Abstract: The reactor comprises a vessel (3) containing the core of the reactor (4) and arranged with its axis vertical in a vessel well (2). The cooling and protection device (11) rests on the bottom of the vessel well. It consists of a metal floor (11) which covers the bottom of the vessel well (5) and in which are made channels (20) for cooling by circulation of a cooling fluid. The cooling fluid supply is connected to the cooling channels (20).

Abstract: The device is constituted by a metal structure (10) resting on the bottom of the reactor pit (3) and submerged in a mass of water filling the lower portion of the reactor pit (3). The metal structure (10) comprises a central chimney (11), a recovery wall (12) constituted by juxtaposed dihedra (22) made from metal sheet, and a peripheral wall (13) fixed to the external edges of the dihedra (22) and providing water passages at the periphery of the reactor pit. When the molten core of the reactor spreads into the reactor pit, following an accident, the structure (10) ensures its recovery and prevents contact between the molten core and the bottom of the reactor pit. The molten core flows onto the wall (12) in such a manner as to constitute a layer of small thickness which is cooled over its upper surface and over its lower surface and which solidifies rapidly.

Abstract: The device for pressure-sealed obturation comprises a flexible tubular casing (22) having an open end along the perimeter of which the casing constitutes an inflatable toric seal (30) and a base (22a) in the form of a glove finger on which there is fixed the end of a shaft (21) disposed at the central part of the casing (22). The shaft (21) passes through the base (22a) of the casing (22) in a sealed manner. The device also comprises a plate (38) for retaining the casing (22) comprising at least two parts articulated to one another as well as retention plate (41) for fixing the retaining plate (38) under the base (22a). Ring shaped elements (43) are retained against the toric seal (30) by an articulated spacing device (47).

Abstract: The apparatus comprises wedging members (12, 13) consisting of elastic metal strips folded into crenellations, and a wedging member cooperating with said members and consisting of a flat strip (14) provided with openings (20) having the same spacing as the crenellations of the wedging members (12, 13). The wedging members (12, 13) have outer support surfaces (16) and inner support surfaces (17) cooperating with the flat strip (14). In the unlocked position of the apparatus the surfaces (17) coincide with the openings (20). In the locked position the members (12, 13) are moved apart by the flat strip (14), which comes into contact with the support surfaces (17). Passage from one position to the other is achieved by longitudinal displacement of the flat strip (14). The apparatus can be used in particular as an antivibratory bar in a steam generator of a pressurized water nuclear reactor.

Abstract: Device for purifying liquid metal coolant for a fast neutron nuclear reactor, comprising a pump (6) for circulating the liquid metal, the metal then being purified and heated after purification, as well as a filter (24) of metallic fibers. It consists of an assembly of annular chambers with a vertical axis, closed at their lower part by a base plate (10) and defined and separated from each other by an assembly of coaxial cylindrical metallic shells. The device comprises, from the exterior inwards, a degassing chamber (12), a chamber enclosing an economizer-exchanger (14, 16), a thermal insulation wall (18), a cooling chamber (20) and a purifying chamber (22) in the central part of which is a filter cartridge (24). In the central part of the cartridge (24) is a channel (25) for collecting the purified liquid metal in communication with a basin (44) for collecting the purified liquid metal rising above the device.

Abstract: Cover-plug for the core of a fast neutron nuclear reactor, comprising a support-plate (6), a cylindrical shell (8) having a vertical axis fixed integrally to the support plate (6) and braces (14) which are transverse relative to the shell (8). Vertical tubes fixed to the support plate (6) at their upper part are joined to the braces (14), which consist of at least two conical webs (14) having their axes coincident with the axis of the shell (8). These conical webs have a top angle greater than 120.degree. and a diameter which is slightly smaller than the diameter of the shell (8), at their base. The brace (14a) situated in the lowest position in the shell (8) ensures the deflection of the reactor cooling fluid. The invention applies, in particular, to fast neutron nuclear reactors of the integrated type.

Abstract: Slab for closing a fast neutron nuclear reactor, comprising a first central annular part (10) the diameter of which is substantially equal to the diameter of the reactor vessel (5) and a second peripheral annular part (11) connected to the first part (10) by its outer shell (14). Both parts of the slab are made in the form of steel caissons enclosing concrete. The central part (10) is strengthened by two frusto-conical shells (20, 21). The peripheral part (11) is strengthened by flat axial webs. The inner shell coincides with the outer shell (14) of the central part. The invention applies in particular to fast neutron nuclear reactors cooled with liquid sodium, of an integrated type.

Abstract: Device for producing steam by heat exchange between a heat-transfer liquid metal and feed water, comprising a cylindrical casing (31) receiving liquid metal in its upper part through at least one nozzle (35, 36). The liquid metal enters in a space bounded by a central sleeve (38), a lower perforated distribution plate (40) and a first perforated plate (45). A second perforated plate (46) parallel to the latter is separated therefrom by perforated crosspieces (47). The perforated plates (45 and 46) are disposed between the sleeve (38) and a peripheral sleeve (39). The three plates (40, 45 and 46) have identical perforations which are aligned in the vertical direction. The distribution plate (40) is provided with stiffening ribs (44) ensuring the distribution of the liquid metal thereon. The invention applies, in particular, to fast breeder nuclear reactor steam generators cooled by liquid sodium.

Abstract: Annular slab for closing the vessel of a fast nuclear reactor, comprising at least one downwardly divergent frusto-conical sleeve coaxial with the inner and outer sleeves delimiting the slab, dividing the slab envelope into upper and lower parts respectively filled with concrete incorporating metal reinforcements and with concrete for radiation protection.

Abstract: The invention relates to an emergency shut-off device, in the case of leakage, of a tube of a steam generator where the heat of vaporization is contributed by a liquid metal circulating in contact with the outer surface of the tube. The device includes on the terminal portion of the tube connected to the water supply device a tubular bush interposed in the path of the feed water. The bush contains a valve connected to the bush by a rupture part. The breakage of the part under the effect of an increased flow of water, in the case of a leakage, enables the closing of the outlet of the bush. The device includes also, in the terminal portion of the tube connected to the steam collector a bush containing a free valve enabling the steam outlet to be closed in the case of a leakage in the tube. The invention is applied in particular to steam generators of fast breeder nuclear reactors cooled by liquid sodium.

Abstract: A liquid absorbent safety rod for a nuclear reactor comprising a reservoir, the upper compartment of which is filled with liquid absorbent under gas pressure communicates with a lower compartment situated in the core of the reactor the lower compartment being filled with gas under pressure by way of a disconnectable hollow rod. By varying the gas pressure in the lower compartment, the quantity of absorbent descending into this compartment may be varied. When the hollow rod is disconnected from the reservoir, all the liquid absorbent falls into the lower compartment.

Abstract: Improvement to a safety device with a solid absorbant which may be used in a water-cooled reactor, essentially constituted by a cylindrical tank placed above the core of the reactor and containing a gas kept under pressure as well as an absorbant in a divided form. The opening device of the tank is sensitive to a depressurization. The tank supplies simultaneously several spouts each leading to a tube implanted in the core of the reactor.This is a continuation, of application Ser. No. 416,140, filed Nov. 15, 1973, now abandoned.

Abstract: Solid absorbent in particle form stored in an intermediate chamber at a position above the reactor core within a safety device container under fluid pressure is driven by the escape of the pressure fluid along a series path from the upper compartment to the lower compartment, into the lower compartment to shut down the reactor when a destructible seal within a pipe carried in the lower compartment ruptures in response to reactor malfunction.

Abstract: A liquid absorbent safety device for a nuclear reactor, constituted by a cylindrical tank comprising two communicating superposed compartments. The upper compartment situated above the reactor is filled with liquid absorbent surmounted by a gas under pressure. The lower compartment situated in the core is filled with gas under pressure and is provided with a connection to the outside terminated by a closing member sensitive to the operating conditions of the reactor. If the reactor begins to malfunction, the closing member is destroyed thereby causing depressurization of the lower compartment and the precipitation of the liquid absorbent into the lower compartment.

Abstract: A cooling circuit for the main reactor vessel is limited on one side by the main vessel and a flow-reversing baffle shell and on the other side by the flow-reversing baffle shell and a counter-baffle shell which surrounds the primary vessel. The cooling circuit is supplied with a fraction of the cold liquid metal which is present within an intervessel space between the counter-baffle shell and the primary vessel. An annular chamber is located above the cold liquid metal and filled with an inert gas at a pressure which maintains the gas/liquid metal interface below the top of the flow-reversing baffle shell.

Abstract: Hot source having slight bulk consisting essentially of a flattened tube commonly spirally wound on a central tube and in fluid communication therewith at the same time as a grating providing, for the flame of a burner, a passage between the turns of the tube. The assembly is placed in a cylindrical ferrule (hoopring).