Structure for dissipating heat through natural convection for containers used to transport radioactive materials.

Abstract

The present invention relates to a structure (30) for dissipating heat by natural convection, intended to be mounted on the outer surface of the side of a container (1) for transporting radioactive material, wherein the structure comprises a first heat dissipation subassembly (40a) having a first inclination such that each first main fin (42a) extends in a first direction (7a) in the circumferential direction (7) by being oriented in a first axial direction (8a) on each of the first side (46a) and second side (46b) of a virtual midline plane (P) of the structure, and a second heat dissipation subassembly (40b) having a second inclination different from the first inclination. The first and second subassemblies also form first and second assemblies that integrate first and second generally V-shaped fins (52a, 52b).

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of removal of heat generated by radioactive substances loaded into a container for transporting radioactive substances.

[0002] More precisely, the present invention relates to a structure for dissipating heat by natural convection, for mounting on the outer surface of a side body of a container for transporting radioactive substances such as nuclear fuel assemblies or radioactive waste. BACKGROUND ART

[0003] It is known from the prior art to assemble an external heat removal device around the outer surface of the side body of a container, for the purpose of removing the amount of heat released by the radioactive substance contained in the container to the surrounding environment.

[0004] This heat removal device is specifically designed to limit the temperature reached by different components of the container during transportation of the container, so as to avoid any risk of degradation of said different components, particularly in terms of sealing and radiation protection.

[0005] Furthermore, in addition to being able to perform its main function as a heat exchanger with the surrounding environment, this device is designed to be compatible with the service constraints of the container, such as decontaminability, durability, resistance to external attacks, resistance to operating conditions, or contamination of neutron shielding resins.

[0006] During transportation, the container is in a horizontally lying position, that is, its longitudinal axis is oriented horizontally or substantially horizontally. Therefore, the heat dissipation structure by natural convection needs to exhibit high performance in the horizontal position for transporting the container.

[0007] Known solutions consist of a lining shell that envelops the side body of the container, to which longitudinally straight fins with appropriate cross-sections are welded. These fins are oriented along the vertical direction when the container itself is in a vertical position, and are therefore also referred to as vertical fins.

[0008] However, due to the orientation of the fins, this solution does not allow for proper heat removal when the container is in a horizontal transport position.

[0009] The solution disclosed in Patent Document 1 is also known. While it has a design suitable for heat removal in the vertical position where the container is stored, it is not designed to maximize thermal performance during the horizontal transport of the container. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] French Patent Application Publication No. 3,045,143 [Overview of the project] [Problems that the invention aims to solve]

[0011] Therefore, when the container is in a horizontal transport position, there remains a need to improve the design of the external heat removal device to provide high thermal performance.

[0012] On the one hand, there is a need to facilitate the manufacturing of such external heat removal devices, and on the other hand, to facilitate the implementation of external heat removal devices into containers. [Means for solving the problem]

[0013] To that end, according to a first aspect of the present invention, the present invention is defined by the features of claim 1.

[0014] Therefore, the present invention provides excellent ease of manufacture of the heat dissipation structure while providing high thermal performance when a container equipped with such a structure is positioned in a horizontal transport position. In fact, by cleverly adjusting the angular position of the heat dissipation structure around the longitudinal axis of the container, for example by providing a virtual midline plane of the heat dissipation structure that is oriented vertically or substantially vertically, the tips of the first and second fins positioned on either side of this plane can be oriented upward.

[0015] Therefore, on both sides of the vessel with respect to the virtual midline, guide channels are defined between directly continuous main fins. These guide channels generally form pairs of V-shaped guides, and the ends of these guides are also directed upward.

[0016] This inverted V-shape is advantageous in accelerating air particles within the guide channel, resulting in superior thermal performance. In fact, this is explained by the presence of vortices formed above the guide channel, which facilitate air acceleration between the suction zone located at the base of the inverted V-shape and the exhaust zone located at the tip of the inverted V-shape in these guide channels.

[0017] Furthermore, thanks to the provided design, the heat dissipation structure can also provide sufficient thermal performance when the transport container is in a vertical position and pressed down on its bottom.

[0018] Furthermore, the first and second main fins, which are attached in a stacked manner around the side of the container, make it even easier not only to manufacture these main fins but also to implement them in the container.

[0019] According to a second aspect of the present invention, the present invention is defined by the features of claim 18. In this respect, at least some of the V-shaped tips of the first and second fins, an axial gap is provided between the ends facing the first and second main fins, which allows for improved thermal performance. In fact, such an axial gap allows for the joint definition of a circumferential cooling air conduit, which is therefore positioned in the vertical plane when the container is in a horizontal position. In this position, this significantly improves upward cooling air circulation by convection, thus contributing to better cooling of the container. Each circumferential cooling air conduit can extend over an angular range of 180° or about 180°, or such an angular range can be achieved by providing some of these conduits that are continuous with each other along the circumferential direction. Furthermore, these are preferably some of these circumferential conduits that are axially spaced apart from each other in the heat dissipation structure.

[0020] Furthermore, the present invention preferably has at least one of the following optional features, which may be considered separately or in combination.

[0021] Preferably, on the first side of the virtual midline plane, several first assemblies are adjacent to one another in an axial direction and / or in a circumferential direction, and the number of such assemblies is preferably three or more in each of these two directions, and on the second side of the virtual midline plane, several second assemblies are adjacent to one another in an axial direction and / or in a circumferential direction, and the number of such assemblies is preferably three or more in each of these two directions.

[0022] As will be explained later, the arrangement in which these assemblies are arranged toward one another along the circumferential direction may vary depending on a preferred embodiment of the present invention. Thus, on each side of the virtual midline, the assemblies can be arranged, for example, in a matrix arrangement, or even in a staggered arrangement.

[0023] According to one preferred embodiment of the present invention, the virtual median plane forms a plane of symmetry for the heat dissipation structure, such that each first assembly is symmetrically arranged with respect to one of the second assemblies.

[0024] Preferably, every transverse plane of the structure - a series of first subassemblies on a first side of the virtual median plane, the first subassemblies succeeding one another along the circumferential direction and extending together over an angular range preferably equal to or close to 180°, and - a series of second subassemblies on a second side of the virtual median plane, the second subassemblies succeeding one another along the circumferential direction and extending together over an angular range preferably equal to or close to 180°, or - a series of first subassemblies on a second side of the virtual median plane, the first subassemblies succeeding one another along the circumferential direction and extending together over an angular range preferably equal to or close to 180°, and - a series of second subassemblies on a first side of the virtual median plane, the second subassemblies succeeding one another along the circumferential direction and extending together over an angular range preferably equal to or close to 180°, passes through either one of

[0025] According to another preferred embodiment of the present invention, the heat dissipation structure is asymmetric with respect to every virtual median plane passing through the longitudinal axis.

[0026] Therefore, preferably, every transverse plane of the structure is a series of first subassemblies on the first side and the second side of the virtual median plane, the first subassemblies succeeding one another along the circumferential direction and extending together over an angular range preferably equal to or close to 360°, or A continuity of second subassemblies on the first and second sides of a virtual midline plane, wherein the second subassemblies are continuous with each other along the circumferential direction and extend together over an angular range equal to or close to 360°. It passes through one of the following routes.

[0027] According to yet another preferred embodiment of the present invention, the heat dissipation structure is symmetrical or asymmetrical with respect to a virtual median plane. On the first side of the virtual median plane, several first assemblies are arranged in a staggered pattern, and on the second side of the virtual median plane, several second assemblies are arranged in a staggered pattern.

[0028] Preferably, in this case, every cross-sectional plane of the structure passes through alternating first and second subassemblies along the circumferential direction on the first and second sides of the virtual midline plane, and this alternation preferably extends over an angular range equal to or close to 180°.

[0029] Regardless of the preferred embodiment under consideration, the heat dissipation structure is preferably made using several longitudinal plates that are adjacent to one another along the circumferential direction, and each plate comprises alternating first and second subassemblies along the axial direction.

[0030] Therefore, each plate has main fins with alternating orientations, forming a zigzag configuration along the axial direction. Nevertheless, the plates may have other configurations of main fins without departing from the scope of the present invention. For the implementation of the main fins, it is also possible to replace the plates that are continuous along the circumferential direction with rings that are continuous along the axial direction of the structure around the container body, each ring preferably comprising several adjacent assemblies that are connected to one another along the circumferential direction.

[0031] Preferably, each plate extends over the entire or substantially entire axial length of the structure and is preferably made as a single piece. Nevertheless, these plates with the main fins may be divided along the axial direction without departing from the scope of the invention.

[0032] Preferably, the first and second main fins are made by machining aluminum, copper, or an alloy thereof.

[0033] Preferably, at at least some of the V-shaped tips of the first and second fins, the first and second main fins are in contact with each other, or an axial gap is provided between the ends facing these main fins. In the latter case, the gap provided contributes to forming a circumferential guide through the V-shaped tips of some of the fins, as detailed earlier.

[0034] Preferably, the heat dissipation structure has a generally annular shape with respect to its longitudinal axis.

[0035] Preferably, the heat dissipation structure comprises two directly continuous first assemblies along the circumferential direction, wherein some first main fins of one of the two assemblies are continuous with some first main fins of the other of the two first assemblies, and some second main fins of one of the two assemblies are continuous with some second main fins of the other of the two first assemblies, and a circumferential clearance is provided between the ends facing the two cooperating main fins. In this case, the circumferential clearance, which belongs to the two directly continuous first assemblies along the circumferential direction and is provided between the ends facing the paired cooperating main fins, together defines a conduit extending along the axial direction.

[0036] More generally, regardless of the configuration being considered regarding the relative arrangement between the first assemblies, the circumferential clearance is preferably provided between the ends facing the pair of cooperating main fins and belongs to two directly continuous first assemblies along the circumferential direction, and these circumferential clearances together define a conduit extending along the axial direction. Thus, the circumferential clearance may be observed between two first main fins, between two second main fins, or between a first main fin and a second main fin.

[0037] The presence of one or more axial conduits allows for improved thermal performance when the container is in a vertical storage position. In this regard, it is preferable to ensure that some of these axial conduits are in axial continuity with one another in order to form axial cooling air passages that extend over a large portion of the entire length of the container side, or over the entire length / height or substantially the entire length / height.

[0038] Furthermore, it is preferable that some of these axial cooling passages provided in the structure are spaced apart from each other in the circumferential direction.

[0039] With regard to the axial conduits previously described for the first assembly located on the first side of the virtual midline plane, it should be noted that one or more identical or similar axial conduits may be provided for the second assembly located on the second side of this virtual plane.

[0040] Preferably, at least some of the V-shaped tips of the first and second fins, an axial gap is provided between the ends facing the first and second main fins. The advantages associated with this configuration have been previously mentioned within the scope of the presentation of a second aspect of the present invention.

[0041] It has been noted that each of the features mentioned above, taken alone or in combination with any other of these features, is applicable to the present invention according to a first aspect, applicable to the present invention according to a second aspect, and these two aspects are further combinable with each other.

[0042] Finally, the present invention also relates to a container for transporting radioactive material, which is equipped with the heat dissipation structure described above on the outer surface of the side of the container.

[0043] Other advantages and features of the present invention will become apparent in the non-limiting detailed description below.

[0044] This description applies to the attached drawings. [Brief explanation of the drawing]

[0045] [Figure 1] This is a front view of a container for transporting radioactive material in a lying position, which is equipped with a heat dissipation structure according to a first preferred embodiment of the present invention. [Figure 2] This is a partial cross-sectional view along line II-II in Figure 1. [Figure 3] This is an enlarged front view of a longitudinal plate that forms part of the heat dissipation structure. [Figure 3A] This is an enlarged view of a longitudinal plate similar to the one shown in Figure 3, intended to be positioned on the second side of the virtual midline plane of the annular heat dissipation structure. [Figure 4] This is a cross-sectional view along line IV-IV in Figure 3. [Figure 5] This is a magnified view of a portion of the board shown in Figure 3. [Figure 6] This figure is similar to Figure 5, but represents an alternative embodiment. [Figure 7] This is an enlarged, more detailed perspective view of a portion of a heat dissipation structure according to a first preferred embodiment of the present invention. [Figure 8] This is a front view of the structure shown in the previous figure. [Figure 9] This figure is similar to Figure 7, with the heat dissipation assembly being emphasized. [Figure 10] This figure is similar to the one in Figure 8, with the first and second heat dissipation assemblies highlighted. [Figure 11] This figure is similar to Figure 7, in which the structure is in the form of a second preferred embodiment of the present invention. [Figure 12] This figure is similar to the one in Figure 11, with the first and second heat dissipation assemblies highlighted. [Figure 13] This figure is similar to Figure 8, in which the structure is in the form of a third preferred embodiment of the present invention. [Figure 14] This figure is similar to Figure 13, with the first heat dissipation assembly highlighted. [Figure 15] This is a view of the underside of a ring that forms part of the heat dissipation structure. [Figure 16] This is a perspective view showing a portion of the heat dissipation structure and depicting the cooling air passages in the axial and circumferential directions. [Modes for carrying out the invention]

[0046] Referring first to Figures 1 and 2, a container 1 for transporting radioactive materials such as nuclear fuel assemblies or radioactive waste (not shown) is depicted.

[0047] In Figure 1, container 1 is depicted in a horizontal transport position, which is a so-called lying position, with its longitudinal axis 2 oriented horizontally or substantially horizontally.

[0048] The container has a container bottom 4 opposite the removable lid 6, along the axial direction 8 of the container, which is parallel to the longitudinal axis 2 and also referred to as the longitudinal direction. This longitudinal direction defines a first direction 8a directed from the lid 6 to the bottom 4, and a second direction 8b directed from the bottom 4 to the lid 6, opposite to the first direction 8a.

[0049] The container 1 extends around the axis 2 and comprises side bodies 10 that define a cavity 12 inside for containing radioactive material.

[0050] The side body 10 generally comprises concentric inner shells 14 and outer shells 16, each defining an annular space 18 centered on axis 2. The space 18 is filled with heat conduction means 20, which connects not only the two shells 14, 16 but also neutron protection means 22. The aforementioned means 20, 22 are of conventional design and are therefore not described further.

[0051] The two shells 14 and 16 extend along the circumferential direction 7 of the container, which defines a first direction 7a corresponding to the counterclockwise direction in the cross-section of Figure 2, and a second direction 7b, which is opposite to the first direction 7a and corresponds to the clockwise direction in the same figure.

[0052] The outer shell 16 comprises an annular heat dissipation structure 30, or such a structure is fixedly attached to the outer surface of the container around the shell 16, preferably by welding.

[0053] In some of the preferred embodiments described later, the heat dissipation structure 30 is made using several longitudinal plates 32 that are welded to one another and, possibly, also to the heat conduction elements 20 of the container, and are connected to one another along the circumferential direction 7. According to an alternative described later and corresponding to a first aspect of the present invention, the longitudinal plates 32 can be replaced by rings that are stacked around the container sides along the axial direction.

[0054] Each longitudinal plate 32 is made as a single, integrated piece, while having an axial length "L" that extends along the entire axial length of the structure 30. This axial length of the plate 32 is close to the overall axial length of the container, as it is preferable that each plate covers all or most of the axial length of the side body 10 of the container, leaving only the lid 6 and bottom 4 uncovered. The axial length "L" of the plate 32 can be between 2m and 5m.

[0055] The finned plate 32 has a width in the circumferential direction that is much smaller than its axial length. Therefore, by arranging the plate 32 from end to end in this direction 7, the heat dissipation structure 30 has a generally annular shape centered on axis 2, which also corresponds to its longitudinal axis. The number of plates 32 can be between 5 and 40.

[0056] As can be seen in Figure 2, each plate 32 has a base in the form of a planar or substantially planar rectangular plate, the base having two opposite longitudinal edges. As previously discussed, the bases of the plates 32 are assembled end to end by welding at their mutually facing edges to reconstruct the outer shell 16 or to extend around the outer shell 16.

[0057] One of the boards 32 is partially depicted in Figures 3 and 4.

[0058] The plate 32 is provided with alternating first and second partial assemblies 40a and 40b, which are dedicated to cooling by having main cooling fins that protrude radially from the base of the plate 32 along the axial direction 8.

[0059] More precisely, each first heat dissipation subassembly 40a comprises first main fins 42a parallel to each other. These first main fins 42a are locally inclined with respect to two directions 7, 8, that is, forming a non-zero angle with each of these two directions. The first main fins 42a are constructed to have a first inclination denoted A1 in Figure 3, which illustrates the fact that each first main fin 42a extends in a first orientation 7a in the circumferential direction 7 when oriented in a first axial orientation 8a. Using the notation, the angle between the main fins 42a and each of the two directions 7, 8 can be as much as 45°, or more broadly, between 30° and 60°.

[0060] Similarly, each second heat dissipation subassembly 40b comprises second main fins 42b parallel to each other. These second main fins 42b are locally inclined with respect to two directions 7, 8, that is, they form a non-zero angle with respect to each of these two directions. The second main fins 42b are constructed to have a second inclination denoted A2 in Figure 3, and Figure 3 illustrates the fact that each second main fin 42b extends in a second direction 7b in the circumferential direction 7, oriented in a first axial direction 8a. Using the notation, the angle between the main fin 42b and each of the two directions 7, 8 may be around 45°, or more broadly, between 30° and 60°.

[0061] Due to the alternating arrangement of the first subassemblies 40a and the second subassemblies 40b within the plate 32, they are taken together, and then the main fins 42a and 42b with opposite inclinations have a so-called zigzag configuration along the plate. Preferably, the main fins 42a and 42b have a constant cross-section.

[0062] Each subassembly 40a, 40b has a generally square or rectangular shape, with its sides locally parallel to directions 7 and 8, respectively. Several main fins 42a, 42b are provided within each subassembly 40a, 40b, in numbers ranging from 5 to 20. Due to the inclination of the main fins, the lengths of the main fins differ within each subassembly 40a, 40b.

[0063] A first guideway 44a for circulating cooling external air is formed between two directly continuous first main fins 42a, and a second guideway 44b for circulating cooling external air is formed between two directly continuous second main fins 42b. The main fins 42a and 42b have a radial height of 1 to several centimeters, while the width of the guideways 44a and 44b defined by these main fins 42a and 42b is also preferably on the order of 1 to several centimeters.

[0064] The plate 32 depicted in Figures 3 and 4 is intended to be positioned on one side between the first and second sides of a virtual median plane P of the structure 30, which passes through axis 2 and is vertical or substantially vertical in this case. In other words, the virtual median plane P substantially divides the structure 30 into two C-shaped half-shells facing each other.

[0065] With respect to the first side 46a of the median plane, which can be seen in Figure 7 and corresponds to the first side of structure 30, each plate 32 is of the type depicted in Figures 3 and 4. Each pair of adjacent first and second subassemblies 40a, 40b, which are directly continuous along the axial direction 8, form a first assembly 50a in which at least some of the first and second main fins 42a, 42b internally form pairs of first generally V-shaped fins 52a that are continuous with each other along the circumferential direction. With respect to these plates 32 on the first side 46a of plane P, the V-shaped tips are directed in a first circumferential direction 7a, that is, upward to promote airflow by natural convection.

[0066] Similarly, with respect to the second side 46b of the midline plane, which also corresponds to the second side of structure 30, each plate 32 has a design similar to that depicted in Figures 3 and 4 and very concisely depicted in Figure 3A. In fact, according to another feature of the present invention, each pair of adjacent first and second subassemblies 40a, 40b that are directly continuous along the axial direction 8 form a second assembly 50b in which at least some of the first and second main fins 42a, 42b internally form a pair of second generally V-shaped fins 52b that are continuous with each other along the circumferential direction. With respect to these plates 32 on the second side of plane P, the V-shaped tips are directed in a second circumferential direction 7b, i.e., upward toward the lying container, in order to further promote airflow by natural convection.

[0067] It should be noted that the first and second main fins 42a, 42b are preferably made by machining aluminum, copper, or an alloy thereof. During this machining, the two main fins 42a, 42b may be provided in contact with each other at the V-shaped tips formed by the fins 52a, 52b, as depicted in Figure 5. The V-shaped tips are preferably all located on the same circle centered on axis 2. This provides material continuity for the fins 52a, 52b, although other embodiments, as depicted in Figure 6, may be considered. This embodiment corresponds to a second aspect specific to the present invention, namely, further machining to provide an axial gap 56 between the ends of the two main fins 42a, 42b. Naturally, this gap 56 can be provided even when the main fins 42a, 42b are made by techniques other than machining the longitudinal plate 32.

[0068] The presence of these gaps 56, as depicted in Figure 6, contributes to the formation of circumferential passages through the V-shaped tips of several fins 52a, 52b to further promote upward cooling air circulation around the container. Figure 16 illustrates in more detail this second embodiment of the invention, applicable to the first and / or second sides of a virtual midline plane. The aforementioned axial gaps 56 allow for the joint definition of circumferential cooling air passages 70 within each of the first and second assemblies 50a, 50b. Each circumferential passage 70 preferably extends over the entire circumferential length of its assembly 50a, 50b, and some of these passages 70 in different assemblies are in circumferential continuity with one another. Thus, together, the circumferential passages 70 form circumferential passages, each extending over an angular range of 180° or about 180°, and these passages are axially spaced apart from one another. Nevertheless, these circumferential passages can still be interrupted circumferentially without departing from the scope of the invention.

[0069] Therefore, in the horizontal position of the container, the periphery guides 70 are arranged in the vertical plane. This significantly improves upward cooling air circulation by natural convection, and thus contributes to better cooling of the container. This advantage is further achieved even when each of these periphery guides 70 has a discontinuous lateral demarcation between the main fins 42a and 42b in each guide path 44a and 44b.

[0070] As is evident from the entire application, it should be noted that this second aspect of the present invention can be implemented in all preferred embodiments described herein.

[0071] As depicted in Figure 5, in the horizontal transport position of the container, air circulates upward in the guide paths 44a and 44b between the first fins 52a, and the same applies between the second fins 52b of the plate 32 located on the second side of the virtual midline plane (Figure 3A).

[0072] More precisely, as the longitudinal plate 32 is heated, natural convection occurs, directing air into the guide channels 44a and 44b, guiding it upward through these channels, where it then merges with air coming from the guide channels of the same first assembly 50a / second assembly 50b facing those guide channels. This collision at the exit of the guide channels at the inverted V-shaped tips causes the air to escape vertically upward. Simultaneously, air vortices and recirculation are also created above the fins 52a and 52b and the guide channels 44a and 44b, promoting air acceleration in these guide channels. As this column of air travels along the circumferential line formed by the tips of these inverted V-shapes, it is amplified by the continuous supply of guide channels, pushing the air further away from the surface. This forced exhaust creates upward vortex movement fed from the base of the inverted V-shapes, thereby forming an intake conductor and enabling forced circulation in the conductor.

[0073] Figures 7 to 10 depict a first preferred embodiment of the present invention in which a virtual median plane P forms a plane symmetrical with respect to the heat dissipation structure 30. In this embodiment, on the first side 46a of plane P, all plates 32 are identical and together form a C-shaped half-shell. Thus, there are several adjacent first assemblies 50a that follow each other along each of the two directions 7 and 8, and the number of first assemblies 50a is preferably three or more in each of these two directions. As depicted by the added rectangles in Figures 9 and 10, the adjacent first assemblies 50a take the form of a so-called matrix, formed by axial rows and circumferential columns.

[0074] Similarly, on the second side 46b of plane P, all plates 32 are identical to each other but different from the plates located on the first side 46a. In fact, as can be seen in Figures 7 and 9, the plates 32 are arranged in the same axial direction as the first subassemblies 40a and the second subassemblies 40b, but with a half-pitch offset relative to the plates 32 on the first side 46a, and the overall pitch is formed by the overall axial length of the assemblies 50a and 50b. This makes it possible to ensure that each first assembly 50a on the first side is arranged symmetrically with respect to one of the second assemblies 50b on the second side. In fact, the plates 32 on the second side 46b also together form a C-shaped half-shell. Thus, there are several adjacent second assemblies 50b that follow each other along each of the two directions 7 and 8, and the number of second assemblies 50b is preferably three or more in each of these two directions. As depicted by the thick rectangle added in Figure 9, the adjacent second assembly 50b takes the form of a so-called matrix, with rows in the axial direction and columns in the circumferential direction.

[0075] In this first preferred embodiment, every cross-sectional plane of the structure 30 is Passing through a series of first subassemblies 40a on the first side 46a that continue toward each other along direction 7 and preferably extend together over an angular range equal to or close to 180°, then passing through a series of second subassemblies 40b on the second side 46b that continue toward each other along direction 7 and preferably extend together over an angular range equal to or close to 180°, or The continuity of the first subassemblies 40a on the second side 46b, which are continuous with each other along direction 7 and preferably extend together over an angular range equal to or close to 180°, and the continuity of the second subassemblies 40b on the first side 46a, which are continuous with each other along direction 7 and preferably extend together over an angular range equal to or close to 180°. It is one of the following:

[0076] It is noted that, on the first side 46a, for any two first assemblies 50a that are directly continuous along the circumferential direction 7, some first main fins 42a of one of the two assemblies 50a are continuous with some first main fins 42a of the other of the two assemblies 50a, respectively. The same applies to some second main fins 42b of these two assemblies 50a. This allows one of the two assemblies 50a to extend the axial length of some first fins 52a formed by the other of these two assemblies 50a, and consequently to have the first fins 52a along the circumferential direction 7 for all or substantially all of the same axial extension. The geometric continuity between some first main fins 42a of two directly continuous assemblies 50a in the circumferential direction 7 and between some second main fins 42b of these two assemblies 50a does not prevent the provision of circumferential clearance between the ends facing the two cooperating main fins 42a, 42b, as can be seen in the figure. These features are also observed in the second assembly 50b. Similarly, this principle of circumferential clearance is applicable to all preferred embodiments described herein and can be implemented regardless of the relative arrangement of the main fins 42a, 42b, in particular. For example, this circumferential clearance may be observed between the end of a first main fin 42a and the end of a second main fin 42b of another directly continuous assembly 50a, 50b facing that end.

[0077] This principle is also illustrated in Figure 16, showing that the circumferential clearance 74 defines together a conduit 72 that extends along the axial direction 8 and preferably along the entire interface between two directly continuous assemblies, whether it be the first assembly 50a or the second assembly 50b. It should also be noted that, using the diagram, each of these axial conduits 72 has a discontinuous lateral definition between the main fins 42a, 42b in each of the main conduits 44a, 44b.

[0078] The presence of one or more axial conduits 72 of this type allows for improved thermal performance when the container is in a vertical storage position. In this regard, it is preferably ensured that some of these axial conduits 72 are in axial continuity with one another in order to form axial cooling air passages that extend over a large portion of the entire length of the container side, or over the entire length / height or substantially the entire length / height.

[0079] Furthermore, it is preferable that some of these axial cooling passages provided in the structure are spaced apart from each other in the circumferential direction.

[0080] In this regard, it should be noted that a continuity of material may be provided between the main fins 42a, 42b of two directly continuous assemblies 50a or 50b along the axial direction 8. Alternatively, as depicted in Figure 16, an axial clearance may be provided between the ends facing two cooperating main fins. This is identical or similar to the aforementioned circumferential conduit 70, and allows for the formation of other circumferential conduits 76 that are alternately arranged in the axial direction with the circumferential conduit 70.

[0081] Here, it is noted that these features are observed on both the first side 46a and the second side 46b of the virtual median plane P.

[0082] A second preferred embodiment of the present invention is shown in Figures 11 and 12. The second embodiment is broadly similar to the first embodiment described above, except that all plates 32 are identical on the first and second sides 46a, 46b of the virtual median plane P, so the structure 30 no longer has a plane of symmetry passing through axis 2. This method facilitates the manufacturing and mounting of the structure 30 by providing a reference for only one plate 32.

[0083] The result of this arrangement is that the first assembly 50a on the first side 46a is axially offset by half a pitch relative to the second assembly 50b on the second side 46b, as highlighted by the addition of the rectangle in Figure 12.

[0084] In this second preferred embodiment, any cross-sectional plane of the structure 30 passes through either a continuity of the first subassemblies 40a on the first and second sides 46a, 46b that preferably extends together over an angular range equal to or close to 360°, or a continuity of the second subassemblies 40b on the first and second sides 46a, 46b that preferably extends together over an angular range equal to or close to 360°.

[0085] A third preferred embodiment of the present invention is shown in Figures 13 and 14. The third embodiment is substantially similar to the embodiments described above, but is distinguished by the fact that on the first side 46a, there are several first assemblies 50a, preferably all of the first assemblies 50a, arranged in a staggered pattern. In fact, any two second directly continuous assemblies 50a along the circumferential direction 7 are axially offset from each other by a pitch value of half, as highlighted by the rectangle in Figure 14. For this reason, on this first side 46a of the virtual median plane P, two plates 32 of different designs alternate along the circumferential direction. Their designs differ in that, within the scope of the first preferred embodiment, there is an axial offset of half a pitch between the plates 32 on the first side and the plates 32 on the second side, as observed in Figures 7 to 10.

[0086] This axial offset of half a pitch between the plates 32 is not described in this third preferred embodiment, but is also observed on the second side 46b for the formation of the second assembly 50b. Thus, on this second side, there are also two types of alternately arranged plates 32 that form half of the shell of the structure 30, and these two types of plates are preferably the same as the plates arranged on the first side.

[0087] In this regard, it is noted that the plate 32 on the first side may be symmetric with respect to the plate 32 on the second side with respect to the virtual median plane P. Alternatively, an axial misalignment is provided between the plate 32 on the first side and the plate 32 on the second side, which means that the structure 30 is not symmetric with respect to any median plane of the structure passing through axis 2.

[0088] Therefore, in this third preferred embodiment, every cross-sectional plane of the structure 30 passes through the alternating first and second subassemblies 40a, 40b along the circumferential direction 7 on each of the first and second sides 46a, 46b, so that this alternation on each of the two sides preferably extends over an angular range equal to or close to 180°.

[0089] Regardless of the embodiment under consideration, referring to Figure 3A, not only the main fins 42a, 42b, but also the first and second guide paths 44a, 44b defined between these fins 42a, 42b, preferably satisfy the condition d / Ep ≤ 2.5, and more preferably the condition d / Ep ≤ 1.5. It should be noted that "d" corresponds to the width of each main air circulation guide path 44a, 44b defined between any two directly continuous main fins, and this width is, for example, between 10 mm and 50 mm, and is preferably the same for all guide paths and along all of these guide paths. Also, "Ep" corresponds to the thickness of each main fin, and this thickness Ep is preferably the same for all of these main fins 42a, 42b.

[0090] The aforementioned ratio values ​​clearly indicate the relatively large thickness of the main fins 42a and 42b. As a result, these values ​​can provide sufficient fire resistance to the container, even if these fins are made from aluminum or an alloy thereof.

[0091] Figure 15 illustrates a first aspect of the present invention that may be implemented in each of the preferred embodiments described. As previously discussed, the longitudinal plates 32 are replaced by rings 80 (only one can be seen in Figure 15) which are stacked along the axial direction 8 and intended to be positioned around the sides of the container.

[0092] To do this, each ring 80 is continuous over 360° around the axis 2 by integrating a base which is preferably intended to slide around the outer surface of the container side. The rings 80, which have main fins 42a, 42b projecting radially outward on the radial outer surface of the base, are preferably introduced one by one around the container side during manufacturing to gradually form the desired outer skin around the side 10.

[0093] There are many rings of this kind that can be stacked in this way, in numbers ranging from 5 to 30, depending on the length of the container.

[0094] Furthermore, the axial thickness of each ring 80 is preferably one-tenth the outer diameter of the ring 80, determined by the far ends of the main fins 42a and 42b. This ratio may be even greater without departing from the scope of the present invention.

[0095] In the example depicted in Figure 15, each wheel 80, with its first and second main fins 42a, 42b, defines the circumferential continuity of the first and second assemblies 50a, 50b. Alternatively, each wheel 80 may incorporate only the first main fin 42a forming the first subassembly 40a, or only the secondary fin 42b forming the second subassembly 40b. In these cases, the first and second assemblies 50a, 50b are reconstructed by stacking two wheels 80 that are directly continuous in the axial direction 8. Furthermore, for this purpose, there may be two wheels 80 having the same or similar design but with opposite axial orientations, inserted around the side of the container 10.

[0096] According to other alternatives, it may be provided to repeat a series of three stacked rings 80 with an intermediate ring corresponding to the ring in Figure 15. Thus, two other rings 80 positioned on the first side and the second opposite side of the intermediate ring, respectively, have main fins 42a, 42b extending from the main fins 42a, 42b of the intermediate ring.

[0097] Naturally, various modifications may be made by those skilled in the art, as described below, merely as non-limiting examples. [Explanation of Symbols]

[0098] 1 container 2 Longitudinal axis 4 Bottom of container 6 Lid 7. Surrounding direction 7a First circumferential orientation 7b Second circumferential orientation 8. Axial direction, longitudinal direction 8a First orientation 8b Second orientation 10 Lateral body 14 Internal Shell 16 External Shell 18. Ring Space 20 Heat conduction means, heat conduction elements 22 Neutron protection measures 30 Heat dissipation structure 32 Longitudinal signs 40a First heat dissipation subassembly 40b Second heat dissipation subassembly 42a First main fin 42b Second main fin 44a First Leading Route 44b Second leadership route 46a First side 46b Second side 50a First assembly 50b Second assembly 52a First generally V-shaped fin 52b Second generally V-shaped fin 56 Axial clearance 70. Peripheral Directional Conduit 72 Axial guideway 76 Peripheral Directional Conduits 80 wheels A1 First slope A2 Second slope Axial length of L plate 32 P Virtual midline

Claims

1. A natural convection heat dissipation structure (30) intended to be mounted on the outer surface of the side of a container (1) for transporting radioactive material, wherein the heat dissipation structure extends around a longitudinal axis (2) of the structure, which is intended to correspond to the longitudinal axis of the container that is oriented horizontally when the container is in a horizontal transport position. The heat dissipation structure is such that, on each of the first side (46a) and second side (46b) of the virtual median plane (P) of the structure passing through its longitudinal axis (2), A first heat dissipation subassembly (40a) comprises first main fins (42a) that are parallel to each other and locally inclined with respect to the circumferential direction (7) and the axial direction (8) of the structure, such that each first main fin (42a) has a first inclination (A1) such that it extends in a first direction (7a) of the circumferential direction (7) which is oriented in a first direction (8a) of the axial direction, A second heat dissipation subassembly (40b) comprising second main fins (42b) which are parallel to each other and locally inclined with respect to the circumferential direction (7) and the axial direction (8) of the structure, such that each second main fin (42b) has a second inclination (A2) such that it extends in a second direction (7b) of the circumferential direction (7) opposite to the first direction (7a) which is oriented in the first direction (8a) of the axial direction (8), and It must have at least the following: On the first side (46a) of the virtual median plane (P), the first subassembly (40a) and the second subassembly (40b) are adjacent to each other along the axial direction (8) such that at least two of each of the first and second main fins (42a, 42b) form a first generally V-shaped fin (52a) that is continuous with each other along the circumferential direction (7), with the tips of the V-shapes facing the first circumferential direction (7a), and the first subassembly (50a) is adjacent to each other. On the second side (46b) of the virtual midline plane, the first subassembly (40a) and the second subassembly (40b) are adjacent to each other along the axial direction (8) such that at least two of each of the first and second main fins (42a, 42b) form a second generally V-shaped fin (52b) that is continuous with each other along the circumferential direction (7), with the tips of the V-shapes facing the second circumferential direction (7b), and the second subassembly (40b) is adjacent to each other. The heat dissipation structure comprises several of the first and second assemblies (50a, 50b) in which the first and second main fins (42a, 42b) are formed in a continuous ring (80) along the axial direction (8) of the structure, and the ring is intended to be positioned around the side body (10) of the container. A natural convection heat dissipation structure (30) characterized by the above.

2. On the first side (46a) of the virtual median plane (P), several first assemblies (50a) are adjacent to one another in a continuous manner along the axial direction (8) and / or along the circumferential direction (7), and the number of such assemblies is preferably three or more in each of these two directions. On the second side (46b) of the virtual median plane (P), several second assemblies (50b) are adjacent to one another in succession along the axial direction (8) and / or along the circumferential direction (7), and the number of such assemblies is preferably three or more in each of these two directions. The heat dissipation structure (30) according to claim 1, characterized by the above.

3. The heat dissipation structure (30) according to claim 2, characterized in that the virtual median plane (P) forms a plane symmetrical with respect to the heat dissipation structure, and each first assembly (50a) is arranged symmetrically with respect to one of the second assemblies (50b).

4. Every cross-sectional plane of the aforementioned structure is A continuity of first subassemblies (40a) on the first side (46a) of the virtual midline plane, wherein the first subassemblies (40a) are continuous with each other along the circumferential direction (7) and preferably extend together over an angular range equal to or close to 180°, and A continuity of second subassemblies (40b) on the second side (46b) of the virtual plane, wherein the second subassemblies (40b) are continuous with each other along the circumferential direction (7) and extend together over an angular range equal to or close to 180°, or A continuity of first subassemblies (40a) on the second side (46b) of the virtual midline plane, wherein the first subassemblies (40a) are continuous with each other along the circumferential direction (7) and preferably extend together over an angular range equal to or close to 180°, and A continuity of second subassemblies (40b) on the first side (46a) of the virtual midline plane, wherein the second subassemblies (40b) are continuous with each other along the circumferential direction (7) and preferably extend together over an angular range equal to or close to 180°. either The heat dissipation structure (30) according to claim 2 or 3, characterized by passing through a certain point.

5. The heat dissipation structure (30) according to claim 2, characterized in that the heat dissipation structure (30) is asymmetric with respect to any virtual median plane (P) passing through the longitudinal axis (2).

6. Every cross-sectional plane of the aforementioned structure is A continuity of first subassemblies (40a) on the first and second sides (46a, 46b) of the virtual median plane (P), wherein the first subassemblies (40a) are continuous with each other along the circumferential direction (7), preferably extending together over an angular range equal to or close to 360°, or A continuity of second subassemblies (40b) on the first and second sides (46a, 46b) of the virtual median plane (P), wherein the second subassemblies (40b) are continuous with each other along the circumferential direction (7) and preferably extend together over an angular range equal to or close to 360°, or any of the continuities of second subassemblies (40b). A heat dissipation structure (30) according to claim 2 or 5, characterized by passing through a certain point.

7. The heat dissipation structure (30) is symmetrical or asymmetrical with respect to the virtual median plane (P), On the first side (46a) of the virtual midline plane, several first assemblies (50a) are arranged in a staggered pattern, On the second side (46b) of the virtual midline plane, several second assemblies (50b) are arranged in a staggered pattern. The heat dissipation structure (30) according to claim 2, characterized by the above.

8. The heat dissipation structure (30) according to claim 2 or 7, characterized in that any cross-sectional plane of the structure passes through alternating first and second subassemblies (40a, 40b) along the circumferential direction (7) on the first and second sides (46a, 46b) of the virtual midline plane, and the alternations preferably extend over an angular range equal to or close to 180°.

9. The heat dissipation structure (30) according to any one of claims 1 to 8, wherein the heat dissipation structure (30) is made using several longitudinal plates (32) that are adjacent to one another along the circumferential direction (7), and each plate comprises alternating first and second subassemblies (40a, 40b) along the axial direction (8).

10. The heat dissipation structure (30) according to claim 10, characterized in that each longitudinal plate (32) extends over the entire or substantially entire axial length of the structure and is preferably made as a single piece.

11. The heat dissipation structure (30) according to any one of claims 1 to 10, characterized in that the first and second main fins (42a, 42b) are preferably made by machining aluminum, copper, or an alloy thereof.

12. A heat dissipation structure (30) according to any one of claims 1 to 11, characterized in that at least some of the V-shaped tips of the first and second fins (52a, 52b), the first and second main fins (42a, 42b) are in contact with each other, or an axial gap (56) is provided between the ends of these main fins (42a, 42b).

13. The heat dissipation structure (30) according to any one of claims 1 to 12, characterized in that the heat dissipation structure (30) has a generally annular shape centered on its longitudinal axis (2).

14. The heat dissipation structure (30) comprises two first assemblies (50a) that are directly continuous along the circumferential direction (7), wherein some first main fins (42a) of one of the two assemblies (50a) are continuous with some first main fins (42a) of the other of the two first assemblies (50a), and some second main fins (42b) of one of the two assemblies (50a) are continuous with some second main fins (42b) of the other of the two first assemblies (50a), and the circumferential clearance is provided between the ends facing the two main fins (42a, 42b) that cooperate in pairs.

15. The heat dissipation structure (30) according to claim 14, characterized in that the circumferential clearance provided between the ends of the two directly continuous first assemblies (50a) along the circumferential direction (7) and facing the two cooperating main fins (42a, 42b) together defines a guideway (72) extending along the axial direction (8).

16. A heat dissipation structure (30) according to any one of claims 1 to 13, characterized in that circumferential clearances cooperate in pairs and are provided between ends facing the main fins (42a, 42b) belonging to two first directly continuous assemblies (50a) along the circumferential direction (7), and these circumferential clearances together define a guideway (72) extending along the axial direction (8).

17. A heat dissipation structure (30) according to any one of claims 1 to 16, characterized in that at least some of the V-shaped tips of the first and second fins (52a, 52b), an axial gap (56) is provided between the ends facing the first and second main fins (42a, 42b).

18. A natural convection heat dissipation structure (30) intended to be mounted on the outer surface of the side of a container (1) for transporting radioactive material, wherein the heat dissipation structure extends around a longitudinal axis (2) of the structure, which is intended to correspond to the longitudinal axis of the container that is oriented horizontally when the container is in a horizontal transport position. The heat dissipation structure is such that, on each of the first side (46a) and second side (46b) of the virtual median plane (P) of the structure passing through its longitudinal axis (2), A first heat dissipation subassembly (40a) comprises first main fins (42a) that are parallel to each other and locally inclined with respect to the circumferential direction (7) and the axial direction (8) of the structure, such that each first main fin (42a) has a first inclination (A1) such that it extends in a first direction (7a) of the circumferential direction (7) which is oriented in a first direction (8a) of the axial direction, A second heat dissipation subassembly (40b) comprising second main fins (42b) that are parallel to each other and locally inclined with respect to the circumferential direction (7) and the axial direction (8) of the structure, such that each second main fin (42b) has a second inclination (A2) different from the first inclination, such that it extends in a second circumferential direction (7b) opposite to the first direction (7a) which is oriented in the first direction (8a) of the axial direction (8); It must have at least the following: On the first side (46a) of the virtual median plane (P), the first subassembly (40a) and the second subassembly (40b) are adjacent to each other along the axial direction (8) such that at least two of each of the first and second main fins (42a, 42b) form a first generally V-shaped fin (52a) that is continuous with each other along the circumferential direction (7), with the tips of the V-shapes facing the first circumferential direction (7a), and the first subassembly (50a) is adjacent to each other. On the second side (46b) of the virtual midline plane, the first subassembly (40a) and the second subassembly (40b) are adjacent to each other along the axial direction (8) such that at least two of each of the first and second main fins (42a, 42b) form a second generally V-shaped fin (52b) that is continuous with each other along the circumferential direction (7), with the tips of the V-shapes facing the second circumferential direction (7b), and the second subassembly (40b) is adjacent to each other. At least some of the V-shaped tips of the first and second fins (52a, 52b), an axial gap (56) is provided between the ends facing the first and second main fins (42a, 42b). A natural convection heat dissipation structure (30) characterized by the above.

19. A container (1) for transporting radioactive material, comprising a heat dissipation structure (30) according to any one of claims 1 to 18, which is mounted on the outer surface of the side of the container.

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