with the core melt and cooling the core melt, and a cooling system for a delayed supplying of a coolant, said cooling system having temperature-dependently opening feed channels integrated in said sacrificial layer, for supplying the coolant to the core melt when said temperature-dependently opening feed channels get in contact with the core melt.