Abstract: A BWR fuel assembly is elongated along a fuel assembly axis and comprises a lower tie plate, an upper tie plate axially spaced from the lower tie plate, a bundle of fuel rods extending axially between the lower tie plate and the upper tie plate, and a tubular fuel channel extending from the lower tie plate to the upper tie plate with encasing the fuel rods. The fuel assembly comprises an interaction device mounted on the lower tie plate and configured to interact with the fuel channel. The interaction device has an inactive configuration and an active configuration.

Abstract: A nuclear fuel assembly bottom end part debris filter has an inlet face (18A) and an outlet face (18B) opposed to the inlet face (18A) and comprises a plurality of filtering structures (50) protruding on the inlet face (18A) of the debris filter (18). Each filtering structure (50) has a structure base (52) and a structure apex (54) spaced along a structure axis (A), and each filtering structure (50) includes blades (56) distributed circumferentially around the structure axis (A). Each blade has one end connected to the structure base (52) and one end connected to the structure apex (54), and each blade (56) delimits a slot (58) with each adjacent blade (56) of the same filtering structure (50).

Abstract: A debris filter configured for a nuclear fuel assembly bottom end part includes a lower nozzle (8) and the debris filter (18) is supported by the lower nozzle (8). The debris filter (18) has an inlet face (18A) and an outlet face (18B) opposed to the inlet face (18A), and comprises at least one filtering section (18D) that has a retention capacity that increases gradually or stepwise towards from the inlet face (18A) to the outlet face (18B).

Abstract: A nuclear fuel assembly for a boiling water reactor extends along a fuel assembly axis and includes a base including a lower tie plate, a head including an upper tie plate and a lift handle, a bundle of fuel rods extending axially between the lower tie plate and the upper tie plate, and a water channel extending within the bundle of fuel rods with axially connecting the base to the head such that the load of the base is transferred to the head via the water channel. The fuel assembly further comprises a tie rod extending between the base and the head. The tie rod is axially fixed to the base and connected to the head via a connection assembly comprising a stopping member configured to abut an abutting surface of the head for limiting a downward movement of the base relative to the head during lifting of the fuel assembly, in case of a breakage of the water channel.

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: 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 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: A debris filter for a nuclear reactor installation is provided. The debris filter comprises a plurality of plates arranged side-by-side in a spaced relationship and delimiting between them flow passages extending through the debris filter from a lower inlet face to an upper outlet face of the debris filter, each passage having an intermediate section offset with respect to an inlet section and an outlet section. At least one of the plates is formed with debris catching features distributed along the plate and protruding into at least one passage delimited by the plate.

Abstract: 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.

Abstract: 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.

Abstract: A nuclear fuel assembly for boiling water reactor is provided. The nuclear fuel assembly includes a base, a head, a bundle of fuel rods extending longitudinally between the base and the head, a tubular fuel channel encasing the bundle of fuel rods, and at least one fuel channel spacer for transversely spacing the fuel assembly from an adjacent element. The or each fuel channel spacer includes a support having at least one plate and at least one corresponding leaf spring supported by the corresponding plate, the or each plate being fixed to a corresponding sidewall of the fuel channel.

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 channelling 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 debris filter for a nuclear reactor installation is provided. The debris filter comprises a plurality of plates arranged side-by-side in a spaced relationship and delimiting between them flow passages extending through the debris filter from a lower inlet face to an upper outlet face of the debris filter, each passage having an intermediate section offset with respect to an inlet section and an outlet section. At least one of the plates is formed with debris catching features distributed along the plate and protruding into at least one passage delimited by the plate.

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: 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: A grid-shaped spacer includes a sheet-metal web having a web aperture formed therein defining two spaced mutually opposite aperture edges. The aperture edges oppose an elongation of an elongate spring which is curved about a direction transverse to its own longitudinal direction and which has a tab that engages through the web aperture at each of two spring ends. At least one of the tabs is snapped into a notch formed in one of the spring edges opposing the elongation of the spring.