Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
  • G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
  • G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
  • G21C3/3206—Means associated with the fuel bundle for filtering the coolant, e.g. nozzles, grids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
  • B01D29/01—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements
  • B01D29/03—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements self-supporting
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
  • G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
  • G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
  • G21C3/33—Supporting or hanging of elements in the bundle; Means forming part of the bundle for inserting it into, or removing it from, the core; Means for coupling adjacent bundles
  • G21C3/3305—Lower nozzle
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E30/00—Energy generation of nuclear origin
  • Y02E30/30—Nuclear fission reactors

Definitions

• the present invention relates to the field of nuclear fuel assemblies, in particular for pressurized water nuclear reactors (or PWR for “Pressurized Water Reactor”).
• a nuclear fuel assembly for a pressurized water nuclear reactor generally includes a bundle of nuclear fuel rods extending along a longitudinal axis and a support skeleton configured to support the nuclear fuel rods.
• the support skeleton comprises a lower end and an upper end spaced apart along the longitudinal axis, a plurality of guide tubes extending along the longitudinal axis by connecting the ends to one another, and distributed spacer grids along the guide tubes and fixed to the guide tubes, each spacer grid being configured to support the nuclear fuel rods.
• the nuclear fuel assembly is arranged vertically in a vessel of a nuclear reactor, being placed on a lower core plate provided with openings through which a cooling fluid enters which circulates vertically from bottom to top through nuclear fuel assembly.
• the invention proposes an anti-debris filter for the lower end of a nuclear fuel assembly, the anti-debris filter being formed of a grid having a first face and a second opposite face, the grid having passages s 'extending between an inlet located on the first face and an outlet located on the second face for the flow of a cooling fluid through the grid, the grid having a first zone and at least a second zone in which the grid has a thickness greater than that of the grid in the first zone, passages being present in the first zone and in each second zone.
• the zones of different thicknesses allow the debris retention capacity and flow resistance of the grid to be adjusted.
• An area of greater thickness has a higher retention capacity and higher resistance to flow and an area of lower thickness has a lower retention capacity and lower resistance to flow.
• each second zone has passages having an entrance and an exit offset transversely relative to each other;
• each second zone has a circular outline
• the grid is formed of intersecting grid elements between which the passages are delimited, including at least one grid element of variable height extending in the first zone and at least a second zone, the height of each grid element of variable height being larger in each second zone crossed by the grid element of variable height and smaller in the first zone;
• the grid has a quadrangular contour, in particular a square contour
• the grid has four second zones
• the invention also relates to a nuclear fuel assembly, in particular for a pressurized water nuclear reactor, comprising an anti-debris filter as defined above.
• FIG. 1 is a side view of a nuclear fuel assembly
• FIG. 2 is a sectional view of a lower end of the nuclear fuel assembly of Figure 1, fitted with an anti-debris filter;
• FIG. 3 is a bottom view of the anti-debris filter
• FIG. 4 is a bottom view of a quadrant of the anti-debris filter
• the nuclear fuel rods 4 extend parallel to each other and to a longitudinal axis L.
• the first face 32A of the grid 32 is facing upwards, this first face 32A being in practice facing downwards when the grid 32 is mounted on the lower end 8 and the The nuclear fuel assembly 2 is installed in the core of the nuclear reactor.
• each passage 36 extends between an inlet 36A, located on the first face 32A, and an outlet 36B, located on the second face 32B.
• the inlet 36A of each passage 36 has an input axis A1 and the outlet 36B of each passage 36 has an output axis A2.
• Each passage 36 extends from its inlet 36A to its outlet 36B along a central line C of this passage 36.
• Each passage 36 having a non-zero angle of inclination 0 between its input axis A1 and its output axis A2 preferably has its input 36A and its output 36B offset transversely relative to each other considering the direction of flow of the fluid through the grid 32.
• the grid 32 has passages 36 having angles of inclination 0 between their input axis A1 and their output axis A2 different.
• the grid 32 has passages 36 having different respective deflections.
• the output axes A2 of all passages 36 are parallel to each other, the input axes A1 of passages 36 having different angles of inclination 0 being inclined relative to each other.
• the outlet axes A2 of the passages 36 are parallel to the direction of flow of the fluid. This makes it possible to limit disturbances to the flow of fluid at the outlet of grid 32.
• passages 36 with different inclination angles 0 makes it possible to differentiate the retention capacity and the resistance to flow of different zones of the grid 32.
• a zone of the grid with passages 36 having larger angles of inclination 0 i.e. larger deflections
• a zone of the grid with passages 36 having smaller tilt angles 0 i.e. smaller deflections
• the input axes A1 of passages 36 of each second zone Z2 are for example inclined by a non-zero angle relative to the input axes A1 of the passages 36 of the first zone ZI.
• the input axes A1 of these passages 36 of each second zone Z2 make a non-zero angle with the input axes A1 of the passages 36 of the first zone Z1.
• the angle of inclination 0 between the input axis A1 and the output axis A2 of each passage 36 of the first zone Z1 is for example substantially zero.
• the passages 36 of the first zone Z1 are for example rectilinear.
• the grid 32 has for example four second zones Z2 distributed on the grid 32 of quadrangular and in particular square shape, the second zones Z2 being for example distributed according to a 2X2 matrix distribution.
• Grid 32 here has four second zones Z2, each second zone Z2 being located in a respective quadrant of grid 32.
• the grid 32 has a thickness strictly greater than the thickness of the grid 32 in the first zone Z1.
• the grid 32 has a substantially constant thickness, called first thickness E1.
• the grid 32 has a second thickness E2 strictly greater than the first thickness E1 of the grid 32.
• each second zone Z2 at least part of the grid elements 38, 40 has a height strictly greater than the first height H1.
• each first grid element 38 or only part of the grid elements 38 has a height greater than the first height H1 and/or each second grid element 40 or only part of the second elements of grid 40 has a height greater than the first height H1.
• each passage 36 are defined by the portions of the grid elements 38, 40 delimiting the passage 36.
• the side walls of the passages located in each second zone Z2 are higher than the side walls of the passages located in the first zone Z1.
• each passage 36 is delimited between two opposite side walls which extend substantially parallel while being curved
• each of these passages 36 extends in a curvilinear manner, its inlet 36A and its outlet 36B being offset transversely with respect to one another and inclined with respect to one another.
• each first grid element 38 of variable height, and in particular each first grid element 38 has an upper portion 42 which extends higher than the rest of the first face 32A of the grid 32 in the first zone Z1.
• each first grid element 38 is for example curved to define the curved passages 36.
• second grid elements 40 of variable height have upper portions 44 which intersect the upper portions 42 of the first grid elements 38 of variable height.
• the input axes A1 of the passages 36 are parallel to each other and the output axes A2 of the passages 36 are parallel to each other.
• the grid blank 32 is machined on its first face 32A so as to form the first zone Z1 and each second zone Z2.
• passages 36 Due to the variation in thickness of the machined grid 32, certain passages 36 are reduced in height, and passages 36 finally have input axes A1 inclined relative to each other.
• the passages 36 located in the thinnest regions of the machined grid 32 have the least inclined input axes A1 and the smallest inclination angles 0, and the passages 36 located in the thickest regions of grid 32 have the most inclined input axes A1 and the largest angles of inclination 0.
• Such a grid 32 is for example obtained by additive manufacturing.
• a passage 36 of variable cross section provided with a converging inlet section 46 and a diverging outlet section 48 without an intermediate section of constant cross section, has for example curved and convex side walls.
• An area of the grid with passages 36 having larger tilt angles 0 has greater debris retention capacity and greater flow resistance, whereas an area of the grid with passages 36 having Smaller tilt angles 0 have smaller debris holding capacity and smaller flow resistance.
• the second zone(s) Z2 can be placed on the grid 30 at the location(s) where the probability of debris passing is greatest, which is most of the time. time with respect to the openings 18 of the lower core plate 16 through which the cooling fluid arrives under the nuclear fuel assemblies 2.
• the grid 30 can be easily manufactured, for example by additive manufacturing and/or by machining.
• the passages 36 of the grid in Figures 4 and 7 are delimited between first curved grid elements 38 and second flat grid elements 40, so that the input axes A1 of the passages 36 are all inclined in the same direction.
• the input axes A1 of the passages 36 are all parallel to the same reference plane.
• the input axes A1 can be parallel if the angles of inclination of the passages 36 are the same or not if the passages have different angles of inclination.
• output axes A2 which are not parallel between two, with in particular output axes A2 which have a non-zero inclination with the longitudinal axis L of the nuclear fuel assembly 2 when the grid 30 is mounted on the lower end 8.
• first zone Z1 having a first thickness E1 and at least a second zone Z2 having a second thickness E2 is advantageous independently of the fact that the passages 36 have angles of non-zero inclination between an input axis A1 and an output axis A2, in particular differentiated inclination angles between different passages 36.
• Each second zone Z2 thicker than the first zone Z1 has a higher retention capacity than the first zone Z1 and a higher flow resistance than the first zone Z1.
• the passages 36 located in each second zone Z2 are a priori longer than the passages 36 located in the second zone Z2, and allow for example longer debris to be filtered.
• first zone Z1 and at least a second zone Z2 thicker than the first zone Z1 makes it possible to locally adapt the retention capacity, depending on the probability of the presence of debris, while limiting the resistance to the flow of the grid 32 as a whole.
• each second zone Z2 has a circular outline.
• the grid 32 is formed of intersecting grid elements 38, 40 between which the passages 36 are delimited, including at least one grid element 38, 40 of variable height extending in the first zone Z1 and at least one second zone Z2, the height of each grid element 38, 40 of variable height being greater in each second zone Z2 crossed by the grid element 38, 40 of variable height and smaller in the first zone Z1;
• - grid 32 has four second zones Z2;
• the second zones Z2 are distributed on the grid 32 in a matrix manner
• the invention also proposes a lower end piece of a nuclear fuel assembly equipped with an anti-debris filter as defined above and/or a nuclear fuel assembly, in particular for a pressurized water nuclear reactor , comprising an anti-debris filter as defined above.
• the grid 32 has, in each cell 50, a plurality of separate passages 36.
• the passages 36 of each cell 50 are separated from each other by side walls or partition walls 54, which are for example intersecting grid elements.
• Each cell 50 in which the grid 32 has a variable thickness, includes passages 36 of different heights.
• the cell 50 includes in particular lower passages 36, located in the first zone Z1, and higher passages 36, located in the second zone Z2.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Structure Of Emergency Protection For Nuclear Reactors (AREA)
• Filtration Of Liquid (AREA)
• Nozzles (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=84820051

Family Applications (1)

Country Status (5)

Family Cites Families (5)

• 2022
  • 2022-10-07 FR FR2210306A patent/FR3140703B1/fr active Active
• 2023
  • 2023-10-03 AR ARP230102645A patent/AR130669A1/es unknown
  • 2023-10-05 EP EP23783891.7A patent/EP4599465A2/de active Pending
  • 2023-10-05 WO PCT/EP2023/077525 patent/WO2024074592A2/fr not_active Ceased
  • 2023-10-05 CN CN202380070392.6A patent/CN119998894A/zh active Pending

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