Abstract: A retaining device has a multi-layer protective cladding for protecting the bearing and containment structure of a spreading chamber for the controlled spread and cooling of a melt from a nuclear reactor pressure vessel. The spreading chamber is configured under the spreading concept, i.e. the melt spreads and cools therein. The protective cladding has at least two layers: an outer sacrificial layer acts as a thermal shock barrier and melting substance; a protective and insulating layer, disposed inside the sacrificial layer and protecting the underlying bearing and containment structure, acts as thermal protection layer and retaining layer for the hot melt. The protective and insulating layer includes a first partial layer of fireproof concrete adjacent the bearing and containment structure, and a second partial layer of temperature-resistant ceramic blocks, in particular ZrO2 adjacent the sacrificial layer.

Abstract: A nuclear reactor includes a core melt collection chamber having walls with multilevel protective layers. The layers include one layer part made of refractory concrete and another layer part made of ceramic bricks. The protective layers are anchored to the structural concrete of the collection chamber. In order to provide structural simplification, the layer part made of refractory concrete is constructed in the form of prefabricated blocks which are jointed together and are fastened to the structural concrete, and the layer part made of ceramic bricks is braced to the blocks of the layer part made of refractory concrete.

Abstract: A nuclear power plant has a reactor core and a containment chamber for receiving core melt of the reactor core. A cooling system for cooling the containment chamber includes a flooding container to be filled with coolant fluid. A cooling pipe leads from the flooding container to the containment chamber. A passively opening closure element closes the cooling pipe in the flooding container and opens as a function of a level of the coolant fluid.

Abstract: A device for collecting reactor-meltdown products from a reactor pressure vessel includes an antechamber disposed below the reactor pressure vessel, an expansion chamber having a floor forming an expansion surface for reactor-meltdown products, and a bulkhead being disposed between the antechamber and the expansion chamber and being destructible by the reactor-meltdown products. The bulkhead has a plurality of parts including at least one part being thermally destructible by the reactor-meltdown products. The at least one part is joined to the other parts for clearing a flow path for the reactor-meltdown products from the antechamber into the expansion chamber upon a destruction of the at least one part.

Abstract: A nuclear reactor facility has a collecting chamber for a core melt, a coolant tank and a coolant connecting line having an inlet end connected to the coolant tank and an outlet end protruding into the collecting chamber and having an outlet cross section. A closing device at the connecting line which opens as a function of temperature for initiating cooling of the core melt includes a closing member disposed at the outlet end of the connecting line for normally tightly closing the outlet end. The closing member has a temperature-dependent opening element for tripping clearance of at least a portion of the outlet cross section of the connecting line upon thermal action by the core melt to direct the coolant from the coolant tank, through the connecting line and into the collecting chamber. The opening element being a plastic block which thermally insulates the coolant, and is corrosion-resistant.

Abstract: A nuclear reactor has a core and a pressure vessel with a wall and an interior. A pressure relief responding as a function of temperature is provided in the case of insufficient core cooling (due to a highly improbable failure of the cooling devices and emergency cooling devices). A safety device protecting against overpressure failure of the pressure vessel upon insufficient cooling of the core includes a pressure pipe passing pressure-tightly through the wall and extending into the interior of the pressure vessel. The pressure pipe has at least one pressure compensation opening formed therein in the interior of the pressure vessel and has a fusible sealing body sealing the pressure compensation opening. The fusible sealing body is formed of a melting solder melting at a limit temperature, such as 600.degree. to 700.degree. C., and unblocking the pressure compensation opening, but keeping the pressure compensation opening sealed during normal operation.

Abstract: A nuclear reactor has a pressure vessel with an interior, a coolant conducting surface, such as a wall of the pressure vessel or a line passing through the wall of the pressure vessel, a pressure relief line, and a core. A safety device which protects the pressure vessel against overpressure failure upon inadequate cooling of the core includes a pressure relief valve being pressure-tightly inserted into the coolant conducting surface and having a seat, a closure element normally disposed on the seat for blocking a flow from the interior of the pressure vessel to the pressure relief line, an abutment, and a valve closing spring holding the closure element and being supported against the abutment. A force transmission element holds the abutment and has an end facing away from the abutment. A detent is disposed in the pressure vessel and fixes the end of the force transmission element. The detent is releasable in dependence on a given threshold temperature, for example 700.degree. C.