A clevis type slip hook or grab hook includes a safety latch which is held in position by a biased pin that may be axially extended to move the latch between a latching and unlatching position to close or open the slot in the slip hook. The latch is comprised of a closure member in the form of a plate having an elongate edge that fits in the hook slot between the tip end and shank end of the hook.

A clamp for a tensile implement and method of clamping a tensile implement is disclosed. The clamp is portable and adaptable to different sizes of tensile implements. The clamp includes a cavity defined by side surfaces of a pair of blocks which are attached to a top surface of a grip base. A pair of mated reciprocal wedges, selected based on size of the tensile implement from a plurality of pairs of wedges, fits and slides within the cavity in order to grip the tensile implement. Each one of the wedges has a planar surface for sliding and a semi-cylindrical void which forms a cylindrical void through which the tensile implement passes when fully clamped around the tensile implement.

A jointed mechanism including a segment coupled to a joint; and an elongated component coupled to the segment, where applying a pulling force to the elongated component rotates the segment around the joint, elastically deforming the elongated component; wherein the elastic deformation generates an elongated component elastic force sufficient to rotate the segment, in an opposite direction, in absence of the pulling force.

A vacuum-lifting device includes a holding block and a nozzle. The holding block defines a holding hole and a threaded hole communicating with the holding hole. The nozzle includes a first section that is slidably received in the holding hole and a second section. The second section extends from the first section and has an outer diameter smaller than an outer diameter of the first section.

A zirconium alloy nuclear reactor cylindrical cladding has an inner Zr substrate surface (10), an outer volume of protective material (22), and an integrated middle volume (20) of zirconium oxide, zirconium and protective material, where the protective material is applied by impaction at a velocity greater than 340 meters/second to provide the integrated middle volume (20) resulting in structural integrity for the cladding.

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

According to an installation method of a water-chamber working apparatus of the present invention, the water-chamber working apparatus includes a base that holds heat transfer tubes on a tube plate surface and is fixed to the tube plate surface, and a manipulator that is coupled with the base, suspended in a water chamber and arranged therein, and has a separable configuration. In this case, a base installing step of installing the base on the tube plate surface and a manipulator coupling step of carrying the separated manipulator (a front stage and a rear stage) into the water chamber sequentially and individually and coupling the manipulator with the base (a coupling link) are performed.

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.

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.

Systems and methods for operating an accelerator driven sub-critical core. In one embodiment, a fission power generator includes a sub-critical core and a plurality of proton beam generators. Each of the proton beam generators is configured to concurrently provide a proton beam into a different area of the sub-critical core. Each proton beam scatters neutrons within the sub-critical core. The plurality of proton beam generators provides aggregate power to the sub-critical core, via the proton beams, to scatter neutrons sufficient to initiate fission in the sub-critical core.

A method and apparatus for repairing and/or reinforcing a Boiling Water Reactor (BWR) jet pump riser pipe. The repair includes attaching two collars to the riser pipe using match drilling to drill holes through the collars and the riser pipe and plugging the holes with expandable plugs. Support columns are attached to the collars. Brace supports are slideably attached to the support columns. Gaps between each brace support and its respective collar are then narrowed as ratchet bolts may apply a force that pulls downward on an upper collar and pulls upward on a lower collar, thereby exerting a compression force on the riser pipe. A clamp assembly may also be located between the two collars that applies a hoop force on the riser pipe.

Textured surface for increasing Leidenfrost temperature. The texture comprises of surface features over multiple length scales—from micro to nanoscale—wherein the features at each length scale have a size, aspect ratio, and spacing selected to increase the Leidenfrost temperature. The structure includes an array of microscale structures disposed on the surface, the structure having size, aspect ratio and spacing selected to increase Leidenfrost temperature. The microscale structures may also include nanoscale structures on their surface to create a hierarchical structure. The structures result in an increased Leidenfrost temperature.

An apparatus for monitoring nuclear thermal hydraulic stability of a nuclear reactor, contains: a calculation unit configured to calculate a stability index of a nuclear thermal hydraulic phenomenon based on nuclear instrumentation signals, the signals being outputted by a plurality of nuclear instrumentation detectors placed at regular intervals in a reactor core; a simulation unit configured to simulate the nuclear thermal hydraulic phenomenon based on a physical model by using information on an operating state of the nuclear reactor as an input condition; a limit value updating unit configured to update a limit value of the nuclear thermal hydraulic phenomenon based on a result of the simulation; and a determination unit configured to determine, based on the stability index and the limit value, whether or not to activate a power oscillation suppressing device.

An aneutronic magnetron energy generator that generates microwave energy from a fusion-fission reaction that produces alpha particles in response to a proton colliding with an 11B nucleus. The magnetron energy generator includes a magnetron having an anode resonator including a central chamber and a plurality of radially disposed cavities. A cathode assembly is provided at the center of the chamber and includes a cathode electrode that generates a proton plasma. A series of electrically isolated acceleration rings extend from the cathode electrode and operate to accelerate protons from the proton plasma towards an outer target ring composed of boron eleven (11B). The accelerated protons fuse with the 11B nuclei to generate the alpha particles that then interact with crossed electric and magnetic fields between the target ring and the cavities. The alpha particles resonate with the cavities and generate a current within the resonator that is collected.

A system for radioisotope production uses fast-neutron-caused fission of depleted or naturally occurring uranium targets in an irradiation chamber. Fast fission can be enhanced by having neutrons encountering the target undergo scattering or reflection to increase each neutron's probability of causing fission (n, f) reactions in U-238. The U-238 can be deployed as one or more layers sandwiched between layers of neutron-reflecting material, or as rods surrounded by neutron-reflecting material. The gaseous fission products can be withdrawn from the irradiation chamber on a continuous basis, and the radioactive iodine isotopes (including I-131) extracted.

A pressurized water nuclear reactor (PWR) includes a once through steam generator (OTSG) disposed in a generally cylindrical pressure vessel and a divider plate spaced apart from the open end of a central riser. A sealing portion of the pressure vessel and the divider plate define an integral pressurizer volume that is separated by the divider plate from the remaining interior volume of the pressure vessel. An internal control rod drive mechanism (CRDM) has all mechanical and electromagnetomotive components including at least a motor and a lead screw disposed inside the pressure vessel. Optionally CRDM units are staggered at two or more different levels such that no two neighboring CRDM units are at the same level. Internal primary coolant pumps have all mechanical and electromagnetomotive components including at least a motor and at least one impeller disposed inside the pressure vessel. Optionally, the pumps and/or CRDM are arranged below the OTSG.

A method and apparatus for securely fastening a pipe collar or a bracket to a riser pipe of a boiling water reactor (BWR) jet pump assembly. A pipe plug assembly includes an angled pipe plug that acts as a wedge to expand a bushing assembly as the pipe plug is drawn into the overall pipe plug assembly. Expansion of the bushing assembly allows a tight tolerance to exist between an outer diameter of the pipe plug and an inner diameter of the collar/bracket and riser pipe. Expansion of the bushing assembly allows a straight hole to be match drilled into the collar/bracket and riser pipe, thereby avoiding a more complicated tapered hole to be drilled into the collar/bracket and riser pipe. An ensuing tight fit between the pipe plug assembly, the collar/bracket and the riser pipe mitigates vibration of components and minimizes leakage to acceptable levels for use in the flooded environment of the annulus region where the jet pump assembly exists in the BWR.

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 internal 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 internal pressurizer. A central riser may be disposed concentrically inside the pressure vessel, and the RCP impels primary coolant downward into a downcomer annulus between the central ser and the pressure vessel. A steam generator may be disposed in the downcomer annulus and spaced apart from with the impeller by an outlet plenum, A manway may access the outlet plenum so tube plugging can be performed on the steam generator via access through the manway without removing the RCP.

Disclosed is a zirconium alloy material having high corrosion resistance regardless of thermal history during its manufacturing process. The zirconium alloy material is obtained by providing a zirconium alloy containing on the mass basis: 0.001% to 1.9% of Sn, 0.01% to 0.3% of Fe, 0.01% to 0.3% of Cr, 0.001% to 0.3% of Ni, 0.001% to 3.0% of Nb, 0.027% or less of C, 0.025% or less of N, 4.5% or less of Hf and 0.16% or less of O with the remainder being inevitable impurities and zirconium, being formed of a bulk alloy and a surface layer, in which the surface layer has a plastic strain of 3 or more or a Vickers hardness of 260 HV or more and an arithmetic mean surface roughness Ra of 0.2 μm or less.

UO2 nuclear fuel pellets are fabricated by adding additive powder comprising Mn compound and Al compound into UO2 powder.

An axial power distribution control device includes an axial offset calculation unit 52, a parameter calculation unit 53, and an axial offset determining unit 55. The axial offset determining unit 55 predicts whether a core axial offset of the power distribution is increased or decreased after a current time, based on a major axis of an ellipse drawn by the xenon parameter and the iodine parameter calculated by the parameter calculation unit 53 and the xenon parameter and the iodine parameter at the current time. This makes it possible to predict a change of the axial offset of the power distribution of a reactor for suppressing a xenon oscillation in the reactor.

A jet pump beam (hereinafter, referred to as a beam) is fitted into a pair of projecting portions installed to a transition piece, and after the beam is arched, a beam bolt engaged with the beam is tightened. An end of the beam bolt comes in contact with a top surface of an insert member fitted into an elbow disposed between the pair of projecting portions. An ultrasonic sensor head is fixed to the beam bolt, and ultrasonic waves are sent to the beam bolt from the ultrasonic sensor in the ultrasonic sensor head. An ultrasonic measuring apparatus obtains echo intensity of each of reflected waves generated at the end of the beam bolt and a bottom surface of the insert member, and based on the echo intensities, an echo intensity ratio R is calculated. The installed state of the beam is checked using the echo intensity ratio R.

A control rod/fuel support handling apparatus that is used in the case where a control rod and a fuel support are held, removed and lifted in a reactor and then are transported into the reactor in a periodical inspection of a BWR and in the case where the control rod and the fuel support are attached and mounted again into the reactor, the control rod/fuel support handling apparatus including: a fuel support gripper that holds the fuel support with a support gripping member; a control rod gripper that includes a vertically movable and rotatable elevating/rotating unit, holds the control rod with a control rod gripping member, disconnects and connects the control rod and a control rod drive mechanism, and allows removal and attachment of the control rod; and a control panel that controls automatically controls the control rod gripper in response to the instructions from an operation pendant.

A system, method and apparatus for providing additional radiation shielding to a ventilated cask for holding high level radioactive materials. The invention utilizes a tubular shell that is ancillary to the ventilated cask that circumscribes the ventilated cask to add radiation shielding protection while improving heat removal by natural convective air flow. Because the tubular shell and cask are non-unitary and slidably separable from one another, crane lifting capacity is not affected. In one aspect, the invention is an apparatus for providing additional radiation shielding to a cask holding high level radioactive materials comprising: a tubular shell extending from an open bottom end to an open top end, the tubular shell having an inner surface that forms a cavity about a longitudinal axis; a plurality of primary apertures forming passageways through the tubular shell and circumferentially arranged in a spaced-apart manner about the tubular shell; a plurality of secondary apertures forming passageways through the tubular shell and circumferentially arranged in a spaced-apart manner about the tubular shell; and an annular seal coupled to the tubular shell and extending from the inner surface of the tubular shell; wherein the secondary apertures are located at an axial height above the annular seal and the primary apertures are located at an axial height below the annular seal.

A lid frame for a nuclear fuel assembly shipping container and a shipping container for nuclear fuel assemblies are provided. The shipping container can include a lower container in which a cradle is installed, an upper container detachably coupled to the lower container, and a base frame coupled to the cradle with at least one nuclear fuel assembly placed thereon. The lid frame can include a plurality of supports installed apart from each other so as to surround the nuclear fuel assembly placed on the base frame, and a plurality of clamps separated from each other, coupled to the plurality of supports perpendicular to the plurality of supports, rotatably hinged to the base frame, and configured to clamp the nuclear fuel assembly. The lid frame safely protects the nuclear fuel assembly that is being transported.

A neutron generator includes an ion source disposed in a pressurized environment containing an ionizable gas. The ion source includes a substrate with a bundle of carbon nanotubes extending therefrom. The ends of the nanotubes are spaced from a grid. Ion source voltage supply circuitry supplies a positive voltage potential between the substrate and the grid of the ion source to cause ionization of the ionizable gas and emission of ions through the grid. An ion accelerator section is disposed between the ion source and a target. The ion accelerator section accelerates ions that pass through the grid towards the target such that collisions of the ions with the target cause the target to generate and emit neutrons therefrom. The ion source, accelerator section and target are housed in a sealed tube and preferably the carbon nanotubes of the bundle are highly ordered with at least 106 carbon nanotubes per cm2 that extend in a direction substantially parallel to the central axis of the tube. The neutron generator provides gas ionization at much higher atomic to molecular ratio that the prior art, which allows for small compact size designs suitable for logging tools that are used in space-constrained downhole environments.

Electrochemical corrosion potential (ECP) probe assemblies may be used to monitor ECP of materials due to coolant chemistry in an operating nuclear reactor. Example embodiment assemblies include at least one ECP probe that detects ECP of potentially several different materials, a structural body providing a fluid flow path for the coolant over the ECP probes, and a signal transmitter that transmits or carries ECP data to an external receiver. The ECP probes may be of any number and/or type, so as to detect ECP for different component materials, including stainless steel, a zirconium alloys, etc. The ECP probes may further detect ECP due to ion concentration, pH, etc. The ECP data may be transmitted through wired or wireless signal transmitters. Example methods include installing and using example embodiment ECP probe assemblies in nuclear reactors and facilities.

The present invention provides a system and method for reclaiming energy from the heat emanating from spent nuclear fuel contained within a canister-based dry storage system. The inventive system and method provides continuous passive cooling of the loaded canisters by utilizing the chimney-effect and reclaims the energy from the air that is heated by the canisters. The inventive system and method, in one embodiment, is particularly suited to store the canisters below-grade, thereby utilizing the natural radiation shielding properties of the sub-grade while still facilitating passive air cooling of the canisters. In another embodiment, the invention focuses on a special arrangement of the spent nuclear fuel within the canisters so that spent nuclear fuel that is hotter than that which is typically allowed to be withdrawn from the spent fuel pools can be used in a dry-storage environment, thereby increasing the amount energy that can be reclaimed.

Disclosed is a system for producing electromagnetic radiation with enhancement from a drift tube containing a cylindrical Smith-Purcell structure. The system includes a magnetically insulated linear oscillator. The oscillator includes a cylindrical resonant cavity having a traveling wave electron gun and a cooperating anode. The drift tube is formed of a hollow cylindrical conductive element that is positioned within a resonant cavity of the oscillator. The drift tube includes an inner surface and a pair of ends. The drift tube may be adapted such that the interaction between an electron beam, from the electron gun, passes through the inner space of the drift tube, and the internal grating, so as to produce RF radiation by the Smith-Purcell Effect. Spacing, face angle and shape of the grating, and the energy of the electron beam are determinants of the frequency of the RF radiation.

Aspects of the invention relate to several methods to deposit and regenerate target materials in neutron generators and similar nuclear reaction devices. In situ deposition and regeneration of a target material reduces tube degradation of the nuclear reaction device and covers impurities on the surface of the target material at the target location. Further aspects of the invention include a method of designing a target to generate neutrons at a high efficiency rate and at a selected neutron energy from a neutron energy spectrum.

Disclosed embodiments include electromagnetic flow regulators for regulating flow of an electrically conductive fluid, systems for regulating flow of an electrically conductive fluid, methods of regulating flow of an electrically conductive fluid, nuclear fission reactors, systems for regulating flow of an electrically conductive reactor coolant, and methods of regulating flow of an electrically conductive reactor coolant in a nuclear fission reactor.

Illustrative embodiments provide systems, methods, apparatuses, and applications related to annealing nuclear fission reactor materials.

Apparatus and methods for determining the absence or presence of contraband in an object with a fast neutron source for irradiating the object; a detector for measuring γ-rays emitted by the irradiated object from energy state relaxation as a result of neutron capture, typically after the object has been irradiated.

Disclosed is a coolant with dispersed neutron poison micro-particles, used in a supercritical water-cooled reactor (SCWR) emergency core cooling system. Since the neutron poison micro-particles are uniformly dispersed in the coolant of the emergency core cooling system for a long period time, their fluidity is not lowered even though the polarity of water is changed in a supercritical state. Therefore, the neutron poison micro-particles absorb neutrons produced from nuclear fission in a nuclear reactor core. Accordingly, the neutron poison micro-particles can be appropriately used as a means for controlling neutrons and stopping a nuclear reactor in the SCWR emergency core cooling system.

A nuclear fuel assembly tie plate is provided. The nuclear fuel assembly tie plate is formed by intersecting strips delimiting between them tubular guide cells each for allowing a fuel rod to extend through the tie plate. The strips delimit between them tubular flow cells separate from the guide cells, each flow cell for allowing coolant flow through the tie plate. Guide cells and flow cells are arranged at nodes of a lattice defined by a repeating pattern comprising four corner nodes in a square lattice arrangement and a central node at the center of the four corner nodes, with one guide cell at each corner nodes, separated by a pair of parallel spaced strips intersecting a pair of parallel spaced strips, the two pairs of strips delimiting a four-walled central flow cell at the center node.

This document's object is to provide an axial power distribution control method in which only the control of an axial power distribution in a nuclear reactor with a simple operation with a clear operational target keeps the control of a xenon oscillation, thereby suppressing the xenon oscillation to an extremely small magnitude in advance at the same time. An axial power distribution control method comprises an axial offset calculation step of calculating an axial offset of the current power distribution (AOP) and axial offsets of the power distributions (AOX, AOI) which would give the current xenon and iodine distributions under equilibrium conditions, respectively, based on relative powers (PT, PB) in the upper and lower halves of the nuclear reactor core, a parameter calculation step of calculating parameters (DAOPX, DAOIX), a trajectory display step of displaying a trajectory to plot the parameters (DAOPX, DAOIX) on one and the other axis, respectively, an allowable range excess judgment step of judging if the axial offset of the current power distribution (AOP) exceeds an allowable range, an alarming step of giving the alarm when the AOP exceeds the allowable range, and a control rod moving step of controlling the movement of control rods to guide the plot to the major axis of an ellipse formed by the trajectory of said parameters upon receipt of the alarm.

An improved grid for a nuclear reactor fuel assembly that has an egg-crate base grid as the primary support structure with each support cell of the base grid that supports a fuel rod having a lock-support sleeve that is rotatable within the support cell between a first and second orientation. In the first orientation the lock-support sleeve fits loosely within the support cell of the base grid and respectively, loosely receives the fuel rods that are loaded therein. The lock-support sleeves are then rotated to a second orientation that locks the fuel rods axially within the support cells.

A plug for heat-conducting tubes is equipped with: a plug main body, which is formed so as to be capable of being inserted into the heat-conducting tubes; a columnar member, which is capable of being inserted into and removed from the plug main body from the cylindrical open end of the plug main body, and has at its outer circumference a tapered surface; and a wedge member, which is formed so as to be capable of being inserted into and removed from the plug main body from the cylindrical open end of the plug main body, and has at its inner circumference a tapered surface which opposes the tapered surface of the columnar member when the wedge member is inserted into the plug main body.

A cask cushioning body includes an end-surface side member (2) in which a plurality of plates (21, 22) made of steel are formed at a distance between plate surfaces of the plates (21, 22) that face each other, and in which the plate surfaces of the plates (21, 22) are arranged along an end surface (100a) of a cask (100), and a circumferential-surface side member (3) that forms a cylindrical body (31) made of steel, one end of which is connected to a periphery of the end-surface side member (2), and that is arranged along an end-portion outer-circumferential surface (100b), wherein an impact absorber (4) that absorbs an impact by deforming is provided outside of the end-surface side member (2) and the circumferential-surface side member (3).

Nonconjugated conductive polymers absorb radioactive iodine, therefore are useful for protection against nuclear radiation. These polymers have at least one double bond per repeat unit. The ratio of the number of double bonds to the total number of bonds along the polymer chain is less than half. Examples of nonconjugated conductive polymers include: cis-1,4-polyisoprene (natural rubber), trans-1,4-polyisoprene (gutta percha), polybutadiene, polydimethyl butadiene, poly(b-pinene), styrene butadiene rubber (SBR), polyalloocimene, polynorbornene and many others. Through interaction with iodine atoms the double bonds in the nonconjugated polymers transform into radical cations leading to a dark color. The iodine atoms remain (immobile) bound to the polymer chain through the charge-transfer interaction, these polymers are very inexpensive and can be easily processed into any shape, structure and size. Therefore, these are useful for protection against nuclear radiation including radioactive iodine. These polymers when used as a thick cover can provide safe storage of nuclear waste materials including spent fuel rods.

A compressor assembly and the method of using the same which includes an elongated spiral passageway within which a compact toroid plasma, such as a compact toroid plasma structure, can be efficiently compressed to a high-energy state by compressing the compact toroid plasma structure by its own momentum against the wall of the spiral passageway in a manner to induce heating by conservation of energy. The compressor assembly also includes a burn chamber that is in communication with the spiral passageway and into which the compressed compact toroid plasma structure is introduced following its compression.

A method for obtaining free thermal antineutrons within the cage-like structure of a fullerene molecule comprising irradiating the fullerene molecule with free neutrons causing free neutrons to be trapped within the fullerene molecule wherein the trapped neutron oscillates between the neutron and antineutron states. A method for producing antiprotons comprising irradiating a fullerene molecule with free neutrons and trapping the neutrons within the fullerene molecule such that the neutrons oscillate between neutron and antineutron states and in the antineutron state decay and produce antiprotons. A method for producing antiprotonic x-ray cascade spectra.

A method and apparatus for the calibration of neutron flux monitoring devices used in a nuclear reactor core. The apparatus includes a transverse in-core probe (TIP) cable with a neutron absorber located a fixed distance apart from a TIP detector. The neutron absorber may be passed within close proximity of the neutron flux monitoring device such that a perceived drop in measured neutron flux occurs, whereupon the cable may be repositioned relative to the monitoring device to ensure that the TIP detector is within close proximity of the monitoring device for purposes of calibrating the monitoring device.

A CRDS unlatching tool includes a support assembly and a latching assembly, wherein the support assembly is received within the latching assembly in a manner wherein the latching assembly is moveable relative to the support assembly. The support assembly has a plurality of latch fingers and at least one pin, each of the latch fingers being movable between a latched position wherein the latch finger is structured to engage and hold the CRDS an unlatched position wherein the latch finger is structured to not engage the CRDS. The latching assembly includes a first sleeve member and a second sleeve member, the second sleeve member having at least one slot, wherein the at least one pin is moveably received within the at least one slot. The latching assembly is movable from a latched state to an unlatched state wherein the latch fingers are actuated by the first sleeve member.

There is provided a holding device which can hold a molten corium for a predetermined period even when the molten corium is exposed to heat or undergoes any chemical reaction and which is applicable to practical use. There is provided a holding device provided below a nuclear reactor pressure vessel for holding a molten corium, wherein the holding device includes a base material in contact with a cooling medium, and a multilayer stack structure on the base material. The multilayer stack structure has a first layer having heat-resistant property, a second layer formed on the first layer and having heat-resistant property with lower heat conductivity than that of the first layer, and a third layer formed on the second layer and having corrosion-resistant property and impact-absorbing property.

A method of fabricating a nuclear fuel comprising a fissile material, one or more hollow microballoons, a phenolic resin, and metal matrix. The fissile material, phenolic resin and the one or more hollow microballoons are combined. The combined fissile material, phenolic resin and the hollow microballoons are heated sufficiently to form at least some fissile material carbides creating a nuclear fuel particle. The resulting nuclear fuel particle comprises one or more fission product collection spaces. In a preferred embodiment, the fissile material, phenolic resin and the one or more hollow microballoons are combined by forming the fissile material into microspheres. The fissile material microspheres are then overcoated with the phenolic resin and microballoon. In another preferred embodiment, the fissile material, phenolic resin and the one or more hollow microballoons are combined by overcoating the microballoon with the fissile material, and phenolic resin.

An emergency core cooling system is provided with a hybrid safety system composed of an active safety system and a static safety system for ensuring the safety against a severe natural phenomenon such as a giant earthquake and a mega hurricane. An emergency core cooling system for a boiling water reactor includes four safety divisions in total: three safety divisions for an active safety system having a high pressure reactor core cooling system, a low pressure reactor core cooling system, a residual heat removal system, and an emergency diesel generator; and one safety division for a static safety system having an isolation condenser, a gravity drop reactor core cooling system, and a static containment vessel cooling system.

The invention relates to a nuclear fuel cladding totally or partially made of a composite material with a ceramic matrix containing silicon carbide (SiC) fibers as a matrix reinforcement and an interphase layer provided between the matrix and the fibers, the matrix including silicon carbide as well as at least one of the following additional carbides: titanium carbide (TiC), zirconium carbide (Zrc), and ternary titanium silicon carbide (Ti3SiC2). When irradiated and at temperatures of between 800° C. and 1200° C., said cladding can mechanically maintain the nuclear fuel within the cladding while enabling optimal thermal-energy transfer towards the coolant. The invention also relates to a method for making the nuclear fuel cladding.

The invention refers to a fuel assembly comprising a lower end structure, an upper end structure including a top nozzle (5), a plurality of fuel rods and a plurality of guide thimbles (3). The top nozzle includes a passageway and an annular groove (10) in said passageway. A sleeve (11) is provided for attaching the guide thimble (3) to the top nozzle (5). The sleeve has at least three slots (12) and includes at least three bulges (13). Each bulge (13) has two ends and extends between two of the slots (12). At least one of the ends of the bulge (13) extends to a position at a distance (d) from the respective slot (12). The invention also refers to a guide thimble device (9) for use in a fuel assembly.

Disclosed is a system for extracting energy from inertial confinement fusion reactions, which includes a central target chamber for receiving fusion target material. A plurality of energy drivers are arranged around the target chamber so as to supply energy to fusion target material in the chamber to initiate an inertial confinement fusion reaction of the material, releasing energy in the forms of fusion plasma and heat. A plurality of structures for extracting energy from the fusion reaction are provided, and comprise devices to extract high voltage DC energy from the fusion plasma, and means to extract thermal energy from the central target chamber. Power to the energy drivers may be supplied from high voltage DC energy extracted from the fusion reactions. The energy drivers may use an apodizing filter to impart a desired shape to the wavefront of the driving energy for causing the fusion reactions, to avoid hydrodynamic instabilities.