Abstract: In a reactor pressure vessel for a boiling-water reactor having a feedwater inlet nozzle, the combination includes a heat protective pipe received in the nozzle and having an extension projecting therefrom, a feedwater sparger ring disposed in a given plane, and means for connecting the feedwater sparger ring to the heat protective pipe, the connecting means includes an elbow extending angularly from the given plane and connecting the feedwater sparger ring to the extension of the heat protective pipe.

Abstract: An improved pressurized water-cooled reactor system which includes a reactor core pressure vessel; coolant lines coupled to the pressure vessel; vertically arranged steam generators having the housings thereof coupled to the coolant lines; and coolant pumps associated with the steam generators and coupled to the coolant lines. Each of the pumps has a vertically arranged impeller portion driven by an electric motor for circulating coolant between the pressure vessel and tube sheet type heat exchangers in the steam generators, at least the impeller portion of each pump being disposed within a chamber associated with each steam generator which is communicative with the coolant lines. The vessel, the coolant lines and the steam generators including the impeller chamber are each individually encapsulated by rupture-proof safety housings (encasements) forming a protection system for the primary loop components.

Abstract: A nuclear reactor installation includes a pressurized-water reactor pressure vessel positioned in a reinforced-concrete structure forming a wall surrounding the pressure vessel and forming an annular space around the pressure vessel, this space containing a layer of discrete elements such as gravel, ceramic bodies, steel balls, etc. This layer directly contacts the concrete wall, possibly through a steel sheet or plate skin and between it and the pressure vessel, a thermally-insulating and pressure-resistant encasement is built from separable segments cast from suitable concrete, a steel sheet or plate skin preferably being interposed between the layer of discrete elements and this encasement, the discrete elements being compacted so that radial force transmitted from the pressure vessel via the encasement is transmitted through the discrete elements to the concrete wall formed by the reinforced-concrete structure.

Abstract: A reactor pressure vessel is supported at its bottom end by an inverted frusto-conical surface concentric with the axis of the vessel and fixed to its bottom, this surface slidably resting on an upright frusto-conical surface which is also concentric with the vessel's axis. Radial thermal movements of the reactor's bottom results in diameter changes in the conical surface fixed to its bottom so that this surface by cam action moves up and down on the other surface, and with a properly defined angularity, compensates for the vertical thermal expansion of the vessel which occurs simultaneously with its radial expansion.

Abstract: A nuclear power plant installation includes a concrete biological shield forming a pit in which a reactor pressure vessel is positioned. A steam generator on the outside of the shield is connected with the pressure vessel via coolant pipe lines which extend through the shield, the coolant circulation being provided by a coolant pump which is also on the outside of the shield. To protect these components on the outside of the shield and which are of mainly or substantially cylindrical shape, semicylindrical concrete segments are interfitted around them to form complete outer cylinders which are retained against outward separation radially from the components, by rings of high tensile steel which may be interspaced so closely that they provide, in effect, an outer steel cylinder. The invention is particularly applicable to pressurized-water coolant reactor installations.