Abstract: A nuclear power plant with an improved cooling system using nanoparticles in solid or fluid form is provided. The nanoparticles are delivered in locations such as the cold leg accumulator and high and low pressure pumps of an emergency core cooling system. Motor driven valves and pressurization can aid in the delivery. Methods for providing the nanoparticles are also provided.

Abstract: A method and apparatus for providing an alternative remote spent fuel pool cooling system for the spent fuel pool. The cooling system is operated to cool the spent fuel pool in the event of a plant accident when normal plant electricity is not available for the conventional fuel pool cooling and cleanup system, or when the integrity of the spent fuel has been jeopardized. The cooling system is operated and controlled from a remote location, which is ideal during a plant emergency.

Abstract: Filtering systems and methods remove debris from coolant in a nuclear reactor setting. One or more filters are installed outside coolant reservoirs specifically where coolant will flow toward the reservoir, such as during a transient or other coolant leak event. Useable filters permit coolant through-flow while catching, straining, diverting, or otherwise removing debris from the coolant without significant interference with the coolant flow. Filters can be installed at any location in a flow path for coolant flowing toward the reservoir, including pipes draining into a suppression pool, floor or personnel platform gratings, areas around main steam legs or steam generators, in a reactor drywell, etc. One or more filters are installed by securing the filter in a coolant flow path into a coolant source. Installation and maintenance can be performed during any maintenance period.

Abstract: A method and apparatus for providing an alternative remote spent fuel pool cooling system for the spent fuel pool. The cooling system is operated to cool the spent fuel pool in the event of a plant accident when normal plant electricity is not available for the conventional fuel pool cooling and cleanup system, or when the integrity of the spent fuel has been jeopardized. The cooling system is operated and controlled from a remote location, which is ideal during a plant emergency.

Abstract: A nuclear power plant includes a nuclear reactor containment structure housing a nuclear reactor, a pressure vessel containing condensed water therein and having a receiving space located lower than a bottom of the containment structure, a release pipe connecting the containment structure to the pressure vessel such that water vapor and fission products generated in the containment structure in the event of an accident is capable of flowing into the pressure vessel, and a recovery pipe connecting the pressure vessel to the containment structure such that the condensed water received in the pressure vessel is capable of flowing into the containment structure. When a level of the condensed water received in the pressure vessel is higher than a water level in the containment structure, the condensed water flows from the pressure vessel toward the containment structure by a water head difference.

Abstract: The present disclosure provides a cooling system of an emergency cooling tank, which enables long-term cooling without refilling cooling water, in case of the change in a quantity of heat transferred to the emergency cooling tank according to a lapse of time upon an occurrence of an accident of a nuclear reactor, and a nuclear power plant having the same.

Abstract: Provided is a passive containment spray system including: a spray coolant storage unit that communicates with a containment accommodating a reactor vessel and maintains equilibrium of pressure between the spray coolant storage unit and the containment; a spray pipe that is installed within the containment in such a manner that when an accident occurs, a coolant supplied from the spray coolant storage unit is sprayed into the containment through the spray pipe due to an increase in pressure within the containment; and a connection pipe one end of which is inserted into the spray coolant storage unit in such a manner as to provide a flow path along which the coolant flows and the other end of which is connected to the spray pipe in such a manner that the coolant is passively supplied to the spray pipe through the connection pipe therein.

Abstract: The module according to the invention includes means in the form of an elongated cylindrical box (12) in which means are integrated forming an electricity production unit including means forming a nuclear boiler (30), associated with electricity production means (37) connected to an external electricity distribution station by electrical cables, is wherein the nuclear boiler-forming means (30) are placed in a dry chamber (19) of the reactor compartment (18) associated with the chamber forming a safety water storage reservoir (20) of the reactor whereof at least the radial wall (53) is in a heat exchange relationship with the marine environment and in that the nuclear boiler-forming means (30) include a reactor container (32), placed in a reactor pit (90) whereof the lower portion is connected to the lower portion of the safety water storage reservoir chamber (20) of the reactor through means forming a water inlet duct (91) placed along the radial wall (53) of the module (12) and whereof the upper portion is c

Abstract: A high capacity suction strainer for a nuclear reactor has a frame, a flow-through plenum, and a filter array. The flow-through plenum is mechanically mounted to the frame and has a plurality of inlets and an outlet. The filter array is also mechanically mounted to the frame and has a plurality of filter groupings in fluid communication with the inlet on the plenum.

Abstract: The module according to the invention includes means in the form of an elongated cylindrical box (12) in which means are integrated forming an electricity production unit including means forming a nuclear boiler (30), associated with electricity production means (37) connected to an external electricity distribution station (7) by electrical cables (6), is characterized in that the nuclear boiler-forming means (30) are placed in a dry chamber (19) of the reactor compartment (18) associated with the chamber forming a safety water storage reservoir (20) of the reactor whereof at least the radial wall (53) is in a heat exchange relationship with the marine environment and in that the dry chamber (19) of the reactor compartment is associated with a compartment (21) receiving electricity production means (37), and in that the latter includes means (100) for introducing quenching water of the dry chamber (19) receiving the reactor, placed in its lower portion and including a seawater inlet (101) formed in the radia

Abstract: A liquid metal cooled nuclear reactor includes a reactor vessel, a containment, an air flow path, and an injection unit. The vessel has a reactor core and a coolant for the reactor core. The containment surrounds an outside of the vessel. The air flow path removes heat by flowing air around the containment. The injection unit injects filler in a gap between the vessel and the containment.

Abstract: A nuclear reactor includes a reactor vessel, a containment vessel that surrounds the reactor vessel, and a condenser that receives coolant from within the reactor vessel. The containment vessel and the condenser are at least partially submerged within a common reactor pool of liquid.

Abstract: A nuclear reactor includes a pressure vessel and a nuclear reactor core disposed in the pressure vessel. A subterranean containment structure contains the nuclear reactor. An ultimate heat sink (UHS) pool is disposed at grade level, and an upper portion of the subterranean containment structure defines at least a portion of the bottom of the UHS pool. In some embodiments, the upper portion of the subterranean containment structure comprises an upper dome, which may protrude above the surface of the UHS pool to define an island surrounded by the UHS pool. In some embodiments, a condenser comprising a heat exchanger including hot and cold flow paths is disposed inside the subterranean containment structure; and cooling water lines operatively connect the condenser with the UHS pool.

Abstract: The present invention relates to an alternate feedwater injection system to at least partially mitigate the effects of an aircraft impact on a light water nuclear reactor positioned in a reactor building. The light water nuclear reactor has a primary system and a reactor core. The alternate feedwater injection system includes a water storage tank, an injection point into the primary system, a pump capable to transfer water from the water storage tank to the injection point and ultimately to the reactor core. The water storage tank and pump are located external to a reactor building and outside of an identified aircraft impact area or inside the identified aircraft impact area and provided with a means of protection from the aircraft impact.

Abstract: A nuclear reactor comprises a pressure vessel containing a nuclear reactor core. A reactor core cooling system comprises a standpipe including a plurality of orifices in fluid communication with a refueling water storage tank (RWST) to drain water from the RWST into the standpipe, and an injection line configured to drain water from the standpipe to the pressure vessel. In some embodiments the standpipe is disposed in the RWST, while in other embodiments the standpipe is disposed outside of the RWST and cross-connection pipes connect the plurality of orifices with the RWST. The reactor core cooling system may further comprise a valve configured to control flow through one orifice of the plurality of orifices in fluid communication with the RWST based on water level in the standpipe. The valve may comprise a float valve having its float disposed in the standpipe.

Abstract: Heat from an ex-vessel mass of core material is removed to cooler regions of a containment envelope via liquid and/or vapor phase transport. Various aspects provide for contacting the ex-vessel core material with a material having properties including melting point, boiling point, and condensation kinetics such that condensation of the material in cooler regions of the containment envelope is at least as fast as evaporation of the material due to heat absorption from the core material and associated species.

Abstract: A nuclear reactor module includes a reactor vessel and a reactor housing mounted inside the reactor vessel, wherein the reactor housing comprises a shroud and a riser located above the shroud. The nuclear reactor module further includes a heat exchanger proximately located about the riser, and a reactor core located in the shroud. A steam generator by-pass system is configured to provide an auxiliary flow path of primary coolant to the reactor core to augment a primary flow path of the primary coolant out of the riser and into the shroud, wherein the auxiliary flow path of primary coolant exits the reactor housing without passing by the heat exchanger.

Abstract: The present disclosure may disclose a multi stage safety injection device and a passive safety injection system having the same, including a safety injection tank formed to contain coolant to be injected into a reactor vessel by a gravitational head of water when an accident occurs in which the pressure or water level of the reactor vessel is decreased, a pressure balance line connected to the reactor vessel and safety injection tank to form a pressure balance state between the reactor vessel and the safety injection tank, a safety injection line connected to a lower end portion of the safety injection tank and the reactor vessel to inject coolant to the reactor vessel in a pressure balance state between the reactor vessel and the safety injection tank, and a flow control line extended from the safety injection line to an inner portion of the safety injection tank, and provided with safety injection ports into which coolant is injected at predetermined heights, respectively, to reduce the flow rate of coolant

Abstract: The present disclosure may disclose a multi stage safety injection device, including a safety injection tank formed to contain coolant to be injected into a reactor vessel by a gravitational head of water when an accident occurs in which the pressure or water level of the reactor vessel is decreased, a pressure balance line connected to the reactor vessel and safety injection tank to form a pressure balance between the reactor vessel and the safety injection tank, and a set of safety injection lines connected to the safety injection tank and the reactor vessel to inject coolant to the reactor vessel in a pressure balance state between the reactor vessel and the safety injection tank, and connected to the safety injection tank with different heights to reduce a flow rate of coolant injected into the reactor vessel step by step according to the water level reduction of the safety injection tank in order to inject coolant to the reactor vessel at multi stages.

Abstract: A system for passively cooling nuclear fuel in a pressurized water reactor during refueling that employs gravity and alignment of valves using battery reserves or fail in a safe position configurations to maintain the water above the reactor core during reactor disassembly and refueling. A large reserve of water is maintained above the elevation of and in fluid communication with the spent fuel pool and is used to remove decay heat from the reactor core after the reaction within the core has been successfully stopped. Decay heat is removed by boiling this large reserve of water, which will enable the plant to maintain a safe shutdown condition without outside support for many days.

Abstract: A passive cooling system for a reactor core of a large-scale pressurized water reactor nuclear power plant includes a shield building having an outer wall and a through air inlet arranged on an upper part of the outer wall, a water tank arranged at an upper part of the shield building, a cooling water distribution plate arranged above a top of a containment within the shield building, a spray pipe arranged at an inside of the top of the shield building and having a water inlet end and a water outlet end, wherein the water inlet end is connected to a bottom of the water tank and the water outlet end is extended to be above the cooling water distribution plate, and an air deflector arranged between the shield building and the containment and having an upper end connected to an inside of the top of the shield building.

Abstract: The invention includes a heat exchanger provided at a position higher than a primary containment vessel; a condensate storage tank disposed below the heat exchanger and above an upper end of a reactor core placed in a reactor pressure vessel; a non-condensate gas discharge line connected to an upper section of the condensate storage tank and to a suppression pool; a second condensate discharge line connected to a position below that section of the condensate storage tank to which a first end of the non-condensate gas discharge line is connected, and to the suppression pool; and a condensate return line connected to a position below that section of the condensate storage tank to which a first end of the second condensate discharge line is connected, and to a side portion of the reactor pressure vessel, the side portion being above the upper end of the core.

Abstract: An embodiment uses liquid nitrogen, the densest and highly transportable form of nitrogen, and the cold nitrogen gas it produces when released from its container, for emergency cooling of fuel rods and nuclear reaction chambers.

Abstract: The invention relates to a method and an arrangement for providing an emergency supply to a nuclear installation. The arrangement comprises a container (10) with a plurality of permanently installed devices and at least one motor (22), one generator (26), one pump (24), one fuel tank (14) and one transformer (34), wherein the pump and the generator are functionally connected to the motor in order to activate said motor.

Abstract: A nuclear reactor is provided that includes a core with nuclear fuel assemblies; a circuit for cooling the core in which circulates a fluid coolant; and a device provided for injecting nanoparticles into the fluid coolant. The nanoparticles include first nanoparticles of a first type having a first form factor of less than two, and second nanoparticles of a second type different from the first type having a second form factor greater than two, the nanoparticles comprising between 10% and 90% by weight of the first nanoparticles and between 90% and 10% by weight of the second nanoparticles.

Abstract: A support clamp assembly for mechanically securing a thermal sleeve to an elbow conduit in a jet pump of a nuclear reactor vessel, the support clamp assembly including: a tension shaft having a first end extendable through an opening in a sidewall of the elbow conduit and an opposite end with a head; a cruciform assembly having a base with an opening to receive the tension shaft and to abut the head of the shaft, wherein the cruciform assembly seats in the thermal sleeve; a boss slidable over the first end of the tension shaft and having a curved surface seating an outside surface of the elbow conduit, and a coupling device engaging the first end of the tension shaft and abutting the boss, wherein the coupling device places the tension shaft under tension to secure the cruciform assembly to the thermal sleeve and the boss to the elbow conduit.

Abstract: A strainer wall structure includes curved sections, a method of manufacturing the same, and a filtering method using the strainer wall structure to provide a substantially larger effective filtering area in the same length and width, substantially reducing foreign substances covering a suction surface and flow resistance of the foreign substances, and reducing pressure drop at a cooling water pass corresponding thereto. The strainer wall structure includes an inlet side through which cooling water is introduced and an outlet side through which the filtered cooling water is discharged, includes a body having openings in directions of the inlet side and the outlet side, and a first filter plate inserted into the body and including curved sections formed by alternately bending a first punched plate having filtering holes in opposite directions and at a predetermined interval.

Abstract: A separate type safety injection tank comprises: a coolant injection unit connected to a reactor coolant system by a safety injection pipe such that coolant stored therein is injected into the reactor coolant system by a pressure difference from the reactor coolant system when a loss-of-coolant-accident (LOCA) occurs; a gas injection unit connected to the coolant injection unit, and configured to pressurize the coolant injected into the reactor coolant system, by introducing gas stored therein to an upper part of the coolant injection unit in the loss-of-coolant-accident; and a choking device disposed between the coolant injection unit and the gas injection unit, and configured to contract a flow cross-sectional area of the gas introduced to the coolant injection unit, and configured to maintain a flow velocity and a flow rate of the gas introduced to the coolant injection unit as a critical flow velocity and a critical flow rate when a pressure difference between the coolant injection unit and the gas inject

Abstract: A pressurized water nuclear reactor (PWR) has an internal pressurizer volume containing a steam bubble and is surrounded by a containment structure. A condenser is disposed inside the containment structure and is operatively connected with an external heat sink disposed outside of the containment structure. A valve assembly operatively connects the PWR with the condenser responsive to an abnormal operation signal such that the condenser condenses steam from the steam bubble while rejecting heat to the external heat sink and returns the condensed water to the PWR. A quench tank contains water with dissolved neutron poison. A valved tank pressurizing path selectively connects the steam bubble to the quench tank to pressurize the quench tank, and a valved soluble poison delivery path selectively connects the quench tank to the PWR such that the quench tank under pressure from the steam bubble discharges water with dissolved neutron poison into the PWR.

Abstract: A passive safety system includes a containment, a reactor in the containment, a plurality of safety injection tanks connected with the reactor and having water and nitrogen gas to supply water thereof into the reactor through a safety injection line communicating to the first safety injection line upon a loss of coolant accident, a plurality of core makeup tanks connected with the reactor to supply water thereof into the reactor through a second safety injection line communicating to a safety injection line upon the loss of coolant accident, and a plurality of passive residual heat removal systems to remove residual heat from the reactor upon the loss of coolant accident or a non-loss of coolant accident. The water in each of the safety injection tank is stably supplied to the reactor for many hours by a differential head resulting from gravity or gas pressure.

Abstract: A passive safety injection system includes a containment, a reactor installed in the containment, safety injection tanks installed in the containment, a safety injection line between the reactor or a reactor coolant system and each of the safety injection tanks to guide water, which is stored in the safety injection tank, into the reactor when a water level in the reactor is reduced due to a loss of coolant accident, and a pressure balance line between the reactor or the reactor coolant system and the safety injection tank to guide high-temperature steam from the reactor into the safety injection tank upon the loss of coolant accident. The safety injection line has an orifice and a check valve thereon, and the pressure balance line has an orifice and isolation valves thereon. The water in the safety injection tank stably flows into the reactor for many hours.

Abstract: The present invention relates to a longitudinally divided emergency core cooling (ECC) duct in order to efficiently inject safety water to core of a pressurized light-water nuclear reactor. The ECC duct includes side supports for preventing the flow-induced vibration in the annular downcomer, and has structural stability while thermally expanding and contracting. A longitudinally divided ECC duct for emergency core cooling water injection of a nuclear reactor is provided on the periphery of a core barrel of a nuclear reactor, includes an emergency core cooling water inlet facing a direct vessel injection nozzle, and extends in a longitudinal direction of the core barrel. The longitudinally divided ECC duct is divided into a plurality of longitudinally-divided ducts in the longitudinal direction of the longitudinally divided ECC duct.

Abstract: According to an embodiment, a nuclear power plant has a core; a reactor pressure vessel; a dry well; a wet well; a vacuum breaker; a containment vessel including the dry well, the LOCA vent pipe, the wet well, and the vacuum breaker; a cooling water pool placed outside the containment vessel; a heat exchanger at least partially submerged in cooling water; a gas supply pipe connected to the inlet plenum of the heat exchanger and the dry well; a condensate return pipe connected to the outlet plenum of the heat exchanger and the containment vessel; and a gas vent pipe connected to the outlet plenum of the heat exchanger and an outside of the wet well so that non-condensable gas inside the heat exchanger is released out of the wet well. The gas vent pipe is not connected to the wet well.

Abstract: An integral pressurized water reactor that combines all of the components typically associated with a nuclear steam supply system, such as the steam generator, reactor coolant pumps, pressurizer and the reactor, into a single reactor pressure vessel. The reactor pressure vessel is itself enclosed in a containment pressure vessel that also houses a number of safety systems, such as the core make-up tanks, the primary side of residual heat removal heat exchangers, an automatic depressurization system and a recirculation system that enables continuous core cooling through natural circulation over an extended period of time. Actuation of the passive systems is done by single actuation of valves, powered from redundant batteries.

Abstract: A combined makeup tank and passive residual heat removal system that places a tube and shell heat exchanger within the core makeup tank. An intake to the tube side of the heat exchanger is connected to the hot leg of the reactor core and the outlet of the tube side is connected to the cold leg of the reactor core. The shell side of the heat exchanger is connected to a separate heat sink through a second heat exchanger.

Abstract: A mechanical connection between adjacent components of a system may include a first component of the system, a second component of the system, and a multiple degree-of-freedom connection between the first and second components. The multiple degree-of-freedom connection may have at least four degrees of freedom. A method for establishing a mechanical connection between adjacent components of a system may include disposing a first component of the system adjacent to a second component of the system, and connecting the first component to the second component using a multiple degree-of-freedom connection. The multiple degree-of-freedom connection may have at least four degrees of freedom.

Abstract: A nuclear reactor includes a nuclear reactor core disposed in a pressure vessel and immersed in primary coolant water at an operating pressure higher than atmospheric pressure. A containment structure contains the nuclear reactor. A reactor coolant inventory and purification system (RCI) is connected with the pressure vessel by make-up and letdown lines. The RCI includes a high pressure heat exchanger configured to operate responsive to a safety event at the operating pressure to remove heat from the primary coolant water in the pressure vessel. An auxiliary condenser located outside containment also removes heat. The RCI also includes a pump configured to inject make up water into the pressure vessel via the make-up line against the operating pressure. An emergency core cooling system (ECC) operates to depressurize the nuclear reactor only if the RCI and auxiliary condenser are unable to manage the safety event.

Abstract: A novel heat exchanger (FIG. 1) designed and fabricated based on dry ice-ethylene glycol (DIEG) bath 1 as the coolant mixture for the emergency core cooling system (ECCS) of the nuclear power systems to avoid core meltdown during the normal reactor shutdown or reactor scram in the emergency conditions. This method is proposed to upgrade the safety systems including modified ECCS which utilizes fast non-water coolant emergency system by fast cooling of reactor pressure vessel (RPV) 31 based on dry ice+ethylene glycol slurry 1.

Abstract: A nuclear reactor includes an internal steam generator and a nuclear core disposed in a containment structure. A condenser is disposed outside the containment structure, and includes a condenser inlet line tapping off a steam line connected to the steam generator outside the containment structure, and a condensate injection line conveying condensate from the condenser to the integral steam generator. Isolation valves are located outside the containment structure on a feedwater line, the steam line, and the condensate injection line. The valves have an operating configuration in which the isolation valves on the feedwater and steam lines are open and the isolation valve on the condensate injection line is closed, and a heat removal configuration in which the isolation valves on the feedwater and steam lines are closed and the isolation valve on the condensate injection line is open.

Abstract: A passive cooling and depressurization system for a pressurized water nuclear plant is provided with a cooling water pool, a steam supply piping, a heat exchanger, a steam supply valve, a coolant return pipe and an outlet valve. The steam supply piping extends from the gas phase of the pressurizer. The heat exchanger exchanges heat between water stored in the cooling water pool and steam flowing through the steam supply piping. The steam supply valve is equipped on the steam supply piping. The coolant return pipe extends from the heat exchanger to a liquid phase of the reactor pressure boundary. The outlet valve is equipped on the coolant return pipe.

Abstract: A blocking device for preventing the actuation of an automatic depressurization system in a pressurized nuclear reactor system due to spurious signals resulting from a software failure. The blocking signal is removed when the coolant level within the core makeup tanks drop below a predetermined level.

Abstract: A nuclear reactor module includes a reactor vessel and a reactor housing mounted inside the reactor vessel, wherein the reactor housing comprises a shroud and a riser located above the shroud. The nuclear reactor module further includes a heat exchanger proximately located about the riser, and a reactor core located in the shroud. A steam generator by-pass system is configured to provide an auxiliary flow path of primary coolant to the reactor core to augment a primary flow path of the primary coolant out of the riser and into the shroud, wherein the auxiliary flow path of primary coolant exits the reactor housing without passing by the heat exchanger.

Abstract: A supplementary injection device is installed in a nuclear power plant to draw coolant and inject coolant using an entraining fluid. The injection device can be a venturi or other passive device operable at relatively low fluid pressure that draws coolant through suction at the venturi narrowing point and mixes the coolant with the fluid for injection. The injection device is operable with a known BWR design, where the device is attached to a steam connection to the main steam line of the reactor, a coolant connection drawing from suction lines to a suppression cool or condensate tank, and an outlet connection injecting into the main feedwater lines. In a BWR, the injection device is operable without electricity and at a wide range of pressures, even less than 50 pounds per square inch, to maintain coolant levels in the reactor.

Abstract: A drain sump of a reactor containment vessel having a containment vessel floor down below a reactor pressure vessel, and includes a heat-proof sump cover and two or more drain flow paths. The drain sump is arranged inside the containment vessel floor. The heat-proof sump cover has a thickness, and covers an upper part of the drain sump. The thickness allows a top surface of the sump cover to lie in the same surface as a top surface of the containment vessel floor. The drain flow paths pass through the sump cover in a thickness direction to flow water therethrough and solidify a molten corium therein. The molten corium is produced in the unlikely event of a severe accident.

Abstract: An emergency core cooling system is provided with at least four active safety divisions each equipped with a motor-driven active safety system, and at least one passive safety division equipped with passive system that does not require to be electrically driven. The number of active safety divisions is grater than the number of active safety divisions needed during a design basis accident by two or more, and each active safety division is provided with one motor-driven active safety system. The passive safety system can cool the reactor core without being re-supplied with cooling water from the outside during the time period needed for the active safety system subjected to online maintenance to recover if an accident occurred during online maintenance of one active safety system.

Abstract: When a power source is lost after an operation stop of a nuclear power plant, a first open/close valve is opened via a first battery at an early stage and steam in a reactor pressure vessel (RPV) is condensed in a suppression pool. The heat of the water in the suppression pool is transmitted to a cooling water pool located below inner space between first and second reactor containment vessels surrounding the RPV. A second open/close valve is opened via a second battery at the early stage and cooling water in a tank is injected into the RPV. After the early stage, a third open/close valve is opened via a third battery, and a cooling medium becomes steam by an evaporator in the RPV, the steam being condensed by a condenser disposed in the inner space to become a liquid of the cooling medium and is returned to the evaporator.

Abstract: The Liquid Nitrogen Cooling System utilizes a continuously recharged, closed-loop system to: generate electricity; charge and pressurize hydraulic bypass and operational equipment; and, provide emergency cooling. It is triggered by any need for emergency shutdown, applying liquid Nitrogen to cool a nuclear power plant, as an alternate cooling system independently from the regular cooling system, providing a sudden drop of temperature through a liquid Nitrogen manifold system. No greenhouse or explosive gases are generated or released, and no Oxygen is used. Any Nitrogen vented to the atmosphere dissipates rapidly, assumes ambient temperature, and has no long half-life radioactive isotopes. It operates as a closed/static system until needed for cooling. Applications include, but are not limited to, retrofitting to existing systems.

Abstract: An assembly is provided including a mobile structure including a main pipe equipped with a first end intended to be connected to a water supply and a second end intended to be connected to a circuit connected to the primary circuit of the reactor, and including between these two ends in the direction of circulation of the water, a pump, a water heating device, an injector for continuously injecting the powdered neutron-absorbing element into the water of the main pipe, a first mixer for mixing and dissolving powder with water and a controller driving and controlling the flow rate of the water and the flow rate of the powder injected.

Abstract: A strainer wall structure that removes foreign substances from a fluid suctioned into a pipe and a re-circulation pump that is part of an emergency core cooling system (ECCS). The strainer wall structure has an inlet side and an outlet side through which cooling water is introduced and discharged, respectively, and includes a body having an opening in a direction of the inlet side, closed side surfaces, and an outlet port disposed at one of the closed side surfaces. The strainer includes a punched plate filter screen inserted into the opening. A modular cassette apparatus including grooved first filter plates is inserted into the body, and second filter plates having second grooves is inserted into the first grooves.

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.