Abstract: The method of launching natural circulation of the liquid metal coolant in the heat sink circuit of the fast neutron nuclear reactor without connection to the main heat source (first circuit heat sink) and without using pumping equipment, but only as a result of electric heating of the downing and lifting sections of the heat sink circuit to the specified temperatures and, as a consequence, the occurring difference in the densities of the coolant on the lifting and downing sections of the heat sink circuit.

Abstract: Nuclear reactor systems and methods are described having many unique features tailored to address the special conditions and needs of emerging markets. The fast neutron spectrum nuclear reactor system may include a reactor having a reactor tank. A reactor core may be located within the reactor tank. The reactor core may include a fuel column of metal or cermet fuel using liquid sodium as a heat transfer medium. A pump may circulate the liquid sodium through a heat exchanger. The system may include a balance of plant with no nuclear safety function. The reactor may be modular, and may produce approximately 100 MWe.

Abstract: The invention relates to an assembly for exchanging heat between first and second fluids, the assembly comprising a central manifold communicating with one of the inlet and the outlet for the first fluid; an annular manifold disposed around the central manifold and communicating with the other one of the inlet and the outlet for the first fluid; a plurality of heat exchangers interposed radially interposed between the central manifold and the annular manifold; and a plurality of axial inlet manifolds communicating with the inlet for the second fluid, and a plurality of axial outlet manifolds communicating with the outlet for the second fluid, the axial inlet and outlet manifolds being interposed circumferentially between the heat exchangers. According to the invention, the assembly has an inlet chamber disposed at a first axial end of the heat exchangers and putting the inlet(s) for the second fluid into communication with at least a plurality of axial inlet manifolds.

Abstract: A heat exchanger, methods therefor and a nuclear fission reactor system. The heat exchanger comprises a heat exchanger body defining an exit plenum chamber therein shaped for uniform flow of a hot primary heat transfer fluid through the chamber. A plurality of adjacent heat transfer members are connected to the heat exchanger body and spaced apart by a predetermined distance for defining a plurality of flow passages between the heat transfer members. The flow passages open into the exit plenum chamber. Spacing of the heat transfer members by the predetermined distance evenly distributes flow of the primary heat transfer fluid through the flow passages, across the surfaces of the heat transfer members and into the exit plenum chamber. Each heat transfer member defines a flow channel therethrough for flow of a cooler secondary heat transfer fluid.

Abstract: A heat exchanger, methods therefor and a nuclear fission reactor system. The heat exchanger comprises a heat exchanger body defining an exit plenum chamber therein shaped for uniform flow of a hot primary heat transfer fluid through the chamber. A plurality of adjacent heat transfer members are connected to the heat exchanger body and spaced apart by a predetermined distance for defining a plurality of flow passages between the heat transfer members. The flow passages open into the exit plenum chamber. Spacing of the heat transfer members by the predetermined distance evenly distributes flow of the primary heat transfer fluid through the flow passages, across the surfaces of the heat transfer members and into the exit plenum chamber. Each heat transfer member defines a flow channel therethrough for flow of a cooler secondary heat transfer fluid.

Abstract: A heat exchanger, methods therefor and a nuclear fission reactor system. The heat exchanger comprises a heat exchanger body defining an exit plenum chamber therein shaped for uniform flow of a hot primary heat transfer fluid through the chamber. A plurality of adjacent heat transfer members are connected to the heat exchanger body and spaced apart by a predetermined distance for defining a plurality of flow passages between the heat transfer members. The flow passages open into the exit plenum chamber. Spacing of the heat transfer members by the predetermined distance evenly distributes flow of the primary heat transfer fluid through the flow passages, across the surfaces of the heat transfer members and into the exit plenum chamber. Each heat transfer member defines a flow channel therethrough for flow of a cooler secondary heat transfer fluid.

Abstract: An integral pressurized water nuclear reactor for the production of steam utilizing a helical coil steam generator, a plurality of internal circulation pumps, and an internal control rod drive mechanism structure.

Abstract: A nuclear reactor module includes a reactor vessel containing coolant, a reactor core submerged in the coolant, and a heat exchanger configured to remove heat from the coolant. The nuclear reactor module further includes one or more heaters configured to add heat to the coolant during a startup operation and prior to the reactor core going critical.

Abstract: A decay heat removal system for a liquid metal reactor in which a decay heat exchanger (DHX) is installed concentrically with an intermediate heat exchanger (IHX) in the same cylinder which separates the DHX and IHX from the reactor pool fluid, and serves to remove the reactor core decay heat. The cylinder surrounds the IHX and DHX, and has an open top portion protruding out of the level of the fluid in a hot pool, a bottom portion connected to a cold pool and a guide pipe for allowing the passage of the fluid from the hot pool into the IHX. The decay heat removal system can remove decay heat immediately after occurrence of an accident, thereby improving the safety of a nuclear plant.

Abstract: A decay heat removal system for a liquid metal reactor, in which a decay heat exchanger (DHX) is installed concentrically with an intermediate heat-exchanger (IHX) in the same cylinder which separates the DHX and IHX from the reactor pool fluid, and serves to remove the reactor core decay heat. The cylinder surrounds the IHX and the DHX, and has an opened top portion protruded out of the level of the fluid in a hot pool, a bottom portion connected to a cold pool and a guide pipe for allowing the passage of the fluid from the hot pool into the IHX. The decay heat removal system can remove decay heat immediately after occurrence of an accident, thereby improves the safety of a nuclear plant.

Abstract: A nuclear reactor in which a secondary or tertiary coolant system of a nuclear steam supply system is simplified, comprising: a reactor vessel (2) which integrates a reactor core (1); a first coolant (3) which is stored in the reactor vessel (2) and heated by the reactor core (1) to convect; a first heat transfer tube (4) which is arranged in the reactor vessel (2) and comes into contact with the first coolant (3); and a second coolant (5) which is supplied from the outside of the reactor vessel (2) to the first heat transfer tube (4), cools the first coolant (3) and led to the outside of the reactor vessel (2).

Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving apertures formed therein. Each aperture has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.

Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving aperture formed therein. Each apertures has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.

Abstract: Passive emergency cooling in response to a loss of coolant accident (LOCA) in a PWR, having an integral reactor pressure vessel incorporating the steam generators and housed in a small high pressure containment vessel, is provided by circulating cooling water through the steam generators and heat exchangers in an external tank to cool the reactor vessel at a rate sufficient to lower the pressure in the reactor vessel below that in containment to reverse mass flow out of the reactor vessel and keep the reactor core covered without the addition of makeup water. Suppression tanks inside the small high pressure containment structure limit peak blowdown pressure in containment and provide flood-up water and gravity fed makeup water to cool the core. Diverse cooling is provided by natural circulation of air, and if needed, water, over the spherical containment structure.

Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving apertures formed therein. Each apertures has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.

Abstract: There is provided a nuclear power station primary pump of the type comprising a drive shaft for rotating a wheel, a heat exchanger, a thermal barrier cover comprising a peripheral skirt provided at its base with a circular end wall, and a diffuser comprising a peripheral skirt provided at its base with a rim. The circular end wall co-operates with the base of the heat exchanger to define a bottom chamber for cold water and includes a central bore provided with a succession of circumferential and superposed rings forming a lip seal of the labyrinth type, and a space is formed between the thermal barrier cover and the diffuser to maintain stagnant cooling fluid.

Abstract: A liquid metal nuclear reactor is described. The reactor includes a concrete reactor silo, and at least one primary vessel located in the reactor silo and coupled to a reactor shield deck. Each primary vessel is substantially surrounded by a containment vessel in a spaced apart relationship. The reactor also includes a heat removal system which includes a guard vessel substantially surrounding each containment vessel in a spaced apart relationship, at least one inlet conduit in fluid communication with the ambient atmosphere outside the nuclear reactor, and at least one outlet conduit in fluid communication with the ambient atmosphere outside the nuclear reactor. A fluid flow heat transferring flowpath is formed by the inlet conduits, the space intermediate the guard vessel of each primary vessel and the containment vessel of each primary vessel and the outlet conduits.

Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving apertures formed therein. Each apertures has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.

Abstract: Segmented stayrod for restricting transverse displacement of a nuclear heat exchanger tube support plate. The stayrod includes a first rod segment interposed between the tubesheet and the first support plate, the first rod segment having an externally threaded riser extending through the hole formed in the first support plate. The stayrod also has a second rod segment interposed between the first support plate and the second support plate, the second rod segment having an internally threaded end portion for threadably engaging the threaded riser of the first rod segment. The second rod segment also has an externally threaded riser extending through the hole formed in the second support plate. An internally threaded fastener threadably engages the riser of the second rod segment for fastening the second rod segment to the second support plate. In this manner, the first support plate is captured between the first rod segment and the second rod segment.

Abstract: Apparatus and method for removing a wall portion from a wall of a tubular member. The wall portion has a distal end portion and a proximal end portion. The wall portion is connected to the wall of the tubular member by a pair of ligatures, which remain after use of a suitable cutting tool. The ligatures are aligned and disposed on either side of the wall portion to define a pivot axis. The apparatus has a probe body insertable into the tubular member, which probe body includes an expandable bladder for pushing the distal end portion of the wall portion in order to pivot the wall portion about the ligatures (i.e., about the pivot axis) as the bladder expands. As the wall portion pivots, the distal end portion of the wall portion rotates outwardly from the wall of the tubular member as the proximal end portion of the wall portion rotates inwardly into the tubular member. A movable elongate mandrel engages the proximal end portion of the wall portion.

Abstract: A system for mapping absolute acoustic noise intensity in a three-dimensional acoustic noise field, and using three-dimensional absolute noise intensities to infer operational or performance characteristics of components or structures within the monitored field. Localized noise sources are extracted using a distant array of transducers, and the absolute intensity can be measured even when totally masked by background noise at the transducer locations. The system includes an integrated sensor installation; a neural network detection system algorithm; a zoom system to precisely examine a small region in the steam generator vessel; a fuzzy logic system detection algorithm; and an expert detection system. The signal processing subsystem operates at three different levels of detection. At the top level of detection a trained neural network system monitors the vessel length for any indication of a leak. The proposed approach uses discriminators which do not require any beamforming of the sensor signals.

Abstract: A supercritical water oxidation reactor includes a vessel with an interior urface, two cooling sections, a heat exchanger, an oxygenating section, a pump, and a trap. The interior surface of the vessel has a corrosion-resistant, artificial ceramic or diamond-like coating. The artificial diamond coating is thin and crystal-like in structure. The heat exchanger is located between the two cooling sections. The heat exchanger and the two cooling sections surround the exterior of the vessel. The oxygenating section comprises a porous cylindrical baffle positioned within the vessel. The porous baffle transfers oxygen, hydrogen peroxide, or other oxygenating substances to an aqueous hazardous waste introduced into the reactor.In accordance with another aspect of the invention, the oxygenating section includes a shaft having a helical extension. The shaft has a corrosion-resistant, artificial diamond or diamond-like coating on its outer surface.

Abstract: The nuclear reactor includes a fuel core (5) inside a vessel (2) and a system (1) for cooling the core (5), in which a liquid metal circulates and on which is placed at least one steam generator (15). The steam generator includes a casing (15a) in which the liquid metal circulates, water-feed means (16) and means for heat exchange between the liquid metal and the feed water. The liquid metal is caused to circulate in the cooling system (1), the steam generator (15) not being fed with water and the liquid metal circulating in the steam generator (15) is cooled by the flow of a gas in contact with the casing (15a) of the steam generator (15). The cooling device includes a tubular element (25) placed around the casing (15a) of the steam generator and defining an annular space for a cooling gas to flow around the casing (15a).

Abstract: A pressurized water reactor plant includes a reactor vessel (1), a reactor coolant pump (5) having an inlet connected by coolant pipe (2) to an outlet of the reactor vessel, a steam generator (10) having an inlet connected by a high-temperature side pipe (4) to the outlet of the pump (5) and an outlet connected by low-temperature side pipe (6) to an inlet of the reactor vessel. The steam generator has a horizontally extending shell (11) in the interior of which are horizontal U-shaped tube bundles (30) supported on tube support plates (20) and a pair of separator plates (18) which divide the interior of the shell into downcomer space (19). A partition plate (21) divides the interior of the shell into a U-shaped tube region (16) and a straight tube region (17). A moisture separator (27) is disposed above the heat transfer tubes (15) and a drain pipe (28) extends therefrom for draining impurities from the moisture separator to the U-shaped tube region (16) to which blowdown pipe (26) is connected.

Abstract: A steam generator with a heat exchanger in which the tube openings of the support plate are oversized relative to the outer diameter of the heat exchanger tubes, to facilitate assembly of the heat exchanger, and in which a positive contact preloading of the heat exchanger tubes in opposite directions is produced, once the steam generator goes to operating temperatures and pressures, by a mounting of the support plates which causes them to pull on the heat exchanger tubes in opposites directions so as to provide a passive, positive supporting of the heat exchanger tubes by the supporting plates which eliminates cross flow induced vibrations during operation, pressures despite the existence of clearance gaps between the heat exchanger tubes and the support plates through which they pass at ambient temperatures and pressures.

Abstract: A sodium cooled fast ractor comprises a reactor vessel in which a liquid metal coolant is accommodated, a core disposed substantially a lower central portion of the reactor vessel in an installed state, a core support structure secured to the reactor vessel for supporting the core, the core support structure dividing an interior of the reactor vessel into a high-pressure plenum below the core and a low-pressure plenum above the high-pressure plenum, a circulation pump unit for applying a discharge pressure to the liquid metal coolant and circulating the same, and an intermediate heat exchanger for performing a heat exchanging operation of the coolant in the reactor vessel. The circulation pump unit is composed of an electromagnetic circulation pump provided with a discharge port and a closed gas space, which is filled up with a closed gas, defined above and communicated with the discharge port.

Abstract: A steam generator utilized for a liquid-metal coolant reactor comprises an outer shell body in which an electromagnetic pump is arranged. The electromagnetic pump comprises a hollow cylindrical iron core provided with comb-shaped portion at an outer peripheral surface thereof and an annular stator coil means assembled in the comb-shaped portion of the cylindrical iron core. A main passage of liquid metal is formed on a side on which the stator coil of the iron core is assembled and a cooling bypass passage is formed at substantially the central portion of the cylindrical iron core in a vertically penetrating fashion.

Abstract: The invention refers to a solution for the reactor block of a sodium-cooled fast reactor, fitted with an inner cylindrical vessel. This forms the mechanical structure for hydraulic separation 7 between the primary sodium hot header 2 and the cold header 3. The hot header is located in the area above the core, and the cold header, having a larger volume and an annular shape, is located all around the hot header. According to the invention the primary pumps and intermediate exchangers 8 are immersed in the cold header 3. The intermediate heat exchangers 8 are of the straight tube bundle type, with primary sodium outside the tubes, and they are hydraulically connected to the hot header by a transverse duct 13, solid with the inner cylindrical vessel 7, and mechanically sealed where it interfaces with the heat exchanger. This mechanical sealing system is made as close against the heat exchanger, as possible, so that the heat exchanger is removable.

Abstract: A magnet pump has a magnet coupling for magnetically coupling an inner ring yoke and an outer ring yoke so as to magnetically transmit a torque from driving part to driven part of the pump to rotate the driven part. The magnet pump comprises magnetized magnet pieces bonded to the outer peripheral surface of the inner ring yoke and magnetized magnet pieces bonded to the inner peripheral surface of the outer ring yoke; non-magnetic cylindrical covers covering the surface of the inner ring yoke carrying the magnet pieces and the surface of the outer ring yoke carrying the magnet pieces, respectively; and mold resin parts filling the gap between the surface of the inner ring yoke and the associated non-magnetic cylindrical cover and the gap between the surface of the outer yoke ring and the associated non-magnetic cylindrical cover.

Abstract: An autonomous, decentralized fast breeder reactor includes a single reactor main vessel which houses a plurality of small-size reactor subsystems each having a small-scale fast breeder reactor core, and a plurality steam generator subsystems. These subsystems function in an autonomous manner and are caused to undergo a heat transfer with one another by a coolant circulating naturally through the interior of the main vessel, thereby constructing a cooperatively operating system. Steam generated by the steam generators is introduced to a turbine system and utilized in generating electricity. The condensate from the turbines is cooled by a heat accumulating pool, and the heat is utilized in a separate system. The entire system is installed underground and use is made of the difference in elevation. Use also is made of solid bedrock to construct a housing facility for the reactor.

Abstract: In a steam generator utilized with a liquid sodium cooled nuclear reactor, provision is made to vent the violent sodium water reaction emanating from a tube rupture casualty. The steam generator includes a sodium plenum at the bottom thereof containing a conventional rupture disk for venting sodium, steam, and reaction products including hydrogen immediately upon a tube rupture casualty. The invention includes providing an alternate concentric flow path interior to the steam generator and parallel to the tube bundle. This alternate concentric flow path extends from the upper portion of the steam generator down into the lower head or plenum adjacent to the pressure relief diaphragm. This alternate path is partially filled with sodium during normal reactor operation.

Abstract: An intermediate heat transport system is disclosed for providing steam generation from the secondary nonradioactive liquid sodium heat extraction loop from a sodium cooled nuclear reactor. The transport system includes a unitary module combining the steam generating heat exchanger, the pump for the circulation of the liquid sodium coolant, and the surge volume required for differential expansion between the sodium and the vessels that contain the sodium. Two concentric cylindrical and vertically standing vessels are provided for containing the liquid sodium; one vessel is outer and larger; the other inner vessel is of a double wall construction and open on its lower end hung from the top of the longer vessel. The outer and larger cylindrical vessel has four feedwater inlet plenums (typical number) at the bottom and four steam outlet plenums at the top. Tube sheets terminate each plenum to a tube bundle extending between the inlet and outlet plenums.

Abstract: Device for condensing steam under pressure consisting of a unit incorporating a storage vessel (6) containing cooling water, a distribution and heat exchange unit (15) fixed inside the storage vessel (6) and a water supply (30,31) for replacing the water in a storage tank (6) which is vaporized by contact with the tubes (24) of the distribution and heat exchange unit (15). A stack (7) is connected to the upper part of the storage vessel (6) and a tranquilizer grid is arranged in the storage vessel, above the heat exchange unit (15). The circulation of the fluid which is constituted of a two-phase mixture of water and steam is thus activated, while avoiding drawing out a significant quantity of water with the steam.

Abstract: A liquid metal cooled pool type nuclear reactor incorporates an emergency heat exchanger having a novel geometry. The heat exchanger comprises circular and annular tube plates coaxially aligned. The tube bundle has a vertical straight part connected to the central tube plate, a bent horizontal circular portion extending over one-third of the heat exchanger's circumference for returning the bundle, and a vertical straight return part joining the peripheral tube plate.

Abstract: A metal brazing sleeve includes a ceramic flux band formed on the sleeve adjacent an annular recess typically disposed near an open end of the sleeve for receiving a conventional braze preform, by adhering a powder flux to the sleeve by a tacky adhesive and then melting the powder flux in place, by internal heating of the tube. The ceramic flux band is hard and adherent, and resistant to abrasion effects during insertion of the sleeve into a tube, and provides a shadow effect for protecting an optional cemented powder flux band which may be formed on the braze ring.

Abstract: A double tube modular coil steam generator is provided in which a multiplicity of inner tubes conducting water are individually surrounded by outer tubes containing liquid metal as a heat transfer agent. The double tubes form into coils, providing a large surface area while conserving space. Immersion of the double tube coil in hot liquid metal, e.g., from the core of a nuclear reactor, causes efficient transfer of heat across the liquid metal in the outer tube to the water in the inner tube, creating superheated steam, which can be cycled to a turbine and converted to electrical power.The efficiency, reliability and safety of the multiple double tube design of the steam generator obviates the necessity of many secondary heat removal and emergency components in addition to conserving space and material. The modular design allows ease of operation, fabrication and repair.

Abstract: A nuclear reactor is provided characterized by a circulating liquid metal cooling system comprising a heat exchanger having a closed intermediate heat transfer fluid circuit in the form of a helical coil juxtaposed with the liquid metal coolant system, which effectively transfers heat through the intermediate circuit to a secondary fluid circuit. The intermediate heat transfer fluid circuit, which completely separates the liquid metal cooling system from the secondary fluid circuit, prevents potentially dangerous reactions between the primary liquid metal coolant and the secondary fluid (e.g., water).The efficiency, reliability and safety of the heat exchanger features eliminates the need for many secondary heat removal and emergency components in the design of the nuclear reactor.

Abstract: Fast neutron nuclear reactor of the type comprising a primary circuit integrated into a liquid metal-filled vessel and containing the reactor core, as well as means for circulating the said liquid metal and means for transferring the heat carried by the liquid metal to the water circulating in a water/steam circuit, wherein the heat transfer means comprise at least one steam generator located in the reactor vessel and having at least one group of inner tubes in which circulates the water of the water/steam circuit, at least one group of outer tubes immersed in the primary liquid metal, the outer tube surrounding each of the inner tubes in order to define therewith an annular space under a neutral gas pressure, connected to secondary circuit with a low thermal power having means for circulating this pressurized neutral gas, such as helium in said annular space and ensure the heat exchange.

Abstract: The invention relates to a heat exchanger incorporating emergency cooling means, as well as to a fast neutron nuclear reactor incorporating such an exchanger.The emergency cooling means comprise an inlet pipe issuing into the secondary fluid inlet chamber and an outlet pipe issuing into the secondary fluid outlet chamber. The inlet pipe issues into a distributing ramp positioned below the lower tue plate and the outlet pipe issues into a collecting ramp positioned above the upper tube plate. The two ramps are positioned below the intake and discharge pipes for the secondary fluid.

Abstract: The invention relates to a device for thermal protection of a component of a fast-neutron nuclear reactor consisting of at least one shell (10, 11) of a diameter smaller than the diameter of the passage (2) for the component (4) but greater than the diameter of the component (4). The length of the shell (10, 11) fixed under the flange (5) of the component (4) is greater than the slab thickness (1). Circulation of blanket gas (13) is established in the annular space (7) between the component (4) and the passage (2).The invention applies in particular to nuclear reactors cooled with liquid sodium whose upper level is under an argon blanket.

Abstract: Fast neutron nuclear reactor, which comprises a vessel containing a liquid cooling metal, a core immersed in this metal, the vessel having a flooring on which rests a structure for the core, said core being constituted by a juxtapositioning of assemblies fixed into the structure, the liquid cooling metal circulating in an upwards manner in the core, the liquid metal being called "cold liquid metal" before its circulation in the core and "hot liquid metal" after it has passed into the latter, wherein it comprises a fuel element storage structure, which is independent of the core structure and is arranged concentrically with respect to the latter and rests on the flooring, a circulation of cold liquid metal being ensured in the assembly by recovering leaks of the core structure.

Abstract: Device for the homogeneous mixing of liquids flowing at different temperatures comprising a member connected to an inlet tube and to an outlet tube of a main circuit in which circulates a hot liquid, a cylindrical inlet of the member being connected to a secondary tube of a secondary circuit in which circulates a cold liquid, a cylindrical circuit sealingly fixed to the member on the outlet side thereof and having openings on the inlet tube side, wherein (1) an envelope formed, as from the inlet tube, by a cylindrical part, a frustum-shaped part and a cylinder surrounds the cylindrical pipe providing an annular space with the latter over part thereof located on the side of the inlet tube and having the said openings; (2) the envelope forms a first annular channel with the member; (3) a connecting tube connected to the secondary tube and to the cylinder forms, with a cylindrical inlet of the member, a second annular channel linked to the first annular channel; and (4) the cylindrical pipe has a series of holes

Abstract: Nuclear reactor cooled by a liquid metal comprising a main vessel sealed by a sealing slab, said vessel containing liquid metal overhung by a covering of inert gas, the reactor core being placed in a primary vessel integrated into the main vessel in such a way that the primary vessel at the outlet from the core constitutes a hot collector for the liquid metal and the space defined between the main vessel and the primary vessel constitutes a cold collector for the liquid metal, at least one heat exchanger supplied by the liquid metal contained in the hot collector under the action of at least primary pumps located in the main vessel, wherein the exchanger is positioned outside the main vessel at a level above that of the sealing slab and communicates with the hot collector by at least one intake pipe and with the cold collector by at least one outlet pipe, it being possible to empty the exchanger and pipes into the main vessel by gravity, the upper part of each exchanger being filled with the inert gas coverin

Abstract: Device for the emergency removal of the heat dissipated by a fast breeder nuclear reactor when shut down, comprising a liquid-liquid heat exchanger immersed in the vessel of the reactor and a liquid-air exchanger for the cooling of the secondary liquid of the latter exchanger. The liquid-liquid comprises a casing composed of a sleeve (18,19) having openings (21,22) for the natural circulation of the cooling fluid of the reactor in contact with the tubes (25) of a nest (20) disposed in the casing of the exchanger. Each of the tubes (25) includes a straight input section and a long straight return section, separated by a helically wound section forming a loop with a low number of turns, inclined to a small extent with respect to the horizontal plane. The coil diameter of the tubes (25) is constant and identical for all the tubes and very slightly less than the interior diameter of the sleeve (18,19).The invention applies in particular to liquid sodium-cooled fast breeder nuclear reactors.

Abstract: An emergency cooling device for a water-cooled nuclear reactor comprises a heat exchanger integrated into a reactor vessel and submerged in the reactor water. One of the ends of the circuit of this exchanger is connected by means of a three-way valve to the upstream valve, while its other end is connected across a downstream valve and a second untreated water-operated cooling exchanger to the cold water tank.

Abstract: The invention relates to a pool-type fission reactor power plant design having a reactor vessel containing a primary coolant (such as liquid sodium), and a steam expansion device powered by a pressurized water/steam coolant system. Heat pipe means are disposed between the primary and water coolants to complete the heat transfer therebetween. The heat pipes are vertically oriented, penetrating the reactor deck and being directly submerged in the primary coolant. A U-tube or line passes through each heat pipe, extended over most of the length of the heat pipe and having its walls spaced from but closely proximate to and generally facing the surrounding walls of the heat pipe. The water/steam coolant loop includes each U-tube and the steam expansion device. A heat transfer medium (such as mercury) fills each of the heat pipes.

Abstract: The invention relates to a fast neutron nuclear reactor of the integrated type comprising a cylindrical inner vessel.The inner vessel comprises two concentric ferrules and the connection between the hot collector defined within this vessel and the inlet port of the exchangers is brought about by a hot structure forming a heat baffle and supported by the inner ferrule and by a cold structure surrounding the hot structure, supported by the outer ferrule and sealingly connected to the exchanger.Application to the generation of electric power in nuclear power stations.

Abstract: The invention relates to a fast neutron nuclear reactor equipped with residual power removal devices.Each device comprises an evaporator incorporating a bundle of tubes in glove finger-like form immersed in the liquid metal contained in the reactor vessel, an adiabatic collector constituted by a pipe traversing the slab sealing the reactor vessel and a condenser in which the heat transfer fluid, such as mercury, contained in said device is condensed by heat exchange with the atmospheric air sucked in through the chimney or flue.Application to fast neutron nuclear reactors.

Abstract: A moisture separator reheater having a central chamber with cylindrical wall portions and a generally round tube bundle, the tube bundle having arcuate plates disposed on each side of the bundle which form a wrapper on each side of the tube bundle and having a tongue and groove juncture between the wrapper and cylindrical wall portions to provide a seal therebetween and a track for installing and removing the tube bundle from the central chamber.

Abstract: A nuclear reactor having integral heat exchangers comprises intermediate heat exchangers (35) which are entirely contained within the reactor vessel (1) and bear on the support (4) for the reactor core (5) at the periphery of the latter. Each one of the intermediate heat exchangers (35) is connected to the secondary liquid sodium circuit by a conduit (50) which passes through a slab (8) closing off the top of the reactor. An upper rotating stopper (15) includes an opening (53) of a size which is comparable to that of the cross-section of an intermediate heat exchanger (35), the opening being located at such a distance from the axis of rotation (12) of the stopper that the opening (53) can be brought into vertical alignment with each one of the intermediate heat exchangers (35) in succession. The invention particularly relates to fast neutron reactors which are cooled with liquid sodium.