Abstract: A power module assembly may include a reactor vessel containing a primary coolant and one or more inlets configured to draw a secondary coolant from the containment cooling pool in response to a loss of power and/or a loss of coolant. One or more outlets may be submerged in the containment cooling pool and may be configured to vent the secondary coolant into the containment cooling pool. A heat exchanger may be configured to remove heat from the primary coolant, wherein the heat may be removed by circulating the secondary coolant from the containment cooling pool through the heat exchanger via natural circulation.

Abstract: A nuclear power system includes a reactor vessel that includes a reactor core mounted therein. The reactor core includes nuclear fuel assemblies configured to generate a nuclear fission reaction. The reaction vessel does not include any control rod assemblies therein. The nuclear power system further includes a riser positioned above the reactor core, a primary coolant flow path, a primary coolant that circulates through the primary coolant flow path to receive heat from the nuclear fission reaction and release the received heat to generate electric power in a power generation, and a control system communicably coupled to the power generation system and configured to control a power output of the nuclear fission reaction independent of any control rod assemblies.

Abstract: A molten chloride fast reactor (MCFR) includes a plurality of reflectors defining a central core having a core geometric center. A flow channel fluidically connected to the central core. The flow channel includes an outlet flow channel downstream of the central core and an inlet flow channel upstream from the central core. A primary heat exchanger (PHX) disposed outside the central core and between the outlet flow channel and the inlet flow channel. The MCFR also includes a decay heat heat exchanger (DHHX). At least a portion of the DHHX is disposed above the core geometric center, and a fuel salt is configured to circulate at least partially through the outlet flow channel, the DHHX, the PHX, the inlet flow channel, and the central core.

Abstract: A feed water distributing system for a nuclear power plant contains feed water distributers disposed within a reactor pressure vessel. The feed water distributing system has a consistent feed water distribution when starting up and during a partial load operation with low mechanical loads and has a redundancy of the individual components while maintaining the customary level of reliability in nuclear power plants. Each feed water distributer has exactly one annular main body with an inner channel, at least one fill socket which is fluidically connected to the inner channel via at least one fill opening, and a plurality of outlet nozzles which are fluidically connected to the inner channel. Each of the fill sockets of one feed water distributer is fluidically connected to each outlet nozzle of the feed water distributer.

Abstract: A fuel bundle flow limiter according to a non-limiting embodiment of the present invention may include a plurality of base sections, wherein each of the plurality of base sections has at least one opening. A plurality of channels may separate the plurality of base sections. A plurality of vertical webs may extend from the plurality of base sections. A locking tab may be disposed in at least one of the plurality of vertical webs. By using the flow limiter, the moisture carry over (MCO) level at the exit of the fuel bundle may be decreased, thereby reducing radiation exposure to plant operators and reducing damage to reactor equipment.

Abstract: A nuclear reactor primary circuit with a branch equipped with a thermal sleeve is provided. The nuclear reactor primary circuit includes a primary tubing, having an inner surface delimiting an inner volume in which a primary fluid circulates for cooling the nuclear reactor; a branch fastened to the primary tubing and delimiting an inner passage communicating with the inner volume of the primary tubing; a sleeve, having a first end connected to the branch and a second free end engaged in the inner volume of the primary tubing, the second end protruding in the inner volume relative to the inner surface over a non-zero length, an annular space being delimited between the sleeve and the branch.

Abstract: A high-temperature nuclear reactor, cooled by a liquid fluoride salt, is described. The reactor uses an annular fuel pebble comprised of an inert graphite center kernel, a TRISO fuel particles region, and a graphite outer shell, with an average pebble density lower than the density of the liquid salt so the pebbles float. The pebbles are introduced into a coolant entering the reactor and are carried into the bottom of the reactor core, where they form a pebble bed inside a plurality of vertical channels inside one or more replaceable Pebble Channel Assemblies (PCAs). Pebbles are removed through defueling chutes located at the top of each PCA. Each PCA also includes channels for insertion of neutron control and shutdown elements, and channels for insertion of core flux mapping and other instrumentation.

Abstract: A pressurized water reactor (PWR) includes a pressure vessel containing a radioactive core immersed in primary coolant water. A reactor coolant pump (RCP) disposed in a downcomer annulus of the PWR includes a jet pump and an electric pump whose impeller is disposed at the jet pump injector inlet. The electric pump includes a canned electric motor that is disposed in the downcomer annulus. In another RCP embodiment, the jet pump is omitted and the electric pump is seated in a flow distributor with the impeller of the seated RCP disposed in an impeller plenum defined by the flow distributor. The flow distributor further defines a fluid flow path with one or more branches extending from an inlet and running alongside but not through the canned electric motor of the seated RCP to discharge into the impeller plenum containing the impeller of the seated RCP.

Abstract: A pressurized water reactor (PWR) includes a pressure vessel and a nuclear reactor core disposed in the pressure vessel. A baffle plate is disposed in the pressure vessel and separates the pressure vessel into an internal pressurizer volume disposed above the baffle plate and an operational PWR volume disposed below the baffle plate. The baffle plate comprises first and second spaced apart plates and includes a pressure transfer passage having a lower end in fluid communication with the operational PWR volume and an upper end in fluid communication with the internal pressurizer volume at a level below an operational pressurizer liquid level range. A vent pipe has a lower end in fluid communication with the operational PWR volume and an upper end in fluid communication with the internal pressurizer volume at a level above the operational pressurizer liquid level range.

Abstract: A pressurized water reactor comprises a reactor pressure vessel (11), a cylindrical core barrel (13), a core disposed in the core barrel (13), a lower core support plate (17), and a cylindrical porous plate (31). The core barrel (13) is provided in the reactor pressure vessel (11) and forms, with the inner side surface of the reactor pressure vessel (11), an annular downcomer (14) therebetween. The lower core support plate (17) is provided under the core so as to extend horizontally, and a large number of upward flow holes (80) are formed therein. The cylindrical porous plate (31) demarcates a lower plenum (16) and a bottom part of the downcomer (14), and a plurality of inward flow holes (83) that serve as flow paths from the bottom part of the downcomer (14) to the lower plenum (16) are formed therein. The inward flow holes (83) are inclined upward to the lower plenum (16) on the side on which the inward flow holes are open to the lower plenum (16).

Abstract: A nuclear reactor having a liquid metal or molten salt coolant in a riser space 130?, has a cylindrical containment vessel 134 with a reactor vessel 120?, at least two lobes 121, preferably three to nine lobes 121, each lobe 121 interconnected with the other lobe(s) and each containing a fast reactor core, 116?, 116?, 116? and 116??.

Abstract: An integral pressurized light water reactor having most of the components of a primary side of a pressurized water reactor nuclear steam supply system housed in a single pressure vessel with a pressurizer separated from the remaining reactor system by a surge separator having multiple layers of separated steel plates with a number of concentric baffles extending therebetween. A circuitous flow path is provided through and between the plates and concentric baffles and a relatively stagnant pool of coolant is maintained within an innermost zone between the plates to provide thermal isolation.

Abstract: In a nuclear reactor core having fuel assemblies with upper and lower end fittings, a debris filter plate is attached to a lower end fitting having a skirt. The filter prevents debris from entering the fuel assembly, while the skirt prevents the trapped debris from sliding off the lower end fitting and continuing into the core. The lower end fitting is formed from a substantially square base and has flow channels to allow coolant to flow through it to the fuel assembly. The skirt is an extension of the metal of the lower end fitting that extends around the perimeter of the lower end fitting, spanning all four corners of the lower end fitting. In addition to capturing debris, the skirt also positions the filter, which may be manufactured from the same metal as the lower end fitting.

Abstract: A power module includes a reactor vessel containing a coolant and a reactor core located near a bottom end of the reactor vessel. A riser section is located above the reactor core, wherein the coolant circulates past the reactor core and up through the riser section. In one embodiment, a coolant deflector shield includes flow-optimized surfaces, wherein the flow-optimized surfaces direct the coolant towards the bottom end of the reactor vessel. In another embodiment, the reactor housing includes an inward facing portion that varies a flow pressure of the coolant and promotes a circulation of the coolant past a baffle assembly and towards the bottom end of the reactor vessel.

Abstract: A power module includes a reactor vessel containing a coolant and a reactor core located near a bottom end of the reactor vessel. A riser section is located above the reactor core, wherein the coolant circulates past the reactor core and up through the riser section. In one embodiment, a coolant deflector shield includes flow-optimized surfaces, wherein the flow-optimized surfaces direct the coolant towards the bottom end of the reactor vessel. In another embodiment, the reactor housing includes an inward facing portion that varies a flow pressure of the coolant and promotes a circulation of the coolant past a baffle assembly and towards the bottom end of the reactor vessel.

Abstract: A core shroud is provided, which includes a number of planar members, a number of unitary corners, and a number of subassemblies each comprising a combination of the planar members and the unitary corners. Each unitary corner comprises a unitary extrusion including a first planar portion and a second planar portion disposed perpendicularly with respect to the first planar portion. At least one of the subassemblies comprises a plurality of the unitary corners disposed side-by-side in an alternating opposing relationship. A plurality of the subassemblies can be combined to form a quarter perimeter segment of the core shroud. Four quarter perimeter segments join together to form the core shroud.

Abstract: A pressurized water reactor (PWR) comprises: a nuclear core comprising a fissile material; a cylindrical pressure vessel having a vertically oriented cylinder axis and containing the nuclear core immersed in primary coolant water; and a hollow cylindrical central riser disposed concentrically with and inside the cylindrical pressure vessel. A downcomer annulus is defined between the hollow cylindrical central riser and the cylindrical pressure vessel. The hollow cylindrical central riser has a radially expanding upper orifice that merges into an annular divider plate that separates an upper plenum above the annular divider plate from a lower plenum below the annular divider plate. The upper plenum is in fluid communication with the radially expanding upper orifice and the lower plenum is in fluid communication with the downcomer annulus. A weir may extend away from a bottom wall of the lower plenum into the lower plenum.

Abstract: A fuel bundle flow limiter according to a non-limiting embodiment of the present invention may include a plurality of base sections, wherein each of the plurality of base sections has at least one opening. A plurality of channels may separate the plurality of base sections. A plurality of vertical webs may extend from the plurality of base sections. A locking tab may be disposed in at least one of the plurality of vertical webs. By using the flow limiter, the moisture carry over (MCO) level at the exit of the fuel bundle may be decreased, thereby reducing radiation exposure to plant operators and reducing damage to reactor equipment.

Abstract: A fast reactor 1 includes: a reactor vessel 7 accommodating therein a core 2 and a primary coolant 21; a core support 13 supporting the core 2 from below; and a bulkhead 6 disposed on the core support 13, the bulkhead 6 extending upward and surrounding the core 2 from a lateral side. Between an inner surface of the reactor vessel 7 and the bulkhead 6, there is disposed an intermediate heat exchanger 15 configured to cool the primary coolant 21, and an electromagnetic pump 14 configured to pressurize the cooled primary coolant 21. A neutron shield 8 supported by an upper supporting plate 29 from above is disposed below the electromagnetic pump 14. The upper supporting plate 29 has an opening 29a. Between an outlet 14b of the electromagnetic pump 14 and the upper supporting plate 29, there is disposed a coolant guide mechanism 17 configured to guide the pressurized primary coolant 21 from the electromagnetic pump 14 to the neutron shield through the opening 29a of the upper supporting plate 29.

Abstract: In a corium cooling promoting apparatus and a containment, a pressurized water reactor (12) is contained inside the containment (11), and a cavity (56) to which cooling water can be supplied in an emergency is provided below the pressurized water reactor (12). The cooling promoting apparatus (61) is disposed in the cavity (56), and an inclined plate (62) for spreading a corium (debris) from the pressurized water reactor (12) is provided, as the cooling promoting apparatus (61), at a position below the pressurized water reactor (12) in the cavity (56). The cooling of the corium falling from the nuclear reactor is thereby facilitated, and the corium is cooled at an early stage to improve safety.

Abstract: The invention relates to a novel architecture for a nuclear reactor of the integrated type.

Abstract: An emergency core cooling system directly injects emergency core cooling water, which is supplied from a high-pressure safety injection pump or a safety injection tank for a pressurized light water reactor, into a reactor vessel downcomer. A pipe connector is completely removed from between each direct vessel injection nozzle and each injection extension duct installed on an outer surface of the core barrel, which are opposite to each other. An emergency core cooling water intake port, through which the water is injected from each direct vessel injection nozzle, is formed on the surface of each injection extension duct facing an axis of each direct vessel injection nozzle. Thereby, a structure in which a jet of the emergency core cooling water flows into the injection extension ducts is adopted in a hydraulic connection fashion.

Abstract: Disclosed embodiments include nuclear fission reactor cores, nuclear fission reactors, methods of operating a nuclear fission reactor, and methods of managing excess reactivity in a nuclear fission reactor.

Abstract: Illustrative embodiments provide nuclear fission fuel elements, and systems, applications, apparatuses, and methods related thereto. Illustrative embodiments and aspects include, without limitation, nuclear fission fuel elements, heat pipe assemblies, heat pipes, methods of fabricating a nuclear fission fuel element, methods of fabricating a heat pipe assembly, and the like.

Abstract: A method treats a flow gas that is guided via a catalytic adsorber module to oxidize contaminants carried in the flow gas. The method reliably purifies the flow gas using equipment that is held to a comparatively low level of complexity. To this end, the flow gas is guided in a first purification step via a first catalytic adsorber module to oxidize contaminants carried along therewith, during which molecular or atomic oxygen is added to the flow gas, and the flow gas mixed with the added oxygen is guided in a second purification step via an oxidation catalyst. The flow gas flowing away from the oxidation catalyst is guided in a third purification step via a second catalytic adsorber module to reduce excessive oxygen.

Abstract: A nuclear reactor having a coolant flow deflector secured to a reactor core barrel in line with a coolant inlet nozzle. The flow deflector redirects incoming coolant down an annulus between the core barrel and the reactor vessel. The deflector has a main body with a front side facing the fluid inlet nozzle and a rear side facing the core barrel. The rear side of the main body has at least one protrusion secured to the core barrel so that a gap exists between the rear side of the main body adjacent the protrusion and the core barrel. Preferably, the protrusion is a relief that circumscribes the rear side of the main body.

Abstract: In a nuclear reactor internal structure, generation and promotion of object-downstream separating vortices are suppressed so that coolant uniformly flows in a reactor core and pressure loss of flow of the coolant is reduced so that the flow of the coolant is stabilized. A lower connecting plate 30 arranged in a lower plenum 8 comprises a ring portion 31 in which an arcuate portion 32 and a cut-off portion are alternately formed. An outer peripheral portion of the ring portion 31 is asymmetric relative to a flow direction of main flow and also asymmetric relative to a separating flow generation direction.

Abstract: A compact pressurised water nuclear reactor comprises a primary circuit fully integrated into the reactor vessel (10). Thus, a single steam generator (12) forms the cover of the vessel (10) and the pressuriser (30) and the primary pumps (28) are housed in the vessel (10). The same is true for the control mechanisms of the control rods (40). Finally, a venturi system (44) is also provided in the vessel (10) to create water circulation if there is a failure of the primary pumps (28).

Abstract: A fluid pump utilizing a canned rotor and canned stator is provided. The fluid pump has increased insulative properties over past “spool-type” pumps and has an increased ability to cool the stator, making it suitable for high temperature applications. A nuclear reactor is also provided. The reactor comprises a reactor vessel, that contains a nuclear fuel, control rods, reactor coolant and a reactor coolant pump for providing the reactor coolant to a steam generator. In a preferred embodiment, a steam generator is also provided inside the reactor vessel.

Abstract: A method for transmuting spent fuel from a nuclear reactor includes the step of separating the waste into components including a driver fuel component and a transmutation fuel component. The driver fuel, which includes fissile materials such as Plutonium239, is used to initiate a critical, fission reaction in a reactor. The transmutation fuel, which includes non-fissile transuranic isotopes, is transmuted by thermal neutrons generated during fission of the driver fuel. The system is designed to promote fission of the driver fuel and reduce neutron capture by the driver fuel. Reacted driver fuel is separated into transuranics and fission products using a dry cleanup process and the resulting transuranics are mixed with transmutation fuel and re-introduced into the reactor. Transmutation fuel from the reactor is introduced into a second reactor for further transmutation by neutrons generated using a proton beam and spallation target.

Abstract: Within an upper plenum of a nuclear reactor, a portion of a heated coolant flows radially outward from a central portion of a core barrel (30) towards outlet nozzles (12) in a region of an upper core plate (21) extending outside of an outer periphery of the core along an inner wall of a core barrel (30). Portions of the coolant flows beneath the outlet nozzles (12). Thus, streams of heated coolant flowing in opposite directions may collide with each other. After collision, the flow directions of the heated coolant are changed to flow upward. Due to the collision, the coolant flow behavior becomes complicated and unstable, making it difficult to measure the temperature of the heated coolant with an outlet pipe (42) connected to the outlet nozzle (12).

Abstract: Plutonium is effectively and economically rendered unsuitable for employment in a device for creating a nuclear detonation. Weapons-grade plutonium is made into ceramic fuel in the form of spheroids of submillimeter size, coated with multi-layer fission-product-retentive coatings and disposed in sealed fuel chambers in graphite block fuel elements. These elements are used to form a core for a modular helium-cooled high temperature nuclear reactor which is operated to efficiently generate power by causing the hot high pressure helium coolant to drive a gas turbine directly connected to an electrical generator, which nuclear fuel core has about a 3-year lifetime. Spent nuclear fuel elements are removed at the end of 3 years and shifted to form the core for an accelerator-driven helium-cooled reactor wherein a subcritical core of spent fuel elements is safely caused to effectively continuously fission by a neutron flux created by a Linac which bombards a lead target with a beam of high energy protons.

Abstract: A forced-circulation boiling-water reactor includes bypass check valves between a downcomer and a core inlet plenum. When the recirculation pumps are operating at full capacity, there is a maximum pressure differential from the downcomer to the core inlet plenum. This pressure differential keeps the valves closed so that recirculating fluid is constrained to flow through the pumps. When the pumps are not operating, a driving water head in the downcomer forces the valves open, augmenting the flow cross section between the downcomer and the core inlet plenum, enhancing natural circulation. The enhanced natural circulation provides greater core stability during pump shutdown. The valves are selected or adjusted so that they open when the pressure differential falls through a predetermined range to augment diminished pumping capacity with a higher natural circulation flow rate.

Abstract: A nuclear reactor includes a spaced sidewall and a core shroud defining a flow passage for channeling a coolant. A foreign object separator includes an arcuate endwall extending from the sidewall, with the core shroud including an intermediate portion spaced from the endwall to define an annular inlet for receiving coolant from the flow passage. The core shroud also includes a distal end spaced from the endwall to define a throat. A separator member has a proximal end joined to the endwall, and a distal end spaced from the core shroud to define an outlet. The distal end of the separator is spaced from its proximal end for allowing the coolant from the throat to impinge against the separator member for turning the coolant prior to discharge from the outlet and using centrifugal force to separate any foreign objects of predetermined size from the coolant. The separated foreign objects are retained adjacent to the separator member proximal end.

Abstract: A reactor core for a gas-cooled reactor, which core is composed of a plurality of prismatic bodies (2) of graphite containing nuclear fuel and having a top wall, a bottom wall and a plurality of vertically extending side walls, each graphite body (2) being provided with a plurality of first coolant flow channels (4) extending vertically between the top wall and the bottom wall, and with a plurality of second coolant flow channels (6) extending transversely to the first channels (4) and each interconnecting a plurality of the first channels (4).

Abstract: Integrated nuclear reactor cooled by a liquid metal and incorporating a main vessel sealed in its upper part by a slab, an inner vessel containing the core, the latter resting on a system for the positioning and supply of the core with liquid metal and which is called the support, the latter itself resting on a supporting structure bearing on the bottom of the main vessel of the reactor, wherein it comprises an inner baffle cladding the side wall and bottom of the main vessel and defining with the latter an intermediate space filled with the liquid metal, tubes for supplying a liquid metal to the intermediate space below the bottom of the main vessel and tubes for returning said liquid metal to an auxiliary exchanger in order to remove heat from the intermediate space.

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.