JP3976654B2 - Nuclear fuel assembly separator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  In the present invention, when a known nuclear fuel assembly in which a large number of fuel rods are vertically mounted by spacers is transported, the fuel rod cladding tube is brought into contact with the spacer spring by unintentional external vibration. In order to prevent fretting in the fuel cell and that the spacer spring is subjected to an excessive load due to the vibration external pressure by the cladding tube, thereby causing plastic deformation, the fuel rod is inserted into the nuclear fuel assembly from the outer peripheral side. The present invention relates to a nuclear fuel assembly separator that is inserted and used so as to be detachable.
[0002]
[Prior art]
[Patent Literature]1]
JP-A-8-201574
[Patent Literature]2]
Japanese Utility Model Publication No. 6-40899
[0003]
  A separator for transportation used in a conventional nuclear fuel assembly for a boiling water reactor (BWR) is provided with only a pair of side frame plates A formed in a U-shape as shown in FIG. From a, in parallel with the pair of short side plates b, b, a plurality of elastic contact bending lattice plates c are erected orthogonally so as to be inserted and held in the fuel rod gap. Then, by fitting and sandwiching the pair of side frame plates A and A from the outside of the nuclear fuel assembly so as to face each other, the outer periphery of the nuclear fuel assembly that is in a square shape is inserted. In addition, it is used by being mounted so that it can be fitted. In this case, as understood from (A) and (B) of the same figure, the above-mentioned bent grid plate c for ball contact is a thin plate bent in a zigzag shape as shown in the waveform, As a matter of course, the bending width length d1 of the elastic contact bending lattice plate c is formed to be equal to or slightly wider (d1> d2) than the gap length d2 of the fuel rod e, and the fuel rod gap In this state, the elasticity is exhibited in a state where the elastic contact bending lattice plate c is inserted into the side frame plates A and A and the elastic contact bending lattice plate c. A synthetic resin such as polyethylene that is softer than the stick is adopted.
[0004]
  Further, as in the prior art, the nuclear fuel assembly in which the above-described separator for transporting nuclear fuel assemblies is fitted and mounted as described above is transported in a state where these are further stored in a dedicated transport container. A synthetic resin plate made of polyethylene or the like is attached to the inner surface of the transport container. As for this synthetic resin plate, based on the current situation in which two types of nuclear fuel assemblies for BWR with different external dimensions and fuel rod gap lengths (fuel rod pitch) are used, By utilizing the characteristics of the elastic deformation possessed, the fuel assemblies of both the above and the small sizes can be accommodated by absorbing the dimensional difference only with a fixed transport container of a certain size.
[0005]
  However, in recent years, the MOX (Mixed Oxide) fuel obtained by mixing plutonium extracted by reprocessing spent fuel with uranium is formed and processed, and the pull thermal plan used in ordinary light water reactors is being put into practical use. is there. This pull thermal uses a fuel assembly that has almost the same structure as the current light water reactor fuel, and replaces only the fuel pellets with MOX pellets. It is a good idea to use the synthetic resin used for the nuclear fuel assembly.
[0006]
  However, in the above-mentioned MOX nuclear fuel assembly, the amount of heat generated by the decay of plutonium is larger than that of the current uranium nuclear fuel assembly, and the cask used for transporting the MOX nuclear fuel assembly is shielded or not. Because of the criticality, the surface temperature of the MOX fuel rods is 150 ° C to 200 ° C during transportation because it is larger than the dedicated transport container used for the above-mentioned nuclear fuel assemblies and has a large amount of packing, so heat conduction is poor. It is predicted to rise to the extent. Therefore, in the environment of the above-described temperature rise state, the synthetic resin material forming the current transport separator may be softened and further dissolved, and as a result, the vibration described above is the purpose of the transport separator. Therefore, it is impossible to expect that the spacer ring is protected from plastic deformation, and therefore it is necessary to use a metal material instead of a synthetic resin material.
[0007]
  Not only that, but also for the transport container, the synthetic resin material that is elastic like the current one is affixed to the inner surface, and both large and small sized nuclear fuel assemblies can also be used as a kind of transport container. Cannot be realized because it is unusable. Accordingly, in order to solve this problem, for example, as shown in FIG. 7B, a rectangular cylinder-shaped fuel holder B is constituted by a pair of split holders B1 and B2 having an L-shaped cross-sectional shape that can be opened and closed by a corner hinge f. The side surface of the separator for transportation inserted into the MOX nuclear fuel assembly is held directly on the inner surface or through the silicon rubber plate g which is a heat-resistant buffer, and the holding state is held at a plurality of positions in the axial direction. It is being considered to secure the cask with a load.
[0008]
  However, when the fuel holder B is used as described above, two types of fuel holders B respectively aligned with the nuclear fuel assemblies having large and small dimensional differences as described above are prepared separately, or the silicon rubber plate g It becomes necessary to change only the wall thickness.
[0009]
  Furthermore, as mentioned above, the MOX fuel rods have higher radioactivity than the current uranium fuel rods, so it is required to be automated as much as possible from the viewpoint of reducing the exposure of workers when handling operations at processing plants and power plants. For this reason, naturally, it is indispensable to have a structure adapted to automatic control of loading and unloading of the transport separator with respect to the nuclear fuel assembly. However, according to the prior art disclosed in Japanese Patent Laid-Open No. 8-201574 or Japanese Utility Model Laid-Open No. 6-40899, a metal separator has been proposed, but the positioning of the elastic contact bending lattice plate c is difficult to maintain with high accuracy. Is a hindrance to automation, and the elastic bent grid plate c is made of metal, and there is a concern that the fuel rod may hit or be scratched during automatic control. There is.
[0010]
[Problems to be solved by the invention]
  The present invention is in view of the characteristics of the MOX nuclear fuel assembly as described above.ThisBased on the configuration of the separator for transportation used in the conventional uranium nuclear fuel assemblies, this is to be further improved. It is made of a pair of metal bent in a U-shape that constitutes the separator body. The side frame plate is fitted around the outer periphery of the nuclear fuel assembly. At this time, the metal back plate separately fixed to the inner surface of the long side plate portion of the metal side frame plate has a metal protrusion and an elastic member. A plurality of metal bent lattice plates are provided so as to project orthogonally to each other. Thus, in the present invention, since all the metal material is used, the MOX nuclear fuel assembly can be used without fear of melting, and separately from the metal side frame plate, the metal protrusion or elastic contact with the metal back plate can be used. As well as making it possible to mount metal bent grid plates for use, it is also possible to easily change the design, etc., and to easily divert various parts that are changed by the design. The first purpose is to improve the work efficiency in production.
[0011]
  furtherThe present inventionIn this case, the metal protrusion is in the fuel rod group in the nuclear fuel assembly when in use and is not only circumscribed by the third and fourth outermost row fuel rods, but also in the gap between the fuel rod groups. In the metal bent lattice plate for elastic contact to be inserted in the elastic contact state, the outermost two are arranged on the outermost side, and the first and second outermost peripheries of the short side plate portion and the fuel rod group It should be held in elastic contact with the row fuel rods. By doing so, the transportation separator is mounted in a pressure contact state with the fuel rod group, so that the fuel rod group is surely formed of a metal material instead of a flexible synthetic resin material. Even so, it is possible to effectively prevent fretting between the fuel rod and the metal first and second metal bent lattice plates for elastic contact, so that the spacer spring receives an appropriate load, The purpose is to effectively suppress problems such as plastic deformation.
[0012]
  Furthermore, the present inventionIn that case,singleRather than projecting a metal bent grid plate for elastic contact to the metal back plate by welding means, etc., it is fitted into the inner sandwiching slit formed between the metal projections and held in an orthogonal state. Like to do. Thus, the elastic metal bent lattice plate can be erected without effort while maintaining a high-precision right angle to the metal back plate, and the elastic metal bent lattice plate. The purpose of this embodiment is to make it possible to set the separation length of the fuel rod to be uniform and to have an accurate dimension, and to ensure the uniformity of the holding state of the fuel rod with high accuracy. It is.
[0013]
  Furthermore, the present inventionIn that case,the aboveInA metal backboardEtRather than simply erecting a metal bent lattice plate for elastic contact by welding means, etc., cut out the required part of the metal back plate.Wake upIn this way, the bent upright portions are folded up as many as required, and the bent upright portions are pressed against the base portion of the metal bending lattice plate for elastic contact and fixed by welding, thus adding other members. Without having to do so, it is possible to ensure the standing angle of the metal bent lattice plate for elastic contact accurately and firmly so that it can be correctly inserted into the gap between the fuel rods without any trouble by means of automatic control. Is its purpose.
[0014]
  Furthermore, the present inventionIn that case,the aboveInIn the above, various embodiments of the outer shape of the metal protrusion provided on the metal back plate and the arrangement position are illustrated. Even if the outer shape is a rectangular shape or a bowl shape, Select the width direction edge of the back plate or the width direction center.AlsoIt clearly states that each objective can be achieved.
[0015]
  Furthermore, the present inventionIs,A tapered surface is formed on one or both sides of the tip of the elastic metal bent lattice plate, and the metal side frame plate is automatically controlled with respect to the nuclear fuel assembly. When trying to insert and set by this means, the tip of the elastic metal bent lattice plate can be easily introduced into the gap between the fuel rods without any trouble, and the cladding tube of the fuel rod is unintentionally scratched. Therefore, the purpose is to increase the effect of reducing the exposure to the worker by enabling the automatic control to be performed.
[0016]
  Furthermore, the present inventionIs,By adjusting the protrusion length of the metal protrusion described above and the bending width length of the elastic metal bent lattice plate which is the outermost arrangement, the different types of nuclear fuel assemblies having large and small outer peripheral dimensions The separator main body is covered with the body and surrounded by the metal side frame plate so that the outer dimensions thereof are substantially the same. Thus, in the present invention, both the separator body mounted on the nuclear fuel assembly having a large outer diameter and the separator body mounted on the nuclear fuel assembly having a small outer diameter are all provided with the outer diameter of the transport separator. It is possible to make the same adjustment, and as a result, it is sufficient to prepare only one type of fuel holder with a concise structure without adjusting the dimensions of the fuel holder used for transportation as described above. That is the purpose.
[0017]
[Means for Solving the Problems]
  In order to achieve the above object, the present invention provides the following: (01) ~ (04) The problem-solving means is characterized.
(01) The separator for transporting nuclear fuel assemblies according to the present invention is provided on a pair of metal side frame plates for constituting a separator body and inner surfaces of the pair of metal side frame plates as constituent elements of the transport separator. Metal back plate, a plurality of metal protrusions provided on the inner surface of each metal back plate, and a plurality of elastic metal plates provided on the inner surface of each metal back plate, respectively. And a long side plate portion in which the pair of metal side frame plates of the above are connected in an orthogonal manner between the pair of short side plate portions and the short side plate portions. And a metal back plate of the above is fixed to the inner surface of each long side plate portion of the pair of metal side frame plates, and a plurality of The metal protrusions are provided on the metal back plates. And a plurality of inner clamping slits are formed between the metal protrusions and are equally spaced, and a plurality of the above-mentioned elastic metal bendings are provided in the plurality of inner clamping slits. A plurality of metal protrusions and a plurality of elastic metal bent lattice plates protrude alternately and orthogonally from the respective metal back plates, and a lattice plate is fitted, and transportation The nuclear fuel assembly to which the separator is mounted includes a group of fuel rods in which fuel rods are arranged in a lattice matrix with a predetermined pitch and are vertically separated from each other, and a square outer periphery, and the square The outer periphery of the shape has a first outer side, a second outer side, a third outer side, and a fourth outer side, and the transportation separator component and the original side. In a relative relationship with the child fuel assembly, a pair of metal side frame plates are fitted and fitted around the first outer side and the second outer side of the outer periphery and are fitted around the outer periphery of the nuclear fuel assembly. And each of the metal protrusions of the metal back plate has a third outermost row of fuel rods in the fuel rod group near the third outer side or the fourth outer side of the outer periphery. The outermost row fuel rods are circumscribed, and a plurality of the metal back plates arranged on the inner side of each of the metal bent lattice plates for elastic contact are arranged in the fuel rod group. Inserted in the gaps between the 3 outermost peripheral fuel rods and the fourth outermost peripheral fuel rod and held in an elastic contact state with the fuel rod group, and in the elastic bent metal bent lattice plate The first outermost circumference in the fuel rod group in which the two arranged on the outermost side are close to the first outer side opposite to the outer periphery and the second outer side opposite side. Characterized in that it is intended to be held in elastic contact state between the short side plate of the fuel rod, the second outermost row fuel rods and the metal side frame plate.
(02) The separator for transporting nuclear fuel assemblies according to the present invention is also the above-mentioned (1) Gold listed inGenuine backboardPart ofTheFormed by cutting upBending standButMetal bent lattice plate for elastic contactAssigned to thisBending upright and elastic metal bent lattice plateButweldingsoFixationIt is characterized by being.
(03) The separator for transporting nuclear fuel assemblies according to the present invention further includes the above-mentioned (1) Or (2) Gold listed inFrom the genus backboardA plurality of protrudingMetal protrusionButPerpendicular to the short side plate of the metal side frameDoIn the directionAlongOne or more rows apartAndThatMetal protrusionAlignment position is the width direction edge side or width direction center of the metal back plateInYes, thatMetal protrusionThe outer shape is rectangularOrFormed into a bowlIt is characterized by being.
(04) The separator for transporting nuclear fuel assemblies according to the present invention further includes the above-mentioned (1) ~ (3) EitherIn the described one, at the tip of the metal bent lattice plate for elastic contact,On one or both sidesTaperforTaper surfaceButFormationIt is characterized by being.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of a separator for transporting nuclear fuel assemblies according to the present invention will be described with reference to the accompanying drawings.
[0019]
  As is apparent with reference to FIGS. 1 and 2, the separator body 1 isIt is comprised by a pair of metal side frame boards 1a and 1b bent in the U shape. Square shape as knownofThe nuclear fuel assembly 10 includes a firstOutside opposite side 10a, Second outer side 10b, and thirdOutside opposite side 10cAn outer periphery 10A composed of the fourth outer opposite side 10d is formed. The pair of metal side frame plates 1a and 1b in the separator main body 1 are fitted and sandwiched between the first and second outer opposite sides 10a and 10b with respect to the outer periphery 10A, thereby the first and second outer opposite sides. 10a, 10b and the third and fourth outer opposite sides 10c, 10d are configured to be fitted over the outer periphery 10A. Such a configuration is substantially the same as that of the conventional transport separator except that the material is not made of synthetic resin.
[0020]
  Of this exampleIn the nuclear fuel assembly 10,10E is a fuel rod group composed of a plurality of vertically mounted fuel rods 10e.Indicate10f is a water rod vertically mounted in the centerIndicate.
[0021]
  Each U-shape aboveMetal side frame plates 1a and 1bAnd eachRespective inner surfaces of the long side plate portions 1e and 1f arranged so as to be orthogonal to the pair of short side plate portions 1c and 1d.And this isAnother bodyofMetal back plate 1g, 1h is welded, screwing means, etc.soFixedIs done. ThisFrom the metal back plates 1g and 1h, there are a plurality of metal projections 1i and 1j and elastic metal bent lattice plates 1k and 1m each in a timely manner.IndividualAs shown in FIG. 1A, the metal protrusions 1i and 1j on the metal side frame plates 1a and 1b are located on the nuclear fuel assembly 10 at a predetermined pitch. Of the group of fuel rods 10E spaced vertically in a grid-like matrix arrangement, the third and fourth outermost circumferential row fuel rods (eight in the illustrated example) 10e3 near the third and fourth outer opposite sides 10c and 10d, 10e4 is in a circumscribed state.
[0022]
  On this occasion,Out of metal bent lattice plate 1k, 1m for elastic contactofA plurality (six in the illustrated example) of the inner arrangement are inserted from the gaps of the third and fourth outermost circumferential fuel rods 10e3 and 10e4 to be held in elastic contact with the fuel rod group 10E. IsRuAre two of the metal bent lattice plates 1k, 1m for elastic contact and arranged at the outermost side.IsUnlike the conventional example, the short side plate portions 1c and 1d in the metal side frame plates 1a and 1b, and the first and second outermost circumferential rows near the first and second outer opposite sides 10a and 10b in the fuel rod group 10E. The fuel rods 10e1 and 10e2 are held in an elastic contact state.
[0023]
  the aboveMetal bent lattice plate 1k, 1m for elastic contactabout,FIG. 1 (B)ThenA state where only one elastic metal bent lattice plate 1k is erected is disclosed. As a result, the attached stateButEasy to understandBecomeHave.FIG. 2 (A)ThenA case where all nine elastic metal bent lattice plates 1k are in a forested state is shown in FIG. 2 (B).In the side schematic diagram ofA state in which the fuel rod 10e is sandwiched and held by a pair of metal bent lattice plates 1k for elastic contactButIndicationHas been.ThereforeSuch an inventionWhen using the separator for transporting the nuclear fuel assembly, it is made of a metal material, so that it can be used without any concern for the MOX nuclear fuel assembly. Further, the metal back plates 1g and 1h, which are separately formed, are fixed on the inner surfaces of the long side plate portions 1e and 1f of the metal side frame plates 1a and 1b, so that the manufacture is easy. Moreover, the metal protrusions 1i, 1j and the third and fourth outermost circumferential fuel rods 10e3, 10e4 are in contact with each other during use, and the first and second outermost circumferential fuel rods 10e1, 10e2 and the short side plate portions 1c, 1d In the meantime, the elastic bent metal plates 1k and 1m are sandwiched between the elastic rods in an elastic state, so that vibration during transportation of the fuel rod group 10E can be effectively suppressed, and the fuel rod 10e Fretting for the cladding tube and plastic deformation of the spacer spring can be effectively prevented.
[0024]
  Separator for transporting nuclear fuel assemblies of the present inventionThe abovethingIn some configurationsThe embodiment is as follows. Ie aboveAmong the metal bent lattice plates 1k and 1m for elastic contact, those arranged on the inner side are orthogonal to the metal back plates 1g and 1h as shown in FIGS. 1 (B) and 2 (A). When standing, the base portion is fitted into the inner pinching slits 1n and 1p formed at equal intervals between the metal protrusions 1i and 1j. As for the remaining bent metal plates 1k, 1m for elastic contact (those arranged on the outermost side), as shown in FIG. 2 (A), the metal projections 1i, 1j on the outermost side and a pair of short side plates The base portion is fitted to the outer sandwiching slits 1q and 1r formed to be separated from the portions 1c and 1d, and the base portion is attached to the short side plate portions 1c and 1d of the metal side frame plates 1a and 1b. Arbitrary means such as fixing can be adopted.like thisIntroducing the embodimentIfThe first and second inner pinching slits 1n and 1p are provided accurately.By puttingEven if the metal bending lattice plates 1k and 1m for elastic contact are simply inserted into this, the mutual spacing and mutual positioning with respect to the metal side frame plates 1a and 1b can be obtained. Further, if the depths of the inner sandwiching slits 1n and 1p are appropriately selected, the cantilever length of the elastic metal bent lattice plate 1k and 1m can be increased, and the uprightness is ensured. It becomes easy. In addition, by appropriately adjusting the pitch of each of the sandwiching slits 1n and 1p, when manufacturing a transportation separator that is inserted and fitted into a nuclear fuel assembly having a different pitch of the fuel rod 10e in the fuel rod group 10E. Even if it exists, other parts can be diverted only by changing the design of the metal back plates 1g and 1h.
[0025]
  With reference to FIG. 5, the separator for transporting nuclear fuel assemblies of the present invention further comprisesMetal side frame plates 1a, 1bInFixedWasSeparation location 1s so that it becomes a rectangular or other shape discontinuously on the metal back plate 1g, 1hButProvide an appropriate numberAnd1s from the non-separation line 1tButWrappingAnd formed by thisBending upright part 1uButOrthogonal to metal back plate 1g, 1hTo stand up to do. thisBending upright part 1uButThe elastic bent metal bent lattice plates 1k, 1m are welded and fixed in contact with each other, preferably from both sides. In such an embodiment, the elastic metal bent lattice plates 1k, 1m are simplified and firmly fixed to the metal back plates 1g, 1h of the metal side frame plates 1a, 1b. Therefore, the role as a separator can be sufficiently exhibited, and the durability can be promoted.
[0026]
  In the aboveArrangement position and form of metal protrusions 1i, 1jIs as follows. First, metal protrusions 1i, 1jabout,this1B and 4A, the metal back plates 1g and 1h of the metal side frame plates 1a and 1b, respectively.Multiple things protruding fromIs the metal side frame 1a, 1bofIn the direction orthogonal to the short side plate portions 1c and 1dAlongOne or more rows are provided apart. In this caseMetal protrusions 1i, 1jAre arranged at the edge in the width direction of the metal back plates 1g and 1h or at the center in the width direction as shown in FIG. Two rows of metal protrusions 1i, 1j on the edge in the width directionButSpacing projectingAndAnd,Metal bent lattice plates 1k, 1m for elastic contact are sandwiched between slits 1n, 1p for inner clampingIsIf this is the case, it can be erected with a more desirable strength.On the other hand,Various shapes can be selected for the shape of the metal protrusions 1i and 1j.. that isAs shown in FIGS. 1 (B) and 2 (B), the outer shape can be a rectangular body, or as shown in FIG. 4 (A), the outer shape can be a curved metal plate. In the case of cutting 1n and 1p, it is desirable that the elastic metal bent lattice plates 1k and 1m be clamped sufficiently firmly.
[0027]
  Referring to FIG.Metal bent lattice plates 1k for elastic contact projecting orthogonally from the metal back plates 1g and 1h of the metal side frame plates 1a and 1b, the tip portions 1v of the metal side frame plates 1a and 1b.InTapered taper surface 1wButFormationIs done. Specifically, the tip 1vOn one or both sides in the thickness directionIt is formed. If you do this,When the transport separator is inserted into the nuclear fuel assembly by automatic control, it is easy to reliably avoid the impingement of the fuel rod group 10E against the cladding tube, and the worker is exposed to exposure. It is possible to release from dangerous work.
[0028]
  The separator for transporting nuclear fuel assemblies of the present invention according to another embodiment is obtained by adding the following configuration to the above configuration. This is shown in FIGS. 3A and 3B.By adjusting the small protrusion length p1 and the large protrusion length p2 of the metal protrusions 1i and 1j and the bending width lengths w1 and w2 of the metal bent lattice plates 1k and 1m for outermost contact, respectively, Increase or decrease the size of the outer periphery 10AHaveThe metal side frame plates 1a and 1bd are fitted over the large-sized nuclear fuel assemblies 10L and the small-sized nuclear fuel assemblies 10S.AtFormationWhere to doThe outer shapes of the separator bodies 1 and 1 are made to have substantially the same dimensions.. To elaborate further on this,3 (A) large-sized nuclear fuel assembly 10L has a large outer dimension L1 on one side thereof, and L1 is large. Therefore, the small protrusion length p1 of the metal protrusions 1i and 1j and the metal bending for elastic contact The small bending width length w1 of the lattice plates 1k and 1m is adjusted to be relatively small. On the other handFigureThe small-sized nuclear fuel assembly 10S of 3 (B) has a small-diameter dimension L2 that is one side thereof.ButSince it is smaller than L1, the large protrusion length p2 of the metal protrusions 1i, 1j, the large bending width length w2 of the metal bent lattice plates 1k, 1m for elastic contact, andTheBy adjusting relatively large,The outer dimensions of any of the separator bodies 1 and 1 are the same..In other words, L1 + 2p1 = L1 + 2w1 = L and L2 + 2p2 = L2 + 2w2 = L.TheAt this time, L1 <L2, p1 <p2, and w1 <w2.It is. In such an embodiment,The dimensions of the separator body 1 constituted by the metal side frame plates 1a and 1b are unified. The heights of the metal protrusions 1i and 1j are only two types, that is, a small protrusion length p1 and a large protrusion length p2. If the outermost elastic metal bent lattice plates 1k and 1m are also prepared with two types of separators of small bending width length w1 and large bending width length w2, respectively, FIG.As explained inWhen the nuclear fuel assembly 10 is accommodated in the fuel holder B,Fuel holder B sideInIt is possible to safely package nuclear fuel assemblies having different outer dimensions without disposing the silicon rubber plate g and adjusting the dimensions. In FIG. 7, the spacer 11 of the nuclear fuel assembly 10 is disposed below the separator body 1 as is known.
[0029]
【The invention's effect】
  The separator for transporting nuclear fuel assemblies according to the present invention is as follows. (11) ~ (16) It has the following effects.
(11) Since all metal materials are used and synthetic resin materials are not adopted, they can be used without being dissolved even when used for MOX nuclear fuel assemblies, and are formed separately on the long side plate of the metal side frame plate. The metal back plate is fixed, and metal protrusions or elastic metal bent grid plates are attached to this, so that the design can be easily changed as well as the work. Top efficiencyButImprovementAndRepair work is also facilitated.
(12) A metal protrusion is brought into contact with the fuel rods on opposite sides on the outer periphery of the fuel rod group.AndWith respect to the fuel rods arranged on the other two sides, the metal rod lattice plate for elastic contact which is located on the outermost side and is received by the short side plate portion is configured to be elastically contacted. The group is made of metal, and the fear of fretting is corrected by the elastic metal bent lattice plate.,It is possible to improve the conventional defects such as plastic deformation caused by vibration of the fuel rod group in the spacer spring.
(13) Since the metal bent lattice plate for elastic contact is made to stand upright by being clamped in the inner clamping slit between the metal projections provided on the metal back plate, the uprightness can be easily and reliably It is possible to guarantee the fuel rods uniformly and with high accuracy by simple work.The intendedAchieve your goals more reliablyDobe able to.
(14) Since the bent upright portion is formed by the metal back plate, and this is abutted against the base side surface of the metal bent grid plate for elastic contact, it is fixed by welding. Even in the case of control, it is possible to promote the above-described effect that the transport separator can be safely mounted by inserting the fuel rod into the gap between the fuel rods without any trouble.
(15) The outer shape of the metal protrusion is a square or bowl, and,By selecting the row position on the edge side of the metal back plate in the width direction or on the center in the width direction, it can be matched to various design purposes.IntendedThe objective can be achieved more reliably.
(16) At the tip of the metal bent lattice plate for elastic contact,On one or both sidesSince the taper surface for taper is formed, it is possible to prevent the fuel rod from being accidentally scratched when loading the separator for transportation by automatic control, and to perform the loading quickly. , It will also help to reduce exposure,aboveThe effect can be guaranteed.
[Brief description of the drawings]
[Figure 1]In the present inventionSuch a separator for transporting nuclear fuel assemblies is shown.With(A)ThatA cross-sectional top view of the nuclear fuel assembly inserted and covered,(B) is the perspective view which left and showed only one metal bending | flexion metal bent grid board provided in the one metal side frame board which is the one part.
[Figure 2] (A)In the separator for transporting nuclear fuel assemblies of the present inventionThe perspective view which shows the other metal side frame board, (B) is a partial front view which shows a pair of metal bending lattice board for elastic contact which clamps and holds one fuel rod.
[Fig. 3]According to the present inventionNuclear fuel assembly separatorabout,(A) is a cross-sectional top view showing a type for inserting and fitting into a large-sized nuclear fuel assembly, and (B) is a cross-sectional top view showing a type for inserting and fitting into a small-sized nuclear fuel assembly.
[Fig. 4]In the present inventionOne metal side frameabout,(A) shows a case where a metal protrusion having a different shape from that in FIG. 1 (B) is adopted.An explanatory diagram schematically showing(B) is similar to FIG. 1 (B) in the case where metal protrusions are provided at different arrangement positionsAbbreviatedIt is explanatory drawing.
[Figure 5]In the present inventionMetal side frame plateabout,A state in which the metal projection is reinforced by bending uprightsAbbreviatedIt is a perspective view.
[Fig. 6]In the present inventionIt is the perspective view which notched a part of metal bending lattice board for elastic contact.
FIG. 7A is a nuclear fuel assembly.The present inventionCovered with a separator for transportationTheThis shows the state where it is further stored in the fuel holder.YouPerspective view, (B)MeijiIt is a cross-sectional explanatory drawing which shows the state which accommodated the sending separator in the peculiar fuel holder.
FIG. 8A is a conventional separator for transporting nuclear fuel assemblies.ofPlan view showing one side frame,(B) is a lower side view thereof.
[Explanation of symbols]
    1 Separator body
    1a Metal side frame plate
    1b Metal side frame
    1c Short side plate
    1d Short side plate
    1e Long side plate
    1f Long side plate
    1g metal backboard
    1h Metal back plate
    1i Metal protrusion
    1j Metal protrusion
    1k metal bent lattice plate for elastic contact
    1m metal bent lattice plate for elastic contact
    1n Slit wearing slit
    1p slit for wearing inside
    1q Outer pinch slit
    1r outer slit wearing slit
    1t non-separation line
    1u bent upright
    1v Tip location
    1w taper surface
  10 Nuclear fuel assemblies
  10A Outer periphery
  10E Fuel rod group
  10a First outside opposite side
  10b Second outside opposite side
  10c Third outside opposite side
  10d 4th outside opposite side
  10e Fuel rod
  10e1 first outermost row fuel rod
  10e2 Second outermost row fuel rod
  10e3 Third outermost row fuel rod
  10e4 Fourth outermost row fuel rod
    L Same dimension
    w1 Small bending width
    w2 Large bending width
    p1 Small protrusion length
    p2 Large protrusion length

Claims (4)

As a constituent element of the separator for transportation, a pair of metal side frame plates for constituting the separator main body, a metal back plate provided on the inner surface of the pair of metal side frame plates, and each metal back plate A plurality of metal protrusions respectively provided on the inner surface of the metal back plate, and a plurality of elastic metal bent lattice plates respectively provided on the inner surface of each metal back plate, and A pair of metal side frame plates are formed of a U-shape having a pair of short side plate portions facing each other and a long side plate portion connected orthogonally between the two short side plate portions, and The metal back plates are fixed to the inner surfaces of the long side plate portions of the pair of metal side frame plates, and a plurality of the metal protrusions are the metal back plates. And a plurality of inner pinching slits A plurality of metal bent grid plates for elastic contact are fitted into a plurality of inner sandwiching slits formed between metal protrusions, and the plurality of metals Protruding portions and a plurality of elastic metal bent lattice plates protrude alternately and orthogonally from the respective metal back plates, and an atomic fuel assembly that receives the mounting of a transport separator is a fuel. A fuel rod group in which rods are arranged in a grid pattern with a predetermined pitch and arranged vertically, and a square outer periphery, and the square outer periphery is a first outer opposite side and a second outer periphery. In the relative relationship between the opposite side, the third outer side opposite side, and the fourth outer side opposite side, and the relative relationship between the transport separator component and the nuclear fuel assembly, a pair of metal side frame plates has the outer periphery. Between the first outer side and the second outer side And the metal protrusions of the metal back plate are close to the third outer side and the fourth outer side of the outer periphery. It is circumscribed by the third outermost row fuel rod and the fourth outermost row fuel rod in the fuel rod group, and inside the elastic metal bent lattice plate of the metal back plate. A plurality of arranged rods are inserted from the gaps of the third outermost row fuel rod and the fourth outermost row fuel rod in the fuel rod group and held in a resilient contact state with the fuel rod group. The first outermost circumferential row in the fuel rod group in which the two outermost arranged metal bent grid plates for elastic contact are located near the first outer side or the second outer side of the outer periphery. It is held in a resilient contact state between the fuel rod / second outermost row fuel rod and the short side plate portion of the metal side frame plate. A separator for transporting nuclear fuel assemblies. Bent standing portions are formed by cutting and raising a part of the metallic steel back plate is Ategawa the metal bending grid plate for elastic contact, at the bent upright portion and the elastic contacting a metal bending grid plate and is welded The separator for transporting a nuclear fuel assembly according to claim 1, which is fixed. Along the direction in which a plurality of metallic protrusions projecting from the metallic steel back plate is orthogonal to the short side plate portion of the metal side frame plate is provided spaced apart above one row, column of the metallic projection 3. The nuclear fuel according to claim 1, wherein the installation position is at the width direction end edge side or the width direction center of the metal back plate , and the outer shape of the metal protrusion is formed in a square shape or a bowl shape. Separator for aggregate transportation. The separator for transporting nuclear fuel assemblies according to any one of claims 1 to 3, wherein a taper surface for taper is formed on one side or both side surfaces of the tip portion of the metal bent lattice plate for elastic contact.

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