Abstract: The nuclear boiler comprises at least one heat exchanger located externally of the reactor vessel in order to effect heat exchange between the liquid metal coolant in the form of liquid and water to be vaporized and superheated together with a main storage tank connected to the reactor vessel for receiving liquid metal and inert gas. A main storage tank pipe system fitted with valves consists of a first overflow pipe for connecting the top of the reactor vessel to the bottom of the storage tank, and at least one second pressure-equalizing pipe between the top of the reactor vessel and the top of the storage tank. Controlled-atmosphere compartments forming the reactor containment structure and containing the unclear steam supply systems provide biological protection for operating personnel and guard against impacts of external origin.

Abstract: A liquid metal reactor comprising a vessel containing the core and liquid metal, at least one heat exchanger ensuring a heat-exchange between said liquid metal and a second fluid, a first duct connecting said vessel with the inlet of said exchanger and a second duct connecting said vessel with the outlet of said exchanger. Means are provided for restricting the movement of said exchanger in two directions perpendicular to the direction of said first duct.

Abstract: Exchanger which incorporates a casing in which the heat carried by a primary fluid is transferred to a secondary fluid so as to heat the latter, the secondary fluid circulating in the tubes, whose opposite ends issue into tubular supply and discharge mains located externally of the exchanger casing and surrounding the latter at least partly, wherein each of the tubes comprises two access devices each sealed by a removable plug, while each of the access devices is located in a part of the tube positioned between the exchanger casing and the corresponding main.The present exchanger is intended more particularly for the transfer of heat between two circuits of a nuclear power station.

Abstract: The heat exchanger comprises a vertical outer cylindrical shell of substantial length, a distributor for supplying the internal space of the shell with liquid sodium, at least one tube bundle placed within the shell for circulating water in heat-exchange relation with the sodium and means for maintaining an inert gas atmosphere above a predetermined free level of liquid sodium. The top and bottom tube ends are fitted with thermal sleeves for joining them to the lateral wall of the shell and passing them through this latter. The distributor is placed within the shell above the tube bundle between the top end of said bundle and the free level of liquid sodium.

Abstract: A liquid metal cooled nuclear reactor comprising a core, a main vessel comprising a first supporting means, a primary vessel mounted inside said main vessel and coaxial therewith, at least one exchanger outside said vessels. Said primary vessel comprises a core-diagrid and a second supporting means integral with the main vessel lateral wall and with the primary vessel lateral wall. These lateral walls define an annular space in which is formed a horizontal partition.

Abstract: The steam generator shell contains a bundle of straight tubes, the upper portion of which constitutes the superheat zone. A cylindrical jacket surrounds the upper portion of the shell and defines an annular reheat space containing helical tubes connected to a bottom steam inlet header and to a top outlet header. The reheat space communicates with the interior of the shell through a lower set of windows and through an upper set of windows provided with a cylindrical valve for regulating the rate of flow.

Abstract: A pump/heat exchanger assembly has tubes with double walls, inner and outer respectively, the outer wall being provided with inner longitudinal grooves. The exchange occurs between a primary fluid circulating outside the said tubes and a secondary fluid circulating inside the said tubes. A plurality of the double-walled tubes are arranged in an annular space, each tube consisting of a plurality of interconnected tube sections, having horizontal curved portions and elbowed portions, the tube sections being joined together at the elbowed portions. At least one leakproof annular chamber is provided outside the annular space and connected thereto. Leaks in the said tubes, are detected by injecting an inert gas, under a given pressure, into the said annular chambers, and comparing the pressure of the gas in the chamber with a maximum and a minimum pressure.

Abstract: A secondary heat transfer circuit for a nuclear reactor comprises a steam generator module, an intermediate heat exchanger, and a pump which circulates a heat transfer liquid, e.g. liquid sodium, between the heat exchanger and the steam generator module. The steam generator module includes a central return duct for cold heat transfer liquid and the pump intake is directly connected to the central duct. In a modification, a plurality of steam generator modules are connected to a single duct.