Abstract: A nuclear plant includes a nuclear reactor, a containment structure that at least partially defines a containment environment of the nuclear reactor, and a passive containment cooling system that causes coolant fluid to flow downwards from a coolant reservoir to a bottom of a coolant channel coupled to the containment structure and rise through the coolant channel toward the coolant reservoir due to absorbing heat from the nuclear reactor. A check valve assembly, in fluid communication with the coolant reservoir, selectively enables one-way flow of a containment fluid from the containment environment to the coolant reservoir, based on a pressure at an inlet being equal to or greater than a threshold magnitude. A fusible plug, in fluid communication with the coolant reservoir at a bottom vertical depth below the bottom of the coolant reservoir, enables coolant fluid to flow into the containment structure based on at least partially melting.

Abstract: Provided are a plurality of embodiments, including, but not limited to, a device for generating efficient low and high average power output Gamma Rays via relativistic particle bombardment of element targets using an efficient particle injector and accelerator at low and high average power levels suitable for element transmutation and power generation with an option for efficient remediation of radioisotope release into any environment. The devices utilize diamond or diamond-like carbon materials and active cooling for improved performance. Also provided are a nuclear reactor and a decontamination device using such a device.

Abstract: A new type of nuclear fuel rods. The rod cladding has an elliptical section transverse to its longitudinal direction and each nuclear fuel pellet has a truncated elliptical shape along the major axis of the cladding, the minor axis of the pellets is the same as the length of the minor axis of the cladding except for the assembly clearance j, the difference in length between the major axis of the cladding and the truncated major axis of the pellets is very much larger than the assembly clearance j. Also disclosed is a method of manufacturing nuclear fuel rods and stacking them in the cladding so as to form a nuclear fuel rod.

Abstract: An embodiment of the present invention takes the form of a system that may reduce the level of flow-induced vibration (FIV) experienced by a jet pump assembly or other similar object within a pressure vessel. Essentially, an embodiment of the present invention may reduce the slip-joint leakage, which may be a cause of the FIVs, by adding a flow-limiting component to an outlet of the slip joint. This component may take the form of a collar, channel, and/or other component that may be connectable to a component of the jet pump assembly. After installation, an embodiment of the present invention may lower the amplitude of, and/or change the frequency of, the FIVs experienced by the jet pump assembly.

Abstract: A nozzle apparatus of a jet pump includes a nozzle base member, and a plurality of nozzles installed to the nozzle base member and forming a plurality of narrowing portions, in which a fluid passage cross-sectional area of a driving fluid passage formed in the nozzle is reduced.

Abstract: The present invention describes a nuclear reactor with a loop for liquid nuclear fuel, which, contrary to similar systems like the Molten-Salt Reactor of the Generation-IV canon, does not use the fuel loop for the heat transport at the same time. Instead, cooling is provided by an additional coolant loop, which is intensively coupled to the nuclear fuel duct for heat transport. That way, the advantages of liquid fuel can be utilized while optimizing the coolant loop performance, so the complexity of safety systems can be reduced significantly. This reactor design further includes an optimized neutron economy and is able to deactivate long-lived fission products generated by its own, so only short-lived radiotoxic waste has to be stored. With the neutron surplus it is also possible to deactivate long-lived radiotoxic waste from used fuel of today's light water reactors or to produce medical radioisotopes.

Abstract: A method for storing the energy of a nuclear power plant in which the nuclear core is cooled by gases or liquid heat transfer media. The hot heat transfer liquid is stored directly in storage tanks. When needed, it is used for heating a power plant. The heat of a compressed gas heat transfer medium such as helium is stored by passing the compressed gas through tanks filled with heat-resistant solids and recovered by passing the same type of gas in a second circuit in a reverse direction. Through the hot tanks to the power plant and back. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Abstract: A jet pump which can restrain self-excited vibration in a connection portion between an inlet mixer pipe and a diffuser pipe without inhibiting a structural deformation due to thermal expansion and the like includes a slip joint structure connecting the inlet mixer pipe and the diffuser pipe to each other by inserting the inlet mixer pipe into an upper end opening of the diffuser pipe with a clearance left therebetween; and a self vibration damping structure configured such that when the clearance defined by an outer pipe wall of the inlet mixer pipe and an inner pipe wall of the diffuser pipe is widening or narrowing due to vibration of the inlet mixer pipe or the diffuser pipe, a flow path resistance inside a clearance flow path for pumped coolant water defined by the clearance is not smaller than a fluid inertia force all over the clearance flow path.

Abstract: According to an embodiment, a pressurized water reactor plant has a primary system which includes: a reactor vessel for housing a reactor core which is cooled by a primary coolant, a single steam generator, a hot leg pipe for connecting the reactor vessel and the steam generator, cold leg pipes, at least two primary coolant pumps, and a pressurizer for pressurizing the primary coolant pressure boundary in which the primary coolant flows. The plant also has: a passive cooling and depressurization system which is a primary depressurization means for equalizing the primary system pressure to the secondary system pressure at the time of a tube rupture accident of the steam generator, and a reactor containment vessel containing the primary system and cooling the primary system by air cooling. Thus, a compact pressurized water rector with high economic efficiency, safety, and reliability can be provided.

Abstract: The present invention relates to a nuclear reactor, in particular a pool-type nuclear reactor cooled with liquid metal (for example, a heavy metal such as lead or lead-bismuth eutectic) or with sodium or molten salts, having a core formed by a bundle of fuel elements and immersed in a primary fluid circulating between the core and at least one heat exchanger; the fuel elements extend along respective parallel longitudinal axes and have respective bottom active parts immersed in the primary fluid to constitute the core, and respective service parts that extend at the top from the active parts and emerge from the primary fluid; the fuel elements are mechanically supported via respective top end heads anchored to supporting structures and can be operated via handling machines.

Abstract: In the boiling water nuclear plant of the present invention, a steam dryer is disposed in a reactor pressure vessel. Materials that have capability of capturing nitrogen compounds containing N-16 are supported on porous member. The porous members are placed in a region where steam goes through in the steam dryer. For example, both or either of perforated plates installed in the steam dryer is constituted of the porous member on which N-16 capture material is supported. When steam containing N-16 goes through the perforated plates, the N-16 is captured by the porous member, whereby the N-16 transfer amount into the turbine system is reduced.

Abstract: A combinatorial heterogeneous-homogeneous reactor configuration in which an array or groups of homogeneous fuel assemblies are interlinked together in a heterogeneous lattice. The present invention removes the limitation of a homogeneous reactor by providing a reactor concept that utilizes the inherent advantages of homogeneous fuel elements but in a heterogeneous fuel lattice arrangement that limits the power density of any one homogeneous fuel element and yet forms a reactor arrangement that is capable of producing any product demand of interest. The present invention provides a method for producing medical isotopes by the use of a modular reactor core comprised of homogeneous fuel assemblies arranged in a regular rectangular or triangular pitch lattice.

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: 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 nuclear reactor (PWNR) includes a core having a containment shield surrounding a reactor vessel having fuel assemblies that contain fuel rods filled with fuel pellets, and control rods, and a steam generator thermally coupled to the reactor vessel. A flow loop includes the steam generator, a turbine, and a condenser, and a pump for circulating a water-based heat transfer fluid in the loop. The heat transfer fluid includes a plurality of nanoparticles having at least one carbon allotrope or related carbon material dispersed therein, such as diamond nanoparticles.

Abstract: This invention relates to a method of preparing nuclear fuel including the step of depositing at least two adjacent series of layers (16, 18) around a kernel (12) of fissile material, each series comprising a layer of pyrolytic carbon (16) contiguous with a layer of silicon carbide (18) and each layer (16, 18) having a thickness of at most (10) micrometers, such that alternate layers of (16, 18) of pyrolytic carbon and silicon carbide are deposited around the kernel (12). The invention extends to a nuclear fuel element (10).

Abstract: A method of storing heat includes moving a portion of a heated fluid from at least one reactor core to at least one tank having solid media, storing heat from the portion of the heated fluid in the solid media, and transferring the stored heat from the solid media to a fluid that can be used by a power plant to generate electrical energy. A system for storing heat in a nuclear power plant includes at least one tank comprising solid media structured and arranged to store heat and an arrangement structured and arranged to pass a first fluid through the at least one tank, transfer heat from the first fluid to the solid media, store the heat in the solid media, and transfer the heat from the solid media to a second fluid. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Abstract: In a cooling structure and a cooling method for a control rod drive mechanism and in a nuclear reactor, a housing (59) in which magnetic jacks are housed is fixed to an upper portion of a reactor vessel (41), and an air intake unit (102) that takes cooling air into the housing (59), a first exhaust duct (104) that is arranged side by side with the air intake unit (102) in a circumferential direction of the housing (59), into which cooling air in the housing (59) is suctioned through a first inlet (109) at a lower portion thereof, and that guides the cooling air upward, a second exhaust duct (105) that is disposed below the air intake unit (102), into which cooling air in the housing (59) is suctioned through a second inlet (110), and that guides the cooling air to the first exhaust duct (104), and a discharging unit (111) that is formed at an upper portion of the housing (59) and discharges cooling air in the first exhaust duct (104) to the exterior are provided.

Abstract: A jet pump has a plurality of nozzles installed to a nozzle base, a throat and a diffuser. A first nozzle straight-tube portion, a first nozzle narrowing portion, a second nozzle straight-tube portion, a second nozzle narrowing portion, and a nozzle lower end portion formed in those nozzles are disposed in this order from the nozzle base to a ejection outlet. A narrowing angle of the second nozzle narrowing portion is larger than of the first nozzle narrowing portion. The jet pump forms, in a lower end portion of the throat, a flow passage narrowing portion having a flow passage cross-sectional area that gradually diminishes. This flow passage narrowing portion is inserted into an upper end portion of the diffuser.

Abstract: Hard stops are useable in an operating nuclear reactor to separate and bias restrainer brackets and inlet mixers. Hard stops include a lip clamp that clamps to a restrainer bracket and a wedge member that biases against the inlet mixer. The wedge member and lip clamp are engaged such that the two components can slide against one another to bias the restrainer bracket and inlet mixer. The lip clamp includes a clamp arm and an engagement member to clamp opposite sides of the restrainer bracket. Ratchet assemblies maintain selective positioning various components of the hard stops. Hard stops may be used in several different numbers, positions, and configurations in repair or modification systems. Hard stops may be installed by determining location on an outside of a restrainer bracket for the hard stop, securing the hard stop at the location, and biasing the hard stop between two components at the location.

Abstract: The geometric dimensions and shape of a device for removing solid particles from the cooling medium that is circulated in the primary circuit of a nuclear reactor, in particular a boiling water nuclear reactor, are such that the device can be inserted in lieu of a fuel element or fuel assembly into an empty fuel element or assembly position of the reactor core of the nuclear reactor.

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: Example embodiments relate to a method and apparatus for reducing electrostatic deposition of charged particles on wetted surfaces that are exposed, periodically or substantially continuously, to high velocity fluid flow within a coolant flow path in a nuclear reactor. The method may include depositing a first or base dielectric layer and a second or outer dielectric layer on a conductive surface that forms a portion of a high velocity flow path to attain the apparatus. The first dielectric layer material is selected to provide improved adhesion and insulation to the conductive surface and the second dielectric layer material is selected to provide suitable adhesion to the first dielectric layer and improved corrosion and/or mechanical resistance in the anticipated operating environment.

Abstract: A natural-circulation type boiling water reactor includes a plurality of divided chimneys provided above a reactor core and a number of fuel assemblies are charged in the reactor core. The natural-circulation type boiling water reactor is provided with a pressure equalization structure arranged on rectangular-columnar lattice plates of the divided chimneys for equalizing pressures in divided chimney portions so as to equalize the pressures of the divided chimneys with the pressure equalization structure.

Abstract: A metal particulate fuel system is described. The metal fuel system may include particulate metal fuel for use in nuclear reactors. The particulate metal fuel may include a plurality of particles of at least one enriched alloy where the particles are compacted into a fuel column. The metal particulate fuel system may also include a cladding and/or a gas-filled plenum.

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: 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: The pressurized water reactor according an embodiment comprises: a cylindrical reactor pressure vessel (1) to which inlet nozzles are connected; fuel assemblies which are contained within the reactor pressure vessel (1); a cylindrical reactor core barrel (3) which surrounds the fuel assemblies and forms an annular downcomer (6) between the reactor core barrel (3) and the inner surface of the reactor pressure vessel (1); and radial supports. The radial supports are supports which are arranged below the downcomer (6) at intervals in the circumferential direction, each has vertical flow path formed therein, and position the reactor core barrel (3) and the reactor pressure vessel (1). The radial supports each has, for example, a flow path-equipped radial keys (21) and a key groove member (40).

Abstract: A boiling water reactor has a core disposed in the reactor pressure vessel and loaded with a plurality of fuel assemblies including transuranic nuclides. A ratio of Pu-239 in all of the transuranic nuclides included in the fuel assembly, which is loaded in the core, with a burnup of 0 is 3% or more but 45% or less. In the fuel assembly having a channel box and a plurality of fuel rods disposed in the channel box, a transverse cross section of a fuel pellet in the fuel rod occupies 30% or more but 55% or less of a transverse cross section of a unit fuel rod lattice in the channel box.

Abstract: A flywheel for a pump, and in particular a flywheel having a number of high density segments for use in a nuclear reactor coolant pump. The flywheel includes an inner member and an outer member. A number of high density segments are provided between the inner and outer members. The high density segments may be formed from a tungsten based alloy. A preselected gap is provided between each of the number of high density segments. The gap accommodates thermal expansion of each of the number of segments and resists the hoop stress effect/keystoning of the segments.

Abstract: A reactor vessel includes a plenum and a reactor core with first and second sets of channels. A blanket salt flows through the first set of channels, and a fuel salt flows through the second set of channels. The plenum receives the blanket salt from the first set of channels. The blanket salt provides a breed-stock for a fission reaction in the fuel salt and transfers heat generated by the fission reaction without mixing with the fuel salt.

Abstract: A dynamic port that extends from the bottom wall of an oil reservoir that surrounds the lower guide bearing of a reactor coolant pump and is in fluid communication within an oil level gauge. The dynamic port is rotatable into and out of the oil flow path to adjust the dynamic oil level shown by the oil level gauge when the pump is at operating speed to be substantially equal to the static oil level when the motor is at rest.

Abstract: A nuclear reactor comprises a nuclear reactor core disposed in a pressure vessel. An isolation valve protects a penetration through the pressure vessel. The isolation valve comprises: a mounting flange connecting with a mating flange of the pressure vessel; a valve seat formed into the mounting flange; and a valve member movable between an open position and a closed position sealing against the valve seat. The valve member is disposed inside the mounting flange or inside the mating flange of the pressure vessel. A biasing member operatively connects to the valve member to bias the valve member towards the open position. The bias keeps the valve member in the open position except when a differential fluid pressure across the isolation valve and directed outward from the pressure vessel exceeds a threshold pressure.

Abstract: A cooling unit cooling a coil assembly that generates electromagnetic force for driving a nuclear reactor control rod, and including a coil surrounding a driving shaft of the nuclear reactor control rod so as to generate the electromagnetic force; a coil housing surrounding the coil so as to enclose the coil; a cooling shroud-shell forming a cooling flow path between the cooling shroud-shell and the coil housing, whereby a cooling fluid for cooling heat that is generated in the coil passes through the cooling flow path; and a plurality of cooling fins disposed on the cooling flow path in a radial direction so as to allow heat to be effectively exchanged between the coil and the cooling fluid that flows through the cooling flow path.

Abstract: A jet pump sensing line support clamp may be used for sensing line repair, replacement, and damage prevention or reduction. The clamp may affix to jet pump sensing line supports and confine the individual jet pump sensing lines. The clamp may provide for further access or securing of the lines in the support through the clamp. Methods of installing the clamp may include attaching and tightening the clamp against the sensing lines.

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 hold-down spring unit for a top nozzle of a nuclear fuel assembly. The hold-down spring unit is coupled to the upper end of the top nozzle of the nuclear fuel assembly. The hold-down spring unit includes a first spring which provides a hold-down force upon the nuclear fuel assembly under start-up conditions or hot full power conditions of a nuclear reactor, and a second spring which provides an additional hold-down force upon the nuclear fuel assembly under start-up conditions of the nuclear reactor. The hold-down margin under start-up conditions or hot full power conditions is reduced, thus enhancing the mechanical and structural stability of the nuclear fuel assembly.

Abstract: A nuclear reactor module includes a reactor core and a reactor housing that surrounds the reactor core about its sides, wherein the reactor housing is configured to direct coolant through the reactor core. A neutron reflector is located between the reactor core and the reactor housing, wherein the neutron reflector has a plurality of inlet ports facing the reactor core. The neutron reflector also has a plurality of outlet ports fluidly connected to the inlet ports to direct a portion of the coolant through the neutron reflector.

Abstract: A nozzle apparatus of a jet pump includes a nozzle base member, and a plurality of nozzles installed to the nozzle base member and forming a plurality of narrowing portions, in which a fluid passage cross-sectional area of a driving fluid passage formed in the nozzle is reduced.

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 method of predicting stresses on a BWR steam dryer that includes creating an analytical acoustic model of a BWR steam system; generating pressure estimations by inputting empirical data into the analytical acoustic model of the BWR steam system; creating an analytical structural model of the BWR steam dryer; and predicting stresses on the BWR steam dryer using the analytical structural model and the pressure estimations.

Abstract: A pressurized water reactor (PWR) includes a vertical cylindrical pressure vessel having a lower portion containing a nuclear reactor core and a vessel head defining an integral pressurizer. A reactor coolant pump (RCP) mounted on the vessel head includes an impeller inside the pressure vessel, a pump motor outside the pressure vessel, and a vertical drive shaft connecting the motor and impeller. The drive shaft does not pass through the integral pressurizer. The drive shaft passes through a vessel penetration of the pressure vessel that is at least large enough for the impeller to pass through.

Abstract: An embodiment of the present invention provides an apparatus and system for repairing and/or maintaining a position of a first component in relation to a second component. The first and second components may be located within a reactor pressure vessel of a nuclear powerplant. The apparatus and system may attach at least one bearing plate to a horizontal surface of the first component. The apparatus and system includes structure to apply a pre-load to the first component. This may assist in maintaining the position of the first component relative to the second component.

Abstract: After an inner wall tube, made of steel or alloy containing not less than 2% of Cr, whose outer surface thereof is machined and/or ground to a thickness of 0.1 mm or more including the scale layer, is inserted into an outer wall tube, made of ferritic steel containing not less than 2% of Cr, in which an oxide scale layer containing Cr and having a thickness of 10 to 30 ?m is formed in the inner surface thereof , cold working at an outside diameter reduction rate of 5 to 30% is performed. Similarly cold worked after an inner wall tube having an oxide scale layer on the outer surface thereof, is inserted into an outer wall tube whose inner surface is machined and ground. A double-walled tube made has a uniform gap and an excellent thermal conductivity, and is suitable as materials for SG tubes of future FBR.

Abstract: An embodiment of the present invention takes the form of an apparatus or system that may reduce the level of vibration experienced by an inlet riser or other similar object within a reactor pressure vessel. An embodiment of the present invention may eliminate the need for welding the riser brace to the inlet riser. An embodiment of the present invention provides at least one riser brace clamp that generally clamps the riser brace to the inlet riser. After installation, the riser brace clamp may lower the amplitude of, and/or change the frequency of, the vibration experienced by the inlet riser.

Abstract: A treatment of a heater tube intended to be used in a pressurizer of the primary cooling system of a nuclear reactor. In particular, the heater tube comprises a heater housed in a substantially cylindrical sheath. The material of which this sheath is made is a work-hardened austenitic stainless steel. In particular, the external surface of the sheath is liable to undergo a stress corrosion during use of the heatertube. The method includes a heat treatment step, preferably using induction heating, in which the external surface of the sheath is heat-treated so as to recrystallize the material of the sheath at least on the surface thereof.

Abstract: An electromagnet comprises a plurality of nested freestanding electrically insulating former layers, and electrically conductive wire wrapped around the outsides of the freestanding electrically insulating former layers to define a multilayer electrical coil in which adjacent layers of the multilayer electrical coil are spaced apart by intervening freestanding electrically insulating former layers. Electrically energizing the multilayer electrical coil generates a magnetic field inside the multilayer electrical coil. In some embodiments the electrically conductive wire is bare wire not having electrical insulation. In some embodiments the former layers comprise a ceramic material. In some such embodiments the electromagnet further comprises a ferromagnetic core disposed inside the multilayer electrical coil. An electric motor employing such an electromagnet as a stator pole is also disclosed.

Abstract: A jet pump comprising: a nozzle apparatus having a header portion including, inside, a first pipe member forming a suction fluid passage for introducing suction fluid and the header portion surrounding the first pipe member, for introducing driving fluid, and a nozzle portion connected to the header portion, surrounding the first pipe member and forming an annular ejection outlet for ejecting the driving fluid; a jet pump body for mixing the driving fluid and the suction fluid sucked by the ejection of the driving fluid, and discharging the mixed fluid; and a second pipe member having one end connected to the nozzle apparatus, for introducing the driving fluid to the header portion, wherein the first pipe member is disposed through the one end inside a driving fluid passage formed in the second pipe member, and forms an opening portion of the suction fluid passage opened to the outside of the second pipe member; and the driving fluid passage is formed so that the driving fluid flowing toward the one end hi