Storage device designed for improved mechanical strength, for temporary storage and / or transportation of nuclear fuel elements

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of transport and / or storage of nuclear fuel assemblies, preferably spent assemblies within which the fuel has been irradiated. STATE OF PRIOR ART

[0002] Such a device, also called a storage “basket” or “rack”, comprises a plurality of adjacent housings each capable of receiving a nuclear fuel assembly.

[0003] This storage device is intended to be housed in a cavity of a package. The package, the basket and the fuel assemblies which are placed in the housings of the basket, form a package.

[0004] The basket is designed to be able to simultaneously fulfill three essential functions, which will be briefly explained below.

[0005] First of all, it is the heat transfer function of the heat released by the fuel assemblies. Usually, aluminum or one of its alloys is used, due to its good thermal conduction properties.

[0006] The second function concerns neutron absorption, and the concern to maintain the subcriticality of the package. This is achieved by using, within the basket, neutron-absorbing materials called neutron-absorbing materials, such as boron.

[0007] Finally, the third essential function relates to the mechanical resistance of the device. It is noted that the overall mechanical resistance of the device must be compatible with the regulatory safety requirements for the transport / storage of nuclear materials, particularly with regard to the so-called "free fall" tests of the package, from different directions.

[0008] Several ways of forming the basket are known from the prior art. One of these consists of providing transverse structures, such as wafers, spaced from each other by spacers, in the longitudinal direction of the basket. In addition, sleeves, generally of square section and oriented longitudinally, pass through the transverse structures, and each form a housing for receiving a nuclear fuel assembly.

[0009] Transverse structures, provided with through openings for the passage of the sleeves, are usually made of a single piece. In the case of a regulatory lateral free fall test with a so-called oblique orientation (for example at 45°), the transverse structures oriented parallel to the direction of fall undergo an impact at a wedge-shaped peripheral part, for example forming a V with an angle of 90°, the V corresponding to the peripheral corners of the through openings. This drop orientation of the package leads to strong stress on the V-shaped peripheral part, with a significant risk of deformation leading to the unwanted opening of this V. To avoid or limit this deformation, which is detrimental to the certification of the package, the transverse structures can be reinforced by being oversized, and / or by integrating reinforcing elements.

[0010] In any case, this approach to reducing the risk of deformation leads to an increase in the cost and mass of transverse structures, which is not desirable.

[0011] Document WO 2021 / 058887 A1 discloses a storage device for the transport and / or storage of nuclear fuel assemblies according to the preamble of claim 1. STATEMENT OF THE INVENTION

[0012] The invention therefore aims to remedy the drawbacks mentioned above, relating to the achievements of the prior art.

[0013] To this end, the invention relates to a storage device for the transport and / or storage of nuclear fuel assemblies, the storage device being intended to be housed in the cavity of a package for the transport and / or storage of nuclear fuel assemblies, and comprising adjacent housings, each intended to receive a nuclear fuel assembly.

[0014] In addition, the storage device comprises a plurality of transverse structures spaced from each other in a longitudinal direction of the storage device using spacing means such as for example spacers placed between the transverse structures, each of these transverse structures being arranged in a transverse plane of the storage device and each comprising several through openings for the passage of the nuclear fuel assemblies.

[0015] According to the invention, at least one of the transverse structures, and preferably several or even all of them, comprises a first part and a second part fixed to each other by a connecting device, the connecting device comprising: a male coupling member carried by the first part, the male member taking the form of a projection; a female coupling member provided on the second part, the female member taking the form of a groove housing the male member and forming with it a sliding connection whose sliding direction is parallel or inscribed in the transverse plane in which the transverse structure concerned is located.

[0016] The invention therefore provides for producing one or more of the transverse structures no longer in a single piece, but with at least two separate parts assembled to each other in the manner set out above. Thanks to the particular orientation of the sliding connection, in or parallel to the plane of the transverse structure which generally has a relatively small thickness, the length of cooperation between the male and female coupling members which form this connection can advantageously be high. This advantageously results in a reinforcement of the mechanical strength of the transverse structure in the event of the package falling, without impacting the mass of the transverse structure.

[0017] The invention further provides at least one of the following optional features, taken alone or in combination.

[0018] Preferably, the groove forming the female member has, at one of its two longitudinal ends opposite in the sliding direction, an axial slide stop cooperating with one of the two longitudinal ends opposite of the projection forming the male member.

[0019] Thus, in the event of the package falling, the mechanical strength of the transverse structure is further reinforced by the support between the axial stop of the slide and the associated longitudinal end of the male member. This support can be obtained directly by construction, or by consumption of a small clearance during the fall.

[0020] Preferably, the axial slide stop and the associated longitudinal end of the projection have a complementary shape ensuring the maintenance of the longitudinal end of the projection in the groove, in a stacking direction of the male and female coupling members, the stacking direction being orthogonal to the slide direction as well as to an opening plane of the groove. This arrangement leads to a bilateral design of the slide connection.

[0021] In the event of the package falling, the mechanical strength of the transverse structure is further reinforced by holding the longitudinal end of the male member in the groove. The form cooperation can be achieved directly by construction, or by consuming a small amount of play during the fall.

[0022] According to a first possibility, the sliding connection is of unilateral design in a stacking direction of the male and female coupling members, the latter preferably having parallelepiped shapes.

[0023] According to a second preferred possibility, the sliding connection is of bilateral design in a stacking direction of the male and female coupling members, the projection and the groove having a complementary shape preventing the extraction of the projection outside the groove via the opening of the latter, according to the stacking direction of the male and female members.

[0024] Thanks to this bilateral design in the stacking direction of the male and female members, in the event of the packaging falling, the mechanical strength of the transverse structure is further reinforced by maintaining the projection in the groove.

[0025] Preferably, the projection has two opposite lateral flanks having a complementary shape with two opposite lateral flanks of the groove with which they cooperate respectively, so as to prevent the extraction of the projection outside the groove via the opening of the latter, in the direction of stacking of the male and female members.

[0026] Preferably, the projection has a section, in a plane orthogonal to the slide direction, in the shape of a dovetail, a T, or all or part of a disc.

[0027] Preferably, said longitudinal end of the projection, as well as its two opposite lateral flanks, have a continuous profile along a U-shaped contour of the projection.

[0028] For example, when a dovetail shape is chosen, each of the two lateral flanks is beveled so as to reveal the acute angle required to obtain such a dovetail shape, and this same acute angle is made at the longitudinal end of the projection in order to ensure continuity with each of the two lateral flanks of the projection, of the same shape.

[0029] This advantageously results in ease of manufacturing for this sliding connection configuration with reinforced retention of the projection in the groove.

[0030] Preferably, the storage device comprises a sliding connection locking member, holding the male member relative to the female member in the sliding direction, the sliding connection locking member preferably being a screw passing through the male and female members. Preferably, the screw(s) only allow the two parts to be held in position relative to each other, but they are not or only very little stressed during the impact in the event of a fall, since it is primarily the male and female members of the sliding connection which take up the impact forces.

[0031] Preferably, the first and second parts are two peripheral parts of the transverse structure, and preferably partially delimiting at least one of the through openings of this transverse structure.

[0032] Preferably, the first or second part has a general shape of a straight beam, the longitudinal central axis of which is parallel or coincident with the slide direction.

[0033] Preferably, said transverse structure comprises a third part arranged so that the second part is located between the first and third parts which it connects using another connecting device, this other connecting device comprising: a male coupling member carried by the third part, the male member taking the form of a projection; a female coupling member provided on the second part, the female member taking the form of a groove housing the male member and forming with it a sliding connection whose sliding direction is parallel or inscribed in the transverse plane in which the transverse structure concerned is located.

[0034] Preferably, in said other connecting device, the groove forming the female member has, at one of its two opposite longitudinal ends along the sliding direction, an axial slide stop cooperating with one of the two opposite longitudinal ends of the projection forming the male member. In addition, on the second part, the two axial slide stops, respectively provided on the two sliding connections, are oriented so as to prevent the movement of the first part relative to the second part in the direction of the third part, and so as to prevent the movement of the third part relative to the second part in the direction of the first part.

[0035] Thus, in the event of a fall oriented parallel to the direction in which the three parts follow one another, the two axial slide stops lead to the second part being compressed between the first and third parts, to obtain reinforced mechanical strength of the transverse structure, and thus a better guarantee of maintaining its parts in relation to each other.

[0036] Preferably, the transverse structure has a ratio between its thickness and its maximum width in the transverse plane in which it is located, less than 0.1.

[0037] The invention also relates to a package, comprising a packaging for the storage and / or transport of nuclear fuel assemblies, as well as a storage device as described above, housed in a cavity of the packaging, as well as nuclear fuel assemblies arranged in the storage device.

[0038] Other advantages and characteristics of the invention will appear in the detailed non-limiting description below. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] This description will be made with regard to the attached drawings, among which; [ Fig. 1 ] represents a schematic sectional view of a package according to the invention, comprising in particular a storage device for the storage and / or transport of nuclear fuel assemblies; [ Fig. 2 ] represents a partial perspective view of the storage device, according to a preferred embodiment of the present invention; [ Fig. 2A ] represents a partial perspective view of the storage device shown in the preceding figure, and on which the upper transverse structure has been removed; [ Fig. 3 ] is a top view of a cross-sectional structure of the storage device shown in the figures 2 And 2A ; [ Fig. 4] is an exploded perspective view of the transverse structure of the storage device shown in the preceding figure; [ Fig. 5 ] is a perspective view of a portion of a first piece of the transverse structure shown in the preceding figure; [ Fig. 6 ] is a perspective view of a portion of a second piece of the transverse structure shown in the preceding figure; [ Fig. 7 ] represents a perspective view of a connecting device between the first and second parts, with the second part made of wireframe for greater clarity; [ Fig. 8 ] represents a perspective view of a connecting device between the first and second parts, with the first part made of wireframe for greater clarity; [ Fig. 9 ] represents a longitudinal sectional view of the connecting device shown in the figures 7 And 8 ; [ Fig. 10] represents a cross-sectional view of the connecting device shown in the figures 7 to 9 ; [ Fig. 11 ] represents a cross-sectional view similar to that of the figure 9 , with the connecting device being in the form of an alternative embodiment; and [ Fig. 12 ] represents a top view similar to that of the figure 3 , showing only part of the transverse structure of the storage device. DETAILED DISCLOSURE OF PREFERRED EMBODIMENTS

[0040] In reference to the figure 1, a package 100 is shown comprising a packaging 200 for the storage and / or transport of irradiated nuclear fuel assemblies 2. The packaging 200 has a body 202 formed by a lateral body 204, a bottom 206, and a removable cover 208. The bottom 206 and the cover 208 are spaced from each other along the longitudinal central axis 3 of the packaging, around which the lateral body 204 extends. The packaging 200 defines inside its body a cavity 210, in which is housed a storage device 1, which will be called a “basket” in the remainder of the description. The basket 1 thus completes the packaging 200 to form the package 100, the latter being loaded with nuclear fuel assemblies. Indeed, as will be detailed below, the basket 1 comprises a plurality of adjacent housings each intended to receive one of the nuclear fuel assemblies 2.When the basket 1 is housed in the cavity 210 of the package 200, and the nuclear fuel assemblies 2 are placed in the adjacent housings of the basket 1, the package 100 is said to be “loaded”.

[0041] For information purposes, it is noted that at the axial ends of the packaging, the latter may have shock-absorbing covers 212, respectively covering the lid 208 and the bottom 206 of the body 202 of this packaging.

[0042] The particularity of the invention lies in the design of the basket 1 for transporting and / or storing irradiated nuclear fuel assemblies, which will now be described with reference firstly to figures 2 And 2A .

[0043] The basket 1 comprises a plurality of adjacent housings 4, 4' arranged parallel to the axis 3, the latter also corresponding to the longitudinal central axis of the basket 1.

[0044] The number N of adjacent dwellings here is four, but this number could of course differ.

[0045] The two facing housings 4 are each capable of receiving at least one fuel assembly 2 of square section, and preferably only one. As a result, they each have an inner housing delimiting surface 10, of generally square or rectangular cross-section. By “inner housing delimiting surface 10” is meant the surface of the basket elements which is directly opposite the outer surface of the fuel assemblies 2.

[0046] The two facing housings 4' are also each capable of receiving at least one fuel assembly 2' of circular section, and preferably only one. As a result, they each have an inner housing delimiting surface 10', of generally circular cross-section. Here too, by "inner housing delimiting surface 10'" is meant the surface of the basket elements which is directly opposite the outer surface of the fuel assemblies 2'.

[0047] The housings 4, 4' are therefore provided so as to be juxtaposed with each other, here all at the periphery of the basket. Each housing 4, 4' is produced by a jacket 9, 9' parallel to the axis 3, and preferably extending over the entire height of the basket 1 in a longitudinal direction 20 of the latter, or substantially over this entire height. Each jacket 9, 9' is respectively of square / rectangular or circular section. For the jackets 9 of square or rectangular section, these can each be produced using several plates assembled together, for example four plates assembled by intersecting.The material used to manufacture the liners 9, 9' is chosen so as to contribute to the different functions, namely the mechanical function, the thermal function, and the neutron absorption function. For example, a material such as a metal alloy comprising boron or any other neutron-absorbing element, i.e. comprising neutron-absorbing elements, may be chosen. By "neutron-absorbing elements", we mean elements which have an effective cross-section greater than 100 barns for thermal neutrons. As indicative examples, these are aluminum alloys comprising boron.

[0048] To complete the design of the basket 1, the latter comprises a plurality of transverse structures 11, spaced from each other in the direction 20. The transverse structures 11 are planar or substantially planar structures, each arranged in a transverse plane P of the basket 1, that is to say orthogonally to the axis 3. The transverse structures 11 are preferably identical or substantially identical, and they each have a small thickness, preferably so that a ratio between its thickness “E”, and its maximum width “L” in the transverse plane P in which it is inscribed, is less than 0.1.

[0049] In the general shape of a disc or a pancake, each of these structures 11 has four through openings 13, 13' for receiving respectively the four sleeves 9, 9'. In other words, the same sleeve 9, 9' successively passes through an opening 13, 13' of each of the pancakes 11 of the basket 1. The same is true for the assemblies 2, 2', which successively pass through these openings 13, 13', while being housed inside the sleeves 9, 9'. The shape of the openings 13, 13' is also complementary to that of the sleeves which pass through them. Consequently, the through openings 13 have a general shape of square or rectangular section, while the through openings 13' have a general shape of circular section.

[0050] The wafers 11 are for example made of steel or a metal alloy, for example an aluminum alloy. But whatever the material chosen, it is preferably free of boron or any other neutron-absorbing element in the sense explained above.

[0051] The number of pancakes 11 is for example between five and twenty, even if a different number could be adopted, in particular depending on the height of basket 1, here of the order of 4 m.

[0052] These wafers 11 are spaced longitudinally from each other using spacing means, here spacers 16, several of which are arranged between each pair of directly consecutive wafers 11 in the stack in the direction 20. For example, three to six spacers 16 are provided at each spacing level between the wafers 11, the spacers of the same level preferably all having the same height in the direction 20. The spacers 16 are preferably made of steel, but other materials can be envisaged, without departing from the scope of the invention.

[0053] The structure of the basket 1 is completed by tie rods 17 which hold the pancakes 11 and the spacers 16 in compression against each other, in the direction 20. The mechanical maintenance of the stack is thus ensured by the tie rods 17 which pass through the pancakes 11, and possibly also the spacers 16, by providing a hollow design for the latter. The number of tie rods 17 can then be identical to that of the spacers 16 provided at each spacing stage of the pancakes, for example four spacers / tie rods in the embodiment shown in the figures 2 And 2A The tie rods 17, of known design, are preferably parallel to the axis 3, or substantially parallel to the latter.

[0054] One of the particularities of the invention lies in the design of the transverse pancakes 11, one of which will now be described with reference to figures 3 to 10 .

[0055] The pancake 11 is made using several pieces fixed to each other, all falling within the transverse plane P associated with this pancake. In the preferred embodiment shown, four peripheral pieces are provided, assembled end-to-end and therefore following one another in a circumferential direction 22 of the basket 1.

[0056] This firstly involves a first peripheral part 11a of generally trapezoidal shape, or in the form of a lunule, and through which one of the two openings 13' of circular section is made. A second peripheral part 11b is then provided in the general shape of a straight beam, or possibly a lunule, the curved part of which is not very accentuated. A third peripheral part 11c of generally trapezoidal shape is also provided, identical or substantially identical to the first part 11a, being arranged opposite and symmetrically to it. The third peripheral part 11c is crossed by the other of the two openings 13' of circular section. Finally, a fourth peripheral part 11d is provided in the general shape of a straight beam, or possibly a lunule, identical or substantially identical to the second part 11b, being arranged opposite and symmetrically to it.Finally, a fifth central piece 11e connects the first and third pieces 11a, 11c, being arranged between the second and fourth pieces 11b, 11d, parallel to them.

[0057] Parts 11a and 11c, with larger transverse extents, are those intended to cooperate with the tie rods and the spacers of the basket.

[0058] One of the openings 13 of square / rectangular section is delimited by a part of the first part 11a, by the second part 11b, by a part of the third part 11c, and by a face of the fifth part 11e. Similarly, the other opening 13 of square / rectangular section is delimited by another part of the first part 11a, by the fourth part 11d, by another part of the third part 11c, and by an opposite face of the fifth part 11e.

[0059] Subsequently, the fixing between the first and second parts 11a, 11b will be described, specific to the invention, and the principle of which is preferably applied in an identical or similar manner for the three other fixings between the peripheral parts 11a to 11d.

[0060] Still referring to the figures 3 to 10 , a rigid connecting device 24 is thus implemented between the first part 11a and the second part 11b.

[0061] The connecting device 24 firstly comprises a male coupling member 26 carried by the first part 11a, being here integral and preferably made in a single piece with this first part 11a. The male member 26 takes the form of a projection at one end of the first part 11a. The connecting device 24 also comprises a female coupling member 28 provided on the second part, this female member taking the form of a groove housing the male member 26 and forming with it a sliding connection whose sliding direction 30 is parallel or inscribed in the transverse plane P in which the transverse structure 11 is located. This sliding direction 30 is moreover coincident with or parallel to a longitudinal central axis 32 of the second part 11b, also inscribed in the plane P.

[0062] Thanks to the orientation of this sliding connection, in the plane P of the pancake 11 or parallel to this same plane, the cooperation between its male and female members 26, 28 can advantageously extend over an extended length which reinforces the mechanical resistance of the pancake 11, in the event of the package falling. In particular, it is provided that this cooperation length L1, referenced on the figure 8, or strictly greater than the thickness E of the parts 11a, 11b, corresponding to the thickness of the disc 11. Preferably, the connecting device 24 includes a locking member 34 of the slide connection, the objective of which is to maintain the male member 26 relative to the female member 28 in the slide direction 30. This locking member 34 thus prevents disengagement of the two members, in particular during assembly of the basket, but it is preferably mounted so as not to be stressed or stressed little in the event of a fall, the absorption of forces being carried out primarily using the members 26, 28. Preferably, the locking member 34 of the slide connection is a screw passing through the male and female members 26, 28, being preferably orthogonal to the slide direction 30, and parallel or inscribed in the plane P.

[0063] The groove 28 forming the female member has a first and a second longitudinal end 28a, 28b opposite in the direction of slide 30. The first end 28a, corresponding to the outermost end and the furthest from the axis 3 of the basket and the disc, is open for the introduction of the projection 26. Similarly, this projection 26 has a first and a second longitudinal end 26a, 26b opposite in the direction of slide 30. The introduction of this projection 26 into the groove 28 is provided by making the second end 26b penetrate into the groove before the first end 26a. On the other hand, to further reinforce the mechanical resistance of the slide connection in the event of a fall, the second end 28b of the groove 28 is closed by an axial slide stop 36 cooperating with the second end 26b of the projection 26.Contact is provided between the two, or a very small clearance according to the direction of slide 30, intended to be quickly consumed in the event of a fall to obtain support reinforcing the mechanical resistance of the disc 11.

[0064] The axial slide stop 36 and the associated longitudinal end 26b of the projection 26 have a complementary shape ensuring that this longitudinal end 26b is held in the groove 28, in a stacking direction of the male and female coupling members 26, 28. This stacking direction, referenced 38 on the figures 7 to 10, is orthogonal to the slide direction 30, and also orthogonal to an opening plane of the groove. The complementarity of shape ensuring the retention of the two elements 26b, 36 can be achieved by a simple notch at the end 26b, so as to cooperate with a notch of complementary shape in the axial slide stop 36. Here also, this retention improves the mechanical resistance of the disc in the event of a fall.

[0065] If the sliding connection can be of unilateral design in a stacking direction 38, for example with a projection 26 and a groove 28 of complementary parallelepiped shapes, this sliding connection is preferably of bilateral design in the stacking direction 38, always for the purpose of reinforcing the mechanical strength of the wafer 11. To do this, the projection 26 and the groove 28 have a complementary shape preventing the extraction of the projection outside the groove via the opening of the latter, in the stacking direction 38. This complementary shape is preferably produced at the level of the two opposite lateral flanks 42 of the groove 28, which cooperate respectively with two opposite lateral flanks 40 of the projection 26, so as to prevent the extraction of the projection 26.

[0066] Preferably, a notch is provided at each of the two opposite lateral flanks 40 of the projection 26, this notch being identical or similar to that made at the second end 26b of the projection 26. Thus, the projection 26 has a section, in a plane orthogonal to the slide direction 30 such that the cutting plane of the figure 9 , dovetail-shaped. Alternatively, other sectional shapes capable of providing retention are possible, such as the shape of a T, or all or part of a disc.

[0067] In this way, the second end 26b of the projection, as well as its two opposite lateral flanks 40, have a continuous profile along a U-shaped contour of the projection 26, as is best seen in the figures 5 , 7 And 8. For example, when a dovetail shape is retained as shown in these figures, each of the two lateral flanks 40 is beveled so as to reveal the acute angle required to obtain such a dovetail shape, and this same acute angle is made at the longitudinal end 26b of the projection in order to ensure continuity with each of the two lateral flanks 40, of the same shape. To allow this continuity, the end 26b may have connecting radii, or else be itself rounded as has been shown in the figures. Such an embodiment with a continuous shape, which is found on the U-shaped contour of the groove formed by the lateral flanks 42 and the stop 36, facilitates the manufacture of the two parts 11a, 11b.

[0068] It is noted that if the projection 26 has been shown as integrated into the first part 11a, and the groove 28 integrated into the second part 11b, a reverse design can be envisaged, without departing from the scope of the invention. Furthermore, the figure 11represents an alternative embodiment in which the projection 26, forming the male member of the sliding connection, is no longer made in one piece with the first part 11a. Indeed, this male member 26 is carried differently by the first part, since it is integrated into a separate mechanical junction part 46 integrating another projection 26', cooperating with a groove 28' provided on the first part 11a. In this way, the cooperation between the projections and grooves 26', 28' is identical or similar to the cooperation between the projections and grooves 26, 28, thus forming two sliding connections in parallel directions. In this alternative, the locking screw 34 passes through the second part 11b, then the two projections 26, 26' of the mechanical junction part 46, and then screws into the first part 11a.

[0069] In the transverse structure 11, the second part 11b is arranged between the first and third parts 11a, 11c, the third part 11c being in fact fixed to an opposite end of the second part 11b using another connecting device 24A, identical or similar to the connecting device 24 between the first and second parts 11a, 11b. This other connecting device 24A, which will not be described in detail due to its identity / similarity with the device 24, is shown in the figure 12 .

[0070] Thus, this other connecting device 24A comprises in particular a male coupling member 26A carried by the third part 11c, the male member taking the form of a projection, as well as a female coupling member 28A in the form of a groove provided on the second part 11b. Here too, the two members 26A, 28A form a sliding connection whose sliding direction 30A is parallel or inscribed in the transverse plane P, and also parallel or coincident with the sliding direction 30 of the other sliding connection.

[0071] In this other connecting device 24A, the groove 28A has, at one 28bA of its two opposite longitudinal ends 28aA, 28bA in the slide direction 30A, an axial slide stop 36A cooperating with one 26bA of the two opposite longitudinal ends of the projection 26A. In addition, on the second part 11b, the two axial slide stops 36, 36A are oriented so as to prevent the movement of the first part 11a relative to the second part 11b in the direction of the third part 11c, and so as to prevent the movement of the third part 11c relative to the second part 11b in the direction of the first part 11a.

[0072] Therefore, in the event of a fall with the basket oriented horizontally, and with a fall direction 48 oriented parallel to the direction in which the three parts 11a, 11b, 11c follow one another (as in the figure 12), the two axial slide stops 36, 36A cause the second part 11b to be compressed between the first and third parts 11a, 11c, under the opposing actions of the two projecting ends 26b, 26bA. This contributes to obtaining reinforced mechanical strength of the wafer 11, and thus to a better guarantee of maintaining its parts relative to each other in the event of the package falling.

[0073] Regardless of the direction of fall and the orientation of the package, such as for example axial fall, lateral fall on normal axis, or lateral fall on oblique axis (for example at 45°), the connecting devices 24, 24A make it possible to benefit from high mechanical resistance at the time of impact. These same connecting devices 24, 24A are also preferably implemented in an identical or similar manner, respectively between the first and fourth parts 11a, 11d, and between the third and fourth parts 11c, 11d.

[0074] Of course, various modifications may be made by those skilled in the art to the storage devices 1 which have just been described, solely by way of non-limiting examples, and the scope of which is defined by the appended claims.

Claims

1. Storage device (1) for transporting and / or storing nuclear fuel assemblies (2, 2'), the storage device being intended to be housed in the cavity (210) of a packaging (200) for transporting and / or storing nuclear fuel assemblies, and including adjacent housings (4, 4'), each intended to receive a nuclear fuel assembly (2, 2'), The storage device comprising a plurality of transverse structures (11) spaced apart from one another in a longitudinal direction (20) of the storage device using spacing means (16), the transverse structures (11) each being arranged in a transverse plane (P) of the storage device, and each comprising a plurality of through-openings (13, 13') for passing nuclear fuel assemblies through, characterised in that at least one of the transverse structures (11) includes a first component (11a) as well as a second component (11b) attached to one another by a connecting device (24), the connecting device comprising: - a male coupling member (26) borne by the first component (11a), the male member taking the form of a projection; - a female coupling member (28) provided on the second component (11b), the female member taking the form of a groove housing the male member and forming therewith a guideway connection the direction of the guideway (30) of which is parallel to or inscribed in the transverse plane (P) wherein the transverse structure concerned lies.

2. Storage device according to claim 1, characterised in that the groove (28) forming the female member has, at one (28b) of its two opposite longitudinal ends in the direction of the guideway (30), a guideway axial abutment (36) cooperating with one (26b) of the two opposite longitudinal ends of the projection (26) forming the male member.

3. Storage device according to claim 2, characterised in that the guideway axial abutment (36) and the associated longitudinal end (26b) of the projection have a complementarity of shape ensuring the holding of the longitudinal end (26b) of the projection in the groove (28), in a stacking direction (38) of the male and female coupling members (26, 28), the stacking direction being orthogonal to the direction of the guideway (30) as well as to an opening plane of the groove.

4. Storage device according to any one of the preceding claims, characterised in that the guideway connection is of unilateral design in a stacking direction (38) of the male and female coupling members (26, 28), the latter preferably having parallelepiped shapes.

5. Storage device according to any one of claims 1 to 3, characterised in that the guideway connection is of bilateral design in a stacking direction (38) of the male and female coupling members (26, 28), the projection and the groove having a complementarity of shape preventing the extraction of the projection (26) outside of the groove (28) via the opening thereof, in the stacking direction (38) of the male and female components.

6. Device according to claim 5, characterised in that the projection has two opposite lateral sides (40) having a complementarity of shape with two opposite lateral sides (42) of the groove with which they respectively cooperate, so as to prevent the extraction of the projection (26) outside of the groove (28) via the opening thereof, in the stacking direction (38) of the male and female members.

7. Device according to claim 6, characterised in that the projection (26) has a section, in a plane orthogonal to the direction of the guideway, in the shape of a dovetail, of a T, or of all or part of a disc.

8. Device according to claim 6 or 7 combined with claim 3, characterised in that said longitudinal end (26b) of the projection (26), as well as its two opposite lateral sides (40), have a continuous profile along the entire length of a U-shaped contour of the projection (26).

9. Storage device according to any one of the preceding claims, characterised in that it comprises a member for locking (34) the guideway connection, holding the male member (26) relative to the female member (28) in the direction of the guideway (30), the member for locking (34) the guideway connection preferably being a screw passing through the male and female members (26, 28).

10. Storage device according to any one of the preceding claims, characterised in that the first and second components (11a, 11b) are two peripheral components of the transverse structure (11), and, preferably, partly delimiting at least one of the through-openings (13) of this transverse structure.

11. Storage device according to any one of the preceding claims, characterised in that the first or the second component (11a, 11b) has a generally straight beam shape, of which the longitudinal central axis of the beam (32) is parallel to or coinciding with the direction of the guideway (30).

12. Storage device according to any one of the preceding claims, characterised in that said transverse structure (11) includes a third component (11c) arranged so that the second component (11b) is located between the first and third components (11a, 11c) that it connects using another connecting device (24A), this other connecting device comprising: - a male coupling member (26A) borne by the third component (11c), the male member taking the form of a projection; - a female coupling member (28A) provided on the second component (11b), the female member taking the form of a groove housing the male member and forming therewith a guideway connection the direction of the guideway (30A) of which is parallel to or inscribed in the transverse plane (P) wherein the transverse structure concerned lies.

13. Storage device according to claim 12, characterised in that in said other connecting device (24A), the groove (28A) forming the female member has, at one (28bA) of its two opposite longitudinal ends in the direction of the guideway (30A), a guideway axial abutment (36A) cooperating with one (26bA) of the two opposite longitudinal ends of the projection (26A) forming the male member, and in that on the second component (11b), the two guideway axial abutments (36, 36A), respectively provided on the two guideway connections, are oriented so as to prevent the movement of the first component (11a) relative to the second component (11b) in the direction of the third component (11c), and so as to prevent the movement of the third component (11c) relative to the second component (11b) in the direction of the first component (11a).

14. Storage device according to any one of the preceding claims, characterised in that the transverse structure (11) includes a ratio between its thickness (E), and its maximum width (L) in the transverse plane (P) wherein it is inscribed, less than 0.1.

15. Package (100) comprising a packaging (200) for storing and / or transporting nuclear fuel assemblies, as well as a storage device (1) according to any one of the preceding claims, housed in a cavity (210) of the packaging, as well as nuclear fuel assemblies arranged in the storage device.