Abstract: A method for controlling a pressurized water nuclear reactor is provided, including core producing thermal power, sensors for acquiring the mean temperature of the primary coolant and for calculating the thermal power, actuators for controlling the axial distribution of power, the control method including: a first control phase for controlling the reactor during normal operation by controlling the mean temperature of the primary coolant so as to make it correspond to a reference temperature profile (Pref) dependent on the thermal power of the reactor; and a second control phase, referred to as stretchout, that occurs after normal operation of the reactor in order to control the reactor in stretchout by controlling the axial distribution of power, the mean temperature varying freely in a temperature range delimited by an upper limit and a lower limit.

Abstract: A method for inspecting a surface (12) of a piece of nuclear power plant equipment includes scanning the surface (12) with an acquisition field (20) of a matrix array camera (14). The acquisition field (20) moves relative to the surface (12) at a movement speed. The method also includes acquiring, by means of the matrix array camera (14), an image (22) of the acquisition field (20), with a certain acquisition frequency. Each image (22) includes a first number of lines of pixels. The method also includes extracting, from each image (22), a first set of lines, the first set comprising a second number of continuous lines of pixels, the second number being between 2 and the first number; and constituting a final image (32) of the surface (12) by juxtaposing the lines extracted from each image (22). The movement speed, the acquisition frequency, the first number of lines and the second number of lines are chosen such that the final image (32) covers the entire surface (12) without interruption.

Abstract: An assembly for acting on the outer surface of a tube, and corresponding method are provided. The assembly includes a carrier; at least one inspection or maintenance tool; the carrier includes at least one rolling body; an actuator. The carrier further includes a device for connecting the carrier to the tube, arranged so that the tube absorbs at least 50% of the weight of the carrier and the tool.

Abstract: A packing seal is provided for a system for sealing the shaft of a primary motor-driven pump unit of a nuclear reactor, intended to ensure sealing between the primary circuit and the atmosphere. The packing seal including a rotary active surface and a floating active surface, in which a face of the floating active surface and/or the rotary active surface is micro- or nano-structured by an array of holes or pillars, each hole or pillar having lateral dimensions and a height of between 10 nm and 5 ?m, the distance between two consecutive holes or pillars being between 10 nm and 5 ?m.

Abstract: A vibration-inhibiting bar is provided that is interposed between bends of the tubes of two adjacent banks of tubes of a U tube bundle of a steam generator and includes at least one internal element, referred to as a damping element, designed to mechanically damp the vibrations of the tubes; and at least one external element, referred to as percussion element, in contact with the damping element, the percussion element being designed to be in contact with the bends of the tubes of the bundle.

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 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 field programmable gate array comprising: plurality of functional blocks at least one of the functional blocks comprising at least one function, at least one of the functions using a parameter, wherein the functional blocks are adapted to perform the at least one function in a calculation phase; a data conveyor comprising a plurality of data slots, wherein each functional block is, in a data transfer phase, adapted to receive input data from one or more predefined first slots and/or to provide output data into one or more predefined second slots; and a configuration circuit adapted to configure the parameter for the at least function using the parameter and to define the one or more first slots and/or the one or more second slots for at least one functional block, wherein the field programmable gate array is adapted to cyclically repeat the data transfer phase and calculation phase.

Abstract: An assembly is provided that includes a device for locking tubes in position relative to one another, with at least a first arm, a locking axle having a plurality of bearing surfaces, the locking axle being movable between a position locking the tubes each between one of said bearing surfaces and the first arm, and a released position, in which the tube segments are free.

Abstract: An insertion assembly (1) includes a frame (11), having a longitudinal passage (13) for the thermocouple (3); a device (15) for blocking the pipe (5) in position relative to the frame (11); a device (17) for guiding the thermocouple along the passage (13); and a device (19) for driving the thermocouple (3). The driving device (19) includes at least a first drive belt (21) having a first longitudinal segment (25) pressed against the thermocouple (3), and a motor member driving said first segment (25) of the first belt (21) longitudinally relative to the frame (11).

Abstract: The present invention relates to a passive shutdown sealing device (20) for a reactor coolant pump unit comprising: a split sealing ring (23) having an inactivated position in which a leakage flow is permitted and an activated position in which said ring stops said leakage flow; at least one piston (22) designed to position said split sealing ring (23) in its activated position; locking/unlocking means (25) designed to lock said at least one piston (22) in its inactivated position when the temperature of said locking/unlocking means is below a temperature threshold and to release said at least one piston (22) when the temperature of said locking/unlocking means is above said temperature threshold; elastic means (24) designed to move said at least one piston (22) when said piston is released, so as to position said sealing ring (23) in its activated position.

Abstract: A method for simulating the fluid flow in a vessel of a nuclear reactor is provided. The reactor includes a core inside the vessel, the core including a lower plate, an upper plate and fuel assemblies extending between the plates, and having a volume axially delimited by first and second interfaces corresponding to the plates. The method includes computing, for the core volume, the fluid pressure and speed, from an initial value of the speed or pressure in the first interface and respectively in the second interface, and using the fluid mass, movement quantity and energy balance equations.

Abstract: A method for simulating the flow of a fluid in a vessel of a nuclear reactor is provided. The nuclear reactor includes the vessel and a core inside the vessel, the core including nuclear fuel assemblies, each one extending in an axial direction, including nuclear fuel rods and a grid for maintaining the rods, and being spaced apart from another by a clearance between the grids in a transverse direction. This method for simulating a fluid flow in the vessel of a nuclear reactor includes determining of head loss coefficients in the core, and computing the fluid pressure and speed component(s) in the core using the equation: ?P=?K×V where P is the component of the fluid pressure, K is a matrix including the determined head loss coefficients, and V is a vector including the fluid speed component(s).

Abstract: An ultrasound transducer is provided. The ultrasound transducer include at least one emitter made from a piezoelectric material, having first and second emitting surfaces opposite one another provided to emit first and second ultrasound beams. The transducer comprises at least first and second mirrors placed across from the first and second emitting surfaces, respectively, and configured so as to deflect back the first and second ultrasound beams by forming a reflected beam with a predetermined shape.

Abstract: A method is provided for operating a nuclear reactor. The method includes operating the nuclear reactor for at least one plutonium equilibrium cycle during which the core contains plutonium-equilibrium nuclear fuel assemblies; subsequently, operating the reactor for transition cycles, at least some of the plutonium-equilibrium nuclear fuel assemblies being progressively replaced with transition nuclear fuel assemblies and then with uranium-equilibrium nuclear fuel assemblies; and then operating the nuclear reactor for at least one uranium equilibrium cycle.

Abstract: A packing seal is provided for a system for sealing the shaft of a primary motor-driven pump unit of a nuclear reactor, intended to ensure sealing between the primary circuit and the atmosphere. The packing seal includes a rotary active surface and a floating active surface, and a face of the floating active surface and/or the rotary active surface is covered by a protective layer made from a material having surface energy greater than 30 mJ/m2 and an electron donor component less than 15 mJ/m2.

Abstract: A treatment process for a zirconium alloy is provided. The process includes the following steps: a zirconium alloy ingot is prepared, the composition of which is: 0.40%?Nb?1.05%; traces?Sn?2%; (0.5Nb?0.25) %?Fe?0.50%; traces?Ni?0.10%; traces?(Cr+V) %?0.50%; traces?S?35 ppm; 600 ppm?O?2000 ppm, preferably 1200 ppm?O?1600 ppm; traces?Si?120 ppm; traces?C?150 ppm; the remaining being Zr and unavoidable impurities; the ingot undergoes at least one reheating and hot shaping step, and possibly a reheating and quenching step following a hot shaping step; optionally the hot-shaped ingot undergoes an annealing; the hot-shaped and possibly annealed ingot undergoes at least one cycle of cold rolling-annealing steps; the annealing of at least one of the cold rolling-annealing steps being performed at a temperature comprised between 600° C. and the lowest of either 700° C. or (710?20×Nb %)° C.

Abstract: A device and method for three-dimensional reconstruction of a scene by image analysis is provided. This device comprises an image acquisition device to capture images of the scene, an analysis device to calculate a three-dimensional reconstruction of the scene from at least one image of the scene taken by the image acquisition device, and a projection device to project a first light pattern and a second light pattern, which are complementary, on the examined scene, the first light pattern and the second light pattern being projected along separate projection axes forming a non-zero angle between them, so as to be superimposed while forming a uniform image with homogenous intensity in a projection plane.

Abstract: A cladding tube for nuclear fuel made from metal and including concave dimples on its external surface. A nuclear fuel assembly includes at least a plurality of nuclear fuel rods provided with such cladding tubes. The cladding tube is advantageously manufactured by pilgrim rolling, the dimples being formed during the pilgrim rolling.

Abstract: A connecting device including a nut, a screw, a body having a bore for screwing the screw to the nut through the bore with the screw abutting an abutment surface of the body, a screw locking device for preventing loosening of the screw. According to one aspect of the invention, the locking device is adapted for axially retaining the screw into the body after unscrewing the screw.