• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    An improved maintenance and alignment system for nuclear fuel rods having a top nozzle frame and a bottom nozzle frame, nuclear fuel rods (20) each having a top end and a bottom end and extending axially between the upper and lower end frames, a first precision magnet integrated at the lower end of the fuel rod (s) (20), and a plurality of second precision magnets integrated on the frame of bottom nozzle at locations next to first precision magnets on the fuel rods. Each first precision magnet has at least one north or south magnetic polarity and the second precision magnet has at least one south or north magnetic polarity opposite to the polarity of the first precision magnet facing to induce a magnetic attraction between the first and second Precision magnets facing each other. Grids (18) between the upper and lower end frames form cavities (60) through which the fuel rods (20) pass. Precision magnets of the same polarity may be disposed laterally along the fuel rods and the grid walls at opposed locations to repel the fuel rods (20) relative to the grid walls to maintain stability. aligning the fuel rods (20) and preventing contact between the fuel rods (20) and the grids (18).
    公开号:FR3063380A1
    申请号:FR1851630
    申请日:2018-02-26
    公开日:2018-08-31
    发明作者:Nathan J. Payne；Jeffrey M. McCarty
    申请人:Westinghouse Electric Co LLC；
    IPC主号:
    专利说明:

    © Publication number: 3,063,380 (to be used only for reproduction orders)
    ©) National registration number: 18 51630 ® FRENCH REPUBLIC
    NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY
    COURBEVOIE © IntCI 8
    G 21 C 5/06 (2017.01), G 21 C 3/12
    PATENT INVENTION APPLICATION
    A1
    ©) Date of filing: 26.02.18. (Tl) Applicant (s): Westinghouse Electric company llc (30) Priority: 14.02.18 US 15896473; 02.28.17 US 62464457. - us. (© Inventor (s): payne nathan j. And mccarty jeffrey m .. ©) Date of public availability of the request: 31.08.18 Bulletin 18/35. ©) List of documents cited in the report preliminary research: The latter was not established on the date of publication of the request. (© References to other national documents ©) Holder (s): Westinghouse Electric company llc. related: ©) Extension request (s): ® Agent (s): casalonga.
    PRECISION THREE-DIMENSIONAL PRINTED MAGNETS FOR FUEL ASSEMBLY.
    FR 3 063 380 - A1
    Improved holding and alignment system for nuclear fuel rods, comprising an upper nozzle frame and a lower nozzle frame, nuclear fuel rods (20) each having an upper end and a lower end and are extending axially between the upper and lower nozzle frames, a first precision magnet integrated into the lower end of the fuel rod (s) (20), and a plurality of second precision magnets integrated into the frame lower nozzle at locations opposite the first precision magnets on the fuel rods. Each first precision magnet has at least one north or south magnetic polarity and the second precision magnet has at least one south or north magnetic polarity opposite to the polarity of the first precision magnet facing to induce a magnetic attraction between the first and second precision magnets facing each other. Grids (18) between the upper and lower nozzle frames form cells (60) through which the fuel rods (20) pass. Precision magnets of the same polarity can be arranged laterally along the fuel rods and the walls of the grids at locations opposite each other to push the fuel rods (20) relative to the walls of the grids in order to keep the alignment of the fuel rods (20) and preventing contact between the fuel rods (20) and the grids (18).

    i
    Precision three-dimensional printed magnets for fuel assembly
    The present invention relates to holding systems for nuclear fuel rods and, more particularly, magnetic holding systems.
    In conventional nuclear reactor systems, the fuel rods are held in place axially and laterally using mechanical parts such as springs, spacers, plugs and other devices arranged along and at each end of a rod of fuel. These conventional means of maintaining and aligning are installed at the expense of the pressure in the system without bringing a corresponding advantage as to thermal efficiency. The circulation of heat transfer fluid around the fuel rods and on the mechanical holding and alignment parts reduces the pressure of the heat transfer fluid, which causes a pressure drop in the flow of heat transfer fluid.
    In addition, the holding and alignment pieces are liable to cause wear of the fuel rods due to the contact between the mechanical holding devices and the fuel, which is liable to cause damage to the fuel rods.
    Removing these holding and aligning devices that create contacts would suppress or reduce the pressure drop in the coolant. Avoiding pressure loss would improve fuel efficiency.
    The problems associated with holding and aligning devices operating by physical contact are resolved by the holding and aligning system of nuclear fuel rods described here, the holding being obtained by magnetizing certain contacts between adjacent parts. Magnetization can be obtained using precision magnets that match the polarity of opposite magnets.
    An improved holding and alignment system for nuclear fuel rods may, in various aspects, include an upper tip frame and a lower tip frame, at least one nuclear fuel rod having an upper end and a lower end and extending axially between the upper and lower ends, a first precision magnet integrated into the lower end of the at least one fuel rod, and a second precision magnet integrated into the lower end frame at a facing location at least a first precision magnet. The first precision magnet has at least one north or south magnetic polarity and the second precision magnet has at least one south or north magnetic polarity opposite the polarity of the first precision magnet facing to induce a magnetic attraction between the first and second precision magnets facing each other.
    According to various aspects, a first precision magnet is integrated at the lower end of the at least one fuel rod and a second precision magnet is integrated on the lower end piece in order to retain the fuel rod axially, by magnetic attraction, between the upper and lower end caps.
    According to various aspects of the system, each of the at least first and second precision magnets has at least one, and in some aspects at least two, matched sections. Each paired section has a polarity opposite to that of the other section of the pair. The paired sections may be in a locked configuration in which the facing precision magnet sections attract each other to an unlocked configuration in which the facing precision magnet sections repel each other. 'one another.
    In various aspects, the polarity of each member of the pair can be selectively caused, for example by rotation, to change to the opposite polarity to selectively switch one of the first and second precision magnets from the locked configuration to the unlocked configuration. According to various aspects of the system, the paired sections of the at least first and second precision magnets can be rotatable to rotate the paired sections of one of the first and second precision magnets to put them in the locked or unlocked configuration.
    The improved maintenance and alignment system can solve problems of maintaining alignment of fuel rods during seismic phenomena. The system may include at least one grid substantially parallel to the upper and lower end pieces and placed between the latter. The at least one grid defines a perimeter and has, inside the perimeter, a first set of plates extending laterally and longitudinally from one side to the other of the grid to define at least one cell and, according to some aspects, multiple alveoli. Each cell has an interior and an exterior, at least one fuel rod passing axially through the interior of a cell. The walls of the grid plates can include at least a third precision magnet integrated inside the cell. At least a fourth precision magnet can be integrated on one side of the fuel rod, on the sheath of the fuel rod or on a sleeve enveloping the fuel rod, at a location opposite the at least third precision magnet. The third precision magnet has at least a north magnetic polarity or a south magnetic polarity and the fourth precision magnet has at least a north magnetic polarity or a south magnetic polarity identical to the polarity of the third precision magnet located opposite to create a magnetic repulsion between the third and fourth precision magnets facing each other to maintain a gap between the fuel rod and the plate on which the third precision magnet facing is integrated.
    In some aspects, the system may have a plurality of cells and a plurality of fuel rods, each cell having dimensions to accommodate one of the plurality of fuel rods, extending therethrough.
    According to various aspects, each housing through which a fuel rod passes has at least two third precision magnets integrated on different walls of grid plates and the fuel rod (or its sheath or sleeve) has at least two fourth magnets precision. Each fourth precision magnet is placed on the fuel rod to be opposite one, different, of at least two third precision magnets integrated on the walls of the grid plates.
    The invention will be better understood on detailed study of a few embodiments taken by way of nonlimiting examples and illustrated by the appended drawings in which:
    FIG. 1 is a schematic cutaway perspective view of some of the parts of a conventional fuel assembly, representing an assembly of fuel rods, an upper nozzle, several layers of grids, a lower nozzle, fuel rods and sleeves grid;
    FIG. 2 illustrates the difference between the magnetic field lines in a conventional magnet A and a precision magnet B, representing the loss suffered with conventional magnets;
    FIG. 3 is a view of precision magnets according to the prior art, with a printed combination of locking / resistance, representing positive and negative poles distributed over the surface of the magnets;
    FIG. 4 is a view of the magnetic fields visible under a magnetic film, representing combinations of positive and negative poles on the surface of discs according to the prior art;
    FIG. 5 represents (A) a fuel rod end on which are matched sections of precision magnets, and (B) a lower frame provided with a holding element comprising matched sections of precision magnets of opposite polarity to that of the facing fuel rod sections printed thereon for magnetically retaining the fuel rod of Figure 5A;
    FIG. 6 is a view of the end of the fuel rod of FIG. 5A assembled with the precision magnet holding element of FIG. 5B in a locked position where the facing sections have the opposite polarity;
    FIG. 7 is a view of the fuel rod and precision magnet holding element of FIG. 6 in an unlocked position where the facing sections have the same polarity;
    FIG. 8 is a perspective view of another possible embodiment of a part of a lower frame representing precision magnet contacts printed with a plug for cooperation with a precision magnet at the end d 'a fuel rod of Figure 5A;
    FIG. 9 is a partial view of an embodiment of a grid plate wall for a fuel rod, representing precision magnets printed on the outside of a grid plate wall to create resistance to impacts between adjacent surfaces of grid plates at a desired interval;
    FIG. 10 is a partial perspective view of adjacent walls of the grid plates of FIG. 9, showing precision magnets on the external surface of each wall of the grid plate;
    FIG. 11 is a top plan view of fuel rods in an embodiment of a fuel assembly, representing precision magnets as well as bosses. Stabilization for the lateral positioning of the fuel rods;
    FIG. 12 is a perspective view of the assembly of fuel rods in FIG. 11;
    FIG. 13 is a top plan view of fuel rods in another possible embodiment of a grid assembly representing only precision magnets inside the housing and the fuel rod for positioning side of the fuel rods; and
    FIG. 14 is a perspective view of the assembly of fuel rods in FIG. 13.
    The directional vocabulary used here, in particular, by way of nonlimiting examples, top, bottom, left, right, bottom, top, front, back and the variants thereof, will relate to the orientation of the elements represented on the appended drawings and, unless expressly stated otherwise, is in no way limitative as to the claims.
    An example of a system 10 of fuel rods and of a nuclear reactor coolant is partially shown in FIG. 1. The system 10 comprises an assembly 12 of control rods disposed at the upper end of the system 10, an upper end piece 14 with leaf springs 16, an upper end frame 28, a lower end 22, a lower end frame 30 and a plurality of grids 68, 88 and 18 placed between the upper and lower end frames 28, 30 for supporting rows fuel rods 20 extending between the frames 28, 30 of upper and lower tips. The plurality of grids 68, 88 and 18 are substantially parallel to one another but separated from each other and are supported by support bars 24, sometimes called guide tubes, arranged inside the perimeter of the grids and at the l inside several rows of fuel rods 20. The cutaway sectional views of FIG. 1 represent a combination of holes 26 passing through three grids, namely an upper grid 68, an intermediate grid 88 and a lower grid 18, through which the fuel rods 20 pass from the lower end frame 30 to the upper end frame 28. The holes 26 have dimensions established to allow a heat transfer fluid to circulate around the fuel rods 20. Additional openings, for example venturi openings, can be formed in the frames 28, 30 of upper and lower end pieces. The system 10 is housed in a reactor enclosure (not shown).
    As indicated above, in conventional nuclear reactor systems, the fuel rods 20 are held in place laterally by springs 48 and / or bosses 58 on the internal faces of the grids 68, 88 and 18. In a typical system according to In the prior art, each cell has two springs and two bosses. The bosses and the springs are each curved towards the inside of the cell from the wall of the grate plates, forming protruding parts 56 intended to come into contact with the fuel rod 20. The most flexible spring 48 pushes the fuel rod against the protruding part 56 of the boss 58 in order to immobilize the rod laterally in the cell. The circulation of heat transfer fluid around the fuel rods 20 passing through the springs 48 and other holding devices to hold the fuel rods 20 and the supports 24 in place reduces the pressure of the heat transfer fluid, which causes a pressure drop in the heat transfer stream.
    In the holding system described here, the fuel rods 20 are held in place by means of matching combinations of precision magnets, facing each other. The methods of axial and lateral holding of fuel rods described here offer the possibility of eliminating parts, reducing the pressure drop mentioned above and limiting the problems due to friction (eg reducing or eliminating the wear of the fuel rods due to contact with mechanical grate holding devices). By incorporating means for absorbing or preventing shock of adjacent fuel assemblies against devices of grids 68, 88 and 18, the improved holding and alignment system will reduce the seismic forces acting on the fuel assemblies and will reduce, and preferably eliminate the risk of accidents due to loss of associated coolant. The improved holding and alignment system will also prevent take-off of fuel assemblies at the axial holding devices and allow for simplified removal of parts for reconstitution, repair or replacement.
    Precision magnets are fundamentally different from conventional magnets. Most conventional commercial magnets have a simple configuration: a north pole on one side and a south pole on the other. Magnets controlled by software, such as those sold under the brand POLYMAGNETS ® by Correlated
    Magnetics Research LLC of California, USA, which have been developed on a commercial scale, allow the realization of adaptable magnetism combinations designed by software and programmed in a magnet. See, for example, US patents 8,179,219, US 9,219,403, US 9,245,677 and US 9,404,776. These precision magnets can be up to five times stronger than conventional magnets, as their magnetic energy can be concentrated near the surface, as shown in Figure 2. The technology of 3D printed precision magnets is an emerging field which prints individual magnetic poles (digital / pixelated) giving them an adaptable 3D orientation and geometry. This ability to print small field magnetic circuits allows increased magnetic forces over a shorter distance due to the less energy loss from the field. The conventional magnets 206, 208 shown in Figure 2A do not necessarily align when attached to each other. The magnetic field lines 210 of the conventional magnets 206, 208 show that a large part of the magnetic energy is lost, diverted from the magnets 206, 208. The precision magnets, as shown in Figure 2B, concentrate the magnetic field. In the precision magnets 202, 204, the magnetic field lines 210 form a smaller, narrower field, so that the magnetic force does not escape from the magnets.
    Precision magnets such as those marketed under the POLYMAGNETS ® brand can be designed to align with all kinds of alignment functions. Precision locking magnets, for example, are designed to repel each other until the pair of magnets passes through a defined transition point. After the transition point, they are designed to reverse their polarity and attract each other. Precision spring magnets are designed to attract themselves to a transition point beyond which they repel. These precision magnets stop at an equilibrium distance. At equilibrium, the opposite precision magnets remain at a predetermined distance from each other, so that the parts in which the precision magnets are placed can be kept separated, spaced from each other by the predetermined distance or so.
    Considering Figures 3 and 4, alternative configuration of precision magnets are shown by way of illustration. In Figure 3 are shown two opposing discs 200 having, on each disc, a plurality of precision magnets matching the precision magnets of the facing disc. Precision magnets with, for example, a north magnetic pole 202 are indicated by a plus sign and precision magnets with a south magnetic pole 204 are indicated by a negative sign. When discs A and B are brought together, they can be aligned so that the north (+) poles of disc A align directly with the south (-) poles of disc B and the South (-) poles of disk A align with the North (+) poles of disk B, forcing disks A and B to attract and come together. Due to the narrow magnetic field, as shown in Figure 2B, the force of attraction between the discs A and B is very strong. If it is necessary or desirable to cause the two discs 200 to repel each other, the precision magnets 202, 204, on the discs 200 can be aligned so that the north (+) and south (-) poles of the disc A align respectively with the north (+) and south () poles of the disk B. The identical magnetic poles on opposite disks repel each other, moving the disks A and B apart from each other. In Figure 3, an image of two discs 200 placed side by side shows the magnetic fields of the discs through an envelope 300. The disc on the right in the image has precision magnets having poles (+) 202 on the outer ring and magnets of precision at poles (-) 204 in central crown. The disc 200 on the left in the image has precision magnets 202, 204 alternating north (+) and south (-) poles respectively. Figures 3 and 4 illustrate the possible geometries and combinations that can be used to configure holding assemblies with precision magnets.
    Opposite matching precision magnets for use in the environment of a nuclear fuel and heat transfer system 10 may be of any suitable material which is believed to retain its magnetic properties under the conditions prevailing in a reactor. Research has shown that certain materials, such as Sm 2 Coi7, have an interesting resistance to temperature and irradiation with regard to the degradation of magnetic properties.
    The possibility of axially immobilizing and keeping aligned the fuel rods 20 using a method without lateral contacts, in particular using precision magnets, can make it possible to remove the lower grid 88 and should significantly reduce the problems due to pressure drops in current fuel assemblies. The holding geometries can be magnetically locked to allow easy reconstitution of the fuel rods 20.
    Considering Figure 5A, there is shown a variant of the conventional type of cap 32 of a fuel rod 20. The cap 32 comprises a protuberance 38 welded to one end or to both ends of a fuel rod (not shown on this view). An end surface 34, for example on the lower plug 32 can, according to various aspects, have first precision magnets 36 integrated in the surface 34. The first magnets can be a single magnet with a single polarity. According to certain aspects, the first magnet can comprise paired sections with positive and / or negative polarity, as in the alternating combination of positive (+) 202 and negative (-) 204 poles represented on the surface 34.
    Figure 5B shows the lower frame 30 comprising a plurality of holes 42 for the passage of a reactor coolant such as water around the fuel rods 20, and feet 44 for supporting the lower frame 30. The lower frame 30 further comprises a second precision magnet 40 integrated therein for each fuel rod 20 for its alignment with the first precision magnet 36 on the end surface 34 of the plug 32 of the fuel rod 20. The second precision magnet 40 can be a single magnet with a single polarity opposite to the polarity of the first ll single magnet 36 or can comprise matched sections with a single polarity or with two polarities, positive and negative, as shown in FIG. 5B, which can be arranged or programmed so that the polarity of the sections matched on the surface 34 is opposite to the polarity of the sections present on the frame 30. The second has precision imant 40 includes an alternation of positive (+) 202 and negative (-) 204 poles which, when aligned in an orientation opposite to that of the poles of the first precision magnet 36 on the end surface 34, have a strong magnetic attraction, immobilizing the fuel rod 20 in the lower frame 30 when the two are brought into contact with each other, as shown in Figure 6. In various aspects, a similar end surface with a precision magnet 36 can be integrated into the upper end of the fuel rod 20 for its magnetic attachment to a corresponding precision magnet 40 integrated in the upper frame 28. The precision magnets at the lower end of the fuel rods 20 being opposite the lower frame 30, the fuel rods 20 can be locked with an axial alignment in the reactor system 10. When it is necessary to move a fuel rod 20, for example to reconstitute, replace or restore it, one of the first and second precision magnets 36, 40 is rotated at the end of the fuel rod 20 to place the positive (+) and negative (-) poles 202, 204 of a precision magnet 36 or 40 in alignment with the same poles of the opposite precision element 40 or 36 so that the surfaces of lower ends of the fuel rod (or of the fuel rod cap) and of the associated frame 30 repel each other by moving to the unlocking position, as shown in FIG. 7.
    In some aspects, each of the first and second precision magnets 36, 40 may be made of a plurality of matched sections, each section of a pair may have the same polarity as the other section of the pair or each section of a pair which may have the opposite polarity of the other section of the pair. The polarity of each section can be selectively caused to change to the opposite polarity to selectively pass one of the first and second precision magnets 36, 40 of the latching configuration, in which at least a majority of the magnet sections precision facing attract each other to an unlocked position in which at least a majority of the facing precision magnet sections repel each other. In this embodiment, the power of the attraction or repulsion force can be controlled by the polarity of sections of the precision magnets facing each other.
    According to another aspect, as shown in FIG. 8, a second precision magnet 40 can be placed by suitable means, for example by 3D printing, in each of the different spaced depressions 46 present in a lower frame 30 ′, holes 42 also being formed in the lower frame 30 ′ for the circulation of the coolant around each fuel rod 20. According to certain aspects, the frame 30 ′ may have a structure of the alveolar type constituted by the plurality of depressions 46 and holes 42 of circulation of coolant. Each of said depressions 46 is designed to receive the cap 32 of a pencil from among the plurality of fuel rods 20. The plurality of depressions 46 may comprise a bottom, on which is integrated a second precision magnet 40 and, around the bottom, openings which open into openings of the venturi type just under the depression 46 for the circulation of the coolant. The circulation holes 42 can also form openings of the venturi effect type. In use, the first precision magnet 36 on the end surface 34 of each plug 32 is arranged to align with the precision magnet 40 at the bottom of the depression 46 so that they attract or repel each other. 'the other respectively to lock or unlock the fuel rod 20 relative to the frame 30'. As described above, the precision magnets 36, 40 may have matched sections of alternating combinations of positive (+) 202 and negative (-) 204 poles on each of the precision magnets, which can be rotated to take alignment causing an attraction or a repulsion, or each can have a single positive (+) 202 or negative (-) 204 pole on one magnet and a single negative (-) 204 or positive (+) 202 pole on the other magnet, polarity opposite to that of the facing precision magnet, so that they attract each other in order to axially lock the fuel rod 20 in the depression 46. Unlocking can be carried out by reversing the polarity of one of the two precision magnets facing each other, for example by rotating the fuel rod.
    A grid according to the prior art comprises laterally disposed grid plates 50 which intersect within the perimeter of the grid to define cells 60 through which the fuel rods 20 pass. The grid plates 50 serve to laterally align the fuel rods 20 and to prevent adjacent fuel rods 20 from coming into contact with each other. The grid plates 50 may comprise springs 48 An embodiment of examples of springs 48 is shown in FIGS. 9 and 10. Each cell 60 may comprise one or two springs 48, on different sides of the grid plate sections which define the cell 60. In various embodiments, each cell can include two springs 48 or two bosses 58. The springs 48 or the bosses 58 extend or curve from the grid plate wall into the cell 60 by forming a projecting plate 56 which inclines towards the fuel rod 20 when the pencil is placed in the cell 60 so that the projecting plate 56 of the spring 48 is pressed or wedged laterally against the adjacent fuel rod 20 The springs 48 can be arranged so that at least two plates 56 extend into each cell 60 to immobilize the rod 20 laterally in the cell 60.
    In some aspects, when there are adjacent fuel assemblies 10, the design of the grids may include a first set of grate plates 50 around the periphery of a first fuel assembly 10 and a second set of grate plates around the periphery of the adjacent fuel assembly 10 on each grate 68, 88 and 18. The second set of grate plates 52 is arranged in the immediate vicinity of the first set of grate plates 50 so as to define a space between the walls of grate plates adjacent 50, 52. The walls of adjacent grid plates are located in substantially parallel planes and spaced from each other.
    According to certain aspects, illustrated in FIGS. 9 and 10, precision magnets 361 and 401, corresponding to precision magnets 362 and 402, can be integrated in the external surfaces of adjacent grid plates 50, 52 of the first and second sets to absorb side impact to maintain a distance between adjacent fuel assemblies 10. An innovative design of grids for accident tolerant fuel configurations can add one or both sets of precision magnets 361, 362 and 401, 402 , by integrating them into the external surface of the plates 50, 52 of grids during the manufacturing process. The fabrication of the grid plates 50, 52 can be done, for example, by any known suitable 3D printing process or by any other process to form an article or a three-dimensional molded surface. Combinations of precision magnets can be printed, for example, in adjacent areas of the grid plates 50, 52 to create resistance, at a predetermined distance or interval 54 between the outer faces of the adjacent grid plates 50, 52 The intervals 54 reduce the force of seismic accidents and loss of heat transfer fluid without requiring, on the grate plates, external devices which risk causing damage to the fuel rods 20 held in the cells 60 in the event of unforeseen movement of n no matter what significant force. When each aligned pole 202 or 204 of the opposite precision magnets, respectively 361, 362 and 401, 402, is of the same polarity, the plates 50, 52 of grids repel and resist impact. Controlling the power of the magnetic field generated by the precision magnets 361, 362, 401 and / or 402 makes it possible to control and maintain, under difficult circumstances, the distance 54 between the exteriors of the adjacent grid plates 50, 52.
    Considering FIGS. 11 and 12, there is shown another possible configuration of lateral arrangement of fuel rods which incorporates precision magnets 72 inside the cells 60 and precision magnets facing 70 on the fuel rods 20 Combinations of precision magnets can be integrated into the internal face of the walls 50 of grate plates in place of or in addition to the bosses 58, which align the fuel rods 20 in the cells 60 of the grids. A thin sleeve 62 can be fixed to the fuel rod 20. On the sleeve 62 can, according to various aspects, be printed the magnetic pole opposite the pole integrated in the grid plate 50 at some or all of the grids 68, 18, 88 in the system 10. The repulsion force of the magnets of precision with identical polarity opposite (that is to say of each of the magnets of precision opposite having positive poles (+) 202 or of each of the magnets precision facing with negative poles (-) 204) maintains a desired gap 74 between the fuel rod 20 and a sleeve covering the rods 20. This arrangement provides a large margin against friction between the grids and the rods, because it will require much less (if at all) supports 24 to avoid contact between pencils 20.
    Considering FIG. 11, there are represented cells 60 defined by plates 50 of grids arranged differently from grid plates described above and represented in FIG. 10. Each · cell 60 also comprises mixing fins 78 for controlling the circulation of the coolant around the fuel rods 20. The flow of coolant circulates parallel to the rods 20.
    In certain aspects, illustrated in FIGS. 13 and 14, the bosses 58 can be omitted as holding means in the cells 60, so that the precision magnets 72 inside the grid plates 50 and the magnets of precision 70 on the pencil 20 or a pencil sleeve 62 constitute the only means of maintaining the separation, the interval 74, between the pencils 20 and the plates 50 of grids in each cell 60.
    Costs can be reduced significantly by combining and removing parts. Parts can be ordered more easily and allow cost savings by eliminating tight tolerances such as springs and bosses in sheet metal parts. There will be less pressure drop in the coolant flow, which will result in improved fuel efficiency and more combustion. Movements between fuel assemblies and fuel rods likely to occur in the event of an accident can be better controlled, which avoids damage due to sudden impacts between adjacent parts. The use of precision magnets to maintain the lateral position of the pencils ensures contactless support. This provides greater spacing between the fuel rods and other parts, which limits wear and tear since debris will not be trapped against the fuel rods.
    The improved holding devices described here create possibilities for simplifying organs and, what is important, creating safer fuel designs for use in places with the highest seismicity.
    The present invention has been described with reference to several examples, intended in all their aspects to serve as non-restrictive illustrations. Thus, the detailed implementation of the present invention lends itself to numerous variants which can be derived from the present description by an ordinary specialist in the art.
    List of landmarks
    10 Fuel rod and coolant system Fuel rod set 12 5 14 Upper end cap 16 Leaf springs 18 Lower grid 20 Fuel rods 22 Bottom end 10 24 Support bars / Guide tubes 26 Holes in the grids 28 Top end frame 30/30 ' Bottom end frame 30 / Figures 6-7 and other plate lower end cap possible 30 '/ Figure 8 IS 32 Plug 34 End surface on plug 36 First precision magnets 38 Protrusion on cap 40 Second precision magnet 20 42 Holes in bottom end frame 30 44 Feet on lower end frame 46 Depressions on the lower end frame 48 Springs 50 First set of grid plates 25 52 Second set of grid plates 54 Interval between external faces of plates of adjacent grids 50, 52 56 Protruding plate surfaces on springs 48 and bosses 58 extending into cells 30 58 Bosses 60 Alveoli 62 Sleeve on fuel rod 68 Upper grid 70 Precision magnets on fuel rod 20
    Precision magnets inside plates 50 of grids Interval between pencils 20 and plates 50 of grids in the cells 60
    Mixing fins in the cells 60
    Intermediate grid
    Opposite discs
    Precision magnet with north magnetic pole
    Precision magnet with south magnetic pole
    Classic magnet in Figure 2A
    Classic magnet in Figure 2A
    Magnetic field figures
    Envelope in Figure 3
    Precision magnets matching 362 magnets / Figures 9 & 10
    Precision magnets matching magnets
    361 / Figure 10
    Precision magnets matching magnets 402 / Figures 9 & 10
    Precision magnets matching 401 magnets / Figure 10
    权利要求:
    Claims (14)
    [1]
    1. Holding and alignment system (10) for nuclear fuel rods (20), comprising;
    an upper end frame (28) and a lower end frame (30);
    at least one nuclear fuel rod (20) having an upper end and a lower end and extending axially between the frames (28, 30) of upper and lower tips (14, 22), at least a first precision magnet (36) integrated at the lower end of the at least one fuel rod (20); and at least one second precision magnet (40) integrated on the lower end frame (30) at a location opposite the at least one first precision magnet (36), the first precision magnet (36) having at least a north or south magnetic polarity and the second precision magnet (40) having at least one south or north magnetic polarity opposite the polarity of the first precision magnet (36) facing each other to induce a magnetic attraction between the first and second magnets precision (36, 40) opposite one another.
    [2]
    2. System (10) according to claim 1, in which each of the at least first and second precision magnets (36, 40) has at least one paired section, each section of the pair having a polarity opposite to the polarity of the another section of the pair, the polarity of each section of the pair being selectively movable to the opposite polarity to selectively shift one of the first and second precision magnets (36, 40) from a locked configuration in which the facing precision magnet sections attract each other to an unlocked configuration in which the facing precision magnet sections repel each other.
    [3]
    The system (10) according to claim 2, wherein each of the at least first and second precision magnets (36, 40) has at least one second paired section, each second paired section having a polarity opposite to the polarity of the another second paired section, and the polarity of the paired sections being changed by rotation of one of the first and second precision magnets (36, 40) to place the second paired section of a section of one of the first and second precision magnets opposite the first section paired with the other of the first and second precision magnets so that the opposite sections have the same polarity.
    [4]
    4. The system (10) according to claim 1, in which each of the at least first and second precision magnets (36, 40) has at least one paired section, each section of the pair having a polarity identical to the polarity of the another section of the pair, the polarity of each section of the pair being selectively movable to the opposite polarity to selectively shift one of the first and second precision magnets (36, 40) from a locked configuration in which the facing precision magnet sections attract each other to an unlocked configuration in which the facing precision magnet sections repel each other.
    [5]
    5. The system (10) according to claim 4, wherein each of the at least first and second precision magnets (36, 40) has at least one second paired section, each second paired section having a polarity identical to the polarity of the another second paired section, and the polarity of the paired sections being changed by rotation of one of the first and second precision magnets (36, 40) to place the second paired section of a section of one of the first and second precision magnets facing the first matched section of the other of the first and second precision magnets such that the opposite sections have opposite polarity.
    [6]
    The system (10) of claim 1, wherein each of the at least first and second precision magnets (36, 40) each has at least one paired section, each section of a pair of the plurality of paired sections having either the same polarity as the other section of the pake is an opposite polarity to that of the other section of the pair, the polarity of each section can be selectively caused to pass to the opposite polarity to selectively pass one of the first and second precision magnets (36, 40) of a locked configuration in which at least a majority of the facing precision magnet sections attract each other to an unlocked configuration in which at least the majority of sections of facing magnets repel each other.
    [7]
    7. System (10) according to claim 6, in which the polarity of each section can be selectively brought to pass to the opposite polarity by rotation of at least a first and second precision magnets (36, 40).
    S. System (10) according to claim 1, in which a first precision magnet (36) is integrated at the lower end of at least one fuel rod (20) and a second precision magnet (40) is integrated in the lower end frame (30) for axially retaining the fuel rod (20) between the upper and lower end pieces (14, 22).
    [8]
    9. System (10) according to claim 1, further comprising at least one grid (68, 88, 18) substantially parallel to the upper and lower end pieces (14, 22) and placed between the latter, the at least one grid defining a perimeter and having, inside the perimeter, a set of plates (50, 52) extending laterally and longitudinally from one side to the other of the grid (68, 88, 18) to define at least one cell (60) having an interior and an exterior, the at least one cell being designed to receive a fuel rod (20) passing axially through the interior of the cell (60);
    at least a third precision magnet integrated inside the cell (60);
    at least a fourth precision magnet integrated on one side of the fuel rod 20) passing through the cell (60) at a location opposite the at least one third precision magnet, the third precision magnet having a north magnetic polarity and / or a south magnetic polarity and the fourth precision magnet having a north magnetic polarity and / or a south magnetic polarity identical to the polarity of the third precision magnet located opposite so as to create a magnetic repulsion between the third and fourth magnets precision facing each other to maintain a gap between the fuel rod (20) and the grid plate (50, 52) on which is integrated the third precision magnet facing.
    [9]
    10. The system (10) according to claim 9, in which there are a plurality of cells (60) and a plurality of fuel rods (20), a single fuel rod (20) extending axially through the 'any of the cells (60).
    [10]
    11. The system (10) according to claim 10, in which each cell (60) through which a fuel rod (20) passes has at least two third precision magnets integrated on different grate plates of the cell (60) and the fuel rod (20) has at least two fourth precision magnets, each fourth precision magnet being arranged on the fuel rod (20) so as to be opposite one, different, of the at least two third magnets of precision integrated on the grate plates (50, 52).
    [11]
    12. System (10) according to 1 claim 9, further comprising at least one holding element disposed in each cell (60) in order to maintain a gap between the fuel rod (20) and at least one plate (50, 52) of grid of the cell.
    [12]
    13. The system (10) according to claim 1, in which the lower end piece (22) comprises a plurality of cup parts for accommodating the lower end of a fuel rod (20), and each cup part having a first precision magnet (36) integrated therein.
    [13]
    14. System (10) according to claim 1 further comprising a path for the circulation of a coolant along the rod / each of the fuel rods (20).
    [14]
    15. The system (10) according to claim 14, further comprising the fact that the path defines an opening through the grate (s) (68, 88, 18).
    1/12
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    同族专利:
    公开号 | 公开日
    US20180254112A1|2018-09-06|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US10720246B2|2017-04-20|2020-07-21|Westinghouse Electric Company Llc|Fuel assembly arrangement for retaining fuel rod end plug to bottom nozzle|
    CN113362972A|2021-06-04|2021-09-07|中国核动力研究设计院|Fuel rod positioning structure and fuel assembly for overcoming field force repulsion of fuel rod abrasion|
    法律状态:
    2020-01-24| PLFP| Fee payment|Year of fee payment: 3 |
    2021-05-11| PLFP| Fee payment|Year of fee payment: 4 |
    2021-08-20| PLSC| Publication of the preliminary search report|Effective date: 20210820 |
    2022-02-21| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    US201762464457P| true| 2017-02-28|2017-02-28|
    US62464457|2017-02-28|
    US15896473|2018-02-14|
    US15/896,473|US20180254112A1|2017-02-28|2018-02-14|Three dimensional printed precision magnets for fuel assembly|
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