Abstract: A method for controlling the positions of a plurality of nuclear fuel assemblies (1) relative to an upper core plate (3) in a nuclear reactor core, the method including the following steps: choosing a reference point (13) in internals or in a reactor vessel; determining the positions of S-shaped holes of the nuclear fuel assemblies (1) relative to the reference point (13), each S-shaped hole being intended to cooperate with a corresponding centering pin of the upper core plate (3); acquiring the positions of the centering pins of the upper core plate (3) relative to the reference point (13); and comparing the positions of the S-shaped holes and the positions of the pins and deducing therefrom whether the nuclear fuel assemblies (1) are correctly positioned relative to the upper core plate (3).

Abstract: A method involving periodic implementation, during the same operating cycle of the reactor, the method including following steps of: a) calculating, from measurements provided by sensors present in the reactor, the three-dimensional distribution of the local power in the core, b) simulating at least one accidental transient occurrence of power applied to the calculated three-dimensional distribution of local power, c) identifying, using thermomechanical calculations, at least one rod which is the most likely to be subject to a fracture of the cladding thereof during the simulated transient occurrence of power, and d) determining, using thermomechanical calculations on the rod identified, the value of the parameter which is representative of the operability of the reactor.

Abstract: The present invention concerns a mosaic module for a control panel of a power plant, the control panel comprising a plurality of mosaic modules being arranged adjacent to each other, each mosaic module being adapted to be fixed to a mechanical support structure, the mosaic module comprising: at least one display device for displaying a function of the power plant and/or an input device, at least one optical power supply input for receiving a power supply for the mosaic module via one or more first optical links, and at least one optical data input for receiving data to be displayed on the display device and/or at least one optical data output to transmit an input command received from the input device.

Abstract: The strip is of the type comprising a wall portion for delimiting a cell with interlaced strips, a spring formed in the strip and provided on the wall portion for biasing a fuel rod extending through the cell away from the wall portion, the spring comprising a cantilevered tab formed in the strip and a contact portion formed at least partially in the tab and protruding from the tab for contacting a fuel rod received in the cell.

Abstract: This invention relates to a control method for a pressurized water nuclear reactor, which comprises a core generating thermal power and means of acquiring magnitudes representative of core operating conditions. The method comprises a step to regulate the temperature of the primary coolant, if the temperature of the primary coolant for a given thermal power is outside a predefined set temperature interval (?TREF) depending on the reactor power. The set temperature interval (?TREF) is characterized by variable amplitude (?T) on a thermal power range between N % and 100% nominal power, where N is between 0 and 100 and comprises a zero amplitude at 100% nominal power, a zero amplitude at N % nominal power.

Abstract: A fuel rod support insert for a nuclear fuel assembly spacer grid, a spacer grid and a nuclear fuel assembly are provided. The support insert is for a nuclear fuel assembly spacer grid comprising interlaced straps defining a lattice of cells for receiving fuel rods, the insert being adapted to be secured to the straps for extending in at least one cell. The insert extends along an axis intended to be parallel to that of a cell and comprises two axially spaced end portions for connecting the insert to the straps and at least one elongated blade-like spring extending axially between the end portions for supporting a fuel rod. The spring has a non-rectilinear cross-section in each plane perpendicular to the insert axis.

Abstract: A method for producing a wear-resistant and corrosion-resistant stainless steel part for a nuclear reactor is provided. This method includes steps of providing a tubular blank in austenitic stainless steel whose carbon content is equal to or lower than 0.03% by weight; shaping the blank; finishing the blank to form the cladding; hardening the outer surface of the cladding by diffusing one or more atomic species; the blank, before the providing step or during the shaping or finishing step, being subjected to at least one hyper quenching with sub-steps of: heating the blank to a sufficient temperature and for a sufficient time to solubilize any precipitates present; quenching the blank at a rate allowing the austenitic structure to be maintained in a metastable state at ambient temperature and free of precipitates.

Abstract: A method for carrying out emergent shaft sealing for a reactor coolant pump and a shaft sealing assembly is provided. The method comprises the steps that a passive stopping sealing member is arranged in a first sealing assembly and forms an opening under the normal operation condition, without affecting the first sealing assembly using a liquid film formed by fluid static pressure to prevent reactor coolant from leaking along a pump shaft; under the station blackout condition, after sensing high-temperature fluid flowing into the first sealing assembly, the passive stopping sealing member is closed and holds the pump shaft of the reactor coolant pump tightly, the gap between the first sealing assembly and the pump shaft of the reactor coolant pump is blocked, and therefore the reactor coolant is prevented from leaking along the pump shaft.

Abstract: A photothermal examination method and corresponding examination unit are provided. In the method first and second zones of the surface to be characterized are scanned simultaneously, and first and second photosensitive surfaces separate from one another acquire images of the infrared radiation emitted by these two zones.

Abstract: The present invention relates to a method for controlling a pressurized water reactor (100) comprising the steps that involve measuring the effective power (Pe) of the nuclear reactor; acquiring a reference value for the desired power (Pc); acquiring an estimated duration (DURATION) for the increase in power in order to achieve said reference value of the target power (Pc) desired, said estimated duration (DURATION) corresponding to the time taken for the power to increase from said effective power (Pe) to said reference value for the target power (Pc); determining the reference position (Z) of at least one control rod cluster among said plurality of control rod clusters (40) in order to achieve said reference value for said target power (Pc) desired as a function of said estimated duration (DURATION), of said measured effective power (Pe) and of said reference value for said target power (Pc); monitoring the position of said at least one control rod cluster so as to position it in its reference position (Z).

Abstract: A method for thermochemically treating a part while masking a portion and corresponding mask are provided. The method includes the steps of providing a mask comprising a body with a seat, at least a deformable sealing washer located in the seat, and a tightening bushing, the body having a cavity, placing a first portion of the part in the cavity, a second portion of the part being located in a passage in the sealing washer, and a third portion of the part being located outside the mask, moving the tightening bushing to its tightened position so that the sealing washer is deformed and applied against the second portion of the part, and applying a thermochemical treatment to the third portion of the part.

Abstract: A nuclear facility comprising an anchor device is provided. This anchor device comprises a female part and a male part. The female part includes a groove extending along a longitudinal axis. The groove has a width which decreases longitudinally and a transverse section. The male part includes a slider with a shape mating that of the groove and is able to be longitudinally inserted into the groove. The transverse section of the groove is configured so as to prevent the extraction of the slider out of the groove transversely to the longitudinal axis. The anchor device includes a locking device able to prevent the slider from longitudinally sliding out of the groove.

Abstract: A nuclear fuel assembly spacer grid defining a lattice of cells for receiving fuel rods is provided. The spacer grid includes a peripheral band composed of at least one peripheral strip delimiting a portion of the peripheral contour of the spacer grid, and at least one spacer grid positioning spring elastically deformable and formed in the peripheral band.

Abstract: An enhancing device for piercing plugs in a steam generator is provided. The enhancing device includes a main body, and a bit, borne by the main body and extending along a longitudinal axis. The bit may be driven into rotation around its longitudinal axis, in order to perform an action for piercing a plug. The device includes a hollow tubular element, extending along the longitudinal axis, while surrounding the bit and coaxially with this bit, the tubular element including an outer surface having a screwing thread, intended to be screwed onto the plug prior to the piercing. The tubular element may be driven into rotation around the longitudinal axis, independently of the rotation of the bit.

Abstract: A lower nozzle for use in a nuclear fuel assembly provided. The lower nozzle is of the type having an axis and comprising a transverse lower tie plate for channeling the coolant through the lower tie plate and a tubular skirt extending axially from the periphery of the lower tie plate, the skirt delimiting an axial housing closed at one end by the lower tie plate and open at the opposite end, a debris filter configured for axial insertion in the housing and snap-fit springs for retaining the debris filter in the housing after insertion. The springs are configured to shift the debris filter axially towards the lower tie plate.

Abstract: A circuit arrangement, in particular for a safety I&C system of a nuclear power plant, keeps a proven diagram-centric project-specific engineering approach known from CPU-based systems while reaping the benefits of FPGA technology. To this end, the circuit arrangement includes: a generic FPGA with a plurality of logic blocks, and at least one dedicated PLD which operates as an application-specific switch-matrix for the logic blocks.

Abstract: A lifting beam is provided. The lifting beam includes a lower beam and an upper beam arranged above the lower beam; an arranger for arranging the beams in close and releasable engagement with one another; and systems for gripping the load. The gripping systems are kept in an open position when the beams are in engagement with one another, and in a closed position when an engager is released.

Abstract: The invention relates to a heating rod for a pressurizer of a primary cooling system of a pressurized-water nuclear reactor, the rod comprising a metal outer shell (36) of longitudinally elongate shape having an external surface (62), and a heating element (40) mounted inside the shell (36). It comprises an anti-corrosion coating (60) covering at least part of the external surface (62) of the shell (36).

Abstract: A nuclear fuel assembly is provided for a boiling water reactor. The nuclear fuel assembly includes a base, a head, and a bundle of full length fuel rods and partial length fuel rods, said bundle extending upwardly and longitudinally from the base to the head. The nuclear fuel assembly includes at least one clamp for longitudinally retaining a lower plug of a partial length fuel rod with respect to the base. The clamp is an additional part fitted to the base, the clamp is at least partially received in a housing provided in the base, and the clamp is assembled to the base by mechanical engagement of complementary assemblies.

Abstract: An assembly is provided that includes at least one first conduit and at least one second conduit connected together through a connecting device. The connecting device includes an exteriorly threaded tube; a connecting part attached to one end of the tube and including an orifice; a holding nut screwed onto the tube and axially maintaining the connecting part relative to a tube; and a retaining member attached on the holding nut and engaging with the first conduit so as to axially retain the first conduit fitted into the orifice, the retaining member cooperating with the first conduit so as to oppose the unscrewing of the holding nut.